Wednesday, February 10, 2010

Heart Stent Research

New advances in medical research have brought heart stents to the forefront of heart health. Research is now being conducted to improve drug-eluting heart stents to reduce the risk of blood clots forming after stents are placed.

A team of researchers is testing whether coating heart stents with a human protein could prevent the re-narrowing of coronary arteries after balloon angioplasty procedures.

The project brings together scientists William Fay, a professor of internal medicine, medical pharmacology and physiology, and director of the division of cardiovascular medicine for MU; Daniel Lawrence, a professor of cardiovascular medicine at the University of Michigan; Douglas Bowles, an associate professor of biomedical sciences at MU; and Brian Wamhoff, an assistant professor of cardiovascular medicine and biomedical engineering at the University of Virginia.

A heart stent, an alternative to invasive bypass surgery, is used to reopen blocked arteries. The stents are placed after an angioplasty — a procedure in which a small balloon is fed through the femoral artery to the blocked artery and then inflated to reopen the artery.

In the past, angioplasty has been the only treatment. But in recent years, doctors have been using the balloons to place stents, which prop the artery open to keep blood flowing.

Bare-metal stents consist of wire mesh without any type of coating. This type of stent can allow the smooth muscle cells that cause arterial blockage to re-form.

“Small cells can regrow through a stent like snowflakes getting through chicken wire and building up,” Fay said.

Drug-eluting stents are coated with drugs that inhibit cells from dividing and causing re-narrowing in the cleared arteries.

"However, these drugs also inhibit the growth of the endothelial cells that coat the inner lining of blood vessels," Fay said, "which renders the artery vulnerable to blood clot formation, which can cause heart attack."

The researchers hope the human protein being studied, called plasminogen activator inhibitor 1, or PAI-1, will halt the growth of bad cells while still encouraging the good ones to grow, Fay said.
Lawrence, from the University of Michigan, has been studying PAI-1 in his lab for more than 20 years and is hopeful it can control cell growth.

The three-year PAI-1 project will be funded through a grant from the MU Life Sciences Research Trust Fund and will be carried out in two parts.

Fay and Lawrence will continue their research on PAI-1 and its effects on smooth muscle cells and the effects of drug-eluting heart stents on blocked arteries. On the other end of the project, Bowles, the associate professor of biomedical sciences for MU, will study live results of angioplasty in pigs.

Both Fay and Lawrence have worked with mice in the past. But for the studies to advance, “the subjects have to graduate and become something more akin to humans. Pigs are the closest subject for this,” Fay said.

The project has been many years in the making. It's being carried out with extreme care for humane treatment of the animals, with the help of MU's vet school, Fay said.
MU "is the only (university) in the state and one of the few in the nation where both (a medical school and veterinary medicine school) exist on the same campus,” Fay said.

Advances in medical technology aren't the only goals of the project. The researchers are hopeful the collaboration of multiple scientists across the nation will lead to the creation of more interactive research groups leading to new developments for small businesses that could provide the new technology for these projects, as well.

"We're looking beyond our own molecule," Fay said, "to serve the broader community for advancing science and technology."

http://www.columbiamissourian.com/stories/2009/03/25/drug-eluting-heart-stent-research-project-begins-mu/


This article intrigued me because it is related to the heart physiology we have recently been studying and it is something I want to focus on. This research will further advance the use of stents and bio materials. With this research invasive open heart surgery's won't be as necessary because the stents will fix the problem and the drugs will keep the arteries from re-narrowing.

Shan Murtaza Rizvi

Labels: ,

Monday, November 30, 2009

Heart and Bone Damage from Low Vitamin D Tied to Declines in Sex Hormones

Vitamin D is a known essential to keeping our bodies healthy. Sources of vitamin D can come from fortified foods and sunlight. Vitamin D is prescribed to treat osteoporosis; however, recent studies suggest it could also be useful in preventing heart disease. Such studies at Johns Hopkins found that low levels of vitamin D (considered 20 nanograms per milliliter or lower) and estrogen are independent risk factors for hardened and narrowed arteries as well as weakened bones. The relationship between vitamin D, estrogen, and testosterone have been known to influence arterial and bone health, however exactly HOW they work to do this is a mystery to many scientists.


An example of this phenomenon is long term effects of estrogen therapy in women failed to show fewer heart disease deaths, but less bone fractures. The Johns Hopkins study data was provided when they analyzed blood samples from a group of men participating in a study on cancer. This was part of an ongoing national health survey involving both men and women and was created to compare the risk of diseases between those with the lowest blood levels of vitamin D to those with higher amounts. Hormone levels in men were measured when the sex hormones were either circulating freely or when they were attached to SHBG (sex hormone binding globulin). No correlation has been made between low levels of vitamin D and low levels of hormones, however when ratios of estrogen to SHGB were compared, rates of osteoporosis were higher when the two we depressed.

This shows how important vitamin D is to good bone health, and that osteoporosis and heart disease (for men) relies heavily on vitamin D and sex hormones (estrogen particularly). Surveys showed that 41 percent of men and 53 percent of women are nutrient deficient with vitamin D. Current clinical trials are ongoing for this information in women.

http://www.sciencedaily.com/releases/2009/11/091115123715.htm

Labels: , , ,