Discussion
Synovial inflammation, OA, musculoskeletal and connective tissue disorders, pain
MUSCULOSKELETAL AND CONNECTIVE TISSUE DISORDERS NEC, MUSCULOSKELETAL AND CONNECTIVE TISSUE DISORDER
This pilot, randomized, placebo-controlled study was the first clinical trial to evaluate the efficacy of HC-II, a newly developed chicken-derived CH, alone and in combination with chicken essence, a food supplement that has been consumed in Asia for a long time. The main finding was that HC-II had a fast-acting effect on reducing pain after 14 days, as measured using the VAS. Synovial inflammation is associated with joint pain in patients with OA [WOMAC total score improved in all four groups after 24 weeks. However, the differences among groups was not significant. This result might be attributed to the following causes: (1) the psychological effects of supplementation and study regimen (exercise, consultations, and counseling) and placebo effects, (2) the physiological benefits of resistance training and lifestyle modifications, or (3) the patients’ characteristics. EC-HC-II differs from other supplements enriched with type II collagen in terms of ingredients (chicken essence), amount of collagen, and format (liquid). Other factors such as food, exercise, and environmental factors (eg, amount of sunlight and physical activities) may explain the different outcomes between our study and other studies of supplements enriched with type II collagen. With regard to patient characteristics, this study enrolled mostly patients with early or mild OA (Kellgren–Lawrence grade 1: > 68% of patients) who were not receiving OA treatment; therefore, they may have failed to exhibit significant improvements in symptoms after supplementation.Previous trials investigating the role of collagen in treating OA have reported contrasting results. When compared with glucosamine HCl [After 24 weeks, the EC-HC-II group exhibited higher FFM than the glucosamine HCl and placebo groups and higher grip strength than the glucosamine HCl group. Some plausible mechanisms of both EC and collagen peptides have been indicated in studies. An animal study demonstrated that EC improved exercise performance and endurance capacity due to its antioxidant properties and antifatigue effects [Systematic reviews have concluded that resistance training is effective in managing the symptoms of OA by improving joint function and reducing pain [In addition, our study also showed that taking EC-HC-II resulted in greater improvement in left hip bone mass than taking a placebo or glucosamine HCl did among participants who undertook minimal resistance training. EC-HC-II contained a novel peptide, Gly-Pro-Glu-Gly-Ala-Pro-Gly-Lys-Asp, which was found to reduce bone resorption in an in vitro model measuring bone matrix collagen degradation by differentiated osteoclasts. We hypothesize that this is an underlying mechanism associated with increased bone mass (unpublished data). To our knowledge, only two clinical studies have shown that relative to calcitonin and calcium plus vitamin D, collagen peptides contribute more to the inhibition of bone collagen breakdown and loss of bone mineral density, respectively [This study has some limitations. First, physical activity was not measured at baseline, because participants, mostly aged 50 to 60 years, were considered unlikely to have undertaken any form of resistance exercise program prior to entering the study. Nevertheless, future studies can more comprehensively evaluate the effects of baseline activity level on study outcomes. Second, because the study was designed to use WOMAC score, the sample size may be inadequate for other endpoints and the heterogeneity of the small cohort might cause biases or variations in results. A post hoc analysis adjusted for the characteristics of participants within a more defined cohort showed that CH-containing products reduce OA-derived pain and increase muscle mass and strength. These promising results warrant further verification in a large-scale study. Third, the study period of 6 months may have been too short to detect a clinically significant change in joint and bone conditions. Thus, further long-term studies should be conducted to validate the effects of EC-HC-II and HC-II on locomotor function. Fourth, female predominance (84.8% of patients) might limit the generalizability of our results. Nevertheless, prevalence of knee OA is higher in women than men [EC-HC-II and HC-II were well-tolerated by participants, and no safety problems were detected. The incidence of musculoskeletal and connective tissue disorders was higher in the placebo group than in the supplement groups. Musculoskeletal and connective tissue disorders reflect joint, muscle, and bone health. Thus, we inferred that EC-HC-II and HC-II might have protective effects on bones, muscles, and joints. Nevertheless, further studies are necessary to validate these findings.