Autonomic dysfunction in Parkinson's disease: Implications for pathophysiology, diagnosis, and treatment

Impact of autonomic symptoms on the clinical course of Parkinson's disease

PURPOSE

Patients with Parkinson's disease (PD) exhibit various degrees of autonomic symptoms, which may be associated with Lewy body pathology distributed extensively in the autonomic nervous system. We hypothesized that the severity of autonomic symptoms reflects the severity of PD-related pathology, resulting in poor outcomes. The purpose of this study was to evaluate the impact of autonomic symptoms on PD progression.

METHODS

We conducted a follow-up study among consecutive patients with PD at Dokkyo Medical University Hospital. Patients underwent comprehensive baseline evaluations and were classified into high and low autonomic symptom groups using the Scale for Outcomes in Parkinson's Disease-Autonomic (SCOPA-AUT). The Kaplan‒Meier survival curves were used to analyze the time to discontinuation of their visits because of PD-related endpoints and to evaluate the association with high SCOPA-AUT scores.

RESULTS

Of the 101 patients, 74 (73%) met the inclusion criteria. During the follow-up period (mean 1654 days), 22/74 patients reached PD-related endpoints (death, 4; hospitalization, 9; nursing home institutionalization, 9). PD patients with high SCOPA-AUT scores reached the endpoints faster than those with low SCOPA-AUT scores. A high SCOPA-AUT score, including gastrointestinal, urinary, and thermoregulation domains; high motor symptom scores; and low specific binding ratios (SBRs) on 123I FP-CIT-SPECT (DAT-SPECT) were associated with reaching PD-related endpoints. A high SCOPA-AUT score was associated with reaching the endpoints even after adjustment for covariates.

CONCLUSIONS

Patients with high autonomic symptom scores had a greater risk of reaching PD-related endpoints than patients with low autonomic symptom scores.

Cardiovascular history and risk of idiopathic Parkinson's disease: a cross-sectional observational study

BACKGROUND

Parkinson's disease (PD), while often associated with its distinctive motor symptoms, can also exert a notable impact on the cardiovascular system due to the development of severe autonomic dysfunction. One of the initial indicators of PD is the appearance of cardiovascular dysautonomia. As such, it is vital to monitor and manage cardiovascular health of individuals with PD, as it may have clinical implications in the development of commonly recognized motor and non-motor aspects of the disease. To study the association of history of cardiovascular disease (CVD) with occurrence and severity of PD, here, we lend data on the association of CVD history with the frequency and the occurrence of idiopathic PD (iPD) using data from the Luxembourg Parkinson's study (iPD n = 676 patients and non-PD n = 874 controls).

RESULTS

We report that patients with a history of CVD are at high risk of developing iPD (odds ratio; OR = 1.56, 95% confidence interval; CI 1.09-2.08). This risk is stronger in males and remains significant after adjustment with confounders (OR 1.55, 95% CI 1.05-2.30). This increased susceptibility to iPD is linked to the severity of iPD symptoms mainly the non-motor symptoms of daily living (MDS-UPDRS I) and motor complications (MDS-UPDRS IV) in the affected individuals.

CONCLUSION

Individuals with history of CVD have a high risk of developing severe forms of iPD. This observation suggests that careful monitoring and management of patients with a history of cardiac problems may reduce the burden of iPD.

Levodopa-induced dyskinesia in Parkinson's disease: Insights from cross-cohort prognostic analysis using machine learning

BACKGROUND

Prolonged levodopa treatment in Parkinson's disease (PD) often leads to motor complications, including levodopa-induced dyskinesia (LID). Despite continuous levodopa treatment, some patients do not develop LID symptoms, even in later stages of the disease.

OBJECTIVE

This study explores machine learning (ML) methods using baseline clinical characteristics to predict the development of LID in PD patients over four years, across multiple cohorts.

METHODS

Using interpretable ML approaches, we analyzed clinical data from three independent longitudinal PD cohorts (LuxPARK, n = 356; PPMI, n = 484; ICEBERG, n = 113) to develop cross-cohort prognostic models and identify potential predictors for the development of LID. We examined cohort-specific and shared predictive factors, assessing model performance and stability through cross-validation analyses.

RESULTS

Consistent cross-validation results for single and multiple cohort analyses highlighted the effectiveness of the ML models and identified baseline clinical characteristics with significant predictive value for the LID prognosis in PD. Predictors positively correlated with LID include axial symptoms, freezing of gait, and rigidity in the lower extremities. Conversely, the risk of developing LID was inversely associated with the occurrence of resting tremors, higher body weight, later onset of PD, and visuospatial abilities.

CONCLUSIONS

This study presents interpretable ML models for dyskinesia prognosis with significant predictive power in cross-cohort analyses. The models may pave the way for proactive interventions against dyskinesia in PD by optimizing levodopa dosing regimens and adjunct treatments with dopamine agonists or MAO-B inhibitors, and by employing non-pharmacological interventions such as dietary adjustments affecting levodopa absorption for high-risk LID patients.

Insular and limbic abnormal functional connectivity in early-stage Parkinson's disease patients with autonomic dysfunction

Autonomic symptoms in Parkinson's disease result from variable involvement of the central and peripheral systems, but many aspects remain unclear. The analysis of functional connectivity has shown promising results in assessing the pathophysiology of Parkinson's disease. This study aims to investigate the association between autonomic symptoms and cortical functional connectivity in early Parkinson's disease patients using high-density EEG. 53 early Parkinson's disease patients (F/M 18/35) and 49 controls (F/M 20/29) were included. Autonomic symptoms were evaluated using the Scales for Outcomes in Parkinson's disease-Autonomic Dysfunction score. Data were recorded with a 64-channel EEG system. We analyzed cortical functional connectivity, based on weighted phase-lag index, in θ-α-β-low-γ bands. A network-based statistic was used to perform linear regression between Scales for Outcomes in Parkinson's disease-Autonomic Dysfunction score and functional connectivity in Parkinson's disease patients. We observed a positive relation between the Scales for Outcomes in Parkinson's disease-Autonomic Dysfunction score and α-functional connectivity (network τ = 2.8, P = 0.038). Regions with higher degrees were insula and limbic lobe. Moreover, we found positive correlations between the mean connectivity of this network and the gastrointestinal, cardiovascular, and thermoregulatory domains of Scales for Outcomes in Parkinson's disease-Autonomic Dysfunction. Our results revealed abnormal functional connectivity in specific areas in Parkinson's disease patients with greater autonomic symptoms. Insula and limbic areas play a significant role in the regulation of the autonomic system. Increased functional connectivity in these regions might represent the central compensatory mechanism of peripheral autonomic dysfunction in Parkinson's disease.

The misfolding mystery: α-synuclein and the pathogenesis of Parkinson's disease

Neurodegenerative diseases such as Parkinson's disease (PD) are characterized by the death of neurons in specific areas of the brain. One of the proteins that is involved in the pathogenesis of PD is α-synuclein (α-syn). α-Syn is a normal protein that is found in all neurons, but in PD, it misfolds and aggregates into toxic fibrils. These fibrils can then coalesce into pathological inclusions, such as Lewy bodies and Lewy neurites. The pathogenic pathway of PD is thought to involve a number of steps, including misfolding and aggregation of α-syn, mitochondrial dysfunction, protein clearance impairment, neuroinflammation and oxidative stress. A deeper insight into the structure of α-syn and its fibrils could aid in understanding the disease's etiology. The prion-like nature of α-syn is also an important area of research. Prions are misfolded proteins that can spread from cell to cell, causing other proteins to misfold as well. It is possible that α-syn may behave in a similar way, spreading from cell to cell and causing a cascade of misfolding and aggregation. Various post-translational alterations have also been observed to play a role in the pathogenesis of PD. These alterations can involve a variety of nuclear and extranuclear activities, and they can lead to the misfolding and aggregation of α-syn. A better understanding of the pathogenic pathway of PD could lead to the development of new therapies for the treatment of this disease.

Short term cardiovascular symptoms improvement after deep brain stimulation in patients with Parkinson's disease: a systematic review

BACKGROUND

Autonomic dysfunction is common and disabling in Parkinson's disease (PD). The effects of deep brain stimulation (DBS) on the cardiovascular system in PD remain poorly understood. We aimed to assess the effect of DBS on cardiovascular symptoms and objective measures in PD patients.

METHODS

We conducted a systematic literature search in PubMed/MEDLINE.

RESULTS

36 out of 472 studies were included, mostly involving DBS of the subthalamic nucleus, and to a lesser extent the globus pallidus pars interna and pedunculopontine nucleus. Seventeen studies evaluated the effect of DBS on patient-reported or clinician-rated cardiovascular symptoms, showing an improvement in the first year after surgery but not with longer-term follow-up. DBS has no clear direct effects on blood pressure during an orthostatic challenge (n = 10 studies). DBS has inconsistent effects on heart rate variability (n = 10 studies).

CONCLUSION

Current evidence on the impact of DBS on cardiovascular functions in PD is inconclusive. DBS may offer short-term improvement of cardiovascular symptoms in PD, particularly orthostatic hypotension, which may be attributed to dopaminergic medication reduction after surgery. There is insufficient evidence to draw conclusions on the direct effect of DBS on blood pressure and heart rate variability.

