Hydroxysafflor yellow A ameliorates depression-like behavior in Parkinson's disease mice.

Depression is a common non-motor symptom of Parkinson's disease. Previous studies demonstrated that hydroxysafflor yellow A had properties of improving motor symptoms of Parkinson's disease. The effect of hydroxysafflor yellow A on depression in Parkinson's disease mice is investigated in this study. To induce Parkinson's disease model, male Swiss mice were exposed to rotenone (30 mg/kg) for 6 weeks. The chronic unpredictable mild stress was employed to induce depression from week 3 to week 6. Sucrose preference, tail suspension, and forced swimming tests were conducted. Golgi and Nissl staining of hippocampus were carried out. The levels of dopamine, 5-hydroxytryptamine and the expression of postsynaptic density protein 95, brain-derived neurotrophic factor in hippocampus were assayed. It showed that HSYA improved the depression-like behaviors of Parkinson's disease mice. Hydroxysafflor yellow A attenuated the injury of nerve and elevated contents of dopamine, 5-hydroxytryptamine in hippocampus. Treatment with hydroxysafflor yellow A also augmented the expression of postsynaptic density protein 95 and brain-derived neurotrophic factor. These findings suggest that hydroxysafflor yellow A ameliorates depression-like behavior in Parkinson's disease mice through regulating the contents of postsynaptic density protein 95 and brain-derived neurotrophic factor, therefore protecting neurons and neuronal dendrites of the hippocampus.

A comparison of quantitative parameters of axial posture and spinal mobility between motor subtypes of Parkinson's disease.

Background and purpose:

Parkinson’s disease (PD) is a heterogeneous neurodegenerative disorder characterized by contradictory clinical outcomes among its several subtypes. The disease can manifest with a tremor-dominant (TD) or a non-tremor-dominant (NTD) phenotype. Although the TD subtype may show a better prognosis, there is limited information on the phenotypic differences regarding the level of axial symptoms. For this reason, in this study it was aimed to make a quantitative comparison of axial posture and spinal mobility between PD with TD and NTD. 

This case-control study was conducted on 94 patients with diagnosed PD. A group diagnosis approach was used in the study, such that the diagnosis of each patient was confirmed, and they were assig-ned to TD and NTD groups by a neurologist expert on movement disorders. Of the patients with PD, 61 were in the TD group, and 33 were in the NTD group. Spinal mouse was used to measure spinal posture and spinal mobility in both sagittal and frontal planes. 

Two groups of 61 patients (25 male + 36 female) with TD-PD (mean age: 64.49±10.37 years) and 33 patients (20 male +13 female) with NTD-PD (mean age: 63.45±9.11 years) were enrolled in the study. There were no significant differences bet­ween the patients with TD and NTD in terms of sagittal and frontal postures (p>0.05). In addition to this, anterior trunk tilt was found to significantly increase as the disease stage advanced in both groups. While the greatest anterior trunk tilt change in the TD-PD group was observed in the 3rd stage, NTD-PD group was in the 2.5th stage. Aside from this, the out­comes of the spinal mobility measurements in the frontal and sagittal planes were similar between the groups (p>0.05).

It is widely acknowledged that many clinical aspects of the TD and NTD forms of PD differ; however, in our study, it was observed that there may be no difference in the axial symptoms of the patients with PD in terms of classification according to tremor dominance.

Study on the relationship between peripheral nerve fiber types and levodopa usage in Parkinson's disease.

Background and purpose:

The aim of this study is to comprehensively determine the types of affected fibers in Parkinson’s disease (PD) patients by employing nerve conduction studies (NCS), sympathetic skin response (SSR) examinations, and current perception threshold (CPT) testing and to analyze the correlation between levodopa use and nerve involvement.

This retrospective study included 36 clinically diagnosed PD patients who were recruited between January 2018 and April 2019. All patients underwent NCS, SSR testing, and CPT sensory examinations. Additionally, the PD patients were assessed for disease staging using the Hoehn and Yahr (H-Y) scale. 

