Vascular disease and vascular risk factors in relation to motor features and cognition in early Parkinson's disease

The Contribution of Type 2 Diabetes to Parkinson's Disease Aetiology

Type 2 diabetes (T2D) and Parkinson's disease (PD) are chronic disorders that have a significant health impact on a global scale. Epidemiological, preclinical, and clinical research underpins the assumption that insulin resistance and chronic inflammation contribute to the overlapping aetiologies of T2D and PD. This narrative review summarises the recent evidence on the contribution of T2D to the initiation and progression of PD brain pathology. It also briefly discusses the rationale and potential of alternative pharmacological interventions for PD treatment.

Proteomics of mouse brain endothelium uncovers dysregulation of vesicular transport pathways during aging

Age-related decline in brain endothelial cell (BEC) function contributes critically to neurological disease. Comprehensive atlases of the BEC transcriptome have become available, but results from proteomic profiling are lacking. To gain insights into endothelial pathways affected by aging, we developed a magnetic-activated cell sorting-based mouse BEC enrichment protocol compatible with proteomics and resolved the profiles of protein abundance changes during aging. Unsupervised cluster analysis revealed a segregation of age-related protein dynamics with biological functions, including a downregulation of vesicle-mediated transport. We found a dysregulation of key regulators of endocytosis and receptor recycling (most prominently Arf6), macropinocytosis and lysosomal degradation. In gene deletion and overexpression experiments, Arf6 affected endocytosis pathways in endothelial cells. Our approach uncovered changes not picked up by transcriptomic studies, such as accumulation of vesicle cargo and receptor ligands, including Apoe. Proteomic analysis of BECs from Apoe-deficient mice revealed a signature of accelerated aging. Our findings provide a resource for analysing BEC function during aging.

Molecular mechanism of cognitive impairment associated with Parkinson's disease: A stroke perspective

Parkinson's disease (PD) is a common neurological illness that causes several motor and non-motor symptoms, most characteristically limb tremors and bradykinesia. PD is a slowly worsening disease that arises due to progressive neurodegeneration of specific areas of the brain, especially the substantia nigra of the midbrain. Even though PD has continuously been linked to a higher mortality risk in numerous epidemiologic studies, there have been significant discoveries regarding the connection between PD and stroke. The incidence of strokes such as cerebral infarction and hemorrhage is substantially associated with the development of PD. Moreover, cognitive impairments, primarily dementia, have been associated with stroke and PD. However, the underlying molecular mechanism of this phenomenon is still obscure. This concise review focuses on the relationship between stroke and PD, emphasizing the molecular mechanism of cognition deficit and memory loss evident in PD and stroke. Furthermore, we are also highlighting some potential drug molecules that can target both PD and stroke.

Prevalence of Concomitant Pathologies in Parkinson's Disease: Implications for Prognosis, Diagnosis, and Insights into Common Pathogenic Mechanisms

Pathologies characteristic of Alzheimer's disease (i.e., hyperphosphorylated tau and amyloid-β (Aβ) plaques), cardiovascular disease, and limbic predominant TDP-43 encephalopathy (LATE) often co-exist in patients with Parkinson's disease (PD), in addition to Lewy body pathology (α-synuclein). Numerous studies point to a putative synergistic relationship between hyperphosphorylation tau, Aβ, cardiovascular lesions, and TDP-43 with α-synuclein, which may alter the stereotypical pattern of pathological progression and accelerate cognitive decline. Here we discuss the prevalence and relationships between common concomitant pathologies observed in PD. In addition, we highlight shared genetic risk factors and developing biomarkers that may provide better diagnostic accuracy for patients with PD that have co-existing pathologies. The tremendous heterogeneity observed across the PD spectrum is most likely caused by the complex interplay between pathogenic, genetic, and environmental factors, and increasing our understanding of how these relate to idiopathic PD will drive research into finding accurate diagnostic tools and disease modifying therapies.

Updates on brain regions and neuronal circuits of movement disorders in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disease with a global burden that affects more often in the elderly. The basal ganglia (BG) is believed to account for movement disorders in PD. More recently, new findings in the original regions in BG involved in motor control, as well as the new circuits or new nucleuses previously not specifically considered were explored. In the present review, we provide up-to-date information related to movement disorders and modulations in PD, especially from the perspectives of brain regions and neuronal circuits. Meanwhile, there are updates in deep brain stimulation (DBS) and other factors for the motor improvement in PD. Comprehensive understandings of brain regions and neuronal circuits involved in motor control could benefit the development of novel therapeutical strategies in PD.

Subthalamic deep brain stimulation improves vascular endothelial function in Parkinson's disease

OBJECTIVES

Vascular health (white matter change, vascular risk factor, angiogenesis, microvascular alteration) is associated with clinical progression or levodopa-induced dyskinesia in PD. Vascular endothelial function is known to reflect the earliest vascular change. While DBS can improve motor and non-motor symptoms, the effect of DBS on vascular endothelial function is unknown. Thus, we aimed to investigate whether DBS surgery could impact vascular endothelial function in PD.

METHOD

A total of 20 PD patients were recruited. Vascular endothelial function was evaluated with flow-mediated dilation (FMD). FMD was investigated before and after one year of DBS surgery.

RESULTS

FMD improved (6.01 ± 1.58 to 6.84 ± 1.57, p = 0.027). While the level of homocysteine slightly decreased (13.8 ± 4.1 to 13.0 ± 3.2, p = 0.05), there was no significant correlation between FMD changes and homocysteine levels (r = 0.42, p = 0.065). FMD change was associated with baseline age (r = -0.59, p = 0.006) but not with disease duration (p = 0.73), baseline UPDRS III (p = 0.81), change of UPDRS III and dyskinesia, and LEDD change (p = 0.94). Multivariate linear regression analysis revealed that only age (B = -0.139; p = 0.024) was significantly and inversely correlated with the change of FMD.

CONCLUSIONS

We found that STN-DBS improves vascular endothelial function in PD. Further studies are needed to clarify the exact pathogenesis and clinical implication of beneficial effects on vascular endothelial dysfunction in PD.

Targeting neuroendocrine abnormalities in Parkinson's disease with exercise

Parkinson's Disease (PD) is a prevalent and complex age-related neurodegenerative condition for which there are no disease-modifying treatments currently available. The pathophysiological process underlying PD remains incompletely understood but increasing evidence points to multiple system dysfunction. Interestingly, the past decade has produced evidence that exercise not only reduces signs and symptoms of PD but is also potentially neuroprotective. Characterizing the mechanistic pathways that are triggered by exercise and lead to positive outcomes will improve understanding of how to counter disease progression and symptomatology. In this review, we highlight how exercise regulates the neuroendocrine system, whose primary role is to respond to stress, maintain homeostasis and improve resilience to aging. We focus on a group of hormones - cortisol, melatonin, insulin, klotho, and vitamin D - that have been shown to associate with various non-motor symptoms of PD, such as mood, cognition, and sleep/circadian rhythm disorder. These hormones may represent important biomarkers to track in clinical trials evaluating effects of exercise in PD with the aim of providing evidence that patients can exert some behavioral-induced control over their disease.

Cerebral Microvascular Injury Induced by Lag3-Dependent α-Synuclein Fibril Endocytosis Exacerbates Cognitive Impairment in a Mouse Model of α-Synucleinopathies

The pathological accumulation of α-synuclein (α-Syn) and the transmission of misfolded α-Syn underlie α-synucleinopathies. Increased plasma α-Syn levels are associated with cognitive impairment in Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies, but it is still unknown whether the cognitive deficits in α-synucleinopathies have a common vascular pathological origin. Here, it is reported that combined injection of α-Syn preformed fibrils (PFFs) in the unilateral substantia nigra pars compacta, hippocampus, and cerebral cortex results in impaired spatial learning and memory abilities at 6 months post-injection and that this cognitive decline is related to cerebral microvascular injury. Moreover, insoluble α-Syn inclusions are found to form in primary mouse brain microvascular endothelial cells (BMVECs) through lymphocyte-activation gene 3 (Lag3)-dependent α-Syn PFFs endocytosis, causing poly(ADP-ribose)-driven cell death and reducing the expression of tight junction proteins in BMVECs. Knockout of Lag3 in vitro prevents α-Syn PFFs from entering BMVECs, thereby reducing the abovementioned response induced by α-Syn PFFs. Deletion of endothelial cell-specific Lag3 in vivo reverses the negative effects of α-Syn PFFs on cerebral microvessels and cognitive function. In short, this study reveals the effectiveness of targeting Lag3 to block the spread of α-Syn fibrils to endothelial cells in order to improve cognition.

