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Lack of association between endocrine disrupting chemicals and male fertility: A systematic review and meta-analysis.
Martínez, MÁ, Marquès, M, Salas-Huetos, A, Babio, N, Domingo, JL, Salas-Salvadó, J
Environmental research. 2023;217:114942
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Exposure to natural or synthetic chemicals is directly related to environmental conditions, dietary and other lifestyle factors. Some of these chemicals are named endocrine disrupting chemicals (EDCs) because of their capability to interfere with the endocrine system. The aim of this study was to summarise and explore the association between exposure to EDCs and human male fertility indicators. This study is a systematic review and meta-analysis of seven studies; 4 assessed bisphenol A (BPA) in urine and sperm quality parameters, while 3 articles evaluated PCB153 [polychlorinated biphenyls] in serum and sperm quality parameters. Results show that there weren’t any positive or inverse associations between BPA or PCB153 and the sperm parameters analysed. Authors conclude that the systematic review showed a high disparity between studies, making difficult a consensus on the possible detrimental effect of the 12 groups of EDCs on male fertility. Thus, no conclusive statements can be drawn. Further studies are needed in order to provide more robust data.
Abstract
The incidence of infertility currently affects about 15% of the world's population. Male factors are estimated to be responsible for up to 40-50% of these cases. While the cause of these reproductive disorders is still unclear, the exposure to a family of ubiquitous compounds in our daily life, named endocrine disrupting chemicals (EDCs) could be involved. This paper was aimed at performing a systematic review and meta-analysis of population studies exploring whether human male exposure to EDCs affects male fertility. Clinical and observational studies assessing the exposure to EDCs along with sperm quality, the most common reproductive disorders, sperm DNA damage, sperm oxidative stress, fertilization rate, implantation rate, clinical pregnancy rate, live birth rate, and miscarriage rate were included. The quality assessment tool from the NHLBI-NIH was used to assure that studies met standardized quality criteria. Sensitivity analysis and heterogeneity among studies was assessed. Overall, the 32 selected articles, including 7825 individuals in the systematic review, explored 12 families of EDCs. The results revealed a high heterogeneity among studies in relation to the association between exposure to EDCs and the endpoints analyzed. Meta-analyses were performed with data from 7 articles including 479 individuals, 4 articles assessing the association between BPA in urine and sperm quality, and 3 articles evaluating PCB153 in serum and sperm quality. In the meta-analysis, we identified an unpredicted significant positive association between PCB153 exposure and sperm concentration. However, it would not be clinically relevant. No positive or inverse associations were found neither for BPA, nor for PCB153 and the rest of sperm parameters analyzed. The high disparity between studies made difficult to draw conclusions on the potential harmful effects of EDCs on male fertility. Consequently, to delineate the potential relationship that EDCs can have on male fertility, an important condition stressing the health system, further investigations are required.
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Lifestyle-, environmental-, and additional health factors associated with an increased sperm DNA fragmentation: a systematic review and meta-analysis.
Szabó, A, Váncsa, S, Hegyi, P, Váradi, A, Forintos, A, Filipov, T, Ács, J, Ács, N, Szarvas, T, Nyirády, P, et al
Reproductive biology and endocrinology : RB&E. 2023;21(1):5
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The World Health Organization defines infertility as regular unprotected sexual intercourse without achieving conception within a year. In recent years, there has been a growing demand for functional, objective parameters reflecting fertility status more clearly than classical parameters. Of these, sperm DNA fragmentation (SDF) and the DNA fragmentation index – denoting the percentage of sperm with damaged DNA – seem to be of utmost importance. The aim of this study was to investigate all risk factors that may potentially be increasing SDF. This study is a systematic review and meta-analysis of one hundred and ninety articles. The earliest studies were published in 2003, and the latest in 2021. Results show that several modifiable risk factors negatively affect SDF, namely; a. health conditions: varicocele [when veins become enlarged inside the pouch of skin that holds the testicles] and impaired glucose tolerance, b. infections: Chlamydia, c. malignancies: testicular tumours, and d. lifestyle factors: smoking, alcohol consumption and body mass index. Authors conclude that several lifestyle-, environmental-, and additional health factors are associated with increased SDF.
