The Developmental Origin of Cervical and Vaginal Epithelium and Their Clinical Consequences: A Systematic Review

Gardnerella vaginalis alters cervicovaginal epithelial cell function through microbe-specific immune responses

BACKGROUND

The cervicovaginal (CV) microbiome is highly associated with vaginal health and disease in both pregnant and nonpregnant individuals. An overabundance of Gardnerella vaginalis (G. vaginalis) in the CV space is commonly associated with adverse reproductive outcomes including bacterial vaginosis (BV), sexually transmitted diseases, and preterm birth, while the presence of Lactobacillus spp. is often associated with reproductive health. While host-microbial interactions are hypothesized to contribute to CV health and disease, the mechanisms by which these interactions regulate CV epithelial function remain largely unknown.

RESULTS

Using an in vitro co-culture model, we assessed the effects of Lactobacillus crispatus (L. crispatus) and G. vaginalis on the CV epithelial barrier, the immune mediators that could be contributing to decreased barrier integrity and the immune signaling pathways regulating the immune response. G. vaginalis, but not L. crispatus, significantly increased epithelial cell death and decreased epithelial barrier integrity in an epithelial cell-specific manner. A G. vaginalis-mediated epithelial immune response including NF-κB activation and proinflammatory cytokine release was initiated partially through TLR2-dependent signaling pathways. Additionally, investigation of the cytokine immune profile in human CV fluid showed distinctive clustering of cytokines by Gardnerella spp. abundance and birth outcome.

CONCLUSIONS

The results of this study show microbe-specific effects on CV epithelial function. Altered epithelial barrier function through cell death and immune-mediated mechanisms by G. vaginalis, but not L. crispatus, indicates that host epithelial cells respond to bacteria-associated signals, resulting in altered epithelial function and ultimately CV disease. Additionally, distinct immune signatures associated with Gardnerella spp. or birth outcome provide further evidence that host-microbial interactions may contribute significantly to the biological mechanisms regulating reproductive outcomes. Video Abstract.

Altered Vaginal Microbiota Composition Correlates With Human Papillomavirus and Mucosal Immune Responses in Women With Symptomatic Cervical Ectopy

Cervical ectopy is a benign condition of the lower genital tract that is frequently detected in women of reproductive age. Although cervical ectopy is regarded as a physiological condition, some women experience symptoms such as leucorrhoea, persistent bleeding and recurrent vaginal infections that require medical intervention. Cervical ectopy has not been linked to cervical cancer, but it is thought to facilitate the acquisition of sexually transmitted diseases (STDs), like Human Papillomavirus (HPV) infection, as it provides a favorable microenvironment for virus infection and dissemination. We and others have described the presence of oncogenic HPV types in women with symptomatic cervical ectopy. The relevance of this finding and the impact of symptomatic cervical ectopy on the cervicovaginal microenvironment (vaginal microbiota, immune and inflammatory responses) are currently unknown. To shed some light into the interplay between HPV, the vaginal microbiota and mucosal immune and inflammatory responses in the context of this condition, we enrolled 156 women with symptomatic cervical ectopy and determined the presence of HPV using a type-specific multiplex genotyping assay. Overall, HPV was detected in 54.48% women, oncogenic HPV types were found in more than 90% of HPV-positive cases. The most prevalent HPV types were HPV16 (29.4%), HPV31 (21.17%) and HPV18 (15.29%). Next, we evaluated the vaginal microbial composition and diversity by 16S rDNA sequencing, and quantified levels of cytokines and chemokines by flow cytometry using bead-based multiplex assays in a sub-cohort of 63 women. IL-21 and CXCL9 were significantly upregulated in HPV-positive women (p=0.0002 and p=0.013, respectively). Women with symptomatic cervical ectopy and HPV infection had increased diversity (p<0.001), and their vaginal microbiota was enriched in bacterial vaginosis-associated anaerobes (Sneathia, Shuttleworthia, Prevotella, and Atopobium) and depleted in Lactobacillus spp. Furthermore, the vaginal microbiota of women with symptomatic cervical ectopy and HPV infection correlated with vaginal inflammation (IL-1β, rho=0.56, p=0.0004) and increased mucosal homeostatic response (IL-22, rho=0.60, p=0.0001). Taken together, our results suggest that HPV infection and dysbiotic vaginal communities could favor a vaginal microenvironment that might delay the recovery of the cervical epithelium in women with symptomatic cervical ectopy and favor STDs acquisition.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

