Thiazolidinedione insulin sensitizers and the heart: a tale of two organs?

Heart failure in the patient with diabetes: Epidemiology, aetiology, prognosis, therapy and the effect of glucose-lowering medications

In people with type 2 diabetes the frequency of heart failure (HF) is increased and mortality from HF is higher than with non-diabetic HF. The increased frequency of HF is attributable to the cardiotoxic tetrad of ischaemic heart disease, left ventricular hypertrophy, diabetic cardiomyopathy and an extracellular volume expansion resistant to atrial natriuretic peptides. Activation of the renin-angiotensin-aldosterone system and sympathetic nervous systems results in cardiac remodelling, which worsens cardiac function. Reversal of remodelling can be achieved, and cardiac function improved in people with HF with reduced ejection fraction (HFrEF) by treatment with angiotensin-converting enzyme inhibitors and β-blockers. However, with HF with preserved ejection fraction (HFpEF), only therapy for the underlying risk factors helps. Blockers of mineralocorticoid receptors may be beneficial in both HFrEF and HFpEF. Glucose-lowering drugs can have a negative effect (insulin, sulphonylureas, dipeptidyl peptidase-4 inhibitors and thiazolidinediones), a neutral effect (α-glucosidase inhibitors and glucagon-like peptide-1 receptor agonists) or a positive effect (sodium-glucose co-transporter-2 inhibitors and metformin).

Glucose dysregulation and response to common anti-diabetic agents in the FATZO/Pco mouse

The FATZO/Pco mouse is the result of a cross of the C57BL/6J and AKR/J strains. The crossing of these two strains and the selective inbreeding for obesity, insulin resistance and hyperglycemia has resulted in an inbred strain exhibiting obesity in the presumed presence of an intact leptin pathway. Routinely used rodent models for obesity and diabetes research have a monogenic defect in leptin signaling that initiates obesity. Given that obesity and its sequelae in humans are polygenic in nature and not associated with leptin signaling defects, the FATZO mouse may represent a more translatable rodent model for study of obesity and its associated metabolic disturbances. The FATZO mouse develops obesity spontaneously when fed a normal chow diet. Glucose intolerance with increased insulin levels are apparent in FATZO mice as young as 6 weeks of age. These progress to hyperglycemia/pre-diabetes and frank diabetes with decreasing insulin levels as they age. The disease in these mice is multi-faceted, similar to the metabolic syndrome apparent in obese individuals, and thus provides a long pre-diabetic state for determining the preventive value of new interventions. We have assessed the utility of this new model for the pre-clinical screening of agents to stop or slow progression of the metabolic syndrome to severe diabetes. Our assessment included: 1) characterization of the spontaneous development of disease, 2) comparison of metabolic disturbances of FATZO mice to control mice and 3) validation of the model with regard to the effectiveness of current and emerging anti-diabetic agents; rosiglitazone, metformin and semaglutide.

CONCLUSION

Male FATZO mice spontaneously develop significant metabolic disease when compared to normal controls while maintaining hyperglycemia in the presence of high leptin levels and hyperinsulinemia. The disease condition responds to commonly used antidiabetic agents.

Interaction of β1-adrenoceptor with RAGE mediates cardiomyopathy via CaMKII signaling

Stimulation of β1-adrenergic receptor (β1AR), a GPCR, and the receptor for advanced glycation end-products (RAGE), a pattern recognition receptor (PRR), have been independently implicated in the pathogenesis of cardiomyopathy caused by various etiologies, including myocardial infarction, ischemia/reperfusion injury, and metabolic stress. Here, we show that the two distinctly different receptors, β1AR and RAGE, are mutually dependent in mediating myocardial injury and the sequelae of cardiomyopathy. Deficiency or inhibition of RAGE blocks β1AR- and RAGE-mediated myocardial cell death and maladaptive remodeling. Ablation or blockade of β1AR fully abolishes RAGE-induced detrimental effects. Mechanistically, RAGE and β1AR form a complex, which in turn activates Ca²⁺/calmodulin-dependent kinase II (CaMKII), resulting in loss of cardiomyocytes and myocardial remodeling. These results indicate that RAGE and β1AR not only physically crosstalk at the receptor level, but also functionally converge at the common mediator, CaMKII, highlighting a combined inhibition of RAGE and β1AR as a more effective therapy to treat diverse cardiovascular diseases, such as myocardial infarction, ischemia/reperfusion injury, and diabetic cardiovascular complications.

