The Management of Parkinson's Disease: An Overview of the Current Advancements in Drug Delivery Systems

Revealing the therapeutic targets, mechanisms, and heterogeneity of Huatan Jieyu Granules for Parkinson's disease through single-cell sequencing

BACKGROUND

The incidence of Parkinson's disease (PD) increases with age. Previous pharmacological studies have shown the potential of Huatan Jieyu Granules (HGs) for the treatment of PD, but the exact mechanisms remain unclear. This study aimed to explore the effects of herbal treatment on PD using mouse models and single-cell sequencing.

METHODS

In this study, we established in vivo 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD models in mice. Motor function was assessed through behavioral tests. Immunofluorescence was used to examine dopaminergic neuron loss. Single-cell sequencing was performed on mice from the blank, PD model and medication groups. After quality control and dimensionality reduction of the single-cell data, cells were clustered, and different cell types were identified. We then identified the intersection of differentially expressed genes (DEGs1) in the blank and model groups and DEGs2 in the model and medication groups, yielding intersected DEGs. Key drug targets were identified by intersecting these DEGs with the drug targets of active ingredients in TCM. Topological analysis of the PPI network was used to identify key genes. Cell types exhibiting high expression of these genes were designated as key cells. These key cells were subjected to cellular communication analysis and temporal analysis, after which they were classified into subtypes.

RESULTS

HGs significantly improved motor function and prevented dopaminergic neuronal loss in the substantia nigra (SN) of MPTP-treated mice. A total of 34 cell clusters were delineated, with 9 cell types identified, including oligodendrocytes (oligo), neurons, and T cells. We identified 758 intersected DEGs and 13 key drug targets, including Egfr, Ntrk2, Grm5, Htr2c, Bcl2l1. Oligo and neuronal cells were identified as key cells due to higher expression levels of these key genes. In the cellular communication analysis, oligo-neuronal interactions in the blank and model groups, and oligo-OPC and oligo-T cell interactions in the medication group, exhibited the most receptor-ligand interactions. In temporal analysis, both oligo and neuronal cells were differentiated into 9 states, with C1 being the most differentiated.

CONCLUSION

HGs demonstrate neuroprotective effects in MPTP-treated mice. Using single-cell sequencing, we identified five key genes (Egfr, Ntrk2, Grm5, Htr2c, Bcl2l1) and two key cell types (oligo and neuronal) related to HGs in PD. These findings provided a foundation for understanding the molecular mechanisms by which HGs treat PD.

Analytical method for simultaneous quantification of levodopa and carbidopa in the injectable oleogel formulation by HPLC

The developed method for simultaneous detection of levodopa and carbidopa was able to separate the peaks of the drug and sodium bisulfite in the in-vitro release samples and stability samples. Levodopa (LD), a pro-drug of dopamine, is used as the gold standard treatment for Parkinson's disease. It is usually prescribed with carbidopa (CD) to prevent the conversion of levodopa to dopamine peripherally, thus reducing undesirable side effects. Both drugs are unstable at pH 7.4 beyond 24 h due to their oxidation, therefore 0.2% sodium bisulfite is added to the formulation as an antioxidant. The separation was performed by gradient elution using the Luna-C18 column (250 × 4.6 mm, 5 µm) at a flow rate of 1 ml/min. The mobile phase was composed of mobile phase A 30 mM potassium phosphate and acetonitrile (95:5, v/v) with 35 mM tetrabutylammonium hydrogen sulphate and mobile phase B containing 30 mM potassium phosphate and acetonitrile (50:50 v/v). Drug peaks were detected at 280 nm with retention times of 3.05 ± 0.001 min for LD and 3.64 ± 0.001 min for CD. The validation of the method according to US FDA guidelines and results were found to be within acceptable limits. The method was linear from 10-100 µg/ml (r2 = 0.999) and 10-100 µg/ml (r2 = 0.999) for LD and CD, respectively. The developed method was applied to studying the drug release from in-situ gel. The environmental impact of the developed method was evaluated using various greenness assessment tools.

Ideal animal models according to multifaceted mechanisms and peculiarities in neurological disorders: present and challenges

Neurological disorders, encompassing conditions such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS), pose a significant global health challenge, affecting millions worldwide. With an aging population and increased life expectancy, the prevalence of these disorders is escalating rapidly, leading to substantial economic burdens exceeding trillions of dollars annually. Animal models play a crucial role in understanding the underlying mechanisms of these disorders and developing effective treatments. Various species, including rodents, non-human primates, and fruit flies, are utilized to replicate specific aspects of human neurological conditions. However, selecting the ideal animal model requires careful consideration of its proximity to human disease conditions and its ability to mimic disease pathobiology and pharmacological responses. An Animal Model Quality Assessment (AMQA) tool has been developed to facilitate this selection process, focusing on assessing models based on their similarity to human conditions and disease pathobiology. Therefore, integrating intrinsic and extrinsic factors linked to the disease into the study's objectives aids in constructing a biological information matrix for comparing disease progression between the animal model and human disease. Ultimately, selecting an ideal animal disease model depends on its predictive, face, and construct validity, ensuring relevance and reliability in translational research efforts.

