Association of Sexual Debut in Adolescents With Microbiota and Inflammatory Markers

Specific vaginal and gut microbiome and the anti-tumor effect of butyrate in cervical cancer women

OBJECTIVE

To investigate the vaginal and gut microbes changes during the carcinogenesis of cervical and the auxiliary diagnostic value. To investigate the effect of microbiome-specific metabolites butyric on cervical cancer cells.

METHODS

We studied 416 vaginal 16S rRNA sequencing data and 116 gut sequencing data. Reads were processed using VSEARCH. We used Shannon index, Chao1 index, Simpson diversity index, β diversity index, Linear discriminant analysis Effect Size (LEfSe), co-abundance network and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis to explore microbiome differences between groups. We constructed random forest models based on genus and verified its discriminant effect. Finally, we used the cell counting kit-8 (CCK-8) method to detect cell proliferation capacity and flow cytometry to detect apoptosis and induction of cell cycle progression.

RESULTS

Compared to the non-cancerous population, patients with cervical cancer had unique microbial community characteristics in both vaginal and gut ecological niches. Our predictive model based on genus in two ecological regions achieved high accuracy in the diagnosis of cervical cancer (vaginal model AUC=91.58 %; gut model AUC=99.95 %). Butyric inhibited cervical cancer cell proliferation in a concentration-dependent manner and promoted apoptosis of cancer cells.

CONCLUSION

Significant differences were found in vaginal and gut microbes in patients with cervical cancer compared to the non-cancerous population. The prediction models constructed at the genus level in both ecological sites have good diagnostic value. Microorganisms may be involved in cervical cancer progression in a metabolite-dependent way, and targeting butyric may provide therapeutic options for cervical cancer.

Low prevalence of bacterial vaginosis in Kenyan adolescent girls and rapid incidence after first sex

BACKGROUND

Bacterial vaginosis is a risk factor for sexually transmitted infections, including HIV. Adult African women have a high prevalence of bacterial vaginosis, but it is not known when first bacterial vaginosis occurs.

OBJECTIVE

This study aimed to describe bacterial vaginosis in younger African women, before and after first sex, and to determine the incidence of bacterial vaginosis and significant correlates of bacterial vaginosis incidence and recurrence.

STUDY DESIGN

In a prospective observational cohort study enrolling adolescents with limited sexual experience, young women aged 16 to 21 years were recruited in Thika, Kenya. Eligible participants were HIV and herpes simplex virus 2 seronegative and reported 0 or 1 lifetime sexual partner. The Nugent score was determined at quarterly visits from vaginal Gram stains. The trends in bacterial vaginosis were described over time; hazard ratios were calculated using Cox regression, and relative risk of bacterial vaginosis was estimated using generalized estimating equations and Poisson regression.

RESULTS

A total of 400 participants with a median age of 18.6 years (interquartile range, 16-21) were enrolled. Of note, 322 participants (80.5%) reported no history of sex, whereas 78 participants (19.5%) reported sex with 1 partner. At enrollment, bacterial vaginosis (Nugent score of ≥7) was uncommon (21/375 [5.6%]). Overall, 144 participants had bacterial vaginosis at least once, for an incidence rate of 16.5 cases per 100 person-years. Before first sex, bacterial vaginosis was present at 2.8% of visits, compared with 13.7% of visits after first sex. An adjusted model of bacterial vaginosis incidence observed that first sex was associated with more than a 2-fold increased bacterial vaginosis risk (adjusted hazard ratio, 2.44; 95% confidence interval, 1.25-4.76; P=.009). Chlamydia diagnosis (adjusted hazard ratio, 1.73; 95% confidence interval, 1.1-2.8; P=.02), and herpes simplex virus 2 seropositivity (adjusted hazard ratio, 2.88; 95% confidence interval, 1.17-7.09; P=.021) were both associated with incident bacterial vaginosis. A multivariate generalized estimating equation model, including all episodes of bacterial vaginosis, demonstrated risk factors, including first sex, sexually transmitted infections, urban residence, recent sex, and no income; the most important risk factor was first sex (adjusted relative risk, 1.92; 95% confidence interval, 1.12-3.31; P=.018). The probability of bacterial vaginosis increased with each subsequent episode; mean Nugent scores increased after each bacterial vaginosis episode.

