Obesity and insulin resistance appear to be associated with low-grade inflammation and endothelial dysfunction. Insulin resistance and endothelial dysfunction were improved by weight loss after LAGB.

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.

The aim of this study was to investigate whether there is a difference between Alzheimer disease (AD) dementia and pure vascular dementia (VaD) in relation to nitrosative stress levels. We determined serum nitric oxide (NO), oxidized low-density lipoproteins (ox-LDL), and 3-nitrotyrosine levels (3-NT) in healthy elderly individuals (controls, n=15, mean age=73.4+/-7.9 y), AD patients (n=30; mean age=71.2+/-12.7 y) and VaD patients (n=20; mean age=75.2+/-7.5 y). Patients were under anticholinesterase drug therapy. Our results showed that serum NO and ox-LDL levels in AD patients group were significantly higher than in both controls (P<0.001 and P<0.001) and VaD patients (P<0.01 and P<0.001). However, no significant differences in plasma NO and ox-LDL levels were found between VaD and controls. Our study did not reveal significant differences in plasma 3-NT values of dementia patients when compared with controls. There was a significant negative correlation between Mini-Mental State Examination score and serum NO levels in dementia patients (r=-0.349, P<0.01). Serum NO levels were also positively correlated with serum ox-LDL levels (r=0.358, P<0.01). In conclusion, elevation in serum levels of NO was present in probable AD patients but not in VaD patients, and this seems to be related to both ox-LDL levels and cognitive status.

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. MATERIAL AND METHOD: 35 subjects with normolipidemia and 30 subjects with hyperlipidemia were involved in this study. Dyslipidemia was defined as total cholesterol levels ≥200 mg/dL and/or triglyceride level ≥150 mg/dL. Plasma total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, triglycerides, total protein, albumin levels and NOx were determined by enzymatic methods using commercial kits. Plasma ADMA concentrations and serum levels of total oxLDL were determined by ELISA. Plasma viscosity was measured by Harkness capillary viscometer. RESULT: Plasma viscosity, ADMA and oxLDL values were significantly higher in subjects with dyslipidemia than in subjects with normolipidemia. Plasma NOx concentration was decreased in dyslipidemic subjects compared to the normo-lipidemic subjects. We found that fibrinogen had no effect upon plasma viscosity in selected patients with dyslipidemia. CONCLUSION: Our results demonstrated that the rheological impairment of dyslipidemic patients was related with endothelial dysfunction and this was a possible cause of both micro and macrovascular complications. Therefore, as plasma viscosity is also a sensitive parameter, it can add useful information about the diagnosis and treatment of various disorders, and it should be utilized more frequently in clinical medicine. M. Ercan et al. / Plasma viscosity and endothelial dysfunctionintervention. Hemorheology is the consequence of mechanical forces in the blood vessels and the link between blood mechanics and biochemical mechanisms.The vascular endothelium has been recognized to have a central importance in maintaining vascular homeostasis. Shear stress is a biomechanical force that is determined by blood flow, vessel geometry and fluid viscosity [8,13]. The ability of the vascular endothelium to sense and to respond to the blood flow correlates with the patterns of flow to which the cells are exposed. The blood vessel reacts to multiple chemical and mechanical stimuli in flowing blood; mechanical factors are principally pressure and shear stress. Wall shear stress is the drag force acting on the endothelial cells as a result of the flow [8,29]. Several vasodilators, including nitric oxide (NOx), prostaglandin and endothelium-derived relaxing factor are released by the endothelium in response to shear stress. An adaptive response of the endothelium to mechanical injury caused by changes in rheology of blood might play a role [13]. The rheology (i.e. flow behavior) of a fluid can physically be described by its viscosity. Viscosity can be defined as the resistance of fluids against flow and attempts to alter their shape.Plasma viscosity is a major determinant of capillary blood flow through ...