Transplantation of feeder‐free human induced pluripotent stem cell–derived cortical neuron progenitors in adult male Wistar rats with focal brain ischemia

Abstract

The use of human induced pluripotent stem cells (hiPSCs) eliminates the ethical issues associated with fetal or embryonic materials, thus allowing progress in cell therapy research for ischemic stroke. Strict regulation of cell therapy development requires the xeno-free condition to eliminate clinical complications. Maintenance of hiPSCs with feeder-free condition presents a higher degree of spontaneous differentiation in comparison with conventional cultures. Therefore, feeder-free derivation might be not ideal for developing transplantable hiPSC derivatives. We developed the feeder-free condition for differentiation of cortical neurons from hiPSCs. Then, we evaluated the cells' characteristics upon transplantation into the sham and focal brain ischemia on adult male Wistar rats. Grafts in lesioned brains demonstrated polarized reactivity toward the ischemic border, indicated by directional preferences in axonal outgrowth and cellular migration, with no influence on graft survival. Following the transplantation, forelimb asymmetry was better restored compared with controls. Herein, we provide evidence to support the use of the xeno-free condition for the development of cell therapy for ischemic stroke.

Multimodal Therapeutic Effects of Neural Precursor Cells Derived from Human-Induced Pluripotent Stem Cells through Episomal Plasmid-Based Reprogramming in a Rodent Model of Ischemic Stroke

“…In the present study, ep-iPSC-NPC-transplanted animals showed a gradual improvement in their functional deficit during the 11 weeks after transplantation, especially in rotarod, mNSS, and stepping tests. Some studies have used iPSC-NPCs transplanted during the acute phase of stroke [19,21], and other studies found a functional recovery in stroke animals transplanted with iPSCs-NPCs in the subacute phase of stroke (1 week after stroke induction) [15,20,24]. In the present study, ep-iPSC-NPC transplantation in the subacute phase of stroke restored functional defi-cits in stroke animals.…”

“…Previous studies have shown that the engraftment and differential potential of transplanted ESCor iPSC-derived NPCs were highly variable. Approximately 5~30% of cells survive 4 weeks after transplantation, with the numbers of engrafted cells gradually decreasing thereafter [15,[17][18][19][20][33][34][35][36]. Even if the cells had survived, the number of differentiated neurons among the grafted cells was low in this study (less than 10% of engrafted cells).…”

“…Previous studies demonstrated that iPSC-NPC transplantation restored sensorimotor and behavioral function in stroke-damaged animals in various tests including the rotarod, staircase, corridor, beam walking, locomotor activity, adhesive removal, and Morris water maze tests [15,[19][20][21]24]. Although most studies undertook behavioral tests during a short period (about 3~4 weeks) [19][20][21]24], several studies showed a significant behavioral improvement over a long-term period [15,18]. In the present study, ep-iPSC-NPC-transplanted animals showed a gradual improvement in their functional deficit during the 11 weeks after transplantation, especially in rotarod, mNSS, and stepping tests.…”

“…Even if the cells had survived, the number of differentiated neurons among the grafted cells was low in this study (less than 10% of engrafted cells). Although the differential potential of transplanted NPCs varies across studies, about 5~70% of these cells differentiated into mature neurons but rarely differentiated into a glial lineage [15,[17][18][19][20][33][34][35][36]. The variation in engraftment and the differential capacity of NPCs across studies can be accounted for by the use of differences in cell sources, amounts of transplanted cells, delivery route, and the timings of transplantation and histological examination.…”

“…Of these sources, peripheral blood mononuclear cells (PBMCs) have some advantages over other tissues for iPSC generation because they are easily obtained without the need for invasive surgical procedures [8][9][10]. Several in vivo studies of iPSC transplantation in animal stroke models demonstrated an improvement in neurological functions following stroke [11][12][13][14][15][16][17][18][19][20][21]. These results highlight iPSCs as a promising therapeutic option for stroke.…”