Prospective study of autonomic neuropathy as a predictor of mortality in patients with diabetes

To investigate the relationships between serum concentrations of soluble adhesion molecules and hyperglycemia, insulin resistance, or other conventional risk factors in type 2 diabetes, we measured soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sE-selectin), insulin sensitivity, and conventional risk factors in 150 Japanese type 2 diabetic patients without apparent diabetic macroangiopathy. High serum concentrations of sVCAM-1 and sE-selectin were observed in patients with type 2 diabetes. Serum concentrations of soluble adhesion molecules were not significantly influenced by sex, hypertension, dyslipidemia, or microangiopathy. Spearman correlation showed that sVCAM-1 concentrations correlated significantly with fasting plasma glucose (FPG), fasting C-peptide, and insulin sensitivity [K index of the insulin tolerance test (K(ITT))] (rho=0.19,0.23, and -0.23, respectively). Soluble E-selectin concentrations correlated significantly with body mass index (BMI), FPG, fasting C-peptide, insulin sensitivity, and triglyceride (rho=0.33,0.42,0.26,-0.48, and 0.29, respectively). Multiple regression analysis showed that FPG, fasting C-peptide, and total cholesterol were independent factors that correlated with sVCAM-1 levels. BMI, FPG, and insulin sensitivity were independent factors that correlated with sE-selectin levels. Serum concentrations of sE-selectin significantly increased associated with clustering of conventional risk factors those obesity, hypertension, dyslipidemia, and current smoking (P<0.01). Thus, sVCAM-1 and sE-selectin levels are related to both hyperglycemia and insulin resistance. Soluble E-selectin levels may be related to obesity, hyperglycemia, and insulin resistance and may reflect the presence of a multiple risk factor clustering syndrome.     

Relationship between insulin resistance, soluble adhesion molecules, and mononuclear cell binding in healthy volunteers.

The relationship between insulin resistance, soluble adhesion molecules E-selectin (sE-selectin), intracellular adhesion molecule-1 (sICAM-1), and vascular adhesion molecule-1 (sVCAM-1), mononuclear cell binding to cultured endothelium, and lipoprotein concentrations were evaluated in 28 healthy, nondiabetic, and normotensive individuals. The mean (+/-SEM) lipid and lipoprotein concentrations were within the normal rage: cholesterol (199 +/- 18 mg/dL); triglyceride (128 +/- 12 mg/dL); low-density cholesterol (127 +/- 8 mg/dL; and high-density cholesterol (47 +/- 3 mg/dL). The results indicated that degree of insulin resistance was significantly correlated with concentrations of sE-selectin (r = 0.54, P < 0.005), sICAM-1 (r = 0.67, P < 0.001), and sVCAM-1 (r = 0.41, P < 0.05). Furthermore, the relationship between insulin resistance and both sE-selectin and sI-CAM-1 remained statistically significant when adjusted for differences in age, gender, body mass index, and all measures of lipoprotein concentrations. Finally, mononuclear cell binding correlated significantly with concentrations of sE-selectin (r = 0.54, P < 0.005) and sICAM-1 (r = 0.47, P < 0.01). These findings raise the possibility that previously described relationships between soluble adhesion molecules in patients with hypertension, type 2 diabetes, and dyslipidemia may be due to the presence of insulin resistance in these clinical syndromes and suggests that insulin resistance may predispose individuals to coronary heart disease by activation of cellular adhesion molecules.     

A double blind study of the effect of acipimox on serum lipids, blood glucose control and insulin action in non-obese patients with type 2 diabetes mellitus.

Hyperlipidaemia, in particular raised concentrations of serum triglycerides, together with raised plasma non-esterified fatty acid concentrations, is common in patients with Type 2 (non-insulin-dependent) diabetes mellitus and may be associated with insulin insensitivity. Thirty non-obese Type 2 diabetic patients (15 controlled with diet alone and 15 with diet plus oral sulphonylurea therapy) were therefore recruited to take part in a double-blind, randomized, crossover comparison of acipimox (250 mg three times daily for 3 months) and placebo. Serum lipids, blood glucose control, insulin sensitivity, and glucose tolerance were measured before and after each treatment period. There was a significant decrease in serum triglycerides (2.05 +/- 1.08 vs 2.91 +/- 1.75: p < 0.005), cholesterol (5.66 +/- 1.02 vs 6.26 +/- 1.17: p = 0.0005), and apoprotein B (1.32 +/- 0.23 vs 1.44 +/- 0.25: p < 0.05) while HDL cholesterol and apoprotein A-1 concentrations were unchanged. There was no change in blood glucose control measured by fasting glucose, insulin, and HBA, concentrations, but there was a significant improvement in insulin action assessed by glucose-insulin infusion. Although plasma non-esterified fatty acid concentrations were lower during the oral glucose tolerance test after acipimox, there was no difference in either the peak or 2-h plasma glucose concentrations and the total area under the glucose curve did not change. Acipimox was well tolerated and no patients withdrew from the study for drug-related symptoms. Thus, acipimox effectively lowers serum cholesterol and triglycerides in patients with Type 2 diabetes without adversely altering blood glucose control, and appears to improve insulin sensitivity.     