Salidroside improves cognitive function in Parkinson's disease via Braf-mediated mitogen‑activated protein kinase signaling pathway

OBJECTIVE

To delve into the underlying mechanism of Salidroside (Sal) on the improvement of cognitive function in Parkinson's Disease (PD).

METHODS

The experimental mice were divided into Control group, Model group [injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)], and Model+Sal (low concentration, high concentration) group. Mouse hippocampal tissues were extracted for RNA sequencing to obtain the core pathway and core gene. Mouse plasma was prepared and analyzed by LC-MS to obtain differential metabolites. In vitro experiments were verified by immunofluorescence and lentiviral transduction.

RESULTS

ELISA signaled that Sal facilitated the reduction of neuronal damage and inflammatory reaction in mice. MPTP_Sal_Low and MPTP_Sal_High groups had high levels of glial cell derived neurotrophie factor (GDNF) expression. Differentially expressed genes (DEGs) in control group, MPTP group and MPTP_Sal_High group were identified by transcriptomic, which were classified to the mitogen-activated protein kinase (MAPK) signaling pathway, and the core gene Braf was obtained. Metabolomics manifested that the differential metabolites involved DL-tyrosine, adenosine, phosphoenolpyruvate, and L-tryptophan. In vitro experiments verified that Sal treatment inhibited the up-regulation of p-p38, p-c-Jun N-terminal kinase (JNK), and p-extracellular signal-regulated kinase (ERK) expression, and growth of neuronal protrusions. The OE-Braf group showed a significant up-regulation of the GDNF expression, a decrease in the expression of p-p38, p-JNK, and p-ERK, and a significant growth of neuronal protrusions.

CONCLUSION

Sal may exert its effects in PD through the Braf-mediated MAPK signaling pathway, which can increase GDNF expression and promote neuronal protrusion growth for the protection of neurological function and the improvement of cognitive function.

Abnormal Cerebrovascular Activity, Perfusion, and Glymphatic Clearance in Lewy Body Diseases

Cerebrovascular activity is not only crucial to optimal cerebral perfusion, but also plays an important role in the glymphatic clearance of interstitial waste, including α-synuclein. This highlights a need to evaluate how cerebrovascular activity is altered in Lewy body diseases. This review begins by discussing how vascular risk factors and cardiovascular autonomic dysfunction may serve as upstream or direct influences on cerebrovascular activity. We then discuss how patients with Lewy body disease exhibit reduced and delayed cerebrovascular activity, hypoperfusion, and reductions in measures used to capture cerebrospinal fluid flow, suggestive of a reduced capacity for glymphatic clearance. Given the lack of an existing framework, we propose a model by which these processes may foster α-synuclein aggregation and neuroinflammation. Importantly, this review highlights several avenues for future research that may lead to treatments early in the disease course, prior to neurodegeneration. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

A pilot dose-finding study of Terazosin in humans

Background

Parkinson's disease (PD) is a prevalent neurodegenerative disorder where progressive neuron loss is driven by impaired brain bioenergetics, particularly mitochondrial dysfunction and disrupted cellular respiration. Terazosin (TZ), an α-1 adrenergic receptor antagonist with a known efficacy in treating benign prostatic hypertrophy and hypertension, has shown potential in addressing energy metabolism deficits associated with PD due to its action on phosphoglycerate kinase 1 (PGK1). This study aimed to investigate the safety, tolerability, bioenergetic target engagement, and optimal dose of TZ in neurologically healthy subjects.

Methods

Eighteen healthy men and women (60 - 85 years old) were stratified into two cohorts based on maximum TZ dosages (5 mg and 10 mg daily). Methods included plasma and cerebrospinal fluid TZ concentration measurements, whole blood ATP levels, 31 Phosphorous magnetic resonance spectroscopy for brain ATP levels, 18 F-FDG PET imaging for cerebral metabolic activity, and plasma metabolomics.

Results

Our results indicated that a 5 mg/day dose of TZ significantly increased whole blood ATP levels and reduced global cerebral 18 F-FDG PET uptake without significant side effects or orthostatic hypotension. These effects were consistent across sexes. Higher doses did not result in additional benefits and showed a potential biphasic dose-response.

Conclusions

TZ at a dosage of 5 mg/day engages its metabolic targets effectively in both sexes without inducing significant adverse effects and provides a promising therapeutic avenue for mitigating energetic deficiencies. Further investigation via clinical trials to validate TZ's efficacy and safety in neurodegenerative (i.e., PD) contexts is warranted.

The relationship between oxidative balance score and erectile dysfunction in the U.S. male adult population

Oxidative stress strongly influences the pathophysiology of erectile dysfunction (ED). In this study, we used the oxidative balance score (OBS), a composite index, to measure the effects of oxidative stress triggered by diet and lifestyle factors. Here, we conducted a cross-sectional study to determine the statistical relationship between OBS and ED among adult males in the U.S. The data from 3318 participants in the National Health and Nutrition Examination Survey (NHANES) 2001-2004 were analyzed. Weighted logistic regression was used to correct for confounding factors and acquire nationwide representative estimates. Generalized additive modeling was used to explore the nonlinear relationship. We also supplemented subgroup and sensitivity analysis to examine the robustness of the main results. Multivariate logistic regression indicated a consistent negative linear association between OBS and ED across all participants [OR (95% CI) = 0.96 (0.94, 0.98)]. After categorizing OBS into tertiles, participants in the highest tertile had 43% lower odds of having ED than those in the lowest tertile [OR (95% CI) = 0.57 (0.37, 0.87)]. The generalized additive model also visualized the linear trend of this association. Furthermore, this linear relationship remained relatively consistent, regardless of whether subgroup or sensitivity analyses were performed. Our findings suggest that adopting a lifestyle and diet pattern that promotes favorable OBS may effectively protect against the development of ED, regardless of the underlying causes.

The Relationship Between Autonomic Dysfunction and Mood Symptoms in De Novo Parkinson's Disease Patients Over Time

BACKGROUND

Autonomic dysfunction is prevalent in Parkinson's disease (PD) and can worsen quality of life. We examined: (a) whether specific autonomic symptoms were more strongly associated with anxiety or depression in PD and (b) whether overall autonomic dysfunction predicted mood trajectories over a 5-year period.

METHODS

Newly diagnosed individuals with PD (N = 414) from the Parkinson's Progression Markers Initiative completed self-report measures of depression, anxiety, and autonomic symptoms annually. Cross-sectional linear regressions examined relationships between specific autonomic subdomains (gastrointestinal, cardiovascular, thermoregulatory, etc.) and mood. Multilevel modeling examined longitudinal relationships with total autonomic load.

RESULTS

Gastrointestinal symptoms were associated with both higher anxiety (b = 1.04, 95% CI [.55, 1.53], P < .001) and depression (b = .24, 95% CI [.11, .37], P = .012), as were thermoregulatory symptoms (anxiety: b = 1.06, 95% CI [.46, 1.65], P = .004; depression: b = .25, 95% CI [.09, .42], P = .013), while cardiovascular (b = .36, 95% CI [.10, .62], P = .012) and urinary symptoms (b = .10, 95% CI [.01, .20], P = .037) were associated only with depression. Longitudinally, higher total autonomic load was associated with increases in both depression (b = .01, 95% CI [.00, .02], P = .015) and anxiety (b = .04, 95% CI [.01, .06], P < .001) over time, as well as occasion-to-occasion fluctuations (depression: b = .08, 95% CI [.05, .10], P < .001; anxiety: b = .24, 95% CI [.15, .32], P < .001).

CONCLUSION

Findings suggest autonomic dysfunction, particularly gastrointestinal and thermoregulatory symptoms, may be an indicator for elevated anxiety/depression and a potential treatment target early on in PD.

Non-motor symptoms associated with progressive loss of dopaminergic neurons in a mouse model of Parkinson's disease

Parkinson's disease (PD) is characterized by three main motor symptoms: bradykinesia, rigidity and tremor. PD is also associated with diverse non-motor symptoms that may develop in parallel or precede motor dysfunctions, ranging from autonomic system dysfunctions and impaired sensory perception to cognitive deficits and depression. Here, we examine the role of the progressive loss of dopaminergic transmission in behaviors related to the non-motor symptoms of PD in a mouse model of the disease (the TIF-IADATCreERT2 strain). We found that in the period from 5 to 12 weeks after the induction of a gradual loss of dopaminergic neurons, mild motor symptoms became detectable, including changes in the distance between paws while standing as well as the swing speed and step sequence. Male mutant mice showed no apparent changes in olfactory acuity, no anhedonia-like behaviors, and normal learning in an instrumental task; however, a pronounced increase in the number of operant responses performed was noted. Similarly, female mice with progressive dopaminergic neuron degeneration showed normal learning in the probabilistic reversal learning task and no loss of sweet-taste preference, but again, a robustly higher number of choices were performed in the task. In both males and females, the higher number of instrumental responses did not affect the accuracy or the fraction of rewarded responses. Taken together, these data reveal discrete, dopamine-dependent non-motor symptoms that emerge in the early stages of dopaminergic neuron degeneration.

