Effect of Rapid Eye Movement Sleep Behavior Disorder on Obstructive Sleep Apnea Severity and Cognition of Parkinson＇s Disease Patients

Background：Rapid eye movement （REM） sleep behavior disorder （RBD） and obstructive sleep apnea （OSA） are the most common sleep disorders in Parkinson’s disease （PD）. The aim of this study was to identify whether RBD could alleviate OSA severity in PD patients and its effect on cognitive impairment.Methods：From February 2014 to May 2017, we recruited 174 PD patients from the Second Affiliated Hospital of Soochow University, all of whom underwent polysomnography （PSG）. We collected clinical data, PSG results, and compared information between patients with and without RBD or OSA by analysis of covariance. We also investigated the effect of these sleep disorders on cognitive impairment using linear regression.Results：We grouped participants as follows： PD only （n = 53）, PD ＋ OSA （n = 29）, PD ＋ RBD （n = 61）, and PD ＋ RBD ＋ OSA （n = 31）. Minimum oxygen saturation （SaO2） during whole sleep and in REM sleep was higher in PD ＋ RBD ＋ OSA patients than that in PD ＋ OSA patients. PD ＋ RBD patients had worse Mini-Mental Status Examination and Montreal Cognitive Assessment （MoCA） scores than those in the PD group （P 〈 0.001）, especially in visuospatial/executive, attention, and memory functions. The PD ＋ OSA group performed worse than the PD group in the delayed recall domain. After adjusting for age, sex, body mass index, education, disease severity, and other sleep disorders, MoCA was negatively associated with OSA （β = ？0.736, P = 0.043） and RBD （β = ？2.575, P 〈 0.001）. The severity of RBD （tonic/phasic electromyography activity） and OSA （apnea-hypopnea index/oxygen desaturation index/minimum SaO2） were also associated with MoCA. The adjusted β values of RBD-related parameters were higher than that for OSA.Conclusions：We found that RBD alleviated OSA severity; however, RBD and OSA together exacerbated PD cognitive impairment. Further studies are needed to evaluate whether OSA treatment can improve cognition in PD.

Tonic Electromyogram Density in Multiple System Atrophy with Predominant Parkinsonism and Parkinson＇s Disease

Background： Both Parkinson＇s disease （PD） and multiple system atrophy （MSA） have associated sleep disorders related to the underlying neurodegenerative pathology. Clinically, MSA with predominant parkinsonism （MSA-P） resembles PD in the manifestation of prominent parkinsonism, Whether the amount of rapid eye movement （REM） sleep without atonia could be a potential marker for differentiating MSA-P from PD has not been thoroughly investigated. This study aimed to examine whether sleep parameters could provide a method for differentiating MSA-P from PD. Methods： This study comprised 24 MSA-P patients and 30 PD patients, and they were of similar age, gender, and REM sleep behavior disorder （RBD） prevalence. All patients underwent clinical evaluation and one night of video-polysomnography recording. The tonic and phasic chin electromyogram （EMG） activity was manually quantified during REM sleep of each patient. We divided both groups in terms of whether they had RBD to make subgroup analysis. Results： No significant difference between MSA-P group and PD group had been tbund in clinical characteristics and sleep architecture. However, MSA-P patients had higher apnea-hypopnea index （AHI; 1.15 [0.00, 8.73]/h vs. 0.00 [0.00, 0.55]/h, P = 0.024） and higher tonic chin EMG density （34.02 [ 18.48, 57.18]% vs. 8.40 [3.11, 13.061%, P 〈 0.001 ） as compared to PD patients. Subgroup analysis found that tonic EMG density in MSA ＋ RBD subgroup was higher than that in PD ＋ RBD subgroup （55.04 [26.81,69.62]% vs. 11.40 [8.51,20.411%, P 〈 0.001 ）. Furthermore, no evidence of any difference in tonic EMG density emerged between PD ＋ RBD and MSA - RBD subgroups （P 〉 0.05）. Both disease duration （P = 0.056） and AHI （P = 0.051） showed no significant differences during subgroup analysis although there was a trend toward longer disease duration in PD ＋ RBD subgroup and higher AHI in MSA - RBD subgroup. Stepwise multiple linear regression analysis identified the presence of MSA-P （[3 0.552, P 〈 0.001 ） and RBD （[3 = 0.433, P 〈 0.001 ） as predictors of higher tonic EMG density. Conclusion： Tonic chin EMG density could be a potential marker for differentiating MSA-P from PD.