Metformin and metabolic diseases: a focus on hepatic aspects

Metformin has been widely used as a first-line anti-diabetic medicine for the treatment of type 2 diabetes (T2D). As a drug that primarily targets the liver, metformin suppresses hepatic glucose production (HGP), serving as the main mechanism by which metformin improves hyperglycemia of T2D. Biochemically, metformin suppresses gluconeogenesis and stimulates glycolysis. Metformin also inhibits glycogenolysis, which is a pathway that critically contributes to elevated HGP. While generating beneficial effects on hyperglycemia, metformin also improves insulin resistance and corrects dyslipidemia in patients with T2D. These beneficial effects of metformin implicate a role for metformin in managing non-alcoholic fatty liver disease. As supported by the results from both human and animal studies, metformin improves hepatic steatosis and suppresses liver inflammation. Mechanistically, the beneficial effects of metformin on hepatic aspects are mediated through both adenosine monophosphate-activated protein kinase (AMPK)-dependent and AMPK-independent pathways. In addition, metformin is generally safe and may also benefit patients with other chronic liver diseases.

Thiazolidinediones and risk of heart failure in patients with or at high risk of type 2 diabetes mellitus: a meta-analysis and meta-regression analysis of placebo-controlled randomized clinical trials

BACKGROUND

Recent meta-analyses of randomized clinical trials (RCTs) demonstrated a higher risk of heart failure (HF) with the use of thiazolidinediones (TZDs). However, this effect may have been diluted by including active controls. Also, it is uncertain whether the risk of HF is similar with rosiglitazone and pioglitazone.

OBJECTIVES

This study quantified the risks of HF with the use of TZDs in patients with or at high risk of developing type 2 diabetes mellitus (DM), and evaluated differential effects by type of TZD. Secondarily, we evaluated risks of peripheral edema.

METHODS

We performed a systematic review and meta-analysis of placebo-controlled RCTs evaluating the effect of rosiglitazone or pioglitazone on investigator-reported HF and edema. Articles published before 31 December 2009 were searched in MEDLINE, The Web of Science, and Scopus, and the data were extracted by three investigators. RCTs with ≥100 patients and ≥3 months of follow-up were included. We quantified the effect of TZDs as odds ratios (ORs) by using the Mantel-Haenzel and alternative models. We further evaluated the risk of serious/severe HF, and the effect of several trial characteristics on HF risk by subgroup analysis and meta-regression analysis.

RESULTS

29 trials (n = 20 254) were evaluated. TZDs were significantly associated with HF (TZD 360/6807 [5.3%] vs placebo 234/6328 [3.7%], OR 1.59; 95% CI 1.34, 1.89; p < 0.00001). The risk of HF was higher with rosiglitazone than with pioglitazone (2.73 [95% CI 1.46, 5.10] vs 1.51 [1.26, 1.81]; p = 0.06). TZDs were associated with a similar risk of serious/severe HF (OR 1.47; 95% CI 1.16, 1.87; p = 0.002). Use of TZDs was also associated with edema (OR 2.04; 95% CI 1.85, 2.26; p < 0.00001). HF and edema risks were consistent using Peto and random effects models. Risks of HF were significantly high for the subgroups of trials including patients with or at high risk for type 2 DM, and for the subgroup of trials with ≥12 months of follow-up. Meta-regression analysis showed that trials with lower overall baseline risk had higher HF risks.

CONCLUSION

In placebo-controlled trials of adult patients with or at high risk for type 2 DM, TZD therapy is significantly and consistently associated with a higher risk of HF. The risk of serious/severe HF is also increased with the use of TZDs. HF risks are similar to those of meta-analyses combining active- and placebo-controlled trials. The benefit/risk profile of TZDs should be considered when treating diabetic patients with or without prior HF.