Association between bowel movement frequency and erectile dysfunction in patients with ulcerative colitis: a cross-sectional study

The association between ulcerative colitis (UC) and erectile dysfunction (ED) has been previously reported. Numerous previous studies have also reported an association between gastrointestinal symptoms and ED. Constipation and diarrhea are common in patients with UC. However, the specific association between bowel movement frequency and ED remains unclear. The aim of this study is to investigate the association between bowel movement frequency and ED in 164 patients with UC. The definition of ED, moderate to severe ED, and severe ED was the Sexual Health Inventory for Men score <22, <12, and <8, respectively. Bowel movement frequency was divided into three categories: (1) high (More than once a day), (2) normal (once a day, reference), and low (less than one time/day). The definition of constipation was based on the Rome I criteria and/or medication for constipation. The prevalence of constipation and ED was 10.4% and 86.0%, respectively. The rate of high, normal, and low bowel movement frequency was 56.1%, 25.0%, and 18.9%, respectively. High bowel movement frequency was independently and positively associated with ED and moderate to severe ED (ED: adjusted odds ratio [OR] 4.42, 95% confidence interval [CI] 1.35-15.98; moderate to severe: adjusted OR 2.98, 95% CI 1.22-7.61). Low bowel movement frequency was independently and positively associated with moderate to severe ED and severe ED (moderate to severe: adjusted OR 3.96, 95% CI 1.27-13.08; severe: adjusted OR 3.20, 95% CI 1.08-9.86). No association between constipation and ED was found. In conclusion, in Japanese patients with UC, both high and low bowel movement frequency were independently and positively associated with ED.

Deficiency of polypeptide N-acetylgalactosamine transferase 9 contributes to a risk for Parkinson's disease via mitochondrial dysfunctions

Polypeptide N-acetylgalactosamine transferase 9 (GALNT9) catalyzes the initial step of mucin-type O-glycosylation via linking N-acetylgalactosamine (GalNAc) to serine/threonine in a protein. To unravel the association of GALNT9 with Parkinson's disease (PD), a progressive neurodegenerative disorder, GALNT9 levels were evaluated in the patients with PD and mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and statistically analyzed based on the GEO datasets of GSE114918 and GSE216281. Glycoproteins with exposing GalNAc were purified using lectin affinity chromatography and identified by LC-MS/MS. The influence of GALNT9 on cells was evaluated via introducing a GALNT9-specific siRNA into SH-SY5Y cells. Consequently, GALNT9 deficiency was found to occur under PD conditions. GALNT9 silencing contributed to a causative factor in PD pathogenesis via reducing the levels of intracellular dopamine, tyrosine hydroxylase and soluble α-synuclein, and promoting α-synuclein aggregates. MS identification revealed 14 glycoproteins. 5 glycoproteins, including ACO2, ATP5B, CKB, CKMT1A, ALDOC, were associated with energy metabolism. GALNT9 silencing resulted in mitochondrial dysfunctions via increasing ROS accumulation, mitochondrial membrane depolarization, mPTPs opening, Ca2+ releasing and activation of the CytC-related apoptotic pathway. The dysfunctional mitochondria then triggered mitophagy, possibly intermediated by adenine nucleotide translocase 1. Our study suggests that GALNT9 is potentially developed into an auxiliary diagnostic index and therapeutic target of PD.

Effectiveness and safety of different catechol-o-methyl transferase inhibitors for patients with parkinson's disease: Systematic review and network meta-analysis

BACKGROUND

Levodopa treatment requires the addition of other drugs, such as catechol-O-methyl transferase (COMT) inhibitors, to alleviate motor fluctuations in advanced parkinson's disease (PD). However, the optimal strategy, including the type and dose of COMT inhibitors remains unknown. This systematic review and network meta-analysis aimed to assess the efficacy and safety of different COMT inhibitors and for treating PD patients.

METHODS

PubMed, Embase, Cochrane Library and Web of Science were screened up to November 20, 2022. Randomized controlled trials (RCTs) of COMT inhibitors (entacapone, opicapone, tolcapone) for PD patients were included. Eligible outcomes were total ON-time, rate of ON-time >1 h, total daily dose of levodopa therapy, mean change from baseline to final follow up in Unified Parkinson's Disease Rating Scale (UPDRS) part III scores, adverse events and dyskinesia. Network meta-analyses integrated direct and indirect evidence with placebo as a common comparator.

RESULTS

We identified 18 studies with 7564 patients. Opicapone, entacapone, and tolcapone could increase total ON-time when compared with placebo. However, opicapone (25 mg, MD 4.0, 95%CrI: 1.1-7.5) and opicapone (50 mg, MD 5.1, 95%CrI: 2.2-8.7) statistically significant increase the total ON-time. opicapone and entacapone could increase the rate of ON-time >1 h when compared with placebo. Only opicapone (5 mg) showed no statistically significant with placebo (OR 1.4, 95%CrI: 0.74-2.4). We found that opicapone (50 mg, SURCA, 0.796) is the best option compared with other treatments. TOL (200 mg) was ranked highest in the rank probability test for total daily dose of levodopa therapy, followed by OPI (50 mg), TOL (400 mg) and TOL (100 mg) in order. SUCRA rankings identified TOL (200 mg) as the most likely therapy for increasing adverse events (SUCRA 27.19%), followed by TOL (400 mg, SUCRA 27.20%) and OPI (5 mg, SUCRA 30.81%). The SUCRA probabilities were 91.6%, 75.2%, 67.9%, 59.3%, 45.6%, 41.1%, 35.1%, 24.6% and 9.4% for PLA, TOL (400 mg), ENT (100 mg), ENT (200 mg), OPI (5 mg), TOL (100 mg), OPI (25 mg), OPI (50 mg), and TOL (200 mg) respectively.

CONCLUSION

In conclusion, opicapone (50 mg) may be a better choice for treatment PD when compared with other COMT inhibitors.

Neuroimmune Connectomes in the Gut and Their Implications in Parkinson's Disease

The gastrointestinal tract is the largest immune organ and it receives dense innervation from intrinsic (enteric) and extrinsic (sympathetic, parasympathetic, and somatosensory) neurons. The immune and neural systems of the gut communicate with each other and their interactions shape gut defensive mechanisms and neural-controlled gut functions such as motility and secretion. Changes in neuroimmune interactions play central roles in the pathogenesis of diseases such as Parkinson's disease (PD), which is a multicentric disorder that is heterogeneous in its manifestation and pathogenesis. Non-motor and premotor symptoms of PD are common in the gastrointestinal tract and the gut is considered a potential initiation site for PD in some cases. How the enteric nervous system and neuroimmune signaling contribute to PD disease progression is an emerging area of interest. This review focuses on intestinal neuroimmune loops such as the neuroepithelial unit, enteric glial cells and their immunomodulatory effects, anti-inflammatory cholinergic signaling and the relationship between myenteric neurons and muscularis macrophages, and the role of α-synuclein in gut immunity. Special consideration is given to the discussion of intestinal neuroimmune connectomes during PD and their possible implications for various aspects of the disease.

Significance of non-motor symptoms and development of a screening tool for osteoporosis in Parkinson's disease

BACKGROUND AND PURPOSE

Parkinson's disease (PD) patients have a higher likelihood of having osteoporosis compared to controls, therefore deserving special attention. This study was to 1) investigate the association of non-motor symptoms with osteoporosis amongst PD patients, and 2) develop screening tools for osteoporosis.

MATERIALS AND METHODS

PD Patients were included (n = 109). The factors/variables were obtained from clinical records due to the retrospective nature of this study. The bone mineral density (BMD) of the lumbar spine and femoral neck was examined using a dual-energy X-ray absorptiometry machine, according to which they were categorized as either having (T-score ≤ -2.5) or not having osteoporosis (T-score>-2.5) at the two sites. The non-motor symptoms were assessed using clinical scales, including non-motor experiences of daily living, depression, anxiety, cognitive function, and autonomic function. The potential covariates included demographic and clinical factors/variables, such as age and sex. Logistic regression was used to investigate the associations and establish the screening tools.

RESULTS

Patients with autonomic dysfunction had significantly (p = 0.011) higher odds of having femoral neck osteoporosis compared to those with no/minimal dysfunction after adjusting for sex, disease duration, and body mass index, demonstrating a strong association (odds ratio=12.81). Based on the four factors/variables, a screening tool with a good accuracy was established (C-statistic = 0.85).

CONCLUSION

PD patients with autonomic dysfunction had greater odds of having femoral neck osteoporosis compared to those with no/minimal dysfunction. The screening tool may lay a foundation for developing screening models with higher accuracy to identify which PD patients may require a BMD test.

Corneal confocal microscopy may help to distinguish Multiple System Atrophy from Parkinson's disease

Multiple system atrophy (MSA) and Parkinson's disease (PD) have clinical overlapping symptoms, which makes differential diagnosis difficult. Our research aimed to distinguish MSA from PD using corneal confocal microscopy (CCM), a noninvasive and objective test. The study included 63 PD patients, 30 MSA patients, and 31 healthy controls (HC). When recruiting PD and MSA, questionnaires were conducted on motor and non-motor functions, such as autonomic and cognitive functions. Participants underwent CCM to quantify the corneal nerve fibers. Corneal nerve fiber density (CNFD) and corneal nerve fiber length (CNFL) values in MSA are lower than PD (MSA vs. PD: CNFD, 20.68 ± 6.70 vs. 24.64 ± 6.43 no./mm2, p < 0.05; CNFL, 12.01 ± 3.25 vs. 14.17 ± 3.52 no./mm2, p < 0.05). In MSA + PD (combined), there is a negative correlation between CNFD and the Orthostatic Grading Scale (OGS) (r = -0.284, p = 0.007). Similarly, CNFD in the only MSA group was negatively correlated with the Unified Multiple System Atrophy Rating Scale I and II (r = -0.391, p = 0.044; r = -0.382, p = 0.049). CNFD and CNFL were inversely associated with MSA (CNFD: β = -0.071; OR, 0.932; 95% CI, 0.872 ~ 0.996; p = 0.038; CNFL: β = -0.135; OR, 0.874; 95% CI, 0.768-0.994; p = 0.040). Furthermore, we found the area under the receiver operating characteristic curve (ROC) of CNFL was the largest, 72.01%. The CCM could be an objective and sensitive biomarker to distinguish MSA from PD. It visually reflects a more severe degeneration in MSA compared to PD.