Regional white matter hyperintensity volume in Parkinson's disease and associations with the motor signs

OBJECTIVE

To determine whether white matter hyperintensity (WMH) volumes in specific regions are associated with Parkinson's disease (PD) compared to non-PD controls, and to assess their impact on motor signs through cross-sectional and longitudinal analyses.

METHODS

A total of 50 PD participants and 47 age- and gender-matched controls were enrolled. All PD participants were followed up for at least 2 years. To detect regions of greater WMH in the PD, the WMH volume of each region was compared with the corresponding region in the control group. Linear regression and linear mixed effects models were respectively used for cross-sectional and longitudinal analyses of the impact of increases in WMH volume on motor signs.

RESULTS

The PD group had greater WMH volume in the occipital region compared with the control group. Cross-sectional analyses only detected a significant correlation between occipital WMH volume and motor function in PD. Occipital WMH volume positively correlated with the severity of tremor, and gait and posture impairments, in the PD group. During the follow-up period, the participants' motor signs progressed and the WMH volumes remained stable, no longitudinal association was detected between them. The baseline occipital WMH volume cannot predict the progression of signs after adjustment for baseline disease duration and the presence of vascular risk factors.

INTERPRETATION

PD participants in this study were characterized by greater WMH at the occipital region, and greater occipital WMH volume had cross-sectional associations with worse motor signs, while its longitudinal impact on motor signs progression was limited.

Altered Cerebral Vasoreactivity on Transcranial Color-Coded Sonography Related to Akinetic-Rigid Phenotype of Parkinson's Disease: Interim Analysis of a Cross-Sectional Study

BACKGROUND

A correlation between worse functional outcomes in Parkinson's disease (PD) patients with cerebrovascular disease (CVD) or the Akinetic-rigid phenotype has been argued in recent studies. We aimed to evaluate the association of cerebral hemodynamics impairments, assessed by Transcranial Color-coded Doppler sonography (TCCS), on PD patients with different phenotypes of the disease and with risk factors for CVD.

METHODOLOGY

Idiopathic PD patients (n = 51) were divided into motor subtypes: Akinetic-rigid (AR) (n = 27) and Tremor-dominant (TD) (n = 24) and into two groups regarding vascular risk factors: when ≥2 were present (PDvasc) (n = 18) and <2 (PDnvasc) (n = 33). In a parallel analysis, the Fazekas scale on brain magnetic resonance imaging (MRI) was applied to a sample to assess the degree of leukoaraiosis. TCCS examinations were prospectively performed obtaining middle cerebral artery Mean Flow Velocities (Vm), Resistance Index (RI), and Pulsatility Index (PI). The Breath-Holding Index (BHI) was calculated to assess cerebrovascular reactivity (cVR). Standardized functional scales were administered (UPDRS III and Hoehn&Yahr).

RESULTS

The phenotype groups were similar in age, disease duration and demographic parameters, but there were significantly higher H&Y scores than TD group. cVR was impaired in 66.7% of AR vs. 37.5% of TD. AR group exhibited lower BHI (0.53 ± 0.31 vs. 0.91 ± 0.62; p = 0.000), lower Vm after apnea (44.3 ± 9.0 cm/s vs. 53.4 ± 11.4 cm/s; p = 0.003), higher PI (0.91 ± 0.26 vs. 0.76 ± 0.12; p = 0.000) and RI (0.58 ± 0.11 vs. 0.52 ± 0.06; p = 0.021). PDvasc group showed higher PI (0.98 vs. 0.76; p = 0.001) and higher frequency of altered cVR (72.2% vs. 42.2%; p = 0.004). There was a significant predominance of higher values on Fazekas scale in the PDvasc group. We found no difference between the Fazekas scale when comparing motor subtypes groups but there was a trend toward higher scores in the AR phenotype.

CONCLUSIONS

TCCS, a cost-effective method, displayed impaired cVR in Parkinsonian patients with risk factors for CVD with higher degree of MRI leukoaraiosis. PD patients with the AR disease phenotype also presented impaired cVR on TCCS and greater functional impairment, although with just a trend to higher scores on MRI Fazekas.

Association between diabetes mellitus, prediabetes and risk, disease progression of Parkinson's disease: A systematic review and meta-analysis

Background

Previous studies reported inconsistent results regarding association between diabetes mellitus (DM), prediabetes and risk, disease progression of Parkinson's disease (PD). The meta-analysis was made to investigate association between DM, prediabetes and risk, disease progression of PD.

Methods

Literatures investigating association between DM, prediabetes and risk, disease progression of PD were searched in these databases: PubMed and Web of Science. Included literatures were published before October 2022. STATA 12.0 software was used to compute odds ratios (ORs)/relative risks (RRs) or standard mean differences (SMDs).

Results

DM was associated with a higher risk of PD, compared to non-diabetic participants with a random effects model (OR/RR = 1.23, 95% CI 1.12–1.35, I2 = 90.4%, p &lt; 0.001). PD with DM (PD-DM) was associated with a faster motor progression compared to PD without DM (PD-noDM) with a fixed effects model (RR = 1.85, 95% CI 1.47–2.34, I2 = 47.3%, p = 0.091). However, meta-analysis for comparison in change rate of United Rating Scale (UPDRS) III scores from baseline to follow-up time between PD-DM and PD-noDM reported no difference in motor progression between PD-DM and PD-noDM with a random effects model (SMD = 2.58, 95% CI = −3.11 to 8.27, I2 = 99.9%, p &lt; 0.001). PD-DM was associated with a faster cognitive decline compared to PD-noDM with a fixed effects model (OR/RR = 1.92, 95% CI 1.45–2.55, I2 = 50.3%, p = 0.110).

Conclusions

In conclusion, DM was associated with a higher risk and faster disease decline of PD. More large-scale cohort studies should be adopted to evaluate the association between DM, prediabetes and PD.

Associations of Preexisting Vascular Risk Factors With Outcomes After Traumatic Brain Injury: A TRACK-TBI Study

OBJECTIVE

To evaluate associations of preinjury vascular risk factors with traumatic brain injury (TBI) outcomes.

SETTING

The level 1 trauma center-based T ransforming R esearch a nd C linical K nowledge in TBI (TRACK-TBI) Study.

PARTICIPANTS

A total of 2361 acute TBI patients 18 years or older who presented to the emergency department within 24 hours of head trauma warranting clinical evaluation with a noncontrast head CT between February 26, 2014, and August 8, 2018.

DESIGN

A multicenter prospective cohort study.

MAIN MEASURES

Vascular risk factors (hypertension, diabetes, hyperlipidemia, and smoking) were assessed at baseline by self- or proxy-report and chart review. The primary outcome was the 6-month Glasgow Outcome Scale-Extended TBI version (GOSE-TBI). Secondary 6-month outcomes included the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), the Satisfaction with Life Scale (SWLS), and the 18-item Brief Symptom Inventory Global Severity Index (BSI-18-GSI).

RESULTS

Mean age of participants was 42 years, 31% were women, and 16% were Black. Current smoking was the most common vascular risk factor (29%), followed by hypertension (17%), diabetes (8%), and hyperlipidemia (6%). Smoking was the only risk factor associated with worse scores on all 4 outcome indices. Hypertension and diabetes were associated with worse RPQ scores, and hypertension was associated with worse BSI-18-GSI scores (all P < .05). Compared with individuals with no vascular risk factors, individuals with 1 but not 2 or more vascular risk factors had significantly worse GOSE-TBI and SWLS scores, while a higher burden of vascular risk factors was significantly associated with worse RPQ and BSI-18-GSI scores.

CONCLUSION

Our study found that preinjury vascular risk factors, especially smoking, are associated with worse outcomes after TBI. Aggressive postinjury treatment of vascular risk factors may be a promising strategy to improve TBI outcomes.

Nanozyme-Enabled Treatment of Cardio- and Cerebrovascular Diseases

Cardio- and cerebrovascular diseases are two major vascular-related diseases that lead to death worldwide. Reactive oxygen species (ROS) play a vital role in the occurrence and exacerbation of diseases. Excessive ROS induce cellular context damage and lead to tissue dysfunction. Nanozymes, as emerging enzyme mimics, offer a unique perspective for therapy through multifunctional activities, achieving essential results in the treatment of ROS-related cardio- and cerebrovascular diseases by directly scavenging excess ROS or regulating pathologically related molecules. This review first introduces nanozyme-enabled therapeutic mechanisms at the cellular level. Then, the therapies for several typical cardio- and cerebrovascular diseases with nanozymes are discussed, mainly including cardiovascular diseases, ischemia reperfusion injury, and neurological disorders. Finally, the challenges and outlooks for the application of nanozymes are also presented. This review will provide some instructive perspectives on nanozymes and promote the development of enzyme-mimicking strategies in cardio- and cerebrovascular disease therapy.

