Multimodal dopamine transporter (DAT) imaging and magnetic resonance imaging (MRI) to characterise early Parkinson's disease

How can MSI enhance our understanding of ASO distribution?

In the dynamic field of drug discovery and development, a comprehensive understanding of drug absorption, distribution, metabolism, excretion, and toxicity is crucial. Mass spectrometry imaging (MSI) has become a key analytical tool in the pharmaceutical industry, allowing evaluation of drug biodistribution and molecular profiles. Antisense oligonucleotides (ASOs) are emerging drug candidates for treating neurologic diseases. This review explores the potential of MSI in investigating ASOs' spatial distribution within neurological disease models. Here, we focus on multimodal molecular imaging to gain insights into ASO distribution, simultaneously with a better understanding of the molecular pathways affected by ASOs. An improved understanding of therapeutic ASOs in tissue will potentially improve neurologic therapies, emphasizing their importance in patient care.

Optimization of Parkinson's disease therapy with plant extracts and nutrition's evolving roles

Parkinson's disease (PD) is a neurodegenerative disease characterized by death of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Death of dopaminergic cells in the SNpc leads to manifestations of motor dysfunction and non-motor symptoms of PD. The progression of PD symptoms severely affects the quality of life of patients and poses socio-economic problems to families and society at large. The clinical and neuropathological characteristics of PD are triggered by multiple factors such as oxidative stress, neuroinflammation, mitochondrial dysfunction, and protein aggregation. Notwithstanding the advancements in pharmacological therapy in PD management, there is burgeoning interest in alternative and complementary approaches, essentially nutrition and plant extracts strategies. This review gives widespread analysis of the role of nutrition and plant extracts in the management of PD. Studies that investigated the effects of various dietary compounds and plant extract on PD symptoms and progression were reviewed from existing literatures. Nutraceuticals, including vitamins and phytochemicals such as Mucuna pruriens have shown potential neuroprotective functions in preclinical and clinical studies. Indeed, these strategies ameliorate mitochondrial dysfunction, oxidative stress, and neuroinflammation, all which are implicated in the pathogenesis of PD. The neuroprotective mechanisms of nutrition and plant extracts in PD, with emphasis on their capacity to target multiple pathways implicated in PD are discussed. Additionally, challenges and limitations related with translating preclinical findings into clinical practice including standardization of dosing regimens, bioavailability, and inter-individual variability are discussed. Largely, this review elucidates on the role of nutrition and plant extracts as adjunctive therapy in PD management.

Structural bioinformatics studies of serotonin, dopamine and norepinephrine transporters and their AlphaFold2 predicted water-soluble QTY variants and uncovering the natural mutations of L->Q, I->T, F->Y and Q->L, T->I and Y->F

Monoamine transporters including transporters for serotonin, dopamine, and norepinephrine play key roles in monoaminergic synaptic signaling, involving in the molecular etiology of a wide range of neurological and physiological disorders. Despite being crucial drug targets, the study of transmembrane proteins remains challenging due to their localization within the cell membrane. To address this, we present the structural bioinformatics studies of 7 monoamine transporters and their water-soluble variants designed using the QTY code, by systematically replacing the hydrophobic amino acids leucine (L), valine (V), isoleucine (I) and phenylalanine (F) with hydrophilic amino acids (glutamine (Q), threonine (T) and tyrosine (Y). The resulting QTY variants, despite significant protein transmembrane sequence differences (44.27%-51.85%), showed similar isoelectric points (pI) and molecular weights. While their hydrophobic surfaces significantly reduced, this change resulted in a minimal structural alteration. Quantitatively, Alphafold2 predicted QTY variant structures displayed remarkable similarity with RMSD 0.492Å-1.619Å. Accompanied by the structural similarities of substituted amino acids in the context of 1.5Å electron density maps, our study revealed multiple QTY and reverse QTY variations in genomic databases. We further analyzed their phenotypical and topological characteristics. By extending evolutionary game theory to the molecular foundations of biology, we provided insights into the evolutionary dynamics of chemically distinct alpha-helices, their usage in different chemotherapeutic applications, and open possibilities of diagnostic medicine. Our study rationalizes that QTY variants of monoamine transporters may not only become distinct tools for medical, structural, and evolutionary research, but these transporters may also emerge as contemporary therapeutic targets, providing a new approach to treatment for several conditions.

