In this study, we aim to demonstrate the fate of allogenic adult human olfactory bulb neural stem/progenitor cells (OBNSC/NPCs) transplanted into the rat hippocampus treated with ibotenic acid (IBO), a neurotoxicant specific to hippocampal cholinergic neurons that are lost in Alzheimer's disease. We assessed their possible ability to survive, integrate, proliferate, and differentiate into different neuronal and glial elements: we also evaluate their possible therapeutic potential, and the mechanism(s) relevant to neuroprotection following their engraftment into the CNS milieu. OBNSC/NPCs were isolated from adult human olfactory bulb patients, genetically engineered to express GFP and human nerve growth factor (hNGF) by lentivirus-mediated infection, and stereotaxically transplanted into the hippocampus of IBO-treated animals and controls. Stereological analysis of engrafted OBNSCs eight weeks post transplantation revealed a 1.89 fold increase with respect to the initial cell population, indicating a marked ability for survival and proliferation. In addition, 54.71 ± 11.38%, 30.18 ± 6.00%, and 15.09 ± 5.38% of engrafted OBNSCs were identified by morphological criteria suggestive of mature neurons, oligodendrocytes and astrocytes respectively. Taken together, this work demonstrated that human OBNSCs expressing NGF ameliorate the cognitive deficiencies associated with IBO-induced lesions in AD model rats, and the improvement can probably be attributed primarily to neuronal and glial cell replacement as well as the trophic influence exerted by the secreted NGF.
Parkinson's disease (PD) is a neurological disorder characterized by the loss of midbrain dopaminergic (DA) neurons. Neural stem cells (NSCs) are multipotent stem cells that are capable of differentiating into different neuronal and glial elements. The production of DA neurons from NSCs could potentially alleviate behavioral deficits in Parkinsonian patients; timely intervention with NSCs might provide a therapeutic strategy for PD. We have isolated and generated highly enriched cultures of neural stem/progenitor cells from the human olfactory bulb (OB). If NSCs can be obtained from OB, it would alleviate ethical concerns associated with the use of embryonic tissue, and provide an easily accessible cell source that would preclude the need for invasive brain surgery. Following isolation and culture, olfactory bulb neural stem cells (OBNSCs) were genetically engineered to express hNGF and GFP. The hNFG-GFP-OBNSCs were transplanted into the striatum of 6-hydroxydopamin (6-OHDA) Parkinsonian rats. The grafted cells survived in the lesion environment for more than eight weeks after implantation with no tumor formation. The grafted cells differentiated in vivo into oligodendrocyte-like (25 ± 2.88%), neuron-like (52.63 ± 4.16%), and astrocyte -like (22.36 ± 1.56%) lineages, which we differentiated based on morphological and immunohistochemical criteria. Transplanted rats exhibited a significant partial correction in stepping and placing in non-pharmacological behavioral tests, pole and rotarod tests. Taken together, our data encourage further investigations of the possible use of OBNSCs as a promising cell-based therapeutic strategy for Parkinson's disease.
In the current study, we aimed to investigate the neurotoxic effect of oral titanium dioxide nanoparticles (TiO2 NPs) as well as the possible neuroprotective effect of carboxymethyl chitosan in adult rats for 14 days. The results revealed that TiO2 NPs inhibited the activity of the acetylcholine esterase enzyme and the levels of serotonin, dopamine, and norepinephrine neurotransmitters. Additionally, it induced neuro‐oxidative stress and neuroinflammation via an elevation in MDA levels and IL‐6, while GSH concentration, as well as GPx and GST activities, were decreased. TiO2 NPs induced neuronal apoptosis through upregulation of the expression of caspase‐8 and ‐9 that was further confirmed by increasing caspases‐3 and ‐8 proteins in the hippocampus, cerebral cortex, and cerebellum. The expression of the immediate‐early gene BDNF was increased in response to TiO2 NPs, while that of Arc was reduced. Chitosan significantly attenuated the TiO2 NPs‐induced neurotoxicity regarding AChE, serotonin, MDA, GSH, GPx, GST, IL‐6, caspases‐8, ‐9, and ‐3. Chitosan inhibited the expression of Arc and alleviated the effect of TiO2 NPs on BDNF expression. Collectively, TiO2 NPs induced neurotoxicity via their action on vital neuronal biomarkers that might in turn cause brain dysfunction. Despite the neuroprotection of chitosan, its inhibitory effect on Arc expression should be considered.
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