Randomized, Double-Blinded, Controlled Clinical Trial Evaluating The Efficacy Of A Diet Supplemented With Curcuminoids Extract, Hydrolyzed Collagen And Green Tea Extract In Dogs Suffering From Osteoarthritis

Purpose: We have previously demonstrated that a mixture of curcuminoids extract, hydrolyzed collagen and green tea extract (COT) inhibited inflammatory and catabolic mediator’s synthesis by normal bovine and osteoarthritic human chondrocytes. A randomized, double-blinded, placebo-controlled clinical trial was performed to evaluate the efficacy of a diet supplemented with this COT mixture on clinically affected OA dogs. Methods: Forty-two client-owned dogs with OA were randomly assigned to receive for 3 months typical commercial food (n=21) (control) or food supplemented with COT mixture (n=21) (test). At inclusion (T0) and after 3 months of diet (T3), an orthopedic exam was performed by the veterinarian and dogs were scored for lameness (1 to 5), pain at palpation (1 to 5), pain at manipulation (0 to 10) and joint mobility (1 to 5). The most affected limb was determined by orthopedic exam and confirmed by kinetic analysis using a force plate. Ground reaction forces (peak vertical force) (PVF) were recorded using force plate at T0 and T3 with velocity of 1.8 to 2.2 m/s and acceleration-deceleration variation of±0.5 m/s2. Blood samples were collected from the dogs each month to measure OA biomarkers (Coll2-1 and Coll2-1 NO2). Owners evaluated their dog condition by completing a validated Canine Brief Pain Inventory (CBPI) at T0 and T3, assessing pain severity (PS) and pain interference (PI). All data were expressed as mean±standard error mean. Generalized linear model or mixed model were used and analyzed using SAS 9.3 for statistical analysis. A p-value ≤ 0.05 was considered as statistically significant. Results: Concerning the veterinary assessment, there was no statistically significant difference between groups for lameness, pain at palpation and joint mobility. However, there was a beneficial effect for pain at manipulation in the test group (T0: 4.19±0.52; T3: 2.86±0.51, p=0.037) but not in the control group (T0: 3.65±0.56; T3: 3.7±0.4, p=1.000). There was a significant difference between test and control groups for pain at manipulation (p=0.036). There was no significant difference for peak vertical force (PVF) between test and control groups (p=0.148). However, in younger dog’s subgroup (60th percentile: 8.7 years old, mean age: 5.8±0.4 years old, n=11 test + 15 control), the delta T3-T0 for PVF was significantly different between test and control groups (p=0.049). There were no significant differences for Coll2-1 and Coll2-1 NO2 serum concentrations between groups (p=0.705 and p=0.368, respectively). Regarding owner’s assessment, the delta T3-T0 for PS was significantly different between test and control groups (p=0.009). There was no significant difference for PI between test and control groups (p=0.063). In younger dog’s subgroup, PS increased significantly between T0 and T3 in the control group (T0: 2.4±0.52; T3: 3.7±0.59, p=0.007) but slightly decreased in the test group (T0: 1.82±0.41; T3: 1.25±0.43, p=0.463). There was a significant difference in younger dog’s subgroup between test and control groups for PS (p<0.001). Conclusions: Dogs receiving diet were less painful after 3 months. The difference of evolution between groups suggests that a longer treatment may be necessary to reach a stronger effect on other evaluation parameters. Improvement of lameness have been observed, but only in younger dog’s subgroup.