Fifteen patients were included in the tremor-dominant subtype, ten patients in the rigid-dominant subtype, and eleven patients in the mixed subtype. Eleven patients were using levodopa, while twenty-five patients had never used any anti-Parkinson’s medication. Ten patients (28%) showed abnormal sympathetic skin responses (SSR). The CPT examination revealed sensory abnormalities in twenty-four patients (67%), with eighteen patients (75%) experiencing sensory hypersensitivity and six patients (25%) experiencing sensory hypoesthesia. Twelve patients (33%) had normal CPT results. Among the patients with abnormal CPT findings, seven cases (29%) involved large myelinated fiber damage, twenty-two cases (92%) involved small myelinated fiber damage, and nineteen cases (79%) involved unmyelinated fiber damage. The rate of sensory abnormalities was 64% (7/11) in the levodopa group and 68% (17/25) in the non-levodopa group, with no statistically significant difference between the two groups. 

The incidence of abnormal CPT findings in PD patients was higher than that of abnormal SSR responses, suggesting that nerve fiber damage primarily affects small fiber nerves (SFN).

Brain Targeting Nanomedicines: Pitfalls and Promise.

Brain diseases are the most devastating problem among the world's increasingly aging population, and the number of patients with neurological diseases is expected to increase in the future. Although methods for delivering drugs to the brain have advanced significantly, none of these approaches provide satisfactory results for the treatment of brain diseases. This remains a challenge due to the unique anatomy and physiology of the brain, including tight regulation and limited access of substances across the blood-brain barrier. Nanoparticles are considered an ideal drug delivery system to hard-to-reach organs such as the brain. The development of new drugs and new nanomaterial-based brain treatments has opened various opportunities for scientists to develop brain-specific delivery systems that could improve treatment outcomes for patients with brain disorders such as Alzheimer's disease, Parkinson's disease, stroke and brain tumors. In this review, we discuss noteworthy literature that examines recent developments in brain-targeted nanomedicines used in the treatment of neurological diseases.

Regional Burden of Enlarged Perivascular Spaces and Cognition and Neuropsychiatric Symptoms in Drug-Naive Patients With Parkinson Disease.

BACKGROUND AND OBJECTIVES: Although the potential role of enlarged perivascular spaces (EPVSs) in Parkinson disease (PD) is increasingly recognized, whether EPVSs located in different anatomical regions exert differential effects on clinical manifestation remains uncertain. We investigated the regional EPVS burden and its association with cognition and neuropsychiatric symptoms (NPSs) in newly diagnosed PD population. METHODS: In this retrospective, cross-sectional study, EPVS in the temporal lobe (T-EPVS), centrum semiovale (CS-EPVS), and basal ganglia (BG-EPVS) were visually rated in drug-naive patients with PD who underwent magnetic resonance imaging, dopamine transporter (DAT) scans, neuropsychological assessments, and Neuropsychiatric Inventory Questionnaire at baseline. Cognitive performance, NPS burden, vascular risk factors, small vessel disease (SVD) imaging markers, and DAT availability were compared across groups dichotomized by their regional EPVS burden (cutoff for high-degree vs low-degree: >10 for T-EPVS/BG-EPVS and >20 for CS-EPVS). RESULTS: A total of 480 patients with PD (123 without cognitive impairment, 291 with mild cognitive impairment, and 66 with dementia) were included. The proportion of high-degree T-EPVS (p for trend <0.001) and BG-EPVS (p for trend = 0.001) exhibited an increasing trend across the cognitive spectrum, corresponding to worsening cognition. Compared with the low-degree group, the high-degree BG-EPVS group showed higher SVD burden (moderate-to-severe white matter hyperintensity [14.8% vs 40.5%, p < 0.001], lacune [10.3% vs 30.7%, p < 0.001], and cerebral microbleeds [8.1% vs 22.2%, p < 0.001]), greater atrophy in cortical gray matter (40.73% ± 1.09% vs 39.96% ± 1.20% of intracranial volume, p < 0.001), and lower cognitive performance (in language [-0.22 ± 1.18 vs -0.53 ± 1.29, p = 0.013], and visual memory domains [-0.24 ± 0.97 vs -0.61 ± 0.96, p = 0.009]). The high-degree T-EPVS group presented with greater NPS burden in decreased motivation (0.61 ± 1.78 vs 1.35 ± 2.36, p = 0.007), affective dysregulation (0.88 ± 2.13 vs 2.36 ± 3.53, p < 0.001), and impulse dyscontrol (0.43 ± 1.67 vs 1.74 ± 4.29, p < 0.001), compared with the low-degree T-EPVS group. Meanwhile, the burden of CS-EPVS did not reveal any differences in cognition or NPS. DISCUSSION: BG-EPVS and T-EPVS seem to exert differential effects on cognition and NPS in patients with PD. Investigating the EPVS profile in distinct anatomical regions may be useful in disentangling the heterogeneity within PD.

