Association of kallistatin with carotid intima-media thickness in women with polycystic ovary syndrome.

Background: Kallistatin is a secreted protein that acts as a tissue kallikrein inhibitor. It has anti-inflammatory, antioxidant and vasoprotective properties. Polycystic ovary syndrome (PCOS) is a reproductive and metabolic disease associated with low-grade chronic inflammation and multiple risk factors for cardiovascular diseases. The aims of this study were to ascertain whether circulating kallistatin levels are altered in women with PCOS, and whether there is an association between kallistatin and carotid intima-media thickness (cIMT) as well as inflammatory markers high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor-α (TNF-α).

Methods: This cross-sectional study included 75 women with PCOS and 75 age- and BMI-matched controls without PCOS. Circulating kallistatin and TNF-α levels were measured using ELISA. Metabolic and hormonal parameters, hs-CRP levels and cIMT were also determined. All subjects underwent the 2-hour oral glucose tolerance test (2-h OGTT).

Results: Circulating kallistatin levels were significantly elevated in women with PCOS compared to controls (6.31±2.09 vs. 4.79±2.26 ng/mL, P<0.001). Inflammatory markers hs-CRP and TNF-α were found to be elevated in women with PCOS. Kallistatin levels positively correlated with insulin, insulin resistance index (HOMA-IR), free androgen index, hs-CRP, TNF-α and cIMT in both PCOS and control groups. Kallistatin levels did not show correlation with BMI, blood pressure, fasting blood glucose, 2-h OGTT or HbA1c. Multiple linear regression analysis revealed that kallistatin is an independent predictor for cIMT (β=0.131, 95% CI: 0.114-0.150, P=0.019).

Conclusions: Kallistatin levels may provide useful information regarding cardiovascular risk in women with PCOS.