Management of co-existing diabetes mellitus and dyslipidemia: defining the role of thiazolidinediones

HDL abnormalities in type 2 diabetes: Clinical implications

Atherosclerotic cardiovascular disease (ASCVD) represents the primary cause of mortality among patients with Type 2 Diabetes Mellitus (T2DM). In this population, High-Density Lipoprotein (HDL) particles exhibit abnormalities in number, composition, and function, culminating in diminished anti-atherosclerotic capabilities despite normal HDL cholesterol (HDL-C) concentrations. Hyperglycemic conditions contribute to these alterations in HDL kinetics, composition, and function, causing T2DM patients' HDL particles to exhibit decreased concentrations of diverse lipid species and proteins. Treatment of hyperglycemia has the potential to correct abnormal HDL particle attributes in T2DM; however, pharmacological interventions, including metformin and thiazolidinediones, yield inconsistent outcomes with respect to HDL-C concentrations and functionality. Despite numerous attempts with diverse drugs, pharmacologically augmenting HDL-C levels has not resulted in clinical benefits in mitigating ASCVD risk. In contrast, reducing Low Density Lipoprotein cholesterol (LDL-C) via statins and ezetimibe has demonstrated significant efficacy in curtailing CVD risk among T2DM individuals. Promising results have been observed in animal models and early-phase trials utilizing recombinant HDL and Lecitin Cholesterol Acyl Transferase (LCAT) -enhancing agents, but the evaluation of their efficacy and safety in large-scale clinical trials is ongoing. While aberrant HDL metabolism constitutes a prevalent aspect of dyslipidemia in T2DM, HDL cholesterol concentrations and composition no longer offer valuable insights for informing therapeutic decisions. Nevertheless, HDL metabolism remains a critical research area in T2DM, necessitating further investigation to elucidate the role of HDL particles in the development of diabetes-associated complications.

Role of social interaction, exercise, diet, and age on developing and untreated diabetes in cynomolgus monkeys

Type 2 diabetes mellitus is the most common form of diabetes that occurs in both human and nonhuman primates. Although spontaneously diabetic nonhuman primates are used extensively in diabetic related research and are a proven valuable tool for the study of the natural history of diabetes, little is known about the key factors that can cause this metabolic disorder and the preventative measures that could be employed to minimize the consequences of diabetes. Using a model of developing and untreated diabetes, this study describes the effects of housing arrangement (socially group- versus individually single-housed), exercise, diet, age, and sex on fasting plasma glucose, key lipids associated with diabetes, and bodyweight in two large cohorts of nonhuman primates. Key findings include exercise/housing arrangement's contribution to significant differences in bodyweight, levels of fasting plasma glucose, total cholesterol, and high- and low-density lipoproteins. Age also had profound effects on glucose, triglyceride and high-density lipoproteins, particularly in single-caged animals. Moreover, females had higher fasting glucose, total cholesterol and triglyceride levels than male counterparts within the same housing situations. These factors may be critical to identifying preventive measures that could eventually be used to minimize obesity and diabetes in humans.

Simvastatin Use in Patients with Type 2 Diabetes Mellitus: The Effects on Oxidative Stress

OBJECTIVES

Studies have shown that people with type 2 diabetes mellitus (T2DM) may develop atherosclerosis due to the disturbance in oxidative control and progressive dyslipidemia. Our study aimed to highlight the benefits of simvastatin treatment in improving serum lipids and reducing oxidative damage in patients with T2DM.

METHODS

Our randomized control trial included 56 patients with T2DM and dyslipidemia. The participants were on glibenclamide (5mg/day) during the period of the study. The patients were divided into two study groups (groups 1 and 2). Group 1 was the control group and consisted of 31 patients. Group 2 consisted of 25 participants, who were given simvastatin 20mg tablet once daily for 12 weeks. The control group did not receive simvastatin. Both groups were followed-up for measurement of blood pressure, pulse rate, serum lipids, and parameters of oxidative stress.

