Viagra Shows New Potential To Prevent Clots

The
cellular response to Viagra may be harnessed to help create new
anticoagulant therapies, according to an article released on August 26,
2008 in the Proceedings of the National Academy of Sciences
(PNAS.)



The
enzyme PDE5 is known to modulate platelet activity. Normally, platelets
exist in the blood and have an integral role in blood clotting.
However, when patient have certain biomedical devices implanted, such
as stents, which are installed in the arteries to maintain blood flow
through them, the foreign materials of the devices , are recognized by
the body and platelets often clot to them. If too many clot, this can
block blood flow, potentially inducing a stroke or heart attack.



While
Viagra is most famous for its use in treatment of erectile dysfunction,
it was initially targeted as a drug for the cardiovascular system as a
whole and is also used to treat pulmonary hypertension in some
patients. Drugs like Viagra have been previously shown to inhibit PDE5,
but further research was necessary to understand where or how this was
occurring.



This study, led by Prof. Donald Maurice of Queen's
College focused on the relationship between Viagra and the levels of
PDE5 inhibition in cells. They showed that, within each cell, several
pools of the PDE5 enzyme may exist. However, only one of these pools
might regulate platelet activation. By targeting each pool, it may be
possible to revamp Viagra's use to regulate clotting in the blood,
helping prevent heart attacks and strokes. "Understanding how the cell
works should allow us to affect the activity
of enzymes in one neighborhood -- and leave alone their 'identical
twins' in a different neighborhood in that cell," says Ms. Wilson, lead
author on the study.



The
authors note the potential that arises from these developments, both in
basic and clinical science. "As scientists, we're excited about this
discovery because it's a
fundamentally new approach to regulating what enzymes do in cells,"
states Dr. Maurice. "The fact that it also offers a potentially novel
use of a
drug already widely in use for other applications is an unexpected
bonus." Ms. Wilson continues, hopeful for the potential application of
this new knowledge: "The idea is to use a PDE5 inhibitor such as Viagra
selectively to
inhibit platelet function. We now know that not all the
enzymes in the cell are doing the same job. Just like in real estate,
it's all about the location!"



Tuesday August 26, 2008

Proceedings of the National Academy of Sciences

Click Here for Journal



Written by Anna Sophia McKenney



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