Body tissues such as blood vessels, cartilage and skin—even whole organs such as kidneys, livers and hearts—could become more widely available for transplants as a result of a patent issued recently to Organ Recovery Systems of Chicago for a method to chill body tissues and organs well below freezing without forming ice crystals. The new process for tissue "vitrification"—chilling tissue and organs to a disordered, glass-like solid without ice formation—was developed with support from the National Institute of Standards and Technology (NIST) Advanced Technology Program and the National Institutes of Health.
There is an urgent need for tissues and organs for transplantation. Doctors conducted over 24,000 organ transplants in the United States in 2002; yet someone is added to the donor waiting list every 12 minutes and 16 people die each day waiting for an organ transplant. A significant roadblock to the broader use of transplantation, regardless of the source (donated human, cross-species or artificial), has been the problem of preserving the transplant tissue. Better preservation techniques would allow transplant materials to be shipped anywhere in the world or, better yet, collected and stored in something akin to blood banks until needed.
Organs and some tissues are presently stored for short periods at refrigerator temperatures (approximately 4 °C) and freezing has not been possible due to ice crystals, which damage delicate cells and greatly reduce the viability or functions of the tissue. Chemicals called cryoprotectants reduce ice formation but have toxic effects that introduce their own problems. The Organ Recovery Systems technique combines a mixture of cryoprotectant compounds that cancel each other’s toxicity and careful control of the cooling and warming processes to minimize damage to the tissue. The technique is discussed in U.S. patent no. 6,740,484. (Patent text available at http://www.uspto.gov.)
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