Description: Background and Purpose— In patients with ischemic stroke, randomized trials showed a better functional outcome after endovascular therapy with new-generation thrombectomy devices compared with medical treatment, including intravenous thrombolysis. However, effects on mortality and the generalizability of results to routine clinical practice are uncertain. Methods— In a prospective observational register-based study patients with ischemic stroke treated either with thrombectomy, intravenous thrombolysis, or their combination were included. Primary outcome was the modified Rankin scale score (0 [no symptoms] to 6 [death]) at 3 months. Ordinal logistic regression was used to estimate the common odds ratio as treatment effects (shift analysis). Propensity score matching was applied to compare patients treated either with intravenous thrombolysis alone or with intravenous thrombolysis plus thrombectomy. Results— Among 2650 recruited patients, 1543 received intravenous thrombolysis, 504 underwent thrombectomy, and 603 received intravenous thrombolysis in combination with thrombectomy. Later time-to-treatment was associated with worse outcomes among patients treated with thrombectomy plus thrombolysis. In 241 pairs of propensity score–matched patients with a proximal intracranial occlusion, thrombectomy plus thrombolysis was associated with improved functional outcome (common odds ratio, 1.84; 95% confidence interval, 1.32–2.57), and reduced mortality (15% versus 33%; P 〈0.0001) compared with intravenous thrombolysis alone. Results were similar in various sensitivity analyses accounting for missing outcome data and different analytic methods. Conclusions— Results from this large prospective registry show that also in routine clinical care thrombectomy plus thrombolysis compared with thrombolysis alone improved functional outcome and reduced mortality in patients with ischemic stroke. Earlier treatment was associated with better outcomes.

Description: Rationale: The inflammatory processes that initiate and propagate atherosclerosis remain poorly understood, largely because defining the intravascular behavior of immune cells has been technically challenging. Respiratory and pulsatile movements have hampered in vivo visualization of leukocyte accumulation in athero-prone arteries at resolutions achieved in other tissues. Objective: To establish and to validate a method that allows high-resolution imaging of inflammatory leukocytes and platelets within the carotid artery of atherosusceptible mice in vivo. Methods and Results: We have devised a procedure to stabilize the mouse carotid artery mechanically without altering blood dynamics, which dramatically enhances temporal and spatial resolutions using high-speed intravital microscopy in multiple channels of fluorescence. By applying this methodology at different stages of disease progression in atherosusceptible mice, we first validated our approach by assessing the recruitment kinetics of various leukocyte subsets and platelets in athero-prone segments of the carotid artery. The high temporal and spatial resolution allowed the dissection of both the dynamic polarization of and the formation of subcellular domains within adhered leukocytes. We further demonstrate that the secondary capture of activated platelets on the plaque is predominantly mediated by neutrophils. Finally, we couple this procedure with triggered 2-photon microscopy to visualize the 3-dimensional movement of leukocytes in intimate contact with the arterial lumen. Conclusions: The improved imaging of diseased arteries at subcellular resolution presented here should help resolve many outstanding questions in atherosclerosis and other arterial disorders.

Description: Rationale: Sialylation by α2,3-sialyltransferases has been shown to be a crucial glycosylation step in the generation of functional selectin ligands. Recent evidence suggests that sialylation also affects the binding of chemokines to their corresponding receptor. Objective: Because the chemokine receptors for Ccl5 and Ccl2 are important in atherogenic recruitment of neutrophils and monocytes, we here investigated the role of α2,3-sialyltransferase IV (ST3Gal-IV) in Ccl5- and Ccl2-mediated myeloid cell arrest and further studied its relevance in a mouse model of atherosclerosis. Methods and Results: St3Gal4 -deficient myeloid cells showed a reduced binding of Ccl5 and an impaired Ccl5-triggered integrin activation. Correspondingly, Ccl5-induced arrest on tumor necrosis factor-α–stimulated endothelium was almost completely abrogated, as observed in flow chamber adhesion assays and during ex vivo perfusion or intravital microscopy of carotid arteries. Moreover, Ccl5-triggered neutrophil and monocyte extravasation into the peritoneal cavity was severely reduced in St3Gal4 –/– mice. In contrast, St3Gal4 deficiency did not significantly affect Ccl2 binding and only marginally decreased Ccl2-induced flow arrest of myeloid cells. In agreement with the crucial role of leukocyte accumulation in atherogenesis, and the importance of Ccl5 chemokine receptors mediating myeloid cell recruitment to atherosclerotic vessels, St3Gal4 deficiency drastically reduced the size, stage, and inflammatory cell content of atherosclerotic lesions in Apoe –/– mice on high-fat diet. Conclusions: In summary, these findings identify ST3Gal-IV as a promising target to reduce inflammatory leukocyte recruitment and arrest.

