Search Results (7,897)

This study investigates the contemporaneous associations between investor sentiment, market microstructure, and daily sectoral returns on Boursa Kuwait. The analysis utilizes daily data spanning from January 2021 to May 2025, integrating sectoral returns, trading volume, liquidity, and volatility proxies alongside a manually constructed sentiment index derived from financial news and market announcements. Ordinary least squares (OLS) regressions were estimated for each sector. Baseline specifications incorporate the High–Low Range, Parkinson volatility, and trading volume, while expanded models include the Log_Amihud illiquidity measure, CC_Volatility, Brent crude oil returns, the Boursa Kuwait All Share Index (AllShare_Return), and the first difference of Central Bank of Kuwait discount rate (D_CBK_DiscountRate). Initial results indicate that investor sentiment is significantly associated with returns in several sectors, though the direction and magnitude of these associations are heterogeneous. Upon controlling for broader market and macroeconomic conditions, the sentiment coefficient remains statistically significant in the Technology and Health Care sectors, with the Technology coefficient changing from positive in the baseline specification to negative in the expanded specification. Liquidity and volatility measures continue to exhibit sector-specific associations. AllShare_Return is positively and statistically significantly associated with returns across most sectors, whereas Brent_Return and the D_CBK_DiscountRate show limited, sector-specific relationships. These findings suggest that broader market conditions account for an important part of daily sectoral return variation, whereas the associations of investor sentiment and market microstructure with returns continue to differ across sectors. Full article

Background/Objectives: Intranasal delivery is a promising noninvasive approach to enhance central nervous system drug delivery in Parkinson’s disease (PD), potentially bypassing the blood–brain barrier and minimizing gastrointestinal side effects. This review summarizes clinical trials and translational evidence for intranasal PD therapies by treatment options and intent, highlighting key challenges in efficacy, pharmacokinetics, and safety. Methods: We reviewed human clinical trials, preclinical and pilot studies, and pharmacokinetic investigations of intranasal therapies for PD. Comparisons to established treatments were included in context. Only PD-specific clinical studies were analyzed. Therapies were grouped by rescue, antioxidant/metabolic/hormonal, and biologic or cell-based approaches, with continuous-delivery systems reviewed separately. Results: Intranasal rescue therapies, such as apomorphine, provide rapid improvement during OFF episodes (periods when the effects of PD medications fade and symptoms reappear), but tolerability issues and nasal irritation limit usage. Early-phase studies suggest intranasal delivery enables quick symptom relief and favorable pharmacokinetics, though most trials are small and focus on feasibility. New approaches include antioxidants, neurotrophic factors, gene therapy, and cell-based methods, with advanced formulations enhancing nasal retention and brain uptake. However, more translational evidence and long-term safety data are needed. Conclusions: Intranasal therapies for PD offer rapid rescue and expand options beyond standard drugs. Large, well-designed trials are needed to confirm efficacy, long-term safety, and optimal formulations. Intranasal delivery remains an emerging but potentially transformative strategy requiring further clinical research. Full article

Neurological disorders like Alzheimer’s disease, Parkinson’s disease, and epilepsy are becoming major causes of disability and mortality worldwide, and their prevalence is expected to rapidly increase with the aging of the population. These diseases develop silently, with irreversible neuronal damage often occurring decades before any clinical signs of illness are noticed, making early diagnosis and treatment difficult. The presymptomatic period greatly restricts the effectiveness of therapeutic interventions and reduces the possibility of disease-modifying interventions. Traditional diagnostic methods based on clinical assessment, neuroimaging, and invasive biomarkers are not sensitive enough to identify the disease at an early stage and are expensive to the healthcare system. The latest artificial intelligence (AI) technology and machine learning (ML) approaches, together with digital biomarkers obtained from eye tracking, facial expressions, speech analysis, motor dynamics, electrophysiology, wearable devices, and passive sensing, offer promising non-invasive alternatives for early detection of diseases. However, most reported performance metrics are derived from retrospective or pre-validated datasets, and prospective external validation remains limited. This narrative review synthesizes current evidence on AI-driven digital biomarkers for early detection of neurological diseases, examining disease-specific applications, methodological approaches, and challenges in clinical practices. We emphasize that clinical utility is task specific and dependent on disease stage, validation design, clinical endpoints, cost, workflow integration, and availability of disease-modifying therapies. We also note that much of the evidence summarized here derives from retrospective, case-control, or internally validated datasets and that prospective, patient-independent, and external validation with clinically meaningful endpoints remains limited. Reported performance figures should be read as proof-of-concept evidence rather than as evidence of demonstrated clinical readiness. We highlight promising future directions, including federated learning, explainable AI, and precision neurology approaches, while acknowledging that most applications remain investigational and require prospective validation before broad clinical deployment. Full article

