Functional dopaminergic neurons derived from human chorionic mesenchymal stem cells ameliorate striatal atrophy and improve behavioral deficits in Parkinsonian rat model

Behavioral context improves optogenetic stimulation of transplanted dopaminergic cells in unilateral 6-OHDA rats

Stem cell therapy has long been a popular method of treatment for Parkinson's disease currently being researched in both preclinical and clinical settings. While early clinical results are based upon fetal tissue transplants rather than stem cell transplants, the lack of successful integration in some patients and gradual loss of effect in others suggests a more robust protocol is needed. We propose a two-front approach, one where transplants are directly stimulated in coordination with host activity elicited by behavioral tasks, which we refer to as behavioral context. After a pilot with unilateral 6-OHDA rats transplanted with dopaminergic cells differentiated from mesenchymal stem cells that were optogenetically stimulated during a swim task, we discovered that early stimulation predicted lasting reduction of motor deficits, even in the absence of later stimulation. This led to a follow-up with n = 21 rats split into three groups: one stimulated while performing a swim task (Stim-Swim; St-Sw), one not stimulated while swimming (NoStim-Swim; NSt-Sw), and one stimulated while stationary in a bowl (Stim-NoSwim; St-NSw). After initial stimulation (or lack thereof), all rats were retested two and seven days later with the swim task in the absence of stimulation. The St-Sw group gradually achieved and maintained symmetrical limb use, whereas the NSt-Sw group showed persistent asymmetry and the St-NSw group showed mixed results. This supports the notion that stem cell therapy should integrate targeted stimulation of the transplant with behavioral stimulation of the host tissue to encourage proper functional integration of the graft.

Caffeine modulates apoptosis, oxidative stress, and inflammation damage induced by tramadol in cerebellum of male rats

Tramadol, an opioid used as analgesic, can induce neurotoxic effects associated to cognitive dysfunction. Moreover, caffeine has been reported to have neuroprotective effects. In this regard, we hypothesized that administration of caffeine can modulate tramadol-induced damages in cerebellum. For this study, forty male Wistar rats were divided into four groups: the control group, the tramadol group (50mg/kg), the caffeine group (37.5mg/kg), and the tramadol+caffeine group (50mg/kg tramadol+37.5mg/kg caffeine). At the end of study (day 21), after performing rotarod behavioral test, cerebellum tissue samples were removed and prepared for further evaluations including biochemical profile markers (MDA, GPx, and SOD), immunohistochemistry for Caspase-3, as well as the expression of genes involved in cellular processes such as inflammation markers (IL-1β, HMGB1, IL-6, and TNF), apoptosis markers (Caspase-3, Caspase-8, Bax, and P21), and autophagy markers (LAMP2, ATG5, BECN1, and ATG12). Stereological evaluations were performed to determine the total volume of granular and molecular layers and white matter of cerebellum tissue and numerical density of the Purkinje cells. Our results showed that the stereological parameters, biochemical profiles (except MDA) and behavioral function were significantly higher in the tramadol+caffeine group compared to the tramadol group. Autophagy-related genes were significantly upregulated in tramadol+caffeine group compared to the tramadol group. While the expression of inflammatory and apoptosis genes, MDA level, as well as density of apoptosis cells were significantly lower in the tramadol+caffeine group compared to the tramadol group. Briefly, it can be concluded that administration of caffeine has neuroprotective effects in cerebellar damages induced by tramadol.

Autonomic behavioral impairment induced by simazine exposure during early life of male mouse is mediated by Lmx1a/Wnt1 pathway

Simazine is a widely used herbicide and known as an environmental estrogen. Multiple studies have proved simazine can induced the degeneration of dopaminergic neuron resulting in a degenerative disease-like syndrome. Herein, we explored the neurotoxicity of simazine on the dopaminergic nervous system of embryos and weaned offspring during the maternal gestation period or the maternal gestation and lactation periods. We found that simazine disturbed the crucial components expression involved in Lmx1a/Wnt1 pathway of dopaminergic neuron in embryonic and weaned offspring. Furthermore, morphological and behavioral tests performed on weaned male offspring treated by simazine suggested that the grip strength, autonomic exploring, and the space sense ability were weakened, as well as the pathological damage of dopaminergic neuron was clearly observed. But, the same neurotoxicity of simazine is less significantly observed in female offspring. Our findings will provide reliable reference for the determination of environmental limits and new insight into the pathogenesis of nonfamilial neurodegenerative diseases related to environmental risk factors.

