Cardiovascular effects of levodopa in Parkinson's disease

Peripheral autonomic failure is associated with more severe postprandial hypotension compared to central autonomic failure

PURPOSE

Postprandial hypotension (PPH) defined as a decrease in systolic blood pressure of more than 20 mmHg within 2 h post meal is prevalent in patients with autonomic failure and is associated with negative cardiovascular outcomes. Previous studies reported peripheral autonomic failure with less residual sympathetic tone in Parkinson disease (PD). Therefore, we hypothesized that PPH is more severe in PD than in multiple system atrophy (MSA) with central autonomic failure.

METHODS

Thirteen patients with PD and 13 patients with MSA were enrolled. Autonomic function testing and neurohormonal measurements were performed to assess autonomic failure and residual sympathetic activity. Subjects were fed a standard breakfast. Systolic and diastolic blood pressure and heart rate were monitored every 5 min from 30 min before to 120 min post meal. Postprandial hemodynamic changes were summarized using area under the curve (AUC). Differences between the groups were assessed with two-sample independent t test and linear regression.

RESULTS

Patients with PD (69% male, 72 ± 9 years) had a significantly lower post-meal diastolic blood pressure (P = 0.003) and heart rate AUC (P = 0.007) than patients with MSA (62% male, 62 ± 8 years). After adjusting for age and supine systolic blood pressure, PD as diagnosis still had significant estimate effect for diastolic blood pressure AUC (P = 0.019). No significant difference was found in the mean systolic blood pressure AUC, but at 30 min post meal, systolic blood pressure decrease was significantly lower in PD (P = 0.016).

CONCLUSION

The PD group with peripheral autonomic failure exhibits more severe PPH than the MSA group. This highlights the need for tailored management for PPH in PD.

Wearable multimodal sensing for quantifying the cardiovascular autonomic effects of levodopa in parkinsonism

Levodopa is the most common therapy to reduce motor symptoms of parkinsonism. However, levodopa has potential to exacerbate cardiovascular autonomic (CVA) dysfunction that may co-occur in patients. Heart rate variability (HRV) is the most common method for assessing CVA function, but broader monitoring of CVA function and levodopa effects is typically limited to clinical settings and symptom reporting, which fail to capture its holistic nature. In this study, we evaluated the feasibility of a multimodal wearable chest patch for monitoring changes in CVA function during clinical and 24-h ambulatory (at home) conditions in 14 patients: 11 with Parkinson's disease (PD) and 3 with multiple system atrophy (MSA). In-clinic data were analyzed to examine the effects of orally administered levodopa on CVA function using a pre (OFF) and 60-min (ON) post-exposure protocol. Wearable-derived physiological markers related to the electrical and mechanical activity of the heart alongside vascular function were extracted. Pre-ejection period (PEP) and ratio of PEP to left ventricular ejection time index (LVETi) increased significantly (p < 0.05) following levodopa, indicating a decrease in cardiac contractility. We further explored dose-response relationships and how CVA responses differed between participants with orthostatic hypotension (OH) from those without OH. Heart rate variability, specifically root-mean-square-of-successive-differences (RMSSD), following levodopa decreased significantly more in participants with OH (n = 7) compared to those without (no-OH, n = 7). The results suggest that the wearable patch's measures are sensitive to CVA dynamics and provide exploratory insights into levodopa's potential role in inducing a negative inotropic effect and exacerbating CVA dysfunction. This work encourages further evaluation of these wearable-derived physiomarkers for quantifying CVA and informing individualized care of individuals with parkinsonism.

Interoception in Parkinson's disease: A narrative review and framework for translational research

Parkinson's disease (PD) is the second most common, and the fastest growing, neurodegenerative disease worldwide. Non-motor manifestations, particularly autonomic nervous system dysfunction, are common throughout the disease course, in some cases preceding motor symptom onset by years, and are often more disabling and harder to treat than motor symptoms and contribute significantly to disability. An understudied consequence of autonomic and visceral dysfunction in PD is interoception, the neural processing of internal organ system signals. Interoceptive processes form a foundational body-brain interface, mediating basic homeostatic reflexes and complex physiologic and behavioral adaptive responses to internal perturbations. Emerging evidence exists that interoception is impaired in some individuals with PD, potentially explaining why those who have objective evidence of autonomic dysfunction do not always report typical symptoms. Failure to recognize these impairments may lead to missed opportunities for early intervention, particularly in addressing 'silent' autonomic disturbances (e.g., orthostatic hypotension leading to sudden falls, dysphagia leading to aspiration pneumonia). In this narrative review, we synthesize current findings on the neuroanatomical networks underlying interoception, examine clinical manifestations of interoceptive dysfunction across multiple organ systems in PD, and identify key gaps in knowledge. We propose a translational research framework to enhance early detection, symptom management, and intervention strategies for PD. This framework integrates cognitive, mood, and autonomic dysfunctions with clinical factors (disease stage, duration, motor subtype, levodopa status) to understand interoceptive dysfunction within a translational model. This approach highlights novel opportunities for personalized care and improved therapeutic interventions in PD.

Association Between Levodopa with Inotrope Prescription and Mechanical Ventilation Dependence in People with Parkinson's Disease upon Septic Shock

Background/Objectives: People with Parkinson's disease (PwP) face high risks of bacterial infections and septic shock, often requiring inotrope treatment and mechanical ventilation. The impact of levodopa on these critical care interventions remains unclear. Methods: This retrospective cohort study analyzed data from the Taipei Medical University Clinical Research Database to explore the relationship between levodopa prescription, inotrope treatment duration, and mechanical ventilation dependence in PwP who experienced septic shock. PwP aged 45 years and older who required intensive care for septic shock were categorized into levodopa and non-levodopa groups. Results: Outcomes included inotrope treatment duration, mechanical ventilation dependence, and 3-month mortality. Among 243 PwP (116 without levodopa, 127 with levodopa), no significant difference was observed in the duration of mechanical ventilation dependence. However, levodopa prescription was associated with a significantly extended inotrope treatment duration (estimate: 3.43 days, p = 0.027). Additionally, a nonsignificant trend was identified between levodopa prescription and reduced 3-month mortality (adjusted hazard ratio = 0.67, p = 0.068). Conclusions: These findings highlight the complex interplay between Parkinson's disease management and critical care interventions during septic shock. While levodopa may prolong inotrope use, its potential to influence survival outcomes warrants further investigation.

Blood pressure targets, medication considerations and special concerns in elderly hypertension III: Focus on stroke and neurodegenerative disorders

Controlling hypertension has become an important issue in the elderly population in whom neurological comorbidities are highly prevalent. Most of the large-scale trials focusing on hypertension management in older populations have excluded patients with comorbid neurological disorders. However, this population requires special considerations, as the benefits of antihypertensive agents are mostly uncertain and there is a higher risk of adverse events. In this review article, we discuss current evidence regarding the management of elderly patients with hypertension and common neurological disorders, including stroke and neurodegenerative diseases. In elderly patient with a history of stroke, the blood pressure management strategy is generally similar to that for young patients, however the benefits of stroke prevention from blood pressure control are less significant. For patients with neurodegenerative disorders such as cognitive dysfunction and Parkinson's disease, achieving adequate blood pressure control may be beneficial in reducing cardiovascular risks, although the higher risk of adverse events from antihypertensive treatment may offset some of these benefits. Special considerations for factors such as orthostatic hypotension, risk of falls, polypharmacy, and significant drug-drug interactions are required but frequently neglected in clinical practice. More efforts are warranted to determine the optimal treatment strategy for elderly populations with neurological disorders.

Trends in Mortality Due to Cardiovascular Diseases Among Patients With Parkinson's Disease in the United States: A Retrospective Analysis

BACKGROUND

Parkinson disease (PD) and cardiovascular diseases (CVD) present significant health burdens, particularly among older adults. Patients with PD have an elevated risk of CVD-related mortality. Analyzing mortality trends in this population may help guide focused interventions.