Rapid Eye Movement Sleep Behavior Disorder Symptoms Correlate with Domains of Cognitive Impairment in Parkinson＆#39;s Disease

Background： Rapid eye movement （REM） sleep behavior disorder （RBD） may be a risk factor for cognitive impairment in patients with Parkinson＆#39;s disease （PD）.However, little is known regarding the relation between the severity of RBD and the different domains of cognitive impairment.The aim of this study was： （1） to investigate the domains of cognitive impairment in patients with PD and RBD, and （2） to explore risk factors for PD-mild cognitive impairment （PD-MCI） and the relationship between RBD severity and impairment in different cognitive domains in PD.Methods： The participants were grouped as follows： PD without RBD （PD-RBD;n =42）, PD with RBD （PD ＋ RBD;n =32）, idiopathic RBD （iRBD;n =15）, and healthy controls （HCs;n =36）.All participants completed a battery of neuropsychological assessment of attention and working memory, executive function, language, memory, and visuospatial function.The information of basic demographics, diseases and medication history, and motor and nonmotor manifestations was obtained and compared between PD-RBD and PD ＋ RBD groups.Particular attention was paid to the severity of RBD assessed by the RBD Questionnaire-Hong Kong （RBDQ-HK） and the RBD Screening Questionnaire （RBDSQ）, then we further examined associations between the severity of RBD symptoms and cognitive levels via correlation analysis.Results： Compared to PD-RBD subjects, PD ＋ RBD patients were more likely to have olfactory dysfunction and their Epworth Sleepiness Scale scores were higher （P 〈 0.05）.During neuropsychological testing, PD ＋ RBD patients performed worse than PD-RBD patients, including delayed memory function, especially.The MCI rates were 33%, 63%, 33%, and 8% for PD-RBD, PD ＋ RBD, iRBD, and HC groups, respectively.RBD was an important factor for the PD-MCI variance （odds ratio =5.204, P =0.018）.During correlation analysis, higher RBDSQ and RBDQ-HK scores were significantly associated with poorer performance on the Trail Making Test-B （errors） and Auditory Verbal Learning Test （delayed recall） and higher RBD-HK scores were also associated with Rey-Osterrieth complex figure （copy） results.Conclusions： When PD-RBD and PD ＋ RBD patients have equivalent motor symptoms, PD ＋ RBD patients still have more olfactory dysfunction and worse daytime somnolence.RBD is an important risk factor for MCI, including delayed memory.Deficits in executive function, verbal delayed memory, and visuospatial function were consistently associated with more severe RBD symptoms.

Human iPSCs derived astrocytes rescue rotenone-induced mitochondrial dysfunction and dopaminergic neurodegeneration in vitro by donating functional mitochondria

