Evaluation of immunohistochemical TRPC3 and TRPC6 expression patterns in human endometriosis

Background: Although to date the pathogenesis of endometriosis remains largely unexplained, it is known that processes of migration, proliferation and revascularization and thus calcium as a messenger substance play an important role. Consecutively, the present study examines the immunohistochemical expression of the calcium transient receptor potential channels 3 and 6 (TRPC3 and TRPC6) in ectopically located (outside the uterine cavity) endometrial tissue.

Methods: Laparoscopically collected and histomorphologically verified endometriosis tissues from several different intraabdominal locations were examined (n = 20) and immunohistochemical stainings were performed with anti-TRPC3 and anti-TRPC6 antibodies (Alomone Labs, Jerusalem). Hereby, eutopic endometrium served as a healthy control cohort (n = 6). Staining patterns were evaluated using a modified immunoreactive score (IRS) and exploratory statistical analysis was performed, aiming to determine relations of staining intensities with associated clinical parameters such as rASRM stage and location.

Results: We determined a strong cytoplasmatic TRPC3 and TRPC6 expression in all ectopic endometrial glandular formations, albeit with focally varying staining intensities. Within our cohort, we did not verify a statistically significant difference of TRPC3 and TRPC6 expression between endometriosis patients and a healthy control group or between different clinical affections (rASRM stages).

Conclusions: Our study confirms - to our knowledge for the first time - the successful immunohistochemical assessment of TRPC3 and TRPC6 in endometriosis, setting the basis for future studies aiming at evaluating not only clinical aspects of TRPC3 and TRPC6 expression but also shedding light on its function in the pathophysiological context of endometriosis.