An Integrative Approach to Treat Parkinson's Disease: Ukgansan Complements L-Dopa by Ameliorating Dopaminergic Neuronal Damage and L-Dopa-Induced Dyskinesia in Mice

Effectiveness and safety of herbal medicine Ukgansan for clinical symptoms in Parkinson's disease: A pilot, randomized, assessor-blinded clinical trial

Objectives

Parkinson's disease (PD) is a neurodegenerative disease in which patients are suffering various symptoms. Previous experimental studies suggested that herbal medicine Ukgansan (UGS) could be beneficial for PD. The aim of this pilot clinical trial was to evaluate the efficacy of UGS for improving clinical symptoms in patients with PD.

Methods

Sixty patients with idiopathic PD were randomly assigned to receive either UGS plus acupuncture or acupuncture alone for 6 weeks. During the trial, all anti-parkinsonian medications were maintained. Subjects were evaluated for various clinical assessments of PD, including the Movement Disorder Society-Sponsored Revision of the Unified PD Rating Scale (MDS-UPDRS) and the 39-item Parkinson's Disease Questionnaire (PDQ-39), until 12 weeks.

Results

In MDS-UPDRS between the groups, no significant time x group interaction was found. In the subgroup analysis of participants with anxiety, a significant time x group interaction was found in the PDQ-39 domain of mobility (P = 0.007), activities of daily living (P = 0.042), and the PDQ-39 summary index (P = 0.048). In addition, post-hoc analysis in participants with anxiety showed a significant decrease in the domains of mobility (P = 0.001) and activities of daily living (P = 0.013) at week 7. There were no adverse events associated with UGS.

Conclusion

The additional administration of UGS has the potential to significantly improve the quality of life of PD patients with anxiety. In order to create more definitive evidence, clinical trials with more rigorous methodologies should be conducted in future.

Clinical trial registration

http://cris.nih.go.kr, identifier: KCT0003444.

Ukgansan Protects Dopaminergic Neurons against MPTP-Induced Neurotoxicity via the Nurr1 Signaling Pathway

Nuclear receptor-related 1 protein (Nurr1) is a nuclear hormone receptor that protects dopaminergic neurons and is a promising therapeutic target for Parkinson’s disease (PD). Parkinson’s disease is a neurodegenerative disorder caused by the destruction of dopaminergic neurons in the substantia nigra pars compacta (SNpc), and the long-term use of conventional dopamine replacement therapies causes many side effects, highlighting the need for new treatments such as complementary and alternative medicine. Ukgansan has been used in East Asia to treat neurological disorders, including neurodegenerative diseases, and has been reported to have strong effects in treating patients with PD. In addition, recent studies have reported that Ukgansan has a neuroprotective potential. However, there are no detailed studies on the mechanism of action of Nurr1. Thus, unlike previous studies, we focused on the Nurr1 pathways. We confirmed neurotoxicity and apoptosis signaling in the differentiated PC12 cells. In addition, to confirm the protective effect of Ukgansan, we conducted behavioral tests (motor coordination and postural balance, and bradykinesia) and tyrosine hydroxylase immunohistochemistry in both the SNpc and striatum. Specifically, this study demonstrated the effect of Ukgansan in protecting dopaminergic neurons and increasing Nurr1 involved in maintaining dopamine levels by activating Nurr1 expression in MPTP-induced PC12 cells and a mouse model of PD. In this mechanism, the loss of dopaminergic neurons and dopamine depletion were suppressed, and motor impairment caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity was improved. These results provide evidence that Ukgansan ameliorates PD’s motor symptoms and progression.

DA-9805, a Herbal Mixture, Restores Motor Manifestations in 6-Hydroxydopamine-induced Parkinson’s Disease Mouse Model by Regulating Striatal Dopamine and Acetylcholine Levels