Description: Background— Atherosclerosis and vascular remodeling after injury are driven by inflammation and mononuclear cell infiltration. Extracellular RNA (eRNA) has recently been implicated to become enriched at sites of tissue damage and to act as a proinflammatory mediator. Here, we addressed the role of eRNA in high-fat diet–induced atherosclerosis and neointima formation after injury in atherosclerosis-prone mice. Methods and Results— The presence of eRNA was revealed in atherosclerotic lesions from high-fat diet–fed low-density lipoprotein receptor–deficient ( Ldlr –/– ) mice in a time-progressive fashion. RNase activity in plasma increased within the first 2 weeks (44±9 versus 70±7 mU/mg protein; P =0.0012), followed by a decrease to levels below baseline after 4 weeks of high-fat diet (44±9 versus 12±2 mU/mg protein; P 〈0.0001). Exposure of bone marrow–derived macrophages to eRNA resulted in a concentration-dependent upregulation of the proinflammatory mediators tumor necrosis factor-α, arginase-2, interleukin-1β, interleukin-6, and interferon-. In a model of accelerated atherosclerosis after arterial injury in apolipoprotein E–deficient ( ApoE –/– ) mice, treatment with RNase1 diminished the increased plasma level of eRNA evidenced after injury. Likewise, RNase1 administration reduced neointima formation in comparison with vehicle-treated ApoE –/– controls (25.0±6.2 versus 46.9±6.9 x 10 3 μm 2 , P =0.0339) and was associated with a significant decrease in plaque macrophage content. Functionally, RNase1 treatment impaired monocyte arrest on activated smooth muscle cells under flow conditions in vitro and inhibited leukocyte recruitment to injured carotid arteries in vivo. Conclusions— Because eRNA is associated with atherosclerotic lesions and contributes to inflammation-dependent plaque progression in atherosclerosis-prone mice, its targeting with RNase1 may serve as a new treatment option against atherosclerosis.

Description: Background and Purpose— Arterial hypertension is an important risk factor for cerebrovascular diseases, such as transient ischemic attacks or stroke, and represents a major global health issue. The effects of hypertension on cerebral blood flow, particularly at the microvascular level, remain unknown. Methods— Using the spontaneously hypertensive rat (SHR) model, we examined cortical hemodynamic responses on whisker stimulation applying a multimodal imaging approach (multiwavelength spectroscopy, laser speckle imaging, and 2-photon microscopy). We assessed the effects of hypertension in 10-, 20-, and 40-week-old male SHRs and age-matched male Wistar Kyoto rats (CTRL) on hemodynamic responses, histology, and biochemical parameters. In 40-week-old animals, losartan or verapamil was administered for 10 weeks to test the reversibility of hypertension-induced impairments. Results— Increased arterial blood pressure was associated with a progressive impairment in functional hyperemia in 20- and 40-week-old SHRs; baseline capillary red blood cell velocity was increased in 40-week-old SHRs compared with age-matched CTRLs. Antihypertensive treatment reduced baseline capillary cerebral blood flow almost to CTRL values, whereas functional hyperemic signals did not improve after 10 weeks of drug therapy. Structural analyses of the microvascular network revealed no differences between normo- and hypertensive animals, whereas expression analyses of cerebral lysates showed signs of increased oxidative stress and signs of impaired endothelial homeostasis upon early hypertension. Conclusions— Impaired neurovascular coupling in the SHR evolves upon sustained hypertension. Antihypertensive monotherapy using verapamil or losartan is not sufficient to abolish this functional impairment. These deficits in neurovascular coupling in response to sustained hypertension might contribute to accelerate progression of neurodegenerative diseases in chronic hypertension.

