Apoptosis of vaginal epithelial cells in clinical samples from women with diagnosed bacterial vaginosis

Elena Roselletti,Samuele Sabbatini,Anna Vecchiarelli,Antonella Mencacci,Stefano Perito,Claudia Monari

doi:10.1038/s41598-020-58862-2

Elena Roselletti, Samuele Sabbatini + Show 4 more

Open Access

https://doi.org/10.1038/s41598-020-58862-2

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Journal: Scientific Reports	Publication Date: Feb 6, 2020
Citations: 19	License type: open-access

Affiliation: University of Perugia

Abstract

Bacterial vaginosis (BV) is one of the most common vaginal infections among women of childbearing age. Gardnerella vaginalis (G. vaginalis) is a keystone microorganism present in more than 95% of all BV cases. The first step of the infection process in BV is mediated by interaction of microorganisms with epithelial cells (ECs). However, the role of these cells in BV pathogenesis is largely unknown. The present study aimed to investigate the vaginal EC response during BV. Twenty healthy women and 34 women with BV were enrolled in this study. The number of ECs in the vaginal swab was counted and analyzed for intracellular signals and apoptosis by flow cytometry. Cell damage was evaluated by lactate dehydrogenase assay. Compared to that in healthy donors, the percentage of exfoliated vaginal ECs was increased in women with BV, and an absence of neutrophils was observed in both groups. Activation signals, such as p-IκBα and c-Fos were unmodulated in the vaginal ECs of women with BV. Moreover, EC damage and apoptosis were significantly increased in patients with BV. Apoptosis was related to caspase-3 activation and the presence of G. vaginalis. This study provides the first evidence of a direct involvement of G. vaginalis in the apoptotic process of vaginal ECs during BV. This effect was mediated by caspase-3 activation, and G. vaginalis appeared to be one of causes for inducing EC apoptosis in BV. Hence, our findings suggest a possible explanation for the increased exfoliation of ECs in the vagina during BV.

Highlights

Bacterial vaginosis (BV) is one of the most common vaginal infections among women of childbearing age
The diagnosis of BV is based on the detection of predominant bacterial vaginosis-associated organisms, G. vaginalis, which has the ability to form a dense biofilm adhering to the vaginal epithelium[1]
Vaginal dysbiosis and BV usually occur when Lactobacillus spp., which is the predominant species in the vagina of healthy women, is replaced by various anaerobic bacteria, G. vaginalis

Summary

Introduction

Bacterial vaginosis (BV) is one of the most common vaginal infections among women of childbearing age. Compared to that in healthy donors, the percentage of exfoliated vaginal ECs was increased in women with BV, and an absence of neutrophils was observed in both groups. This study provides the first evidence of a direct involvement of G. vaginalis in the apoptotic process of vaginal ECs during BV This effect was mediated by caspase-3 activation, and G. vaginalis appeared to be one of causes for inducing EC apoptosis in BV. G. vaginalis remains the best-studied species associated with BV, and was, previously, reported by Gardner and Dukes[3] to be the sole etiological agent of BV; the presence of G. vaginalis in healthy women has led to speculation about its virulence potential. The biofilms may ascend to the endometrium, causing pelvic inflammatory disease and risk of adverse pregnancy outcome[6]

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