Circulating adhesion molecules levels in type 2 diabetes mellitus and hypertension

BACKGROUND: Risk factors for atherosclerosis such as hypertension, type 2 diabetes, obesity and dyslipidemia affect endothelial function and stimulate adhesion molecules expression. The aim of the study was to examine endothelial activation in type 2 diabetes and hypertension as indicated by adhesion molecule levels and further to investigate whether the coexistence of the above conditions has a different effect. METHODS: Serum levels of soluble E-selectin, ICAM-1 and VCAM-1 were measured in 17 hypertensive type 2 diabetic patients (DM-HY), 32 normotensive type 2 diabetic patients (DM), 11 hypertensive nondiabetic patients (HY) and 15 healthy subjects. RESULTS: In diabetic patients (either DM-HY or DM), soluble E-selectin levels were significantly increased compared to healthy subjects (p<0.001). In HY patients, both sE-selectin (66.44+/-71.59 vs. 29.42+/-15.56 ng/ml, p=0.033) and sVCAM-1 (1529+/-433.33 vs. 1027+/-243.56 ng/ml, p=0.03) levels were found significantly higher compared to healthy subjects (p<0.05). The coexistence of diabetes and hypertension (DM-HY) did not have an additive effect on circulating adhesion molecules levels compared with the levels observed in either diabetes or hypertension. Systolic and diastolic blood pressure (BP) were independent factors correlated respectively with sE-selectin and sVCAM-1 levels (R=0.454, p=0.034 and R=0.578, p=0.005) in nondiabetic subjects (hypertensive and normotensive). CONCLUSIONS: Type 2 diabetes mellitus and hypertension induce endothelial activation as indicated by elevated levels of soluble adhesion molecules. This effect is not different when comorbidity is present.     

Circulating E-selectin,vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 in men with coronary artery disease assessed by angiography and disturbances of carbohydrate metabolism

It is hypothesized that adhesion molecules could be an early predictor of coronary artery disease. Therefore we investigated the relationship between the concentrations of soluble forms of adhesion molecules and disturbances of glucose metabolism in 78 men referred for coronary angiography but with no previous history of diabetes. The group consisted of 78 men (mean age, 47.6 +/- 7.0 years; mean body mass index [BMI], 28.4 +/- 3.24 with the symptoms of angina pectoris and positive exercise test. All subjects were given a standard oral glucose tolerance test (OGTT) with glucose and insulin estimations. Fasting plasma concentrations of the soluble (s) forms of E-selectin, intercellular adhesion cell molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and HbA(1c) were also measured. According to the OGTT, 10.2% of the patients (n = 8) fulfilled the criteria for type 2 diabetes mellitus and 44.9% (n = 35) for impaired glucose tolerance (IGT). The highest concentrations of sE-selectin were observed in patients with type 2 diabetes mellitus and were significantly higher in comparison to the group with normal glucose tolerance and IGT. The concentration of sVCAM-1 increased with the progression of disturbances of glucose metabolism and remained the highest in type 2 diabetic patients. sICAM-1 concentration was not significantly different. sE-selectin concentration correlated significantly with fasting glucose (r = 0.23, P =.041), postload glucose (r = 0.39, P =.001), and postload insulin (r = 0.28, P =.023). sVCAM-1 was significantly related to the postload glucose concentration (r = 0.30, P =.009). A significant correlation between sICAM-1 concentration and postload insulin was also observed (r = 0.27, P =.025). This would suggest that hyperglycemia increases sE-selectin and sVCAM-1 in plasma, which reflects excessive formation of atherosclerotic plaques in patients with disturbances of glucose metabolism.     

A low-fat diet improves peripheral insulin sensitivity in patients with Type 1 diabetes.

