Cardiovascular risk assessment in type 2 diabetes mellitus.
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Cardiovascular Diseases↗
Biomedical subjects
Edward S Horton
Publications and source records attributed to Edward S Horton.
Physical activity in individuals at risk for diabetes: Diabetes Prevention Program.
PURPOSE AND METHODS: Leisure physical activity was assessed using questionnaires with different time frames in the Diabetes Prevention Program (DPP) cohort of 3234 overweight individuals aged > 25 yr with impaired glucose tolerance (IGT) from 27 centers across the United States. The three questionnaires were the Modifiable Activity Questionnaire (MAQ; past year), the Low-Level Physical Activity Recall (LOPAR; past 7 d), and the Third National Health and Nutrition Examination Survey (NHANES III; past month). This provided the opportunity to examine the relationship between the three activity measures and to compare activity levels of the DPP sample with that of a national sample with IGT. RESULTS: Leisure activity determined by the three questionnaires significantly correlated with each other, although the correlations between MAQ and NHANES III were stronger (men: rho = 0.52; women: rho = 0.49; P < 0.01) than between LOPAR and either measure (men: rho = 0.20 for MAQ, 0.24 for NHANES; women: rho = 0.10 for MAQ, 0.13 for NHANES). In the DPP, measures of obesity and glucose tolerance were significantly correlated with activity levels determined by MAQ and NHANES, but not LOPAR. Activity levels in DPP participants determined by the NHANES III questionnaire were generally higher than those reported by individuals meeting DPP eligibility criteria who were part of the NHANES cohort for similar age, body mass index, and race or ethnicity. CONCLUSION: If the DPP participants were more active than a national sample of individuals with IGT, this would have implications for translation when using the DPP lifestyle intervention in less active or less motivated populations. Finally, the weak relationship between activity levels obtained with MAQ and LOPAR may result from the fact that they encompass different time frames and different components of leisure activity.
Adult↗
Diabetes enhances vulnerability to particulate air pollution-associated impairment in vascular reactivity and endothelial function.
BACKGROUND: Epidemiological studies suggest that people with diabetes are vulnerable to cardiovascular health effects associated with exposure to particle air pollution. Endothelial and vascular function is impaired in diabetes and may be related to increased cardiovascular risk. We examined whether endothelium-dependent and -independent vascular reactivity was associated with particle exposure in individuals with and without diabetes. METHODS AND RESULTS: Study subjects were 270 greater-Boston residents. We measured 24-hour average ambient levels of air pollution (fine particles [PM2.5], particle number, black carbon, and sulfates [SO4(2-)]) approximately 500 m from the patient examination site. Pollutant concentrations were evaluated for associations with vascular reactivity. Linear regressions were fit to the percent change in brachial artery diameter (flow mediated and nitroglycerin mediated), with the particulate pollutant index, apparent temperature, season, age, race, sex, smoking history, and body mass index as predictors. Models were fit to all subjects and then stratified by diagnosed diabetes versus at risk for diabetes. Six-day moving averages of all 4 particle metrics were associated with decreased vascular reactivity among patients with diabetes but not those at risk. Interquartile range increases in SO4(2-) were associated with decreased flow-mediated (-10.7%; 95% CI, -17.3 to -3.5) and nitroglycerin-mediated (-5.4%; 95% CI, -10.5 to -0.1) vascular reactivity among those with diabetes. Black carbon increases were associated with decreased flow-mediated vascular reactivity (-12.6%; 95% CI, -21.7 to -2.4), and PM2.5 was associated with nitroglycerin-mediated reactivity (-7.6%; 95% CI, -12.8 to -2.1). Effects were stronger in type II than type I diabetes. CONCLUSIONS: Diabetes confers vulnerability to particles associated with coal-burning power plants and traffic.
Adult↗
Troglitazone-induced changes in adiponectin do not affect endothelial function in diabetes.
