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.