Abstract
INTRODUCTION Infertility affects one in every six couples in developed countries, and approximately 50% is of male origin. In 2021, sperm DNA fragmentation (SDF) testing became an evidence-based test for fertility evaluations depicting fertility more clearly than standard semen parameters. Therefore, we aimed to summarize the potential prognostic factors of a higher SDF. METHODS We conducted a systematic search in three medical databases and included studies investigating any risk factors for SDF values. We calculated mean differences (MD) in SDF with 95% confidence interval (CI) for exposed and non-exposed individuals. RESULTS We included 190 studies in our analysis. In the group of associated health conditions, varicocele (MD = 13.62%, CI: 9.39-17.84) and impaired glucose tolerance (MD = 13.75%, CI: 6.99-20.51) had the most significant increase in SDF. Among malignancies, testicular tumors had the highest impact, with a maximum of MD = 11.3% (CI: 7.84-14.76). Among infections, the overall effects of both Chlamydia and HPV were negligible. Of lifestyle factors, smoking had the most disruptive effect on SDF - an increase of 9.19% (CI: 4.33-14.06). Different periods of sexual abstinence did not show significant variations in SDF values. Age seemed to have a more drastic effect on SDF from age 50 onwards, with a mean difference of 12.58% (CI: 7.31-17.86). Pollution also had a detrimental effect - 9.68% (CI: 6.85-12.52). CONCLUSION Of the above risk factors, varicocele, impaired glucose tolerance, testicular tumors, smoking, pollution, and paternal age of over 50 were associated with the highest SDF. TRIAL REGISTRATION CRD42021282533.
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Effects of mild/asymptomatic COVID-19 on semen parameters and sex-related hormone levels in men: a systematic review and meta-analysis.
Che, BW, Chen, P, Yu, Y, Li, W, Huang, T, Zhang, WJ, Xu, SH, He, J, Liu, M, Tang, KF
Asian journal of andrology. 2023;25(3):382-388
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Various studies have shown that coronavirus disease 2019 (COVID-19) can cause more harm and a higher mortality rate to men. However, the literature does not clearly show that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause serious and lasting damage to male reproductive function. The aims of this study were to explore the effects of mild/asymptomatic COVID-19 on semen parameters and sex-related hormone levels and to analyse the relationship between semen parameter values and semen collection time after infection, fever, and severity of COVID-19. This study is a systematic review and meta-analysis of thirteen studies of which only five were included in the meta-analysis. Results show that COVID-19 has a certain effect on male reproductive function in the short term especially within about 70 days after infection. Additionally, fever after infection only had a significant effect on sperm concentration. Authors conclude by recommending the avoidance of pregnancy for a short period of time when the male partner has been infected with COVID-19.
Abstract
Coronavirus disease 2019 (COVID-19) has yet to be proven to alter male reproductive function, particularly in the majority of mild/asymptomatic patients. The purpose of this study was to explore whether mild/asymptomatic COVID-19 affects semen quality and sex-related hormone levels. To find suitable comparative studies, a systematic review and meta-analysis was done up to January 22, 2022, by using multiple databases (Web of Science, PubMed, and Embase). Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to identify and choose the studies. Meta-analysis was used to examine the semen parameters and sex-related hormones of mild/asymptomatic COVID-19 patients before and after infection. The effects of semen collection time, fever, and intensity of verification on semen following infection were also investigated. A total of 13 studies (n = 770) were included in the analysis, including three case-control studies, six pre-post studies, and four single-arm studies. A meta-analysis of five pre-post studies showed that after infection with COVID-19, sperm concentration (I2 = 0; P = 0.003), total sperm count (I2 = 46.3%; P = 0.043), progressive motility (I2 = 50.0%; P < 0.001), total sperm motility (I2 = 76.1%; P = 0.047), and normal sperm morphology (I2 = 0; P = 0.001) decreased. Simultaneously, a systematic review of 13 studies found a significant relationship between semen collection time after infection, inflammation severity, and semen parameter values, with fever having only bearing on semen concentration. Furthermore, there was no significant difference in sex-related hormone levels before and after infection in mild/asymptomatic patients. Mild/asymptomatic COVID-19 infection had a significant effect on semen quality in the short term. It is recommended to avoid initiating a pregnancy during this period of time.
