Time-dependent alterations of peripheral immune parameters after nigrostriatal dopamine depletion in a rat model of Parkinson’s disease

Dysfunction of the central dopaminergic system is associated with neurodegenerative disorders and mental illnesses such as Parkinson’s disease and schizophrenia. Patients suffering from these diseases were reported to exhibit altered immune functions compared to healthy subjects and imbalance of the central dopaminergic system has been suggested as one causative factor for the immune disturbances. However, it is unclear whether the observed immune changes are primary or secondary to the disease. Here we demonstrate that central dopamine (DA) depletion in a rat model of Parkinson’s disease induced transient changes in blood leukocyte distribution and cytokine production that were apparent until four weeks after bilateral intrastriatal administration of the neurotoxin 6-hydroxydopamine (6-OHDA). Eight weeks after treatment, no differences in blood immune parameters were anymore evident between neurotoxin-treated and control animals. Nevertheless, animals with a widespread damage of dopaminergic neurons in the nigrostriatal system showed an exacerbated pro-inflammatory response following in vivo challenge with bacterial lipopolysaccharide. Our data indicate that peripheral immune perturbations in the early phase after intrastriatal 6-OHDA administration might have been related to the neurodegenerative process itself whereas the increased sensitivity to the inflammatory stimulus seems to have resulted from an impaired dopaminergic control of prolactin (PRL) and corticosterone (CORT) secretion. The findings demonstrate that the brain dopaminergic system is involved in peripheral immune regulation and suggest that central dopaminergic hypoactivity bears the risk of excessive inflammation, e.g., during infection or tissue injury.     

Cerebral microbleeds in patients with Parkinson’s disease

Cerebral microbleeds (CMBs) are known to be associated with cognitive impairments in the elderly and in patients with various diseases; however, the nature of this association has not yet been evaluated in Parkinson’s disease (PD). In the present study, we analyzed the incidence of CMBs in PD according to cognitive status, and the impact of CMBs on cognitive performance was also evaluated. The CMBs in PD with dementia (n = 36), mild cognitive impairment (MCI, n = 46), or cognitively normal (n = 41) were analyzed using conventional T2*-weighted gradient-recalled echo images. Additionally, the relationship between the presence of CMBs and cognitive performance on individual tests of cognitive subdomains was analyzed using a detailed neuropsychological test. CMBs occurred more frequently in PD patients with dementia (36.1 %) compared to those with MCI (15.2 %), those who are cognitively normal (14.6 %), and normal controls (12.2 %, p = 0.025). However, the significant association of CMBs with PD dementia disappeared after adjusting white matter hyperintensities (WMHs) as a covariate. The frequencies of deep, lobar, and infratentorial CMBs did not differ among the four groups. After adjusting for age, sex, years of education, and WMHs, PD patients with CMBs had poorer performance in attention domain compared with those without CMBs (34.9 vs 42.6, p = 0.018). The present data demonstrate that even though CMBs were inseparably associated with the presence of WMHs, CMBs occur more commonly in PD patients with dementia than in those without dementia. Additionally, the burden of CMBs may contribute to further cognitive impairment in PD.     

Management of punding in Parkinson’s disease: an open-label prospective study

Punding, a peculiar stereotyped behavior characterized by intense fascination with complex, excessive, non-goal-oriented, repetitive activities, is a quite rare condition complicating Parkinson’s disease (PD). It is triggered by dopaminergic therapy and could have a strong impact on patient quality of life. No study has specifically investigated medical management of this condition, and only a few anecdotal reports have provided therapeutic hints. Given the suggested similarities to drug-induced dyskinesias, we have previously suggested a multistep algorithm for management of punding. We conducted a prospective open-label study on ten PD punders aimed at testing its validity. In two cases, reduction of levodopa therapy was efficacious; amantadine was effective in controlling punding in four cases; in the remaining cases, quetiapine was employed, with mild efficacy in two cases.     

