Plasma-free metanephrines, nerve growth factor, and renalase significance in patients with PCOS

Purpose: Polycystic ovarian syndrome (PCOS) is a common heterogeneous condition with probably multifactorial genesis. Animal studies have proven the essential role of the sympathetic nervous system in the syndrome development, while human studies are still contradictory. The present study aims to investigate the possible influence of plasma-free metanephrine (MN), and normetanephrine (NMN), nerve growth factor (NGF), and renalase (RNL) on the hormonal and metabolic parameters in women with PCOS and healthy controls.

Methods: Fifty patients with PCOS and 30 healthy women participated in the study. The plasma-free MN and NMN, NGF, RNL, anti-Mullerian hormone (AMH), gonadotropin, androgen levels, and metabolic parameters were investigated.

Results: Plasma-free NMN and NGF concentrations were increased in PCOS individuals, while RNL levels were decreased compared to healthy volunteers. Increased plasma-free NMN (OR = 1.0213 [95%CI 1.0064-1.0364], p = 0.005) and NGF (OR = 1.0078 [95%CI 1.0001-1.0155], p = 0.046) but not MN or RNL levels were associated with a higher risk of PCOS after adjustment for age. Plasma-free NMN levels were positively associated with the LH (r = +0.253; p = 0.039). androstenedione (r = +0.265; p = 0.029), 17-OH progesterone (r = +0.285; p = 0.024), NGF (r = +0.320; p = 0.008), and AMH (r = +0.417; p < 0.001) concentrations of the investigated women. RNL levels were inversely related to the BMI (r = -0.245; p = 0.029), HOMA-IR (r = -0.250; p = 0.030), free testosterone (r = -0.303; p = 0.006) levels. systolic (r = -0.294; p = 0.008) and diastolic (r = -0.342; p = 0.002) blood pressure.

Conclusions: Increased sympathetic noradrenergic activity and NGF synthesis might be related to the increased AMH and delta-4 androgen levels in a subgroup of PCOS patients. RNL levels might influence the metabolic status of PCOS patients. Further studies are needed to explore the significance of adrenal medullar and autonomic dysfunction for developing different PCOS phenotypes and their subsequent cardiovascular complications.