Coronary artery disease (CAD) is a major vascular complication of diabetes mellitus and reveals high mortality. Up to 30% of diabetic patients with myocardial ischemia remain asymptomatic and are associated with worse prognosis compared to non-diabetic counterpart, which warrants routine screening for CAD in diabetic population. The purpose of this study was to evaluate the clinical value of serum glycated albumin and high-sensitivity C-reactive protein (hs-CRP) levels in predicting the presence of CAD in patients with type 2 diabetes.
Three hundred and twenty-four patients with type 2 diabetes were divided into two groups based on presence (CAD group, n = 241) or absence (control group, n = 83) of angiographically-documented CAD (lumen diameter narrowing ≥70%). Serum levels of glycated albumin and hs-CRP as well as serum concentrations of glucose, lipids, creatinine, blood urea nitrogen and uric acid were measured in both groups. Predictors of CAD were determined using multivariate logistic regression model and receiver-operating characteristic (ROC) curves.
Serum glycated albumin and hs-CRP levels were significantly increased in diabetic patients with CAD. Multivariate regression analysis revealed that male gender, age, serum levels of glycated albumin, hs-CRP, creatinine and lipoprotein (a) were independent predictors for CAD. Areas under the curve of glycated albumin and hs-CRP and for regression model were 0.654 (95%CI 0.579–0.730, P < 0.001), 0.721 (95%CI 0.658–0.785, P < 0.001) and 0.824 (95% CI 0.768–0.879, P < 0.001), respectively. The optimal values of cut-off point were 18.7% (sensitivity 67.9%, specificity 60.0%) for glycated albumin and 5.2 mg/l (sensitivity 72.2%, specificity 60.0%) for hs-CRP to predict CAD. Logistic regression model was defined as: P/(1-P) = EXP(-1.5 + 1.265 gender + 0.812 age + 1.24 glycated albumin + 0.953 hs-CRP + 0.902 lipoprotein(a) + 1.918 creatinine). The optimal probability value for predicting CAD in type 2 diabetic patients was 0.648 (sensitivity 82.3%, specificity 68.6%).
Serum glycated albumin and hs-CRP levels were significantly elevated in patients with type 2 diabetes and CAD. The logistic regression model incorporating with glycated albumin, hs-CRP and other major risk factors of atherosclerosis may be useful for screening CAD in patients with type 2 diabetes.
In spite of a large amount of studies in anesthetized animals, isolated hearts, and in vitro cardiomyocytes, to our knowledge, myocardial function was never studied in conscious diabetic rats. Myocardial performance and the response to stress caused by dobutamine were examined in conscious rats, fifteen days after the onset of diabetes caused by streptozotocin (STZ). The protective effect of insulin was also investigated in STZ-diabetic rats.
Cardiac contractility and relaxation were evaluated by means of maximum positive (+dP/dtmax) and negative (-dP/dtmax) values of first derivative of left ventricular pressure over time. In addition, it was examined the myocardial response to stress caused by two dosages (1 and 15 μg/kg) of dobutamine. One-way analysis of variance (ANOVA) was used to compare differences among groups, and two-way ANOVA for repeated measure, followed by Tukey post hoc test, to compare the responses to dobutamine. Differences were considered significant if P < 0.05.
Basal mean arterial pressure, heart rate, +dP/dtmax and -dP/dtmax were found decreased in STZ-diabetic rats, but unaltered in control rats treated with vehicle and STZ-diabetic rats treated with insulin. Therefore, insulin prevented the hemodynamic and myocardial function alterations observed in STZ-diabetic rats. Lower dosage of dobutamine increased heart rate, +dP/dtmax and -dP/dtmax only in STZ-diabetic rats, while the higher dosage promoted greater, but similar, responses in the three groups. In conclusion, the results indicate that myocardial function was remarkably attenuated in conscious STZ-diabetic rats. In addition, the lower dosage of dobutamine uncovered a greater responsiveness of the myocardium of STZ-diabetic rats. Insulin preserved myocardial function and the integrity of the response to dobutamine of STZ-diabetic rats.
The present study provides new data from conscious rats showing that the cardiomyopathy of this pathophysiological condition was expressed by low indices of contractility and relaxation. In addition, it was also demonstrated that these pathophysiological features were prevented by the treatment with insulin.
The metabolic syndrome together with insulin resistance and their consequences are basic factors in pathogenesis of atherosclerosis. Chronic infections with herpes simplex virus type 1 (HSV-1), cytomegalovirus (CMV), and Chlamydia pneumoniae are associated with the development of atherosclerosis and coronary heart disease. The infectious aspects of metabolic syndrome have not been investigated.
In a cross-sectional, population-based study, we used National Cholesterol Education Program (NCEP)-Adult Treatment Panel (ATP)-III criteria in 1791 subjects, aged 25 years and over, selected by cluster random sampling in three Iranian ports in the northern Persian Gulf. Sera were analyzed for IgG antibodies to Chlamydia pneumoniae, HSV-1, Helicobacter pylori (H. pylori) and CMV using ELISA.
In multiple logistic regression analysis, of the infectious agents, CMV [OR = 1.81 (1.05–3.10); p = 0.03], H. pylori [OR = 1.50 (1.12–2.00); p = 0.007] and Chlamydia pneumoniae [OR = 1.69 (1.27–2.25); p < 0.0001] showed a significant association with the metabolic syndrome in men and HSV-1 [OR = 1.95 (1.22–3.11); p = 0.005], H. pylori [OR = 1.45 (1.09–1.94); 0.01] and Chlamydia pneumoniae [OR = 1.65 (1.23–2.21); p = 0.001] in women.