Health Care Needs of Individuals with Parkinson's Disease Living in Eastern North Carolina: Insights for Multidisciplinary Care and Telemedicine.

Parkinson's disease (PD) is a complex condition, and individuals living in rural areas often face challenges accessing the specialized care they require. To better understand the specific healthcare needs of individuals with PD in Eastern North Carolina (ENC), the present study investigated three key areas: access to a multidisciplinary care team, access to PD-specific resources, and access to resources for establishing telemedicine services. Participants were recruited through email invitations to Parkinson's Foundation members and the distribution of postcards in the region, and 106 individuals with PD in ENC completed the online survey. Only 28.3% of respondents reported access to an interdisciplinary care team, with approximately 50% stating that their healthcare provider had not informed them of the availability of such a team. Nevertheless, the quality of care received was generally perceived as high, and 41.5% of participants were part of a PD support group. Approximately half of the respondents expressed a willingness to have telemedicine appointments with a movement disorder specialist. These findings offer valuable insights for healthcare providers and policymakers in rural areas to better understand the needs of people with PD. Several strategies, including community building and increased access to telemedicine, are recommended to address these needs.

Group-based exercise for Parkinson's: a qualitative study of participants and partners' perceptions of an exercise class delivered through a community-university collaboration.

BACKGROUND: Community-based exercise programmes (CBEPs) offer a practical and viable approach to providing people with Parkinson's disease (PwP) the opportunity to exercise as an ancillary therapeutic benefit to pharmacological management. This study explores the perceptions of exercising participants (PwP) and non-participating partners involved in an exercise class delivered through a community-university partnership. METHODS: Two separate focus group discussions were conducted: one with class participants (PwP: n = 7, H&Y scale I to III), and the other with non-participating partners of PwP (n = 4). RESULTS: Thematic analysis of the data identified that a range of physical, psychological and social factors were perceived to influence engagement: (1) actively taking control, (2) exercise is medicine for the mind and body, and (3) a community working together to promote exercise for parkinson's. Participants and partners felt that the support from the group, including the instructors and student volunteers, empowered and supported PwP to proactively self-manage their health, enjoy exercise in an inclusive group setting, and develop strong social connections with others in the local Parkinson's community. Support to exercise from healthcare professionals was identified as both an enabler and barrier to participation. CONCLUSIONS: This study underscores the significance of a community-university partnership as a complementary therapeutic approach for PwP. It also provides critical reflections on its sustainability, including implications for how exercise is considered as medicine for PwP. Additionally, it offers practical recommendations to galvanise community participation and provide inclusive and viable exercise opportunities for PwP.

Cross-Sectional and Longitudinal Association of Clinical and Neurocognitive Factors With Apathy in Patients With Parkinson Disease.

