Does the Vaginal Microbiome Operate Differently by Race to Influence Risk of Precervical Cancer?

Differential study on the relationship between HPV infection and vaginal microbiota composition in Uygur and Han women

OBJECTIVE

To analysis the differential composition in vaginal microbial communities following HPV infection in Uygur and Han women, and to Explore the correlation between these difference and the degree of Human Papillomavirus (HPV) infection in Uygur women compared to Han women.

METHODS

A total of 151 Uygur and Han women, with and without HPV, were studied at Xinjiang Uygur Autonomous Region People's Hospital (June 2021-June 2022). These participants were divided into six groups: Uygur control (CV), Uygur transient infection (TPV), Uygur persistent infection (PPV), Han control (CH), Han transient infection (TPH), Han persistent infection (PPH). Vaginal microbiota diversity and dominant bacteria with or without HPV infection were compared using 16S rDNA sequencing.

RESULTS

After HPV infection, vaginal pH increased significantly in Uygur and Han women. Vaginal environment cleanliness decreased notably only in Han women (P < 0.05). In Han women, Lactobacillus and Gardnerella dominated both with or without HPV infection. Prevotella, Streptococcus, and Atopobium decreased, while Sneathia increased significantly in persistent HPV cases. Among Uygur women, Gardnerella, Streptococcus, Prevotella, and Shuttleworthia increased significantly in the TPV group, with lower Lactobacillus compared to CV and PPV groups. Bacterial diversity indices (Chao1, Shannon, Simpson) were significantly lower in TPH compared to CH (P < 0.05), with no significant difference in PPH compared to CH (P > 0.05). Chao1 index was significantly lower in TPH than TPV (P < 0.05), with no difference between PPH and PPV (P > 0.05). CV group's Chao1 index was significantly lower than CH (P < 0.01). PCoA and NMDS analyses showed distinct vaginal microbiota between TPH and TPV groups. LEfSe identified 20 differentially expressed taxa in CH-TPH-PPH comparison and 17 in CV-TPV-PPV.

CONCLUSION

Our study reveals ethnic-specific differences in vaginal microbial responses to HPV infection, with notable alterations in diversity and composition. The differential patterns observed between Uygur and Han women underscore the importance of considering host ethnicity in HPV-related microbial dysbiosis, emphasizing the need for tailored interventions targeting microbial signatures to enhance HPV prevention and management strategies.

A Narrative Review of the Putative Etiologic Role and Diagnostic Utility of the Cervicovaginal Microbiome in Human Papillomavirus-Associated Cervical Carcinogenesis

The cervicovaginal microbiome (CVM) may contribute to human papillomavirus (HPV)-associated cervical carcinogenesis. We summarized the literature on the CVM in cervical carcinogenesis by searching Medline, Web of Science, and Embase for articles that sequenced the CVM using metagenomics. Additionally, we identified studies assessing the diagnostic role of the CVM in cervical carcinogenesis by searching PubMed. We performed an environmental scan of Google and Google Scholar to review common CVM characterization techniques. Twenty-eight records presented or summarized associations between the CVM and HPV acquisition, prevalence, persistence, clearance, and cervical lesions or cancer, while three studies identified bacterial taxa detecting high-risk HPV prevalence or cervical lesions. The area under the curve ranged from 0.802 to 0.952. 16S ribosomal RNA gene sequencing and whole metagenome sequencing have sufficient resolution to study the CVM bacteriome. Bacterial communities may have important implications in cervical cancer; however, there is a need for methodological standardization for CVM characterization.

Suggested Screening Criteria for Gardnerella vaginalis Based on Established Risk Factors

