We had data on eight metabolic-related diseases (heart disease, hypertension, high blood pressure in pregnancy, high cholesterol, diabetes, stroke, gout and osteoporosis) on all the study participants. The more prevalent diseases in these patients with OA were hypertension Palbociclib PD 0332991 (41.3%), high cholesterol (35%) and diabetes (16.3%). Although group A had a tendency of low prevalence of

these metabolic-related diseases than group B, the differences were not statistically significant (all p>0.05). For the groups B1 and B2, there was no significant difference in age and sex between groups B1 and B2, but BMI in group B1 was higher than that in group B2 (34.2±7.2 vs 29.6±5.3, 0.01

is the use of SF samples rather than plasma or urine samples. Our unpublished data suggested that the metabolite correlation between plasma and SF was only modest (an average correlation coefficient of 0.22). Metabolic profiling in SF reflects directly what is happening in a joint and yields the most accurate, real-time and joint-specific metabolic profile that is relevant to OA.19 On the basis of metabolic profiling of the SFs, we classified 80 patients with OA into two large groups, that is, group A and group B. This is largely due to the difference in concentrations of acylcarnitines. Fasting might be a factor explaining the difference; however, all patients fasted on their surgery dates. When using the ratio of the concentrations of acylcarnitines to free carnitine (C0), group A exclusively had greater ratios than did group B, indicating that two distinguished OA subphenotypes may be related to the carnitine

metabolism pathway. In humans, the major sources of camitine (C0) are de novo synthesis and the diet. In the process of synthesis of carnitine, glycine can be released as a by-product;20 however, there were no significant differences between both groups in the concentration of this metabolite. Carnitine acyltransferases are responsible for the production of acylcarnitines and the value of the acylcarnitines/carnitine ratio can reflect its activity.20 21 In the present study, the ratio of acylcarnitine to carnitine in group A is significantly higher than that of cluster B, which may indicate that the activity AV-951 of acyltransferases is higher in patients of group A than group B. Carnitine and its acyl esters acylcarnitines are essential compounds for the metabolism of fatty acids. Carnitine can assist in the transport and metabolism of fatty acyl-CoA from the cytosol to the mitochondrial matrix, where the enzymes of β-oxidation are located and fatty acids are oxidised as a major source of energy. Inside the mitochondria, carnitine and acyl-CoA are regenerated, and the latter is catabolised in two-carbons units by β-oxidation, with production of acetyl-CoA in normal circumstances.