The metabolic syndrome, which occurs very frequently in the general population, has a significant association with prior infection with Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus and herpes simplex virus type 1. Hypothesis about participation of infection in pathogenesis of metabolic syndrome should be investigated.
The metabolic syndrome appears to affect 10% to 25% of adult population worldwide. Several studies have described the association between metabolic syndrome and ischaemic heart disease, however, none linked metabolic syndrome to ischemic mitral regurgitation, a serious clinical problem facing both the cardiologists and cardiac surgeons. Ischemic mitral regurgitation is mitral insufficiency caused by myocardial infarction. The myocardial ischemia can result in altered ventricular geometry, leading to mitral insufficiency. Interestingly metabolic syndrome showed more pronounced alteration of left ventricular geometry and function especially in obese subjects.
Presentation of the hypothesis
We have recently proposed that there is link between metabolic syndrome and ischemic mitral regurgitation and associated complications. Operative strategy for moderate ischaemic mitral regurgitation continues to be debated between revascularisation alone and concomitant valve repair at the time of coronary artery bypass surgery. Each of the above group has published studies, with results supporting each argument.
Testing the hypothesis
Generally speaking the treatments available for metabolic syndrome are based in both life style modification (dietary advice and advice to increase physical activity) and medical treatment to enhance insulin sensitivity. Randomised controlled trials may show whether the current available treatment of metabolic syndrome may have an impact on moderate ischemic mitral regurgitation.
Implications of the hypothesis
Metabolic syndrome was shown to alter left ventricular geometry and therefore it is possible to postulate that the variation in the response of different patients with moderate ischemic mitral regurgitation to current management may be attributed to the absence and presence of metabolic syndrome. Research testing of this hypothesis in the future may reveal whether concomitant treatment of metabolic syndrome will play part in the management of moderate ischemic mitral regurgitation.
Target organ damage (mainly cardiac and renal damage) is easy to evaluate in outpatient clinics and offers valuable information about patient's cardiovascular risk. The purpose of this study was to evaluate, using simple methods, the prevalence of cardiac and renal damage and its relationship to the presence of established cardiovascular disease (CVD), in patients with hypertension (HT) and type 2 diabetes mellitus (DM).
The RICARHD study is a multicentre, cross-sectional study made by 293 investigators in Nephrology and Internal Medicine Spanish outpatient clinics, and included patients aged 55 years or more with HT and type 2 DM with more than six months of diagnosis. Demographic, clinical and biochemical data, and CVD were collected from the clinical records. Cardiac damage was defined by the presence of electrocardiographic left ventricular hypertrophy (ECG-LVH), and renal damage by a calculated glomerular filtration rate (GFR) of <60 ml/min/1.73 m2, and/or the presence of an albumin/creatinine ratio ≥ 30 mg/g; or an urinary albumin excretion (UAE) ≥ 30 mg/24 hours.
2339 patients (mean age 68.9 years, 48.2% females, 51.3% with established CVD) were included. ECG-LVH was present in 22.9% of the sample, GFR <60 ml/min/1.73 m2 in 45.1%, and abnormal UAE in 58.7%. Compared with the reference patients (those without neither cardiac nor renal damage), patients with ECG-LVH alone (OR 2.20, [95%CI 1.43–3.38]), or kidney damage alone (OR 1.41, [1.13–1.75]) showed an increased prevalence of CVD. The presence of both ECG-LVH and renal damage was associated with the higher prevalence (OR 3.12, [2.33–4.19]). After stratifying by gender, this relationship was present for both, men and women.
In patients with HT and type 2 DM, ECG-LVH or renal damage, evaluated using simple methods, are associated with an increased prevalence of established CVD. The simultaneous presence of both cardiac and renal damage was associated to the higher prevalence of CVD, affording complementary information. A systematic assessment of cardiac and renal damage complements the risk assessment of these patients with HT and type 2 DM.
Obstructive sleep apnoea (OSA) is a cardio-metabolic disorder. Whether metabolic syndrome (MS), insulin resistance (IR) and albuminuria are independently associated with OSA is unclear, but defining the interactions between OSA and various cardiovascular (CV) risk factors independent of obesity facilitates the development of therapeutic strategies to mitigate their increased CV risks. We prospectively recruited 38 subjects with OSA and 41 controls. Anthropometric measurements, glucose, lipids, insulin and blood pressure (BP) were measured after an overnight fast. IR state was defined as homeostasis model assessment (HOMA) value >3.99 and MS diagnosed according to the International Diabetes Federation (IDF) criteria. Subjects with OSA were more obese, more insulin resistant, more hyperglycaemic, had higher Epworth score (measure of day time somnolence) and systolic blood pressure levels. The prevalence of MS was higher in OSA compared with non-OSA subjects (74% vs 24%, p < 0.001). The prevalence of microalbuminuria in both groups was negligible. Logistic regression adjusted for age, BMI and smoking showed that the patient with OSA was 5.9 (95% CI 2.0–17.6) times more likely to have MS than non-OSA patient. Triglyceride (p = 0.031), glucose (0.023) and Epworth score (0.003) values were independently associated with OSA after adjusting for BMI and other covariates whilst IR status was found not to be significant. Using the ROC curve analysis, we found that a waist circumference of >103 cm would predict MS in patients with OSA at 75–78% sensitivity and 61–64% specificity. The agreement between MS and IR state in this cohort is poor. Thus, OSA is associated with MS independent of obesity predominantly due to increased triglyceride, glucose and Epworth score values but not IR or microalbuminuria status. This observation suggests an alternative pathogenic factor mediating the increased cardiovascular risk in patients with OSA and MS, other than that due to IR. The independent link between Epworth score and MS in patients with OSA implicates the role of daytime sleepiness and chronic hypoxia as a potential mediator. Given the discordant between MS and IR state, measurement of waist is useful for predicting mainly MS but not insulin resistance status in patients with OSA. Appropriate pharmacological intervention targeting these independent factors is important in reducing the increased CV risks among patients with OSA.