Background: Parkinson’s disease (PD) is a progressive neurodegenerative disorder causing disabling motor dysfunction and substantial socioeconomic burden. Photobiomodulation (PBM), a noninvasive red/near-infrared light therapy, has shown preclinical promise, but its clinical efficacy and safety in PD remain uncertain. Objectives: To systematically evaluate the efficacy and safety of PBM on motor outcomes in PD. Methods: This PRISMA-compliant systematic review was prospectively registered in PROSPERO (CRD420261411269). Databases were searched through May 2026. Randomized and non-randomized trials in adults with PD were included. Two reviewers independently screened studies, extracted data, and assessed risk of bias (RoB 2.0; ROBINS-I). Where data permitted, random-effects meta-analyses used mean difference (MD) with REML estimation and Hartung–Knapp–Sidik–Jonkman confidence intervals. Results: Eight trials (n = 279) were included, exhibiting substantial heterogeneity in wavelength, device type, stimulation sites, and dosimetry. PBM was safe and well tolerated, with only minor adverse effects. Meta-analysis of four RCTs found no significant effect on MDS-UPDRS-III (MD = −1.37 points, 95% CI: −5.55 to 2.80; I² = 20.6%) or TUG (MD = −0.52 s, 95% CI: −5.03 to 3.99; I² = 55.1%). An exploratory TMWT meta-analysis (k = 2) yielded MD = −0.65 s (95% CI: −1.78 to 0.49; I² = 0.0%), with direction consistently favoring PBM. Individual effect sizes ranged from negligible (d = 0.03–0.06) to small-to-moderate (d = 0.41). Conclusions: PBM appears safe, feasible, and acceptable in PD, but current evidence does not support clinically meaningful motor benefits. Heterogeneous protocols, small samples, and absent target-engagement biomarkers limit definitive interpretation. Well-powered standardized trials with mechanistic endpoints are needed. Full article

Background: The most effective pharmacological treatment for Parkinson’s disease (PD) remains levodopa, whose responsiveness is distinguished into two temporally and mechanistically distinct components: the short-duration response (SDR), which lasts hours, closely paralleling drug plasma concentration, and the long-duration response (LDR), which derives from prolonged administration of levodopa and persists for days to weeks after drug discontinuation. The mechanisms underlying the LDR and, in particular, the behavior in early PD patients are incompletely understood. This review aims to gather current evidence on the pharmacodynamics, neurobiological substrate, natural history, and clinical implications of the LDR, with a specific focus on early PD patients. Methods: A narrative review was conducted based on a selection of original research articles, clinical studies, and reviews identified through PubMed/MEDLINE, covering the period from January 1995 to July 2026. Studies were selected for their methodological relevance to the characterization of LDR in drug-naive or early-stage PD patients, including pharmacodynamic studies, neuroimaging investigations, and neurophysiological assessments. Results: Evidence consistently demonstrates that the LDR is a pharmacodynamically distinct component of levodopa response, present from the earliest stages of dopaminergic therapy. In drug-naive patients, the LDR represents a quantitatively substantial fraction of total levodopa benefit, and it is linked to modifications in cortical excitability, dopaminergic neuroplasticity, and motor learning. Structural neuroimaging identifies predisposing gray matter features in motor cortex regions. Whether LDR magnitude declines with disease and treatment duration, and thereby underlies the emergence of motor fluctuations, remains disputed across studies. This discrepancy appears attributable, at least in part, to differences in how the LDR is measured (direct washout assessment versus inference against a projected untreated trajectory) rather than necessarily to divergent underlying biology. Conclusions: The LDR to levodopa represents a neurobiologically and clinically significant dimension of levodopa response. Its characterization in early PD patients may refine therapeutic strategies, inform the design of neuroprotection trials, and open new possibilities for precision medicine approaches. Full article