RESULTS

The simvastatin treated group showed a significant improvement with reduced erythrocyte glutathione compared to the control group (p<0.001). This was also associated with a significant reduction in erythrocyte malondialdehyde in the simvastatin treated group compared to the control group (p<0.001). Serum lipids reflected a similar improvement in the levels of erythrocyte malondialdehyde.

CONCLUSION

Our study highlights the beneficial role of simvastatin in improving the degree of oxidative stress in patients with T2DM through its effects on serum lipids and lipid peroxidation.

The Combination of Elevated Triglycerides and Abnormal Fasting Glucose Increases Risk of Cerebral Infarction in Patients With Mild to Moderate Hypercholesterolemia

Background:

While triglycerides (TGs) and diabetes increase the risk of cardiovascular disease (CVD), their combined effects have not been quantified. We explored the combined effect of elevated TGs and glucose on CVD in a post hoc analysis of the large-scale Management of Elevated Cholesterol in the Primary Prevention Group of Adult Japanese (MEGA) Study. Material and Methods: In the MEGA Study, 8214 patients with mild to moderate hypercholesterolemia were randomly allocated to the diet alone group or diet plus pravastatin group and followed for 5 years. Of those, 7832 patients included in the intention-to-treat analysis were stratified into 4 groups: abnormal fasting glucose (AFG) plus high TGs, high TGs alone, AFG alone, and normal fasting glucose plus normal TGs (reference). Cox proportional hazard models were used to compare the incidence of and mortality from CVD in the 4 groups.

Results:

Incidence of CVD and coronary heart disease was significantly higher in the groups with AFG alone (hazard ratio [HR], 2.02 and 3.38; P < .01, respectively) and AFG plus high TGs (HR, 2.87 and 3.87; P < .01, respectively) than the reference group. A similar relation was found in models adjusting for high-density lipoprotein cholesterol (HDL-C). Although the incidence of cerebral infarction was significantly higher only in the group with AFG plus high TGs (HR, 2.16; P = .01), it was marginally significantly higher than the reference group after adjustment for HDL-C (HR, 1.86; P = .06). Diet plus pravastatin treatment reduced the risk of cerebral infarction by 66% in the group with AFG plus high TGs ( P = .03).

Conclusions:

Our findings contribute to the formulation of the hypothesis that patients with hypercholesterolemia having AFG plus high TGs have an increased risk of cerebral infarction. These are compatible with the result from the main study that patients with hypercholesterolemia randomized to diet plus pravastatin had a reduced risk of cerebral infarction.

Optimization of ingredients for formulating a diabetic dietary supplement

A diabetic dietary supplement comprising of multiple ingredients was designed based on recommendation of Indian Council of Medical Research for a diabetic adult. Central composite rotatable design using three variables (ingredient source) and five responses comprising of sensory and physico-chemical attributes were used for computation of an optimized solution. All the responses fitted well into quadratic equation with R (2) > 0.80. The optimum levels of ingredient combinations recommended with 93% desirability were obtained. A total of 27 combinations were prepared and evaluated. The dietary supplement comprising of milk fat and groundnut oil (90:10), whey protein concentrate and sodium caseinate (50:50) and resistant starch and maltodextrin (70:30) were selected on 100 point sensory scale. The prepared supplement using recommended levels of ingredients contained 4.37 moisture, 15.93 protein, 10.15 fat, 66.15 carbohydrate and 3.39% ash.

Diabetic cardiomyopathy: understanding the molecular and cellular basis to progress in diagnosis and treatment