Biomarkers: Role and Scope in Neurological Disorders

Neurological disorders pose a great threat to social health and are a major cause for mortality and morbidity. Effective drug development complemented with the improved drug therapy has made considerable progress towards easing symptoms associated with neurological illnesses, yet poor diagnosis and imprecise understanding of these disorders has led to imperfect treatment options. The scenario is complicated by the inability to extrapolate results of cell culture studies and transgenic models to clinical applications which has stagnated the process of improving drug therapy. In this context, the development of biomarkers has been viewed as beneficial to easing various pathological complications. A biomarker is measured and evaluated in order to gauge the physiological process or a pathological progression of a disease and such a marker can also indicate the clinical or pharmacological response to a therapeutic intervention. The development and identification of biomarkers for neurological disorders involves several issues including the complexity of the brain, unresolved discrepant data from experimental and clinical studies, poor clinical diagnostics, lack of functional endpoints, and high cost and complexity of techniques yet research in the area of biomarkers is highly desired. The present work describes existing biomarkers for various neurological disorders, provides support for the idea that biomarker development may ease our understanding underlying pathophysiology of these disorders and help to design and explore therapeutic targets for effective intervention.

Blood Biomarkers in Patients with Parkinson's Disease: A Review in Context of Anesthetic Care

Parkinson's disease (PD) is the second most common inflammatory neurodegenerative disorder after dementia. Preclinical and epidemiological data strongly suggest that chronic neuroinflammation slowly induces neuronal dysfunction. Activated microglia secrete several neurotoxic substances, such as chemokines and proinflammatory cytokines, which may promote blood-brain barrier (BBB) permeabilization. CD4⁺ T cells comprise proinflammatory cells such as T helper (Th) 1 and Th17 cells, as well as anti-inflammatory cells such as Th2 and T regulatory cells (Tregs). Th1 and Th17 cells can be detrimental to dopamine neurons, whereas Th2 and Tregs are neuroprotective. The results of studies on the serum levels of cytokines such as IFN-γ and TNF-α secreted by Th1 T cells, IL-8 and IL-10 secreted by Th2 T cells, and IL-17 secreted by Th17 cells in PD patients are not uniform. In addition, the relationships between serum cytokine levels and motor and non-motor symptoms of PD are controversial. Surgical stress and anesthesia induce inflammatory responses by disturbing the balance between pro- and anti-inflammatory cytokines, which may exacerbate the neuroinflammatory response in PD patients. Here we review studies on blood inflammatory biomarkers in PD patients and discuss the roles of surgery and anesthesia in PD progression.

Type 2 Diabetes and Parkinson's Disease: A Focused Review of Current Concepts

Highly reproducible epidemiological evidence shows that type 2 diabetes (T2D) increases the risk and rate of progression of Parkinson's disease (PD), and crucially, the repurposing of certain antidiabetic medications for the treatment of PD has shown early promise in clinical trials, suggesting that the effects of T2D on PD pathogenesis may be modifiable. The high prevalence of T2D means that a significant proportion of patients with PD may benefit from personalized antidiabetic treatment approaches that also confer neuroprotective benefits. Therefore, there is an immediate need to better understand the mechanistic relation between these conditions and the specific molecular pathways affected by T2D in the brain. Although there is considerable evidence that processes such as insulin signaling, mitochondrial function, autophagy, and inflammation are involved in the pathogenesis of both PD and T2D, the primary aim of this review is to highlight the evidence showing that T2D-associated dysregulation of these pathways occurs not only in the periphery but also in the brain and how this may facilitate neurodegeneration in PD. We also discuss the challenges involved in disentangling the complex relationship between T2D, insulin resistance, and PD, as well as important questions for further research. © 2022 International Parkinson and Movement Disorder Society.

Lacunes may worsen cognition but not motor function in Parkinson's disease

BACKGROUND

As one of the imaging markers of cerebral small vessel disease, lacunes has received little attention. The objective of this study was to investigate the associations of lacunes, cognition and motor function in patients with Parkinson's disease (PD) and whether these associations are independent of other imaging markers.

METHODS

Patients were consecutively included from April 2019 to July 2022 in _{Beijing Rehabilitation Hospital.} All patients underwent brain magnetic resonance imaging scans, clinical scale evaluations, and neuropsychological tests, as well as quantitative evaluation of postural control. To eliminate the possible factors contributing to cognition and motor dysfunction in patients with PD, in particular white matter hyperintensities and enlarged perivascular space in the basal ganglia, multivariate linear regression models were constructed to sort out the effect of lacunes.

RESULTS

Ninety-four patients were included in this study, 56 without lacunes and 38 with lacunes. Patients with lacunes showed shorter disease duration, slower gait speed and spent more time on Trail-Making Test part A (TMT-A) than those without lacunes. The number of lacunes were positively correlated with the time to complete the TMT-A and negatively related to gait speed. Multivariate linear regression models showed that the presence of lacunes was associated with longer TMT-A time after adjusting for potential confounders.

CONCLUSIONS

Lacunes were independently associated with worse visual scanning, attention, and processing speed in patients with PD. In addition, lacunes may accelerate the course of PD. Early treatment of vascular disease provides an alternate way to mitigate some motor and cognitive dysfunction in patients with PD.

White matter hyperintensities burden in the frontal regions is positively correlated to the freezing of gait in Parkinson's disease

Objective

Previous studies have reported that white matter hyperintensities (WMHs) are associated with freezing of gait (FOG), but it is not clear whether their distribution areas have correlations with FOG in Parkinson's disease (PD) and the potential influencing factors about WMHs.

Methods

Two hundred and forty-six patients with PD who underwent brain MRI were included. Participants were divided into PD with FOG (n = 111) and PD without FOG (n = 135) groups. Scheltens score was used to assess the WMHs burden in the areas of deep white matter hyperintensities (DWMHs), periventricular hyperintensities (PVHs), basal ganglia hyperintensities (BGHs), and infratentorial foci of hyperintensities (ITF). Whole brain WMHs volume was evaluated by automatic segmentation. Binary logistic regression was used to evaluate relationships between WMHs and FOG. The common cerebrovascular risk factors that may affect WMHs were evaluated by mediation analysis.

Results

There were no statistical differences between PD with and without FOG groups in whole brain WMHs volume, total Scheltens score, BGHs, and ITF. Binary logistic regression showed that the total scores of DWMHs (OR = 1.094; 95% CI, 1.001, 1.195; p = 0.047), sum scores of PVHs and DWMHs (OR = 1.080; 95% CI, 1.003, 1.164; p = 0.042), especially the DWMHs in frontal (OR = 1.263; 95% CI, 1.060, 1.505 p = 0.009), and PVHs in frontal caps (OR = 2.699; 95% CI, 1.337, 5.450; p = 0.006) were associated with FOG. Age, hypertension, and serum alkaline phosphatase (ALP) are positively correlated with scores of DWMHs in frontal and PVHs in frontal caps.

Conclusion

These results indicate that WMHs distribution areas especially in the frontal of DWMHs and PVHs play a role in PD patients with FOG.

White matter hyperintensity presence, quantity, and location exhibits no association with motor and non-motor manifestations of PD

INTRODUCTION

Nonspecific areas of brain white matter hyperintensity (WMH) are commonly found in the elderly. Some studies have shown that the presence, quantity, and location of WMHs may be associated with the development of cognitive and motor decline in patients with Parkinson's disease (PD), but the results remain controversial. This study aimed to evaluate the relationship of WMH to motor and non-motor symptoms, including dysautonomia and rapid eye movement sleep behavior disorder (RBD), in patients with PD.

METHODS

Brain magnetic resonance images were acquired from 120 patients diagnosed with PD and analyzed for WMH classification and quantification. Motor symptoms were quantified using sub-scores of the Movement Disorder Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS)-III. Dysautonomia was evaluated by autonomic reactivity tests, and polysomnography was used for the diagnosis of RBD.

