Endothelial Dysfunction Associated Diseases and Disorders
Endothelial dysfunction is a pathological state of the inner lining of blood vessels, characterized by reduced bioavailability of nitric oxide (NO) and an imbalance between vasodilating and vasoconstricting substances. It is an early event in the development of atherosclerosis, hypertension, and other cardiovascular diseases. Two important biomarkers for endothelial dysfunction are asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA).
1. Overview of ADMA and SDMA
• ADMA (Asymmetric Dimethylarginine): An endogenous inhibitor of nitric oxide synthase (NOS), reducing NO production and impairing vasodilation.
• SDMA (Symmetric Dimethylarginine): Does not directly inhibit NOS but interferes with L-arginine transport into cells, indirectly affecting NO synthesis.
2. Roles in Physiology and Pathophysiology
• In healthy physiology, dimethylarginines are produced during protein turnover when methylated arginine residues are degraded.
• Elevated ADMA levels inhibit NOS, leading to endothelial dysfunction and contributing to hypertension, atherosclerosis, and chronic kidney disease.
• Elevated SDMA levels are strongly correlated with reduced renal function and cardiovascular risk.
3. Limitations
• ADMA and SDMA levels can be influenced by renal function, protein intake, and certain medications.
• Interpretation requires correlation with other endothelial function tests (e.g., flow-mediated dilation).
4. Applications
• Risk stratification in cardiovascular disease.
• Monitoring endothelial function in clinical trials.
• Early detection of vascular damage in chronic kidney disease.