Diabetes mellitus is an important and prevalent risk factor for congestive heart failure. Diabetic cardiomyopathy has been defined as ventricular dysfunction that occurs in diabetic patients independent of a recognized cause such as coronary artery disease or hypertension. The disease course consists of a hidden subclinical period, during which cellular structural insults and abnormalities lead initially to diastolic dysfunction, later to systolic dysfunction, and eventually to heart failure. Left ventricular hypertrophy, metabolic abnormalities, extracellular matrix changes, small vessel disease, cardiac autonomic neuropathy, insulin resistance, oxidative stress, and apoptosis are the most important contributors to diabetic cardiomyopathy onset and progression. Hyperglycemia is a major etiological factor in the development of diabetic cardiomyopathy. It increases the levels of free fatty acids and growth factors and causes abnormalities in substrate supply and utilization, calcium homeostasis, and lipid metabolism. Furthermore, it promotes excessive production and release of reactive oxygen species, which induces oxidative stress leading to abnormal gene expression, faulty signal transduction, and cardiomyocytes apoptosis. Stimulation of connective tissue growth factor, fibrosis, and the formation of advanced glycation end-products increase the stiffness of the diabetic hearts. Despite all the current information on diabetic cardiomyopathy, translational research is still scarce due to limited human myocardial tissue and most of our knowledge is extrapolated from animals. This paper aims to elucidate some of the molecular and cellular pathophysiologic mechanisms, structural changes, and therapeutic strategies that may help struggle against diabetic cardiomyopathy.

Relationship between serum free T4 (FT4) levels and metabolic syndrome (MS) and its components in healthy euthyroid subjects

BACKGROUND

The metabolic syndrome (MS) is associated with increased life-time risk for atherosclerotic cardiovascular disease. While some reports suggest that MS and/or insulin resistance is associated with low serum free T4 (FT4) level in euthyroid subjects, this remains a controversial issue.

OBJECTIVE

To clarify the association of serum FT4 level with presence of MS and its components in healthy euthyroid subjects.

SUBJECTS AND MEASUREMENTS

For 44,196 euthyroid subjects (including 25,147 males) not taking thyroid hormone or antithyroid-drug and without liver or renal disease who participated in a routine health screening examination, we measured serum FT4, high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), fasting glucose, blood pressure (BP), height, weight, and waist circumference. Subjects were categorized into five groups according to their serum FT4 concentration. The association of FT4 quintiles with clinical and metabolic parameters of MS was analysed by significance test for linearity, and logistic regression analysis was used to calculate odds ratios (ORs) for risk of MS and each of its components, before and after adjustment for age.

RESULTS

In males, serum FT4 concentrations were positively associated with BP, fasting glucose, HDL-C, and TG levels, and negatively associated with waist circumference after adjustment for age (P for trend = 0.033 to < 0.001). Females also showed similar findings except that FT4 had no correlation with TG after adjustment for age (all P for trend < 0.001 except TG). The negative association between FT4 and waist circumference was not present in younger male subjects (< 50 years), and the positive association between FT4 and BP was more prominent in younger female subjects (< 50 years) than in older females (P < 0.05). In both sexes, the ORs for elevated BP and elevated fasting glucose were significantly higher in subjects in the highest FT4 quintile than those in the lowest FT4 quintile, while the ORs for abdominal obesity and low HDL-C were significantly lower. Subjects in the higher FT4 quintiles had a significantly lower prevalence of MS than those in the lowest FT4 quintile, but such differences disappeared after adjustment for age in both males and in females.

CONCLUSION

These results suggest that the interaction between serum FT4 and MS components could be different according to age as well as gender in euthyroid subjects. Although thyroid hormone significantly affected each component of MS, there was no association between serum FT4 level and presence of MS after adjustment for age in healthy euthyroid subjects.

Association between cigarette smoking, white blood cell count, and metabolic syndrome as defined by the Japanese criteria

OBJECTIVE

Cigarette smoking increases the circulating white blood cell (WBC) count and the prevalence of metabolic syndrome. We investigated the association between cigarette smoking, WBC count, and metabolic syndrome as defined by the Japanese criteria.

METHOD

Cross-sectional data from 3,687 men undergoing general health screening between 2005 and 2006 were analyzed.

RESULTS

After adjustment for age and total cholesterol, former and current smoking were associated with the highest WBC quartile (>or=6.3 x 10(3) cells/muL) with an odds ratio of 1.35 (95% CI 1.09-1.66, P=0.0055) and 4.45 (95% CI 3.69-5.37, P<0.0001), respectively. It was found that increased WBC count was a risk factor for metabolic syndrome; on the other hand, the current smoking was not found to be a predictor for metabolic syndrome, when each WBC count quartile was separately analyzed.

