Antibiotic-free vaginal microbiota transplant with donor engraftment, dysbiosis resolution and live birth after recurrent pregnancy loss: a proof of concept case study

The Relationship Between Gut Microbiota and Recurrent Spontaneous Abortion

Recently, the gut microbiota has been found to be associated with multiple organs and systems in the human body, playing a key role in the occurrence and development of various diseases, such as the gut-brain axis and the gut-liver axis. However, its interaction with miscarriages remains poorly understood. This article reviews the characteristics of gut microbiota and its metabolites in patients with recurrent spontaneous abortion (RSA), the mechanism of gut microbiota inducing RSA, and potential therapeutic strategies. Therefore, it provides a new perspective on the gut microbiota in the pathogenesis and treatment of recurrent abortion, and the prospect of the future research direction of gut microbiota and recurrent abortion is proposed based on existing studies.

Endometrial factors and pregnancy loss frequency in recurrent pregnancy loss patients: comparing RT-PCR microbiology, microbial cultures, and immunohistochemistry of endometrium biopsy

The objective of this study is to investigate the presence of bacteria in endometrial samples from patients with recurrent pregnancy loss (RPL) and explore potential correlations between bacterial presence, chronic endometritis, and previous pregnancy loss history. Endometrial samples from 90 RPL patients were analysed using RT-PCR to detect 10 specific bacterial species. A subgroup of 65 patients underwent additional microbial culture and immunohistochemistry for plasma cell identification. Correlations between bacterial presence, chronic endometritis, and the number of previous pregnancy losses were evaluated. We detected at least one out of 10 chosen bacteria DNA by RT-PCR in 24.4% (22/90) of endometrial samples. Patients with PCR-identified bacteria had a significantly higher number of previous pregnancy losses (median 3 vs 2, p = 0.01). No correlation was observed between bacterial presence and chronic endometritis diagnosis. A significant correlation was found between bacterial detection by PCR and microbial culture (p = 0.03), though culture methods detected fewer positive cases. In RPL patients, detecting DNA from at least one of 10 selected bacterial species by RT-PCR correlates with a higher number of previous pregnancy losses. However, this bacterial presence does not correlate with chronic endometritis diagnosis based on the CD138 immunohistochemistry-identified plasma cell count. These findings suggest a potential role of endometrial bacteria in RPL that may be independent of the classical inflammatory response associated with chronic endometritis.

Microbiota transplantation and administration of live biotherapeutic products for the treatment of dysbiosis-associated diseases

INTRODUCTION

The microbiota composition in humans varies according to the anatomical site and is crucial for maintaining homeostasis and an overall healthy state. Several gastrointestinal, vaginal, respiratory, and skin diseases are associated with dysbiosis. Alternative therapies such as microbiota transplantation can help restore microbiota normal composition and can be implemented to treat clinically relevant diseases.

AREAS COVERED

Current microbiota transplantation therapies conducted in clinical trials were included in this review (after searching on MEDLINE database from years 2017 to 2025) such as fecal microbiota transplantation (FMT) against recurrent Clostridioides difficile infection (rCDI) and vaginal microbiota transplantation (VMT) against bacterial vaginosis. Washed microbiota transplantation (WMT) and live biotherapeutic products (LBPs) were also reviewed.

EXPERT OPINION

In microbiota-based transplantation therapy, selecting optimal donors is a limitation. A stool or a vaginal microbiota bank should be implemented to overcome the time-consuming and expensive process of donor recruitment. Microbiota-based LBPs are also promising treatment alternatives for rCDI and other dysbiosis-associated diseases. Specific LBPs could be engineered out of donor fluids-derived strains to achieve the selection of specific beneficial microorganisms for the treatment of specific dysbiosis-associated diseases. Personalized microbiota-based treatments are promising solutions for dysbiosis-associated diseases, which remains an important necessity in clinical practice.

Clinical translation of microbiome research

The landscape of clinical microbiome research has dramatically evolved over the past decade. By leveraging in vivo and in vitro experimentation, multiomic approaches and computational biology, we have uncovered mechanisms of action and microbial metrics of association and identified effective ways to modify the microbiome in many diseases and treatment modalities. This Review explores recent advances in the clinical application of microbiome research over the past 5 years, while acknowledging existing barriers and highlighting opportunities. We focus on the translation of microbiome research into clinical practice, spearheaded by Food and Drug Administration (FDA)-approved microbiome therapies for recurrent Clostridioides difficile infections and the emerging fields of microbiome-based diagnostics and therapeutics. We highlight key examples of studies demonstrating how microbiome mechanisms, metrics and modifiers can advance clinical practice. We also discuss forward-looking perspectives on key challenges and opportunities toward integrating microbiome data into routine clinical practice, precision medicine and personalized healthcare and nutrition.

