Effects of sleep fragmentation on white matter pathology in a rat model of cerebral small vessel disease

STUDY OBJECTIVES

Mounting evidence indicated the correlation between sleep and cerebral small vessel disease (CSVD). However, little is known about the exact causality between poor sleep and white matter injury, a typical signature of CSVD, as well as the underlying mechanisms.

METHODS

Spontaneously hypertensive rats (SHR) and control Wistar Kyoto rats were subjected to sleep fragmentation (SF) for 16 weeks. The effects of chronic sleep disruption on the deep white matter and cognitive performance were observed.

RESULTS

SHR were validated as a rat model for CSVD. Fragmented sleep induced strain-dependent white matter abnormalities, characterized by reduced myelin integrity, impaired oligodendrocytes precursor cells (OPC) maturation and pro-inflammatory microglial polarization. Partially reversible phenotypes of OPC and microglia were observed in parallel following sleep recovery.

CONCLUSIONS

Long-term SF-induced pathological effects on the deep white matter in a rat model of CSVD. The pro-inflammatory microglial activation and the block of OPC maturation may be involved in the mechanisms linking sleep to white matter injury.

Slow-wave sleep and REM sleep without atonia predict motor progression in Parkinson's disease

BACKGROUND

Growing evidence supports the potential role of sleep in the motor progression of Parkinson's disease (PD). Slow-wave sleep (SWS) and rapid eye movement (REM) sleep without atonia (RWA) are important sleep parameters. The association between SWS and RWA with PD motor progression and their predictive value have not yet been elucidated.

METHODS

We retro-prospectively analyzed clinical and polysomnographic data of 136 patients with PD. The motor symptoms were assessed using Unified Parkinson's Disease Rating Scale Part III (UPDRS III) at baseline and follow-up to determine its progression. Partial correlation analysis was used to explore the cross-sectional associations between slow-wave energy (SWE), RWA and clinical symptoms. Longitudinal analyses were performed using Cox regression and linear mixed-effects models.

RESULTS

Among 136 PD participants, cross-sectional partial correlation analysis showed SWE decreased with the prolongation of the disease course (P = 0.046), RWA density was positively correlated with Hoehn & Yahr (H-Y) stage (tonic RWA, P < 0.001; phasic RWA, P = 0.002). Cox regression analysis confirmed that low SWE (HR = 1.739, 95% CI = 1.038-2.914; P = 0.036; FDR-P = 0.036) and high tonic RWA (HR = 0.575, 95% CI = 0.343-0.963; P = 0.032; FDR-P = 0.036) were predictors of motor symptom progression. Furthermore, we found that lower SWE predicted faster rate of axial motor progression (P < 0.001; FDR-P < 0.001) while higher tonic RWA density was associated with faster rate of rigidity progression (P = 0.006; FDR-P = 0.024) using linear mixed-effects models.

CONCLUSIONS

These findings suggest that SWS and RWA might represent markers of different motor subtypes progression in PD.

The association between plasma GPNMB and Parkinson's disease and multiple system atrophy

AIMS

Parkinson's disease (PD), as the second most common neurodegenerative disorder, often presents diagnostic challenges in differentiation from other forms of Parkinsonism. Recent studies have reported an association between plasma glycoprotein nonmetastatic melanoma protein B (pGPNMB) and PD.

METHODS

A retrospective study was conducted, comprising 401 PD patients, 111 multiple system atrophy (MSA) patients, 13 progressive supranuclear palsy (PSP) patients and 461 healthy controls from the Chinese Han population, with an assessment of pGPNMB levels.

RESULTS

The study revealed that pGPNMB concentrations were significantly lower in PD and MSA patients compared to controls (area under the receiver operating characteristics curve (AUC) 0.62 and 0.74, respectively, P < 0.0001 for both), but no difference was found in PSP patients compared to controls (P > 0.05). Interestingly, the level of pGPNMB was significantly higher in PD patients than in MSA patients (AUC = 0.63, P < 0.0001). Furthermore, the study explored the association between pGPNMB levels and disease severity in PD and MSA patients, revealing a positive correlation in PD patients but not in MSA patients with both disease severity and cognitive impairment.

CONCLUSION

This study successfully replicated prior findings, demonstrating an association between pGPNMB levels and disease severity, and also identified a correlation with cognitive impairment in PD patients of the Chinese Han population. Additionally, this study is the first to identify a significant difference in pGPNMB levels between MSA, PD, and normal controls. The data provide new evidence supporting the potential role of pGPNMB in the diagnosis and differential diagnosis of Parkinsonism.

Safinamide alleviates hyperalgesia via inhibiting hyperexcitability of DRG neurons in a mouse model of Parkinson's disease

Pain is a widespread non-motor symptom that presents significant treatment challenges in patients with Parkinson's disease (PD). Safinamide, a new drug recently introduced for PD treatment, has demonstrated analgesic effects on pain in PD patients, though the underlying mechanisms remain unclear. To investigate the analgesic and anti-PD effect of safinamide, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model was used, and rasagiline as positive control on motor symptoms. Notably, only safinamide alleviated hyperalgesia in MPTP mice. Whole-cell patch-clamp recordings of dorsal root ganglion (DRG) neurons revealed hyperexcitability in MPTP mice, which safinamide counteracted in a concentration-dependent manner. The voltage clamp further demonstrated that sodium current in DRG neurons of MPTP mice was enhanced and safinamide reduced sodium current density. RT-qPCR identified upregulated Nav1.7 and Nav1.8 transcripts (Scn9a and Scn10a) in DRG neurons of MPTP mice. Our results suggest that safinamide could relieve hyperalgesia by inhibiting DRG neuron hyperexcitability in MPTP mice.

PACAP/PAC1-R activation contributes to hyperalgesia in 6-OHDA-induced Parkinson's disease model rats via promoting excitatory synaptic transmission of spinal dorsal horn neurons

Pain is a common annoying non-motor symptom in Parkinson's disease (PD) that causes distress to patients. Treatment for PD pain remains a big challenge, as its underlying mechanisms are elusive. Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor PAC1-R play important roles in regulating a variety of pathophysiological processes. In this study, we investigated whether PACAP/PAC1-R signaling was involved in the mechanisms of PD pain. 6-hydroxydopamine (6-OHDA)-induced PD model was established in rats. Behavioral tests, electrophysiological and Western blotting analysis were conducted 3 weeks later. We found that 6-OHDA rats had significantly lower mechanical paw withdrawal 50% threshold in von Frey filament test and shorter tail flick latency, while mRNA levels of Pacap and Adcyap1r1 (gene encoding PAC1-R) in the spinal dorsal horn were significantly upregulated. Whole-cell recordings from coronal spinal cord slices at L4-L6 revealed that the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) in dorsal horn neurons was significantly increased, which was reversed by application of a PAC1-R antagonist PACAP 6-38 (250 nM). Furthermore, we demonstrated that intrathecal microinjection of PACAP 6-38 (0.125, 0.5, 2 μg) dose-dependently ameliorated the mechanical and thermal hyperalgesia in 6-OHDA rats. Inhibition of PACAP/PAC1-R signaling significantly suppressed the activation of Ca2+/calmodulin-dependent protein kinase II and extracellular signal-regulated kinase (ERK) in spinal dorsal horn of 6-OHDA rats. Microinjection of pAAV-Adcyap1r1 into L4-L6 spinal dorsal horn alleviated hyperalgesia in 6-OHDA rats. Intrathecal microinjection of ERK antagonist PD98059 (10 μg) significantly alleviated hyperalgesia in 6-OHDA rats associated with the inhibition of sEPSCs in dorsal horn neurons. In addition, we found that serum PACAP-38 concentration was significantly increased in PD patients with pain, and positively correlated with numerical rating scale score. In conclusion, activation of PACAP/PAC1-R induces the development of PD pain and targeting PACAP/PAC1-R is an alternative strategy for treating PD pain.

