Immunohistochemical and ultrastructural identification of telocytes in the lamina propria of human vaginal mucosa

Irene Rosa; Patrizia Nardini; Bianca Saveria Fioretto; Daniele Guasti; Eloisa Romano; Eleonora Sgambati; Mirca Marini; Mirko Manetti

doi:10.1016/j.acthis.2023.152094

Immunohistochemical and ultrastructural identification of telocytes in the lamina propria of human vaginal mucosa

Acta Histochem. 2023 Oct;125(7):152094. doi: 10.1016/j.acthis.2023.152094. Epub 2023 Sep 25.

Authors

Irene Rosa¹, Patrizia Nardini², Bianca Saveria Fioretto¹, Daniele Guasti², Eloisa Romano³, Eleonora Sgambati⁴, Mirca Marini¹, Mirko Manetti⁵

Affiliations

¹ Section of Anatomy and Histology, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134 Florence, Italy.
² Section of Anatomy and Histology, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134 Florence, Italy; Imaging Platform, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134 Florence, Italy.
³ Section of Internal Medicine, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134 Florence, Italy.
⁴ Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Isernia, Italy.
⁵ Section of Anatomy and Histology, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134 Florence, Italy; Imaging Platform, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134 Florence, Italy. Electronic address: mirko.manetti@unifi.it.

PMID: 37757515
DOI: 10.1016/j.acthis.2023.152094

Abstract

Since their relatively recent discovery, telocytes (TCs) have been described as peculiar cells strategically positioned in the stromal tissue component of multiple organ systems of the mammalian body including female reproductive organs (i.e., ovary, uterine tube, and uterus). Nevertheless, current knowledge of TCs in the vagina is very limited. The present study was therefore undertaken to investigate the existence and characteristics of TCs in the stromal tissue of human vaginal mucosa by means of immunohistochemistry, immunofluorescence confocal microscopy, and transmission electron microscopy. In the vaginal lamina propria, TCs were first identified by CD34 immunohistochemistry that revealed the presence of CD34⁺ stromal cells arranged in networks, especially around blood vessels. Double immunofluorescence confocal microscopy allowed to precisely distinguish the perivascular networks of CD34⁺ stromal cells lacking CD31 immunoreactivity from adjacent CD31⁺ microvessels. All the perivascular networks of TCs/CD34⁺ stromal cells situated in the vaginal lamina propria coexpressed platelet-derived growth factor receptor α, which strengthened their identification as TCs. Instead, vaginal mucosal TCs were immunophenotypically negative for c-kit/CD117. The ultrastructural examination confirmed the presence of TCs, namely stromal cells with characteristic cytoplasmic processes (i.e., telopodes) forming labyrinthine networks around blood vessels and releasing extracellular vesicles. Together, our morphological findings provide the first comprehensive demonstration that TCs reside in the human vaginal lamina propria, thus paving the way for further investigation of their putative functions in vaginal mucosal homeostasis and pathophysiology.

Keywords: CD34(+) stromal cells; Confocal laser scanning microscopy; Female reproductive system; Human vaginal mucosa; Telocytes; Transmission electron microscopy.