A nomogram prediction model for embryo implantation outcomes based on the cervical microbiota of the infertile patients during IVF-FET

The microbiota of the female genital tract is crucial for reproductive health. This study aims to investigate the impact of the lower genital tract microbiota on in vitro fertilization and frozen embryo transfer (IVF-FET) outcomes. This study included 131 women aged 20-35 years who underwent their first or second IVF-FET cycle with no obvious unfavorable factors for implantation. Cervical microbiota samples were collected on the embryo transfer day and analyzed using 16S rDNA full-length sequencing. Clinical outcomes were followed up for analysis. Clinical pregnancy (CP) was achieved in 84 patients, and 47 patients experienced non-pregnancy (NP). The cervical microbiota diversity between NP and CP groups showed no significant differences, but some genera such as Halomonas (P = 0.018), Klebsiella (P = 0.039), Atopobium (P = 0.016), and Ligilactobacillus (P = 0.021) were obviously different between the two groups. Notably, there was no significant difference in the abundance of Lactobacillus between the two groups. A nomogram prediction model was developed using the random forest algorithm and logistic regression, including the classification of Halomonas, Atopobium, and Veillonella, as well as the relative abundance of Lactobacillus, to identify high-risk patients with embryo implantation failure. Both internal (area under the curve [AUC] = 0.718, 95% confidence interval [CI]: 0.628-0.807, P < 0.001) and external validation (AUC = 0.654, 95% CI: 0.553-0.755, P = 0.037) of the model performed well. In conclusion, this study established a correlation between cervical microbiota and embryo implantation failure in infertile women undergoing IVF-FET and developed a prediction model that could help in early identification of patients at high risk of implantation failure.IMPORTANCEThis study investigated the potential role of abnormal cervical microbiota in the pathology of implantation failure after in vitro fertilization and frozen embryo transfer (IVF-FET) treatment. Despite nearly half a century of advancements in assisted reproductive technology (ART), the implantation rate of high-quality embryos still hovered around 50%. Moreover, unexplained recurrent implantation failure (RIF) remains a significant challenge in ART. To our knowledge, we first discovered a prediction model for embryo implantation failure, identifying Halomonas and Veillonella as significantly adverse factors for embryo implantation. Despite some limitations, the internal and external validation of the model could bode well for its clinical application prospect. The insights gained from this study pave the way for intervention in the genital tract microbiota prior to IVF-FET, particularly in patients with RIF and RSA.

Partial normalization of microbiota dysbiosis in condyloma acuminatum patients following treatment

Introduction

Condyloma acuminatum (CA) is the most common sexually transmitted disease and the presence of microbiota dysbiosis has been observed to promote the progress of the disease. However, the explicit characteristics of microbiota dysbiosis in CA patients have not been well elucidated yet.

Methods

We recruited 40 CA patients who received QYXJ (an in-hospital prescription that has been used to treat CA for many years) treatment and 40 healthy controls (HC) in the current study. Before and after two weeks QYXJ administration, the skin microbiome of each patient was assessed using 16S rRNA gene sequencing.

Results

Here, we found increased relative abundances of Staphylococcus and Lactobacillus, whereas a decreased Escherichia in CA patients relative to healthy controls (HC). Moreover, we also observed significant alpha and beta diversity differences between the CA and HC groups, and QYXJ treatment effectivity attenuated these alterations of genus level and microbial diversity in patients with CA. Importantly, further microbial interaction and function analyses revealed the significantly enriched relative abundance of Caldivirga and Streptococcus in microbial community, decreased complexity of microbial interactions and downregulated metabolic pathways in CA patients, including membrane transport, lipid metabolism and carbohydrate metabolism. Remarkably, QYXJ administration partially restored these microbiota dysbiosis, which subsequently shifts microbiomes of patients with CA towards healthy-like microbiota.

Conclusion

This study further confirmed the changes of skin microbiome in CA pathogenesis and firstly revealed the protective effects of QYXJ in microbiota dysbiosis resolution, suggesting its potential role as a novel method for CA treatment.

Human microbiome acquisition and transmission

As humans, we host personal microbiomes intricately connected to our biology and health. Far from being isolated entities, our microbiomes are dynamically shaped by microbial exchange with the surroundings, in lifelong microbiome acquisition and transmission processes. In this Review, we explore recent studies on how our microbiomes are transmitted, beginning at birth and during interactions with other humans and the environment. We also describe the key methodological aspects of transmission inference, based on the uniqueness of the building blocks of the microbiome - single microbial strains. A better understanding of human microbiome transmission will have implications for studies of microbial host regulation, of microbiome-associated diseases, and for effective microbiome-targeting strategies. Besides exchanging strains with other humans, there is also preliminary evidence we acquire microorganisms from animals and food, and thus a complete understanding of microbiome acquisition and transmission can only be attained by adopting a One Health perspective.