CONCLUSION

Using detailed longitudinal observation, this study found that Kenyan adolescents have almost no bacterial vaginosis before first sex and that initiation of sexual activity was the strongest risk factor for both prevalent bacterial vaginosis and incident bacterial vaginosis.

Starting to have sexual intercourse is associated with increases in cervicovaginal immune mediators in young women: a prospective study and meta-analysis

Background

Adolescent girls and young women (AGYW) are at high risk of sexually transmitted infections (STIs). It is unknown whether beginning to have sexual intercourse results in changes to immune mediators in the cervicovaginal tract that contribute to this risk.

Methods

We collected cervicovaginal lavages from Kenyan AGYW in the months before and after first penile-vaginal sexual intercourse and measured the concentrations of 20 immune mediators. We compared concentrations pre- and post-first sex using mixed effect models. We additionally performed a systematic review to identify similar studies and combined them with our results by meta-analysis of individual participant data.

Results

We included 180 samples from 95 AGYW, with 44% providing only pre-first sex samples, 35% matched pre and post, and 21% only post. We consistently detected 19/20 immune mediators, all of which increased post-first sex (p<0.05 for 13/19; Holm-Bonferroni-adjusted p<0.05 for IL-1β, IL-2, and CXCL8). Effects remained similar after excluding samples with STIs and high Nugent scores. Concentrations increased cumulatively over time after date of first sex, with an estimated doubling time of about 5 months.Our systematic review identified two eligible studies, one of 93 Belgian participants, and the other of 18 American participants. Nine immune mediators were measured in at least two-thirds of studies. Meta-analysis confirmed higher levels post-first sex for 8/9 immune mediators (p<0.05 for six mediators, most prominently IL-1α, IL-1β, and CXCL8).

Conclusions

Cervicovaginal immune mediator concentrations were higher in women who reported that they started sexual activity. Results were consistent across three studies conducted on three different continents.

Funding

This research was funded by R01 HD091996-01 (ACR), by P01 AI 030731-25 (Project 1) (AW), R01 AI116292 (FH), R03 AI154366 (FH) and by the Center for AIDS Research (CFAR) of the University of Washington/Fred Hutchinson Cancer Research Center AI027757.

Vaginal microbiota as an unusual cause of spondylodiscitis

The incidence of extra pelvic infections due to vaginal microflora bacteria has increased as growth media and methods of isolation have improved. However, bone infections seem to be still relatively rare, and little is known about their risk factors, clinical presentation, treatment and final outcome. We describe here a spondylodiscitis due to Gardnerella vaginalis, Atopobium vaginae, Peptostreptococcus indolicus and Prevotella amnii, anaerobic bacteria from vaginal microbiota. Our patient had no obvious predisposing factor and recovered after antibiotic treatment. To our knowledge, this case is the first reported spondylodiscitis caused by polymicrobial vaginal flora in a healthy, immunocompetent woman.

The Vaginal Microbiome: I. Research Development, Lexicon, Defining "Normal" and the Dynamics Throughout Women's Lives

OBJECTIVE

This series of articles, titled The Vaginal Microbiome, written on behalf of the International Society for the Study of Vulvovaginal Disease, aims to summarize the current findings and understanding of the vaginal bacterial microbiota, mainly regarding areas relevant to clinicians specializing in vulvovaginal disorders.

MATERIALS AND METHODS

A database search of PubMed was performed, using the search terms "vaginal microbiome" (VMB) with "research," "normal," "neonate," "puberty," "adolescent," "menopause," and "ethnicities," as well as "human microbiome project." Full article texts were reviewed. Reference lists were screened for additional articles.

RESULTS

In the last 2 decades, many studies applying molecular techniques were performed, intending to characterize the vaginal microbiota. These studies advanced our understanding of how vaginal health is defined. The first article in this series focuses on the advancement of VMB research, technical definitions, the definition of "normal" VMB, and the dynamics of VMB throughout women's lives.

CONCLUSIONS

Understanding how microorganisms inhabiting the vagina interact with each other and with the host is important for a more complete understanding of vaginal health. The clinical application of microbial community sequencing is in its beginning, and its interpretation regarding practical clinical aspects is yet to be determined.

