Elevated peritoneal soluble endoglin and GDF-15 in infertile women with severe endometriosis and pelvic adhesion

Chronic inflammation and pelvic adhesion play a critical role in endometriosis-related infertility. Research studies suggest that TGF-β superfamily members, such as soluble endoglin (sEng), growth differentiation factor 15 (GDF-15) and tumor growth factor-beta (TGF-β1) contribute to the regulation of inflammation, angiogenesis and cell adhesion. The objective of this study is to investigate the association between the concentrations of these TGF-β-related members and the clinical parameters of infertile women with endometriosis.

Sixty-five infertile women who underwent laparoscopy were divided into two groups in this study: those who had endometriosis (n = 33) and control subjects with benign gynecologic disorders (n = 32). The levels of TGF-β- related members in peritoneal fluid and serum were evaluated by the enzyme-linked immunosorbent assay (ELISA). Clinical and hematological parameters were documented and analyzed.

Endometriosis cases had significantly higher levels of sEng, GDF-15 and TGF-β1 in peritoneal fluid (p<0.0005) compared to control subjects, but not in serum. Moreover, serum GDF-15 level was significantly elevated in the late-stage endometriosis compared to the early-stage group. The levels of three TGF-β related molecules in peritoneal fluid showed positive correlations with rASRM score. Blood neutrophil counts have correlation with the peritoneal sEng concentration.

Our novel evidence on the elevated concentration of peritoneal sEng and GDF-15 in endometriosis, specifically in the late-stage, may indicate the essential role of TGF-β-dependent signaling in endometriosis. Serum GDF-15 might serve as a candidate biomarker for endometriosis severity. Further studies are warranted to investigate the role and regulation of these molecules in endometriosis.