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Mycotoxin-Linked Mutations and Cancer Risk: A Global Health Issue.
Ekwomadu, T, Mwanza, M, Musekiwa, A
International journal of environmental research and public health. 2022;19(13)
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Mycotoxins are toxic substances produced by fungi, which can be found in common foods like maize, wheat, nuts, and foods containing them. Mycotoxins such as aflatoxins, ochratoxin, fumonisins, zearalenone, and some Penicillium toxins can alter genetic material. According to previous studies, they can damage genetic material and affect cell growth. Usage of chemicals such as fertilizers and fungicides is a common practice in the agricultural industry to protect plants from fungus and to feed them. However, fungicides can accelerate mycotoxin production. 16 studies were included in this Systematic Review and 11 in Meta-Analysis. This research looked at the harmful effects of mycotoxins such as aflatoxins, fumonisins, ochratoxin, T2, zearalenone, and some Penicillium toxins in causing cancers. The researchers evaluated the link between aflatoxin exposure and liver cancer, fumonisin B1 exposure and liver cancer, zearalenone exposure and breast cancer, zearalenone exposure and cervical cancer, citrinine and patulin exposure and colorectal cancer, and NEO, HT-2, and T-2 exposure and Oesophageal cancer. This research did not show significant associations between various mycotoxins and cancer risk. As currently, most studies are primarily focused on aflatoxin; more robust studies are needed to assess the cancer risk associated with different mycotoxin exposure. Using the results of this study, healthcare professionals can gain a better understanding of how mycotoxins affect our bodies.
Abstract
Humans continue to be constantly exposed to mycotoxins, mainly through oral exposure (dietary), inhalation, or dermal contact. Recently, it has been of increasing interest to investigate mycotoxin-linked carcinogenicity. This systematic review was conducted to synthesize evidence of the association between mycotoxin-linked mutations and the risk of cancer, to provide an overview of the data linking exposure to different mycotoxins with human cancer risk, and to provide an update on current research on the risk of cancer associated with human exposure to mycotoxins. PRISMA guidelines were used when conducting the systematic review. PubMed, MEDLINE, and CINAHL electronic databases were comprehensively searched to extract the relevant studies published from inception to May 2022. A total of sixteen relevant studies (4907 participants) were identified and included in this review. Of these, twelve studies were from Asia, while four of the studies were conducted in Africa. The overall meta-analysis result found no significant association, although some of the studies confirmed an association between mycotoxin-linked mutations and primary liver cancer risk. Mainly, the experimental studies have shown associations between mycotoxin-linked mutations and cancer risk, and there is a need for researchers to confirm these links in epidemiological studies in order to guide public health policies and interventions.
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The impact of diabetes mellitus type 1 on male fertility: Systematic review and meta-analysis.
Facondo, P, Di Lodovico, E, Delbarba, A, Anelli, V, Pezzaioli, LC, Filippini, E, Cappelli, C, Corona, G, Ferlin, A
Andrology. 2022;10(3):426-440
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The relationship between type 2 diabetes mellitus and male hypogonadism is well known, whereas the impact of type 1 diabetes mellitus (DM1) on male fertility and testis functions has been less studied. The aim of this study was to systematically review and discuss the available evidence evaluating paternity rate, male gonadal axis, and sperm parameters in men with DM1. This study is a systematic review and meta-analysis of fourteen studies. Results show: - reduced fertility potential in patients with DM1, as they have a lower number of children compared with unaffected population. In fact, the rate of children is statistically significantly lower among men who had been diagnosed with DM1 at an earlier age, according to a longer duration of the disease. - that men with DM1, compared with controls, have significantly lower normal sperm morphology, progressive motility and a trend toward a reduced semen volume, without difference in total sperm count and concentration. Authors conclude that DM1 might impair reproductive health at different levels, including functional sperm alterations definitively leading to reduced fertility rate in these patients.
