Long-Term Use of Ventricular Assist Devices Induces Heart Muscle Regeneration, Study Finds

Posted: January 21, 2015 at 8:49 pm

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Newswise DALLAS January 21, 2015 Prolonged use of a left ventricular assist device (LVAD) by patients with heart failure may induce regeneration of heart muscle by preventing oxidative damage to a cell-regulator mechanism, UTSouthwestern Medical Center investigators have found.

LVADs are mechanical pumps that are sometimes implanted in patients who are awaiting heart transplants. LVADs substitute for the damaged heart by pumping blood throughout the body.

Dr. Hesham Sadek, Assistant Professor of Internal Medicine at UTSouthwestern, is senior author of the study, which looked at pre- and post-LVAD samples of heart muscle in 10 patients with heart failure. The study authors examined the paired tissue samples for markers of DNA damage and cell proliferation.

Their study builds on earlier work with mice that demonstrated that newborn mammalian hearts are capable of a strong, regenerative response to injury by activating cell division. The earlier studies further showed that the ability to respond to injury is lost due to changes in circulation that occur after birth, which lead to a more oxygenated environment in the heart, ultimately causing oxidative damage to the cellular machinery that controls heart-muscle regeneration.

In the current study, the investigators reasoned that, by assisting the damaged heart, LVADs would alleviate oxidative damage that occurs within the heart-muscle cells.

We looked at markers of what is called the DNA damage response in cardiomyocytes (heart-muscle cells) of these patients, said Dr. Sadek. The response is composed of a cascade of proteins that is activated in response to DNA damage and in turn shuts off the ability of cardiomyocytes to divide. We found that patients who were on LVAD for more than six months had significantly decreased levels of DNA damage response.

Next, the investigators examined the paired tissue samples for markers of cell division. They found that patients who were on LVADs for six months or longer had a significant increase in cardiomyocyte proliferation. The increase in cell proliferation was nearly triple, in fact.

This result shows that patients with mechanical assist devices have the ability to make their muscle cells divide, said Dr. Sadek. And the obvious question now is, Are these hearts regenerating? Could LVADs be used as a cure for heart failure?

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Long-Term Use of Ventricular Assist Devices Induces Heart Muscle Regeneration, Study Finds

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