Fig. 8

The effect of synovium on osteochondral plugs was assessed by comparing metabolic signatures in CB and CBS cocultures from donors #1, 7, 11, and 16. a Volcano plot of measured metabolites in spent media of CB and CBS cocultures with statistically significant metabolites marked in red and labeled. Fold change was calculated as metabolite abundance ratios in CB:CBS cocultures. b Relative abundance of the altered metabolites measured on day 2 (green) and day 7 (purple) in CB and CBS groups. c Simplified pathway maps of tryptophan and nicotinamide metabolism. Metabolites measured in this study are shown in bold and two metabolites altered in the CBS cocultures are shown in red. d Temporal abundance changes in metabolites significantly altered with respect to culture condition and time. Results are shown as mean ± SE. Changes in all measured metabolites are shown in gray in the background. CB, intact osteochondral plugs; CBS, osteochondral plugs cocultured with synovium; IDO, indoleamine 2,3-dioxygenase; TDO, tryptophan 2,3-dioxygenase; AFMID, arylformamidase; KYNU, kynureninase; KAT, kynurenine/2-aminoadipate aminotransferase; K3H, kynurenine 3-monooxygenase; 3-HAO, 3-hydroxyanthranilate 3,4-dioxygenase; NNMT, nicotinamide N-methyltransferase