Distribution and epidermal growth factor receptor expression of primordial follicles in human ovarian tissue before and after cryopreservation

Abstract

The freezing of ovarian tissue and the growth of immature oocytes from primordial follicles is an interesting concept in ovarian tissue transplantation and in-vitro fertilization. In this study, the morphology and distribution of primordial follicles were studied in ovarian tissue from 24 women before and after cryopreservation. Cryopreservation did not significantly change either the morphology or number per unit volume of morphologically normal follicles in frozen ovarian tissue. Primordial follicles were predominant, accounting for 78.6% and 82.6% of total follicles in fresh and frozen ovarian tissues respectively. The distribution of follicles was extremely uneven in ovarian tissue. A large variation in follicle numbers was observed in ovarian tissue samples from patient to patient, and even in the same patient, indicating that the number of follicles counted in one sample of ovarian tissue may not represent the number of follicles in other tissue samples. Ovarian tissue could be frozen in the form of strips instead of fragments for fast processing and better viability of ovarian tissue in cryopreservation. The number of follicles in ovarian tissue declined with the increasing age of the patients. An immunohistochemical study showed that immunoreactivity for the epidermal growth factor (EGF) receptor was detected in primordial follicles of adult ovarian tissue. EGF receptor staining was most intense in the oocytes of primordial follicles. Weak staining for EGF receptor was observed in some surrounding pregranulosa cells. Immunohistochemical staining for EGF receptor was also present in the stromal cells of ovarian tissue, but to a much lesser degree. There was no significant difference in the immunohistochemical staining for EGF receptor in ovarian tissue before and after cryopreservation.

Assessment of Estrogen Receptors and Apoptotic Factors in Cryopreserved Human Ovarian Cortex

“…This is in accordance with previous reports Qu et al 2000] and is probably due to the wide range of age. However these results suggest that follicles are unevenly distributed in the ovarian cortex.…”

A review of 15 years of ovarian tissue bank activities

“…Histological evaluation and follicle count performed on cortical tissue samples prior to cryopreservation is not a reliable method to quantify follicular density due to follicle clustering [23,43,53] and subsequent heterogeneity in analyzed samples [7]. Nevertheless, anatomopathological evaluation remains an essential tool, yielding an initial analysis of the presence of follicles, as well as the presence or absence of malignant cells.…”

Assessment of Ovarian Reserve in Infertile Patients

“…A study assessing the accuracy of basal FSH, estradiol, CCCT, GAST in predicting the total number of follicles, which was determined by histological examination of oopherectomy materials in 22 fertile patients older than 35 years, found a positive correlation between only basal estradiol levels and follicle per unit but not with others 85 . The uneven distribution of follicles in the ovary makes a large variation even in the same ovary 86 . When the random follicular distribution and potential risks of procedure are taken into consideration together, this procedure is not justified on current available data.…”