Natural Solution for Diabetes

Reverse Diabetes Now

Reverse Your Diabetes by Matt Traverso was developed with the objective of curing diabetes effortlessly and forever. Reverse Your Diabetes Today guarantees to help patients end this illness in just 3 weeks! The treatment requires absolutely no drugs nor medication or medical interventions for it to be successful. You will learn the real root causes of this condition, truth about germs, and how to improve the quality of our cells with a lot of useful nutrition tips. Finally, what people will learn, of course, is a concrete treating plan for diabetes that helps to kick the disease out of your body once and for all. In fact, this treatment is very simple, but it can stop your anxiety about diabetes effectively and fast! Reverse Diabetes Today PDF is an extremely comprehensive treatment that encourages people to make positive changes in daily habits, more concretely, dieting, regularly exercising, and weight managing routines to reverse diabetics. Continue reading...

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Basic principles of the euglycaemic hyperinsulinaemic clamp technique

The hyperinsulinaemic euglycaemic clamp technique was developed by Andres etal. (1966) and further developed and widely studied by DeFronzo etal. (1979) (see also Sherwin etal. 1974 Insel etal. 1975). From a mechanistic point of view, this technique breaks the physiologically-operating feedback loop between blood glucose concentration and pancreatic insulin secretion and applies a negative feedback principle to the system regulating the blood glucose concentration (Bergman etal. 1985). In the postabsorptive state of nondiabetic individuals, the rate of endogenous glucose output originating from hepatic ( 95 ) and renal ( 5 ) glucose release exactly matches the rate of whole body glucose utilisation, resulting in constant glycaemia (Figure 4.3). The administration of exogenous insulin under these conditions reduces endogenous glucose output and increases whole body glucose utilisation, which both result in a decline of blood glucose concentration. This decline can be prevented when an...

Standardised indices of insulin sensitivity derived from the M value

For purposes of comparison, M values should be standardised (Ferrannini & Mari 1998). The steady state rate of whole body glucose metabolism is frequently normalised for bodyweight (Mbw), fat free mass (Mffm), rate of resting energy expenditure (Mree) and steady state plasma insulin concentration during the clamp (M I) (Bergman etal. 1985 Ferrannini & Mari 1998). Normalisation of the M value for the mean steady state concentration of plasma glucose yields the metabolic clearance rate of glucose (MCR) (Ferrannini & Mari 1998), which is able to account for small differences in glycaemia during a clamp. Any of these normalisations may be advantageous is some cases but bear pitfalls in others. Although several studies could demonstrate adipose tissue glucose uptake under insulin stimulated conditions in vivo (Bjorntorp etal. 1971 Virtanen etal. 2002), it is recommended that

Insulin stimulated whole body glucose metabolism

During euglycaemic hyperinsulinaemia, skeletal muscle is primarily responsible for the insulin dependent increase of whole body glucose metabolism (Figure 4.4 and 4.6A) DeFronzo etal. 1985). The contribution of the liver to whole body glucose metabolism is small under these conditions. However, splanchnic glucose uptake and thus the contribution of the liver to whole body glucose metabolism increases under hyperglycaemic hyperin-sulinaemic conditions (Basu et al. 2004 Krssak et al. 2004). Insulin stimulated whole body glucose metabolism depends on two major metabolic pathways glucose oxidation and nonox-idative glucose metabolism. Nonoxidative glucose metabolism is primarily represented by glycogen synthesis, and skeletal muscle is the tissue accounting for the majority of insulin stimulated glycogen synthesis (Shulman etal. 1990). In insulin resistant states, lower rates of skeletal muscle glycogen synthesis are responsible for the reduction of insulin stimulated whole body glucose...

Regulation of endogenous glucose output during euglycaemic hyperinsulinaemia

Of insulin and glucagon (Cherrington 1999). Although irrelevant during a hyperinsulinaemic clamp test performed at euglycaemia, hyperglycaemia per se also exerts a powerful inhibitory effect on endogenous glucose output (Bell etal. 1986). Because glucoregulatory hormones other than insulin, such as glucagon, are only gradually suppressed during hyperinsulinaemic euglycaemic clamp tests (Prager etal. 1987 Lewis etal. 1998), two other factors essentially impact on endogenous glucose output. These factors are the degree of hyperinsulinaemia per se and the insulin sensitivity of hepatic glucose output. Since insulin is physiologically secreted into the splanchnic circulation, portal vein plasma concentrations of insulin exceed those in peripheral and arterial plasma. The physiological range of the ratio between portal venous and peripheral venous insulin concentrations is approximately 2-2.5 1 (Waldhausl etal. 1982). During a clamp experiment, endogenous insulin secretion can be monitored...

Preparation of the insulin infusion

The insulin infusate is prepared with human insulin, which is added to isotonic saline. The insulin infusion pump must be calibrated and must provide sufficient fine gears to allow the administration of the calculated insulin dose. In order to prevent the absorption of the hormone in plastic surfaces, 2 ml of the individual's blood per 48 ml of the infusate is added to the infusate (Sherwin etal. 1974 DeFronzo etal. 1979). The effectiveness of this method can be proven by measuring the insulin recovery in the infusate after it is pumped through the infusion lines (Sherwin etal. 1974 Insel etal. 1975 DeFronzo etal. 1979). This may be of special interest when clamp experiments are performed with investigative apparatus such as nuclear magnetic resonance spectrometers or positron emission tomography, which complicate the use of infusion pumps with short infusion lines.

Example of a protocol for insulin infusion

The following paragraph describes the preparation of an insulin infusate for a hyperinsuli-naemic (40 mU-m-2-min-1) euglycaemic clamp test. Table 4.3 provides an infusion scheme for the priming of the insulin space. The continuous infusion rate of the insulin infusion pump is chosen to be 20 ml per hour. 2 ml of blood are drawn from the participant and are promptly added to 48 ml of isotonic saline in a sterile syringe (50 ml). Then the required dose of human insulin is added, calculated as follows INSULIN (1 U ) - Ins(40 mU m-2 min-1) BSA(m2) 60(min) Syringe Vol. (50 ml) (. .) Pump factor (20 ml h) 1000 INSULIN (I.U.) 6 BSA(m2) where Ins represents the rate of insulin infusion normalised to body surface area, BSA the body surface area (expressed in square metres), and the pump factor is the continuous infusion rate of the insulin infusion pump (ml h, here chosen to be 20 ml per hour). The number 1,000 in the denominator converts the insulin units from mU to I.U. If more than 50 ml of...

Reproducibility of insulin sensitivity obtained from clamp tests

Studies on the reproducibility have been performed under several metabolic conditions including lean and obese as well as glucose tolerant and intolerant individuals (DeFronzo etal. 1979 Del Prato etal. 1986 Morris etal. 1997 Bokemark etal. 2000 Soop etal. 2000). The conclusive finding of these studies is that the M value obtained from the hyperinsuli-naemic euglycaemic clamp test is a repeatable measure of insulin sensitivity. In these studies the time interval for the repetitive assessment of insulin sensitivity varied from two days to four weeks. The hyperinsulinaemic euglycaemic clamp technique was found to have a coefficient of repeatability of 0.85-1.0, which corresponds to an intraindividual coefficient of variation of 10 (Del Prato etal. 1986 Morris etal. 1997 Bokemark etal. 2000 Soop etal. 2000).

Stepped hyperinsulinaemic glucose clamp tests

In order to assess whole body glucose metabolism under conditions where more than one insulin dose is given during a single clamp experiment, a stepped hyperinsulinaemic glucose clamp test protocol can be applied (Basu etal. 2000 Bavenholm etal. 2001 Miyazaki etal. 2001 Anderwald etal. 2002). Because each step of hyperinsulinaemia needs at least 100 minutes to approximate steady state conditions, the total duration of the clamp experiment becomes a limiting factor. Two- or three-step hyperinsulinaemic glucose clamp tests are most commonly applied. In order to avoid carry over effects from the previous insulin infusion step, the experiments should be started with the lowest and end up with the highest insulin infusion rate. For example, the insulin infusion rates of a two-step hyperinsulinaemic glucose clamp test could be 40 mU-m-2-min-1 during the first and 160 mU-m-2-min-1 during the second step, whereby each step of the insulin infusion rate is maintained for at least 100 minutes....

Annexins And Diabetes

Diabetes is a chronic condition that can present in two different ways type-1 insulin-dependent diabetes or the more common type-2 insulin non-dependent diabetes. In both instances it is the resulting hyperglycemia that is thought to be primarily responsible for the disease facies. Although diabetes is a systemic condition that affects all parts of the body, for the purposes of this discussion the endothelium will be the main point of focus, since the most complete data regarding the role of annexins in diabetes have come from studies examining their actions in endothelial cells. There are thought to be four major effects of hyperglycemia on endothelial cells an increase in flux through the polyol pathway which leads to a depletion of NADPH and ultimately diminishes the cell's ability to produce protective anti-oxidants, an increase in conversion of glucosamine-6-phosphate to N-acetylglucosamine which leads to the formation of transcription factor-sugar adducts (which can affect...

Hypoglycaemic stimuli for research Insulin tolerance test

Most experimental hypoglycaemia is induced by insulin. An intravenous insulin challenge, called the insulin tolerance or insulin stress test, was the first test used to determine the effect of hypoglycaemia (Dell'acqua 1951 Hanzlicek & Knobloch 1951). This method was used in early studies that identified the role of the adrenal gland in protective responses to hypoglycaemia (Vogt 1951 De Pergola & Campiello 1953) and has also been used in the past to induce hypoglycaemic seizures as a treatment for severe depression (Mueller et al. 1969) and as a stimulus for gastric acid secretion in the standard Hollander test assessing the completeness of vagotomy (Colin-Jones & Himsworth 1970). It is still used to determine pituitary reserve for growth hormone and cortisol release. Prior to performing an insulin tolerance test, it is important to rule out complete deficiency of counterrgulatory hormones and establish cardiovascular status. A 9 am cortisol, baseline thyroid function and...

Intravenous insulin infusion test

The intravenous insulin infusion test has been used as a tool for identifying type 1 diabetes patients who are at increased risk of hypoglycaemia during intensive therapy. The presence of neurological symptoms of hypoglycaemia or further decline of plasma glucose to below 1.9mmol l after intravenous insulin (40mu kg h) were considered a sign of an inadequate counterregulatory response and increased risk of severe hypoglycaemia was predicted on the subsequent application of intensified insulin therapy (White et al. 1983). A similar protocol was used by Ryder et al. to show that severe hypoglycaemia and counterregulatory failure were more common in people with a history of severe hypogly-caemia and that those with classical autonomic neuropathy did not correspond (Abramson et al. 1966). Bolli and colleagues further modified the insulin tolerance test by suggesting that the subcutaneous route more closely mimicked the clinical situation (Bolli et al. 1985). Overall, the insulin tolerance...

