PARENT SESSION
OVARY - C

Wednesday, August 4, 2004
10:30 AM–12:30 PM
Buchanan Courtyard

(770) VANISHING INTRAVASCULAR OOCYTES IN AGING HUMAN OVARIES.

Svetlikova, Marta¹, Caudle, Michael^{1, 2}, Upadhyaya, Nirmala², Bukovsky, Antonin^{1, 2}, ¹ Laboratory of Development, Differentiation and Cancer, Knoxville, TN² Department of Obstetrics and Gynecology, Knoxville, TN

ABSTRACT- Former studies have shown that the number of primary follicles in human ovaries decreases significantly from the 40 years of age. Recently, we observed that ovaries of younger women show formation of new primary follicles from epithelial nests assembling with oocytes in the ovarian cortex. This was accompanied by an accumulation of ZP+ oocytes or their remnants in occasional ovarian medullary vessels, suggesting that there might be an excess of nascent oocytes. This study was conducted to investigate if similar ZP+ oocytes or ZP+ material occur in aging ovaries. We attempted to answer a question if the significant decline of primary follicle numbers in women entering the fourth decade of life is associated with the lack of formation of new oocytes or if new primary follicles fail to be formed in spite of the availability of nascent oocytes. We investigated cytokeratin (CK), zona pellucida (ZP), and endothelial cell markers by single, double and triple color immunohistochemistry in ovaries of 17 premenopausal (mean age 44.8 + 3.5 SD, range 40-50 years; 33 biopsy samples) and 10 postmenopausal women (mean age 55.8 + 7.2 SD, range 51-75 years; 17 biopsy samples), and compared the data with younger females (mean age 32.8 + 4.1 SD, range 27-38 years; 41 biopsy samples). Four of the twelve younger females (33%) showed ZP+ oocytes or ZP+ material in occasional medullary vessels, either in one or both ovaries. In contrast, no ZP immunoreactivity was detected in ovarian vessels of premenopausal and postmenopausal women. These data indicate that formation of new oocytes is a relatively frequent event in ovaries of younger women. We propose that during the optimum reproductive period, waves of atresia affect groups of older follicles, and this is followed by waves of formation of new follicle cohorts. From 40 years of age, the remaining pool of follicles may persist without replacement. This is associated with a significant decline of follicular pool in aging human females.

KEY WORDS: ovary, human, ovarian follicle, regeneration