Clinical characteristics of patients with Parkinson's disease with reduced 123I-metaiodobenzylguanidine uptake in the major salivary glands and heart

BACKGROUND

Parkinson's disease (PD) shows cardiac sympathetic denervation (SD) in 123I-metaiodobezylguanidine (MIBG) scintigraphy. Recently, SD in the major salivary glands (MSG-SD) was introduced as a possible radiological feature of PD.

OBJECTIVE

To identify the clinical characteristics of patients with PD with reduced MSG and cardiac MIBG uptake (dual-SD) compared with those with reduced MSG or cardiac MIBG uptake only (single-SD).

METHODS

We recruited 90 patients with PD and 30 controls and evaluated their non-motor (e.g., hyposmia, autonomic dysfunction) and motor (e.g., Movement Disorder Society-Unified Parkinson's Disease Rating Scale) features. We also assessed MIBG uptake in the MSG and heart using a quantitative semi-automatic method, and compared MIBG uptakes between PD and controls. We set cut-off values for optimal sensitivity and specificity, and compared the clinical characteristics of patients with PD between dual- and single-SD groups.

RESULTS

MSG and cardiac MIBG uptakes were significantly reduced in PD. Sixty-one patients had dual-SD, 25 had single-SD, and four had non-SD. In patients with PD with normal cardiac SD, 76.5% (13/17) of whom showed abnormalities only in MSG-SD. When clinical characteristics were compared between the dual-SD and single-/non-SD groups, patients in the dual-SD group were older and had more severe hyposmia and autonomic dysfunction, except motor features. Multiple logistic regression analysis identified age as an important confounder.

CONCLUSIONS

Patients with PD with dual-SD have more severe non-motor features than other patients. Autonomic dysfunction might progress independently from dopaminergic degeneration. Furthermore, our findings indicate that aging is a crucial factor in PD progression.

Monitoring autonomic responses in Parkinson's disease individuals: non-linear and chaotic global metrics of heart rate variability

AIM

To examine and compare the autonomic responses, as assessed through the non-linear and chaotic global metrics of heart rate variability in two groups: the Parkinson's Disease Group (PDG) and the Control Group (CG), both at rest and during an active tilt test.

METHODS

The study encompassed 46 participants (PDG: n = 23; 73.73 ± 7.28 years old; CG: n = 23; 70.17 ± 8.20 years old). Initial data collection involved the acquisition of participant's characteristics. The autonomic modulation was estimated both at rest and during the active tilt test. For this assessment, we computed non-linear indices derived from five entropies (Approximate, Sample, Shannon, Renyi, Tsallis), Detrended Fluctuation Analysis and the seven chaotic global metrics (hsCFP1-hsCFP7).

RESULTS

At rest, the PDG exhibited lower values of hsCFP3 (0.818 ± 0.116 vs. 0.904 ± 0.065; p < 0.05) and Sample Entropy (0.720 ± 0.149 vs. 0.799 ± 0.171; p < 0.05). During the test, the PDG demonstrated lower values of ApEn, while the CG presented lower values of SampEn, hsCFP1, hsCFP3, hsCFP7, and higher values of hsCFP5. An interaction was observed, indicating that hsCFP1 and hsCFP3 exhibit differential behavior for the CG and PDG in response to the test.

CONCLUSION

subjects with PD exhibited reduced complexity of the RR interval series at rest, and a diminished autonomic response to the active tilt test when compared with the CG. The test, together with non-linear indices, may serve for assessing the Autonomic Nervous System in individuals with PD in a clinical setting. The interpretation of these data should be approached with caution, given the possible influences of pharmacotherapies and the inclusion of diabetic participants.

Machine-learning model for the prediction of acute orthostatic hypotension after levodopa administration

BACKGROUND

Levodopa could induce orthostatic hypotension (OH) in Parkinson's disease (PD) patients. Accurate prediction of acute OH post levodopa (AOHPL) is important for rational drug use in PD patients. Here, we develop and validate a prediction model of AOHPL to facilitate physicians in identifying patients at higher probability of developing AOHPL.

METHODS

The study involved 497 PD inpatients who underwent a levodopa challenge test (LCT) and the supine-to-standing test (STS) four times during LCT. Patients were divided into two groups based on whether OH occurred during levodopa effectiveness (AOHPL) or not (non-AOHPL). The dataset was randomly split into training (80%) and independent test data (20%). Several models were trained and compared for discrimination between AOHPL and non-AOHPL. Final model was evaluated on independent test data. Shapley additive explanations (SHAP) values were employed to reveal how variables explain specific predictions for given observations in the independent test data.

RESULTS

We included 180 PD patients without AOHPL and 194 PD patients with AOHPL to develop and validate predictive models. Random Forest was selected as our final model as its leave-one-out cross validation performance [AUC_ROC 0.776, accuracy 73.6%, sensitivity 71.6%, specificity 75.7%] outperformed other models. The most crucial features in this predictive model were the maximal SBP drop and DBP drop of STS before medication (ΔSBP/ΔDBP). We achieved a prediction accuracy of 72% on independent test data. ΔSBP, ΔDBP, and standing mean artery pressure were the top three variables that contributed most to the predictions across all individual observations in the independent test data.

CONCLUSIONS

The validated classifier could serve as a valuable tool for clinicians, offering the probability of a patient developing AOHPL at an early stage. This supports clinical decision-making, potentially enhancing the quality of life for PD patients.

Emerging wearable technologies for multisystem monitoring and treatment of Parkinson's disease: a narrative review

Parkinson's disease (PD) is a chronic movement disorder characterized by a variety of motor and nonmotor comorbidities, including cognitive impairment, gastrointestinal (GI) dysfunction, and autonomic/sleep disturbances. Symptoms typically fluctuate with different settings and environmental factors and thus need to be consistently monitored. Current methods, however, rely on infrequent rating scales performed in clinic. The advent of wearable technologies presents a new avenue to track objective measures of PD comorbidities longitudinally and more frequently. This narrative review discusses and proposes emerging wearable technologies that can monitor manifestations of motor, cognitive, GI, and autonomic/sleep comorbidities throughout the daily lives of PD individuals. This can provide more wholistic insight into real-time physiological versus pathological function with the potential to better assess treatments during clinical trials and allow physicians to optimize treatment regimens. Additionally, this narrative review briefly examines novel applications of wearables as therapy for PD patients.

Orally administered neohesperidin attenuates MPTP-induced neurodegeneration by inhibiting inflammatory responses and regulating intestinal flora in mice

Parkinson's disease (PD), a neurodegenerative disease, is the leading cause of movement disorders. Neuroinflammation plays a critical role in PD pathogenesis. Neohesperidin (Neo), a natural flavonoid extracted from citric fruits exhibits anti-inflammatory effects. However, the effect of Neo on PD progression is unclear. This study aimed to investigate the effects of Neo on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD in mice and its underlying mechanism. Our results indicated that Neo administration ameliorated motor impairment and neural damage in MPTP-injected mice, by inhibiting neuroinflammation and regulating gut microbial imbalance. Additionally, Neo administration reduced colonic inflammation and tissue damage. Mechanistic studies revealed that Neo suppressed the MPTP-induced inflammatory response by inhibiting excessive activation of NF-κB and MAPK pathways. In summary, the present study demonstrated that Neo administration attenuates neurodegeneration in MPTP-injected mice by inhibiting inflammatory responses and regulating the gut microbial composition. This study may provide the scientific basis for the use of Neo in the treatment of PD and other related diseases.

