Description: Background and Purpose— Toward the goal of designing a clinical trial using imaging parameters to treat stroke patients with unknown onset time, we investigated the timing of changes on MRI in patients with well-defined stroke onset. Methods— Hypothesis-generating (n=85) and confirmatory (n=111) samples were scored by blinded readers for fluid-attenuated inversion recovery (FLAIR) hyperintensity in diffusion-positive regions. Reader-measured signal intensity ratio (SIR) of the lesion to contralateral tissue was compared with SIR measured by coregistration. Results— Lesion conspicuity increased with time on FLAIR ( P =0.006). Qualitative assessment of FLAIR-negative vs FLAIR hyperintensity (k=0.7091; 95% CI, 0.61–0.81) showed good interrater agreement. Subtle hyperintensity was less reliably categorized (k=0.59; 95% CI, 0.47–0.71). Reader-measured SIR 〈1.15 can identify patients within the treatable time window of 4.5 hours (positive predictive value=0.90). The SIR was greater for right hemisphere lesions ( P =0.04) for a given reported time from stroke symptom onset. Conclusion— The SIR on FLAIR provides a quantitative tool to identify early ischemic strokes. In developing SIR thresholds, right hemisphere lesions may confound the accurate estimate of stroke onset time. Image coregistration for thrombolytic trial enrollment is not necessary. A SIR 〈1.15 on FLAIR yields a practical estimate of stroke onset within 4.5 hours.

Description: Background and Purpose— States and counties in the US began implementing regional systems of acute stroke care in the first decade of the 21st century, whereby emergency medical services systems preferentially route acute stroke patients directly to primary stroke centers. The pace, geographic range, and population reach of regional stroke system implementation has not been previously delineated. Methods— We performed a review of legislative archives, internet and media reports, consultation with American Heart Association/American Stroke Association and Centers for Disease Control staff, and phone interviews with state public health and emergency medical service officials from each of the 50 states. Results— The first counties to adopt regional regulations supporting routing of acute stroke patients to primary stroke centers were in Alabama and Texas in 2000; the first states were Florida and Massachusetts in 2004. By 2010, 16 states had state-level legislation or regulations to enable emergency medical service routing to primary stroke centers, as did counties in 3 additional states. The US population covered by routing protocols increased substantially in the latter half of the decade, from 1.5% in 2000 to 53% of the US population by the end of 2010. Conclusions— The first decade of the 21st century witnessed a remarkable structural transformation in acute stroke care: by the end of 2010, over half of all Americans were living in states/counties with emergency medical service routing protocols supporting the direct transport of acute stroke patients to primary stroke centers. Additional efforts are needed to extend regional stroke systems of care to the rest of the US.

Description: Background and Purpose— Some patients treated with intravenous (IV) tissue-type plasminogen activator (tPA) have negative diffusion-weighted imaging (DWI) on follow-up imaging. Without a visible infarct, there may be uncertainty as to whether the patient was having a stroke that was averted by tPA or whether the symptoms had not been cerebrovascular in origin. We evaluated patients presenting with suspected acute stroke with a positive DWI lesion before IV tPA to determine the probability of finding a negative DWI up to 48 hours after treatment. Methods— We included patients from the Lesion Evolution in Stroke and Ischemia On Neuroimaging (LESION) project who had acute MRI screening with a positive DWI lesion before IV tPA treatment and had follow-up MRI up to 48 hours later. Experienced readers interpreted all acute and follow-up MRIs looking for ischemic lesions on DWI. Results— There were 231 patients who met study inclusion criteria, of which 225 patients (97.4%) had a persistent positive DWI corresponding to the acute stroke lesion on all follow-up imaging. Four patients (1.7%) had transient DWI lesion reversal with positive DWI on subsequent follow-up imaging. There were only 2 cases (0.9%) of complete DWI lesion reversal on all follow-up imaging. Conclusions— Averted infarction after IV tPA is rare, occurring in 0.9% of patients with pretreatment positive DWI evidence of acute ischemia. For IV tPA-treated patients who have a negative DWI on follow-up imaging, a cause other than acute stroke should be explored.