METHODS

Mortality data were extracted from the CDC WONDER database, using ICD-10 code G20 for PD and I00-I99 for CVD. Age-adjusted mortality rates (AAMR) per 100,000 were calculated and trends were examined across variables including gender, year, race, and urbanization, place of death, region, and state. Annual percentage change (APC) with 95% confidence intervals (CI) was computed using Joinpoint regression.

RESULTS

A total of 138 151 CVD-related deaths were reported among individuals with PD. The AAMR decreased from 23.5 in 1999 to 12.7 in 2020, with a notable decline between 1999 and 2014 (APC: -5.13; 95% CI, -5.44 to -4.86), followed by a modest increase from 2014 to 2020 (APC: 1.37; 95% CI, 0.16-3.05). Males exhibited higher AAMRs compared to females (Male AAMR: 22.6 vs. Female AAMR: 10.4). Non-Hispanic (NH) Whites had the highest AAMR (16.1), followed by Hispanics (11.2), NH Asians (10.2), and NH Blacks (9.7). Nonmetropolitan areas showed a higher AAMR (16.3) compared to metropolitan areas (14.9). State-level analysis indicated Nebraska with the highest AAMR (21.4), while Georgia recorded the lowest (9.9).

CONCLUSIONS

CVD-related mortality in PD patients has declined overall, though rates rose slightly from 2014 to 2020. Gender, racial, and geographic disparities highlight the need for targeted strategies to reduce cardiovascular risks in this population.

[Correlation of motor symptoms and cardiovascular dysfunction in Parkinson's disease]

OBJECTIVE

Assessment of cardiovascular (CV) dysfunction, its association with motor symptoms of Parkinson's disease (PD) and dopaminergic therapy.

MATERIAL AND METHODS

The study included 252 patients with Hoehn and Yahr stage I-III PD. All patients were assessed using a survey of symptoms of orthostatic intolerance (OI), an orthostatic test, UPDRS II-IV, a Sch&En daily activity score, and a Mini-Mental State Examination (MMSE). A heart rate variability (HRV) test was performed on 31 patients and 10 control subjects of comparable age.

RESULTS

OI symptoms were detected in 35.3% of patients, orthostatic hypotension in 5.8%, and lying hypertension in 34%. The HRV indices (SDNN, TP, VLF, and LF) were decreased in all patients versus the controls (p<0.0001); no normal increase in sympathetic effects occurred with the orthostatic test. The PD stage was associated with OI symptoms (p=0.003), a decrease in the total HRV power (rS=-0.357; p=0.049), an increase in lying hypertension and heart rate, and a decrease in changes in heart rate during the orthostatic test. Patients with OI symptoms had longer PD history and worse Sch&En and UPDRS scores (hypokinesia, posture, resistance, dyskinesia scores). Significant negative correlations of HRV were identified with the same motor indices: UPDRS II and III, impaired gait, posture, stiffness, and rigidity. Resting tremor or action tremor had no association with HRV and OI. The use of dopaminergic drugs (levodopa, amantadines, dopamine receptor agonists) was associated with lower systemic blood pressure and OI symptoms but did not aggravate orthostatic responses and HRV.

CONCLUSION

Obtained data indicate the presence in patients with the initial stages of PD of autonomic CV dysfunction, closely related to the motor (especially walking and postural balance) symptoms of PD by a single neurodegenerative process covering both central and peripheral structures of the autonomic nervous system.

Optical coherence tomography angiography of the retina and choroid in systemic diseases

Optical coherence tomography angiography (OCTA) has transformed ocular vascular imaging, revealing microvascular changes linked to various systemic diseases. This review explores its applications in diabetes, hypertension, cardiovascular diseases, and neurodegenerative diseases. While OCTA provides a valuable window into the body's microvasculature, interpreting the findings can be complex. Additionally, challenges exist due to the relative non-specificity of its findings where changes observed in OCTA might not be unique to a specific disease, variations between OCTA machines, the lack of a standardized normative database for comparison, and potential image artifacts. Despite these limitations, OCTA holds immense potential for the future. The review highlights promising advancements like quantitative analysis of OCTA images, integration of artificial intelligence for faster and more accurate interpretation, and multi-modal imaging combining OCTA with other techniques for a more comprehensive characterization of the ocular vasculature. Furthermore, OCTA's potential future role in personalized medicine, enabling tailored treatment plans based on individual OCTA findings, community screening programs for early disease detection, and longitudinal studies tracking disease progression over time is also discussed. In conclusion, OCTA presents a significant opportunity to improve our understanding and management of systemic diseases. Addressing current limitations and pursuing these exciting future directions can solidify OCTA as an indispensable tool for diagnosis, monitoring disease progression, and potentially guiding treatment decisions across various systemic health conditions.

Cardiovascular dysautonomia and cognitive impairment in Parkinson's disease (Review)

Cognitive impairment is a prevalent non-motor symptom of Parkinson's disease (PD), which can result in significant disability and distress for patients and caregivers. There is a marked variation in the timing, characteristics and rate at which cognitive decline occurs in patients with PD. This decline can vary from normal cognition to mild cognitive impairment and dementia. Cognitive impairment is associated with several pathophysiological mechanisms, including the accumulation of β-amyloid and tau in the brain, oxidative stress and neuroinflammation. Cardiovascular autonomic dysfunctions are commonly observed in patients with PD. These dysfunctions play a role in the progression of cognitive impairment, the incidents of falls and even in mortality. The majority of symptoms of dysautonomia arise from changes in the peripheral autonomic nervous system, including both the sympathetic and parasympathetic nervous systems. Cardiovascular changes, including orthostatic hypotension, supine hypertension and abnormal nocturnal blood pressure (BP), can occur in both the early and advanced stages of PD. These changes tend to increase as the disease advances. The present review aimed to describe the cognitive changes in the setting of cardiovascular dysautonomia and to discuss strategies through which these changes can be modified and managed. It is a multifactorial process usually involving decreased blood flow to the brain, resulting in the development of cerebral ischemic lesions, an increased presence of abnormal white matter signals in the brain, and a potential influence on the process of neurodegeneration in PD. Another possible explanation is this association being independent observations of PD progression. Patients with clinical symptoms of dysautonomia should undergo 24-h ambulatory BP monitoring, as they are frequently subtle and underdiagnosed.

Intrarater Reliability and Agreement of Blood Pressure, Arterial Stiffness, and Heart Rate Variability Assessments in Patients With Parkinson's Disease

To assess the intrarater reliability and agreement of blood pressure (BP), arterial stiffness, and heart rate variability (HRV) assessments in patients with Parkinson`s disease (PD). Twenty patients with PD visited the laboratory three times, during which brachial and central BP (auscultatory and applanation tonometry, respectively), arterial stiffness (carotid-femoral pulse wave velocity and augmentation index), and HRV assessments were performed at rest. Brachial and central systolic BP presented greater values on visit 1 when compared to visits 2 and 3 (122±13 vs. 116±16 vs. 120±15, p=0.029). There were no significant differences (p>0.05) among the experimental visits for other parameters. Brachial and central BP showed an intraclass correlation coefficient (ICC) above 0.842 and a standard error of measurement (SEM) lower than 5.0%. Bland-Altman plots indicated low agreement between visits 1 and 2 and good agreement between visits 2 and 3. Arterial stiffness indices exhibited ICC values between 0.781 and 0.886, and SEM ranged from 7.3% to 25.2%. Bland-Altman plots indicated moderate to good agreement among visits for arterial stiffness parameters. HRV indices presented ICC values ranging from 0.558 to 0.854 and SEM values ranging from 5.1% to 76.0%. Bland-Altman plots indicated moderate agreement among visits for HRV parameters. In PD patients, brachial and central BP present low intrarater reliability and agreement between visits 1 and 2 and good intrarater reliability and agreement between visits 2 and 3. In general, arterial stiffness and HRV assessments present acceptable intrarater reliability and agreement among visits, except for cardiac sympathovagal balance.

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.

Effect of levodopa on postural blood pressure changes in Parkinson disease: a randomized crossover study

PURPOSE

We investigated the effect of levodopa on postural blood pressure changes in individuals with Parkinson disease (PD) with (PD+OH) and without neurogenic OH (PD-OH).

