Vitamin D: New way to treat heart failure?

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Public release date: 11-Jun-2008

http://www.eurekalert.org/pub_releases/2008-06/uomh-vdn061108.php

Contact: Anne Rueter

arueter@...

University of Michigan Health System

Vitamin D: New way to treat heart failure?

http://www.eurekalert.org/pub_releases/2008-06/uomh-vdn061108.php

U-M scientists show vitamin D treatments prevent heart failure damage in

animal study

Heart muscle cells in untreated rats bred to develop heart failure show

signs of disease. Right: Heart muscle cells remain healthy in rats

treated with calcitriol, the hormone that Vitamin...

Click here for more information.

ANN ARBOR, Mich. — Strong bones, a healthy immune system, protection

against some types of cancer: Recent studies suggest there's yet another

item for the expanding list of vitamin D benefits. Vitamin D, " the

sunshine vitamin, " keeps the heart, the body's long-distance runner, fit

for life's demands.

University of Michigan pharmacologist U. Simpson, Ph.D., thinks

it's apt to call vitamin D " the heart tranquilizer. "

In studies in rats, Simpson and his team report the first concrete

evidence that treatment with activated vitamin D can protect against

heart failure. Their results appear online ahead of print in the Journal

of Cardiovascular Pharmacology.

In the study, treatments with activated vitamin D prevented heart muscle

cells from growing bigger – the condition, called hypertrophy, in which

the heart becomes enlarged and overworked in people with heart failure.

The treatments prevented heart muscle cells from the over-stimulation

and increased contractions associated with the progression of heart failure.

About 5.3 million Americans have heart failure, a progressive, disabling

condition in which the heart becomes enlarged as it is forced to work

harder and harder, making it a challenge even to perform normal daily

activities. Many people with heart disease or poorly controlled high

blood pressure go on to experience a form of heart failure called

congestive heart failure, in which the heart's inability to pump blood

around the body causes weakness and fluid build-up in lungs and limbs.

Many people with heart failure, who tend to be older, have been found to

be deficient in vitamin D.

" Heart failure will progress despite the best medications, " says

Simpson, a professor of pharmacology at the U-M Medical School. " We

think vitamin D retards that progression and protects the heart. "

The U-M researchers wanted to show whether a form of vitamin D could

have beneficial effects on hearts that have developed or are at risk of

developing heart failure. They used a breed of laboratory rats

predisposed to develop human-like heart failure.

The researchers measured the effects of activated vitamin D (1,25

dihydroxyvitamin D3, a form called calcitriol) in rats given a normal

diet or a high-salt diet, compared to control group rats given either of

the same two diets, but no vitamin D treatment. The rats on the

high-salt diet were likely to develop heart failure within months.

The rats on the high-salt diet, comparable to the fast food that many

humans feast on, quickly revealed the difference vitamin D could make.

" From these animals, we have obtained exciting and very important

results, " Simpson says.

After 13 weeks, the researchers found that the heart failure-prone rats

on the high-salt diet that were given the calcitriol treatment had

significantly lower levels of several key indicators of heart failure

than the untreated high-salt diet rats in the study. The treated rats

had lower heart weight. Also, the left ventricles of the treated rats'

hearts were smaller and their hearts worked less for each beat while

blood pressure was maintained, indicating that their heart function did

not deteriorate as it did in the untreated rats. Decreased heart weight,

meaning that enlargement was not occurring, also showed up in the

treated rats fed a normal diet, compared to their untreated counterparts.

Simpson and his colleagues have explored vitamin D's effects on heart

muscle and the cardiovascular system for more than 20 years. In 1987,

when Simpson showed the link between vitamin D and heart health, the

idea seemed far-fetched and research funding was scarce. Now, a number

of studies worldwide attest to the vitamin D-heart health link (see

citations below).

The new heart insights add to the growing awareness that widespread

vitamin D deficiency—thought to affect one-third to one-half of U.S.

adults middle-aged and older—may be putting people at greater risk of

many common diseases. Pharmaceutical companies are developing

anti-cancer drugs using vitamin D analogs, which are synthetic compounds

that produce vitamin D's effects. There's also increasing interest in

using vitamin D or its analogs to treat autoimmune disorders.

In more than a dozen types of tissues and cells in the body, activated

vitamin D acts as a powerful hormone, regulating expression of essential

genes and rapidly activating already expressed enzymes and proteins. In

the heart, Simpson's team has revealed precisely how activated vitamin D

connects with specific vitamin D receptors and produces its calming,

protective effects. Those results appeared in the February issue of

Endocrinology.

Sunlight causes the skin to make activated vitamin D. People also get

vitamin D from certain foods and vitamin D supplements. Taking vitamin D

supplements and for many people, getting sun exposure in safe ways, are

certainly good options for people who want to keep their hearts healthy.

But people with heart failure or at risk of heart failure will likely

need a drug made of a compound or analog of vitamin D that will more

powerfully produce vitamin D's effects in the heart if they are to see

improvement in their symptoms, Simpson says.

Vitamin D analogs already are on the market for some conditions. One

present drawback of these compounds is that they tend to increase blood

calcium to undesirable levels. Simpson's lab is conducting studies of a

specific analog which may be less toxic, so efforts to develop a vitamin

D-based drug to treat heart failure are moving a step closer to initial

trials in people.

###

In addition to Simpson, other U-M authors include Mancuso, Ph.D.,

of the U-M Department of Environmental Health Sciences; Ayesha Rahman,

Ph.D., D. Hershey, M.D., Loredana Dandu and Karl A. Nibbelink,

M.D. of the Department of Pharmacology in the U-M Medical School.

Funding for the study came from the National Institutes of Health.

Patents related to this research have been applied for by the U-M Office

of Technology Transfer.

Citations: Journal of Cardiovascular Pharmacology,

jcardiovascularpharm.com, 10.1097/FJC.0b013e3181761906

Endocrinology, 2008, 149 (2), 558-564.

On the web: Images and journal article available at

http://www2.med.umich.edu/prmc/media/newsroom/details.cfm?ID=334

Background at http://www.med.umich.edu/opm/newspage/2008/chf.htm

http://www.med.umich.edu/opm/newspage/2004/hmvitamind.htm

--

ne Holden, MS, RD

" Ask the Parkinson Dietitian " http://www.parkinson.org/

" Eat well, stay well with Parkinson's disease "

" Parkinson's disease: Guidelines for Medical Nutrition Therapy "

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