Researcher investigating the role of smooth muscle in cardiovascular disease

Cardiovascular disease (CVDs) is the leading cause of death in Canada, accounting for almost half of all deaths each year. Globally, four out of five cardiovascular deaths are caused by heart attacks and strokes and one-third of these are in people under 70 years of age, according to the World Health Organization. 

Numerous factors contribute to the risk of developing CVDs. Libin Cardiovascular Institute researcher Dr. Xi-Long Zheng, PhD, focuses on the role smooth muscle plays in this process.

The body has three types of muscle cells: skeletal, cardiac and smooth muscles. The smooth muscles line the walls of hollow organ systems, such as the blood vessels, gastrointestinal tract and bladder. Smooth muscles help maintain proper organ shape and are involved in numerous automatic processes in the body, including moving the blood through the vessels in the body.

Unlike the other types of muscle cells, smooth muscle cells can change over time, becoming dysfunctional and causing adverse symptoms in individuals.

For example, if the smooth muscles that line the blood vessels contract too much, individuals can experience high blood pressure. An overgrowth of smooth muscle cells can cause a thickening and hardening of the blood vessel wall, a condition called atherosclerosis. Both conditions substantially increase the risk of heart attacks and strokes.

Dysfunction in the smooth muscle cells of the vascular system occur with aging, but there are other contributing factors, like high cholesterol. Zheng’s research focuses on trying to understand how the smooth muscle cells become dysfunctional—and looking for novel therapies—with the goal of helping patients.

One of Zheng’s project looks at how the cell’s process of cleaning up dysfunctional proteins (autophagy) impacts vascular disease.

“Because this process (autophagy) was only recently discovered, this is novel research,” says Zheng. “We are interested in how autophagy contributes to vascular stiffening and hardening. Our goal is to develop a treatment for vascular disease, vascular stiffening and hardening.”

Another project in the lab is investigating the impact of cannabis use on the vascular system.

Zheng’s research interests stem from his clinical background. He earned a medical degree at China’s Hunan Medical University in 1983. He went on to become a cardiologist and practiced in this area for about three and a half years while simultaneously working on his master’s of science degree.  

“I always think of our research in relation to the clinical setting,” says Zheng. “Our main goal is to make vascular research more translatable to patients. We want to develop new therapies to patients.”

Zheng moved to Calgary in 1993 to pursue his PhD at the University of Calgary. He completed two postdoctoral fellowships. The first was at New York State University with Dr. Craig Malon and the second was at the University of Calgary under the supervision of Dr. Norman Wong, PhD.

He started his faculty position at the University of Calgary in 2001 and has maintained an active lab for 20 years. To learn more about Zheng’s research, view his publications on his ResearchGate profile.

Dr. Xi-Long Zheng, PhD, is a professor in the Department of Biochemistry and Molecular Biology at the Cumming School of Medicine. He is a member of the Libin Cardiovascular Institute and the Arnie Charbonneau Cancer Institute.