CONCLUSIONS

Our data suggest that the risk for MetS, defined by Japanese criteria, might be estimated by the WBC count in Japanese men irrespective of their smoking status, although it should also be noted that the cigarette smoking increases the number of circulating WBC count.

Peroxisome proliferator-activated receptor-gamma agonists for management and prevention of vascular disease in patients with and without diabetes mellitus

Inflammation is known to have a pathogenic role in atherosclerosis and the genesis of acute coronary syndromes. The peroxisome proliferator-activated receptor (PPAR)-gamma, which is expressed in many constituent cells of atheromatous plaques, inhibits the activation of several proinflammatory genes responsible for atheromatous plaque development and maturation. Agonists of this receptor, such as rosiglitazone and pioglitazone, are currently available for the treatment of type 2 diabetes mellitus, and several lines of evidence have shown that these drugs have antiatherogenic effects. Insulin resistance is associated with inflammation and has a key role in atherogenesis. The antiatherogenic and insulin sensitizing effects of the thiazolidinediones in patients with type 2 diabetes mellitus may be associated with this action. However, in recent years there has been growing evidence that the antiatherogenic effects of PPAR-gamma agonists are not confined to patients with diabetes mellitus. PPAR-gamma agonists have been shown to downregulate the expression of endothelial activation markers, reduce circulating platelet activity, improve flow-mediated dilatation and attenuate atheromatous plaque progression in patients without diabetes mellitus. These effects of PPAR-gamma agonists appear to result from both insulin sensitization and a direct modulation of transcriptional activity in the vessel wall. This review summarizes the current understanding of the role of PPAR-gamma agonists in atherogenesis and discusses their potential role in the treatment of coronary artery disease in patients with type 2 diabetes mellitus and in nondiabetic patients.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Miocardiopatía diabética

The world-wide estimated prevalence of diabetes mellitus for 2025 is of about 300 million, resulting from a higher prevalence of obesity and sedentary lifestyles in the developed world. The group of cardiovascular diseases is responsible for 80% of deaths among diabetic patients. Several authors have suggested that patients with diabetes mellitus have a predisposition to develop a form of cardiomyopathy, known as <<diabetic cardiomyopathy>>, which is not related to ischemic heart disease or hypertension, and may progress to cardiac failure. Such condition is known to be associated with a poor prognosis in patients with diabetes mellitus. The prevalence appears to be high. Thus, tissue Doppler techniques added to conventional echocardiography assessment have estimated it to be as high as 75%. However, the use of echocardiography as a screening tool in the asymptomatic diabetic population is problematic. Biomarkers of cardiac dysfunction have been proposed for diagnosis. In this article, we have assessed the role of biomarkers in the diagnosis of this condition and proposed a diagnostic algorithm that may be useful for the assessment of asymptomatic patients with diabetes.

Rosiglitazone versus bedtime insulin in the treatment of patients with conventional oral antidiabetic drug failure: a 1-year randomized clinical trial

This study was conducted to evaluate the efficacy and tolerability of rosiglitazone in the treatment of patients with secondary oral antidiabetic drug (OAD) failure and to directly compare its use with bedtime insulin. A total of 112 Chinese patients with type 2 diabetes and conventional OAD failure were recruited. Patients were randomly assigned to treatment with rosiglitazone or bedtime isophane insulin; they continued to take their original oral antidiabetic drugs. Glycemic index, other clinical profiles, and tolerability were assessed during treatment and 1 y after add-on treatment was provided. Among the 112 patients, mean age (+/-SD) was 58.2+/-11.0 y (median, 58 y; range, 37 to 84 y). Both rosiglitazone (n=56) and insulin (n=56) significantly improved fasting glucose (2.4 and 3.7 mmol/L, respectively) and hemoglobin A1c concentrations (1.1% and 1.3%, respectively). Both therapies increased body mass index after 1 y of treatment (0.9 and 0.8 kg/m2, respectively). Only rosiglitazone increased high-density lipoprotein cholesterol concentrations (0.1 mmol/L). Four patients (7.1%) who were given rosiglitazone developed adverse effects (2, ankle edema, and 2, gastrointestinal disturbance). Six insulin-treated patients (10.7%) described adverse effects (5, early morning hypoglycemia, and 1, anxiety). Investigators concluded that in Chinese patients with type 2 diabetes and secondary conventional OAD failure, 1 y of treatment with rosiglitazone or bedtime insulin added to the regular regimen resulted in similar improvements in glycemic control. Rosiglitazone was also associated with improved high-density lipoprotein cholesterol levels. The addition of rosiglitazone may offer a safe and effective alternative to bedtime insulin treatment.

