Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dartmouth study suggests caution against using certain drugs to unclog heart arteries

12.10.2004


Dartmouth Medical School cardiology researchers have discovered a new mechanism for what drives the growth of muscle tissue in the lining of injured heart vessels that can eventually lead to blockage. Their study, reported in the October 19 issue of the journal Circulation, raises important questions about the use of drugs that promote or prevent angiogenesis - the formation of blood vessels - to treat the condition.



Normal heart arteries have a muscle tissue layer inside their walls. In coronary artery disease or in response to mechanical injury such as angioplasty (a non-surgical procedure to open clogged arteries), new smooth muscle cells grow along the innermost layer of the arterial lining and leads to narrowing. Such muscle buildup also occurs with use of a stent – a small wire mesh tube inserted after angioplasty to keep the artery clear.

It is the most common cause of stent failure, according to Michael Simons, professor of medicine and of pharmacology and toxicology at Dartmouth Medical School and chief of cardiology at Dartmouth-Hitchcock Medical Center, who headed the research team. Based on the research, Simons cautions against using angiogenic drugs to unblock arteries in certain heart conditions. He indicated that stents coated with agents that specifically target smooth muscle to prevent or kill growth should remain the treatment of choice at present. "They are not perfect, so everyone is looking for what can be added to make things better," he noted.


The biological drivers of the smooth muscle accumulation are unclear. Injury may somehow alter the tissue on the inner arterial layer, called the intima, so it is susceptible to factors in the blood that induce smooth muscle cells to proliferate. At the same time, there is an intense inflammatory response on the outermost layer of the arterial wall that also appears to be involved in stimulating blood vessels to feed smooth muscle accumulation.

Recent studies of the angiogenesis process have provided new insights into understanding cardiovascular disorders. Regulating angiogenesis with agents that promote or prevent blood vessel growth is considered a promising approach for treating a number of diseases. The researchers found that injured arteries grow smooth muscle in two distinct ways: one that depends on angiogenesis and another that is independent. "So even if no there is no angiogenesis, mechanical injury alone will still stimulate smooth muscle growth," Simons said.

This duality could make both angiogenesis-promoting and angiogenesis-suppressing drugs ineffective in preventing renarrowing of arteries following angioplasty or stenting. "In fact, pro-angiogenic drugs could make things worse, not better," Simons said. "If you’re going to use an angiogenic agent, it will do harm, because it will actually promote stenosis [narrowing] instead of inhibiting it."

The studies were done in rabbits, chosen for their thick human-like arteries. Using an agent to stimulate angiogenesis on the outer surface after local injury, the researchers found a large increase in smooth muscle in the inside lining of the artery, meaning that angiogenesis induced intimal growth that narrowed the blood vessel. Then, using different agents to inhibit angiogenesis, they showed that even when angiogenesis was completely stopped, some new muscle accumulated.

"Intimal growth is a fundamental pathology responsible for many cardiovascular diseases including atherosclerosis and hypertension," Simons said. "This is the first time such a combination of angiogenesis-dependent and independent phases of smooth muscle growth has been proposed."

Study co-authors are Dr. Rohit Khurana, who was a visiting Fulbright scholar from University College London, Dr. Zhenwu Zhuang, Dr. Masahiro Murakami, and Dr. Ebo De Muinck, all from Dartmouth Medical School, as well as colleagues from London, Finland and Genentech of San Francisco.

Andrew Nordhoff | EurekAlert!
Further information:
http://www.dartmouth.edu

More articles from Studies and Analyses:

nachricht WAKE-UP provides new treatment option for stroke patients | International study led by UKE
17.05.2018 | Universitätsklinikum Hamburg-Eppendorf

nachricht First form of therapy for childhood dementia CLN2 developed
25.04.2018 | Universitätsklinikum Hamburg-Eppendorf

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>