Causal Link between Gut Microbiota and Infertility: A Two-sample Bidirectional Mendelian Randomization Study

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This Mendelian randomization study found bidirectional causal links between gut microbiota composition and infertility, identifying specific genera and families associated with various reproductive diseases.

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This paper used a two-sample bidirectional Mendelian randomization framework to test potential causal relationships between gut microbiota composition and reproductive system diseases, including female and male infertility and endometriosis, using genetic instruments to infer directionality. It identified sixteen strong and sixty-one total causal associations, including Eubacterium hallii as protective against premature ovarian failure and as a pathogenic factor for endometriosis, and Erysipelatoclostridium as a pathogenic factor for multiple reproductive diseases such as PCOS and endometriosis. Reverse analyses suggested that endometriosis, orchitis, and epididymitis were associated with decreased bifidobacteria abundance, and that female infertility-related diseases had a greater impact on gut microbes than male infertility-related diseases. This paper is centrally about endometriosis — it reports gut-microbe causal effects on endometriosis and bidirectional effects between endometriosis and gut microbiota.

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Abstract

OBJECTIVE: To investigate the associations of the gut microbiota with reproductive system diseases, including female infertility, male infertility, polycystic ovary syndrome (PCOS), primary ovarian failure, endometriosis, uterine fibroids, uterine polyps, sexual dysfunction, orchitis, and epididymitis. METHODS: A two-sample bidirectional Mendelian randomization (MR) analysis was performed to evaluate the potential causal relationship between the composition of gut microbiota and infertility, along with associated diseases. RESULTS: Sixteen strong causal associations between gut microbes and reproductive system diseases were identified. Sixty-one causal associations between gut microbes and reproductive system diseases were determined. The genus Eubacterium hallii was a protective factor against premature ovarian failure and a pathogenic factor of endometriosis. The genus Erysipelatoclostridium was the pathogenic factor of many diseases, such as PCOS, endometriosis, epididymitis, and orchitis. The genus Intestinibacter is a pathogenic factor of male infertility and sexual dysfunction. The family Clostridiaceae 1 was a protective factor against uterine polyps and a pathogenic factor of orchitis and epididymitis. The results of reverse causal association analysis revealed that endometriosis, orchitis, and epididymitis all led to a decrease in the abundance of bifidobacteria and that female infertility-related diseases had a greater impact on gut microbes than male infertility-related diseases did. CONCLUSIONS: The findings from the MR analysis indicate that there is a bidirectional causal relationship between the gut microbiota and infertility as well as associated ailments. Compared with ovarian diseases, uterine diseases are more likely to lead to changes in women's gut microbiota. The findings of this research offer valuable perspectives on the mechanism and clinical investigation of reproductive system diseases caused by microorganisms.
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Abstract

Objective To investigate the associations of the gut microbiota with reproductive system diseases, including female infertility, male infertility, polycystic ovary syndrome (PCOS), primary ovarian failure, endometriosis, uterine fibroids, uterine polyps, sexual dysfunction, orchitis, and epididymitis.

Methods

A two-sample bidirectional Mendelian randomization (MR) analysis was performed to evaluate the potential causal relationship between the composition of gut microbiota and infertility, along with associated diseases.

Results

Sixteen strong causal associations between gut microbes and reproductive system diseases were identified. Sixty-one causal associations between gut microbes and reproductive system diseases were determined. The genus Eubacterium hallii was a protective factor against premature ovarian failure and a pathogenic factor of endometriosis. The genus Erysipelatoclostridium was the pathogenic factor of many diseases, such as PCOS, endometriosis, epididymitis, and orchitis. The genus Intestinibacter is a pathogenic factor of male infertility and sexual dysfunction. The family Clostridiaceae 1 was a protective factor against uterine polyps and a pathogenic factor of orchitis and epididymitis. The results of reverse causal association analysis revealed that endometriosis, orchitis, and epididymitis all led to a decrease in the abundance of bifidobacteria and that female infertility-related diseases had a greater impact on gut microbes than male infertility-related diseases did.

Conclusions

The findings from the MR analysis indicate that there is a bidirectional causal relationship between the gut microbiota and infertility as well as associated ailments. Compared with ovarian diseases, uterine diseases are more likely to lead to changes in women’s gut microbiota. The findings of this research offer valuable perspectives on the mechanism and clinical investigation of reproductive system diseases caused by microorganisms. Similar content being viewed by others

References

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Additional information This work was supported by grants from the Guangdong Basic and Applied Basic Research Foundation (No. 2021A1515220178) and 2024 Independent Innovation Fund of Huazhong University of Science and Technology (No. 5003519022). Supplementary data Rights and permissions About this article Cite this article Zhang, Jx., Li, Ql., Wang, Xy. et al. Causal Link between Gut Microbiota and Infertility: A Two-sample Bidirectional Mendelian Randomization Study. CURR MED SCI 44, 1312–1324 (2024). https://doi.org/10.1007/s11596-024-2931-x Received: Accepted: Published: Version of record: Issue date: DOI: https://doi.org/10.1007/s11596-024-2931-x

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Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome Gastrointestinal Microbiome

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