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

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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 2nd and 3rd 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- + ortho-tyrosine)/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.

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Time course of myocardial release of D stereoisomer of p-, m- and o-Tyr in the cardiac effluent at baseline and at various time points during reperfusion after 30-min ischemia. Hearts were perfused with D-Phe. Data are mean + S.E.; n =8; *p <0.05 vs. pre-ischemic value. Fig. reproduced from Biondi et al. Cardiovasc. Res. 2006, 15;71(2):322-330 [50] with permission of Oxford University Press.
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Figure 5: Time course of myocardial release of D stereoisomer of p-, m- and o-Tyr in the cardiac effluent at baseline and at various time points during reperfusion after 30-min ischemia. Hearts were perfused with D-Phe. Data are mean + S.E.; n =8; *p <0.05 vs. pre-ischemic value. Fig. reproduced from Biondi et al. Cardiovasc. Res. 2006, 15;71(2):322-330 [50] with permission of Oxford University Press.


Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review
Time course of myocardial release of D stereoisomer of p-, m- and o-Tyr in the cardiac effluent at baseline and at various time points during reperfusion after 30-min ischemia. Hearts were perfused with D-Phe. Data are mean + S.E.; n =8; *p <0.05 vs. pre-ischemic value. Fig. reproduced from Biondi et al. Cardiovasc. Res. 2006, 15;71(2):322-330 [50] with permission of Oxford University Press.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4997921&req=5

Figure 5: Time course of myocardial release of D stereoisomer of p-, m- and o-Tyr in the cardiac effluent at baseline and at various time points during reperfusion after 30-min ischemia. Hearts were perfused with D-Phe. Data are mean + S.E.; n =8; *p <0.05 vs. pre-ischemic value. Fig. reproduced from Biondi et al. Cardiovasc. Res. 2006, 15;71(2):322-330 [50] with permission of Oxford University Press.

View Article: PubMed Central - PubMed

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 2nd and 3rd days (p&lt;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&lt;0.01 for both). Using linear regression model, meta-tyrosine excretion, urinary meta-tyrosine/para-tyrosine, urinary ortho-tyrosine/para-tyrosine and urinary (meta- + ortho-tyrosine)/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.

No MeSH data available.


Related in: MedlinePlus