Cervical Squamous Intraepithelial Lesions Are Associated with Differences in the Vaginal Microbiota of Mexican Women

Cervical cancer is an important health concern worldwide and is one of the leading causes of death in Mexican women. Previous studies have shown changes in the female genital tract microbe community related to human papillomavirus (HPV) infection and cervical cancer; yet, this link remains unexplored in many human populations. This study evaluated the vaginal bacterial community among Mexican women with precancerous squamous intraepithelial lesions (SIL). We sequenced the V3 region of the 16S rRNA gene in cervical samples from 228 Mexican women, including 121 participants with SIL, most of which were HPV positive, and 107 healthy women without HPV infection or SIL. The presence of SIL was associated with changes in composition (beta diversity) and with a higher species richness (Chao1). A comparison of HPV-positive women with and without SIL showed that microbiota changes occurred even in the absence of SIL. Multivariate association with linear models (MaAsLin) analysis yielded independent associations between HPV infection and an increase in the relative abundance of Brachybacterium conglomeratum and Brevibacterium aureum as well as a decrease in two Lactobacillus iners operational taxonomic units (OTUs). We also identified a positive independent association between HPV-16, the most common HPV subtype linked to SIL, and Brachybacterium conglomeratum. Our work indicates that HPV infection leading to SIL is primarily associated with shifts in vaginal microbiota composition, some of which may be specific to this human population.

IMPORTANCE Human papillomavirus (HPV) plays a critical role in cervical carcinogenesis but is not sufficient for cervical cancer development, indicating the involvement of other factors. The vaginal microbiota is an important factor in controlling infections caused by HPV, and, depending on its composition, it can modulate the microenvironment in vaginal mucosa against viral infections. Ethnic and sociodemographic factors influence differences in vaginal microbiome composition, which underlies the dysbiotic patterns linked to HPV infection and cervical cancer across different populations of women. Here, we provide evidence for associations between vaginal microbiota patterns and HPV infection linked to ethnic and sociodemographic factors. To our knowledge, this is the first report of the species Brevibacterium aureum and Brachybacterium conglomeratum linked to HPV infection or squamous intraepithelial lesions (SIL).

Cytokine response following perturbation of the cervicovaginal milieu during HPV genital infection

Human papillomaviruses (HPVs) are oncogenic viruses causing most cervical cancers. Highly prevalent in young, sexually active women, only a minority of HPV infections persist. To better characterize the immuno-modulatory impact of early HPV infections, we measured changes in a panel of 20 cytokines in cervicovaginal samples collected from young women who were tested for HPV and self-reported for genital inflammation and infection symptoms. Multi-factor statistical analyses revealed that increased IL-1Alpha and IL-12/IL-23p40 concentrations were associated with HPV infection and that macrophage inflammatory proteins were associated in particular with high-risk HPV infections. ClinicalTrials.gov identifier NCT02946346.

Influence of dapivirine vaginal ring use on cervicovaginal immunity and functional microbiome in adolescent girls

OBJECTIVE

The antiretroviral-based dapivirine vaginal ring reduced HIV risk among women in phase III clinical trials. However, limited data exists on the impact of dapivirine on the vaginal microenvironment in adolescents.

DESIGN

A comprehensive metaproteomics approach was used to assess host proteome and microbiome changes in cervicovaginal mucus with dapivirine ring use in adolescents enrolled in the MTN-023/IPM 030 (MTN-023) trial.

METHODS

Participants were randomized 3 : 1 to use dapivirine or placebo vaginal rings monthly for 6 months. Cervicovaginal samples from a subset of 35 participants (8 placebo, 27 dapivirine) were analyzed.

RESULTS

Mass spectrometry analysis identified 405 human and 2467 bacterial proteins belonging to 15 unique genera. The host proteome belonged to many functional pathways primarily related to inflammation. When stratified by study treatment arm, 18 (4.4%) and 28 (6.9%) human proteins were differentially abundant (adjusted P < 0.05) between baseline and follow-up in the placebo and dapivirine arms, respectively. The vaginal microbiome was predominantly composed of Lactobacillus, Gardnerella, and Prevotella. Although bacterial taxa did not differ by arm or change significantly, Lactobacillus crispatus increased (P < 0.001) and Lactobacillus iners decreased (P < 0.001) during the 6-month follow-up. There were no significant differences in bacterial functions by arm or time in the trial. Protected vaginal sex significantly associated with decreased neutrophil inflammatory biomarkers and may be associated with changes in bacterial taxa and metabolism.

