ESPE Abstracts

Background: The fluid milieu along the female reproductive tract has a major role in a complex series of events that follow oocyte ovulation. These include oocyte transport in the fallopian tube, the transport and capacitation of sperm, fertilization, transport of the blastocyst and implantation of the embryo in the uterus. These processes are regulated by the activity of ion channels located on the surface of endometrial epithelia. In our previous studies we showed that epithelial sodium channels (ENaC) are widely distributed in the female reproductive tract (1).

Aim: To examine the expression of ENaC in endometrial biopsy samples obtained by pipelle suction for diagnostic purposes.

Subjects: The samples were obtained from four normal control subjects and a pseudohypoaldosteronism type 1 patient with an Arg508X mutation in the SCNN1A gene that codes for the ENaC alpha subunit (2). The patient failed to conceive naturally and despite nine IVF attempts over six years.

Methods: Endometrial samples were obtained by Pipelle suction. The samples were fixed in formalin and then reacted with anti-ENaC antiserum. After reaction with secondary antibodies sample immunofluorescence were visualized by confocal microscopy. The study was approved by the ethics committee at the E. Wolfson Medical Center.

Results: The analysis showed strong ENaC immunofluorescence along the luminal border (apical membrane) of the epithelial cells in pipelle samples from healthy subjects. In contrast, none of the samples from the PHA patient showed ENaC immunofluorescence. The Arg508X mutation interrupts transport of ENaC subunits to cell surface, yet it would not be expected to disrupt ENaC localization in the cytoplasm. In contrast to endometrium where ENaC is localized in the apical membrane of the epithelial cells, in keratinocytes ENaC is expressed in cytoplasmic pools. Thus, we examined ENaC immunofluorescence in plucked hair follicles from normal subjects and the PHA patient. As expected, ENaC immunofluorescence was detected in the cytoplasm of keratinocytes of both normal and PHA samples.

Conclusion: Our results show that endometrial samples obtained by pipelle biopsy can be used for identification of key proteins by immunofluorescence.

References: 1. Enuka Y, Hanukoglu I, Edelheit O, Vaknine H & Hanukoglu A. Histochem Cell Biol 2012 137 339–353. 2. Hanukoglu A, Edelheit O, Shriki Y, Gizewska M, Dascal N & Hanukoglu I. J Steroid Biochem Mol Biol 2008 111 268–274.