Systematic Review and Meta-analysis: Changes of Gut Microbiota before and after Menopause

Characterization of the vaginal microbiota in Italian women with endometriosis: preliminary study

PURPOSE

This cross-sectional study aims to assess the interplay between the vaginal microbiota and endometriosis.

METHODS

123 consecutive Italian fertile women, aged between 20 and 40 years old, were enrolled during a routine gynecological consultation; 24 were diagnosed with endometriosis and 99 did not complain of any gynecological disease. All women underwent a vaginal swab for the evaluation of the composition and diversity of vaginal microbiota by means of 16 s rDNA metagenomic sequencing.

RESULTS

Compared to women with no gynecological disease, the vaginal microbiota in women with endometriosis showed a similar abundance of Lactobacillus spp.; however, a statistically significant lower abundance in the genera Pseudomonas (p < 0.01), Bifidobacterium (p < 0.05), Novispirillum (p < 0.0000001) and Sphingomonas (p < 0.0000001), and a statistically significant increase in the abundance of the genera Escherichia (p < 0.00001), Megasphaera (p < 0.00001), and Sneathia (p < 0.0001) were observed.

CONCLUSIONS

There is a complex interplay between vaginal microbiota composition and endometriosis, showing a distinct microbial signature in the bacterial genera usually found in dysbiosis.

Sex Differences in Cardiovascular Diseases: Exploring the Role of Microbiota and Immunity

Cardiovascular diseases (CVDs) are the most common cause of mortality and morbidity in Western countries, thus representing a global health concern. CVDs show different patterns in terms of the prevalence and presentation in men and women. The role of sex hormones has been extensively implicated in these sex-specific differences, due to the presence of the menstrual cycle and menopause in women. Moreover, the gut microbiota (GM) has been implicated in cardiovascular health, considering the growing evidence that it is involved in determining the development of specific diseases. In particular, gut-derived metabolites have been linked to CVDs and kidney disorders, which can in turn promote the progression of CVDs. Considering the differences in the composition of GM between men and women, it is possible that gut microbiota act as a mediator in regard to the sex disparities in CVDs. This narrative review aims to comprehensively review the interplay between sex, GM, and CVDs, discussing potential mechanisms and therapeutic options.

Postmenopausal endometriosis: a challenging condition beyond menopause

IMPORTANCE AND OBJECTIVE

Postmenopausal endometriosis is a complex condition that challenges the conventional belief that endometriosis resolves with menopause. Despite the cessation of menstruation, a subset of women continues to experience or develop endometriosis-related symptoms during the postmenopausal period. Thus, this review aimed to shed light on postmenopausal endometriosis, exploring its clinical features, diagnostic considerations, management approaches, and the potential impact on women's health.

METHODS

PubMed/Medline, Scopus, and Web of Science databases were used for the research, with only articles in English language, using the following terms: "postmenopausal endometriosis," "menopause," "management," "treatment," and "quality of life," from inception to 2023.

DISCUSSION AND CONCLUSION

The clinical features of postmenopausal endometriosis include persistent or recurrent pelvic pain, dyspareunia, bowel, or urinary symptoms and, occasionally, abnormal vaginal bleeding. The absence of menstrual cycles presents a diagnostic challenge, as the traditional diagnostic criteria for endometriosis rely on menstrual patterns. Visual cues may be less evident, and the symptoms often overlap with other gynecological conditions, necessitating a thorough evaluation to differentiate postmenopausal endometriosis from other potential causes. Management approaches for postmenopausal endometriosis encompass surgical intervention, hormonal therapies, pain management, and individualized care. Postmenopausal endometriosis significantly impacts the quality of life, sexual health, and long-term well-being of women. Understanding the clinical features, diagnostic challenges, and management approaches of postmenopausal endometriosis is crucial for healthcare professionals to provide effective care and to improve the quality of life of women affected by this condition.

Effects of mind-body exercise on perimenopausal and postmenopausal women: a systematic review and meta-analysis

IMPORTANCE

The increasing attention to the management of perimenopausal and postmenopausal women parallels the growth of the aging population. Although hormone therapy is commonly used to alleviate menopausal symptoms, it carries a potential risk of cancer. Recently, mind-body exercises have emerged as innovative approaches for improving menopausal symptoms and bone health. However, research findings have needed to be more consistent, highlighting the significance of this study's systematic review of mind-body exercise effects on perimenopausal and postmenopausal women.

