Merav Bahat-Stromza

Protective Effects of Neurotrophic Factor–Secreting Cells in a 6-OHDA Rat Model of Parkinson Disease

Stem cell-based therapy is a promising treatment for neurodegenerative diseases. In our laboratory, a novel protocol has been developed to induce bone marrow-derived mesenchymal stem cells (MSC) into neurotrophic factors- secreting cells (NTF-SC), thus combining stem cell-based therapy with the NTF-based neuroprotection. These cells produce and secrete factors such as brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor. Conditioned medium of the NTF-SC that was applied to a neuroblastoma cell line (SH-SY5Y) 1 h before exposure to the neurotoxin 6-hydroxydopamine (6-OHDA) demonstrated marked protection. An efficacy study was conducted on the 6-OHDA-induced lesion, a rat model of Parkinsons disease. The cells, either MSC or NTF-SC, were transplanted on the day of 6-OHDA administration and amphetamine-induced rotations were measured as a primary behavior index. We demonstrated that when transplanted posterior to the 6-OHDA lesion, the NTF-SC ameliorated amphetamine-induced rotations by 45%. HPLC analysis demonstrated that 6-OHDA induced dopamine depletion to a level of 21% compared to the untreated striatum. NTF-SC inhibited dopamine depletion to a level of 72% of the contralateral striatum. Moreover, an MRI study conducted with iron-labeled cells, followed by histological verification, revealed that the engrafted cells migrated toward the lesion. In a histological assessment, we found that the cells induced regeneration in the damaged striatal dopaminergic nerve terminal network. We therefore conclude that the induced MSC have a therapeutic potential for neurodegenerative processes and diseases, both by the NTFs secretion and by the migratory trait toward the diseased tissue.

Migration of Neurotrophic Factors‐Secreting Mesenchymal Stem Cells Toward a Quinolinic Acid Lesion as Viewed by Magnetic Resonance Imaging

Stem cell‐based treatment is a promising frontier for neurodegenerative diseases. We propose a novel protocol for inducing the differentiation of rat mesenchymal stem cells (MSCs) toward neurotrophic factor (NTF)‐secreting cells as a possible neuroprotective agent. One of the major caveats of stem cell transplantation is their fate post‐transplantation. To test the viability of the cells, we tracked the transplanted cells in vivo by magnetic resonance imaging (MRI) scans and validated the results by histology. MSCs went through a two‐step medium‐based differentiation protocol, followed by in vitro characterization using immunocytochemistry and immunoblotting analysis of the cell media. We examined the migratory properties of the cells in the quinolinic acid (QA)‐induced striatal lesion model for Huntingtons disease. The induced cells were labeled and transplanted posterior to the lesion. Rats underwent serial MRI scans to detect cell migration in vivo. On the 19th day, animals were sacrificed, and their brains were removed for immunostaining. Rat MSCs postinduction exhibited both neuronal and astrocyte markers, as well as production and secretion of NTFs. High‐resolution two‐dimensional and three‐dimensional magnetic resonance images revealed that the cells migrated along a distinct route toward the lesion. The in vivo MRI results were validated by the histological study, which demonstrated that phagocytosis had only partially occurred and that MRI could correctly depict the status of the migrating cells. The results show that these cells migrated toward a QA lesion and therefore survived for 19 days post‐transplantation. This gives hope for future research harnessing these cells for treating neurodegenerative diseases.

A novel brain-targeted antioxidant (AD4) attenuates haloperidol-induced abnormal movement in rats: implications for tardive dyskinesia.

Background:Tardive dyskinesia (TD), characterized by abnormal movements, is the major late-onset chronic side effect of antipsychotic treatment found in about 30% of those patients. The association of oxidative stress and the release of free radicals is one of the hallmarks of dopaminergic malfunctions and is one of the leading theories suggested for the pathophysiology of TD. To this day, no brain-targeted antioxidant has been tested as a potential treatment of TD. In light of this assumption, the authors chose a novel, low-molecular weight thiol antioxidant, N-acetyl cysteine amide (AD4), that crosses the blood-brain barrier as a possible treatment of TD. Objective:To examine the protective effects of the novel brain-penetrating antioxidant AD4 on TD experimental models. Methods:The typical vacuous chewing movement occurs in rats following chronic haloperidol injections (1.5 mg/kg/day intraperitoneally for 21 days). This purposeless mouth opening in the vertical plane is similar to TD symptoms in humans. The authors tested rats treated with haloperidol without or with AD4 in the drinking water (1 g/kg orally). Thiobarbituric acid reactive substances and anticarbonyl antibodies were used to measure oxidation of membranes and proteins. Results:Haloperidol increased the vacuous chewing movements to 66.5 ± 7.6 movements/5 minutes compared with 16.4 ± 2.4 movements/5 minutes in untreated rats (P < 0.01). Coadministration of haloperidol and AD4 decreased the vacuous chewing movements level to 42.1 ± 6.7 movements/5 minutes (P < 0.05). Haloperidol also increased the level of lipid peroxidation and protein oxidation in the rat brain, whereas coadministration with AD4 preserved their normal levels. Conclusion:Haloperidol causes behavioral abnormalities associated with oxidative stress in rats, similar to TD. AD4, the brain-targeted potent antioxidant, reduces the cellular oxidation markers and improves the typical clinical behavior. Hence, AD4 is a potential new treatment of antipsychotic-induced TD.