AIMS: To compare the effects on insulin sensitivity, body composition and glycaemic control of the recommended standard weight-maintaining diabetes diet and an isocaloric low-fat diabetes diet during two, 3-month periods in patients with Type 1 diabetes. METHODS: Thirteen Type 1 patients were included, of whom 10 completed the cross-over study. Ten non-diabetic, matched control subjects were also examined. Body composition was estimated by dual-energy X-ray absorptiometry (DXA) whole-body scanning, diet intake was monitored by 7-day dietary record and insulin sensitivity was measured by the insulin clamp technique at baseline and after each of the diet intervention periods. RESULTS: On an isocaloric low-fat diet, Type 1 diabetic patients significantly reduced the proportion of fat in the total daily energy intake by 12.1% (or -3.6% of total energy) as compared with a conventional diabetes diet (P = 0.039). The daily protein and carbohydrate intake increased (+4.4% of total energy intake, P = 0.0049 and +2.5%, P = 0.34, respectively), while alcohol intake decreased (-3.2% of total energy intake, P = 0.02). There was a significant improvement in insulin sensitivity on the isocaloric, low-fat diet compared with the standard diabetes diet [7.06 +/- 2.16 mg/kg/min (mean +/- sd) vs. 5.52 +/- 2.35 mg/kg/min (P = 0.03)]. However, insulin sensitivity remained 33% lower than in the control subjects (P = 0.021). No significant changes occurred in body weight or body composition. Glycated haemoglobin rose during both diet intervention periods (P = 0.18), with no difference between the two diets. CONCLUSIONS: Change to an isocaloric, low-fat diet in Type 1 diabetic patients during a 3-month period resulted in significant improvement in insulin sensitivity without improvement in glycaemic control. However, insulin sensitivity remained 33% lower than in control subjects.     

The levels of soluble adhesion molecules in diabetic and nondiabetic patients with combined hyperlipoproteinemia and the effect of ciprofibrate therapy

Cell adhesion molecules are thought to play a role in atherosclerosis. Several clinical trials have shown that fibrate treatment leads to a reduction in coronary events, although the mechanisms are not fully understood. Soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble E-selectin plasma concentrations were measured in 10 obese dyslipidemic men (group A), in 10 obese dyslipidemic type 2 diabetic men without coronary artery disease (CAD) (group B), and in 10 dyslipidemic type 2 diabetic men with angiographically documented CAD (group C) before and after 12 weeks of treatment with ciprofibrate. Compared with nondiabetic dyslipidemic men, diabetic patients with CAD or without documented CAD had significantly increased levels of sVCAM-1 (512 +/-39 versus 750 +/-139 ng/mL; p<0.0001 and 566 +/-78 ng/mL; p<0.01, respectively) and sE-selectin (54.8 +/-6.9 versus 65.9 +/-8.8 ng/mL; p<0.001 and 62.6 +/-9.4 ng/mL; p=0.056, respectively). The levels of sICAM-1 were similar in all 3 groups. Multivariate analyses showed that the higher sCAM levels in patients occurred independently of lipoprotein levels. Waist circumference as a marker of abdominal adiposity was the only independent predictor of elevated concentrations of all 3 cell adhesion molecules in multivariate analyses. sE-selectin was associated with HbA1C levels (p<0.01) in diabetic men at baseline. After 12 weeks of ciprofibrate therapy, sVCAM-1 levels were reduced by 13.5 +/-2.1%, sICAM-1 levels by 11.8 +/-2.2%, and sE-selectin levels by 17.1 +/-3.5% (p<0.01 for all) with the greatest sE-selectin reduction in the diabetic subgroups (p<0.001). There was no correlation between the lowering of soluble adhesion molecules and the magnitude of lipid-lowering effect. An increased level of circulating adhesion molecules may be a mechanism by which dyslipidemia and/or diabetes mellitus promotes atherogenesis, and treatment with ciprofibrate may alter vascular cell activation.     

Beta-cell function evaluated by HOMA as a predictor of secondary sulphonylurea failure in Type 2 diabetes.

BACKGROUND AND AIMS: Secondary failure to oral hypoglycaemic agents, a common evolution of long-standing Type 2 diabetes, is usually assessed by non-standardized indices requiring fine clinical assessment, including hyperglycaemia resistant to maximum doses of sulphonylureas despite appropriate diet and follow-up. The goal of this study was to evaluate if HOMA, a modelized plasma insulin/glucose ratio allowing simple evaluation of residual insulin secretion and sensitivity, is a better predictor of the insulin requiring stage than clinical indices. MATERIALS AND METHODS: HOMA was measured in 84 Type 2 diabetic patients aged 58 +/- SD 6 years, with diabetes duration 11 +/- 4 years, hospitalized because of hyperglycaemia resistant to maximal doses of sulphonylureas (e.g. glibenclamide > or = 15 mg/day), with no apparent external reason for hyperglycaemia. Despite reinforced appropriate diet recommendations, 62 of these patients remained hyperglycaemic (insulin-requiring group). RESULTS: Age, duration of diabetes, body mass index (BMI) and HOMA value for insulin sensitivity (71 +/- 6% vs. 76 +/- 7%, normal values 59-161%) were comparable in the two groups. HbA(1c) was higher (10.0 +/- 0.2% vs. 8.3 +/- 0.3%, P < 0.001) and HOMA insulin secretion values lower (25 +/- 2% vs. 43 +/- 6%, normal values 70-150%, P < 0.01) in the insulin-requiring group. Of the following potential predictors: HbA(1c) > 8%, duration of diabetes > or = 10 years, HbA(1c) combined with diabetes duration, insulin sensitivity < or = 40%, insulin secretion < or = 20%, the latter showed the best positive predictivity (86% patients with low insulin secretion were insulin-requiring). CONCLUSIONS: (i) HOMA is a simple and good predictor of the insulin-requiring stage in Type 2 diabetes mellitus; (ii) this stage of diabetes is characterized by a further decline of insulin secretion rather than of insulin sensitivity. Diabet. Med. 18, 584-588 (2001)     

