More Evidence for
Free Radical Theory of
A study published online on May 5, 2005 in the journal Science reports the finding of researchers at the University of Washington and other
centers of a way to significantly extend the lifespan of laboratory animals
while reducing the effects of aging.
University of Washington School of Medicine
professor of pathology Dr. Peter Rabinovitch and colleagues studied mice bred to
produce human catalase, the enzyme that converts hydrogen peroxide into water
and oxygen. Hydrogen peroxide is produced during metabolism and is a precursor
of free radicals that lead to cell damage, which causes the generation of even
more free radicals. The team targeted delivery of the catalase to the cytoplasm
of the cell where catalase normally decomposes hydrogen peroxide, the nucleus,
which is the center of the cell, and the mitochondrion, which are the cells
energy producing organelles.
While mice with elevated catalase levels in the
nucleus and cytoplasm experienced small increases in lifespan, animals that
produced catalase in their mitochondria were found to experience a 20 percent
increase in average and maximum lifespan and had healthier heart tissue. This
adds credence to the theory that the mitochondria are a major source of free
radicals generated as a byproduct of energy production.