Differences Between Squamous Intraepithelial Lesions of the Vulva and the Cervix

The Lower Anogenital Squamous Terminology project and subsequent publication have grouped preinvasive human papillomavirus-associated squamous intraepithelial lesions of the lower genital tract and adjacent skin as a single entity. We are concerned that as a result of this grouping, some of the clinically relevant differences may not be taken into consideration. We describe differences between high-grade squamous intraepithelial lesion of the vulva and cervix (vulvar intraepithelial neoplasia and cervical intraepithelial neoplasia), in embryology (arising from ectoderm vs mesoderm), clinical presentations (symptoms or signs due to many vulvar lesions vs abnormal cytology), examination techniques and diagnosis (clinical examination of potentially widely involved areas vs colposcopy of the transformation zone), natural history, management, and follow-up requirements (long-term clinical assessment vs cytology and human papillomavirus testing). We believe that failure to understand these important differences will lead to errors in management.

100 years of iodine testing of the cervix: A critical review and implications for the future

OBJECTIVES

We aim to describe the history of iodine testing of the cervix and identify areas where further work is required.

STUDY DESIGN

We conducted a search of PubMed and Google Scholar. Full article texts were reviewed. Reference lists were screened for additional articles and books. 37 basic articles in journals including ones written in German and three basic articles in books were identified.

RESULTS

Glycogen staining of the ectocervical squamous epithelium with iodine goes back to Paul Ehrlich (1854-1915). Walter Schiller (1887-1960) examined nearly 200 different dyes and found that vital staining of the cervical squamous epithelium was best achieved with Lugol's iodine solution, which was indicated by Jean Guillaume Lugol (1786-1851) for disinfection of the vagina. In 1928 W. Lahm observed that the glycogen content of a squamous epithelium cell decreases as anaplasia increases. From the outset, H. Hinselmann included the iodine test in the minimum requirements for colposcopy. In 1946 H. J. Wespi first mentioned the finding of an "uncharacteristic iodine negative area." The first international colposcopic terminology from Graz in 1975 lists the "iodine light area" among the different colposcopy findings. The IFCPC nomenclatures from Rome 1990, Barcelona 2002, and Rio de Janeiro 2011 have evaluated the iodine test and classified their findings differently. A breakthrough to effective cervical cancer screening in resource-limited settings in Africa, India, and Latin America was achieved with R. Sankaranarayanan's publication on naked-eye visual inspection of the cervix after application of Lugol's iodine.

CONCLUSIONS

This paper is a step toward a better understanding of what we think and do today with iodine testing and what problems and upcoming tasks will arise in future.

Reproductive tract biology: Of mice and men

The study of male and female reproductive tract development requires expertise in two separate disciplines, developmental biology and endocrinology. For ease of experimentation and economy, the mouse has been used extensively as a model for human development and pathogenesis, and for the most part similarities in developmental processes and hormone action provide ample justification for the relevance of mouse models for human reproductive tract development. Indeed, there are many examples describing the phenotype of human genetic disorders that have a reasonably comparable phenotype in mice, attesting to the congruence between mouse and human development. However, anatomic, developmental and endocrinologic differences exist between mice and humans that (1) must be appreciated and (2) considered with caution when extrapolating information between all animal models and humans. It is critical that the investigator be aware of both the similarities and differences in organogenesis and hormone action within male and female reproductive tracts so as to focus on those features of mouse models with clear relevance to human development/pathology. This review, written by a team with extensive expertise in the anatomy, developmental biology and endocrinology of both mouse and human urogenital tracts, focusses upon the significant human/mouse differences, and when appropriate voices a cautionary note regarding extrapolation of mouse models for understanding development of human male and female reproductive tracts.

Malignant transformation of vaginal adenosis to clear cell carcinoma without prenatal diethylstilbestrol exposure: a case report and literature review

Background

We report an extremely rare case of vaginal clear cell carcinoma, which originated from the malignant transformation of vaginal adenosis without prenatal diethylstilbestrol (DES) exposure.