The effect of gliclazide on plasma insulin, intact and 32/33 split proinsulin in South Asian subjects with Type 2 diabetes mellitus.

AIMS: Previous studies have shown that in Caucasian subjects with Type 2 diabetes mellitus (DM), the sulphonylurea glibenclamide increased insulin secretion without causing an increase in 32/33 split proinsulin secretion. South Asian subjects with Type 2 DM are thought to be more insulin resistant and the effect of sulphonylureas may be different. We therefore investigated the effect of sulphonylurea therapy with gliclazide on beta-cell function in South Asian subjects with newly diagnosed Type 2 DM. METHODS: Glucose, insulin, and intact and 32/33 split proinsulin were measured at diagnostic oral glucose tolerance test (OGTT). After 8-12 weeks on a conventional diet, subjects with a fasting glucose > 6 mmol/l (n = 16) were commenced on gliclazide. RESULTS: At diagnosis, those requiring gliclazide were more hyperglycaemic but there was no difference in weight or fasting insulin concentration than in the diet group. Following diet, in the gliclazide group, weight fell (P < 0.04) with no change in fasting glucose concentration. Fasting intact proinsulin, insulin and 32/33 split proinsulin remained unchanged. After gliclazide therapy weight remained unchanged, but fasting glucose fell (P < 0.003). Fasting insulin and intact proinsulin remained unchanged but 32/33 split proinsulin fell (P < 0.05). Fasting insulin to glucose ratio significantly improved after gliclazide (P < 0.006). CONCLUSIONS: In South Asian subjects treated with gliclazide the reduction in fasting glucose concentrations appears to be due to an improvement in insulin sensitivity as well as in beta-cell function.     

Increased soluble E-selectin levels in type 2 diabetic patients with peripheral arterial disease.

AIM: Abnormal endothelial function is well known in patients with type 2 diabetes mellitus and thought to induce macroangiopathy. Increased levels of adhesion molecules have been found in type 2 diabetic patients and it has been suggested that they play an important role in the initiation of atherosclerosis. The aim of the present study was to clarify the relationship between objectively proven peripheral arterial disease (pAVD) and serum levels of soluble adhesion molecules in patients with type 2 diabetes mellitus. METHODS: Levels of soluble E-selectin, ICAM-1 and VCAM-1 were evaluated in 18 type 2 diabetic patients with pAVD assessed by Doppler ultrasound, in 19 type 2 diabetic patients and 22 non-diabetic subjects without pAVD. RESULTS: Soluble E-selectin levels were significantly increased in pAVD-diabetic patients compared to diabetics and non-diabetics without pAVD (78.7+/-29 vs 49.7+/-20.4 and 36+/-17 ng/ml respectively, p<0.001), while sICAM-1 and sVCAM-1 levels were comparable between the groups. No significant correlation was found between pAVD and adhesion molecule levels. Peripheral AVD was correlated with smoking (p=0.024), duration of diabetes (p=0.048) and microalbuminuria (p=0.041). Regression analysis revealed that only smoking (R=0.536, p=0.012) and glycosylated hemoglobin (R=0.435, p=0.036) were independent factors related to pAVD. Soluble ICAM-1 levels were significantly higher (p=0.041) in diabetic smokers with pAVD and sVCAM-1 (p=0.011) in patients with longer duration of diabetes. CONCLUSION: Type 2 diabetic patients with pAVD showed increased serum sE-selectin levels. No significant relationship was found between the presence or extent of pAVD and measured adhesion molecules. Our results suggest that sE-selectin reflects endothelial activation and is possibly involved in the atherogenesis process with the contribution of other factors that characterize the metabolic syndrome of diabetes.     

