tbuckley/cabot-search huggingface dataset:
Abstract 5328: Excessive Superoxide Production and Endothelial Dysfunction in Cerebral Arteries of Atherosclerotic Mice Are Due to Enhanced Activity of Nox2-containing NADPH-oxidase
Authors: Alyson A Miller, Michael DeSilva, Courtney P Judkins, Henry Diep, Grant R Drummond, Christopher G Sobey
Journal: Circulation (2009)

We tested if enhanced superoxide (O2−) production by Nox2-containing NADPH oxidase leads to impaired endothelial function in cerebral arteries of high fat-fed apolipoprotein E-deficient (ApoE−/−) mice. All mice were fed a high fat diet from 5 wks of age for 7–14 wks. Intracranial cerebral arteries were isolated from C57Bl6/J wild-type (n=13), ApoE−/− (n=26), Nox2−/− (n=10) and novel Nox2−/−/ApoE−/− (n=23) mice. Basal O2− production by cerebral arteries was measured using L012 (100 umol/L)-enhanced chemiluminescence. Endothelial function was assessed in isolated cannulated middle cerebral arteries using a perfusion myograph via the vasoconstrictor response to the nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME; 100 umol/L). Plasma total cholesterol levels of wild-type (n=6), ApoE−/− (n=7) and Nox2−/−/ApoE−/− (n=8) mice were 6.1±0.2, 39.5±5.3, and 41.93±1.6 mg/L, respectively. En face oil red O staining showed that there were no atherosclerotic lesions in aortae of wild-type mice (n=13), whereas aortic lesions were prominent in ApoE−/− mice (~9% of the total aortic surface, n=13). By contrast, no lesions were observed in cerebral arteries from ApoE−/− mice. O2− production was elevated in cerebral arteries from ApoE−/− (35±5 × 103 counts/mg; n=14, P&lt;0.05) versus wild-type (16±2 × 103 counts/mg; n=11) and Nox2−/− (10±2 ×103 counts/mg; n=6) mice. However, in Nox2−/−/ApoE−/− mice, cerebral artery O2− production was not elevated (11±1 ×103 counts/mg; n=17; P&lt; 0.05). The magnitude of L-NAME-induced contractions of isolated middle cerebral arteries from ApoE−/− mice (Δ diameter =−13±4 %; n=6) was &lt;50% of that in wild-type (−34±2 %; n=6) mice, whereas in Nox2−/−/ApoE−/− (−33±10 %; n=6) mice endothelial function was comparable to that in wild-types. By contrast, similar constrictor responses to high K+ (124 mM) were observed in wild-type (−59±4 %), ApoE−/− (−60±5 %), and Nox2−/−/ApoE−/− (−65±3 %) mice. In summary, excessive O2− production and endothelial dysfunction occur in cerebral arteries of atherosclerotic mice even in the absence of lesions. Furthermore, we report for the first time that these changes appear to be exclusively due to increased activity of Nox2-containing NADPH oxidase.
2006 Dickinson W. Richards Memorial Lecture—Wading in the Genomic Pool for Insights Into Lung Vascular Pathobiology
Authors: Joe G.N. Garcia
Journal: Circulation (2006)

The completion of the Human Genome Project enabled rapid, high-throughput genotyping and gene expression profiling, thereby ushering in the era of genomic medicine. The promise of molecular/ genomic medicine is that we may rapidly ascertain a patient’s genetic and molecular profile and thus target highly individualized therapies appropriate to that patient with little risk and high likelihood of success. In this lecture, we present currently available approaches to investigate potential genetic susceptibility factors that have led to the identification of several genes that impact susceptibility, protection, or severity in enigmatic and complex pulmonary syndromes such as acute lung injury (ALI). We highlight the utility of combining advanced bioinformatic techniques with multispecies gene expression profiling as a way to broaden our net for ALI-related genes. This genome-wise approach is the ideal complement to more traditional, hypothesis-based testing of candidate genes. We anticipate that the genome-wide approach will fuel additional analysis of new candidates while allowing for a wide-angle view of key biological processes such as inflammation, coagulation, and cell proliferation. It remains challenging to determine exactly which environmental and genetic factors are relevant within well-phenotyped populations of patients with complex lung disease (such as ALI/ARDS), and we continue to be constrained by our incomplete current understanding of how various factors interact. Nevertheless, with the dawn of the genomic era, the study of lung pathobiology and the elucidation of the molecular basis of complex lung disorders remains a lofty but achievable goal.
Abstract 5056: Genetic Disruption of the ATP-binding Cassette Transporter BCRP1/ABCG2 Impairs Cardiac Repair After Myocardial Infarction
Authors: Yasutomi Higashikuni, Kazuto Nakamura, Minoru Takaoka, Soichiro Enomoto, Hiroshi Iwata, Makoto Sahara, Kimie Tanaka, Masataka Sata, Ryozo Nagai
Journal: Circulation (2009)