Anchanling reduces pathology in a lactacystin-induced Parkinson’s disease model

A rat model of Parkinson’s disease was induced by injecting lactacystin stereotaxically into the left mesencephalic ventral tegmental area and substantia nigra pars compacta. After rats were intragastrically perfused with Anchanling, a Chinese medicine, mainly composed of magnolol, for 5 weeks, when compared with Parkinson’s disease model rats, tyrosine hydroxylase expression was increased, α-synuclein and ubiquitin expression was decreased, substantia nigra cell apoptosis was reduced, and apomorphine-induced rotational behavior was improved. Results suggested that Anchanling can ameliorate Parkinson’s disease pathology possibly by enhancing degradation activity of the ubiquitin-proteasome system.     

Structural and functional alterations of the heart in Parkinson’s disease

Parkinson’s disease (PD) patients have most frequently heart failure. The cause of this increased prevalence is not known. We designed a study to assess the cardiac function and cardiac structure in patients with PD compared to a control group.

Methods: Cross-sectional study with 50 PD patients and 50 healthy matched controls. We performed electro and echocardiograms to all patients and controls. The measurements were blind. In addition, we performed a neurological assessment.

Results: PD patients had higher left ventricular mass index (114.2 ± 38.4 vs. 94.1 ± 26.4 g/m²; P = 0.003) and higher left atrial volume (30.1 ± 7.9 vs. 26.7 ± 6.2 ml/m²; P = 0.01). PD was an independent risk factor for elevated left ventricular filling pressures (OR = 2.7, CI 95% 2.2–6.3; P = 0.004). Concentric remodeling and left ventricular hypertrophy were associated with more advanced Hoehn and Yahr stages. Moreover, patients with more dysautonomia symptoms showed more left ventricular hypertrophy. Finally, PD group had longer QT interval than control group regardless of the drugs.

Conclusions: PD is significantly associated with increased concentric left ventricular hypertrophy and diastolic dysfunction. Advanced stages of PD are associated with a more severe cardiac affection. These findings can explain the increase of heart failure in PD patients. Cardiomyopathy could be a non-motor parkinsonian symptom.     

Aminochrome as a preclinical experimental model to study degeneration of dopaminergic neurons in Parkinson’s disease

Four decades after L-dopa introduction to PD therapy, the cause of Parkinson's disease (PD) remains unknown despite the intensive research and the discovery of a number of gene mutations and deletions in the pathogenesis of familial PD. Different model neurotoxins have been used as preclinical experimental models to study the neurodegenerative process in PD, such as 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and rotenone. The lack of success in identifying the molecular mechanism for the degenerative process in PD opens the question whether the current preclinical experimental models are suitable to understand the degeneration of neuromelanin-containing dopaminergic neurons in PD. We propose aminochrome as a model neurotoxin to study the neurodegenerative processes occurring in neuromelanin-containing dopaminergic neurons in PD. Aminochrome is an endogenous compound formed during dopamine oxidation and it is the precursor of neuromelanin, a substance whose formation is a normal process in mesencephalic dopaminergic neurons. However, aminochrome itself can induce neurotoxicity under certain aberrant conditions such as (i) one-electron reduction of aminochrome catalyzed by flavoenzymes to leukoaminochrome o-semiquinone radical, which is a highly reactive neurotoxin; or (ii) the formation of aminochrome adducts with alpha-synuclein, enhancing and stabilizing the formation of neurotoxic protofibrils. These two neurotoxic pathways of aminochrome are prevented by DT-diaphorase, an enzyme that effectively reduces aminochrome with two-electrons preventing both aminochrome one-electron reduction or formation alpha synuclein protofibrils. We propose to use aminochrome as a preclinical experimental model to study the neurodegenerative process of neuromelanin containing dopaminergic neurons in PD.     

