The microbiome is a specialized collection of bacteria residing in the human body. Mostly famous for their existence in the human gut, these communities of microorganisms have been known to influence processes like digestion and immune responses. In a new report, scientists discovered the male reproductive also harbors a unique microbiome. But far from being beneficial, the researchers suspect this microbiome may be involved in causing male reproductive problems.
Bacteria are present throughout our bodies, and some confer health benefits and some can cause disease. Scientists have known that bacteria are present in semen samples of men and can be transmitted during sexual intercourse, but they didn’t know the source of this bacteria. They suspected the seminal vesicles to be the source, as the seminal fluids from these glands are temperature controlled and rich in carbohydrates – ideal living conditions for bacteria to thrive.
"Microbiomes are influenced by many factors such as temperature, the pH or acidity of the environment and whether there's a food source to promote bacterial growth," said Cheryl Rosenfeld, investigator in the Bond Life Sciences Center and senior study author.
To address this question, scientists from the University of Missouri-Columbia collected seminal fluid and vesicles from male mice, including normal and those that were missing the estrogen receptor-alpha (ESR1) gene. They then sequenced the DNA from those fluids, looking for matches to known microorganisms.
Their findings confirmed the presence of a microbiome unique to the male seminal vesicles in the mice. Furthermore, the bacteria living there included Propionibacterium acnes, which has the potential to be causative agent of chronic prostatitis, a possible precursor to prostate cancer in males. The composition of the bacteria was influenced by the ESR1 gene, the absence of which reduced P. acnes levels, indicating estrogen’s involvement.
Other types of bacteria living in the seminal vesicles of the mice included Lachnospiraceae and Christensenellaceae, which were previously implicated in obesity.
“Understanding how these genetic and environmental factors influence this particular microbiome could help in understanding how possible developmental disorders and diseases are passed down by fathers to their offspring," said Rosenfeld.
Aside from direct DNA sequence information in the sperm, researchers have speculated several alternative ways in which information could be transmitted from fathers to their offspring. One of the proposed mechanisms is information transmission via the microbiota from the male to their partners and subsequent progeny. However, to validate this connection, the researchers must next demonstrate the proposed reproductive detriments in the mouse progeny.
Additional source: EurekAlert!