ObjectiveTo investigate host and gut-microbiota related Tryptophan metabolism in hand osteoarthritis (HOA).MethodsThe baseline serum concentration of 20 Tryptophan metabolites was measured in 416... Show moreObjectiveTo investigate host and gut-microbiota related Tryptophan metabolism in hand osteoarthritis (HOA).MethodsThe baseline serum concentration of 20 Tryptophan metabolites was measured in 416 HOA patients in a cross-sectional analysis of the DIGICOD cohort. Tryptophan metabolites levels, metabolite-ratios and metabolism pathway activation were compared between erosive (N = 141) and non-erosive HOA (N = 275) by multiple logistic regressions adjusted on age, BMI and sex. The association between Tryptophan metabolite levels and HOA symptoms was investigated by a Spearman's rank correlation analysis.ResultsFour serum Tryptophan metabolites, eight metabolite ratios and one metabolism pathway were associated with erosive HOA. Erosive HOA was negatively associated with Tryptophan (odds ratio (OR) = 0.41, 95% confidence interval [0.24–0.70]), indole-3-aldehyde (OR = 0.67 [0.51–0.90]) and 3-OH-anthranilic acid (OR = 1.32 [1.13–1.54]) and positively with 5-OH-Tryptophan levels (OR = 1.41 [1.13–1.77]). The pro-inflammatory kynurenine–indoleamine 2,3-dioxygenase pathway was upregulated in erosive HOA (OR = 1.60 [1.11–2.29]). Eleven metabolites were correlated with HOA symptoms and were mostly pain-related. Serotonin and N-acetyl serotonin levels were negatively correlated with number of tender joints. Indole-3-aldehyde level was negatively correlated and 3-OH-anthranilic acid, 3-OH-kynurenine and 5-OH-Tryptophan levels were positively correlated with number of patients-reported painful joints. Quinolinic acid and 3-OH-kynurenine levels correlated positively with AUSCAN pain.ConclusionsTryptophan metabolites disturbance is associated with erosive HOA and pain and emphasize the role of low-grade inflammation and gut dysbiosis in HOA. Show less
Kroon, F.P.B.; Beest, S. van; Ermurat, S.; Kortekaas, M.C.; Bloem, J.L.; Reijnierse, M.; ... ; Kloppenburg, M. 2018
Obesity is a major risk factor of osteoarthritis development and progression. Theoretically, obesity is a factor that can be modified. While obesity epidemic is difficult to reverse because we live... Show moreObesity is a major risk factor of osteoarthritis development and progression. Theoretically, obesity is a factor that can be modified. While obesity epidemic is difficult to reverse because we live in lipogenic environment, personal approach in modify obesity may avail. Therefore, understanding how obesity leads to osteoarthritis is needed. The first three chapters of this thesis investigate several aspects of osteoarthritis: what structures are damaged, what factors are associated with worsening of osteoarthritis and how to measure worsening of osteoarthritis. The other four chapters investigate the link between obesity and osteoarthritis. We show that obesity is associated with hand osteoarthritis. Since we do not walk on our hand, there must be another factor than mechanical that cause joint damage in osteoarthritis. One of the factors is adipokines, protein produced mainly by fat tissue. We showed that adiponectin, one of the adipokines, prevents worsening of hand osteoarthritis. We concluded that obesity plays role in osteoarthritis not only due to added mechanical force but also due to added metabolic force (adipokines). These adipokines might be used as target in modifying the effect of obesity on osteoarthritis. However, we still need more studies on how obesity links with osteoarthritis Show less