Abstract
BACKGROUND Some evidence suggests that diabetes mellitus type 1 (DM1) could affect male fertility, gonadal axis, semen parameters, and spermatogenesis because of effects of hyperglycemia and insulin deficiency. Anyhow, the exact impact of DM1 on male fertility is unclear. OBJECTIVES To review the studies evaluating paternity rate, male gonadal axis, and semen parameters in men with DM1. MATERIALS AND METHODS A review of relevant literature from January 1980 to December 2020 was performed. Only studies published in English reporting data on fatherhood (rate of children by natural fertility), hormonal and seminal parameters were included. Out of 14 retrieved articles, the eight studies evaluating semen parameters were meta-analyzed. RESULTS The rate of children (four studies) was lower than controls among men affected by DM1, especially in men with a longer duration of disease. The data of gonadal hormonal profile in DM1 men (six studies) are very heterogeneous and a neutral effect of DM1 or a condition of subclinical hypogonadism could not be concluded. Meta-analysis showed that men with DM1 (n = 380), compared with controls (n = 434), have significantly lower normal sperm morphology [-0.36% (-0.66; -0.06), p < 0.05, six studies] and sperm progressive motility [33.62% (-39.13; -28.11), p < 0.001, two studies] and a trend toward a lower seminal volume [-0.51 (-1.03; 0.02), p = 0.06, eight studies], without difference in total sperm count and concentration. Data on scrotal ultrasound and sperm DNA fragmentation are too few. No study evaluated other factors of male infertility, such as transrectal ultrasound, semen infections, sperm auto-antibodies, and retrograde ejaculation. DISCUSSION DM1 might impair male fertility and testis functions (endocrine, spermatogenesis), but definition of its actual impact needs further studies. CONCLUSION Men with DM1 should be evaluated with a complete hormonal, seminal, and ultrasound workup to better define their fertility potential and need for follow up of testis functions.
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The effect of healthy dietary patterns on male semen quality: a systematic review and meta-analysis.
Cao, LL, Chang, JJ, Wang, SJ, Li, YH, Yuan, MY, Wang, GF, Su, PY
Asian journal of andrology. 2022;24(5):549-557
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Infertility has been identified by the World Health Organization as a worldwide problem. The analysis of semen quality is key in assessing male fertility. The aim of this study was to explore the effect of healthy dietary patterns on male semen quality. This study is a systematic review and meta-analysis of six articles. The six articles were cross-sectional studies involving 1244 subjects, however, 708 subjects with the lowest and highest adherence to a healthy dietary pattern were included in the meta-analysis. Results show that the sperm concentration, progressive sperm motility, and total sperm count were significantly higher in the group with high consumption of a healthy dietary pattern than those in the group with low consumption; however, there wasn’t a clear relationship between normal sperm morphology, total sperm motility, and semen volume. Authors conclude that dietary interventions should be considered in clinical work as part of the therapies improving male semen quality.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This Systematic Review and Meta Analysis showed that healthy dietary patterns had beneficial effects on sperm concentration, total sperm count, and progressive sperm motility in males, which affect male fertility.
- Authors concluded that healthy dietary patterns may promote male reproductive health and thus improve semen quality in the population.
- Healthy dietary patterns meant the Mediterranean diet for 4 out of 6 studies. All healthy diet patterns were determined by the authors to be rich in plant-based foods, where saturated fats provide only a small percentage of the total energy intake.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
- This study aimed to determine the effects of healthy dietary patterns on semen quality.
Methodology
- This meta-analysis was performed following PRISMA guidelines and included 6 cross-sectional studies with 1244 participants
- The included cross-sectional studies examined the influence of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and prudent diet patterns on semen quality parameters.
- In 4 of the studies participants were divided into groups based on their scores for the Mediterranean diet from low to high adherence.