Maternal omega-3 supplementation increases fat mass in male and female rat offspring

Adipogenesis and lipogenesis are highly sensitive to the nutritional environment in utero and in early postnatal life. Omega-3 long chain polyunsaturated fatty acids (LCPUFA) inhibit adipogenesis and lipogenesis in adult rats, however it is not known whether supplementing the maternal diet with omega-3 LCPUFA results in reduced fat deposition in the offspring. Female Albino Wistar rats were fed either a standard chow (Control, n = 10) or chow designed to provide ∼15 mg/kg/day of omega-3 LCPUFA, chiefly as docosahexaenoic acid (DHA), throughout pregnancy and lactation (Omega-3, n = 11) and all pups were weaned onto a commercial rat chow. Blood and tissues were collected from pups at 3 and 6 weeks of age and weights of visceral and subcutaneous fat depots recorded. The expression of adipogenic and lipogenic genes in the subcutaneous and visceral fat depots were determined using quantitative real time reverse transcription-PCR. Birth weight and postnatal growth were not different between groups. At 6 weeks of age, total percentage body fat was significantly increased in both male (5.09 ± 0.32% vs. 4.56 ± 0.2%, P < 0.04) and female (5.15 ± 0.37% vs. 3.89 ± 0.36%, P < 0.04) offspring of omega-3 dams compared to controls. The omega-3 LCPUFA content of erythrocyte phospholipids (as a% of total fatty acids) was higher in omega-3 offspring (6.7 ± 0.2% vs. 5.6 ± 0.2%, P < 0.001). There was no effect of maternal omega-3 LCPUFA supplementation on the expression of adipogenic or lipogenic genes in the offspring in either the visceral or subcutaneous fat depots. We have therefore established that an omega-3 rich environment during pregnancy and lactation in a rodent model increases fat accumulation in both male and female offspring, particularly in subcutaneous depots, but that this effect is not mediated via upregulation adipogenic/lipogenic gene transcription. These data suggest that maternal n−3 LCPUFA supplementation during pregnancy/lactation may not be an effective strategy for reducing fat deposition in the offspring.

Advances in the treatment of type 2 diabetes mellitus

There is a rising worldwide prevalence of diabetes, especially type 2 diabetes mellitus (T2DM), which is one of the most challenging health problems in the 21st century. The associated complications of diabetes, such as cardiovascular disease, peripheral vascular disease, stroke, diabetic neuropathy, amputations, renal failure, and blindness result in increasing disability, reduced life expectancy, and enormous health costs. T2DM is a polygenic disease characterized by multiple defects in insulin action in tissues and defects in pancreatic insulin secretion, which eventually leads to loss of pancreatic insulin-secreting cells. The treatment goals for T2DM patients are effective control of blood glucose, blood pressure, and lipids (if elevated) and, ultimately, to avert the serious complications associated with sustained tissue exposure to excessively high glucose concentrations. Prevention and control of diabetes with diet, weight control, and physical activity has been difficult. Treatment of T2DM has centered on increasing insulin levels, either by direct insulin administration or oral agents that promote insulin secretion, improving sensitivity to insulin in tissues, or reducing the rate of carbohydrate absorption from the gastrointestinal tract. This review presents comprehensive and up-to-date information on the mechanism(s) of action, efficacy, pharmacokinetics, pleiotropic effects, drug interactions, and adverse effects of the newer antidiabetic drugs, including (1) peroxisome proliferator-activated-receptor-γ agonists (thiazolidinediones, pioglitazone, and rosiglitazone); (2) the incretin, glucagon-like peptide-) receptor agonists (incretin-mimetics, exenatide. and liraglutide), (3) inhibitors of dipeptidyl-peptidase-4 (incretin enhancers, sitagliptin, and vildagliptin), (4) short-acting, nonsulfonylurea secretagogue, meglitinides (repaglinide and nateglinide), (5) amylin anlog-pramlintide, (6) α-glucosidase inhibitors (miglitol and voglibose), and (7) colesevelam (a bile acid sequestrant). In addition, information is presented on drug candidates in clinical trials, experimental compounds, and some plants used in the traditional treatment of diabetes based on experimental evidence. In the opinion of this reviewer, therapy based on orally active incretins and incretin mimetics with long duration of action that will be efficacious, preserve the β-cell number/function, and block the progression of diabetes will be highly desirable. However, major changes in lifestyle factors such as diet and, especially, exercise will also be needed if the growing burden of diabetes is to be contained.

