Researchers have found that diabetes may affect sperm quality, after a study comparing the DNA in sperm from diabetic and non-diabetic men found more DNA damage in the sperm cells of the diabetic men.
The study, conducted by the research group at Queen’s University Belfast, with findings published in the journal Human Reproduction, found that around 52 per cent of the DNA in the sperm cells of diabetic men was fragmented, compared with only 32 per cent for the non-diabetic men. Fragmentation of the DNA in sperm is one of the main causes of male infertility, because it prevents the sperm from delivering intact genetic information to the egg, which is required for the creation of a viable embryo.
The study compared the sperm from 27 diabetic men with that from 29 non-diabetic men in their early 30s. Dr Ishola Agbaje, who lead the research project, said, ‘Our study identifies important evidence of increased DNA fragmentation of nuclear DNA and mitochondrial DNA deletions in sperm from diabetic men’. He stated that these findings would have implications for male fertility, which has already been decreasing over the last 50 years. The increasing global incidence of diabetes could further propel the decline in male fertility.
Professor Sheena Lewis, director of the Reproductive Medicine Research Group, and co-author of the paper, said that the study was very small, and so served to highlight a possible concern. She stated that ‘our study shows increased levels of sperm DNA damage in diabetic men. From a clinical perspective this is important, particularly given the overwhelming evidence that sperm DNA damage impairs male fertility and reproductive health’.
Transcription is the synthesis of RNA under the direction of DNA, and is the first step towards gene expression, where the information from the gene becomes a product such as a protein translating the genetic information into a cellular function. If there are errors in transcription, there will also be errors in the function of the gene.
Sperm DNA quality is known to be associated with decreased embryo quality, low embryo implantation rates, higher miscarriage rates, and some serious childhood diseases, in particular some childhood cancers. Over the years possible causes for sperm DNA fragmentation have been suggested but to date the exact mechanism for the damage remains unknown, say the scientists.
Professor Lewis said that further research would be needed to quantify the exact nature of the DNA damage caused by diabetes, and whether there were additional health effects for the children of diabetic fathers. Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, stressed the importance of the quality of sperm DNA, and further said that ‘it would be important to understand the mechanism by which this damage occurs so that if it can be avoided we can work out how to do this’.
Matt Hunt, science information office at Diabetes UK, called for further research, after labelling the findings alarming. He said ‘this is the first research to suggest DNA damage may be occurring at a cellular level and that it is a cause for great concern’.