記述言語：英語   掲載種別：研究論文（学術雑誌）  

Remote ischemic conditioning (RIC) has attracted much attention as a protective strategy for the heart and brain, although the underlying mechanisms remain unclear. We hypothesized that RIC enhances collateral circulation during cerebral ischemia through endothelial function and mitigates both early ischemic change and final infarct volume. We tested the RIC and sham procedure 30 min after permanent middle cerebral artery occlusion (MCAO) in male mice. Collateral circulation was examined during the procedure with 2D color-coded ultrasound imaging. Immediately after four cycles of RIC, early ischemic lesions on magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and development of pial collateral vessels were examined. The neurological signs and infarct volume with TTC were examined until 48 h after daily RIC. As compared with sham procedure, RIC enhanced collateral circulation, diminished early ischemic lesions, enlarged pial collaterals, and mitigated infarct volume. Next, we examined the effect of inhibitor of nitric oxide synthase (NOS) and Akt on the beneficial effect of RIC in MCAO. Both allosteric Akt inhibitor, 8-[4-(1-Aminocyclobutyl)phenyl]-9-phenyl[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3(2H)-one (MK2206), and two NOS inhibitors, N5-(1-Iminoethyl)-L-ornithine dihydrochloride (L-NIO) and NG-Nitro-L-arginine methyl ester hydrochloride (L-NAME), counteracted the beneficial effect of RIC on collateral circulation, early lesions, pial anastomosis, and infarct volume. In permanent MCAO, RIC could enhance collateral circulation through leptomeningeal anastomosis with Akt-eNOS pathway and diminish early lesion and final infarct volume.

DOI： 10.1007/s12975-022-01108-2

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

MRI diffusion-weighted imaging (DWI)-FLAIR mismatch is known as predictive of symptom onset within 4.5 h. This study assessed the breakdown of cytoskeletal protein and blood-brain barrier (BBB) in DWI-T2 mismatch. We employed occlusion of middle cerebral artery (MCAO) in C57BL/6 mice. We serially measured MRI including DWI and T2WI. After MRI, we prepared brain sections or samples and examined microtubule-associated protein 2 (MAP2) expression, alpha-fodrin degradation, extravasation of albumin and claudin-5 expression. In permanent or transient MCAO for 45 min, DWI hyperintensities was already found at 60 min without change of T2, showing DWI-T2 mismatch. In permanent MCAO, MAP2 expressions were preserved, and no extravasation of albumin was observed. In transient MCAO, MAP2 immunoreaction was already lost in the lateral part of the striatum. In both models, alpha-fodrin degradation was already detected. At 180 min, T2 hyperintensities appeared, where MAP2 signal was lost and albumin extravasation was found. At 24 h, hyperintensities of DWI and T2WI was found in the whole MCA territory, where MAP2 signal was completely lost with marked albumin extravasation and alpha-fodrin degradation. Immunoreaction for claudin-5 was preserved up to 180 min. DWI-T2 mismatch area may not always indicate intactness of cytoskeletal protein but shows preservation of BBB.

