In vitro maturation of human oocytes in a follicle-mimicking three-dimensional coculture

Objective To verify the hypothesis that a three-dimensional, follicle-mimicking structure enhances in vitro maturation yields without hormonal supplementation in an in vitro maturation program. Design Feasibility study; 204 anonymous denuded germinal vesicles retrieved from gonadotropin-treated women were cultured for 48 hours without hormonal supplementation in microdrop culture or in a three-dimensional coculture with granulosa cells in a barium alginate membrane. Setting An assisted reproduction center in Italy. Patient(s) One hundred twenty-two informed women. Intervention(s) Germinal vesicles retrieved after ovarian stimulation were denuded and cultured without hormonal supplementation in microdrop culture or in a three-dimensional coculture with granulosa cells enclosed in the core of a barium alginate capsule. Main Outcome Measure(s) Oocyte maturation and morphological investigation of follicle-mimicking structures. Result(s) Statistically significantly higher oocyte maturation yields were obtained by using the three-dimensional coculture system enclosed in a barium alginate membrane (after 48 hours: coculture, 90.3%; microdrop, 52.0%; odds ratio, 8.51). Morphological investigation indicated that after 48 hours of coculture, the decumulated oocyte appeared to be surrounded by a pseudocumulus structure that lies on the inner surface of the alginate membrane and protrudes toward the capsule’s lumen. Conclusion(s) The maturation yield of cocultured oocytes is eightfold higher than that achieved with a microdrop maturation technique, making a higher number of gametes available for IVF programs. Stereomicroscopic morphological survey indicates a reassembly of granulosa cells surrounding oocyte zona, mimicking an antral cumulus oophorus.