RESULTS

Age, total value of the MDS-UPDRS-III tremor sub-score, and the presence of dysautonomia were found to be linearly positively associated. Specifically, the duration of PD was positively associated with rigidity, bradykinesia, axial symptoms, prevalence of dysautonomia, and RBD sub-scores. However, in the multivariate analysis adjusted for variables of interest, no statistical significance was found for any of the models.

CONCLUSION

The presence, quantity, and location of WMH were not associated with the analyzed motor and non-motor manifestations of PD.

Cerebral Small Vessel Disease Is Associated with Motor, Cognitive, and Emotional Dysfunction in Multiple System Atrophy

BACKGROUND

Cerebral small vessel disease (CSVD) has not been systematically studied in patients with multiple system atrophy (MSA).

OBJECTIVE

We sought to explore whether MSA patients suffer from a heavier CSVD burden relative to healthy individuals and whether CSVD has a relationship with motor, cognitive, and emotional dysfunction in patients with MSA.

METHODS

This study consecutively recruited 190 MSA patients and 190 matched healthy controls whose overall CSVD burden and single CSVD imaging markers (including white matter hyperintensity (WMH), microbleeds, lacunes, and enlarged perivascular spaces (EPVS)) were measured. Of the MSA patients, 118 completed multi-dimensional outcome assessments. Spearman's correlations and multivariable linear regressions were performed.

RESULTS

We observed a greater burden of overall CSVD, WMH, and EPVS in MSA patients compared with controls, but not for microbleeds and lacunes. Motor dysfunction and cognitive impairment were significantly worse in subjects with severe CSVD than those with none-to-mild CSVD. In patients with MSA, the severity of CSVD burden was positively associated with motor impairments as measured by the Unified Multiple System Atrophy Rating Scale-II (β= 2.430, p = 0.039) and Scale for the Assessment and Rating of Ataxia (β= 1.882, p = 0.015). Of CSVD imaging markers, different associations with MSA outcomes were displayed. WMH was associated with motor, cognitive, and emotional deficits, while the EPVS in the centrum semiovale, basal ganglia, and hippocampus regions was correlated only with motor severity, anxiety, and cognition, respectively. Similar findings were noted in MSA-cerebellar and MSA-parkinsonian patients.

CONCLUSIONS

Concomitant CSVD may be correlated with worse multi-dimensional dysfunction in patients with MSA.

Blood-brain barrier endothelial cells in neurodegenerative diseases: Signals from the "barrier"

As blood-brain barrier (BBB) disruption emerges as a common problem in the early stages of neurodegenerative diseases, the crucial roles of barrier-type brain endothelial cells (BECs), the primary part of the BBB, have been reported in the pathophysiology of neurodegenerative diseases. The mechanisms of how early vascular dysfunction contributes to the progress of neurodegeneration are still unclear, and understanding BEC functions is a promising start. Our understanding of the BBB has gone through different stages, from a passive diffusion barrier to a mediator of central-peripheral interactions. BECs serve two seemingly paradoxical roles: as a barrier to protect the delicate brain from toxins and as an interface to constantly receive and release signals, thus maintaining and regulating the homeostasis of the brain. Most previous studies about neurodegenerative diseases focus on the loss of barrier functions, and far too little attention has been paid to the active regulations of BECs. In this review, we present the current evidence of BEC dysfunction in neurodegenerative diseases and explore how BEC signals participate in the pathogenesis of neurodegenerative diseases.

The effect of cardiovascular risk on disease progression in de novo Parkinson's disease patients: An observational analysis

Background

Currently available treatment options for Parkinson's disease are symptomatic and do not alter the course of the disease. Recent studies have raised the possibility that cardiovascular risk management may slow the progression of the disease.

Objectives

We estimated the effect of baseline cardiovascular risk factors on the progression of Parkinson's disease, using measures for PD-specific motor signs and cognitive functions.

Methods

We used data from 424 de novo Parkinson's disease patients and 199 age-matched controls from the observational, multicenter Parkinson's Progression Markers Initiative (PPMI) study, which included follow-up of up to 9 years. The primary outcome was the severity of PD-specific motor signs, assessed with the MDS-UPDRS part III in the "OFF"-state. The secondary outcome was cognitive function, measured with the Montreal Cognitive Assessment, Symbol Digit Modalities Test, and Letter-Number Sequencing task. Exposures of interest were diabetes mellitus, hypertension, body mass index, cardiovascular event history and hypercholesterolemia, and a modified Framingham risk score, measured at baseline. The effect of each of these exposures on disease progression was modeled using linear mixed models, including adjustment for identified confounders. A secondary analysis on the Tracking Parkinson's cohort including 1,841 patients was performed to validate our findings in an independent patient cohort.

Results

Mean age was 61.4 years, and the average follow-up was 5.5 years. We found no statistically significant effect of any individual cardiovascular risk factor on the MDS-UPDRS part III progression (all 95% confidence intervals (CIs) included zero), with one exception: in the PD group, the estimated effect of a one-point increase in body mass index was 0.059 points on the MDS-UPDRS part III per year (95% CI: 0.017 to 0.102). We found no evidence for an effect of any of the exposures on the rate of change in cognitive functioning in the PD group. Similar results were observed for the Tracking Parkinson's cohort (all 95% CIs overlapped with PPMI), but the 95% CI of the effect of body mass index on the MDS-UPDRS part III progression included zero.

Conclusions

Based on this analysis of two large cohorts of de novo PD patients, we found no evidence to support clinically relevant effects of cardiovascular risk factors on the clinical progression of Parkinson's disease.

Effects of Hypertension on Alzheimer's Disease and Related Disorders

PURPOSE OF REVIEW

To review the pathophysiology of hypertension in Alzheimer's disease and related dementias and explore the current landscape of clinical trials involving treatment of hypertension to improve cognition.

RECENT FINDINGS

Hypertension is increasingly recognized as a contributor to cognitive impairment. Clinical trials that explore blood pressure reductions with cognitive outcomes have been promising. Various antihypertensives have been evaluated in clinical trials, with growing interest in those agents that impact the renin-angiotensin-aldosterone system due to its own association with cognitive impairment. No antihypertensive agent has been found to be superior to others in reducing cognitive impairment risk or conferring neuroprotective benefits. In this review, the pathophysiology of and clinical trial data involving hypertension and dementia will be explored. Hypertension is a significant risk factor for the development of neurodegenerative dementias, and clinical trials have been overall favorable in improving cognition by reductions in blood pressure using antihypertensive agents.

Molecular and Cellular Interactions in Pathogenesis of Sporadic Parkinson Disease

An increasing number of the population all around the world suffer from age-associated neurodegenerative diseases including Parkinson’s disease (PD). This disorder presents different signs of genetic, epigenetic and environmental origin, and molecular, cellular and intracellular dysfunction. At the molecular level, α-synuclein (αSyn) was identified as the principal molecule constituting the Lewy bodies (LB). The gut microbiota participates in the pathogenesis of PD and may contribute to the loss of dopaminergic neurons through mitochondrial dysfunction. The most important pathogenetic link is an imbalance of Ca²⁺ ions, which is associated with redox imbalance in the cells and increased generation of reactive oxygen species (ROS). In this review, genetic, epigenetic and environmental factors that cause these disorders and their cause-and-effect relationships are considered. As a constituent of environmental factors, the example of organophosphates (OPs) is also reviewed. The role of endothelial damage in the pathogenesis of PD is discussed, and a ‘triple hit hypothesis’ is proposed as a modification of Braak’s dual hit one. In the absence of effective therapies for neurodegenerative diseases, more and more evidence is emerging about the positive impact of nutritional structure and healthy lifestyle on the state of blood vessels and the risk of developing these diseases.

Effect of cerebral small vessel disease on cognitive impairment in Parkinson's disease

OBJECTIVES

To explore the association between cerebral small vessel disease (cSVD) and cognitive impairment (CI) in Parkinson's disease (PD).

METHODS

81 PD patients were recruited into the study from September 2018 to December 2020. The demographic characteristics and radiologic and laboratory data were collected. Cognitive assessments were carried out using the Montreal Cognitive Assessment. The association between cSVD and cognitive impairment was analyzed using univariate and binary logistic regression analysis.

RESULTS

The binary logistic regression analysis showed that, after correcting for age, educational years, hyperhomocysteinemia, hypertension, and diabetes mellitus, total cSVD scores (OR 1.55, 95% CI 1.07-2.27, P = 0.02), the presence of paraventricular white matter hyperintensity (PVH) (OR 11.78, 95% CI 3.08-45.01, P < 0.001), white matter hyperintensity (WMH) (OR 7.95, 95% CI 2.28-27.79, P = 0.001), and perivascular space (PVS) (OR 6.66, 95% CI 2.08-21.40, P = 0.001) were independent risk factors for PD-CI.