Enhancements in Parkinson's Disease Management: Leveraging Levodopa Optimization and Surgical Breakthroughs

Parkinson's disease (PD) is a complex neurological condition caused due to inheritance, environment, and behavior among various other parameters. The onset, diagnosis, course of therapy, and future of PD are thoroughly examined in this comprehensive review. This review also presents insights into pathogenic mechanisms of reactive microgliosis, Lewy bodies, and their functions in the evolution of PD. It addresses interaction complexity with genetic mutations, especially in genes such as UCH-L1, parkin, and α-synuclein, which illuminates changes in the manner dopaminergic cells handle proteins and use proteases. This raises the improved outcomes and life quality for those with PD. Potential treatments for severe PD include new surgical methods like Deep Brain Stimulation (DBS). Further, exploration of non-motor manifestations, such as cognitive impairment, autonomic dysfunction, and others, is covered in this review article. These symptoms have a significant impact on patients' quality of life. Furthermore, one of the emerging therapeutic routes that are being investigated is neuroprotective medicines that aim to prevent the aggregation of α-synuclein and interventions that modify the progression of diseases. The review concludes by stressing the dynamic nature of PD research and the potential game-changing impact of precision medicines on current approaches to therapy.

Comparison of Efficacy and Safety of Device-Based Interventions Versus Pharmacological Therapy in the Management of Patients With Advanced Parkinson's Disease: A Literature Review

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms that profoundly impact patients' quality of life. While pharmacological therapies such as levodopa remain the mainstay of treatment, their long-term use is often limited by motor complications. Device-based interventions, including deep brain stimulation (DBS) and continuous dopaminergic infusions, have emerged as alternatives, promising sustained symptomatic control and reduced medication-related side effects. This systematic review and meta-analysis evaluate the comparative efficacy, safety, and cost-effectiveness of device-based interventions versus pharmacological therapies in the management of advanced PD. A comprehensive search was conducted across multiple databases to identify randomized controlled trials, observational studies, and systematic reviews. Primary outcomes included motor function improvement, quality of life, and adverse events. Meta-analyses were performed, and subgroup analyses explored the effectiveness of specific interventions. Device-based interventions demonstrated superior efficacy over pharmacological therapies, with a pooled effect size (Cohen's d) of 1.12 (95% confidence interval (CI): 0.94-1.29) for motor symptom control and quality of life improvements. Subgroup analyses showed DBS and levodopa-carbidopa intestinal gel to be particularly effective, with levodopa-carbidopa intestinal gel showing a Cohen's d of 1.25 (95% CI: 0.91-1.58). Device-based therapies also reduced medication dosages and associated motor complications. Sensitivity analyses confirmed the robustness of these findings, and no significant publication bias was detected. However, gaps remain in understanding the long-term outcomes and cost-effectiveness of these interventions. Device-based interventions, especially DBS and levodopa-carbidopa intestinal gel, offer superior symptom control and quality of life improvements compared to traditional pharmacological therapies in advanced PD. These findings support the integration of device-based therapies into personalized treatment strategies. Further research is needed to explore long-term outcomes and establish standardized guidelines for their implementation in clinical practice.

Neuroprotective effect of L-DOPA-induced interleukin-13 on striatonigral degeneration in cerebral ischemia

Levodopa (L-DOPA) treatment is a clinically effective strategy for improving motor function in patients with ischemic stroke. However, the mechanisms by which modulating the dopamine system relieves the pathology of the ischemic brain remain unclear. Emerging evidence from an experimental mouse model of ischemic stroke, established by middle cerebral artery occlusion (MCAO), suggested that L-DOPA has the potential to modulate the inflammatory and immune response that occurs during a stroke. Here, we aimed to demonstrate the therapeutic effect of L-DOPA in regulating the systemic immune response and improving functional deficits in mice with ischemia. Transient MCAO led to progressive degeneration of nigrostriatal dopamine neurons and significant rotational behavior in mice. Exogenous L-DOPA treatment attenuated the striatonigral degeneration and reversed motor behavioral impairment. Notably, treatment with L-DOPA significantly increased IL-13 but reduced IFN-γ in infarct lesions. To investigate the role of IL-13 in motor behavior, we stereotaxically injected anti-IL-13 antibodies into the infarct area of the mouse brain one week after MCAO, followed by L-DOPA treatment. The intervention reduced dopamine, IL-13, and IL-10 levels and exacerbated motor function. IL-13 is potentially expressed on CD4 T cells, while IL-10 is mainly expressed on microglia rather than astrocytes. Finally, IL-13 activates the phagocytosis of microglia, which may contribute to neuroprotection by eliminating degenerating neurons. Our study provides evidence that the L-DOPA-activated dopamine system modulates peripheral immune cells, resulting in the expression of anti-inflammatory and neuroprotective cytokines in mice with ischemic stroke.