CONCLUSION

Condom use may associate with differences to inflammation and bacterial function but dapivirine ring use does not, thereby supporting the mucosal safety profile of this vaginal ring for adolescents.

The Vaginal Microbiota Among Adolescent Girls in Tanzania Around the Time of Sexual Debut

The aetiology of bacterial vaginosis (BV) is not well-understood, and prevalence appears to be higher among women living in sub-Saharan Africa. A recent conceptual model implicates three main bacteria (Gardnerella vaginalis; Atopobium vaginae; and Prevotella bivia), sexual activity, sialidase activity, and biofilm formation in the pathogenesis of BV. We describe the vaginal microbiota, presence of the putative sialidase A gene of G. vaginalis, and biofilm among 386 adolescent girls aged 17 and 18 years in a cross-sectional study in Mwanza, Tanzania around the time of expected sexual debut. Vaginal swabs were collected and tested by quantitative polymerase chain reaction (qPCR) for five Lactobacillus species, G. vaginalis, A. vaginae, P. bivia, the sialidase A gene of G. vaginalis, and by fluorescence in situ hybridisation (FISH) for evidence of G. vaginalis and A. vaginae biofilm. We conducted a risk factor analysis of G. vaginalis, A. vaginae and P. bivia, and explored the associations between biofilm, the presence of the sialidase A gene, and non-optimal vaginal microbiota (Nugent 4-7). L. crispatus and L. iners were detected in 69 and 82% of girls, respectively. The prevalence of L. crispatus was higher than previously reported in earlier studies among East and Southern African women. G. vaginalis, A. vaginae, P. bivia were independently associated with reported penile-vaginal sex. Samples with all three BV-associated bacteria made up the highest proportion of samples with Nugent-BV compared to samples with each bacterium alone or together in pairs. Of the 238 girls with G. vaginalis, 63% had the sialidase A gene detected, though there was no difference by reported sexual activity (p = 0.197). Of the 191 girls with results for sialidase A gene and FISH, there was strong evidence for an increased presence of sialidase A gene among those with evidence of a biofilm (p < 0.001). There was a strong association between biofilm and non-optimal microbiota (aOR67.00; 95% CI 26.72-190.53). These results support several of the steps outlined in the conceptual model, although the role of sexual activity is less clear. We recommend longitudinal studies to better understand changes in vaginal microbiota and biofilm formation around the time of sexual debut.

Results from a cross-sectional sexual and reproductive health study among school girls in Tanzania: high prevalence of bacterial vaginosis

OBJECTIVES

Bacterial vaginosis (BV) increases women's susceptibility to sexually transmitted infections (STIs) and HIV and may partly explain the high incidence of STI/HIV among girls and young women in East and southern Africa. The objectives of this study were to investigate the association between BV and sexual debut, to investigate other potential risk factors of BV and to estimate associations between BV and STIs.

METHODS

Secondary school girls in Mwanza, aged 17 and 18 years, were invited to join a cross-sectional study. Consenting participants were interviewed and samples were obtained for STI and BV testing. Factors associated with prevalent BV were analysed using multivariable logistic regression. Y-chromosome was tested as a biomarker for unprotected penile-vaginal sex.

RESULTS

Of the 386 girls who were enrolled, 163 (42%) reported having ever had penile-vaginal sex. Ninety-five (25%) girls had BV. The prevalence of BV was 33% and 19% among girls who reported or did not report having ever had penile-vaginal sex, respectively. BV was weakly associated with having ever had one sex partner (adjusted odds ratio (aOR) 1.59;95% CI 0.93 to 2.71) and strongly associated with two or more partners (aOR = 3.67; 95% CI 1.75 to 7.72), receptive oral sex (aOR 6.38; 95% CI 1.22 to 33.4) and having prevalent human papillomavirus infection (aOR = 1.73; 95% CI 1.02 to 2.95). Of the 223 girls who reported no penile-vaginal sex, 12 (5%) tested positive for an STI and 7 (3%) tested positive for Y-chromosome. Reclassifying these positive participants as having ever had sex did not change the key results.

