A new study says that diabetes adversely affects male fertility.
The study led by Dr. Con Mallidis from Queen's University, Belfast, UK, has found that that diabetes can cause DNA damage in sperm.
For the study, the researchers studied semen samples from men with diabetes who were receiving insulin therapy. On initial routine microscopic examination the semen samples appeared normal, apart from a slight decrease in volume.
"But when we looked for DNA damage, we saw a very different picture," said Dr. Mallidis.
"Sperm RNA was significantly altered, and many of the changes we observed are in RNA transcripts involved in DNA repair. And comparison with a database of men of proven fertility confirmed our findings."
"Diabetics have a significant decrease in their ability to repair sperm DNA, and once this is damaged it cannot be restored," he said
"We were particularly interested to see a fourteen-fold decrease in the expression of a protein called ornithine decarboxylase, which is responsible for the production of spermine and spermidine, compounds responsible for cell growth that help stabilise the structure of DNA.
"We also found that spermatogenesis 20, a factor unique to the testis and whose function remains unknown, was greatly increased. Taken together, these factors indicate clearly that having diabetes has a direct influence on the health of semen," he added.
Over the years possible causes for sperm DNA fragmentation have been suggested but to date the exact mechanism for the damage remains unknown.
"We found a class of compounds known as advanced glycation end products (AGEs) in the male reproductive tract. These are formed as the result of glycation (the addition of sugar)," said Dr. Mallidis, "and accumulate during normal ageing.
"They are dependent on life style - diet, smoking etc - and in many diabetic complications are centrally implicated in DNA damage. We believe that they play a similar role in the male reproductive system," he added.
The study was presented at 24th annual conference of the European Society of Human Reproduction and Embryology.