Adipose Insulin Resistance and Circulating Betatrophin Levels in Women with PCOS

Abstract

The role of IR and metabolic disorders has become a crucial topic of study in the pathogenesis of PCOS. Adipose tissue is an important target organ of insulin, and adipose IR plays an important role in the occurrence and development of PCOS. This study seeks to investigate the role of adipose IR in the development of PCOS and to examine its relationship with circulating betatrophin levels in women with PCOS. A cross-sectional analysis of a cohort of women with PCOS and healthy women was performed in this study. Serum betatrophin concentrations were measured by ELISA. Adipose IR was calculated using the product of fasting insulin and FFA concentrations, and the relationship between adipose IR, circulating betatrophin, and other parameters was analyzed. Adipose IR in women with PCOS was significantly higher than that in controls. We found that women with PCOS who have adipose IR (adipose IR ≥ 55) have a higher BMI and higher blood glucose, insulin, PRL, FFA, TG, HOMA-_IR, AUC_glucose, AUC_insulin, VAI_female, and BAI levels than PCOS-afflicted women without adipose IR, while M-values, and SHBG and LH levels were lower. In women with PCOS, serum betatrophin levels were significantly increased compared with controls. Adipose IR negatively correlated with M values and positively with circulating betatrophin levels in the study population. After metformin treatment, circulating betatrophin levels and adipose IR in women with PCOS were significantly decreased compared with pretreatment. Adipose IR is associated with betatrophin levels in women with PCOS. The combination of adipose IR and circulating betatrophin measurements may be significant for screening patients with PCOS.

Figure 1

Adipose IR and clinical features in the study population. (a) The curve of adipose IR distribution with age in the study population. (b) Adipose IR levels in normal and PCOS patients. (c) M values in normal and PCOS patients with or without adipose IR. (d) FAI in normal and PCOS patients with or without adipose IR. (e) Circulating betatrophin levels in normal and PCOS patients with or without adipose IR. Values were given as median (interquartile range). ^∗p < 0.05, ^∗∗p < 0.01 compared with controls. ^▲p < 0.05,^△p < 0.01 compared with PCOS patients without adipose IR.

Figure 2

Adipose IR levels and ROC curve analysis in study population (a) Prevalence of elevated PCOS in different quartiles of adipose IR : Q1, <21.86; Q2, 21.86–33.62; Q3, 33.62–63.42; and Q4, >63.42 (vs. Q1: ^∗∗p < 0.01. (b) Prevalence of elevated adipose IR in different quartiles of betatrophin: Q1, <0.30 μg/L; Q2, 0.30–0.44 μg/L; Q3, 0.44–0.62 μg/L; and Q4, >0.62 μg/L (vs. Q1: ^∗∗p < 0.01). (c) ROC curve analyses for the prediction of PCOS according to the adipose IR levels. (d) ROC curve analyses for the prediction of IR (M values) according to the adipose IR levels.

Figure 3

Adipose IR and circulating betatrophin levels in PCOS patients after both 3 and 6 months of metformin treatment. Values were given as median (interquartile range). ^∗p < 0.05, ^∗∗p < 0.01 vs. baseline.