Vitamin D regulates how the body absorbs calcium and the cells which build up and break down bone tissue. In recent years, researchers have discovered new effects from vitamin D, and now sperm cells have also come under the microscope in studies of this important vitamin which we get from the sun and from eating fish. It appears that vitamin D has a particularly favourable effect on sperm cells, and after vitamin D supplementation a rapid increase in the concentration of calcium has been observed, which improves sperm motility and promotes the processes required to fertilize the egg.
The thesis was published in its entirety in the international scientific journal
Nature Reviews Endocrinology
and the research group, headed by Dr. Martin Blomberg Jensen from the Department of Growth and Reproduction, describe how the enzymes and the receptor which, respectively, activate and ensure protein response to vitamin D are also expressed in the testicle and sperm cells. The basic findings have huge clinical potential and they may lead to an important tool in fertility treatment and for future research into male reproduction.
Good marker of semen quality"
In fact, with just a colour test for one of the proteins that absorb vitamin D, it is possible to distinguish between cells from normal and infertile men, as men with poor semen quality do not express these proteins in their sperm cells. In addition to its use as a marker for good semen quality, it seems that the property can also be used functionally in connection with assisted reproduction, as with activated vitamin D supplementation it is possible to select the best sperm cells and thereby ensure the best chances of pregnancy," said Martin Blomberg Jensen.
The effect of vitamin D was initially tested on animal models, in which the animals either had a vitamin D deficiency or disrupted vitamin D signalling. Subsequently it was tested on humans and again a positive association was found between the number of motile sperm cells with normal appearance and the concentration of vitamin D in the blood.
330 infertile men under the microscope
"On the basis of the initial animal studies, we initiated a clinical trial in which 330 infertile men were randomized to either receive a high dosage of vitamin D or a placebo for five months in order to reveal whether vitamin D supplementation can improve semen quality and fertility potential," said Martin Blomberg Jensen.
"We now only have to wait for the final test subject to complete the study, so we hope to be able to break the code and describe the effect later this year. It is crucial to conduct placebo-controlled trials before we start giving high doses of vitamin D supplementation to infertile men. However, several of our findings, including the marker part and the use of vitamin D in connection with assisted reproduction, can already be applied at fertility clinics under controlled conditions," said Martin Blomberg Jensen.
"Our work is also a reminder about the value of combining basic molecular biological studies with clinical trials. This is especially relevant given that our initial studies have revealed several vitamin-D-regulated genes in the testicle which can be regulated with existing drugs, and we are now working with Prof. Beate Lanske from Harvard University to see whether one of these drugs can potentially be used as a new treatment option for male infertility.
Today there is no known medical treatment which in well-designed randomised trials has demonstrated improved semen quality, although several papers have shown numerous positive associations between various drugs, such as antioxidants, selen, zinc, various vitamins, etc., and semen quality. Therefore, that vitamin D seems to have a positive effect on testicular function is good news for research and infertile men.
Factors in adult life
"Male semen quality is affected by many factors, of which many are probably significant at the foetal stage, so it is likely that male infertility, like testicular cancer and other male genital malformations, is caused by poor testicular development before birth. The work carried out by Martin at the Department, however shows that factors in adult life may also play a role for semen quality. It is important to find all factors of importance, because semen quality in Danish men is at a disturbingly low level and unfortunately it is contributing to a very high incidence of fertility problems among Danish couples, where 10% of all babies are born after assisted reproductive techniques," said Prof. Anders Juul, Head of Department and Consultant at the Department of Growth and Reproduction. He continued,
"In addition to the published clinical findings, as the head of department I am proud that we can foster talented young scientists who attract international attention, who at their own initiative establish collaboration with leading international researchers, and who via this novel scientific platform are establishing a unique and world-class education programme for Danish PhD students". Martin Blomberg Jensen added,"Now we just have to go out and raise the funding to recruit skilled Danish PhD students, but this is part of the game for all Danish researchers".
Oral defence of the DMSc thesis 15 August 2014
Martin Blomberg Jensen will defend his DMSc thesis at Rigshospitalet on Friday 15 August. The thesis is entitled
Vitamin D and male reproduction,
and it has been published in the prestigious scientific journal
Nature Reviews Endocrinology.
His work is now the basis for a new collaboration within research and education between Harvard University and Rigshospitalet.Contact
Dr. Martin Blomberg Jensen
Tel.: +45 26 35 73 32 / +45 35 45 18 65
Professor Anders Juul