(Statins)New test shows source of disease side-effects

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New test shows source of disease side-effects

http://www.reuters.com/article/healthNews/idUSN247722520080224?

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A new panel of tests aimed at finding out how drugs may damage cells

has turned up a series of interactions that may explain some of the

serious side-effects of statin drugs, researchers said on Sunday.

Statins, the wildly popular cholesterol-lowering drugs, may interact

with at least one blood pressure drug to damage the mitochondria, the

powerhouses of cells, the researchers reported in the journal Nature

Biotechnology.

Their study also may lead to the development of drugs to treat

diabetes and diseases of aging and better ways to screen for drug

side-effects, the researchers said.

Vamsi Mootha of the Broad Institute at Harvard University and the

Massachusetts Institute of Technology said they had made their new

database freely available to other scientists to use for screening

drugs.

The mitochondria are structures in cells that make adenosine

triphosphate, or ATP, which helps power cells. Mootha's team tested

more than 2,000 drugs on cells to see how they might interfere with

this process.

Their test looks at gene function, ATP levels and other measures of

how well the mitochondria are working.

Many patients who take statins have reported side-effects that

include muscle pain and weakness. The cause is not well understood

but Mootha has long suspected the mitochondria are involved. The

effects have been hard to pin down because studies of different

groups have produced conflicting results.

Mootha's team said their findings showed some statins lower ATP

levels and interfere with the mitochondria.

" Of the six statins present in our screening collection, three

(fluvastatin, lovastatin and simvastatin) produced strong decreases

in cellular ATP levels and (mitochondrial) activity, " they wrote.

Fluvastatin is sold by Novartis under the brand name Lescol,

lovastatin is sold under the brand name Mevacor and simvaststin is

sold as Zocor.

PATTERN OF DYSFUNCTION

Three others -- atorvastatin, made by Pfizer under the brand name

Lipitor, pravastatin or Pravachol, made by Bristol Myers Squibb and

rosuvastatin, sold under the Crestor brand name by AstraZeneca -- had

little effect, they said.

" We asked what pattern of dysfunction they cause in the

mitochondria, " Mootha said in a telephone interview. " Once we figured

out what the pattern was we asked what other FDA-approved drugs give

rise to that same pattern of mitochondrial dysfunction. "

They found a few.

" We were struck by the fact that one of these nearest-neighbor drugs

is propranolol, a widely used antihypertensive agent, " they wrote.

Propranolol is a so-called beta blocker drug sold by Wyeth under the

brand name Inderal and also available generically.

" That was a bit of a surprise, " Mootha said. " And it is important

because so many patients are on a statin as well as blood pressure

medication. "

Other drugs that resembled statins in their activity in mitochondria

included amoxapine, cyclobenzaprine, griseofulvin, pentamidine,

paclitaxel, propafenone, ethaverine, trimeprazine and amitriptyline.

A similar process may be going on in diabetes, nerve degeneration and

aging, Mootha's team said. They found a number of drugs, including

the cancer drug vinblastine may counter this process.

Mootha cautioned that his group has worked only in batches of muscle

cells grown in the lab so far and that far more tests are needed.