BACKGROUND AND OBJECTIVES: A robust understanding of the natural history of apathy in Parkinson disease (PD) is foundational for developing effective clinical management tools. However, large longitudinal studies are lacking while the literature is inconsistent about even cross-sectional associations. We aimed to determine the longitudinal predictors of apathy development in a large cohort of people with PD and its cross-sectional associations and trajectories over time, using sophisticated Bayesian modeling techniques. METHODS: People with PD followed up in the longitudinal New Zealand Parkinson's progression project were included. Apathy was defined using the neuropsychiatric inventory subscale ≥4, and analyses were also repeated using a less stringent cutoff of ≥1. Both MoCA and comprehensive neuropsychological testing were used as appropriate to the model. Depression was assessed using the hospital anxiety and depression scale. Cross-sectional Bayesian regressions were conducted, and a multistate predictive model was used to identify factors that predict the initial onset of apathy in nonapathetic PD, while also accounting for the competing risk of death. The relationship between apathy presence and mortality was also investigated. RESULTS: Three hundred forty-six people with PD followed up for up to 14 years across a total of 1,392 sessions were included. Apathy occurrence did not vary significantly across the disease course (disease duration odds ratio [OR] = 0.55, [95% CI 0.28-1.12], affecting approximately 11% or 22% of people at any time depending on the NPI cutoff used. Its presence was associated with a significantly higher risk of death after controlling for all other factors (hazard ratio [HR] = 2.92 [1.50-5.66]). Lower cognition, higher depression levels, and greater motor severity predicted apathy development in those without motivational deficits (HR [cognition] = 0.66 [0.48-0.90], HR [depression] = 1.45 [1.04-2.02], HR [motor severity] = 1.37 [1.01-1.86]). Cognition and depression were also associated with apathy cross-sectionally, along with male sex and possibly lower dopaminergic therapy level, but apathy still occurred across the full spectrum of each variable (OR [cognition] = 0.58 [0.44-0.76], OR [depression] = 1.43 [1.04-1.97], OR [female sex] = 0.45 [0.22-0.92], and OR [levodopa equivalent dose] = 0.78 [0.59-1.04]. DISCUSSION: Apathy occurs across the PD time course and is associated with higher mortality. Depressive symptoms and cognitive impairment in particular predict its future development in those with normal motivation.

Treatment of Parkinson's disease by deep brain stimulation: a bibliometric analysis.

BACKGROUND: For more than 30 years, deep brain stimulation (DBS) has been a therapeutic tool for Parkinson's disease (PD) treatment. DBS can ameliorate several motor and non-motor symptoms and improve the patients' quality of life. OBJECTIVES: To analyze the global scientific production of original and review articles on Parkinson's disease treatment using deep brain stimulation. DESIGN AND SETTING: Descriptive, bibliometric study with a quantitative approach. METHOD: The research protocol was conducted in March 2023 using the Web of Science database. Six hundred eighty-four articles were included in the analysis. Data were imported into RStudio Desktop Software, linked to R Software. The Bibliometrix R package, its Biblioshiny web interface, and VOSviewer software were used for the analysis. RESULTS: The international production began in 1998. Movement Disorders is the journal with the largest number of published articles and the most cited. Michael Okun and Andres Lozano are the authors who produced the most in this area. The University of Florida is the most active affiliated institution in Brazil. The United States has the largest number of collaborations and is mainly published by local researchers. In contrast, countries such as the United Kingdom and Canada have a high number of multi-country publications. The 15 most cited studies predominantly investigated subthalamic nucleus stimulation. CONCLUSION: DBS for Parkinson's disease is a relatively novel therapeutic approach, with studies that have expanded over the last twenty-five years. Most scientific production was quantitative and restricted to specialized journals. The United States, Europe, and China held the most articles.

Efectos sobre los procesos cognitivos del entrenamiento basado en doble tarea en personas con enfermedad de Parkinson: una revisión sistemática / Effects on cognitive processes of dual-task training in people with Parkinson’s disease: a systematic review

Introducción: La doble tarea es una intervención no farmacológica en personas con condiciones neurodegenerativas, utilizada en la enfermedad de Parkinson (EP), principalmente para favorecer el desempeño motor. El objetivo de esta revisión es reunir la evidencia actual sobre cómo el entrenamiento de doble tarea afecta a los procesos cognitivos en personas que presenten EP. Material y métodos. Se desarrolló una revisión sistemática, aplicando las directrices de PRISMA, incluyendo artículos obtenidos en las bases de datos de PubMed, Web of Science, Science Direct y Springer Link. La calidad metodológica se evaluó mediante PEDro y ROBINS-I. Resultados: Doce artículos cumplieron con los criterios de inclusión y exclusión: nueve de ellos corresponden a ensayos controlados aleatorizados y los tres restantes fueron estudios no aleatorizados. Se identificaron mejoras en la atención y las funciones ejecutivas, aunque la diversidad en enfoques y duración dificulta llegar a conclusiones definitivas. Conclusiones: Es crucial expandir la investigación, estandarizando los programas de intervención. Del mismo modo, es importante llevar a cabo estudios longitudinales y controlados aleatorizados en muestras representativas que permitan llegar a conclusiones aplicables a otros contextos.(AU)