METHODS

We performed a prospective randomized crossover study with autonomic testing performed ON and OFF levodopa. The primary outcome was the change in systolic blood pressure (SBP) from supine to 70° tilt at 3 min (ΔSBP-3'). Secondary outcomes included indices of baroreflex function and blood pressure and heart rate during tilt.

RESULTS

We enrolled 40 individuals with PD (21 PD+OH, 19 PD-OH), mean age (SD) 73.2 years (7.9), 13 women (32.5%)). There was no difference in age, sex, disease duration, and severity between PD+OH and PD-OH. Mean difference in ΔSBP-3' ON versus OFF levodopa in the whole study population was - 3.20 mmHg [- 7.36 to 0.96] (p = 0.14). Mean difference in ΔSBP-3' was - 2.14 mmHg [- 7.55 to 3.28] (p = 0.45) in PD+OH and - 5.14 mmHg [- 11.63 to 1.35] (p = 0.14) in PD-OH. Mean difference in ΔSBP ON versus OFF levodopa was greater at 7 and 10 min (- 7.52 mmHg [- 11.89 to - 3.15], p = 0.002, and - 7.82 mmHg [- 14.02 to - 1.67], p = 0.02 respectively). Levodopa was associated with lower absolute values of blood pressure in both PD+OH and PD-OH and cardiovascular noradrenergic baroreflex impairment.

CONCLUSION

Levodopa decreases blood pressure in both PD with and without autonomic failure, but it does not cause a greater fall in blood pressure from supine to standing at 3 min. Levodopa-induced baroreflex sympathetic noradrenergic impairment may contribute to lower blood pressure. Lower standing blood pressure with levodopa may increase the risks of fall and syncope.

Levodopa-induced orthostatic hypotension in parkinsonism: A red flag of autonomic failure

BACKGROUND AND PURPOSE

Levodopa (LD) is the main treatment for parkinsonism, but its use may be limited by a potential hypotensive effect.

METHODS

We evaluated the cardiovascular effect of LD performing head-up tilt test (HUTT) before and 60 min after 100/25 mg LD/dopa-decarboxylase inhibitor (pre-LD vs. post-LD HUTT) in 164 patients with parkinsonism on chronic LD treatment. Features predictive of LD-induced orthostatic hypotension (OH) were assessed by logistic regression analysis.

RESULTS

Basal supine blood pressure (BP) and heart rate (HR) decreased after LD. During post-LD HUTT, BP drop and HR increase were significantly greater than at pre-LD HUTT. Thirty-eight percent of patients had OH at post-LD HUTT compared to 22% of patients presenting OH at pre-LD HUTT (p < 0.001). Risk factors for LD-induced/worsened OH were pre-LD OH (odds ratio [OR] = 36, 95% confidence interval [CI] = 10-131), absence of overshoot at Valsalva maneuver (OR = 9, 95% CI = 4-20), and pathological Valsalva ratio (OR = 6, 95% CI = 2-15).

CONCLUSIONS

LD administration caused/worsened hypotension in both supine and orthostatic conditions. Patients with cardiovascular autonomic failure had a higher risk of developing LD-induced OH. In clinical practice, LD-induced OH could represent a red flag for cardiovascular autonomic failure.

Acute effect of levodopa on orthostatic hypotension and its association with motor responsiveness in Parkinson's disease: Results of acute levodopa challenge test

OBJECTIVE

Levodopa administration can induce or worsen orthostatic hypotension (OH) in patients with Parkinson's disease (PD). Understanding of acute OH post levodopa (AOHPL) is important for rational drug use in PD patients. Primary objective of this study was to investigate the incidence of AOHPL in PD patients. The secondary objectives were a) hemodynamic character of AOHPL; b) risk factors of AOHPL; c) relationship between motor responsiveness and blood pressure (BP) change.

METHODS

490 PD inpatients underwent acute levodopa challenge test (LCT). Supine-to-standing test (STS) was done 4 times during LCT, including before levodopa and every hour post levodopa intake within 3 h. Patients were classified into two groups, AOHPL and non-AOHPL. A comprehensive set of clinical features scales was assessed, including both motor (e.g., motor response, wearing-off) and nonmotor symptoms (e.g., autonomic dysfunction, neuropsychology).

RESULTS

33.1% PD patients had OH before drug, 50.8% the same subjects had AOHPL during levodopa effectiveness. PD patients who had better response to levodopa likely to have lower standing mean artery pressure (MAP) and severer systolic BP drop after levodopa intake. BP increased when the motor performance worsened and vice versa. Beneficial response was a risk factors of AOHPL (OR = 1.624, P = 0.017).

CONCLUSIONS

AOHPL was very common in PD patients. We suggested that PD patients with risk factors should monitor hemodynamic change during LCT to avoid AOHPL following the introduction or increase of oral levodopa. The fluctuations of BP were complicated and multifactorial, likely caused by the process of PD and levodopa both.

Effects of different levodopa doses on blood pressure in older patients with early and middle stages of Parkinson's disease

Objective

Levodopa is the first-line treatment for patients with Parkinson's disease (PD). However, only a few studies have focused on the tolerance of this drug in older patients with PD in the early and middle stages. Therefore, this study aimed to explore the effects of different levodopa doses on blood pressure (BP) in this subpopulation.

Methods

This cohort analysis enrolled 83 patients. The levodopa challenge test was used to evaluate drug responsiveness. After at least 12 h following anti-PD drug discontinuation, patients' BPs were measured in a lying position, after 1 min standing, and after 3 min standing, in "off state" and best "on state."

Results

BP in the 250 mg and 375 mg levodopa/benserazide groups decreased significantly in the lying and standing positions. The 3-min standing-position systolic BP was significantly influenced by the dose of levodopa/benserazide. However, no statistical change was observed in the 125 mg group. The postural-mediated systolic BP disparity was significant at 3 min in the upright position. Nineteen (incidence, 22.9%) and Twenty-five patients (incidence, 30.1%) developed complications of orthostatic hypotension (OH) in the "off state" and best "on state," respectively. Mild cognitive impairment was a risk factor for OH occurrence in the "off state." The OH occurrence in the best "on state" was associated with OH in the "off state" and urinary incontinence.

Conclusion

Our findings suggest that 250 mg or more of levodopa/benserazide could significantly reduce BP and orthostatic effect in older patients with PD in the early and middle stages. Therefore, they should routinely monitor their BP.

Trial registration number

ChiCTR2200055707.

Age as a risk factor for orthostatic hypotension induced by the levodopa challenge test in patients with Parkinson's disease: Results from a single-center trial

BACKGROUND

Hypotension can occur in patients receiving levodopa (L-dopa) treatment for parkinsonism. However, only few studies have focused on the characteristics of orthostatic hypotension (OH) induced by the L-dopa challenge test (LCT). This study aimed to investigate the characteristics and influencing factors of LCT-induced OH in a relatively large sample of patients with Parkinson's disease (PD).

METHODS

Seventy-eight patients with PD without a previous diagnosis of OH underwent the LCT. Blood pressure (BP) in the supine and standing positions was measured before and 2 hours after the LCT. If diagnosed with OH, the patients' BP was monitored again 3 hours after the LCT. The clinical features and demographics of the patients were analyzed.

RESULTS

Eight patients were diagnosed with OH 2 hours after the LCT (median dose of 375 mg L-dopa/benserazide; incidence = 10.3%). One patient without symptoms had OH 3 hours after the LCT. Compared with patients without OH, patients with OH had lower 1- and 3-minutes standing systolic BP and 1-minute standing diastolic BP at baseline and 2 hours after the LCT. Patients in the OH group were of older age (65.31 ± 4.17 years vs 59.74 ± 5.55years) and had lower Montreal Cognitive Assessment scores (17.5 vs 24) and higher L-dopa/benserazide levels (375 [250, 500] mg vs 250 [125, 500] mg). Older age markedly increased the odds of having LCT-induced OH (odds ratio, 1.451; 95% confidence interval, 1.055-1.995; P = .022).

CONCLUSIONS

LCT increased the odds of OH in non-OH PD, causing symptomatic OH in 10.3% of patients in our study, thereby raising safety concerns. Increase in age was observed to be a risk factor for LCT-induced OH in PD patients. A study with a larger sample size is warranted to confirm our results.