Onestep hyperinsulinaemic hypoglycaemia clamp

In a one-step study, the infusions of insulin and glucose are initiated as describe above to maintain euglycaemia for a period of stabilisation and then the glucose infusion is reduced or stopped, causing the plasma glucose to drop to the predetermined level within a fixed time (Maran et al. 1991). These can be quick fall or slow fall depending on the relative rates of insulin and glucose. The glucose infusion is then restarted to maintain the hypoglycaemia at a fixed plasma glucose level for a fixed period of time. At the end of the study the glucose infusion is increased and the insulin stopped to restore euglycaemia.

Congenital Generalised Lipodystrophy Berardinelli Seip Syndrome or Lipoatrophic Diabetes

A patient with congenital lipodystrophy or lipoatrophic diabetes. There is evidence of a pronounced loss of subcutaneous fat, acromegaloid aspect, and phlebomegaly (for details, see Table 3, patient GF) Fig. 2. A patient with congenital lipodystrophy or lipoatrophic diabetes. There is evidence of a pronounced loss of subcutaneous fat, acromegaloid aspect, and phlebomegaly (for details, see Table 3, patient GF) plasma levels, hypertrichosis, mild virilisation, liver enlargement, reduced glucose tolerance or overt diabetes, heat intolerance, and increased perspiration (Table 2) 21-23 . Insulin resistance CGLD can manifest with different expression of signs and symptoms and with different degrees of severity of the metabolic abnormalities (Table 3). Insulin resistance usually evolves into overt diabetes. Micro- and macroangiopathies and keto-sis are unusual in lipoatrophic diabetes. An increased resting energy expenditure without abnormalities of thyroid function has been...

Cytokines and Insulin Resistance

In addition to their well-known anorectic and hypermetabolic effects, cytokines appear to be involved in obesity-related disorders such as insulin resistance and vascular diseases 65 . Epidemiological findings support the hypothesis that the metabolic syndrome, type II diabetes and cardiovascular diseases have an inflammatory component mediated by cytokines 66, 67 . Thus, overweight and obese children as well as adults TNF-a was among the first substances to be implicated in fat cell insulin resistance 68 . Adipose tissue TNF-a expression is increased in obese subjects, and TNF-a may limit an increase in adipocyte size by inhibiting lipoprotein lipase (LPL) and increasing insulin resistance 68 . A p55 TNF-a receptor-mediated phosphorylation of serine residues on the insulin receptor substrate-1 (IRS-1) appears to be an important mechanism for the induction of insulin resistance by TNF-a 69, 70 . The genetic deficiency of TNF-a or TNF-a signalling resulted in improved insulin...

HsCRP Metabolic Syndrome and Type 2 Diabetes Mellitus

Clinical practice, such as elevated triglycerides, low HDL-C, obesity, high fasting glucose, and high blood pressure (BP). In the Women's Health Study, e.g., after adjustment for multiple potential confounders, the RRs of incident hypertension for increasing hsCRP quintiles were 1.00 (referent), 1.07 (95 CI 0.95-1.20), 1.17 (95 CI 1.04-1.31), 1.30 (95 CI 1.17-1.45), and 1.52 (95 CI 1.36-1.69), respectively (p for trend of < 0.001) (73). hsCRP levels are also correlated with other components of the syndrome not easily assessed during routine office visits, such as fasting insulin, microalbuminuria, and impaired fibrinolysis. Indeed, among Women's Health Study participants without diabetes, hsCRP and BMI were the only independent correlates of fasting insulin level modeled as a continuous dependent variable. After adjustment for BMI and other risk factors for diabetes, the RR for elevated fasting insulin ( 51.6 pmol L) increased with the tertile of hsCRP (for hsCRP < 1.4, 1.4-4.4,...

Leptin Interacts with Ghrelin and Insulin

Leptin and insulin interact with each other. Insulin plays a major role in the regulation of lep-tin production, stimulating the transcriptional activity of the leptin promoter, increasing leptin gene expression and elevating leptin circulating concentrations. These effects are all mediated by actions of insulin to promote glucose uptake and oxidative metabolism in adipocytes 50 . On the other hand, leptin can down-modulate insulin signalling in adipocytes in two different ways. Leptin may modulate the pancreatic insulin and glucose homeostasis acting in the hypothalamus throughout the activation of neuronal circuits and the autonomic nervous system 49 , but it also exerts a direct effect on the adipocytes. In animals with elevated serum leptin concentrations, leptin inhibits insulin signalling, impairing insulin receptor autophosphorylation. This modulation of adipocyte insulin signalling could be relevant in physiological situations of hyperlepti-naemia and central leptin...

Monitoring Glycemic Control In Diabetic Patients

Our research with Hb variants clearly indicated that the same cIEF methodology used for the analysis of structural Hb variants could also be used for the analysis of posttranslational or chemically modified Hb variants. Post-translational hemoglobins include oxidation products (8) like methemoglo-bins and Hb A3 (glutathione adduct), and glycation products like Hb A1c. Adding additional tests to an existing platform and reagent system is attractive because of the potential for decreasing the instrument cost per test. Oxidation products, however, are only measured in a small number of specialized laboratories to help diagnose congenital methemoglobinemias, a class of disorders resulting in the oxidation of heme iron and decreased heme oxygen binding (2,4). However, many laboratories, including ours, measure Hb A1c as an indicator of the long-term glucose control in diabetic patients. The following is an initial report of our research and development of cIEF for the analysis of Hb A1c...

Insulinlike Growth Factor I Receptor

The Insulin-like Growth Factor-I Receptor (IGF-IR) is a member of the insulin receptor family of tyrosine kinases. This transmembrane-spanning protein is composed of two a- and two -subunits linked by disulfide bonds. While the a-subunits are extracellular, the -subunits span the plasma membrane and encompass an intracellular tyrosine kinase domain devoted to the initiation of several signal transduction cascades. Signaling through IGF-IR is initiated upon binding of the cognate ligand Insulin-like growth factor-I (IGF-I) or II (IGF-II) to the extracellular domain of the receptor. It is thought that this peptide-protein interaction induces a conformational change that results in auto-transphosphorylation of each -subunit at specific tyrosine residues within the intracellular kinase domain and outside the catalytic domain. Activation of the receptor triggers, through docking and or phosphorylation of several transduction molecules (e.g., IRS-1, IRS-2 or Shc), results in activation of...

Insulin and Diabetes Mellitus

Energy reservoirs in humans are built up and broken down in response to hormonal messages. Insulin is the principal hormonal messenger and has an anabolic effect. It is a major regulator of glycogen storage and its most important action is to enhance glycogen synthesis 2,3 . In the metabolism of fat, insulin inhibits lipolysis and induces the storage of triglycerides in adipose tissue 4 . Diabetes mellitus is a syndrome characterised by chronic hyperglycaemia and disturbances of carbohydrate, fat, and protein metabolism associated with absolute or relative deficiencies in insulin secretion and or insulin action. Diabetes mellitus has been classified into four groups type 1, type 2, other specific types, and gestational diabetes. Type 1 diabetes results from destruction of the beta-cells of the pancreas, usually leading to absolute insulin deficiency. There are two forms of type 1 diabetes, immune-mediated diabetes and idiopathic diabetes. Type 2 diabetes refers to individuals who have...

Protein Metabolism in Diabetes Mellitus

Animal and in vitro studies have shown that insulin inhibits muscle protein breakdown and enhances protein synthesis 16,17 . The results of studies performed in humans do not always agree with those conducted in vitro and in vivo in animals. In human studies, whole-body protein synthesis is estimated by measuring the nonoxidative disposal of branched-chain, essential amino acids during the primed constant infusion of 1-13C Leu or 1-14C Leu. Protein breakdown is usually estimated from the release into plasma of essential amino acids, such as leucine or phenylalanine, while net protein loss is determined from the irreversible loss of any essential amino acid that occurred by oxidation or hydroxylation. Increased rates of leucine flux were found in type 1 diabetic patients, indicating increased protein breakdown. Leucine oxidation also increased, suggesting increased net protein loss. In contrast, the rate of non-oxidised leucine disposal, i.e. the fraction of leucine entering protein,...

Malnutrition Related Pancreatic Diabetes Mellitus

In tropical countries, there is another type of diabetes with many atypical clinical features. Hugh-Jones, in Jamaica, described the features of this type of diabetes and named it type J diabetes 32 . The features of this type include early-age onset of diabetes, a lack of ketosis, a relatively large insulin requirement, and lean body. Although many variants have been reported, the common features of this type of diabetes are malnutrition and protein deficiency. In 1985, a World Health Organisation study group identified two main subgroups of pancreatic diabetes protein-deficient diabetes mellitus (PDDM), and fibrocalculous pancreatic diabetes (FCPD). In patients with the latter, there was no history of alcohol, biliary disease, or other known cause of pancreatitis. Clinically, malnutrition-related diabetes differs from chronic alcoholic pancreatitis in several respects. The disease occurs at an earlier age (usually before age 30) and is related to malnutrition, particularly in...

Characteristics of Routinely Administered Insulin Preparations

Common classes and examples of routinely administered insulin preparations that are often mixed on individual daily dosing schedules to permit the most precise therapeutic maintenance of euglycemia in Type (juvenile diabetes) and Type II (adult-onset diabetes) insulin-dependent diabetics. Class of Insulin Preparations

Defects of skeletal muscle glucose metabolism in insulin resistant states

Using the above mentioned methods, studies on skeletal muscle glycogen synthesis in insulin resistant populations revealed 60 decrease of insulin stimulated glycogen synthesis in overt T2DM patients (Shulman et al. 1990) (Figure 11.6) as well as 70 decrease in their lean insulin resistant offspring (Rothman et al. 1995). The same defect was found in obese non-diabetic insulin resistant volunteers (Petersen et al. 1998a). Further, defects in the insulin dependent phase of glycogen resynthesis that follows the depletion of glycogen stores by exhausting exercise were found in the insulin resistant offspring of T2DM patients (Price et al. 1996) decreased postprandial skeletal muscle glycogen synthesis in normal physiological conditions after a mixed meal was found in T2DM patients by the same method (Carey et al. 2003). Increase of glucose-6-phosphate concentration during hyperinsulinaemic-euglycaemic clamp is blunted according to the extent of insulin resistance in all insulin resistant...