Assessment of CRISPRa-mediated gdnf overexpression in an In vitro Parkinson's disease model

Introduction

Parkinson's disease (PD) presents a significant challenge in medical science, as current treatments are limited to symptom management and often carry significant side effects. Our study introduces an innovative approach to evaluate the effects of gdnf overexpression mediated by CRISPRa in an in vitro model of Parkinson's disease. The expression of gdnf can have neuroprotective effects, being related to the modulation of neuroinflammation and pathways associated with cell survival, differentiation, and growth.

Methods

We have developed a targeted delivery system using a magnetite nanostructured vehicle for the efficient transport of genetic material. This system has resulted in a substantial increase, up to 200-fold) in gdnf expression in an In vitro model of Parkinson's disease using a mixed primary culture of astrocytes, neurons, and microglia.

Results and Discussion

The delivery system exhibits significant endosomal escape of more than 56%, crucial for the effective delivery and activation of the genetic material within cells. The increased gdnf expression correlates with a notable reduction in MAO-B complex activity, reaching basal values of 14.8 μU/μg of protein, and a reduction in reactive oxygen species. Additionally, there is up to a 34.6% increase in cell viability in an In vitro Parkinson's disease model treated with the neurotoxin MPTP. Our study shows that increasing gdnf expression can remediate some of the cellular symptoms associated with Parkinson's disease in an in vitro model of the disease using a novel nanostructured delivery system.

Transdermal Delivery of Pramipexole Using Microneedle Technology for the Potential Treatment of Parkinson's Disease

Parkinson's disease (PD) is a debilitating neurodegenerative disease primarily impacting neurons responsible for dopamine production within the brain. Pramipexole (PRA) is a dopamine agonist that is currently available in tablet form. However, individuals with PD commonly encounter difficulties with swallowing and gastrointestinal motility, making oral formulations less preferable. Microneedle (MN) patches represent innovative transdermal drug delivery devices capable of enhancing skin permeability through the creation of microconduits on the surface of the skin. MNs effectively reduce the barrier function of skin and facilitate the permeation of drugs. The work described here focuses on the development of polymeric MN systems designed to enhance the transdermal delivery of PRA. PRA was formulated into both dissolving MNs (DMNs) and directly compressed tablets (DCTs) to be used in conjunction with hydrogel-forming MNs (HFMNs). In vivo investigations using a Sprague-Dawley rat model examined, for the first time, if it was beneficial to prolong the application of DMNs and HFMNs beyond 24 h. Half of the patches in the MN cohorts were left in place for 24 h, whereas the other half remained in place for 5 days. Throughout the entire 5 day study, PRA plasma levels were monitored for all cohorts. This study confirmed the successful delivery of PRA from DMNs (Cmax = 511.00 ± 277.24 ng/mL, Tmax = 4 h) and HFMNs (Cmax = 328.30 ± 98.04 ng/mL, Tmax = 24 h). Notably, both types of MNs achieved sustained PRA plasma levels over a 5 day period. In contrast, following oral administration, PRA remained detectable in plasma for only 48 h, achieving a Cmax of 159.32 ± 113.43 ng/mL at 2 h. The HFMN that remained in place for 5 days demonstrated the most promising performance among all investigated formulations. Although in the early stages of development, the findings reported here offer a hopeful alternative to orally administered PRA. The sustained plasma profile observed here has the potential to reduce the frequency of PRA administration, potentially enhancing patient compliance and ultimately improving their quality of life. This work provides substantial evidence advocating the development of polymeric MN-mediated drug delivery systems to include sustained plasma levels of hydrophilic pharmaceuticals.

Eye tracking assessment of Parkinson's disease: a clinical retrospective analysis

Parkinson's disease (PD) presents a significant clinical challenge due to its profound motor and cognitive impacts. Early diagnosis is crucial for implementing effective, stage-based treatment strategies. Recently, eye-tracking technology has emerged as a promising tool for the non-invasive diagnosis and monitoring of various neurological disorders, including PD. This retrospective study analyzed eye-tracking parameters, specifically visually-guided saccades (VGS), in PD patients within a clinical setting. We reviewed eye-tracking data from 62 PD patients, focusing on eye movement performance in horizontal and vertical VGS tasks. Our findings revealed significant correlations between demographic profiles, Mini-Mental State Examination (MMSE) scores, pattern recognition, and spatial working memory tests with saccadic performance in PD patients. Despite the retrospective nature of the study, our results support the potential of eye-tracking technology as a valuable diagnostic tool in PD assessment and monitoring. Future research should prioritize longitudinal studies and more comprehensive assessments to further understand and enhance the clinical application of eye-tracking in PD.

