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The role of intra-ovarian factors in the regulation of follicular death and survival, and management of ovarian lifespan

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Title The role of intra-ovarian factors in the regulation of follicular death and survival, and management of ovarian lifespan
 
Creator Banerjee, Sayani
 
Subject Cell Biology & Physiology
 
Description Living organisms are characterized by their ability to reproduce. History has witnessed the importance given by human societies to the process of procreation. Nevertheless, the people of yore were not capable of comprehending the intricate processes underlying such an important function and attributed it to divine intervention. While fertility and procreation formed the very basis of the dogmas of early life, failure to conceive was perceived as the ultimate curse. Light was thrown on the science of reproductive processes during the sixteenth century. With time, our knowledge has managed to permeate profoundly to understand the process of reproduction, but infertility continues to remain a major and painful life crisis that provides lifelong scarring with significant psychological, economic, demographic and medical effects. The inability to conceive strikes out at the very base of human identity, rapidly plummeting the couple downhill emotional turmoil; needless to say however, the women are subjected to more emotional damage than their male counterparts. Despite all the breakthroughs in the empowerment of women, a woman is still considered incomplete if she cannot become a mother. In humans, reproduction is much the same as for other mammals where they employ in-vivo fertilization that depends on the integrated action of hormones, the nervous system, and the reproductive system. It involves production and maturation of male and female gametes by the gonads, fertilization of the oocyte by spermatozoa, implantation in the uterus, and beginning of a new life. For the woman this demands regular and reliable ovarian cycles centrally featured by ovarian follicle development leading to ovulation in concert with production of estrogen and progesterone under the chief controlling influence of pulsatile gonadotropin secretion from pituitary. For both sexes, the gonads, ovaries in female and testes in male, serve the gametogenic and key endocrine functions, while the hypothalamo-pituitary unit governs the whole process. Diseases interfering with any of these components adversely affect the ability of a couple to conceive. Infertility can be defined as a failure to become pregnant in a period of 12 months for patients under the age of 35 and failure to conceive in a 6 month period for the over 35 age group. Causes of infertility can be found in about 90% of the cases, but despite extensive investigations, about 10% of couples will never know why they cannot conceive.Male or female infertility each accounts for about 30% to 40% of cases. Other cases are due to a combination of male and female factors or to unknown causes. Over the past several decades, demographic and socioeconomic trends have resulted in an increase in the absolute number of women seeking pregnancy in their late 30’s and early to mid 40’s. Compared to other major organ systems the female reproductive system ages to the point of failure at a relatively young age. Although the average age of menopause is 51, peak efficiency in the female reproductive system occurs in the early 20’s with a steady decline thereafter. There is a gradual loss of fertility as a function of female age with the rate of decline in fertility becoming more dramatic after the age of 35. This decline in fertility occurs in spite of the fact that women generally maintain regular, ovulatory menstrual cycles well into the fifth decade. A significant number of women in the advance age group seek evaluation and treatment for infertility. The general consensus is that the ovarian aging is accompanied not only by remarkable decline in the ovarian follicle pool but also by an increase in low-quality oocytes that are not competent enough for fertilization and further development. There are several lines of evidence documenting that oocyte quality determines its fertilization and subsequent development potential, and abnormalities of the oocyte act as the predominant cause of age-associated infertility. Clinical research over the last three decades almost exclusively concentrated on the ovarian hyperstimulation and in vitro fertilization. A number of recent documents raised suspicion over the classical concept of ‘oocyte aging’. Indirect evidence are there to support the view that the so called ‘aged oocytes’ collected from ‘aged ovary’ may be rendered fertile if cultured in ‘suitable’ conditions. This forms the basis of the present dissertation that endeavors understanding the ovarian milieu with respect to size of follicular reserve that, in fact, differentiates the ‘healthy’ and ‘aged’ ovary. The objective is to identify the missing link between declining follicular reserve and loss of oocyte quality, which may perhaps open a new frontier in the management of infertility.
 
Date 2013
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Identifier http://www.eprints.iicb.res.in/2089/1/sayani_thesis.pdf
Banerjee, Sayani (2013) The role of intra-ovarian factors in the regulation of follicular death and survival, and management of ovarian lifespan. PhD thesis, Calcutta University.
 
Relation http://www.eprints.iicb.res.in/2089/