Dysregulation of epithelial Na+ absorption induced by inhibition of the kinases TORC1 and TORC2

BACKGROUND AND PURPOSE

Although the serum and glucocorticoid-inducible protein kinase 1 (SGK1) appears to be involved in controlling epithelial Na(+) absorption, its role in this physiologically important ion transport process is undefined. As SGK1 activity is dependent upon target of rapamycin complex 2 (TORC2)-catalysed phosphorylation of SGK1-Ser(422) , we have explored the effects of inhibiting TORC2 and/or TORC1 upon the hormonal control of Na(+) absorption.

EXPERIMENTAL APPROACH

Na(+) absorption was quantified electrometrically in mouse cortical collecting duct cells (mpkCCD) grown to confluence on permeable membranes. Kinase activities were assessed by monitoring endogenous protein phosphorylation, with or without TORC1/2 inhibitors (TORIN1 and PP242) and the TORC1 inhibitor: rapamycin.

KEY RESULTS

Inhibition of TORC1/2 (TORIN1, PP242) suppressed basal SGK1 activity, prevented insulin- and dexamethasone-induced SGK1 activation, and caused modest (10-20%) inhibition of basal Na(+) absorption and substantial (∼80%) inhibition of insulin/dexamethasone-induced Na(+) transport. Inhibition of TORC1 did not impair SGK1 activation or insulin-induced Na(+) transport, but did inhibit (∼80%) dexamethasone-induced Na(+) absorption. Arginine vasopressin stimulated Na(+) absorption via a TORC1/2-independent mechanism.

CONCLUSION AND IMPLICATIONS

Target of rapamycin complex 2, but not TORC1, is important to SGK1 activation. Signalling via phosphoinositide-3-kinase/TORC2/SGK1 can explain insulin-induced Na(+) absorption. TORC2, but not TORC1, is also involved in glucocorticoid-induced SGK1 activation but its role is permissive. Glucocorticoid-induced Na(+) transport displayed a requirement for TORC1 activity. Therefore, TORC1 and TORC2 contribute to the regulation of Na(+) absorption. Pharmacological manipulation of TORC1/2 signalling may provide novel therapies for Na(+)-sensitive hypertension.

Effects of nominally selective inhibitors of the kinases PI3K, SGK1 and PKB on the insulin-dependent control of epithelial Na+ absorption

BACKGROUND AND PURPOSE

Insulin-induced Na(+) retention in the distal nephron may contribute to the development of oedema/hypertension in patients with type 2 diabetes. This response to insulin is usually attributed to phosphatidylinositol-3-kinase (PI3K)/serum and glucocorticoid-inducible kinase 1 (SGK1) but a role for protein kinase B (PKB) has been proposed. The present study therefore aimed to clarify the way in which insulin can evoke Na(+) retention.

EXPERIMENTAL APPROACH

We examined the effects of nominally selective inhibitors of PI3K (wortmannin, PI103, GDC-0941), SGK1 (GSK650394A) and PKB (Akti-1/2) on Na(+) transport in hormone-deprived and insulin-stimulated cortical collecting duct (mpkCCD) cells, while PI3K, SGK1 and PKB activities were assayed by monitoring the phosphorylation of endogenous proteins.

KEY RESULTS

Wortmannin substantially inhibited basal Na(+) transport whereas PI103 and GDC-0941 had only very small effects. However, these PI3K inhibitors all abolished insulin-induced Na(+) absorption and inactivated PI3K, SGK1 and PKB fully. GSK650394A and Akti-1/2 also inhibited insulin-evoked Na(+) absorption and while GSK650394A inhibited SGK1 without affecting PKB, Akti-1/2 inactivated both kinases.

CONCLUSION AND IMPLICATIONS

While studies undertaken using PI103 and GDC-0941 show that hormone-deprived cells can absorb Na(+) independently of PI3K, PI3K seems to be essential for insulin induced Na(+) transport. Akti-1/2 does not act as a selective inhibitor of PKB and data obtained using this compound must therefore be treated with caution. GSK650394A, on the other hand, selectively inhibits SGK1 and the finding that GSK650394A suppressed insulin-induced Na(+) absorption suggests that this response is dependent upon signalling via PI3K/SGK1.