Alterations in descending brain-spinal pathways regulating colorectal motility in a rat model of Parkinson's disease

Patients with Parkinson's disease (PD) often have constipation. It is assumed that a disorder of the regulatory mechanism of colorectal motility by the central nervous system is involved in the constipation, but this remains unclear. The aim of this study was to investigate whether central neural pathways can modulate colorectal motility in a rat model of PD. PD model rats were generated by injection of 6-hydroxydopamine into a unilateral medial forebrain bundle and destruction of dopaminergic neurons in the substantia nigra. Colorectal motility was measured in vivo in anesthetized rats. Intraluminal administration of capsaicin, as a noxious stimulus, induced colorectal motility in sham-operated rats but not in PD rats. Intrathecally administered dopamine (DA) and serotonin (5-HT), which mediate the prokinetic effect of capsaicin, at the L6-S1 levels enhanced colorectal motility in PD rats similarly to that in sham-operated rats. In PD rats, capsaicin enhanced colorectal motility only when a GABAA receptor antagonist was preadministered into the lumbosacral spinal cord. Capsaicin-induced colorectal motility was abolished by intrathecal administration of a D2-like receptor antagonist but not by administration of 5-HT2 and 5-HT3 receptor antagonists. These findings demonstrate that the inhibitory GABAergic component becomes operative and the stimulatory serotonergic component is suppressed in PD rats. The alteration of the central regulatory mechanism of colorectal motility is thought to be related to the occurrence of constipation in PD patients. Our findings provide a new insight into the pathogenesis of defecation disorders observed in PD.NEW & NOTEWORTHY In a rat model of Parkinson's disease, the component of descending brain-spinal pathways that regulate colorectal motility through a mediation of the lumbosacral defecation center was altered from stimulatory serotonergic neurons to inhibitory GABAergic neurons. Our findings suggest that chronic constipation in Parkinson's disease patients may be associated with alterations in central regulatory mechanisms of colorectal motility. The plasticity in the descending pathway regulating colorectal motility may contribute to other disease-related defecation abnormalities.

Identification of Key Genes and Immunological Features Associated with Copper Metabolism in Parkinson's Disease by Bioinformatics Analysis

To explore diagnostic genes associated with cuproptosis in Parkinson's disease (PD) and to characterize immune cell infiltration by comprehensive bioinformatics analysis, three PD datasets were downloaded from the GEO database, two of which were merged and preprocessed as the internal training set and the remaining one as the external validation set. Based on the internal training set, differential analysis was performed to obtain differentially expressed genes (DEGs), and weighted gene co-expression network analysis (WGCNA) was conducted to obtain significant module genes. The genes obtained here were intersected to form the intersecting genes. The intersecting genes obtained from DEGs and WGCNA were intersected with cuproptosis-related genes (CRGs) to generate cuproptosis-related disease signature genes, and functional enrichment analysis was performed on Disease Ontology (DO), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, LASSO analysis of the cuproptosis-related disease signature genes was performed to identify key genes and construct a diagnostic and predictive model. Then, single sample gene set enrichment analysis (ssGSEA) was performed on the internal training set to further analyze the correlation between key genes and immune cells. Lastly, the results were validated using an external validation set. A total of 405 DEGs were obtained by differential analysis, and 6 gene modules were identified by WGCNA analysis. The genes in the most significant modules were intersected with the DEGs to obtain 21 intersecting genes. The functions of the intersecting genes were mainly enriched in neurotransmitter transport, GABA-ergic synapse, synaptic vesicle cycle, serotonergic synapse, phenylalanine metabolism, tyrosine metabolism, tryptophan metabolism, etc. Subsequently, the intersecting genes were intersected with CRGs, and LASSO regression analysis was performed to screen 3 key cuproptosis-related disease signature genes, namely, SLC18A2, SLC6A3, and SV2C. The calibration curve of the nomogram model constructed based on these 3 key genes to predict PD showed good agreement, with a C-index of 0.944 and an area under the ROC (AUC) of 0.944 (0.833-1.000). It was also validated by the external dataset that the model constructed with these 3 key genes had good diagnostic and predictive power for PD. The ssGSEA analysis revealed that neutrophils might be the potential core immune cells and that SLC18A2, SLC6A3, and SV2C were significantly negatively correlated with neutrophils, which was also verified in the validation set. PD diagnosis and prediction model based on CRGs (SLC18A2, SLC6A3, and SV2C) has good diagnostic and predictive performance and could be a useful tool in the diagnosis of PD.

Therapeutic effects of saffron and its components on neurodegenerative diseases

Due to an increase in the number of older people in recent years, neurodegenerative diseases as the most important age-related neurological disorders are considered as a great threat to human health. The treatment strategies for these disorders are symptomatic and there is no known definitive treatment; however, recently, several studies have investigated the effectiveness of some herbs and their components in limiting the progression and treatment of neurodegenerative disorders. In this study, we searched Medline (via PubMed), Scopus, Science Direct, and Google Scholar databases. The keywords used in the search were: saffron [title/abstract] or (saffron compound [title/abstract]) and (neurological disorders [title/abstract]), publication date range (2010-2023), and language (English). After applying inclusion and exclusion criteria, 30 articles remained. Of the 30 articles included in the study, six studies on the treatment of neurodegenerative disorders by saffron and its components were in the clinical trial phase, and 24 studies were in the preclinical phase. Saffron and its compounds can play an important role in inhibiting neuroinflammation and excitotoxic pathways, modulating autophagy and apoptosis, attenuating oxidative damage, and activating defensive antioxidant enzymes, resulting in neuroprotection against neurodegenerative diseases. Therefore, this study aimed to review the studies on the effects of saffron and its compounds on the treatment of neurodegenerative diseases.

Research progress on the cannabinoid type-2 receptor and Parkinson's disease

Parkinson's disease (PD) is featured by movement impairments, including tremors, bradykinesia, muscle stiffness, and imbalance. PD is also associated with many non-motor symptoms, such as cognitive impairments, dementia, and mental disorders. Previous studies identify the associations between PD progression and factors such as α-synuclein aggregation, mitochondrial dysfunction, inflammation, and cell death. The cannabinoid type-2 receptor (CB2 receptor) is a transmembrane G-protein-coupled receptor and has been extensively studied as part of the endocannabinoid system. CB2 receptor is recently emerged as a promising target for anti-inflammatory treatment for neurodegenerative diseases. It is reported to modulate mitochondrial function, oxidative stress, iron transport, and neuroinflammation that contribute to neuronal cell death. Additionally, CB2 receptor possesses the potential to provide feedback on electrophysiological processes, offering new possibilities for PD treatment. This review summarized the mechanisms underlying PD pathogenesis. We also discussed the potential regulatory role played by CB2 receptor in PD.

Effects of a Concurrent Working Memory Task on Speech Acoustics in Parkinson's Disease

PURPOSE

The purpose of this study was to determine the effect of a concurrent working memory task on acoustic measures of speech in individuals with Parkinson's disease (PD).

METHOD

Individuals with PD and age- and sex-matched controls performed a speaking task with and without a Stroop-like concurrent working memory task. Cepstral peak prominence, low-to-high spectral energy ratio, fundamental frequency (fo) standard deviation, articulation rate, pause duration, articulatory-acoustic vowel space, relative fo, mean voice onset time (VOT), and VOT variability were calculated for each condition. Mixed-model analyses of variance were performed to determine the effects of group, condition (presence of the concurrent working memory task), and their interaction on the acoustic measures.

RESULTS

All measures except for VOT variability, mean pause duration, and relative fo offset differed between people with and without PD. Cepstral peak prominence, articulation rate, and relative fo offset differed as a function of condition. However, no measures indicated disparate effects of condition as a function of group.

CONCLUSION

Although differentially impactful on limb motor function in PD, here a concurrent working memory task was not found to be differentially disruptive to speech acoustics in PD.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24759648.

The gut-brain axis in Parkinson's disease

There is a bi-directional communication between the gut, including the microbiota, and the brain through the autonomic nervous system. Accumulating evidence has suggested a bidirectional link between gastrointestinal inflammation and neurodegeneration, in accordance with the concept of the gut-rain axis. An abnormal microbiota-gut-brain interaction contributes to the pathogeny of Parkinson's disease. This supports the hypothesis that Parkinson's disease originates in the gut to spread to the central nervous system, in particular through the vagus nerve. Targeting the gut-to-brain axis with vagus nerve stimulation, fecal microbiota transplantation, gut-selective antibiotics, as well as drugs targeting the leaky gut might be of interest in the management of Parkinson's disease.

Non-Motor Symptom Management: Insights into Adherence to Treatment Guidelines in Parkinson's Disease Patients

Background

Non-motor symptoms (NMS) reduce quality of life in Parkinson's disease (PD) patients, who experience three times more NMS than individuals without PD. While there are international and national NMS treatment guidelines, their implication in clinical practice remains unclear.

Objective

This study aimed to investigate the adherence to pharmacological NMS treatment guidelines in patients with mild to moderately severe PD.

Methods

220 PD patients with ≥1 NMS based on the Non-Motor Symptom Questionnaire and a Hoehn and Yahr stage ≤4 were randomly selected from the Swedish Parkinson registry and screened for inclusion. NMS were evaluated using the International Parkinson and Movement Disorder Society-Non-Motor Rating Scale (MDS-NMS), Parkinson's Disease Sleep Scale 2, Epworth Sleepiness Scale, and Hospital Anxiety and Depression Scale. Treatment was compared with Swedish national guidelines and international guidelines from the MDS Evidence-Based Medicine Committee.

Results

Among 165 included patients, the median number of NMS was 14, and in median 7 symptoms were estimated to require treatment. The most common NMS requiring treatment were pain (69%) and urinary problems (56%). Treatment of depression and constipation demonstrated the highest adherence to guidelines (79% and 77%), while dysphagia and excessive daytime sleepiness exhibited the lowest adherence (0% and 4%). On average, only 32% of NMS were treated in accordance with guidelines.

Conclusions

Adherence to pharmacological guidelines for NMS in patients with mild to severe PD was low. This study highlights the need for improved evaluation and treatment of NMS to enhance symptom management and quality of life among PD patients.

