Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review

Title:Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review

Volume: 23 Issue: 7

Author(s): Gergő A. Molnár, Szilárd Kun, Eszter Sélley, Melinda Kertész, Lívia Szélig, Csaba Csontos, Katalin Böddi, Lajos Bogár, Attila Miseta and István Wittmann

Affiliation:

Keywords: Meta-tyrosine, ortho-tyrosine, para-tyrosine, sepsis, inflammation, oxidative stress, hormone resistance, carbohydrate metabolism.

Abstract: Oxidative stress plays a major role in the pathogenesis of a variety of acute and chronic diseases. Measurement of the oxidative stress-related end products may be performed, e.g. that of structural isomers of the physiological para-tyrosine, namely meta- and ortho-tyrosine, that are oxidized derivatives of phenylalanine. Recent data suggest that in sepsis, serum level of meta-tyrosine increases, which peaks on the 2^nd and 3^rd days (p<0.05 vs. controls), and the kinetics follows the intensity of the systemic inflammation correlating with serum procalcitonin levels. In a similar study subset, urinary meta-tyrosine excretion correlated with both need of daily insulin dose and the insulin-glucose product in non-diabetic septic cases (p<0.01 for both). Using linear regression model, meta-tyrosine excretion, urinary meta-tyrosine/para-tyrosine, urinary ortho-tyrosine/para-tyrosine and urinary (meta- + orthotyrosine)/ para-tyrosine proved to be markers of carbohydrate homeostasis.

In a chronic rodent model, we tried to compensate the abnormal tyrosine isomers using para-tyrosine, the physiological amino acid. Rats were fed a standard high cholesterol-diet, and were given para-tyrosine or vehicle orally. High-cholesterol feeding lead to a significant increase in aortic wall meta-tyrosine content and a decreased vasorelaxation of the aorta to insulin and the glucagon-like peptide-1 analogue, liraglutide, that both could be prevented by administration of para-tyrosine.

Concluding, these data suggest that meta- and ortho-tyrosine are potential markers of oxidative stress in acute diseases related to oxidative stress, and may also interfere with insulin action in septic humans. Competition of meta- and ortho-tyrosine by supplementation of para-tyrosine may exert a protective role in oxidative stress-related diseases.

Cite this article as:

Molnár A. Gergő, Kun Szilárd, Sélley Eszter, Kertész Melinda, Szélig Lívia, Csontos Csaba, Böddi Katalin, Bogár Lajos, Miseta Attila and Wittmann István, Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review, Current Medicinal Chemistry 2016; 23 (7) . https://dx.doi.org/10.2174/0929867323666160119094516