Unlocking the Interactions Between the Whole-Body Microbiome and HPV Infection: A Literature Review

The human microbiome plays a vital role in maintaining human homeostasis, acting as a key regulator of host immunity and defense mechanisms. However, dysbiotic microbial communities may cause disruption of the symbiotic relationship between the host and the local microbiota, leading to the pathogenesis of various diseases, including viral infections and cancers. One of the most common infectious agents causing cancer is the human papilloma virus (HPV), which accounts for more than 90% of cervical cancers. In most cases, the host immune system is activated and clears HPV, whereas in some cases, the infection persists and can lead to precancerous lesions. Over the last two decades, the advent of next-generation sequencing (NGS) technology and bioinformatics has allowed a thorough and in-depth analysis of the microbial composition in various anatomical niches, allowing researchers to unveil the interactions and the underlying mechanisms through which the human microbiota could affect HPV infection establishment, persistence, and progression. Accordingly, the present narrative review aims to shed light on our understanding of the role of the human microbiome in the context of HPV infection and its progression, mainly to cervical cancer. Furthermore, we explore the mechanisms by which the composition and balance of microbial communities exert potential pathogenic or protective effects, leading to either HPV persistence and disease outcomes or clearance. Special interest is given to how the microbiome can modulate host immunity to HPV infection. Lastly, we summarize the latest findings on the therapeutic efficacy of probiotics and prebiotics in preventing and/or treating HPV infections and the potential of vaginal microbiota transplantation while highlighting the significance of personalized medicine approaches emerging from NGS-based microbiome profiling and artificial intelligence (AI) for the optimal management of HPV-related diseases.

Interconnected microbiomes-insights and innovations in female urogenital health

The paradigm that the vaginal microbiota is a protective gateway for the urinary and reproductive systems has endured for more than a century and driven decades of probiotic research. Evidence robustly supports the notion that healthy urogenital microbiomes are predominantly colonized by lactobacilli, particularly Lactobacillus crispatus, which can acidify the local environment and protect against urogynecologic pathogen colonization. However, recent studies are beginning to delve deeper into the intricate mechanistic interactions connecting the microbiome, its diverse functional potential, host immunity, pathogens, and the development of urogenital diseases. Leveraging these emerging insights alongside past successes presents promising opportunities for future therapies aimed at enhancing the management of conditions such as bacterial vaginosis, urinary tract infections, bladder pain, urinary incontinence, and beyond.

Using In Vitro Models to Study the Interactions Between Environmental Exposures and Human Microbiota

Research has demonstrated a close correlation between human microbiota and overall health, highlighting their intimate connection. Exposure to environmental factors, such as chemical contaminants and biological agents, has the potential to alter the composition and function of microbiota, thereby influencing health outcomes. Meanwhile, microbiota may contribute to host protection by degrading, or rendering harmless, exposures. Environmental exposures demonstrate significant diversity and dynamism; however, conventional methods for exposure-microbiota research, such as animal and epidemiological studies, are often both time-consuming and costly. Additionally, they may raise ethical concerns. This review aimed to examine the existing understanding of employing in vitro models to investigate the interactions between environmental exposures and human microbiota, particularly those located outside the large intestine. A comprehensive search was conducted across the Web of Science, PubMed, and Scopus databases, employing a range of keywords related to microbiota, exposures, and in vitro models. A total of 58 studies fulfilled the search criteria, revealing instances of microbial modulation of exposures and vice versa. It was observed that, although considerable research has been conducted on these interactions in vitro, there remains a pressing need for enhanced model designs and application contexts.

Exploring the Potential Use of Probiotics, Prebiotics, Synbiotics, and Postbiotics as Adjuvants for Modulating the Vaginal Microbiome: a Bibliometric Review

