Bidirectional Relationship Between Sleep Disturbances and Parkinson's Disease

Correlation of slow-wave sleep with motor and nonmotor progression in Parkinson's disease

OBJECTIVE

This study aimed to explore the association between slow-wave sleep and the progression of motor and nonmotor symptoms in patients with PD.

METHODS

Data were collected from the Parkinson's Progression Markers Initiative study. Slow-wave sleep, also known as deep non-rapid eye movement (DNREM) sleep, was objectively assessed using the Verily Study Watch. Motor function was assessed using the Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III score, Hoehn and Yahr stage, freezing of gait, motor fluctuations, and dyskinesia severity. Comprehensive assessments were conducted on nonmotor symptoms, including depression, anxiety, global cognitive function, and autonomic dysfunction. Statistical analyses involved repeated-measures analysis of variance and linear regression.

RESULTS

A total of 102 patients with PD were included in the study, with a median follow-up duration of 3.4 years. In the long DNREM sleep duration group (n = 55), better motor function (DNREM × time interaction: F(1,100) = 4.866, p = 0.030), less severe sexual dysfunction (p = 0.026), and improved activities of daily living (p = 0.033) were observed at the last follow-up visit compared with the short DNREM sleep duration group (n = 47). Reduced DNREM sleep duration is a risk factor for motor progression (β = -0.251, p = 0.021; 95% confidence interval = -0.465 to -0.038).

INTERPRETATION

The findings suggest an association between longer DNREM sleep duration and slower motor and nonmotor progression in patients with PD.

Fighting Against the Clock: Circadian Disruption and Parkinson's Disease

Circadian disruption is being increasingly recognized as a critical factor in the development and progression of Parkinson's disease (PD). This review aims to provide an in-depth overview of the relationship between circadian disruption and PD by exploring the molecular, cellular, and behavioral aspects of this interaction. This review will include a comprehensive understanding of how the clock gene system and transcription-translation feedback loops function and how they are diminished in PD. The article also discusses the role of clock genes in the regulation of circadian rhythms, as well as the impact of clock gene dysregulation on mitochondrial function, oxidative stress, and neuroinflammation, including the microbiota-gut-brain axis, which have all been proposed as being crucial mechanisms in the pathophysiology of PD. Finally, this review highlights potential therapeutic strategies targeting the clock gene system and circadian rhythm for the treatment of PD.

Cognitive impairment and dementia in young onset Parkinson's disease

BACKGROUND AND OBJECTIVE

Patients with young-onset Parkinson's disease (YOPD) have a slower progression. Our aim was to analyze the change in cognitive function in YOPD compared to patients with a later onset and controls.

PATIENTS AND METHODS

Patients with Parkinson's disease (PD) and controls from the COPPADIS cohort were included. Cognitive function was assessed with the Parkinson's Disease Cognitive Rating Scale (PD-CRS) at baseline (V0), 2-year ± 1 month (V2y), and 4-year ± 3 months follow-up (V4y). Regarding age from symptoms onset, patients were classified as YOPD (< 50 years) or non-YOPD (≥ 50). A score in the PD-CRS < 81 was defined as cognitive impairment (CI): ≤ 64 dementia; 65-80 mild cognitive impairment (MCI).

RESULTS

One-hundred and twenty-four YOPD (50.7 ± 7.9 years; 66.1% males), 234 non-YOPD (67.8 ± 7.8 years; 59.3% males) patients, and 205 controls (61 ± 8.3 years; 49.5% males) were included. The score on the PD-CRS and its subscore domains was higher at all visits in YOPD compared to non-YOPD patients and to controls (p < 0.0001 in all analysis), but no differences were detected between YOPD patients and controls. Only non-YOPD patients had significant impairment in their cognitive function from V0 to V4y (p < 0.0001). At V4y, the frequency of dementia and MCI was 5% and 10% in YOPD compared to 25.2% and 22.3% in non-YOPD patients (p < 0.0001). A lower score on the Parkinson's Disease Sleep Scale at baseline was a predictor of CI at V4y in YOPD patients (Adjusted R2 = 0.61; OR = 0.965; p = 0.029).

CONCLUSION

Cognitive dysfunction progressed more slowly in YOPD than in non-YOPD patients.

