Component Of Green Tea Protects Injured Livers In Mice

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Component Of Green Tea Protects Injured Livers In Mice

A new study investigating the effects of the major flavonoid component

of green tea on hepatic steatosis (fatty liver) found that it

significantly protected livers that suffered ischemia/reperfusion (I/R)

injury in mice. I/R injury, which is caused by decreased blood flow,

can lead to complications after liver transplantation.

The results of this study appear in the March 2005 issue of Liver

Transplantation, the official journal of the American Association for

the Study of Liver Diseases (AASLD) and the International Liver

Transplantation Society (ILTS). The journal is published on behalf of

the societies by Wiley & Sons, Inc. and is available online via

Wiley InterScience at

http://www.interscience.wiley.com/journal/livertransplantation.

Approximately one-fifth of the U.S. population is afflicted with

hepatic steatosis due to a rising incidence of obesity. Because fatty

livers are more sensitive than lean livers to I/R injury and are

associated with an increased risk of disease and death, this has

resulted in fewer usable donors for liver transplants. In fact, nearly

one-third of all donated livers are afflicted with fatty changes, but

longer waiting lists are forcing practitioners to consider using these

organs. A previous study found that rinsing livers with a solution

containing green tea extract prevented failures in transplants using

fatty livers. The current study examined whether

(-)-epigallocatechin-3-gallate (EGCG), the major flavonoid component

found in green tea, protected fatty livers from cell damage after I/R

injury.

Led by D. Chavin, M.D., Ph.D., of the Medical University of

South Carolina in ton, SC, researchers administered EGCG either

orally or by injection and performed surgery to induce I/R injury in

mice; control groups did not receive the EGCG. Mice receiving EGCG by

either method showed a survival rate of 100 percent, versus 65 percent

for the controls. Tissue analysis showed that the EGCG mice had

decreased necrosis (cell death) and a higher percentage of viable

tissue, demonstrating that the flavonoid protected the liver from I/R

injury.

The next step was to determine the mechanism by which EGCG protected

fatty liver cells from I/R injury. Researchers developed a technique to

measure fatty acids and found that levels of palmitic and linoleic

acid, two fatty acids that are present in large amounts in fatty

livers, decreased significantly in EGCG treated mice. Further tests

revealed an increase in hepatic energy stores (one of the liver's

functions is to store energy in the form of glycogen) in EGCG mice and

showed that EGCG was acting as an antioxidant, thereby protecting fatty

livers from I/R injury. In addition, the study showed that EGCG reduced

liver fat content by approximately 55 percent. " Significant differences

to the fat content, energy stores and markers of cellular injury were

observed regardless of how the compound was administered, " the authors

note.

The authors conclude that " the data presented here indicates that EGCG

protects the steatotic liver from I/R injury by reducing hepatic fat

content, increasing energy stores, serving as an antioxidant and may

stimulate the production of additional antioxidants such as GSH. " They

add that these activities warrant further investigation and that a

thorough understanding of how ECGC acts may suggest its use as a

therapeutic agent for fatty livers used in liver transplants.

http://www.sciencedaily.com/releases/2005/02/050223151300.htm

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