The results are surprising because the sperm of the eight diabetic patients studied looked normal under the microscope, though there was a mild decrease in quantity. But closer analysis revealed damage on a much smaller level, the study found.
Specifically, the researchers found damage in the sperm's RNA transcripts. The conversion of DNA to RNA is the first step in the process of gene expression, that is, the production of a cellular end-product (such as a protein) from an original DNA precursor. Even more interesting was the type of genes involved. The researchers found that genes important in DNA repair were affected, thereby diminishing the cell's ability to repair sperm DNA after damage has occurred.Sperm DNA damage has been shown to lead to decreased embryo viability as well as some childhood illnesses, including some cancers.
Why is this damage occurring at all? Dr. Con Mallidis, who headed the research, suggests that it may be due to the build-up of advanced glycation end products (AGEs) in the reproductive tracts of the diabetic men. Derived from sugars, AGEs are typically found in higher levels in diabetic patients. They are correlated with other diabetic health issues caused by oxidative DNA damage, so the build-up of AGEs in the reproductive tract may just be the culprit.
The next step for the researchers will be to determine the exact mechanism by which AGEs actually lead to damage to the DNA molecule. In the meantime, Mallidis notes, it is probably wise to try to reduce the formation and accumulation of AGEs in diabetic patients as much as possible, either by diet or by dietary supplement.
The ability for DNA to repair itself is critically important under any circumstances, but sperm DNA damage has been shown to lead to decreased embryo viability as well as some childhood illnesses, including some cancers. The study was conducted at Queen's University in Belfast, Ireland, and reported at the European Society of Human Reproduction and Embryology on July 9, 2008.
