Findings on the protective qualities of H2S have broad
implications for improving human survival after cardiac arrest, heart
transplant and trauma in general, said David Kraus, Ph.D., a UAB
associate professor in the Departments of Environmental Health
Sciences and Biology and co-author on the new study.
�One of the most damaging biological stresses on the heart and other
organs from trauma or transplantation is the rapid change in oxygen
levels,� Kraus said. �First there�s a drop, which elicits a dramatic
cellular adjustment to survive low oxygen, and then a rapid rise
caused by resuscitation.
�H2S as an internal bodily signal appears to serve as an
important protective mechanism during the stress of low oxygen
availability,� he said.
The study was published Sept. 18 in the online Early Edition of the
journal Proceedings of the National Academy of Sciences. The UAB
researchers worked with a team led by David Lefer, Ph.D. from the
Albert Einstein College of Medicine in Bronx, N.Y.
The tests were done by injecting H2S directly into the
hearts of mice who had been anesthetized for surgery, and whose left
ventricular artery had been clamped for 30 minutes to simulate a heart
attack.
In addition to a decrease in heart-tissue death, H2S-treated
mice hearts showed a 35 percent drop in blood-protein levels that
signal myocardial damage, and a 26 percent drop in heart-tissue
markers of inflammation when compared to un-treated mice hearts.
Furthermore, by isolating mitochondria from the H2S-treated mice, the
authors confirmed that heart-cell functional integrity had been
preserved. Recent reports from other researchers demonstrate that
inhaled H2S can induce a fully reversible �suspended
animation� state in animals.
Kraus said it follows that H2S could be used to place
organs into �suspended animation� before surgery or during medical
transport until normal oxygen and blood flow is restored. Also, by
augmenting internal H2S production in the body, perhaps
through diet, people may reduce their risks of cardiovascular disease,
chronic oxidative cell damage and other illnesses, Kraus said.
H2S is normally considered a toxic, flammable gas that is
responsible for the foul odor of rotten eggs. But in the UAB study it
was carefully formulated into a low concentration saline-type solution.
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