OBJECTIVE

This study aims to evaluate the impact of mind-body exercises, including tai chi, yoga, Pilates, qigong, baduanjin, and mindfulness-based stress reduction, on bone mineral density, sleep quality, anxiety, depression, and fatigue among perimenopausal and postmenopausal women.

EVIDENCE REVIEW

Four electronic databases-PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science-were systematically searched from inception until July 2023. The search focused exclusively on randomized controlled trials to examine the impact of mind-body exercise interventions on perimenopausal and postmenopausal women. The methodological quality of the included studies was evaluated using the Cochrane Bias Risk Assessment tool.

FINDINGS

A total of 11 randomized controlled trials, comprising 1,005 participants, were included in the analysis. Traditional meta-analysis indicated that mind-body exercise significantly enhanced bone mineral density in perimenopausal and postmenopausal women compared with control groups, with a standardized mean difference (SMD) of 0.41 (95% CI, 0.17 to 0.66; P = 0.001, I2 = 7%). In addition, significant improvements were observed in sleep quality (SMD, -0.48; 95% CI, -0.78 to -0.17; P = 0.002, I2 = 76%), anxiety reduction (SMD, -0.80; 95% CI, -1.23 to -0.38; P = 0.0002, I2 = 84%), depressive mood (SMD, -0.80; 95% CI, -1.17 to -0.44; P < 0.0001, I2 = 79%), and fatigue (SMD, -0.67; 95% CI, -0.97 to -0.37; P < 0.0001, I2 = 0%).

CONCLUSIONS AND RELEVANCE

The findings of this meta-analysis demonstrate that mind-body exercise positively influences bone mineral density, sleep quality, anxiety, depression, and fatigue among perimenopausal and postmenopausal women.

Oral Milk-Derived Extracellular Vesicles Inhibit Osteoclastogenesis and Ameliorate Bone Loss in Ovariectomized Mice by Improving Gut Microbiota

Milk-derived extracellular vesicles can improve intestinal health and have antiosteoporosis potential. In this paper, we explored the effects of bovine raw milk-derived extracellular vesicles (mEVs) on ovariectomized (OVX) osteoporotic mice from the perspective of the gut-bone axis. mEVs could inhibit osteoclast differentiation and improve microarchitecture. The level of osteoporotic biomarkers in OVX mice was restored after the mEVs intervened. Compared with OVX mice, mEVs could enhance intestinal permeability, reduce endotoxin levels, and improve the expression of TNF-α, IL-17, and IL-10. 16S rDNA sequencing indicated that mEVs altered the composition of gut microbiota, specifically for Bacteroides associated with short-chain fatty acids (SCFAs). In-depth analysis of SCFAs demonstrated that mEVs could restore acetic acid, propionic acid, valeric acid, and isovaleric acid levels in OVX mice. Correlation analysis revealed that changed gut microbiota and SCFAs were significantly associated with gut inflammation and osteoporotic biomarkers. This study demonstrated that mEVs could inhibit osteoclast differentiation and improve osteoporosis by reshaping the gut microbiota, increasing SCFAs, and decreasing the level of pro-inflammatory cytokines and osteoclast differentiation-related factors in OVX mice. These findings provide evidence for the use of mEVs as a food supplement for osteoporosis.

Functional hypothalamic amenorrhea: gut microbiota composition and the effects of exogenous estrogen administration

Functional hypothalamic amenorrhea (FHA) is characterized by estrogen deficiency that significantly impacts metabolic, bone, cardiovascular, mental, and reproductive health. Given the importance of environmental factors such as stress and body composition, and particularly considering the importance of estrogens in regulating the gut microbiota, some changes in the intestinal microenvironment are expected when all of these factors occur simultaneously. We aimed to assess whether the gut microbiota composition is altered in FHA and to determine the potential impact of hormonal replacement therapy (HRT) on the gut microbiota. This prospective observational study included 33 patients aged 18-34 yr with FHA and 10 age-matched healthy control women. Clinical, hormonal, and metabolic evaluations were performed at baseline for the FHA group only, whereas gut microbiota profile was assessed by 16S rRNA gene amplicon sequencing for both groups. All measurements were repeated in patients with FHA after receiving HRT for 6 mo. Gut microbiota alpha diversity at baseline was significantly different between patients with FHA and healthy controls (P < 0.01). At the phylum level, the relative abundance of Fusobacteria was higher in patients with FHA after HRT (P < 0.01), as was that of Ruminococcus and Eubacterium at the genus level (P < 0.05), which correlated with a decrease in circulating proinflammatory cytokines. FHA is a multidimensional disorder that is interconnected with dysbiosis through various mechanisms, particularly involving the gut-brain axis. HRT appears to induce a favorable shift in the gut microbiota in patients with FHA, which is also associated with a reduction in the systemic inflammatory status.NEW & NOTEWORTHY Our study marks the first comprehensive analysis of gut microbiota composition in FHA and the impact of HRT on it, along with biochemical, anthropometric, and psychometric aspects. Our results indicate distinct gut microbiota composition in patients with FHA compared with healthy individuals. Importantly, HRT prompts a transition toward a more beneficial gut microbiota profile and reduced inflammation. This study validates the concept of FHA as a multifaceted disorder interlinked with dysbiosis, particularly involving the gut-brain axis.

