Comparison of plasma viscosity as a marker of endothelial dysfunction with nitric oxide and asymmetric dimethylarginine in subjects with dyslipidemia

OBJECTIVE: In this study, we aimed to investigate the alterations in plasma viscosity and whether there was a relationship between plasma viscosity and endothelial dysfunction markers such as nitric oxide (NOx), asymmetric dimethylarginine(ADMA) and oxidized Low Density Lipoprotein (oxLDL) in dyslipidemic subjects

The relationship between plasma asymmetrical dimethyl-L-arginine and inflammation and adhesion molecule levels in subjects with normal, impaired, and diabetic glucose tolerance

Increasing evidence suggests that the postprandial state is a contributing factor to the development of atherosclerosis. To evaluate the effects of acute hyperglycemia on endothelial dysfunction and inflammation, plasma asymmetrical dimethyl-L-arginine (ADMA), intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1, and C-reactive protein (CRP) levels and secretory phospholipase A, (sPLA,) activities were measured in subjects with normal (n = 35), impaired (IGT) (n = 25), and diabetic (DGT) (n = 20) glucose tolerance. At baseline, plasma ADMA, sICAM-1, and CRP concentrations and plasma sPLA(2) activities were higher in both the IGT and DGT groups than in the normal glucose tolerance group (for each comparison, each P <.001). Patients with DGT have higher plasma ADMA and sICAM-1 concentrations than patients with IGT (for each, P <.001). Two hours after glucose loading, plasma ADMA and CRP concentrations and sPLA, activities were significantly elevated in the 3 groups when compared with baseline levels (for each comparison, P <.001). Plasma vascular cell adhesion molecule 1 and sICAM-1 concentrations were found to be elevated from baseline levels after glucose loading in the IGT and DGT groups (for each comparison, P <.001). Correlation analysis at baseline suggested that there was a significant relationship between ADMA and inflammation and soluble adhesion markers in the studied groups. In conclusion, plasma concentrations of ADMA and of inflammation and adhesion molecules were elevated in the prediabetic state. A complex interrelation could exist between ADMA and inflammation, and mechanisms involved in endothelial dysfunction are multifactorial at the prediabetic and diabetic state. (C) 2008 Elsevier Inc. All rights reserved

Serum oxidized low density lipoprotein, paraoxonase 1 and lipid peroxidation levels during oral glucose tolerance test

Increasing evidence suggests that the postprandial state is a contributing factor to the development of atherosclerosis. To evaluate the effects of acute hyperglycemia on the oxidative stress, concentrations of serum-oxidized low density lipoprotein (oxLDL), paraoxonase 1 (PON1), and thiobarbituric acid reactive substances (TBARS) were measured in subjects with normal glucose tolerance (NGT) (n = 35), impaired glucose tolerance (IGT) (n = 25), and diabetic glucose tolerance (DGT) (n = 20). In NGT group, the 2 hours' TBARS and oxLDL levels were not statistically different when compared to baseline, and 2 hours' PON1 activities were higher when compared to baseline (p<0.01). Subjects with IGT and DGT have higher 2 hours' serum TBARS and oxLDL levels than their baseline levels (p<0.01, for each). Baseline oxLDL levels of both IGT and DGT groups were higher than NGT group (p<0.01 and p<0.01, respectively). While there were not any significant differences in 2 hours' versus baseline PON1 activities in the IGT group, the 2 hours' versus baseline PON1 activities in the DGT group were significantly lower (p<0.01). The postchallenge 2 hours' PON1 activities of both IGT and DGT groups were lower than NGT group (p<0.01 and p<0.01, respectively). Baseline oxLDL was positively correlated with 2 hours' glucose (r = 0.613, p<0.01) in IGT and DGT groups. PON1 activities were correlated with HDL-cholesterol, total cholesterol, and fasting glucose (r = 0.680, r = 0.698 and r = 0.431, respectively, for each p<0.01) in NGT. In conclusion, oxidative stress occurs at an early stage in diabetes, and protective effects of HDL against atherosclerosis may be dependent on the PON1 activities