Patients with diabetes already fulfill one diagnostic criterion for MS according to the existing classifications. Our aim was to identify one single clinical parameter, which could effectively predict the presence of MS in patients with type 2 diabetes.
We studied all patients with type 2 diabetes who attended our Diabetes Outpatient Clinic during a three-month period. Waist circumference, blood pressure and serum lipids were measured. Establishment of MS diagnosis was based a) on National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria and b) on International Diabetes Federation (IDF) criteria. Receiver operating characteristic (ROC) analysis was applied in order to identify the clinical parameter with the highest predictive capability for MS. Among the 500 participating patients (231 males, 269 females), MS was diagnosed in 364 patients (72.8%) according to the NCEP ATP III criteria and in 408 patients (81.6%) according to the IDF criteria.
For the NCEP ATP III classification, serum triglycerides (in the overall population), waist and HDL (in female population) demonstrated the highest predictive capability for MS (AUCs:0.786, 0.805 and 0.801, respectively). For the IDF classification, no single parameter reached an AUC > 0.800 in the overall population. In females, HDL displayed a satisfactory predictive capability for MS with an AUC which was significantly higher than the one in males (0.785 vs. 0.676, respectively, p < 0.05).
Elevated serum triglycerides strongly indicate the presence of MS in patients with type 2 diabetes. In female patients with type 2 diabetes, central obesity was the second stronger predictor of MS besides hypertriglyceridemia.
Lowering of low-density lipoprotein cholesterol with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) is clearly efficacious in the treatment and prevention of coronary artery disease. However, despite increasing use of statins, a significant number of coronary events still occur and many of such events take place in patients presenting with type 2 diabetes and metabolic syndrome. More and more attention is being paid now to combined atherogenic dyslipidemia which typically presents in patients with type 2 diabetes and metabolic syndrome. This mixed dyslipidemia (or "lipid quartet"): hypertriglyceridemia, low high-density lipoprotein cholesterol levels, a preponderance of small, dense low-density lipoprotein particles and an accumulation of cholesterol-rich remnant particles (e.g. high levels of apolipoprotein B) – emerged as the greatest "competitor" of low-density lipoprotein-cholesterol among lipid risk factors for cardiovascular disease. Most recent extensions of the fibrates trials (BIP – Bezafibrate Infarction Prevention study, HHS – Helsinki Heart Study, VAHIT – Veterans Affairs High-density lipoprotein cholesterol Intervention Trial and FIELD – Fenofibrate Intervention and Event Lowering in Diabetes) give further support to the hypothesis that patients with insulin-resistant syndromes such as diabetes and/or metabolic syndrome might be the ones to derive the most benefit from therapy with fibrates. However, different fibrates may have a somewhat different spectrum of effects. Other lipid-modifying strategies included using of niacin, ezetimibe, bile acid sequestrants and cholesteryl ester transfer protein inhibition. In addition, bezafibrate as pan-peroxisome proliferator activated receptor activator has clearly demonstrated beneficial pleiotropic effects related to glucose metabolism and insulin sensitivity. Because fibrates, niacin, ezetimibe and statins each regulate serum lipids by different mechanisms, combination therapy – selected on the basis of their safety and effectiveness – may offer particularly desirable benefits in patients with combined hyperlipidemia as compared with statins monotherapy.
The aim of this study was to determine if hypertensive type 2 diabetic patients, when compared to patients with essential hypertension have an increased left ventricular mass index (LVMI) and a worse diastolic function, and if this fact would be related to 24-h pressoric levels changes.
Ninety-one hypertensive patients with type 2 diabetes mellitus (DM) (group-1 [G1]), 59 essential hypertensive patients (group-2 [G2]) and 26 healthy controls (group-3 [G3]) were submitted to 24-h Ambulatory Blood Pressure Monitoring (ABPM) and echocardiography (ECHO) with Doppler. We calculated an average of fasting blood glucose (AFBG) values of G1 from the previous 4.2 years and a glycemic control index (GCI) (percentual of FBG above 200 mg/dl).