TRIAL REGISTRATION NUMBER

Clinical Trials Registry under ChiCTR2200055707.

DATE OF REGISTRATION

January 16, 2022.

Parkinson's disease and cardiovascular involvement: Edifying insights (Review)

Parkinson's disease (PD) is one of the most common neurodegenerative illnesses, and is a major healthcare burden with prodigious consequences on life-quality, morbidity, and survival. Cardiovascular diseases are the leading cause of mortality worldwide and growing evidence frequently reports their co-existence with PD. Cardiac dysautonomia due to autonomic nervous system malfunction is the most prevalent type of cardiovascular manifestation in these patients, comprising orthostatic and postprandial hypotension, along with supine and postural hypertension. Moreover, many studies have endorsed the risk of patients with PD to develop ischemic heart disease, heart failure and even arrhythmias, but the underlying mechanisms are not entirely clear. As importantly, the medication used in treating PD, such as levodopa, dopamine agonists or anticholinergic agents, is also responsible for cardiovascular adverse reactions, but further studies are required to elucidate the underlying mechanisms. The purpose of this review was to provide a comprehensive overview of current available data regarding the overlapping cardiovascular disease in patients with PD.

Orthostatic Hypotension and Antiparkinsonian Drugs: A Systematic Review and Meta-analysis

BACKGROUND

Orthostatic hypotension (OH) is multifactorial in Parkinson's disease (PD). Antiparkinsonian medication can contribute to OH, leading to increased risk of falls, weakness and fatigue.

METHODS

We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) of antiparkinsonian drugs associated with OH as an adverse effect, compared to placebo. We searched EMBASE, MEDLINE and Web of Science databases until November 2020. Analysis used fixed-effects models and the GRADE tool to rate quality of evidence. Meta-analysis was performed if 3 or more studies of a drug group were available.

RESULTS

Twenty-one RCTs including 3783 patients were included comparing 6 PD drug groups to placebo (MAO-B inhibitors, dopamine agonists, levodopa, COMT inhibitors, levodopa and adenosine receptor antagonists). OH was recorded as an adverse event or measurement of vital signs, without further specification on how this was defined or operationalised. Meta-analysis was performed for MAO-B inhibitors and dopamine agonists, as there were 3 or more studies for these drug groups. In this analysis, compared with placebo, neither MAO-B inhibitors or dopamine agonists were associated with increased risk of OH, (OR 2.28 [95% CI:0.81-6.46]), (OR 1.39 [95% CI:0.97-1.98]).

CONCLUSIONS

Most studies did not specifically report OH, or reporting of OH was limited, including how and when it was measured. Furthermore, studies specifically reporting OH included participants that were younger than typical PD populations without multimorbidity. Future trials should address this, for example,, by including individuals over the age of 75, to improve estimations of how antiparkinsonian medications affect risk of OH.

Central Aortic Pressure and Arterial Stiffness in Parkinson’s Disease: A Comparative Study

Background

Cardiovascular autonomic dysfunction, which leads to hemodynamic disorders, is commonly observed in patients with Parkinson's disease (PD). Central aortic pressure (CAP) is the systolic blood pressure (SBP) at the root of the aorta. In young people, CAP is lower than peripheral arterial blood pressure. In older people, the difference between CAP and peripheral arterial blood pressure decreases depending on the extent of arterial stiffness (AS). In patients with AS, CAP increases. CAP is thus regarded as an indicator of AS.

Objective

To compare CAP and other hemodynamic parameters for AS between patients with Parkinson's disease and control group. We also aimed to evaluate changes in these hemodynamic parameters after the levodopa (LD) intake.

Methods

We included 82 patients with PD and 76 healthy controls. Age, sex, disease duration, disease subtype, Hoehn–Yahr stage (H&Y), and nonmotor symptoms (NMS) were documented. TensioMed Software v.3.0.0.1 was used to measure CAP, peripheral arterial blood pressure, pulse pressure (PP), heart rate (HR), mean arterial pressure (MAP), augmentation index (AI), pulse wave velocity, and ejection time. All patients were being treated with LD, and measurements were performed 1 h before and 1 h after LD intake.

Results

Baseline peripheral arterial blood pressure and CAP values were significantly higher in the PD group than in the control group (p < 0.001 and p=0.02, respectively). Most cardiac hemodynamic parameters, including peripheral arterial blood pressure and CAP, decreased significantly (p < 0.02 and p < 0.001, respectively) after LD intake in the PD group. Disease subtype, duration, and severity did not affect any of the hemodynamic parameters. When NMS were evaluated, patients with psychosis and dementia showed higher baseline parameters.

Conclusion

Loss of postganglionic noradrenergic innervation is well-known with PD. Several cardiac hemodynamic parameters were affected, suggesting cardiac autonomic dysfunction in these patients. The data obtained were independent of disease severity, duration, and subtype. After LD intake, most of these parameters decreased, which might have a positive effect on the vascular burden.

Practical pearls to improve the efficacy and tolerability of levodopa in Parkinson's disease

INTRODUCTION

Levodopa is the most effective medication for the treatment of motor symptoms of Parkinson's disease (PD). Several factors may affect the efficacy and tolerability of levodopa. These include the timing, dosage and administration of levodopa, concomitant drugs, food, PD-associated non motor symptoms, and various neurologic and non-neurologic comorbidities. If not appropriately addressed, these issues may limit levodopa efficacy, tolerability, and compliance.

AREAS COVERED

This article reviews the basics of the metabolism of orally administered levodopa, its side effects, and the factors that may affect its tolerability and efficacy. We provide several practical pearls to improve the tolerability and efficacy of levodopa.

EXPERT OPINION

Protein-rich food delays and reduces levodopa absorption. Hence, levodopa should preferably be administered in a relatively empty stomach. Carbidopa dosing is crucial as it not only enhances the entry of levodopa into the central nervous system, but also reduces levodopa's peripheral adverse effects. Patients experiencing the early side effects such as nausea/vomiting should be prescribed with anti-nausea medications that do not block dopamine receptors. Non-oral routes of administration can be used to obviate persistent gastrointestinal side effects. Implementation of these and other tips may help improve the tolerability and efficacy of levodopa.

Dysautonomia in Parkinson’s Disease: Impact of Glucocerebrosidase Gene Mutations on Cardiovascular Autonomic Control

Evidence from clinical practice suggests that PD patients with the Glucocerebrosidase gene mutations (GBA-PD) are characterized by more severe dysautonomic symptoms than patients with idiopathic PD (iPD). Therefore, an accurate assessment of cardiovascular autonomic control (CAC) is necessary to clarify the role of GBA mutations in the pathophysiology of PD. We evaluated the CAC at rest and during orthostatic challenge of 15 iPD, 15 GBA-PD and 15 healthy controls (CTR). ECG and respiration were recorded in supine position and during active standing. The analysis of Heart Rate Variability (HRV) was performed on ECG recordings using two different approaches, linear spectral analysis and non-linear symbolic analysis. GBA-PD patients presented more frequently an akinetic-rigid phenotype and cognitive dysfunction than iPD patients. Both iPD and GBA-PD group were characterized by a lower spectral HRV than CTR group. At rest, the GBA-PD group was characterized by a lower parasympathetic modulation and a shift of the sympathovagal balance toward a sympathetic predominance compared to the CTR group. Moreover, the GBA-PD patients presented a lower HR increment and a lower or absent reduction of the vagal modulation in response to the active standing than iPD patients. Lastly, the cardiovascular autonomic dysfunction in PD patients was associated with longer disease duration, and with the occurrence of REM sleep behavior disorder and constipation. Our findings suggest a more severe impairment of the CAC in PD patients with GBA mutations. These results and further studies on the role of GBA mutations could allow a stratification based on cardiovascular risk in PD patients and the implementation of specific prevention programs.

