Serum and synovial fluid histidine: a comparison in rheumatoid arthritis and osteoarthritis

Abstract

The serum and synovial fluid (SF) histidine, sulphydryl, and protein concentrations were compared in simultaneous samples from 84 patients with rheumatoid arthritis (RA) and a control group comprising 29 patients with osteoarthritis (OA). The SF levels of histidine were higher than the serum levels in the RA patients but significantly lower than corresponding results in patients with OA (P less than 0.001). The latter had levels of serum and SF histidine which were equivalent and within the normal range. Greater quantities of protein were found in the SF of the patients with RA compared with the OA group. The serum and SF sulphydryl concentrations expressed as mumol/g protein were low but in equilibrium in patients with RA. However the SF sulphydryl (mumol/g protein) was depressed relative to serum levels in patients with OA.

Serum branched-chain amino acid to histidine ratio: a novel metabolomic biomarker of knee osteoarthritis

“…However, the serum concentration of histidine itself is not associated with knee osteoarthritis in the current study. This is consistent with previous reports21 22 in which the concentration of histidine in both serum and synovial fluid were equivalent and within the normal range in knee osteoarthritis patients but significantly lower in rheumatoid arthritis patients. However, Lamers et al 6 suggested that osteoarthritis patients had a lower level of histidine and methylhistidine in urine.…”

Diagnostic properties of metabolic perturbations in rheumatoid arthritis

“…Previous findings have suggested that histidine catabolism is increased in patients with RA, although the reasons for this are unclear [33]. None of the direct products of histidine metabolism were detected in this study, but this should be the topic of a future study because of its apparent importance in RA and it might possibly lead to a better understanding of the pathophysiology of RA.…”

Detection and investigation of the molecular nature of low‐molecular‐mass copper ions in isolated rheumatoid knee‐joint synovial fluid

“…However, with mean normal and rheumatoid levels of 1.192× l0 -4 and 1.005× l0 -4 mol-dm -3 respectively, little Cu(II) binding capacity is lost. Moreover, rheumatoid synovial fluid histidine levels have been reported to be higher than those of matched sera [23].…”