OBJECTIVE: Adiponectin has been proposed to be related to endothelial function. We have examined the relationship between the increase in adiponectin levels that is associated with troglitazone treatment and endothelium-dependent vasodilation in type 2 diabetic patients. RESEARCH METHODS AND PROCEDURES: Seventy-two patients participated in this randomized, placebo-controlled, double-blinded study. High-resolution ultrasound images were used to measure the flow-mediated dilation (endothelium-dependent) and nitroglycerin-induced dilation (endothelium-independent) of the brachial artery. Laser Doppler perfusion imaging was employed to measure the vascular reactivity in the forearm skin. RESULTS: Troglitazone treatment resulted in an average 75% increase in the adiponectin levels, but no changes were observed in the endothelium-dependent vasodilation, any other measurement of vascular reactivity, or any other markers of endothelial activation. Also, no changes were observed in the expression of the receptor for advanced glycation end-products in skin biopsies taken from the forearm. Significant correlations were observed during troglitazone treatment between the changes in the adiponectin levels and the changes in fasting plasma glucose (r = -0.29, p < 0.05), hemoglobin A(1c) (r = -0.30, p < 0.05), total cholesterol (r = 0.25, p < 0.05), and low-density lipoprotein-cholesterol (r = 0.34, p < 0.01). DISCUSSION: The increase in adiponectin levels after troglitazone treatment is not associated with an improvement in the endothelium-dependent vasodilation, indicating that adiponectin is not a major determinant of endothelial function. In addition, receptor for advanced glycation end-products expression in the skin microcirculation is not affected by troglitazone treatment.
Adiponectin↗
The effect of vitamin E on endothelial function of micro- and macrocirculation and left ventricular function in type 1 and type 2 diabetic patients.
We examined the effects of high-dosage vitamin E treatment over a 12-month period on the vascular reactivity of micro- and macrocirculation and left ventricular function in diabetic patients. Subjects (n = 89) were randomized to vitamin E (1,800 IU daily) or placebo and were followed for 12 months. High-resolution ultrasound images were used to measure the flow-mediated dilation (FMD; endothelium dependent) and nitroglycerin-induced dilation (NID; endothelium independent) of the brachial artery. Laser Doppler perfusion imaging was used to measure vascular reactivity in the forearm skin. Left ventricular function was evaluated using transthoracic echocardiogram. At the end of the 6-month period, a worsening in endothelium-dependent skin vasodilation (P = 0.02) and rise in endothelin levels (P = 0.01) were found in the vitamin E compared with the placebo group. At the end of the 12-month period, a worsening was observed in NID (P = 0.02) and a marginal worsening was seen in systolic blood pressure (P = 0.04) and FMD (P = 0.04) in the vitamin E compared with the placebo group. In addition C-reactive protein levels decreased marginally in the vitamin E compared with the placebo group (P = 0.05). No changes were observed in left ventricular function. We concluded that long-term treatment with 1,800 IU of vitamin E has no beneficial effects on endothelial or left ventricular function in diabetic patients. Because vitamin E-treated patients had a worsening in some vascular reactivity measurements when compared with control subjects, the use of high dosages of vitamin E cannot be recommended.
Adult↗
Beta-cell failure in the pathogenesis of type 2 diabetes mellitus.
Type 2 diabetes is the result of a progressive impairment of pancreatic beta-cell function in the setting of worsening insulin resistance. Studies in high-risk populations have demonstrated that during progression to diabetes, beta cells have declining function and lose the first phase of insulin secretion, resulting in less than adequate suppression of hepatic glucose production following meals. In addition, oscillations of insulin secretion become unmatched from their normal coupling with glucose. Several mechanisms are thought to be responsible for impaired beta-cell function, including glucose toxicity and lipotoxicity, and potentially contribute to beta-cell loss. Advances in molecular science have elucidated several cytokines and transcription factors possibly implicated in the loss of beta-cell mass. In the past 15 years, clinical trials have given hope for potential therapies that may either delay or prevent the progression to diabetes. Lifestyle modification and pharmaceutical treatment remain the most promising interventions.