[The correlation between nutritional status, body composition, and symptoms in Parkinson's disease patients]

Objective: To investigate the relationship between nutritional status, body composition and symptoms of Parkinson's disease (PD). Methods: The study was conducted among 102 PD patients between November 2020 to April 2021 in the outpatient and inpatient of Neurology department of the Second Affiliated Hospital of Suzhou University. Basic data, such as age, gender, course of disease and Hoehn-Yahr (H-Y) stage of the patients, were collected. In the "open" state, the Unified Parkinson's Disease Rating Scale (UPDRS) and other scales were used to evaluate the clinical symptoms of PD patients. The nutritional status of PD patients was evaluated by the micro-nutrition rating Scale (MNA), and the body composition data of PD patients was measured by the body composition analyzer.The patients were divided into three groups according to the MNA: well-nourished group(45 cases), malnutrition-risk group (43 cases)and malnutrition group(14 cases). Body composition, laboratory tests, bone density, and symptoms of PD were compared among the three groups. Results: Among 102 PD patients, 48 were males (47.1%) and 54 were females (52.9%), aged 42-86 (66±9) years old. Compared with the malnutrition-risk group, lymphocytes in the malnutrition group [(1.45±0.48) × 109/L vs (1.76±0.43)×109/L], uric acid [(227±54) μmol/L vs (282±63) μmol/L] were all low, and the difference was statistically significant (all P<0.05). Compared with the well-nourished group, hemoglobin [(125±17) g/L vs (136±14) g/L], prealbumin [(0.23±0.05) g/L vs (0.27±0.06) g/L], and uric acid [(227±54) μmol/L vs (312±76) μmol/L] and Retinol binding protein [(33±7) mg/L were lower than (39±10) mg/L] in the malnutrition group, the difference was statistically significant (P<0.05). Except for the visceral fat area and body fat percentages, there was no significant difference in body composition indexes and bone mineral density T-value between the malnutrition-risk and malnutrition groups (P<0.05). Compared with the well-nourished group, the body fat [(16±6) kg vs (20±6) kg], the percentage of body fat [(26±9)% vs (29±7)%], the waist-hip ratio [(0.86±0.05) vs (0.89±0.05)], and the upper arm circumference [(29.00±2.59) cm vs (30.74±2.75) cm] in the malnutrition risk group were lower, and the difference was statistically significant (P<0.05). There were statistically significant differences in all body composition indicators and T-values of bone density between the malnourished and well nourished groups (all P<0.05). The MNA score of PD patients was negatively correlated with UPDRS Ⅰ, UPDRS Ⅱ, and UPDRS Ⅳ scores (r=-0.347, -0.364, -0.303, all P<0.05); Body composition indicators: total body water and inorganic salts were negatively correlated with UPDRS-I (r=-0.206, -0.223, all P<0.05), and body fat was negatively correlated with levodopa Equivalent dose (LED) (r=-0.209, P<0.05) Conclusions: The malnutrition risk and incidence of malnutrition in PD patients are high; lymphocyte, uric acid, hemoglobin, Retinol binding protein, body composition and bone mineral density were low in malnutrition group. MNA score of PD patients was negatively correlated with Parkinson's disease symptoms.

Sarcopenia is associated with non-motor symptoms in Han Chinese patients with Parkinson's Disease: a cross-sectional study

BACKGROUND

Sarcopenia is commonly seen in the older adults and increases in incidence with age, also in Parkinson's disease (PD). Although research has indicated that the development of sarcopenia in patients with PD may be related to both motor symptoms and non-motor symptoms (NMS), the precise relationship between the two conditions remains unclear. Therefore, we aimed to investigate the incidence of sarcopenia in patients with PD and its association with NMS.

METHODS

The study included 123 patients with PD and 38 age- and sex-matched healthy controls (HC). All participants were evaluated for sarcopenia using the 2019 Asian Sarcopenia Diagnostic Criteria, and patients with PD underwent standard assessments of motor symptoms and NMS. Multiple logistic regression and receiver operating characteristic (ROC) curve analyses were used to examine the association between sarcopenia and NMS in patients with PD.

RESULTS

The incidence of sarcopenia was significantly higher in patients with PD than in HC (26.8% vs. 10.4%, p = 0.046). Multiple logistic regression analysis revealed that poorer sleep quality (odds ratio [OR]: 1.245; 95% confidence interval [CI]: 1.011-1.533; p = 0.040) and fatigue (OR: 1.085, 95% CI: 1.006-1.170, p = 0.034) were independently associated with sarcopenia. ROC analysis indicated that the optimal cut-off value for Pittsburgh Sleep Quality Index (PSQI) scores was 10, with 72.7% sensitivity and 74.4% specificity (area under the curve [AUC] = 0.776, 95% CI: 0.683-0.868, p < 0.001). The optimal cut-off value for Fatigue Severity Scale (FSS) scores was 39, with 87% sensitivity and 50% specificity (AUC = 0.725, 95% CI: 0.629 -0.820, p < 0.001). Joint use of FSS and PSQI scores increased the predictive value for sarcopenia(AUC = 0.804, 95% CI: 0.724-0.885, p < 0.001).

CONCLUSION

Patients with PD are more susceptible to sarcopenia than healthy older adults, and fatigue and poorer sleep are positively associated with sarcopenia. Further longitudinal studies are needed to clarify the causal relationships.

A systematic analysis of genotype-phenotype associations with PLA2G6

BACKGROUND

PLA2G6-associated neurodegeneration (PLAN) can be categorized into infantile neuroaxonal dystrophy (INAD), atypical neuroaxonal dystrophy (aNAD), neurodegeneration with brain iron accumulation (NBIA), and early-onset parkinsonism (EOP).

OBJECTIVES

To determine the genotype-phenotype association in PLAN.

METHODS

"PLA2G6" or "PARK14" or "phospholipase A2 group VI" or "iPLA2β" were searched across MEDLINE from June 23, 1997, to March 1, 2023. A total of 391 patients were identified, and 340 patients of them were finally included in the assessment.

RESULTS

The loss of function (LOF) mutation ratios were significantly different (p < 0.001), highest in INAD, followed by NBIA, aNAD, and EOP. Four ensemble scores (i.e., BayesDel, VARITY, ClinPred, and MetaRNN) were assessed to predict the deleteriousness of missense mutations and demonstrated significant differences (p < 0.001). Binary logistic regression analyses demonstrated that LOF mutations were independently associated with brain iron accumulation (p = 0.006) and ataxia (p = 0.025).

CONCLUSIONS

LOF or more deleterious missense mutations are more likely to promote the development of serious phenotype of PLAN, and LOF mutations are independently associated with brain iron accumulation and ataxia.

Associations between variants in levodopa metabolic pathway genes and levodopa-induced dyskinesia in Parkinson's disease

INTRODUCTION

Levodopa-induced dyskinesia (LID) is a common motor complication in Parkinson's disease (PD). Several genes in the levodopa metabolic pathway, such as COMT, DRDx and MAO-B, were reported associated with LID. However, there has been no systematic analyses between common variants in levodopa metabolic pathway genes and LID in a large sample of the Chinese population.

METHODS

Through the whole exome sequencing (WES) and target region sequencing, we aimed to explore the potential associations between common single nucleotide polymorphisms (SNPs) in the levodopa metabolic pathway and LID in Chinese PD individuals. Five hundred and two PD individuals were enrolled in our study, among them, 348 individuals underwent WES, and 154 individuals underwent target region sequencing. We acquired the genetic profile of 11 genes including COMT, DDC, DRD1-5, SLC6A3, TH and MAO-A/B. We established a stepwise strategy to filter SNPs, which finally included 34 SNPs in our analyses. And we used a two-stage study, with discovery (348 individuals with WES) and the replication (all 502 individuals) to confirm our findings.

RESULTS

Among the 502 PD individuals, 104 (20.7%) were diagnosed with LID. In the discovery stage, we found that COMT rs6269, DRD2 rs6275 and DRD2 rs1076560 were associated with LID. In the replication stage, associations between the three above-mentioned SNPs and LID were still present in all 502 individuals.

CONCLUSION

We demonstrated that in the Chinese population, COMT rs6269, DRD2 rs6275 and rs1076560 were significantly associated with LID. And rs6275 was reported associated with LID for the first time.

Quantitative Transcranial Sonography Evaluation of Substantia Nigra Hyperechogenicity Is Useful for Predicting Levodopa-Induced Dyskinesia in Parkinson Disease

Levodopa-induced dyskinesia (LID) is a common motor complication in Parkinson disease (PD). Abnormal substantia nigra hyperechogenicity (SN+), detected by transcranial sonography (TCS), plays an important role in the differential diagnosis of PD. The purpose of this study was to investigate the predictive performance of quantitative SN+ evaluations for LID. Five hundred sixty-two individuals were included in our analysis, and 198 individuals were followed up. These individuals were divided into two groups at baseline: the PD with LID (PD+LID) group and the PD without LID (PD-LID) group. The association between total hyperechogenic area of the SN on both sides (SN_T) and LID was analyzed by binary logistic analysis. A binary logistic regression model including SN_T was applied to establish a model for discriminating LID. At baseline, 105 (18.7%) individuals were diagnosed with LID. The PD+LID group had a longer disease duration, shorter education duration, higher levodopa equivalent doses, greater disease severity and larger SN_T. A model combining clinical features and SN_T was further established with better efficiency (area under the receiver operating characteristic curve = 0.839). One hundred ninety-eight individuals were followed up; individuals with a larger SN_T and a higher predicted probability were more likely to develop LID in our follow-up. Our study determined that quantitative TCS evaluation of SN echogenicity is useful in predicting LID in PD.

