Optimal electrical stimulation boosts stem cell therapy in nerve regeneration

Abstract

Peripheral nerve injuries often lead to incomplete recovery and contribute to significant disability to approximately 360,000 people in the USA each year. Stem cell therapy holds significant promise for peripheral nerve regeneration, but maintenance of stem cell viability and differentiation potential in vivo are still major obstacles for translation. Using a made-in-house 96-well vertical electrical stimulation (ES) platform, we investigated the effects of different stimulating pulse frequency, duration and field direction on human neural crest stem cell (NCSC) differentiation. We observed dendritic morphology with enhanced neuronal differentiation for NCSCs cultured on cathodes subject to 20 Hz, 100μs pulse at a potential gradient of 200 mV/mm. We further evaluated the effect of a novel cell-based therapy featuring optimized pulsatile ES of NCSCs for in vivo transplantation following peripheral nerve regeneration. 15 mm critical-sized sciatic nerve injuries were generated with subsequent surgical repair in sixty athymic nude rats. Injured animals were randomly assigned into five groups (N = 12 per group): blank control, ES, NCSC, NCSC + ES, and autologous nerve graft. Optimized ES was applied immediately after surgical repair for 1 h in ES and NCSC + ES groups. Recovery was assessed by behavioral (CatWalk gait analysis), wet muscle-mass, histomorphometric, and immunohistochemical analyses at either 6 or 12 weeks after surgery (N = 6 per group). Gastrocnemius muscle wet mass measurements in ES + NCSC group were comparable to autologous nerve transplantation and significantly higher than other groups (p < 0.05). Quantitative histomorphometric analysis and catwalk gait analysis showed similar improvements by ES on NCSCs (p < 0.05). A higher number of viable NCSCs was shown via immunochemical analysis, with higher Schwann cell (SC) differentiation in the NCSC + ES group compared to the NCSC group (p < 0.05). Overall, ES on NCSC transplantation significantly enhanced nerve regeneration after injury and repair, and was comparable to autograft treatment. Thus, ES can be a potent alternative to biochemical and physical cues for modulating stem cell survival and differentiation. This novel cell-based intervention presents an effective and safe approach for improved outcomes after peripheral nerve repair.

Electric Field ApplicationIn VivoRegulates Neural Precursor Cell Behavior in the Adult Mammalian Forebrain

“…Indeed, while the Wnt signaling pathway is important in promoting symmetric division of adult neural stem cells (Adachi et al, 2007;Piccin et al, 2011Piccin et al, , 2014Azim et al, 2014;Edri et al, 2015), we demonstrate that blocking the Wnt signaling pathway was not sufficient to abolish the increase in neurospheres seen with electrical stimulation compared with control. Our findings were consistent with electrical stimulation promoting stem cell survival (Du et al, 2018), with the potential to provide an effective approach to enhance neural regeneration. Interestingly, DBS has been used in clinical setting for many years to treat advanced stages of PD, despite a paucity of knowledge related to the functional substrates that lead to benefits.…”

Biomedical applications of electrical stimulation

“…The L-shaped EStim electrodes were attached to the lid of the 6-well plate, and were able to deliver uniform EStim to each individual well. In another study by Du et al [95], a 96-well plate-based high-throughput screening platform was developed for studying the optimal EStim parameters for human neural crest stem cell (NCSC) diferentiation. The EStim electrodes were arranged in a top-down coniguration to generate a vertical electrical ield that can stimulate a larger area.…”

“…The EStim therapy signiicantly improved the healing of rat femur large defects, with higher bone formation, strength and increased expression of osteogenic genes. The optimal EStim parameters identiied in the study by Du et al [95] was applied to NCSCs that were transplanted in live animals with sciatic nerve injuries. It was found that this EStim protocol signiicantly enhanced the survival rate and diferentiation of the transplanted NCSCs, as well as the overall nerve regeneration.…”

A study on graphene composites for peripheral nerve injury repair under electrical stimulation

“…[4][5][6] ES in neural crest stem cell (NCSC) transplantation signicantly enhanced nerve regeneration aer injury and repair. 7 Electrically pre-stimulating SCs (50 mV mm À1 ) promoted 30% more synapse outgrowth relative to co-stimulating both SCs with neurons, suggesting that ES modies SC phenotype. 8 Moreover, the better the development of the role of SCs through ES, the better would be the application in the repair of PNI.…”