Blood Glucose↗
Kidney oxygenation during water diuresis and endothelial function in patients with type 2 diabetes and subjects at risk to develop diabetes.
The aim of the present study was to examine the relationship among water diuresis-induced changes in renal oxygenation, endothelial function, and various metabolic parameters in type 2 diabetic patients and healthy subjects at risk of type 2 diabetes. Thirty-eight subjects with type 2 diabetes (D: age, 54 +/- 10 years, mean +/- SD, 24 men) and 7 healthy subjects with parental history of type 2 diabetes or with impaired glucose tolerance (IGT) (relatives [R]: age 46 +/- 11 years, 4 men) were included. Laser Doppler imaging scanning was used to measure vasodilatation in the forearm skin in response to iontophoresis of 1% acetylcholine (Ach) and 1% sodium nitroprusside (SNP), and ultrasound was used to measure the flow-mediated dilation (FMD) and nitroglycerin-induced dilation (NID) in the brachial artery. Renal oxygenation was assessed by magnetic resonance imaging (MRI) before and during water diuresis. A decrease in the magnetic parameter R2* implies an increase in oxygenation. Renal medullary oxygenation did not improve with diuresis in either group (D: -0.5 +/- 1.9, R: -0.4 +/- 2.1, P = not significant [NS]). The renal cortical oxygenation showed a small, but statistically significant, improvement after diuresis in the 2 groups (D: -0.6 +/- 1.1, R: -0.5 +/- 0.5, P <.05). There were no correlations between the change in cortical R2* (R2* post-minus R2* prewater diuresis) and the micro- and macrovascular reactivity. The postdiuresis renal cortical R2* was negatively correlated with both the Ach- and SNP-induced skin vasodilation (% change over baseline)(r = -.40, P <.01 and r = -.39, P <.05, respectively), while no correlation existed with the FMD and NID. The baseline renal cortical oxygenation was also negatively correlated with the SNP-induced skin vasodilation (r = -.36, P <.05) and positively correlated with the fasting plasma glucose, total cholesterol, and vascular cell adhesion molecule (VCAM) concentrations (r =.34, P <.05, r =.31, P <.05 and r =.37, P <.05, respectively). These preliminary findings suggest an association between the kidney cortical oxygenation and the skin microvascular reactivity, glycemia, and lipidemia. Water diuresis failed to produce an improvement in renal medullary oxygenation in both patients with diabetes and subjects at risk for diabetes.
Aged↗
Achieving weight and activity goals among diabetes prevention program lifestyle participants.
OBJECTIVE: The Diabetes Prevention Program (DPP) showed that intensive lifestyle intervention reduced the risk of diabetes by 58%. This paper examines demographic, psychosocial, and behavioral factors related to achieving weight loss and physical activity goals in the DPP lifestyle participants. RESEARCH METHODS AND PROCEDURES: Lifestyle participants (n = 1079; mean age = 50.6, BMI = 33.9, 68% female, and 46% from minority groups) had goals of 7% weight loss and 150 min/wk of physical activity. Goal achievement was assessed at the end of the 16-session core curriculum (approximately week 24) and the final intervention visit (mean = 3.2 years) as a function of demographic, psychosocial, and behavioral variables. RESULTS: Forty-nine percent met the weight loss goal and 74% met the activity goal initially, while 37% and 67%, respectively, met these goals long-term. Men and those with lower initial BMI were more likely to meet activity but not weight loss goals. Hispanic, Asian, and Native Americans were more likely to meet the long-term activity goals, and whites were more likely to meet the initial weight loss goal. In multivariate analyses, meeting the long-term weight loss goal and both activity goals increased with age, while psychosocial and depression measures were unrelated to goal achievement. Dietary self-monitoring was positively related to meeting both weight loss and activity goals, and meeting the activity goal was positively related to meeting the weight loss goal. Participants who met initial goals were 1.5 to 3.0 times more likely to meet these goals long-term. DISCUSSION: Success at meeting the weight loss and activity goals increased with age. Initial success predicted long-term success. Self-monitoring and meeting activity goals were related to achieving and sustaining weight loss.
