Investigation into the mechanisms of human sperm binding
Research type
Research Study
Full title
Investigation into the mechanisms of human sperm binding and acrosomal reaction when exposed to zona pellucida glycoproteins.
IRAS ID
256274
Contact name
Therishnee Moodley
Contact email
Sponsor organisation
Tayside Medical Science Centre
Duration of Study in the UK
4 years, 11 months, 6 days
Research summary
Although the process of fertilisation in humans is fairly well understood there are still substantial gaps in our knowledge about certain aspects of sperm and oocyte (egg) binding, as well as the cellular functionality that allows this action to occur. Understanding binding and interaction of sperm and oocytes, is particularly relevant in assisted reproductive technology (ART) as this knowledge may promote enhanced sperm screening and selection techniques for improved treatment cycle outcome and shorter time to pregnancy in all patients, but especially older women, women with diminishing ovarian reserve, couples diagnosed with unexplained infertility and couples at risk of failed fertilisation due to issues with oocyte binding.
Low or failed fertilisation in ART is associated with failed treatment cycles and may be attributed to poor semen parameters including severely low concentration, motility and normal morphology (such as in globozoospermia cases), acrosome defects and abnormal chromosomal status.
Prior to sperm fusing with the oocyte membrane, two processes must occur; firstly that the sperm binds to the extracellular coat of the oocyte, the zona pellucida (ZP), and secondly that the sperm must acrosome react. The acrosome is the organelle that lies over the sperm nucleus and the acrosomal reaction involves the acrosomal membrane fusing with the sperm plasma membrane so that the acrosomal contents spill out and facilitate digestion of the oocyte vestments and zona pellucida.
Although it is largely agreed that the acrosomal reaction has to be complete before the sperm penetrates through the zona and binds to the oocyte membrane, there is no consensus on where this reaction occurs or the exact mechanism of binding to ZP glycoproteins (ZP1, ZP2 ZP3 or ZP4). Increased knowledge in this regard, would facilitate the design of screening assays or selection tools for functional sperm to be used in treatment as well as to address the paucity of robust information available in this field. Screening assays and selection tools may enhance IVF treatment outcome and live birth rate and reduce time to pregnancy for most patients.REC name
South Central - Oxford C Research Ethics Committee
REC reference
18/SC/0661
Date of REC Opinion
29 Nov 2018
REC opinion
Further Information Favourable Opinion