Compound Formula Rehmannia alleviates levodopa-induced dyskinesia in Parkinson's disease

Current Knowledge on the Background, Pathophysiology and Treatment of Levodopa-Induced Dyskinesia-Literature Review

Levodopa remains the primary drug for controlling motor symptoms in Parkinson’s disease through the whole course, but over time, complications develop in the form of dyskinesias, which gradually become more frequent and severe. These abnormal, involuntary, hyperkinetic movements are mainly characteristic of the ON phase and are triggered by excess exogenous levodopa. They may also occur during the OFF phase, or in both phases. Over the past 10 years, the issue of levodopa-induced dyskinesia has been the subject of research into both the substrate of this pathology and potential remedial strategies. The purpose of the present study was to review the results of recent research on the background and treatment of dyskinesia. To this end, databases were reviewed using a search strategy that included both relevant keywords related to the topic and appropriate filters to limit results to English language literature published since 2010. Based on the selected papers, the current state of knowledge on the morphological, functional, genetic and clinical features of levodopa-induced dyskinesia, as well as pharmacological, genetic treatment and other therapies such as deep brain stimulation, are described.

Protective Effect of Compound Formula Rehmannia against Neurotoxicity and Apoptosis Induced by α-Syn in In Vivo and In Vitro Models of Parkinson's Disease

The present study aimed to investigate the protective effect of compound formula Rehmannia (CFR) against the development of Parkinson's disease (PD). After the in vivo and in vitro models of PD were established with overexpression α-syn induced, CFR was administrated into the PD model rats for 6 weeks or SK-N-SH cells with coincubation for 48 h. Apomorphine-induced rotation test, CCK8 assay, TUNEL assay, immunofluorescence staining, and western blot assay were performed to evaluate the behavioral changes, cell viability, cell apoptosis, α-syn, GSK-3β, P-GSK-3β (Ser9), P-GSK-3β (Tyr216), and β-catenin expression in PD rats or SK-N-SH cells. PD rat behavior results showed that the rotation numbers were significantly decreased in the CFR treatment group comparing with the AAV-α-syn PD model group. The cell viability suppressed by H₂O₂ and α-syn in SK-N-SH model cells was also significantly improved with CFR administration. Cell apoptosis and α-syn overexpression observed in PD rats and SK-N-SH cells were also inhibited by CFR treatment. Furthermore, the protein expression of α-syn, GSK-3β, P-GSK-3β (Ser9), P-GSK-3β (Tyr216), and β-catenin in in vivo and in vitro was also significantly regulated by CFR. The present study suggested that CFR may be considered as a potential neuroprotective agent against PD, and this application will require further investigation.

Dried Rehmannia root protects against glutamate-induced cytotoxity to PC12 cells through energy metabolism-related pathways

Rehmannia has been shown to be clinically effective in treating neurodegenerative diseases; however, the neuroprotective mechanisms remain unclear. In this study, we established a model of neurodegenerative disease using PC12 cytotoxic injury induced by glutamate. The cells were treated with 20 mM glutamate in the absence or presence of water extracts of dried Rehmannia root of varying concentrations (70%, 50% and 30%). The different concentrations of Rehmannia water extract significantly increased the activity of glutamate-injured cells, reduced the release of lactate dehydrogenase, inhibited apoptosis, increased the concentrations of NADH, NAD and ATP in cells, ameliorated mitochondrial membrane potential, and reduced the levels of light chain 3. Taken together, our findings demonstrate that Rehmannia water extracts exert a cytoprotective effect against glutamate-induced PC12 cell injury via energy metabolism-related pathways.

Palmitoyl Serotonin Inhibits L-dopa-induced Abnormal Involuntary Movements in the Mouse Parkinson Model