Mitochondrial dysfunction – a pathogenetic factor in Parkinson’s disease

The cause of Parkinson’s disease is still unknown. Nonetheless, there are some generally accepted hypotheses with respect to the cascade of dopaminergic cell degeneration. One of the factors is a decrease in respiratory chain complex I activity. This enzyme abnormality is only found in substantia nigra pars compacta. It is not currently known whether this is due to a genetic abnormality of the nuclear or mitochondrial genome or to an exo- or endotoxin. To date, no specific abnormality of the mitochondrial genome has been detected, although ageing leads to deletions in up to 5% of all mitochondrial genome molecules in the brain. There is controversy whether this complex I defect is also detectable in muscle or blood cells. It is our conviction that the considerable overlap between blood cells from normal controls and patients with Parkinson’s disease means that such measurements are not distinctive for the two conditions. A decrease in complex I activity in post-mitotic cells may be one of the crucial factors for cell death.

     

Neurofunctional correlates of attention rehabilitation in Parkinson’s disease: an explorative study

The effectiveness of cognitive rehabilitation (CR) in Parkinson’s disease (PD) is in its relative infancy, and nowadays there is insufficient information to support evidence-based clinical protocols. This study is aimed at testing a validated therapeutic strategy characterized by intensive computer-based attention-training program tailored to attention deficits. We further investigated the presence of synaptic plasticity by means of functional magnetic resonance imaging (fMRI). Using a randomized controlled study, we enrolled eight PD patients who underwent a CR program (Experimental group) and seven clinically/demographically-matched PD patients who underwent a placebo intervention (Control group). Brain activity was assessed using an 8-min resting state (RS) fMRI acquisition. Independent component analysis and statistical parametric mapping were used to assess the effect of CR on brain function. Significant effects were detected both at a phenotypic and at an intermediate phenotypic level. After CR, the Experimental group, in comparison with the Control group, showed a specific enhanced performance in cognitive performance as assessed by the SDMT and digit span forward. RS fMRI analysis for all networks revealed two significant groups (Experimental vs Control) × time (T0 vs T1) interaction effects on the analysis of the attention (superior parietal cortex) and central executive neural networks (dorsolateral prefrontal cortex). We demonstrated that intensive CR tailored for the impaired abilities impacts neural plasticity and improves some aspects of cognitive deficits of PD patients. The reported neurophysiological and behavioural effects corroborate the benefits of our therapeutic approach, which might have a reliable application in clinical management of cognitive deficits.     

Non-motor symptoms in Huntington’s disease: a comparative study with Parkinson’s disease

Journal of Neurology - The presence of non-motor symptoms in Huntington’s disease (HD) has not been systematically assessed so far. Our objective was to know their prevalence and to compare...     

Downregulation of Pael-R expression in a Parkinson’s disease cell model reduces apoptosis

The pathogenesis of Parkinson’s disease (PD), a common neurodegenerative disease, is poorly understood. Pael-R is a substrate of the Parkin protein, dysfunction of which can cause Pael-R protein accumulation, leading to cytotoxicity and dopaminergic neuronal apoptosis, causes of PD. In the present study, we induced PC12 cells to become dopaminergic neuron-like cells, and then suppressed Parkin expression in these cells to establish a PD cell model. We found that downregulating Pael-R gene expression in these PD model cells via RNA interference resulted in a reduction in the apoptotic rate. We conclude that downregulation of Pael-R gene expression is an effective approach for ameliorating the neuronal apoptosis caused by Parkin gene dysfunction.     

Cerebral amyloid angiopathy in streptozotocin rat model of sporadic Alzheimer’s disease: a long-term follow up study

Cerebral amyloid angiopathy is manifested as accumulation of amyloid β (Aβ) peptide in the wall of meningeal and cerebral arteries, arterioles and capillaries and is frequently found postmortem in sporadic Alzheimer’s disease (sAD) patients. It is difficult to assess when and how cerebral amyloid angiopathy develops and progresses in humans in vivo, which is why animal AD models are used. Streptozotocin-intracerebroventricularly (STZ-icv) treated rats have been recently proposed as the model of sAD which develops insulin resistant brain state preceding Aβ pathology development. Vascular Aβ deposits in the brain of STZ-icv-treated rats (3 months old at the time of icv treatment) were visualized by Thioflavine-S staining, Congo red staining and Aβ immunohistochemistry. Thioflavine-S and Congo red staining revealed diffuse congophilic deposits in the wall of meningeal and cortical blood vessels both 6 and 9 months after the STZ-icv treatment. Preliminary Aβ1-42 and Aβ1-16 immunohistochemistry experiments showed positive staining in blood vessels 3 and 9 months after the STZ-icv treatment, respectively. Results suggest that cerebral amyloid angiopathy observed 6 and 9 months after the STZ-icv treatment seems to be a continuation and progression of the amyloid pathology observed already 3 months following the STZ-icv treatment in this non-transgenic sAD animal model.     

