Serum concentrations of soluble vascular cell adhesion molecule-1 and E-selectin are elevated in insulin-resistant patients with type 2 diabetes

Postural variation of pulmonary diffusing capacity as a marker of lung microangiopathy in Indian patients with type 2 diabetes mellitus

INTRODUCTION

Diabetes mellitus (DM) is characterized by the presence of chronic hyperglycemia and formation of advanced glycation end products (AGEs). Interaction between AGE and its receptor leads to endothelial damage and microangiopathy. This study was undertaken to investigate the possibility of using a postural variation of diffusing capacity as an early marker of lung microangiopathy and its correlation with the level of adhesion molecules, HbA1c, duration of diabetes, and insulin resistance in type 2 DM (T2DM) patients with and without microangiopathy.

MATERIALS AND METHODS

Forty patients having T2DM without any microangiopathy (n = 20) as well as with microangiopathy (n = 20), and 22 age and sex matched healthy controls were enrolled in this cross-sectional study. Measurement of lung volumes and capacities were done. DLco was measured in sitting and supine position. Levels of vascular cell adhesion molecule-1 (VCAM-1), E-selectin, fasting glucose, and insulin were estimated in plasma of the patients and compared with controls.

RESULTS

Restrictive type of ventilatory change was observed in DM patients. Diffusing capacity (% predicted) in the supine position (P < 0.0001), postural change in DLco (P < 0.0001), and coefficient of diffusion were significantly less in DM patients as compared to controls. Plasma levels of VCAM-1 were significantly higher in DM patients without microangiopathy and negatively correlated (r = -0.4054, P = 0.0094) with Δ DLco in all diabetic subjects. All patients had significantly higher insulin resistance.

CONCLUSION

Lack of postural increase in diffusing capacity in type 2 diabetic patients along with increased VCAM-1 levels could reflect the presence of an early microangiopathy of the small pulmonary vessels.

Soluble adhesion molecule E-selectin predicts cardiovascular events in Japanese patients with type 2 diabetes mellitus

Soluble adhesion molecule E-selectin (sE-selectin) is a marker of endothelial activation. To investigate whether high serum concentrations of sE-selectin could predict cardiovascular events, we followed 392 Japanese patients with type 2 diabetes mellitus who had no history of cardiovascular disease for a mean period of 6 years. The cardiovascular end points were defined as fatal and nonfatal myocardial infarction, angina pectoris, stroke, and sudden death. During the follow-up period, 51 patients reached end point. Patients who reached end point were significantly older and had longer duration of diabetes, higher systolic blood pressure, higher hemoglobin A1c, higher plasma glucose, higher sE-selectin, and lower high-density lipoprotein cholesterol compared with those free of such events. The mean serum concentration of sE-selectin was higher in patients who reached end point (81.1 +/- 32.2 ng/mL) than event-free patients (66.7 +/- 33.7 ng/mL, mean +/- SD; P < .01). Multiple logistic regression analysis identified age, systolic blood pressure, total cholesterol, sE-selectin, and low high-density lipoprotein cholesterol as independent factors related to cardiovascular events. The odds ratio for cardiovascular events for 1-SD increase in sE-selectin concentration was 1.45 (95% confidence interval, 1.22-1.71). Kaplan-Meier analysis demonstrated a significantly higher cardiovascular event rate in the highest tertile of sE-selectin compared with the lowest or middle tertile of sE-selectin (P < .01). The results suggest that high serum concentrations of sE-selectin can predict cardiovascular events in Japanese patients with type 2 diabetes mellitus.

Diabetes is a proinflammatory state: a translational perspective

The diabetic state confers an increased propensity to accelerated atherogenesis. Inflammation is pivotal in atherosclerosis; in addition to the established risk factors, inflammation appears to play a pivotal role in diabetes and its complications. Evidence for increased inflammation includes: increased levels of plasma C-reactive protein, the prototypic marker of inflammation; increased levels of plasminogen-activator inhibitor; increased monocyte superoxide and proinflammatory cytokine release (IL-1, IL-6 and TNF-alpha); increased monocyte adhesion to endothelium; increased NF-kappaB activity; and increased Toll-like receptor 2 and 4 expression and activity in diabetes. Thus, it appears that both Type 1 and Type 2 diabetes are proinflammatory states and that these could contribute to increased diabetic vasculopathies.

Coexistence of insulin resistance and inflammation effectively predicts cardiac disease but not stroke in Japanese patients with type 2 diabetes mellitus

It is well known that insulin resistance (IR) and inflammation (IF) are associated with macroangiopathy. However, whether IR and IF are related to cardiac disease (myocardial infarction, angina pectoris, and heart failure), stroke or both remains elusive. The present hospital-based prospective study was designed to investigate this issue. The study subjects were 300 Japanese patients with type 2 diabetes mellitus and negative history of cardiac disease and stroke. IR (K index of insulin tolerance test; K(ITT)) and IF (high-sensitivity C-reactive protein [hs-CRP]) were measured in each patient at baseline. Patients were followed-up for a mean period of 5.5 years. The time of first evidenced cardiac disease or stroke was monitored. During the follow-up, 35 patients developed cardiac disease and 26 patients developed stroke. Age, smoking, K(ITT), and hs-CRP were independently related to cardiac disease, while age, systolic blood pressure, low HDL, and anti-platelet drug use were independently related to stroke. When patients were subdivided into IR(-) and IR(+), and IF(-) and IF(+), Kaplan-Meier survival analysis showed that the rate of cardiac disease, but not of stroke, was significantly higher in IR(+)IF(+) than IR(-)IF(-) patients (p < 0.01). In conclusion, coexistence of IR and IF effectively predicted cardiac disease but not stroke in Japanese patients with type 2 diabetes mellitus.

