Endothelial dysfunction is the start of the process of damage to the blood vessels of the body resulting in arteriosclerosis. Risk factors that increase endothelial dysfunction include hypertension, diabetes, abnormal blood fats and smoking.

Endothelial dysfunction is first manifest by poor relaxation of the inner endothelial lining of blood vessels. This failure has been found to be due to the poor conversion of l-arginine amino acid to nitric oxide because of insufficiency of endothelial nitric oxide synthetase enzyme (eNOS) or of tetrahydrobiopterin (a cofactor for eNOS.) L-arginine plays a protective role over the endothelium.

Endothelial progenitor cells (EPC’s) are the building blocks for the development of endothelial cells. Endothelial cells are cells that line the cavities of the body, including the blood vessels. Failure of the EPC’s to progress normally to be endothelial cells results in poor healing of any damage to the inner lining of blood vessels.

Nitric oxide (NO) in blood vessel walls has both anti-inflammatory and anti-thrombotic properties and may prevent atherosclerosis.

When tetrahydrobiopterin (BH4) is in low supply, eNOS produces superoxide instead of NO, which causes oxidative damage to the cells. BH4 deficiency speeds up the development of arteriosclerosis and giving BH4 can treat arteriosclerosis.

Weight reduction with exercise is effective in reducing endothelial dysfunction in overweight adults and obese children.

High-density lipoprotein (HDL) stimulates eNOS activity. Anything that increases HDL will improve endothelial function and improve circulation to the heart.

CONCLUSION: Endothelial dysfunction is an important part of the development of arteriosclerosis. Various agents are listed which improve endothelial function including BH4 and l-arginine amino acid.

NOTE: Read more about the multiple functions of nitric oxide and arginine.

PMID: 16234629.

Summary #083.