Blood serum amino acid pool violation of in patients with liver cirrhosis

Objective. To investigate serum amino acid pool changes in patients with liver cirrhosis. Materials and methods. 95 patients with liver cirrhosis were participated in the study. In the 1st group (class A disease severity according to Child- Pugh score) there were 18 (18.95%) patients, in the 2nd group (class B) - 25 (26.3%), in the 3rd groups (class C) - 52 (54.7%) patients. The amount of free amino acids in blood serum was determined by reversed-phase high-performance liquid chromatography in isocratic elution mode with electrochemical detection. Results. Violations of free amino acid reserves were revealed in patients with cirrhosis of the liver with a predominant accumulation of aromatic amino acids: phenylalanine - (162.45 ± 14.12) nmol/ml, tyrosine - (99.05 ± 10.07) nmol/ml, tryptophan - (76.10 ± 12.40) nmol/ml, as well as an increase in the content of proline, lysine, cysteine (p <0.05) . In parallel, the decreasing of free serum amino acids with branched side chain levels were observed: valine - up (150.10 ± 8.92) nmol/ml leucine - up (75.14 ± 5.12) nmol/ml (p < 0.05) and isoleucine - up to (80.40 ± 8.01) nmol/ml. Conclusions. The correlation between the second degree of thick guts dysbiosis and increased levels of tryptophan was determined (r = 0.77; p <0.01). III degree thick dysbiosis was correlated with increasing levels of phenylalanine (r = 0.71; p <0.01). In patients of 2nd group the correlations between levels of tryptophan and II degree of intestinal dysbiosis (r = 0.58; p <0.01) and the levels of tyrosine in phenylalanine in III stage intestinal dysbiosis were detected.

Hypoxic Adaptation of Mitochondrial Metabolism in Rat Cerebellum Decreases in Pregnancy

Function of brain amino acids as neurotransmitters or their precursors implies changes in the amino acid levels and/or metabolism in response to physiological and environmental challenges. Modelling such challenges by pregnancy and/or hypoxia, we characterize the amino acid pool in the rat cerebellum, quantifying the levels and correlations of 15 amino acids and activity of 2-oxoglutarate dehydrogenase complex (OGDHC). The parameters are systemic indicators of metabolism because OGDHC limits the flux through mitochondrial TCA cycle, where amino acids are degraded and their precursors synthesized. Compared to non-pregnant state, pregnancy increases the cerebellar content of glutamate and tryptophan, decreasing interdependence between the quantified components of amino acid metabolism. In response to hypoxia, the dependence of cerebellar amino acid pool on OGDHC and the average levels of arginine, glutamate, lysine, methionine, serine, phenylalanine, and tryptophan increase in non-pregnant rats only. This is accompanied by a higher hypoxic resistance of the non-pregnant vs. pregnant rats, pointing to adaptive significance of the hypoxia-induced changes in the cerebellar amino acid metabolism. These adaptive mechanisms are not effective in the pregnancy-changed metabolic network. Thus, the cerebellar amino acid levels and OGDHC activity provide sensitive markers of the physiology-dependent organization of metabolic network and its stress adaptations.

Development of an UPLC mass spectrometry method for measurement of myofibrillar protein synthesis: application to analysis of murine muscles during cancer cachexia

Cachexia, characterized by skeletal muscle mass loss, is a major contributory factor to patient morbidity and mortality during cancer. However, there are no reports on the rate of myofibrillar protein synthesis (MPS) in skeletal muscles that vary in primary metabolic phenotype during cachexia, in large part because of the small-size muscles and regional differences in larger muscles in the mouse. Here, we describe a sensitive method for measurement of MPS and its application to analysis of MPS in specific muscles of mice with ( Apc Min/+) and without (C57BL/6) cancer cachexia. Mice were injected with a loading dose of deuterated phenylalanine (D5F), and myofibrillar proteins were extracted from skeletal muscles at 30 min. The relative concentrations of D5F and naturally occurring phenylalanine (F) in the myofibrillar proteins and the amino acid pool were quantified by ultra-performance liquid chromatograph (UPLC) mass spectrometry (MS). The rate of MPS was determined from D5F-to-F ratio in the protein fraction compared with the amino acid pool. The rate of MPS, measured in 2–5 mg of muscle protein, was reduced by up to 65% with cachexia in the soleus, plantaris, diaphragm, and oxidative and glycolytic regions of the gastrocnemius. The rate of MPS was significantly higher in the oxidative vs. glycolytic gastrocnemius muscle. A sufficiently sensitive UPLC MS method requiring a very small amount of muscle has been developed to measure the rate of MPS in various mouse muscles. This method should be useful for studies in other animal models for quantifying effects of cancer and anti-cancer therapies on protein synthesis in cachexia, and particularly for analysis of sequential muscle biopsies in a wide range of animal and human studies.