Young Men With High-Normal Blood Pressure Have Lower Serum Adiponectin, Smaller LDL Size, and Higher Elevated Heart Rate Than Those With Optimal Blood Pressure

Abstract

OBJECTIVE -Three measures-heart rate, a global index of the influence of the autonomic nervous system on the heart; circulating concentrations of adiponectin, an adipose-specific protein; and C-reactive protein (CRP), a sensitive marker of inflammation-have been reported to be closely associated with insulin resistance. Patients with borderline hypertension are known to be more insulin resistant and dyslipidemic than those with normal blood pressure (BP). BP can be classified into three categories: optimal, normal, and high-normal. The present study examined whether those with high-normal BP have any of these three conditions as compared with those with optimal BP in young healthy men.RESEARCH DESIGN AND METHODS -Anthropometric, blood pressure, heart rate, and blood tests, including tests for adiponectin and CRP, were conducted in 198 male students, ages 18 -26 years, who had fasted overnight. Insulin resistance (IR) and insulin secretion (␤-cell levels) were calculated using the homeostasis model assessment (HOMA), and LDL size was measured by PAGE.RESULTS -Compared with the 90 men who had optimal BP, the 46 men with high-normal BP had increased heart rate, BMI, percent body fat, and serum leptin levels. In addition, they had greater serum insulin, HOMA IR, and ␤-cell levels, lower adiponectin levels, and comparable CRP levels. Furthermore, the 46 men with high-normal BP had higher serum triglyceride and apolipoprotein (apo) B levels, and smaller LDL size; however, there was no difference in LDL and HDL cholesterol and apoA-I between men with optimal and high-normal BP. After adjusting for BMI, differences were still significant in serum adiponectin, heart rate, and LDL particle size. As BP rose, there was an increase in heart rate (BMI-adjusted least square means were 63, 65, and 70 bpm in men with optimal, normal, and high-normal BP, respectively; P ϭ 0.005), whereas serum adiponectin (7.5, 6.6, and 6.4 mg/l; P ϭ 0.007) and LDL particle size (271, 269, and 269 Å; P ϭ 0.008) decreased.CONCLUSIONS -Young men with high-normal BP have a faster heart rate, lower serum adiponectin levels, and smaller LDL size than men with optimal BP, even after adjustment for BMI. These results suggest the necessity of preventing further development of cardiac and metabolic diseases in young people who have high-normal BP. Diabetes Care 25:971-976, 2002

Relationship of adiponectin to body fat distribution, insulin sensitivity and plasma lipoproteins: evidence for independent roles of age and sex

“…In this study we found that both IAF and adiponectin were major correlates of plasma lipoproteins, in particular of LDL buoyancy (Rf) and HDL cholesterol concentrations, in keeping with other reports [31,34,64]. These relationships could be mediated by effects of adiponectin on hepatic lipase activity, which is increased in central obesity and insulin resistance states associated with the metabolic syndrome [65,66].…”

“…Circulating adiponectin concentrations are correlated with insulin sensitivity [30,31], with low concentrations predicting a future decrease in insulin sensitivity in Pima Indians [33]. Furthermore, low adiponectin concentrations have been associated with a more atherogenic lipid profile [34] and have been shown to increase with thiazolidinedione administration [35,36]. Studies in animals also suggest that adiponectin could be an important determinant of insulin action.…”

The role of total and high-molecular-weight complex of adiponectin in vascular function in offspring whose parents both had type 2 diabetes

“…Our study demonstrates that in offspring of diabetic parents HDL-cholesterol correlates highly with adiponectin, an association previously reported in healthy [13,14], obese [47] and type 2 diabetic subjects [48]. The link between HDL-cholesterol and EDV that we demonstrate is well established: multiple studies show low HDLcholesterol is highly predictive of endothelial dysfunction in healthy and diabetic subjects [49][50][51][52][53], and in experimental models where HDL-cholesterol is raised acutely, EDV normalises [58].…”

“…In brief, after an overnight fast and the collection of baseline samples, Dextrose 0.3 g/kg was administered intravenously, followed 20 min later by the intravenous infusion of insulin 0.03 U/kg (Humulin R; Eli Lilly, Indianapolis, IN, USA). Samples were collected for insulin and glucose at 2, 3, 4, 5,6,8,10,12,14,19,22,23,24,25,27,30,40,50,60,70,80, 90, 100, 120, 140, 160 and 180 min following the dextrose and analysed using the Bergman's Minimal Model, a computer-based method to assess plasma insulin and glucose dynamics during an IVGTT. The minimum model for glucose disposal and insulin dynamics yields assessments of insulin secretion and sensitivity, including the insulin sensitivity index (S I ) and the glucose effectiveness index (S G ) also known as insulin-independent glucose clearance.…”

“…Epidemiologically, serum levels of the protein correlate negatively with cardiac risk factors, positively with HDL-cholesterol and are lower in patients with coronary artery disease than in controls [13][14][15]. Adiponectin accumulates in rat carotid artery walls after balloon injury, but not in healthy vessel walls [16] and has been shown to suppress both the conversion of macrophages to foam cells and the migration of smooth muscle cells [6,17].…”