- 2 studies examined the DASH diet and the prudent diet and used food frequency questionnaires to compare high consumption with low consumption of healthy dietary patterns.
- The PICOS (Participants, Intervention, Comparison, Outcomes, and Study design) criteria that were used to structure the research question.
- 11 Checklists were used to assess the quality of included studies.
Results:
By comparing high consumption with low consumption of healthy dietary patterns, the results of the meta-analysis showed:
- significantly higher sperm concentrations (mean difference [MD] = 6.88 × 106 ml−1, 95% confidence interval [CI]: 1.26 × 106 ml−1–12.49 × 106 ml−1; P < 0.05)
- significant increase in total sperm count (MD = 16.70 × 106, 95% CI: 2.37 × 106–31.03 × 106; P < 0.05)
- significant increase in progressive sperm motility (MD = 5.85%, 95% CI: 2.59%–9.12%; P < 0.01) but there was no significant correlation between healthy dietary patterns and total sperm motility (MD: 6.86%, 95% CI: −0.25%–13.96%; P > 0.05).
- there was no significant association between a healthy dietary pattern and normal sperm morphology (MD: 0.28%, 95% CI: −0.33%–0.90%; P > 0.05)
- there was no significant association between a healthy dietary pattern and semen volume (MD: 0.04 ml, 95% CI: −0.20 ml–0.28 ml; P > 0.05).
Limitations:
- Included studies were all cross-sectional studies, and it is impossible to determine the causal relationship between the high intake of healthy dietary patterns and semen quality.
- The number of studies included was small, and there was not enough literature to support authors in drawing reliable conclusions.
- No comparison was made between specific diets such as dash vs Mediterranean.
Clinical practice applications:
- The authors concluded that dietary interventions should be considered in clinical work as part of the therapies improving male semen quality.
- Dietary interventions for men should be included as part of preconceptional clinical management,
- Dietary interventions for men should also be considered in infertility clinical management.
Considerations for future research:
- Randomised Clinical Trials should be conducted to build on these findings.
Abstract
The incidence of infertility has recently risen. Semen quality is an important male fertility indicator, and dietary factors can affect semen quality. We conducted this systematic review and meta-analysis to determine the effects of healthy dietary patterns on semen quality. A literature search was conducted in 3 databases (Embase, Web of Science and PubMed) on August 21, 2021. The included cross-sectional studies examined the influence of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and prudent diet patterns on semen quality parameters; six studies (1244 subjects) were included. By comparing high consumption with low consumption of healthy dietary patterns, the results of the meta-analysis showed significantly higher sperm concentrations (mean difference [MD] = 6.88 × 106 ml-1, 95% confidence interval [CI]: 1.26 × 106 ml-1-12.49 × 106 ml-1; P < 0.05), a significant increase in total sperm count (MD = 16.70 × 106, 95% CI: 2.37 × 106-31.03 × 106; P < 0.05), and a significant increase in progressive sperm motility (MD = 5.85%, 95% CI: 2.59%-9.12%; P < 0.01). The sperm concentration, progressive sperm motility, and total sperm count were significantly higher in men with higher versus lower consumption of healthy dietary patterns. However, the results must be interpreted with caution.
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Probiotic treatment with specific lactobacilli does not improve an unfavorable vaginal microbiota prior to fertility treatment-A randomized, double-blinded, placebo-controlled trial.
