Follistatin is induced by IL-1ß and TNF-α in stromal cells from endometrioma.

The aim of this study is to examine the regulation of follistatin, an activin-binding protein, in endometriosis. Endometrioma stromal cells (EoSCs) were obtained from 9 patients undergoing laparoscopy of the ovarian endometrioma. In cultured EoSCs, interleukin 1ß (IL-1ß) and tumor necrosis factor-α (TNF-α), which could induce activin-A, also induced follistatin messenger RNA (mRNA) and protein. The cystic fluid of endometrioma from 8 patients was obtained to measure the concentration of activin-A and follistatin by enzyme-linked immunosorbent assay (ELISA). Also, activin activity in the fluid was examined by erythroid differentiation assay using mouse erythroleukemia F5-5.fl cells. In the cystic fluid of endometrioma, the mean values of activin-A and follistatin concentration were 36.8 ng/mL and 4.0 ng/mL, respectively. In a bioassay, all 8 samples exhibited activin activity, which was equivalent to recombinant activin-A activity of 12.8 ± 1.4 ng/mL. Although follistatin was present in the cystic fluid of endometrioma, the activity of activin, which is an exacerbation factor of endometriosis, was predominant in vivo.