Case presentation

In this case, the patient was a Chinese woman with a history of two decades of intermittent vaginal pain, sexual intercourse pain and vaginal contact bleeding. On September 1, 2011, when the patient was 39 years old, a vaginal biopsy revealed vaginal adenosis. After intermittent drug and laser treatment, her symptoms did not improve. Four years later, on March 4, 2015, another vaginal biopsy for abnormal vaginal cytology revealed atypical vaginal adenosis. After treatment with sirolimus, her symptoms and abnormal vaginal cytology results persisted, and she underwent laparoscopic hysterectomy with bilateral salpingo-oophorectomy and excision of the vaginal lesions. One year after the hysterectomy, on August 15, 2017, the vaginal cytology results suggested atypical glandular cells, and a biopsy revealed vaginal clear cell carcinoma originating from the atypical vaginal adenosis. A wide local resection of the vaginal lesions was performed, followed by concurrent chemoradiotherapy. Regular follow-up over 16 months showed no evidence of the recurrence of vaginal adenosis or cancer.

Conclusions

Based on the evolution of a series of pathological evidence, we report the fourth case in the world of vaginal clear cell carcinoma originating from vaginal adenosis without prenatal DES exposure. Wide local excision with radiotherapy provided at least 16 months of disease-free survival.

Development of the human female reproductive tract

Development of the human female reproductive tract is reviewed from the ambisexual stage to advanced development of the uterine tube, uterine corpus, uterine cervix and vagina at 22 weeks. Historically this topic has been under-represented in the literature, and for the most part is based upon hematoxylin and eosin stained sections. Recent immunohistochemical studies for PAX2 (reactive with Müllerian epithelium) and FOXA1 (reactive with urogenital sinus epithelium and its known pelvic derivatives) shed light on an age-old debate on the derivation of vaginal epithelium supporting the idea that human vaginal epithelium derives solely from urogenital sinus epithelium. Aside for the vagina, most of the female reproductive tract is derived from the Müllerian ducts, which fuse in the midline to form the uterovaginal canal, the precursor of uterine corpus and uterine cervix an important player in vaginal development as well. Epithelial and mesenchymal differentiation markers are described during human female reproductive tract development (keratins, homeobox proteins (HOXA11 and ISL1), steroid receptors (estrogen receptor alpha and progesterone receptor), transcription factors and signaling molecules (TP63 and RUNX1), which are expressed in a temporally and spatially dynamic fashion. The utility of xenografts and epithelial-mesenchymal tissue recombination studies are reviewed.

Recommended standardized terminology of the anterior female pelvis based on a structured medical literature review

BACKGROUND

The use of imprecise and inaccurate terms leads to confusion amongst anatomists and medical professionals.

OBJECTIVE

We sought to create recommended standardized terminology to describe anatomic structures of the anterior female pelvis based on a structured review of published literature and selected text books.

STUDY DESIGN

We searched MEDLINE from its inception until May 2, 2016, using 11 medical subject heading terms to identify studies reporting on anterior female pelvic anatomy; any study type published in English was accepted. Nine textbooks were also included. We screened 12,264 abstracts, identifying 200 eligible studies along with 13 textbook chapters from which we extracted all pertinent anatomic terms.

RESULTS

In all, 67 unique structures in the anterior female pelvis were identified. A total of 59 of these have been previously recognized with accepted terms in Terminologia Anatomica, the international standard on anatomical terminology. We also identified and propose the adoption of 4 anatomic regional terms (lateral vaginal wall, pelvic sidewall, pelvic bones, and anterior compartment), and 2 structural terms not included in Terminologia Anatomica (vaginal sulcus and levator hiatus). In addition, we identified 2 controversial terms (pubourethral ligament and Grafenberg spot) that require additional research and consensus from the greater medical and scientific community prior to adoption or rejection of these terms.

CONCLUSION

We propose standardized terminology that should be used when discussing anatomic structures in the anterior female pelvis to help improve communication among researchers, clinicians, and surgeons.

