Chlamydia in Testicular Tissue Linked to Male Infertility

Infectious diseases, such as mumps virus infection of the human testis, are known to play a role in spermatogenic dysfunction and have been associated with abnormal sperm parameters. Bacteria including Escherichia coli, mycoplasmas and Chlamydia trachomatis in human semen are also associated with abnormal sperm parameters.

The potential impact of undiagnosed sexually transmitted chlamydia infection on men's fertility has been highlighted in a study, which for the first time found chlamydia in the testicular tissue biopsies of infertile men whose infertility had no identified cause. Challenges in attributing male infertility to chlamydia infection include a wide diversity in diagnostic approaches.

Biomedical scientists at the Queensland University of Technology (Herston, Australia) collected 100 diagnostic (fixed) and 18 therapeutic (fresh) human testicular biopsies during sperm recovery procedures from moderately to severely infertile men in a cross-sectional approach to sampling. Two chlamydial markers were detected: the general marker major outer membrane protein (MOMP) and the active replication marker TC0500. Sections of 4 μm were dewaxed and rehydrated using a Leica ST5010-CV5030 Integrated Workstation.

The slides were processed and staining was validated using primary antibody only, secondary antibody only and DAB only controls. Stained slides were scanned using Leica Biosystems’ Aperio AT Turbo. QIAamp DNA FFPE Tissue Kit was used to extract DNA from fixed biopsies. C. trachomatis 16S rRNA DNA was detected using real-time polymerase chain reaction. Serum samples matched to fresh biopsies were assayed for C. trachomatis-specific antibodies.

The scientists reported that Chlamydia was found in 43/95 men (45.3 %) of fixed testicular biopsies, and all the men in this group had no defined cause of infertility. Chlamydia was also found in 3/18 men (16.7 %) of fresh testicular biopsies, obtained during patient sperm recovery procedures. These three men, and another 10 in the group, had no identified cause for their infertility. In 12 of the 18 men providing the fresh biopsies (66.7%) Chlamydia trachomatis-specific antibodies were found in serum, indicating the men had been exposed to the bacteria, but all were asymptomatic and said they had not been diagnosed with any sexually transmitted infection.

Kenneth W. Beagley, PhD, a Professor of Immunology and a senior author of the study said, “Chlamydia infection has been associated with women's infertility but much less is known about its impact on male infertility, particularly if men do not experience symptoms, which is estimated to be in about 50% of cases. When people have no symptoms they can unknowingly pass on the infection to sexual partners. This is the first reported evidence of Chlamydia infection in human testicular tissue, and while it can't be said that Chlamydia was the cause of the infertility of the men, it is a significant finding. It reveals a high rate of previously unrecognized Chlamydia infection and the potential role of infection in the failure of sperm to develop in the testes.” The study was published on October 4, 2019, in the journal Human Reproduction.

Related Links:
Queensland University of Technology