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Moving forward, Oud and her researchers are working to screen the DNA of more patients and their parents in search of patterns in the locations of these novel mutations and to further examine the role these 22 DNMs play. "We are interested in learning more about the function of the genes that are affected by a mutation since their link with infertility has never been established before," Oud says. "We are studying the role of these genes in residual material from testicular biopsies of our patients. Additionally, we are performing experiments in fruit flies to study whether disruption of the newly associated genes causes infertility in flies." DNA DAMAGE AND RECURRENT MISCARRIAGE Another study, published in the journal Clinical Chemistry in January 2019, found that men whose partners experienced three or more successive miscarriages were more likely to have higher levels of both DNA damage and reactive oxygen species in their sperm cells. Channa Jayasena, MD, PhD, the study's lead researcher and a Clinica l Senior Lecturer and Consultant in Reproductive Endocrinology and Andrology at Imperial College and Hammersmith Hospital in London, England, suspects these findings are interrelated. " R e a c t ive ox y gen s p e cie s pl ay a critical role in cellular metabolism and are necessary for the normal function- ing of mitochondria," Dr. Jayasena says. "However, reactive oxygen species can also cause cellular damage and cell death if they are produced in excessive amounts." Dr. Jayasena says he and his research team are now looking into what is trigger- ing these high levels of reactive oxygen species. He hopes the results of this research will help lead to new potential treatments, such as antioxidant supple- ments, for men struggling with infertility and/or recurrent miscarriage. "There is a widening awareness around the role of the male partner when it comes to reproductive disorders," Dr. Jayasena says. " There have been tremendous advancements in the treatment of women for reproductive disorders over the past few decades, and I think we are just now playing catch-up for the men." n Chlamydia and Male Infertility W HILE CHL A M Y DIA H A S long been highlighted as a potential cause for infertility in women, much less atten- tion has been placed on the potential effect this sexually transmitted infection has on male fertility. However, a recent study published in the journal Human Reproduction found that chlamydia was present in 40% to 54% of the fixed diagnostic testicular biopsies collected from a group of 95 moderately to severely infertile men with no known cause of infertility. Chlamydia was also present in three (16.7%) of the fresh therapeutic testicular biopsies collected from a separate group of 18 mod- erately to severely infertile men — 13 of whom, including the three that tested positive for chlamydia, had no known cause of infertility. Two of these three men tested nega- tive for chlamydia based on a urine test (a urine test result was not able to be provided for the third participant). Additionally, chlamydia- specific antibodies were present in 12 (66.7%) of these 18 fresh biopsies — an indication that the men were previously exposed to chlamydia trachomatis, the bacteria responsible for chlamydia infections. While these findings do not demonstrate causality, this the first study to come forward with evidence that previously undetected cases of chlamydia can reside in testicular tissue and to suggest that these hidden infections may be a large contributor to male infertility. " Male infertility is still an understudied field and requires more awareness, attention and funding." — MANON OUD, MSC, PHD CANDIDATE AT THE RADBOUD UNIVERSITY MEDICAL CENTRE IN NIJMEGEN, THE NETHERLANDS M D N E W S . C O M /// M D N E W S C E N T R A l P E N N S y lvA N I A ■ 2 0 2 0 1 5