Description: The role of type III transforming growth factor-β receptor (TβRIII) in the pathogenesis of heart diseases remains largely unclear. Here, we investigated the functional role and molecular mechanisms of TβRIII in the development of myocardial hypertrophy. Western blot and quantitative real time-polymerase chain reaction analyses revealed that the expression of TβRIII was significantly elevated in human cardiac hypertrophic samples. Consistently, TβRIII expression was substantially increased in transverse aortic constriction (TAC)– and isoproterenol-induced mouse cardiac hypertrophy in vivo and in isoproterenol-induced cardiomyocyte hypertrophy in vitro. Overexpression of TβRIII resulted in cardiomyocyte hypertrophy, whereas isoproterenol-induced cardiomyocyte hypertrophy was greatly attenuated by knockdown of TβRIII in vitro. Cardiac-specific transgenic expression of TβRIII independently led to cardiac hypertrophy in mice, which was further aggravated by isoproterenol and TAC treatment. Cardiac contractile function of the mice was not altered in TβRIII transgenic mice; however, TAC led to significantly decreased cardiac contractile function in TβRIII transgenic mice compared with control mice. Conversely, isoproterenol- and TAC-induced cardiac hypertrophy and TAC-induced cardiac contractile function impairment were partially reversed by suppression of TβRIII in vivo. Our data suggest that TβRIII mediates stress-induced cardiac hypertrophy through activation of Ca 2+ /calmodulin-dependent protein kinase II, which requires a physical interaction of β-arrestin2 with both TβRIII and calmodulin-dependent protein kinase II. Our findings indicate that stress-induced increase in TβRIII expression results in cardiac hypertrophy through β-arrestin2–dependent activation of calmodulin-dependent protein kinase II and that transforming growth factor-β and β-adrenergic receptor signaling are not involved in spontaneous cardiac hypertrophy in cardiac-specific transgenic expression of TβRIII mice. Our findings may provide a novel target for control of myocardial hypertrophy.

Description: Background and Purpose— Get With The Guidelines (GWTG)-Stroke is a national, hospital-based quality improvement program developed by the American Heart Association. Although studies have suggested improved processes of care in GWTG-Stroke–participating hospitals, it is not known whether this improved care translates into improved clinical outcomes compared with nonparticipating hospitals. Methods— From all acute care US hospitals caring for Medicare beneficiaries with acute stroke between April 2003 and December 2008, we matched hospitals that joined the GWTG-Stroke program with similar hospitals that did not. Using a difference-in-differences design, we analyzed whether hospital participation in GWTG-Stroke was associated with a greater improvement in clinical outcomes compared with the underlying secular change. Results— The matching algorithm identified 366 GWTG-Stroke–adopting hospitals that cared for 88 584 acute ischemic stroke admissions and 366 non–GWTG-Stroke hospitals that cared for 85 401 acute ischemic stroke admissions. Compared with the Pre period (18–6 months before program implementation), in the Early period (0–6 months after program implementation), GWTG-Stroke hospitals had accelerated increases in discharge to home and reduced mortality at 30 days and 1 year. In the Sustained period (6–18 months after program implementation), the accelerated reduction in mortality at 1 year was sustained, with a trend toward sustained accelerated increase in discharge home. Conclusions— Hospital adoption of the GWTG-Stroke program was associated with improved functional outcomes at discharge and reduced postdischarge mortality.

