Rogenhofer N, et al. – The objective of this study was to explore the connection of unexplained recurrent miscarriages with an aberrant sperm protamine mRNA content. The current study showed that both protamine–1 and protamine–2 mRNA levels, as well as the protamine–1 to protamine–2 mRNA ratio in spermatozoa from men whose female partners experienced two or more consecutive miscarriages, were significantly different compared to those from both healthy control men and subfertile couples undergoing IVF/ICSI.

Methods

• Between 2014 and 2016, men whose female partners presented with two or more consecutive unexplained miscarriages in a consultation for recurrent pregnancy loss were selected for this study population.
• At the research laboratory of the Urological Clinic of the University Giessen, spermatozoa from cases and controls were subjected to reverse transcription quantitative PCR (RTqPCR) utilizing specific primer pairs for protamine–1 and protamine–2.
• Protamine–1 and protamine–2 mRNA levels were examined in semen samples from 25 men whose female partners experienced at least two consecutive idiopathic miscarriages before the 20th week of gestation.
• The couples were enlisted amid consultation at the Fertility Center of the LMU Munich, Germany, and at the Clinical Division of Gynecologic Endocrinology and Reproductive Medicine of the Medical University of Vienna, Austria.
• Results were compared with those from 32 healthy donors (WHO, 2010) recruited at the Department of Urology, Pediatric Urology and Andrology, Giessen, Germany, and 107 men whose partners participated in an IVF/ICSI program at the Fertility Center of the LMU Munich, Germany.

Results

• Protamine–1 and protamine–2 mRNA levels as well as the protamine mRNA ratio and all routine semen parameters uncovered major differences between recurrent miscarriage couples and healthy volunteers (P < 0.01).
• When comparing recurrent miscarriage couples with couples undergoing IVF/ICSI, Ct–values of protamine–1 and protamine–2 mRNAs were significantly higher and the protamine mRNA ratio was majorly lower in RM couples (P < 0.01).
• When comparing protamine mRNA levels and the protamine mRNA ratio with routine semen parameters, an important negative correlation was evident between progressive motility and the protamine–2 mRNA level (P = 0.015), and also between non–progressive motility and the protamine mRNA ratio (P = 0.023).