In a study published Nov. 9 in the Journal of Biological Chemistry, the researchers report that blood vessels are less like to clog in people with diabetes who get adequate vitamin D. But in patients with insufficient vitamin D, immune cells bind to blood vessels near the heart, then trap cholesterol to block those blood vessels.
Low levels of vitamin D in people with diabetes appear to encourage cholesterol to build up in arteries, eventually blocking the flow of blood. In mice, immune cells adhering to the wall of a major blood vessel near the heart are loaded with cholesterol (shown in red).
“About 26 million Americans now have type 2 diabetes,” says principal investigator Carlos Bernal-Mizrachi, MD. “And as obesity rates rise, we expect even more people will develop diabetes. Those patients are more likely to experience heart problems due to an increase in vascular inflammation, so we have been investigating why this occurs.”
In earlier research, Bernal-Mizrachi, an assistant professor of medicine and of cell biology and physiology, and his colleagues found that vitamin D appears to play a key role in heart disease. This new study takes their work a step further, suggesting that when vitamin D levels are low, a particular class of white blood cell is more likely to adhere to cells in the walls of blood vessels.
Vitamin D conspires with immune cells called macrophages either to keep arteries clear or to clog them. The macrophages begin their existence as white blood cells called monocytes that circulate in the bloodstream. But when monocytes encounter inflammation, they are transformed into macrophages, which no longer circulate.
In the new study, researchers looked at vitamin D levels in 43 people with type 2 diabetes and in 25 others who were similar in age, sex and body weight but didn’t have diabetes.They found that in diabetes patients with low vitamin D — less than 30 nanograms per milliliter of blood — the macrophage cells were more likely to adhere to the walls of blood vessels, which triggers cells to get loaded with cholesterol, eventually causing the vessels to stiffen and block blood flow.
“We took everything into account,” says first author Amy E. Riek, MD, instructor in medicine. “We looked at blood pressure, cholesterol, diabetes control, body weight and race. But only vitamin D levels correlated to whether these cells stuck to the blood vessel wall.”
Riek and Bernal-Mizrachi say what’s not yet clear is whether giving vitamin D to people with diabetes will reverse their risk of developing clogged arteries, a condition called atherosclerosis. They now are treating mice with vitamin D to see whether it can prevent monocytes from adhering to the walls of blood vessels near the heart, and they also are conducting two clinical trials in patients.
In one of those studies, the researchers are giving vitamin D to people with diabetes and hypertension to see whether the treatment may lower blood pressure. In the second study, African Americans with type 2 diabetes are getting vitamin D along with their other daily medications, and the research team is evaluating whether vitamin D supplements can slow or reverse the progression of heart disease.
Sometime in the next several months, the scientists hope to determine whether vitamin D treatment can reverse some of the risk factors associated with cardiovascular disease.
“In the future, we hope to generate medications, potentially even vitamin D itself, that help prevent the deposit of cholesterol in the blood vessels,” Bernal-Mizrachi explains. “Previous studies have linked vitamin D deficiency in these patients to increases in cardiovascular disease and in mortality. Other work has suggested that vitamin D may improve insulin release from the pancreas and insulin sensitivity. Our ultimate goal is to intervene in people with diabetes and to see whether vitamin D might decrease inflammation, reduce blood pressure and lessen the likelihood that they will develop atherosclerosis or other vascular complications.”
For more information on the current clinical studies involving vitamin D in people with diabetes, call study coordinator Robin Bruchas at (314) 362-0934.Riek AE, Sprague JE, Timpson A, de las Fuentes L, Bernal-Mizrachi L, Schechtman KB, Bernal-Mizrachi C. Vitamin D suppression of endoplasmic reticulum stress promotes an anti-atherogenic monocyte/macrophage phenotype in type 2 diabetic patients. Journal of Biological Chemistry vol. 287 (46), pp. 38482-38494. Nov. 9, 2012
Funding for this research comes from the National Heart, Lung and Blood Institute (NHLBI), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Center for Research Resources (NCRR), National Center for Advancing Translational Sciences (NCATS), and NIH Roadmap for Medical Research of the National Institutes of Health (NIH). Support also comes from the American Diabetes Association, the Endocrine Society, the Endocrine Fellows Foundation and the Ruth L. Kirchstein National Research Service Award 2. NIH grant numbers are RO1 HO094818-0, P30DK079333, T32 HD043010, and UL1TRR000448/Sub-Award KL2TR000450.
Washington University School of Medicine’s 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked sixth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.
Jim Dryden | EurekAlert!
Further reports about: > Biological Chemistry > CHEMISTRY > Diabetes > Endocrine > Vitamin B > blood cell > blood flow > blood pressure > blood vessel > cardiovascular disease > health services > heart disease > immune cell > risk factor > type 2 diabetes > vascular disease > vitamin D levels > white blood cell
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Machine Engineering
17.01.2017 | Physics and Astronomy