Mitochondrial function in insulin resistant states

Shifting the focus down the metabolic pathways to the point where lipid and glucose oxidation meet in cell, it was hypothesised that mitochondrial oxidative and phosphorylation capacity might be a contributing factor to insulin resistance and increased intracellular lipid storage intramyocellular lipid (IMCL) content (Shulman 1999). One of the key intermediate metabolites of lipid oxidation long-chain acyl-CoA was found to be involved in the regulation of glycogen synthase (Wititsuwannakul & Kim 1977) and glucokinase (Tippett & Neet 1982) reactions and in the modulation of PCK isoforms (Faergeman & Knudsen 1997), and correlated with whole body insulin sensitivity (Ellis et al. 2000). In accordance with previous results, recent MRS studies have found that skeletal muscle mitochondrial oxidative and phosphorylation capacity is associated with a decrease of peripheral insulin sensitivity and an increas in intramyocellular lipid content in elderly sedentary individuals (Petersen...

Defects of hepatic glucose metabolism in diabetes mellitus

Turning our attention to hepatic glucose fluxes following a normal meal in type 1 and type 2 diabetic patients, studies have revealed significant alterations of hepatic glycogen storage (Figure 11.12), glycogen release and gluconeogenesis in both patient groups (Taylor et al.1996 Hundal et al. 2000 Bischof et al. 2001, 2002 Singhal et al. 2002 Krssak et al. 2004). A defect in hepatic glycogen storage was observed in glucokinase deficient maturity-onset diabetes of the young 2 (MODY-2) patients, in whom the impaired hepatic glucokinase activity is held responsible for a reduction in the contribution of glucose (the direct pathway) to hepatic glycogen synthesis (Velho et al. 1996). Lower glycogen synthesis (Bischof et al. 2001, 2002 Krssak et al. 2004) and unsatisfactory suppression of endogenous glucose production (Sinha et al. 2002 Krssak et al. 2004) contribute to postprandial hyperglycaemia in both pathologies. Increased gluconeogenesis is the key to postabsorptive hyperglycaemia in...

Classification of Diabetes Mellitus and the Metabolic Syndrome

In 2003, the American Diabetes Association (ADA) revised the etiologic classification of diabetes mellitus, removing the distinction between primary and secondary causes of diabetes15 (Table 1). The nomenclature now uses Arabic rather than Roman numerals to designate T1DM and T2DM. Terms such as insulin-dependent, non-insulin-dependent, juvenile-onset, maturity-onset, and adult-onset diabetes are eliminated. Thus, diabetes is now classified according to etiology and pathophysiology, without distinction as to age of onset or type of treatment. 6.19.2.1 Type 1 Diabetes Mellitus 6.19.2.1.1 Immune-mediated diabetes mellitus (Type 1A) Immune-mediated diabetes, previously referred to as insulin-dependent diabetes, type I diabetes, and juvenile-onset diabetes, accounts for 5-10 of all cases of diabetes. Immune-mediated diabetes typically develops in childhood and adolescence, but has a variable age of onset ranging from infancy to the eighth and ninth decades of life. Abnormalities in...

Pharmacodynamics and pharmacokinetics of insulin

Insulin was initially available as a soluble, clear solution. The relatively short duration of action meant that individuals had to take multiple daily injections. Combining insulin with protamine or high concentrations of zinc led to the formation of suspensions that are slowly absorbed with a longer and variable duration of action. Insulin analogs were designed with more predictable characteristics of rapid or attenuated absorption and action. The pharmacodynamic profiles of the different types of insulin and insulin analogs are summarized in Table 9. In solution, and in the b-cell where its concentration is high, insulin tends to self-associate, forming dimers, hexamers, and larger aggregates. In the b-cell, this self-association facilitates the transportation, conversion, and intracellular storage of insulin crystals. However, self-association retards absorption of soluble insulin after subcutaneous administration because hexamers must dissociate to monomers before entering the...

General principles of insulin therapy

The goal of insulin replacement therapy is to achieve a blood insulin profile that mimics physiologic insulin secretion. Basal insulin suppresses endogenous glucose production between meals and overnight and boluses of insulin are necessary with meals to promote postprandial glucose utilization. The type, frequency, and timing of insulin injections necessary to achieve this is greatly influenced by the amount of residual b-cell function and concurrent use of oral hypoglycemic agents. 6.19.6.5.4.1 Type 1 diabetes As b-cell function fails, individuals with T1DM require exogenous insulin for survival. Daily insulin requirements are usually between 0.5 and 1.0 units kg_ 1. During the early stages of T1DM, residual levels of endogenous insulin can reduce the daily insulin requirements below this range. Intensive insulin therapy, defined as > 3 insulin injections daily, provides more flexibility of lifestyle and often better glycemic control in individuals with T1DM than is achieved with...

Side effects of insulin

The most significant adverse effect of insulin therapy is hypoglycemia. This is especially the case for treatment of T1DM, but is also true for T2DM. Insulin allergy and lipoatrophy were commonly seen with the use of animal insulin before 'pure' and biosynthetic preparations became available. Both reactions are now rare, but can be seen, probably because there is some degradation during storage and or with depot injection into tissues that can induce an immune response. Weight gain commonly occurs following improved glycemic control with insulin therapy. In the UKPDS, individuals receiving insulin therapy had an average weight gain of 4.0 kg over the course of the study.81

Type 2 diabetes mellitus

Although the diagnosis of T2DM is straightforward, it is extremely difficult to monitor and to treat successfully long-term. Therapy and the monitoring of its effectiveness are complex, invasive, and expensive. Lack of patient education and resources compounds the problem and contributes to non-compliance and suboptimal glycemic control. The asymptomatic nature of chronic hyperglycemia does not allow the patient to truly understand the risk of diabetic complications until irreversible damage has developed. Therapies that have been added to available options in recent years have new and different mechanisms of action. However, when used as monotherapy, none of them (save insulin and its analogs) sustain optimal control for long intervals of time in the majority of patients.

Incretin Augmentation of Insulin Secretion

The observation that food ingestion or enteral glucose administration provoked a greater stimulation of insulin release than similar amounts of glucose infused intravenously led to the recognition of gastrointestinal hormones known as incretins. Although a number of neurotransmitters and gut hormones possess incretin-like activity, several lines of evidence (immunoneutralization, administration of antagonists, and knockout studies) suggest that glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) represent the dominant peptides responsible for nutrient-augmented stimulation of insulin secretion. Exenatide, the first GLP-1 agonist, has recently received FDA approval for adjuvant therapy in T2DM (see Section 6.19.6.7) Dipeptidyl peptidase-IV (DPP-IV) is a membrane-associated peptidase that is widely distributed in tissues and also exists as a soluble circulating form. Several DPP-IV inhibitors have been characterized and shown to lower blood glucose via...

Alternative Methods of Insulin Delivery

Delivery of insulin via the pulmonary route can potentially provide the benefits of bolus insulin therapy without injections. Pulmonary delivery of insulin uses the well-vascularized, highly permeable alveoli of the lungs as the port of entry for macromolecules. Several formulations of inhaled insulin are in clinical trials or awaiting regulatory approval. Skyler et al.93 provided the proof-of-concept study that illustrates the efficacy of mealtime use of inhaled insulin in individuals with T1DM. Glycemic control was similar in subjects receiving preprandial inhaled insulin plus subcutaneous ultralente insulin at bedtime (HbA1C 7.9 at 12 weeks) or a usual insulin regimen of two to three injections per day (HbA1C 7.7 ). Similarly, Cefalu et al 4 showed similar efficacy of inhaled insulin in individuals with T2DM whose treatment with combination oral agents had failed. In both these studies inhaled insulin was well tolerated without adverse pulmonary effects. However, due to its...

Body fat distribution and insulin resistance Skeletal muscle intramyocellular lipids

Overabundance of plasma triglycerides and free fatty acids entering the circulation by lipol-ysis from adipose tissue or by ingestion from food is frequently associated with pathophys-iology of insulin resistance and diabetes mellitus (Defronzo 2004). Results of radioactive tracer and stable isotope dilution studies have suggested that both hepatic and peripheral muscle tissues are involved in the development of insulin resistance (Defronzo 1988). Focusing on glucose uptake in skeletal muscle, based on the results of his experimental studies series, Sir Randle (Randle et al. 1963) postulated the hypothesis that the substrate competition for mitochondrial oxidation is the major mechanism involved in the impairment of glucose uptake into skeletal muscle. Recent studies applying 13C and 31P MRS methods (reviewed in Chapter 11 of this book) and analysis of skeletal muscle biopsy have shown that direct impairment of insulin signalling cascade (Griffin et al. 1999), and therefore direct...

Application of muscle biopsy in diabetes

Insulin resistance in skeletal muscle is a major hallmark of type 2 diabetes (Beck-Nielsen & Groop 1994 Beck-Nielsen 1998 Beck-Nielsen et al. 2003). During the past two decades, skeletal muscle biopsies have been increasingly applied in the search for biochemical and molecular abnormalities responsible for insulin resistance. It is evident that type 2 diabetes is caused by a complex interplay between genetic and environmental factors. The latter include intrauterine malnutrition and postnatal factors such as obesity, physical inactivity and modern Western lifestyle, as well as the metabolic milieu associated with type 2 diabetes and prediabetes, including glucose intolerance, hyperglycaemia, hyperlipidaemia and hyperinsulinaemia (Beck-Nielsen & Groop 1994 Beck-Nielsen 1998 Beck-Nielsen et al. 2003). The choice of study design is therefore extremely important for the interpretation of data obtained (Table 14.1). Novel potential markers of insulin resistance and type 2 diabetes...

Application of muscle morphology in type 2 diabetes

Insulin resistance and type 2 diabetes are associated with a number of morphological characteristics in skeletal muscle. In humans, muscle fibre composition is more mixed than in rodents (Johnson et al. 1973). This has implications for many biochemical and metabolic abnormalities observed in studies of crude muscle extracts, as the functional and metabolic properties of muscle are to a large extent determined by its fibre type composition. Using the In most (Marin et al. 1994 Gaster et al. 2001) but not all (Zierath et al. 1996) studies, a lower proportion of type 1 muscle fibres and a higher proportion of type 2 (particularly 2b) muscle fibres have been reported in type 2 diabetes. Furthermore, histochemical studies have shown a lower capillary density in skeletal muscle in type 2 diabetes (Marin et al. 1994). Using electron microscopy and stereology we have found an increased intramyocellular lipid content (IMCL) and a lower muscle glycogen content in type 2 diabetes (Levin et al....