Inhibition of Spinal 5-HT3 Receptor and Spinal Dorsal Horn Neuronal Excitability Alleviates Hyperalgesia in a Rat Model of Parkinson's Disease

Pain in Parkinson's disease (PD) is increasingly recognized as a major factor associated with poor life quality of PD patients. However, classic therapeutic drugs supplying dopamine have limited therapeutic effects on PD-related pain. This suggests that there is a mechanism outside the dopamine system that causes pain in PD. Our previous study demonstrated that 6-OHDA induced PD model manifested hyperalgesia to thermal and mechanical stimuli and decreased serotonin (5-hydroxytryptamine; 5-HT) in the spinal dorsal horn (SDH). Several 5-HT receptor subtypes have been confirmed to be associated with nociception in the spinal cord, such as 5-HT1A receptor, 5-HT1B receptor, 5-HT2 receptor, 5-HT3 receptor, and 5-HT7 receptor. Most research has shown that 5-HT1A receptor and 5-HT3 receptor play a key role in pain transmission in the spinal cord. We hypothesized that hyperalgesia of 6-OHDA rats may be related to increased excitability of SDH neurons, and functional change of 5-HT3 receptor may reverse the hyperalgesia of 6-OHDA lesioned rats and decrease cell excitability of SDH neurons. To test this hypothesis, we used whole-cell patch-clamp and pharmacological methods to evaluate the effect of 5-HT3 receptor and 5-HT1A receptor on the hyperalgesia of 6-OHDA rats. The results suggested that increased excitability in SDH neurons could be reversed by 5-HT3 receptor antagonist ondansetron (20 μmol/L) and palosetron (10 μmol/L), but not 5-HT3 receptor agonist m-CPBG (30 μmol/L) and SR 57,727 (10 μmol/L), 5-HT1A receptor agonist 8-OH DPAT (10 μmol/L) and eptapirone (10 μmol/L) and 5-HT1A receptor antagonist WAY-100635 (10 μmol/L) and p-MPPI (10 μmol/L). Intrathecal injection of ondansetron (0.1 mg/kg) but not m-CPBG (0.1 mg/kg), 8-OH DPAT (0.1 mg/kg), and WAY-100635 (0.1 mg/kg) significantly attenuated the mechanical hyperalgesia and thermal hyperalgesia in 6-OHDA lesioned rats. In conclusion, the present study suggests that inhibition of spinal 5-HT3 receptor and SDH neuronal excitability alleviates hyperalgesia in PD rats. Our study provides a novel mechanism or therapeutic strategy for pain in patients with PD.

G2019S LRRK2 Mutation Enhances MPP+-Induced Inflammation of Human Induced Pluripotent Stem Cells-Differentiated Dopaminergic Neurons

Induced pluripotent stem cells (iPSCs) offer an unprecedented opportunity to mimic human diseases of related cell types, but it is unclear whether they can successfully mimic age-related diseases such as Parkinson’s disease (PD). We generated iPSCs lines from three patients with familial PD associated with the G2019S mutation in the LRRK2 gene and one age-matched healthy individual (control). During long-term culture, dopaminergic (DA) neurons differentiated from iPSCs of G2019S LRRK2 PD patients exhibited morphological changes, including a reduced number of neurites and neurite arborization, which were not evident in DA neurons differentiated from control iPSCs. To mimic PD pathology in vitro, we used 1-methyl-4-phenylpyridium (MPP⁺) to damage DA neurons and found that DA neurons differentiated from patients with G2019S LRRK2 mutation significantly reduced the survival rate and increased apoptosis compared with the controls. We also found that the mRNA level of inflammatory factors [interleukin (IL)-1β, tumor necrosis factor-α, cyclooxygenase-2, IL-6, and inducible NO synthase] with G2019S LRRK2 mutation were higher than control group after exposure to MPP⁺. Our study provides an in vitro model based on iPSCs that captures the patients’ genetic complexity and investigates the pathogenesis of familial PD cases in a disease-associated cell type.

[Study on the effect of AIDS preventive cascade services provided by social organizations for men who have sex with men in China]

Objective: To analyze the effect and main gaps of each stage in the AIDS prevention cascade for men who have sex with men (MSM) provided in intervention projects supported by the China AIDS Fund for non-governmental organizations (CAFNGO) and provide suggestions to improve the quality of cascade services and project management. Methods: Data were collected through the CAFNGO management information system and field interviews to analyze the differences in the number of MSM receiving HIV testing and confirming tests, the newly reported patients, and the number of antiviral treatment (ART) referrals of newly established reported patients among different social organization service areas. A service chain chart was also drawn. Results: Between 2016 and 2020, 1 508 MSM intervention projects were funded by CAFNGO, including 1 183 234 MSM being mobilized to receive HIV testing. However, only 68.8% (1 183 234/1 719 139) of the testing capacity of social organizations was covered by these projects. As a result, 55 783 HIV-positive MSM were detected in preliminary screening, and only 86.6% (48 327/55 783) received confirming tests. The proportion of newly reported infections was 3.8% (45 347/1 183 234). The ratio of antiviral treatment (ART) referrals for newly reported patients between 2017 and 2020 was 89.8% (32 719/36 444). 75.8%(1 143/1 508) of total MSM intervention projects were implemented by community-based organizations (Non-registered civil affairs departments). In comparison, organizations registered in civil affairs departments took up 24.2% (365/1 508) of the total MSM intervention projects. No significant difference was noticed in the proportion of newly reported infected (3.8% and 3.8%) and the ratio of ART referrals (89.7% and 89.9%) between community-based organizations and registered organizations' projects. But these two proportions are significantly different between these two types of organizations in some areas in China. Conclusions: The AIDS prevention cascade established in CAFNGO has effectively promoted the early detection and treatment of infected MSM. However, CAFNGO needs more financial support to extend testing coverage for MSM. Meanwhile, confirmation testing for positives in preliminary screening and ART referrals needs to be improved for newly reported patients. In addition, various capacity building needs to be provided for different social organizations.

Early-Life Stress Induces Prodromal Features of Parkinsonism in Ageing Rats

Early-life stress (ELS) can cause long-term effects on human health, ranging from adolescence to adulthood, and even to gerontic. Although clinical retrospective data suggest that ELS may be related to senile neurodegenerative diseases such as Parkinson's disease (PD), there are few prospective investigations to explore its real contribution to PD. Here, we investigated the behavioral, histochemical, neuromorphological, and transcriptional changes induced by maternal separation (MS), an ELS model. Without neurotoxin, MS rats showed behavioral alterations in olfaction, locomotion, and gait characters after depression compared with control rats. Based on neuroimaging and histochemistry, although we found that the dopaminergic system in the striatum was impaired after MS, the decrease of striatal dopamine level was ~33%. Consistently, tyrosine hydroxylase immunostaining positive neurons of MS rats in the substantia nigra showed deficit by about 20% in cell counting. Furthermore, using transcriptome sequencing, we discovered many differentially expressed genes (DEGs) of MS rats in the striatum significantly enriched in the pathway of dopaminergic synapse, and the biological process of locomotion and neuromuscular process controlling balance. Encouragingly, some representative DEGs relating to PD were singled out. These results suggest that ELS-depression rats potentially mimic some key features of prodromal stage of PD during natural senescence. In conclusion, our findings provide some novel insights into the future pathogenesis and therapeutic studies for PD related to depression.

Generalized EEG Slowing Across Phasic REM Sleep, Not Subjective RBD Severity, Predicts Neurodegeneration in Idiopathic RBD

PURPOSE

Idiopathic rapid eye movement sleep behavior disorder (iRBD) is the prodromal marker of α-synuclein degeneration with markedly high predictive value. We aim to evaluate the value of electroencephalography (EEG) data during rapid eye movement (REM) sleep and subjective RBD severity in predicting the conversion to neurodegenerative diseases in iRBD patients.

METHODS

At the baseline, iRBD patients underwent clinical assessment and video-polysomnography (PSG). Relative spectral power for nine frequency bands during phasic and tonic REM sleep in three regions of interest, slow-to-fast ratios, clinical and PSG variables were estimated and compared between iRBD patients who converted to neurodegenerative diseases (iRBD-C) and iRBD patients who remained disease-free (iRBD-NC). Receiver operating characteristic (ROC) curves evaluated the predictive performance of slow-to-fast ratios, and subjective RBD severity as assessed with RBD Questionnaire-Hong Kong.

RESULTS

Twenty-two (33.8%) patients eventually developed neurodegenerative diseases. The iRBD-C group showed shorter total sleep time (p < 0.001), lower stage 2 sleep percentage (p = 0.044), more periodic leg-movement-related arousal index (p = 0.004), increased tonic chin electromyelographic activity (p = 0.040) and higher REM density in the third REM episode (p = 0.034) than the iRBD-NC group. EEG spectral power analyses revealed that iRBD phenoconverters showed significantly higher delta and lower alpha power, especially in central and occipital regions during the phasic REM state compared to the iRBD-NC group. Significantly higher slow-to-fast ratios were observed in a more generalized way during the phasic state in the iRBD-C group compared to the iRBD-NC group. ROC analyses of the slowing ratio in occipital areas during phasic REM sleep yielded an area under the curve of 0.749 (p = 0.001), while no significant predictive value of subjective RBD severity was observed.

CONCLUSION

Our study shows that EEG slowing, especially in a more generalized manner during the phasic period, may be a promising marker in predicting phenoconversion in iRBD, rather than subjective RBD severity.

Cognitive Performance is Associated with Altered Cerebral Hemodynamics Assessed by Transcranial Ultrasound in Parkinson's Disease

PURPOSE

Cognitive impairment (CI) is a common but debilitating non-motor symptom in Parkinson's disease (PD). Although cerebrovascular functions are related to cognitive performance in healthy individuals, such a relation in PD remains elusive. This study aims to assess the association between cerebrovascular function and cognitive performance in PD individuals.