Adult↗
Efficacy and tolerability of initial combination therapy with nateglinide and metformin in treatment-naïve patients with type 2 diabetes.
OBJECTIVE: To assess the efficacy and tolerability of the combination of nateglinide (120 mg, ac) and metformin (500 mg, tid) as initial treatment in drug-naïve patients with type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS: This study reports data from the treatment-naïve (TN) subgroup of patients in a previously published, randomized, multicenter, placebo-controlled, 24- week trial that compared nateglinide, metformin, and the combination therapy (CT) in 701 patients with T2DM with baseline HbA(1c) between 6.8% and 11.0%. Of the 401 TN patients, 104, 104, 89, and 104 patients received nateglinide (120 mg, ac), metformin (500 mg, tid), CT, and placebo, respectively. The baseline characteristics of each group were similar, with mean age, BMI, duration of diabetes, HbA(1c), and fasting plasma glucose (FPG) levels of approximately 58 years, 30 kg/m(2), 4 Gastrointestinal side effects occurred in 27% of years, 8.2%, and 10.2 mmol/L, respectively. RESULTS: In patients receiving initial CT, HbA(1c) decreased substantially (Delta = -1.6 +/- 0.1%, p < 0.0001 vs. baseline or placebo) from a mean baseline of 8.2 +/- 0.1%, an effect significantly greater than the 0.8% reduction observed with both monotherapies (p < 0.001); whereas, in placebo-treated patients, HbA(1c) increased modestly (Delta = +0.3 +/- 0.1%, p < 0.05) from an identical baseline value. Seventy percent of CT-treated patients achieved a target HbA(1c) of < 7.0%. Both fasting plasma glucose (FPG) and the 2-hour postprandial glucose excursion (PPGE) after a liquid meal challenge decreased by 2.3 mmol/L in patients receiving CT, while the changes from baseline values in FPG and PPGE were +0.2 +/- 0.3 mmol/L and -0.5 +/- 0.2 mmol/L, respectively, in placebo-treated patients. The incremental 30-minute post-load insulin levels increased by 88 +/- 32 pmol/L (p = 0.006) in patients receiving CT and did not change significantly in placebo-treated patients. patients receiving CT (vs. 27.9% in the metformin monotherapy, and 14.4% in the placebo groups). Confirmed hypoglycemia (glucose <or= 2.8 mmol/L) occurred in 3.4% of patients receiving CT. CONCLUSIONS: Initial CT with the rapid-acting insulinotropic agent, nateglinide, and metformin, an agent with insulin-sensitizing effects in the liver and periphery, is a safe and effective means of achieving glycemic targets in TN patients with T2DM.
Cyclohexanes↗
The effects of atorvastatin on endothelial function in diabetic patients and subjects at risk for type 2 diabetes.
