scholarly journals Dopaminergic but not Cholinergic Neurodegeneration is Correlated with Gait Disturbances in PINK1 Knockout Rats

2021 ◽  
Author(s):  
Valerie M DeAngelo ◽  
Justin D Hilliard ◽  
George C McConnell
Keyword(s):  
Neurodegenerative Disorder ◽  
Immunohistochemical Analysis ◽  
Cell Loss ◽  
Pedunculopontine Nucleus ◽  
Significant Loss ◽  
Substantia Nigra Pars Compacta ◽  
Multiple Parameters ◽  
Gait Dysfunction ◽  
Underlying Mechanisms ◽  
Gait Abnormalities

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by gait dysfunction in later stages of the disease. PD hallmarks include a decrease in stride length, run speed, and swing time; an increase in stride time, stance time, and base of support; dopaminergic degeneration in the basal ganglia; and cholinergic degeneration in the pedunculopontine nucleus (PPN). A progressive animal model of PD is needed to identify treatments for gait dysfunction. The goal of this study was to quantify progressive gait degeneration in PTEN-induced putative kinase 1 knockout (P1KO) rats and investigate neurodegeneration as potential underlying mechanisms. Gait analysis was performed in male P1KO and wild-type rats at 5 and 8 months of age and immunohistochemical analysis at 8 months. Multiple parameters of volitional gait were measured using a runway system. P1KO rats exhibited significant gait deficits at 5 months, but not 8 months. Gait abnormalities improved over time suggesting compensation during behavioral testing. At 8 months a 15% loss of tyrosine hydroxylase (TH) in the striatum, a 27% loss of TH-positive cells in the substantia nigra pars compacta, and no significant loss of choline acetyltransferase-positive cells in the PPN was found. Dopaminergic cell loss may contribute to gait deficits in the P1KO model, but not cholinergic cell loss. The P1KO rat with the greatest dopamine loss exhibited the most pronounced PD-like gait deficits, highlighting variability within the model. Further analysis is required to determine the suitability of the P1KO rat as a progressive model of gait abnormalities in PD.

HFE H63D Limits Nigral Vulnerability to Paraquat in Agricultural Workers

2021 ◽  
Vol 181 (1) ◽  
pp. 47-57
Author(s):  
Ernest W Wang ◽  
Max L Trojano ◽  
Mechelle M Lewis ◽  
Guangwei Du ◽  
Hairong Chen ◽  
...  
Keyword(s):  
Serum Iron ◽  
Neurodegenerative Disorder ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Substantia Nigra Pars Compacta ◽  
Transverse Relaxation Rate ◽  
Murine Homolog ◽  
High Prevalence ◽  
Underlying Mechanisms ◽  
Microstructural Integrity

Abstract Paraquat is an herbicide whose use is associated with Parkinson’s disease (PD), a neurodegenerative disorder marked by neuron loss in the substantia nigra pars compacta (SNc). We recently observed that the murine homolog to the human H63D variant of the homeostatic iron regulator (HFE) may decrease paraquat-associated nigral neurotoxicity in mice. The present study examined the potential influence of H63D on paraquat-associated neurotoxicity in humans. Twenty-eight paraquat-exposed workers were identified from exposure histories and compared with 41 unexposed controls. HFE genotypes, and serum iron and transferrin were measured from blood samples. MRI was used to assess the SNc transverse relaxation rate (R2*), a marker for iron, and diffusion tensor imaging scalars of fractional anisotropy (FA) and mean diffusivity, markers of microstructural integrity. Twenty-seven subjects (9 exposed and 18 controls) were H63D heterozygous. After adjusting for age and use of other PD-associated pesticides and solvents, serum iron and transferrin were higher in exposed H63D carriers than in unexposed carriers and HFE wildtypes. SNc R2* was lower in exposed H63D carriers than in unexposed carriers, whereas SNc FA was lower in exposed HFE wildtypes than in either unexposed HFE wildtypes or exposed H63D carriers. Serum iron and SNc FA measures correlated positively among exposed, but not unexposed, subjects. These data suggest that H63D heterozygosity is associated with lower neurotoxicity presumptively linked to paraquat. Future studies with larger cohorts are warranted to replicate these findings and examine potential underlying mechanisms, especially given the high prevalence of the H63D allele in humans.

scholarly journals Pesticides and Parkinson’s Disease

2001 ◽  
Vol 1 ◽  
pp. 207-208 ◽  
Author(s):  
Todd B. Sherer ◽  
Ranjita Betarbet ◽  
J. Timothy Greenamyre
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Substantia Nigra ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Lewy Bodies ◽  
Substantia Nigra Pars Compacta ◽  
Selective Death ◽  
Underlying Mechanisms ◽  
Common Neurodegenerative Disorder