Vaginal infections in women occur due to the downregulation of lactobacilli and the upregulation of Gardnerella vaginalis (GV), leading to bacterial vaginosis (BV). While certain practices are recognized as risk factors for contracting GV infections, this scoping review highlights the severity and importance of other lesser-known risk factors, such as smoking, ethnicity, socioeconomic status (SES), genetics, and anatomy, which can be used to develop an updated point-based screening tool for clinicians. A total of 438 articles were gathered from Embase, Ovid MEDLINE, and Web of Science, and after screening, 31 articles were included. There was a positive association with the presence of GV in those who were sexually active, practiced sexual penetrative vaginal acts, had frequent vaginal and/or receptive oral sexual activity, had unprotected sex, and used insertive contraception (intrauterine device, vaginal rings, and condoms). Women with primary school education levels showed a higher GV colonization increase compared to those with secondary or university education levels, and girls from the highest SES reported the lowest incidence. GV was the predominant bacteria found among sub-Saharan, South African, African Surinamese, Ghanaian, Tanzanian, and Kenyan women. In the USA, self-identified "black" women had a higher prevalence of GV in their vaginal microbiome compared to self-identified "white" women; however, this was the opposite in pregnant women. Significant data show that nicotine use has a strong correlation with increased incidence of GV. Other factors that were found to be associated with GV infections were the increase of sialidase A gene in GV, short cervix (<25mm), and women who performed vaginal douching. Timely screening of GV is vital, especially in high-risk populations, such as pregnant and immunocompromised patients, who may present with more severe and exaggerated symptoms if they contract BV. This paper proposes a numerical scale for evaluating patients' likelihood of contracting a GV infection during their hospital visit.

Effects of vaginal microbiota on human papillomavirus infection and its related diseases

With the knowledge of female reproductive tract microbiota gradually increasing, the connection between vaginal microbiota (VMB) and its related diseases is increasingly highlighted. Manifestation of VMB keeps changing with various dominated bacteria, which can affect the immune response of mucosal barrier and the entrance of pathogens. Human papillomavirus (HPV), as an oncogenic virus, is closely related to viral-associated cancer, such as cervical cancer. According to HPV infection status, VMB can transform into different types, and result in accelerating or restraining the progression of diseases, which have exposed the inner link between VMB and HPV. Therefore, probiotics therapy promises to be a new complementary therapy to rebuild a healthy VMB for patients, but there's still a long way to go before its ready for the clinic. This review focuses on composition, immune response, and application of VMB in HPV and its associated diseases and aims to provide the new ideas and directions for the research on VMB.

Racial Differences in Vaginal Fluid Metabolites and Association with Systemic Inflammation Markers among Ovarian Cancer Patients: A Pilot Study

The vaginal microbiome differs by race and contributes to inflammation by directly producing or consuming metabolites or by indirectly inducing host immune response, but its potential contributions to ovarian cancer (OC) disparities remain unclear. In this exploratory cross-sectional study, we examine whether vaginal fluid metabolites differ by race among patients with OC, if they are associated with systemic inflammation, and if such associations differ by race. Study participants were recruited from the Ovarian Cancer Epidemiology, Healthcare Access, and Disparities Study between March 2021 and September 2022. Our study included 36 study participants with ovarian cancer who provided biospecimens; 20 randomly selected White patients and all 16 eligible Black patients, aged 50-70 years. Acylcarnitines (n = 45 species), sphingomyelins (n = 34), and ceramides (n = 21) were assayed on cervicovaginal fluid, while four cytokines (IL-1β, IL-10, TNF-α, and IL-6) were assayed on saliva. Seven metabolites showed >2-fold differences, two showed significant differences using the Wilcoxon rank-sum test (p < 0.05; False Discovery Rate > 0.05), and 30 metabolites had coefficients > ±0.1 in a Penalized Discriminant Analysis that achieved two distinct clusters by race. Arachidonoylcarnitine, the carnitine adduct of arachidonic acid, appeared to be consistently different by race. Thirty-eight vaginal fluid metabolites were significantly correlated with systemic inflammation biomarkers, irrespective of race. These findings suggest that vaginal fluid metabolites may differ by race, are linked with systemic inflammation, and hint at a potential role for mitochondrial dysfunction and sphingolipid metabolism in OC disparities. Larger studies are needed to verify these findings and further establish specific biological mechanisms that may link the vaginal microbiome with OC racial disparities.

The human vaginal microbiota: from clinical medicine to models to mechanisms

The composition of the vaginal microbiota is linked to numerous reproductive health problems, including increased susceptibility to infection, pregnancy complications, and impaired vaginal tissue repair; however, the mechanisms contributing to these adverse outcomes are not yet fully defined. In this review, we highlight recent clinical advancements associating vaginal microbiome composition and function with health outcomes. Subsequently, we provide a summary of emerging models employed to identify microbe-microbe interactions contributing to vaginal health, including metagenomic sequencing, multi-omics approaches, and advances in vaginal microbiota cultivation. Last, we review new in vitro, ex vivo, and in vivo models, such as organoids and humanized microbiota murine models, used to define and mechanistically explore host-microbe interactions at the vaginal mucosa.