Application of myotubes in diabetes research

In human myotubes established from skeletal muscle biopsies of both healthy subjects and patients with type 2 diabetes, we have used a variety of approaches to study possible mediators of insulin resistance under both physiological and so-called 'inducing' conditions (Table 14.2). This includes biochemical determination of 1) glucose, G6P, glycogen and triacylglycerol (TAG) (Gaster et al. 2001c, 2002, 2004 Kase et al. 2005) 2) activity, kinetics and or protein expression of distal components of the insulin signaling cascade such as GS and GSK-3 (Gaster et al. 2001c, 2002, 2004) and 3) other enzymes essential for glucose and lipid metabolism such as hexokinase (HK), citrate synthase (CS), CK and 3-hydroxy-acyl-CoA dehydrogenase (HAD) (Gaster et al. 2001a,b Ortenblad et al. 2005) as well as 4) gene expression analysis in myotubes using both the cDNA microarray technique and real time (RT)-PCR reactions (Hansen et al. 2004 Abdallah et al. 2005 Kase et al. 2005). Moreover, we have...

Major data and relevance to better understanding of diabetes and metabolism

Several studies in diabetic patients revealed the effects of lifestyle modification or physical exercise on endothelial function. In insulin-resistant subjects, lifestyle modification with exercise and weight reduction over six months improved endothelial function (Hamdy et al. 2003). Interestingly, the relationship between percentage weight reduction and improved FMD was linear. A similar result was seen in patients with type 2 diabetes (Maiorana et al. 2001). Likewise, in patients with type 1 diabetes, FMD could be improved by four months of bicycle exercise (Fuchsjager-Mayrl et al. 2002). However, the positive training effect on endothelial function was not maintained after cessation of regular exercise (Figure 15.5). In all studies, GTN-mediated dilation was unaffected by exercise. Another interesting study assessing FMD in 75 children with type 1 diabetes revealed that even children with diabetes have impaired endothelial function compared to healthy controls (Jarvisalo et al....

CASE 2 Latent Autoimmune Diabetes In Adults Case Description

This fit, 75-yr-old male flight engineer was initially diagnosed with type 2 diabetes mellitus at the age of 73. At the time of diagnosis in November 1997, he was hospitalized with a deep-seated staphylococcus aureus infection following arthroscopic left rotator cuff repair. He was initially treated with insulin at the time of diagnosis, but later was switched to the combination of metformin and troglitazone by his primary physician. With failure of these agents to provide adequate glycemic control, in June 1999 he was started on insulin. At the time of referral, he was taking NPH, 10 U q AM and 10 U q PM and Rosiglitazone 4 mg daily (added 2 wk prior to presentation and subsequently discontinued). His family history was significant for his mother having type 2 diabetes mellitus, and dying at age 82 of cardiovascular complications. There was no family history of type 1 diabetes mellitus. Because his presentation was somewhat atypical for type 2 diabetes mellitus, the decision was made...

CASE 3 Changing Insulin Regimen Case Description

This 44-yr-old man was diagnosed with type 1 diabetes mellitus at the age of 27, when he presented with weight loss, frequent urination, and increased appetite. He was started on insulin at the time of diagnosis. There was no family history of diabetes mellitus. His only concomitant medical problem is hyperlipidemia. He has no history of background diabetic retinopathy (yearly ophthalmology visits dating back to 1983) or diabetic nephropathy. Three years and 11 mo following the diagnosis of type 1 diabetes mellitus, he was enrolled in the Diabetes Control and Complications Trial (DCCT). In the DCCT, he was randomized to the experimental arm of the trial that included beginning an intensive insulin regimen of three shots of regular insulin and one shot of ultralente each day. (multiple daily injection MDI program). At entry into the DCCT (March 1987), his hemoglobin A1c (HbA1c) was 7.8 (normal range 4.0-6.3 ). Despite randomization to the intensive insulin regimen, his HbA1c at the...

Major data relevance to better understanding of diabetes and metabolism

One of the advantages of IMT measurements is that they can be performed quickly and easily by an experienced observer. Thus, large trials can be performed. IMT measurements are suitable for assessing the incidence of early stages of atherosclerosis in patients with diabetes. Accordingly, in a smaller study including 229 patients with type 2 diabetes, IMT was shown to be an independent predictor of cardiovascular events (Bernard et al. 2005). The odds ratio for cardiovascular events per SD increase in carotid IMT was 1.63 (95 CI 1.01-2.63). In contrast to the methods that estimate endothelial function, described above, IMT assesses a more advanced stage of atherosclerosis, in which structural changes of the vascular wall are already demonstrable. Nevertheless, therapeutic intervention studies have shown that enhanced IMT is at least partially reversible in patients with diabetes. An example for such an intervention study is that by Langenfeld et al. (2005) in patients with type 2...

Micronutrients Diabetes

To enhance the action of insulin and help control blood glucose Can enhance insulin sensitivity and reduce needs for oral hypoglycemics and or insulin.5-7 Reduces platelet aggregation and risk of thrombosis As a component of GTF, helps control blood glucose and decrease need for insulin or hypoglycemic drugs.1-3 Can be taken together with 5-10 g brewer's yeast Magnesium deficiency is common in diabetes. Supplements may help control blood glucose and protect against cardiovascular disease11 Helps replenish urinary losses To help control newly-diagnosed type 1 diabetes Niacinamide 1-3 g begin with 500 mg day Supplements in newly diagnosed type 1 diabetes can reduce insulin requirements and extend the time before beginning insulin.15 Avoid nicotinic acid, anotherform of niacin, which can be harmful in diabetics

Protein Kinase B and the Glucose Transporter How Insulin Works

Figure 16.10 shows the insulin receptor. Like other receptor tyrosine kinases, the insulin receptor has an extracellular domain that can bind the transmitter, in this case the protein insulin, a single polypeptide chain that crosses the plasma membrane, and a cytosolic domain with tyrosine kinase activity. Unlike growth factor receptors, the insulin receptor exists as a dimer even in the absence of its ligand, insulin. When insulin binds, the shape and orientation of the individual insulin receptors change a little, and this allows each receptor to phosphorylate its partner upon tyrosine. An associated protein called the insulin receptor substrate number 1 (IRS-1) is also phosphorylated on tyrosine. Proteins with SH2 domains are therefore recruited, either to the phosphorylated tyrosines on the insulin receptors themselves or to the phosphorylated tyrosines on IRS-1. The most important protein to be recruited is phosphoinositide 3-kinase (PI 3-kinase). Binding to the phosphorylated...

Using E coli to make insulin

It helps move sugars and starches from the bloodstream into the cells, where they can be used for energy. People who have a disease called diabetes either do not make enough insulin or do not use it properly. They need to take insulin every day to keep their blood sugar levels under control. In the past, people with diabetes were often given insulin that was taken from animals. But sometimes their immune systems would recognize this insulin as foreign, leading to an immune reaction. In the late 1970s, scientists began using E. coli to produce insulin. The bacteria can produce recombinant insulin in large amounts. Because recombinant insulin is identical to human insulin, it does not cause an immune reaction in people who take it.

Patients with Diabetes

Marshall Wynngarden, a 34-year-old physician, came to Johns Hopkins in 1986, with a history of insulin-dependent diabetes since age 9 and renal failure since 1983. He was complaining of fatigue, arthritic pains, sexual dysfunction, and muscle cramps. Despite an ACE inhibitor and moderate protein restriction, his kidney function declined. In 1988 he was started on a very-low-protein diet, supplemented by amino acids alternating with ketoacids. Symptoms improved, but he continued to have difficulty with control of his diabetes. Kidney function continued to decline slowly, and he finally decided to start dialysis in 1992, after four years.

Type 1 Diabetes Mellitus

Type 1 diabetes mellitus, previously called insulin-dependent diabetes mellitus, is a multisystem metabolic disease resulting from impaired insulin production that affects about 0.2 of the U.S. population, with a peak age at onset of 11 to 12 years, and the incidence is increasing. The disease is characterized by hyperglycemia and ketoacidosis. Chronic complications of type 1 diabetes include progressive atherosclerosis of arteries, which can lead to ischemic necrosis of limbs and internal organs, and microvascular obstruction causing damage to the retina, renal glomeruli, and peripheral nerves. These patients have a deficiency of insulin resulting from immune-mediated destruction of the insulin-producing P cells of the islets of Langerhans in the pancreas, and continuous hormone replacement therapy is needed.

Insulinlike Growth Factors

The discovery of IGFs came about from a variety of approaches but initially from the identification of insulin-like activities in plasma or serum. At first these activities had various names such as nonsuppressible insulin-like activities, A group of polypeptides present in plasma that have insulin-like activity but could not be neutralized by antibodies directed against insulin, called the nonsuppressible insulin-like activities (NSILA), were separated into two fractions NSILA-P, which was precipitable by ethanol at low pH, and NSILA-S, which was soluble under these conditions. Two peptides of about 7000 MW with mitogenic activity were isolated from the NSILA-S fraction.195 These have now been called insulin-like growth factors 1 and 2 (IGF-1 and IGF-2).

Calpain 10 and type 2 diabetes

In the first successful genome-wide scan of a complex disease like type 2 diabetes, Graeme Bell and co-workers reported significant linkage (LOD 4.1 p < 10-4) between type 2 diabetes in Mexican American sib pairs and a locus on chromosome 2q37, called NIDDM1 (Hanis et al. 1996). Still, this region was quite large (12 cM), encompassing a large number of putative genes. A re-examination of the data suggested an interaction (epistasis) with another locus on chromosome 15 (with a nominal LOD of 1.5). This enabled the researchers to narrow the region down to 7cM. Luckily, because it is telomeric with a high recombination rate, the 7cM genetic map only represents 1.7 megabases of physical DNA. To clone the underlying gene, they genotyped 21 SNPs in this 7 cM interval and identified a three-marker haplotype that was nominally associated with type 2 diabetes. At the end, three intronic SNPs (43,44 and 63) in the gene encoding for calpain 10 (CAPN10) could explain most of the linkage...

The Diabetes Simulating Model

A hypothetical medical condition was constructed to roughly resemble type 1 (juvenile) diabetes a condition that arises in childhood in which the body becomes unable to generate insulin, leading to sugar imbalances. People with type 1 diabetes can encounter a range of serious, ultimately life-threatening complications. Stem cell therapy appears to be effective for the treatment of type 1 diabetes. An important potential benefit of stem cell therapy is a reduction in mortality for individuals with this condition. To quantify its possible effect, an example survival curve was designed for type 1 diabetes. For simplicity, it was assumed that there are 1000 new cases diagnosed among children per year, and that these diagnoses occur among children at age 10. The survival curves were designed, beginning with the US population mortality rates by age for 2001, assuming that mortality rates for the simulated condition are seven times higher than that for the overall population (Fig. 2). This...