Metabolic Syndrome May Not Associate With Carotid Plaque in Subjects With Optimal, Normal, or High-Normal Blood Pressure

Much evidence indicates that metabolic syndrome is a risk factor for the development of cardiovascular disease, but whether metabolic syndrome is an independent risk factor for early atherosclerosis in the individuals with only minor hemodynamic abnormalities, if any, is not well investigated. Here we have investigated the association between metabolic syndrome and carotid atherosclerosis in individuals with blood pressure of <140/90 mm Hg. Between 1994 and 2003, 8143 subjects underwent general health screening including carotid ultrasonography. Of 8143 individuals, 5661 individuals without antihypertensive medications who had blood pressure of <140/90 mm Hg were considered to have optimal, normal, or high-normal blood pressure. After adjustment for age, systolic blood pressure, body mass index, total and high-density lipoprotein cholesterol, triglycerides, fasting glucose, and smoking status, metabolic syndrome was not found to be an independent risk factor for carotid plaque (odds ratio: 1.65; 95% CI; 0.72 to 3.76 in women and odds ratio: 0.95; 95% CI: 0.70 to 1.28 in men) or for carotid intima-media thickening (odds ratio: 0.56; 95% CI: 0.18 to 1.72 in women and odds ratio: 0.93 95% CI: 0.62 to 1.38 in men) in these subjects. Thus, presence of metabolic syndrome may not increase the prevalence of carotid atherosclerosis independent of other cardiovascular risk factors in Japanese individuals with optimal, normal, or high-normal blood pressure.

Homocysteine and other biochemical parameters in Type 2 diabetes mellitus with different diabetic duration or diabetic retinopathy

BACKGROUND

Cardiovascular risk-related markers in type 2 diabetes mellitus (DM) have not been well understood.

METHODS

Serum and urine samples for biochemical and immunologic analysis were collected from 204 normal subjects and 257 type 2 DM patients, the latter of which were further classified by different diabetic duration with or without retinopathy.

RESULTS

Glycosylated hemoglobin A1c, triglyceride, lipase, free fatty acid, albumin creatinine ratio (ACR), lactate dehydrogenase (LDH) and homocysteine were significantly increased in DM patients, whereas high density lipoprotein cholesterol and bilirubin were significantly decreased in DM patients, compared with normal subjects. Lipid profiles, ACR, bilirubin, uric acid, creatine kinase, and hsCRP were not changed in DM patients with different diabetic duration or diabetic retinopathy. Lactate dehydrogenase in DM patients with duration >20 years and homocysteine in patients with duration >10 years was significantly higher than those with duration <5 years. Homocysteine was significantly increased in DM patients with retinopathy, compared with DM patients without retinopathy.

CONCLUSION

The increased triglyceride, lipase, free fatty acid, albumin creatinine ratio, lactate dehydrogenase and homocysteine as well as decreased high density lipoprotein cholesterol and anti-oxidative bilirubin in DM patients should be cautious and considered as risks for increasing DM complication. Homocysteine might be associated with longer diabetic duration and microvascular complication of retinopathy in diabetes.

