Role of interleukin-32 in the pathogenesis of endometriosis: in vitro, human and transgenic mouse data.

ABSTRACT

STUDY QUESTION Does interleukin-32 (IL-32) play a role in the pathogenesis of endometriosis? SUMMARY ANSWER IL-32 might be involved in the pathogenesis of endometriosis through increased viability, proliferation and invasion of endometrial cells. WHAT IS KNOWN ALREADY Endometriosis is characterized as a chronic inflammatory disease and several proinflammatory cytokines are suggested to be involved in its pathogenesis and pathophysiology. IL-32, recognized as a new proinflammatory cytokine and a strong inducer of other proinflammatory cytokines, has been shown to serve as a key modulator in several chronic inflammatory diseases. STUDY DESIGN, SIZE, DURATION This study included comparison of IL-32 levels in the peritoneal fluids between women with and without endometriosis, in-vitro experiments using Ishikawa cells and endometrial stromal cells (ESCs), and experiments on IL-32 transgenic mice and wild-type mice with induced endometriosis. PARTICIPANTS/MATERIALS, SETTING, METHODS: IL-32 levels in the peritoneal fluids were measured using enzyme-linked immunosorbent assays. Cell viability, expression of proliferating cell nuclear antigen (PCNA), and cellular invasiveness were analyzed following in-vitro treatment of Ishikawa cells and ESCs with recombinant IL-32 alpha (α) and gamma (γ). Ectopic endometriotic lesions were compared between IL-32 transgenic mice and wild-type mice after autologous endometrial transplantation with immunohistochemistry for Ki-67 antigen and PCNA. MAIN RESULTS AND THE ROLE OF CHANCE The peritoneal fluid concentration of IL-32 was significantly higher in patients with advanced stage endometriosis compared with the controls. In-vitro treatment with IL-32 α and γ caused significant increases in cellular viability, PCNA expression, and invasiveness in Ishikawa cells and ESCs. The IL-32 transgenic mice had a significantly larger size of the ectopic endometrial lesions with higher expression of Ki-67 antigen and PCNA compared with wild-type mice. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION It is still unclear whether IL-32 is a main regulator, or one of several downstream proinflammatory cytokines, causing establishment and/or progression of endometriosis. WIDER IMPLICATIONS OF THE FINDINGS: Further investigation on IL-32 signaling pathways may contribute to development a more effective treatment of endometriosis. STUDY FUNDING/COMPETING INTEREST(S) This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (Grant number HI16C1682). None of the authors has anything to disclose.