CONCLUSION

The presence of cSVD was associated with cognitive dysfunction in patients with PD. It may be beneficial to manage cSVD to prevent the progression of cognitive impairment in patients with PD.

Enlarged perivascular spaces are linked to freezing of gait in Parkinson's disease

Objective

Freezing of gait (FOG) is one of common and disabling gait impairments of Parkinson's disease (PD). White matter hyperintensity (WMH) and lacunes, as common manifestations of cerebral small vessel diseases (CSVD), have been reported to be associated with gait function in PD patients. However, in the cases with FOG which present with extensive WMH or lacunes, it actually is difficult to distinguish pure PD pathology from vascular origin or combined effects. So far little is known about the correlation between enlarged perivascular space (PVS) and FOG in PD patients. This study aims to explore the role of enlarged PVS in FOG in PD patients.

Methods

A total of 95 patients with PD in the absence of obvious WMH and lacunes were included in our study, which were divided into PD-FOG (+) group and PD-FOG (-) group. Demographic and clinical data were investigated. Enlarged PVS in the centrum semiovale (CSO) and basal ganglia (BG) were assessed. The association between enlarged PVS and FOG in patients with PD was analyzed using the multivariate models and the Spearman's correlation.

Results

There were 36 PD patients grouped into PD-FOG (+) (37.9%), with an older age, a longer PD disease duration, and larger numbers of enlarged PVS in CSO and BG compared with PD-FOG (-) group. The highest-severity degree of enlarged PVS burden in CSO was independently associated with FOG in patients with PD [adjusted odds ratio (OR), 3.869; p = 0.022 in multivariable model]. The percentages of FOG case increased accompanied by the aggravation of enlarged PVS located in CSO. The grade and count of enlarged PVS in CSO and BG both correlated with FOGQ score in PD patients.

Conclusion

Enlarged PVS, particularly in CSO, are associated with FOG in patients with PD, which provides a novel perspective for the mechanisms of FOG in PD.

Characteristics of Cognitive Impairment and Their Relationship With Total Cerebral Small Vascular Disease Score in Parkinson's Disease

Background

This study aimed to investigate the characteristics of cognitive dysfunctions and their relationship with total cerebral small vascular disease (CSVD) in Parkinson’s disease (PD).

Methods

A total of 174 idiopathic PD patients who underwent brain magnetic resonance imaging (MRI) were recruited. Demographic information, vascular disease risk factors, motor function (MDS-UPDRS III score), and cognitive level (MoCA, MMSE) were collected for these patients. The total CSVD burden was scored based on lacunes, enlarged perivascular spaces (EPVS), high-grade white matter hyperintensities (WMH), and cerebral microbleeds (CMBs) for each subject.

Results

Cognitive scores on MoCA for language, delayed recall, and orientation were significantly reduced in PD patients with CSVD burden ≥ 1 than in those with CSVD burden = 0. Educational level, PDQ 39, and CSVD burden were significantly associated with MoCA scores in individuals with PD. For the whole group, the full model accounted for 33.6% variation in total MoCA scores. In which, CSVD burden explained 2.7% of the results, and the detection of lacunes, WMH, EPVS, and strictly lobar CMBs were significantly correlated with MoCA scores. The stability of the outcomes was confirmed by sensitivity analysis.

Conclusion

CSVD can independently contribute to cognitive decline in PD and cause damage in specific cognitive domains. Promoting neurovascular health may help preserve cognitive functions in PD.

The interplay between small vessel disease and Parkinson disease pathology: A longitudinal study

BACKGROUND

Cerebral small vessel disease (SVD) related brain changes have been found associated with various clinical symptoms of Parkinson disease (PD). On the other hand, PD pathology and treatment may also accelerate SVD progression.

OBJECTIVE

The aim of this study is to explore the interplay between SVD and PD pathology using longitudinal dataset.

METHODS

We screened 66 healthy controls (HCs) and 114 patients from the Parkinson Progression Markers Initiative (PPMI) database. The peak width of skeletonized mean diffusivity (PSMD) was quantified from diffusion tensor images to reflect vascular pathologies at baseline and 24 months follow-up, and dopamine transporter (DAT) imaging data was used to represent the extent of dopaminergic neuronal degeneration at the same point time. We compared the PSMD between PD patients and HCs, and analyzed whether PSMD and DAT availability could predict each other's progression using multiple regression analyses in PD patients.

RESULTS

PSMD at baseline had no significant difference between the HCs and patients with PD (P = 0.169). Higher baseline PSMD was associated with less DAT reduction in the caudate (β = 0.216, P = 0.029), but not the putamen (β = 0.058, P = 0.552) in PD patients. Baseline caudate and putamen DAT availability had no significant association with PSMD progression (β = -0.006, P = 0.950; β = 0.017, P = 0.860, respectively).

CONCLUSIONS

Mild SVD might slow down PD pathology progression, while the effect of PD pathology on the progression of SVD was not significant.

Association of Cerebral Small Vessel Disease With Gait and Balance Disorders

Cerebral small vessel disease (CSVD) is a common cerebrovascular disease and an important cause of gait and balance disorders. Gait and balance disorders can further lead to an increased risk of falls and a decreased quality of life. CSVD can damage gait and balance function by affecting cognitive function or directly disrupting motor pathways, and different CSVD imaging features have different characteristics of gait and balance impairment. In this article, the correlation between different imaging features of sporadic CSVD and gait and balance disorders has been reviewed as follows, which can provide beneficial help for standardized management of CSVD.

Study of BBB Dysregulation in Neuropathogenicity Using Integrative Human Model of Blood-Brain Barrier

The blood-brain barrier (BBB) is a cellular and physical barrier with a crucial role in homeostasis of the brain extracellular environment. It controls the imports of nutrients to the brain and exports toxins and pathogens. Dysregulation of the blood-brain barrier increases permeability and contributes to pathologies, including Alzheimer's disease, epilepsy, and ischemia. It remains unclear how a dysregulated BBB contributes to these different syndromes. Initial studies on the role of the BBB in neurological disorders and also techniques to permit the entry of therapeutic molecules were made in animals. This review examines progress in the use of human models of the BBB, more relevant to human neurological disorders. In recent years, the functionality and complexity of in vitro BBB models have increased. Initial efforts consisted of static transwell cultures of brain endothelial cells. Human cell models based on microfluidics or organoids derived from human-derived induced pluripotent stem cells have become more realistic and perform better. We consider the architecture of different model generations as well as the cell types used in their fabrication. Finally, we discuss optimal models to study neurodegenerative diseases, brain glioma, epilepsies, transmigration of peripheral immune cells, and brain entry of neurotrophic viruses and metastatic cancer cells.

Deep Learning Paradigm for Cardiovascular Disease/Stroke Risk Stratification in Parkinson’s Disease Affected by COVID-19: A Narrative Review

Background and Motivation: Parkinson’s disease (PD) is one of the most serious, non-curable, and expensive to treat. Recently, machine learning (ML) has shown to be able to predict cardiovascular/stroke risk in PD patients. The presence of COVID-19 causes the ML systems to become severely non-linear and poses challenges in cardiovascular/stroke risk stratification. Further, due to comorbidity, sample size constraints, and poor scientific and clinical validation techniques, there have been no well-explained ML paradigms. Deep neural networks are powerful learning machines that generalize non-linear conditions. This study presents a novel investigation of deep learning (DL) solutions for CVD/stroke risk prediction in PD patients affected by the COVID-19 framework. Method: The PRISMA search strategy was used for the selection of 292 studies closely associated with the effect of PD on CVD risk in the COVID-19 framework. We study the hypothesis that PD in the presence of COVID-19 can cause more harm to the heart and brain than in non-COVID-19 conditions. COVID-19 lung damage severity can be used as a covariate during DL training model designs. We, therefore, propose a DL model for the estimation of, (i) COVID-19 lesions in computed tomography (CT) scans and (ii) combining the covariates of PD, COVID-19 lesions, office and laboratory arterial atherosclerotic image-based biomarkers, and medicine usage for the PD patients for the design of DL point-based models for CVD/stroke risk stratification. Results: We validated the feasibility of CVD/stroke risk stratification in PD patients in the presence of a COVID-19 environment and this was also verified. DL architectures like long short-term memory (LSTM), and recurrent neural network (RNN) were studied for CVD/stroke risk stratification showing powerful designs. Lastly, we examined the artificial intelligence bias and provided recommendations for early detection of CVD/stroke in PD patients in the presence of COVID-19. Conclusion: The DL is a very powerful tool for predicting CVD/stroke risk in PD patients affected by COVID-19.