Description: Rationale: Vascular endothelial growth factor (VEGF) signaling is a key pathway for angiogenesis and requires highly coordinated regulation. Although the Notch pathway-mediated suppression of excessive VEGF activity via negative feedback is well known, the positive feedback control for augmenting VEGF signaling remains poorly understood. Transcription factor Sox17 is indispensable for angiogenesis, but its association with VEGF signaling is largely unknown. The contribution of other Sox members to angiogenesis also remains to be determined. Objective: To reveal the genetic interaction of Sox7, another Sox member, with Sox17 in developmental angiogenesis and their functional relationship with VEGF signaling. Methods and Results: Sox7 is expressed specifically in endothelial cells and its global and endothelial-specific deletion resulted in embryonic lethality with severely impaired angiogenesis in mice, substantially overlapping with Sox17 in both expression and function. Interestingly, compound heterozygosity for Sox7 and Sox17 phenocopied vascular defects of Sox7 or Sox17 homozygous knockout, indicating that the genetic cooperation of Sox7 and Sox17 is sensitive to their combined gene dosage. VEGF signaling upregulated both Sox7 and Sox17 expression in angiogenesis via mTOR pathway. Furthermore, Sox7 and Sox17 promoted VEGFR2 (VEGF receptor 2) expression in angiogenic vessels, suggesting a positive feedback loop between VEGF signaling and SoxF. Conclusions: Our findings demonstrate that SoxF transcription factors are indispensable players in developmental angiogenesis by acting as positive feedback regulators of VEGF signaling.

Description: Objective— Vascular smooth muscle cells (VSMCs) modulate their phenotype between synthetic and contractile states in response to environmental changes; this modulation plays a crucial role in the pathogenesis of restenosis and atherosclerosis. Here, we identified fibroblast growth factor 12 (FGF12) as a novel key regulator of the VSMC phenotype switch. Approach and Results— Using murine models and human specimens, we found that FGF12 was highly expressed in contractile VSMCs of normal vessel walls but was downregulated in synthetic VSMCs from injured and atherosclerotic vessels. In human VSMCs, FGF12 expression was inhibited at the transcriptional level by platelet-derived growth factor-BB. Gain- and loss-of-function experiments showed that FGF12 was both necessary and sufficient for inducing and maintaining the quiescent and contractile phenotypes of VSMCs. FGF12 inhibited cell proliferation through the p53 pathway and upregulated the key factors involved in VSMC lineage differentiation, such as myocardin and serum response factor. Such FGF12-induced phenotypic change was mediated by the p38 MAPK (mitogen-activated protein kinase) pathway. Moreover, FGF12 promoted the differentiation of mouse embryonic stem cells and the transdifferentiation of human dermal fibroblasts into SMC-like cells. Furthermore, adenoviral infection of FGF12 substantially decreased neointima hyperplasia in a rat carotid artery injury model. Conclusions— In general, FGF family members induce a synthetic VSMC phenotype. Interestingly, the present study showed the unanticipated finding that FGF12 belonging to FGF family, strongly induced the quiescent and contractile VSMC phenotypes and directly promoted VSMC lineage differentiation. These novel findings suggested that FGF12 could be a new therapeutic target for treating restenosis and atherosclerosis.

Description: Background and Purpose— Elevated concentrations of homocysteine are associated with cerebral small vessel disease (CSVD). b-vitamin supplementation with folate and vitamins b 12 and b 6 reduces homocysteine concentrations. In a substudy of the VITAmins TO Prevent Stroke (VITATOPS) trial, we assessed the hypothesis that the addition of once-daily supplements of b vitamins would reduce the progression of CSVD-related brain lesions. Methods— A total of 359 patients with recent stroke or transient ischemic attack, who were randomly allocated to double-blind treatment with placebo or b vitamins, underwent brain MRI at randomization and after 2 years of b-vitamin supplementation. MR images were analyzed blinded to treatment allocation. Outcomes related to the prespecified hypothesis were progression of white matter hyperintensities and incident lacunes. We also explored the effect of b-vitamin supplementation on the incidence of other ischemic abnormalities. Results— After 2 years of treatment with b vitamins or placebo, there was no significant difference in white matter hyperintensities volume change (0.08 vs 0.13cm 3 ; P =0.419) and incidence of lacunes (8.0% vs 5.9%, P =0.434; odds ratio=1.38). In a subanalysis of patients with MRI evidence of severe CSVD at baseline, b-vitamin supplementation was associated with a significant reduction in white matter hyperintensities volume change (0.3 vs 1.7cm 3 ; P =0.039). Conclusions— Daily b-vitamin supplementation for 2 years did not significantly reduce the progression of brain lesions resulting from presumed CSVD in all patients with recent stroke or transient ischemic attack but may do so in the subgroup of patients with recent stroke or transient ischemic attack and severe CSVD. Clinical Trial Registration— http://vitatops.highway1.com.au/ . Unique identifier: NCT00097669 and ISRCTN74743444.