CONCLUSIONS

Tanzanian girls attending school had a high prevalence of BV. Increasing number of sex partner was associated with BV; however, 19% of girls who reported no penile-vaginal sex had BV. This suggests that penile-vaginal sexual exposure may not be a prerequisite for BV. There was evidence of under-reporting of sexual debut.

Differential sexual network connectivity offers a parsimonious explanation for population-level variations in the prevalence of bacterial vaginosis: a data-driven, model-supported hypothesis

BACKGROUND

The prevalence of bacterial vaginosis (BV) and vaginal microbiota types varies dramatically between different populations around the world. Understanding what underpins these differences is important, as high-diversity microbiotas associated with BV are implicated in adverse pregnancy outcomes and enhanced susceptibility to and transmission of sexually transmitted infections.

MAIN TEXT

We hypothesize that these variations in the vaginal microbiota can, in part, be explained by variations in the connectivity of sexual networks. We argue: 1) Couple-level data suggest that BV-associated bacteria can be sexually transmitted and hence high sexual network connectivity would be expected to promote the spread of BV-associated bacteria. Epidemiological studies have found positive associations between indicators of network connectivity and the prevalence of BV; 2) The relationship between BV prevalence and STI incidence/prevalence can be parsimoniously explained by differential network connectivity; 3) Studies from other mammals are generally supportive of the association between network connectivity and high-diversity vaginal microbiota.

CONCLUSION

To test this hypothesis, we propose a combination of empirical and simulation-based study designs.

The microbiome in preterm birth

The microbiome is thought to play a role in the maintenance of a healthy pregnancy and thus may either contribute to or protect from preterm birth. Study of the human microbiome has been aided by metagenomic sequencing approaches, providing greater insight into the commensal bacteria that coexist in and on our bodies. The vaginal microbiome has been the most widely studied, though there have been recent efforts to explore the gut, cervical-vaginal, placental and oral microbiomes in the further search of etiologies of preterm birth. To date, a specific microbiome community or microorganism has yet to be reliably associated with preterm birth. This is partly due to the fact that the 'normal' constituents' microbiome can vary widely between healthy individuals. Before our knowledge of the microbiome can be utilized and applied in clinical practice, a greater understanding of the 'healthy' microbiome must be achieved. In particular, we must first appreciate how our microbes influence our biology to promote a healthy pregnancy or alternately render preterm birth.

Immune biomarkers and anti-HIV activity in the reproductive tract of sexually active and sexually inactive adolescent girls

PROBLEM

Adolescent girls are disproportionately affected by the HIV/AIDS pandemic, accounting for 22% of all new HIV infections globally. Yet little is known regarding the immune microenvironment of the adolescent female reproductive tract, especially regarding differences among sexually active and inactive girls, a critical parameter to evaluate HIV susceptibility associated with young age and sexual debut.

METHODS

Cervico-vaginal lavage (CVL) was collected from sexually active (10) and inactive (8) girls aged 11-19 years and analyzed by ELISA for inflammation-associated biomarkers IL-6, IL-8, TNF-α, MIP-3α, IL-1α, IL-1β, matrix metalloproteinases (MMP) 1, 2, 7, 8, and 9, as well as anti-HIV mediators, Elafin, SLPI, human beta-defensin 2, and tissue inhibitor of matrix metalloproteinases (TIMP) 1 and 2. Cervical ectopy was analyzed using Volocity. Anti-HIV activity was determined by TZM-bl assay. Statistical analyses were performed using GraphPad Prism and R.

RESULTS

Sexually inactive girls had significantly higher levels of TNF-α (P = .029) in CVL compared to sexually active girls. In contrast, sexually active girls showed a trend toward higher levels of IL-1α (P = .051) compared to the sexually inactive girls. Heat-map correlations between cervical ectopy and immune biomarkers were also distinct between the 2 populations with significant positive associations between % ectopy and inflammation-associated biomarkers IL-6, IL-1β, IL-8, MIP-3α, MMP-8, and MMP-9 observed in the sexually inactive but not sexually active group.

CONCLUSION

Higher pro-inflammatory biomarker TNF-α, as well as a distinct inflammation-associated immune clustering in sexually inactive girls, can potentially increase risk for infections including HIV upon sexual debut. Future studies with larger sample sizes are needed to characterize the immune parameters associated with sexual activity.