Women's health is related to several factors that include physical, mental, and reproductive health. Additionally, the vaginal microbiota modulation performs a fundamental role in the regulation of physiological homeostasis and dysbiosis, which provides us a potential overview of the use of different biotic agents and their implications for female health. The objective of this work was propitiated insights and conception about the influence of probiotics, prebiotics, synbiotics, and postbiotics as adjuvants for prevention/treatment on the main infections that can affect women's health. Therefore, seventy-one studies published in the Web of Science Core Collection database from 1999 to 2024 were evaluated and performed to a bibliometric analysis employing the VOSviewer software for scientific mapping and network analysis. Our results suggest that administration of biotic agents as adjuvants are relevant for the prevention and/or treatment of the main diseases that affect female health, since they contribute to a healthy vaginal microbiota through anti-inflammatory and antimicrobial activities. Most clinical studies have demonstrated the effectiveness of intervention using probiotics to the detriment of other biotic agents in women's health, being bacterial vaginosis, polycystic ovary syndrome, and vulvovaginal candidiasis, the main diseases evaluated. However, preclinical studies have emphasized that the inhibition of pathogens responsible for the process of vaginal dysbiosis may be due to the formation of biofilm and the synthesis of compounds that could prevent the adhesion of these microorganisms. Future perspectives point to the beneficial modulation of the vaginal microbiota by biotic agents as a promising adjuvant approach to improve women's health.

A sterilization method for human decellularized vaginal matrices

Vaginal reconstruction is necessary for various congenital and acquired conditions, including vaginal aplasia, trauma, tumors, and gender incongruency. Current surgical and non-surgical treatments often result in significant complications. Decellularized vaginal matrices (DVMs) from human tissue offer a promising alternative, but require effective sterilization to ensure safety and functionality. This study aimed to develop a sterilization method for decellularized human vaginal wall scaffolds. Based on our previously implemented decellularization technique with minor modifications, we designed and examined three sterilization methods consisting of (i) chemical decellularization, (ii) decellularization with additional peracetic acid/hydrogen peroxide (PAA/H2O2); (iii) decellularization with antibiotic and antimycotic (AAE) based treatment. Sterilization efficacy was evaluated through controlled contamination with common vaginal microbes and sterility testing subsequent to each sterilization method. The extracellular matrix (ECM) structure was assessed via histological staining. Decellularization alone reduced some added bacterial contaminants but did not achieve complete sterilization. PAA/H2O2-sterilization resulted in severe ECM damage, rendering it unsuitable. The AAE-treatment demonstrated effective sterilization without compromising the ECM structure. Combined decellularization and AAE-based treatment forms a viable sterilization method for human vaginal wall tissue, maintaining ECM integrity and achieving effective micro-organism elimination. This method holds potential for clinical application in vaginal transplantation.

Vaginal Microbiome: Environmental, Biological, and Racial Influences on Gynecological Health Across the Lifespan

The human vaginal microbiome (VMB) is a complex and unique ecosystem composed of various microorganisms, including bacteria, fungi, archaea, viruses, and candidate phyla radiation. A healthy VMB is often characterized by the presence of Lactobacillus species, which play a crucial role in protecting and maintaining homeostasis within the vaginal environment. When this balance is disrupted, the protection of the vaginal epithelium weakens, leading to a reduction in Lactobacillus species and an increased risk of various gynecological and reproductive health issues. However, this generalized description can lead to misconceptions and an incomplete understanding of vaginal health, as Lactobacillus is not always dominant across all ages and racialized groups. Therefore, this review provides a comprehensive analysis of the environmental, biological, and racial influences on the VMB at each stage of a woman's life, highlighting their implications for gynecological health and offering a holistic understanding of the VMB for all women.

Assessment and Treatment of Vaginitis

Vaginitis is the presenting symptom at millions of office visits each year in the United States. Although treatment of sporadic cases is often straightforward, recurrent cases present both diagnostic and treatment challenges. Molecular diagnostic tests are likely superior to in-office microscopy for most clinicians and most cases. In both recurrent bacterial vaginosis and recurrent vulvovaginal candidiasis, national treatment guidelines recommend an extended treatment duration with one of the first-line agents. In cases in which such treatment is not successful, vaginal boric acid is likely the cheapest and easiest alternative option. New antifungal medications offer additional but limited treatment options. Probiotics are not recommended for prevention of vulvovaginal candidiasis; however, vaginal products containing Lactobacillus crispatus may have promise for recurrent bacterial vaginosis. Trichomoniasis should be treated with a 1-week course of metronidazole; this is the only sexually transmitted infection for which treatment recommendations vary by sex. In cases in which patients do not respond to initial treatment, the diagnosis should be reconsidered, and other potential causes such as desquamative inflammatory vaginitis, genitourinary syndrome of menopause, or vulvodynia should be considered.