Hydroxy monounsaturated fatty acids as agonists for peroxisome proliferator-activated receptors

The physiological and pathological role of oxidized polyunsaturated fatty acids (PUFAs) has been extensively studied, whereas those of hydroxy monounsaturated fatty acids (MUFAs) are not well understood. This study demonstrated that 11-hydroxy-(9Z)-octadecenoic acid ((9Z)-11-HOE), which was isolated from adlay seeds (Coix lacryma-jobi L. var. ma-yuen STAF.), can activate peroxisome proliferator-activated receptor (PPAR)alpha, delta and gamma in luciferase reporter assays more efficiently than (9Z)-octadecenoic acid (oleic acid), and to the same degree as linoleic acid. (9Z)-11-HOE increased the mRNA levels of UCP2 and CD36 in C2C12 myotubes and THP- 1 cells, respectively, and these effects were blocked by the PPARdelta- and gamma-specific antagonists GSK0660 and T0070907, respectively. Evaluation of the structure.activity relationship between hydroxy MUFAs and PPAR activation revealed that (9E)-11-HOE, the geometrical isomer of (9Z)-11-HOE, activated PPARs more potently than (9Z)-11-HOE, and that PPAR activation by hydroxyl MUFAs was not markedly influenced by the position of the hydroxy group or the double bond, although PPARdelta seemed to possess ligand specificity different to that of PPARalpha or gamma . Additionally, the finding that 11-hydroxy octadecanoic acid, the hydrogenated product of (9E)-11- HOE, was also capable of activating PPARs to a similar extent as (9E)-11-HOE indicates that the double bond in hydroxy MUFAs is not essential for PPAR activation. In conclusion, (9Z)-11-HOE derived from alday seeds and hydroxy MUFAs with a chain length of 16 or 18 acted as PPAR agonists. Hydroxylation of MUFAs may change these compounds from silent PPAR ligands to active PPAR agonists.

Fluid compartmental shifts with efficacious pioglitazone therapy in overweight monkeys: implications for peroxisome proliferator-activated receptor-gamma agonist use in prediabetes

Pioglitazone is prescribed to improve insulin sensitivity in type 2 diabetes mellitus patients and has been discussed as a therapy for metabolic syndrome. Pioglitazone and other thiazolidinediones are associated with fluid retention and edema that may exacerbate existing or developing congestive heart failure, which is often present in these patients. Using a nonhuman primate model, our aims were to evaluate (1) whether fluid shifts were detectable in normoglycemic monkeys, (2) which fluid compartment changed, and (3) whether fluid retention was dose dependent. Seventeen adult male cynomolgus macaques (Macaca fascicularis) were studied in a Latin square design such that all animals received 0, 1, 2, and 5 mg/kg pioglitazone for 6 weeks with 2 weeks of washout between dosing intervals. Doses approximated human exposures achieved with 30, 45, and 60 mg. At the end of each period, animals were weighed and underwent dual-absorption x-ray absorption scanning for body composition measurements. Fluid volumes were quantitated by Evans blue dilution for plasma volume, equilibration of sodium bromide for extracellular water, and deuterated water for total body water. Significant (P < .05) effects were seen with expansion of PV at both the 2- and 5-mg/kg doses, along with reduced plasma sodium at 5 mg/kg; however, surrogate end points used to indicate fluid retention (body weight, hematocrit, total protein, and albumin) did not change significantly. Significant trends toward increases in interstitial fluid and extracellular water with increasing dose were apparent. Pioglitazone effectively improved metabolic status by significantly decreasing fasting glucose and triglycerides and increasing adiponectin. We conclude that thiazolidinedione-related plasma volume expansion occurs in nondiabetic primates and that fluid retention is detectable when compartments are directly measured.

