Extracellular matrix of the human cyclic corpus luteum.

Extracellular matrix regulates many cellular processes likely to be important for development and regression of corpora lutea. Therefore, we identified the types and components of the extracellular matrix of the human corpus luteum at different stages of the menstrual cycle. Two different types of extracellular matrix were identified by electron microscopy; subendothelial basal laminas and an interstitial matrix located as aggregates at irregular intervals between the non-vascular cells. No basal laminas were associated with luteal cells. At all stages, collagen type IV alpha1 and laminins alpha5, beta2 and gamma1 were localized by immunohistochemistry to subendothelial basal laminas, and collagen type IV alpha1 and laminins alpha2, alpha5, beta1 and beta2 localized in the interstitial matrix. Laminin alpha4 and beta1 chains occurred in the subendothelial basal lamina from mid-luteal stage to regression; at earlier stages, a punctate pattern of staining was observed. Therefore, human luteal subendothelial basal laminas potentially contain laminin 11 during early luteal development and, additionally, laminins 8, 9 and 10 at the mid-luteal phase. Laminin alpha1 and alpha3 chains were not detected in corpora lutea. Versican localized to the connective tissue extremities of the corpus luteum. Thus, during the formation of the human corpus luteum, remodelling of extracellular matrix does not result in basal laminas as present in the adrenal cortex or ovarian follicle. Instead, novel aggregates of interstitial matrix of collagen and laminin are deposited within the luteal parenchyma, and it remains to be seen whether this matrix is important for maintaining the luteal cell phenotype.

Gonadotrophin-releasing hormone-antagonist luteolysis during the preceding mid-luteal phase is a feasible protocol in ovarian hyperstimulation before in vitro fertilization.

BACKGROUND: The aims of this study were to investigate whether a high dose of gonadotrophin-releasing hormone antagonist during the preceding luteal phase yields satisfactory luteolysis and downregulation prior to ovarian hyperstimulation in an in vitro fertilization program. METHODS: The treatment protocol was designed as a prospective pilot study in IVF units at two university hospitals. Fifty-one patients with documented poor or normal response to ovarian stimulation underwent 57 treatment cycles. Treatment consisted of 3 mg gonadotrophin-releasing hormone antagonist (cetrorelix) given during the preceding mid-luteal phase as gonadotrophin-releasing hormone-receptor inhibition before ovarian stimulation with follicle-stimulating hormone. RESULTS: All women experienced menstrual bleeding within 2-3 days after the injection of 3 mg cetrorelix. Follicle hormone stimulation could subsequently commence in all cycles. All but three patients developed growing follicles and underwent oocyte retrieval. Seventy-five percent of started cycles reached transfer of one or two good-quality embryos. CONCLUSIONS: A single high-dose gonadotrophin-releasing hormone antagonist given during the preceding luteal phase presents a new and feasible protocol to initiate controlled ovarian hyperstimulation in an in vitro fertilization program.