"Gut" to grips with the science of the microbiome - a symposium report

The latest Yakult Science Study Day was held virtually on 2 November 2023. Aimed at healthcare professionals, researchers, and students, a variety of experts explored the latest gut microbiome research and what it means in practice. The morning sessions discussed the role of the microbiome in health and disease, the rapid advancements in DNA sequencing and implications for personalised nutrition, the current state of evidence on health benefits associated with fermented foods, prebiotics and probiotics and the challenges involved in interpreting research in this area. The afternoon session considered the emerging research on the microbiota-gut-brain axis in mediating effects of food on mood, the bidirectional impact of menopause on the gut microbiota, and the interplay between the gut and skin with implications for the treatment of rare and common skin disorders. The session ended with an update on the use of faecal microbiota transplant in both research and clinical practice. Undoubtedly, the gut microbiome is emerging as a key conductor of human health, both in relation to gastrointestinal and non-gastrointestinal outcomes. As research continues to elucidate mechanisms of action and confirm their effects in human trials, the gut microbiome should be a key consideration within a holistic approach to health moving forward.

Knowledge and perceptions of blood donors of the Western Cape Blood Services, South Africa, toward vaginal sample donation for biobanking

Introduction

Depletion of Lactobacillus species and an overgrowth of anaerobes in the vaginal tract bacterial vaginosis (BV)], is associated with non-optimal reproductive health outcomes, and increased susceptibility to sexually transmitted infections (STIs). BV is currently treated with antibiotics, although these provide suboptimal cure levels and high recurrence rates. Vaginal microbiota transplantation (VMT), the transfer of vaginal fluid from healthy donors with an optimal vaginal microbiota to a recipient with BV, has been proposed as an alternative treatment strategy.

Methods

Here, we investigated knowledge and perceptions of blood donors to the concept of an optimal vaginal microbiome and VMT via the Western Cape Blood Service (WCBS) clinics in Cape Town, South Africa, by a self-administered questionnaire.

Results & discussion

Analysis of responses from 106 eligible women showed that 86% (91/106) would consider donating samples. Responses significantly associated with willingness to donate vaginal samples included: (1) belief that helping others outweighs the inconvenience of donating vaginal sample (p = 1.093e-05) and (2) prior knowledge of the concept of a healthy vaginal microbiome (p = 0.001). Most potential donors (59/91; 65%) were willing to receive a VMT themselves if needed. Participants who were unwilling to donate vaginal samples (15/106; 14%) indicated that vaginal sample collection would be unpleasant and/or embarrassing. The benefits of a collaboration with WCBS for this project include the naturally altruistic nature of blood donors, the constant in-flow of donors to WCBS clinics, and the infrastructure and logistical aspects in place. Data from this observational study highlight factors affecting the willingness of blood donors to become vaginal sample donors.

Microbiological investigation of pregnancies following vaginal radical trachelectomy using 16S rRNA sequencing of FFPE placental specimens

This study examined the risk of intrauterine infection associated with radical trachelectomy (RT) in early-stage cervical cancer patients. This procedure preserves fertility but is linked to increased risk of intrauterine infection due to cervical defects during pregnancy. DNA was extracted from the formalin-fixed paraffin-embedded (FFPE) placental specimens of 23 pregnant post-RT patients and 16S rRNA gene sequencing was used for bacterial identification. The prevalence of Lactobacillus crispatus and Burkholderia stabilis was significantly higher in the non-chorioamnionitis group. In contrast, alpha diversity analysis using the PD index showed significantly higher diversity in the chorioamnionitis group (P = 0.04). The demonstrated relationship between chorioamnionitis and microbial diversity affirms the importance of controlling the genital bacterial flora in pregnancies following RT.

Unlocking the potential for microbiome-based therapeutics to address the sustainable development goal of good health and wellbeing

Recent years have witnessed major advances and an ever-growing list of healthcare applications for microbiome-based therapeutics. However, these advances have disproportionately targeted diseases common in high-income countries (HICs). Within low- to middle-income countries (LMIC), opportunities for microbiome-based therapeutics include sexual health epidemics, maternal health, early life mortality, malnutrition, vaccine response and infectious diseases. In this review we detail the advances that have been achieved in microbiome-based therapeutics for these areas of healthcare and identify where further work is required. Current efforts to characterise microbiomes from LMICs will aid in targeting and optimisation of therapeutics and preventative strategies specifically suited to the unmet needs within these populations. Once achieved, opportunities from disease treatment and improved treatment efficacy through to disease prevention and vector control can be effectively addressed using probiotics and live biotherapeutics. Together these strategies have the potential to increase individual health, overcome logistical challenges and reduce overall medical, individual, societal and economic costs.

