Comparing Seminal Plasma Biomarkers between Normospermic and Azoospermic Men

INTRODUCTION: Azoospermia affects more than 10% - 15% of infertile male subjects attending infertilty clinics. At present, testicular biopsy is the golden standard procedure for evaluating spermatogenesis status in men with azoospermia. Semen collection and analysis is a non-invasive method and has proven to be valuable in the evaluation of spermatogenesis. Identification of seminal plasma markers with testicular or extra-testicular origins have a great value in predicting the prescence of sperm in testicular tissue and presumptive cause of azoospermia. The aim of this study was to find such markers by comparing the content of seminal plasma using different methods in normospermic and azoospermic men. MATERIALS AND METHODS: Semen samples were collected from 200 men attending Avicenna Infertility Clinic (AIC) in Tehran, Iran. Semen samples were analysed according to WHO guidlines. The subjects were divided into two groups: normospermic (n = 100; group one) and azoospermic men (n = 100; group two) according to semen analysis results. Seminal plasma was separated by high speed centrifuagation and stored in -20° C. Four markers including fructose, neutral alpha glucosidase (NαG), inhibin B and anti-Müllerian hormone (AMH) were measured in seminal plasma. Fructose and NαG were evaluated by spectrophotometry, while inhibin B and AMH were assessed by ELISA method. The spermatogenesis status in the azoospermic group was evaluated by histopathological method following testicular biopsy. RESULTS: Fructose concentration showed no difference between the two groups. However, it was significantly correlated with sperm count (p < 0.01, r = -0.408). Seminal plasma inhibin B (OR: 1.01; 95%: CI: 1.005 - 1.016), AMH (OR: 1.63; 95% CI: 1.17 - 2.28) and NαG, (OR: 1.07; 95% CI: 1.04 - 1.1) levels were higher in normospermic subjects compared to azoospermic men. There were significant differences in inhibin B and AMH concentrations between the two groups based on the presence or absence of mature sperm in testicular biopsies (p < 0.01). Inhibin B concentration was positively correlated with sperm count in the normospermic group, however, NαG concentration correlated with sperm count of normospermic men (p < 0.01, r = 0.345) and the subjects' age in both groups. CONCLUSION: Inhibin B and AMH were correlated with the presence of sperm in testicular tissue samples. According to non-specific changes in inhibin B and AMH concentrations, identification of more specific molecular markers in seminal plasma to definitely evaluate the status of spermatogenesis is recommended.