Biocompatibility of hydrogel derived from equine tendon extracellular matrix in horses subcutaneous tissue
Authors: Thiago De Castilho, G. Rosa, F. Stievani, E. Apolônio, J. P. Pfeifer, Vittoria Altheman, Valéria Palialogo, Nilton José Dos Santos, C. Fonseca‐Alves, A. Alves
Journal: Frontiers in Bioengineering and Biotechnology
Summary
# Editorial Summary Equine tendon injuries represent a significant clinical challenge, and recent advances in regenerative medicine have focused on developing injectable scaffolds derived from native extracellular matrix (ECM) rather than synthetic alternatives, which have shown inferior outcomes. Researchers administered three subcutaneous injections of an equine tendon ECM-derived hydrogel to six horses, with saline controls, then assessed biocompatibility through thermographic imaging, mechanical nociception testing, histopathological examination, and transmission electron microscopy at 7, 14, and 56 days post-injection. The hydrogel proved easily injectable with good general tolerability, though thermography detected elevated local temperatures within 12 hours and von Frey testing revealed altered nociceptive thresholds at 6 hours, 21 days, and 28 days; importantly, this transient inflammatory phase resolved by day 14, with tissue integration progressing thereafter. Histological findings demonstrated a predictable inflammatory response at day 7 (consistent with normal wound healing) that had substantially resolved by day 14, whilst transmission electron microscopy showed declining inflammatory cell infiltration despite immunohistochemical evidence of elevated inflammatory mediators at the two-week timepoint. For practitioners considering ECM-based therapeutic options, these results suggest the hydrogel could be a viable injectable scaffold for tendon repair protocols, though the initial inflammatory response and altered mechanoreception warrant careful patient selection and post-treatment monitoring, particularly in performance animals where transient sensitivity changes might affect athletic function.
Read the full abstract on PubMed
Practical Takeaways
- •ECM-derived hydrogel scaffolds show promise as injectable treatment for tendon injuries with good biocompatibility and predictable integration timeline (day 14+)
- •Expect transient local inflammatory response and mild sensory changes in first 2 weeks post-injection; monitor for heat/sensitivity in initial 12 hours
- •This early-stage research suggests ECM hydrogels may outperform synthetic polymers, but clinical efficacy for actual tendon repair/healing remains to be determined in larger studies
Key Findings
- •Equine tendon ECM-derived hydrogel triggered temporary local inflammatory response resolved by day 14
- •Thermographic analysis showed temperature increase in treated groups within 12 hours compared to saline control
- •Von Frey nociceptive threshold testing showed significant differences between treated and control groups at 6h, 21 days, and 28 days
- •Hydrogel demonstrated tissue integration beginning at day 14 with stable host physical condition throughout study period