Dr. Song, whose research lab is in MCG’s biotech incubator, has developed cryoprotectants that can be used safely in higher doses as well as agents to help protect tissue during the ultra-rapid process of de-vitrification.
“People use low concentrations of cryoprotection because they are toxic,” he says. “The problem is, if you use lower concentrations, you cannot get true vitrification.” The agents are needed to intercept water so it won’t form ice. Interestingly if small ice crystals form during cooling, they can get larger during de-vitrification, which takes place in seconds.
“We developed a solution where we can warm up tissue in under five minutes and still get no ice formation,” says Dr. Song, adding that ice formation aside, it is difficult to thaw rock-solid tissue at room temperature in a matter of seconds, meaning the current approach could have extremely limited use.
A study he published in March 2000 in Nature Biotechnology showed the approach he uses works well, at least in blood vessels. “Now we want to try this on eggs and ovarian tissue and see if we can develop a robust technology and improve outcomes,” Dr. Song says.
Later, researchers will put ovarian tissue preserved both ways into mice to see if it survives and starts making proper connections.
“The reason for using ovaries is when you have cancer, if you need chemotherapy, you often don’t have time to go through stimulation cycles to get oocytes,” says Dr. Emmi. “You are concentrating on getting rid of cancer cells.” Also, if a woman has breast cancer, for example, hormones needed to induce ovulation could be problematic because many breast cancer cells have estrogen receptors.
As pieces of a puzzle come together, Dr. Song notes scientists already are developing methods to stimulate ovarian tissue to produce eggs outside the body, a process that could also make in vitro fertilization a lot more afford
Source:Medical College of Georgia