G1 and G2 did not differ on average of diurnal systolic and diastolic BP. However, G1 presented worse diastolic function and a higher average of nocturnal systolic BP (NSBP) and LVMI (NSBP = 132 ± 18 vs 124 ± 14 mmHg; P < 0.05 and LVMI = 103 ± 27 vs 89 ± 17 g/m2; P < 0.05, respectively). In G1, LVMI correlated with NSBP (r = 0.37; P < 0.001) and GCI (r = 0.29; P < 0.05) while NSBP correlated with GCI (r = 0.27; P < 0.05) and AFBG (r = 0.30; P < 0.01). When G1 was divided in tertiles according to NSBP, the subgroup with NSBP≥140 mmHg showed a higher risk of LVH. Diabetics with NSBP≥140 mmHg and AFBG>165 mg/dl showed an additional risk of LVH (P < 0.05; odds ratio = 11). In multivariate regression, both GCI and NSBP were independent predictors of LVMI in G1.
This study suggests that hyperglycemia and higher NSBP levels should be responsible for an increased prevalence of LVH in hypertensive patients with Type 2 DM.
Diabetes mellitus is an important risk factor for increased vein graft failure after bypass surgery. However, the cellular and molecular mechanism(s) underlying vessel attrition in this population remain largely unexplored. Recent reports have suggested that the pathological remodeling of vein grafts may be mediated by mechanically-induced activation of the mitogen activated protein kinase (MAPK) signaling pathways and the MAPK-related induction of caspase-3 activity. On the basis of these findings, we hypothesized that diabetes may be associated with alterations in how veins "sense" and "respond" to altered mechanical loading.
Inferior venae cavae (IVC) from the non-diabetic lean (LNZ) and the diabetic obese (OSXZ) Zucker rats were isolated and incubated ex vivo under basal or pressurized conditions (120 mmHg). Protein expression, basal activation and the ability of increased pressure to activate MAPK pathways and apoptosis-related signaling was evaluated by immunoblot analysis.
Immunoblot analyses revealed differential expression and activation of extracellular signal-regulated kinase (ERK1/2), p38 and c-Jun NH2-terminal kinase (JNK) MAPKs in the IVCs of diabetic rats as compared to non-diabetic rats. In particular, the expression and basal phosphorylation of p38β- (52.3 ± 11.8%; 45.8 ± 18.2%), JNK 1- (21.5 ± 9.3%; 19.4 ± 11.6%) and JNK3-MAPK (16.8 ± 3.3%; 29.5 ± 17.6%) were significantly higher (P < 0.05) in the diabetic vena cava. An acute increase in IVC intraluminal pressure failed to increase the phosphorylation of ERK1-, JNK-2, or any of the p38-MAPKs in the diabetic obese Zucker rats. Also, IVC loading in the LNZ led to a 276.0 ± 36.0% and 85.8 ± 25.1% (P < 0.05) increase in the cleavage of caspase-3 and caspase-9, respectively, with no effect on these molecules in the OSXZ. No differences were found in the regulation of Bax and Bcl-2 between groups. However, basal expression levels of Akt, phospho-Akt, PTEN, phospho-PTEN and phospho-Bad were higher in the diabetic venae cavae (P < 0.05).
These data suggest that diabetes is associated with significant alteration in the ability of the vena cava to activate MAPK- and apoptosis-related signaling. Whether these changes are associated with the increased vein graft attrition seen in the diabetic population will require further investigation.
Systemic adiponectin is reduced in patients with cardiovascular disease (CVD) and low adiponectin may contribute to the pathogenesis of atherosclerosis. However, circulating adiponectin is elevated in type 1 diabetes (T1D) patients, who have also a higher incidence to develop CVD. Because monocytes play an important role in atherosclerosis, we analysed the influence of adiponectin on cytokine and chemokine release in monocytes from T1D patients and controls.
Systemic adiponectin was determined in the plasma and the high-molecular weight (HMW) form of adiponectin was analysed by immunoblot. Monocytes were isolated from T1D patients and controls and the adiponectin-stimulated release of interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1, CCL2) and interleukin-8 (IL-8, CXCL8) was analysed.
Systemic adiponectin was higher in T1D patients. Immunoblot analysis of the plasma indicate abundance of HMW adiponectin in T1D patients and controls. IL-6, CCL2 and CXCL8 secretion in response to adiponectin were found induced in monocytes from controls whereas only IL-6 was upregulated in T1D cells. The induction of IL-6 by adiponectin was abrogated by an inhibitor of the NFκB pathway.
These data indicate that adiponectin-mediated induction of IL-6, CCL2 and CXCL8 is disturbed in monocytes from T1D patients and therefore elevated systemic adiponectin in T1D patients may be less protective when compared to controls.
Secondary treatment of arteriosclerosis may be applicable for the primary prevention of atherosclerosis in diabetic patients. This prospective, 2-year follow-up study was designed to determine the efficacy and safety of antiplatelet therapy in the prevention of atherosclerosis of diabetic subjects.
Patients with type 2 diabetes and arteriosclerosis obliterans from the Eastern Asian countries were registered online and randomly assigned either to the aspirin group (81–100 mg/day) or the cilostazol group (100–200 mg/day) in this international, 2-year, prospective follow-up interventional study.
The primary study endpoint was changes in right and left maximum intima-media thickness of the common carotid artery. Secondary endpoints include changes in right and left maximum intima-media thickness of the internal carotid artery; semiquantitative evaluation of cerebral infarction by magnetic resonance imaging; cardiovascular events including sudden death, stroke, transient cerebral ischemic attacks, acute myocardial infarction, angina, and progression of arteriosclerosis obliterans; overall death; withdrawal; and change in ankle-brachial pressure index.
This is the first study to use an online system that was developed in Asian countries for pooling data from an international clinical trial. These findings are expected to help in the prevention of diabetic atherosclerosis and subsequent cardiovascular and cerebrovascular disease.
