Rasagiline: a guide to its use in Parkinson's disease

Kai-xin-san improves cognitive impairment in D-gal and Aβ25-35 induced ad rats by regulating gut microbiota and reducing neuronal damage

ETHNOPHARMACOLOGICAL RELEVANCE

Kai-Xin-San (KXS) is a classic herbal formula for the treatment and prevention of AD (Alzheimer's disease) with definite curative effect, but its mechanism, which involves multiple components, pathways, and targets, is not yet fully understood.

AIM OF THE STUDY

To verify the effect of KXS on gut microbiota and explore its anti-AD mechanism related with gut microbiota.

MATERIALS AND METHODS

AD rat model was established and evaluated by intraperitoneal injection of D-gal and bilateral hippocampal CA1 injections of Aβ25-35. The pharmacodynamics of KXS in vivo includes general behavior, Morris water maze test, ELISA, Nissl & HE staining and immunofluorescence. Systematic analysis of gut microbiota was conducted using 16S rRNA gene sequencing technology. The potential role of gut microbiota in the anti-AD effect of KXS was validated with fecal microbiota transplantation (FMT) experiments.

RESULTS

KXS could significantly improve cognitive impairment, reduce neuronal damage and attenuate neuroinflammation and colonic inflammation in vivo in AD model rats. Nine differential intestinal bacteria associated with AD were screened, in which four bacteria (Lactobacillus murinus, Ligilactobacillus, Alloprevotella, Prevotellaceae_NK3B31_group) were very significant.

CONCLUSION

KXS can maintain the ecological balance of intestinal microbiota and exert its anti-AD effect by regulating the composition and proportion of gut microbiota in AD rats through the microbiota-gut-brain axis.

Comparison of selegiline and levodopa combination therapy versus levodopa monotherapy in the treatment of Parkinson's disease: a meta-analysis

BACKGROUND

Selegiline or levodopa treatment has been suggested as a therapeutic method for Parkinson's disease (PD) in many clinical trial reports. However, the combined effects of two drugs still remain controversial. The aim of this report was to evaluate the clinical efficacy and safety of selegiline plus levodopa (S + L) combination therapy in the treatment of PD compared to that of L monotherapy, to provide a reference resource for rational drug use.

METHODS

Randomized controlled trials (RCTs) of S + L for PD published up to September, 2018 were searched. Mean difference (MD), odds ratio (OR), and 95% confidence interval (CI) were calculated and heterogeneity was assessed with the I² test. Sensitivity analysis was also performed. The outcomes measured were as follows: the unified Parkinson's disease rating scale (UPDRS) scores, modified Webster score, adverse events and mortality.

RESULTS

Fourteen RCTs with 2008 participants were included. Compared with L monotherapy, the pooled effects of S + L combination therapy on UPDRS score were (eleven trials; MD - 7.00, 95% CI - 8.35 to - 5.65, P < 0.00001) for total UPDRS score (nine trials; MD - 5.74, 95% CI - 7.71 to - 3.77, P < 0.00001) for motor UPDRS score (seven trials; MD - 1.61, 95% CI - 2.18 to - 1.04, P < 0.00001) for activities of daily living UPDRS score (three trials; MD - 0.38, 95% CI - 0.61 to - 0.14, P = 0.002) for mental UPDRS score. The Webster score showed significant decrease in the S + L combination therapy compared to L monotherapy (four trials; MD - 5.71, 95% CI - 7.11 to - 4.32, P < 0.00001). Compared with L monotherapy, S + L combination therapy did not increase the number of any adverse events significantly in PD patients (ten trials; OR 1.58, 95% CI 0.83-3.00, P = 0.16).

CONCLUSIONS

S + L combination therapy is superior to L monotherapy for the improvement of clinical symptoms in PD patients. Moreover, the safety profile of S + L combination therapy is comparable with that of L monotherapy.

Target Molecular-Based Neuroactivity Screening and Analysis of Panax ginseng by Affinity Ultrafiltration, UPLC-QTOF-MS and Molecular Docking

Panax ginseng exerts good neuroprotective activity at the cell and animal level, but the specific bioactive compounds and action mechanism are needed to be investigated, verified, and confirmed. In this work, affinity ultrafiltration (AUF), UPLC-QTOF-MS, and molecular docking were integrated into one strategy to screen, identify, and evaluate the bioactive compounds in ginseng at the molecular level. Three biological macromolecules (AChE, MAO-B, and NMDA receptor) were selected as the target protein for AUF-MS screening for the first time, and 16 potential neuroactive compounds were found with suitable binding degree. Then, the bioactivity of ginseng and its components were evaluated by AChE-inhibitory test and DPPH assay, and the data indicate that ginseng extract and the screened compounds have good neuroactivity. The interaction between the three targets and the screened compounds was further analyzed by molecular docking, and the results were consistent with a few discrepancies in comparison with the AUF results. Finally, according to the corresponding relation between component-target-pathway, the action mechanism of ginseng elucidated that ginseng exerts a therapeutic effect on AD through multiple relations of components, targets, and pathways, which is in good accordance with the TCM theory.

Drug therapy for Parkinson’s disease: An update

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder, affecting about 1% of the population above the age of 65. PD is characterized by a selective degeneration of the dopaminergic neurons of the substantia nigra pars compacta. This results in a marked loss of striatal dopamine and the development of the characteristic features of the disease, i.e., bradykinesia, rest tremor, rigidity, gait abnormalities and postural instability. Other types of neurons/neurotransmitters are also involved in PD, including cholinergic, serotonergic, glutamatergic, adenosine, and GABAergic neurotransmission which might have relevance to the motor, non-motor, neuropsychiatric and cognitive disturbances that occur in the course of the disease. The treatment of PD relies on replacement therapy with levodopa (L-dopa), the precursor of dopamine, in combination with a peripheral decarboxylase inhibitor (carbidopa or benserazide). The effect of L-dopa, however, declines over time together with the development of motor complications especially dyskinesia in a significant proportion of patients within 5 years of therapy. Other drugs include dopamine-receptor-agonists, catechol-O-methyltransferase inhibitors, monoamine oxidase type B (MAO-B) inhibitors, anticholinergics and adjuvant therapy with the antiviral drug and the N-methyl-D-aspartate glutamate receptor antagonist amantadine. Although, these medications can result in substantial improvements in parkinsonian symptoms, especially during the early stages of the disease, they are often not successful in advanced disease. Moreover, dopaminergic cell death continues over time, emphasizing the need for neuroprotective or neuroregenerative therapies. In recent years, research has focused on non-dopaminergic approach such as the use of A_2A receptor antagonists: istradefylline and preladenant or the calcium channel antagonist isradipine. Safinamide is a selective and reversible inhibitor of MAO-B, a glutamate receptor inhibitor as well as sodium and calcium channel blocker. Minocycline and pioglitazone are other agents which have been shown to prevent dopaminergic nigral cell loss in animal models of PD. There is also an evidence to suggest a benefit from iron chelation therapy with deferiprone and from the use of antioxidants or mitochondrial function enhancers such as creatine, alpha-lipoic acid, l-carnitine, and coenzyme Q10.