HPV and vaginal microecological disorders in infertile women: a cross-sectional study in the Chinese population

From infection to infertility: a review of the role of human papillomavirus-induced oxidative stress on reproductive health and infertility

Infertility has emerged as a significant global health concern, affecting nearby 8-12% of couples in reproductive age worldwide. Increasing evidence suggests a potential link between human papillomavirus (HPV) and infertility in both men and women. Some research indicate that HPV can infect various components of semen, potentially affecting sperm quality by decreasing motility, viability, and increasing DNA fragmentation, all of which may contribute to male infertility. The virus can attach to the equatorial region of the sperm head, enabling infected sperm to transmit the virus to the oocyte or placenta. Consequently, HPV potentially induces apoptosis in trophoblastic cells and disrupts their adhesion to endometrial cells, which raises the risk of miscarriage. HPV may also affect ovarian reserve by causing chronic inflammation, which can impair granulosa cell function and lower serum anti-Müllerian hormone (AMH) levels. Besides, HPV-related immune responses also contribute to infertility by producing anti-sperm antibodies (ASAs), which cause sperm clumping, reduce motility through cervical mucus, activate the complement system that damages sperm in the female reproductive tract and interfere with sperm-egg interactions. Moreover, HPV infection has been linked to reduced success rates in assisted reproductive technologies (ART), potentially disrupting critical processes such as the acrosome reaction, sperm-oocyte interaction, and fusion. One potential mechanism through which HPV contributes to infertility is oxidative stress (OS). Triggered OS can negatively impact sperm quality and cause damage to the female reproductive system, ultimately contributing to infertility. Despite these associations, the precise mechanisms and the strength of the relationship remain uncertain. Thus, this review seeks to investigate the potential impact of HPV on infertility, particularly its effects on the reproductive system through OS. A clearer understanding of these processes could inform future health strategies for addressing HPV-related infertility.

Comparison of microbial abundance and diversity in uterine and peritoneal fluid in infertile patients with or without endometriosis

INTRODUCTION

Endometriosis (EM) is a multifactorial disease that affects 10 - 15% of women of reproductive age. Additionally, 30-50% of women with EM suffer from infertility. The mechanism of infertility caused by EM has not yet been consistently explained. In recent years, studies have shown a link between infertility associated with EM and changes in the reproductive tract microbiota.

METHODS

In this study, we involved 26 EM patients (8 cases of stage I-II and 18 cases of stage III-IV) and 31 control subjects who were tubal obstruction-related infertility (TORI). The samples from peritoneal fluid (PF) and uterine fluid (UF) were collected and sequenced by 16 S rRNA amplicon.

RESULTS

In the comparison of microbial diversity, we found no significant differences in the microbial diversity of PF and UF between patients with stage I-II EM and those with TORI. However, there was a significant difference in microbial diversity among patients with stage III-IV EM compared to the previous two groups. Lactobacillus decreased in PF of EM compared to the control group, while it increased in UF. In PF, the abundance of Pseudomonas, Enterococcus, Dubosiella and Klebsiella was significantly higher in patients with stage III-IV compared to TORI patients. And in UF, the main differences existed between stage I-II EM compared to the other two groups. The abundance of pontibacter, aquabacterium, Rikenellaceae and so on at the genus level was significantly enriched in the EM patients with stage I-II. In the analysis based on KEGG database, EM may affect the receptivity related pathways of the endometrium by influencing changes in the uterine microbiota.

CONCLUSION

Our results indicated that as EM progresses, the microorganisms in UF and PF keep changing. These changes in the microbiota, as well as the resulting alternations in gene functional classification, may play an important role in the infertility associated with EM.

HPV infection and vaginal microecological disorders in women with intrauterine adhesion: cross-sectional study in a Chinese population

BACKGROUND

The purpose of this study was to evaluate the vaginal microecology and the distribution of human papillomavirus (HPV) subtypes in patients with uterine adhesions and explore the correlation between HPV infection and vaginal microecology imbalance and the occurrence of intrauterine adhesion (IUA).