Corticostriatal beta oscillation changes associated with cognitive function in Parkinson's disease

Cognitive impairment is the most frequent non-motor symptom in Parkinson's disease and is associated with deficits in a number of cognitive functions including working memory. However, the pathophysiology of Parkinson's disease cognitive impairment is poorly understood. Beta oscillations have previously been shown to play an important role in cognitive functions including working memory encoding. Decreased dopamine in motor cortico-striato-thalamo-cortical (CSTC) circuits increases the spectral power of beta oscillations and results in Parkinson's disease motor symptoms. Analogous changes in parallel cognitive CSTC circuits involving the caudate and dorsolateral prefrontal cortex (DLPFC) may contribute to Parkinson's disease cognitive impairment. The objective of our study is to evaluate whether changes in beta oscillations in the caudate and DLPFC contribute to cognitive impairment in Parkinson's disease patients. To investigate this, we used local field potential recordings during deep brain stimulation surgery in 15 patients with Parkinson's disease. Local field potentials were recorded from DLPFC and caudate at rest and during a working memory task. We examined changes in beta oscillatory power during the working memory task as well as the relationship of beta oscillatory activity to preoperative cognitive status, as determined from neuropsychological testing results. We additionally conducted exploratory analyses on the relationship between cognitive impairment and task-based changes in spectral power in additional frequency bands. Spectral power of beta oscillations decreased in both DLPFC and caudate during working memory encoding and increased in these structures during feedback. Subjects with cognitive impairment had smaller decreases in caudate and DLPFC beta oscillatory power during encoding. In our exploratory analysis, we found that similar differences occurred in alpha frequencies in caudate and theta and alpha in DLPFC. Our findings suggest that oscillatory power changes in cognitive CSTC circuits may contribute to cognitive symptoms in patients with Parkinson's disease. These findings may inform the future development of novel neuromodulatory treatments for cognitive impairment in Parkinson's disease.

Highly Sensitive and Selective Dopamine Determination in Real Samples Using Au Nanoparticles Decorated Marimo-like Graphene Microbead-Based Electrochemical Sensors

A sensitive and selective electrochemical dopamine (DA) sensor has been developed using gold nanoparticles decorated marimo-like graphene (Au NP/MG) as a modifier of the glassy carbon electrode (GCE). Marimo-like graphene (MG) was prepared by partial exfoliation on the mesocarbon microbeads (MCMB) through molten KOH intercalation. Characterization via transmission electron microscopy confirmed that the surface of MG is composed of multi-layer graphene nanowalls. The graphene nanowalls structure of MG provided abundant surface area and electroactive sites. Electrochemical properties of Au NP/MG/GCE electrode were investigated by cyclic voltammetry and differential pulse voltammetry techniques. The electrode exhibited high electrochemical activity towards DA oxidation. The oxidation peak current increased linearly in proportion to the DA concentration in a range from 0.02 to 10 μM with a detection limit of 0.016 μM. The detection selectivity was carried out with the presence of 20 μM uric acid in goat serum real samples. This study demonstrated a promising method to fabricate DA sensor-based on MCMB derivatives as electrochemical modifiers.

18F-FP-CIT dopamine transporter PET findings in the striatum and retina of type 1 diabetic rats

PURPOSE

Noninvasive methods used in clinic to accurately detect DA neuron loss in diabetic brain injury and diabetic retinopathy have not been reported up to now. ¹⁸F-FP-CIT is a promising dopamine transporter (DAT) targeted probe. Our study first applies ¹⁸F-FP-CIT PET imaging to assess DA neuron loss in the striatum and retina of T1DM rat model.

METHODS

T1DM rat model was induced by a single intraperitoneal injection of streptozotocin (STZ) (65 mg kg^-1, ip). ¹⁸F-FP-CIT uptake in the striatum and retina was evaluated at 4 weeks, 8 weeks and 12 weeks after STZ injection. The mean standardized uptake value (SUVmean) and the maximum standardized uptake value (SUVmax) were analyzed. Western blot was performed to confirm the DAT protein levels in the striatum and retina.

RESULTS

PET/CT results showed that the SUV of ¹⁸F-FP-CIT was significantly reduced in the diabetic striatum and retina compared with the normal one from 4-week to 12-week (p < 0.0001). Western blots showed that DAT was significantly lower in the diabetic striatum and retina compared to the normal one for all three time points (p < 0.05). The results from Western blots confirmed the findings in PET imaging studies.