Introduction: Dual-tasking is a non-pharmacological intervention in people with neurodegenerative conditions, and is used in Parkinson’s disease (PD), primarily to enhance motor performance. The aim of this review is to compile the current evidence on how dual-task training affects cognitive processes in people with PD. Material and methods: A systematic review was undertaken, applying PRISMA guidelines, which included articles obtained from the PubMed, Web of Science, Science Direct and Springer Link databases. Methodological quality was assessed using PEDro and ROBINS-I. Results: Twelve articles met the inclusion and exclusion criteria: nine of them were randomized controlled trials, and the remaining three were non-randomized studies. Improvements in attention and executive functions were identified, although the diversity of approaches and duration means that reaching definitive conclusions is difficult. Conclusions: Increased research and standardized intervention programmes are essential. Longitudinal and randomized controlled studies in representative samples which provide conclusions that are applicable to other contexts are also important.(AU)

Predict the prevalence and incidence of Parkinson's disease using fractal interpolation-LSTM model.

The investigation of the prediction of disease population is a noticeable exploration topic in the field of sciences. As a type of neurological disease, the incidence and prevalence of Parkinson's disease are still difficult to accurately study. In this paper, a method is proposed to forecast the number of incident cases (NumIn), incidence rate (InRa), the number of prevalent cases (NumPr), and prevalence rate (PrRa) of Parkinson's disease in ten countries selected. Using past data on the incidence rate, the number of prevalent cases, and the prevalence rate from 1990 to 2019, three types of fractal interpolations with different fractal dimensions are constructed for reconstructing the past data, where the vertical scaling factors are determined by the method proposed in this article. Then, the Long Short-Term Memory (LSTM) model is employed to forecast the values of NumIn, InRa, NumPr, and PrRa with Parkinson's disease in 2020. Meanwhile, the autoregressive integrated moving average model is used to predict the values compared with the LSTM model. The evaluation metrics employed for error calculation include the root mean square error and the coefficient of determination (R2). According to the proposed optimal criteria, the best predicted results are the average of three types of prediction values based on the LSTM model by analyzing and comparing eight predicted results.

Non-HLA angiotensin-type-1 receptor autoantibodies mediate the long-term loss of grafted neurons in Parkinson's disease models.

BACKGROUND: Clinical trials have provided evidence that transplants of dopaminergic precursors, which may be replaced by new in vitro stem cell sources, can integrate into the host tissue, and alleviate motor symptoms in Parkinson´s disease (PD). In some patients, deterioration of graft function occurred several months after observing a graft-derived functional improvement. Rejection of peripheral organs was initially related to HLA-specific antibodies. However, the role of non-HLA antibodies is now considered also relevant for rejection. Angiotensin-II type-1 receptor autoantibodies (AT1-AA) act as agonists of the AT1 receptors. AT1-AA are the non-HLA antibodies most widely associated with graft dysfunction or rejection after transplantation of different solid organs and hematopoietic stem cells. However, it is not known about the presence and possible functional effects of AT1-AA in dopaminergic grafts, and the effects of treatment with AT1 receptor blockers (ARBs) such as candesartan on graft survival. METHODS: In a 6-hydroxydopamine PD rat model, we studied the short-term (10 days)- and long-term (3 months) effects of chronic treatment with the ARB candesartan on survival of grafted dopaminergic neurons and microglial graft infiltration, as well as the effects of dopaminergic denervation and grafting on serum and CSF AT1-AA levels. The expression of AT1 receptors in grafted neurons was determined by laser capture microdissection. RESULTS: At the early period post-grafting, the number of grafted dopaminergic neurons that survived was not significantly different between treated and untreated hosts (i.e., control rats and rats treated with candesartan), probably because, just after grafting, other deleterious factors are predominant for dopaminergic cell death, such as mechanical trauma, lack of growth factors/nutrients and ischemia. However, several months post-grafting, we observed a significantly higher number of surviving dopaminergic neurons and a higher density of striatal dopaminergic terminals in the candesartan-treated group. For several months, grafted rats showed blood and cerebrospinal fluid levels of AT1-AA higher than normal controls, and also higher AT1-AA levels than non-grafted parkinsonian rats. CONCLUSIONS: The results suggest the use of ARBs such as candesartan in PD patients, particularly before and after dopaminergic grafts, and the need to monitor AT1-AA levels in PD patients, particularly in those candidates for dopaminergic grafting.