Astrocyte reactivity in related brain regions in a mouse model of MPTP-induced Parkinson’s disease

BACKGROUND： Severe injury to dopaminergic neuronal cell bodies and their axon terminals in the substantia nigra pars compacta （SNC） has been observed in both Parkinson＇s disease （PD） patients or in 1-methy-4-phenyl-1,2,3,6-tetrahydropyrindine（MPTP）-induced PD animal models, but only slight injury occurs in the adjacent ventral tegmentat area （VTA）. The mechanisms underlying this selective injury remain poorly understood. OBJECTIVE： To comparatively observe astrocyte reactivity in the SNC, caudate putamen （CPu）, VTA, and frontal association cortex （FrA）.
DESIGN, TIME AND SETTING： A cellular and molecular biology, randomized, controlled experiment was performed at the Institute of Neurobiology, Department of Human Anatomy, Medical School of Nantong University, between December 2006 and September 2008.
MATERIALS： A total of 80 healthy adult male C57BL/6 mice were included in this study. MPTP was purchased from Sigma, USA.
METHODS： Mice were randomly divided into a model group （n = 64） and a sham-operated group （n = 16）. PD was induced in the mice from the model group by intraperitoneal injection of 20 mg/kg MPTP, once every three hours, for a total of 4 times.
MAIN OUTCOME MEASURES： Tyrosine hydroxylase （TH）-immunoreactive neurons and glial fibrillary acidic protein （GFAP）-immunoreactive astrocytes were examined by dual immunofluorescence labeling. GFAP-immunoreactive astrocytes in the CPu and FrA were determined by immunofluorescent staining. GFAP mRNA expression in the SNC, CPu, VTA, and FrA was detected using real-time polymerase chain reaction. TH protein levels in the TH-immunoreactive axon terminals of the CPu and FrA were detected by Western blotting.
RESULTS： Numbers of TH-immunoreactive neurons in the SNC, and TH protein level in the CPu, markedly decreased （by approximately 68%） 1 day after MPTP injection, and gradually increased at 3 days. Simultaneously, astrocyte reactivity was strengthened, in particular at 7 days. However, after MPTP injection, decreases in the numbers of TH-immunoreactive neurons in the VTA, and TH protein levels in the FrA, were less apparent （approximately 15%）. Also, no obvious astrocyte reactivity was observed.
CONCLUSION： In a mouse model of PD, astrocyte reactivity was apparent in the SNC and CPu, but not the VTA or FrA. In addition, astrocyte reactivity was greater in regions where injury to dopaminergic neurons was more severe.     

Hallucinations in Parkinson’s disease: cross-sectional study

The aim of this study was to estimate the prevalence and risk factors for the development of hallucinations in patients with Parkinson's disease (PD). This cross-sectional study included 180 consecutive, non-demented patients with PD. Out of them, 24 patients (13%) experienced some kind of hallucinations. Visual hallucinations were present in 22/24 (90%) subjects. Univariate logistic regression analysis has shown relationship between presence of hallucinations and the following variables: age of patients (p?=?0.025), PD duration (p?=?0.001), duration of levodopa treatment (p?=?0.001), total daily dose of levodopa (p?=?0.033), presence of levodopa-induced dyskinesia (p?=?0.002) and their duration (p?=?0.021), and experience of nightmares (p?=?0.042). Hallucinations were also associated with higher scores of the UPDRS (p?=?0.001), HDRS (p?=?0.001) and the NPI total score (p?=?0.001), and higher H-Y stages of the disease (p?=?0.001). Multivariate regression analysis has demonstrated that the duration of PD (p?=?0.024) as well as NPI total score (p?=?0.002) was significant independent risk factors for hallucinations in PD.     