Effects of Blood Flow Restriction Resistance Training on Autonomic and Endothelial Function in Persons with Parkinson's Disease

Background

Autonomic dysfunction precedes endothelial dysfunction in Parkinson's disease (PD) and causes blood pressure and circulation abnormalities that are highly disruptive to one's quality of life. While exercise interventions have proven helpful for motor symptoms of PD, improving associated non-motor symptoms is limited. Low-intensity resistance training with blood flow restriction (LIRT-BFR) improves autonomic dysfunction in non-PD patients and high-intensity resistance training (HIRT) is recommended for motor symptom improvements for people with PD (PwPD).

Objective

To determine the effects of LIRT-BFR and HIRT on homocysteine and autonomic and endothelial function in PwPD and to determine the hemodynamic loads during LIRT-BFR and HIRT in PwPD using a novel exercise protocol.

Methods

Thirty-eight PwPD were assigned LIRT-BFR, HIRT or to a control (CNTRL) group. The LIRT-BFR and HIRT groups exercised three days per week for four weeks. The LIRT-BFR protocol used 60% limb occlusion pressure (LOP) and performed three sets of 20 repetitions at 20% of the one-repetition maximum (1RM). The HIRT group performed three sets of eight repetitions at 80% 1RM. The CNTRL group was asked to continue their normal daily routines.

Results

LIRT-BFR significantly improved orthostatic hypotension (p = 0.026), homocysteine levels (p < 0.001), peripheral circulation (p = 0.003), supine blood pressure (p = 0.028) and heart rate variability (p = 0.041); LIRT-BFR improved homocysteine levels (p < 0.018), peripheral circulation (p = 0.005), supine blood pressure (p = 0.007) and heart rate variability (p = 0.047) more than HIRT; and hemodynamic loads for LIRT-BFR and HIRT were similar.

Conclusions

LIRT-BFR may be more effective than HIRT for autonomic and endothelial function improvements in PwPD and hemodynamic loads may be lessened in LIRT-BFR protocols using single-joint exercises with intermittent blood flow restriction. Further research is needed to determine if non-motor symptoms improve over time and if results are sustainable.

Effects of curcumin to counteract levodopa-induced toxicity in zebrafish

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor dysfunction due to the death of dopaminergic neurons in the substantia nigra pars compacta. Currently, treatment of PD has focused on increasing dopamine levels, using a dopamine precursor, levodopa (L-DOPA) or stimulation of dopaminergic receptors. Prolonged use of L-DOPA is associated with the occurrence of motor complications and dyskinesia, attributed to neurotoxic effects of this drug. The aim of this study was to investigate the effects of curcumin (CUR), a lipophilic polyphenol, to counteract L-DOPA induced toxicity. Zebrafish larvae were pre-treated with CUR (0.05 µM) or vehicle dimethyl sulfoxide (DMSO) for 24 hr and subsequently exposed to L-DOPA (1 mM) or vehicle. Immediately and 24 hr after L-DOPA exposure, spontaneous swimming and dark/light behavioral tests were performed. In addition, levels of reactive oxygen species (ROS) and lipid peroxidation products were determined at the end of treatment. CUR significantly improved the motor impairment induced by 24 hr L-DOPA treatment, and reduced levels of ROS and lipoperoxidation products in zebrafish larvae. In conclusion, our results suggest that CUR acts as a neuroprotector against toxicity initiated by L-DOPA. Evidence suggests the observed effects of CUR are associated with its antioxidant properties.

Bibliometric analysis of global research trends in adeno-associated virus vector for gene therapy (1991-2022)

Background

Gene therapy involves introducing and editing foreign genes in the body to treat and prevent genetic diseases. Adeno-associated virus (AAV) vector has become a widely used tool in gene therapy due to its high safety and transfection efficiency.

Methods

This study employs bibliometric analysis to explore the foundation and current state of AAV vector application in gene therapy research. A total of 6,069 publications from 1991 to 2022 were analyzed, retrieved from the Science Citation Index Expanded (SCI-E) within the Web of Science Core Collection (WoSCC) of Clarivate Analytics. Institutions, authors, journals, references, and keywords were analyzed and visualized by using VOSviewer and CiteSpace. The R language and Microsoft Excel 365 were used for statistical analyses.

Results

The global literature on AAV vector and gene therapy exhibited consistent growth, with the United States leading in productivity, contributing 3,868 papers and obtaining the highest H-index. Noteworthy authors like Wilson JM, Samulski RJ, Hauswirth WW, and Mingozzi F were among the top 10 most productive and co-cited authors. The journal "Human Gene Therapy" published the most papers (n = 485) on AAV vector and gene therapy. Current research focuses on "gene editing," "gene structure," "CRISPR," and "AAV gene therapy for specific hereditary diseases."

Conclusion

The application of AAV vector in gene therapy has shown continuous growth, fostering international cooperation among countries and institutions. The intersection of gene editing, gene structure, CRISPR, and AAV gene therapy for specific hereditary diseases and AAV vector represents a prominent and prioritized focus in contemporary gene therapy research. This study provides valuable insights into the trends and characteristics of AAV gene therapy research, facilitating further advancements in the field.

Unveiling the role of cerebellar alterations in the autonomic nervous system: a systematic review of autonomic dysfunction in spinocerebellar ataxias

BACKGROUND

Autonomic dysfunctions are prevalent in several cerebellar disorders, but they have not been systematically investigated in spinocerebellar ataxias (SCAs). Studies investigating autonomic deficits in SCAs are fragmented, with each one focusing on different autonomic dysfunctions and different SCA subtypes.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we conducted a systematic review of the literature to assess the presence of autonomic dysfunctions in various SCAs. PubMed served as the primary database, and the Rayyan web application was employed for study screening.

RESULTS

We identified 46 articles investigating at least one autonomic function in patients with SCA. The results were analyzed and categorized based on the genetic subtype of SCA, thereby characterizing the specific autonomic deficits associated with each subtype.

CONCLUSION

This review confirms the presence of autonomic dysfunctions in various genetic subtypes of SCA, underscoring the cerebellum's role in the autonomic nervous system (ANS). It also emphasizes the importance of investigating these functions in clinical practice.

Setting the clinical context to non-motor symptoms reflected by Park-pain, Park-sleep, and Park-autonomic subtypes of Parkinson's disease

Non-motor symptoms (NMS) of Parkinson's disease (PD) are well described in both clinical practice and the literature, enabling their management and enhancing our understanding of PD. NMS can dominate the clinical pictures and NMS subtypes have recently been proposed, initially based on clinical observations, and later confirmed in data driven analyses of large datasets and in biomarker-based studies. In this chapter, we provide an update on what is known about three common subtypes of NMS in PD. The pain (Park-pain), sleep dysfunction (Park-sleep), and autonomic dysfunction (Park-autonomic), providing an overview of their individual classification, clinical manifestation, pathophysiology, diagnosis, and potential treatments.

The Application of Deep Brain Stimulation for Parkinson's Disease on the Motor Pathway: A Bibliometric Analysis across 10 Years

BACKGROUND AND OBJECTIVE

Since its initial report by James Parkinson in 1817, Parkinson's disease (PD) has remained a central subject of research and clinical advancement. The disease is estimated to affect approximately 1% of adults aged 60 and above. Deep brain stimulation, emerging as an alternative therapy for end-stage cases, has offered a lifeline to numerous patients. This review aimed to analyze publications pertaining to the impact of deep brain stimulation on the motor pathway in patients with PD over the last decade.

METHODS

Data were obtained from the Web of Science Core Collection through the library of Huazhong University of Science and Technology (China). The search strategy encompassed the following keywords: "deep brain stimulation", "Parkinson's disease", "motor pathway", and "human", from January 1, 2012, to December 1, 2022. Additionally, this review visualized the findings using the Citespace software.

RESULTS

The results indicated that the United States, the United Kingdom, Germany, and China were the primary contributors to this research field. University College London, Capital Medical University, and Maastricht University were the top 3 research institutions in the research area. Tom Foltynie ranked first with 6 publications, and the journals of Brain and Brain Stimulation published the greatest number of relevant articles. The prevailing research focal points in this domain, as determined by keywords "burst analysis", "encompassed neuronal activity", "nucleus", "hyper direct pathway", etc. CONCLUSION: This study has provided a new perspective through bibliometric analysis of the deep brain stimulation therapy for treating patients with PD, which can shed light on future research to advance our comprehension of this particular field of study.

Autonomic dysregulation during sleep in Parkinsonian spectrum disorders - A proof of concept

INTRODUCTION

Autonomic dysfunction is common in α-synucleinopathies such as Lewy Body dementias (LBD), Parkinson's disease (PD), and isolated REM Sleep Behavior Disorder (iRBD). We analyzed pulse-rate changes during sleep to index autonomic nervous system (ANS) dysfunction in patients with α-synucleinopathies vs. non-synucleinopathy groups expected to have normal ANS function.

METHODS

Patients with LBD (n = 16), PD (PD, n = 14) or iRBD (n = 12) were compared to the non-synucleinopathy groups Alzheimers disease dementia (ADem, n = 26), mild cognitive impairment (MCI, n = 34) or controls (CG, n = 54). Sleep Profiler was used to derive a sleep autonomic activation index (AAI), i.e., ≥6 beat-per-minute increase/decrease, pulse rate coefficient of variation (PR-CV), and automated sleep staging with sleep-spindles and non-REM hypertonia (NRH). Analysis included statistical group comparisons and receiver operating characteristics curves to determine optimal classification of groups.