Effect of metformin treatment on multiple cardiovascular disease risk factors in patients with type 2 diabetes mellitus

In light of the conflicting results of the recent United Kingdom Prospective Study (UKPDS), where diabetic patients on metformin monotherapy had lower all-cause mortality and the addition of metformin in sulfonylurea-treated patients was associated with an increased risk of diabetes-related death, we sought to compare the effects on cardiovascular disease (CVD) risk factors of metformin monotherapy with metformin treatment when added to a sulfonylurea compound in patients with type 2 diabetes. Thirty-one volunteers with type 2 diabetes mellitus, 16 on dietary therapy and 15 on sulfonylurea monotherapy (SU), were treated with metformin for 12 weeks. Measurements were made of (1) fasting plasma glucose, hemoglobin A(1c) (HbA(1c)), lipid, remnant lipoprotein cholesterol (RLP-C) levels, and low-density lipoprotein (LDL) particle size; (2) daylong plasma glucose, insulin, free fatty acid (FFA), triglyceride (TG), and RLP-C concentrations; and (3) fasting levels of soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble E-selectin (sE-selectin). Fasting plasma glucose concentrations decreased to a similar degree after treatment with metformin in both the metformin monotherapy group (12.45 +/- 0.48 v 9.46 +/- 0.47 mmol/L, P <.001) and the combined SU and metformin therapy group (14.09 +/- 0.51 v 10.57 +/- 0.85 mmol/L, P =.001). Fasting plasma lipid concentrations and LDL particle size did not significantly change in either treatment group, whereas fasting RLP-C concentrations were significantly lower in the metformin monotherapy group (0.43 +/- 0.09 v 0.34 +/- 0.07 mmol/L, P =.02). Daylong concentrations of plasma glucose, FFA, TG, and RLP-C were lower to a similar degree in both treatment groups, whereas daylong plasma insulin concentrations were unchanged. Fasting plasma sVCAM-1 levels were significantly lower in both the metformin monotherapy group (484 +/- 19 v 446 +/- 18 ng/mL, P =.02) and the combined SU and metformin therapy group (496 +/- 29 v 456 +/- 31 ng/mL, P =.05), whereas fasting plasma sICAM-1 and sE-selectin levels were essentially unchanged. Administration of metformin, either as monotherapy or in combination with a sulfonylurea drug, improved glycemic control and led to a decrease in several CVD risk factors in patients with type 2 diabetes.     

Long-term effects of pioglitazone and metformin on insulin sensitivity in patients with Type 2 diabetes mellitus.

AIM: Despite their comparable glycaemic effects in patients with Type 2 diabetes mellitus (T2DM), pioglitazone and metformin may have different effects on insulin sensitivity because they have different mechanisms of action. We studied the changes in insulin sensitivity, as assessed by the Quantitative Insulin Sensitivity Check Index (QUICKI), in patients with T2DM who used metformin or pioglitazone as monotherapy or in combination therapy with sulphonylurea. METHODS: Data in this report are from two multicentre, randomized, double-blind, double-dummy studies conducted in Europe (monotherapy) or in Europe and Canada (combination therapy study). Patients were randomized to 52 weeks of treatment consisting of a 12-week forced titration period and a 40-week maintenance period. HbA(1c), fasting plasma glucose (FPG) and fasting serum insulin (FSI) were quantified from a single blood sample at weeks 0, 8, 16, 24, 32, 42 and 52. Insulin sensitivity was assessed with QUICKI, which is calculated from FSI and fasting blood glucose (FBG) concentrations using the formula 1/(log(10) FSI + log(10) FBG). Time course effects of the treatments were compared by repeated measures analysis of covariance. RESULTS: As monotherapy, pioglitazone and metformin increased QUICKI compared with baseline (baseline vs. end point [mean +/- sem]; pioglitazone [0.303 +/- 0.001 vs. 0.321 +/- 0.001; P < 0.001] and metformin [0.304 +/- 0.001 vs. 0.315 +/- 0.001; P < 0.001]). Pioglitazone increased insulin sensitivity more than metformin from week 4 through week 52. There were significant increases in QUICKI from baseline in both combination therapy groups (baseline vs. end point; pioglitazone + sulphonylurea [0.305 +/- 0.001 vs. 0.319 +/- 0.001; P < 0.001] and metformin + sulphonylurea [0.306 +/- 0.001 vs. 0.317 +/- 0.001; P < 0.001]). Overall, pioglitazone + sulphonylurea significantly increased insulin sensitivity more than metformin + sulphonylurea. CONCLUSION: Pioglitazone differed from metformin in its effects on insulin sensitivity despite both drugs having comparable glycaemic effects.     

The lipoprotein profile differs during insulin treatment alone and combination therapy with insulin and sulphonylureas in patients with Type 2 diabetes mellitus.