Cardiovascular effects of the thiazolidinediones

Thiazolidinediones, used for the treatment of diabetes mellitus type 2, modulate gene expression by binding to nuclear transcription factor, peroxisome proliferator-activated receptor-gamma. Peroxisome proliferator-activated receptor-gamma is expressed in several tissues, therefore, thiazolidinediones have biological effects on multiple organ systems. Here, we describe evidence that thiazolidinediones have beneficial effects on the cardiovascular system independent of their antidiabetic effect. Studies in animals have clearly shown that thiazolidinediones decrease blood pressure, left ventricular hypertrophy, development of atherosclerotic lesions, and protect myocardium from ischemia/reperfusion injury. Although relatively few studies in humans have been reported, the preponderance of available evidence suggests a beneficial effect of thiazolidinediones. Thus, by modulating gene expression, thiazolidinediones may provide a novel method for the prevention and treatment of cardiovascular diseases.

Lipid and lipoprotein dysregulation in insulin resistant states

Insulin resistant states are commonly associated with an atherogenic dyslipidemia that contributes to significantly higher risk of atherosclerosis and cardiovascular disease. Indeed, disorders of carbohydrate and lipid metabolism co-exist in the majority of subjects with the "metabolic syndrome" and form the basis for the definition and diagnosis of this complex syndrome. The most fundamental defect in these patients is resistance to cellular actions of insulin, particularly resistance to insulin-stimulated glucose uptake. Insulin insensitivity appears to cause hyperinsulinemia, enhanced hepatic gluconeogenesis and glucose output, reduced suppression of lipolysis in adipose tissue leading to a high free fatty acid flux, and increased hepatic very low density lipoprotein (VLDL) secretion causing hypertriglyceridemia and reduced plasma levels of high density lipoprotein (HDL) cholesterol. Although the link between insulin resistance and dysregulation of lipoprotein metabolism is well established, a significant gap of knowledge exists regarding the underlying cellular and molecular mechanisms. Emerging evidence suggests that insulin resistance and its associated metabolic dyslipidemia result from perturbations in key molecules of the insulin signaling pathway, including overexpression of key phosphatases, downregulation and/or activation of key protein kinase cascades, leading to a state of mixed hepatic insulin resistance and sensitivity. These signaling changes in turn cause an increased expression of sterol regulatory element binding protein (SREBP) 1c, induction of de novo lipogensis and higher activity of microsomal triglyceride transfer protein (MTP), which together with high exogenous free fatty acid (FFA) flux collectively stimulate the hepatic production of apolipoprotein B (apoB)-containing VLDL particles. VLDL overproduction underlies the high triglyceride/low HDL-cholesterol lipid profile commonly observed in insulin resistant subjects.

Effects of fluvastatin slow-release (XL 80 mg) versus simvastatin (20 mg) on the lipid triad in patients with type 2 diabetes

The lipid triad is the association of small, dense (sd) low-density lipoprotein (LDL), low high-density lipoprotein (HDL), and hypertriglyceridemia, all of which play a role in coronary artery disease in patients with type 2 diabetes. Although statins have demonstrated clear positive effects on cardiovascular morbidity/mortality in patients with diabetes and on single components of the lipid triad, it remains controversial whether they affect all components of the triad in these patients. Therefore, we performed a single-center, parallel-group, prospective, randomized, open-label, blinded-endpoint (PROBE)-type comparison of fluvastatin extended-release (XL) 80 mg (n=48) and simvastatin 20 mg (n=46), each given once daily for 2 months to patients with type 2 diabetes with the lipid triad, who were enrolled after a 1-month lifestyle modification and dietary intervention program. After fluvastatin therapy, LDL (-51%; P<.01), apolipoprotein B (ApoB; -33%; P<.01), intermediate-density LDL (idLDL) (-14.3%; P<.05), sdLDL (-45%; P<.01), and triglycerides (-38%; P<.01) were significantly decreased, and HDL (+14.3%; P<.05) and apolipoprotein A-I (ApoA-I; +7%; P<.05) were increased; large buoyant (lb) LDL did not change (P=NS). Simvastatin therapy decreased LDL (-55.1%; P<.01), ApoB (-46%; P<.01), lbLDL (-33.3%; P<.05), idLDL (-22.7%; P<.05), sdLDL (-33.3%; P<.05), and triglycerides (-47.9%; P<.01); HDL was not changed (P=NS) after simvastatin, but ApoA-I was increased (+11.3%; P<.01). HDL increases (P<.01) and sdLDL decreases (P<.01) were significantly greater after fluvastatin compared with simvastatin therapy; LDL, triglycerides, ApoB, and idLDL changes were similar after both therapies (P=NS), and lbLDL decreases were greater with simvastatin therapy (P<.05). With both treatments, classic mean LDL and ApoB target levels were achieved in most patients. We conclude that the lipid triad can be controlled with fluvastatin XL 80 mg in patients with type 2 diabetes.

