Harnessing the stem cell potential: a case for neural stem cell therapy

Microfluidic electrode array chip for electrical stimulation-mediated axonal regeneration

The precise manipulation of the neural stem cell (NSC)-derived neural differentiation is still challenging, and there is a technological barrier to regulate the axonal regeneration in a controlled manner. Here, we developed a microfluidic chip integrated with a microelectrode array as an axonal guidance platform. The microfluidic electrode array chip consisted of two compartments and a bridge microchannel that could isolate and guide the axons. We demonstrated that the NSCs were largely differentiated into neural cells as the electric field was applied to the microfluidic electrode array chip. We also confirmed the synergistic effects of the electrical stimulation (ES) and neurotrophic factor (NF) on axonal outgrowth. This microfluidic electrode array chip can serve as a central nervous system (CNS) model for axonal injury and regeneration. Therefore, it could be a potentially powerful tool for an in vitro model of the axonal regeneration.

Enhanced neural stem cell functions in conductive annealed carbon nanofibrous scaffolds with electrical stimulation

Carbon-based nanomaterials have shown great promise in regenerative medicine because of their unique electrical, mechanical, and biological properties; however, it is still difficult to engineer 2D pure carbon nanomaterials into a 3D scaffold while maintaining its structural integrity. In the present study, we developed novel carbon nanofibrous scaffolds by annealing electrospun mats at elevated temperature. The resultant scaffold showed a cohesive structure and excellent mechanical flexibility. The graphitic structure generated by annealing renders superior electrical conductivity to the carbon nanofibrous scaffold. By integrating the conductive scaffold with biphasic electrical stimulation, neural stem cell proliferation was promoted associating with upregulated neuronal gene expression level and increased microtubule-associated protein 2 immunofluorescence, demonstrating an improved neuronal differentiation and maturation. The findings suggest that the integration of the conducting carbon nanofibrous scaffold and electrical stimulation may pave a new avenue for neural tissue regeneration.

Transdifferentiation-Induced Neural Stem Cells Promote Recovery of Middle Cerebral Artery Stroke Rats

Induced neural stem cells (iNSCs) can be directly transdifferentiated from somatic cells. One potential clinical application of the iNSCs is for nerve regeneration. However, it is unknown whether iNSCs function in disease models. We produced transdifferentiated iNSCs by conditional overexpressing Oct4, Sox2, Klf4, c-Mycin mouse embryonic fibroblasts. They expanded readily in vitro and expressed NSC mRNA profile and protein markers. These iNSCs differentiated into mature astrocytes, neurons and oligodendrocytes in vitro. Importantly, they reduced lesion size, promoted the recovery of motor and sensory function as well as metabolism status in middle cerebral artery stroke rats. These iNSCs secreted nerve growth factors, which was associated with observed protection of neurons from apoptosis. Furthermore, iNSCs migrated to and passed through the lesion in the cerebral cortex, where Tuj1+ neurons were detected. These findings have revealed the function of transdifferentiated iNSCs in vivo, and thus provide experimental evidence to support the development of personalized regenerative therapy for CNS diseases by using genetically engineered autologous somatic cells.

Concise Review: Prospects of Bone Marrow Mononuclear Cells and Mesenchymal Stem Cells for Treating Status Epilepticus and Chronic Epilepsy

Mononuclear cells (MNCs) and mesenchymal stem cells (MSCs) derived from the bone marrow and other sources have received significant attention as donor cells for treating various neurological disorders due to their robust neuroprotective and anti-inflammatory effects. Moreover, it is relatively easy to procure these cells from both autogenic and allogenic sources. Currently, there is considerable interest in examining the usefulness of these cells for conditions such as status epilepticus (SE) and chronic epilepsy. A prolonged seizure activity in SE triggers neurodegeneration in the limbic brain areas, which elicits epileptogenesis and evolves into a chronic epileptic state. Because of their potential for providing neuroprotection, diminishing inflammation and curbing epileptogenesis, early intervention with MNCs or MSCs appears attractive for treating SE as such effects may restrain the development of chronic epilepsy typified by spontaneous seizures and learning and memory impairments. Delayed administration of these cells after SE may also be useful for easing spontaneous seizures and cognitive dysfunction in chronic epilepsy. This concise review evaluates the current knowledge and outlook pertaining to MNC and MSC therapies for SE and chronic epilepsy. In the first section, the behavior of these cells in animal models of SE and their efficacy to restrain neurodegeneration, inflammation, and epileptogenesis are discussed. The competence of these cells for suppressing seizures and improving cognitive function in chronic epilepsy are conferred in the next section. The final segment ponders issues that need to be addressed to pave the way for clinical application of these cells for SE and chronic epilepsy.

Translation of Cell Therapies to the Clinic: Characteristics of Cell Suspensions in Large-Diameter Injection Cannulae

With the use of cell replacement therapies as a realistic prospect for conditions such as Parkinson's and Huntington's diseases, the logistics of the delivery of cell suspensions to deep brain targets is a topic for consideration. Because of the large cannulae required for such procedures, we need to consider the behavior of cell suspensions within the cannulae if we are to ensure that the injected cells are distributed as intended within the target tissue. We have investigated the behavior of primary embryonic cell suspensions of neural tissue, in cannulae of different diameters, using a protocol designed to mimic the handling and injection of cells during clinical application. Internal cannula diameter had a large effect on the distribution of cells during their dispensation from the syringe. In vertical or near vertical cannulae, cells settled toward the tip of the needle, and were dispensed unevenly, with the majority of cells emerging in the first 10-20% of the injectate. In horizontal or near-horizontal cannulae, we observed the opposite effect, such that few cells were dispensed in the first 80% of the injectate, and the majority emerged in the final 10-20%. Use of a glass cannula showed that the results obtained using the horizontal cannula were caused by settling and adherence of the cells on the side of the cannulae, such that during dispensation, the overlying, cell-free solution was dispensed first, prior to the emergence of the cells. We show that the behavior of cells in such cannulae is affected by the cannula diameter, and by the material of the cannula itself. In horizontal cannulae, uneven expulsion of cells from the needle can be ameliorated by regular rotation of the cannula during the procedure. We discuss the potential impact of these observations on the translation of cell therapies to the clinic.

Adult neurogenesis: mechanisms and functional significance

New neurons are generated throughout life in distinct regions of the mammalian brain. This process, called adult neurogenesis, has been implicated in physiological brain function, and failing or altered neurogenesis has been associated with a number of neuropsychiatric diseases. Here, we provide an overview of the mechanisms governing the neurogenic process in the adult brain and describe how new neurons may contribute to brain function in health and disease.