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Vascular calcification location, formation and biological activity
Published on February 4, 2014 31 min
A selection of talks on Cardiovascular & Metabolic
Anticoagulation for venous thromboembolism
- Dr. Allyson Pishko
- University of Pennsylvania, USA
Pathophysiology and treatment of congestive heart failure in dogs and cats
- Prof. Jessica Ward
- Iowa State University, USA
Genome scans for hypertension
- Prof. Patricia Munroe
- Queen Mary's School of Medicine and Dentistry, UK
My name is Diane Proudfoot. I work at the Babraham Institute in Cambridge. And I'm going to talk to you about vascular calcification. I'm going to talk about where it's located, how vascular calcification is formed and how it's regulated. And I'm also going to talk about the biological activity of vascular calcification.
I would like to start by describing the normal structure of a blood vessel wall. And this is a cartoon image of a cross section through a blood vessel wall. You can see that the blood vessel is made up of three distinct layers. These are called the intima, the media, and the adventitia. The layer that's exposed to the blood is called the intima. And this is covered on the lumenal side by a single sheet of endothelial cells. The intima provides a smooth, non-thrombogenic surface and acts as a permeability barrier to cells and macromolecules. Beneath the intima is a sheet of elastic fibers. And this is called the internal elastic lamina. The layer below is called the media. And this contains vascular smooth muscle cells and matrix proteins. The main function of smooth muscle cells is to contract and to dilate to achieve normal vascular tone. The outermost layer is the adventitia. And this is separated from the media by the external elastic lamina. The adventitia layer contains fibroblasts, small blood vessels, and it also contains nerve innervation to the blood vessel.
In early atherosclerosis, some changes occur in the intima layer of the blood vessel wall. Endothelial cells become activated or damaged. And this causes the attraction of leukocytes from the blood to roll along the endothelium and to enter into the intima layer. When inflammatory cells, such as macrophages, enter into the intima, they secrete factors, proteins, and chemo attractants, which attracts smooth muscle cells from the media layer to change their phenotype from contractile to a secretory phenotype or a repair phenotype in the intima of the blood vessel wall. Another change that happens is that lipid proteins from the blood accumulate in the intima layer. And also, at this very early stage, you can start to detect some small diffuse particles of calcium phosphate crystals, which is an early sign of calcification.