The relationship between circulating irisin levels and endothelial function in lean and obese subjects.
OBJECTIVE
Irisin has been shown to turn white adipocytes into brown-like adipocytes, which is emerging as an appealing therapeutic target for obesity. The objective of the study was to determine whether circulating irisin levels are related to endothelial dysfunction in obese subjects.


METHODS
A total of 41 nonhypertensive, nondiabetic obese subjects and 40 age- and sex-matched lean healthy control were involved in this study. Clinical characteristics, blood biochemistry, circulating irisin and adiponectin of the subjects were measured. Endothelium-dependent vasodilation (EDV) and endothelial-independent vasodilation (EIV) were determined using high-resolution ultrasound.


RESULTS
Circulating irisin and adiponectin were significantly lower in obese subjects compared with lean healthy control (P < 0·05). Endothelial function was impaired in obese subjects (maximum EDV: 8·95 ± 3·46% vs 14·56 ± 3·90%, P < 0·05). Bivariate correlation analysis revealed that circulating irisin was positively correlated with EDV(r = 0·388, P < 0·01) and negatively correlated with BMI (r = -0·281, P < 0·05), waist circumference (r = -0·298, P < 0·01), free fatty acid (FFA) (r = -0·289, P < 0·01), high-sensitivity C-reactive protein (hs-CRP) (r = -0·244, P < 0·05) and malondialdehyde (r = -0·258, P < 0·05). Multiple regression analysis revealed that circulating irisin, adiponectin, FFA and BMI were independently associated with EDV after adjusting for covariates (R(2) = 0·457, F = 8·766, P = 0·000).


CONCLUSIONS
Circulating irisin level was decreased in nonhypertensive, nondiabetic obese subjects compared with lean healthy control. Lower levels of irisin are independently associated with endothelial dysfunction. Therefore, irisin may be involved in the regulation of endothelial function in obesity.
Department of Endocrinology, Affiliated Hospital of Weifang Medical University, Weifang, China.
Ningning
N
Hou
Department of Pathology, Affiliated Hospital of Weifang Medical University, Weifang, China.
Fang
F
Han
Department of Endocrinology, Affiliated Hospital of Weifang Medical University, Weifang, China.
Xiaodong
X
Sun
D052242:Adiponectin / Q000097:blood; D000328:Adult; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood* / Q000503:physiopathology*; D012044:Regression Analysis; D014280:Triglycerides / Q000097:blood; D014664:Vasodilation / Q000502:physiology*; D055105:Waist Circumference; D055815:Young Adult
D052242:Adiponectin; C577593:FNDC5 protein, human; D005230:Fatty Acids, Nonesterified; D005353:Fibronectins; D007328:Insulin; D014280:Triglycerides; D008315:Malondialdehyde; D002097:C-Reactive Protein