Effect of Acute Levodopa Up-Titration on Blood Pressure in Patients With Early Stage Parkinson's Disease: Results of a Levodopa Challenge Test

Objective: Levodopa up-titration is the primary therapeutic strategy as the Parkinson’s disease (PD) progresses. However, the effects of levodopa up-titration on blood pressure (BP) are inconclusive. This study aimed to investigate the effect of acute levodopa up-titration simulated by levodopa challenge test (LCT) on BP in patients with early stage PD.

Methods: We monitored BP in 52 patients with early stage PD using a standardized standing test. BP was assessed in supine position after 10 min of rest and at 1 and 3 min after standing up. BP was measured in the “off-state” and the best “on-state” during LCT in the morning at hospital. In another day, “off-state” and the best “on-state” BP was measured before and after anti-PD drug uptake in the morning at home. Demographic and clinical features of the patients were evaluated and analyzed.

Results: In the LCT, the prevalence of OH in the “off-state” and the best “on-state” was 11.5 and 13.5%, respectively. Additionally, the OH in the best “on-state” was associated with OH in the “off-state” and monoamine oxidase B inhibitor use. Although 38 (73.1%) patients experienced levodopa-induced hypotension during the LCT, no risk factors were identified. While BP reductions were observed after taking anti-PD drugs at home, no further reduction was seen during acute levodopa up-titration simulated by the LCT.

Conclusion: Our results demonstrate that acute levodopa up-titration does not exacerbate BP reduction induced by anti-PD drugs at home. BP monitoring is critical for the management of patients with PD.

OUP accepted manuscript

The gut microbiota is considered a key ‘metabolic organ’. Its metabolic activities play essential roles complementary to the host metabolic functions. The interplays between gut microbes and commonly used non-antibiotic drugs have garnered substantial attention over the years. Drugs can reshape the gut microorganism communities and, vice versa, the diverse gut microbes can affect drug efficacy by altering the bioavailability and bioactivity of drugs. The metabolism of drugs by gut microbial action or by microbiota–host cometabolism can transform the drugs into various metabolites. Secondary metabolites produced from the gut microbial metabolism of drugs contribute to both the therapeutic benefits and the side effects. In view of the significant effect of the gut microbiota on drug efficiency and clinical outcomes, it is pivotal to explore the interactions between drugs and gut microbiota underlying medical treatments. In this review, we describe and summarize the complex bidirectional interplays between gut microbes and drugs. We also illustrate the gut-microbiota profile altered by non-antibiotic drugs, the impacts and consequences of microbial alteration, and the biochemical mechanism of microbes impacting drug effectiveness. Understanding how the gut microbes interact with drugs and influence the therapeutic efficacy will help in discovering diverse novel avenues of regulating the gut microbes to improve the therapeutic effects and clinical outcomes of a drug in precision.

Cardiac Changes in Parkinson's Disease: Lessons from Clinical and Experimental Evidence

Dysautonomia is a common non-motor symptom in Parkinson's disease (PD). Most dysautonomic symptoms appear due to alterations in the peripheral nerves of the autonomic nervous system, including both the sympathetic and parasympathetic nervous systems. The degeneration of sympathetic nerve fibers and neurons leads to cardiovascular dysfunction, which is highly prevalent in PD patients. Cardiac alterations such as orthostatic hypotension, heart rate variability, modifications in cardiogram parameters and baroreflex dysfunction can appear in both the early and late stages of PD, worsening as the disease progresses. In PD patients it is generally found that parasympathetic activity is decreased, while sympathetic activity is increased. This situation gives rise to an imbalance of both tonicities which might, in turn, promote a higher risk of cardiac damage through tachycardia and vasoconstriction. Cardiovascular abnormalities can also appear as a side effect of PD treatment: L-DOPA can decrease blood pressure and aggravate orthostatic hypotension as a result of a negative inotropic effect on the heart. This unwanted side effect limits the therapeutic use of L-DOPA in geriatric patients with PD and can contribute to the number of hospital admissions. Therefore, it is essential to define the cardiac features related to PD for the monitorization of the heart condition in parkinsonian individuals. This information can allow the application of intervention strategies to improve the course of the disease and the proposition of new alternatives for its treatment to eliminate or reverse the motor and non-motor symptoms, especially in geriatric patients.

Cardiac tyrosine hydroxylase activation and MB-COMT in dyskinetic monkeys

The impact of age-associated disorders is increasing as the life expectancy of the population increments. Cardiovascular diseases and neurodegenerative disorders, such as Parkinson's disease, have the highest social and economic burden and increasing evidence show interrelations between them. Particularly, dysfunction of the cardiovascular nervous system is part of the dysautonomic symptoms of Parkinson's disease, although more studies are needed to elucidate the role of cardiac function on it. We analyzed the dopaminergic system in the nigrostriatal pathway of Parkinsonian and dyskinetic monkeys and the expression of some key proteins in the metabolism and synthesis of catecholamines in the heart: total and phosphorylated (phospho) tyrosine hydroxylase (TH), and membrane (MB) and soluble (S) isoforms of catechol-O-methyl transferase (COMT). The dopaminergic system was significantly depleted in all MPTP-intoxicated monkeys. MPTP- and MPTP + L-DOPA-treated animals also showed a decrease in total TH expression in both right (RV) and left ventricle (LV). We found a significant increase of phospho-TH in both groups (MPTP and MPTP + L-DOPA) in the LV, while this increase was only observed in MPTP-treated monkeys in the RV. MB-COMT analysis showed a very significant increase of this isoform in the LV of MPTP- and MPTP + L-DOPA-treated animals, with no significant differences in S-COMT levels. These data suggest that MB-COMT is the main isoform implicated in the cardiac noradrenergic changes observed after MPTP treatment, suggesting an increase in noradrenaline (NA) metabolism. Moreover, the increase of TH activity indicates that cardiac noradrenergic neurons still respond despite MPTP treatment.

Dopamine Modulates Drosophila Gut Physiology, Providing New Insights for Future Gastrointestinal Pharmacotherapy

Dopamine has a variety of physiological roles in the gastrointestinal tract (GI) through binding to Drosophila dopamine D1-like receptors (DARs) and/or adrenergic receptors and has been confirmed as one of the enteric neurotransmitters. To gain new insights into what could be a potential future promise for GI pharmacology, we used Drosophila as a model organism to investigate the effects of dopamine on intestinal physiology and gut motility. GAL4/UAS system was utilized to knock down specific dopamine receptors using specialized GAL4 driver lines targeting neurons or enterocytes cells to identify which dopamine receptor controls stomach contractions. DARs (Dop1R1 and Dop1R2) were shown by immunohistochemistry to be strongly expressed in all smooth muscles in both larval and adult flies, which could explain the inhibitory effect of dopamine on GI motility. Adult males' gut peristalsis was significantly inhibited by knocking down dopamine receptors Dop1R1, Dop1R2, and Dop2R, but female flies' gut peristalsis was significantly repressed by knocking down only Dop1R1 and Dop1R2. Our findings also showed that dopamine drives PLC-β translocation from the cytoplasm to the plasma membrane in enterocytes for the first time. Overall, these data revealed the role of dopamine in modulating Drosophila gut physiology, offering us new insights for the future gastrointestinal pharmacotherapy of neurodegenerative diseases associated with dopamine deficiency.

Diagnosis and Management of Pain in Parkinson's Disease: A New Approach

Pain is a frequent and disabling non-motor feature of Parkinson's disease (PD). The recently proposed PD Pain Classification System (PD-PCS) allows for an association of pain with PD to be determined before being allocated to the main pain mechanism (i.e. nociceptive, neuropathic, and nociplastic). In this article, previous studies on treatments for pain in PD are summarized according to the pain mechanisms. A mechanistic approach to treatment is discussed. We suggest that the first step should be optimizing dopaminergic therapy before other therapy is started. When these treatments remain unsuccessful, further causes of pain must be considered. The role of drugs, invasive treatments, and physiotherapeutic interventions are discussed with a focus on older PD patients and considering polypharmacy, altered pharmacokinetics, and comorbidities.

Increased atrial fibrillation risk in Parkinson's disease: A nationwide population-based study

OBJECTIVE

Parkinson's disease (PD) is the second most common neurodegenerative disorder associated with various morbidities. Although the relationship between cardiovascular disease and PD has been studied, a paucity of information on PD and atrial fibrillation (AF) association exists. Thus, we aimed to investigate whether patients with PD have an increased risk of AF.