Progressive changes of orexin system in a rat model of 6-hydroxydopamineinduced Parkinson’s disease

Objective

Sleep disturbance, which is characterized by excessive daytime sleepiness and sleep attacks, is frequently observed in patients with Parkinson’s disease (PD). Loss of orexin neurons in hypothalamus and the resultant decreased level of orexin in cerebrospinal fluid (CSF) found in narcolepsy patients may also play an essential role in the pathogenesis of sleep disturbance. The present study aimed to investigate the possible changes in the orexin system during PD progression.

Methods

After the establishment of a rat PD model by injecting 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, the numbers of orexin-A- and tyrosine hydroxylase (TH)-positive neurons, and the levels of orexin-A fibers and orexin-A in CSF were examined by immunohistochemistry and ELISA assay, respectively.

Results

Compared to the TH-containing neurons that exhibited fast degeneration in response to 6-OHDA, orexin-A-containing neurons were less sensitive to 6-OHDA. The number of orexin-A-positive neurons began to decrease at day 21 after operation, and at day 49, it decreased by 30% of the initial level. The orexin-A level in CSF of PD rats did not show any obvious fluctuations compared to the control, and there was no obvious reduction in the density of orexin-A-positive fibers in brain areas such as tuberomammillary nucleus.

Conclusion

These results reveal for the first time the dynamic changes of orexin system during the progression of PD. This may provide valuable information for drug development to reverse the loss of orexin neurons and sleep disturbance in PD patients.     

A comprehensive model of health-related quality of life in Parkinson’s disease

BACKGROUND : Insight in how impairments and disabilities related to Parkinson's disease (PD) influence health-related quality of life (HRQoL) is required to review adequacy of current management strategies. METHODS : The Scales for Outcomes in Parkinson's disease (SCOPA) evaluation was used to assess impairments and disabilities. HRQoL was assessed with the EuroQol-5D Visual Analogue Scale. 378 patients with PD who participated in the SCOPA/PROPARK cohort were assessed while on their usual treatment. Multiple linear regression analysis and structural equation modelling were used to construct a model of factors that influence HRQoL. RESULTS : A model with good fit was constructed that identified various impairments and disabilities as important contributors to HRQoL in PD. Of the disabilities, psychosocial well-being had a larger impact on HRQoL than physical functioning. Of the impairments, depression had the largest contribution to HRQoL, followed by axial motor symptoms, gastrointestinal symptoms, and urinary symptoms. In addition, pain, psychiatric and motor complications, and daytime sleepiness had small but significant influences on HRQoL. CONCLUSION : Multiple factors, including disabilities, nonmotor symptoms and axial motor symptoms, affect HRQoL in patients with PD. In patients who are on symptomatic treatment aiming to alleviate mainly motor symptoms, there is a large impact on HRQoL of nonmotor and nondopaminergic symptoms. Research is warranted to develop and evaluate management strategies for the aspects that currently impact on HRQoL as psychosocial well-being, depressive symptoms, axial motor symptoms, gastrointestinal symptoms, and urinary symptoms. These findings call for a multidisciplinary approach in the care of these features.     

