Evaluation of gamete dysfunction as a cause of failed human in vitro fertilization

[摘要] ENGLISH ABSTRACT:Chapter 1 provides literature based background information on the clinicalimportance of sperm morphology as recorded by strict criteria during thediagnostic approach of the infertile couple. Furthermore, the use of a sequentialdiagnostic schedule for couples in an assisted reproductive programme isemphasized. The author revisited the literature on chromatin packaging ofspermatozoa and addresses this issue as an additional semen parameterproviding information relating to DNA damaged spermatozoa. The chapter alsoincludes evidence underlining the growing need for the implementation of theacrosome reaction as an important contribution to the assisted reproductiveprogramme. Chapter 2 provides detailed descriptions of the material andmethods used during the study. Chapter 3 is sub-divided into 5 sections, each ofwhich represents a separate study that was prepared as a scientific paper. Thestudy included 338 couples consulting for infertility treatment at variousgynaecologists in Pretoria and Johannesburg. The diagnostic assistedreproductive laboratory support was provided by the Andrology laboratory of Drsdu Buisson and partners from Pretoria. In the first study the role of chromatinpackaging as an indicator of in vitro fertilization rates, the semen samples from72 men were used to record their chromatin packaging quality as well as theirsperm morphology classification. Significant different percentages CMA3staining(mean±SE) were recorded among the 2 morphology groups, namely 65.9%±3.5and 44.5%±1.7 (p=0.001). Using cut off values for chromatin packagingestablished during the first study, the second study utilized semen from 140 men in the in vitro fertilization (IVF) and intracytoplasmic sperm injection programme(ICSI) to analyze for sperm concentration, motility, morphology and chromatinpackaging (CMA3).IVF and ICSI data were stratified using 3 basic cut off valuesfor CMA3staining, namely <44%, >44-60% and >60%. The study concluded thatresults on the chromatin packaging quality of spermatozoa could be used as anadditional parameter of sperm quality since it could provide valuable informationon decondensation status of a given sperm population. The third study aimed toestablish zona pellucida induced acrosome reaction response (ZIAR) among 35couples with normal and G-pattern sperm morphology and repeated poorfertilization results during assisted reproduction treatment. Interactive dotdiagrams, divided patients into 2 groups i.e. ZIAR<15% and ZIAR>15% withmean fertilization rates of 49% and 79%, respectively. The study concluded thatthe ZIAR test has diagnostic potential, since it can assist the clinician to identifycouples that will benefit from ICSI therapy. The forth study revisited theimportance of micro-assay for acrosome reaction determinations in a diagnosticandrology laboratory. The micro-assay not only allows the use of a single zonapellucida, but also facilitates the future possibility of using recombinant zonapellucida proteins in a diagnostic test system. The final study in Chapter 3includes results obtained from 49 couples (172 oocytes) and aimed to evaluatethe role of chromatin packaging and sperm morphology during sperm-zonabinding, sperm decondensation and the presence of polar bodies among 170oocytes that failed in vitro fertilization (IVF). Odds ratio analyses indicated thatbeing in the a group with elevated CMA3 staining i.e. >60%, the risk of decondensation failure increases 15.6 fold relative to normal CMA3 staining<44%. Chapter 4 underlines the validity of the sequential diagnostic approachand summarizes the results and value of a multistep diagnostic scheme. Thechapter concludes with the recommendation that both chromatin packagingquality and zona pellucida mediation of the acrosome reaction should be part ofthe diagnostic tools in the assisted reproductive programme.

[发布机构] Stellenbosch University