A recent article in the Journal Nature reports on the “microbiome” in the testicle. A microbiome refers to populations of different strains of bacteria, viruses and yeast or fungi that occupy every surface of the human body. Some have estimated that the average person’s body s host to about 30 trillion microorganisms. These microbes are being shown to play a significant role in both health and disease, including a role in inflammation.
Investigators Alfano et al in Human Reproduction, Volume 33, Issue 7, 1 July 2018, Pages 1212–1217, Report on the presence of “dysbiosis” or an aberrant microbiome in the testes of men with germ cell aplasia (no sperm making cells present within the testis) vs the testes of men with normal sperm production.
The presence of bacteria was determined by testing testicular tissue of men who had no sperm in the ejaculate. Even when no sperm are present in the semen, it is possible that the testes are producing sperm. In some cases, sperm production is normal, but there is a blockage to the sperm coming out; the most common example of that would be in a man who had a vasectomy. In some cases sperm production is present but at levels so low that there is not enough sperm to come out into the ejaculate. This is called “hypospermatogenesis”. But sometimes there just aren’t any sperm making cells in the testis but rather the seminiferous tubules are populated only by support cells called sertoli cells. This is called Sertoli Cell only or Germ Cell aplasia.
A technique called Polymerase chain reaction or PCR was used to amplify specifically bacterial DNA from testis tissue specimens. This is a technique that allow identification of even cellular amounts of specific DNA. Special software was able to use the quantified results of PCR to determine relative concentrations of DNA from different bacteria.
Results showed not only that bacteria were present in both normal and absent sperm production but that bacterial profiles were different. According to the article, the bacteria Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria were associated with a normal sperm production where as only Actinobacteria and Firmicutes were retrieved in men without sperm. Furthermore, a significant reduction of Clostridia and absence of Peptonyphilus asaccharolyticus was observed in negative sperm retrievals. In other words, a decreased variety of bacteria was seen in men without sperm.
The authors point out that the same main four “phyla” of bacteria seen in men with sperm production are also seen in the normal human gut; however, the gut of the elderly often has less “biodiversity” a finding which may suggest that testes of men without sperm may be showing signs of premature aging.
The findings of these authors may have opened a new Window into the understanding of the pathophysiology of Male infertility. Where this approach will lead to the field is unknown, but it is hoped that it will eventually result in possible new options for therapy.