Effects of peroxisome proliferator-activated receptor gamma agonists on Na+ transport and activity of the kinase SGK1 in epithelial cells from lung and kidney

BACKGROUND AND PURPOSE

Peroxisome proliferator-activated receptor gamma (PPARgamma) agonists, such as rosiglitazone and pioglitazone, sensitize cells to insulin, and are therefore used to treat type 2 diabetes. However, in some patients, these drugs induce oedema, and the present study tests the hypothesis that this side effect reflects serum and glucocorticoid-inducible kinase 1 (SGK1)-dependent enhancement of epithelia Na(+) absorption.

EXPERIMENTAL APPROACH

Na(+) absorbing epithelial cells (H441 cells, mpkCCD cells) on permeable membranes were mounted in Ussing chambers, and the effects of rosiglitazone (2 microM) and pioglitazone (10 microM) on transepithelial Na(+) absorption were quantified electrometrically. Changes in SGK1 activity were assessed by monitoring phosphorylation of residues within an endogenous protein.

KEY RESULTS

Both cell types absorbed Na(+) via an electrogenic process that was enhanced by insulin. In mpkCCD cells, this stimulation of Na(+) transport was associated with increased activity of SGK1, whereas insulin regulated Na(+) transport in H441 cells through a mechanism that did not involve activation of this kinase. Rosiglitazone and pioglitazone had no discernible effect on transepithelial Na(+) absorption in unstimulated or insulin-stimulated cells and failed to alter cellular SGK1 activity.

CONCLUSIONS AND IMPLICATIONS

Our results do not support the view that PPARgamma agonists stimulate epithelial Na(+) absorption or alter the control of cellular SGK1 activity. It is therefore likely that other mechanisms are involved in PPARgamma-mediated fluid retention, and a better understanding of these mechanisms may help with the identification of patients likely to develop oedema or heart failure when treated with these drugs.

Soluble epoxide hydrolase as a therapeutic target for cardiovascular diseases

The cardiovascular effects of epoxyeicosatrienoic acids (EETs) include vasodilation, antimigratory actions on vascular smooth muscle cells and anti-inflammatory actions. These endogenous lipid mediators are broken down into diols by soluble epoxide hydrolase (sEH), and so inhibiting this enzyme would be expected to enhance the beneficial cardiovascular properties of EETs. sEH inhibitors (sEHIs) that are based on 1,3-disubstituted urea have been rapidly developed, and have been shown to be antihypertensive and anti-inflammatory, and to protect the brain, heart and kidney from damage. Although challenges for the future exist - including improving the drug-like properties of sEHIs and finding better ways to target sEHIs to specific tissues - the recent initiation of the first clinical trials of sEHIs has highlighted the therapeutic potential of these agents.

Sarcolemmal fatty acid uptake vs. mitochondrial beta-oxidation as target to regress cardiac insulin resistance

Cardiomyopathy and heart failure are frequent comorbid conditions in type-2 diabetic patients. However, it has become increasingly evident that insulin resistance, type-2 diabetes, and cardiomyopathy are not independent variables, and are linked through changes in metabolism. Specifically, elevated intracellular levels of long-chain fatty acid (LCFA) metabolites are a central feature in the development of cardiac insulin resistance, and their prolonged accumulation is an important cause of heart failure. In the insulin-resistant heart, the abundance of the LCFA transporters CD36 and FABPpm at the sarcolemma of cardiac myocytes appears to be markedly increased. Because circulating LCFA levels are increased in insulin resistance, the cardiac LCFA metabolizing machinery is confronted with drastic increases in substrate supply. Indeed, LCFA esterification into triacylglycerol and other lipid intermediates is increased, as is beta-oxidation and reactive oxygen species production. Therapeutic strategies to normalize the cardiac LCFA flux would be most successful when the target is the rate-limiting step in cardiac LCFA utilization. Carnitine palmitoyltransferase (CPT)-I has long been considered to be this rate-limiting site and, accordingly, pharmacological inhibition of CPT-I, or beta-oxidation enzymes, has been proposed as an insulin-resistance-antagonizing strategy. However, recent evidence indicates that, instead, sarcolemmal LCFA transport mediated by CD36 in concert with FABPpm provides a major site of flux control. In this review, it is proposed that a pharmacologically imposed net internalization of CD36 and FABPpm is the preferable strategy to limit LCFA entry and accumulation of LCFA metabolites, to regress cardiac insulin resistance and, eventually, prevent diabetic heart failure.