Association between cigarette smoking, metabolic syndrome, and carotid arteriosclerosis in Japanese individuals

Cigarette smoking is associated with increased insulin resistance and other metabolic abnormalities. Here, we investigate the prevalence of metabolic syndrome (MetS) in cigarette smokers and people who never smoked by analyzing cross-sectional data of 5033 subjects aged between 35 and 65 years who underwent general health screening. Both former and current smoking was associated with an increased incidence of metabolic syndrome defined by modified-National Cholesterol Education Program (NCEP) criteria with odds ratios of 1.77 (95% CI 1.42-2.22, P < 0.0001) and 2.38 (95% CI 1.95-2.91, P < 0.0001), respectively. In both former and current smokers, prevalence of metabolic syndrome increased when the duration of cigarette smoking was > or = 10 years. The positive association between metabolic syndrome and smoking was only partially reversed even 5 years after quitting. Multivariate logistic regression analysis showed that metabolic syndrome was an independent risk factor for carotid plaque with an odds ratio of 1.72 (95% CI 1.43-2.08, P < 0.0001). On the other hand, when limited to individuals without metabolic syndrome, former and current smoking was still found to be associated with carotid plaque with odds ratios of 1.49 (95% CI 1.15-1.92, P = 0.0023) and 1.57 (95% CI 1.22-2.03, P = 0.0005), respectively, in men. Collectively, these data suggest that the atherogenic consequences of smoking may, at least in part, be explained by its association with metabolic syndrome.

Pioglitazone in a subgroup of patients with type 2 diabetes meeting the criteria for metabolic syndrome

Pioglitazone monotherapy and combinations were assessed in patients with type 2 diabetes and metabolic syndrome (Adult Treatment Panel III criteria) from four worldwide randomised, multicentre, double-blind studies. Patients were treated for 52 weeks with pioglitazone (PIO, n = 1040), sulphonylurea (SU, n = 535) or metformin (MET, n = 500) PIO + SU (n = 277) or MET + SU (n = 273); or PIO + MET (n = 286) or SU + MET (n = 275). Pooled week 52 glycaemic and lipid changes were compared using analysis of covariance. Haemoglobin A(1c) decreased significantly with pioglitazone compared with sulphonylurea (p < 0.05). Fasting, 2- and 3-h plasma glucose, insulin and homeostasis model assessment for insulin resistance decreased significantly with pioglitazone compared with other monotherapies (p < 0.05) and decreased significantly with PIO + MET compared with SU + MET (p < 0.05). Pioglitazone, alone and with metformin, improved lipid components of diabetic dyslipidaemia more than did their respective comparison groups. Pioglitazone was associated with weight increase. In conclusion, pioglitazone provided effective glycaemic control and lipid profile improvements in patients with type 2 diabetes and metabolic syndrome.

