Taijun Yunoki

Rivaroxaban and Apixaban Reduce Hemorrhagic Transformation After Thrombolysis by Protection of Neurovascular Unit in Rat

Background and Purpose— This study aimed to assess the risk and benefit of tissue-type plasminogen activator treatment after oral anticoagulation with rivaroxaban or apixaban compared with warfarin or placebo. Methods— Pretreatment with warfarin (0.2 mg/kg per day), rivaroxaban (2 mg/kg per day), apixaban (10 mg/kg per day), or vehicle (0.5% carboxymethyl cellulose sodium salt) was performed for 7 days. Transient middle cerebral artery occlusion was then induced for 120 minutes, followed by reperfusion with tissue-type plasminogen activator (10 mg/kg per 10 mL). Clinical parameters, including cerebral infarction volume, hemorrhagic volume, and blood coagulation, were examined. Twenty-four hours after reperfusion, markers for the neurovascular unit at the peri-ischemic lesion were immunohistochemically examined in brain sections, and matrix metalloproteinase-9 activity was measured by zymography. Results— The paraparesis score was significantly improved in the rivaroxaban-pretreated group compared with the warfarin-pretreated group. Intracerebral hemorrhage was observed in the warfarin-pretreated group, and this was reduced in the rivaroxaban and apixaban-pretreated groups compared with the vehicle group. Marked dissociation of astrocyte foot processes and the basal lamina or pericytes was observed in the warfarin-pretreated group, and this was improved in the rivaroxaban and apixaban-pretreated groups. Furthermore, activation of matrix metalloproteinase-9 in the ipsilateral warfarin-pretreated brain was greatly reduced in rivaroxaban- and apixaban-pretreated rats. Conclusions— This study shows a lower risk of intracerebral hemorrhage after tissue-type plasminogen activator treatment in rats with ischemic stroke that are pretreated with rivaroxaban and apixaban compared with pretreatment with warfarin. Reducing neurovascular dissociation by rivaroxaban and apixaban compared with warfarin could partly explain a reduction in hemorrhagic complications reported in clinical studies.

Modifying neurorepair and neuroregenerative factors with tPA and edaravone after transient middle cerebral artery occlusion in rat brain

Changes in expression of neurorepair and neuroregenerative factors were examined after transient cerebral ischemia in relation to the effects of tissue plasminogen activator (tPA) and the free radical scavenger edaravone. Physiological saline or edaravone was injected twice during 90 min of transient middle cerebral artery occlusion (tMCAO) in rats, followed by the same saline or tPA at reperfusion. Sizes of the infarct and protein factors relating to neurorepair and neuroregeneration were examined at 4d after tMCAO. The protein factors examined were: a chondroitin sulfate proteoglycan neurocan, semaphorin type 3A (Sema3A), a myelin-associated glycoprotein receptor (Nogo receptor, Nogo-R), a synaptic regenerative factor (growth associated protein-43, GAP43), and a chemotropic factor netrin receptor (deleted in colorectal cancer, DCC). Two groups treated by edaravone only or edaravone plus tPA showed a reduction in infarct volume compared to the two groups treated by vehicle only or vehicle plus tPA. Immunohistochemistry and western blot analyses indicated that protein expression of neurocan, Sema3A, Nogo-R, GAP43, and DCC was decreased with tPA, but recovered with edaravone. Additive edaravone prevented the reductions of these five proteins induced by tPA. The present study demonstrates for the first time that exogenous tPA reduced protein factors involved in inhibiting and promoting axonal growth, but that edaravone ameliorated such damage in brain repair after acute ischemia.

Computerized Touch-panel Screening Tests for Detecting Mild Cognitive Impairment and Alzheimer's Disease