Loss of dopamine (DA) is one of the primary features of Parkinson’s disease (PD); however, imbalances of non-dopaminergic neurotransmitters significantly contribute to the disabilities noted in advanced PD patients. DA-9805 is the ethanolic extraction of the root bark of Paeonia × suffruticosa Andrews (Paeoniaceae), the root of Angelica dahurica (Hoffm.) Benth. and Hook.f. ex Franch. and Sav. (Apiaceae) and the root of Bupleurum falcatum L. (Apiaceae), which have been widely utilized as an enhancer of motor function in East Asia. This study aimed to investigate whether DA-9805 modified motor dysfunctions and imbalances associated with DA and other neurotransmitters in a 6-hydroxydopamine-induced PD mouse. We confirmed the expressions of proteins related with neurotransmissions in the striatum. In addition, we measured the striatal neurotransmitters using HPLC and analyzed their correlation. DA-9805 significantly improved motor impairments and restored the altered levels of neurotransmitters in the striatum. Moreover, DA-9805 improved the altered expressions of tyrosine hydroxylase (TH), DA transporter, and choline acetyltransferase (ChAT) in the ipsilateral part of mouse striatum or SNpc, which implies the neuroprotection. We also found that the level of striatal acetylcholine (Ach) has the moderate negative correlation with motor functions and TH expression in the SNpc. This study indicates that DA-9805 restores motor dysfunctions by normalizing the increased levels of striatal Ach via modulating DA transmission and ChAT expressions as well as its neuroprotective effects.

Liposomal Form of L-Dopa and SH-Sy5y Cell-Derived Exosomes Modulate the Tyrosine Hydroxylase/Dopamine Receptor D2 Signaling Pathway in Parkinson's Rat Models

Parkinson's disease is a progressive neurodegenerative disorder in which dopaminergic neurons located in the substantia nigra are gradually lost. Currently, combined treatment strategies are receiving increasing attention as potential therapeutic approaches for Parkinson's disease. This study aimed to evaluate the potential effects of exosomes released from SH-Sy5y cells and the liposomal form of L-dopa on Parkinson's rat models. Twenty-five male Wistar albino rats, in five groups, were included in this study. Parkinson's disease was induced through microinjection of 6-OHDA (2.5 mg/mL) into the right substantia nigra. The exosomes released from the SH-Sy5y cell line were isolated and administered (0.2 µg/5 µL) alone or in combination with the liposomal form of L-Dopa (80 mg/kg) to the defined model groups. Behavioral tests and molecular assays were conducted to evaluate the expression levels of tyrosine hydroxylase (TH) and dopamine receptor D2 (DRD2). The rats in the groups receiving the combined liposomal form of L-Dopa and exosome treatment and the liposomal form of L-Dopa alone showed a significant improvement in their movement ability (p < 0.05). At molecular levels, these two groups also exhibited significant increases in Th (0.005 ± 0.001) and Drd2 (0.002 ± 0.0001) expression compared to controls (p < 0.05). The observed alterations of Th and Drd2 expression were not statistically significant in exosome- and L-Dopa-treated groups. The current study shows that exosome-derived neuronal cells and liposomal form of L-Dopa can protect different cells against pathological complications such as Parkinson's disease.

Interferon-γ Involvement in the Neuroinflammation Associated with Parkinson's Disease and L-DOPA-Induced Dyskinesia

Interferon-γ (IFN-γ) is a proinflammatory cytokine that activates glial cells. IFN-γ is increased in the plasma and brain of Parkinson's disease patients, suggesting its potential role in the disease. We investigated whether the IFN-γ deficiency could interfere with nigrostriatal degeneration induced by the neurotoxin 6-hydroxydopamine, L-DOPA-induced dyskinesia, and the neuroinflammatory features as astrogliosis, microgliosis, and induced nitric oxide synthase (iNOS) immunoreactivity induced by L-DOPA treatment. Wild type (WT) and IFN-γ knockout (IFN-γ/KO) mice received unilateral striatal microinjections of 6-hydroxydopamine. Animals were sacrificed 1, 3, 7, and 21 days after lesions. Additional group of WT and IFN-γ/KO parkinsonian mice, after 3 weeks of neurotoxin injection, received L-DOPA (intraperitoneally, for 21 days) resulting in dyskinetic-like behavior. Tyrosine hydroxylase immunostaining indicated the starting of dopaminergic lesion since the first day past toxin administration, progressively increased until the third day when it stabilized. There was no difference in the lesion and L-DOPA-induced dyskinesia intensity between WT and IFN-γ/KO mice. Remarkably, IFN-γ/KO mice treated with L-DOPA presented in the lesioned striatum an increase of iNOS and glial fibrilary acid protein (GFAP) density, compared with the WT group. Morphological analysis revealed the rise of astrocytes and microglia reactivity in IFN-γ/KO mice exibiting dyskinesia. In conclusion, IFN-γ/KO mice presented an intensification of the inflammatory reaction accompanying L-DOPA treatment and suggest that iNOS and GFAP increase, and the activation of astrocytes and microglia induced afterward L-DOPA treatment was IFN-γ independent events. Intriguingly, IFN-γ absence did not affect the degeneration of dopaminergic neurons or LID development.