Free Radical Theory of Aging: Implications in Male Infertility

Date: 7-17-2009

Urology. 2009 Jul 16. [Epub ahead of print] Desai N, Sabanegh E Jr, Kim T, Agarwal A.   Center for Reproductive Medicine, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio; Department of Internal Medicine, Staten Island University Hospital, Staten Island, New York.

A review article in the journal Urology  from the Cleveland Clinic points out that reactive oxygen species (ROS) can damage mitochondria (sperm engine for motility) DNA and membranes as well as the sperm nuclear DNA that is crucial for genetic integrity and well being for the embryo.  Due to the continuous production of reactive oxygen species that breaks sperm DNA (ROS) it was suggested that this plays a central role in the age-related decrease in male fertility.

DPE: This suggestion is strongly supported by our previous study on the effects of age on sperm DNA fragmentation.  (see CAUSES/AGE on WEB site)  On average men in their early 20’s have an approximate 3-5% DFI that then increases about 5% per year.  The average age of a man to reach our clinically significant threshold for placing a man at risk for infertility is age 50.  Men have great variability so that a 30 yr old man could have a 60% DFI while a 60 yr old man may have a 15% DFI. 

Action point:  Infertility couples should have an SCSA test to determine if the primary cause of infertility is a high %DFI in sperm.  If so, there may be means to bring this to a lower number that is more compatible with fertility.