Introduction Recently, the ATP-binding cassette transporter BCRP1/ABCG2 has been shown to regulate the function and survival of side population cells, which have been identified in various organs including heart and have stem cell properties. In addition, previous studies have revealed that BCRP1/ABCG2 is also expressed in endothelial cells of capillaries and arterioles in heart. This study was performed to clarify the role of BCRP1/ABCG2 in cardiac repair after myocardial infarction (MI). Methods and Results MI was induced in 8- to 12-week-old wild-type (WT) mice (n=51) and Bcrp1/Abcg2 knock-out (KO) mice (n=60) by ligating the left anterior descending artery. At 28 days after MI, the survival rate was significantly lower in KO mice than in WT mice (28.3% versus 74.5%, p=0.0001). The main cause of death in KO mice was cardiac rupture (CR) (67.4%), whereas CR was observed in only 30.8% among WT mice (p=0.019). Echocardiography showed that ventricular remodeling was more deteriorated in KO mice than in WT mice (left ventricular end-diastolic diameter, 5.16±0.31 mm versus 4.47±0.30 mm, p&lt;0.05; ejection fraction, 23.8±4.9% versus 32.9±5.8%, p=0.002), although baseline data did not differ between the two groups. The left ventricular end-diastolic pressure was more elevated in KO mice than in WT mice (10.7±4.1 mmHg versus 5.3±3.0 mmHg, p=0.006). Histological assessment revealed that myocyte hypertrophy and fibrosis in the non-infarcted area were exacerbated in KO mice compared with those in WT mice (myocyte cross-sectional area, 397.6±44.9 μ m 2 versus 312.7±27.1 μ m 2 , p&lt;0.05; collagen volume fraction, 3.8±1.2% versus 2.2±0.7%, p=0.008). Capillary density in the peri-infarction area at 5 days after MI was significantly reduced in KO mice than in WT mice as determined by anti-CD31 immunostaining (1033±188/mm 2 versus 1414±214/mm 2 , p=0.008). The number of macrophages (MΦs) and myofibroblasts (MFs), as identified by immunostaining for Mac-3 and α -SMA respectively, also decreased in KO mice than in WT mice (MΦs, 1359±251/mm 2 versus 1906±440/mm 2 , p=0.04; MFs, 1780±479/mm 2 versus 2582±330/mm 2 , p=0.007). Conclusions Cardiac repair after MI was impaired in KO mice. BCRP1/ABCG2 may play an important role in angiogenesis and in recruitment of MΦs and MFs after MI.
Abstract 5225: Coronary Vasospasm Induced in Transgenic Mice With Variant Phospholipase C- <i>δ</i> 1 (R257H)
Authors: Shuji Shibutani, Tomohiro Osanai, Toshihiro Ashitate, Takashi Echizen, Makoto Tanaka, Hirohumi Tomita, Takeshi Miwa, Hiroaki Matsubara, Ken Okumura
Journal: Circulation (2009)