Insulin Glargine: a review 8 years after its introduction

Insulin Glargine was the first long-acting insulin analog produced by recombinant DNA technology, approved for use by the US FDA in April 2000 and by the European Agency for the Evaluation of Medicinal Products in June, 2000. It has become the most widely used insulin in the USA owing to its long duration of action without a pronounced peak. The principal advantage of insulin Glargine over neutral protamine Hagedorn (NPH) insulin is in a lower frequency of hypoglycemic reactions, thus affording improved safety. It is used in both type 1 and type 2 diabetes, usually as a single daily dose. In type 2 patients, it is often the first insulin introduced as a single daily dose. Although insulin Glargine is typically administered as a single nighttime dose, it can be given in the morning or at any other time convenient for the patient. In labile type 1 diabetes, it is often most effective given as two daily injections. In obese, insulin-resistant patients, it may be best to administer insulin Glargine in two separate doses, owing to the high volumes of injected insulin required. Insulin Glargine does not treat postprandial hyperglycemia. It is necessary to supplement with short-acting insulin at mealtimes to control glucose surges after meals. Insulin Glargine is effective in hospitalized and postsurgical patients on account of its lack of pronounced insulin peaks and long duration of action. Although there is considerable use of Glargine in pregnant diabetic women, there is no definitive study to confirm its benefits. Insulin Glargine is thought to coprecipitate supplementary short-acting insulins when co-administered in the same syringe. Therefore, more injections are typically needed in the usual treatment regimen for insulin requiring diabetes. In many cases, constant basal insulin levels may be achieved with multiple overlapping doses of NPH insulin given together with short-acting insulin at mealtimes. Such a therapy may be less costly, but the major advantage of insulin Glargine remains the greater safety of a lower frequency of hypoglycemic reactions.

Adipokines in the treatment of diabetes mellitus and obesity

BACKGROUND

The physiology of adipose tissue plays a main role in the pathogenesis of type 2 diabetes mellitus. The secretion of adipocyte-derived hormones, in either an autocrine or a paracrine manner, has been proposed as a relevant mechanism in this process. In this sense, the administration and regulation of hormones derived from adipose tissue arises as an attractive option for treating metabolic disorders.

OBJECTIVE

To review the current understanding of the implication of adipokines in the development of obesity and insulin resistance, as well as their potential use as therapeutic agents.

METHODOLOGY

Review of scientific literature.

CONCLUSIONS

This review describes the role of adipokines in generating insulin resistance and the chronic low-grade inflammatory profile accompanying visceral obesity.

Peroxisome proliferator-activated receptor gamma ligands isolated from adlay seed (Coix lacryma-jobi L. var. ma-yuen STAPF.)

Through screening for natural ligands against peroxisome proliferator-activated receptor gamma (PPARgamma) using the PPARgamma luciferase reporter assay, 6 hydroxy unsaturated fatty acids were isolated from adlay seed (Coix lacryma-jobi L. var. ma-yuen STAPF.) extracts with acetone and 70% ethanol. The structures of these compounds were determined via spectral analysis as 13-hydroxy-(9E,11E)-octadecadienoic acid (13-E,E-HODE) (1), 9-hydroxy-(10E,12E)-octadecadienoic acid (9-E,E-HODE) (2), 9-hydroxy-(10E)-octadecenoic acid (3), 10-hydroxy-(8E)-octadecenoic acid (4), 8-hydroxy-(9E)-octadecenoic acid (5), 11-hydroxy-(9Z)-octadecenoic acid (6). 9-E,E-HODE (2) exhibited the most potent PPARgamma agonist activity of the isolated hydroxy unsaturated fatty acids. 9-E,E-HODE (2) and 13-E,E-HODE (1) are the respective geometrical isomers of 9-hydroxy-(10E,12Z)-octadecadienoic acid and 13-hydroxy-(9Z,11E)-octadecadienoic acid, both of which are likely to be natural PPARgamma agonists produced in various mammalian cells, suggesting that 9-E,E-HODE may also act as PPARgamma agonist.