Growth Hormone and Insulin Like Growth Factor1

Growth hormone (GH) and insulin-like growth factor (IGF)-1 stimulate amino-acid uptake and protein synthesis in muscle and improve myocyte proliferation and differentiation in animal studies 106, 107 . The FDA recently granted accelerated approval for a form of recombinant human GH (rhGH) to treat AIDS wasting. Preliminary reports from Schambelan and co-workers in AIDS patients have all been positive 108-112 . The combined GH and IGF-1 doses used in studies in adult males with HIV-associated weight loss had mixed results in producing a sustained anabolic response 113-120 . In fact, after trauma, the anti-catabolic action of rhGH is associated with a potentially harmful decrease in muscle glutamine production and increased mortality 116 . Use of the rhGH for elderly patients with a low somatomedin C or IGF improved lean muscle mass, but not functional ability. Moreover, frequent side effects were seen 121 . Morley and coworkers 122 demonstrated that rhGH, which is a very expensive...

Energy Expenditure in Diabetes Mellitus

Urinary glucose loss may be a more important cause of negative energy balance and weight loss in diabetic patients. However, the basal metabolic rate (BMR) of diabetic patients without glycosuria is higher than that of normal subjects. Increased resting energy expenditure may be another mechanism contributing to weight loss in diabetic subjects, in addition to caloric losses due to glyco-suria. The basal energy expenditure of type 1 diabetic patients (2042 Kcal 24 h) was found to be significantly higher than that of control subjects (1774 Kcal 24 h), and intravenous insulin treatment significantly reduced energy expenditure to 1728 Kcal 24 h, which matched predicted values 7 . The basal energy expenditure of obese subjects with type 2 diabetes was also found to be higher than that of obese subjects with normal glucose tolerance. The mean resting metabolic rate (RMR) of diabetic subjects (32.9 Kcal day kg fat-free mass) was 5 higher than that of nondiabetic subjects (31.4 Kcal day kg...

Inulin and Diabetes Mellitus

Diabetes mellitus is a disease in which blood sugar is not properly taken up into cells. Thus, the level of glucose in the blood remains high. The uptake of glucose into the body's cells is controlled by the hormone insulin, which is produced by the pancreas. Type 1 diabetes is due to the pancreas failing to produce sufficient insulin. It is often caused by genetic factors. Non-insulin-dependent diabetes, or type 2 diabetes, occurs when the body's cells are unable to respond very efficiently to the insulin produced. It is associated with obesity, overnutrition, excess dietary fat and sugar, and other factors. Type 2 diabetes accounts for around 90 of all diabetes. Both types of diabetes are treated by the injection of insulin, which acts to reduce the blood glucose concentration by facilitating the uptake of glucose by the cells in type 1 diabetes, and by supplementing the body's insulin in type 2 diabetes. Over 18 million adults in the U.S. have diabetes (CDC, 2006), and over 170...

Changing the Fate of Diabetics in the Dialysis Unit

In a symposium on diseases of kidney reported in 1971 Williem J. Kolff was quoted as saying in 1938, 'Gradually the idea grew in me that if we could only remove 20 g of urea and other retention products per day we might relieve this man's nausea and that if we did this from day to day, life might still be possible' 8 . Dunea 8 started his article after this statement and wrote, 'Within three decades dialysis has revolutionized the field of nephrology and opened new vistas in the treatment of uremia. Yet, dialysis gradually outgrew its difficult beginnings and became established among the great medical achievements of our age.' In this article there is no mention of the diabetic ESRD patient. A year later in 1972, Ghavamian et al. 9 report on 9 patients with renal failure resulting from DN who were treated by hemodialysis. The average duration of diabetes was 21 years and the average duration of nephropathy was 26 months. One patient survived for more than 3 years. The others survived...

Acquired Generalised Lipodystrophy Lipoatrophic Diabetes or Lawrence Syndrome

Acquired generalised lipodystrophy (AGLD) is a rare, juvenile-onset lipodystrophy, first fully described by Lawrence in 1946 1 , who reported on a young female subject with 'lipodystrophy, and hepatomegaly with diabetes, lipaemia and other metabolic disturbances.' To date, approximately 80 patients with AGLD have been reported 2 . Like others LDs, AGLD is prevalent in females. Lipoatrophy develops over a number of years, in childhood or in adolescence, so that the onset of the condition is later than that of congenital generalised lipodystrophy (CGLD). Extended areas of subcutaneous fat are involved, including the face, arms, and legs. Less frequently mesenteric, retroperitoneal, perirenal and mediastinal fat depots are involved, while retroorbital fat seems to be spared. Muscle mass, evaluated by dual energy X-ray analysis (DEXA), is preserved or even increased compared to age-, sex- and body mass index (BMI)-matched subjects. Therefore, in spite of the generalised atrophy of fat...

CASE 4 Progressive Diabetic Nephropathy Case Description

This 39-yr-old woman was diagnosed with type 1 diabetes mellitus at the age of 7 yr, during an evaluation for chicken pox. Presenting symptoms included weight loss and frequent urination and was found to be in ketoacidosis. Complications from diabetes at present include neuropathy, nephropathy, and proliferative retinopathy. Her only other medical problem is hypertension. During this time, the patient was changed from a one injection daily insulin regimen to a two injection daily lente program. Despite this change, her hyperglycemia persisted, and her physician added regular insulin (LR-0-LR-0 program). In 1983, she was started on

Insulin infusion

The goal of the insulin infusion is to acutely raise and maintain the plasma insulin concentration at a new hyperinsulinaemic plateau for the duration of the clamp experiment. The insulin infusion rate applied depends on the desired steady state plasma insulin concentration during the clamp. In the original experiments reported by Sherwin etal. (1974) and De Fronzo etal. (1979), plasma insulin concentrations were raised to approximately 100 U ml above fasting levels by applying a continuous insulin infusion rate of 1 mU per kg bodyweight per minute or 40 mU-per square metre body surface area per minute, respectively. Since then, various insulin infusion rates have been applied during glucose clamp tests. However, one should be aware that when plasma insulin concentrations are raised above 500 U ml (corresponding to an insulin infusion rate of 200 mU-m-2-min-1), the physiological clearance mechanism of plasma insulin is saturated and plasma insulin concentrations will continuously...

Insulin resistance

Both type 1 and type 2 diabetics may be characterized by some degree of insulin resistance, but this may in fact be unrelated to microalbuminuria 1 . For example, in some studies in type 2 diabetes, no difference has been found in characteristic parameters related to insulin resistance - e.g. using the euglycaemic insulin clamp technique. Most studies are rather small and it seems unlikely that the measurement of insulin resistance will ever become useful in the prediction of diabetic renal disease or in the prediction of any complications related to diabetes, although insulin resistance may be related to blood pressure elevation and dyslipidaemia. It remains much more useful to focus on the direct and careful monitoring of blood pressure and lipid abnormalities, which are key elements of the insulin resistance syndrome 111-114 .

The insulin infusate

Where insulin is to be infused over prolonged periods, it is important to be sure that the concentration of the infusate remains stable. The dose is often estimated in milliunits of insulin per kilogram body weight, although using the body surface area is preferable, especially where subjects of different sizes are to be compared. Body surface area relates more precisely to volume of distribution. The specific requirements for individual studies are discussed below. Insulin sticks to plastic and so an insulin infusate will lose strength over time. To avoid this it is usual to make the insulin up in a 4 solution of autologous blood, and it is critical that the insulin is mixed by slow rotation (to avoid bubbling). The solution is then run through the entire giving apparatus, to saturate the binding sites in the plastic from the beginning. For infusions lasting more than five hours, fresh solutions should be made. A small amount of all infusions should be kept for later estimation of...

Diabetes

Insulin-Dependent Diabetes Mellitus Ninety-four subjects (45 men, 49 women) with insulin-dependent diabetes mellitus underwent bone density measurements of the PA spine and proximal femur with DXA (Hologic QDR-1000) (34). The subjects ranged in age from 20 to 56 years with a mean age of 30 years. Disease duration ranged from 1 to 35 years. Diabetic patients had reduced BMD at all sites in comparison to age- and sex-matched controls. Z-scores were -0.89 for the spine, -0.99 for the femoral neck, -1.05 for Ward's. Of these subjects, 19.1 met WHO diagnostic criteria for osteoporosis. The presence and severity of diabetic complications was associated with lower BMD. Noninsulin-Dependent Diabetes Mellitus (NIDDM) Hyperinsulinemia has been postulated to be an osteogenic factor. In a study of 411 men and 559 women aged 50 to 89 who were not diabetic by history or oral glucose tolerance test, BMD was measured in the lumbar spine and proximal femur using DXA (Hologic QDR-1000) and in the...

Diabetes Mellitus

Patients with diabetes have an increased incidence of CHD, hypertension, and heart failure (203,204), which is in part induced by the metabolic and structural changes seen in the diabetic heart. The diabetes-induced structural changes in the myocardium consist of increased fibrosis and increased ventricular mass (205,206), conditions that together with the more aggressive atherosclerosis may explain the higher cardiac morbidity and mortality in patients with diabetes. Both type 1 and 2 diabetes have been associated with increased levels of natriuretic peptides (207-210). Contrasting population-based data suggest that diabetes is associated with lower natriuretic peptide concentration (108), independent ofthe effect of obesity (108). However, in experimental animal models, diabetes increases the expression of cardiac BNP (211) and prevents myocardial growth via a cGMP-dependent mechanism (212). In humans, acute (i.e., lasting for hours) hyper-insulinemia causes an increase in ANP, but...

Insulin

The essential role of insulin in the treatment of T1DM is universally accepted, whereas its use in T2DM is often considered the last resort. Insulin should be viewed as a valuable therapeutic tool for early intervention, to attain and maintain target levels of glycemic control. The evolution of insulin preparations, from those 'purified' from animal pancreases, to human-insulin produced with recombinant DNA technology, and the present use of insulin analogs, represents more than 80 years of collaboration among industry, clinical, and basic research, and millions of people with diabetes.