PATIENTS AND METHODS

Two-hundred-and-one PD individuals were retrospectively included. They were subsequently divided into two groups: PD with normal cognition (PD-NC) and PD with CI (PD-CI). Cerebral hemodynamic characteristics of the middle cerebral arteries were assessed by transcranial ultrasound. The association between scores in each cognitive domain and cerebral hemodynamic parameters was further analyzed using regression analyses. Additionally, a binary logistic regression model with backward stepwise procedure was applied to build the model for discriminating CI in PD individuals. An independent dataset of additional 46 PD individuals was used further.

RESULTS

The PD-CI group showed a relatively lower end-diastolic blood flow velocity (EDV, p < 0.05) and a higher resistive index (RI, p < 0.05) compared to the PD-NC group. RI showed significant associations with the memory item score of Montreal Cognitive Assessment (p < 0.05). A model combining clinical and hemodynamic variables was established with optimal efficiency (area under the curve, AUC = 0.651). Further replication of the model in an independent dataset yielded a great consistency (AUC = 0.704).

CONCLUSION

In our study, cerebrovascular functions were significantly associated with the cognitive performance in PD individuals, especially with the memory task. The established model was effective in identifying CI in PD individuals, which might be a potentially useful tool to screen the cognitive decline in PD individuals at an early stage of the disease. Further studies with larger sample sizes in different populations are warranted.

REM sleep without atonia and vestibular-evoked myogenic potentials: clinical brainstem dysfunction in early-stage Parkinson's disease and isolated REM sleep behavior disorder

OBJECTIVE

To determine whether the onset of rapid eye movement (REM) sleep behavior disorder (RBD) is associated with changes in brainstem neuronal pathway dysfunction as reflected by vestibular-evoked myogenic potentials (VEMPs) and to evaluate associations between VEMPs and REM sleep without atonia (RSWA) in patients with early-stage Parkinson's disease (PD) and isolated RBD (iRBD).

METHODS

Eighty-two early-stage PD patients, 40 iRBD patients, and 41 healthy control individuals underwent one-night video-polysomnography (vPSG) and VEMPs examination. We compared cervical (cVEMP), ocular (oVEMP), and masseter (mVEMP) VEMP parameters among PD with RBD (PD + RBD), PD without RBD (PD-RBD), iRBD, and control groups and analyzed correlations between VEMPs and RSWA in PD and iRBD groups.

RESULTS

The PD + RBD group showed delays in bilateral cVEMP (Lp13, Ln23, Rn23: all p < 0.05) and oVEMP (Ln10, Rn10, Rp15: all p < 0.05) peak latencies compared with the PD-RBD group. Total cVEMP scores were higher in the PD + RBD group than in the iRBD group (p = 0.033). In PD patients, phasic RSWA was correlated with total cVEMP scores (p = 0.003), and tonic RSWA was correlated with left oVEMP scores (p = 0.013).

CONCLUSIONS

Brainstem neurophysiology as evidenced by altered VEMPs in patients with PD and iRBD could reflect disease evolvement. Moreover, VEMPs alterations may vary depending on the presence of RBD in PD patients. The associations between altered RSWA and VEMP parameters highlight the meaningfulness of detecting brainstem dysfunction in early-stage PD.

Pramipexole regulates depression-like behavior via dopamine D3 receptor in a mouse model of Parkinson's disease

Depression is one of the strongest predictors of quality of life in patients with Parkinson's disease (PD). Despite the high prevalence of depression, there is no clear guidance for its treatment in PD because the evidence for the efficacy of most antidepressants remains insufficient. Pramipexole, a dopamine agonist, is one of the few drugs that has proven to be clinically useful. However, the underlying mechanisms of antidepressive effects of pramipexole are still unknown. A 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model, dopamine D2 receptor (DRD2) and D3 receptor (DRD3) knockout mice were used in our study. Compared with other dopamine D2-like receptor agonists and madopar, pramipexole improved depression-like behavior and alleviate bradykinesia in an MPTP-induced mouse model of PD. Pramipexole significantly improved depression-like behavior in DRD2^-/- mice but not in DRD3^-/- mice. These results demonstrate that the antidepressive effect of pramipexole is mediated by DRD3 but not DRD2. Our findings highlight the need to develop novel dopamine agonists specifically targeting DRD3 for the treatment of depression in PD in the future.

Induction of Parkinsonian-Like Changes via Targeted Downregulation of Astrocytic Glutamate Transporter GLT-1 in the Striatum

BACKGROUND

Previous investigations have suggested that decreased expression of glutamate transporter-1 (GLT-1) is involved in glutamate excitotoxicity and contribute to the development of Parkinson's disease (PD), GLT-1 is decreased in animal models of PD. GLT-1 is mainly expressed in astrocytes, and the striatum is a GLT-1-rich brain area.

OBJECTIVE

The aim was to explore the function and mechanism of astrocytic GLT-1 in PD-like changes.

METHODS

In the study, PD-like changes and their molecular mechanism in rodents were tested by a behavioral assessment, micro-positron emission tomography/computed tomography (PET/CT), western blotting, immunohistochemical and immunofluorescence staining, and high performance liquid chromatography pre-column derivatization with O-pthaldialdehida after downregulating astrocytic GLT-1 in vivo and in vitro.

RESULTS

In vivo, after 6 weeks of brain stereotactic injection of adeno-associated virus into the striatum, rats in the astrocytic GLT-1 knockdown group showed poorer motor performance, abnormal gait, and depression-like feature; but no olfactory disorders. The results of micro-PET/CT and western blotting indicated that the dopaminergic system was impaired in astrocytic GLT-1 knockdown rats. Similarly, tyrosine hydroxylase (TH) positive immune-staining in neurons of astrocytic GLT-1 knockdown rats showed deficit in cell count. In vitro, knockdown of astrocytic GLT-1 via RNA interference led to morphological injury of TH-positive neurons, which may be related to the abnormal calcium signal induced by glutamate accumulation after GLT-1 knockdown. Furthermore, the GLT-1 agonist ceftriaxone showed a protective effect on TH-positive neuron impairment.

CONCLUSION

The present findings may shed new light on the future prevention and treatment of PD based on blocking glutamate excitotoxicity.

[Relationship between emotional apathy and motor symptoms, sleep and cognitive function in patients with early Parkinson's disease]

Objective: To study the relationship between emotional apathy and motor symptoms, sleep, and cognitive function in patients with early Parkinson's disease (PD). Methods: One hundred and twenty-nine early PD patients who were treated in the Second Affiliated Hospital of Soochow University from June to October 2020 were included, including 82 male and 47 female patients. The emotional apathy was assessed by modified apathy rating scale (MAES). The above 129 patients were divided into 67 patients in the PD with emotional apathy group (MAES>14 points) and 62 patients in the PD without emotional apathy group (MAES≤ 14 points). Age, gender, course of disease and levodopa equivalent dose were also collected. Hoehn-Yahr stage and unified Parkinson's disease rating scale PartⅢ(UPDRS-Ⅲ), Pittsburgh Sleep Quality Index (PSQI), polysomnography, and Montreal Cognitive Assessment Scale (MoCA) were used to evaluate the motor symptoms, sleep and cognitive functions of patients with early PD, and the clinical characteristics of patients with early PD with apathywere determined. Results: Compared with PD patients without apathy, those with apathy had longer disease duration [M(Q₁,Q₃)][5.0 (3.0, 7.0) years vs 3.0 (2.0, 5.0) years, P=0.006] and severer motor symptoms [20.0 (10.0, 28.0) vs 14.0 (8.5, 23.0), P=0.047]. There was no significant difference in PSQI score between the two groups. Among the 33 patients who completed polysomnography, compared with PD patients without apathy (n=16), those with apathy (n=17) had a longer rapid eye movement (REM) sleep latency [150 (124, 184) min vs 87 (57, 133) min, P=0.035)] and more frequent periodic limb movements in the REM phase(P=0.042).The REM sleep ratio (r=0.373, P=0.042), apnea-hypopena index (AHI)(r=0.374, P=0.046) and oxygen deficit index (r=0.409, P=0.025) were positively correlated with the degree of apathy in PD patients. PD patients with apathy had relatively poorer performance in cognition assessment than those without apathy and total MoCA score was inversely correlated with the degree of apathy (r=-0.231, P=0.017). Conclusion: Early PD patients with apathy have objective sleep disorders dominated by REM sleep disorders, which can have a negative impact on cognitive function.

Effect of Sleep-Disordered Breathing During Rapid Eye Movement Sleep and Non-Rapid Eye Movement sleep on Acute Ischemic Stroke

OBJECTIVES

Sleep-disordered breathing adversely impacts stroke outcomes. We investigated whether sleep-disordered breathing during rapid eye movement sleep and non-rapid eye movement sleep differentially influenced stroke outcomes.

MATERIALS AND METHODS

Acute ischemic stroke patients who finished polysomnography within 14 days of stroke onset from April 2010 to August 2018 were reviewed. Patients were divided into four groups according to apnea-hypopnea index during rapid eye movement sleep and non-rapid eye movement sleep. The modified Rankin Scale was used to evaluate short-term outcome. During January and April 2019, another follow-up was performed for long-term outcomes, including stroke-specific quality-of-life scale, modified Rankin Scale, stroke recurrence and death.

