Gut microbiome linked to male reproductive disorders
Researchers believe the bacteria located in the gastrointestinal tract may be inherited from father to offspring determining later disease risk, such as obesity. In older males, this bacterium may promote conditions like prostatitis that can result in prostate cancer.
It has been well documented that the future health of offspring is influenced by the condition of the male parent. Paternal obesity in mice has been linked to various health effects, such as obesity, cardiovascular and reproductive disorders in first generation offspring.
Similar effects have been noted in humans but the mechanism of transmission to the offspring has yet to be defined.
Cheryl Rosenfeld, an associate professor of biomedical sciences in the Missouri College of Veterinary Medicine, and her team began by collecting the seminal fluid and vesicles from male mice. They then sequenced the DNA of the bacteria located in the reproductive organs and fluid.
Advanced bioinformatics tools and programs helped narrow down and identify each microorganism.
"The data showed that the bacterial composition found in the male reproductive tract contained potentially detrimental bacteria that can be transmitted to female reproductive partners and offspring," Rosenfeld said.
"Additionally, further testing showed this bacterial community contains the bacteria that may cause obesity in rats.”
Microbiomes are easily influenced by environmental factors such as temperature, the pH or acidity of the environment and whether there's a food source like probiotics or prebiotics or synbiotics to promote bacterial growth.
Seminal fluid significance
The male reproductive tract provides a unique environment in which bacteria thrive. Seminal fluid, which contains this bacterium, is located in temperature controlled, carbohydrate-rich conditions needed to feed bacteria.
This fluid is slightly basic (pH < 7.2) and contains fructose, proteins, enzymes, mucus, vitamin C, flavins, phosphorylcholine and prostaglandins.
Fructose is thought to provide the primary source of metabolic energy for the spermatozoa, but this nutrient can also be utilised by microorganisms, such as fructophilic lactic acid bacteria.
Therefore, the seminal vesicles could provide a unique niche for such microorganisms to thrive.
The researchers said understanding how these genetic and environmental factors influenced this particular microbiome could help in understanding how possible developmental disorders and diseases were passed down by fathers to their offspring.
In a similar study, it was speculated that fathers transmitted information via microbiota to their partners and progeny. The most likely source of such microbiota was the seminal vesicles.
In discussing the importance of these results, the researchers wrote that the microbiomes present within each of these environments may have evolved over time to the specific qualities of each niche.
Bacterial phyla that dominated in the seminal fluid, including Proteobacteria, Actinobacteria, Fusobacteria, and Firmicutes could utilise fructose and other carbohydrates produced by the seminal fluid glands as energy sources.
They agreed that gut dysbiosis could result in metabolic, neurological, and other disease states, pointing to two Lachnospiraceae that increased in number in the faecal samples of the male mice.
Gut colonisation by this bacterial family had been previously linked with increased body weight and hyperglycemia in mice.
Source: Nature/Scientific Reports
Published online ahead of print, doi:10.1038/srep23027
“Discovery of a Novel Seminal Fluid Microbiome and Influence of Estrogen Receptor Alpha Genetic Status.”
Authors: Angela B. Javurek, William G. Spollen, Amber M. Mann Ali, Sarah A. Johnson, Dennis B. Lubahn, Nathan J. Bivens, Karen H. Bromert, Mark R. Ellersieck, Scott A. Givan & Cheryl S. Rosenfeld