Application of Human Epineural Conduit Supported with Human Mesenchymal Stem Cells as a Novel Therapy for Enhancement of Nerve Gap Regeneration

Maria Siemionow,Katarzyna Kozlowska,Wiktoria Grau-Kazmierczak,Sonia Brodowska,Joanna Cwykiel,Marcin Michal Strojny

doi:10.1007/s12015-021-10301-z

Maria Siemionow, Katarzyna Kozlowska + Show 4 more

Open Access

https://doi.org/10.1007/s12015-021-10301-z

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Abstract

Various therapeutic methods have been suggested to enhance nerve regeneration. In this study, we propose a novel approach for enhancement of nerve gap regeneration by applying human epineural conduit (hEC) supported with human mesenchymal stem cells (hMSC), as an alternative to autograft repair. Restoration of 20 mm sciatic nerve defect with hEC created from human sciatic nerve supported with hMSC was tested in 4 experimental groups (n = 6 each) in the athymic nude rat model (Crl:NIH-Foxn1rnu): 1 - No repair control, 2 - Autograft control, 3 - Matched diameter hEC filled with 1 mL saline, 4 - Matched diameter hEC supported with 3 × 106 hMSC. Assessments included: functional tests: toe-spread and pinprick, regeneration assessment by immunofluorescence staining: HLA-1, HLA-DR, NGF, GFAP, Laminin B, S-100, VEGF, vWF and PKH26 labeling; histomorphometric analysis of myelin thickness, axonal density, fiber diameter and myelinated nerve fibers percentage; Gastrocnemius Muscle Index (GMI) and muscle fiber area ratio. Best sensory and motor function recovery, as well as GMI and muscle fiber area ratio, were observed in the autograft group, and were comparable to the hEC with hMSC group (p = 0.038). Significant improvements of myelin thickness (p = 0.003), fiber diameter (p = 0.0296), and percentage of myelinated fibers (p < 0.0001) were detected in hEC group supported with hMSC compared to hEC with saline controls. At 12-weeks after nerve gap repair, hEC combined with hMSC revealed increased expression of neurotrophic and proangiogenic factors, which corresponded with improvement of function comparable with the autograft control. Application of our novel hEC supported with hMSC provides a potential alternative to the autograft nerve repair.Graphical

Highlights

Peripheral nerve injuries, most commonly caused by traumatic events, result in severe motor disabilities in 2.8% of trauma patients, predominantly in the younger population [1, 2]
Confocal microscopy and flow cytometry confirmed that PKH26 is an efficient dye for human mesenchymal stem cells (hMSC) labeling with low cell toxicity [15]
The graphs represent mean values with SEM, statistical significance is marked with asterisks: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 difference between proximal and distal end of the conduit in the human epineural conduit (hEC) with hMSC group (1.33 ± 0.21 vs. 1.00 ± 0.00, p = 0.0104)

Summary

Introduction

Peripheral nerve injuries, most commonly caused by traumatic events, result in severe motor disabilities in 2.8% of trauma patients, predominantly in the younger population [1, 2]. It is estimated that approximately 100,000 patients undergo peripheral nerve injury surgery every year in the United States and Europe [3, 4]. The optimal surgical management in the repair of peripheral nerve injuries is tension-free repair [3]. Endto-end coaptation of nerve stumps performed under tension causes microvascular flow disruption within the nerve, resulting in ischemia, nerve fibrosis, and eventually poor recovery outcomes [6]. Despite early diagnosis and accurate nerve repair with modern surgical techniques, functional recovery never reaches pre-injury level due to

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