Letter to editor: gender gap in deep brain stimulation for Parkinson's disease: preliminary results of a retrospective study.

This letter addresses important considerations for enhancing the research on the gender gap in deep brain stimulation (DBS) for Parkinson's disease. While acknowledging the commendable efforts of the study's authors, we highlight several areas that warrant further attention to maximize the research's yield and applicability. Specifically, we emphasize the need for a more diverse cohort to enhance the generalizability of findings, inclusion of a control group for comprehensive evaluation, utilization of additional assessment tools to mitigate bias, incorporation of qualitative data for a holistic understanding, and evaluation of long-term outcomes beyond short follow-up durations. Addressing these considerations would strengthen the validity, applicability, and impact of research findings in this crucial area of study.

Serum urate levels and neurodegenerative outcomes: a prospective cohort study and mendelian randomization analysis of the UK Biobank.

BACKGROUND: Previous studies on the associations between serum urate levels and neurodegenerative outcomes have yielded inconclusive results, and the causality remains unclear. This study aimed to investigate whether urate levels are associated with the risks of Alzheimer's disease and related dementias (ADRD), Parkinson's disease (PD), and neurodegenerative deaths. METHODS: This prospective study included 382,182 participants (45.7% men) from the UK Biobank cohort. Cox proportional hazards models were used to assess the associations between urate levels and risk of neurodegenerative outcomes. In the Mendelian randomization (MR) analysis, urate-related single-nucleotide polymorphisms were identified through a genome-wide association study. Both linear and non-linear MR approaches were utilized to investigate the potential causal associations. RESULTS: During a median follow-up period of 12 years, we documented 5,400 ADRD cases, 2,553 PD cases, and 1,531 neurodegenerative deaths. Observational data revealed that a higher urate level was associated with a decreased risk of ADRD (hazard ratio [HR]: 0.93, 95% confidence interval [CI]: 0.90, 0.96), PD (HR: 0.87, 95% CI: 0.82, 0.91), and neurodegenerative death (HR: 0.88, 95% CI: 0.83, 0.94). Negative linear associations between urate levels and neurodegenerative events were observed (all P-values for overall < 0.001 and all P-values for non-linearity > 0.05). However, MR analyses yielded no evidence of either linear or non-linear associations between genetically predicted urate levels and the risk of the aforementioned neurodegenerative events. CONCLUSION: Although the prospective cohort study demonstrated that elevated urate levels were associated with a reduced risk of neurodegenerative outcomes, MR analyses found no evidence of causality.

The Role of Oxygen Homeostasis and the HIF-1 Factor in the Development of Neurodegeneration.

Understanding the molecular underpinnings of neurodegeneration processes is a pressing challenge for medicine and neurobiology. Alzheimer's disease (AD) and Parkinson's disease (PD) represent the most prevalent forms of neurodegeneration. To date, a substantial body of experimental evidence has strongly implicated hypoxia in the pathogenesis of numerous neurological disorders, including AD, PD, and other age-related neurodegenerative conditions. Hypoxia-inducible factor (HIF) is a transcription factor that triggers a cell survival program in conditions of oxygen deprivation. The involvement of HIF-1α in neurodegenerative processes presents a complex and sometimes contradictory picture. This review aims to elucidate the current understanding of the interplay between hypoxia and the development of AD and PD, assess the involvement of HIF-1 in their pathogenesis, and summarize promising therapeutic approaches centered on modulating the activity of the HIF-1 complex.

PRKN-linked familial Parkinson's disease: cellular and molecular mechanisms of disease-linked variants.

