Men tend to be especially sensitive about their testes, so they might understandably wince at new research from Europe that aims to extract sperm-producing stem cells found in the testicles and grow them into mature sperm in the laboratory. The research is primarily intended to restore fertility in young men undergoing cancer treatment, but it could also provide an ideal test environment for drugs and compounds that might affect sperm production.
Scientists from the Netherlands reported last month that they had successfully harvested spermatogonial stem cells from cows and cultured them inside mouse testes. The researchers hope that future work will enable them to do the same thing for men. "This is a very promising route to help young cancer patients undergoing chemotherapy," said Dirk de Rooij, of Utrecht University.
The researchers indicated that they found abundant bovine spermatogonial stem cells thriving in the mouse testes after implantation. Despite the foreign surroundings, the bovine cells survived for long periods (up to three months), although de Rooij conceded that they failed to fully develop into sperm. Although not completely successful, de Rooij is, ahem, bullish about the future, with a stated plan to develop a working culture system for spermatogonial stem cells. Other researchers are impressed at the longevity achieved. "It is truly remarkable that mouse testes can sustain these bovine cells in culture," commented Elaine Dzierzak, from Erasmus University Medical Centre in Rotterdam.
Meanwhile, at the University of Helsinki in Finland, scientists have been working with a brain cell growth factor - glial cell derived neurotrophic factor (GDNF) - that appears to have a powerful influence on spermatogonial stem cells. Mice that have been genetically manipulated to express high levels of GDNF in the testes produce huge clusters of spermatogonial stem cells. But unfortunately, the risk of cancer is boosted too, so the GDNF "tap" can't be turned on indiscriminately. "We'd like to know how to culture human spermatogenic stem cells to restore male fertility after cancer therapy," said researcher Hannu Sariola, from the University of Helsinki.
The Dutch researchers have also reported success with GDNF, and additionally, are working with fibroblast growth factor (FGF), which also seems to enhance cell growth. The Dutch team's next move is to transplant monkey and human cells into the mouse testes system.
Source: European Science Foundation