Microbiota and Recurrent Pregnancy Loss (RPL); More than a Simple Connection

Recurrent Pregnancy Loss (RPL) affects 1-2% of women, and its triggering factors are unclear. Several studies have shown that the vaginal, endometrial, and gut microbiota may play a role in RPL. A decrease in the quantity of Lactobacillus crispatus in local microbiota has been associated with an increase in local (vaginal and endometrial) inflammatory response and immune cell activation that leads to pregnancy loss. The inflammatory response may be triggered by gram-negative bacteria, lipopolysaccharides (LPS), viral infections, mycosis, or atypia (tumor growth). Bacterial structures and metabolites produced by microbiota could be involved in immune cell modulation and may be responsible for immune cell activation and molecular mimicry. Gut microbiota metabolic products may increase the amount of circulating pro-inflammatory lymphocytes, which, in turn, will migrate into vaginal or endometrial tissues. Local pro-inflammatory Th1 and Th17 subpopulations and a decrease in local Treg and tolerogenic NK cells are accountable for the increase in pregnancy loss. Local microbiota may modulate the local inflammatory response, increasing pregnancy success. Analyzing local and gut microbiota may be necessary to characterize some RPL patients. Although oral supplementation of probiotics has not been shown to modify vaginal or endometrial microbiota, the metabolites produced by it may benefit patients. Lactobacillus crispatus transplantation into the vagina may enhance the required immune tolerogenic response to achieve a normal pregnancy. The effect of hormone stimulation and progesterone to maintain early pregnancy on microbiota has not been adequately studied, and more research is needed in this area. Well-designed clinical trials are required to ascertain the benefit of microbiota modulation in RPL.

The effectiveness of vaginal microbiota transplantation for vaginal dysbiosis and bacterial vaginosis: a scoping review

OBJECTIVE

To comprehensively summarize the existing evidence on the effectiveness of vaginal microbiota transplantation (VMT) in treating vaginal dysbiosis (VD) and bacterial vaginosis (BV).

METHODS

Following the PRISMA-ScR guidelines, a scoping review was conducted through October 10, 2023, using the databases PubMed, Embase, Scopus, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, SinoMed, Weipu (VIP), ClinicalTrials.gov and the Chinese clinical trial registry.

RESULTS

A total of 12 studies were included, of which 7 were published (comprising 3 human and 4 animal studies), and 5 were ongoing registered trials (human). Of the published human studies involving 36 women, one focused on VD, and two investigated BV. These studies reported that VMT restored the Lactobacillus-dominated vaginal microbiota, alleviating symptoms. In animal studies with 145 female rats or mice, VMT was explored for one case of VD and three cases of BV, demonstrating a reduction in the expression of IL-1β and TNF-α. Additionally, two of the animal studies also indicated an increase in the number of Lactobacilli following VMT. The ongoing registered trials involved 556 women, with two focusing on VD and three targeting BV.

CONCLUSIONS

VMT shows promise in restoring the Lactobacillus-dominated vaginal microbiota among women with VD or BV. Moreover, animal studies have indicated an increase in the number of Lactobacilli and a decrease in the expression of IL-1β and TNF-α following VMT. Ongoing registered trials are expected to provide comprehensive evidence regarding the efficacy of VMT.

Updates and Current Challenges in Reproductive Microbiome: A Comparative Analysis between Cows and Women

The microbiota plays an important role in numerous physiological processes, pathogenesis, development, and metabolism in different animal species. In humans, several studies have demonstrated an association between the vaginal microbiota and fertility rates, and even success in assisted reproduction techniques. In the context of cattle reproduction, although few studies have addressed the microbiota in a healthy state (which is not associated with diseases that affect the reproductive tract of cows), changes in its composition also seem to influence fertility. This review aims to explain the importance of the reproductive microbiota in female bovines and what is available in the literature regarding its possible role in increasing fertility. What are the challenges involved in this process? Future perspectives on its use and manipulation as a selection or intervention tool. Will it be possible to one day extrapolate the findings to reality and apply them in the field? In short, understanding the role of the reproductive microbiota of female bovines can signal the prospect of increasing production, whether of milk or meat, from the same number of animals, as it can optimize reproductive efficiency and perhaps become an allied tool for the economic profitability and sustainability of livestock farming.

The evolving facets of vaginal microbiota transplantation: reinvigorating the unexplored frontier amid complex challenges

In an age of cutting-edge sequencing methods and worldwide endeavors such as The Human Microbiome Project and MetaHIT, the human microbiome stands as a complex and diverse community of microorganisms. A central theme in current scientific inquiry revolves around reinstating a balanced microbial composition, referred to as "eubiosis," as a targeted approach for treating vast array of diseases. Vaginal Microbiota Transplantation (VMT), inspired by the success of fecal microbiota transplantation, emerges as an innovative therapy addressing vaginal dysbacteriosis by transferring the complete microbiota from a healthy donor. Antibiotics, while effective, pose challenges with adverse effects, high recurrence rates, and potential harm to beneficial Lactobacillus strains. Continued antibiotic usage also sparks worries regarding the development of resistant strains. Probiotics, though showing promise, exhibit inconsistency in treating multifactorial diseases, and concerns linger about their suitability for diverse genetic backgrounds. Given the recurrent challenges associated with antibiotic and probiotic treatments, VMT emerges as an imperative alternative, offering a unique and promising avenue for efficiently and reliably managing vaginal dysbiosis among a majority of women. This review critically evaluates findings from both animal and human studies, offering nuanced insights into the efficacy and challenges of VMT. An extensive analysis of clinical trials, provides a current overview of ongoing and completed trials, shedding light on the evolving clinical landscape and therapeutic potential of VMT. Delving into the origins, mechanisms, and optimized protocols of VMT, the review underscores the imperative for sustained research efforts to advance this groundbreaking gynecological therapy.

