We've all heard of sperm banks. But why not egg banks?
Human egg banks haven't been practical because freezing an egg from a woman's ovary has been nearly impossible to accomplish without damaging it. Overall success rates are only about 1 percent.
Now, a Rhode Island-based company says it has helped developed a technique for freezing eggs that protects them from being harmed during the freezing process.
"Like existing sperm banks, there can be a bank of donor eggs," said Nicholas H. Kondon, president of Gamete Technology, based in North Kingstown.
For example, a woman in Atlanta could make arrangements to have frozen eggs flown from an egg bank in Boston to her in vitro fertilization clinic, he said. The eggs could then be thawed, incubated, fertilized and finally implanted in the woman.
The technology could lower the cost of couples seeking donor eggs, and it could make it possible for a woman to harvest her eggs while she is young to make it more likely she could have a baby later.
"Cryopreservation of oocytes [human eggs] could represent a major advance in the treatment of many of the most severe fertility problems affecting women today," said Marc Beer, chair and chief executive officer of ViaCell, a Boston-based biotechnology company. ViaCell has licensed the method of egg-preservation from Gamete Technology, the two companies announced yesterday.
Scientists have long been able to freeze sperm and also freeze embryos -- fertilized eggs -- and have kept them in that state for years. But they haven't been very successful in freezing eggs alone.
The reason, according to Kondon, is that water inside the egg usually crystallizes during the freezing process, destroying the egg. Sperm are made up of mostly genetic material and can survive freezing. Embryos, which can contain many cells, can remain viable, even if some of the cells are damaged or destroyed during freezing.
Kondon says that his company has developed a technique that involves injecting a special type of sugar called trehalose into the egg. Trehalose prevents crystals from forming when frozen.
"As the temperature is rapidly lowered, the sugars acts to put the water into a glassy state," Kondon said. "No crystals are formed."
Trehalose is a naturally occurring sugar found in certain species, such as brine shrimp and arctic frogs, which can survive being frozen.
A frozen egg could easily remain viable for the lifetime of the donor, and probably much longer, Kondon said. An egg that is not frozen may last for less than 24 hours, he said.
Once it is thawed, it can be fertilized in the same fashion that traditional in vitro fertilization is performed.
Kondon said the process was developed by three researchers from Massachusetts General Hospital and Harvard Medical School -- Dr. Thomas Toth, director of the IVF Unit for Reproductive Endocrinology and Infertility at Massachusetts General, and Mehmet Toner and Ali Eroglu, also from MGH.
He learned about the research from Toth, who is married to a cousin of Kondon's,and the two of them began discussing it at a family gathering about 3 1/2 years ago.
Soon after, Kondon proposed financing the researchers' work, helping to apply for a patent, and finally licensing the technology.
Kondon has a lot of experience launching technology start-up companies. They include BruxCare, which makes a device to treat teeth-grinding; Accutek, which developed a device to assess periodontal disease; and Sweet Micro Systems, which developed a computer device for high-speed data acquisition.
Toth and the others agreed to form a company with Kondon called Gamete Technology. Kondon persuaded about 11 others to invest in the company as well.
In June, a patent was awarded for the injecting and freezing process, after eight years of development. The patent is owned by Massachusetts General, and the rights to use it belong to Gamete.
Yesterday, ViaCell announced that it had licensed the freezing technology for use in human in vitro fertilization clinics around the world. Gamete retains the rights for applications related to other human cells and all veterinary applications. Toth and Toner will serve as consultants to ViaCell, that company said.
Kondon said that the technique has been used to produce mice from frozen mouse oocytes. The company has frozen and thawed human eggs, but has not yet tried to fertilize them. The success rate for freezing and thawing what appear to be viable human eggs is about 70 percent, he said. The success rate for producing babies will be lower because of the many factors involved in fertilization, he said.
ViaCell plans to conduct clinical trials with human eggs using the technique.
"Of all the things I've done, this is the one with the greatest import," said Kondon.
"To preserve fertility for later years, to reduce the price of donor recipient programs . . . it's an important project to be involved with."
