Use of phospholipase C zeta analysis to identify candidates for artificial oocyte activation: a case series of clinical pregnancies and a proposed algorithm for patient management

Abstract

Objective: To investigate the applicability of PLCζ analysis in assisting the clinical decisionmaking process when considering artificial oocyte activation (AOA) for infertile males in assisted reproductive technology (ART). Design:To screen 46 males (43 infertile/13 fertile) using our PLCζ assay.Setting: Fertility unit/university laboratory.Patients: Infertile males with (1) abnormal sperm morphology, (2) total fertilization failure, low fertilization rate (<50%), or repeated fertilization failure in ART. Intervention(s):We analysed PLCζ levels in sperm from fertile and infertile males. Eligible patients subsequently underwent ICSI/AOA with calcimycin (GM508). Main Outcome Measure(s): PLCζ localization, level and the proportion of sperm expressingPLCζ. Thresholds of PLCζ-deficiency, fertilization rates, pregnancy rates and live birth rates of AOA and non-AOA cycles.Results: Compared with 13 controls, 34 of the 43 infertile males had significantly lower levels of PLCζ and/or a significantly lower proportion of sperm exhibiting PLCζ. Of these 34 patients, 15 showed a significant PLCζ reduction in both parameters, which we termed 'PLCζ deficiency'. Five PLCζ-deficient patients opted for AOA; all 5 achieved fertilization and 4 achieved clinical pregnancies and live births. Fertilization rate improved significantly from 18.6% (intracytoplasmic sperm injection, ICSI) to 56.8% (ICSI/AOA) (p<0.001). The clinical pregnancy rate and live birth rate with AOA were both 40% per initiated cycle. Youden index analysis revealed that the cut-offs below which infertile males were likely to benefit from AOA were 71% for the proportion of sperm expressing PLCζ and 15.57 arbitrary units for mean PLCζ level. Conclusion:PLCζ analysis is a useful diagnostic tool to determine patient eligibility for subsequent AOA treatment.

Ionophore application for artificial oocyte activation and its potential effect on morphokinetics: a sibling oocyte study

“…Similarly, no increased rates of congenital birth defects were reported using AOA with calcimycin [47] or ionomycin [48]. The same holds true for the ready-to-use ionophore used in the present study since more than 130 healthy live births have been published [26,27,40,41,49,50]. Although there is growing evidence supporting the clinical relevance of ionophores and their application in IVF laboratories, it must be clarified that AOA should not be considered a routine technique.…”

Calcium Ionophore (A23187) Rescues the Activation of Unfertilized Oocytes After Intracytoplasmic Sperm Injection and Chromosome Analysis of Blastocyst After Activation

“…The widespread application of calcium ionophore (A23187) in AOA can effectively improve the outcome of the patients with sperm abnormalities, fertilization rate, implantation rate, and pregnancy rate (28)(29)(30). However, there are also some reports regarding the activation of discarded oocytes with no signs of fertilization 18-24 h post-ICSI with calcium ionophore (A23187) (31,32).…”

Diagnosis and Treatment of Male Infertility-Related Fertilization Failure

“…However, they are difficult to implement in the IVF labs. In this regard, a combination of genetic screening and immunostaining of PLCζ represents a more simplified and accessible test that will help detecting sperm factors causing male infertility-related FF more rapidly [40,51]. The development of tests that directly investigate the female gamete would also be advantageous, such as genetic screening of female genes related to FF (e.g.,WEE2, PATL2, TUBB8, TLE6) [33,[134][135][136] or the study of the Ca 2+ oscillatory machinery in IVM oocytes from the patient after injection of control sperm [183].…”

“…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].…”

“…Heterologous and homologous ICSI models have been used to diagnose the human sperm activation potential and Ca 2+ oscillatory pattern [48][49][50]. More recently, the evaluation of compromised PLCζ has emerged as a more simplified test that could be more easily introduced in the IVF clinics [40,51]. These diagnostic options allow the clinicians to select the most adequate treatment for the next cycle.…”