The microbiome in recurrent pregnancy loss - A scoping review

Recurrent pregnancy loss (RPL) is a troubling condition that affects couples worldwide. Despite extensive research efforts, many RPL cases remain unexplained, highlighting the need for novel approaches to unravel its underlying mechanisms. Recent advances in microbiome research have shed light on the potential role of the microbiome in reproductive health and outcomes. Based on a systematic literature research, this review aims to comprehensively explore the current understanding of the microbiome's involvement in RPL, focusing on the vaginal, endometrial, and gut microbiomes. Evidence from the available studies is examined to explain the relationship between the microbiome and RPL. Furthermore, we discuss the diagnostic potential of the microbiome, therapeutic interventions, and future directions in microbiome research for RPL. Understanding the complex interactions between the microbiome and reproductive health holds promise for developing targeted interventions to help patients today diagnosed as unexplained.

The endometrial microbiota and early pregnancy loss

The human endometrium is a dynamic entity that plays a pivotal role in mediating the complex interplay between the mother and developing embryo. Endometrial disruption can lead to pregnancy loss, impacting both maternal physical and psychological health. Recent research suggests that the endometrial microbiota may play a role in this, although the exact mechanisms are still being explored, aided by recent technological advancements and our growing understanding of host immune responses. Suboptimal or dysbiotic vaginal microbiota, characterized by increased microbial diversity and reduced Lactobacillus dominance, has been associated with various adverse reproductive events, including miscarriage. However, the mechanisms linking the lower reproductive tract microbiota with pregnancy loss remain unclear. Recent observational studies implicate a potential microbial continuum between the vaginal and endometrial niche in patients with pregnancy loss; however, transcervical sampling of the low biomass endometrium is highly prone to cross-contamination, which is often not controlled for. In this review, we explore emerging evidence supporting the theory that a dysbiotic endometrial microbiota may modulate key inflammatory pathways required for successful embryo implantation and pregnancy development. We also highlight that a greater understanding of the endometrial microbiota, its relationship with the local endometrial microenvironment, and potential interventions remain a focus for future research.

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.

Shaping Microbiota During the First 1000 Days of Life

Given that the host-microbe interaction is shaped by the immune system response, it is important to understand the key immune system-microbiota relationship during the period from conception to the first years of life. The present work summarizes the available evidence concerning human reproductive microbiota, and also, the microbial colonization during early life, focusing on the potential impact on infant development and health outcomes. Furthermore, we conclude that some dietary strategies including specific probiotics and other-biotics could become potentially valuable tools to modulate the maternal-neonatal microbiota during this early critical window of opportunity for targeted health outcomes throughout the entire lifespan.

Microbiota during pregnancy and early life: role in maternal-neonatal outcomes based on human evidence

Here, we explored the vast potential of microbiome-based interventions in preventing and managing non-communicable diseases including obesity, diabetes, allergies, celiac disease, inflammatory bowel diseases, malnutrition, and cardiovascular diseases across different life stages. We discuss the intricate relationship between microbiome and non-communicable diseases, emphasizing on the "window of opportunity" for microbe-host interactions during the first years after birth. Specific biotics and also live biotherapeutics including fecal microbiota transplantation emerge as pivotal tools for precision medicine, acknowledging the "one size doesn't' fit all" aspect. Challenges in implementation underscore the need for advanced technologies, scientific transparency, and public engagement. Future perspectives advocate for understanding maternal-neonatal microbiome, exploring the maternal exposome and delving into human milk's role in the establishment and restoration of the infant microbiome and its influence over health and disease. An integrated scientific approach, employing multi-omics and accounting for inter-individual variance in microbiome composition and function appears central to unleash the full potential of early-life microbiome interventions in revolutionizing healthcare.