Parkinson's disease (PD) is a common and incurable neurodegenerative disorder that arises from the loss of dopaminergic neurons in the substantia nigra and is mainly characterized by progressive loss of motor function. Monogenic familial PD is associated with highly penetrant variants in specific genes, notably the PRKN gene, where homozygous or compound heterozygous loss-of-function variants predominate. PRKN encodes Parkin, an E3 ubiquitin-protein ligase important for protein ubiquitination and mitophagy of damaged mitochondria. Accordingly, Parkin plays a central role in mitochondrial quality control but is itself also subject to a strict protein quality control system that rapidly eliminates certain disease-linked Parkin variants. Here, we summarize the cellular and molecular functions of Parkin, highlighting the various mechanisms by which PRKN gene variants result in loss-of-function. We emphasize the importance of high-throughput assays and computational tools for the clinical classification of PRKN gene variants and how detailed insights into the pathogenic mechanisms of PRKN gene variants may impact the development of personalized therapeutics.

From the Gut to the Brain: Is Microbiota a New Paradigm in Parkinson's Disease Treatment?

Parkinson's disease (PD) is recognized as the second most prevalent primary chronic neurodegenerative disorder of the central nervous system. Clinically, PD is characterized as a movement disorder, exhibiting an incidence and mortality rate that is increasing faster than any other neurological condition. In recent years, there has been a growing interest concerning the role of the gut microbiota in the etiology and pathophysiology of PD. The establishment of a brain-gut microbiota axis is now real, with evidence denoting a bidirectional communication between the brain and the gut microbiota through metabolic, immune, neuronal, and endocrine mechanisms and pathways. Among these, the vagus nerve represents the most direct form of communication between the brain and the gut. Given the potential interactions between bacteria and drugs, it has been observed that the therapies for PD can have an impact on the composition of the microbiota. Therefore, in the scope of the present review, we will discuss the current understanding of gut microbiota on PD and whether this may be a new paradigm for treating this devastating disease.

Neuropathologic Validation and Diagnostic Accuracy of Presynaptic Dopaminergic Imaging in the Diagnosis of Parkinsonism.

BACKGROUND AND OBJECTIVES: Degeneration of the presynaptic nigrostriatal dopaminergic system is one of the main biological features of Parkinson disease (PD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), which can be measured using single-photon emission CT imaging for diagnostic purposes. Despite its widespread use in clinical practice and research, the diagnostic properties of presynaptic nigrostriatal dopaminergic (DAT) imaging in parkinsonism have never been evaluated against the diagnostic gold standard of neuropathology. The aim of this study was to evaluate the diagnostic parameters of DAT imaging compared with pathologic diagnosis in patients with parkinsonism. METHODS: Retrospective cohort study of patients with DAT imaging for the investigation of a clinically uncertain parkinsonism with brain donation between 2010 and 2021 to the Queen Square Brain Bank (London). Patients with DAT imaging for investigation of pure ataxia or dementia syndromes without parkinsonism were excluded. Those with a pathologic diagnosis of PD, MSA, PSP, or CBD were considered presynaptic dopaminergic parkinsonism, and other pathologies were considered postsynaptic for the analysis. DAT imaging was performed in routine clinical practice and visually classified by hospital nuclear medicine specialists as normal or abnormal. The results were correlated with neuropathologic diagnosis to calculate diagnostic accuracy parameters for the diagnosis of presynaptic dopaminergic parkinsonism. RESULTS: All of 47 patients with PD, 41 of 42 with MSA, 68 of 73 with PSP, and 6 of 10 with CBD (sensitivity 100%, 97.6%, 93.2%, and 60%, respectively) had abnormal presynaptic dopaminergic imaging. Eight of 17 patients with presumed postsynaptic parkinsonism had abnormal scans (specificity 52.9%). DISCUSSION: DAT imaging has very high sensitivity and negative predictive value for the diagnosis of presynaptic dopaminergic parkinsonism, particularly for PD. However, patients with CBD, and to a lesser extent PSP (of various phenotypes) and MSA (with predominant ataxia), can show normal DAT imaging. A range of other neurodegenerative disorders may have abnormal DAT scans with low specificity in the differential diagnosis of parkinsonism. DAT imaging is a useful diagnostic tool in the differential diagnosis of parkinsonism, although clinicians should be aware of its diagnostic properties and limitations. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that DAT imaging does not accurately distinguish between presynaptic dopaminergic parkinsonism and non-presynaptic dopaminergic parkinsonism.