Rehabilitation of hypomimia in Parkinson’s disease: a feasibility study of two different approaches

Parkinson’s disease (PD) patients frequently have an impairment of facial expression both in voluntary and spontaneous emotional expression. Aim of this study was to evaluate the feasibility of a rehabilitation program for hypomimia in patients with PD, comparing two different approaches. Thirty-six patients with PD were included: 20 patients received a rehabilitative intervention for hypomimia either with a DVD showing exercises focused on facial muscles (PD-group-A) or with a therapist-guided facial rehabilitation with a proprioceptive/recognition approach (PD-group-B). Sixteen patients (PD-Ctrl group) did not receive any treatment and served as control group. The feasibility of the proposed rehabilitation techniques was the main focus of this evaluation. We also evaluate the efficacy of the treatments by means of the sub-item 19 of the Unified Parkinson’s disease Rating Scale motor score (UPDRS-III) and by a computerized analysis of facial expression (E-Motion), which was assessed prior to (T0) and after therapy (T1). The proposed rehabilitative program for the treatment of hypomimia was shown to be feasible. Our data show a significant improvement in UPDRS-III sub-item 19 in PD-group-B compared to PD-group-A, (p = 0.005) and to PD-Ctrl (p = 0.003) and in expressivity of fear in PD-group-B compared to PD-Ctrl (p = 0.01). The proposed rehabilitative program showed to be feasible. A larger multi-center trial is now warranted to establish its efficacy to improve facial expression over long time period.     

Profile of levodopa-induced dyskinesia in patients of Parkinson’s disease: a record based study

Abstract

Objectives:

Levodopa-induced dyskinesia (LID) is one of the most disabling complications of long-term pharmacotherapy of Parkinson’s disease (PD). The objective of our study was to examine the clinical profile and determinants of severity of LID in Indian PD patients on levodopa therapy.

Methods:

Retrospective analysis of records of PD patients with LID was performed. All patients were on levodopa and carbidopa combination. Records of subjects with complete information about disease profile, drug intake, and dyskinesia were analyzed. Characterization of LID was based on responses to part IV of unified Parkinson's disease rating scale (UPDRS).

Results:

Records of 42 patients (M∶F = 4·6∶1) were analyzed. The median Hoehn and Yahr (H&Y) stage was 2·5 while median duration of levodopa therapy was 6·16 years (range: 1·91–14·58). Early morning dystonia was reported by 97·6% of the patients. Patients treated with ≧2 concomitant PD medication reported a significantly lower median UPDRS IV A score compared to patients treated with <2 number of concomitant drugs. A trend toward a lower UPDRS IV A score was associated with use of dopamine agonists (DA). Patients with H&Y score ≧3 had a significantly higher median total UPDRS IV A score than patients with H&Y score <3.

Discussion:

Early morning dystonia might be more common among Indian patients of LID. Use of a higher number of concomitant PD medications alongside levodopa is associated with a reduced severity of dyskinesia, even on prolonged use. Levodopa-induced dyskinesia is not only a drug-related phenomenon but the stage of PD itself also affects the dyskinesia severity.     

Pisa syndrome in Parkinson’s disease: an electrophysiological and imaging study

The pathophysiology of postural abnormalities in patients with Parkinson’s disease is poorly understood. In the present study, 13 patients with Pisa syndrome (PS) underwent EMG study of paraspinal lumbar (L2–L4) and thoracic (T8–T10) muscles, and of non-paraspinal muscles. Patients also underwent a whole spine X-ray and an MRI assessment of paraspinal muscles (L1–S1). The EMG evaluation disclosed two main patterns: patients with pattern I (n = 6, hyperactivity of lumbar paraspinals ipsilateral to the trunk leaning side) or pattern II (n = 7: hyperactivity of lumbar paraspinals contralateral to the trunk leaning side. In pattern I, half the patients also had ipsilateral hyperactivity of the thoracic paraspinals, the other half had contralateral thoracic hyperactivity; in pattern II, thoracic paraspinal hyperactivity was contralateral in all patients (like the lumbar paraspinal hyperactivity). Non-paraspinal muscles were hyperactive ipsilaterally in four of six patients with pattern I and in all patients with pattern II. The MRI showed mild muscular atrophy with fatty degeneration in patients with pattern I, whereas in pattern II patients this was greater and prevalent on paraspinal lumbar muscles ipsilateral to the leaning side. The present data support the hypothesis that two main patterns of muscular activation are associated with PS. In both patterns, hyperactivity of contralateral paraspinal muscles is probably compensatory for the trunk leaning.