Lipocalin-2 Level in Patients with Polycystic Ovary Syndrome: Association with Insulin Resistance and Metformin Therapy

Abstract

Abstract Background PCOS appears to be associated with an increased risk of metabolic aberrations, including insulin resistance and hyperinsulinemia, type 2 diabetes mellitus, dyslipidemia, and cardiovascular disease throughout womens’ lifespan. Obesity is a state of chronic low-grade systemic inflammation. This chronic inflammation is characterized by abnormal cytokine production and activation of inflammatory signaling pathways in adipose tissues, which contributes to insulin resistance and its related diseases such as PCOS and metabolic syndrome. Objective To evaluate Lipocalin-2 level in a sample of Egyptian females with PCOS and study the effect of metformin therapy on Lipocalin-2 level in patients with PCOS. Methods This case control study was conducted on 52 females, collected from the outpatient obstetrics and gynaecology clinics of Ain Shams University Hospitals from June 2018 to March 2019, their age ranged between 17-43 years old. divided into 2 groups: Group (I) 32 women with polycystic ovary syndrome According to the Rotterdam diagnostic criteria of PCOS, and Group (II) 20 healthy women old with normal ovulatory cycle as a control group. All subjects were subjected to full medical history taking, thorough physical examination including BMI and waist circumference. Fasting plasma glucose, Fasting s.insulin, HOMA-IR, lipocalin-2 level were assessed. Results Serum lipocalin-2 levels did not differ between patients with PCOS and BMI-matched healthy controls (P-value 0.193), and there was no significant difference between the 2 studied groups as regard HOMA-IR (p = 0.375). Metformin therapy for 3 months in patients with PCOS in the present study, resulted in significant reduction in lipocalin-2 level (p-value<0.01), (mean 54.2±15.3ng/ml before metformin therapy vs 42.9±14.2 ng/ml after metformin therapy). Moreover, metformin therapy in PCOS group resulted in significant reduction in weight, BMI, waist circumference and HOMA-IR. Furthermore, linear regression analysis for the parameters affecting lipocalin level in our study, showed that BMI was the only significant confounder affecting lipocalin level. So, the reduction in lipocalin level following metformin therapy in PCOS group in our study may be due to weight reduction perse. Conclusion PCOS per se is not associated with elevated serum lipocalin-2 levels. Metformin therapy induces a significant reduction in serum lipocalin-2 levels, weight, BMI, waist circumference and HOMA-IR in patients with PCOS. Reduction of BMI was the only significant confounder affecting lipocalin level after metformin therapy. So the reduction in lipocalin level following metformin therapy in patients with PCOS in our study may be due to weight reduction perse.