Negative effect of increased body weight on sperm conventional and nonconventional flow cytometric sperm parameters.

Although with some discrepancy, obese men have been reported to have the worst conventional sperm parameters, but little is known about the effects of body weight on sperm mitochondrial function, chromatin condensation and apoptosis. This study was undertaken to evaluate conventional and nonconventional sperm parameters in nonsmoking overweight or obese men without any other cause known to alter sperm parameters. Fifty overweight, 50 obese, and 50 normal-weight healthy nonsmoking men were carefully selected. Each man underwent up to 2 sperm analyses and evaluation of mitochondrial membrane potential (MMP), phosphatidylserine (PS) externalization, chromatin compactness, and DNA fragmentation by flow cytometry. Overweight and obese men had significantly lower sperm progressive motility and normal forms than controls. They also had a significantly higher percentage of spermatozoa with low MMP. Obese, but not overweight, men showed a significantly higher percentage of spermatozoa with PS externalization, an early sign of apoptosis, and a lower percentage of viable spermatozoa. A significant increased percentage of spermatozoa with abnormal chromatin compactness was found in both overweight and obese men, whereas only obese men had a significantly higher number of spermatozoa with DNA fragmentation compared with controls. Healthy nonsmoking overweight and obese men have worse conventional and nonconventional sperm parameters than normal-weight controls. The important role played by these parameters in a couple's fertility suggests a program of body weight loss among the therapeutic repertoire for male infertility.