Alzheimer's disease (AD) is a slowly progressive form of dementia, characterized by memory impairment and cognitive dysfunction. AD is mainly characterized by the deposition of amyloid β (Aβ) plaques and intracellular neurofibrillary tangles in the brain, along with neuronal degeneration and high levels of oxidative stress. Cilostazol (CSZ) was recently found to suppress the progression of cognitive decline in patients with stable AD receiving acetylcholinesterase inhibitors. This present study aimed to clarify the mechanism by which CSZ protects neurons from degeneration associated with Aβ(1-42). We used Aβ(1-42) to induce neurotoxicity in human neuroblastoma SH-SY5Y cells. Cells were pretreated with CSZ before co-treatment with Aβ. To evaluate the effect of CSZ on oxidative stress, we examined levels of reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate oxidase (Nox) activity, mRNA expression of NOX4, and Cu/Zn-Superoxide Dismutase (SOD), as well as apoptosis biomarkers [MTT, (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), caspase-3 and -9 activities and staining of annexin V]. We also assayed the activity of mitogen-activated protein kinases (MAPK): p38 MAPK and extracellular signal-regulated kinase1/2 (ERK1/2), and biomarkers of mitochondrial function (Bcl-2 and Bax), and cyclic adenosine monophosphate response element-binding protein (CREB). Aβ-induced oxidative stress (ROS, NOX4 activity, and expression of NOX mRNA), caspase activation (caspase-3 and -9), and p38 MAPK phosphorylation were suppressed by co-treatment with CSZ, but not by ERK1/2 activation. In addition, pretreatment with CSZ suppressed Aβ-induced apoptosis and increased cell viability via suppression of Bax (a proapoptotic protein), upregulation of Bcl-2 (an antiapoptotic protein) and Cu/Zn-SOD (a superoxide scavenging enzyme), and phosphorylation of CREB.Abbreviations: Aβ, amyloid β; AD, Alzheimer's disease; AMPK, AMP-activated protein kinase; APP, β-amyloid precursor protein; ASK, apoptosis signal-regulating kinase; ATRA, all-trans-retinoic acid; CREB, cyclic adenosine monophosphate response element-binding protein; CSZ, cilostazol; DTT, dithiothreitol; EDTA, ethylenediaminetetraacetic acid; ERK, extracellular signal-regulated kinase; FBS, Fetal bovine serum; HRP, Horseradish Peroxidase; JNK, c-jun N-terminal kinase; MAPK, mitogen-activated protein kinases; MCI, mild cognitive impairment; MEK, MAPK/ERK kinase; MKK, mitogen activated kinase kinase; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NADPH, nicotinamide adenine dinucleotide phosphate; NOX, nicotinamide adenine dinucleotide phosphate oxidase; PBS, phosphate-buffered saline; PCR, polymerase chain reaction; PDE, phosphodiesterase; RLU, relative light units; ROS, reactive oxygen species; SOD, Superoxide dismutase; TMB, 3,3 ,5,5 -tetramethylbenzidine. These findings suggested that CSZ could counteract neurotoxicity through multiple mechanisms, one mechanism involving the attenuation of oxidative stress by suppressing NOX activ...
BackgroundEffects of dopaminergic medication on executive function in patients with Parkinson’s disease (PD) are inconsistent.ObjectiveWe examined the effect of dopaminergic medication on executive function in 24 drug-naïve PD patients (de novo group) and in 21 PD patients on chronic dopaminergic medication (chronic medication group).MethodsPD patients without dementia were included in this study. For the de novo group patients, dopaminergic medication was initiated, and the dose was increased to improve motor symptoms. For the chronic medication group patients, dopaminergic medication was adjusted to relieve clinical problems. All participants were tested prior to and at 4–7 months after the drug initiation/adjustment. Executive function was assessed by using the Behavioral Assessment of the Dysexecutive Syndrome (BADS). Motor function was assessed by using the Unified Parkinson’s Disease Rating Scale (UPDRS; part III). Improvement in executive function was compared with a simultaneous change in levodopa equivalent doses (LED) of dopaminergic medication and with improvement in motor functions.ResultsThe mean standardized BADS scores showed no significant improvement in both the groups. In the de novo group, percent improvement in the standardized BADS scores showed a significant positive correlation with the LED, but not with percent improvement in UPDRS part III. In the chronic medication group, percent improvement in the standardized BADS scores was negatively correlated with change in the LED, but not with percent improvement in UPDRS part III. Multiple regression analysis using improvement in the standardized BADS score as a dependent variable and patient’s background factors (ie, age, education, disease duration, and motor and executive assessments at baseline) as independent variable showed that improvement in the executive assessment is significantly correlated with the LED only in the de novo group.ConclusionEffects of dopaminergic drug adjustment on executive function differ according to the patient’s clinical stage and depend on LED in de novo stage.
Background In patients with Parkinson's disease, executive deficits are known to correlate with motor dysfunctions, such as gait and postural instability. However executive deficits are sometimes difficult to detect using common frontal assessment batteries. Behavioral Assessment of Dysexecutive Syndrome includes six subtests to evaluate different aspects of executive function required in daily life. Among these the Modified Six Elements Test examines higher levels of executive function with regard to prospective memory and organization of behavior. Aim Using Behavioral Assessment of Dysexecutive Syndrome we examined which types of executive dysfunction correlate with motor symptoms in Parkinson's disease without apparent dementia. Methods A total of 54 Parkinson's disease patients with Mini‐Mental State Examination scores over 24 were assessed with the Unified Parkinson's Disease Rating Scale (total score of parts II and III as general motor function, subscores of tremor, rigidity, bradykinesia, gait disturbance and postural instability) for motor assessment, and both the Behavioral Assessment of Dysexecutive Syndrome (total raw score of all subtests and subscores of each of the 6 subtests) and Frontal Assessment Battery for executive function. Correlation coefficients for executive and motor assessments were compared. Results Among the Behavioral Assessment of Dysexecutive Syndrome subtests, the Modified Six Elements Test showed the strongest correlation with the Unified Parkinson's Disease Rating Scale subscore of gait disturbance, but did not correlate with patient background factors, such as age. Conclusion Even in Parkinson's disease without apparent dementia, deficits in complex executive functions, such as prospective memory and organization of behavior, correlate with motor dysfunctions, especially gait. We believe the Modified Six Elements Test is useful to evaluate early executive deficits.
Diagonistic apraxia is a corpus callosal disconnection syndrome. Callosal lesions in Neuromyelitis optica spectrum disorder (NMOSD) have been reported, but callosal disconnection syndrome are rare. A 48-year-old woman was treated for fever and a cough before hospitalization. Her fever abated immediately, but she had balance problems in walking and standing. She also had slurred speech. On neurological examination, she had diagonistic apraxia. Her left hand moved in an uncoordinated way when she moved her right hand: changing her clothes for example or using a knife and fork. She had to instruct her left hand to stop. She had dysarthria and her gait was wide-based. She also had many callosal disconnection syndrome symptoms such as alexia of left visual field, left ear extinction, crossed optic ataxia. Using FLAIR and DWI MRI, a mixture of low and high signals, a so-called “marbled pattern,” was seen in the corpus callosum. Since the patient was positive for anti-aquaporin-4 antibody, she was diagnosed with NMOSD. After two courses of steroid pulse therapy, the symptoms improved. Here we report diagonistic apraxia and other symptoms of callosal disconnection syndrome in anti-AQP4-positive NMOSD.
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