Evaluation of autonomic functions of patients with multiple system atrophy and Parkinson's disease by head-up tilt test

Renalase Overexpression-Mediated Excessive Metabolism of Peripheral Dopamine, DOPAL Accumulation, and α-Synuclein Aggregation in Baroreflex Afferents Contribute to Neuronal Degeneration and Autonomic Dysfunction

Background/Objectives: Increasing evidence reveals the likely peripheral etiology of Parkinson's disease; however, the mechanistic insight into α-Synuclein aggregation in the periphery remains unclear. This study aimed to explore the effect of abnormal expression of renalase on dopamine metabolism, toxic DOPAL generation, and subsequently, α-Synuclein aggregation. Methods: Blood pressure (BP) was monitored while changing the body position of rats; the serum level of renalase was detected by ELISA; the mRNA/protein of renalase and α-Synuclein were determined by qRT-PCR/Western blot; DOPAL was measured using HPLC; renalase distribution was explored by immunostaining; cell viability and ultrastructure were examined by TUNEL and electron microscopy, respectively. Results: The results showed that, in PD model rats, the serum level of renalase was increased time-dependently with up-regulated renalase gene/protein expression in the nodose ganglia, nucleus tractus solitarius, and heart; a reduced dopamine content was also detected by the renalase overexpression in PC12 cells. Strikingly, up-regulated renalase and orthostatic BP changes were observed before the behavioral changes in the model rats. Meanwhile, the levels of DOPAL and α-Synuclein were increased time-dependently. Intriguingly, the low molecular weight of α-Synuclein declined coordinately with the increase in the higher molecular weight of α-Synuclein. Clear ultrastructure damage at the cellular level supported the notion of molecular findings. Notably, the α-Synuclein aggregation-induced impairment of the axonal transport function predates neuronal degeneration mediated by renalase overexpression. Conclusions: Our results demonstrate that abnormal peripheral dopamine metabolism mediated by overexpressed renalase promotes the DOPAL-induced α-Synuclein and leads to baroreflex afferent neuronal degeneration and early autonomic failure.

The differences of orthostatic hypotension in patients with Parkinson's disease and multiple system atrophy

Background

Multiple system atrophy (MSA) and Parkinson's disease (PD) have similar clinical presentations in their early stages. Orthostatic hypotension (OH) is a common autonomic dysfunction associated with MSA and PD. Heart rate (HR) and systolic blood pressure (SBP) changes are measured in response to the active standing test, which is widely used to screen for cardiovascular autonomic function.

Objectives and methods

Overall, 255 patients (67 MSA, 188 PD) underwent continuous beat-to-beat non-invasive BP monitoring and active standing test. The total standing time was 10 min, and the BP differences between both groups were compared to determine whether the ΔHR/ΔSBP can differentiate both conditions.

Results

Classical orthostatic hypotension (COH) (52%) and initial OH (19%) were most common in MSA and PD, respectively. MSA had a higher HR (75.0 ± 9.7 vs. 71.0 ± 10.7, P = 0.008) than PD in the supine position. SBP (135.70 ± 15.68 mmHg vs. 127.31 ± 15.14 mmHg, P = 0.106), diastolic BP (78.45 ± 12.36 mmHg vs. 67.15 ± 13.39 mmHg, P = 0.009) and HR (73.94 ± 8.39 bpm vs. 71.08 ± 13.52 bpm, P = 0.389) at baseline were higher in MSA-COH than in PD-COH. After adjusting for age and disease duration, the ΔHR/ΔSBP-10 min significantly discriminated MSA-COH from PD-COH (P = 0.031). An ΔHR/ΔSBP-10 min of 0.517 showed a sensitivity of 67% and specificity of 84% (AUC = 0.77, 95% CI: 0.63-0.91).

Conclusion

The SBP, diastolic BP, and HR were higher in the supine position; however, ΔHR and ΔSBP were lower after standing in MSA patients than in PD patients. The ΔHR/ΔSBP-10 min discriminated between MSA-COH and PD-COH with quiet acceptable accuracy.

Vagal cross-sectional area correlates with parasympathetic dysfunction in Parkinson's disease

The aim of this prospective study was to investigate autonomic function in Parkinson's disease with a multidimensional approach including clinical evaluation tools, head-up tilt test and morphological studies of the vagus nerve. Head-up tilt test parameters including high frequency power of the heart frequency interval, the ratio of low frequency power of the distance between two consecutive R waves in electrocardiogram (RR interval) to the high frequency and low frequency power of systolic blood pressure were used to evaluate parasympathetic, cardiac sympathetic and vasomotor sympathetic functions, respectively, in 80 patients with Parkinson's disease. We examined the cross-sectional area of the vagus nerves bilaterally using nerve ultrasound and compared mean values with a control group of healthy subjects (n = 40) as well as patients with chronic inflammatory demyelinating polyneuropathy (n = 76). The cross-sectional area of right/left vagus nerve of Parkinson's patients was significantly lower compared to the right/left vagus nerve of the control group and of chronic demyelinating polyneuropathy patients. Furthermore, the cross-sectional area of the right vagus nerve was significantly larger from the one of the left vagus nerve for all groups. Based on tilt test, 43 patients (disease duration 7 ± 5, age at evaluation 71 ± 9, Hoehn and Yahr score 2.8 ± 8) were diagnosed with autonomic dysfunction (orthostatic hypertension n = 11, chronotropic incompetence n = 31, postural orthostatic tachycardia syndrome n = 1). Patients with orthostatic hypotension showed significantly higher Unified Parkinson's Disease Rating Scale-III values than those with chronotropic incompetence. The cross-sectional area of the vagus nerve correlated inversely with heart rate in rest and supine position and positively with tilt test parameters representing parasympathetic modulation through vagal activity [high frequency power of the distance between two consecutive R waves in electrocardiogram (RR interval)] at rest. We demonstrate for the first time that morphological characteristics of the vagus nerve correlate with parameters of parasympathetic function from the spectral analysis of cardiovascular parameters in tilt test for Parkinson's patients. This correlation reveals the impact of the atrophy of vagal atrophy for autonomic function in Parkinson's disease. Nerve ultrasound of the vagus nerve could potentially be used as an adjunct to tilt table examination to diagnose autonomic dysfunction.

