Proteomic profiling reveals the potential role of allogenic equine platelet-rich plasma and extracellular vesicles in modulating tendon inflammation and repair.

This research studied the protein composition of equine platelet-rich plasma (PRP) and its derived extracellular vesicles (EVs), as well as their potential role in modulating tendon inflammation and repair in horses.

Objective of the Study

The primary objective of the study was to understand the protein composition of equine platelet-rich plasma (PRP) and PRP-derived extracellular vesicles (EVs). The researchers aimed to assess the potential implications of these compositions on influencing tendon inflammation in vitro (in a controlled lab environment).

Methodology of the Study

• The researchers collected plasma samples from three adult horses between December 2022 and May 2023.
• The plasma was isolated via a double centrifugation process and PRP was produced using a commercial kit.
• Extracellular vesicles (EVs) were isolated from the PRP through a method called differential ultracentrifugation and characterized using a test known as a tetraspanin assay.
• Equine tenocyte fibroblasts from six horses were then artificially stimulated with IL-1β and tumor necrosis factor-α to induce inflammatory conditions simulating an injury, before being treated with the prepared PRP or PRP-derived EVs.
• A proteomic analysis was performed using a data-dependent LC-MS-MS method to study the protein contents.

Findings of the Study

• The researchers found that compared to plasma, PRP and PRP EVs were rich in proteins related to cellular waste disposal and inhibition of lipid metabolism.
• The experimental conditions significantly influenced the levels of 18 proteins in tenocyte fibroblasts.
• The treatment of PRP and PRP EVs led to a decrease in the abundance of Collagen type 1 α chain 1, which has implications on collagen metabolism, a critical aspect of tendon repair.
• An increase in a protein called sequestosome 1 was observed upon treatment. This increase could either enhance inflammation or mitigate it through a process called autophagy-mediated degradation.

Conclusion and Future Implications

• The study concluded that PRP EVs influence the proteome (complete set of proteins produced by a biological system) of inflammatory tenocyte fibroblasts, which could contribute to the therapeutic effects of PRP.
• Understanding the protein compositions of PRP and PRP-derived EVs could help optimize PRP-based treatments for equine tendon injuries. This optimization could lead to more consistent and effective therapies, reducing the chances of reinjury and improving the overall healing process of tendons.