Altered Circulating Inflammatory Cytokines Are Associated with Anovulatory Polycystic Ovary Syndrome (PCOS) Women Resistant to Clomiphene Citrate Treatment

BACKGROUND: Polycystic ovary syndrome (PCOS) is a common gynecological disease characterized by chronic oligoanovulation, clinical/biochemical hyperandrogenism, polycystic ovaries, and insulin resistance. Accumulating evidence has shown that PCOS-related ovarian dysfunction is the main cause of anovulatory infertility. Clomiphene citrate (CC) is the first-line therapy for PCOS patients; however, approximately 15–40% PCOS patients are resistant to CC treatment. It has been demonstrated that PCOS is a chronic pro-inflammatory state, as some pro-inflammatory cytokines were elevated in the peripheral circulation of PCOS patients, but whether altered inflammatory cytokines expression in PCOS patients is associated with blunted response to CC remains unknown. MATERIAL/METHODS: We recruited 44 CC-resistant PCOS patients, along with 55 age and body mass index (BMI)-matched CC-sensitive PCOS patients. Ovulation was induced by administrating 50–100 mg/day CC on days 5 to 9 of each menstrual cycle. The cytokine profiles were detected by cytokine antibody microarrays and further validated by ELISAs. RESULTS: CC-resistant patients had higher levels of high-sensitivity C-reactive protein (hsCRP) than the CC-sensitive individuals. A growth factor, angiopoietin-2, was significantly reduced [1.64 (0.93–1.95) vs. 1.08 (0.85–1.34), p<0.05], while a chemokine CXCL-16 was significantly increased (9.10±2.35 vs. 10.41±2.82, p<0.05) in CC-resistant patients compared to the CC-sensitive subjects. CXCL-16 was positively correlated with hsCRP (r=0.33, p<0.01). Logistic regression analysis showed that angiopoietin-2 and CXCL-16 are associated with CC resistance. CONCLUSIONS: Circulating cytokines are disturbed in CC-resistant PCOS patients. Altered angiopoietin-2 and CXCL-16 levels might compromise the responsiveness of the ovary to CC through up-regulating angiogenesis and inflammation.