Effects of a hyperandrogenaemic state on the proliferation and decidualization potential in human endometrial stromal cells.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women, involving hyperandrogenaemia and insulin resistance. Treatment options include dexamethasone, as well as the off-label use of metformin. To evaluate the impact of those drugs on cyclic changes in endometrial development, we tested possible effects of metformin and dexamethasone on endometrial stromal cells decidualisation, proliferation, and gene regulation in a hyperandrogenaemic microenvironment in vitro. METHODS/DESIGN: Ten endometrial biopsies (of which five were decidualized in vitro) were used from regularly cycling women. Cells were treated with testosterone, dexamethasone, and metformin in different concentrations. Thereafter, cells were assessed for proliferation and decidualization capacity, as well as mTor and MMP-2 gene regulation. RESULTS: Metformin showed a dose-dependent negative effect on prolactin secretion, a known decidualization marker. This effect was stronger in a hyperandrogenaemic condition and could not be compensated by dexamethasone. Testosterone had a dose dependent negative effect on proliferation in decidualized endometrial stromal cells. Dexamethasone slightly compensated the negative proliferative effect only in low-dose testosterone. High-dose metformin also showed a dose-dependent reduction in endometrial stromal cell proliferation without a major impact by testosterone or dexamethasone in decidualized and non-decidualized cells. High-dose metformin significantly reduced the expression of matrix metalloproteinase-2 (MMP-2) and mechanistic Target of Rapamycin (mTor), regardless of the concentration of dexamethasone and testosterone. The strongest effect could be observed for the combination with high-dose dexamethasone. CONCLUSION: When therapies, such as metformin and dexamethasone, are used to normalize peripheral androgen levels in patients with PCOS, their effect on the endometrial microenvironment should be taken into consideration as well, especially metformin has to be used with caution because of its dose dependent, possibly inhibiting effect at the endometrial proliferation.

Modulation of the IGF system and proliferation in human endometrial stromal cells by metformin: a dose-dependent effect.

PURPOSE: To assess the metformin effect on endometrial stromal cell decidualization, proliferation, gene and protein expression of IGFBPs, IGFs and their receptors. METHODS: Human endometrial stromal cells (hESCs) were cultured from endometrial biopsies of 11 women undergoing surgery for benign reasons. hESCs were decidualized with and without metformin in increasing doses. Supernatant and cells were harvested after decidualization for 12-14 days, followed by real-time PCR of IGFBP 1-6, IGF I, IGF II and their receptors. Prolactin, and IGFBP-1, -3, and -6 were additionally analyzed in supernatant by ELISA. Proliferation of hESCs and decidualization of hESCs were assessed under the influence of metformin. Data were analyzed using the paired t test with p < 0.05 considered significant. RESULTS: While lower concentrations of metformin (10(-4), 10(-5 )M) did not influence the decidualization and proliferation capacity of hESCs, higher concentrations (10(-3), 10(-2 )M metformin) significantly (p < 0.05) diminished decidualization, as well as stromal cell proliferation in a dose-dependent manner. Higher concentrations of metformin lead to a significant (p < 0.05) dose-dependent attenuation of the progesterone effect with regard to IGFBP-1, -3, -5, -6, as well as IGF I receptor, while it did not change the expression of IGFBP-2 and -4, IGF I and II and the IGF II receptor. This was confirmed on the protein level for IGFBP-1, -3, and -6. CONCLUSION: We were able to demonstrate for the first time a dose-dependent local effect of metformin within hESCs. Metformin might therefore influence locally the endometrial proliferation and maturation, and could open up new treatment options for gynecological diseases by vaginal application of metformin.