Differing endometrial expression of calcium modulating transient receptor potential channels

To the editor

Assisted reproductive techniques (ART) have increased the live birth success rate, but there is still a significant implantation failure rate. Epithelial cell calcium homeostasis is tightly regulated by mechanisms that include activation of the TRP channel superfamily of 9 families including TRPC (Canonical) [1]. TRPCs are located on the cell membrane and act as receptor-operated channels (ROC), whilst cytosolic localization of these channels indicates their role as store-operated channels (SOC): both ROCs and SOCs are key players in the regulation of intracellular calcium homeostasis [2]. TRPC 1–4 and 6 expression in the bovine reproductive tract has been reported; these receptors exhibit hormone modulation [2] and calcium dysregulation can lead to menstrual disturbances [3], suggesting that TRPC receptors may modulate calcium in the human endometrium and affect implantation and fertility.

Endometrial samples at day 21 of the menstrual cycle (MC) from 15 patients (Table 1) prior to ART were taken; five women with normal female investigation, but with male factor infertility (MFI), acted as controls; five women had unexplained infertility (UI) and five had PCOS with no MFI. All patients in the UI and MFI groups had regular ovulatory menstrual cycles (a 28-day cycle ± 1-day), with no intermenstrual or postcoital bleeding or dysmenorrhoea. The diagnosis of PCOS was based on all three diagnostic criteria of the Rotterdam consensus [4], but endometrial samples were only taken from those sequential PCOS patients who had ovulated in that cycle as confirmed by the presence of a corpus luteum on ultrasound examination. None of the patients had reported successful pregnancy or miscarriage. All patients gave written consent and study approval was granted by the NHS UK Local Research Ethics.

Other Information

Published in: Journal of Translational Medicine
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1186/s12967-021-02763-z