Endothelial cells compose the inner lining of blood vessels. Blood vessels function as a conduit for the delivery of oxygen, nutrients, hormones, proteins, immune factors and the removal of waste. Dysfunction of endothelial cells and the buildup of cholesterol causes problems for multiple organ systems. The prevention, diagnosis and treatment of disease should be undertaken with the consultation of a healthcare professional.
Atherosclerosis
Endothelial dysfunction and high total cholesterol and LDL cholesterol contribute the formation of atherosclerosis. Atherosclerosis is a buildup of plaque in the blood vessels. This is dangerous because it restricts blood flow to the organs. If the blood flow is cut off in the heart, this causes a heart attack, if it occurs in the brain it causes a stroke. Even if blood vessel to an area of an organ is not completely occluded, a decreased blood supply can damage the organs.
Pathogenesis
The endothelial cells lining the blood vessels are susceptible to damage by oxidative stress. This occurs when highly reactive chemicals called free radicals damage the cells. In addition, free radicals damage LDL cholesterol which binds to the endothelial cells. This forms a plaque that activates immune cells that invade the plaque. Immune cells release factors that cause the muscular layer of the artery to grow, which further narrows the blood vessel.
Risk Factors
There are defined risk factors for atherosclerosis and heart and blood vessel disease. These are divided into risk factors that cannot be changed and those that can. Risk factors that cannot be changed include advanced age, sex, with males having a higher risk until women undergo menopause, a family history of atherosclerosis and heart disease, or a genetic disorder. Modifiable risk factors include smoking, sedentary lifestyle, diabetes, high blood pressure, high total and LDL cholesterol, high blood levels of a protein called C-RP, the chemical homocysteine and Lp-a. In addition stress, depression and a few other risk factors can contribute.
Diagnosis
The diagnosis of endothelial dysfunction can be made by doing an ultrasound on an artery in the arm called the brachial artery. Tests of the heart, such as a stress test in which imaging or an ECG are performed when the heart is working harder than usual, either on a treadmill or medically induced, can reveal heart disease. Atheroscerotic lesions can also be seen on angiography. In this technique, a physician injects dye into an artery and then takes an X-ray to look for narrowing. Blood levels of LDL, C-RP, homocysteine and others can be tested for.
Prevention
Prevention mostly entails addressing the modifiable risk factors listed above. Tobacco use should be stopped. Exercise is encouraged. It may be necessary to medically manage some risk factors, such as giving medicines for high cholesterol.
Treatment
Treatment is divided into lifestyle management, medications and surgical interventions. Lifestyle management includes changes such as tobacco cessation, proper diet and exercise. Medications include those that decrease demand on the heart, lower cholesterol and blood pressure. Surgical interventions can sometimes remove plaques, open arteries, or move a blood vessel to another area of the body to bypass an obstructed artery.
References
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar et al.; 8th Ed 2009
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci et al.; 17th Ed 2008
- "Circulation"; "Role of endothelial dysfunction in atherosclerosis."; Davignon J, Ganz P; 2004
