Clinical outcomes following intra-articular injection of autologous adipose-derived mesenchymal stem cells for the treatment of osteoarthritis in dogs characterized by weight-bearing asymmetry

Abstract

Aims: This study investigates the effects of intra-articular injection of adipose-derived mesenchymal stem cells (AdMSCs) and platelet-rich plasma (PRP) on lameness, pain, and quality of life in osteoarthritic canine patients.

Methods: With informed owner consent, adipose tissue collected from adult dogs diagnosed with degenerative joint disease was enzymatically digested and cultured to passage 1. A small portion of cells (n = 4) surplus to clinical need were characterized using flow cytometry and tri-lineage differentiation. The impact and degree of osteoarthritis (OA) was assessed using the Liverpool Osteoarthritis in Dogs (LOAD) score, Modified Canine Osteoarthritis Staging Tool (mCOAST), kinetic gait analysis, and diagnostic imaging. Overall, 28 joints (25 dogs) were injected with autologous AdMSCs and PRP. The patients were followed up at two, four, eight, 12, and 24 weeks. Data were analyzed using two related-samples Wilcoxon signed-rank or Mann-Whitney U tests with statistical significance set at p < 0.05.

Results: AdMSCs demonstrated stem cell-like characteristics. LOAD scores were significantly lower at week 4 compared with preinjection (p = 0.021). The mCOAST improved significantly after three months (p = 0.001) and six months (p = 0.001). Asymmmetry indices decreased from four weeks post-injection and remained significantly lower at six months (p = 0.025).

Conclusion: These improvements in quality of life, reduction in pain on examination, and improved symmetry in dogs injected with AdMSCs and PRP support the effectiveness of this combined treatment for symptom modification in canine OA for six months. Cite this article: Bone Joint Res 2021;10(10):650-658.

Keywords: Adipose tissue; Flow cytometry; Intra-articular injection; Mann-Whitney U tests; Osteoarthritis; Osteoarthritis (OA); Platelet-rich plasma; Stem cells; adipose-derived mesenchymal stem cells; clinical outcomes; gait analysis; platelet-rich plasma (PRP); stem cells.

Fig. 1

a) Alizarin Red, b) Oil Red O, and c) Alcian Blue stain for adipose-derived mesenchymal stem cells and their negative controls differentiated to d) bone, e) fat, and f) cartilage, respectively, after 21 days (n = 4).

Fig. 2

Flow cytometry results for adipose-derived mesenchymal stem cells. The cells were negative for CD34 and CD45 and highly expressed CD90 (n = 4).

Fig. 3

Graphs showing: a) the mean Liverpool Osteoarthritis in Dogs (LOAD) score taken before injection (on the day of the injection) up to six months; and b) the mean Modified Canine Osteoarthritis Staging Tool (mCOAST) score assessed on the day of injection (preinjection), and three months and six months post-injection. The LOAD score was shown to decrease up to six months, demonstrating improved mobility and pain scores based on owner assessment. *p < 0.05, Mann-Whitney U test. For LOAD analysis: preinjection (n = 17), week 2 (n = 10), week 4 (n = 13), week 8 (n = 13), week 12 (n = 13), and week 24 (n = 8). For COAST analysis: preinjection (n = 16), week 12 (n = 16), and week 24 (n = 13).

Fig. 4

The asymmetry index calculated using the peak vertical force (PVF), calculated from the injected limb and the contralateral uninjected joint. Asymmetry index is a percentage, calculated by finding the difference in PVF between the treated and untreated limb and dividing by the sum of PVF for the same limbs. *p < 0.05, Mann-Whitney U test. Preinjection (n = 28), week 2 (n = 10), week 4 (n = 15), week 8 (n = 18), week 12 (n = 16), and six months (n = 9).