OBJECTIVE The increasing population of elderly people in Japan has accelerated the demand for a simple screening test to detect cognitive and affective declines in mild cognitive impairment (MCI) and the early stage of dementia. Methods We compared the cognitive and affective functions, activities of daily living (ADLs) and the results of four computerized touch-panel screening tests in 41 MCI subjects, 124 patients with Alzheimers disease (AD) and 75 age- and gender-matched normal controls. RESULTS All computerized touch-panel games were successfully used to discriminate the AD patients from the normal controls (** p<0.01). Although there were no differences in the findings of the conventional cognitive assessments, the results of the flipping cards game were significantly different (** p<0.01) between the normal controls (19.3 ± 9.5 sec) and MCI subjects (30.9 ± 18.4 sec). Three conventional affective assessments, the ADL score, Abes behavioral and psychological symptoms of dementia (ABS) (** p<0.01) and the apathy scale (AS) (* p<0.05), could be used to discriminate the MCI subjects (ABS, 0.9 ± 1.5; AS, 12.8 ± 5.9) from the normal controls (ABS, 0.1 ± 0.4; AS, 8.9 ± 5.3). CONCLUSION In the present study, all four touch-panel screening tests could be employed to discriminate AD patients from normal controls, whereas only the flipping cards game was effective for distinguishing MCI subjects from normal controls. Therefore, this novel touch-panel screening test may be a more sensitive tool for detecting MCI subjects among elderly patients.

Reducing Hemorrhagic Complication by Dabigatran Via Neurovascular Protection After Recanalization With Tissue Plasminogen Activator in Ischemic Stroke of Rat

This study assesses the risks and benefits of tissue plasminogen activator (tPA) treatment under oral anticoagulation with dabigatran compared with warfarin or vehicle control in transient middle cerebral artery occlusion (tMCAO). After pretreatment with warfarin (0.2 mg/kg/day), dabigatran (20 mg/kg/day), or vehicle (0.5% carboxymethyl cellulose sodium salt) for 7 days, tMCAO was induced for 120 min, followed by reperfusion and tPA (10 mg/kg/10 ml). Clinical parameters, including cerebral infarction volume, hemorrhagic volume, and blood coagulation, were examined. At 24 hr after reperfusion, markers for the neurovascular unit at the peri‐ischemic lesion were immunohistochemically examined in brain sections, and MMP‐9 activity was measured by zymography. Paraparesis and intracerebral hemorrhage volume were significantly improved in the dabigatran‐pretreated group compared with the warfarin‐pretreated group. A marked dissociation between astrocyte foot processes and the basal lamina or pericyte was observed in the warfarin‐pretreated group, which was greatly improved in the dabigatran‐pretreated group. Furthermore, a remarkable activation of MMP‐9 in the ipsilateral warfarin‐pretreated rat brain was greatly reduced in dabigatran‐pretreated rats. The present study reveals that the mechanism of intracerebral hemorrhage with warfarin‐pretreatment plus tPA in ischemic stroke rats is the dissociation of the neurovascular unit, including the pericyte. Neurovascular protection by dabigatran, which was first shown in this study, could partially explain the reduction in hemorrhagic complication by dabigatran reported from clinical study.

Anti-oxidative nutrient rich diet protects against acute ischemic brain damage in rats

We evaluated the neuroprotective effects of an anti-oxidative nutrient rich enteral diet (AO diet) that contained rich polyphenols (catechins and proanthocyanidins) and many other anti-oxidative ingredients. Wistar rats were treated with either vehicle, normal AO diet (containing 100kcal/100mL, catechin 38.75mg/100mL and proanthocyanidin 19mg/100mL, 1mL/day), or high AO diet (containing 10 times the polyphenols of the normal AO diet) for 14 days, and were subjected to 90min of transient middle cerebral artery occlusion. The AO diet improved motor function, reduced cerebral infarction volume, and decreased both peroxidative markers such as 4-hydroxynonenal, advanced glycation end products, 8-hydroxy-2-deoxyguanosine and inflammatory markers such as monocyte chemotactic protein-1, ionized calcium-binding adapter molecule-1, and tumor necrosis factor-α. Our study has shown that an AO diet has neuroprotective effects through both anti-oxidative and anti-inflammatory mechanisms, indicating that nutritional control with polyphenols could be useful for patients with acute ischemic stroke.

Simultaneous assessment of cognitive and affective functions in multiple system atrophy and cortical cerebellar atrophy in relation to computerized touch-panel screening tests

