Microbiota, Prostatitis, and Fertility: Bacterial Diversity as a Possible Health Ally

A systematic and comprehensive review of the role of microbiota in urinary chronic pelvic pain syndrome

BACKGROUND

Many genitourinary tract disorders could be attributed partly to the microbiota. This study sought to conduct a systematic review of the role of the microbiota in urinary chronic pelvic pain syndrome (UCPPS).

METHODS

We searched Embase, Scopus, Web of Science, and PubMed with no time, language, or study type restrictions until December 1, 2023. The JBI Appraisal Tool was used to assess the quality of the studies. Study selection followed the PRISMA statement. Studies addressing microbiome variations among patients suffering from interstitial cystitis/bladder pain syndrome (IC/BPS) or chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and a control group were considered eligible.

RESULTS

A total of 21 studies (1 UCPPS, 12 IC/BPS, and 8 CP/CPPS) comprising 1125 patients were enrolled in our final data synthesis. It has been shown that the reduced diversity and discrepant composition of the gut microbiota may partly be attributed to the UCPPS pathogenesis. In terms of urine microbiota, some operational taxonomic units were shown to be elevated, while others became less abundant. Furthermore, various bacteria and fungi are linked to specific clinical features. Few investigations denied UCPPS as a dysbiotic condition.

CONCLUSIONS

Urinary and intestinal microbiota appear to be linked with UCPPS, comprising IC/BPS and CP/CPPS. However, given the substantial disparity of published studies, a battery of prospective trials is required to corroborate these findings.

Prostate and gut: Any relationship? A narrative review on the available evidence and putative mechanisms

BACKGROUND

Gut microbiome is a community of microorganisms that lives in the human intestine and exerts various functions on the host, including metabolic, immunoregulatory, and control over cell proliferation. Gut microbiome alterations have been associated with various pathological conditions, such as diabetes mellitus, obesity, and cardiovascular diseases. Gut-prostate axis is explained by the association between gut microbiome quantitative and functional alterations along with increased intestinal epithelial permeability with prostatediseases. However, the pathophysiological mechanisms and clinical importance of this association are not completely clarified yet.

METHODS

We conducted a narrative review of the most relevant articles in the Medline (US National Library of Medicine, Bethesda, MD, USA), Scopus (Elsevier, Amsterdam, The Netherlands) and Web of Science Core Collection (Thomson Reuters, Toronto, ON, Canada) databases. No chronological restrictions were applied, and the most related papers published until December 2023 were included.

RESULTS

Gut microbiota (GM) and its metabolites are capable of modifying host androgen level, as well as prostate cancer (PCa) therapy response. Moreover, patients with inflammatory bowel disease have higher rates of prostatitis-like symptoms and a potential risk of developing PCa.

CONCLUSIONS

There is evidence that interventions on the GM and its metabolites have a high potential to serve as diagnostic and therapeutic tools for prostate diseases, including PCa.

Immune regulatory cytokines in seminal plasma of healthy men: A scoping review and analysis of variance

OBJECTIVE

Seminal plasma cytokines are associated with fertility and reproductive health, but progressing their clinical utility is hampered by absence of reference data on concentration ranges of relevant cytokines in healthy men. We employed a systematic approach to assemble current evidence on the concentrations of immune regulatory cytokines present in seminal plasma (SP) of normozoospermic and/or fertile men and evaluated the impact of different platform methodologies for cytokine quantification.

EVIDENCE REVIEW

A systematic literature search was performed utilising PubMed, Web of Science and Scopus. Databases were searched from inception until 30th June 2022 inclusive, using combinations of keywords pertaining to seminal fluid and cytokines, and was restricted to human participants. Original data with values reported as concentration of specific cytokines in SP of men clearly defined as fertile or normozoospermic were extracted from studies written in English.

RESULTS

A total of 3769 publications were initially identified, of which 118 fulfilled the eligibility criteria for inclusion. A total of 51 individual cytokines are detectable in SP of healthy men. The number of studies reporting on each cytokine range from 1 to >20. The reported concentrations for many cytokines linked with fertility status, including IL6, CXCL8/IL8, and TNFA, are highly variable between published studies. This is associated with the different immunoassay methodologies utilised and may be exacerbated by a lack of validation of assays to ensure suitability for SP assessment. Due to the large variation between studies, accurate reference ranges for healthy men cannot be determined from the published data.

CONCLUSIONS

The concentrations of cytokines and chemokines detected in SP is inconsistent and highly variable between studies and cohorts, limiting current capacity to define reference ranges for cytokine concentrations in fertile men. The lack of standardisation in methods used to process and store SP, and variation in platforms used to evaluate cytokine abundance, are factors contributing to the observed heterogeneity. To progress the clinical utility of SP cytokine analysis will require standardisation and validation of methodologies so that reference ranges for healthy fertile men can be defined.

Possibilities and limitations of using low biomass samples for urologic disease and microbiome research

With the dogma of sterile urine no longer held as truth, numerous studies have implicated distinct changes in microbial diversity and composition to diseased subgroups in both benign and malignant urological diseases, ranging from overactive bladder to bladder and prostate cancer. Further facilitated by novel and effective techniques of urine culture and sequencing, analysis of the genitourinary microbiome holds high potential to identify biomarkers for disease and prognosis. However, the low biomass of samples included in microbiome studies of the urinary tract challenge researchers to draw definitive conclusions, confounded by technical and procedural considerations that must be addressed. Lack of samples and adequate true negative controls can lead to overestimation of microbial influence with clinical relevance. As such, results from currently available studies and assessment of their limitations required a thorough understanding. The purpose of this narrative review was to summarize notable microbiome studies in the field of urology with a focus on significant findings and limitations of study design. Methodological considerations in future research are also discussed.

Molecular analysis of microorganisms in the semen and their impact on semen parameters

OBJECTIVE

Chronic genitourinary infections can alter male fertility and even promote carcinogenic processes. This study aimed to evaluate the effect of the presence in the semen of microorganisms on semen quality.

MATERIALS AND METHODS

Clinical symptoms and conventional and functional seminal parameters of eleven fertile donors and ten volunteers with prostatitis-like symptoms were evaluated. Nitric oxide, antioxidant capacity, and pro-inflammatory cytokines in semen and seminal plasma samples were also quantified. Finally, the expression of the ROR-γT, FoxP3, and T-bet genes in semen and the presence of DNA of microorganisms associated with prostatitis in urine and semen were evaluated.

RESULTS

When compared with fertile donors, volunteers with chronic prostatitis-like symptoms reported erectile dysfunction (0% vs. 10%, p = 0.2825) and premature ejaculation (0% vs. 40%; p = 0.0190). No statistically significant differences were observed in seminal parameters, cytokine measurement, antioxidant capacity, nitric oxide concentration and ROR-γT, FoxP3, T-bet. Microorganisms responsible for sexually transmitted infections and some bacteria associated with the microbiota and infections in the prostate gland were detected. In the semen from the subjects with prostatitis-like symptoms T. vaginalis DNA was detected; in addition, N. gonorrhoeae DNA was also detected in semen and urine samples. S. pyogenes was detected in the urine samples from the control group.

CONCLUSIONS

Prostatitis-like symptoms are a common finding in young men that affect sexual and reproductive health, but not always the seminal parameters or fertility. The presence of prostatitis- like symptoms does not affect seminal quality. However, it appears to be associated with an increased likelihood of erectile dysfunction and premature ejaculation. Thus, affecting the quality of life and sexual and reproductive health.