[Activity of Vegetative Nervous System and Levels of Inflammatory Cytokines During Glucose Tolerance Test in Subjects...

Fourteen patients with high normal (main group) and 15 subjects with optimal (control group) blood pressure (BP) were examined. Fasting and postprandial (60 and 120 min after oral intake of glucose) levels of glucose, insulin, interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and C-reactive protein were measured. At the same time spectral analysis of heart rate variability (HRV) was done. Body mass index (BMI) and insulin resistance index (as HOMA-IR) were calculated. In patients with high normal BP total power of HRV was decreased (p < 0.05) and dynamic changes of HRV after glucose loading were blunted. In persons with optimal BP transient elevation of low frequency component and low/high ratio in 60 min after onset of glucose tolerance test (GTT) were registered; values of both parameters were higher than in the main group (p < 0.05). Changes in vegetative nervous system activity in control group were accompanied by transient elevations of levels of inflammatory cytokines: IL-10 and TNF-α in 60 min, IL-6 in 120 min after GTT onset (p < 0.05), which at that moment were higher than in patients with high normal BP (p < 0.05). Fasting and postprandial insulin concentrations and glucose level 60 min after glucose intake were higher in patients from the main group (p < 0.05). In both groups positive correlations between BMI and HOMA-IR were observed (r1 = 0.70 & r2 = 0.78). Subjects with optimal and high normal BP have different variants of vegetative nervous system reactions to pulsatile hyperglycemia which is accompanied by changes of levels of inflammatory cytokines and worsening of carbohydrate metabolism in patients with high normal BP.