Sources of insulin

With the availability of human insulin, use of animal insulin declined dramatically. Currently, the biosynthesis of human insulin involves insertion of the human proinsulin gene into either Saccharomyces cerevisiae (baker's yeast) or a nonpathogenic laboratory strain of Escherichia coli, which serve as the production organism. Human insulin is then isolated and purified. Sophisticated knowledge of the structure-function aspects of insulin has led to the development and production of analogs to human insulin. The molecular structure of insulin has been modified slightly to alter the pharmacokinetic properties of insulin, primarily affecting absorption from subcutaneous tissue. The B26-B30 region of the insulin molecule is not critical for insulin receptor recognition and it is in this region that amino acids have been substituted74 (Figure 8). Thus, the insulin analogs are recognized by the insulin receptor and bind to the receptor with similar affinity as native insulin. Insulin lispro

Types of insulin

Human insulin is available in rapid, short, intermediate, and long-acting forms (regular, NPH, lente, and ultralente). In addition, five insulin analogs are currently available for clinical use (insulins aspart, lispro, glulisine, detemir, and glargine). 6.19.6.5.3.1 Rapid-acting insulin analogs (lispro, aspart, and glulisine) Changes in the amino acid sequence of the insulin analogs lispro, aspart, and glulisine reduce the tendency to self-associate into hexamers, resulting in more rapid onset and a shorter duration of action compared to regular human insulin. Insulin lispro (Humalog) has a reversal of amino acid sequence at the B28 (proline) and B29 (lysine) positions, resulting in insulin lysine-proline. Insulin aspart (Novolog) has a B28 amino acid proline substitution with aspartic acid. Insulin glulisine (Apidra) has two amino acid substitutions and differs from human insulin in that B3 asparagine is replaced by lysine, and B29 lysine is replaced by glutamic acid.78 Table 9...

Diet Diabetes

The best way to prevent type 2 diabetes is to avoid gaining weight. Overweight people are four times more likely to develop type 2 diabetes than those who maintain normal body weight. Overweight diabetic patients can often reduce their need for drugs and control their blood sugar by weight loss. The glucose tolerance factor (GTF) is a naturally occuring compound that helps regulate blood sugar. It is found in rich amounts in brewer's yeast. Chromium is an essential component of GTF, and diets deficient in chromium produce glucose intolerance (see Fig. 5.11 ).1-3 Diabetics who excrete glucose in their urine have increased urinary loss of minerals (such as magnesium, zinc, and chro mium). Deficiencies of these important minerals further impair the ability to control blood glucose. Therefore, diabetic diets should emphasize foods rich in these minerals. The best diet for most diabetics is one low in refined sugars and high in complex carbohydrates and fiber (which slow absorption of...

Diabetes Insipidus

Diabetes insipidus is a rare complication of AML.57 Patients present with polyuria, polydipsia, and a low-serum antidiuretic hormone (ADH) level.58 Cytogenetic abnormalities associated with cases in the literature include monosomy 7, deletions of chromosome 7, and chromosome 3 abnormalities.5759 The reason for these specific associations is unknown.57 However, the proposed mechanism involves leukemic infiltration of the neurohypophysis. Magnetic resonance imaging (MRI) demonstrates a bright spot in the neurohypophysis prior to treatment.59 Both MRI findings and ADH release subsequently resolve after chemotherapy.59

Endogenous glucose output and rates of whole body glucose utilisation

Under several metabolic conditions endogenous glucose output is not zero during eugly-caemic clamp tests with plasma insulin concentrations within the physiological range (Rizza etal. 1982 DeFronzo etal. 1985 Campbell etal. 1988 Staehr etal. 2001 Bajaj etal. 2002 Seppala-Lindroos etal. 2002 Butler etal. 1990). In these cases the glucose infusion rates do not reflect whole body glucose metabolism because the residual endogenous output remains unaccounted for. This implies that as long as complete inhibition of endogenous glucose output is not guaranteed, the M value from a clamp experiment should not be taken as a measure of whole body glucose metabolism. If endogenous glucose output is erroneously assumed null, insulin stimulated rates of whole body glucose metabolism are underestimated. Thus, determination of endogenous glucose output is a necessity when plasma insulin concentrations are within the physiological range during a euglycaemic clamp test. In particular, the assessment of...

Technical requirements

In order to perform a glucose clamp test, several technical requirements must be met. Two intravenous lines must be kept patent for the duration of the clamp test, one for the infusion of glucose and insulin and the other for frequent blood sampling of arterialised blood. In Insulin induced vasodilatation

Blood sampling site arterial venous or arterialised venous blood sampling

The concentration of plasma glucose physiologically declines during the perfusion of glucose utilising tissues. In addition, pancreatic insulin secretion is regulated by the arterial blood glucose concentration. Early studies applying the glucose clamp technique measured the glucose concentration in arterial plasma drawn from a catheter in the brachial artery (Sherwin etal. 1974 Insel etal. 1975 DeFronzo etal. 1979). In subsequent insulin and glucose clamp studies, several investigators measured glucose concentration in venous plasma, which rendered arterial catheterisation unnecessary and simplified the protocol (Kraegen etal. 1983 Howard etal. 1984 Yki-Jarvinen & Koivisto 1984). However, the comparison of individuals at equivalent venous plasma glucose concentrations and matched insulinemia results in a systematic error when their sensitivity to insulin is not the same (Bergman etal. 1985). The arteriovenous balance technique demonstrates that the glucose concentration in venous...

Blood sampling schedule

Blood samples for the determination of glucoregulatory hormones should be drawn before the start of the clamp test and frequently during the final period of the clamp experiment. Many investigators perform blood drawings for the determination of plasma insulin concentration at 10 minute intervals during the final hour of the clamp experiment. This allows one to prove the assumption of steady state hyperinsulinaemia during the period when glucose infusions rates are used to compute the M value.

Nomenclature of glycaemic targets of clamp tests

In healthy subjects an insulin clamp performed at fasting plasma glucose concentration is termed an euglycaemic insulin clamp test. In general, when the target of plasma glucose concentration is above the fasting level, this is termed a hyperglycaemic insulin clamp test. The latter should not be mixed up with the hyperglycaemic glucose clamp test, which is performed without concomitant infusion of insulin and which can be used to assess endogenous insulin secretion in response to glucose (DeFronzo etal. 1979). In diabetic subjects exhibiting fasting hyperglycaemia, insulin clamps may also be performed at the individual fasting plasma glucose concentration, which is termed an isoglycaemic insulin clamp test. However, clamping plasma glucose at 90 or 100 mg dl in patients with diabetes mellitus is termed an euglycaemic insulin clamp test. Glucose clamp tests with the target of glucose concentration at or below 60 mg dl are termed hypoglycaemic insulin clamp tests (DeFronzo &...

Pancreatic clamp tests

In order to achieve a maximal possible suppression of endogenous insulin, glucagon and growth hormone release during hyperinsulinaemic clamp tests, a concomitant infusion of somatostatin can be applied (Gottesman etal. 1982 Best etal. 1983 Basu etal. 2000). Glucose clamp tests applying an infusion of somatostatin are commonly referred to as pancreatic clamp tests. Most investigators start the somatostatin infusion a few minutes before or simultaneously with the start of the insulin infusion. The infusion rates of somatostatin vary largely throughout the literature, ranging from 250 g per hour (Gottesman etal. 1982 Hawkins etal. 2002) to 360 g per hour (Henriksen etal. 2000) to 0.1 g-kg-1-min-1 (Krssak etal. 2004). One frequently reported side effect of high dose somatostatin infusions is abdominal discomfort. The use of somatostatin can be advantageous when stimulation of endogenous insulin secretion by substrates or pharmacological agents is to be minimised. One should be aware that...

Hypoglycaemia questionnaires

In hypoglycaemia research, it may be important to document the quality as well as the quantity of hypoglycaemia. Problematic hypoglycaemia may be described in terms of the frequency of severe hypoglycaemia and there are at least three validated questionnaire-based assessments of subjective awareness of hypoglycaemia. Clarke's questionnaire is a set of questions aiming at self-assessment of hypoglycaemia awareness. A scoring system stratifies the individual as having impaired awareness or being unaware (Clarke et al. 1995). Gold's assessment of hypoglycaemia awareness is based on no subjective change in hypoglycaemia warning symptoms since commencing insulin and the experience of mainly autonomic hypo-glycaemia symptoms, using a visual analogue scale of 1 to 7 for assessment of autonomic,

Continuous glucose monitoring CGMS

There has been some recent work to suggest that in patients with type 1 diabetes, interstitial glucose closely parallels blood glucose during hypoglycaemia (Caplin et al. 2003) and there are emerging data suggesting that glucose values obtained from continuous glucose monitoring devices are accurate during symptomatic hypoglycaemia (Choudhary et al. 2006).

Investigating the pathogenesis of problematic hypoglycaemia

For comparative studies, subjects should be age and gender matched, as there are important differences in counterregulatory responses between sexes and age groups (Matyka et al. 1997 Davis et al. 2000). Mixing genders and ages will at the very least increase the variance of the measures made and may obscure differences resulting from other factors. If groups are of mixed gender in a cross sectional study, the gender distribution must be matched. Vigorous exercise and caffeine should be avoided prior to the study as they can also affect counterregulatory responses (Debrah et al. 1996 Sandoval et al. 2006). Subjects should be studied in the same position (lying or standing) as there is a greater perception of hypoglycaemic symptoms in the standing position than in the lying position (Hirsch et al. 1991). It is usual to study subjects in the fasting or post-absorptive state. This allows a steady-state baseline. In the fed state, symptoms of hypoglycaemia are decreased, but...

The nature of the glucose sample

For prolonged studies, most authorities use plasma rather than venous blood. This necessitates rapid bedside spinning of the sample in a microfuge and sampling of the plasma. Plasma glucose is unaffected by haematocrit and reflects the glucose cells are seeing. For the same reason, the ideal sample would be arterial blood, as this will reflect the glucose that the tissues, particularly the brain, are receiving. Furthermore, muscle is an active tissue that will remove glucose (especially if insulin stimulated and insulin sensitive) and add noradrenaline, for example, to blood. There is thus a significant arterio-venous difference for several substrates, which will vary according to the degree of insulinisation, insulin sensitivity and degree of hypoglycaemia (Liu et al. 1992). Because of the increased risk of arterial cannulation, most authorities use arterialised venous blood where possible. To arterialise venous blood, the cannula is placed in a vein draining a minimally active...

Sulphonylurea induced hypoglycaemia

Sulphonylureas were introduced in the mid 1950s. Some investigators used sulphony-lureas such as tolbutamide to study hypoglycaemia. (Visser 1967). The most important differences between insulin and sulphonylurea induced hypoglycaemia are their different effects on the pancreatic p cell and the ratio between peripheral and portal insulin levels, which may have a bearing on counterregulatory hormone release. In insulin induced hypoglycaemia, such as the insulin stress test or the hyperinsulinaemic clamp, endogenous insulin production is suppressed and peripheral and portal insulin levels are similar. However, sulphonylureas stimulate endogenous insulin production, leading to a higher portal to peripheral insulin ratio (Jackson et al. 1973). This may be an important methodological factor in choosing the hypoglycaemic stimulus, particularly when studying effects of the portal glucose sensor. Sulphonylurea induced hypoglycaemia has also been used to examine the influence of the fall in...