CONCLUSIONS

DA neuron loss in the striatum and retina of T1DM rat model can be non-invasively detected with PET imaging using ¹⁸F-FP-CIT targeting DAT. ¹⁸F-FP-CIT PET imaging may be a useful tool used in clinic for DR and diabetic brain injury diagnosis in future. The expression level of DAT in striatum and retina may act as a new biomarker for DR and diabetic brain injury diagnosis.

Outcome Measures for Disease-Modifying Trials in Parkinson's Disease: Consensus Paper by the EJS ACT-PD Multi-Arm Multi-Stage Trial Initiative

BACKGROUND

Multi-arm, multi-stage (MAMS) platform trials can accelerate the identification of disease-modifying treatments for Parkinson's disease (PD) but there is no current consensus on the optimal outcome measures (OM) for this approach.

OBJECTIVE

To provide an up-to-date inventory of OM for disease-modifying PD trials, and a framework for future selection of OM for such trials.

METHODS

As part of the Edmond J Safra Accelerating Clinical Trials in Parkinson Disease (EJS ACT-PD) initiative, an expert group with Patient and Public Involvement and Engagement (PPIE) representatives' input reviewed and evaluated available evidence on OM for potential use in trials to delay progression of PD. Each OM was ranked based on aspects such as validity, sensitivity to change, participant burden and practicality for a multi-site trial. Review of evidence and expert opinion led to the present inventory.

RESULTS

An extensive inventory of OM was created, divided into: general, motor and non-motor scales, diaries and fluctuation questionnaires, cognitive, disability and health-related quality of life, capability, quantitative motor, wearable and digital, combined, resource use, imaging and wet biomarkers, and milestone-based. A framework for evaluation of OM is presented to update the inventory in the future. PPIE input highlighted the need for OM which reflect their experience of disease progression and are applicable to diverse populations and disease stages.

CONCLUSION

We present a range of OM, classified according to a transparent framework, to aid selection of OM for disease-modifying PD trials, whilst allowing for inclusion or re-classification of relevant OM as new evidence emerges.

The Key Role of Magnetic Resonance Imaging in the Detection of Neurodegenerative Diseases-Associated Biomarkers: A Review

Neurodegenerative diseases (NDs), including chronic disease such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis, and acute diseases like traumatic brain injury and ischemic stroke are characterized by progressive degeneration, brain tissue damage and loss of neurons, accompanied by behavioral and cognitive dysfunctions. So far, there are no complete cures for NDs; thus, early and timely diagnoses are essential and beneficial to patients' treatment. Magnetic resonance imaging (MRI) has become one of the advanced medical imaging techniques widely used in the clinical examination of NDs due to its non-invasive diagnostic value. In this review, research published in English in current decade from PubMed electronic database on the use of MRI to detect specific biomarkers of NDs was collected, summarized, and discussed, which provides valuable suggestions for the early diagnosis, prevention, and treatment of NDs in the clinic.

Progress of advanced nanomaterials in diagnosis of neurodegenerative diseases

Neurodegenerative diseases (NDDs) encompass a wide range of clinically and pathologically diverse diseases characterized by progressive long-term cognitive decline, memory and function loss in daily life. Due to the lack of effective drugs and therapeutic strategies for preventing or delaying neurodegenerative progression, it is urgent to diagnose NDDs as early and accurately as possible. Nanomaterials, emerged as one of the most promising materials in the 21st century, have been widely applied and play a significant role in diagnosis and treatment of NDDs because of their remarkable properties including stability, prominent biocompatibility, unique structure, novel physical and chemical characteristics. In this review, we outlined general strategies for the application of different types of advanced materials in early and staged diagnosis of NDDs in vivo and in vitro. According to applied technology, in vivo research mainly involves magnetic resonance, fluorescence, and surface enhanced Raman imaging on structures of brain tissues, cerebral vessels and related distributions of biomarkers. In vitro research is focused on the detection of fluid biomarkers in cerebrospinal fluid and peripheral blood based on fluorescence, electrochemical, Raman and surface plasmon resonance techniques. Finally, we discussed the current challenges and future perspectives of biomarker-based NDDs diagnosis as well as potential applications regarding advanced nanomaterials.