Human capillaries are the smallest blood vessels in the body. They are so tiny that red blood cells need to travel single file.

These small blood vessels, called microvasculature, provide every tissue in your body with a channel to deliver nutrients and oxygen, exchange hormones, and remove waste. But when these vessels are altered, harmful conditions can arise, including Alzheimer’s disease, tumor progression, diabetic blindness, and stroke.

Laura Beth Payne, a postdoctoral associate at the Fralin Biomedical Research Institute at VTC, has received a two-year American Heart Association postdoctoral fellowship to examine how two microvasculature cell types, pericytes and endothelial cells, communicate through specific molecular signals.

In healthy vessels, pericytes wrap around multiple endothelial cells, the innermost lining of blood vessels, keeping the structure stabilized and sealed tight. Part of this stability comes from the basement membrane, a specialized collagen-based layer that surrounds the vessels.

When these vessels are injured or diseased, the body attempts to repair itself. This triggers the release of a protein signal called vascular endothelial growth factor (VEGF).

“We think that in scenarios where VEGF is elevated, it leads to changes in collagen production by the vessel’s endothelial cells,” said Payne, who works in the laboratory of John Chappell, an assistant professor of biomedical engineering and mechanics at the Fralin Biomedical Research Institute’s Center for Heart and Reparative Medicine Research. “Such changes to the basement membrane affect how pericytes interact with the endothelium.”

But without pericytes, the vessel becomes unstable and leaky.

This is the same reason why after an ischemic stroke, which happens when a blockage prevents normal blood flow, it is difficult to reperfuse the damaged brain region — the microvasculature is far too delicate and can’t tolerate increased pressure.

Using lab-engineered vessels that are just a few micrometers thick, Payne and her colleagues want to gain insight into the process leading up to pericyte loss.

“If we can understand this how VEGF influences this process, then it would allow us to begin identifying molecular targets for therapeutic interventions,” said Payne.

Payne spent her childhood in Norfolk, Virginia, and received both her bachelor’s and doctoral degrees from Virginia Tech. Once the fellowship concludes in 2020, Payne plans to identify an independent faculty position at a university.

“My personal goal with this work is to help people who are suffering from vascular-related diseases by taking our discoveries at the bench to the bedside.”

Written by Whitney Slightham, assistant director of communications for the Fralin Biomedical Research Institute at VTC, and originally published by Virginia Tech News