University of Texas at Austin researchers have demonstrated a new and more effective method for regrowing blood vessels in the heart and limbs - a research advancement that could have major implications for how we treat heart disease, the leading cause of death in the Western world.
The treatment method developed by Cockrell School of Engineering Assistant Professor Aaron Baker could allow doctors to bypass surgery and instead repair damaged blood vessels simply by injecting a lipid-incased substance into a patient. Once inside the body, the substance stimulates cell growth and spurs the growth of new blood vessels from pre-existing ones.
The method has been tested successfully on rats, and findings of the study were published recently in the Proceedings of the National Academy of Sciences.
“Others have tried using growth factors to stimulate vessel growth in clinical trials and have not been successful,” said Baker, a faculty member in the school’s Department of Biomedical Engineering. “We think that a major reason for this is that previous methods assumed the diseased tissues retained the ability to respond to a growth stimulus. Our method basically delivers extra components that can restore growth factor responsiveness to the tissue of patients with long-standing clinical disease.”
The ability to regrow blood vessels could prove crucial to treating chronic myocardial ischemia disease, which affects up to 27 million patients in the U.S. and leads to a reduction of blood flow in the heart and lower limbs - ultimately, causing organ dysfunction and failure.
Central ischemia, which effects the heart, occurs when the coronary vessels that feed blood to the heart become blocked or narrow due to a buildup of fatty deposits, or plaques. Such plaques are typically the result of a prolonged unhealthy diet or smoking, and factors like age, high blood pressure and diabetes increase the risks of the disease, Baker said.
Heart disease is the number one killer in the United States. But one professor at the University of Pittsburgh might soon mend broken hearts, is the most literal sense anyway. Pittsburgh professor Yadong Wang figured out that by delivering a critical growth factor directly to the blood vessels in a non-invasive way, he could potentially eliminate the need for open-heart surgery someday.
So far, the treatment has worked in the lab only in animal studies. When researchers injected a growth factor under the skin of mice, the blood vessels began to regrow.
“We had structures that resembled arterioles - small arteries that lead to a network of capillaries,” Wang said in a statement.
The fact that the blood vessels showed signs of repair is significant because currently once tissue is damaged after a heart attack, a patient has to either get a stent or have bypass surgery.
Being able to repair damaged tissue and prevent further scarring, would enable doctors to keep the heart muscles alive and restore the environment that will help blood vessels grow.
Doctors have typically treated ischemia by physically opening the closed artery with a stent or surgically rerouting blood flow to the poorly perfused tissue. Both methods have limitations, however, and are not effective long-term.
The new method introduced by Baker and his research team builds off of a promising revascularization approach that, up until now, has shown limited efficacy in clinical trials for treating human disease.
The method combines a growth factor - a substance capable of stimulating cellular growth, proliferation and cellular differentiation, as well as healing wounds — known as fibroblast growth factor 2 (FGF-2) with a lipid-embedded receptor to enhance its activity.