Crossover trial of the effects of a far-infrared heater that heats the feet with ceramic balls on autonomic nervous activity and mood states

INTRODUCTION

The accumulation of fatigue and stress creates problems, including reductions in quality of life and productivity.

OBJECTIVES

To investigate the effects of a far-infrared heater that heats the feet with ceramic balls on autonomic nervous activity and mood states.

METHODS

This study was performed as a crossover trial. Participants comprised 20 women. On different days, each participant underwent 15 min of foot warming with the far-infrared heater (far-infrared group) or remained seated for 15 min (control group). Autonomic nervous activity (low-frequency component/high-frequency component, high-frequency) and mood states scales (Profile of Mood States Second Edition and Two-Dimensional Mood Scale for Self-monitoring and Self-regulation of Momentary Mood States) during the study intervention were measured and compared between groups.

RESULTS

Low-frequency/high-frequency was significantly higher in the control group 10 min after the start of intervention than at baseline (P = .033). Low-frequency/high-frequency was significantly lower in the far-infrared group than in the control group at 5 min (P = .027), 10 min (P = .011), and 15 min (P = .015). High-frequency was significantly higher in the far-infrared group at 5 min (P = .008), 10 min (P = .004), and 15 min (P = .015) than at baseline. High-frequency 5 min after the start of intervention was significantly higher in the far-infrared group than in the control group (P = .033). POMS2 scores improved significantly more in the far-infrared group than in the control group, including in fatigue-inertia (P = .019), tension-anxiety (P = .025), and total mood disturbance (P = .019). Finally, the far-infrared group showed greater improvements in Two-Dimensional Mood Scale-Short Term scores such as stability (P = .002) and pleasure (P = .013).

CONCLUSION

Using the far-infrared heater to heat the feet with ceramic balls stabilized and improved mood, reduced Fatigue-Inertia and Tension-Anxiety, and alleviated total mood disturbance. Parasympathetic nervous system activation was observed from 5 min after the start of heating, suggesting that short-duration heat stimulation of the feet is effective.

Autonomic and cardiorespiratory responses to the active tilt test in individuals with Parkinson disease: cross-sectional study

BACKGROUND

The Parkinson disease (PD) is frequently associated with autonomic dysfunctions. However, data regarding the influence of PD on the autonomic responses to postural changes is limited.

OBJECTIVE

To analyze and compare the autonomic responses, evaluated through linear and non-linear methods of heart rate variability, and cardiorespiratory parameters in two groups: Parkinson disease (PDG) and control (CG), at rest and during the active tilt test.

METHODS

A total of 48 participants were analyzed (PDG: n = 25;73.40 ± 7.01 years / CG: n = 23;70.17 ± 8.20 years). The autonomic modulation and cardiorespiratory parameters were evaluated at rest and during the active tilt test. To assess the autonomic modulation the linear indices, at the time (rMSSD, SDNN) and frequency (LF, HF, LF/HF) domains, and the non-linear indices, obtained through the Poincaré plot (SD1, SD2, SD1/SD2), were calculated. The cardiorespiratory parameters evaluated were heart rate (HR), systolic (SBP), and diastolic blood pressure (DBP), peripheral oxygen saturation (SpO₂), and respiratory rate.

RESULTS

At rest, the PDG presented significantly lower values of rMSSD, SDNN, LF, HF, SD1, SD2, and DBP, and higher values of SpO₂. During test, in the PD group, modifications were observed in HR, and SBP, besides a reduced parasympathetic response, and an increased global modulation. The qualitative analysis of the Poincaré plot showed that the PDG has a lower dispersion of the RR intervals during rest and the active tilt test.

CONCLUSION

Individuals with PD present reduced global variability and parasympathetic modulation at rest, and reduced parasympathetic response and damage in HR regulation when performing the active tilt test, compared with controls.

Effect of cold oral stimulation on orthostatic hypotension in multiple system atrophy: a case study

[Purpose] The aim of this case study is to reconsider the method for preventing orthostatic hypotension in multiple system atrophy. [Participant and Methods] The case was that of a 70-year-old female with multiple system atrophy who experienced frequent falls and orthostatic hypotension. An orthostatic test was performed, and the effect of cold oral stimulation before standing was compared with no stimulation. Outcome measures were blood pressure, heart rate variability and autonomic variables. [Results] In the control test, blood pressure decreased from 150/72 mmHg in the supine position to 98/58 mmHg in the standing position. Heart rate increased from 71 bpm to 82 bpm, high frequency declined from 16.48 msec² to 14.07 msec², and low/high frequency increased from 2.56 to 5.13. Cold stimulation in the standing position induced changes in blood pressure from 168/82 mmHg to 104/72 mmHg, heart rate from 73 bpm to 83 bpm, high frequency from 61.29 msec² to 24.56 msec², and low/high frequency from 1.45 to 6.33 msec². [Conclusion] Standing after cold stimulation affected autonomic variables, but did not affect the heart rate or blood pressure, possibly because of damaged peripheral blood vessels. Further research is required to demonstrate the effect of cold stimulation on orthostatic hypotension.