RESULTS

Of 140 patients reviewed, 109 were finally recruited. Although patients with sleep-disordered breathing during non-rapid eye movement sleep only and with sleep-disordered breathing during both rapid eye movement sleep and non-rapid eye movement sleep had higher apnea-hypopnea indices and more disrupted sleep structures, short-term and long-term outcomes did not significantly different between four groups. In Logistic regression analysis, apnea-hypopnea index (p = 0.013, OR 1.023, 95%CI 1.005-1.042) was found independently associated with short-term outcome. Rapid eye movement sleep latency (p = 0.045, OR 0.994, 95%CI 0.987-1.000) was found independently associated with quality of life. Apnea-hypopnea indices during rapid eye movement sleep or non-rapid eye movement sleep were not significantly associated with short-term or long-term outcomes.

CONCLUSIONS

Apnea-hypopnea index is an independent risk factor of short-term outcome of acute ischemic stroke while sleep-disordered breathing during rapid eye movement sleep and non-rapid eye movement sleep do not affect stroke outcomes differently.

[Transcranial sonographic characteristics of Parkinson's disease with symptoms of restless legs syndrome]

Objective: To evaluate the transcranial sonographic characteristics in patients with Parkinson's disease (PD) with symptoms of restless legs syndrome (RLS). Methods: Patients with diagnosis of definite PD from the Second Affiliated Hospital of Soochow University and 3 other participating hospitals between September 2018 and December 2019 were consecutively enrolled. Concurrent RLS symptoms were determined using Non-motor Symptoms Questionnaire. Transcranial sonography (TCS) and clinical assessments were performed during the same time and the related variables were compared between the two groups using t-test, non-parametric test, Chi-square test and Spearman correlation analysis, respectively. Results: Among 349 patients with PD, the prevalence of RLS symptoms was 22.6%. Compared to patients without RLS symptoms, those with RLS had longer disease duration (43.0 (24.0, 91.0) months vs 37.0 (20.0, 60.0) months, P<0.05) and higher Hoehn-Yahr stage (2.5 (2.0, 3.0) vs 2.0 (1.5, 2.5), P<0.01).TCS revealed that patients with RLS symptoms were more likely to have abnormality in the raphe nucleus (21.50% vs 7.78%, χ²=15.9, P<0.001) and increased third ventricle width ((6.22±1.97) mm vs (5.16±1.90) mm, P<0.001). No significant differences were found regarding parameters of substantia nigra. Conclusions: Concurrent RLS symptoms are common in PD patients. Abnormal echogenicity of raphe nucleus and increased third ventricle width could be characteristics of TCS in PD patients with RLS symptoms.

Sex and onset-age-related features of excessive daytime sleepiness and night-time sleep in patients with Parkinson's disease

Background

The clinical characteristics of Parkinson’s disease (PD) differ between men and women, and late- and early-onset patients, including motor symptoms and some nonmotor symptoms, such as cognition, anxiety, and depression.

Objective

To explore the features of excessive daytime sleepiness (EDS) and night-time sleep quality in PD patients of different sexes and age at onset (AAO).

Methods

Demographic data and clinical characteristics of 586 PD patients were collected. Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI) were used to investigate the daytime drowsiness and nocturnal sleep. Multivariate logistic regression analysis was used to explore the risk factors of EDS and poor night-time sleep quality.

Results

Sleep disorders were common in PD patients. EDS was more prominent in men than in women. There was no significant difference in ESS scores between late-onset PD (LOPD) and early-onset PD. LOPD patients had a higher probability of poor night-time sleep quality. Male sex, disease duration, and depression were risk factors for EDS. In all patients of both sexes and all AAO, depression was a risk factor for poor night-time sleep.

Conclusion

More attention should be paid to sleep disorders of PD patients, especially male LOPD patients. Depression is a common risk factor for EDS and poor sleep quality in PD patients.

Depression Induced by Chronic Unpredictable Mild Stress Increases Susceptibility to Parkinson's Disease in Mice via Neuroinflammation Mediated by P2X7 Receptor

The relationship between depression and Parkinson's disease (PD) is complicated and still not fully understood. We investigated whether depression increased the susceptibility to PD and whether this resulted from neuroinflammation mediated by purinergic ligand-gated ion channel 7 receptor (P2X7R) of microglia in mice. Depression was induced by a 14-day chronic unpredictable mild stress (CUMS), and PD was induced by 1-day acute injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Before MPTP administration, some mice were given brilliant blue G (BBG), a P2X7R inhibitor. Changes in depression and motor function were assessed by sucrose preference, tail suspension, open field, and rotating rod tests. Differences in P2X7R, caspase-1, NLRP3 inflammasome, interleukin (IL)-1β, tyrosine hydroxylase (TH), and microglial activation among experimental groups were detected by immunofluorescence, immunohistochemistry, western blotting, and ELISA. CUMS-induced depression-like behavior, and MPTP induced PD in mice. CUMS mice had no motor dysfunction, but the dyskinesia and loss of TH-positive neurons in the substantia nigra after MPTP treatment were more serious than with MPTP treatment alone. With behavioral changes, neuroinflammatory markers, such as caspase-1, NLRP3 and IL-1β increased, and microglia were activated as well as expression of P2X7R increased. Additionally, BBG partly reversed the above abnormalities. Summarily, we suggest that CUMS aggravates dyskinesia and death of dopaminergic neurons in an MPTP-PD model via promoting activation of microglia and neuroinflammation, which may be mediated by P2X7R. Inhibition of P2X7R could be a new control strategy for PD associated with depression.

Correlations between retinal nerve fiber layer thickness and cognitive progression in Parkinson's disease: A longitudinal study

BACKGROUND

Retinal abnormalities measured by optical coherence tomography (OCT) have been detected in both Parkinson's disease (PD) and Alzheimer's disease (AD). Cognitive impairment is not only found in AD, but 75-90% of PD patients will also develop dementia in the late stage of disease. We assessed whether baseline retinal nerve fiber layer (RNFL) thickness predicted worsening of cognitive status over time and the correlation between RNFL thickness and the detailed impaired cognitive domains in PD.

METHODS

RNFL thickness was measured using high-definition OCT in 78 non-dementia PD patients. Clinical and cognitive assessments were performed at baseline and at 3.61 ± 0.65 years follow-up. Linear mixed-effects models were used to examine associations between RNFL thickness and the changes in cognitive test scores, after adjusting for age, sex, disease duration and education.

RESULTS

Analysis of outcomes according to baseline RNFL tertiles showed worse performance in global cognitive tests, delayed memory, and executive functions in patients with a thin RNFL. During follow-up, greater cognitive deterioration was found in thin RNFL tertile patients. Lower baseline average RNFL thickness was associated with greater annualized decline in Mini-Mental State Examination and Montreal Cognitive Assessment.

CONCLUSION

The correlation between RNFL thickness and cognitive dysfunction suggests that OCT may be useful for predicting cognitive dysfunction in PD patients.

[Effects of sleep quality and mood of patients with Parkinson's disease on their caregivers]

Objectve: To evaluate the relationship of Parkinson's disease(PD) patients' sleep quality and depression with burden, quality of life, and depression of their caregivers. Methods: A total of 120 PD patients (68 males and 52 females) and their caregivers (48 males and 72 females) from Changshu Hospital Affiliated to Nanjing University of Chinese Medicine between January 2017 and June 2019 were recruited. Patients' sleep quality, depression and quality of life was evaluated. Burden, quality of life, quality of sleep, and depression of caregivers were assessed by the Caregivers Burden Questionnaire (CBI), Health Survey Brief (SF-36), Pittsburgh Sleep Quality Index (PQS1) and Hamilton Depression Scale (HAMD), meanwhile, the correlation between relevant factors was analyzed. Results: The CBI of caregivers was positively correlated with the unified Parkinson's disease rating scale (UPDRS)-Ⅲ scores of PD patients (r=0.436, P<0.05). The CBI, SF-36GH, SF-36MH, HAMD and PSQI scores of caregivers were positively correlated with Parkinson's disease sleep scale (PDSS) scores of PD patients (r=0.546, 0.762, 0.528, 0.562 and 0.522, respectively, all P<0.01). The caregiver's CBI score was positively correlated with PD patients' Epworth sleepiness score (ESS) score (r=0.442, P<0.05), and caregiver's CBI, SF-36GH, SF-36MH, HAMD, PSQI scores were positively correlated with PD patients' HAMD scores (r=0.765, 0.813, 0.635, 0.884 and 0.601, respectively, all P<0.01). The caregiver's CBI score was positively correlated with the PDQ-39 score of PD patients (r=0.834, 0.452, 0.463, 0.421 and 0.387, respectively, all P<0.05). Multiple regression analysis indicated that the caregiver's CBI score was significantly correlated with the patient's PDQ-39, PDSS and HAMD scores (r=0.512, 0.645 and 0.635, respectively, all P<0.01), and the caregiver's SF-36GH score was significantly correlated with the patient's PDQ-39, PDSS and HAMD scores (r=0.452, 0.682 and 0.506, respectively, all P<0.01). The caregiver's SF-36MH score was significantly correlated with the patient's PDQ-39, PDSS and HAMD scores (r=0.426, 0.608 and 0.598, respectively, all P<0.01). There was significant correlations between the caregiver's HAMD score and the patient's PDSS and HAMD scores (r=0.568 and 0.496, both P<0.01), and the PSQI score of the caregiver was significantly correlated with the PDSS and HAMD scores of the patient (r=0.532 and 0.461, both P<0.01). Conclusions: This current study underscores the presence of a significant relationship of patient's sleep quality with caregiver's burden, quality of life, depression and sleep quality. Specifically, sleep quality and depression of the patients are independent predictors for burden, quality of life and sleep quality of the caregivers.

