Component of Green Tea Preserves Platelets
A major component in green tea, epigallocatechin-3-O-gaIlate (EGCG), has been found to help prolong the preservation of both stored blood platelets and stored skin tissues.
Two complimentary studies demonstrated that EGCG, known to have strong antioxidative activity, could prolong platelet cell shelf life via antiapoptosis properties, and to preserve skin tissues by controlling cell division. Scientists suggested that EGCG inhibited the activation of platelet functions and protected the surface proteins and lipids from oxidation.
Dr, Suong-Hyn Hyon, lead author on both studies and associate professor in the Institute for Frontier Medical Sciences, Kyoto University, (Japan; www.frontier.kyoto-u.ac.jp) said that EGCG, a green tea polyphenol, is a known antioxidation and antiproliferation agent, but the exact mechanism by which EGCG works is not yet known. However, some of the activity of EGCG is probably related to its surface binding ability.
Using standard blood banking procedures, the storage duration for platelet cells (PCs) is limited to five days internationally or three days in Japan. During storage, PCs undergo biochemical, structural, and functional changes, and PCs may lose membrane integrity and haemostatic functions, such as ability to aggregate and affinity for surface receptors. Thus, PC shortages frequently occur. When EGCG was added to blood platelet concentrates, aggregation and coagulation functions were sustained in an improved manner after six days.
Another team of Japanese scientists studied the effects of using EGCG on frozen, stored skin tissues. As with platelet storage, the storage of skin tissue for grafting presents problems of availability and limitations on the duration of storage. „The storage time of skin grafts was extended to 24 weeks by cryopreservation using EGCG and the survival rate was almost 100%,” noted Dr. Hyon.”
The studies appeared online in a double of Cell Transplantation in September 2009.
Image: Colored scanning electron micrograph of activated blood platelets (Photo courtesy of NIBSC).