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Gene In Kidney May Predispose You To Heart Disease January 23, 2011

Posted by Metabiological in Longevity, Transhumanism.
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Next up in our series “Nature is COMPLICATED” (there is no series, I just made that up) a study out of the NIH has for the first time found a gene variant in the population that actually seems to cause heart disease.  The kicker?  The gene in question is not even expressed in your heart.

The unexpected results highlight the advantage of performing genome-wide studies to find DNA sequence variants associated with disease.

“I was surprised by the finding,” says Thomas P. Cappola, MD, assistant professor of medicine at the University of Pennsylvania School of Medicine, also a lead investigator on the study. “This is a good example of how taking unbiased approaches to study human disease can lead you to unexpected targets.”

Studying three groups of Caucasian patients with heart failure, they found one DNA sequence variant that was common in all the groups and was actively involved in making an important protein for the body. A single change in the DNA sequence of a gene called CLCNKA leads to a change from arginine to glycine in the 83rd amino acid of the protein. This protein makes up part of a kidney channel responsible for controlling the secretion of chloride ions into the urine, an important process in maintaining the proper balance of salt and water in the body.

That single amino acid change reduced the channel’s ability to shuttle chloride ions across the cell membrane by about half. Dorn hypothesizes that a result of this reduction could be elevated levels of a hormone called renin in the blood. Renin is produced in the kidney and is the first signal in a cascade that can damage the heart. This opens the possibility of helping people who have the variant reduce their risk of heart failure with drugs commonly used to treat high blood pressure, including ACE-inhibitors and aldosterone blockers.

Interesting for a few reasons.  One is obvious, this study has the potential to lead to novel treatments for reducing the risk of heart disease, which as the number one killer in America is something we desperately need to do.  It’s simple utilitarian calculation; reducing risk will not only reduce or eliminate the suffering on those who would other wise have contracted heart disease but will also work to reduce health care costs and ease the burden said costs are placing on society at large.

Second, and more relevant to this blog, it showcases one of the difficulties we face in attempting to increase human longevity.  Namely, nature is COMPLICATED and our bodies are no exception.  As Neil Shubin put it the human body is essentially a retrofitted fish and regardless of how far we’ve come in our evolutionary history we are still bound by that ancestral framework.  As such, attempting to artificially lengthen the human lifespan by figuring out which gene does what and tweaking it appropriately is going to be absurdly difficult.  What once coded for scales may now code for skin and a single gene may do multiple things depending on when and how it is expressed.

This is why Aubrey deGrey’s SENS approach makes a lot of sense, cleaning up the damage of aging rather than attempting to fix the underlying causes.  Whether it ends up working or not is of course another story since no matter what we do we can’t escape the fact that biological life is messy.

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