Higher sequence diversity in the vaginal tract than in blood at early HIV-1 infection

In the majority of cases, human immunodeficiency virus type 1 (HIV-1) infection is transmitted through sexual intercourse. A single founder virus in the blood of the newly infected donor emerges from a genetic bottleneck, while in rarer instances multiple viruses are responsible for systemic infection. We sought to characterize the sequence diversity at early infection, between two distinct anatomical sites; the female reproductive tract vs. systemic compartment. We recruited 72 women from Uganda and Zimbabwe within seven months of HIV-1 infection. Using next generation deep sequencing, we analyzed the total genetic diversity within the C2-V3-C3 envelope region of HIV-1 isolated from the female genital tract at early infection and compared this to the diversity of HIV-1 in plasma. We then compared intra-patient viral diversity in matched cervical and blood samples with three or seven months post infection. Genetic analysis of the C2-V3-C3 region of HIV-1 env revealed that early HIV-1 isolates within blood displayed a more homogeneous genotype (mean 1.67 clones, range 1–5 clones) than clones in the female genital tract (mean 5.7 clones, range 3–10 clones) (p<0.0001). The higher env diversity observed within the genital tract compared to plasma was independent of HIV-1 subtype (A, C and D). Our analysis of early mucosal infections in women revealed high HIV-1 diversity in the vaginal tract but few transmitted clones in the blood. These novel in vivo finding suggest a possible mucosal sieve effect, leading to the establishment of a homogenous systemic infection.

During chronic HIV-1 infection, high viral diversity can be found in the blood and semen of donors. However, a single HIV-1 clone establishes productive infection in the recipient following heterosexual transmission. To investigate the genetic bottleneck occurring at the earliest stages of heterosexual HIV-1 transmission, we characterized the HIV-1 envelope sequence diversity at very early and early stages of infection in the female reproductive tract and matched plasma samples from a cohort of Ugandan and Zimbabwean women. A more diverse viral population was observed in the endocervical swab samples compared to plasma. Endocervical samples harbored a larger number of viral clones, while in the majority of plasma samples only a single clone was present early in infection. Interestingly, these observations were independent of HIV-1 subtype, hormonal contraceptive use or the number of sex acts and partners. Furthermore, in the cases of higher HIV-1 diversity in the blood during early infection, faster CD4 T cell decline were observed during chronic disease suggesting faster disease progression. Our findings provide novel in vivo evidence for the existence of an intra-patient genetic bottleneck restricting the HIV-1 from the vaginal tract to the blood during early heterosexual HIV-1 transmission.

New insights into human female reproductive tract development

We present a detailed review of the embryonic and fetal development of the human female reproductive tract utilizing specimens from the 5th through the 22nd gestational week. Hematoxylin and eosin (H&E) as well as immunohistochemical stains were used to study the development of the human uterine tube, endometrium, myometrium, uterine cervix and vagina. Our study revisits and updates the classical reports of Koff (1933) and Bulmer (1957) and presents new data on development of human vaginal epithelium. Koff proposed that the upper 4/5ths of the vagina is derived from Müllerian epithelium and the lower 1/5th derived from urogenital sinus epithelium, while Bulmer proposed that vaginal epithelium derives solely from urogenital sinus epithelium. These conclusions were based entirely upon H&E stained sections. A central player in human vaginal epithelial development is the solid vaginal plate, which arises from the uterovaginal canal (fused Müllerian ducts) cranially and squamous epithelium of urogenital sinus caudally. Since Müllerian and urogenital sinus epithelium cannot be unequivocally identified in H&E stained sections, we used immunostaining for PAX2 (reactive with Müllerian epithelium) and FOXA1 (reactive with urogenital sinus epithelium). By this technique, the PAX2/FOXA1 boundary was located at the extreme caudal aspect of the vaginal plate at 12 weeks. During the ensuing weeks, the PAX2/FOXA1 boundary progressively extended cranially such that by 21 weeks the entire vaginal epithelium was FOXA1-reactive and PAX2-negative. This observation supports Bulmer's proposal that human vaginal epithelium derives solely from urogenital sinus epithelium. Clearly, the development of the human vagina is far more complex than previously envisioned and appears to be distinctly different in many respects from mouse vaginal development.

Use of Mueller matrix polarimetry and optical coherence tomography in the characterization of cervical collagen anisotropy

Preterm birth (PTB) presents a serious medical health concern throughout the world. There is a high incidence of PTB in both developed and developing countries ranging from 11% to 15%, respectively. Recent research has shown that cervical collagen orientation and distribution changes during pregnancy may be useful in predicting PTB. Polarization imaging is an effective means to measure optical anisotropy in birefringent materials, such as the cervix's extracellular matrix. Noninvasive, full-field Mueller matrix polarimetry (MMP) imaging methodologies, and optical coherence tomography (OCT) imaging were used to assess cervical collagen content and structure in nonpregnant porcine cervices. We demonstrate that the highly ordered structure of the nonpregnant porcine cervix can be observed with MMP. Furthermore, when utilized ex vivo, OCT and MMP yield very similar results with a mean error of 3.46% between the two modalities.

