Reactive oxygen species (ROS) are major exacerbation factor in acute ischemic stroke, and thrombolytic agent tissue plasminogen activator (tPA) may worsen motor function and cerebral infarcts. The platinum nanoparticle (nPt) is a novel ROS scavenger, and thus we examined the clinical and neuroprotective effects of nPt in ischemic mouse brains. Mice were subjected to transient middle cerebral artery occlusion (tMCAO) for 60 min and divided into the following four groups by intravenous administration upon reperfusion, vehicle, tPA, tPA+nPt, and nPt. At 48 h after tMCAO, motor function, infarct volume, immunohistochemical analyses of neurovascular unit (NVU), in vivo imaging of matrix metalloproteinase (MMP), and zymography for MMP-9 activity were examined. Superoxide anion generation at 2h after tMCAO was also examined with hydroethidine (HEt). As a result, administration of tPA deteriorated the motor function and infarct volume as compared to vehicle. In vivo optical imaging of MMP showed strong fluorescent signals in affected regions of tMCAO groups. Immunohistochemical analyses revealed that tMCAO resulted in a minimal decrease of NAGO and occludin, but a great decrease of collagen IV and a remarkable increase of MMP-9. HEt stain showed increased ROS generation by tMCAO. All these results became pronounced with tPA administration, and were greatly reduced by nPt. The present study demonstrates that nPt treatment ameliorates neurological function and brain damage in acute cerebral infarction with neuroprotective effect on NVU and inactivation of MMP-9. The strong reduction of ROS production by nPt could account for these remarkable neurological and neuroprotective effects against ischemic stroke.

Ischemic stroke is a major, urgent neurologic disorder in which reactive oxygen species (ROS) are deeply involved in the detrimental effects. Platinum nanoparticle (nPt) species are a novel and strong scavenger of such ROS, so we examined the clinical and neuroprotective effects of nPts in mouse ischemic brain. Mice were subjected to transient middle cerebral artery occlusion (tMCAO) for 60 min. Upon reperfusion, nPt or vehicle was administered intravenously. At 48 hr after the tMCAO, motor function, infarct volume, immunohistochemistry of neurovascular components (endothelial NAGO, tight junctional occludin, and basal laminal collagen IV), and zymography for MMP-9 activity were examined. Superoxide anion generation at 2 hr after tMCAO was determined with oxidized hydroethidine. Compared with vehicle, treatment with nPts significantly improved the motor function and greatly reduced the infarct volume, especially in the cerebral cortex. Immunohistochemical analyses revealed that tMCAO resulted in a minimal decrease of NAGO and occludin but a great decrease of collagen IV and a remarkable increase of MMP-9. Treatment with nPts greatly reduced this decrease of collagen IV and activation of MMP-9 and, with large reductions of MMP-9 activation on zymography and superoxide production. The present study demonstrates that treatment with nPts ameliorates the neurological scores with a large reduction in infarct size as well as the preservation of outer components of the neurovascular unit (collagen IV) and inactivation of MMP-9. A strong reduction of superoxide anion production by nPts could account for such remarkable neurobehavioral and neuroprotective effects on ischemic stroke.

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BackgroundWe report a female patient with familial Creutzfeldt-Jakob disease with V180I mutation (fCJD with V180I), who was serially followed up with magnetic resonance imaging (MRI) and electroencephalogram (EEG) for up to four years.Case presentationAt 6 months after the onset, diffusion-weighted images (DWI) and fluid-attenuated inversion recovery (FLAIR) of brain MRI revealed an increased signal intensity in the bilateral frontal, temporal, and parietal cerebral cortex with left dominancy except for the occipital lobe. However, her follow-up MRI at four years showed the high-signal regions spreading to the occipital cerebral cortex in DWI and FLAIR images, and bilateral frontal cerebral white matter in FLAIR images. EEG showed a progressive and general slow high-voltage rhythm from 7–8 to 3–5 c/s over four years, without evidence of periodic synchronous discharge. These findings correspond to the symptom progression even after akinetic mutism at 18 months.ConclusionWe suggest that serial MRI and EEG examinations are useful for early diagnosis of fCJD with V180I and for monitoring disease progression.