Effects of Vitamin D on Human Sperm DNA Fragmentation

Vitamin D plays an important role in bone metabolism and has also been discovered to influence male reproduction. Vitamin D binds to the Vitamin D receptor which then can bind to Vitamin D response elements in the DNA which can alter transcription. By changing transcription it can have long term effects on cellular metabolism. Previous studies have demonstrated abnormalities in sperm motility and morphology in males who are Vitamin D deficient. The mechanism by which Vitamin D affects spermatogenesis (formation of sperm) is unknown. One possibly mechanism by which deficient Vitamin D may affect sperm formation is through DNA fragmentation. The head of the sperm contains all the DNA. When a sperm cell is made the DNA in the nucleus must be super compacted to accomplish sperm formation. To sufficiently compact the DNA, first the DNA is 'turned off' and then very tightly wound (or compacted) into toroids (like small tires) which are stacked one on top of another. During this process of compaction the DNA will occasionally break or fragment. The egg can repair the DNA fragmentation as long as there is not a large amount of breakage. If the DNA fragmentation exceeds a certain amount then fertilization and early development of the embryo may be adversely affected. DNA fragmentation can be tested by using the Sperm Chromatin Structure Assay (SCSA), which the investigators currently measure in males who present with their partners with infertility. Previous studies have suggested that the abnormalities in sperm due to vitamin D deficiency may be related to increased DNA fragmentation. This study will assist in understanding the cause of sperm abnormalities in subjects with Vitamin D deficiency.

This is a prospective, cohort study. In this study male patients who present with inability to conceive will be asked to be involved in this study. After agreement with the study, a blood sample drawn which will be tested for Vitamin D level. The investigators will then compare sperm DNA fragmentation between normal Vitamin D levels, Vitamin D insufficiency, and Vitamin D deficiency. All infertile males presenting to the investigators' infertility clinic have a Semen analysis and Sperm chromatin Structure Assay (SCSA). The research part of the study will be to obtain the Vitamin D level.