Unveiling the neuroprotective potential of dietary polysaccharides: a systematic review

Central nervous system (CNS) disorders present a growing and costly global health challenge, accounting for over 11% of the diseases burden in high-income countries. Despite current treatments, patients often experience persistent symptoms that significantly affect their quality of life. Dietary polysaccharides have garnered attention for their potential as interventions for CNS disorders due to their diverse mechanisms of action, including antioxidant, anti-inflammatory, and neuroprotective effects. Through an analysis of research articles published between January 5, 2013 and August 30, 2023, encompassing the intervention effects of dietary polysaccharides on Alzheimer's disease, Parkinson's disease, depression, anxiety disorders, autism spectrum disorder, epilepsy, and stroke, we have conducted a comprehensive review with the aim of elucidating the role and mechanisms of dietary polysaccharides in various CNS diseases, spanning neurodegenerative, psychiatric, neurodevelopmental disorders, and neurological dysfunctions. At least four categories of mechanistic bases are included in the dietary polysaccharides' intervention against CNS disease, which involves oxidative stress reduction, neuronal production, metabolic regulation, and gut barrier integrity. Notably, the ability of dietary polysaccharides to resist oxidation and modulate gut microbiota not only helps to curb the development of these diseases at an early stage, but also holds promise for the development of novel therapeutic agents for CNS diseases. In conclusion, this comprehensive review strives to advance therapeutic strategies for CNS disorders by elucidating the potential of dietary polysaccharides and advocating interdisciplinary collaboration to propel further research in this realm.

Evaluating Manganese, Zinc, and Copper Metal Toxicity on SH-SY5Y Cells in Establishing an Idiopathic Parkinson's Disease Model

Parkinson's disease (PD) is a neurodegenerative condition marked by loss of motor coordination and cognitive impairment. According to global estimates, the worldwide prevalence of PD will likely exceed 12 million cases by 2040. PD is primarily associated with genetic factors, while clinically, cases are attributed to idiopathic factors such as environmental or occupational exposure. The heavy metals linked to PD and other neurodegenerative disorders include copper, manganese, and zinc. Chronic exposure to metals induces elevated oxidative stress and disrupts homeostasis, resulting in neuronal death. These metals are suggested to induce idiopathic PD in the literature. This study measures the effects of lethal concentration at 10% cell death (LC10) and lethal concentration at 50% cell death (LC50) concentrations of copper, manganese, and zinc chlorides on SH-SY5Y cells via markers for dopamine, reactive oxygen species (ROS) generation, DNA damage, and mitochondrial dysfunction after a 24 h exposure. These measurements were compared to a known neurotoxin to induce PD, 100 µM 6-hydroxydopamine (6-ODHA). Between the three metal chlorides, zinc was statistically different in all parameters from all other treatments and induced significant dopaminergic loss, DNA damage, and mitochondrial dysfunction. The LC50 of manganese and copper had the most similar response to 6-ODHA in all parameters, while LC10 of manganese and copper responded most like untreated cells. This study suggests that these metal chlorides respond differently from 6-ODHA and each other, suggesting that idiopathic PD utilizes a different mechanism from the classic PD model.

Should continuous dopaminergic stimulation be a standard of care in advanced Parkinson's disease?

The standard of care is a term that refers to the level of care, skill, and treatment that a healthcare provider should offer to a patient based on the current scientific evidence and the level of medical knowledge available in the field. For Parkinson's disease (PD), the standard care is mostly considered to be oral treatment with dopaminergic drugs, particularly levodopa which remains the 'gold standard'. However, effective management with levodopa during the later stages of the disease becomes increasingly challenging due to the ongoing neurodegenerative process, the consequences of its pulsatile dopaminergic stimulation, and the gastrointestinal barriers to effective drug absorption. As a result, the concept of applying continuous dopaminergic stimulation has emerged with infusion therapies (continuous subcutaneous apomorphine, levodopa-carbidopa intestinal gel, and levodopa-entacapone-carbidopa intestinal gel infusion). These therapies seek to provide continuous stimulation of striatal dopamine receptors that is efficient not only in alleviating clinical symptoms, but also in delaying, reducing, and possibly preventing the onset of levodopa-related motor (fluctuations, dyskinesia) and non-motor complications; and they are also associated with clinically relevant side effects. Clinical studies and real-life experience support the notion that infusion therapies should be accepted as part of the standard of care for patients with advanced PD who have refractory, severe, and disabling motor complications that affect their quality of life. However, they should be considered based on the needs of individualized patients and the access to these advanced therapies needs to be made more accessible to the general PD population.