Cognitive impairment and affective dysfunction of multiple system atrophy (MSA) and cortical cerebellar atrophy (CCA) have not been simultaneously examined comparing standard test batteries and a sensitive tool to detect subtle cognitive decline in patients. In the present study, we simultaneously examined cognitive and affective ability in MSA with predominant cerebellar ataxia (MSA-C, n=25), MSA with predominant parkinsonism (MSA-P, n=8), and CCA (n=14) patients using computerized touch panel screening tests. Mini-mental state examination (MMSE), Hasegawa dementia scale-revised (HDS-R), frontal assessment battery (FAB), and Montreal cognitive assessment (MoCA) scores were significantly lower in MSA-C patients than in age-and gender-matched normal controls. One MSA-C patient showed a decrease in the regional cerebral blood flow (rCBF) of the frontal lobe. MSA-P patients showed no such cognitive decline. Only FAB and MoCA scores were significantly lower in the CCA patients. MSA and CCA patients also showed a mild to moderate depressive state. Touch-panel screening tests demonstrated a significant decline of beating devils game in all three disease groups including MSA-P patients, and a significant extension of the flipping cards game only in MSA-C patients. The present study demonstrated different cognitive and affective functions among MSA-C, MSA-P, and CCA patients, and a sensitive screening method for cognitive assessment using touch-panel tests.

Pericyte protection by edaravone after tissue plasminogen activator treatment in rat cerebral ischemia.

Pericytes play a pivotal role in contraction, mediating inflammation and regulation of blood flow in the brain. In this study, changes of pericytes in the neurovascular unit (NVU) were examined in relation to the effects of exogenous tissue plasminogen activator (tPA) and a free radical scavenger, edaravone. Immunohistochemistry and Western blot analyses showed that the overlap between platelet‐derived growth factor receptor β‐positive pericytes and N‐acetylglucosamine oligomers (NAGO)‐positive endothelial cells increased significantly at 4 days after 90 min of transient middle cerebral artery occlusion (tMCAO). The number of pericytes and the overlap with NAGO decreased with tPA but recovered with edaravone 4 days after tMCAO with proliferation. Thus, tPA treatment damaged pericytes, resulting in the detachment from astrocytes and a decrease in glial cell line‐derived neurotrophic factor secretion. However, treatment with edaravone greatly improved tPA‐induced damage to pericytes. The present study demonstrates that exogenous tPA strongly damages pericytes and destroys the integrity of the NVU, but edaravone treatment can greatly ameliorate such damage after acute cerebral ischemia in rats.

Parkinsonism in Association with Dihydropteridine Reductase Deficiency

We report a 16-year-old man with disorders of tetrahydrobiopterin metabolism due to dihydropteridine reductase (DHPR) deficiency. He revealed moderate mental retardation, parkinsonism, and spastic paralysis with levodopa and 5-hydroxytryptophan (5-HTP) supplementation from the age of 2 months. Brain MRI showed high intensity areas in bilateral frontal and posterior deep white matter on fluid-attenuated inversion recovery (FLAIR). Coronal FLAIR image showed a high signal in bilateral pyramidal tracts. Single photon computed tomography (SPECT) imaging of the dopamine transporter was normal. This imaging indicates no dopaminergic cell loss. Our patient had no motor fluctuations or dyskinesias. Early diagnosis and replacement treatment might lead to a favorable outcome.

Fulminant case of neuromyelitis optica spectrum disorder initiated with area postrema symptoms

We report a 59‐year‐old man with intractable vomiting and hiccups, syndrome of inappropriate antidiuretic hormone secretion, quadriparesis, and encephalopathy of a short duration after the first episode as a result of neuromyelitis optica spectrum disorder. Magnetic resonance imaging showed high‐intensity areas in the hypothalamic, periventricular areas, and the presence of continuous lesions from the brainstem to the spinal cord. Intractable vomiting and hiccups should be considered as a hallmark of an exacerbation. Attentive consideration might be required, because the early initiation of treatment could prevent a subsequent neurological disorder.

Correlation of cerebral spinal fluid pH and HCO3- with disease progression in ALS

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal disease, which is characterized by progressive degeneration of spinal and bulbar innervating motor neurons. However, the underlying mechanisms of motor neuron death remain poorly understood. Several candidate disease biomarkers have been detected in cerebrospinal fluid of ALS patients. The present study analyzed various cerebral spinal fluid gas parameters in ALS patients and compared these values to controls, as well as patients with cervical spondylosis, Parkinson syndrome, and spinocerebellar degeneration. Cerebral spinal fluid pH positively correlated with the ALS functional rating scale in total and limb-type ALS patients. In addition, cerebral spinal fluid pH positively correlated with shorter disease duration (less than 22 weeks). These results suggested that cerebral spinal fluid pH provides a biomarker for ALS and could reflect mechanisms of disease progression in ALS patients.