Endothelial cells serve as the interface between the blood and the arteries, controlling arterial tone and helping to prevent clots that lead to strokes and heart attacks, says Ibhar Al Mheid, MD, a postdoctoral cardiology researcher at Emory.
He is scheduled to present his results in a poster session Monday, Nov. 10 at the American Heart Association Scientific Sessions in New Orleans.
"One of the important ways the lining of our blood vessels is maintained is by progenitor cells that come from the bone marrow," Al Mheid says. "These are essentially stem cells that help replace endothelial cells at sites of injury and build new vessels at sites deprived of adequate blood supply. The aim of our research was to look at the circadian pattern of both endothelial function -- the ability of blood vessels to relax -- and the abundance of the progenitor cells."
Working with Arshed Quyyumi, MD, professor of medicine and director of the Emory Cardiovascular Research Group, and colleagues, Al Mheid examined a dozen healthy middle-aged subjects every four hours for 24 hours. They drew blood while the subjects were asleep at 4 a.m. Blood vessel relaxation is assessed by cuff occlusion, a standard technique in measuring blood pressure – and was not measured at 4 a.m.
The researchers measured the ability of subjects' blood vessels to relax, the abundance of endothelial progenitor cells (EPCs) and their ability to grow in culture. Both the ability of blood vessels to relax and EPCs' ability to grow peaked (roughly 40 percent more than the middle of the day) at midnight, while cell numbers peaked at 8 p.m.
"The lining of our vessels appears to function better at night than in the day. Endothelial function is particularly depressed in the early morning hours," Al Mheid says.
He hypothesizes that an innate circadian timer in the brain, which other scientists have shown to be influenced by light and dark and daily activities, drives the cyclical variations in EPCs and endothelial function.
About Emory Heart & Vascular Center
Emory Heart & Vascular Center doctors are committed to providing clinically excellent cardiovascular patient care, pioneering innovative clinical research and training the best heart specialists in the world. A component of Emory Healthcare, the Center is consistently recognized by U.S. News & World Report as one of the top heart centers in the country.
Jennifer Johnson | EurekAlert!
Enabling technology in cell-based therapies: Scale-up, scale-out or program in-place
23.07.2018 | SLAS (Society for Laboratory Automation and Screening)
FAU researchers identify Parkinson's disease as a possible autoimmune disease
23.07.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
23.07.2018 | Materials Sciences
23.07.2018 | Information Technology
23.07.2018 | Health and Medicine