We have investigated the effect of atorvastatin on the endothelial function of patients with diabetes and subjects at risk for type 2 diabetes in a 12-wk, prospective, randomized, placebo-controlled, double-blind clinical trial. The flow- mediated dilation (FMD; endothelium dependent) and nitroglycerin-induced dilation (endothelium independent) in the brachial artery and the vascular reactivity at the forearm skin were measured. FMD improved in the atorvastatin-treated, at-risk subjects [median (25-75 percentile), 7.2% (2.9-9.6%) at exit visit vs. 6.6% (2.9-9.5%) at baseline; P < 0.05]. A similar improvement of FMD was found in atorvastatin-treated diabetic patients [median (25-75 percentile), 5.6 (3.9-7.9) at exit visit vs. 4.2 (3.2-7.2) at baseline; P = 0.07]. No changes were observed in nitroglycerin-induced dilation and the microcirculation reactivity measurements in either group. In the at-risk group, there was a decrease in the C-reactive protein [median (25-75 percentile), 0.12 mg/dl (0.07-0.27 mg/dl) at exit visit vs. 0.24 mg/dl (0.07-0.35 mg/dl) at baseline; P < 0.05] and TNF alpha [median (25-75 percentile), 2.6 pg/ml (1.8-4.1 pg/ml) at exit visit vs. 4.4 pg/ml (3.6-6.0 pg/ml) at baseline; P < 0.05] in the atorvastatin-treated patients, whereas in the diabetes group, a decrease in endothelin-1 (mean +/- SD, 0.97 +/- 0.29 pg/ml at exit visit vs. 1.19 +/- 0.42 pg/ml at baseline; P < 0.05) and plasminogen activator inhibitor-1 [median (25-75 percentile), 18 ng/ml (9-24 ng/ml) at exit visit vs. 27 ng/ml (7-41 ng/ml) at baseline; P < 0.05] were observed. We conclude that atorvastatin improves endothelial function and decreases levels of markers of endothelial activation and inflammation.
Adult↗
Thiazolidinedione use, fluid retention, and congestive heart failure: a consensus statement from the American Heart Association and American Diabetes Association.
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Edema↗
Circulating adiponectin and resistin levels in relation to metabolic factors, inflammatory markers, and vascular reactivity in diabetic patients and subjects at risk for diabetes.
OBJECTIVE: Adiponectin and resistin, two recently discovered adipocyte-secreted hormones, may link obesity with insulin resistance and/or metabolic and cardiovascular risk factors. We performed a cross-sectional study to investigate the association of adiponectin and resistin with inflammatory markers, hyperlipidemia, and vascular reactivity and an interventional study to investigate whether atorvastatin mediates its beneficial effects by altering adiponectin or resistin levels. RESEARCH DESIGN AND METHODS: Associations among vascular reactivity, inflammatory markers, resistin, and adiponectin were assessed cross-sectionally using fasting blood samples obtained from 77 subjects who had diabetes or were at high risk to develop diabetes. The effect of atorvastatin on adiponectin and resistin levels was investigated in a 12-week-long randomized, double-blind, placebo-controlled study. RESULTS: In the cross-sectional study, we confirm prior positive correlations of adiponectin with HDL and negative correlations with BMI, triglycerides, C-reactive protein (CRP), and plasma activator inhibitor (PAI)-1 and report a negative correlation with tissue plasminogen activator. The positive association with HDL and the negative association with PAI-1 remained significant after adjusting for sex and BMI. We also confirm prior findings of a negative correlation of resistin with HDL and report for the first time a positive correlation with CRP. All of these associations remained significant after adjusting for sex and BMI. No associations of adiponectin or resistin with any aspects of vascular reactivity were detected. In the interventional study, atorvastatin decreased lipid and CRP levels, but adiponectin and resistin were not specifically altered. CONCLUSIONS: We conclude that adiponectin is significantly associated with inflammatory markers, in part, through an underlying association with obesity, whereas resistin's associations with inflammatory markers appear to be independent of BMI. Lipid profile and inflammatory marker changes produced by atorvastatin cannot be attributed to changes of either adiponectin or resistin.
Adiponectin↗
Thiazolidinedione use, fluid retention, and congestive heart failure: a consensus statement from the American Heart Association and American Diabetes Association. October 7, 2003.
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Blood Volume↗
Exercise in the management of type 1 diabetes mellitus.
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Diabetes Mellitus, Type 1↗
Effect of lifestyle modification on adipokine levels in obese subjects with insulin resistance.