Human olfactory epithelium-derived stem cells ameliorate histopathological deficits and improve behavioral functions in a rat model of cerebellar ataxia

Cell replacement therapy (CRT) is one of the most effective approaches used to alleviate symptoms of neurodegenerative syndromes such as cerebellar ataxia (CA). Human olfactory epithelium mesenchymal stem cells (OE-MSCs) have been recognized as a promising candidate for CRT, due to their distinctive features including immunomodulatory properties and ease of accessible compared to other types of MSCs. Hence, the main goal of our study was to explore the impacts of OE-MSCs transplantation on behavioral, structural, and histological deficiencies in a rat model of CA. After obtained an informed consent from volunteers, OE-MSCs were obtained from their nasal cavity. Then, OE-MSCs were characterized by the positive expression of CD73, CD90, and CD105 as MSCs as well as nestin and vimentin as primitive neuroectodermal stem cells markers. Then, the animals were randomized into three control, 3-acetylpyridine (3-AP) treated, and 3-AP + cell groups. In both experimental groups, the rats received intraperitoneal injection of 3-AP (75 mg/kg), followed by the implantation of OE-MSCs into the cerebellum of 3-AP + cell group. The impact of engrafted OE-MSCs on motor coordination and performance along with biochemical, immunohistochemical, and stereological changes in the cerebellum of the rat models of CA were investigated. According to our findings, the administration of 3-AP decreased the cerebellar GSH concentration. The injection of 3-AP also altered the morphological characteristics of the cerebellar Golgi cells. On the other hand, OE-MSCs transplantation improved motor coordination in CA. Besides, the implantation of OE-MSCs reduced caspase-3 expression and microglia proliferation in the cerebellum upon 3-AP administration. Finally, the transplant of OE-MSCs protected Purkinje cells against 3-AP toxicity. In sum, the present study revealed considerable advantages of OE-MSCs in managing CA animal model.

Neuroprotective effects of garlic extract on dopaminergic neurons of substantia nigra in a rat model of Parkinson's disease: motor and non-motor outcomes

Parkinson's disease (PD) is a common and severe neurodegenerative disorder associated with a selective loss of dopaminergic neurons in substantia nigra pars compacta. The crucial role of oxidative stress and inflammation in PD onset and progression is evident. It has been proven that garlic extract (GE) protects the cells from oxidative stress, inflammation, mitochondrial dysfunction and apoptosis. That is, we aimed to investigate if GE reveals protective features on the preclinical model of PD. The study has been designed to evaluate both preventive (GE administered before 6-OHDA injection) and therapeutic (GE administered after 6-OHDA injection) effects of GE on the animal model. Forty male Wistar rats were divided into 4 groups including control, lesion, treatment I (received GE before 6-OHDA injection) and treatment II (received GE both before and after 6-OHDA injection). At the end of treatment, hanging, rotarod, open field and passive avoidance tests as well as immunohistochemistry were performed to evaluate the neuroprotective effects of garlic against PD. Our immunohistochemistry analysis revealed that the tyrosine hydroxylase positive cells (TH⁺) in GE treated groups were significantly higher (p˂0.001) than the lesion group. The motor deficiency significantly improved in hanging, rotarod, open-field and apomorphine-induced rotational tests. We observed an attenuation in memory impairment induced by PD on GE treated group. Therefore, we found that GE protects dopaminergic neurons in 6-OHDA-induced neurotoxicity and ameliorates movement disorders and behavioral deficits.

Neural Basis of Dental Pulp Stem Cells and its Potential Application in Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. Though significant insights into the molecular-biochemical-cellular-behavioral basis of PD have been understood, there is no appreciable treatment available till date. Current therapies provide symptomatic relief without any influence on the progression of the disease. Stem cell therapy has been vigorously explored to treat PD. In this comprehensive review, we analyze various stem cell candidates for treating PD and discuss the possible mechanisms. We advocate the advantage of using neural crest originated dental pulp stem cells (DPSC) due to their predisposition towards neural differentiation and their potential to regenerate neurons far better than commonly used bone marrow derived mesenchymal stem cells (BM-MSCs). Eventually, we highlight the current challenges in the field and the strategies which may be used for overcoming the impediments.

Comparative study between bone marrow mesenchymal stem cell and their conditioned medium in the treatment of rat model of Parkinsonism

Parkinsonism is one of the most common aging neurodegenerative disorders. This study aims to compare the therapeutic effect of stem cell versus its conditioned medium in the Parkinsonism model. Parkinsonism was induced by daily subcutaneous injection of 0.5 mg/kg of rotenone dissolved in dimethyl sulfoxide for 28 days. Fifty rats were divided randomly into five groups: control, dimethyl sulfoxide, Parkinsonism, stem cell-treated, and conditioned medium-treated groups. Midbrain specimens were obtained for histological, immunohistochemical, and biochemical studies. Lewy bodies were observed in the Parkinsonism group in the dopaminergic neuron and neuropil as well. Almost all of the pathological changes were clearly ameliorated in both stem cell- and conditioned medium-treated groups as confirmed by biochemical, histological, and immunohistochemical (anti-nestin, anti-glial fibrillary acidic protein, and anti-α synuclein) studies. However, the conditioned medium showed more superior therapeutic effect establishing nearly the normal histological architecture of substantia nigra. These results may pave the future for using stem cell-conditioned medium as a more convenient and effective adjuvant therapy in Parkinsonism and other neurodegenerative disorders.