Intimal hyperplasia is the thickening of the
tunica intima
The tunica intima (Neo-Latin "inner coat"), or intima for short, is the innermost tunica (biology), tunica (layer) of an artery or vein. It is made up of one layer of endothelium, endothelial cells (and macrophages in areas of disturbed blood flo ...
of a blood vessel as a complication of a reconstruction procedure or
endarterectomy
Endarterectomy is a surgical procedure to remove the atheromatous ''plaque'' material, or blockage, in the lining of an artery constricted by the buildup of deposits. It is carried out by separating the plaque from the arterial wall.
It was firs ...
. Intimal hyperplasia is the universal response of a vessel to injury. It is a
restenosis
Restenosis is the recurrence of stenosis, a narrowing of a blood vessel, leading to restricted blood flow. Restenosis usually pertains to an artery or other large blood vessel that has become narrowed, received treatment to clear the blockage, and ...
and this is an important reason of late
bypass graft failure, particularly in vein and synthetic vascular grafts.
Cause
Intimal hyperplasia is due to a dysfunction of
endothelial cells
The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the res ...
which results in a reprogramming of the
vascular smooth muscle cells (VSMCs). As a result, VSMCs proliferate and change their
phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...
.
Possible treatment
A possible treatment to avoid this could be
hydrogen sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...
. Hydrogen sulfide () works as a vasculoprotective
gasotransmitter
Gasotransmitters is a class of neurotransmitters. The molecules are distinguished from other bioactive endogenous gaseous signaling molecules based on a need to meet distinct characterization criteria. Currently, only nitric oxide, carbon monoxid ...
in the human body but is also tested to reduced intimal hyperplasia. There are different kinds of donors: NaHS (the reference in scientific literature despite the fact it is too toxic to use it in human patients) and STS (already used in patient to treat
cyanide poisoning
Cyanide poisoning is poisoning that results from exposure to any of a number of forms of cyanide. Early symptoms include headache, dizziness, fast heart rate, shortness of breath, and vomiting. This phase may then be followed by seizures, slo ...
).
See also
*
Hyperplasia
Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of Tissue (biology), organic tissue that results from ...
*
Medical grafting
Grafting refers to a surgical procedure to move tissue from one site to another on the body, or from another creature, without bringing its own blood supply with it. Instead, a new blood supply grows in after it is placed. A similar techniqu ...
References
External links
''"Intimal hyperplasia, the obstacle in bypass grafts''"
Diseases of arteries, arterioles and capillaries
{{circulatory-disease-stub