Comparison of Collagen and Human Amniotic Membrane Nerve Wraps and Conduits for Peripheral Nerve Repair in Preclinical Models: A Systematic Review of the Literature

Abstract

Introduction Collagen and human amniotic membrane (hAM) are Food and Drug Administration (FDA)-approved biomaterials that can be used as nerve wraps or conduits for repair of peripheral nerve injuries. Both biomaterials have been shown to reduce scarring and fibrosis of injured peripheral nerves. However, comparative advantages and disadvantages have not been definitively shown in the literature. The purpose of this systematic review is to comprehensively evaluate the literature regarding the roles of hAM and collagen nerve wraps and conduits on peripheral nerve regeneration in preclinical models. Methods The MEDLINE database was queried using the PubMed search engine on July 7, 2019, with the following search strategy: (“amniotic membrane” OR “amnion”) OR (“collagen conduit” OR “nerve wrap”)] AND “nerve.” All resulting articles were screened by two independent reviewers. Nerve type, lesion type/injury model, repair type, treatment, and outcomes were assessed. Results Two hundred and fifty-eight articles were identified, and 44 studies remained after application of inclusion and exclusion criteria. Seventeen studies utilized hAM, whereas 27 studies utilized collagen wraps or conduits. Twenty-three (85%) of the collagen studies utilized conduits, and four (15%) utilized wraps. Six (35%) of the hAM studies utilized conduits and 11 (65%) utilized wraps. Two (9%) collagen studies involving a conduit and one (25%) involving a wrap demonstrated at least one significant improvement in outcomes compared with a control. While none of the hAM conduit studies showed significant improvements, eight (73%) of the studies investigating hAM wraps showed at least one significant improvement in outcomes. Conclusion The majority of studies reported positive outcomes, indicating that collagen and hAM nerve wraps and conduits both have the potential to enhance peripheral nerve regeneration. However, relatively few studies reported significant findings, except for studies evaluating hAM wraps. Preclinical models may help guide clinical practice regarding applications of these biomaterials in peripheral nerve repair.

General consensus on multimodal functions and validation analysis of perinatal derivatives for regenerative medicine applications

“…hAM has been evaluated as nerve wraps or conduits for the repair of peripheral nerve injuries in vitro in human and pre-clinical models ( Wolfe et al, 2022 ) and humans ( Fénelon et al, 20212021 ). hAM alone or associated with adult or perinatal cells ( Fénelon et al, 2021 ), such as allogeneic hUC-MSC ( Li et al, 2013 ), has been evaluated.…”

“…Histological (HE, Toluidine Blue, Oil Red O staining) or immunohistological analysis have allowed qualitative/stereological analysis of the gross morphology or microstructure of: 1) nerve parameters such as axon regeneration—increase of axon size—number—diameter—density, axonal migration, myelin sheath thickness or nerve fiber diameter; 2) muscle mass innervated by the transected then repaired nerve and 3) muscle atrophy attenuation ( Bour geois et al, 2019 ; Bojanic et al, 2020 ; Ülger et al, 2021 ; Wolfe et al, 2022 ). Retrograde axonal transport was estimated through fluorogold-labeled neuron counts after hUC-MSC grafting ( Bojanic et al, 2020 ).…”

“…Neuromorphometry employs transmission electron microscopy or high-resolution light microscopy in which the number of myelinated fibers, the total number of nerve fibers, axon diameter, myelin thickness, G-ratio, and N-ratio were the most commonly reported outcomes ( Marchesini et al, 2018 ; Wolfe et al, 2022 ).…”

“…Functional motor assessments included various types of static or dynamic gait analysis, strength measurements, or analysis of other specific behavior ( Su et al, 2018 ; Bour geois et al, 2019 ; Ülger et al, 2021 ; Wolfe et al, 2022 ). The sciatic functional index (SFI) is an index of the functional condition of rat sciatic nerve based on measurements made from walking tracks ( Ülger et al, 2021 ).…”

“…The sciatic functional index (SFI) is an index of the functional condition of rat sciatic nerve based on measurements made from walking tracks ( Ülger et al, 2021 ). Functional sensory outcomes measures also included withdrawal latency reflex (WRL) tests, tactile tests, or heat cutaneous allodynia ( Wolfe et al, 2022 ).…”