Stepped hypoglycaemic clamp

Intravenous insulin infusion Figure 5.6 Schematic showing the major elements of a stepped hypoglycaemic clamp. A primed continuous intravenous insulin infusion is started (black box) to raise circulating insulin concentrations (black line) rapidly to target. The resultant fall in plasma glucose (grey line) is controlled by a variable rate infusion of glucose solution (hatched bars). Figure 5.6 Schematic showing the major elements of a stepped hypoglycaemic clamp. A primed continuous intravenous insulin infusion is started (black box) to raise circulating insulin concentrations (black line) rapidly to target. The resultant fall in plasma glucose (grey line) is controlled by a variable rate infusion of glucose solution (hatched bars).

Measurement of counterregulatory hormones

The hormonal counterregulatory response to hypoglycaemia is a carefully orchestrated release of hormones that has a natural hierarchy in the non-diabetic individual that protects the individual from severe hypoglycaemia (Mitrakou et al. 1991). The first step is a reduction in insulin production, followed by the release of glucagon, adrenaline, cortisol and growth hormone (Cryer et al. 1989). Studies of counterregulation to hypoglycaemia have looked at either the magnitude of the counterregulatory hormone response to a fixed hypoglycaemic stimulus or the glucose concentration (often referred to as the threshold) at which the response is activated. The former can be done using a single-step design, with hormones collected at a fixed interval after reaching the nadir glucose. These studies are easy to interpret, as simple statistics can be used to compare the hormonal values at the glucose nadir. The latter study requires a slow controlled glucose fall. All studies require adequate...

Calculating glucose thresholds for hormone release

Glucose thresholds for release of counterregulatory hormones or onset of other responses to hypoglycaemia are defined as the plasma glucose concentration at which the response is fisrt significant. They can thus only be reliably identified in slow reductions in plasma glucose, preferably stepped, as described above. The critical issue is to decide before starting what determines a significant change. This can either be to a specific value or by a predefined degree of increase. The gold standard is to perform euglycaemic studies of the same duration in the same patients in the same conditions and compare the hypoglycaemic responses with the eugly-caemic absence of response in each subject. For smaller pilot studies, where this is impractical, some investigators have used a statistical definition such as a change in excess of two standard deviations over the mean basal readings - for this, one strictly requires at least five baseline measures for each subject in order to define the...

Measurement of glucose kinetics

A full description of the in vivo measurement of glucose kinetics is beyond the scope of this chapter. In human studies, stable isotopes are used in preference to radioisotopes to avoid unnecessary exposure to radiation. The principle is to label the substrate pool with a known amount of labeled substrate, and use the dilution of the labeled substrate as an indicator of the amount of tracee entering the system, from which any exogenous infusion is subtracted. Di-deutrated glucose is commonly used to differentiate endogenous glucose production from glucose uptake by peripheral tissues and the techniques, described in textbooks on measuring insulin sensitivity, can be used in hypoglycaemia research to establish the onset of endogenous glucose counterregulation. In using glucose tracers, it is essential to establish a steady state of tracer labeling in the blood before starting - this is usually achieved by giving a priming dose of tracer (which with stable isotopes does involve a...

Property two kinetic equivalence

2-3H or 2-2H glucose is detritiated or de-deuterated in the hydrogen exchanges that take place at phosphoglucose isomerase. This has no quantitative consequence in peripheral tissues but is important in the liver because tracer that has lost its label can be immediately dephosphorylated and re-released as unlabeled glucose. This would not be appropriate in the determination of an irreversible uptake of glucose in the liver or, by extrapolation, systemically - since it would include some part of this 'futile' cycle (glucose glucose-6-phosphate) (Katz & Dunn 1967 Hers & Hue 1983). Because the equilibration with water at the isomerase step might not be complete, a portion of the label may be retained both in the second and the first positions. Approximately 80 of the cycle is however accounted for by the detritiation de-deuteration (Wajngot et al. 1989), with the result that estimates of endogenous glucose production (EGP) made using this label in normal humans were found to be 17...

Fasted state net glucose synthesis from hepatic G6P

Figure 8.3 Metabolic Model for the Sources of Hepatic Glucose Output During Fasting Also shown is a 2H NMR spectrum of a MAG derivative prepared from plasma glucose of a heart failure patient with new-onset diabetes. The number above each signal represents the glucose position where the signal originated. The ratio of position 5 to position 2 (H5 H2) and position 6S to position 2 (H6S H2) enrichments as determined from the relative areas of the NMR signals are also shown. Applying these data to equations 1-4 gives the following estimates of flux contributions to fasting glucose production 7 from glycogenolysis, 67 from PEP and 26 from glycerol. Figure 8.3 Metabolic Model for the Sources of Hepatic Glucose Output During Fasting Also shown is a 2H NMR spectrum of a MAG derivative prepared from plasma glucose of a heart failure patient with new-onset diabetes. The number above each signal represents the glucose position where the signal originated. The ratio of position 5 to position 2...

Tracers for the study of adipose tissue lipolysis Free fatty acids

Free fatty acids (FFAs) are the major lipid fuel in the circulation, with a relatively high flux rate that can be estimated at approximately 100g day in healthy adults (Miles et al. 2004). The use of tracers for the study of FFA kinetics is nearly 50 years old (Frederickson & Gordon 1958), but there has been a renewed interest in FFA metabolism in recent years because of evidence that elevated FFA levels are likely mediators of insulin resistance (Boden et al. 1991), endothelial dysfunction (Steinberg et al. 1997) and hypertension (Stojiljkovic et al. 2001). Although there is in general an excellent correlation between plasma FFA concentration and FFA turnover (Armstrong et al. 1961), there are dramatic examples of how measurement of FFA concentration fails to detect changes in flux. For example, in normal and diabetic subjects, submaximal exercise results in a near-doubling of oleate turnover rate without a significant increase in the arterial concentration of this fatty acid...

Radioactive vs stable isotopes

The use of stable isotopes offers a very practical advantage, especially when studying glutamate and glutamine metabolism, a major nitrogen transport system. Darmaun et al. (1985) recognised that during sample preparation a substantial portion of glutamine is converted to glutamate. They developed a clever strategy to circumvent this artifact and avoid an erroneous interpretation of the data. Briefly, they demonstrated that when a known amount of 2H5 glutamine (M5) is added to a sample before preparation, one can correct the glutamate concentration and labeling by measuring the amount of M5 glutamate (i.e. if 2H5 glutamine (M5) is degraded it will appear as 2H5 glutamate (M5)). This method was used to study glutamate and glutamine kinetics in patients with type 1 diabetes under conditions similar to those experienced after a night of poor metabolic control (Darmaun et al. 1991). In support of the hypothesis that insulin deficiency leads to increased proteolysis and muscle wasting,...

Influence of tracer labeling

Tracer metabolism during studies of leucine kinetics in diabetes. They observed an elevated leucine nitrogen flux (transamination) in poorly controlled diabetics and noted that treatment with insulin reduces leucine nitrogen flux (transamination) in patients with either type 1 or type 2 diabetes.

Using rates of amino acid flux to determine wholebody protein turnover

Numerous tracer studies of leucine flux and whole-body protein turnover have been performed in diabetic subjects. The data suggest a tendency for increased protein breakdown in poorly controlled type 1 diabetics, and that intensive insulin therapy normalises leucine flux in most cases (Luzi et al. 1990 Lariviere et al. 1992). It appears that insulin action on whole-body protein turnover plays a greater role in modulating splanchnic vs leg muscle protein turnover in vivo (Nair et al. 1995). In contrast to studies done in type 1 diabetics, there appears to be some discrepancy regarding leucine flux and protein turnover in those with type 2 diabetes and related conditions. For example, studies performed in subjects with type 2 diabetes report no alterations in leucine flux during basal or insulin-stimulated conditions in patients with impaired regulation of glucose metabolism (Luzi et al. 1993). However, studies done in the offspring of patients with type 2 diabetes found evidence of...

Determining the molecular control of protein dynamics

First, one can examine the role of gene transcription in the control of protein levels by using real-time polymerase chain reaction assays to quantify the amount of transcribed mRNA or by performing in vitro translation assays to quantify the amount of translatable mRNA. In an interesting study, Peavy et al. (1978) used the flooding dose method to determine that alloxan-induced diabetes leads to a reduction in albumin synthesis in vivo. They then used an in vitro translation assay and determined that impaired gene transcription plays an important role in limiting albumin synthesis. Second, to quantify 'translation efficiency', one can measure the polyribosome profile. Peavy et al. (1985) found no differences in the polyribosome profiles of livers from normal vs alloxan-induced diabetic rodents, suggesting that diabetes-related decreases in albumin synthesis are not the result of impaired translation efficiency. These observations support their initial studies, in which the abundance...

Skeletal muscle Glucose fluxes

Radioactive tracer and stable isotope dilution techniques from 1960s to 1980s identified skeletal muscle as one of the major organs responsible for whole body insulin resistance under insulin stimulated conditions (DeFronzo 1988). In vitro studies on cellular suspensions, in vivo studies measuring arterio-venous isotope balance, and studies using skeletal muscle biopsies or freeze clamps of animal tissue all tried to identify the rate-controlling step in the glycogenic and glycolytic pathways that was responsible for the development of insulin resistance. The coordinated regulation of the activity of several enzymes on these pathways by insulin has complicated attempts to assign the conventional rate-limiting step

Perturbation of metabolic flux control the role of substrate overabundance

It is well known that increased circulating triglycerides and FFA are frequently associated with pathophysiology of insulin resistance and diabetes mellitus. Searching for the mechanism of their action on glucose metabolism, Sir Randle et al. (1963) observed that elevated circulating free fatty acids (FFA) impair skeletal muscle glucose uptake. The results of his studies allowed him to postulate the hypothesis that substrate competition for mitochondrial oxidation is the major mechanism involved in this action. According to this hypothesis, experimental challenge by FFA would first increase the intracellular glucose-6-phosphate

Hormonal regulation of hepatic glucose metabolism

Hormones like insulin and glucagon are known to affect the enzymes involved in glycogen metabolism. The 1-13C -labeled glucose- 1-12C glucose chase technique was used to assess flux rates through glycogen phosphorylase in healthy humans, showing that rate of hepatic glycogen synthesis depends on portal vein insulin, requiring portal vein insulin concentration in the range of 130-170 pmol.l-1 for half-maximal stimulation of glycogen synthesis (Roden et al. 1996a) (Figure 11.13), which is good agreement with that for suppression of glucose production by insulin (Rizza et al.1981). Further study (Petersen et al. 1998b) trying to sort out the effects of hyperglycaemia and hyperinsulinaemia per se on hepatic glycogen metabolism showed that promotion of hepatic glycogen cycling may be the mechanism by which insulin decreases glycogenolysis and glucose production during euglycaemia. Additional stimulation of hepatic glycogen synthesis by low dose fructose infusion ( 3.5 mol.kg_1.min_1)...