Markers of endothelial dysfunction in hyperglycaemic Asian Indian subjects

OBJECTIVE

The aims of this study were the following: (1). to determine the levels of endothelin-1(ET1), soluble adhesion molecules like intracellular adhesion molecule-1 (sICAM-1), and vascular cell adhesion molecule-1 (sVCAM-1) in different stages of glucose intolerance and to identify a suitable marker of endothelial dysfunction and (2). to determine the possible association of these biochemical parameters with diabetic complications and with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

In this cross-sectional study, plasma ET1, sICAM-1, and sVCAM-1 were measured by enzyme-linked immunosorbent assay (ELISA) in 20 nondiabetic subjects, in 15 subjects with IGT, in 21 Type 2 diabetic subjects without any complication, and in 21 Type 2 diabetic patients with nephropathy and retinopathy.

RESULTS

Median ET1 levels were significantly elevated (P=.004) in IGT subjects (0.31 fmol/ml) when compared with the nondiabetic subjects (0.11 fmol/ml). Subjects with nephropathy (0.50 fmol/ml) had significantly higher (P=.002) ET1 values when compared with those without complications (0.40 fmol/ml). The levels of sICAM-1 and sVCAM-1 did not show any significant difference among the groups. ET1 showed correlation with age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose (FPG), 2 h post glucose (2hPG), waist-to-hip ratio (WHR), total white blood corpuscles count, glycosylated haemoglobin (HbA1c), triglycerides (TG), very-low-density lipoprotein cholesterol (VLDLc), and hypertension (HTN). In the multiple linear regression analysis, plasma ET1 was significantly associated with the presence of Type 2 diabetes either with or without complications (P<.0001 and P=.0098, respectively), WHR (P=.0063), and sVCAM-1 (P=.0051). The total variance explained by the above-mentioned parameters was 55%.

CONCLUSION

Elevated levels of ET1 were present in subjects with IGT and in Type 2 diabetic subjects. Such associations with sICAM-1 or sVCAM-1 in these subjects were not seen. ET1 could be an early marker of endothelial dysfunction, which appeared to occur even in the subclinical stages of hyperglycaemia.

Inflammation and insulin resistance are independently related to all-cause of death and cardiovascular events in Japanese patients with type 2 diabetes mellitus

Insulin resistance (IR)/hyperinsulinemia and low-grade inflammation (high-sensitivity C-reactive protein [hs-CRP]) can predict cardiovascular disease. However, because IR and inflammation (IF) have not been evaluated simultaneously, it is not known whether IR and IF are independently related to cardiovascular disease. Furthermore, the combined effect of IR and IF on the prediction of cardiovascular disease is presently unknown. Thus, we measured insulin sensitivity (K index of the insulin tolerance test; KITT) and hs-CRP in 350 Japanese patients with type 2 diabetes, and followed them for 1-7 years (mean, 4.5 years). During the follow-up, 33 patients died and 53 patients developed non-fatal coronary artery disease or stroke (endpoint). Age, systolic blood pressure, current smoking, past history of cardiovascular disease, KITT, and hs-CRP independently and significantly correlated with endpoint. One-S.D. difference was associated with a significant increase of relative risk in KITT (1.45; 95% CI 1.09-1.91) and hs-CRP (1.30; 1.04-1.67). When patients were subdivided to tertile, the relative risk in the highest tertile of KITT was 1.76 (95% CI 1.01-3.11) and hs-CRP was 2.00 (1.03-3.85) compared with the patients with lowest tertile. The relative risk in the highest tertile of both KITT and hs-CRP was 5.32 (1.18-24.0) compared with the lowest tertile of both values. In conclusion, low-grade IF and IR are independently related to all-cause of death and cardiovascular disease in Japanese patients with type 2 diabetes. Coexistence of low-grade IF and IR amplify this effect.

E-selectin-inducing activity in plasma from type 2 diabetic patients with maculopathy

Diabetic maculopathy (DMa) is a leading cause of visual loss in the western world. We examined whether plasma from type 2 diabetic patients with DMa contains factor(s) capable of inducing expression of the adhesion molecules E-selectin and VCAM-1 or cellular proliferation in cultured endothelial cells. Four gender-, age-, and duration (diabetes groups)-matched groups of 20 subjects each participated: 1) subjects with normal glucose tolerance (NGT), 2) subjects with impaired glucose tolerance (IGT), 3) type 2 diabetic patients without retinopathy, and 4) type 2 diabetic patients with DMa. Fasting plasma was added to in vitro-grown human umbilical vein endothelial cells for 6 h, after which E-selectin and VCAM-1 expression was measured. Proliferation was evaluated by thymidine incorporation. The individuals were characterized by measurement of 24-h ambulatory blood pressure, urinary albumin excretion rate, Hb A(1c), and blood lipids. Plasma from type 2 diabetic patients with DMa induced a significantly higher expression of E-selectin in endothelial cells than did plasma from subjects with NGT (259 +/- 23 x 10(3) vs. 198 +/- 19 x 10(3); arbitrary absorbance units; P < 0.05). There were no significant differences in plasma stimulatory effects on VCAM-1 expression or on thymidine incorporation between groups. These findings suggest that plasma from type 2 diabetic patients with DMa contains factor(s) capable of inducing the expression of E-selectin in endothelial cells. Enhanced expression of E-selectin may contribute to the development of DMa in type 2 diabetes.