Summary

In this study we are comparing two different types of ECM (to evaluate if the source tissue matters) and exosomes alone with a control group and with currently widely used PRP treatment for tendinopathy.

Abstract

Introduction

Tendon injuries are common problem and result in more than two million doctor consultations per year in the US alone. Overuse tendon injury accounts for approximately 50% of all sport related injuries and nearly half of all job-related illness in the USA.
Although the Achilles tendon is the thickest and the strongest tendon in human body, it is one of the most frequently injured. Tendinopathy is the most common pathological condition in the Achilles tendon and represents about 65% of its disorders. There is no consensus regarding the best method for management of the Achilles tendon pathologies. Individual preferences, drawn from experience and study most commonly determine the course of treatment. The aim of the present study is to objectively and quantitatively compare the results of four different treatments in a rodent model of experimentally induced tendinopathy. The rat collagenase tendinopathy model most closely mimics tendinopathy in humans.
Bioscaffolds and hydrogels composed of extracellular matrix (ECM) have been successfully used to mitigate inflammation, recruit endogenous stem/progenitor cells, and modulate the immune system to facilitate rapid and effective tissue regeneration in a variety of soft tissue locations. Bioactive signaling molecules that promote tissue regeneration, either released from matrix proteins or delivered by matrix bound nano-vesicles (MBVs) are believed to be responsible for regenerative proprieties of ECM. The present study compares ECM derived from 2 tissue sources with ECM-derived MBVs and platelet rich plasma (PRP) for their ability to promote structural and functional restoration of tendons following collagenase-induced tendinopathy.

Materials And Methods

The rat collagenase-induced tendinopathy model is used in this study. Tendinopathy is produced in 100 Sprague-Dawley male rats by injection with 10% collagenase into the right Achilles tendon. Fourteen (14) days later, the rats were randomly divided into 5 equal groups: group 1 – control group, was injected with saline solution. Group 2 was injected with porcine urinary bladder - derived ECM hydrogel. Group 3 was injected with porcine tendon-derived ECM gel. Group 4 was injected with PRP. Group 5 was injected with ECM derived MBVs. The present study therefore compares ECM treatment with widely used PRP treatment.
Animals were sacrificed 7 (n=10 for each group at each time point) and 24 days after treatment and evaluated by both histomorphologic methods and biomechanical testing methods to determine tendon strength.

Results

Significant differences were found between treatment groups in both histhopathologic and mechanical The temporospatial distribution of recruited mononuclear cells within the ECM treated and MBV treated groups recapitulated the findings observed in soft tissue locations in previous studies. The type and quality of collagen differed among treatment groups by day 24.

Conclusions

ECM and MBVs show promise for treatment of tendinopathy, with the potential for tissue regeneration rath