OBJECTIVE: To study the effect of weight loss in response to a lifestyle modification program on the circulating levels of adipose tissue derived cytokines (adipokines) in obese individuals with insulin resistance. RESEARCH METHODS AND PROCEDURES: Twenty-four insulin-resistant obese subjects with varying degrees of glucose tolerance completed a 6-month program consisting of combined hypocaloric diet and moderate physical activity. Adipokines [leptin, adiponectin, resistin, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6)] and highly sensitive C-reactive protein were measured before and after the intervention. Insulin sensitivity index was evaluated by the frequently sampled intravenous glucose tolerance test. RESULTS: Participants had a 6.9 +/- 0.1 kg average weight loss, with a significant improvement in sensitivity index and reduction in plasma leptin (27.8 +/- 3 vs. 23.6 +/- 3 ng/mL, p = 0.01) and IL-6 (2.75 +/- 1.51 vs. 2.3 +/- 0.91 pg/mL, p = 0.012). TNF-alpha levels tended to decrease (2.3 +/- 0.2 vs. 1.9 +/- 0.1 pg/mL, p = 0.059). Adiponectin increased significantly only among diabetic subjects. The reductions in leptin were correlated with the decreases in BMI (r = 0.464, p < 0.05) and with changes in highly sensitive C-reactive protein (r = 0.466, p < 0.05). DISCUSSION: Weight reduction in obese individuals with insulin resistance was associated with a significant decrease in leptin and IL-6 and a tendency toward a decrease in circulating TNF-alpha, whereas adiponectin was increased only in diabetic subjects. Further studies are needed to elucidate the relationship between changes of adipokines and the health benefits of weight loss.
Adiponectin↗
The effects of troglitazone, an insulin-sensitizing agent, on the endothelial function in early and late type 2 diabetes: a placebo-controlled randomized clinical trial.
Activation of the peroxisome proliferator-activator receptor gamma (PPARgamma) improves insulin resistance and glycemic control in patients with diabetes. As PPARgamma is expressed in the endothelial cell, we have investigated the effect of troglitazone, a PPARgamma activator, on the endothelial function in people with type 2 diabetes in a 12-week, prospective, randomized, double-blinded clinical trial. We studied 87 type 2 diabetic patients who were divided into 3 groups. Group A consisted of 27 patients with recently diagnosed diabetes and no clinical manifestations of macrovascular disease; group B, 29 patients with long-term diabetes and no clinically evident macrovascular disease; and group C, 31 diabetic patients with documented macrovascular disease (cardiovascular, cerebrovascular, or peripheral vascular disease). High-resolution ultrasound images were used to measure the flow-mediated dilation (FMD, endothelium-dependent) and nitroglycerin-induced dilation (NID, endothelium-independent) in the brachial artery. Laser Doppler perfusion imaging was used to measure vasodilation in the forearm skin in response to iontophoresis of 1% acetylcholine (Ach, endothelium-dependent) and 1% sodium nitroprusside (NaNP, endothelium-independent). The plasma concentrations of von Willebrand factor (vWF), soluble intercellular adhesion molecule (sICAM), and soluble vascular cell adhesion molecule (sVCAM) were also measured as indicators of endothelial cell activation. The FMD improved in the troglitazone-treated patients in group A (7.72 +/- 3.4 v 5.27 +/- 2.0, P <.05 [exit visit v baseline, percent of increase in brachial artery diameter, mean +/- SD]). The fasting insulin level also improved in this group (15.6 +/- 10 v 19.7 +/- 10, P <.05) and was strongly correlated to changes in FMD (r = -.73, P <.01). No changes were found in the FMD or the fasting insulin levels in the troglitazone-treated patients in groups B or C. The NID was not changed by troglitazone treatment in any of the 3 groups. Also, no differences were found in the microcirculation reactivity measurements or in the biochemical markers of endothelial dysfunction in all 3 groups. A small, but significant, improvement of the FMD was found in placebo-treated patients in group B, probably related to the low FMD levels at baseline in the patients (5.40 +/- 3.0 v 4.36 +/- 2.4, P <.05). We concluded that troglitazone treatment for 12 weeks improved endothelial function in the macrocirculation of patients with recently diagnosed type 2 diabetes and no clinical evidence of macrovascular disease. This improvement was strongly associated with the improvement of fasting plasma insulin concentrations.