Jepsen, IE, Saxtorph, MH, Englund, ALM, Petersen, KB, Wissing, MLM, Hviid, TVF, Macklon, N
Frontiers in endocrinology. 2022;13:1057022
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Efforts to improve pregnancy rates remain largely focused on enhancing the quality of the transferred embryo. However, there is increasing awareness of the potential role of the intra-uterine environment as a determinant for success. The aim of this study was to determine if lactobacilli-loaded vaginal capsules are superior to placebo in improving a vaginal microbiota reported as unfavourable to implantation in women scheduled for fertility treatment. This study is a single-centre, two-arm, double-blinded, randomised controlled study. The study enrolled women aged 18–40 years who were referred to the Fertility Clinic and whose vaginal microbiota prior to fertility treatment had been diagnosed as an unfavourable. Participants (n=77) were randomised in a 1:1 ratio to either lactobacilli-loaded vaginal capsules or placebo. Results did not show any significant effect of treatment with lactobacilli-loaded vaginal capsules on the unfavourable vaginal microbiota profile among women referred to fertility treatment. However, the study showed the highly dynamic nature of the vaginal microbiota, with a spontaneous improvement rate of 34.2% (of the patients) one to three months after the baseline sample. Authors conclude that probiotics use for the improvement of vaginal microbiota should be tempered with some caution. More studies of both the vaginal and endometrial microbiota are required to confirm the efficacy of specific vaginal probiotics before they can be considered as a therapeutic solution.
Abstract
OBJECTIVE To investigate whether treatment with proprietary lactobacilli-loaded vaginal capsules improves an unfavorable vaginal microbiome diagnosed using a commercially available test and algorithm. DESIGN A randomized, double-blinded, placebo-controlled study was conducted in 74 women prior to undergoing fertility treatment at a single university fertility clinic between April 2019 and February 2021. The women were randomly assigned in a 1:1 ratio to receive one vaginal capsule per day for 10 days containing either a culture of more than 108 CFU of Lactobacillus gasseri and more than 108 CFU Lactobacillus rhamnosus (lactobacilli group) or no active ingredient (placebo group). Vaginal swabs for microbiota analysis were taken at enrollment, after treatment and in the cycle following treatment. PARTICIPANTS AND METHODS Women aged 18-40 years who prior to fertility treatment were diagnosed with an unfavorable vaginal microbiota, characterized by either a low relative load of Lactobacillus or a high proportion of disrupting bacteria using the criteria of the IS-pro™ diagnostic system (ARTPred, Amsterdam, the Netherlands), were enrolled in the study. The primary outcome measure was the proportion of women with improvement of the vaginal microbiota after intervention. RESULTS The vaginal microbiota improved after intervention in 34.2% of all participants (lactobacilli group 28.9%, placebo group 40.0%), with no significant difference in the improvement rate between the lactobacilli and placebo groups, RR = 0.72 (95% CI 0.38-1.38). CONCLUSION This study indicates that administering vaginal probiotics may not be an effective means of modulating the vaginal microbiome for clinical purposes in an infertile population. However, a spontaneous improvement rate of 34.2% over a period of one to three months, confirming the dynamic nature of the vaginal microbiota, indicates that a strategy of postponing further IVF treatment to await microbiota improvement may be relevant in some patients, but further research is needed. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, identifier NCT03843112.
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Menstruation-Related Disorders-Dysmenorrhea and Heavy Bleeding-as Significant Epiphenomena in Women With Rheumatic Diseases.
Orlandi, M, Vannuccini, S, El Aoufy, K, Melis, MR, Lepri, G, Sambataro, G, Bellando-Randone, S, Guiducci, S, Cerinic, MM, Petraglia, F
Frontiers in pharmacology. 2022;13:807880
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Rheumatic diseases (RDs) affect significantly more women than men, and for this reason, gynaecological disorders may have an additional negative impact on women’s health. The aim of this study was to describe gynaecological symptoms among fertile age women with RDs and their impact on quality of life. This study is a monocentric, cross-sectional observational study. Results show that a large number of women with RDs report menstrual disorders. In fact, more than half of the population reported of having dysmenorrhea since adolescence. Similarly, during fertile age, menstrual pain was frequently reported, and in 72% of the cases, the intensity resulted to be moderate/severe. Additionally, heavy menstrual bleeding was found in 38% of the patients during adulthood and in 52% of patients during adolescence. Authors conclude that the management of female patients with RDs is a challenge for clinicians and should include an accurate evaluation of gynaecological aspects (menstruation, fertility, maternity, and sexuality) as well as manage an interdisciplinary teamwork approach (rheumatologist and gynaecologists).