Coronary artery disease is the leading cause of death in industrialized countries and most patients with diabetes die from complications of atherosclerosis. The objective of this study was to determine the presence of diabetes mellitus and other conventional coronary heart disease risk factors (cigarette smoking, hypertension and hyperlipidemia) in patients with acute coronary events in an Iranian population.
The study included 514 patients with unstable angina or myocardial infarction (MI) out of 720 patients admitted to CCU ward of a general hospital from March 2003 to March 2005. History of diabetes, hypertension and cigarette smoking, demographic indices, coronary heart disease and diabetes mellitus treatment, myocardial enzymes, serum triglycerides (TG) and cholesterol and fasting and non fasting blood glucose levels and HbA1C of diabetics were recorded of admission sheets. The data were structured to appropriate one way ANOVA, T tests, and chi square test with SPSS 13 product for windows.
Out of all patients 35.8% were female, 30% were diabetics (Duration 13.4 ± 8.7 years), 42% were smoker and 91% were hypertensive. Twenty four percent had MI and 76% had unstable angina. MI was significantly higher in diabetic patients (36.4% vs. 19.2%, P < 0.001). Location and extension of MI and myocardial enzymes did not differ between diabetics and non-diabetic patients. Diabetic patients were older than non diabetics (65 ± 11.6 vs. 59.7 ± 12.5 years, p < 0.05). Five (66.7%) out of 9 patients with fatal MI were diabetics (Odds Ratio = 2.98). Age, duration of diabetes and HbA1c levels, did not differ between diabetic patients with or without MI. Hypertension and current smoking was significantly higher in patients with MI compared to patients with unstable angina (p < 0.05). Serum TG, HDL-C, LDL-C and total cholesterol level did not differ between patients with MI and unstable angina. Diabetic patients compare to non diabetic patients were more hypertensive (96% vs. 88.7%, p < 0.005) and had higher serum triglyceride (TG over 200 mg/dl, 35.1% vs. 26.4, p <0.05). Diabetes was more frequent among women than men (36.4% vs. 26.4%, p < 0.05). Women were older than men (65 ± 11.6 vs. 59.2 ± 13 years, p < 0.005) and had higher total serum cholesterol (200 ± 41.8 vs. 192 ± 42.5 mg/dl, p < 0.05) and HDL-C levels (49.7 ± 22 vs. 40 ± 13 mg/dl, p < 0.005). Ninety seven percent of all patients had at least one of cardiovascular risk factors (hypertension, smoking, diabetes, high cholesterol and low HDL-cholesterol levels).
In this study 19 out of 20 patients with acute coronary event have at least one of conventional cardiac risk factors. Diabetes and hypertension are leading risk factors, which may directly or indirectly interfere and predict more serious complications of coronary heart disease.
Tumor necrosis factor-α (TNFα) is a mediator of insulin resistance. Plasma levels of soluble TNFα receptors (sTNFR1 and sTNFR2) probably reflect paracrine action of the cytokine. TNFα is also a regulator of lipid metabolism, however, data about impact of obesity on the relationships between TNFα and plasma lipids remain controversial.
The purpose of the present study was to examine the associations of TNFα system with plasma lipids in lean and obese subjects with normal glucose metabolism.
We examined 63 subjects, 33 lean (BMI<25 kg × m-2) and 30 with marked overweight or obesity (BMI>27.8 kg × m-2). Anthropometric and biochemical parameters were measured. Oral glucose tolerance test and euglycemic hyperinsulinemic clamp were also performed.
Obese subjects were markedly more insulin resistant and had higher levels of both TNFα receptors. Total (TC) and LDL-cholesterol (LDL-C), triglycerides (TG) and non-esterified fatty acids (NEFA) were also higher in the obese group. In obese subjects, both receptors were significantly related to TG and HDL-cholesterol (HDL-C), while sTNFR2 was also associated with NEFA. All those correlations disappeared after controlling for insulin sensitivity. In lean subjects, both receptors were related to TC, HDL-C and LDL-C. In that group, sTNFR1 predicted values of all those parameters independently of BMI, plasma glucose and insulin, and insulin sensitivity.
We conclude that TNFα receptors are associated with plasma lipids in different way in lean and in obese subjects. TNFα system is probably important in determining cholesterol levels in lean subjects, while in obese this effect might be masked by other metabolic abnormalities.
Foam cell formation in diabetic patients often occurs in the presence of high insulin and glucose levels. To test whether hyperinsulinemic hyperglycemic conditions affect foam cell differentiation, we examined gene expression, cytokine production, and Akt phosphorylation in human monocyte-derived macrophages incubated with two types of oxidized low density lipoprotein (LDL), minimally modified LDL (mmLDL) and extensively oxidized LDL (OxLDL).
Methods and results
Using Affymetrix GeneChip® arrays, we found that several genes directly related to insulin signaling were changed. The insulin receptor and glucose-6-phosphate dehydrogenase were upregulated by mmLDL and OxLDL, whereas insulin-induced gene 1 was significantly down-regulated. In hyperinsulinemic hyperglycemic conditions, modified LDL upregulated Akt phosphorylation and expression of the insulin-regulated aminopeptidase. The level of proinflammatory cytokines, IL-lβ, IL-12, and IL-6, and of a 5-lipoxygenase eicosanoid, 5-hydroxyeicosatetraenoic acid (5-HETE), was also increased.