AIMS: To study whether changes in endogenous insulin secretion at the same glycaemic control affect the plasma concentrations of lipoproteins in patients with Type 2 diabetes mellitus. METHODS: Fifteen patients, age 59+/-2 years (mean +/- SEM), body weight 86.3+/-3.0kg, body mass index 29.6+/-0.9 kg/m2 were treated with sulphonylurea and insulin in combination or with insulin alone in a randomized, double-blind, crossover study. All patients were treated with a multiple daily injection regimen with the addition of glibenclamide 10.5 mg daily or placebo tablets. RESULTS: During combination therapy, the dose of insulin was 25% less (P < 0.002) and there was a 29% increase in plasma C-peptide concentration (P = 0.01). Plasma levels of free insulin were not changed. Plasma levels of sex hormone-binding globulin (SHBG) and insulin-like growth factor-binding protein (IGFBP)-1 were lowered. There were no differences in the 24-h blood glucose profiles or HbA1c (6.0+/-0.2 vs. 6.3+/-0.2%; P = 0.16). Body weight was similar. There was a significant decrease in plasma LDL cholesterol (3.04+/-0.24 vs. 3.41+/-0.21 mmol/l; P = 0.04), apolipoprotein A1 and of lipoprotein(a) but an increase in VLDL-triglycerides (1.36+/-0.31 vs. 0.96+/-0.16 mmol/l; P = 0.02) during combination therapy. The ratio between LDL cholesterol and apolipoprotein B concentrations was significantly lower during combination therapy (P < 0.01). CONCLUSIONS: Combination therapy with insulin and sulphonylureas increases portal insulin supply and thereby alters liver lipoprotein metabolism when compared with insulin therapy alone.     

Vascular endothelium and inflammatory process, in patients with combined Type 2 diabetes mellitus and coronary atherosclerosis: the effects of vitamin C.

AIMS: Type 2 diabetes mellitus (DM) and coronary artery disease (CAD) are both associated with endothelial dysfunction and elevated oxidative and inflammatory state. We examined the effect of vitamin C on endothelial function and levels of soluble vascular cell adhesion molecule (sVCAM-1), interleukin-6 (IL-6) and tumour necrosis factor (TNF-alpha), in DM patients with or without CAD and in non-diabetic subjects. METHODS: Thirty-seven patients with DM + CAD, 17 patients with DM without CAD and 21 non-diabetic subjects were divided into groups receiving vitamin C 2 g/day or no anti-oxidant for 4 weeks. Forearm blood flow was determined using venous occlusion gauge-strain plethysmography. Forearm vasodilatory response to reactive hyperemia was considered as index of endothelium-dependent dilation. RESULTS: Baseline levels of IL-6 and TNF-alpha were significantly higher in patients with DM + CAD compared with patients with DM (P < 0.01) or non-diabetic subjects (P < 0.01). IL-6 and TNF-alpha levels were also higher in DM compared with non-diabetic subjects (P < 0.05). sVCAM-1 levels were lower in non-diabetic controls compared with DM + CAD (P < 0.05) or DM (P < 0.05). Reactive hyperaemia was higher in non-diabetic controls compared with DM + CAD (P < 0.001) or DM (P < 0.001). Vitamin C significantly increased reactive hyperaemia only in the DM + CAD group, while it had no effect on serum levels of sVCAM-1, TNF-alpha and IL-6 in any of the groups. CONCLUSIONS: Type 2 diabetes mellitus is associated with impaired endothelial function and increased levels of TNF-alpha, IL-6 and sVCAM-1, especially in patients with DM and CAD. Vitamin C significantly increased forearm vasodilatory response to reactive hyperaemia only in patients with combined DM and CAD.     

High serum concentrations of soluble E-selectin in patients with impaired glucose tolerance with hyperinsulinemia

High serum concentrations of soluble adhesion molecules are present in diabetics, but whether similar levels are present in patients with impaired glucose tolerance (IGT) is unclear. We measured serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), and sE-selectin in 128 nondiabetic Japanese subjects. The concentrations of sICAM-1, sVCAM-1, and sE-selectin in IGT patients (n=47) were not different from those in subjects with normal glucose tolerance (NGT; n=81). IGT patients were subdivided into two groups by the results of 75 g OGTT, those with low- (hypoinsulinemia; n=23) or high-insulin (hyperinsulinemia; n=24). The levels of sICAM-1 and sVCAM-1 were not different among NGT and IGT with high-insulin or with low-insulin. However, sE-selectin concentrations were significantly higher in IGT patients with high-insulin than in NGT and IGT with low-insulin (61.1+/-3.4, 47.1+/-1.8 and 43.7+/-3.9 ng/ml, respectively, P<0.001). Adjustment for age and gender did not influence the results. Serum sE-selectin concentrations correlated significantly with the area under the curve of insulin (AUC(insulin)), AUC(glucose), diastolic blood pressure, and triglyceride levels (r=0.35, 0.26, 0.18 and 0.21, respectively), and negatively with HDL-cholesterol levels (r=-0.20). Multiple regression analysis showed that AUC(insulin) was the only independent factor that correlated with sE-selectin levels (P<0.001). Our results indicate that hyperinsulinemia/insulin resistance may be responsible for the elevation of sE-selectin levels.     

