Exosome therapy for knee osteoarthritis: a network meta-analysis based on rat models
In brief
High-dose human stem-cell exosomes cut cartilage damage scores by four units in rats
In 27 randomized rat studies, exosome injections from human amniotic fluid or umbilical-cord stem cells at doses of 100 µg or more lowered histologic cartilage damage scores by roughly four standard-deviation units, boosted type II collagen, and suppressed IL-1β. Effects grew with higher doses, but publication-bias adjustments suggest the true benefit may be smaller, underscoring the need for more rigorous preclinical work.
- Journal
- Stem cells translational medicine (Q1)
- Published
- 18 August 2026
- Study design
- Systematic review / meta-analysis of RCTs
- Evidence level
- Level 1, High (CEBM 1a)
- Authors
- Yixiang Zhao, Haochuan You, Xiuyuan Wang, Xiping Dou, Jiangying Zhang, Yuzhe He, et al.
- PMID
- 42613148
- DOI
- 10.1093/stcltm/szag069
Why clinicians should know about it
- Picked for Rheumatology (top studies of the week, 23 August 2026): Preclinical rat RCT, limited clinical relevance
Abstract
OBJECTIVE: To compare the therapeutic effects of exosomes from different cell sources and doses in rat knee osteoarthritis models using network meta-analysis, and to identify potential optimal strategies for preclinical optimization and clinical hypothesis generation. METHODS: A systematic search of PubMed, Web of Science, Embase, and Scopus identified 27 eligible randomized controlled trials (456 rats). Traditional random-effects meta-analysis and frequentist network meta-analysis were conducted. Treatments were ranked using SUCRA values. RESULTS: A total of 27 studies were included, comprising 456 rats. Traditional meta-analysis revealed that exosome therapy significantly reduced joint cartilage histopathological damage (reduced OARSI score: SMD = -3.78, 95% CI: -4.76, -2.80), promoted type II collagen synthesis (SMD = 3.41, 95% CI: 1.87, 4.95), and suppressed the expression of the inflammatory cytokine IL-1β (SMD = -3.26, 95% CI: -4.08, -2.44). Network meta-analysis further indicated that under high-dose conditions (≥100 μg), exosomes derived from human amniotic fluid stem cells (hAFSCs-Exo) and human umbilical cord mesenchymal stem cells (hUCMSCs-Exo) ranked highest in relative efficacy for improving the OARSI score. hUCMSCs-Exo also demonstrated the most potent anti-inflammatory effect by reducing IL-1β. Overall, exosome therapy exhibited a dose-related trend in efficacy, with high-dose transplantation showing higher probabilistic SUCRA rankings across most outcome measures. However, assessment of publication bias revealed marked asymmetry; after trim-and-fill correction, the effect size for type II collagen expression decreased from SMD = 3.41 to 1.26, suggesting that the magnitude of the treatment effect may have been overestimated. This overestimation reduces the certainty of the observed treatment effects. Despite the presence of publication bias and methodological limitations, the main conclusions remained statistically robust after trim-and-fill correction. CONCLUSION: Current evidence from rat models suggests that exosome therapy may substantially ameliorate the pathological progression of KOA, with exosomes derived from early developmental tissues, particularly hAFSCs-Exo and hUCMSCs-Exo, showing favorable chondroprotective and anti-inflammatory effects in the probabilistic ranking when administered at high doses. Nevertheless, the findings from publication bias and trim-and-fill analyses indicate that the existing effect sizes are likely overestimated. These results require confirmation in larger-scale, methodologically more rigorous preclinical studies.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.