Identification and treatment of men with phospholipase Cζ–defective spermatozoa

Abstract

Objective: To identify and treat the gamete responsible for complete fertilization failure with intracytoplasmic sperm injection (ICSI) using a newly proposed assisted gamete treatment (AGT). Design: Prospective cohort study. Setting: Center for reproductive medicine. Patient(s): One-hundred and fourteen couples with an adequate number of spermatozoa for ICSI and a fertilization rate of %10%, after controlling for maternal age. Intervention(s): Couples with an oocyte-related oocyte activation deficiency (OAD) underwent a subsequent cycle with a modified superovulation protocol; couples with sperm-related OAD had an additional genetic and epigenetic assessment to identify mutations and expression levels of the corresponding genes. Main Outcome Measure(s): Treatment cycle outcome for couples undergoing ICSI with either a modified superovulation protocol or AGT compared with their historical cycle. Result(s): A total of 114 couples matched the inclusion criteria, representing approximately 1.3% of the total ICSI cycles performed at our center, with age-matched controls. Fifty-two couples were confirmed negative for sperm-related OAD by the phospholipase Cz (PLCz) assay, indicating oocyte-related factors in their failed fertilization cycles. Couples were treated by one of two AGT protocols, AGT-initial or AGT-revised, in a subsequent attempt that was compared with their historical cycle. Subsequent ICSI cycles with a tailored superovulation protocol yielded significantly higher fertilization (59.0% vs. 2.1%) and clinical pregnancy (28.6% vs. 0) rates. In 24 couples (mean AE standard deviation: maternal age, 35.6 AE 5 years; paternal age, 39.8 AE 6 years) sperm-related OAD was confirmed; in four men, a deletion on the PLCZ1 gene was identified. Additional mutations were also identified of genes supporting spermiogenesis and embryo development (PIWIL1, BSX, NLRP5) and gene deletions confirming a complete absence of the subacrosomal perinuclear theca (PICK1, SPATA16, DPY19L). Subsequent AGT treatment provided higher fertilization (42.1%) and clinical pregnancy (36% vs. 0%) rates for couples with a history of impaired (9.1%) fertilization. A comparison of the two AGT protocols, AGT-initial or AGT-revised, revealed that the latter yielded even more favorable fertilization (37.6% vs. 45.9%) and clinical pregnancy (21.1% vs. 83.3%) rates. Conclusion(s):In couples with an oocyte-related OAD, tailoring the superovulation protocol resulted in successful fertilization, term pregnancies, and deliveries. In couples with a sperm-related OAD as determined by PLCz assay, mouse oocyte activation test, and the assessment of gene mutations and function, AGT was successful. The AGT-revised protocol yielded an even higher fertilization rate than the AGT-initial protocol, resulting in the birth of healthy offspring in all couples who achieved a clinical pregnancy. (Fertil Steril Ò 2020;114:535-44. Ó2020 by American Society for Reproductive Medicine.) El resumen está disponible en Español al final del artículo.

Single-center thorough evaluation and targeted treatment of globozoospermic men

“…Couples with a normal OASCF who were continuing treatment at our center ( n = 4) underwent conventional ICSI, while consenting couples with an OASCF deficiency ( n = 7) were treated by ICSI with AGT in their subsequent cycles (Fig. 1 ) [ 20 ].

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“…The use of oocyte activation with ICSI has been shown to achieve fertilization and successful pregnancies, even in patients with the most severe cases of globozoospermia [ 5 ]. However, its application has recently been shown to be necessary only in cases with a confirmed sperm-related, oocyte-activating deficiency [ 20 ].…”

“…According to test results, couples were categorized by the degree of globozoospermia and treated according to OASCF content. Only couples with absent OASCF were treated by ICSI with assisted gamete treatment (AGT), where both the spermatozoa and oocytes were exposed to calcium ionophore [ 20 ]. Clinical outcomes were compared between the two globozoospermia forms and their respective treatment protocols.…”

Diagnosis and Treatment of Male Infertility-Related Fertilization Failure

“…Up to now, the predictive potential of PLCζ immunostaining and immunoblotting was questionable. However, two very recent articles have proposed new algorithms using PLCζ immunostaining assay for the clinical management of patients suffering from FF after ICSI, which appear to be very useful to determine the responsible gamete and to predict the efficacy of AOA in the next treatment [51,148].…”

Reproductive Outcomes of Artificial Oocyte Activation after ICSI Undergoing Blastocyst Transfer: A 6-year Retrospective Cohort Study

“…The leading cause for TFF after ICSI has been attributed to oocyte activation de ciencies (OADs), which can be related to sperm or oocyte factors. Studies have shown that AOA can be helpful to couples who have clear sperm-related OAD [2,4,6].…”