Effects of insulin dependence on inflammatory process, thrombotic mechanisms and endothelial function, in patients with type 2 diabetes mellitus and coronary atherosclerosis

BACKGROUND: Type 2 diabetes mellitus (T2DM) is characterized by endothelial dysfunction, increased thrombogenicity and abnormal inflammatory response. HYPOTHESIS: We hypothesizsed that insulin dependence/exogenous insulin administration may affect thrombotic/inflammatory status and endothelial function in patients with T2DM and coronary artery disease (CAD). METHODS: Fifty-five patients with T2DM + CAD (26 insulin-treated (INS) and 29 under oral biguanide + sulphonylurea (TABL)) were recruited. Endothelial function was assessed by gauge-strain plethysmography, and serum levels of inflammatory and thrombotic markers were determined by enzyme linked immunosorbent assay. RESULTS: There was no significant difference in endothelium-dependent dilation (EDD) between the study groups, while EDD was correlated with fasting glucose levels in both INS (r = - 0.776, p = 0.0001) and TABL (r = - 0.702, p = 0.0001). Patients in INS group had higher levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein (MCP-1) and vascular cell adhesion molecule (sVCAM-1), compared to TABL. However, TNF-alpha was negatively correlated with protein C (PrtC) only in INS (r = - 0.726, p = 0.01) but not in TABL group (r = - 0.066, p = 0.738). Similarly, sVCAM-1 was correlated with PrtC only among INS patients (r = - 0.451, p = 0.046) but not in TABL (r = 0.069, p = 0.727). In multivariate analysis, insulin dependence was a predictor of IL-6, TNF-alpha, MCP-1 and sVCAM-1 levels independently from the patients' demographic characteristics, the angiographic extend of CAD or the duration of diabetes. CONCLUSIONS: Insulin treatment in patients with type 2 diabetes mellitus affects the expression of inflammatory cytokines and subsequently modifies the thrombotic mechanisms in patients with coronary atherosclerosis, independently from the duration of diabetes and the extend of coronary artery disease.     

Neutrophil surface expression of CD11b and CD62L in diabetic microangiopathy

The aims of the study are (1) assessment of cell surface expression of adhesion molecules CD11b and CD62L on peripheral blood neutrophils in patients with type 2 diabetes and microangiopathy; (2) analysis of serum levels of soluble adhesion molecules: E-selectin (sE-selectin), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1) and von Willebrand factor (vWF) and; (3) evaluation of systemic inflammatory markers like interleukin-6 (IL-6), soluble interleukin-6 receptor (IL-6Rs), high sensitivity C-reactive protein (hsCRP) and fibrinogen. Thirty patients with type 2 diabetes and microangiopathy were enrolled in the study. The study group was compared to 22 patients with type 2 diabetes without microangiopathic compliations. The control group included 20 healthy volunteers. Flow cytometry was used to analyse surface expression of adhesion molecules. Both inflammatory markers and soluble adhesion molecules were determined by immunoenzymatic assay. A significant increase in neutrophil surface CD11b expression (P < 0.01) as well as decrease in surface CD62L expression (P < 0.01) were observed in the group with diabetic microangiopathy in comparison with diabetic group without microangiopathic complications and healthy controls. Moreover, significantly higher concentrations of sICAM-1 (P < 0.05), sVCAM-1 (P < 0.05), sE-selectin (P < 0.05), vWF (P < 0.01), hsCRP (P < 0.01), IL-6 (P < 0.01) and fibrinogen (P < 0.001) were also found in patients with microangiopathy in comparison with the control group. IL-6Rs concentrations did not significantly vary between groups. We concluded (1) diabetic microangiopathy is accompanied by increase in CD11b expression and decrease in CD62L expression on peripheral blood neutrophils; (2) in diabetic microangiopathy rise in CD11b expression indicates neutrophil activation and intensified adhesion; (3) the development of diabetic microangiopathy is accompanied by an increase in soluble adhesion molecules and inflammatory markers concentrations in the blood.     

Plasma concentrations of VCAM-1 and ICAM-1 are elevated in patients with Type 1 diabetes mellitus with microalbuminuria and overt nephropathy.