Echogenicity Changes in Brainstem Raphe Detected by Transcranial Parenchymal Sonography and Clinical Characteristics in Parkinson's Disease

Background: Decreased brainstem raphe (BR) echogenicity detected by transcranial parenchymal sonography (TCS) is associated with depression in psychiatric and neurologic diseases. However, previous studies focusing on the relationship between motor and non-motor symptoms and echogenicity changes in BR in patients with PD yielded controversial results.

Objectives: To investigate the relationship between echogenicity changes in BR detected by TCS and motor and a series of non-motor symptoms in patients with PD.

Methods: Consecutive PD patients were recruited from the Second Affiliated Hospital of Soochow University. Demographic information and Motor and non-motor symptoms for all subjects were collected. TCS was used to detect the echogenicity changes in BR in PD patients.

Results: One hundred and thirty-five consecutive patients with PD were enrolled in the study. The BR abnormal rate was significantly higher in PD patients with anxiety (p = 0.003) or depression (p = 0.022) than patients without. Spearman correlation analyses showed that Hamilton Rating Scale for Depression(HRSD) (r = 0.274, p = 0.002) and Parkinson's Disease Questionnaire 39-item(PDQ-39) (r = 0.208, p = 0.034) scores were positively correlated with abnormal BR echogenicity. Multivariate logistic regression analyses showed that HRSD and HAMA scores were associated with BR hypoechogenicity, the corresponding odds ratios (confidence intervals) were 1.07 (95% CI, 1.01–1.13) and 1.10(1.01–1.18), respectively. However, the PDQ-39 score was not associated with BR hypoechogenicity.

Conclusion: The abnormal reduction in BR echogenicity detected by TCS is associated with depression and anxiety, but not motor symptoms in PD patients.

Association of inflammatory factors and aging in Parkinson's disease

BACKGROUND

Parkinson's disease as a common neurodegenerative disease, has been found to be related to inflammation. So we observed the characteristics of inflammatory indexes in patients with Parkinson's disease and investigated the relationship between inflammatory cytokines and clinical characteristics. Emerging data may reveal novel neuroinflammatory pathways and identify new targets for treatment of Parkinson's disease.

METHODS

We examined the inflammatory indexes in 183 patients and 89 healthy controls in association with clinical characteristics.

RESULTS

Patients had significantly higher levels of monocytes, neutrophils, high-sensitivity C-reactive protein, and monocyte-to-high-density lipoprotein ratios (p < 0.01) and lower levels of lymphocytes (p = 0.02) than the controls. There were no significant differences in age, leukocytes, high-density lipoprotein, or neutrophil-lymphocyte ratios between the two groups (p > 0.05). Multivariate logistic regression analysis of these indicators revealed that lymphocyte level was a protective factor (p = 0.025, OR=-0.679), while high-sensitivity C-reactive protein level was a risk factor (p = 0.000, OR=1.168) for Parkinson's disease. High-sensitivity C-reactive protein levels were higher in older Parkinson's disease patients.

CONCLUSION

High-sensitivity C-reactive protein is positively related to the risk of Parkinson's disease, especially in aging patients. High-sensitivity C-reactive protein is a potential biomarker for disease progression and treatment response for Parkinson's disease.

Substantia nigra echogenicity is associated with serum ferritin, gender and iron-related genes in Parkinson's disease

Substantia nigra (SN) hyperechogenicity is present in most Parkinson’s disease (PD) cases but is occasionally absent in some. To date, age, gender, disease severity, and other factors have been reported to be associated with SN hyperechogenicity in PD. Previous studies have discovered that excess iron deposition in the SN underlies its hyperechogenicity in PD, which may also indicate the involvement of genes associated with iron metabolism in hyperechogenicity. The objective of our study is to explore the potential associations between variants in iron metabolism-associated genes and SN echogenicity in Han Chinese PD. Demographic profiles, clinical data, SN echogenicity and genotypes were obtained from 221 Han Chinese PD individuals with a sufficient bone window. Serum ferritin levels were quantified in 92 of these individuals by immunochemical assay. We then compared factors between PD individuals with SN hyperechogenicity and those with SN hypoechogenicity to identify factors that predispose to SN hyperechogenicity. Of our 221 participants, 122 (55.2%) displayed SN hyperechogenicity, and 99 (44.8%) displayed SN hypoechogenicity. Gender and serum ferritin levels were found to be associated with SN hyperechogenicity. In total, 14 genes were included in the sequencing part. After data processing, 34 common single nucleotide polymorphisms were included in our further analyses. In our data, we also found a significantly higher frequency of PANK2 rs3737084 (genotype: OR = 2.07, P = 0.013; allele: OR = 2.51, P = 0.002) in the SN hyperechogenic group and a higher frequency of PLA2G6 rs731821 (genotype: OR = 0.45, P = 0.016; allele: OR = 0.44, P = 0.011) in the SN hypoechogenic group. However, neither of the two variants was found to be correlated with serum ferritin. This study demonstrated that genetic factors, serum ferritin level, and gender may explain the interindividual variability in SN echogenicity in PD. This is an explorative study, and further replication is warranted in larger samples and different populations.

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 misfolded α-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.

Hypertension with Hyperhomocysteinemia Increases the Risk of Early Cognitive Impairment after First-Ever Ischemic Stroke

BACKGROUND

Hypertension and hyperhomocysteinemia (HHcy) are independent risk factors of stroke and are associated with each other. Although evidence suggests that they are related to cognitive impairment, the relationship between hypertension accompanied with HHcy and poststroke cognitive impairment (PSCI) is unclear.

OBJECTIVE

To define the relationship between hypertension with HHcy and early cognitive impairment after acute cerebral infarction.

MATERIALS AND METHODS

Our study enrolled 232 patients with acute first-ever ischemic stroke. Patients were assigned to 3 groups by blood pressure and homocysteine (Hcy) levels: hypertension with HHcy, simple hypertension, or control. Cognition was assessed by the Montreal cognitive assessment at admission and at 3- and 6-month follow-ups.

RESULTS

The hypertension with HHcy group exhibited the highest incidence of early cognitive impairment (simple hypertension: p = 0.000; control: p = 0.000). This group also had lower visual space/executive scores than the simple hypertension group (p = 0.000) and lower delayed recall scores than the control group (p = 0.011). Multivariate analysis showed that hypertension with HHcy (OR 7.797; 95% CI 2.917-20.843; p = 0.000), the level of serum Hcy (OR 1.063; 95% CI 1.109-1.109; p = 0.005), education years (OR 0.797; 95% CI 0.722-0.880; p = 0.000), and Fazekas scale of leukoaraiosis (OR 1.648; 95% CI 1.239-2.191; p = 0.001) were independent influencing factors of early PSCI; however, simple hypertension (OR 1.183, 95% CI 0.208-6.737; p = 0.850) and simple HHcy (OR 1.112, 95% CI 0.181-6.810; p = 0.909) were not.

CONCLUSION

Patients with both hypertension and HHcy are at an increased risk of early cognitive impairment after acute first-ever ischemic stroke.

Progressive Changes in the Retinal Structure of Patients with Parkinson's Disease

BACKGROUND

Many optical coherence tomography (OCT) studies have reported alterations in the retinal nerve fiber layer (RNFL) in Parkinson's disease (PD) and other neurodegenerative diseases. However, whether retinal alterations are a biomarker for PD is still controversial.

OBJECTIVE

To investigate potential correlations between PD and morphological changes in retina using OCT and to determine its usefulness as a biomarker of disease progression in PD.

METHODS

We performed a cross-sectional study on patients with PD (N = 37) and age-matched controls (N = 42), followed by a longitudinal study of the PD patients (N = 22) over approximately 2.5 years.

RESULTS

The average retinal nerve fiber layer (RNFL) thickness (p < 0.001), total macular thickness (p = 0.001), and macular volume (p = 0.001) were decreased in PD patients compared to controls and had further decreased at the follow-up visit (p < 0.05 for all). The average RNFL thickness and the total thickness of macular were negatively correlated with age in PD patients at baseline. Linear regression analysis revealed that age (p = 0.002, p = 0.003, respectively) and LEDD (p = 0.011, p = 0.013, respectively) were correlated to total thickness and volume of macular in 22 PD patients in the follow-up study. However, no correlation was found between RNFL and other parameters.

CONCLUSIONS

PD progression is associated with pronounced retinal structure changes, which can be quantified by OCT. Patterns of RNFL and macular damage detected by the noninvasive technology of OCT can be a useful biomarker for evaluating the progression of PD.