We previously showed that the activity of phospholipase C (PLC)- δ 1, a key enzyme for Ca 2+ signaling in the coronary artery, was enhanced by 3 times in patients with coronary spastic angina (CSA) compared with control subjects, and it was positively correlated with coronary vasomotility. We further showed that structural mutation at 864G-A variant with the amino acid replacement of arginine 257 by histidine (R257H), was present in 10% of CSA patients and was related to enhanced PLC- δ 1 activity. However, no evidence was documented whether this variant directly and causatively contributes to the enhanced coronary vasomotility. We therefore examined the direct role of structural mutant PLC- δ 1 in the genesis of coronary spasm by generating the R257H variant PLC- δ 1 overexpressing transgenic (TG) mice. In TG mice, the introduced gene of human R257H variant PLC- δ 1 was expressed in overall vessels including the coronary arteries, and upregulated by 2 times compared with wild type (WT) littermate mice. Baseline blood pressure, heart rate, and body weight were similar between 20-week-old TG and WT mice. Ergonovine at 15, 50, and 80 mg/kg was injected through the carotid vein additively, and ECG was monitored continuously. The incidence of ST segment transient elevation was higher in TG mice than in WT after injection of ergonovine at 15 mg/kg (6/18 in TG vs 1/22 in WT, P&lt;0.05), 50 mg/kg (18/18 in TG vs 3/22 in WT, P&lt;0.01), and 80 mg/kg (18/18 in TG vs 11/22 in WT, P&lt;0.01). Concomitantly with the ST segment elevation, AV block or sinus bradycardia was observed. To further examine the morphological changes in the coronary artery, the microvascular filling technique was used in mice untreated with ergonovine. In TG mice, the decrease in coronary arteriole diameter at baseline was documented in the widespread area, although no change was found in WT mice. These suggest that overexpression of R257H variant PLC- δ 1 in the coronary artery causes coronary spasm at baseline and after ergonovine. The variant of PLC- δ 1 appears to be a therapeutic target for coronary spasm in CSA patients.
Abstract 5053: Deficiency of ASC (Apoptosis-associated Speck-like Protein Containing a Caspase Recruitment Domain) in Bone Marrow Cells Improved Myocardial Ischemia-Reperfusion Injury in Mice
Authors: Masanori Kawaguchi, Masafumi Takahashi, Takeki Hata, Yuichiro Kashima, Yasuko Takahashi, Junji Sagara, Shun’ichiro Taniguchi, Uichi Ikeda
Journal: Circulation (2009)

Background: Inflammatory responses play a key role in the pathophysiology of myocardial ischemia-reperfusion (I/R) injury. ASC is an adaptor protein that forms inflammasome whose activation leads to caspase-1-dependent interleukin (IL)-1 β generation and subsequent inflammatory responses; however, the role of ASC in myocardial I/R injury remains to be determined. Methods and Results: ASC deficient (ASC −/− ) and wild-type (WT) mice were subjected to 30 min LAD occlusion, followed by reperfusion. ASC −/− mice showed improved LV dysfunction (%FS: 34.0% vs. 25.7% at 14 days p&lt;0.01), reduced infarct area/area at risk (IA/AAR: 18.7% vs. 28.6% at 48 h, p&lt;0.01), and scar formation (scar/LV area: 9.7% vs. 14.6% at 14 days, p&lt;0.01) after myocardial I/R. Immunostaining revealed decreased infiltration of macrophages (Mac3) and neutrophils (Gr-1), but not neovascularization (CD31), in the injured myocardium of the ASC −/− mice. Real-time RT-PCR and ELISA analyses demonstrated that the myocardial mRNA and protein expression of inflammatory cytokines, such as IL-1 β , IL-6, and MCP-1, after I/R were significantly decreased in the ASC −/− mice. Further, improved myocardial I/R injury was also observed in the caspase-1 −/− mice, compared with WT mice (IA/AAR: 20.2% vs. 28.6% at 48 h, p&lt;0.05). Since double immunostaining revealed that ASC was expressed in the infiltrated macrophages and neutrophils, bone marrow-transplanted (BMT) mice were prepared. The IA/AAR was significantly decreased in the BMT ASC−/−→WT mice, compared with BMT WT→WT (IA/AAR: 17.8% vs. 27.9% at 48 h, p&lt;0.01). Further, in vitro experiments showed that LPS-induced production of inflammatory cytokines such as IL-1 β , IL-6, and MCP-1 in the ASC −/− -bone marrow cells was significantly decreased compared, with that in the WT-bone marrow cells. Conclusion: ASC deficiency improved myocardial I/R injury via inflammatory cell infiltration and cytokine expression. These results suggest that ASC is a novel therapeutic target for myocardial I/R injury.
Abstract 5137: Visualization of Accumulating Reactive Oxygen Species During Myocardial Ischemia by Real-time Two-photon Imaging of Perfused Rat Hearts
Authors: Moritake Iguchi, Masaharu Akao, Masashi Kato, Madoka Matsumoto-Ida, Takeshi Kimura, Toru Kita
Journal: Circulation (2009)