Benign intestinal glandular lesions in the vagina: a possible correlation with implantation

BACKGROUND

Enteric-type glandular lesions are extremely rare in the vagina. Their histological origin remains a matter of speculation at present.

METHOD

We review two rectal mucosal prolapse-like polyps and one intestinal-type adenosis in the vagina.

RESULTS

Case 1, a 64-year-old woman, presented with a vaginal polypoid lesion with a size of 4 × 3 × 3 cm. Case 2, an 8-year-old girl, had a 1.5 × 1.5 × 0.8-cm pedunculated polyp in the vaginal navicular fossa and a clinically suspected rectovaginal fistula. Case 1 and 3 had an obsolete severe perineal laceration. On histopathological examination, cases 1 and 2 resembled rectal mucosal prolapse or inflammatory cloacogenic polyp (rectal mucosal prolapse-like polyp). Case 3 had an incidental intestinal-type adenosis in the removed vaginal wall. Immunohistochemistry confirmed the intestinal differentiation in all 3 lesions by showing diffuse CDX2-positive, CK20-positive, and scattered chromogranin A-positive neuroendocrinal cells in the lower compartment of the crypt.

CONCLUSIONS

In summary, we report herein three unusual cases of benign intestinal-type glandular lesions in the vagina including two rectal mucosal prolapse-like polyps and one case of intestinal-type adenosis, and discuss possibilities for their histogenetic basis.

Is Cryotherapy Friend or Foe for Symptomatic Cervical Ectopy?

OBJECTIVE

To evaluate the success rates and clinical outcomes of cervical cryotherapy applied to cervical ectopy for symptomatic relief.

SUBJECTS AND METHODS

A total of 124 women who underwent cryotherapy for symptomatic treatment of cervical ectopy were included in this study. Indications for treatment were: abundant leucorrhoea (n = 114), post-coital bleeding (n = 22), recurrent cervicitis (n = 30) and pelvic pain (n = 12). Cryotherapy consisted of the use of carbon dioxide at -89°C to destroy the ectopic columnar epithelium by freezing, and it was transmitted to the ectopy through a flat cryoprobe. No routine anaesthesia or analgesia was administered. All patients were questioned about the status of their symptoms after 6 weeks of treatment.

RESULTS

The highest success rate was obtained in patients with abundant leucorrhoea (n = 102; 89.5%), while the lowest success rate was achieved in subjects with pelvic pain (n = 7; 58%). After treatment, no severe complications were observed, except for hydrorrhoea for a few days. Success rates were 9 times lower in patients who had 3 or more cervicitis episodes per 6 months.

CONCLUSION

In this study, the success rate of cryotherapy was highest in patients with abundant leucorrhoea and lowest in patients with pelvic pain and recurrent cervicitis. Hence, we recommend that clinicians perform the procedure in such patients without much delay.

Explanation and Use of the Rio 2011 Colposcopy Nomenclature of the IFCPC (International Federation for Cervical Pathology and Colposcopy): Comments on the general colposcopic assessment of the uterine cervix: adequate/inadequate; squamocolumnar junction; transformation zone

In July 2012 the IFCPC adopted a revised terminology for colposcopic examinations of the uterine cervix. In 2012, the Boards of the Arbeitsgemeinschaft Kolposkopie (AGK - Austrian Society of Colposcopy), the Arbeitsgemeinschaft für Kolposkopie und Zervixpathologie (AGKOL - Swiss Society of Colposcopy and Cervical Pathology) and the Arbeitsgemeinschaft für Kolposkopie und Zervixpathologie (AGCPC - German Society of Colposcopy and Cervical Pathology) accepted the validity of the 2011 IFCPC nomenclature and recommended its use in general clinical practice across German-speaking countries. The revised nomenclature was devised so that examiners can evaluate colposcopic criteria according to a specific scheme. At the start of the examination, the examiner must assess whether the colposcopy is representative or not. 1. Can the examination be classed as adequate or inadequate (reasons must be given)? 2. How would you describe the visibility of the squamocolumnar junction and categorize the transformation zone? Below we discuss some aspects of this general assessment as outlined in the nomenclature which were found to require further clarification for general practice.