These results suggest that the exposure of macrophages to modified low density lipoproteins in hyperglycemic hyperinsulinemic conditions affects insulin signaling and promotes the release of proinflammatory stimuli, such as cytokines and eicosanoids. These in turn may contribute to the development of insulin resistance.
There have been scant reports on the cumulative effects of atherosclerotic risk factors on steatohepatitis.
We defined cases of steatohepatitis (n = 124) from one health examination center at National Taiwan University Hospital from January to December 2002. We selected controls, matched by age, gender and drinking status. Metabolic syndrome was defined by the modified ATP-III guidelines. High-dimensional interactions of risk factors for steatohepatitis were evaluated.
Steatohepatitis cases had the highest C-reactive protein, lymphocytes, Framingham scores and predicted coronary risks. The odds ratio (OR) of metabolic syndrome for steatohepatitis was the highest (OR = 9.9), followed by high glucose status (OR = 4.5) and obesity (OR = 3.6). The highest area under the ROC curve was metabolic syndrome (area = 0.80), followed by obesity (0.75) and high glucose level (0.73). Metabolic syndrome was the highest population-attributable risk factor (0.59). Significant interaction was found with a three-factor model, including obesity, metabolic syndrome and Framingham risk status, with lesser average prediction error (22.6%), higher average cross-validation consistency (6.3) and lower average prediction error (24.3%). Compared with persons with no risk factors, OR increased as the number of risk factors increased (OR = 3.0 with one risk factor, 17.5 with two risk factors, 10.8 with three risk factors, respectively).
Metabolic syndrome, inflammation markers and atherosclerotic risk scores are significantly related to steatohepatitis status among the healthy examinee population in Taiwan.
Adiponectin acts as an antidiabetic, antiinflammatory and antiatherogenic adipokine. These effects are assumed to be mediated by the recently discovered adiponectin receptors AdipoR1 and AdipoR2.
The purpose of this study was to determine whether variations in the AdipoR1 and AdipoR2 genes may contribute to insulin resistance, dyslipidemia and inflammation.
We sequenced all seven coding exons of both genes in 20 unrelated German subjects with metabolic syndrome and tested genetic variants for association with glucose, lipid and inflammatory parameters.
We identified three AdipoR2 variants (+795G/A, +870C/A and +963C/T) in perfect linkage disequilibrium (r2 = 1) with a minor allele frequency of 0.125. This haplotype was associated with higher plasma adiponectin levels and decreased fasting triglyceride, VLDL-triglyceride and VLDL-cholesterol levels. No association, however, was observed between the AdipoR2 SNP cluster and glucose metabolism.
To our knowledge, this is the first study to identify an association between genetic variants of the adiponectin receptor genes and plasma adiponectin levels. Furthermore, our data suggest that AdipoR2 may play an important role in triglyceride/VLDL metabolism.
South-Asians have lower adiponectin levels compared to Caucasians. It was not clear however, if this intrinsic feature is related to aspects of glucose metabolism. This study aims to determine the relationship between body fat distribution and adipocytokine in South-Asian subjects by measuring serum adipocytokines, adiposity, insulinemia, and glucose tolerance levels.
In this cross-sectional study, 150 South-Asians (80 males, 70 females) were included, 60 had NGT (Control group, Age 51.33 ± 11.5, BMI 27 ± 2.3), 60 had IGT (Age 57.7 ± 12.5, BMI 27.2 ± 2.7), 30 had type 2 DM (Age 49.5 ± 10.9, BMI 28 ± 1.7). Measures of adiposity, adipocytokines and other metabolic parameters were determined. Parameters were measured using the following: a) Plasma glucose by glucose oxidase method b) CRP by immunoturbidimetric method (Roche/Hitachi analyser) c) insulin by Medgenix INS-ELISA immunoenzymetric assay by Biosource (Belgium) d) Leptin, Adiponectin by radioimmunoassay kits by Linco Research (St. Charles MO) e) Resistin by immunoassay kits by Phoenix Pharmaceuticals INC (530 Harbor Boulevard, Belmont CA 94002, USA).
Adiponectin concentrations were highest in NGT, decreased in IGT and lowest in DMT2, (both p < 0.01). Leptin was significantly higher in DMT2 than IGT and NGT p = 0.02 and 0.04 respectively. There was a significant positive relationships between log adiponectin and 2-hr insulin values, p = 0.028 and history of hypertensions and a ischemic heart disease p = 0.008 with R = 0.65. There was a significant inverse correlation between log adiponectin and resistin, p < 0.01.
Resistin levels had an inverse correlation with adiponectin levels, indicating an inverse relationship between pro-inflammatory cytokines and adiponectin. Adiponectin levels were related to glucose tolerance.
Impaired glucose tolerance (IGT) is associated with increased cardiovascular risk. The pathophysiological mechanisms linking post-challenge hyperglycemia to accelerated atherosclerosis, however remain to be elucidated.
A prospective, open, randomised, cross-over study was performed to investigate the effect of 2 mg repaglinide on hyperglycemia and endothelial function during an oral glucose tolerance test (75 g glucose) in 12 subjects with diagnosed IGT. Blood samples for determination of plasma glucose were drawn fasting, 1 and 2 hours after glucose ingestion. Endothelial function was assessed by measuring flow-mediated dilatation (FMD) of the brachial artery with high-resolution ultrasound.