Description: Background Endothelium-derived acetylcholine (eACh) plays an important role in the regulation of vascular actions in response to hypoxia, whereas arterial baroreflex (ABR) dysfunction impairs the eACh system. We investigated the effects of ABR dysfunction on ischemia-induced angiogenesis in animal models of hindlimb ischemia with a special focus on eACh/nicotinic ACh receptor (nAChR) signaling activation. Methods and Results Male Sprague-Dawley rats were randomly assigned to 1 of 3 groups that received (1) sham operation (control group), (2) sinoaortic denervation (SAD)-induced ABR dysfunction (SAD group), or (3) SAD rats on diet with an acetylcholinesterase inhibitor pyridostigmine (30 mg/kg per day, SAD+Pyr group). After 4 weeks of the SAD intervention, unilateral limb ischemia was surgically induced in all animals. At postoperative day 14, SAD rats exhibited impaired angiogenic action (skin temperature and capillary density) and decreased angiogenic factor expressions (vascular endothelial growth factor [VEGF] and hypoxic inducible factor [HIF]-1α) in ischemic muscles. These changes were restored by acetylcholinesterase inhibition. Rats with ABR dysfunction had lower eACh levels than did control rats, and this effect was recovered in SAD+Pyr rats. In α7-nAChR knockout mice, pyridostigmine improved ischemia-induced angiogenic responses and increased the levels of VEGF and HIF-1α. Moreover, nicotinic receptor blocker inhibited VEGF expression and VEGF receptor 2 phosphorylation (p-VEGFR2) induced by ACh analog. Conclusions Thus, ABR dysfunction appears to impair ischemia-induced angiogenesis through the reduction of eACh/α7-nAChR-dependent and -independent HIF-1α/VEGF-VEGFR2 signaling activation.

Description: Background Cardiomyocytes that differentiate from pluripotent stem cells (PSCs) provide a crucial cellular resource for cardiac regeneration. The mechanisms of mitochondrial metabolic and redox regulation for efficient cardiomyocyte differentiation are, however, still poorly understood. Here, we show that inhibition of the mitochondrial permeability transition pore (mPTP) by Cyclosporin A (CsA) promotes cardiomyocyte differentiation from PSCs. Methods and Results We induced cardiomyocyte differentiation from mouse and human PSCs and examined the effect of CsA on the differentiation process. The cardiomyogenic effect of CsA mainly resulted from mPTP inhibition rather than from calcineurin inhibition. The mPTP inhibitor NIM811, which does not have an inhibitory effect on calcineurin, promoted cardiomyocyte differentiation as much as CsA did, but calcineurin inhibitor FK506 only slightly increased cardiomyocyte differentiation. CsA-treated cells showed an increase in mitochondrial calcium, mitochondrial membrane potential, oxygen consumption rate, ATP level, and expression of genes related to mitochondrial function. Furthermore, inhibition of mitochondrial oxidative metabolism reduced the cardiomyogenic effect of CsA while antioxidant treatment augmented the cardiomyogenic effect of CsA. Conclusions Our data show that mPTP inhibition by CsA alters mitochondrial oxidative metabolism and redox signaling, which leads to differentiation of functional cardiomyocytes from PSCs.