Background Aromatic and branched-chain amino acids and alanine have correlated positively, and valine, histidine and glutamine negatively with increasing levels of glucose. Those changes were at leat in part explained by insulin resistance. Insulin resistance is increased in inflammatory conditions like RA.
Objectives To investigate amino acid metabolism (isoleucine, tyrosine, alanine, phenylalanine, leucine, valine, histidine, glutamine) among patients with newly diagnosed rheumatoid arthritis (RA) in a population based cohort.
Methods For quantification of amino acids serum nuclear magnetic resonance platform operating at 500 MHz was used in native serum samples from patients with RA participating in Northern Savo 2010 Study. Correlations between age- and BMI-adjusted amino acid concentrations and patient reported general health (GH, VAS) were evaluated. The 95% confidence intervals for the correlations were obtained by bias-corrected bootstrapping (5,000 replications).
Results Serum samples from 63 patients, 34 females and 29 males, with RA satisfying the ACR/Eular 2010 classification criteria were studied. The mean age (SD) of patients was 59.1 (12.0) years and the BMI (SD) 27.3 (5.4) kg/m2. 69.8% had anti-CCP antibodies. The mean DAS28 was 4.4 (1.3) and GH 52.7 (25.7). Correlations between age- and BMI-djusted amino acid concentrations and patient reported GH are shown in table.
Phenylalanine, histidine and glutamine concentrations also correlated with CRP r=0.71, p<0.001, r=-0.50, p<0.001, and r=-0.33, p=0.013, respectively.
Conclusions In untreated RA phenylalanine correlated positively with patient reported GH (higher disease burden) and CRP, whereas histidine and glutamine correlated negatively with them. In diabetes phenylalanine increased and histidine and glutamine decreased along with disturbances in glucose metabolism and in inflammation they may reflect inflammation associated insulin resistance.
Svenson KLG et al. Metabolism 1987;36:940–3.
Soininen P et al. Analyst 2009;134:1781-5.
Stančáková A et al. Diabetes 2012;61:1895-902.
Disclosure of Interest None declared