Objectives: Adults exposed to the Bacillus Calmette–Guérin (BCG) vaccine demonstrate a reduced incidence of Parkinson’s disease (PD). This retrospective study evaluated whether early-life BCG vaccination predicts a long-term reduction in PD incidence during aging. Methods: Published age-adjusted incidence rates (AAIRs) of PD (2002–2021) were structured into single-age birth cohorts. Missing values were calculated via interpolation and shuffling simulations. Cohorts were categorized into three historical BCG policy periods: unvaccinated controls (born 1945–1949), vaccinated at age 12 (born 1950–1954), and vaccinated as newborns (born 1955–1959). AAIRs were compared at identical cross-sectional ages (57 and 62 years), applying an environmental drift penalty to control for temporal improvements. Results: In men, the age 12 policy showed a 21.8% AAIR reduction at age 57, which attenuated to 4.4% by age 62; the newborn policy showed a sustained reduction (25.8% at age 57; 20.4% at age 62). In women, the age 12 policy yielded a 67.5% reduction at age 57 (33.1% at age 62), while the newborn policy showed a 56.8% reduction at age 57 (44.0% at age 62). Conclusions: Early-life BCG vaccination is associated with reduced later-life PD incidence, displaying a profound sex-dependent effect favoring females. Newborn vaccination provides long-term resistance as well. Full article

Parkinsonian syndromes comprise overlapping neurodegenerative and non-degenerative disorders, making aetiological diagnosis difficult, while existing procedural guidance does not fully integrate tracer-specific biology with clinical decision-making, multimodal strategies, and emerging quantitative and pathology-directed biomarkers. This review synthesises evidence on the molecular targets, radiopharmaceutical characteristics, biological interpretation, and clinical applications of dopaminergic single-photon emission computed tomography (SPECT) and positron emission tomography (PET), focusing on the dopamine transporter (DAT), aromatic L-amino acid decarboxylase (AADC), vesicular monoamine transporter type 2 (VMAT2), dopamine D₂/D₃ receptors, differential diagnosis, semiquantification, kinetic modelling, and artificial intelligence-assisted interpretation. The evidence confirms that DAT SPECT with [¹²³I]ioflupane ([¹²³I]FP-CIT) remains the most established method for demonstrating or arguing against presynaptic nigrostriatal dysfunction, but an abnormal result cannot establish aetiology, and a normal result can redirect evaluation towards non-degenerative mimics; target-specific PET provides complementary biological information, although availability, standardisation, and prospective validation remain limiting. By additionally integrating genetic and prodromal applications, question-driven multimodal imaging, emerging acquisition approaches, α-synuclein imaging and seed amplification assays, and contemporary biological staging frameworks, this review extends procedural guidance and positions dopaminergic imaging as a targeted functional biomarker selected according to the unresolved clinical question rather than as a stand-alone disease label. Full article

