Allogenic platelet-rich plasma and platelet-rich plasma extracellular vesicles alter the proteome of tenocytes in an in vitro equine model of tendon inflammation: A pilot study
Authors: Emily J Clarke, Anders Jensen, Alexandra M Gillen, David Bardell, Mark Senior, James R. Anderson, Mandy J. Peffers
Journal: bioRxiv
Summary
# Editorial Summary: Platelet-Rich Plasma Extracellular Vesicles and Tendon Inflammation Tendon injuries carry a frustratingly high reinjury risk in horses, and whilst platelet-rich plasma (PRP) therapeutics show clinical promise, their variable composition and inconsistent outcomes have hampered widespread adoption. Clarke and colleagues conducted a proteomic analysis of allogenic PRP and PRP-derived extracellular vesicles (EVs)—the cellular communication intermediaries thought to mediate much of PRP's biological activity—using an in vitro model of inflamed equine tenocytes. Inflammatory stimulation combined with PRP or PRP-EV treatment altered the expression of 18 proteins in tenocytes, with particularly notable changes in collagen metabolism (col1a1) and nuclear factor kappa B signalling pathways, suggesting that PRP-derived EVs actively modulate the inflammatory response rather than simply delivering growth factors. The enrichment of proteins related to cellular waste disposal and lipid metabolism in PRP-EVs compared to plasma-derived EVs points towards a mechanistic basis for PRP efficacy that extends beyond soluble growth factors. These preliminary findings warrant further investigation into EV composition as a quality marker for PRP preparations and support the hypothesis that EV standardisation could improve the consistency and reproducibility of PRP treatment outcomes in clinical equine practice.
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Practical Takeaways
- •PRP efficacy may depend on extracellular vesicle content rather than soluble factors alone, suggesting standardization of EV composition could improve treatment consistency and outcomes
- •Variable clinical results from PRP treatments may be explained by differences in EV concentration and protein composition between commercial kits—consider batch characterization for higher-value cases
- •This foundational work supports further investigation into EV-enriched preparations as potentially superior alternatives to standard PRP for tendon injuries, though clinical efficacy still requires in vivo validation
Key Findings
- •PRP contained 575 quantifiable proteins while PRP-derived extracellular vesicles contained 209 proteins with enrichment in cellular waste disposal and lipid metabolism inhibition pathways
- •Inflammatory stimulation and PRP or PRP-EV treatments significantly altered abundance of 18 proteins in equine tenocytes including col1a1 and sequestosome 1
- •PRP-derived extracellular vesicles demonstrated capacity to influence inflammatory tenocyte proteome, suggesting EVs may be crucial to PRP therapeutic efficacy
- •Proteomic differences between PRP and plasma-derived products suggest enriched composition contributes to biological activity in hemoderivative therapeutics