Harvested human neurons engineered as live nervous tissue constructs: implications for transplantation

Abstract

Object-Although neuron transplantation to repair the nervous system has shown promise in animal models, there are few practical sources of viable neurons for clinical application and insufficient approaches to bridge extensive nerve damage in patients. Therefore, the authors sought a clinically relevant source of neurons that could be engineered into transplantable nervous tissue constructs. The authors chose to evaluate human dorsal root ganglion (DRG) neurons due to their robustness in culture.Methods-Cervical DRGs were harvested from 16 live patients following elective ganglionectomies, and thoracic DRGs were harvested from 4 organ donor patients. Following harvest, the DRGs were digested in a dispase-collagenase treatment to dissociate neurons for culture. In addition, dissociated human DRG neurons were placed in a specially designed axon expansion chamber that induces continuous mechanical tension on axon fascicles spanning 2 populations of neurons originally plated ~ 100 μm apart.Results-The adult human DRG neurons, positively identified by neuronal markers, survived at least 3 months in culture while maintaining the ability to generate action potentials. Stretchgrowth of axon fascicles in the expansion chamber occurred at the rate of 1 mm/day to a length of 1 cm, creating the first engineered living human nervous tissue constructs.Conclusions-These data demonstrate the promise of adult human DRG neurons as an alternative transplant material due to their availability, viability, and capacity to be engineered. Also, these data show the feasibility of harvesting DRGs from living patients as a source of neurons for autologous transplant as well as from organ donors to serve as an allograft source of neurons.

Long-Term Survival and Integration of Transplanted Engineered Nervous Tissue Constructs Promotes Peripheral Nerve Regeneration

“…31 Neurons for these human nervous tissue constructs were harvested from both living patients undergoing therapeutic ganglionectomies and from organ donors, demonstrating the feasibility of creating either autologous or allogeneic grafts. Notably, the survival of the allogeneic transplants in the present animal study bodes well for clinical application using either cell source.…”

Stretch growth of integrated axon tracts: Extremes and exploitations

“…Regardless, their robustness to be removed from culture provides a unique opportunity to develop transplantable nervous tissue constructs to repair even extensive nervous system damage. With a geometry almost like a ‘mini-nervous system,’ stretch grown cultures appear to have the capacity to integrate with host nervous tissue at both sides of a lesion, creating a living bridge (Huang et al, 2006, 2008, 2009; Iwata et al, 2006; Pfister et al, 2004, 2006a,b). …”

“…To demonstrate the clinical feasibility of using axon stretch growth to repair the nervous system, adult human DRG neurons have also been engineered into nervous tissue constructs (Huang et al, 2008). Harvested adult human DRG neurons have been isolated from patients undergoing elective ganglionectomies and from organ donors.…”

Carboxylated graphene oxide promoted axonal guidance growth by activating Netrin‐1/deleted in colorectal cancer signaling in rat primary cultured cortical neurons

“…Our previous study demonstrated that nanomaterials can promote neuronal guidance and growth mediated by Netrin‐1/DCC signaling pathway, so here we hypothesized that graphene can stimulate axonal guidance and growth and supplement neuronal electrical physiology during neuronal synapses formation. Netrin‐1 as an axon guidance cue plays an important role in the development and regeneration of the central nervous system, and axonal outgrowth is critical for neurons to establish their circuitry . But the effect of GO and GO‐COOH on such axonal guidance needs to be clarified.…”