Curcumin and natural curcuminoids possess numerous beneficial properties, including antioxidant, antitumor, and anti-inflammatory effects. However, their application is challenging because of instability and rapid metabolism. Cyclic C₅-curcuminoids, a subgroup of curcuminoids, are chemically more stable and less susceptible to hydrolysis or metabolism. In our study, seven synthetic compounds—five cyclic C₅-curcuminoids (compounds 8, 9, 11, 12, and 13) and two cyclic chalcones (compounds 4 and 5)—were examined using an in vitro 6-hydroxydopamine-induced neuronal damage model established with all-trans retinoic acid-differentiated SH-SY5Y and BV-2 microglial cells. The antioxidant, anti-apoptotic (including ferroptosis markers (iron, GSH/GSSG, and malondialdehyde)), apoptotic (PARP, cytochrome c, caspase 9, active caspase-3, and oligonucleosome release), and anti-inflammatory effects of these compounds were also investigated. Compounds 5, 9, 12, and 13 significantly decreased reactive oxygen species production (percentage changes: 5: 28.9%; 9: 32%; 12: 29.8%; 13: 49.2%) and increased antioxidant capacity (percentage changes: 5: 63.4%; 9: 85.8%; 12: 31.2%; 13: 85.9%) and antioxidant enzyme activity (catalase, superoxide dismutase, and glutathione peroxidase) in SH-SY5Y cells. Compounds 5, 9, and 12 decreased microglial activation by downregulating Iba1 expression (fold changes: 5: 0.73; 9: 0.39; 12: 0.33) and decreasing glutamate concentration (percentage changes: 5: 26.5%; 9: 41.2%; 12: 27.3%). Together with compound 13, they reduced pro-inflammatory cytokine (IL-6, TNFα) secretion and induced anti-inflammatory cytokine (IL-10) release in SH-SY5Y and BV-2 cells. Based on these results, the blood–brain barrier penetrations of compounds 5, 9, 12, and 13 were also investigated. The highest blood–brain barrier penetration was observed for compound 12 (P_app value 13.6 × 10⁻⁶ cm/s). Synthetic cyclic C₅-curcuminoids derived from curcumin overcome the limitations of stability and bioavailability and exhibit strong antioxidant, anti-inflammatory, and anti-apoptotic effects, making them promising candidates for treating neurodegenerative diseases. Full article

Both RIT1 and RIT2 are members of the RAS superfamily of small GTPases, which regulate various cellular processes. RIT1 is widely expressed, whereas RIT2 is primarily found in neuronal tissues. Dysregulation of these proteins has been associated with several human diseases, including Noonan syndrome, cancer, Parkinson’s disease, autism, and schizophrenia. Although RIT1 and RIT2 are often compared to classical RAS proteins, they exhibit distinct regulatory and biochemical properties. Here, we demonstrate that RIT1 differs from classical RAS in GTPase cycling. Unlike classical RAS proteins, RIT1 did not respond to SOS1-mediated nucleotide exchange or p120GAP-stimulated GTP hydrolysis under cell-free conditions. These results imply that RIT1 may depend on regulatory mechanisms that differ from those of classical RAS proteins. However, the relevant physiological regulators remain unknown. Disease-associated RIT1 mutations cluster around the P-loop and Switch II regions. In this transient overexpression screening system, however, these mutations had only a modest effect on the canonical MAPK, PI3K/AKT, and JNK signaling pathways in HEK293T overexpression experiments. This suggests the existence of additional context-specific effectors and regulatory factors. We demonstrate that RIT1 and RIT2 interact with membrane lipids via a basic C-terminal extension. The KRLK-containing region contributes to the binding of phosphatidylserine and phosphoinositides. Charge-reversal mutations disrupt lipid interactions and liposome binding, supporting the functional importance of this region. In a reconstituted liposome system, galectin-3 and LZTR1, but not galectin-1, reduced the interaction of GDP-loaded RIT1 and RIT2 with liposomes. These results suggest that accessory proteins may influence RIT membrane interactions. However, their cellular relevance requires further validation. Together, our findings provide biochemical insights into RIT GTPase regulation and its interactions with membrane lipids under cell-free conditions. Full article

The discovery of the glymphatic system and meningeal lymphatic vessels established that the brain possesses an organized lymphatic clearance network that drains to the deep cervical lymphatics. Disruption of this system has been suggested to contribute to the accumulation of pathogenic proteins implicated in neurodegeneration. Cervical lymphatic reconstruction has been associated with some neurological benefit in Alzheimer’s and Parkinson’s disease, and preclinical work has demonstrated that noninvasive manipulation of superficial cervical lymphatics can increase cerebrospinal fluid outflow. Whether noninvasive cervicofacial lymphedema therapy can produce comparable neurological effects remains unknown. We report two men with Parkinson’s disease (Hoehn and Yahr stages 2.5 and 3) treated with a standardized cervicofacial lymphedema therapy protocol targeting cervical and facial lymphatic pathways. Total MDS-UPDRS scores decreased by 19 points (34.5%) in Patient 1 and 5 points in Patient 2. The reduction in Patient 1 exceeded the published threshold for clinically meaningful total-score improvement. Benefits were reproducible and session-linked, and were accompanied by motor and non-motor gains in cognition, alertness, mood, energy, and sleep; interruption of therapy was associated with return toward baseline. Cervicofacial lymphedema therapy may represent a low-risk, noninvasive intervention hypothesized to influence brain lymphatic clearance in Parkinson’s disease. Full article