Parkinson’s disease (PD), a common neurodegenerative disorder affects approximately 1% of the population over 65. PD is a late-onset progressive motor disease characterized by tremor, rigidity (stiffness), and bradykinesia (slowness of movement). The hallmark of PD is the selective death of dopamine-containing neurons in the substantia nigra pars compacta which send their projections to the striatum and the presence of cytoplasmic aggregates called Lewy bodies [1-2]. Most cases of PD are sporadic but rare cases are familial, with earlier onset. The underlying mechanisms and causes of PD still remain unclear.

scholarly journals A Multi-Scale Computational Model of Excitotoxic Loss of Dopaminergic Cells in Parkinson’s Disease

2020 ◽  
Author(s):  
Vignayanandam R. Muddapu ◽  
V. Srinivasa Chakravarthy
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cell Death ◽  
Computational Model ◽  
Neurodegenerative Disorder ◽  
Cell Loss ◽  
Therapeutic Interventions ◽  
Substantia Nigra Pars Compacta ◽  
Therapeutic Effects ◽  
Multi Scale

ABSTRACTParkinson’s disease (PD) is a neurodegenerative disorder caused by loss of dopaminergic neurons in Substantia Nigra pars compacta (SNc). Although the exact cause of the cell death is not clear, the hypothesis that metabolic deficiency is a key facor has been gaining attention in the recent years. In the present study, we investigate this hypothesis using a multi-scale computational model of the subsystem of the basal ganglia comprising Subthalamic Nucleus (STN), Globus Pallidus externa (GPe) and SNc. The model is a multiscale model in that interactions among the three nuclei are simulated using more abstract Izhikevich neuron models, while the molecular pathways involved in cell death of SNc neurons are simulated in terms of detailed chemical kinetics. Simulation results obtained from the proposed model showed that energy deficiencies occurring at cellular and network levels could precipitate the excitotoxic loss of SNc neurons in PD. At the subcellular level, the models show how calcium elevation leads to apoptosis of SNc neurons. The therapeutic effects of several neuroprotective interventions are also simulated in the model. From neuroprotective studies, it was clear that glutamate inhibition and apoptotic signal blocker therapies were able to halt the progression of SNc cell loss when compared to other therapeutic interventions, which only slows down the progression of SNc cell loss.

The Therapeutic Potential of Quercetin in Parkinson’s Disease: Insights into its Molecular and Cellular Regulation

2020 ◽  
Vol 21 (5) ◽  
pp. 509-518 ◽  
Author(s):  
Omid Reza Tamtaji ◽  
Tooba Hadinezhad ◽  
Maryam Fallah ◽  
Arash Rezaei Shahmirzadi ◽  
Mohsen Taghizadeh ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neurodegenerative Disorder ◽  
Therapeutic Potential ◽  
Substantia Nigra Pars Compacta ◽  
Cellular Regulation ◽  
Pathophysiological Role ◽  
Underlying Mechanisms ◽  
Treatment Procedures

Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disorder characterized by the progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNc). PD is a multifactorial disorder, with several different factors being suggested to play a synergistic pathophysiological role, including oxidative stress, autophagy, underlying pro-inflammatory events and neurotransmitters abnormalities. Overall, PD can be viewed as the product of a complex interaction of environmental factors acting on a given genetic background. The importance of this subject has gained more attention to discover novel therapies to prevent as well as treat PD. According to previous research, drugs used to treat PD have indicated significant limitations. Therefore, the role of flavonoids has been extensively studied in PD treatment. Quercetin, a plant flavonol from the flavonoid group, has been considered as a supplemental therapy for PD. Quercetin has pharmacological functions in PD by controlling different molecular pathways. Although few studies intended to evaluate the basis for the use of quercetin in the context of PD have been conducted so far, at present, there is very little evidence available addressing the underlying mechanisms of action. Various principal aspects of these treatment procedures remain unknown. Here, currently existing knowledge supporting the use of quercetin for the clinical management of PD has been reviewed.

scholarly journals Treatment Options for Motor and Non-Motor Symptoms of Parkinson’s Disease

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 612
Author(s):  
Frank C. Church
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neurodegenerative Disorder ◽  
Treatment Options ◽  
Neuronal Cell ◽  
Cell Loss ◽  
Management Program ◽  
Additional Treatment ◽  
Substantia Nigra Pars Compacta ◽  
Speech Pathology