Effect of L. crispatus M247 Administration on Pregnancy Outcomes in Women Undergoing IVF: A Controlled, Retrospective, Observational, and Open-Label Study

The aim of our study was to retrospectively evaluate whether the oral administration of L. crispatus (M247) could increase pregnancy and live birth rates in women undergoing assisted reproductive technology procedures. Enrolled women (N = 160) were divided into two groups: treated (N = 80) or untreated (N = 80) with the probiotic strain. The odds ratio (OR) for a treated woman to have a clinical pregnancy (CP) was 1.56. In women aged 30-40 years, M247 increased the probability of a CP in correlation with the progressive rise in BMI, reaching 47% (35% in controls) with a BMI of 35 (OR: 2.00). The CAID statistics showed that in a woman of the blastocyst subgroup, below 43 years, with a BMI over 18.6, treatment with M247 increased the chance of a CP from 28.4% to 44.5% (OR: 2.08; p < 0.05). Considering live births, the rate of the probiotic group was 12.5% versus 7.5% (OR: 1.76). Considering only the blastocyst subgroup, the treatment increased the number of live births by 200% (OR: 3.64; p = 0.05). As confirmed also by statistical indices NNT, NNH, and LHH, the use of M247 demonstrated a risk-benefit ratio to the full advantage of the benefits.

Emerging role of the host microbiome in neuropsychiatric disorders: overview and future directions

The human body harbors a diverse ecosystem of microorganisms, including bacteria, viruses, and fungi, collectively known as the microbiota. Current research is increasingly focusing on the potential association between the microbiota and various neuropsychiatric disorders. The microbiota resides in various parts of the body, such as the oral cavity, nasal passages, lungs, gut, skin, bladder, and vagina. The gut microbiota in the gastrointestinal tract has received particular attention due to its high abundance and its potential role in psychiatric and neurodegenerative disorders. However, the microbiota presents in other body tissues, though less abundant, also plays crucial role in immune system and human homeostasis, thus influencing the development and progression of neuropsychiatric disorders. For example, oral microbiota imbalance and associated periodontitis might increase the risk for neuropsychiatric disorders. Additionally, studies using the postmortem brain samples have detected the widespread presence of oral bacteria in the brains of patients with Alzheimer's disease. This article provides an overview of the emerging role of the host microbiota in neuropsychiatric disorders and discusses future directions, such as underlying biological mechanisms, reliable biomarkers associated with the host microbiota, and microbiota-targeted interventions, for research in this field.

New Insights into Photobiomodulation of the Vaginal Microbiome-A Critical Review

The development of new technologies such as sequencing has greatly enhanced our understanding of the human microbiome. The interactions between the human microbiome and the development of several diseases have been the subject of recent research. In-depth knowledge about the vaginal microbiome (VMB) has shown that dysbiosis is closely related to the development of gynecologic and obstetric disorders. To date, the progress in treating or modulating the VMB has lagged far behind research efforts. Photobiomodulation (PBM) uses low levels of light, usually red or near-infrared, to treat a diversity of conditions. Several studies have demonstrated that PBM can control the microbiome and improve the activity of the immune system. In recent years, increasing attention has been paid to the microbiome, mostly to the gut microbiome and its connections with many diseases, such as metabolic disorders, obesity, cardiovascular disorders, autoimmunity, and neurological disorders. The applicability of PBM therapeutics to treat gut dysbiosis has been studied, with promising results. The possible cellular and molecular effects of PBM on the vaginal microbiome constitute a theoretical and promising field that is starting to take its first steps. In this review, we will discuss the potential mechanisms and effects of photobiomodulation in the VMB.

NK and T Cell Subtypes in the Endometrium of Patients with Recurrent Pregnancy Loss and Recurrent Implantation Failure: Implications for Pregnancy Success

BACKGROUND

RPL and RIF are challenges in reproductive medicine. The immune system plays a pivotal role in endometrial receptivity, successful implantation, and pregnancy complications. Immunological changes have been associated with RPL and RIF. Understanding immune dysregulation especially in NK and T cell subtypes may lead to better diagnostic concepts and treatments. From July 2019 to August 2020 patients with RPL and RIF underwent a standardized diagnostic procedure including endometrial biopsies. Immune cell analysis was performed using flow cytometry. Patients were contacted in March 2023 and interviewed concerning their pregnancy outcomes following diagnostics.

RESULTS

Out of 68 patients undergoing endometrial biopsies, 49 patients were finally included. Live birth rates were high with 72% in RPL and 86% in RIF. Immune cell analysis revealed that patients with RPL had more cytotoxic CD56dimCD16high cells, while RIF patients had more CD56+ uNK cells. RPL patients with pregnancy complications showed increased NKT cell percentages.

CONCLUSION

Our findings suggest specific immune changes in RPL and RIF patients, offering potential therapeutic targets. Tailored immunotherapy based on endometrial immunophenotyping might be an option, but further research is needed.