METHODS

A total of 479 women were enrolled in the study, including 259 in the normal group and 220 in the IUA group. Vaginal microecological and HPV analyses were performed on all participants. Significant differences between the two groups were analyzed, and Spearman correlation analysis was performed.

RESULTS

The incidence of IUA in patients between 31 and 40 years of age was high. The I-II degree of vaginal cleanliness in the IUA group was significantly lower than that in the normal group, and the number of III-IV degree was significantly higher than that in the normal group. Moreover, the incidences of VVC (vulvovaginal candidiasis) and vaginal disorders and infections with HPV 16 and HPV 52 subtypes were significantly higher in the IUA group than in the normal group. The incidence of high-risk HPV infection combined with vaginal disorders in the IUA group was higher than that in the normal group. Correlation analysis showed that the occurrence of IUAs was positively correlated with HPV infection and negatively correlated with PH and vaginal microecological imbalance.

CONCLUSION

The HPV infection rate and vaginal microecology disorders affect the occurrence of IUAs. For patients with IUAs, control of the HPV infection rate and the prevention of vaginal microecological disorders should be improved.

Characterization of vaginal Lactobacillus species as a predictor of fertility among Iranian women with unexplained recurrent miscarriage and fertile women without miscarriage history using machine learning modeling

BACKGROUND

Lactobacillus spp. are the predominant bacteria of the vaginal tract, the alteration of which has been previously linked to miscarriage. Here, we investigated differences between selected vaginal Lactobacillus species of women with a history of recurrent miscarriages and fertile women without a history of miscarriage in Iran.

METHODS AND RESULTS

Vaginal swabs were taken from 29 fertile and 24 infertile women and quantitative real-time PCR (qPCR) assay was used to determine a selection of vaginal Lactobacillus species in both groups. The logistic regression (LR) model, Naive Bayes (NB) model, support vector machine model (SVM), and neural network model (NN) were developed to predict disease outcome by selected variables. LR analysis was used to construct a nomogram indicating predictions of the risk of miscarriage. The most abundant species among the patients were L. rhamnosus, L. ruminis, and L. acidophilus, while L. gasseri, L. vaginalis, L. fermentum, and L. iners were more abundant in healthy subjects. The distribution of L. ruminis, L. iners, and L. rhamnosus was higher in patients, while L. acidophilus, L. gasseri, and L. fermentum were highly distributed among healthy subjects. Higher AUC in predicting the disease outcome was observed for L. gasseri, L. rhamnosus, L. fermentum, and L. plantarum.

CONCLUSION

Our findings provide experimental evidence of vaginal Lactobacillus imbalance in infertile women and a suitable predictor for miscarriage based on the AUC algorithms. Further studies with larger sample size and using high-throughput technologies are needed to boost our understanding of the role of lactobacilli in miscarriage.

Review of the evidence of the effects of human papillomavirus infection and Gardnerella vaginalis, and their co-infection on infertility

A prevalent sexually transmitted infection, the human papillomavirus (HPV) is typically obtained just after the first sexual activity. The majority of HPV infections are asymptomatic and temporary. Cervical, anal, penile, vaginal, vulvar, and oropharyngeal cancers can occur due to recurrent infections with high-risk (hr)-HPV strains, generally decades later. Infections with HPV are significantly associated with reproductive function abnormalities. Per recent research, HPV infections may result in male infertility by reducing sperm motility. The hr-HPV infection was a risk factor for miscarriage, and the indiscriminate HPV genotype increased the probability of premature labor unexpectedly. Women's endometrial trophoblastic cell implantation is decreased by HPV. Gardnerella vaginalis (GV), an anaerobic bacterium that is a component of the natural vaginal flora, can be associated with bacterial vaginosis (BV) when it starts to overgrow and emerge as the dominant species. Reduced Lactobacillus species abundance and GV are linked to female infertility. Data from in vitro studies suggests that sialidase produced by GV may facilitate the entry and growth of papilloma and other sexually transmitted viruses. Also, based on some studies conducted in the past, it can be said that GV and BV are associated with the development of uterine cancer. However, there is still not enough information about the exact mechanism of GV and HPV in causing infertility, which requires more research.