Abstract
Background: In women with rheumatic diseases (RDs) menstruation-related disorders have never been investigated. The aim of this study was to evaluate gynecological symptoms/disorders in fertile age women with RDs. Materials and methods: All patients (n = 200) filled up a self-administered questionnaire on their gynecological history, menstrual cycle pattern, menstrual-related symptoms, and quality of life (QoL). The RD group was then compared to a control group of 305 age-matched fertile age women. Results: Among patients with RDs, 58% had arthritis, 40% connective tissue diseases (CTDs), and 1.5% systemic vasculitis. No differences were observed between CTDs and arthritis, except for a family history of HMB which was more common among women with CTDs (p < .01). When compared to controls, women with RDs reported more frequent heavy menstrual bleeding (HMB) during adolescence (51.7 and 25.4%, respectively; p = .0001) and adult life (37.7 and 25.9%, respectively; p = .0065). Also, dysmenorrhea in adolescence was significantly more common among cases (55.6 and 45.4%, respectively; p = .0338). Gynecological pain (dysmenorrhea, non-menstrual pelvic pain, dyspareunia, dysuria, and dyschezia) in patients with RDs was more frequent than in controls (p = .0001, .0001, .0001, .0001, .0002, respectively). Considering women who reported moderate and severe symptoms in RDs, dysmenorrhea and dyspareunia remain significantly more frequent in women with RDs than in controls (p = .0001; p = .0022; respectively). QoL scores were significantly reduced in women with RDs, either in physical (p = .0001) and mental domains (p = .0014) of short-form 12. Conclusion: Women affected by RDs frequently presented menstruation-related disorders; thus, female patients with RDs should be questioned about gynecological symptoms and referred to the gynecologist for an accurate evaluation.
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Contribution of Lactobacillus iners to Vaginal Health and Diseases: A Systematic Review.
Zheng, N, Guo, R, Wang, J, Zhou, W, Ling, Z
Frontiers in cellular and infection microbiology. 2021;11:792787
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The vaginal microbiome is an important contributor to vaginal health. Here the dominance of Lactobacilli species, alongside their antimicrobial compounds play a critical role in contributing and protecting the vaginal milieu. Conversely the disruption or absence of Lactobacilli dominance is frequently associated with vaginal disease and infections. One of the Lactobacilli species prevalent in the vaginal microbiome is Lactobacillus iners. It was long overlooked in research due to it being so difficult to culture, and it was first identified in 1999 thanks to DNA sequencing. Researchers since discovered that the relationship between L. iners and vaginal health is far more complicated and ambiguous compared to the other Lactobacilli species. This systematic review explores the current knowledge of the characteristics of L. iners and its role in vaginal health and disease. The article discusses L. iners identification, genetic make up and differences to other Lactobacilli species and how they relate to vaginal health. The article also summarizes L. iners nutrient requirements and its role in diseases like dysbiosis, bacterial vaginosis, sexually transmitted infections and biofilm formation. Furthermore the authors look at the relation between L. iners and premature birthing, fertility and menstrual cycles. A final section in discusses the antimicrobial and immune sytem activating qualities of L. iners. In light of all these findings the authors describe L . iners as a very unique Lactobacilli due to its unusual characteristics. Whether L. iners is beneficial or pathogenic for the host remains controversial, as it can adapt to high and low pH environment and is seen in health and equally dysbiotic states of infection. Hence some describe it as a transitional species that colonizes the vagina after disturbances. It may be a risk factor for infections by contributing to the onset and maintenance of dysbiotic disturbances. Further studies are needed to clarify the role of L. iners and its role on vaginal health and whether it could serve as a biomarker for vaginal inflammation. This article is a useful summary about the characteristics and role of L. iners in vaginal health in disease.
