Researchers to conduct a series of studies on human circulation

Penn State College of Medicine researchers recently were awarded a five-year, $7 million grant from the National Heart, Lung and Blood Institute of the National Institutes of Health to conduct a series of studies on human circulation.

“Our goal is to gain a better understanding of how blood circulates in the body and how the bundles of nerves and nerve cells controlling many functions in the body help to regulate blood flow,” said Lawrence I. Sinoway, principal investigator for the grant, professor of medicine in the Penn State College of Medicine and program director in the Penn State General Clinical Research Center (GCRC). “Ultimately, this work may lead to new treatments for high blood pressure, heart failure and heart disease, and help to explain other mysteries of cardiovascular health.”

The grant will fund three projects. The first project, led by Sinoway, will examine the exercise pressor reflex, a communication mechanism between the brain and cardiovascular system active during exercise. Sinoway will compare the pressor reflex in healthy volunteers to people with heart failure, a disease affecting about 5 million Americans in which the heart weakens and has a reduced ability to pump blood. Information gained through his studies could lead to therapies to improve mobility and fitness for those with heart failure.

A second project will be led by Urs Leuenberger, professor of medicine in the Penn State College of Medicine and associate program director in the GCRC. His studies will examine how the nerves supplying the walls of the blood vessels and chemical factors produced in the body influence blood flow in response to hypoxia, a lower than normal blood oxygen level. Hypoxia commonly accompanies a variety of diseases of the heart and lungs. Through a finely-tuned interaction between nerve signals and chemical factors, hypoxia normally causes a rise in blood flow to skeletal muscle that helps maintain the supply of badly-needed oxygen. These studies could lead to information that may one day help physicians better treat conditions in which blood flow is not properly regulated.

A third project, led by Chester A. Ray, professor of medicine and cellular and molecular physiology in the Penn State College of Medicine, will study how the nervous system’s control of blood vessel function reacts to messages from the vestibular system in the inner ear, which gives the body information on head position, movement and balance. Ray will study exercise-conditioned athletes and patients with orthostatic intolerance, an unexplained inability to maintain blood pressure while standing. His studies could lead to new knowledge about and therapies for those with orthostatic intolerance who become dizzy or faint when standing. Due to physiological changes in microgravity, astronauts, too, develop orthostatic intolerance when returning from missions in space. This inability to stand up can pose a hazard to astronauts in emergency evacuations.

A unique feature of this award is that all projects involve studies in humans. Such studies would not be possible without Penn State’s GCRC, which provides a centralized place for clinical researchers to meet with patients who take part in clinical investigations. At the GCRC, researchers share staffing and specially-equipped space and have access to facilities for sample and data processing. GCRC staff help investigators with recruitment and provide other support for clinical studies. Sharing allows investigators to save money on facilities and staffing and allocate their limited grant resources to other aspects of their research projects. At present, more than 150 clinical investigations are under way. Penn State is one of only 80 such funded centers in the United States.