Morphological basis of Parkinson disease-associated cognitive impairment: an update

Cognitive impairment is one of the most salient non-motor symptoms of Parkinson disease (PD) that poses a significant burden on the patients and carers as well as being a risk factor for early mortality. People with PD show a wide spectrum of cognitive dysfunctions ranging from subjective cognitive decline and mild cognitive impairment (MCI) to frank dementia. The mean frequency of PD with MCI (PD-MCI) is 25.8% and the pooled dementia frequency is 26.3% increasing up to 83% 20 years after diagnosis. A better understanding of the underlying pathological processes will aid in directing disease-specific treatment. Modern neuroimaging studies revealed considerable changes in gray and white matter in PD patients with cognitive impairment, cortical atrophy, hypometabolism, dopamine/cholinergic or other neurotransmitter dysfunction and increased amyloid burden, but multiple mechanism are likely involved. Combined analysis of imaging and fluid markers is the most promising method for identifying PD-MCI and Parkinson disease dementia (PDD). Morphological substrates are a combination of Lewy- and Alzheimer-associated and other concomitant pathologies with aggregation of α-synuclein, amyloid, tau and other pathological proteins in cortical and subcortical regions causing destruction of essential neuronal networks. Significant pathological heterogeneity within PD-MCI reflects deficits in various cognitive domains. This review highlights the essential neuroimaging data and neuropathological changes in PD with cognitive impairment, the amount and topographical distribution of pathological protein aggregates and their pathophysiological relevance. Large-scale clinicopathological correlative studies are warranted to further elucidate the exact neuropathological correlates of cognitive impairment in PD and related synucleinopathies as a basis for early diagnosis and future disease-modifying therapies.

Cardiovascular/Stroke Risk Stratification in Parkinson's Disease Patients Using Atherosclerosis Pathway and Artificial Intelligence Paradigm: A Systematic Review

Parkinson’s disease (PD) is a severe, incurable, and costly condition leading to heart failure. The link between PD and cardiovascular disease (CVD) is not available, leading to controversies and poor prognosis. Artificial Intelligence (AI) has already shown promise for CVD/stroke risk stratification. However, due to a lack of sample size, comorbidity, insufficient validation, clinical examination, and a lack of big data configuration, there have been no well-explained bias-free AI investigations to establish the CVD/Stroke risk stratification in the PD framework. The study has two objectives: (i) to establish a solid link between PD and CVD/stroke; and (ii) to use the AI paradigm to examine a well-defined CVD/stroke risk stratification in the PD framework. The PRISMA search strategy selected 223 studies for CVD/stroke risk, of which 54 and 44 studies were related to the link between PD-CVD, and PD-stroke, respectively, 59 studies for joint PD-CVD-Stroke framework, and 66 studies were only for the early PD diagnosis without CVD/stroke link. Sequential biological links were used for establishing the hypothesis. For AI design, PD risk factors as covariates along with CVD/stroke as the gold standard were used for predicting the CVD/stroke risk. The most fundamental cause of CVD/stroke damage due to PD is cardiac autonomic dysfunction due to neurodegeneration that leads to heart failure and its edema, and this validated our hypothesis. Finally, we present the novel AI solutions for CVD/stroke risk prediction in the PD framework. The study also recommends strategies for removing the bias in AI for CVD/stroke risk prediction using the PD framework.

Addressing Blood–Brain Barrier Impairment in Alzheimer’s Disease

The blood–brain barrier (BBB) plays a vital role in maintaining the specialized microenvironment of the brain tissue. It facilitates communication while separating the peripheral circulation system from the brain parenchyma. However, normal aging and neurodegenerative diseases can alter and damage the physiological properties of the BBB. In this review, we first briefly present the essential pathways maintaining and regulating BBB integrity, and further review the mechanisms of BBB breakdown associated with normal aging and peripheral inflammation-causing neurodegeneration and cognitive impairments. We also discuss how BBB disruption can cause or contribute to Alzheimer’s disease (AD), the most common form of dementia and a devastating neurological disorder. Next, we document overlaps between AD and vascular dementia (VaD) and briefly sum up the techniques for identifying biomarkers linked to BBB deterioration. Finally, we conclude that BBB breakdown could be used as a biomarker to help diagnose cognitive impairment associated with normal aging and neurodegenerative diseases such as AD.

Lung function impairment in relation to cognition and vascular brain lesions: the Rotterdam Study

OBJECTIVE

To investigate the association of chronic obstructive pulmonary disease (COPD) and Preserved Ratio Impaired Spirometry (PRISm) with cognitive performance and presence of vascular brain lesions (VBL).

METHODS

We determined both cross-sectional and longitudinal association of lung function impairment with cognition, as well as cross-sectional association of lung function impairment with VBL, in the general population. Between 2009 and 2014 we included 3,941 participants from the Rotterdam Study with spirometry tests, brain MRI scans and cognition tests, of whom 1815 had follow-up data on cognition.

RESULTS

Our finding indicated that cross-sectionally, participants with PRISm or COPD GOLD2-4 had a worse global cognitive performance. We did not find differences in cognition over time between those with normal spirometry versus those with lung function impairment. In addition, PRISm and COPD GOLD2-4 were associated with a higher prevalence of lacunar infarcts compared to normal spirometry.

CONCLUSIONS

This study suggests that persons with COPD GOLD2-4 or restrictive lung function, defined as PRISm, are characterized by poorer global cognitive function and a higher prevalence of lacunar infarcts.

Neuropathological substrates of cognition in Parkinson's disease

Autopsy validation is still required for a definitive diagnosis of Parkinson's disease (Postuma et al., 2015), where the presence of Lewy bodies and Lewy neurites, composed primarily of alpha-synuclein, are observed in stereotyped patterns throughout regions of the brainstem, limbic, and neocortical regions of the brain (Braak et al., 2003). In spite of these relatively reliable observed patterns of alpha-synuclein pathology, there is a large degree of heterogeneity in the timing and features of neuropsychiatric and cognitive dysfunction in Parkinson's disease (Fereshtehnejad et al., 2015; Selikhova et al., 2009; Williams-Gray et al., 2013). Detailed studies of their neuropathological substrates of cognitive dysfunction and their associations with a variety of in vivo biomarkers have begun to disentangle this complex relationship, but ongoing multicentered, longitudinal studies of well-characterized and autopsy validated cases are still required.

Neuroimaging approaches to cognition in Parkinson's disease

While direct visualization of Lewy body accumulation within the brain is not yet possible in living Parkinson's disease patients, brain imaging studies offer insights into how the buildup of Lewy body pathology impacts different regions of the brain. Unlike biological biomarkers and purely behavioral research, these brain imaging studies therefore offer a unique opportunity to relate brain localization to cognitive function and dysfunction in living patients. Magnetic resonance imaging studies can reveal physical changes in brain structure as they relate to different cognitive domains and task specific impairments. Functional imaging studies use a combination of task and resting state magnetic resonance imaging, as well as positron emission tomography and single photon emission computed tomography, and can be used to determine changes in blood flow, neuronal activation and neurochemical changes in the brain associated with PD cognition and cognitive impairments. Other unique advantages to brain imaging studies are the ability to monitor changes in brain structure and function longitudinally as patients progress and the ability to study changes in brain function when patients are exposed to different pharmacological manipulations. This is particularly true when assessing the effects of dopaminergic replacement therapy on cognitive function in Parkinson's disease patients. Together, this chapter will describe imaging studies that have helped identify structural and functional brain changes associated with cognition, cognitive impairment, and dementia in Parkinson's disease.

Effect of cerebral small vessel disease on cognitive impairment in Parkinson's disease: a systematic review and meta-analysis

Background

The occurrence of various cerebrovascular diseases can easily induce cognitive impairment in the elderly. Therefore, it is of great clinical significance to correctly understand the relationship between these key pathogenic factors and cognitive impairment of Parkinson's disease. To explore the effect of cerebrovascular disease on cognitive impairment in Parkinson's disease by meta-analysis.

Methods

PubMed, Medline, Embase, and Web of Science databases were selected as the sources for the literature search. English language articles were included. Literature related to this study were published from January 2001 to January 2021. Literature was screened and the quality was evaluated. RevMan 5.3 software was used to perform the meta-analysis on the effects of cerebrovascular disease on cognitive impairment in Parkinson's disease.

