Background-Considerable controversy exists regarding impairment of cardiac function in diabetes mellitus (DM). We investigated the serial changes in left ventricular (LV) histopathology and LV filling dynamics in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which have been established as an animal model of type II DM. Methods and Results-In 54 OLETF and 54 non-DM rats, body weight, blood pressure, heart rate, and transmitral pulsed Doppler examinations were performed from 5 to 47 weeks of age. An oral glucose tolerance test was performed at 10, 20, and 30 weeks of age. The hearts were excised for histopathology, including immunohistochemistry and histomorphometry of collagen, and measurement of hydroxyproline at baseline and each stage of developing DM. In the prediabetic stage (15 weeks of age), in which fast blood glucose remained normal, OLETF rats manifested mild obesity, postprandial hyperglycemia, and hyperinsulinemia, and early diastolic transmitral inflow exhibited prolonged deceleration time (OLETF, 59Ϯ10 ms versus non-DM, 49Ϯ8 ms, PϽ0.01) and low peak velocity (OLETF, 73Ϯ11 cm/s versus non-DM, 88Ϯ11 cm/s, PϽ0.01). Histopathology revealed extracellular fibrosis and abundant transforming growth factor-␤ 1 receptor II in LV myocytes of OLETF rats. At 15 weeks of age, the ratio of collagen area/visual field of LV wall in OLETF rats (8.3Ϯ1.3%) was larger than that in non-DM rats (4.9Ϯ1.8%, PϽ0.0001), and the collagen content/dry tissue weight ratio of heart was significantly higher in OLETF (2.0Ϯ0.5 mg/g) than non-DM (1.3Ϯ0.2 mg/g, PϽ0.01) rats.

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BackgroundAlthough statin therapy is beneficial for the prevention of initial stroke, the benefit for recurrent stroke and its subtypes remains to be determined in Asian, in whom stroke profiles are different from Caucasian. This study examined whether treatment with low-dose pravastatin prevents stroke recurrence in ischemic stroke patients.MethodsThis is a multicenter, randomized, open-label, blinded-endpoint, parallel-group study of patients who experienced non-cardioembolic ischemic stroke. All patients had a total cholesterol level between 4.65 and 6.21 mmol/L at enrollment, without the use of statins. The pravastatin group patients received 10 mg of pravastatin/day; the control group patients received no statins. The primary endpoint was the occurrence of stroke and transient ischemic attack (TIA), with the onset of each stroke subtype set to be one of the secondary endpoints.FindingAlthough 3000 patients were targeted, 1578 patients (491 female, age 66.2 years) were recruited and randomly assigned to pravastatin group or control group. During the follow-up of 4.9 ± 1.4 years, although total stroke and TIA similarly occurred in both groups (2.56 vs. 2.65%/year), onset of atherothrombotic infarction was less frequent in pravastatin group (0.21 vs. 0.64%/year, p = 0.0047, adjusted hazard ratio 0.33 [95%CI 0.15 to 0.74]). No significant intergroup difference was found for the onset of other stroke subtypes, and for the occurrence of adverse events.InterpretationAlthough whether low-dose pravastatin prevents recurrence of total stroke or TIA still needs to be examined in Asian, this study has generated a hypothesis that it may reduce occurrence of stroke due to larger artery atherosclerosis.FundingThis study was initially supported by a grant from the Ministry of Health, Labour and Welfare, Japan. After the governmental support expired, it was conducted in collaboration between Hiroshima University and the Foundation for Biomedical Research and Innovation.

During focal cerebral ischemia, matrix metalloproteinase-2 (MMP-2) can contribute to the loss of microvessel integrity within ischemic regions by degrading the basal lamina. MMP-2 is secreted in latent form (pro-MMP-2), but the activation of pro-MMP-2 in the ischemic territory has not been shown. Immunohistochemical and in situ hybridization studies of the expression of the direct activators of MMP-2, MT1-MMP and MT3-MMP, and the indirect activation system tissue plasminogen activator, urokinase (u-PA), its receptor (u-PAR), and its inhibitor PAI-1 after middle cerebral artery occlusion/reperfusion were undertaken in basal ganglia samples from 26 adolescent male baboons. The expressions of all three MMPs, u-PA, u-PAR, and PA1-1, but not tissue plasminogen activator, were increased from 1 hour after middle cerebral artery occlusion in the ischemic core. mRNA transcripts confirmed the increases in latent MMP-2, u-PA, u-PAR, and PAI-1 antigen very early after middle cerebral artery occlusion. The expression patterns are consistent with secretion of pro-MMP-2 and its activators in the ischemic core, perhaps from separate cell compartments. The rapid and coordinate appearance of pro-MMP-2 and its activation apparatus suggest that in the primate striatum this protease may participate in matrix injury during focal cerebral ischemia.