Abstract
Lactobacillus iners, first described in 1999, is a prevalent bacterial species of the vaginal microbiome. As L. iners does not easily grow on de Man-Rogosa-Sharpe agar, but can grow anaerobically on blood agar, it has been initially overlooked by traditional culture methods. It was not until the wide application of molecular biology techniques that the function of L. iners in the vaginal microbiome was carefully explored. L. iners has the smallest genome among known Lactobacilli and it has many probiotic characteristics, but is partly different from other major vaginal Lactobacillus species, such as L. crispatus, in contributing to the maintenance of a healthy vaginal microbiome. It is not only commonly present in the healthy vagina but quite often recovered in high numbers in bacterial vaginosis (BV). Increasing evidence suggests that L. iners is a transitional species that colonizes after the vaginal environment is disturbed and offers overall less protection against vaginal dysbiosis and, subsequently, leads to BV, sexually transmitted infections, and adverse pregnancy outcomes. Accordingly, under certain conditions, L. iners is a genuine vaginal symbiont, but it also seems to be an opportunistic pathogen. Further studies are necessary to identify the exact role of this intriguing species in vaginal health and diseases.
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Implications of the vaginal microbiome and potential restorative strategies on maternal health: a narrative review.
Moumne, O, Hampe, ME, Montoya-Williams, D, Carson, TL, Neu, J, Francois, M, Rhoton-Vlasak, A, Lemas, DJ
Journal of perinatal medicine. 2021;49(4):402-411
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The vaginal microbiome is a complex community of bacteria that maintains and contributes to vaginal health and works together to protect the host from disease. Lactobacilli are the predominant species in a healthy vaginal microbiome. This review sought to summarize current evidence on how changes in the vaginal microbiome composition before and throughout pregnancy influence and contribute to several health conditions. The authors investigated the role of the vaginal microbiome in fertility and in-vitro fertilization (IVF), where evidence is still conflicting, followed by conditions that can present during pregnancy such as preterm labour, gestational diabetes, and preeclampsia. In preterm labour, lower levels of Lactobacillus and its D-lactic acid secretions have been observed as a common denominator; in gestational diabetes, it remains unclear whether the changes in the vaginal microbiome associated with the condition are causative or rather a result of the condition. Little research has been done regarding preeclampsia, but initial studies indicate there may be a link between the condition and the vaginal microbiome. The authors also reviewed the evidence on methods of restoring vaginal health, including oral and vaginally applied probiotics as well as vaginal microbiome transplants (VMT) - the transfer of vaginal secretions from a healthy donor. The paper discusses the evidence on the use of oral and locally applied probiotics for the aforementioned conditions, and the promising potential of VMTs alongside the risks and regulatory challenges that come with it. This review provides a helpful summary of the current understanding of the role of the vaginal microbiome in fertility and throught pregnancy.
Abstract
The vaginal microbiome undergoes dramatic shifts before and throughout pregnancy. Although the genetic and environmental factors that regulate the vaginal microbiome have yet to be fully elucidated, high-throughput sequencing has provided an unprecedented opportunity to interrogate the vaginal microbiome as a potential source of next-generation therapeutics. Accumulating data demonstrates that vaginal health during pregnancy includes commensal bacteria such as Lactobacillus that serve to reduce pH and prevent pathogenic invasion. Vaginal microbes have been studied as contributors to several conditions occurring before and during pregnancy, and an emerging topic in women's health is finding ways to alter and restore the vaginal microbiome. Among these restorations, perhaps the most significant effect could be preterm labor (PTL) prevention. Since bacterial vaginosis (BV) is known to increase risk of PTL, and vaginal and oral probiotics are effective as supplemental treatments for BV prevention, a potential therapeutic benefit exists for pregnant women at risk of PTL. A new method of restoration, vaginal microbiome transplants (VMTs) involves transfer of one women's cervicovaginal secretions to another. New studies investigating recurrent BV will determine if VMTs can safely establish a healthy Lactobacillus-dominant vaginal microbiome. In most cases, caution must be taken in attributing a disease state and vaginal dysbiosis with a causal relationship, since the underlying reason for dysbiosis is usually unknown. This review focuses on the impact of vaginal microflora on maternal outcomes before and during pregnancy, including PTL, gestational diabetes, preeclampsia, and infertility. It then reviews the clinical evidence focused on vaginal restoration strategies, including VMTs.