Dysregulation of target genes of nonsense-mediated decay (NMD) in the brain remains sparsely known in tauopathies. PS19 transgenic mice expressing human mutant P301S tau were evaluated for levels of lncRNA Gas5, a target of NMD. The results show Gas5 decreased in the brains of PS19 mice as they aged. We evaluated the consequences of blocking the NMD-mediated turnover of Gas5 using a small molecule administered intranasally to PS19 mice. The results show NPC86 disassociated Upf1 and Gas5, thereby hindering NMD. NPC86 treatment increased Gas5 levels in the cortex of male PS19 mice concurrent with a highly significant decrease in pTau S214 and neuroinflammatory genes while increasing insulin signaling. Consequently, digital spatial profiling identified Gas5-regulated genes and pathways. NPC86 treatment enhanced neuronal homeostasis, synaptic vesicle transport and mitochondrial function and downregulated neuroinflammatory pathways. The nodal genes in Parkinson’s signaling pathway, the multiple sclerosis signaling pathway, the Gα(s) signaling pathway, the neuroinflammation signaling pathway, and the interferon gamma signaling pathway were decreased in response to NPC86. The study demonstrates the potential of selectively stabilizing NMD-target lncRNA Gas5 levels to alleviate early neurodegenerative pathology in tauopathy. Full article

Mesenchymal stromal cells (MSCs) have emerged as a promising therapeutic platform for central nervous system disorders, including neurodegenerative diseases and lysosomal storage disorders (LSDs). This review examines MSC mechanisms of action—paracrine activity, immunomodulation, antioxidant effects, TFEB-mediated autophagy regulation, and enzymatic cross-correction in LSDs—while critically assessing translational challenges. We provide a comparative analysis of MSC sources, administration routes, dosing regimens, and safety profiles, with emphasis on hemocompatibility and thrombotic risks. The evidence base for MSC efficacy in amyotrophic lateral sclerosis, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and LSDs is systematically reviewed, highlighting both promising signals and limitations. MSC-derived extracellular vesicles are discussed as a cell-free alternative with improved safety and potential blood–brain barrier interaction. We propose an individualized monitoring framework integrating clinical scales, biomarkers, and neuroimaging. Despite preclinical promise, the field faces major hurdles: product standardization, optimal dosing, and the need for large, randomized controlled trials. The most rational path forward lies in combination strategies—MSCs as adjuncts to gene or enzyme replacement therapy—and engineered platforms for sustained delivery. This review provides a roadmap for translational decision-making and identifies critical gaps that must be addressed before MSC-based therapies can be integrated into routine neurological practice. Full article

Heritability in Parkinson’s disease (PD) may be driven by rare variants (RVs), but genetic data for Chinese cohorts remain limited. We investigated the relationship between RVs and the risk and phenotype of PD by performing targeted exome sequencing of 29 PD candidate genes in 311 late-onset, sporadic Chinese PD patients and 699 local controls. A total of 174 RVs (that were likely deleterious using in silico prediction tools) were identified in 27 of the 29 genes sequenced. Mean RV burden was higher (1.178 vs. 0.478, p = 1.26 × 10⁻²⁴) and HLA-DRB5 p.Val104ArgfsTer26 was enriched in PD patients (0.207 vs. 0.000, p < 0.0003) compared with controls. Gene-based RV carrier status in PD patients was then examined for correlation with phenotypic characteristics. The RV carrier status of LRRK2 and HLA-DRB5 was associated with tremor, SREBF1 with gait disturbance, and SYNJ1 and SCARB2 with motor fluctuations. Earlier onset age and neuropsychiatric symptoms were associated with GBA1 variants. Olfactory deficit, autonomic disturbance, anxiety and depression were associated with variants in SLC44A1, HLA-DRB5, and SCARB2 respectively. Our results demonstrated a prominent RV burden in Chinese PD and illustrated the importance of genetic influence on the risk and phenotype of sporadic PD. Further studies are warranted to correlate these genes with putative pathogenic pathways. Full article

