Before the scientific advances of the modern age, getting pregnant was pretty much a hit and miss endeavor. While most pregnancies were welcome, some couples, or singles for that matter, wished they could delay things for a while due to financial or career concerns. There were also people that, no matter how hard they tried, could not conceive. The ability to safely freeze reproductive tissues and store them in biorepositories gave people more control over their reproductive lives. The following is an explanation of the procedures used in biorepositories and the three types of human tissue preserved in these "life banks."
What Is a Biorepository?
The simple explanation is that a biorepository is a facility that freezes biological specimens of all sorts. This involves the collection, processing, storage, and distribution of biological material.
Depending on the biorepository, collection is done onsite or the specimens are delivered to the facility. If collected onsite, the samples are labeled, usually with scanable bar codes that would minimize errors. If the samples are delivered, the biorepository scans the already-labeled specimens upon acceptance. Time and date of arrival are noted, as is the origin of the samples.
Processing involves the testing of each sample and preparation for the correct temperature and method of biostorage. Any item containing DNA, for example, must be placed in a watery solution that has the correct pH before freezing.
The type of freezing, and the temperature, is determined by the type of specimen. Whole blood, for example, is kept at -80 degrees Celsius and discarded if the specimen sits at 4 degrees Celsius for more than an hour. Certain items preserved for their DNA might be stored at -20 degrees Celsius, with various rules about when to refreeze and discard. Slow or fast freezing methods are used.
Distribution involves retrieval of the specimen, either for use at the biorepository or delivery to a lab or other medical setting. In the case of the frozen sperm, eggs, or embryos, the specimens could be delivered to a doctor's office or a clinic.
Three Types of Reproductive Tissues That Are Preserved in Biorepositories
Male Sperm
Biorepositories store sperm for use in artificial insemination by the donating couple or to be used by a third party couple that is having trouble conceiving. Sperm specimens are stored for at least six months before use. This gives the sperm bank time to rule out any infections carried by the donor. The sperm is put into vials and frozen in liquid nitrogen. The rapid freezing helps preserve viability. Men who develop cancer and who still want children sometimes freeze their sperm before beginning chemotherapy or radiation treatments.
Female Eggs
The collection of the eggs involves administering fertility drugs to stimulate the ovaries. Once the developing follicles are large enough, the eggs inside are harvested. This is an invasive procedure and done while the patient is sedated or under anesthesia. The harvested eggs are usually stored in liquid nitrogen, but in some cases they are placed in a protective solution and slow frozen. Eggs are typically kept for up to 10 years and may be used by the donating party, or with permission, donated to others or used in research. Women sometimes donate their own eggs if they want children closer to the middle age years. It's also an option for women in the military that want to have children, even if their reproductive organs are injured while serving in combat.
Fertilized Embryos
Fertilized embryos are often spares that were created using in-vitro fertilization, or IVF. Instead of a couple going through the process again, if the first embryo doesn't implant itself in the uterine lining, a second, or sometimes a third embryo is used. The embryos are allowed to develop for five days and are then frozen in liquid nitrogen. Just as with sperm and eggs, the rapid freezing limits damage to the embryos. This scenario alone emphasizes the need for proper labeling and storage. You do want the correct embryo to go to the correct mother-to-be.