METHODS

This study included 57,585 patients with newly diagnosed PD (≥40-year-old, mean age 69.7 years, men 40.2%) and without a history of AF from the Korean National Health Insurance Service (NHIS) database between 2010 and 2015. Furthermore, an equal number of age- and sex-matched subjects without PD were selected for comparison. The primary outcome was new-onset AF.

RESULTS

During the mean follow-up period of 3.4 ± 1.8 years, AF was newly diagnosed in 3,665 patients. A significantly higher incidence rate of AF was noted among patients with PD than among patients without PD (10.75 and 7.86 per 1000 person-year, respectively). Multivariate Cox-regression analysis revealed that PD was an independent risk factor for AF (hazard ratio [HR]: 1.27, 95% confidence interval [CI]: 1.18-1.36). Furthermore, subgroup analyses revealed that AF risk was higher in the younger age subgroups, and compared with the non-PD group, the youngest PD group (age: 40-49 years) had a threefold increased risk of AF (HR: 3.06, 95% CI: 1.20-7.77).

INTERPRETATION

Patients with PD, especially the younger age subgroups, have an increased risk of AF. Active surveillance and management of AF should be considered to prevent further complications.

24-Hour Levodopa-Carbidopa Intestinal Gel: Clinical Experience and Practical Recommendations

Infusion of levodopa-carbidopa intestinal gel (LCIG; also designated carbidopa-levodopa enteral suspension) for 16 hours is a standard treatment for patients with advanced Parkinson's disease, and clinical observations suggest that 24-hour LCIG infusion may further reduce symptoms. This review provides practical advice on the management of patients transitioning to 24-hour LCIG infusion. We review available clinical data for 24-hour infusion and discuss adjustments to dosing, recommendations for monitoring, and management of patient concerns, based on our clinical experience. Data from multiple studies suggest that LCIG may improve non-motor symptoms. Although few studies have examined 24-hour LCIG infusion, available data indicate that certain patients may benefit from around-the-clock treatment. Studies of 24-hour LCIG infusion are limited by small sample sizes and open-label study designs, which may hamper translation to clinical practice. In our experience, we have found that patients may benefit from 24-hour infusion when reductions in nocturnal symptoms and improvements to quality of sleep are needed. Levodopa-unresponsive freezing of gait or poorly controlled troublesome dyskinesias may also indicate a patient may benefit from 24-hour infusion. Dose adjustments, especially of the nocturnal rate, are typically necessary and, as with 16-hour infusion, patients should be monitored for autonomic dysfunction; overnight wearing off symptoms; weight changes; fluctuations in plasma levels of vitamins B₆/B₁₂, folate, and homocysteine; changes in sleep patterns; or worsening of hallucinations, delusions, and/or nightmares. Available data and our clinical experience suggest that 24-hour LCIG may be warranted among selected patients who have poorly controlled nocturnal fluctuations or early morning "off" symptoms.

Non-Coding RNAs in the Brain-Heart Axis: The Case of Parkinson's Disease

Parkinson's disease (PD) is a complex and heterogeneous disorder involving multiple genetic and environmental influences. Although a wide range of PD risk factors and clinical markers for the symptomatic motor stage of the disease have been identified, there are still no reliable biomarkers available for the early pre-motor phase of PD and for predicting disease progression. High-throughput RNA-based biomarker profiling and modeling may provide a means to exploit the joint information content from a multitude of markers to derive diagnostic and prognostic signatures. In the field of PD biomarker research, currently, no clinically validated RNA-based biomarker models are available, but previous studies reported several significantly disease-associated changes in RNA abundances and activities in multiple human tissues and body fluids. Here, we review the current knowledge of the regulation and function of non-coding RNAs in PD, focusing on microRNAs, long non-coding RNAs, and circular RNAs. Since there is growing evidence for functional interactions between the heart and the brain, we discuss the benefits of studying the role of non-coding RNAs in organ interactions when deciphering the complex regulatory networks involved in PD progression. We finally review important concepts of harmonization and curation of high throughput datasets, and we discuss the potential of systems biomedicine to derive and evaluate RNA biomarker signatures from high-throughput expression data.

Effects of Medical Comorbidities on the Surgical Outcomes of Deep Brain Stimulation for Parkinson Disease: A Retrospective, Single-Institution Study

OBJECTIVE

Advancing age and greater number of medical comorbidities are well-known risk factors for higher rates of surgical complications and undesirable outcomes. We sought to determine the risk of increasing medical comorbidities on surgical outcomes for patients with Parkinson disease undergoing deep brain stimulation (DBS) surgery.

METHODS

We retrospectively reviewed 107 consecutive patients who underwent DBS for Parkinson disease at Ochsner Medical Center in 2008-2018. Patients were stratified into 3 groups based on Elixhauser comorbidity index (ECI) at the time of surgery: 0, 1, or ≥2. Outcome measures were changes in Unified Parkinson's Disease Rating Scale III scores, changes in medications, and surgical complications. Analysis of variance, paired t test, and nonparametric equivalents were used for statistical analysis.

RESULTS

Of patients, 31 (29.0%) had ECI score 0, 44 (41.1%) had ECI score 1, and 32 (29.9%) had ECI score ≥2. For all groups, Unified Parkinson's Disease Rating Scale III scores decreased significantly postoperatively (P = 0.0014, P < 0.0001, P < 0.0001). All groups had a reduction in mean levodopa equivalent daily dose after surgery; however, only the group with ≥2 comorbidities achieved statistical significance (P = 0.0026). The rate of postoperative complications was significantly correlated with comorbidity score on univariate logistic regression analysis (P = 0.0425).

CONCLUSIONS

Our findings indicate that DBS is efficacious in patients with multiple medical comorbidities. However, patients with ≥1 medical comorbidities may be more likely to have complications. The most common observed complication was wound infection. Patients with medical comorbidities may still benefit significantly from DBS when performed at experienced centers.

Nocturnal blood pressure changes in Parkinson's disease: correlation with autonomic dysfunction and vitamin D levels

Nocturnal blood pressure (BP) changes are an indicator of autonomic dysfunction. We aim to investigate the correlation between nocturnal blood pressure (BP) variability, vitamin D levels and Parkinson's disease severity (PD) in this study. Thirty-five patients with PD participated in the study. Disease severity was evaluated by United Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr Scale (HYS). Equivalent levodopa dose was calculated and 25-hydroxyvitamin D levels were measured. The Non-Motor Symptom Questionnaire (NMSQ) was applied to all patients. Ambulatory BP monitoring for 24 h was established. Patients were divided into three groups according to nocturnal BP results: dippers (normal finding-a decline in mean nighttime BP of more than 10%); non-dippers (pathological-a decline in mean nighttime BP of less than 10%); reverse dippers (pathological-an increase in mean nighttime BP) .The mean score of the NMSQ was higher in the group with HYS > 2 (p = 0.050). Four patients were dipper, 17 patients were non-dipper and 16 patients were reverse dipper. There was no significant difference between the three groups in terms of age, gender, disease duration, age of the disease onset, disease stage, disease duration, dopamine agonist usage, levodopa equivalent dose, vitamin D level and NMSQ scores. NMSQ scores are high in advanced PD. Ambulatory BP monitoring is useful in detecting autonomic dysfunction. The number of patients with non-dipping and reverse dipping is high in PD, independent from PD severity, drug dose, vitamin D and the other NMS symptoms.