The influence of the gut microbiome on ovarian aging

Ovarian aging occurs prior to the aging of other organ systems and acts as the pacemaker of the aging process of multiple organs. As life expectancy has increased, preventing ovarian aging has become an essential goal for promoting extended reproductive function and improving bone and genitourinary conditions related to ovarian aging in women. An improved understanding of ovarian aging may ultimately provide tools for the prediction and mitigation of this process. Recent studies have suggested a connection between ovarian aging and the gut microbiota, and alterations in the composition and functional profile of the gut microbiota have profound consequences on ovarian function. The interaction between the gut microbiota and the ovaries is bidirectional. In this review, we examine current knowledge on ovary-gut microbiota crosstalk and further discuss the potential role of gut microbiota in anti-aging interventions. Microbiota-based manipulation is an appealing approach that may offer new therapeutic strategies to delay or reverse ovarian aging.

Association of probiotic ingestion with serum sex steroid hormones among pre- and postmenopausal women from the NHANES, 2013-2016

BACKGROUND

Sex hormone-related diseases, encompassing a wide range of conditions from reproductive disorders to certain cancers, pose significant health challenges worldwide. Recent scientific investigations have highlighted the intricate interplay between the gut microbiome and sex hormone regulation, indicating the potential for microbiota-targeted interventions in the management of such diseases. Although individual studies have elucidated the influence of the gut microbiome on sex hormones, a comprehensive cross-sectional examination of the population-wide prevalence of probiotic intake and its correlation with sex hormones is still lacking.

OBJECTIVES

This study aimed to evaluate the association of probiotic ingestion with sex hormones in pre- and post-menopausal women.

METHODS

We conducted an observational cohort study comprising a nationally representative sample of adults who participated in the National Health and Nutrition Examination Survey between 2013 and 2016. Probiotic ingestion was considered when a subject reported yogurt or probiotic supplement consumption during the 24-h dietary recall or during the Dietary Supplement Use 30-Day questionnaire. A survey-weighted generalized linear model was used to analyze the association between probiotic intake and female/male sex hormones. To reduce selection bias, we used propensity score matching (PSM).

RESULTS

This study included 2,699 women, with 537 of them consuming yogurt and/or dietary supplements containing probiotics, while the remaining 2,162 women did not consume any probiotics. The findings indicated that there were associations between probiotic intake and sex hormone levels in premenopausal and postmenopausal women. For premenopausal women, probiotic intake was positively associated with estradiol (E2) levels. On the contrary, in postmenopausal women, probiotic intake was inversely associated with total testosterone (TT) levels.

CONCLUSIONS

This study indicated that probiotic consumption was associated with higher E2 level in premenopausal women and lower TT level in postmenopausal women. Probiotic intake might be a sensible strategy for preventing sex hormone-related diseases.

Exploring the role of gut microbiota in autoimmune thyroid disorders: a systematic review and meta-analysis

Background

Autoimmune thyroid diseases (AITDs) are characterized by unique immune responses against thyroid antigens and persist over time. The most common types of AITDs are Graves' disease (GD) and Hashimoto's thyroiditis (HT). There is mounting evidence that changes in the microbiota may play a role in the onset and development of AITDs.

Objective

The purpose of this comprehensive literature study was to answer the following query: Is there a difference in microbiota in those who have AITDs?

Methods

According to the standards set out by the PRISMA statement, 16 studies met the requirements for inclusion after being screened for eligibility.