RESULTS

AAI and PR-CV were moderately correlated across all recordings (rs = 0.58, P < 0.0001), except in the LBD and PD groups. AAI but not PR-CV differentiated the LBD, PD and iRBD from non-Parkinsonian groups. AAI was decreased in LBD and PD patients compared to the CG (p < 0.003) and MCI (p < 0.03). AAI decreased based on age and its receiver operating characteristic area under the curve ranged from 0.63 to 0.75. AAI had a weak negative correlation to NRH (rs ≤ -0.26) but not sleep-spindles.

CONCLUSION

Synucleinopathy-related ANS dysfunction can reasonably discriminate prodromal and manifest PD/LBD diseased groups from non-synucleinopathies. Further studies incorporating AAI into a multivariate classifier of neurodegenerative disorders based on sleep characteristics acquired in the patient's home are planned.

Discovery of novel 2-(4-(benzyloxy)-5-(hydroxyl) phenyl) benzothiazole derivatives as multifunctional MAO-B inhibitors for the treatment of Parkinson's disease

To discover novel multifunctional agents for the treatment of Parkinson's disease, a series of 2-(4-(benzyloxy)-5-(hydroxyl) phenyl) benzothiazole derivatives was designed, synthesized and evaluated. The results revealed that representative compound 3h possessed potent and selective MAO-B inhibitory activity (IC₅₀ = 0.062 µM), and its inhibitory mode was competitive and reversible. Additionally, 3h also displayed excellent anti-oxidative effect (ORAC = 2.27 Trolox equivalent), significant metal chelating ability and appropriate BBB permeability. Moreover, 3h exhibited good neuroprotective effect and anti-neuroinflammtory ability. These results indicated that compound 3h was a promising candidate for further development against PD.

Association between Self-Reported Oral Health and Parkinson's Disease: Evidence from UK Biobank

OBJECTIVES

Oral health problem is prevalent in the elderly population which is also at high risk of Parkinson's disease (PD). However, the association between self-reported oral health and PD is still unclear. We aimed to explore the association between baseline self-reported oral health (mouth ulcers, painful gums, bleeding gums, loose teeth, toothache, dentures) and future incidence of PD.

METHODS AND PARTICIPANTS

Participants were enrolled in the UK Biobank from 2006 to 2010 and those without PD at baseline were included in the current study. We used Cox regression analysis to explore the question and adjusted for age, sex, body mass index, smoking, drinking, ethnicity, education, socioeconomic status, and average total household income before tax.

RESULTS

We included 421,180 participants with a mean age of 56.26 years old, and 46.5% of them were male. And 2,339 participants were diagnosed with PD in the follow-up. Mouth ulcers, loose teeth, dentures, toothache, and bleeding gums were not related to the risk of PD. Painful gums were related to a higher risk of PD (HR: 1.39, 95% CI: 1.12-1.72, p = 0.003), and similar results were reached after adjusting for gene risk (HR: 1.39, 95% CI: 1.12-1.73, p = 0.003), or source of diagnosis (HR: 1.39, 95% CI: 1.12-1.72, p = 0.002), and time of diagnosis (HR: 1.29, 95% CI: 1.03-1.63, p = 0.02).

CONCLUSIONS

Our study has demonstrated a substantial correlation between painful gums and elevated susceptibility to PD, underscoring the potential advantages of implementing oral health interventions for decreasing the risk of PD.

Non-pharmacological and drug treatment of autonomic dysfunction in multiple system atrophy: current status and future directions

Multiple system atrophy (MSA) is a sporadic, fatal, and rapidly progressive neurodegenerative disease of unknown etiology that is clinically characterized by autonomic failure, parkinsonism, cerebellar ataxia, and pyramidal signs in any combination. Early onset and extensive autonomic dysfunction, including cardiovascular dysfunction characterized by orthostatic hypotension (OH) and supine hypertension, urinary dysfunction characterized by overactive bladder and incomplete bladder emptying, sexual dysfunction characterized by sexual desire deficiency and erectile dysfunction, and gastrointestinal dysfunction characterized by delayed gastric emptying and constipation, are the main features of MSA. Autonomic dysfunction greatly reduces quality of life and increases mortality. Therefore, early diagnosis and intervention are urgently needed to benefit MSA patients. In this review, we aim to discuss the systematic treatment of autonomic dysfunction in MSA, and focus on the current methods, starting from non-pharmacological methods, such as patient education, psychotherapy, diet change, surgery, and neuromodulation, to various drug treatments targeting autonomic nerve and its projection fibers. In addition, we also draw attention to the interactions among various treatments, and introduce novel methods proposed in recent years, such as gene therapy, stem cell therapy, and neural prosthesis implantation. Furthermore, we elaborate on the specific targets and mechanisms of action of various drugs. We would like to call for large-scale research to determine the efficacy of these methods in the future. Finally, we point out that studies on the pathogenesis of MSA and pathophysiological mechanisms of various autonomic dysfunction would also contribute to the development of new promising treatments and concepts.

Rapamycin reverses ferroptosis by increasing autophagy in MPTP/MPP+-induced models of Parkinson's disease

Parkinson's disease is a neurodegenerative disorder, and ferroptosis plays a significant role in the pathological mechanism underlying Parkinson's disease. Rapamycin, an autophagy inducer, has been shown to have neuroprotective effects in Parkinson's disease. However, the link between rapamycin and ferroptosis in Parkinson's disease is not entirely clear. In this study, rapamycin was administered to a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease mouse model and a 1-methyl-4-phenylpyridinium-induced Parkinson's disease PC12 cell model. The results showed that rapamycin improved the behavioral symptoms of Parkinson's disease model mice, reduced the loss of dopamine neurons in the substantia nigra pars compacta, and reduced the expression of ferroptosis-related indicators (glutathione peroxidase 4, recombinant solute carrier family 7, member 11, glutathione, malondialdehyde, and reactive oxygen species). In the Parkinson's disease cell model, rapamycin improved cell viability and reduced ferroptosis. The neuroprotective effect of rapamycin was attenuated by a ferroptosis inducer (methyl (1S,3R)-2-(2-chloroacetyl)-1-(4-methoxycarbonylphenyl)-1,3,4,9-tetrahyyridoindole-3-carboxylate) and an autophagy inhibitor (3-methyladenine). Inhibiting ferroptosis by activating autophagy may be an important mechanism by which rapamycin exerts its neuroprotective effects. Therefore, the regulation of ferroptosis and autophagy may provide a therapeutic target for drug treatments in Parkinson's disease.

Association between the risk and severity of Parkinson's disease and plasma homocysteine, vitamin B12 and folate levels: a systematic review and meta-analysis

Background

Parkinson's disease (PD) is recognized as the second most prevalent progressive neurodegenerative disease among the elderly. However, the relationship between PD and plasma homocysteine (Hcy), vitamin B12, and folate has yielded inconsistent results in previous studies. Hence, in order to address this ambiguity, we conducted a meta-analysis to summarize the existing evidence.

Methods

Suitable studies published prior to May 2023 were identified by searching PubMed, EMBASE, Medline, Ovid, and Web of Science. The methodological quality of eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Meta-analysis and publication bias were then performed using R version 4.3.1.

Results

The results of our meta-analysis, consisting of case-control and cross-sectional studies, showed that PD patients had lower folate and vitamin B12 levels (SMD [95%CI]: -0.30[-0.39, -0.22], p < 0.001 for Vitamin B12; SMD [95%CI]: -0.20 [-0.28, -0.13], p < 0.001 for folate), but a significant higher Hcy level (SMD [95%CI]: 0.86 [0.59, 1.14], p < 0.001) than healthy people. Meanwhile, PD was significantly related to hyperhomocysteinemia (SMD [95%]: 2.02 [1.26, 2.78], p < 0.001) rather than plasma Hcy below 15 μmol/L (SMD [95%]: -0.31 [-0.62, 0.00], p = 0.05). Subgroup analysis revealed associations between the Hcy level of PD patients and region (p = 0.03), age (p = 0.03), levodopa therapy (p = 0.03), Hoehn and Yahr stage (p < 0.001), and cognitive impairment (p < 0.001). However, gender (p = 0.38) and sample size (p = 0.49) were not associated.

Conclusion

Hcy, vitamin B12, and folic acid potentially predict the onset and development of PD. Additionally, multiple factors were linked to Hcy levels in PD patients. Further studies are needed to comprehend their roles in PD.

Parkinson's disease patients combined with constipation tend to have higher serum expression of microRNA 29c, prominent neuropsychiatric disorders, possible RBD conversion, and a substandard quality of life

INTRODUCTION

The symptom of constipation has been confirmed as an early diagnose criteria for Parkinson's disease (PD). Furthermore, evidences suggest that pathogenesis of PD initiates in gut, rather than brain. If so, identifying biomarkers for constipation in PD might have potentials to assist early diagnosis and initial treatment.

METHOD

We first identified that microRNA 29c (miR-29c) was dysregulated both in PD and constipation patients through bioinformatics analysis. Then, serological analysis of the expression of miR-29c in 67 PD patients with constipation (PD-C), 51 PD patients without constipation (PD-NC), and 50 healthy controls (HC) was carried out by qPCR. Demographic and clinical features were also compared. Patients in PD-C group were further classified into two groups: those with prodromal stage constipation (PD-C-Pro) (n = 36) and those with clinical stage constipation (PD-C-Clinic) (n = 31), to explore their different characteristics.