Using Deep Brain Stimulation to Unravel the Mysteries of Cardiorespiratory Control

This article charts the history of deep brain stimulation (DBS) as applied to alleviate a number of neurological disorders, while in parallel mapping the electrophysiological circuits involved in generating and integrating neural signals driving the cardiorespiratory system during exercise. With the advent of improved neuroimaging techniques, neurosurgeons can place small electrodes into deep brain structures with a high degree accuracy to treat a number of neurological disorders, such as movement impairment associated with Parkinson's disease and neuropathic pain. As well as stimulating discrete nuclei and monitoring autonomic outflow, local field potentials can also assess how the neurocircuitry responds to exercise. This technique has provided an opportunity to validate in humans putative circuits previously identified in animal models. The central autonomic network consists of multiple sites from the spinal cord to the cortex involved in autonomic control. Important areas exist at multiple evolutionary levels, which include the anterior cingulate cortex (telencephalon), hypothalamus (diencephalon), periaqueductal grey (midbrain), parabrachial nucleus and nucleus of the tractus solitaries (brainstem), and the intermediolateral column of the spinal cord. These areas receive afferent input from all over the body and provide a site for integration, resulting in a coordinated efferent autonomic (sympathetic and parasympathetic) response. In particular, emerging evidence from DBS studies have identified the basal ganglia as a major sub-cortical cognitive integrator of both higher center and peripheral afferent feedback. These circuits in the basal ganglia appear to be central in coupling movement to the cardiorespiratory motor program. © 2020 American Physiological Society. Compr Physiol 10:1085-1104, 2020.

Cardiac Noradrenaline Turnover and Heat Shock Protein 27 Phosphorylation in Dyskinetic Monkeys

BACKGROUND

Autonomic dysfunction is a well-known dominant symptom in the advanced stages of Parkinson's disease. However, the role of cardiac sympathetic nerves still needs to be elucidated.

OBJECTIVES

To evaluate cardiac sympathetic response in Parkinsonian and dyskinetic monkeys.

METHODS

Adult male monkeys were divided into 1 of the following 3 groups: controls, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated monkeys, and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine+levodopa-treated animals. Noradrenaline, its metabolite normetanephrine, and phospho-Heat shock proten 27 (p-Hsp27) at serine 82 levels were analyzed in the left and right ventricles of the heart. Tyrosine hydroxylase immunohistochemistry was performed in the ventral mesencephalon.

RESULTS

The results were the following: (1) 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intoxication significantly increased normetanephrine levels and decreased noradrenaline turnover in the right ventricle without changes in the left ventricle; however, (2) levodopa treatment decreased noradrenaline levels and enhanced the normetanephrine/noradrenaline ratio in parallel with a very significant increase of Hsp27 activity in both ventricles.

CONCLUSIONS

Levodopa treatment could induce protective cardiac effects through the increased Hsp27 activity. © 2019 International Parkinson and Movement Disorder Society.

Effectiveness and safety of topical levodopa in a chick model of myopia

Animal models have demonstrated a link between dysregulation of the retinal dopamine system and the excessive ocular growth associated with the development of myopia. Here we show that intravitreal or topical application of levodopa, which is widely used in the treatment of neurological disorders involving dysregulation of the dopaminergic system, inhibits the development of experimental myopia in chickens. Levodopa slows ocular growth in a dose dependent manner in chicks with a similar potency to atropine, a common inhibitor of ocular growth in humans. Topical levodopa remains effective over chronic treatment periods, with its effectiveness enhanced by coadministration with carbidopa to prevent its premature metabolism. No changes in normal ocular development (biometry and refraction), retinal health (histology), or intraocular pressure were observed in response to chronic treatment (4 weeks). With a focus on possible clinical use in humans, translation of these avian safety findings to a mammalian model (mouse) illustrate that chronic levodopa treatment (9 months) does not induce any observable changes in visual function (electroretinogram recordings), ocular development, and retinal health, suggesting that levodopa may have potential as a therapeutic intervention for human myopia.

Reduced central sympathetic activity in Parkinson's disease

OBJECTIVE

With a combination of different sympathetic tests, we aimed to elucidate whether impairment of sympathetic function in Parkinson's disease (PD) is the consequence of a central or peripheral efferent dysfunction.

METHODS

Thirty-five patients with early-to-intermediate PD (median age: 63 years; IQR: 57-67 years; disease duration 1-9 years, 15 women) and 20 age- and sex-matched healthy controls (median age: 64.5 years; IQR: 58-68 years; 10 women) were recruited. Autonomic testing was performed in two subgroups and included the assessment of resting cardiovascular parameters, postprandial hypotension (PPH), orthostatic hypotension (OH), and vasoconstriction induced by intradermal microdialysis with different concentrations of norepinephrine (NE; 10^-5 ; 10^-6 ; 10^-7 ; 10^-8 ) and by cold through forehead cooling. We also used sympathetic multiunit microneurography (muscle sympathetic nerve activity; MSNA; burst frequency (BF): bursts per minute; burst incidence (BI): bursts per 100 heart beats) and evaluated the presence of phosphorylated α-synuclein deposits in skin innervation in biopsies from the thighs by immunohistohemistry.

RESULTS

Diastolic blood pressure was higher in the PD group at rest (p < .001) and during OH (F = 6.533; p = .022). Vasoconstriction induced by NE microdialysis and cold was unchanged in PD patients. MSNA was lower in PD patients than in controls (BF: p = .001; BI: p = .025). Phosphorylated α-synuclein deposits could be found only in PD patients.

CONCLUSION

We did not find indications for peripheral sympathetic nerve fiber dysfunction or adrenoreceptor sensitivity changes. The decreased MSNA argues in favor of central sympathetic impairment.

Falls in Synucleinopathies

Parkinson's disease (PD) and other synucleinopathies, namely dementia with Lewy bodies (DLB) and multiple system atrophy (MSA), are common degenerative neurological disorders that share synuclein pathology. Although certain cardinal features of parkinsonism, including bradykinesia and rigidity, respond well to levodopa, axial features, such as gait and balance impairment, are less reliably responsive to dopaminergic therapy and surgical interventions. Consequently, falls are common in PD and other synucleinopathies and are a major contributor toward injury and loss of independence. This underscores the need for appropriate fall risk assessment and implementation of preventative measures in all patients with parkinsonism. The aim of this review is therefore to explore modifiable and non-modifiable risk factors for falls in synucleinopathies. We next review and evaluate the evidence for pharmacological, nonpharmacological, and surgical approaches for fall prevention, and emphasize individualized and multifaceted approaches.

Orthostatic hypotension following deep brain stimulation in parkinson's disease: a systematic review

Background: Deep brain stimulation (DBS) is a treatment that may be suitable for patients with Parkinson's disease (PD) with severe motor fluctuations and/or dyskinesias despite optimised medical therapy. DBS has been associated with side effects including deterioration in cognition, verbal fluency and mood. Studies assessing the effect of DBS on orthostatic hypotension (OH) have produced variable results.Objectives: The aim is to summarise peer-reviewed studies that have assessed the effect of DBS on systolic or diastolic BP in PD patients.Methods: The databases PubMed, EMBASE, Medline and Scopus were searched using the terms (Deep brain stimulation OR DBS) AND (hypotension OR hypertension OR blood pressure) on 13 April 2017.Results: Fourteen studies fulfilled the inclusion criteria. Ten studies involved subthalamic nucleus (STN) DBS, three studies globus pallidus interna (GPi) DBS and one study involved DBS of the pedunculopontine nuclei and motor thalamus. The majority of the studies found results indicating that DBS in PD does not worsen OH in PD.Conclusions: Small sample sizes and lack of blinding of outcome assessors means this result should be approached cautiously. Future research may further investigate the effect of GPi DBS on OH and should aim to address these methodological issues.

Stroke and Coronary Artery Disease Are Associated With Parkinson’s Disease

Background: The relationship between vascular disease and Parkinson’s disease (PD) is controversial. We performed a cross-sectional study to investigate the association of two common vascular diseases (stroke and coronary artery disease [CAD]) with Parkinson’s disease. Methods: We identified 63 and 62 PD cases in two population-based cohorts (Malu rural community and Wuliqiao urban community) and collected information of PD and non-PD by means of questionnaires. Logistic regression analysis was used to investigate the association between stroke, coronary artery disease and PD, after adjusting for age, sex, hypertension, diabetes mellitus, hypercholesterolemia, smoking status, alcohol consumption, tea consumption and body mass index. Results: After adjustment for potential confounders, we found that CAD and stroke were associated with PD in the Malu rural community (CAD: odds ratio [OR]=7.11, 95% confidence intervals [CI]: 3.09-16.40, p<0.001; stroke: OR=6.77, 95% CI: 3.09-14.81, p<0.001) and stroke was associated with PD in the Wuliqiao urban community (OR=2.58, 95% CI: 1.36-4.89, p=0.004), especially in women. In a subgroup analysis of PD with age- and sex-matched controls, the results were similar in the Malu rural community (CAD: OR=12.72, 95% CI: 2.92-55.32, p=0.001; stroke: OR=6.26, 95% CI: 1.83-21.42, p=0.003), whereas in the Wuliqiao urban community the results were different in that CAD (but not stroke) was found to be associated with PD (CAD: OR=2.44, 95% CI: 1.09-5.47, p=0.03; stroke: OR=1.79, 95% CI: 0.77-4.17, p=0.18). Conclusions: Our study suggested that stroke and CAD are associated with PD in two Chinese population-based cohorts, indicating a probable vascular component in the pathogenesis of PD.

