RESUMO
We evaluated whether anserine, a methylated analog of the dipeptide carnosine, is present in the cardiac and skeletal muscles of humans and whether the CARNMT1 gene, which encodes the anserine synthesizing enzyme carnosine-N-methyltransferase, is expressed in human skeletal muscle. We found that anserine is present at low concentrations (low micromolar range) in both cardiac and skeletal muscles, and that anserine content in skeletal muscle is ~15 times higher than in cardiac muscle (cardiac muscle: 10.1 ± 13.4 µmol·kg-1 of dry muscle, n = 12; skeletal muscle: 158.1 ± 68.5 µmol·kg-1 of dry muscle, n = 11, p < 0.0001). Anserine content in the heart was highly variable between individuals, ranging from 1.4 to 45.4 µmol·kg-1 of dry muscle, but anserine content was not associated with sex, age, or body mass. We also showed that CARNMT1 gene is poorly expressed in skeletal muscle (n = 10). This is the first study to demonstrate that anserine is present in the ventricle of the human heart. The presence of anserine in human heart and the confirmation of its expression in human skeletal muscle open new avenues of investigation on the specific and differential physiological functions of histidine dipeptides in striated muscles.
Assuntos
Anserina , Carnosina , Humanos , Anserina/análise , Anserina/metabolismo , Carnosina/análise , Carnosina/metabolismo , Músculo Esquelético/metabolismo , Dipeptídeos/metabolismo , Miocárdio/metabolismoRESUMO
Intensive systems of raising chickens in barns prevail worldwide for financial reasons. In contrast, free-range chickens are raised in better welfare conditions, and preferred by consumers due to their distinctive taste/flavor, having higher market prices. Thus, free-range chickens have been the target of frauds. In this study, 1H NMR metabolic profiles of breasts of free-range and barn-raised broilers (108 individuals) were compared by two discriminant models, based on t-test ranking and partial least squares (PLS-DA). Both models provided 100 % of correct classification in both training and test sets, being the univariate model based on t-test screening simpler and more robust. Among other differences, barn-raised broilers presented lower carnosine and anserine concentrations, and higher free amino acids contents. Univariate discrimination was based on the ratio of two NMR signals assigned to ß-alanine and carnosine + anserine, respectively. As an additional advantage, this profiling method could be adapted to other measurement platforms.