Results

Six articles were finally included, involving a total of 5,552 cases. Of these, 2,684 were positive cases, accounting for 48.3%. Compared with patients with non-Parkinson's cognitive impairment, patients with cognitive impairment in Parkinson's disease caused by cerebral small vessel disease had significant differences in executive ability (OR =1.62, 95% CI: 1.21-2.16, P=0.001), memory (OR =1.48, 95% CI: 1.30-1.68, P<0.00001), information processing (OR =0.60, 95% CI: 0.35-1.03, P=0.07), language communication (OR= 4.72, 95% CI: 3.26-6.85, P<0.00001), and overall cognitive function (OR =0.72, 95% CI: 0.52-0.99, P=0.05).

Conclusions

A total of 6 studies were included in this meta-analysis on the influence of cerebral small vessel disease on cognitive impairment in Parkinson's disease. This study shows that cerebrovascular disease has different effects on all aspects of cognitive function of Parkinson's disease.

Baseline predictors of progression of Parkinson's disease in a sample of Egyptian patients: clinical and biochemical

Background

Clinical progression of Parkinson’s disease (PD) is highly heterogeneous, and its predictors are generally lacking. Identifying predictors of early disease progression is important for patients’ management and follow-up. The current study aims to identify clinical, neuroimaging and biochemical baseline predictors of motor progression in patients with PD. Forty-five PD patients were assessed at baseline, 6 months and 1 year using MDS-UPDRS total and subscores, Hoehn and Yahr (H&Y), Schwab and England (S&E), International Physical Activity Questionnaire (IPAQ). Baseline New Freezing of Gait Questionnaire (NFOG-Q), Berg Balance Scale (BBS), Ten-Meter Walking Test (10-MWT), and Time Up and Go Test (TUG), Non-Motor Symptoms Scale (NMSS), Beck Depression Inventory (BDI), PD questionnaire 39 (PDQ-39), MRI brain, uric acid, lipid profile and glycated hemoglobin were performed.

Results

Significant worsening of MDS-UPDRS total, part III scores, H&Y, S&E and IPAQ (p < 0.001) was detected. One-year progression of H&Y and S&E were significantly correlated to disease duration (p = 0.014, p = 0.025, respectively). Progression of H&Y was correlated to baseline TUG (p = 0.035). S&E progression was correlated to baseline MDS-UPDRS total score (rho = 0.478, p = 0.001) and part III (rho = 0.350, p = 0.020), H&Y (rho = 0.401, p = 0.007), PIGD (rho = 0.591, p < 0.001), NFOG-Q (rho = 0.498, p = 0.001), and TUG (rho = 0.565, p = 0.001). Using linear regression, there was no predictors of clinical progression among the used baseline variables.

Conclusion

Despite the significant motor and physical activity progression over 1 year that was correlated to baseline motor and gait severity, but without predictive value, further similar and longitudinal studies are warranted to detect predictors of early progression and confirm findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41983-022-00445-1.

Cognitive Performance is Associated with Altered Cerebral Hemodynamics Assessed by Transcranial Ultrasound in Parkinson's Disease

PURPOSE

Cognitive impairment (CI) is a common but debilitating non-motor symptom in Parkinson's disease (PD). Although cerebrovascular functions are related to cognitive performance in healthy individuals, such a relation in PD remains elusive. This study aims to assess the association between cerebrovascular function and cognitive performance in PD individuals.

PATIENTS AND METHODS

Two-hundred-and-one PD individuals were retrospectively included. They were subsequently divided into two groups: PD with normal cognition (PD-NC) and PD with CI (PD-CI). Cerebral hemodynamic characteristics of the middle cerebral arteries were assessed by transcranial ultrasound. The association between scores in each cognitive domain and cerebral hemodynamic parameters was further analyzed using regression analyses. Additionally, a binary logistic regression model with backward stepwise procedure was applied to build the model for discriminating CI in PD individuals. An independent dataset of additional 46 PD individuals was used further.

RESULTS

The PD-CI group showed a relatively lower end-diastolic blood flow velocity (EDV, p < 0.05) and a higher resistive index (RI, p < 0.05) compared to the PD-NC group. RI showed significant associations with the memory item score of Montreal Cognitive Assessment (p < 0.05). A model combining clinical and hemodynamic variables was established with optimal efficiency (area under the curve, AUC = 0.651). Further replication of the model in an independent dataset yielded a great consistency (AUC = 0.704).

CONCLUSION

In our study, cerebrovascular functions were significantly associated with the cognitive performance in PD individuals, especially with the memory task. The established model was effective in identifying CI in PD individuals, which might be a potentially useful tool to screen the cognitive decline in PD individuals at an early stage of the disease. Further studies with larger sample sizes in different populations are warranted.

Vascular Risk Factors and Cognition in Multiple System Atrophy

Objective: Vascular risk factors have been reported to be associated with cognitive impairment (CI) in the general population, but their role on CI in multiple system atrophy (MSA) is unclear. This study aimed to explore the relationship between vascular risk factors and CI in patients with MSA. Methods: The clinical data and vascular risk factors were collected. The Montreal Cognitive Assessment tool was used to test the cognitive function of patients with MSA. Binary logistic regression was used to analyze the correlation between vascular risk factors and CI. Results: A total of 658 patients with MSA with a mean disease duration of 2.55 ± 1.47 years were enrolled. In MSA patients, hypertension was recorded in 20.2%, diabetes mellitus in 10.3%, hyperlipidemia in 10.2%, smoking in 41.2%, drinking in 34.8%, and obesity in 9.6%. The prevalence of CI in patients with MSA, MSA with predominant parkinsonism (MSA-P), and MSA with predominant cerebellar ataxia (MSA-C) was 45.0, 45.1, and 44.9%, respectively. In the binary logistic regression model, patients with more than one vascular risk factors were significantly more likely to have CI in MSA (OR = 4.298, 95% CI 1.456-12.691, P = 0.008) and MSA-P (OR = 6.952, 95% CI 1.390-34.774, P = 0.018), after adjusting for age, sex, educational years, disease duration, and total Unified multiple system atrophy rating scale scores. Conclusion: Multiple vascular risk factors had a cumulative impact on CI in MSA. Therefore, the comprehensive management of vascular risk factors in MSA should not be neglected.

Ultrasonographic Changes in Brain Hemodynamics in Patients with Parkinson's Disease and Risk Factors for Cerebrovascular Disease: A Pilot Study

Recent epidemiological studies have revealed a correlation between atypical features and worse functional outcomes in Parkinson's disease (PD) patients with cerebrovascular disease (CVD). We aimed to evaluate the brain hemodynamics of PD patients with risk factors for CVD using Doppler ultrasonography. In this prospective pilot study, we randomly included 27 outpatients diagnosed with PD. Transcranial color-coded sonography (TCCS) examinations were performed, obtaining measurements of middle cerebral artery mean flow velocities (Vm), the resistance index (RI), and the pulsatility index (PI). The breath-holding index (BHI) was used to assess cerebrovascular reactivity (cVR). Standardized functional scales (UPDRS III, Hoehn & Yahr scale, and MoCA) were administered. The patients were divided into two groups: those with two or more vascular risk factors (PDvasc) and those with fewer than two vascular risk factors (PDnvasc). Patients in the PDvasc group showed higher PI (1.00 vs. 0.85; p=0.020), RI (0.59 vs. 0.5; p=0.05), H&Y mean (2.4 vs. 1.4; p=0.036), higher frequency of altered cVR (90.9% vs. 25.0%; p=0.001), and lower BHI (0.46 vs. 1.01; p=0.027). We also divided the patients in other two groups: one with patients with classical and another with akinetic-rigid PD clinical type. Patients with the akinetic-rigid type of PD had significantly higher RI (0.60 vs. 0.51; p=0.03), PI (0.99 vs. 0.77; p=0.03), higher frequency of altered cVR (80% vs. 35%; p=0.02), and lower BHI (0.48 vs. 0.96; p=0.05) than patients with classic-type PD. We concluded that TCCS displays impaired cerebrovascular reactivity and a more severe disease pattern in Parkinsonian patients with two or more risk factors for CVD and in the akinetic-rigid type. Doppler ultrasonography may be a useful tool in a clinical setting to investigate PD patients.

