Assessing Male Gamete Genome Integrity to Ameliorate Poor ART Clinical Outcome.

Overview

abstract

OBJECTIVE: To assess the role of evaluating Sperm Chromatin Fragmentation (SCF) as a tool to guide treatment in couples who achieved unexpectedly poor clinical outcomes following ICSI. DESIGN: We identified couples with an unexpectedly suboptimal clinical outcome following Intracytoplasmic Sperm Injection (ICSI), who were then screened for SCF. Consequently, the same couples were counselled to undergo a subsequent ICSI cycle using either ejaculates processed by Microfluidic Sperm Selection (MFSS) or spermatozoa retrieved from the testis, and clinical outcomes were compared. To confirm the sole effect of a compromised male gamete, we compared ICSI outcome in cycles where male gametes with abnormal SCF were used to inseminate autologous and donor oocytes. Finally, to eliminate an eventual confounding female factor component, we compared clinical outcome of ICSI cycles utilizing sibling donor oocytes injected with spermatozoa with normal or abnormal SCF. SETTING: Academic Reproductive Medicine Center point of care. PATIENT(S): The patient population consisted of a total of 76 couples with reproductively healthy and relatively young female partners, and male partners with compromised semen parameters, but suitable for ICSI. In a sub analysis, we identified 67 couples with an abnormal SCF who underwent ICSI cycle(s) with donor oocytes. Furthermore, we identified 29 couples, 12 with normal SCF and 17 with abnormal uncorrected SCF, and 7 couples with corrected abnormal SCF spermatozoa verses a control, who used sibling donor oocytes for their ICSI cycle(s). INTERVENTIONS: For couples who resulted in surprisingly low clinical outcomes following ICSI, despite semen parameters adequate for ICSI and a normal female infertility evaluation, a SCF assessment was performed on the semen specimen utilizing the TUNEL assay. The couples then underwent a subsequent ICSI cycle with spermatozoa processed by MFSS or surgically retrieved. Moreover, cycles utilizing donor oocytes were used to confirm the sole contribution of the male gamete. MAIN OUTCOME MEASURE(S): Clinical outcome such as fertilization, embryo implantation, clinical pregnancy, delivery, and pregnancy loss rates were compared between history and treatment cycle(s) using ejaculated spermatozoa selected by MFSS or from a testicular biopsy, taking into consideration level of SCF. In a sub-analysis, we reported the clinical outcome of 67 patients who used donor oocytes and compared to cycles where their own oocytes were used. Furthermore, we compared ICSI clinical outcomes between cycles using sibling donor oocytes injected with low versus high SCF without or with sperm intervention aimed at correcting the final SCF. RESULT: (s): In a total of 168 cycles, 76 couples had in a prior cycle with a 67.1% fertilization, ana a clinical pregnancy and pregnancy loss rate of 16.6% and 52.3%, respectively. Following testing for SCF, DNA fragmentation rate was 21.6%. This led to a subsequent ICSI cycle with MFSS or TESE, resulting in a clinical pregnancy of 39.2% (P<0.01), and delivery of 37.3% (P<0.001). The embryo implantation rose to 23.5% (P<0.001). while the pregnancy loss decreased to 5% in the treatment cycle (P<0.01). This was particularly significant in the moderate SCF group, reaching an embryo implantation of 24.3% (P<0.001), clinical pregnancy of 40.4% (P<0.01), and a delivery rate of 36.2% (P<0.001) reducing the pregnancy loss to 10.5% in post sperm treatment cycles (P<0.01). In 67 patients with high SCF who utilized donor oocytes a significantly higher fertilization of 78.1% (P<0.00001) and embryo implantation of 29.1% (P<0.0001) was reported, as compared to couples also with an elevated SCF who utilized their own. Interestingly, the clinical pregnancy and delivery rates only increased slightly from 28.0% to 36.1% and from 23.7% to 29.2%, respectively. To further control for a female factor, we observed couples that shared sibling donor oocytes, 17 with a normal SCF and 12 with an abnormal (uncorrected) SCF. Interestingly, the abnormal SCF group had an impaired fertilization (69.3%, P<0.001), embryo implantation (15.0%, P<0.05), and delivery (15.4%, P<0.05) rate. For an additional 15 couples who split their donor oocytes, 8 couples had a normal SCF, and while 7 couples originally had abnormal SCF, 4 used microfluidic processing, 2 used testicular spermatozoa and 1 used donor spermatozoa, resulting in comparable clinical outcomes to the normal SCF group. CONCLUSION: A superimposed male factor component may explain the disappointing ICSI outcome in some couples despite reproductively healthy female partners. Therefore, it may be useful to screen couples for SCF to guide treatment options and maximize chances of a successful pregnancy. The improved but suboptimal pregnancy and delivery outcomes observed in couples using donor oocytes confirmed the exclusive detrimental role that the male gamete exerted on embryo development despite the presence of putative oocyte repair mechanisms.