Kynurenine inhibits chondrocyte proliferation and is increased in synovial fluid of patients with septic arthritis.
Kynurenine, the major degradation product of tryptophan has been shown to directly damage various tissues. Its potential contribution to septic arthritis is unknown. In this study, we analyzed the putative diagnostic value of kynurenine for bacterial joint infection and its potential harmful effects on cartilage. In a prospective study 41 patients with a joint effusion who had undergone arthrocentesis were included. Tryptophan and kynurenine levels from synovial fluid were quantified by HPLC. Diagnostic value of kynurenine was evaluated and its effects on the proliferation of the chondrocyte cell line ATDC5 were determined. Synovial fluid kynurenine values from patients with septic arthritis (4.1 ± 0.8 µmol/L, n = 9) were significantly increased compared to patients with non-infectious inflammatory arthropathy (1.8 ± 0.2 µmol/L, n = 17) or osteoarthritis (1.2 ± 0.1 µmol/L, n = 15, p < 0.01). At a cut-off value of 2.28 µmol/L kynurenine had a sensitivity of 0.89 and a specificity of 0.87. Further, kynurenine inhibited chondrocyte (ATDC5) cell proliferation in a dose-dependent manner. Septic arthritis is associated with significantly increased values of synovial kynurenine. Furthermore kynurenine inhibits proliferation of chondrocytes, which strongly suggests a pathophysiological effect of kynurenine on cartilage in inflammatory arthropathies.
Lögters
Tim T
TT
Department of Trauma and Hand Surgery, University Hospital Düsseldorf, Moorenstr 5, 40225 Düsseldorf, Germany. tim.loegters@uni-duesseldorf.de
Laryea
Maurice D
MD
Jäger
Marcus
M
Schädel-Höpfner
Michael
M
Windolf
Joachim
J
Flohé
Sascha
S
Altrichter
Jens
J
Scholz
Martin
M
Paunel-Görgülü
Adnana N
AN
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001170:Arthritis, Infectious / Q000378:metabolism* / Q000382:microbiology; D002097:C-Reactive Protein / Q000032:analysis; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000502:physiology*; D005260:Female; D006801:Humans; D007737:Kynurenine / Q000032:analysis / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D013582:Synovial Fluid / Q000737:chemistry*; D014364:Tryptophan / Q000032:analysis
D007737:Kynurenine; D014364:Tryptophan; D002097:C-Reactive Protein