(260) Functional and Taxonomic Urine Microbiome Differences in Men with Abnormal Semen Analysis Parameters
Authors: Osadchiy V , Belarmino A , Kianian R , Sigalos J , Ancira J , Kanie T , Magnum S , Tipton C , Hsieh TM , Mills J , Eleswarapu S 
Published: February 2024

Abstract

Introduction
Male factors contribute to nearly half of all cases of infertility. Next-generation sequencing technologies have allowed for a more nuanced understanding of the widespread influence of the microbiome on health and human disease. Recent evidence has emerged revealing a potential role for the urinary microbiome in impacting male fertility and subfertility, though studies on this topic are sparse.

Objective
Here, we explore the complex relationship between the urine microbiome and alterations of SA parameters.

Methods
Men presenting for fertility evaluation or men presenting for vasectomy consultation with proven biological paternity were recruited. Clinical data and urine samples were collected from the patients and SA was performed. Patients were then stratified according to alterations in SA parameters. Urine samples underwent DNA extraction, PCR amplification and 16S rRNA sequencing. Taxonomic microbiome community profiling was performed. Predictive metagenomics was performed using Tax4Fun2 with reference to the KEGG database.

Results
N = 73 participants were included in the study and were stratified based on alterations, or lack thereof, in SA parameters. Men with abnormal sperm motility (N = 27) showed a higher abundance of urine Dialister micraerophilus (p = 0.0322) compared to those with normal sperm motility (N = 46). This relationship persisted on canonical correlational analysis (r = 0.439, p = 0.0114). Furthermore, when stratifying by sperm motility, nine differentially abundant pathways emerged from predictive metagenomic analysis including pathways critical for basic microbial cell functioning (intermediary metabolism pathways, FoxO signaling, longevity regulating pathways) in addition to pathways synthesizing and breaking down potentially bioactive metabolites (notably long- and short-chain fatty acid metabolism). Men with abnormal sperm concentration (N = 20) showed a lower abundance of urine Enterococcus faecalis (p = 0.0121) and urine Staphylococcus aureus (p = 0.0375), compared to those with normal sperm concentration (N = 53). These findings are outlined in the differential abundance box plots generated from the Analysis of composition of Microbiota with Bias Correction (ANCOM-BC) in Figure 1 and the differential abundance box plots from the predictive functional analysis in Figure 2.

Conclusions
Our exploratory analysis suggests a role for not just an altered microbial taxonomic profile but also an altered functional profile in men with abnormal SA parameters. These changes in SA parameters may come about through differences in urine microbial metabolite production including short-chain fatty acids or byproducts of intermediary metabolic processes such as those that may contribute to a pro-inflammatory microenvironment. These findings appear to be aligned with the very limited number of studies exploring similar lines of inquiry. These pathways and microbial communities may represent potential therapeutic targets. Further, more mechanistic, investigations are necessary.

Disclosure
Any of the authors act as a consultant, employee or shareholder of an industry for: MicrogenDx, Metuchen Pharmaceuticals, Antares Pharma, Boston Scientific, and Endo Pharmaceuticals.