Profiling Amino Acids to evaluate vascular function.

Profiling Amino Acids to evaluate vascular function.

As far as Amino Acid profiling, there are limited ways to evaluate vascular function despite this system major impact in the leading causes of death and disability, namely heart attack and stroke. Arginine is involved in many human biochemical functions including ammonia detoxification, hormone secretion, and immune modulation. In vascular function, Arginine is a key player in Nitric Oxide (NO) function, which is a soluble gas modulating arterial system. Arginine’s effect via NO has implications for angina pectoris, congestive heart failure, hypertension, coronary artery disease, preeclampsia, intermittent claudication, and erectile dysfunction. (5).

Arginine can be derived from diet, however mostly the body produces the 80-120 umol/L concentrations endogenously from the amino acid citrulline. Citrulline is involved in the Krebs Cycle and is a by product of glutamine metabolism. Citrulline is taken up in kidney where it is converted in Arginine.(5) Arginine and oxygen combine to form Nitric Oxide and Citrulline, and the rate of production governed by Nitrous Oxide Synthetase found in endothelium, neural tissue, macrophages and neutrophils (3). Of note, the specific inducers of NOS in the immune cells includes endotoxins (or lipopolysaccharides) (3, 4). The action of NO is mediated by the free radical oxidant properties of the gas, and also by its activation of guanylate cyclase leading to relaxation of smooth muscle in blood vessel walls (3,4). Pharmaceutically, we see the results of NO action with nitroglycerin effect during myocardial infarct (3).

Arginine is also the precursor for the synthesis of proteins, urea, creatine, and agmatine (5). As the precursor of NO, arginine is involved in many physiological effects of the cardiovascular system, and is critical for maintenance of blood pressure, myocardial function, inflammatory response, and oxidative processes (5). Due to the various processes it is involved in, Arginime has been called one of the most versatile amino acids (2). There are clinical applications described that include HIV/AIDS, cardiovascular conditions, preeclampsia, growth hormone and athletic performance, burns and critical care, cancer, GI and GU conditions, perioperative nutrition, and preterm labor.(5). Safety studies have shown that this amino acid is safe in typically recommended doses of 1-15 g per day.

Sources: 

(1)  Clinical Guidelines for Determination of Preferred Specimen Choice by Bradley Bongiovanni, ND and Judy Feinerman, MS, RD Townsend Letter for Doctors and Patients: the Examiner of Medical Alternatives December 2003 Issue # 245, 38-42.)

(2)   Morris, S.M., 2007. Arginine Metabolism: Boundaries of Our Knowledge. The Journal of Nutrition 137, 1602S-1609S. https://doi.org/10.1093/jn/137.6.1602S

(3)  Biochemistry

(4)   McCann, S.M., Licinio, J., Wong, M.L., Yu, W.H., Karanth, S., Rettorri, V., 1998. The nitric oxide hypothesis of aging. Exp. Gerontol. 33, 813–826.

(5)  Arginine: Clinical Potential of a Semi-Essential Amino Acid. Alternative Medicine Review Volume 7, Number 6 ◆ 2002