Hypoxia and immune factors

Endometriosis is an estrogen-dependent gynecological disease that affects 10%-15% women of reproductive age. The presence of endometriotic lesions in peritoneal cavity consequently results in a chronic inflammation state, which is characterized with high levels of proinflammatory cytokines and infiltrated immune cells. Studies have shown that cytokines and immune cells are, unexpectedly, facilitate the progression of endometriosis. On the other hand, it is known that the microenvironment where ectopic endometriotic lesion grows has less oxygen supply as compared to the uterine endometrium. Hypoxia plays important roles in mediating biological processes in cells and participates in many pathophysiological conditions, mainly through the action of hypoxia-inducible factor (HIF). Recent studies show that hypoxia can regulate immune responses to modulate pathological processes of endometriosis. Herein, we summarize current understanding between hypoxia and immune factors in contributing to the progression of endometriosis, and discuss the therapeutic potential of targeting HIF as a strategy for treating endometriosis.