Researcher Using Latest Technology to Study Adult Stem Cells’ Ability to Repair Blood Vessels Damaged by the Disease
PHOENIX - Cardiologist David Simper, MD, is carefully growing stem cells in his laboratory at the Carl T. Hayden VA Medical Center, watching over them like a protective parent in the hopes that they will help unlock the secret to repairing or preventing deadly complications suffered by people with diabetes.
Dr. Simper is relying on the stem cells, taken from blood samples provided by healthy adults and those with type 1 diabetes, to reveal differences in their ability to form new blood vessels. Using the most current form of technology called flow cytometry, he is trying to identify how the cells work and how they might ultimately be used to repair damaged blood vessels in diabetic patients or construct new vessels.
Sustained high blood sugar in people with diabetes damages the vascular system and often results in heart attack, stroke or amputation of limbs. While scientists do not fully understand the reasons these complications frequently occur in diabetics, a recently discovered type of adult stem cell seems to be incapacitated in these patients. Under normal conditions, these cells, called endothelial cell progenitors, help repair blood vessels or even form new ones.
"We previously discovered a new type of vascular progenitor," says Dr. Simper. "Our pilot data seem to confirm the notion that decreased number or function of vascular progenitor cells is a factor in compromising new vessel formation."
Adult stem cells renew themselves continuously in some organs of the body, providing a source of new cells for those organs. However, they are found in relatively minute quantities in the samples of blood Dr. Simper collects. Therefore, he must carefully nurture the cells in each sample to produce the progenitor cells.
Once he has enough of the progenitor cells, Dr. Simper uses flow cytometry technology to examine the characteristics of each one, and count and sort them. He is analyzing the progenitor cells' surface molecules, which are used to attach to other cells and communicate with each other in the process of forming new vessels.
Dr. Simper and other researchers at the Carl T. Hayden VA Medical Center are using a bench-top flow cytometry system made by Beckman Coulter Inc. that represents the latest version of this technology.
How Flow Cytometry Works Fluorescent dyes are joined, or conjugated, to antibodies, which recognize specific molecules on the surface of cells. A beam of laser light is aimed at the cells, carrying these antibodies, as they flow through the equipment suspended in fluid. The laser excites the cells into emitting and scattering light, which is picked up, amplified and analyzed for fluctuations in brightness. Researchers can extrapolate various types of information about the physical and chemical structure of each cell, based on the individual surface markers of the cell, as well as distinguish and sort separate subpopulations of cells and count their relative percentages. While flow cytometry takes measurements on one cell at a time, it can process thousands of cells in a few seconds.
More About Diabetes
Diabetes mellitus is a group of chronic diseases characterized by high levels of blood glucose, which occur when the body does not properly produce or use insulin, a hormone that converts carbohydrates into energy that can be used by the body.
Approximately 240,000 or more Arizona adults have diabetes, and it is a leading cause of death in the state, as well as the nation. At least 4 million hospitalizations and more than 26 million outpatient visits annually in the U.S. are associated with diabetes.
Type 1 diabetes occurs when the cells that produce insulin are destroyed. It usually begins in childhood or adolescence, and has been called juvenile-onset diabetes.
Dr. Simper's research is being funded by the Juvenile Diabetes Research Foundation.
# # #
Media Note:
This week is National VA Research Week, where VA is celebrating national research accomplishments. Some VA research accomplishments include discovering the cure for tuberculosis, creating the imaging for CAT scan technology and creating and implanting the first cardiac pacemaker.
The VA Medical Center is recruiting adults with or without diabetes to donate blood samples for this study.
Interviews are available with Dr. Simper and a patient.
# # #
Plug-In Notice:
Some documents on this web page require a separate plug-in application in order to view and print. The icon(s) listed below when placed next to a link in a web page indicates a plug-in is required and what type of plug-in is needed. Clicking the icons or links listed below will take you to a page from which you can download and install all plug-ins.
Word Document Format