Background: Diabetic retinopathy (DR) and Parkinson’s disease (PD) are prevalent, progressive disorders that cause irreversible visual impairment and motor dysfunction, respectively. Increasing evidence suggests that retinal alterations may precede and predict neurodegeneration in PD, indicating potential shared pathogenic mechanisms. This study aimed to delineate the molecular and cellular connections between DR and PD, with a particular focus on their convergent neuroimmune and vascular pathways. Methods: We integrated single-cell RNA sequencing (scRNA-seq) datasets derived from proliferative DR (PDR) retinal fibrovascular membranes and PD brain tissues. Cell-type-associated transcriptional features were identified within each dataset, and corresponding cell populations were compared to identify candidate overlapping molecular features. CellChat was used to infer potential ligand–receptor interactions between cell populations. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were performed to explore associated biological pathways and transcriptional programs. Results: A2M, NRP1, and ETS2 were identified as candidate shared transcriptional features in corresponding microglial and endothelial cell populations across the PDR and PD datasets. CellChat analysis predicted an ITGB2–ICAM1 (integrin beta-2-Intercellular Adhesion Molecule 1) ligand–receptor interaction in both datasets, although the predicted sender–receiver relationships differed according to tissue context. GSEA and GSVA identified overlapping inflammatory, apoptotic, hypoxia-related, and epithelial–mesenchymal transition-associated transcriptional programs across the analyzed datasets. These findings suggest potentially convergent immune–vascular and inflammatory features between PDR and PD. Conclusions: This exploratory single-cell analysis identified candidate cell-type-associated transcriptional features and potential cell–cell communication patterns shared between PDR and PD. The predicted ITGB2–ICAM1 interaction provides a hypothesis for further investigation of immune–vascular communication. Full article

Leucine-rich repeat kinase 2 (LRRK2) has emerged as a central molecular node linking genetic risk, membrane trafficking, lysosomal homeostasis, and immune signalling in Parkinson’s disease (PD). Rather than functioning as a conventional protein kinase, LRRK2 operates as a conformationally regulated, Rab-directed signalling machine whose activity is governed by long-range interdomain communication, membrane recruitment, and cooperative interactions with small GTPases. Converging advances in cryo-electron microscopy, quantitative phosphoproteomics, and human genetics indicate that pathogenic mutations, lysosomal stress, and pharmacological inhibitors do not simply alter catalytic output, but reshape the conformational landscape of LRRK2, biasing it toward distinct structural states with divergent cellular consequences. A defining feature of this system is the selective phosphorylation of Rab GTPases at low stoichiometry—most prominently Rab8 and Rab10—yet with disproportionate functional impact on vesicle trafficking, ciliogenesis, autophagy, and organelle positioning. The identification of Rab-directed phosphatases, particularly PPM1H, further establishes that LRRK2 signalling is governed by a dynamically balanced kinase–phosphatase circuit operating in space and time. These observations, together with emerging evidence linking LRRK2 activation to lysosomal damage and immune pathways, support a unifying hypothesis: PD-associated LRRK2 dysfunction arises from maladaptive stabilization of specific conformational and spatial states within a membrane-responsive signalling network, leading to persistent misregulation of Rab-dependent trafficking and organelle homeostasis, rather than from kinase hyperactivity alone. In this review, we integrate structural, biochemical, and cellular evidence to advance this framework and discuss its implications for disease mechanisms and therapy. We highlight key unresolved challenges—including conformation-selective drug targeting, spatial control of Rab phosphorylation, and context-dependent immune–neuronal crosstalk—and propose that restoring physiological regulation of LRRK2, rather than simply inhibiting its activity, will be essential for achieving mechanism-based disease modification in Parkinson’s disease. Full article