An analysis of urine and serum amino acids in critically ill patients upon admission by means of targeted LC–MS/MS: a preliminary study

Sepsis, defined as a dysregulated host response to infection, causes the interruption of homeostasis resulting in metabolic changes. An examination of patient metabolites, such as amino acids, during the early stage of sepsis may facilitate diagnosing and assessing the severity of the sepsis. The aim of this study was to compare patterns of urine and serum amino acids relative to sepsis, septic shock and survival. Urine and serum samples were obtained from healthy volunteers (n = 15) once or patients (n = 15) within 24 h of a diagnosis of sepsis or septic shock. Concentrations of 25 amino acids were measured in urine and serum samples with liquid chromatography-electrospray mass spectrometry. On admission in the whole cohort, AAA, ABA, mHis, APA, Gly-Pro and tPro concentrations were significantly lower in the serum than in the urine and Arg, Gly, His, hPro, Leu, Ile, Lys, Orn, Phe, Sarc, Thr, Tyr, Asn and Gln were significantly higher in the serum than in the urine. The urine Gly-Pro concentration was significantly higher in septic shock than in sepsis. The serum Cit concentration was significantly lower in septic shock than in sepsis. The urine ABA, mHis and Gly-Pro, and serum Arg, hPro and Orn concentrations were over two-fold higher in the septic group compared to the control group. Urine and serum amino acids measured in septic patients on admission to the ICU may shed light on a patient’s metabolic condition during sepsis or septic shock.

Serum Amino Acids Patterns and 4-Year Sarcopenia Risk in Community-Dwelling Chinese Older Adults

<b><i>Introduction:</i></b> Dietary protein intake and serum amino acids (AAs) are factors controlling the rate of muscle protein synthesis and catabolism. This study examined the association between serum AAs patterns and incident sarcopenia in community-dwelling older adults. <b><i>Methods:</i></b> Chinese older adults in Hong Kong aged ≥65 years attended a health check at baseline and 4-year follow-up. At baseline, fasting blood was collected to measure 17 serum AAs. Serum AAs patterns were identified using principal component analysis. Dietary protein intake was assessed using a validated food frequency questionnaire. A composite score was computed by summing the principal component score and sex-standardized protein intake. Six composite scores representing each AAs pattern were available for each participant. Sarcopenia was defined using the updated version of the Asian Working Group for Sarcopenia. Crude and adjusted multiple logistic regressions were performed to examine the associations between each of the 6 composite scores and sarcopenia over 4 years. Results are presented as odds ratio (OR) and 95% confidence interval (CI). To address multiple testing, a Bonferroni correction was applied using a corrected significance level of <i>p</i> &#x3c; 0.008 (α 0.05/6 patterns). <b><i>Results:</i></b> Data of 2,610 participants (mean age 71.6 years, 45.4% men) were available. In men, serum AAs patterns characterized by high branched-chain AAs (BCAAs) (OR 0.77, 95% CI 0.69–0.87, <i>p</i> &#x3c; 0.001) and tyrosine, tryptophan, and phenylalanine (OR 0.79, 95% CI 0.71–0.89, <i>p</i> &#x3c; 0.001) were significantly associated with a lower risk of sarcopenia over 4-year follow-up. After adjusting for confounders, the associations were no longer significant. In women, serum AAs patterns characterized by glutamine, glutamic acid, and methionine (OR 1.28, 95% CI 1.11–1.47, <i>p</i> = 0.001) and arginine, taurine, and serine (OR 1.20, 95% CI 1.06–1.35, <i>p</i> = 0.003) were associated with a higher risk of sarcopenia. After adjusting for confounders, serum AAs pattern characterized by high BCAAs (adjusted OR 1.52, 95% CI 1.25–1.86, <i>p</i> &#x3c; 0.001) and arginine, taurine, and serine (adjusted OR 1.30, 95% CI 1.09–1.56, <i>p</i> = 0.004) were significantly associated with a higher risk of sarcopenia. No association between other AAs patterns with incident sarcopenia was found. <b><i>Conclusions:</i></b> In community-dwelling Chinese older adults, serum AAs patterns characterized by high BCAAs and nonessential AAs (arginine, taurine, and serine) were associated with a higher risk of sarcopenia in women. Findings may allow identifying new targets for interventions.

Prospective study on the association between serum amino acid profiles and depressive symptoms among the Japanese working population

Objective Accumulating evidence suggests that amino acids, particularly tryptophan and glutamate, play an important role in the pathology of depression, but prospective epidemiologic data on this issue is scarce. We examined the association between circulating amino acids and the risk of depressive symptoms in a Japanese working population. Methods Participants were 841 workers who were free from depressive symptoms and provided blood at baseline and completed 3-yr follow-up survey. 30 varieties of amino acid concentrations in serum were measured using liquid chromatography/mass spectrometry. Depressive symptoms were defined using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to calculate the odds ratios of depressive symptoms according to serum amino acids with adjustment for lifestyle factors. Results A total of 151 (18.0%) workers were newly identified as having depressive symptoms at the follow-up. Baseline tryptophan and glutamate concentrations in serum were not appreciably associated with the risk of depressive symptoms. Risk of depressive symptoms tended to increase with increasing arginine concentrations; the multivariable-adjusted odds ratio for the highest versus lowest tertile of serum arginine was 1.65 (95% confidence interval: 0.96–2.83; P for trend = 0.07). No clear association was found for other amino acids. Conclusions Results of the present study do not support a significant role of circulating amino acids in the development of depressive symptoms among Japanese.