Administration of repaglinide resulted in a significant reduction of plasma glucose at 2 hours (172.8+/-48.4 vs. 138.3+/-41.2 mg/dl; p < 0.001). The flow-mediated dilatation (FMD) 2 hours after the glucose-load was significantly reduced in comparison to fasting in the control group (6.21+/-2.69 vs. 7.98+/-2.24 %; p = 0.028), whereas after theadministration of repaglinide the FMD was not significantly different to fasting values (7.24+/-2.57 vs. 8.18+/-2.93 %; p = n.s.). Linear and logistic regression analysis revealed that only the change of glucose was significantly correlated to the change of FMD observed (p < 0.001). Regression analysis after grouping for treatment and time confirmed the strong negative association of the changes of plasma glucose and FMD and indicate that the effect of repaglinide observed is based on the reduction glycemia.
In subjects with IGT, the endothelial dysfunction observed after a glucose challenge is related to the extent of hyperglycemia. Reduction of hyperglycemia by repaglinide reduces endothelial dysfunction in a glucose dependent manner.
Anemia and diabetes are risk factors for short-term mortality following an acute myocardial infarction(AMI). Anemia is more prevalent in patients with diabetes. We performed a retrospective study to assess the impact of the combination of diabetes and anemia on post-myocardial infarction outcomes.
Data relating to all consecutive patients hospitalized with AMI was obtained from a population-based disease-specific registry. Patients were divided into 4 groups: diabetes and anemia (group A, n = 716), diabetes and no anemia (group B, n = 1894), no diabetes and anemia (group C, n = 869), and no diabetes and no anemia (group D, n = 3987). Mortality at 30 days and 31 days to 36 months were the main outcome measures.
30-day mortality was 32.3% in group A, 16.1% in group B, 21.5% in group C, 6.6% in group D (all p < 0.001). 31-day to 36-month mortality was 47.6% in group A, 20.8% in group B, 34.3% in group C, and 10.4% in group D (all p < 0.001). Diabetes and anemia remained independent risk factors for mortality with odds ratios of 1.61 (1.41–1.85, p < 0.001) and 1.59 (1.38–1.85, p < 0.001) respectively at 36 months. Cardiovascular death from 31-days to 36-months was 43.7% of deaths in group A, 54.1% in group B, 47.0% in group C, 50.8% group D (A vs B, p < 0.05).
Patients with both diabetes and anemia have a significantly higher mortality than those with either diabetes or anemia alone. Cardiovascular death remained the most likely cause of mortality in all groups.
Diabetes is a major risk factor for cardiovascular disease. In particular, type 1 diabetes compromises the cardiac function of individuals at a relatively early age due to the protracted course of abnormal glucose homeostasis. The functional abnormalities of diabetic myocardium have been attributed to the pathological changes of diabetic cardiomyopathy.
In this study, we used high field magnetic resonance imaging (MRI) to evaluate the left ventricular functional characteristics of streptozotocin treated diabetic Sprague-Dawley rats (8 weeks disease duration) in comparison with age/sex matched controls.
Our analyses of EKG gated cardiac MRI scans of the left ventricle showed a 28% decrease in the end-diastolic volume and 10% increase in the end-systolic volume of diabetic hearts compared to controls. Mean stroke volume and ejection fraction in diabetic rats were decreased (48% and 28%, respectively) compared to controls. Further, dV/dt changes were suggestive of phase sensitive differences in left ventricular kinetics across the cardiac cycle between diabetic and control rats.
Thus, the MRI analyses of diabetic left ventricle suggest impairment of diastolic and systolic hemodynamics in this rat model of diabetic cardiomyopathy. Our studies also show that in vivo MRI could be used in the evaluation of cardiac dysfunction in this rat model of type 1 diabetes.
Atherosclerosis is an inflammatory disease in which a perpetuated activation of NFkappaB via the RAGE (receptor for advanced glycation end products)-MAPK signalling pathway may play an important pathogenetic role. As recently S100 proteins have been identified as ligands of RAGE, we sought to determine the effects of the proinflammatory heterodimer of S100A8/S100A9 on the RAGE-NFkappaB mediated induction of proinflammatory gene expression.
Human umbilical vein endothelial cells (HUVEC) were preincubated for 72 h with AGE-albumin or unmodified albumin for control, whereas AGE-albumin induction resulted in an upregulation of RAGE. Following this preactivation, cells were stimulated for 48 h with heterodimeric human recombinant S100A8/S100A9.
Heterodimeric S100A8/S100A9 enhanced secretion of IL-6, ICAM-1, VCAM-1 and MCP1 in AGE-albumin pretreated HUVEC in a dose dependent manner. These effects could not be detected after stimulation with the homodimeric proteins S100A8, S100A9, S100A1 and S100B. The effects of heterodimeric S100A8/S100A9 were reduced by inhibition of the MAP-kinase pathways ERK1/2 and p38 by PD 98059 and SB 203580, respectively.
The heterodimeric S100A8/S100A9 might therefore play a hitherto unknown role in triggering atherosclerosis in diabetes and renal failure, pathophysiological entities associated with a high AGE burden. Thus, blocking heterodimeric S100A8/S100A9 might represent a novel therapeutic modality in treating atherosclerosis.