Parkinson’s disease (PD) usually presents in older adults and typically has both motor and non-motor dysfunctions. PD is a progressive neurodegenerative disorder resulting from dopaminergic neuronal cell loss in the mid-brain substantia nigra pars compacta region. Outlined here is an integrative medicine and health strategy that highlights five treatment options for people with Parkinson’s (PwP): rehabilitate, therapy, restorative, maintenance, and surgery. Rehabilitating begins following the diagnosis and throughout any additional treatment processes, especially vis-à-vis consulting with physical, occupational, and/or speech pathology therapist(s). Therapy uses daily administration of either the dopamine precursor levodopa (with carbidopa) or a dopamine agonist, compounds that preserve residual dopamine, and other specific motor/non-motor-related compounds. Restorative uses strenuous aerobic exercise programs that can be neuroprotective. Maintenance uses complementary and alternative medicine substances that potentially support and protect the brain microenvironment. Finally, surgery, including deep brain stimulation, is pursued when PwP fail to respond positively to other treatment options. There is currently no cure for PD. In conclusion, the best strategy for treating PD is to hope to slow disorder progression and strive to achieve stability with neuroprotection. The ultimate goal of any management program is to improve the quality-of-life for a person with Parkinson’s disease.

scholarly journals Nicotinamide mononucleotide treatment increases NAD+ levels in an iPSC Model of Parkinson’s Disease but does not impact sirtuin activity

2020 ◽  
Author(s):  
Brett Fulleylove-Krause ◽  
Samantha Sison ◽  
Allison Ebert
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Stem Cell ◽  
Dopaminergic Neurons ◽  
Neurodegenerative Disorder ◽  
Nicotinamide Mononucleotide ◽  
Reduce Activity ◽  
Underlying Mechanisms ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Dopaminergic Neuron Loss

Abstract Objectives: Parkinson’s disease (PD) is a common neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra. Although the underlying mechanisms of dopaminergic neuron loss is not fully understood, evidence suggests mitochondrial malfunction as a key contributor to disease pathogenesis. We previously found that human PD patient stem cell-derived dopaminergic neurons exhibit reduced nicotinamide adenine dinucleotide (NAD+) levels and reduce activity of sirtuins, a group of NAD+-dependent deacetylase enzymes that participate in the regulation of mitochondrial function, energy production, and cell survival. Thus, here we tested whether treatment of PD stem cell-derived dopaminergic neurons with nicotinamide mononucleotide (NMN), an NAD+ precursor, could increase NAD+ levels and improve sirtuin activity. Results: We treated PD iPSC-derived dopaminergic neurons with NMN and found that NAD+ levels did increase. The deacetylase activity of sirtuin (SIRT) 2 was improved with NMN treatment, but NMN had no impact on deacetylase activity of SIRT 1 or 3. These results suggest that NMN can restore NAD+ levels and SIRT 2 activity, but that additional mechanisms are involved SIRT 1 and 3 dysregulation in PD dopaminergic neurons.

scholarly journals Potential Role of Caffeine in the Treatment of Parkinson’s Disease

2016 ◽  
Vol 10 (1) ◽  
pp. 42-58 ◽  
Author(s):  
Mohsin H.K. Roshan ◽  
Amos Tambo ◽  
Nikolai P. Pace
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Randomized Clinical Trials ◽  
Neurodegenerative Disorder ◽  
Lewy Bodies ◽  
Substantia Nigra Pars Compacta ◽  
Muscle Rigidity ◽  
Therapeutic Effects ◽  
Motor Symptoms ◽  
Wide Range

Parkinson’s disease [PD] is the second most common neurodegenerative disorder after Alzheimer’s disease, affecting 1% of the population over the age of 55. The underlying neuropathology seen in PD is characterised by progressive loss of dopaminergic neurons in the substantia nigra pars compacta with the presence of Lewy bodies. The Lewy bodies are composed of aggregates of α-synuclein. The motor manifestations of PD include a resting tremor, bradykinesia, and muscle rigidity. Currently there is no cure for PD and motor symptoms are treated with a number of drugs including levodopa [L-dopa]. These drugs do not delay progression of the disease and often provide only temporary relief. Their use is often accompanied by severe adverse effects. Emerging evidence from bothin vivoandin vitrostudies suggests that caffeine may reduce parkinsonian motor symptoms by antagonising the adenosine A2Areceptor, which is predominately expressed in the basal ganglia. It is hypothesised that caffeine may increase the excitatory activity in local areas by inhibiting the astrocytic inflammatory processes but evidence remains inconclusive. In addition, the co-administration of caffeine with currently available PD drugs helps to reduce drug tolerance, suggesting that caffeine may be used as an adjuvant in treating PD. In conclusion, caffeine may have a wide range of therapeutic effects which are yet to be explored, and therefore warrants further investigation in randomized clinical trials.

