Hypoadiponectinemia is associated with
insulin resistance. However, there is very limited information about the relationship between plasma
adiponectin and cardiac autonomic nervous function. We tested the hypothesis that
hypoadiponectinemia is associated with cardiac sympathetic overactivity in patients with
type 2 diabetes mellitus. Thirty-three male type 2 diabetic patients not on
insulin treatment were classified into a
hypoadiponectinemia group (plasma
adiponectin concentration, <4.0 microg/mL; age, 58.6 +/- 8.6 years [mean +/- SD]; n = 14) and an age-matched normoadiponectinemia group (serum
adiponectin concentration, >/=4.0 microg/mL; age, 58.2 +/- 8.1 years; n = 19). In each patient, baroreflex sensitivity, heart rate variability, plasma
norepinephrine concentration, and cardiac (123)I-metaiodobenzylguanidine (
MIBG) scintigraphic findings were assessed. Compared with the normoadiponectinemia group, the
hypoadiponectinemia group had a higher body mass index (P < .01), higher plasma concentrations of
glucose and
insulin (P < .05 and P < .01, respectively), higher homeostasis model assessment of
insulin resistance (HOMA-IR) values (P < .005), higher plasma
triglyceride levels (P < .05), and lower plasma
high-density lipoprotein cholesterol levels (P < .05). In the
hypoadiponectinemia group, the autonomic function measurements included a lower baroreflex sensitivity (P< .05) and a lower delayed myocardial uptake of (123)I-MIBG (P < .01) with a higher washout rate (P < .05). Multiple regression analysis revealed that the plasma
adiponectin level was independently associated with HOMA-IR (F = 9.916) and the percent washout rate of (123)I-MIBG (F = 5.985). Our results suggest that in middle-aged men with
type 2 diabetes mellitus,
hypoadiponectinemia is associated with cardiac sympathetic overactivity as determined by (123)I-MIBG scintigraphy.