The influence of vascular risk factors on cognitive function in early Parkinson's disease

OBJECTIVES

Hypertension, dyslipidemia, diabetes, and obesity are well-established risk factors for cognitive impairment and dementia in older adults. In contrast, previous studies that have assessed the impact of vascular risk factors (VRFs) on cognition in Parkinson's disease (PD) have had methodological limitations and reported conflicting findings. We address this question in a large well-characterized cohort of de novo PD patients.

METHODS

A total of 367 untreated and non-demented patients aged 50 years and older with early PD (H&Y = 1.0-2.0) underwent a comprehensive clinical and neuropsychological assessment at baseline and 24 months later. A series of linear mixed models were used to determine the effects of VRFs on cognition while controlling for patient and disease characteristics. The outcomes included norm-referenced Z-scores of global cognition, visuospatial skills, verbal episodic memory, semantic verbal fluency, attention, and working memory tests.

RESULTS

A longer history of hypertension and a higher pulse pressure were significant predictors of lower Z-scores on immediate and delayed free recall, recognition, and verbal fluency tests. On average, every 10 mmHg increase in pulse pressure was associated with a 0.08 reduction on the cognitive Z-scores. The effects were independent of age, education, disease duration, motor impairment, medication, and depressive symptoms. Other VRFs were not associated with cognitive outcomes.

CONCLUSIONS

Our results are consistent with previous studies suggesting that hypertension exerts a detrimental effect on memory and verbal fluency in early PD. Management of blood pressure and cardiovascular health may be important to reduce risk of cognitive decline in PD. Copyright © 2017 John Wiley & Sons, Ltd.

Dopaminergic Therapy Increases Go Timeouts in the Go/No-Go Task in Patients with Parkinson's Disease

Parkinson's disease (PD) is characterized by resting tremor, rigidity and bradykinesia. Dopaminergic medications such as L-dopa treat these motor symptoms, but can have complex effects on cognition. Impulse control is an essential cognitive function. Impulsivity is multifaceted in nature. Motor impulsivity involves the inability to withhold pre-potent, automatic, erroneous responses. In contrast, cognitive impulsivity refers to improper risk-reward assessment guiding behavior. Informed by our previous research, we anticipated that dopaminergic therapy would decrease motor impulsivity though it is well known to enhance cognitive impulsivity. We employed the Go/No-go paradigm to assess motor impulsivity in PD. Patients with PD were tested using a Go/No-go task on and off their normal dopaminergic medication. Participants completed cognitive, mood, and physiological measures. PD patients on medication had a significantly higher proportion of Go trial Timeouts (i.e., trials in which Go responses were not completed prior to a deadline of 750 ms) compared to off medication (p = 0.01). No significant ON-OFF differences were found for Go trial or No-go trial response times (RTs), or for number of No-go errors. We interpret that dopaminergic therapy induces a more conservative response set, reflected in Go trial Timeouts in PD patients. In this way, dopaminergic therapy decreased motor impulsivity in PD patients. This is in contrast to the widely recognized effects of dopaminergic therapy on cognitive impulsivity leading in some patients to impulse control disorders. Understanding the nuanced effects of dopaminergic treatment in PD on cognitive functions such as impulse control will clarify therapeutic decisions.

Subthalamic nucleus stimulation and levodopa modulate cardiovascular autonomic function in Parkinson's disease

We aimed to explore the effects of bilateral subthalamic nucleus stimulation and levodopa on cardiovascular autonomic function in Parkinson’s disease. Twenty-six Parkinson’s disease patients with bilateral subthalamic nucleus stimulation in a stable state were tested under stimulation off and dopaminergic medication off (OFF-OFF), stimulation on and dopaminergic medication off (ON-OFF), and stimulation on and medication (levodopa) on (ON-ON) conditions by recording continuously blood pressure, ECG, and respiration at rest, during metronomic deep breathing, and head-up tilt test. Thirteen patients were diagnosed as orthostatic hypotension by head-up tilt test. Baroreflex sensitivity and spectral analyses were performed by trigonometric regressive spectral analysis. Subthalamic nucleus stimulation and levodopa had multiple influences. (1) Systolic blood pressure during tilt-up was reduced by subthalamic nucleus stimulation, and then further by levodopa. (2) Subthalamic nucleus stimulation and levodopa had different effects on sympathetic and parasympathetic regulations in Parkinson’s disease. (3) Levodopa decreased baroreflex sensitivity and RR interval only in the orthostatic hypotension group, and had opposite effects on the non-orthostatic hypotension group. These findings indicate that subthalamic nucleus stimulation and levodopa have different effects on cardiovascular autonomic function in Parkinson’s disease, which are modulated by the presence of orthostatic hypotension as well.

Dopaminergic Therapies for Non-motor Symptoms in Parkinson's Disease

Apart from the typical motor symptoms, Parkinson's disease is characterized by a wide range of different non-motor symptoms, which are highly prevalent in all stages of the disease and have an incisive influence on quality of life. Moreover, their treatment continues to be challenging. In this review, we critically summarize the evidence for the impact of dopaminergic therapies on non-motor symptoms in Parkinson's disease. We performed a PubMed search to identify relevant clinical studies that investigated the response of non-motor symptoms to dopaminergic therapy. In the domain of neuropsychiatric disturbances, there is increasing evidence that dopamine agonists can ameliorate depression or anxiety. Other neuropsychiatric symptoms such as psychosis or impulse control disorders can also be worsened or even be induced by dopaminergic agents. For the treatment of sleep disturbances, it is essential to identify different subtypes of sleep pathologies. While there is for example profound evidence for the effectiveness of dopaminergic medication for the treatment of restless legs syndrome and sleep fragmentation, evidence for an improvement of rapid eye movement sleep behavior disorder is lacking. With regard to the broad spectrum of autonomic disturbances, response to dopaminergic treatment seems to differ largely, with on the one hand, some evidence for an improvement of sexual function or sweating with dopaminergic treatment, while on the other hand, constipation can be worsened. Finally, the analysis of sensory deficits reveals that some forms of pain, in particular fluctuation-dependent dystonic pain, can be well addressed by adapting the dopaminergic therapy, while no effect has been seen so far for hyposmia or visual deficits. Moreover, the occurrence of non-motor fluctuations is gaining increased attention, as they can be specifically addressed by a more continuous dopaminergic intake. Taken together, there is evidence of a good response of some (but not all) non-motor symptoms to dopaminergic therapy, which must be individually adapted to the special spectrum of symptoms.

Nonmotor Effects of Conventional and Transdermal Dopaminergic Therapies in Parkinson's Disease

Nonmotor symptoms (NMS) are an integral component of Parkinson's disease (PD). Because the burden and range of NMS are key determinants of quality of life for patients and caregivers, their management is a crucial issue in clinical practice. Although a range of NMS have a dopaminergic pathophysiological basis, this fact is underrecognized, and thus, they are often regarded as dopamine unresponsive symptoms. However, substantial evidence indicates that many NMS respond to oral and transdermal dopaminergic therapies. In contrast, certain NMS are exacerbated or even precipitated by dopaminergic drugs and these unwanted effects may be seriously dangerous. Therefore, a dopaminergic strategy for NMS should be based on a consideration of the benefits vs the risks in individual patients with PD.