Parkinsonism and cerebrovascular disease

The relationship between cerebrovascular disease and parkinsonism is commonly seen in everyday clinical practice but remains ill-defined and under-recognised with little guidance for the practising neurologist. We attempt to define this association and to illustrate key clinical, radiological and pathological features of the syndrome of Vascular Parkinsonism (VaP). VaP is a major cause of morbidity in the elderly associated with falls, hip fractures and cognitive impairment. Although acute parkinsonism is reported in the context of an acute cerebrovascular event, the vast majority of VaP presents as an insidious syndrome usually in the context of vascular risk factors and radiological evidence of small vessel disease. There may be an anatomic impact on basal ganglia neuronal networks, however the effect of small vessel disease (SVD) on these pathways is not clear. There are now established reporting standards for radiological features of SVD on MRI. White matter hyperintensities and lacunes have been thought to be the representative radiological features of SVD but other features such as the perivascular space are gaining more importance, especially in context of the glymphatic system. It is important to consider VaP in the differential diagnosis of Parkinson disease (PD) and in these situations, neuroimaging may offer diagnostic benefit especially in those patients with atypical presentations or refractoriness to levodopa. Proactive management of vascular risk factors, monitoring of bone density and an exercise program may offer easily attainable therapeutic targets in PD and VaP. Levodopa therapy should be considered in patients with VaP, however the dose and effect may be different from use in PD. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Parkinsonism and dementia

The aim of the present review is to summarize literature data on dementia in parkinsonian disorders. Cognitive decline and the gradual development of dementia are considered to be key features in the majority of parkinsonian conditions. The burden of dementia in everyday life of parkinsonian patients and their caregivers is vast and can be even more challenging to handle than the motor component of the disease. Common pathogenetic mechanisms involve the aggregation and spreading of abnormal proteins like alpha-synuclein, tau or amyloid in cortical and subcortical regions with subsequent dysregulation of multiple neurotransmitter systems. The degree of cognitive deterioration in these disorders is variable and ranges from mild cognitive impairment to severe cognitive dysfunction. There is also variation in the number and type of affected cognitive domains which can involve either a single domain like executive or visuospatial function or multiple ones. Novel genetic, biological fluid or imaging biomarkers appear promising in facilitating the diagnosis and staging of dementia in parkinsonian conditions. A significant part of current research in Parkinson's disease and other parkinsonian syndromes is targeted towards the cognitive aspects of these disorders. Stabilization or amelioration of cognitive outcomes represents a primary endpoint in many ongoing clinical trials for novel disease modifying treatments in this field. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Diabetes Mellitus and Parkinson's Disease: A Systematic Review and Meta-Analyses

BACKGROUND

A link between diabetes mellitus (DM) and Parkinson's disease (PD) have been proposed but evidence are sparse and inconsistent.

OBJECTIVE

Perform a systematic review of all evidence that link DM and PD characterising the prevalence of DM in PD patients, the risk of developing PD in DM patients and the influence of DM on PD severity and progression.

METHODS

MEDLINE, Scopus, and Cochrane Library from inception to June 30, 2021 were searched. Studies reporting prevalence, incidence, severity and disease progression of DM and PD were included. Prevalence of DM in PD and incidence of PD in DM patients, and characteristics of PD.

RESULTS

A total of 21 studies (n = 11,396) included data on DM prevalence in PD patients, 12 studies (n = 17,797,221) included data on incidence of PD in DM patients, and 10 studies (n = 2,482) included data on DM impact on PD severity and disease progression. The prevalence of DM in PD patients was 10.02 %, (95%C.I. 7.88 -12.16), DM patients showed a higher risk of developing PD (OR: 1.34 95%CI 1.26-1.43 p < 0.0001) compared to non-DM, and PD patients with DM showed a greater severity of motor symptoms, with higher Hoehn and Yahr stage (SMD: 0.36 95%CI 0.12-0.60; p < 0.001) and higher UPDRS (SMD 0.60 95%CI 0.28-0.92; p < 0.001) compared with PD patients without DM.

CONCLUSION

Although the prevalence of DM in PD patients is similar to the general population, patients with DM have a higher risk of developing PD, and the presence of DM is associated with greater PD severity and faster progression, which suggests that DM may be a facilitating factor of neurodegeneration.

Adverse effects of hypertension, supine hypertension, and perivascular space on cognition and motor function in PD

Dilated perivascular space (dPVS) has recently been reported as a biomarker for cognitive impairment in Parkinson’s disease (PD). However, comprehensive interrelationships between various clinical risk factors, dPVS, white-matter hyperintensities (WMH), cognition, and motor function in PD have not been studied yet. The purpose of this study was to test whether dPVS might mediate the effect of clinical risk factors on WMH, cognition, and motor symptoms in PD patients. A total of 154 PD patients were assessed for vascular risk factors (hypertension, diabetes mellitus, and dyslipidemia), autonomic dysfunction (orthostatic hypotension and supine hypertension [SH]), APOE ε4 genotype, rapid eye movement sleep-behavior disorder, motor symptoms, and cognition status. The degree of dPVS was evaluated in the basal ganglia (BG) and white matter using a 5-point visual scale. Periventricular, deep, and total WMH severity was also assessed. Path analysis was performed to evaluate the associations of these clinical factors and imaging markers with cognitive status and motor symptoms. Hypertension and SH were significantly associated with more severe BGdPVS, which was further associated with higher total WMH, consequently leading to lower cognitive status. More severe BGdPVS was also associated with worse motor symptoms, but without mediation of total WMH. Similar associations were seen when using periventricular WMH as a variable, but not when using deep WMH as a variable. In conclusion, BGdPVS mediates the effect of hypertension and SH on cognitive impairment via total and periventricular WMH, while being directly associated with more severe motor symptoms.

Normal-sized basal ganglia perivascular space related to motor phenotype in Parkinson freezers

Changes in basal ganglia (BG) perivascular spaces (PVSs) are related to motor and cognitive behaviors in Parkinson’s disease (PD). However, the correlation between the initial motor phenotype and PVSs distribution/burden in PD freezing of gait (FOG) remains unclear. In addition, the normal-sized PVSs (nPVSs) have not been well-studied. With high-resolution 7T-MRI, we studied nPVSs burden in BG, thalamus, midbrain and centrum semiovale. The numbers and volume of nPVSs were assessed in 10 healthy controls, 10 PD patients without FOG, 20 with FOG [10 tremor dominant (TD), 10 non-TD subtype]. Correlation analyses were further performed in relation to clinical parameters. In this proof of concept study, we found that the nPVS burden of bilateral and right BG were significantly higher in freezers. A negative correlation existed between the tremor score and BG-nPVSs count. A positive correlation existed between the levodopa equivalent daily dose and BG-nPVSs count. The nPVS burden correlated with the progression to FOG in PD, but the distribution and burden of nPVS differ in TD vs. non-TD subtypes. High resolution 7T-MRI is a sensitive and reliable tool to evaluate BG-nPVS, and may be a useful imaging marker for predicting gait impairment that may evolve into FOG in PD.

Non-Invasive Evaluation of Cerebral Microvasculature Using Pre-Clinical MRI: Principles, Advantages and Limitations

Alterations to the cerebral microcirculation have been recognized to play a crucial role in the development of neurodegenerative disorders. However, the exact role of the microvascular alterations in the pathophysiological mechanisms often remains poorly understood. The early detection of changes in microcirculation and cerebral blood flow (CBF) can be used to get a better understanding of underlying disease mechanisms. This could be an important step towards the development of new treatment approaches. Animal models allow for the study of the disease mechanism at several stages of development, before the onset of clinical symptoms, and the verification with invasive imaging techniques. Specifically, pre-clinical magnetic resonance imaging (MRI) is an important tool for the development and validation of MRI sequences under clinically relevant conditions. This article reviews MRI strategies providing indirect non-invasive measurements of microvascular changes in the rodent brain that can be used for early detection and characterization of neurodegenerative disorders. The perfusion MRI techniques: Dynamic Contrast Enhanced (DCE), Dynamic Susceptibility Contrast Enhanced (DSC) and Arterial Spin Labeling (ASL), will be discussed, followed by less established imaging strategies used to analyze the cerebral microcirculation: Intravoxel Incoherent Motion (IVIM), Vascular Space Occupancy (VASO), Steady-State Susceptibility Contrast (SSC), Vessel size imaging, SAGE-based DSC, Phase Contrast Flow (PC) Quantitative Susceptibility Mapping (QSM) and quantitative Blood-Oxygenation-Level-Dependent (qBOLD). We will emphasize the advantages and limitations of each strategy, in particular on applications for high-field MRI in the rodent's brain.