The in vivo and in vitro effects of kisspeptin on human ovarian function

Lisa Owens; Ali Abbara; Avi Lerner; Shannon O; Georgios Christopoulos; Shirin Khanjani; Rumana Islam; Maneshka Liyanage; Kate Hardy; Stuart Lavery; Aylin Hanyaloglu; Waljit Dhillo; Stephen Franks

doi:10.1530/endoabs.56.OC2.1

Background: Infertility is a common problem and the number of couples receiving assisted reproductive treatment (ART) is increasing. Using GnRH agonists (GnRHa) to trigger oocyte maturation has been shown to reduce risk of ovarian hyperstimulation syndrome (OHSS), a common complication of IVF, compared to the more traditional use of human chorionic gonadotropin (hCG). Kisspeptin has recently been shown to be a safe trigger of oocyte maturation in women at high risk of OHSS. Kisspeptin stimulates gonadotropin secretion indirectly by stimulation of hypothalamic GnRH neurons. Kisspeptin and its receptor are also expressed in the human ovary but direct actions of kisspeptin on the ovary are unknown.

Objectives: 1. To compare effects of the maturation triggers hCG, GnRHa and kisspeptin on expression, in granulosa lutein (GL) cells, of genes involved in ovarian reproductive function and steroidogenesis and 2. To examine in vitro effects of kisspeptin treatment on ovarian steroidogenesis in GL cells. 3. To treat GL cells in vitro with Kisspeptin-10 and kisspeptin-54 and to measure activation of kisspeptin receptor through calcium signal generation and protein expression of phospho-ERK and phospho-AKT.

Materials & methods: GL cells were isolated from follicular fluid collected at the time of oocyte retrieval. RNA was extracted from the cells and RT-qPCR completed comparing expression of ovarian steroidogenesis and gonadotropin receptor genes. GL cells were cultured and treated with hCG or kisspeptin and gene expression was analysed. GL cells were treated with kisspeptin-54 and kisspeptin-10 at varying dosages and timepoints.

Results: GL cells from women who received kisspeptin trigger in vivo showed significantly higher expression, compared to other triggers, of FSH receptor, LH/CG receptor, steroid acute regulatory protein, 3-beta-hydroxysteroid dehydrogenase type 2, aromatase, inhibins A and B, oestrogen receptors α and β. Gene expression of kisspeptin receptor was unchanged. Whereas GL cells treated in vitro with hcG showed the expected increase in steroidogenic gene expression, kisspeptin treatment in vitro had no effects. There was no evidence of activation of kisspeptin receptor after administration of kisspeptin-10 and -54.

Conclusion: Kisspeptin-54, used as an oocyte maturation trigger, augments expression of genes involved in ovarian steroidogenenesis in human granulosa cells, when compared to traditional maturation triggers. However, there was no effect of kisspeptin administration in vitro, indicating that the in vivo effects are likely to be mediated by the action of kisspeptin on gonadotropin secretion rather than by direct effects on the ovary.

Endocrine Abstracts

OC2.1