DOI： 10.1016/j.neures.2022.11.005

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Hypertension is the most important risk factor for cerebral small vessel disease (SVD). In this cross-sectional study, we tested the independent association of cerebral SVD burden with global cognitive function and each cognitive domain in patients with vascular risk factors. The Tokyo Women's Medical University Cerebral Vessel Disease (TWMU CVD) registry is an ongoing prospective, observational registry in which patients with any evidence of CVD in magnetic resonance imaging (MRI) and at least one vascular risk factor were consecutively enrolled. For SVD-related findings, we evaluated white matter hyperintensity, lacunar infarction, cerebral microbleeds, enlarged perivascular space, and medial temporal atrophy. We used the total SVD score as the SVD burden. They underwent the Mini-mental State Examination (MMSE) and Japanese version of the Montreal Cognitive Assessment (MoCA-J) global cognitive tests, and each cognitive domain was evaluated. After excluding patients without MRI T2* images and those with MMSE score <24, we analyzed 648 patients. The total SVD score was significantly associated with MMSE and MoCA-J scores. After adjustment for age, sex, education, risk factors, and medial temporal atrophy, the association between the total SVD score and MoCA-J score remained significant. The total SVD score was independently associated with attention. In conclusion, the total SVD score, cerebral SVD burden, was independently association with global cognitive function and attention. A strategy to reduce SVD burden will have the potential to prevent cognitive decline. A total of 648 patients with any evidence of cerebral small vessel disease (SVD) in MRI and at least one vascular risk factor underwent Mini-mental State Examination (MMSE) and Japanese version of the Montreal Cognitive Assessment (MoCA-J) global cognitive tests. The total SVD scores count the presence of each SVD-related findings (white matter hyperintensity, Lacunar infarction, cerebral microbleeds and enlarged perivascular space), ranging from 0 to 4, as the SVD burden. Total SVD scores were significantly associated with MoCA-J scores (r = -0.203, P < 0.001). After adjustment for age, sex, education, risk factors, and medial temporal atrophy, the association between the total SVD score and global cognitive scores remained significant.

DOI： 10.1038/s41440-023-01244-8

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: Remote ischemic conditioning (RIC) refers to the application of repeated short periods of ischemia intended to protect remote areas against tissue damage during and after prolonged ischemia. AIM: We aim to evaluate the efficacy of RIC, determined by the modified Rankin Scale (mRS) score at 90 days after stroke onset. DESIGN AND METHODS: This study is an investigator-initiated, multicenter, prospective, randomized, open-label, parallel-group clinical trial. The sample size is 400, comprising 200 patients who will receive RIC and 200 controls. The patients will be divided into three groups according to their National Institutes of Health Stroke Scale score at enrollment: 5-9, mild; 10-14, moderate; 15-20, severe. The RIC protocol will be comprised of four cycles, each consisting of 5 min of blood pressure cuff inflation (at 200 mmHg or 50 mmHg above the systolic blood pressure) followed by 5 min of reperfusion, with the cuff placed on the thigh on the unaffected side. The control group will only undergo blood pressure measurements before and after the intervention period. This trial is registered with the UMIN Clinical Trial Registry (https://www.umin.ac.jp/: UMIN000046225). STUDY OUTCOME: The primary outcome will be a good functional outcome as determined by the mRS score at 90 days after stroke onset, with a target mRS score of 0-1 in the mild group, 0-2 in the moderate group, and 0-3 in the severe group. DISCUSSION: This trial may help determine whether RIC should be recommended as a routine clinical strategy for patients with ischemic stroke.

DOI： 10.3389/fneur.2022.946431

PubMed

researchmap

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Leptomeningeal anastomosis is a key factor for determining early ischemic lesions on diffusion-weighted imaging (DWI) in human stroke. However, few studies have validated this relationship in an experimental model. This study sought to clarify the involvement of leptomeningeal anastomosis in early ischemic lesions using a murine model. Adult male C57BL/6 mice were subjected to unilateral common carotid artery (CCA) occlusion or sham surgery. Seven or 14 days later, the middle cerebral artery (MCA) was occluded for 45 min. In the first experiment, the leptomeningeal collaterals were visualized using magnetic resonance imaging (MRI) DWI. In the second experiment, DWI was performed immediately after MCA occlusion, and the infarct sizes were determined 24 hr after recirculation. Unilateral CCA occlusion reduced the size of early ischemic lesions, enlarged the pial vessel diameter, and mitigated infarct size. The relationship between the DWI lesion size and pial vessel diameter was significant (r = 0.84, p < 0.01). The association between infarct size and DWI lesion size was also significant (r = 0.96, p < 0.01). In conclusion, involvement of the collateral circulation in early ischemic lesions was evident in the murine model. Both MRI and evaluation of leptomeningeal anastomosis could be used to develop a novel strategy targeting enhancement of the collateral circulation.

DOI： 10.1002/jnr.24403

PubMed

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

researchmap

researchmap

researchmap

researchmap

researchmap