Parkinson's Disease Genetics and Pathophysiology

2021 ◽  
Vol 44 (1) ◽  
pp. 87-108
Author(s):  
Gabriel E. Vázquez-Vélez ◽  
Huda Y. Zoghbi
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Genetic Variants ◽  
Neurodegenerative Disorder ◽  
Disease Risk ◽  
Lewy Bodies ◽  
Substantia Nigra Pars Compacta ◽  
Disease Modifying ◽  
Common Neurodegenerative Disorder

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by degeneration of the substantia nigra pars compacta and by accumulation of α-synuclein in Lewy bodies. PD is caused by a combination of environmental factors and genetic variants. These variants range from highly penetrant Mendelian alleles to alleles that only modestly increase disease risk. Here, we review what is known about the genetics of PD. We also describe how PD genetics have solidified the role of endosomal, lysosomal, and mitochondrial dysfunction in PD pathophysiology. Finally, we highlight how all three pathways are affected by α-synuclein and how this knowledge may be harnessed for the development of disease-modifying therapeutics.

scholarly journals Palmitate and Stearate are Increased in the Plasma in a 6-OHDA Model of Parkinson’s Disease

Metabolites ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 31 ◽  
Author(s):  
Anuri Shah ◽  
Pei Han ◽  
Mung-Yee Wong ◽  
Raymond Chang ◽  
Cristina Legido-Quigley
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Stearic Acid ◽  
Palmitic Acid ◽  
Neurodegenerative Disorder ◽  
Motor Dysfunction ◽  
Substantia Nigra Pars Compacta ◽  
Control Group ◽  
Sprague Dawley ◽  
Curative Therapy

Introduction: Parkinson’s disease (PD) is the second most common neurodegenerative disorder, without any widely available curative therapy. Metabolomics is a powerful tool which can be used to identify unexpected pathway-related disease progression and pathophysiological mechanisms. In this study, metabolomics in brain, plasma and liver was investigated in an experimental PD model, to discover small molecules that are associated with dopaminergic cell loss. Methods: Sprague Dawley (SD) rats were injected unilaterally with 6-hydroxydopamine (6-OHDA) or saline for the vehicle control group into the medial forebrain bundle (MFB) to induce loss of dopaminergic neurons in the substantia nigra pars compacta. Plasma, midbrain and liver samples were collected for metabolic profiling. Multivariate and univariate analyses revealed metabolites that were altered in the PD group. Results: In plasma, palmitic acid (q = 3.72 × 10−2, FC = 1.81) and stearic acid (q = 3.84 × 10−2, FC = 2.15), were found to be increased in the PD group. Palmitic acid (q = 3.5 × 10−2) and stearic acid (q = 2.7 × 10−2) correlated with test scores indicative of motor dysfunction. Monopalmitin (q = 4.8 × 10−2, FC = −11.7), monostearin (q = 3.72 × 10−2, FC = −15.1) and myo-inositol (q = 3.81 × 10−2, FC = −3.32), were reduced in the midbrain. The liver did not have altered levels of these molecules. Conclusion: Our results show that saturated free fatty acids, their monoglycerides and myo-inositol metabolism in the midbrain and enteric circulation are associated with 6-OHDA-induced PD pathology.

scholarly journals Impact of Aging on the 6-OHDA-Induced Rat Model of Parkinson’s Disease

2020 ◽  
Vol 21 (10) ◽  
pp. 3459 ◽  
Author(s):  
Sandra Barata-Antunes ◽  
Fábio G. Teixeira ◽  
Bárbara Mendes-Pinheiro ◽  
Ana V. Domingues ◽  
Helena Vilaça-Faria ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Animal Welfare ◽  
Neurodegenerative Disorder ◽  
Negative Impact ◽  
Substantia Nigra Pars Compacta ◽  
Nigrostriatal Pathway ◽  
Aged Rats ◽  
Age Related ◽  
The Impact

Parkinson’s disease (PD) is the second most common age-related neurodegenerative disorder. The neurodegeneration leading to incapacitating motor abnormalities mainly occurs in the nigrostriatal pathway due to the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Several animal models have been developed not only to better understand the mechanisms underlying neurodegeneration but also to test the potential of emerging disease-modifying therapies. However, despite aging being the main risk factor for developing idiopathic PD, most of the studies do not use aged animals. Therefore, this study aimed at assessing the effect of aging in the unilateral 6-hydroxydopamine (6-OHDA)-induced animal model of PD. For this, female young adult and aged rats received a unilateral injection of 6-OHDA into the medial forebrain bundle. Subsequently, the impact of aging on 6-OHDA-induced effects on animal welfare, motor performance, and nigrostriatal integrity were assessed. The results showed that aging had a negative impact on animal welfare after surgery. Furthermore, 6-OHDA-induced impairments on skilled motor function were significantly higher in aged rats when compared with their younger counterparts. Nigrostriatal histological analysis further revealed an increased 6-OHDA-induced dopaminergic cell loss in the SNpc of aged animals when compared to young animals. Overall, our results demonstrate a higher susceptibility of aged animals to 6-OHDA toxic insult.

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