P-112 Utilizing surgical sperm retrieval to improve clinical outcomes for men with high sperm chromatin fragmentation in their ejaculates

Abstract

Abstract Study question In men with elevated sperm chromatin fragmentation (SCF), can surgical sperm retrieval from the proximal area of the male genital tract improve clinical outcomes? Summary answer Spermatozoa retrieved from the epididymis or testes demonstrate higher genomic integrity and are associated with enhanced embryo implantation, clinical pregnancy, and delivery rates. What is known already Sperm genomic integrity is a key factor in achieving a successful pregnancy. During spermiogenesis, alteration of DNA topology involving nuclease and ligase mechanisms is required for supercoiling and DNA compaction. If a proper DNA repair mechanism fails during this intricate process, spermatozoa with DNA fragmentation should be picked up by the epididymis and phagocytized. When this mechanism fails, along with the presence of superimposed reactive oxygen species in the male genital tract, spermatozoa with DNA fragmentation may reach the ejaculates. We have previously demonstrated that retrieving spermatozoa directly from the epididymis and testes yields gametes with higher conserved genomic integrity. Study design, size, duration In a nine-year timespan, we identified over 1,000 men with high SCF in their ejaculates; 144 patients consented to undergo surgical retrieval of spermatozoa. In a preliminary assessment, their clinical outcomes were compared to those from men with normal SCF (n = 539). Of these men, 53 consented to undergo subsequent ICSI cycles with their female partners using surgically retrieved spermatozoa from the epididymis (n = 15) or testes (n = 38). Fertilization and clinical outcomes were compared. Participants/materials, setting, methods Ejaculated, epididymal, and testicular specimens were screened by terminal deoxynucleotidyl dUTP nick-end labeling (TUNEL) to assess SCF using a commercially available kit. A total of 500 spermatozoa/sample were screened with a normal threshold of 15%. Surgical samples from the epididymis and testes were cryopreserved in multiple vials for subsequent ICSI cycles. Main results and the role of chance In the preliminary assessment, ICSI outcomes utilizing ejaculated spermatozoa were compared between men with normal (n = 539, 9.3±3%) and abnormal (n = 144, 28.2±13%) SCF. Although fertilization did not differ, implantation (24.1% vs. 7.8%) and clinical pregnancy rates (CPR, 35.8% vs. 14.6%) were significantly impaired (P < 0.001) in men with elevated SCF. SCF assessment on surgically retrieved spermatozoa revealed a decreasing trend from 28.2±13% in the ejaculate to 16.6±9.2% in the epididymis and 10.1±5.7% in the testes. A total of 53 men underwent 79 subsequent ICSI cycles using surgically retrieved spermatozoa. Compared to their historical cycles using ejaculates (n = 65), ICSI with surgically retrieved sperm substantially improved implantation (18.8% vs. 2.1%; P < 0.001), CPR (36.5% vs. 5.3%; P < 0.0001), and ongoing/delivery rates (33.8% vs. 4.1%; P < 0.0001). Among these couples, 15 underwent 21 ICSI cycles utilizing epididymal spermatozoa with a mean SCF of 16.6±9%. Implantation (26.5% vs. 3.7%; P < 0.05), CPR (68.4% vs. 4.2%; P < 0.0001), and ongoing/delivery rates (57.1% vs. 4.2%; P < 0.0001) were significantly improved compared to the historical cycles. The remaining 38 patients underwent ICSI with testicular spermatozoa with an average SCF of 10.1±6%. Implantation (15.0% vs. 2.6%; P < 0.01), CPR (25.5% vs. 6.1%; P < 0.01), and ongoing/delivery rates (23.6% vs. 3.0%; P < 0.05) were higher when compared to historical cycles. Limitations, reasons for caution Although surgically retrieved spermatozoa can be used to enhance clinical outcomes in couples with high SCF, epididymal spermatozoa yielded higher pregnancy rates despite the higher level of SCF in these specimens compared to testicular spermatozoa. This can be explained by the corrective action of the ICSI procedure itself. Wider implications of the findings Our study demonstrated that sperm DNA integrity progressively increases through the journey of the male genital tract. In couples with a compromised sperm genome, surgically retrieved spermatozoa can be beneficial. Therefore, assessing SCF might be used a routine tool to evaluate the male gamete. Trial registration number N/A