How sleep quality affects activities of daily living in Parkinson's disease: the mediating role of disease severity and the moderating role of cognition

Objective

The aim of this study was to explore the influential mechanism of the relationship between sleep quality and activities of daily living (ADL) in patients with Parkinson's disease (PD), we hypothesized disease severity as a mediator and assumed the mediating process was regulated by cognition.

Methods

194 individuals with PD (95 women and 99 men) were enrolled in study. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality of PD patients. Patients' ADL, disease severity and cognition were measured by the Unified Parkinson's Disease Rating Scale-II (UPDRSII), Hoehn-Yahr (H-Y) Scale, and Mini-Mental State Examination (MMSE). We investigated the mediating role of disease severity and the moderating effect of cognition on the association between sleep quality and ADL in PD patients.

Results

The score of UPDRSII was positively correlated with the score of PSQI and H-Y stage, while the score of MMSE was negatively correlated with the score of H-Y stage and UPDRSII. Sleep quality predicts disease severity, and disease severity predicts ADL. Disease severity mediated the relationship between sleep quality and ADL, and the mediating effect was 0.179. Cognition alone did not affect ADL, but the interaction between disease severity and cognition was significantly affected ADL, confirming the moderating effect of cognition in PD patients.

Conclusion

Disease severity mediated the association between sleep quality and ADL, good cognition significantly reduced disease severity's mediating influence on the relationship between sleep quality and ADL. Our study indicated a close relationship between ADL and sleep and cognition in PD, and also provided new insights into the overall management of PD and a better quality of life of PD patients.

Pharmacological interventions targeting α-synuclein aggregation triggered REM sleep behavior disorder and early development of Parkinson's disease

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by elevated motor behaviors and dream enactments in REM sleep, often preceding the diagnosis of Parkinson's disease (PD). As RBD could serve as a biomarker for early PD developments, pharmacological interventions targeting α-synuclein aggregation triggered RBD could be applied toward early PD progression. However, robust therapeutic guidelines toward PD-induced RBD are lacking, owing in part to a historical paucity of effective treatments and trials. We reviewed the bidirectional links between α-synuclein neurodegeneration, progressive sleep disorders, and RBD. We highlighted the correlation between RBD development, α-synuclein aggregation, and neuronal apoptosis in key brainstem regions involved in REM sleep atonia maintenance. The current pharmacological intervention strategies targeting RBD and their effects on progressive PD are discussed, as well as current treatments for progressive neurodegeneration and their effects on RBD. We also evaluated emerging and potential pharmacological solutions to sleep disorders and developing synucleinopathies. This review provides insights into the mechanisms and therapeutic targets underlying RBD and PD, and explores bidirectional treatment effects for both diseases, underscoring the need for further research in this area.

Sleep-Disturbance-Induced Microglial Activation Involves CRH-Mediated Galectin 3 and Autophagy Dysregulation

Chronic sleep disturbances (CSDs) including insomnia, insufficient sleep time, and poor sleep quality are major public health concerns around the world, especially in developed countries. CSDs are major health risk factors linked to multiple neurodegenerative and neuropsychological diseases. It has been suggested that CSDs could activate microglia (Mg) leading to increased neuroinflammation levels, which ultimately lead to neuronal dysfunction. However, the detailed mechanisms underlying CSD-mediated microglial activation remain mostly unexplored. In this study, we used mice with three-weeks of sleep fragmentation (SF) to explore the underlying pathways responsible for Mg activation. Our results revealed that SF activates Mg in the hippocampus (HP) but not in the striatum and prefrontal cortex (PFc). SF increased the levels of corticotropin-releasing hormone (CRH) in the HP. In vitro mechanism studies revealed that CRH activation of Mg involves galectin 3 (Gal3) upregulation and autophagy dysregulation. CRH could disrupt lysosome membrane integrity resulting in lysosomal cathepsins leakage. CRHR2 blockage mitigated CRH-mediated effects on microglia in vitro. SF mice also show increased Gal3 levels and autophagy dysregulation in the HP compared to controls. Taken together, our results show that SF-mediated hippocampal Mg activation involves CRH mediated galectin 3 and autophagy dysregulation. These findings suggest that targeting the hippocampal CRH system might be a novel therapeutic approach to ameliorate CSD-mediated neuroinflammation and neurodegenerative diseases.