RESULTS

The levels of miR-29c in PD-C group were higher than that in PD-NC group, both higher than HC group. PD-C-Pro group's miR-29c levels were statistically higher compared with PD-C-Clinic group's. What is more, PD-C group had higher scores of MDS-UPDRS-I, NMSS, NMSS3, NMSS4, NMSS6, NMSS9, SCOPA-AUT, HAMD, HAMA, RBDSQ, CSS, and PACQOL compared with PD-NC party. Relative to the PD-C-Clinic, patients in PD-C-Pro group had higher MDS-UPDRS-I, NMSS, NMSS3, HAMD, and HAMA scores, and were more likely to have RBD.

CONCLUSION

Our results indicated that miR-29c seems to be an underlying cause for developing constipation in patients with PD and PD-C identifies a group of patients with more severe non-motor impairment, prominent neuropsychiatric disorders, and possible RBD conversion as well as a substandard quality of life. We further confirmed that there is a close relationship between symptoms representing the same pathological origin, especially constipation and RBD.

A Strainer-Based Platform for the Collection and Immunolabeling of Mouse Intestinal Organoids

Intestinal organoids have emerged as powerful model systems for studying the complex structure and function of the intestine. However, there is a lack of widely applicable methods for the collection, labeling, and imaging of intestinal organoids. In this study, we developed a novel method for loading and labeling intestinal organoids, a method that efficiently collects the organoids and facilitates imaging of their three-dimensional (3D) structure. Based on this strainer platform, mouse intestinal organoids were adequately collected and immobilized, facilitating the immunolabeling workflow to target proteins of the organoids. After evaluation, the strainer size of 40 μm was considered to be more conducive to the collection and labeling of mouse intestinal organoids. More extensive research on organoids of multiple types and species origins will contribute to broadening the applicability of the methodology. Overall, our study proposes an innovative workflow for loading and analyzing intestinal organoids. The combination of a strainer-based collection method, fluorescent labeling, and 3D reconstruction provides valuable insights into the organization and complexity of these tissue models, thereby offering new avenues for investigating intestinal development, disease modeling, and drug discovery.

Increased Free Water in the Putamen in Idiopathic REM Sleep Behavior Disorder

BACKGROUND

It has been suggested that the loss of nigrostriatal dopaminergic axon terminals occurs before the loss of dopaminergic neurons in the substantia nigra (SN) in Parkinson's disease (PD). This study aimed to use free-water imaging to evaluate microstructural changes in the dorsoposterior putamen (DPP) of idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) patients, which is considered a prodromal stage of synucleinopathies.

METHODS

Free water values in the DPP, dorsoanterior putamen (DAP), and posterior SN were compared between the healthy controls (n = 48), iRBD (n = 43) and PD (n = 47) patients. In iRBD patients, the relationships between baseline and longitudinal free water values and clinical manifestations or dopamine transporter (DAT) striatal binding ratio (SBR) were analyzed.

RESULTS

Free water values were significantly higher in the DPP and posterior substantia nigra (pSN), but not in the DAP, in the iRBD and PD groups than in controls. In iRBD patients, free water values in the DPP were progressively increased and correlated with the progression of clinical manifestations and the striatal DAT SBR. Baseline free water in the DPP was negatively correlated with striatal DAT SBR and hyposmia and positively correlated with motor deficits.

CONCLUSIONS

This study demonstrates that free water values in the DPP are increased cross-sectionally and longitudinally and associated with clinical manifestations and the function of the dopaminergic system in the prodromal stage of synucleinopathies. Our findings indicate that free-water imaging of the DPP has the potential to be a valid marker of early diagnosis and progression of synucleinopathies. © 2023 International Parkinson and Movement Disorder Society.

Clinical and Non-Clinical Cardiovascular Disease Associated Pathologies in Parkinson's Disease

Despite considerable breakthroughs in Parkinson's disease (PD) research, understanding of non-motor symptoms (NMS) in PD remains limited. The lack of basic level models that can properly recapitulate PD NMS either in vivo or in vitro complicates matters. Even so, recent research advances have identified cardiovascular NMS as being underestimated in PD. Considering that a cardiovascular phenotype reflects sympathetic autonomic dysregulation, cardiovascular symptoms of PD can play a pivotal role in understanding the pathogenesis of PD. In this study, we have reviewed clinical and non-clinical published papers with four key parameters: cardiovascular disease risks, electrocardiograms (ECG), neurocardiac lesions in PD, and fundamental electrophysiological studies that can be linked to the heart. We have highlighted the points and limitations that the reviewed articles have in common. ECG and pathological reports suggested that PD patients may undergo alterations in neurocardiac regulation. The pathological evidence also suggested that the hearts of PD patients were involved in alpha-synucleinopathy. Finally, there is to date little research available that addresses the electrophysiology of in vitro Parkinson's disease models. For future reference, research that can integrate cardiac electrophysiology and pathological alterations is required.

Multicohort cross-sectional study of cognitive and behavioural digital biomarkers in neurodegeneration: the Living Lab Study protocol

INTRODUCTION AND AIMS

Digital biomarkers can provide a cost-effective, objective and robust measure for neurological disease progression, changes in care needs and the effect of interventions. Motor function, physiology and behaviour can provide informative measures of neurological conditions and neurodegenerative decline. New digital technologies present an opportunity to provide remote, high-frequency monitoring of patients from within their homes. The purpose of the living lab study is to develop novel digital biomarkers of functional impairment in those living with neurodegenerative disease (NDD) and neurological conditions.

METHODS AND ANALYSIS

The Living Lab study is a cross-sectional observational study of cognition and behaviour in people living with NDDs and other, non-degenerative neurological conditions. Patients (n≥25 for each patient group) with dementia, Parkinson's disease, amyotrophic lateral sclerosis, mild cognitive impairment, traumatic brain injury and stroke along with controls (n≥60) will be pragmatically recruited. Patients will carry out activities of daily living and functional assessments within the Living Lab. The Living Lab is an apartment-laboratory containing a functional kitchen, bathroom, bed and living area to provide a controlled environment to develop novel digital biomarkers. The Living Lab provides an important intermediary stage between the conventional laboratory and the home. Multiple passive environmental sensors, internet-enabled medical devices, wearables and electroencephalography (EEG) will be used to characterise functional impairments of NDDs and non-NDD conditions. We will also relate these digital technology measures to clinical and cognitive outcomes.

ETHICS AND DISSEMINATION

Ethical approvals have been granted by the Imperial College Research Ethics Committee (reference number: 21IC6992). Results from the study will be disseminated at conferences and within peer-reviewed journals.

Casein Reactivates Dopaminergic Nerve Injury and Intestinal Inflammation with Disturbing Intestinal Microflora and Fecal Metabolites in a Convalescent Parkinson's Disease Mouse Model

Parkinson's disease (PD) is the fastest-growing neurodegenerative disease, with pathogenic causes elusive and short of effective treatment options. Investigations have found that dairy products positively correlate with the onset of PD, but the mechanisms remain unexplored. As casein is an antigenic component in dairy products, this study assessed if casein could exacerbate PD-related symptoms by stimulating intestinal inflammation and unbalanced intestinal flora and be a risk factor for PD. Using a convalescent PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), the results showed casein reduced motor coordination, caused gastrointestinal dysfunction, reduced dopamine content, and induced intestinal inflammation. Meanwhile, casein disturbed gut microbiota homeostasis by increasing the Firmicutes/Bacteroidetes ratio, decreasing α-diversity, and caused abnormal alterations in fecal metabolites. However, these adverse effects of casein attenuated much when it had hydrolyzed by acid or when antibiotics inhibited the intestinal microbiota of the mice. Therefore, our results suggested that casein could reactivate dopaminergic nerve injury and intestinal inflammation and exacerbate intestinal flora disorder and its metabolites in convalescent PD mice. These damaging effects might be related to disordered protein digestion and gut microbiota in these mice. These findings will provide new insights into the impact of milk/dairy products on PD progression and supply information on dietary options for PD patients.

Urolithin A in Health and Diseases: Prospects for Parkinson's Disease Management

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder characterized by a complex pathophysiology and a range of symptoms. The prevalence increases with age, putting the ageing population at risk. Disease management includes the improvement of symptoms, the comfort of the patient's life, and palliative care. As there is currently no cure, growing evidence points towards the beneficial role of polyphenols on neurodegeneration. Numerous studies indicate the health benefits of the family of urolithins, especially urolithin A (UA). UA is a bacterial metabolite produced by dietary ellagitannins and ellagic acid. An expanding body of literature explores the involvement of the compound in mitochondrial health, and its anti-inflammatory, anti-oxidant, and anti-apoptotic properties. The review organizes the existing knowledge on the role of UA in health and diseases, emphasizing neurodegenerative diseases, especially PD. We gathered data on the potential neuroprotective effect in in vivo and in vitro models. We discussed the possible mechanisms of action of the compound and related health benefits to give a broader perspective of potential applications of UA in neuroprotective strategies. Moreover, we projected the future directions of applying UA in PD management.