# Application of Human Epineural Patch (hEP) as a Novel Strategy for Nerve Protection and Enhancement of Regeneration After Nerve Crush Injury

## TL;DR

This study shows that a human epineural patch helps nerves regenerate better than a human amniotic membrane after injury in rats.

## Contribution

The human epineural patch is introduced as a novel, off-the-shelf strategy for nerve regeneration.

## Key findings

- hEP improved motor recovery, axonal density, and muscle atrophy compared to hAM and controls.
- hEP showed higher expression of neurogenic and angiogenic markers, indicating regenerative potential.
- Both hEP and hAM were non-immunogenic, as shown by low HLA-DR and HLA-I expression.

## Abstract

Background: Numerous experimental studies aim to improve outcomes of peripheral nerve repair following trauma. This study evaluates the efficacy of the human epineural patch (hEP) compared to the human amniotic membrane (hAM) in promoting nerve regeneration following sciatic nerve crush injury. Methods: Thirty-six athymic nude rats were divided into three groups (n = 12 per group) following nerve crush: (1) an unprotected injury site; (2) crush injury wrapped with hEP; and (3) crush injury wrapped with hAM. Animals were assessed over 6 or 12 weeks post-injury. Evaluations included motor recovery (Toe-Spread test), sensory recovery (Pinprick test), muscle denervation atrophy (the gastrocnemius muscle index (GMI)), histomorphometry (myelin thickness, axonal density, fiber diameter, and percentage of myelinated fibers), and immunofluorescence (GFAP, Laminin B, NGF, S-100, VEGF, vWF, HLA-DR, and HLA-I) assessments. Results: The hEP group showed superior motor recovery, axonal density and higher GMI values compared to the hAM and control groups. The increased expression of neurogenic and angiogenic markers highlighted its neuroregenerative potential. Negligible HLA-DR and HLA-I expression confirmed the lack of hEP and hAM immunogenicity. Conclusions: The application of hEP following sciatic nerve crush injury facilitated nerve regeneration, improved functional outcomes, and offered a viable alternative to hAM. Structural stability and the regenerative capacity position hEP as a new, promising off-the-shelf product for nerve regeneration.