Background Parkinson’s disease(PD)is one of the neurodegeneration diseases characterized by the gradual loss of dopaminergic(DA)neurons in the substantia nigra region of the brain.Substantial evidence indicates that at the cellular level mitochondrial dysfunction is a key factor leading to pathological features such as neuronal death and accumulation of misfoldedα-synuclein aggregations.Autologous transplantation of healthy purified mitochondria has shown to attenuate phenotypes in vitro and in vivo models of PD.However,there are significant technical difficulties in obtaining large amounts of purified mitochondria with normal function.In addition,the half-life of mitochondria varies between days to a few weeks.Thus,identifying a continuous source of healthy mitochondria via intercellular mitochondrial transfer is an attractive option for therapeutic purposes.In this study,we asked whether iPSCs derived astrocytes can serve as a donor to provide functional mitochondria and rescue injured DA neurons after rotenone exposure in an in vitro model of PD.Methods We generated DA neurons and astrocytes from human iPSCs and hESCs.We established an astroglial-neuronal co-culture system to investigate the intercellular mitochondrial transfer,as well as the neuroprotective effect of mitochondrial transfer.We employed immunocytochemistry and FACS analysis to track mitochondria.Results We showed evidence that iPSCs-derived astrocytes or astrocytic conditioned media(ACM)can rescue DA neurons degeneration via intercellular mitochondrial transfer in a rotenone induced in vitro PD model.Specifically,we showed that iPSCs-derived astrocytes from health spontaneously release functional mitochondria into the media.Mito-Tracker Green tagged astrocytic mitochondria were detected in the ACM and were shown to be internalized by the injured neurons via a phospho-p38 depended pathway.Transferred mitochondria were able to significantly reverse DA neurodegeneration and axonal pruning following exposure to rotenone.When rotenone injured neurons were cultured in presence of ACM depleted of mitochondria(by ultrafiltration),the neuroprotective effects were abolished.Conclusions Our studies provide the proof of principle that iPSCs-derived astrocytes can act as mitochondria donor to the injured DA neurons and attenuate pathology.Using iPSCs derived astrocytes as a donor can provide a novel strategy that can be further developed for cellular therapy for PD.

Sonographic Alteration of Basal Ganglia in Different Forms of Primary Focal Dystonia： A Cross-sectional Study

Background：Few studies have addressed whether abnormalities in the lenticular nucleus （LN） are characteristic transcranial sonography （TCS） echo features in patients with primary dystonia.This study aimed to explore alterations in the basal ganglia in different forms of primary focal dystonia.Methods：A cross-sectional observational study was performed between December 2013 and December 20 1 4 in 80 patients with different forms of primary focal dystonia and 55 neurologically normal control subjects.TCS was performed in patients and control subjects.Multiple comparisons of multiple rates were used to compare LN hyperechogenicity ratios between control and patient groups.Results：Thirteen individuals were excluded due to poor temporal bone windows,and two subjects were excluded due to disagreement in evaluation by sonologists.Totally,70 patients （cervical dystonia,n =30;blepharospasm,n =30;oromandibular dystonia,n =10） and 50 normal controls were included in the final analysis.LN hyperechogenicity was observed in 51% （36/70） of patients with primary focal dystonia,compared with 12% （6/50） of controls （P 〈 0.001）.Substantia nigra hyperechogenicity did not differ between the two groups.LN hyperechogenicity was observed in 73% （22/30） of patients with cervical dystonia,a greater prevalence than in patients withblepharospasm （33%,10/30,P =0.002） and oromandibular dystonia （40%,4/10,P =0.126）.LN hyperechogenicity was more frequently observed in patients with cervical dystonia compared with controls （73% vs.12%,P 〈 0.001）;however,no significant difference was detected in patients with blepharospasm （33% vs.12%,P =0.021） or oromandibular dystonia （40% vs.12%,P =0.088）.Conclusions：LN hyperechogenicity is more frequently observed in patients with primary focal dystonia than in controls.It does not appear to be a characteristic TCS echo feature in patients with blepharospasm or oromandibular dystonia.

Long-term Levodopa Treatment Accelerates the Circadian Rhythm Dysfunction in a 6-hydroxydopamine Rat Model of Parkinson＇s Disease