Chromans↗
Lifestyle modification improves endothelial function in obese subjects with the insulin resistance syndrome.
OBJECTIVE: Endothelial dysfunction has been reported in type 2 diabetic patients and in obese subjects with insulin resistance syndrome (IRS). This study evaluates the effects of weight reduction and exercise on vascular reactivity of the macro- and the microcirculation in obese subjects with IRS. RESEARCH DESIGN AND METHODS; We studied 24 obese subjects (9 men and 15 women, age 49.3 +/- 1.9 years, BMI 36.7 +/- 0.94 kg/m(2), mean +/- SEM) with IRS at baseline and after 6 months of weight reduction and exercise. Brachial artery flow-mediated dilation (FMD) and response to sublingual glyceryltrinitrate (GTN) were assessed by high-resolution ultrasound. Microvascular reactivity was evaluated by the laser-Doppler perfusion imaging after iontophoresis of acetylcholine and sodium nitroprusside. We also measured plasma levels of soluble intercellular adhesion molecule (sICAM), vascular adhesion molecule, von Willebrand factor, plasminogen activator inhibitor-1 (PAI-1) antigen, and tissue plasminogen activator antigen. RESULTS: This intervention resulted in 6.6 +/- 1% reduction in body weight (P < 0.001) and significant improvement of insulin sensitivity index (2.9 +/- 0.36 vs. 1.9 +/- 0.33 [10(-4) x min(-1) x ( microU ml(-1))], P < 0.001). FMD significantly improved (12.9 +/- 1.2% vs. 7.9 +/- 1.0%, P < 0.001), whereas response to GTN and microvascular reactivity did not change. Similar observations were seen when the subjects were subclassified according to their glucose tolerance to normal glucose tolerance, impaired glucose tolerance, and type 2 diabetes. sICAM and PAI-1 significantly decreased (251.3 +/- 7.7 vs. 265.6 +/- 9.3 ng/ml, P = 0.018 and 36.2 +/- 3.6 vs. 48.6 +/- 3.9 ng/ml, P = 0.001, respectively). The relationship between percentage weight reduction and improved FMD was linear (R(2) = 0.47, P = 0.001). CONCLUSIONS: We conclude that 6 months of weight reduction and exercise improve macrovascular endothelial function and reduces selective markers of endothelial activation and coagulation in obese subjects with IRS regardless of the degree of glucose tolerance.
Blood Flow Velocity↗
Poly(ADP-Ribose) polymerase is activated in subjects at risk of developing type 2 diabetes and is associated with impaired vascular reactivity.
BACKGROUND: We have previously shown that endothelial function is impaired not only in diabetes but also in subjects at risk of developing type 2 diabetes. We hypothesized that changes in the expression or activity of the endothelial isoform of nitric oxide synthase (eNOS), the receptor for advanced glycation end products (RAGE), and poly(ADP-ribose) polymerase (PARP) are related to this impairment. METHODS AND RESULTS: We included a control group of 21 healthy subjects, a group of 22 healthy individuals with parental history of type 2 diabetes, a group of 23 subjects with impaired glucose tolerance, and a group of 21 type 2 diabetic patients. Two 2-mm forearm skin biopsies were taken from each participant and used for measurements. The percentage of PARP-positive endothelial nuclei was higher in the group with parental history of type 2 diabetes and diabetic patients compared with the controls (P<0.001). Immunoreactivity for nitrotyrosine (a marker of reactive nitrogen species) was higher in the diabetic group compared with all other groups (P<0.01). No differences in the expression of eNOS and RAGE were found among all 4 groups. The polymorphism of the eNOS gene was also studied and was not found to influence eNOS expression or microvascular functional measurements. CONCLUSIONS: PARP activation is present in healthy subjects at risk of developing diabetes as well as in established type 2 diabetic patients, and it is associated with impairments in the vascular reactivity in the skin microcirculation.
Acetylcholine↗