Results

The Simpson index was the only diversity measure shown to be considerably lower in patients with GD compared to healthy participants, whereas all other indices were found to be significantly greater in patients with HT. The latter group, however, showed a greater relative abundance of Bacteroidetes and Actinobacteria at the phylum level, and consequently of Prevotella and Bifidobacterium at the genus level. The strongest positive and negative relationships were seen for thyroid peroxidase antibodies and bacterial load.

Conclusion

Overall, both GD and HT patients showed significant changes in the gut microbiota's diversity and composition.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023432455.

Phytosterols Protect against Osteoporosis by Regulating Gut Microbiota

Osteoporosis is increasingly prevalent worldwide, representing a major health burden. However, there is a lack of nutritional strategies for osteoporotic therapy. Phytosterols, as natural bioactive compounds, have the potential to alleviate osteoporosis. In this study, a glucocorticoid-induced osteoporosis mouse model and treatment with low and high concentrations of phytosterols for 4 weeks were established. The results demonstrated that compared to the control group, low-concentration phytosterols (LP) (0.3 mg/mL) increased bone mass, improved trabecular microstructure, reduced serum levels of cross-linked C-telopeptide of type I collagen (CTX-1), and elevated serum levels of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). Conversely, high-concentration phytosterols (0.5 mg/mL) showed no effect. Additionally, we validated the effect of LP in ameliorating osteoporosis using an ovariectomized (OVX)-induced osteoporosis mouse model. Mechanistically, phytosterols altered the microbial composition to counteract glucocorticoid-induced gut microbiota disorder and improve the length and morphology of the small intestine. Particularly, based on selection strategy and correlation analysis, phytosterols increased the relative abundance of Ruminococcus and decreased the relative abundance of Bilophila, which were significantly associated with glucocorticoid-induced osteoporosis indications. Overall, these findings suggest that phytosterols regulate gut microbiota to increase bone mass, thereby exerting an antiosteoporotic effect.

Altered gut microbiota profile in patients with perimenopausal panic disorder

Introduction

Females in the perimenopausal period are susceptible to mood disorders. Perimenopausal panic disorder (PPD) is characterized by repeated and unpredictable panic attacks during perimenopause, and it impacts the patient's physical and mental health and social function. Pharmacotherapy is limited in the clinic, and its pathological mechanism is unclear. Recent studies have demonstrated that gut microbiota is strongly linked to emotion; however, the relation between PPD and microbiota is limitedly known.

Methods

This study aimed to discover specific microbiota in PPD patients and the intrinsic connection between them. Gut microbiota was analyzed in PPD patients (n = 40) and healthy controls (n = 40) by 16S rRNA sequencing.

Results

The results showed reduced α-diversity (richness) in the gut microbiota of PPD patients. β-diversity indicated that PPD and healthy controls had different intestinal microbiota compositions. At the genus level, 30 species of microbiota abundance had significantly different between the PPD and healthy controls. In addition, HAMA, PDSS, and PASS scales were collected in two groups. It was found that Bacteroides and Alistipes were positively correlated with PASS, PDSS, and HAMA.

Discussion

Bacteroides and Alistipes dysbiosis dominate imbalanced microbiota in PPD patients. This microbial alteration may be a potential pathogenesis and physio-pathological feature of PPD. The distinct gut microbiota can be a potential diagnostic marker and a new therapeutic target for PPD.

Microbiota Alterations in Patients with Autoimmune Thyroid Diseases: A Systematic Review

Autoimmune thyroid diseases (AITDs) are chronic autoimmune disorders that cause impaired immunoregulation, leading to specific immune responses against thyroid antigens. Graves' disease (GD) and Hashimoto's thyroiditis (HT) are the major forms of AITDs. Increasing evidence suggests a possible role of microbiota alterations in the pathogenesis and progression of AITDs. This systematic review was designed to address the following question: "Is microbiota altered in patients with AITDs?" After screening the selected studies using the inclusion and exclusion criteria, 16 studies were included in this review (in accordance with PRISMA statement guidelines). A meta-analysis revealed that patients with HT showed significantly higher values of diversity indices (except for the Simpson index) and that patients with GD showed significant tendencies toward lower values of all assessed indices compared with healthy subjects. However, the latter demonstrated a higher relative abundance of Bacteroidetes and Actinobacteria at the phylum level and thus Prevotella and Bifidobacterium at the genus level, respectively. Thyroid peroxidase antibodies showed the most significant positive and negative correlations between bacterial levels and thyroid functional parameters. In conclusion, significant alterations in the diversity and composition of the intestinal microbiota were observed in both GD and HT patients.