Polyhydroxybutyrate (PHB) tubular scaffolds for nerve regeneration

Abstract

Introduction Peripheral nerve injuries remain a challenge in regenerative medicine. Biocompatible polymer tubular nerve guides (GNTs) have been shown to be a promising strategy in the regeneration of total nerve disruption injuries (neurotmesis). The purpose of this systematic literature review was to search and analyze the evidence on the use of the polyhydroxybutyrate (PHB) biopolymer GNT in the regeneration of peripheral nerves in an animal model. Material and method A systematic search was carried out in the search engines: PubMed / MEDLINE, Web of Science, Science Direct, EMBASE and SCOPUS. Using the phrase: (“PHB” OR “P3HB”) AND (“nerve injury” OR “nerve lesion” OR “nerve regeneration”). Between September/2019 and March/2020. In vivo studies with no date limit were considered. Results 193 studies were identified, of which 71 were excluded because they were not related to the topic. Of the remaining 122 studies, 82 were duplicated. Finally, of the remaining 40 studies, 23 were excluded because they were “in vitro” studies and 1 clinical study. Finally 16 studies were reviewed in full text. Conclusions Since the 1990s there have been studies with PHB GNT for nerve injury, primarily in rabbits and rodents. The analysis times and the size of the nerve GAPs do not reveal a standardization. Most of the studies used industrially manufactured PHB sheets. As of 2003, a tendency to include additives (growth factors, neurotrophins and neuroprogenitor cells) to the GNT was noticed. Most of the studies analyzed morphological aspects (macroscopic morphology, histology, immunohistochemistry and ultrastructure), only 3 studies performed functional tests. Overall, the results were positive for the use of GNT made with PHB in animal studies. However, more controlled clinical and functional studies should be performed to confirm the results obtained.