Immunohistochemical Detection of the Mechano-Gated Piezo Channels in the Normal Endometrium and in Endometriosis

Endometriosis is an inflammatory estrogen-dependent disorder characterized by pain, dyspareunia, dysmenorrhea, and infertility. This is due to the invasion of different organs by endometrial tissue that causes inflammation, angiogenesis, and fibrosis. The ion channels Piezo1 and Piezo2 primarily work as mechanosensors and mechanotransducers but also have functions that could participate in the clinical hallmarks of endometriosis. Thus, we investigated the occurrence and localization of Piezo1 and Piezo2 in healthy human endometrium and in endometriosis using immunohistochemistry. In healthy endometrium, Piezo1 immunoreactivity was detected in the glands and to a lesser extent in the stroma; Piezo2 was present in the same locations but at low or residual levels. In ectopic endometriosis, there was an increase in the intensity of Piezo1 regardless of location; Piezo2 only showed a net increase in the ovarian and vaginal endometriosis foci. The present results demonstrate the occurrence of Piezo ion channels in the healthy human endometrium for the first time, as well as an increase in Piezo1 in ectopic endometriosis, and no changes in Piezo2 with the exception of the ovary and vagina. However, these results are descriptive and qualitative, although they may serve as the basis for further studies. The role of these ion channels in the endometrium and in the pathogenesis of endometriosis remains to be elucidated, and more precise methods are needed to follow up on this pilot study that can be better analyzed statistically to confirm the results.