Nicotine improved the olfactory impairment in MPTP-induced mouse model of Parkinson's disease

Olfactory impairment is an early feature of patients with Parkinson's disease (PD). Retrospective epidemiological studies reported lower scores on the University of Pennsylvania Smell Identification Test (UPSIT) in non-smokers than smokers with PD and showed an inverse correlation between susceptibility to PD and a person's history of smoking. But the mechanisms by which cigarettes affect olfaction in PD are not fully understood. So we investigated the effect of nicotine on the olfactory function in 1-methyl-4-phenyl-1, 2, 3, 6 tetrahydropyridine (MPTP)-treated mice. We observed that nicotine improved locomotor activity and protection against dopaminergic neuron loss in the midbrain in MPTP-treated mice. Compared to controls, MPTP-treated mice showed a deficit of odor discrimination and odor detection, which were alleviated by nicotine treatment. But no significant changes were found in olfactory memory in MPTP-treated mice. Moreover, we detected a marked decrease of Choline acetyltransferase (ChAT) expression in the olfactory bulb (OB) in MPTP-treated mice, which was also attenuated by nicotine administration. In addition, nicotine ameliorated the loss of cholinergic neurons and dopaminergic innervation in the horizontal limb of the diagonal band (HDB), which is the primary origin of cholinergic input to the OB. Our results suggested that nicotine could improve the olfactory impairment by protecting cholinergic systems in the OB of MPTP-treated mice. And nicotine protection of cholinergic systems in the OB is relevant to attenuating dopaminergic neuron loss in the midbrain and HDB.

A Critical Role of Autophagy in Regulating Microglia Polarization in Neurodegeneration

Neuroinflammation and autophagy dysfunction are closely related to the development of neurodegeneration such as Parkinson’s disease (PD). However, the role of autophagy in microglia polarization and neuroinflammation is poorly understood. TNF-α, which is highly toxic to dopaminergic neurons, is implicated as a major mediator of neuroinflammation in PD. In this study, we found that TNF-α resulted in an impairment of autophagic flux in microglia. Concomitantly, an increase of M1 marker (iNOS/NO, IL-1β, and IL-6) expression and reduction of M2 marker (Arginase1, Ym1/2, and IL-10) were observed in TNF-α challenged microglia. Upregulation of autophagy via serum deprivation or pharmacologic activators (rapamycin and resveratrol) promoted microglia polarization toward M2 phenotype, as evidenced by suppressed M1 and elevated M2 gene expression, while inhibition of autophagy with 3-MA or Atg5 siRNA consistently aggravated the M1 polarization induced by TNF-α. Moreover, Atg5 knockdown alone was sufficient to trigger microglia activation toward M1 status. More important, TNF-α stimulated microglia conditioned medium caused neurotoxicity when added to neuronal cells. The neurotoxicity was further aggravated when Atg5 knockdown in BV2 cells but alleviated when microglia pretreatment with rapamycin. Activation of AKT/mTOR signaling may contribute to the changes of autophagy and inflammation as the AKT specific inhibitor perifosine prevented the increase of LC3II (an autophagic marker) in TNF-α stimulated microglia. Taking together, our results demonstrate that TNF-α inhibits autophagy in microglia through AKT/mTOR signaling pathway, and autophagy enhancement can promote microglia polarization toward M2 phenotype and inflammation resolution.

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.

Genetic analysis of LRRK2 in Parkinson's disease in Han Chinese population

Mutations in Leucine-rich repeat kinase 2 (LRRK2) are recognized as the most frequent genetic factors contributing to Parkinson's disease (PD). The aim of our study was to explore LRRK2 variants in PD patients within the mainland Han Chinese population. The whole coding regions of LRRK2 from 296 PD patients were sequenced by targeted regions sequencing and exome sequencing. Eighteen rare variants were identified in 27 PD patients, and 13 of them (M100T, L153W, A459S, S722N, R792K, C925Y, R981K, S1007T, V1447M, R1677S, N2308D, N2313S, and S2350I) were firstly reported in PD. We also tried to explore the genotype-phenotype associations of LRRK2 variants in our data and found that PD with common and rare LRRK2 variants was more likely to have motor fluctuation and nonmotor symptoms. The identification of novel variants in LRRK2 suggests that this gene plays an important role in the pathogenesis and phenotype of PD in Han Chinese population, and our data also rang the alarm bell-more attention should be paid to the whole coding regions of LRRK2.

Analysis of nocturnal hypokinesia and sleep quality in Parkinson's disease

Nocturnal hypokinesia/akinesia and sleep disorder are believed to be common in Parkinson's disease (PD), but are often underestimated. To date, only a few studies have focused on nocturnal symptoms related to motor function and sleep quality in PD patients, and the assessments were based mainly on the subjective descriptions of the patients. In this study, we assessed the relationships between motor symptoms and sleep quality in 29 PD patients (17 PD patients reporting impaired bed mobility (IBM) and 12 patients without IBM). All the participants were monitored using multisite inertial sensors and polysomnography in sleep-monitoring rooms for whole night. Compared with PD-IBM patients, PD+IBM patients tended to have fewer turning-over episodes and smaller degree turns. Meanwhile, PD+IBM patients had worse Pittsburgh Sleep Quality Index (PSQI) and Parkinson's Disease Sleep Scale (PDSS) scores, and less total sleep time (TST) than PD-IBM patients. Spearman correlation analyses found that the number of turning-over events showed negative correlations with disease duration (r = -0.378, P < 0.05) and Unified Parkinson's Disease Rating Scale (UPDRS) axial scores (r = -0.370, P < 0.05). Moreover, TST (r = 0.505, p < 0.05) and sleep efficiency (SE) (r = 0.473, p < 0.05) positively correlated with the number of turns in bed. Multivariate linear regression analyses showed that UPDRS axial scores and the number of turns were significantly associated with TST (both p < 0.05). In conclusion, the number of turns in bed and UPDRS axial scores were two significant factors affecting sleep quality. Multisite inertial sensors can be used to quantitatively evaluate nocturnal motor functions in PD patients.

Investigation of non-motor symptoms in first-degree relatives of patients with Parkinson's disease

OBJECTIVE

Non-motor symptoms (NMS) are important prodromal characteristics of Parkinson's disease (PD). However, the incidence of NMS in first-degree relatives, such as siblings of PD patients, is still unknown.

METHODS

A total of 98 PD patients of the Affiliated Hospital of Yangzhou University were recruited; 210 siblings of these patients were included in a first-degree relatives (FDR) group and 250 healthy individuals were included in a control group. Various scales were used to assess NMS, including depression, anxiety, cognitive function, sleep status, constipation, daytime sleepiness, Rapid-Eye-Movement Sleep Behavior Disorder (RBD), and Restless Legs Syndrome (RLS).

RESULTS

NMS were more common in the PD group than the control group. The incidence of anxiety (OR = 3.434, 95%CI: 2.058-5.731, P < 0.001), depression (OR = 2.438, 95%CI: 1.289-4.609, P = 0.005), and RBD (OR = 4.120, 95%CI: 1.897-8.945, P < 0.001) was higher in the FDR group than the control group. There were non-significant differences in constipation, cognitive impairment, sleep disorder, daytime sleepiness, and RLS between the two groups. The incidence of RLS in FDR of PD with an age of onset <60 years was higher than in the controls (OR = 2.273, 95%CI: 1.107-4.667, P = 0.023).

CONCLUSIONS

Siblings of PD are more likely to suffer from anxiety, depression and RBD than the general population. RLS is more common in siblings of PD with onset age<60 than in the general population. It is speculated that PD patients and their siblings have common pathogenic genetic factors and early living environment for neurodegeneration.

A novel p.L216I mutation in the glucocerebrosidase gene is associated with Parkinson's disease in Han Chinese patients

OBJECTIVES

Pathogenic mutations in the glucocerebrosidase (GBA) gene are associated with Parkinson's disease (PD), of which L444P and N370S are the most frequently observed in patients with PD. The aim of this study was to systematically explore variations in the coding regions of GBA in Han Chinese patients with PD, as well as to expand the GBA mutation spectrum.

MATERIAL AND METHODS

A total of 213 Han Chinese patients with PD and 348 controls were enrolled in the study. Whole coding regions of GBA were captured and sequenced by target region sequencing. Sanger sequencing was also used to confirm the identified variants.

RESULTS

We identified a novel variant (c. C646A; p.L216I; NM_001171811.1) of GBA in two unrelated patients, which was not observed in the controls. Both patients had early-onset PD and neither exhibited any motor-related symptoms. However, we did not find an L444P or N370S mutations in our patients.

CONCLUSIONS

The p.L216I mutation is a novel GBA mutation, which we identified in two Han Chinese patients with PD. The patients exhibited similar characteristics, which differed from those seen in patients with other GBA mutations. Future work is needed to investigate this mutation further, as well as larger cohort studies to explore other GBA mutations associated with PD in the Han Chinese and in other populations.

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, Bmal1 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 of Bmal1, 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.

Poor nighttime sleep is positively associated with dyskinesia in Parkinson's disease patients

BACKGROUND

Dyskinesia is a troublesome complication of long-term dopaminergic medications in Parkinson's disease (PD) patients. Many factors are reported to be associated with dyskinesia in PD.