Hemorrhage and edema accompany evolving brain tissue injury after ischemic stroke. In patients, these events have been associated with metalloproteinase (MMP)-9 in plasma. Both the causes and cellular sources of MMP-9 generation in this setting have not been defined. MMP-2 and MMP-9 in nonhuman primate tissue in regions of plasma leakage, and primary murine microglia and astrocytes, were assayed by immunocytochemistry, zymography, and real-time RT-PCR. Ischemia-related hemorrhage was associated with microglial activation in vivo, and with the leakage of plasma fibronectin and vitronectin into the surrounding tissue. In strict serum-depleted primary cultures, by zymography, pro-MMP-9 was generated by primary murine microglia when exposed to vitronectin and fibronectin. Protease secretion was enhanced by experimental ischemia (oxygen-glucose deprivation, OGD). Primary astrocytes, on each matrix, generated only pro-MMP-2, which decreased during OGD. Microglia—astrocyte contact enhanced pro-MMP-9 generation in a cell density-dependent manner under normoxia and OGD. Compatible with observations in a high quality model of focal cerebral ischemia, microglia, but not astrocytes, respond to vitronectin and fibronectin, found when plasma extravasates into the injured region. Astrocytes alone do not generate pro-MMP-9. These events explain the appearance of MMP-9 antigen in association with ischemia-induced cerebral hemorrhage and edema.

Background and Purpose-During focal cerebral ischemia, the microvascular matrix (ECM), which participates in microvascular integrity, is degraded and lost when neurons are injured. Loss of microvascular basal lamina antigens coincides with rapid expression of select matrix metalloproteinases (MMPs). Plasminogen activators (PAs) may also play a role in ECM degradation by the generation of plasmin or by MMP activation. Methods-The endogenous expressions of tissue-type plasminogen activator (tPA), urokinase (uPA), and PA inhibitor-1 (PAI-1) were quantified in 10-m frozen sections from ischemic and matched nonischemic basal ganglia and in the plasma of 34 male healthy nonhuman primates before and after middle cerebral artery occlusion (MCA:O). Results-Within the ischemic basal ganglia, tissue uPA activity and antigen increased significantly within 1 hour after MCA:O (2PϽ0.005). tPA activity transiently decreased 2 hours after MCA:O (2Pϭ0.01) in concert with an increase in PAI-1 antigen (2Pϭ0.001) but otherwise did not change. The transient decrease in free tPA antigen was marked by an increase in the tPA-PAI-1 complex (2PϽ0.001). No significant relations to neuronal injury or intracerebral hemorrhage were discerned. Conclusions-The rapid increase in endogenous PA activity is mainly due to significant increases in uPA, but not tPA, within the ischemic basal ganglia after MCA:O. This increase and an increase in PAI-1 coincided with latent MMP-2 generation and microvascular ECM degeneration but not neuronal injury.

Background and Purpose-Determining the underlying cause of stroke is important to optimize secondary prevention treatment. Increased blood levels of natriuretic peptides (B-type natriuretic peptide/N-terminal pro-BNP [BNP/ NT-proBNP]) have been repeatedly associated with cardioembolic stroke. Here, we evaluate their clinical value as pathogenic biomarkers for stroke through a literature systematic review and individual participants' data meta-analysis. Methods-We searched publications in PubMed database until November 2013 that compared BNP and NT-proBNP circulating levels among stroke causes. Standardized individual participants' data were collected to estimate predictive values of BNP/NT-proBNP for cardioembolic stroke. Dichotomized BNP/NT-proBNP levels were included in logistic regression models together with clinical variables to assess the sensitivity and specificity to identify cardioembolic strokes and the additional value of biomarkers using area under the curve and integrated discrimination improvement index. Results-From 23 selected articles, we collected information of 2834 patients with a defined cause. BNP/NT-proBNP levels were significantly elevated in cardioembolic stroke until 72 hours from symptoms onset. Predictive models showed a sensitivity >90% and specificity >80% when BNP/NT-proBNP were added considering the lowest and the highest quartile, respectively. Both peptides also increased significantly the area under the curve and integrated discrimination improvement index compared with clinical models. Sensitivity, specificity, and precision of the models were validated in 197 patients with initially undetermined stroke with final pathogenic diagnosis after ancillary follow-up. Conclusions-Natriuretic peptides are strongly increased in cardioembolic strokes. Future multicentre prospective studies comparing BNP and NT-proBNP might aid in finding the optimal biomarker, the best time point, and the optimal cutoff points for cardioembolic stroke identification. 2 Patients with cardioembolic stroke are treated with anticoagulant drugs, whereas antiplatelet agents are the treatment of choice for patients with large artery atherosclerosis (LAA) stroke and small vessel disease (SVD).3 Cardioembolic strokes are generally more severe and more prone to recurrence than LAA or SVD and account for approximately one fifth of ischemic strokes. 4 However, in spite of the importance of an accurate etiopathogenic classification, the cause of ≈35% of patients remains undetermined, even after complete evaluation.5 This group of patients presents a rate of recurrence of ≈30% during the first year after the event, partly explained by an inappropriate secondary prevention treatment.6 Stroke of undetermined cause is an heterogeneous group that includes patients with 2 or more potential causes of stroke, patients with <50% of stenosis and patients with a negative diagnostic workup.7 From the latter, a negative diagnostic might be caused by a transitory or reversible condition which is difficult to detect, such as a...

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