Award details

Molecular and metabolic markers of oocyte quality

Reference	BB/C007395/1
Principal Investigator / Supervisor	Professor Helen Picton
Co-Investigators / Co-Supervisors	Professor Bruce Campbell, Professor Henry Leese
Institution	University of Leeds
Department	School of Medicine
Funding type	Research
Value (£)	440,372
Status	Completed
Type	Research Grant
Start date	10/06/2005
End date	09/06/2008
Duration	36 months

Abstract

In vitro fertilisation (IVF) and assisted reproduction technologies (ART) are routinely used to treat infertility in humans and to exploit cattle of high genetic merit. However, the technology remains relatively inefficient and costly. One of the main reasons for the low success rates is poor oocyte quality, as we know very little about the factors that confer developmental competence on these cells. Furthermore, our understanding of human oocyte biology has been severely hindered by the limited availability of oocytes for study, the heterogeneity between oocytes and the lack of non-invasive methods to identify developmentally competent oocytes prior to fertilisation. An increased insight into the physiology, genetics, metabolomics and functional genomics of oocytes will enable us to design interventions and treatment regimes aimed at maximising egg quality and increasing the safety and efficiency of assisted conception. The aim of this project is therefore to use methods which are sensitive at the single cell level to identify molecular and metabolic markers of oocyte developmental potential and to characterise their expression profiles during the terminal stages of gonadotrophin-stimulated folliculogenesis in vivo and during oocyte maturation in vitro. The project will utilise bovine and human oocytes matured in vitro and in vivo under different gonadotrophin stimulation regimes to establish whether the amino acid turnover and or mitochondrial activity of individual oocytes can be linked to their competence to undergo fertilisation and develop to the blastocyst stage in vitro. Specifically the project aims to: (1) non-invasively quantify amino acid turnover and mitochondrial activity in individual bovine and human oocytes; (2) identify novel genes which define oocyte maturity and regulate human oocyte developmental competence; and (3) measure the impact of controlled ovarian stimulation on these metabolic parameters and gene expression profiles. Amino acid turnover by individual oocytes and embryos will be quantified by high performance liquid chromatography. Mitochondrial activity and localisation will be measured by ratiometric fluorescent microscopy combined with photon technology. Following metabolic profiling, human oocytes will either be fully karyotyped using multiparameter fluorescent in situ hybridisation, to establish their genetic health or they will be used to create SMART amplified cDNA libraries for molecular screening by microarray. The molecular signature of metaphase II oocytes will be related to their mitochondrial function and metabolic capacity. Finally, the physiological relevance of these determinations will be verified using bovine metaphase II oocytes matured in vivo and harvested from follicles stimulated to develop under defined ovarian stimulation regimes which have been designed to generate difference in oocyte quality. The results generated by this research will increase our understanding of fundamental oocyte biology, it will help redefine clinical ovarian stimulation protocols and will generate oocyte-specific diagnostic and pharmacological targets for clinical and commercial exploitation.

Summary

unavailable

Committee	Closed Committee - Animal Sciences (AS)
Research Topics	Animal Health
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

I accept the terms and conditions of use (opens in new window)

export PDF file

back to list new search