L-3,4-dihydroxyphenylalanine (L-DOPA) is the most common treatment for patients with Parkinson's disease (PD). However, long term use of L-DOPA for PD therapy lead to abnormal involuntary movements (AIMs) known as dyskinesia. Fatty acid amide hydrolase (FAAH) is enriched protein in basal ganglia, and inhibition of the protein reduces dyskinetic behavior of mice. Palmitoyl serotonin (PA-5HT) is a hybrid molecule patterned after arachidonoyl serotonin, antagonist of FAAH. However, the effect of PA-5HT on L-DOPA-induced dyskinesia (LID) in PD have not yet been elucidated. To investigate whether PA-5HT relieve LID in PD and decrease hyperactivation of dopamine D1 receptors, we used the 6-hydroxydopomine (6-OHDA)-lesioned mouse model of PD and treated the L-DOPA (20 mg/kg) for 10 days with PA-5HT (0.3 mg/kg/day). The number of wall contacts with the forelimb in the cylinder test was significantly decreased by 6-OHDA lesion in mice and the pharmacotherapeutic effect of L-DOPA was also revealed in PA-5HT-treated mice. Moreover, in AIMs test, PA-5HT-treated mice showed significant reduction of locomotive, axial, limb, and orofacial AIMs score compared to the vehicle-treated mice. LID-induced hyper-phosphorylation of ERK1/2 and overexpression of FosB/ΔFosB was markedly decreased in 6-OHDA-lesioned striatum of PA-5HT-treated mice, indicating that PA-5HT decreased the dopamine D1 receptor-hyperactivation induced by chronic treatment of L-DOPA in dopamine-denervated striatum. These results suggest that PA-5HT effectively attenuates the development of LID and enhance of ERK1/2 phosphorylation and FosB/ΔFosB expression in the hemi-parkinsonian mouse model. PA-5HT may have beneficial effect on the LID in PD.

A novel method for evaluating brain function and microstructural changes in Parkinson's disease

In this study, microstructural brain damage in Parkinson's disease patients was examined using diffusion tensor imaging and tract-based spatial statistics. The analyses revealed the presence of neuronal damage in the substantia nigra and putamen in the Parkinson's disease patients. Moreover, disease symptoms worsened with increasing damage to the substantia nigra, confirming that the substantia nigra and basal ganglia are the main structures affected in Parkinson's disease. We also found that microstructural damage to the putamen, caudate nucleus and frontal lobe positively correlated with depression. Based on the tract-based spatial statistics, various white matter tracts appeared to have microstructural damage, and this correlated with cognitive disorder and depression. Taken together, our results suggest that diffusion tensor imaging and tract-based spatial statistics can be used to effectively study brain function and microstructural changes in patients with Parkinson's disease. Our novel findings should contribute to our understanding of the histopathological basis of cognitive dysfunction and depression in Parkinson's disease.

An Oriental Medicine, Hyungbangpaedok-San Attenuates Motor Paralysis in an Experimental Model of Multiple Sclerosis by Regulating the T Cell Response

The preventive and therapeutic mechanisms in multiple sclerosis are not clearly understood. We investigated whether Hyungbangpaedok-san (HBPDS), a traditional herbal medicine, has a beneficial effect in experimental autoimmune encephalomyelitis (EAE) mice immunized with myelin oligodendrocyte glycoprotein peptide (MOG_35-55). Onset-treatment with 4 types of HBPDS (extracted using distilled water and 30%/70%/100% ethanol as the solvent) alleviated neurological signs, and HBPDS extracted within 30% ethanol (henceforth called HBPDS) was more effective. Onset-treatment with HBPDS reduced demyelination and the recruitment/infiltration and activation of microglia/macrophages in the spinal cord of EAE mice, which corresponded to the reduced mRNA expression of pro-inflammatory cytokines (TNF-α, IL–6, and IL–1β), iNOS, and chemokines (MCP–1, MIP–1α, and RANTES) in the spinal cord. Onset-treatment with HBPDS inhibited changes in the components of the blood-brain barrier such as astrocytes, adhesion molecules (ICAM–1 and VCAM–1), and junctional molecules (claudin–3, claudin–5, and zona occludens–1) in the spinal cord of EAE mice. Onset-treatment with HBPDS reduced the elevated population of CD4⁺, CD4⁺/IFN-γ⁺, and CD4⁺/IL–17⁺ T cells in the spinal cord of EAE mice but it further increased the elevated population of CD4⁺/CD25⁺/Foxp3⁺ and CD4⁺/Foxp3⁺/Helios⁺ T cells. Pre-, onset-, post-, but not peak-treatment, with HBPDS had a beneficial effect on behavioral impairment in EAE mice. Taken together, HBPDS could alleviate the development/progression of EAE by regulating the recruitment/infiltration and activation of microglia and peripheral immune cells (macrophages, Th1, Th17, and Treg cells) in the spinal cord. These findings could help to develop protective strategies using HBPDS in the treatment of autoimmune disorders including multiple sclerosis.