Influence of Supplements and Drugs used for the Treatment of Musculoskeletal Disorders on Adult Human Tendon-Derived Stem Cells

Background. Recent findings indicate that the connective tissue of tendons hosts cells that can self-renew and are multipotent. Even if these cells seemingly fail to accomplish tendon regeneration in pathological conditions, their identification and characterization represents a milestone in the research and development of new biological therapies for tendinopathies. Methods. We isolated the adult human tendon-derived stem cells (hTDSCs) from the fragments of patellar or calcaneal tendons and characterized these cells in vitro by immunochemistry and histochemistry. Subsequently, the MTT test and Trypan Blue were used for the evaluation of cytotoxicity of the supplements/drugs commonly used for the treatment of musculoskeletal disorders: Curcumin, Hyaluronic Acid, Palmitoylethanolamide, Diclofenac sodium, Triamcinolone acetonide and Thiocolchicoside. Results. Cells obtained by outgrowth expressed mesenchymal markers, were clonogenic and differentiated into chondroblasts, osteoblasts and adipocytes. High concentrations of the anti-inflammatory glucocorticoid Triamcinolone and the analgesic fatty-acid amide Palmitoylethanolamide significantly reduced cell viability. Only curcumin had a positive effect on cell survival, both in the normal and oxidative stress conditions. Conclusions. Adult human tendons posses stem cells. The influence of several drugs or supplements used for the treatment of musculoskeletal disorders should be taken into consideration in order to take the full advantage of the healing properties of stem cells within tendons.