Background： Parkinson＇s disease （PD） patients with long-term levodopa （L-DOPA） treatment are suffering from severe circadian dysfunction. However, it is hard to distinguish that the circadian disturbance in patients is due to the disease progression itself, or is affected by L-DOPA replacement therapy. This study was to investigate the role of L-DOPA on the circadian dysfunction in a rat model of PD. Methods： The rat model of PD was constructed by a bilateral striatal injection with 6-hydroxydopamine （6-OHDA）, followed by administration of saline or 25 mg/kg L-DOPA for 21 consecutive days. Rotarod test, footprint test, and open-field test were carried out to evaluate the motor function. Striatum, suprachiasmatic nucleus （SCN）, liver, and plasma were collected at 6：00, 12：00, 18：00, and 24：00. Quantitative real-time polymerase chain reaction was used to examine the expression of clock genes. Enzyme-linked immunosorbent assay was used to determine the secretion level of cortisol and melatonin. High-performance liquid chromatography was used to measure the neurotransmitters. Analysis of variance was used for data analysis. Results： L-DOPA alleviated the motor deficits induced by 6-OHDA lesions in the footprint and open-field test （P 〈 0.01, P 〈 0.001, respectively）. After L-DOPA treatment, Bmall decreased in the SCN compared with 6-OHDA group at 12：00 （P 〈 0.01） and 24：00 （P 〈 0.001 ）. In the striatum, the expression ofBmall, Rorα was lower than that in the 6-OHDA group at 18：00 （P 〈 0.05） and L-DOPA seemed to delay the peak of Per2 to 24：00. In liver, L-DOPA did not affect the rhythmicity and expression of these clock genes （P 〉 0.05）. In addition, the cortisol secretion was increased （P 〉 0.05）, but melatonin was further inhibited after L-DOPA treatment at 6：00 （P 〈 0.01）. Conclusions： In the circadian system of advanced PD rat models, circadian dysfunction is not only contributed by the degeneration of the disease itself but also long-term L-DOPA therapy may further aggravate it.

Fatigue correlates with sleep disturbances in Parkinson disease

Background: Many Parkinson disease (PD) patients complain about chronic fatigue and sleep disturbances during the night. The objective of this study is to determine the relationship between fatigue and sleep disturbances by using polysomnography (PSG) in PD patients.Methods: Two hundred and thirty-two PD patients (152 with mild fatigue and 80 with severe fatigue) were recruited in this study. Demographic information and clinical symptoms were collected. Fatigue severity scale (FSS) was applied to evaluate the severity of fatigue, and PSG was conducted in all PD patients. FSS ≥4 was defined as severe fatigue, and FSS <4 was defined as mild fatigue. Multivariate logistic regression and linear regression models were used to investigate the associations between fatigue and sleep disturbances.Results: Patients with severe fatigue tended to have a longer duration of disease, higher Unified Parkinson Disease Rating Scale score, more advanced Hoehn and Yahr stage, higher daily levodopa equivalent dose, worse depression, anxiety, and higher daytime sleepiness score. In addition, they had lower percentage of rapid eye movement (REM) sleep (P = 0.009) and were more likely to have REM sleep behavior disorder (RBD) (P = 0.018). Multivariate logistic regression analyses found that the presence of RBD and proportion of REM sleep were the independent predictors for fatigue. After the adjustment of age, sex, duration, body mass index, severity of disease, scores of Hamilton Rating Scale for Depression, Hamilton Anxiety Rating Scale, and other sleep disorders, proportion of REM sleep and degree of REM sleep without atonia in patients with PD were still associated with FSS score.Conclusion: Considering the association between fatigue, RBD, and the altered sleep architecture, fatigue is a special subtype in PD and more studies should be focused on this debilitating symptom.

Substantia nigra hyperechogenicity in Parkinson disease patients with leucine-rich repeat kinase 2 variants in the Chinese Han population

To the Editor:Parkinson disease(PD)is the second most common neurodegenerative disease,and is characterized by both motor and non-motor symptoms.The leucine-rich repeat kinase 2(LRRK2)gene,characterized by different mutations among different populations,is well-known in both familial and sporadic PD.The frequency of theG2019S mutation is 20%to 40%in the Ashkenazi Jewish and North African Arab populations,while G2385R is a common risk factor associated with Asian populations.Research teams have found that G2385R is also associated with PD in the Chinese Han population,suggesting a clear contribution of this mutation to the Han population,but descriptions of clinical PD symptoms in the Chinese Han population are rare and warrant further G2385R genotype-phenotype analyses.