OBJECTIVE

To investigate the association between sleep quality and dyskinesia in patients with PD.

METHODS

Four hundred twenty-five patients with PD were enrolled in this study. Demographic information was collected. Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr (H-Y) stage scale were also performed. Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI) were applied to evaluate daytime sleepiness and overall nighttime sleep quality, respectively, in PD patients.

RESULTS

Patients with dyskinesia tended to have a longer duration of disease, higher daily levodopa-equivalent dose (LED), H-Y stage, UPDRS II and PSQI score, and a higher percentage of levodopa treatment than those without dyskinesia. After adjusting for age, sex, age at onset of PD, disease duration, UPDRS I, UPDRS II, UPDRS III, cigarette smoking, use of different antiparkinsonian drugs, phenotype, daily LED, and restless leg syndrome (RLS), PSQI score was still associated with dyskinesia, with corresponding ORs 1.111 (95% CI, 1.004-1.229) as a continuous variable, and 2.469 (95% CI, 1.051-5.800) as a categorical variable, respectively. Further analysis of PSQI components showed that subjective sleep quality and sleep latency were associated with dyskinesia in PD patients.

CONCLUSIONS

Our data showed that poor nighttime sleep is positively associated with dyskinesia in PD patients. Attention to the management of nighttime sleep quality may be beneficial to dyskinesia in patients with PD.

Serum sodium and chloride are inversely associated with dyskinesia in Parkinson's disease patients

OBJECTIVE

We aim to report and evaluate the associations between serum sodium and chloride and dyskinesia in patients with Parkinson's disease. One hundred and two patients with Parkinson's disease were enrolled in this study.

METHODS

Patients' serum electrolytes including sodium, calcium, potassium, magnesium, and chloride were measured. Other demographic information was collected, and Unified Parkinson's disease rating scale and Hoehn and Yahr stage scale were also performed.

RESULTS

Patients with dyskinesia tended to have longer duration of disease, higher daily levodopa-equivalent dose, and Hoehn-Yahr stage, with lower serum sodium than those without dyskinesia. Spearman correlation analyses showed that serum sodium inversely correlated with duration of disease (r = -.218, p = .028), and positively correlated with serum chloride levels (r = .565, p < .001). Univariate logistic regression analysis found that duration of disease, daily levodopa-equivalent dose, serum sodium, and serum chloride were associated with dyskinesia in Parkinson's disease patients (p < .05 for all). After adjusting for age, sex, age at onset of Parkinson's disease, medical history, and other covariates, serum sodium and chloride were still associated with dyskinesia, with corresponding Odd ratios 0.783 (95% confidence intervals, 0.642-0.955) and 0.796 (95% confidence intervals, 0.652-0.972), respectively.

CONCLUSION

Our findings indicated that serum sodium and chloride levels were inversely associated with dyskinesia in patients with Parkinson's disease. Further studies with large samples and range of serum sodium and chloride are needed.

Odor selectivity of hyposmia and cognitive impairment in patients with Parkinson's disease

Objective

Hyposmia is one of the earliest non-motor features of Parkinson’s disease (PD) and can precede the onset of motor symptoms by years. Most of the current olfactory detection tests are targeted at Western populations. The exact relationship between hyposmia and cognitive impairment is unknown. The purpose of the study was to find bromines that can effectively identify olfactory dysfunction and investigate the relationship between hyposmia and cognitive function in early, non-demented, drug-naïve patients with PD in the People’s Republic of China.

Methods

Sixty-three early, non-demented, drug-naïve patients with PD and 55 healthy controls were enrolled in the study. The T&T olfactometer and a Chinese version of Montreal Cognitive Assessment (MoCA) were applied to assess subjects’ olfactory and cognitive functions. Patients with PD also completed the Modified Unified Parkinson’s disease-rating scale (UPDRS) and Hoehn and Yahr (H&Y) scale.

Results

Patients with PD had lower scores of visuospatial and executive function (p=0.000), attention (p=0.03), and delayed recall (p=0.001) than controls. β-phenylethyl alcohol (floral smell, smell of rose petals) and isovaleric acid (smell of sweat, stuffy socks) were more sensitive for identifying hyposmia in patients with PD than three other odors. Multivariate logistic regression analysis showed that impaired visuospatial and executive function was associated with hyposmia (p=0.013), but was independent of other PD-associated variables.

Conclusion

Hyposmia was common in early, non-demented, drug-naïve PD patients. β-Phenylethyl alcohol and isovaleric acid were more superior for identifying hyposmia in early non-demented Chinese patients with PD. Hyposmia was associated with impaired visuospatial and executive function in patients with PD. Further prospective studies that apply a series of neuropsychological tests and functional magnetic resonance imaging methods in large samples in multicenter studies are needed to confirm our findings and to investigate the relationship between hyposmia and cognitive function with disease progression in patients with PD.

Attenuation of hyperalgesia responses via the modulation of 5-hydroxytryptamine signalings in the rostral ventromedial medulla and spinal cord in a 6-hydroxydopamine-induced rat model of Parkinson's disease

Background Although pain is one of the most distressing non-motor symptoms among patients with Parkinson's disease, the underlying mechanisms of pain in Parkinson's disease remain elusive. The aim of the present study was to investigate the role of serotonin (5-hydroxytryptamine) in the rostral ventromedial medulla (RVM) and spinal cord in pain sensory abnormalities in a 6-hydroxydopamine-treated rat model of Parkinson's disease. Methods The rotarod test was used to evaluate motor function. The radiant heat test and von Frey test were conducted to evaluate thermal and mechanical pain thresholds, respectively. Immunofluorescence was used to examine 5-hydroxytryptamine neurons and fibers in the rostral ventromedial medulla and spinal cord. High-performance liquid chromatography was used to determine 5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels. Results The duration of running time on the rotarod test was significantly reduced in 6-hydroxydopamine-treated rats. Nociceptive thresholds of both mechanical and heat pain were reduced compared to sham-treated rats. In addition to the degeneration of cell bodies and fibers in the substantia nigra pars compacta, the number of rostral ventromedial medulla 5-hydroxytryptamine neurons and 5-hydroxytryptamine fibers in the spinal dorsal horn was dramatically decreased. 5-Hydroxytryptamine concentrations in both the rostral ventromedial medulla and spinal cord were reduced. Furthermore, the administration of citalopram significantly attenuated pain hypersensitivity. Interestingly, Intra-rostral ventromedial medulla (intra-RVM) microinjection of 5,7-dihydroxytryptamine partially reversed pain hypersensitivity of 6-hydroxydopamine-treated rats. Conclusions These results suggest that the decreased 5-hydroxytryptamine contents in the rostral ventromedial medulla and spinal dorsal horn may be involved in hyperalgesia in the 6-hydroxydopamine-induced rat model of Parkinson's disease.

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 found 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, 13.06]%, 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, 20.41]%, 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 (β = 0.552, P < 0.001) and RBD (β = 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.

[Effect of obstructive sleep apnea on sleep architecture of acute ischemic stroke patients]

Objective: To investigate the effect of obstructive sleep apnea (OSA) on sleep architecture in acute ischemic stroke (AIS) patients. Methods: Seventy AIS patients with polysomnography examination from June 2014 to April 2016 were included in the Second Affiliated Hospital of Soochow University. Twenty-seven healthy controls during the same period were chosen as control group. According to apnea-hypopnea index (AHI), AIS patients were divided into AIS group (AHI<5/h) and AIS+ OSA group (AHI≥5/h). Their general conditions, Neurological function defect (national institutes of health stroke scale, NIHSS) on admission and at discharge and self-care ability (modified Rankin Scale, mRS) at discharge and 3 months later (mRS score <2 reflected good prognosis, and mRS score≥2 reflected unfavorable prognosis) were collected. Results: Fifty-two patients (74.3%) had OSA in total seventy AIS patients. Total sleep time (TST) was significantly shorter and sleep efficiency (SE) was lower in AIS group than the control group (P=0.007, 0.008, respectively). AIS+ OSA group had longer non-rapid eye movement (NREM)1 than control group [24.9(21.3) vs 14.3(10.6), P=0.044]. Compared with AIS group, AIS+ OSA group had shorter NREM3 [13.0(13.2) vs 19.6(12.8), P=0.039]. There was no significant difference between the infarct location of AIS group and AIS+ OSA group. However, AIS+ OSA group had higher mRS score observed at 3 months through follow-up visit than AIS group (P=0.027). Spearman correlation analysis showed a positive correlation between unfavorable prognosis of stroke at 3 months and atrial fibrillation, the oxygen desaturation index (ODI), percentage of oxygen saturation <90% of total recording time (TS90%), AHI, the longest time of apnea and hypopnea, respiratory related microarousal and NIHSS, while a negative correlation between unfavorable prognosis of stroke and NREM3, lowest nocturnal oxygen saturation (L-SaO(2)). On Logistic analysis, the unfavorable prognosis was independently predicted by AHI and NIHSS. Conclusions: Sleep architecture of cerebral infarction patients are disturbed with its characteristic of shorter total sleep time and lower sleep efficiency. Cerebral infarction patients with OSA have longer NREM1 and shorter NREM3.