A tissue-engineered bioabsorbable nerve conduit created by three-dimensional culture of induced pluripotent stem cell-derived neurospheres

Acceleration of peripheral nerve regeneration using nerve conduits in combination with induced pluripotent stem cell technology and a basic fibroblast growth factor drug delivery system

“…We used a bioabsorbable polymer tube (outer diameter: 2 mm, inner diameter: 1 mm, and length: 7 mm) that we have described as an artificial nerve conduit for the treatment of peripheral nerve defects. 12,13 This tube consists of two layers: the outer layer was composed of a poly L-lactide (PLA) multifilament fiber mesh and the inner layer was composed of a 50% PLA and 50% poly e-caprolactone (PCL) porous sponge with pores of 10-50 lm (Fig. 1).…”

“…In particular, the PLA and PCL copolymer sponge of the inner layer has a honeycomb structure, into which supportive cells can enter; and growth factors can be added with the delivery system. 12,13 Preparation of nerve conduits coated with neurospheres Mouse iPSc from the iPS-MEF-Ng-178B-5 cell line were provided by RIKEN BRC through the National Bio-Resource Project of MEXT, Japan. 17 The iPSc were cultured and differentiated into primary neurospheres containing neural stem/progenitor cells via embryoid body formation as described previously.…”

“…19 The secondary neurospheres were dissociated into single cells using Try-pLE select (Invitrogen, Osaka, Japan) and were carefully suspended over each conduit at a density of 4,000,000 cells per conduit after prewetting the conduit with 70% ethanol and rinsing with physiologic saline, according to the procedure we reported previously. 13,20 Then, these nerve conduits were placed in Dulbecco's modified Eagle's medium (Invitrogen) supplemented with 10% embryonic stem cellqualified fetal bovine serum (Invitrogen) for 14 days to complete the process of coating the nerve conduits with neurospheres derived from iPSc.…”

“…[9][10][11] We previously developed a bioabsorbable nerve conduit coated with Schwann cells derived from dorsal root ganglia of newborn rats or neurospheres derived from induced pluripotent stem cells (iPSc) that can be used without sacrificing other intact nerves. 12,13 Growth factors including nerve growth factor, neurotrophin-3, and basic fibroblast growth factor (bFGF), which promote axonal outgrowth and neuronal survival, have been added to the nerve conduits directly in solution or through a delivery system. [14][15][16] We believe that a combination of various modifications such as supportive cells and growth factors will ultimately lead to the best results for peripheral nerve regeneration.…”

Application of Human‐Induced Pluripotent Stem Cells (hiPSCs) to Study Synaptopathy of Neurodevelopmental Disorders

“…To fully mimic the natural architecture within the human brain and develop a method to generate human neurons on a large scale for clinical research, a threedimensional (3D) neuronal culture was developed from NPC or rosette aggregates (Mariani et al, 2012;Hogberg et al, 2013;Gouder et al, 2015;Hookway et al, 2016;Chandrasekaran et al, 2017;Hofrichter et al, 2017;Chen et al, 2018b) under the support of 3D scaffolds (Edgar et al, 2017;Gu et al, 2017;Hoveizi et al, 2017;Ishikawa et al, 2017;Lei and Schaffer, 2013;Leong et al, 2016;K. Li et al, 2017;Lu et al, 2012;Medda et al, 2016;Pellett et al, 2015;Uemura et al, 2011;Zhang et al, 2016). Neurons derived from 3D scaffolds, which are mostly made of hydrogel, demonstrated less retention of undifferentiated cells, lower contamination of astrocytes, higher expansion rate, enhanced neuronal differentiation efficiency, and formation of more homogeneous neural tissues containing functional migrating neurons and neuroglia (Edgar et al, 2017;Gu et al, 2017;Ishikawa et al, 2017;Lei and Schaffer, 2013;Lu et al, 2012;Medda et al, 2016;Zhang et al, 2016).…”