Perturbation of hepatic metabolic fluxes by substrate overabundance

Elevated circulating free fatty acids are associated with increased fasting EGP in type 2 diabetes (Hundal et al. 2000) furthermore, diminished postprandial hormonal response is not able to suppress FFA concentration to the same extent as in non-diabetic populations (Krssak et al. 2004), which again may contribute to higher postprandial EGP in T2DM (Singhal et al. 2002 Krssak et al. 2004). Studies in young, healthy volunteers have shown that an experimentally elevated FFA concentration increased gluconeogenesis (Roden et al. 2000), which led to a lower rate of hepatic glycogen breakdown (Stingl et al. 2001). However, matching insulin, glucagon, glucose and FFA concentrations during the clamp protocol in T2DM (Krssak et al. 2004) did not fully restore hepatic glycogen synthesis, indicating an additional defect besides the effects of metabolic and hormonal differences. But study focused on the effects of amino acids on hepatic glucose fluxes have shown that experimental amino acid...

Brain activity energy metabolism and neurotransmitter cycling

Epidemiological, cross-sectional and prospective associations between T2DM and moderate cognitive impairment of memory and executive functions have been discovered and were reviewed by Pasquier et al. (2006). Both vascular and non-vascular factors were found to be the reasons for dementia in diabetes (Stewart & Liolitsa 1999). Direct study using functional BOLD MRI of brain activation has shown that hypoglycaemia induced impairment of brain function is associated with task specific localised reduction in brain activation (Rosenthal et al. 2001). Higher increase of deoxygenation, depicted as higher BOLD signal in active brain areas, can help to overcome the energy shortage caused by hypoglycaemia (Rosenthal et al. 2001) or micovascular damage in type 1 diabetic patients (Wessels et al. 2006) with retinopathy. Certain overcompensation mechanisms can be observed in 31P and 1H MR spectroscopic observation of energy metabolism in type 1 diabetic patients, where, in contrast to healthy...

Applications of PET for the assessment of skeletal muscle metabolism

By combining PET and the glucose-insulin clamp technique, insulin resistance for glucose was shown to localise in skeletal muscle in type 1 and type 2 diabetes (Nuutila et al. 1993 Utriainen et al. 1998). Using compartmental modeling, insulin is shown to affect transport and phosphorylation but not extracellular kinetics, with the transport step becoming the main site of control (Kelley et al. 1999 Bertoldo et al. 2001). Skeletal muscle free fatty acid uptake measured using 18-F-FTHA under fasting conditions has been shown to be decreased with insulin use, but myocardial free fatty acid uptake is similar in both patients with impaired glucose tolerance and normal patients (Turpeinen et al. 1999), suggesting that not only glucose but also lipid metabolism is defective in type 2 diabetes. Perfusion regulates muscle oxygen and nutrient supply at rest and during exercise and is distributed heterogeneously between and within skeletal muscles in humans (Kalliokoski et al. 2001). In...

Magnetic Resonance Imaging MRI and spectroscopy

Figure 13.3 Assessment of Abdominal Fat Storage by Computed Tomography (CT) Representative cross-sectional abdominal CT scans of a lean (A) and an obese (B) research volunteer, demonstrating the fat muscle CT contrast shown with demarcations of visceral (large arrowheads), deep subcutaneous (open arrows) and superficial subcutaneous (closed arrows) adipose tissue (AT) depots. The fascia (small arrowhead) within subcutaneous abdominal AT was used to distinguish superficial from deep depot. In the two CT scans shown, the area of superficial subcutaneous AT was similar (144 vs 141 cm2), whereas areas of deep subcutaneous (126 vs 273 cm2) and visceral (84 vs 153 cm2) AT were quite different. Insulin-stimulated glucose metabolism was 6.1 and 4.0 mg min-1 kg FFM-1 in lean and obese volunteers, respectively (FFM fat-free mass). Reproduced from Kelley D E et al. (2000) Am J Physiol Endocrinol Metab 278 (5) E941-E948. Courtesy of the American Physiological Society. Figure 13.3 Assessment of...

Liver intrahepatic lipids

As with skeletal muscle, elevated circulating free fatty acids (FFA) are associated with hepatic features of insulin resistance increased fasting endogenous glucose production (EGP Hundal et al. 2000), insufficient suppression of EGP in the postprandial state (Singhal et al. 2002 Krssak et al. 2004) and defects in hepatic glycogen synthesis (Krssak et al. 2004) in type 2 diabetes. Studies in young healthy volunteers have shown that experimentally elevated FFA concentration increased gluconeogenesis (Roden et al. 2000), which then led to a lower rate of hepatic glycogen breakdown (Stingl et al. 2001). Besides direct effects on hepatic glucose metabolism, chronically increased circulating FFA favours intrahepatic lipid accumulation (Krssak & Roden 2004 Roden 2006), which relationship to whole-body and hepatic glucose fluxes can effectively be studied only using modern imaging techniques. As in the skeletal muscle, the first studies were designed to find an association between hepatic...

Whole body fat distribution subcutaneous and visceral fat

Even though the total fat mass determines the plasma pool of FFA and thereby the FFA flux from adipose to non-adipose tissue (Lewis et al. 2002), there are differences in the relationship of subcutaneous and visceral fat depots to features of peripheral and hepatic insulin sensitivity (Misra et al. 1997). Visceral fat cells are more sensitive than subcutaneous fat cells to the lipolytic effect of catecholemines and less sensitive to the antilipolytic and fatty acid re-esterification effects of insulin (Kahn & Flier 2000). Furthermore, the venous effluent of visceral fat depots leads directly into the portal vein, resulting in greater FFA flux to the liver. This makes the visceral fat depots more efficient than subcutaneous fat in influencing the carbohydrate metabolism in the human body (Kissebah 1996). Tokunaga et al. 1983 Busetto et al. 1992 Thomas & Bell 2003 Positano et al. 2004 Machann et al. 2005 ). Using these methods, total amount of visceral fat was linked to different...

Percutaneous needle biopsy of skeletal muscle

Extensive investigation of the metabolism of normal and abnormal tissue requires a simple method for tissue sampling. The percutaneous muscle biopsy technique developed and introduced by Bergstrom in the 1960s provides a simple and repeatable sampling method (Bergstrom 1962, 1975), which has made skeletal muscle one of the few tissues suitable for direct studies of structure and metabolic functions in human subjects. The percutaneous muscle biopsy procedure has been used widely to study many aspects of human muscle metabolism, in particular changes caused by exercise, insulin resistance and type 2 diabetes. As reviewed by others, this method of sampling is rapid and relatively atraumatic (Goldberger et al. 1978 Edwards et al. 1980, 1983). It carries a very low complication rate and repeated biopsies are well tolerated, allowing follow-up studies after treatment.

Advantages and limitations of needle biopsy

The needle biopsy circumvents many of the disadvantages of the open muscle biopsy, which include higher costs, the need for general anaesthetic, increased scarring and the inconvenience of repeated biopsies (Goldberger et al. 1978 Edwards et al. 1980, 1983). The fact that many of our patients and control subjects have participated in several studies involving muscle biopsies emphasises that this technique is easy to learn, repeatable and relatively atraumatic. It is a safe procedure that is almost free of complication. As repeated biopsies are generally well tolerated, biopsies can be taken before, during and after acute or chronic intervention, e.g. insulin stimulation, lipid infusion, exercise, treatment with drugs, training etc. There is always a slight delay in freezing the specimen. This can lead to inaccuracy in the determination of some muscle metabolites and cause areas of artifact formation, making morphological studies troublesome. Nevertheless, most analytical methods are...

Morphology of skeletal muscle

Morphological studies of skeletal muscle are based on analysis of thin sections of muscle using either light microscopy for histological and histochemical studies or electron microscopy. Using a wide range of procedures, these techniques allow the assessment of changes in muscle structure, fibre type composition and ultrastructure associated with any disease affecting skeletal muscle. Moreover, morphological analysis is often used to clarify whether proteins verified in muscle tissue extracts originate from muscle or contaminating tissue types, and to determine the precise subcellular localisation of proteins and organelles within muscle cells. Combining these techniques with the principles of stereology, which is the field describing methods for counting and measuring morphological structures in an unbiased way (Gundersen et al. 1988), it is also possible to obtain quantitative measurements of abnormalities associated with e.g. insulin resistance and type 2 diabetes. There are...

Human myotube cultures

Cultured myotubes offer a unique model for separating the genetic influence on insulin resistance and type 2 diabetes from environmental factors (Henry et al. 1996a,b Nikoulina et al. 2001 Gaster et al. 2002, 2004a,b, 2005 Gaster & Beck-Nielsen 2004 Mclntyre et al. 2004). As an in vitro model of skeletal muscle, they are devoid of extracellular influence and offer excellent material for performing studies under standardised conditions. The basis of this model system is satellite cells (quiescent multipotent cells) lying between the basal membrane and the sarcolemma of muscle fibres. They are isolated, scaled up and allowed to differentiate into multinuclear myotubes. The underlying idea is that cultured muscle cells express their genetic background only when precultured under physiological conditions and Figure 14.6 GLUT4 Density in Slow and Fast Fibres GLUT4 densities in slow and fast skeletal muscle fibres in control subjects, obese subjects and subjects with type 2 diabetes were...

Limitations of human myotubes

Figure 14.7 Phase Contrast Appearance of Human Satellite Cell Culture Human satellite cell cultures were established, grown, and differentiated as described by Gaster et al. (2001a,b). Morphological appearance was investigated by phase contrast microscopy. A) mononucleated cells under proliferation (X100) B) day 8 differentiated cultures, cultured under physiological conditions (5.0mmol l glucose and 25pmol l insulin). The cultures contain many multinucleated myofibres (x200). Figure 14.7 Phase Contrast Appearance of Human Satellite Cell Culture Human satellite cell cultures were established, grown, and differentiated as described by Gaster et al. (2001a,b). Morphological appearance was investigated by phase contrast microscopy. A) mononucleated cells under proliferation (X100) B) day 8 differentiated cultures, cultured under physiological conditions (5.0mmol l glucose and 25pmol l insulin). The cultures contain many multinucleated myofibres (x200). The human myotube model can,...

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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