AIMS: Elevated urinary albumin excretion is associated with macrovascular atherosclerotic complications in Type 1 diabetes mellitus. Adhesion molecules mediate leucocyte adhesion to the endothelium early in the atherosclerotic process. The present study tests the hypothesis that microalbuminuria and diabetic nephropathy are associated with elevated plasma concentrations of soluble vascular adhesion molecule (sVCAM)-1, soluble intercellular adhesion molecule (sICAM)-1, and soluble E-selectin (sE-selectin) aiming to illustrate factors of potential pathogenetic relevance for the excess cardiovascular disease in diabetic patients with renal complications. METHODS: Soluble adhesion molecule concentrations were measured by enzyme-linked immunosorbent assays (ELISA) in healthy controls (n = 16) and in 59 Type 1 diabetic patients: group 1-patients with normoalbuminuria (n = 16); group 2-patients with microalbuminuria (n = 15); group 3-patients with macroalbuminuria and normal serum creatinine (n = 15), group 4-patients with macroalbuminuria and moderately elevated serum creatinine (n = 13). RESULTS: Plasma concentrations of sVCAM-1 and sICAM-1 were similar in healthy controls and normoalbuminuric Type 1 diabetic patients, but the concentrations were increased by the presence of microalbuminuria and overt nephropathy (P < 0.001 and P < 0.0001, ANOVA). Concentrations of sE-selectin did not differ between diabetic patients and controls. CONCLUSIONS: Plasma concentration of sICAM-1 is elevated in Type 1 diabetic patients with microalbuminuria and the concentrations of sICAM-1 as well as sVCAM-1 are elevated in patients with macroalbuminuria and normal s-creatinine. The elevated plasma concentrations of these soluble adhesion molecule concentrations in patients with renal complication can be of pathogenetic importance for the development of atherosclerosis and plasma soluble adhesion molecule concentrations may provide additional information on cardiovascular risk.     

Circulating adhesion molecules in sera of asthmatic children

Infiltration of cells into the lung in asthma is regulated by several expressions of cell adhesion molecules (CAMs) on cells present in the airways, and may play a role in the pathogenesis of bronchial asthma. We sought to evaluate the role of serum concentrations of the soluble forms of intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), and E-selectin (sE-selectin) in the control of disease activity in acute asthma. Circulating levels of sICAM-1, sVCAM-1, and sE-selectin in sera from 15 normal control subjects and from 20 allergic asthmatic children with acute exacerbations who had returned to stable condition were determined by using commercially available enzyme-linked immunosorbent assay kits. The mean concentration of serum sICAM-1 levels was significantly higher during an acute exacerbation of asthmatic children than in those with stable asthma (19.41 +/- 10.65 ng/mL vs. 13.46 +/- 5.44 ng/mL; P < 0.001) or in control subjects (9.83 +/- 2.02 ng/mL; P < 0.001). For sVCAM-1 and sE-selectin, the mean serum concentration of sVCAM-1 was slightly higher in children during an acute exacerbation asthma than when stable. However, the differences did not reach statistical significance. The mean serum concentrations of sVCAM-1 and sE-selectin in acute asthma or stable asthma were significantly higher than in control subjects. This study provides further evidence that serum concentrations of sICAM-1, sVCAM-1, and sE-selectin are increased in acute asthma. These findings further confirm that leukocyte endothelial adhesion plays a role in inflammatory airway disease.     

The effect of cigarette smoking on soluble adhesion molecules in middle-aged patients with Type 2 diabetes mellitus.

AIMS: To investigate the effect of smoking on soluble adhesion molecules in middle-aged diabetic patients. METHODS: One hundred out-patients with Type 2 diabetes and 100 age- and sex-matched non-diabetic subjects without clinical macrovascular disease were selected. Soluble serum levels of adhesion molecules were analysed using enzyme immunoassay. Carotid atherosclerosis was assessed using an ultrasound system. RESULTS: When compared with non-diabetic subjects, soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), and sE-selectin were found at significantly high levels in diabetic patients and significantly higher levels of sICAM-1, sE-selectin, and sP-selectin were observed in current smokers than never-smokers among diabetic or non-diabetic subjects, respectively. The combined, but not enhanced, effects of diabetes mellitus and smoking were observed in sICAM-1 and sE-selectin levels. Additionally, levels of sICAM-1 (P < 0.05) and sE-selectin (P < 0.01), but not sP-selectin, were high in ex-smokers when compared with never-smokers among diabetic patients. Diabetic smokers were also found to have marked carotid atherosclerosis, which was related to increased levels of sICAM-1. CONCLUSIONS: Our present study shows that levels of adhesion molecules were higher in diabetic smokers than diabetic non-smokers or non-diabetic smokers, and that cessation after chronic smoking did not restore the levels of sICAM-1 and sE-selectin, though sP-selectin levels were restored. These data suggest a possible mechanism for accelerated atherosclerosis induced by smoking in patients with diabetes.