Diabetic cardiomyopathy: mechanisms, diagnosis and treatment

Independent of the severity of coronary artery disease, diabetic patients have an increased risk of developing heart failure. This clinical entity has been considered to be a distinct disease process referred to as 'diabetic cardiomyopathy'. Experimental studies suggest that extensive metabolic perturbations may underlie both functional and structural alterations of the diabetic myocardium. Translational studies are, however, limited and only partly explain why diabetic patients are at increased risk of cardiomyopathy and heart failure. Although a range of diagnostic methods may help to characterize alterations in cardiac function in general, none are specific for the alterations in diabetes. Treatment paradigms are very much limited to interpretation and translation from the results of interventions in non-diabetic patients with heart failure. This suggests that there is an urgent need to conduct pathogenetic, diagnostic and therapeutic studies specifically in diabetic patients with cardiomyopathy to better understand the factors which initiate and progress diabetic cardiomyopathy and to develop more effective treatments.

Hypertension Is the Most Common Component of Metabolic Syndrome and the Greatest Contributor to Carotid Arteriosclerosis in Apparently Healthy Japanese Individuals

The cluster of metabolic and hemodynamic risk factors known as metabolic syndrome is known to be a risk factor for ischemic cardiovascular diseases and stroke. By analyzing the cross-sectional data from 8,144 individuals (age 19-88 years) who underwent general health screening, we have investigated the prevalence of metabolic syndrome, as diagnosed by modified-National Cholesterol Education Program (NCEP) criteria corresponding to the following five categories: triglycerides > or = 150 mg/dl; high density lipoprotein (HDL)-cholesterol < 40 mg/dl in men or < 50 mg/dl in women; fasting plasma glucose > or = 110 mg/dl; systolic/diastolic blood pressure > or = 130/85 mmHg; and body mass index > 25 kg/m2. We found that the prevalence of metabolic syndrome was 19% in men and 7% in women. After adjustment for age, metabolic syndrome was found to be significantly more prevalent in men than in women, with an odds ratio of 3.08 (95% confidence interval [CI] 2.62-3.61, p < 0.0001). Among the five metabolic/hemodynamic risk factor components, hypertension was observed most frequently in individuals with metabolic syndrome, at 85% in men and 87% in women. In addition, multivariate logistic regression analysis adjusted for age, sex, serum total cholesterol levels, and smoking status showed that hypertension possessed the greatest odds ratio (1.43, 95% CI 1.27-1.60) for carotid plaque among the metabolic/hemodynamic risk factors. These data emphasize the importance of controlling blood pressure for reducing the risk of both metabolic syndrome and carotid arteriosclerosis in apparently healthy individuals.

Diabetes and cardiovascular risk markers

BACKGROUND

People with type 2 diabetes generally carry an array of risk factors for cardiovascular disease (CVD), including hyperglycaemia, dyslipidaemia, alterations in inflammatory mediators and coagulation/thrombolytic parameters, as well as other 'non-traditional' risk factors, many of which may be closely associated with insulin resistance. Consequently, rates of CVD mortality and morbidity are particularly high in this population. Targeting hyperglycaemia alone does not reduce the excess risk in diabetes, highlighting the need for aggressive treatment of other risk factors.

SCOPE

This is a review of cardiovascular risk markers in diabetes, based on MEDLINE and EMBASE literature searches (1994-2004).

FINDINGS

Although, the current use of statin therapy is effective at reducing low-density lipoprotein (LDL)-cholesterol, residual risk remains from other independent lipid and non-lipid factors. The peroxisome proliferator-activated receptor-gamma(PPARgamma) appears to be intimately involved in regulating risk markers at multiple levels. Ligands that activate PPARgamma, which include the thiazolidinedione (TZD) insulin-sensitizing agents used to manage type 2 diabetes, display a number of potential anti-atherogenic properties, including effects on high-density lipoprotein (HDL) cholesterol and triglycerides, as well as other beneficial non-lipid effects, such as regulating levels of mediators involved in inflammation and endothelial dysfunction. Data from several sources suggest that simple strategies combining TZDs and statins could have complementary effects on CVD risk factors profiles in diabetes, alongside the ability to control glycaemia.

CONCLUSION

It is hoped that studies currently underway will provide insights into the value of such treatment approaches in terms of reducing the excess CVD risk, morbidity and mortality associated with type 2 diabetes.