Description: Rationale: High-density lipoprotein cholesterol elevation via cholesteryl ester transfer protein (CETP) inhibition represents a novel therapy for atherosclerosis, which also may have relevance for type 2 diabetes mellitus. Objective: The current study assessed the effects of a CETP inhibitor on postprandial insulin, ex vivo insulin secretion, and cholesterol efflux from pancreatic β-cells. Methods and Results: Healthy participants received a daily dose of CETP inhibitor (n=10) or placebo (n=15) for 14 days in a randomized double-blind study. Insulin secretion and cholesterol efflux from MIN6N8 β-cells were determined after incubation with treated plasma. CETP inhibition increased plasma high-density lipoprotein cholesterol, apolipoprotein AI, and postprandial insulin. MIN6N8 β-cells incubated with plasma from CETP inhibitor–treated individuals (compared with placebo) exhibited an increase in both glucose-stimulated insulin secretion and cholesterol efflux over the 14-day treatment period. Conclusions: CETP inhibition increased postprandial insulin and promoted ex vivo β-cell glucose-stimulated insulin secretion, potentially via enhanced β-cell cholesterol efflux.

Description: Background— Abnormal glucose metabolism is a central feature of disorders with increased rates of cardiovascular disease. Low levels of high-density lipoprotein (HDL) are a key predictor for cardiovascular disease. We used genetic mouse models with increased HDL levels (apolipoprotein A-I transgenic [apoA-I tg]) and reduced HDL levels (apoA-I–deficient [apoA-I ko]) to investigate whether HDL modulates mitochondrial bioenergetics in skeletal muscle. Methods and Results— ApoA-I ko mice exhibited fasting hyperglycemia and impaired glucose tolerance test compared with wild-type mice. Mitochondria isolated from gastrocnemius muscle of apoA-I ko mice displayed markedly blunted ATP synthesis. Endurance capacity during exercise exhaustion test was impaired in apoA-I ko mice. HDL directly enhanced glucose oxidation by increasing glycolysis and mitochondrial respiration rate in C2C12 muscle cells. ApoA-I tg mice exhibited lower fasting glucose levels, improved glucose tolerance test, increased lactate levels, reduced fat mass, associated with protection against age-induced decline of endurance capacity compared with wild-type mice. Circulating levels of fibroblast growth factor 21, a novel biomarker for mitochondrial respiratory chain deficiencies and inhibitor of white adipose lipolysis, were significantly reduced in apoA-I tg mice. Consistent with an increase in glucose utilization of skeletal muscle, genetically increased HDL and apoA-I levels in mice prevented high-fat diet–induced impairment of glucose homeostasis. Conclusions— In view of impaired mitochondrial function and decreased HDL levels in type 2 diabetes mellitus, our findings indicate that HDL-raising therapies may preserve muscle mitochondrial function and address key aspects of type 2 diabetes mellitus beyond cardiovascular disease.

Description: Background Stem cells for cardiac repair have shown promise in preclinical trials, but lower than expected retention, viability, and efficacy. Encapsulation is one potential strategy to increase viable cell retention while facilitating paracrine effects. Methods and Results Human mesenchymal stem cells (hMSC) were encapsulated in alginate and attached to the heart with a hydrogel patch in a rat myocardial infarction (MI) model. Cells were tracked using bioluminescence (BLI) and cardiac function measured by transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMR). Microvasculature was quantified using von Willebrand factor staining and scar measured by Masson's Trichrome. Post-MI ejection fraction by CMR was greatly improved in encapsulated hMSC-treated animals (MI: 34±3%, MI+Gel: 35±3%, MI+Gel+hMSC: 39±2%, MI+Gel+encapsulated hMSC: 56±1%; n=4 per group; P 〈0.01). Data represent mean±SEM. By TTE, encapsulated hMSC-treated animals had improved fractional shortening. Longitudinal BLI showed greatest hMSC retention when the cells were encapsulated ( P 〈0.05). Scar size at 28 days was significantly reduced in encapsulated hMSC-treated animals (MI: 12±1%, n=8; MI+Gel: 14±2%, n=7; MI+Gel+hMSC: 14±1%, n=7; MI+Gel+encapsulated hMSC: 7±1%, n=6; P 〈0.05). There was a large increase in microvascular density in the peri-infarct area (MI: 121±10, n=7; MI+Gel: 153±26, n=5; MI+Gel+hMSC: 198±18, n=7; MI+Gel+encapsulated hMSC: 828±56 vessels/mm 2 , n=6; P 〈0.01). Conclusions Alginate encapsulation improved retention of hMSCs and facilitated paracrine effects such as increased peri-infarct microvasculature and decreased scar. Encapsulation of MSCs improved cardiac function post-MI and represents a new, translatable strategy for optimization of regenerative therapies for cardiovascular diseases.