Monocytes play an important role in innate immunity and atherosclerosis. A disturbed secretion of cytokines in lipopolysaccharide (LPS) activated monocytes from type 1 diabetes (T1D) patients has been described and may contribute to the impaired inflammatory response in these individuals. In the present study the influence of LPS on five different proteins with a function in immunity and atherosclerosis was analyzed in monocytes from controls and T1D patients.
Monocytes were isolated from controls and T1D patients and the LPS-stimulated increase of IL-6, CXCL8, monocyte chemotactic protein 1 (CCL2, MCP-1) and superoxide dismutase (SOD 2), as well as the LPS-mediated decrease of apolipoprotein E (Apo E) in primary human monocytes from controls and T1D patients was determined.
CCL2 and IL-6 secretion in response to LPS was found significantly reduced in monocytes from T1D patients when compared to controls whereas basal CCL2 release was similar in control and T1D cells. In contrast, CXCL8 and apolipoprotein E secretion and SOD 2 expression upon LPS stimulation is similar from T1D and control monocytes.
These data indicate that LPS-mediated protein expression is only partly disturbed in monocytes from T1D patients. Reduced secretion of IL-6 and CCL2 in activated monocytes of these patients may contribute to an impaired inflammatory response and vascular disease.
The endothelium is a thin monocelular layer that covers all the inner surface of the blood vessels, separating the circulating blood from the tissues. It is not an inactive organ, quite the opposite. It works as a receptor-efector organ and responds to each physical or chemical stimulus with the release of the correct substance with which it may maintain vasomotor balance and vascular-tissue homeostasis. It has the property of producing, independently, both agonistic and antagonistic substances that help to keep homeostasis and its function is not only autocrine, but also paracrine and endocrine. In this way it modulates the vascular smooth muscle cells producing relaxation or contraction, and therefore vasodilatation or vasoconstriction. The endothelium regulating homeostasis by controlling the production of prothrombotic and antithrombotic components, and fibrynolitics and antifibrynolitics. Also intervenes in cell proliferation and migration, in leukocyte adhesion and activation and in immunological and inflammatory processes. Cardiovascular risk factors cause oxidative stress that alters the endothelial cells capacity and leads to the so called endothelial "dysfunction" reducing its capacity to maintain homeostasis and leads to the development of pathological inflammatory processes and vascular disease.
There are different techniques to evaluate the endothelium functional capacity, that depend on the amount of NO produced and the vasodilatation effect. The percentage of vasodilatation with respect to the basal value represents the endothelial functional capacity. Taking into account that shear stress is one of the most important stimulants for the synthesis and release of NO, the non-invasive technique most often used is the transient flow-modulate "endothelium-dependent" post-ischemic vasodilatation, performed on conductance arteries such as the brachial, radial or femoral arteries. This vasodilatation is compared with the vasodilatation produced by drugs that are NO donors, such as nitroglycerine, called "endothelium independent". The vasodilatation is quantified by measuring the arterial diameter with high resolution ultrasonography. Laser-Doppler techniques are now starting to be used that also consider tissue perfusion.
There is so much proof about endothelial dysfunction that it is reasonable to believe that there is diagnostic and prognostic value in its evaluation for the late outcome. There is no doubt that endothelial dysfunction contributes to the initiation and progression of atherosclerotic disease and could be considered an independent vascular risk factor. Although prolonged randomized clinical trials are needed for unequivocal evidence, the data already obtained allows the methods of evaluation of endothelial dysfunction to be considered useful in clinical practice and have overcome the experimental step, being non-invasive increases its value making it use full for follow-up of the progression of the disease and the effects of different treatments.
Hyperglycemia-induced changes in vascular wall structure contribute to the pathogenesis of diabetic microvascular and macrovascular complications. Matrix metalloproteinases (MMP), a family of proteolytic enzymes that degrade extracellular matrix (ECM) proteins, are essential for vascular remodeling. We have shown that endothelin-1 (ET-1) mediates increased MMP activity and associated vascular remodeling in Type 2 diabetes. However, the effect of Type 2 diabetes and/or ET-1 on the regulation of ECM and MMP gene expression in different vascular beds remains unknown.
Aorta and mesenteric artery samples were isolated from control, Type 2 diabetic Goto-Kakizaki (GK) rats and GK rats treated with ETA antagonist ABT-627. Gene expression profile of MMP-2, MMP-9, MT1-MMP, fibronectin, procollagen type 1, c-fos and c-jun, were determined by quantitative real-time (qRT) PCR. In addition, aortic gene expression profile was evaluated by an ECM & Adhesion Molecules pathway specific microarray approach.
Analysis of the qRT-PCR data demonstrated a significant increase in mRNA levels of MMPs and ECM proteins as compared to control animals after 6 weeks of mild diabetes. Futhermore, these changes were comparable in aorta and mesentery samples. In contrast, treatment with ETA antagonist prevented diabetes-induced changes in expression of MMPs and procollagen type 1 in mesenteric arteries but not in aorta. Microaarray analysis provided evidence that 27 extracellular matrix genes were differentially regulated in diabetes. Further qRT-PCR with selected 7 genes confirmed the microarray data.
These results suggest that the expression of both matrix scaffold protein and matrix degrading MMP genes are altered in macro and microvascular beds in Type 2 diabetes. ETA antagonism restores the changes in gene expression in the mesenteric bed but not in aorta suggesting that ET-1 differentially regulates microvascular gene expression in Type 2 diabetes.