Background: During myocardial ischemia/reperfusion injury, a burst of reactive oxygen species (ROS) is considered to occur at the onset of reperfusion and cause cardiomyocyte death through the loss of mitochondrial membrane potential (ΔΨ m ), but there are evidences against this concept. We aimed to visualize the dynamic changes of ROS during ischemia/reperfusion in intact rat hearts using two-photon laser scanning microscopy. Methods and Results: Langendorff-perfused rat hearts were loaded with 5-(and -6)-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate acetyl-ester and tetramethylrhodamine ethyl-ester, fluorescent indicators of ROS and ΔΨ m , respectively. Under the two-photon excitation, spatio-temporal changes of ROS and ΔΨ m in response to ischemia/reperfusion were simultaneously monitored at cellular level. As soon as ischemia started, ROS level of each cell began to increase, despite maintained ΔΨ m . Importantly, the rate of ROS accumulation during the early phase of ischemia was variable from cell to cell, and irreversible ΔΨ m loss occurred in an all-or-none manner depending on cellular ROS level, with a clear cut-off value. Upon reperfusion, we were unable to detect a burst of ROS, but there were more cells undergoing similar ΔΨ m loss after the cell-to-cell specific period of latency. Importantly, there was a significant inverse correlation between the level of ROS accumulation during ischemia and the latency until which the cell underwent ΔΨ m loss (r=−0.89). Ischemic preconditioning delayed the increase of ROS during ischemia and protected against ΔΨ m loss. An iron chelator deferoxamine, which reduces the generation of hydroxyl radical through inhibiting the iron-mediated Fenton reaction, neither attenuated the ROS generation nor protected against ΔΨ m loss. A free radical scavenger N-(2-mercaptopropionyl)-glycine attenuated the ROS accumulation, but it did not protect against ΔΨ m loss. Conclusion: In myocardial ischemia/reperfusion, ROS are mainly generated during ischemia, but not after reperfusion, and play a critical role in mitochondrial collapse and cardiomyocyte death. However, reducing the ROS accumulation during ischemia may not suffice to prevent cell death.
Abstract 5113: Ablation of Lectin-like Receptor for Oxidized Low-density Lipoproteins (LOX-1) Resulted in Suppression of Ischemia-Induced Angiogenesis
Authors: Takeru Shiraki, Takuma Aoyama, Chiharu Yokoyama, Nishigaki Kazuhiko, Genzou Takemura, Takako Fujiwara, Hisayoshi Fujiwara, Tatsuya Sawamura, Shinya Minatoguchi
Journal: Circulation (2009)

Background: We previously identified LOX-1 as a receptor for oxidized low-density lipoproteins. Recent studies show LOX-1 contributes to capillary formation induced by Angiotensin II or oxLDL, suggesting the potential effects of LOX-1 on angiogenesis. Therefore, we elucidated whether LOX-1 might be involved in angiogenesis in ischemic hindlimb tissue. Methods and Results: Ischemia was surgically produced by femoral artery ligature in both wild-type mice (WT) and LOX-1 deletion mice (LOX-1 KO). The ratio of ischemic/nonischemic leg blood flow measured by laser Doppler perfusion imaging was significantly smaller in LOX-1 KO than WT on Day 14, 21 and 28 (p&lt;0.01). In agreement, histological capillary density (vWF immunostaining) was significantly lower in LOX-1 KO than in WT on Day 28 (115±28 vs. 177±19/HPF, p&lt;0.01). Next, we analyzed phosphorylation of p38 involved in LOX-1 signaling. Phosphorylation of p38 was suppressed in ischemic hindlimb tissue of LOX-1 KO mice compared with WT mice. Western blot analyses also showed remarkable induction of VEGF in hindlimb of WT on Day 3 after ischemia. On the other hand, ischemic tissues of LOX-1 KO contained very low VEGF, resulting in suppressed phospholylation of Akt and eNOS, which are downstream signaling of VEGFR2. Considering the fact that inflammation is important for ischemia-induced angiogenesis, we examined whether infiltrated macrophages (F4/80 immunochemistry) release VEGF in ischemic hindlimb using two-color immunofluorescence histochemical staining. Fewer numbers of macrophages infiltrated into the ischemic tissues in LOX-1 KO than in WT (64±24 vs. 118±25/HPF, p&lt;0.01), and immunohistochemical analysis revealed the number of infiltrated macrophages expressing VEGF was also decreased in LOX-1 KO (LOX-1: 34±19 vs. WT: 50±14/HPF, p&lt;0.01). Conclusions: This study demonstrates that LOX-1 deletion negatively modulates ischemia-induced angiogenesis through impairment of early inflammatory mononuclear cell infiltration, which releases VEGF. LOX-1 would become a novel target molecule for modulating angiogenesis in ischemic tissue.
Abstract 5160: Apelin Modulates Adipocyte and Inflammatory Cell Processes to Inhibit Atherosclerosis
Authors: Yoko Kojima, Ramendra Kundu, Nicholas J Leeper, Hyung J Chun, Thomas Quertermous
Journal: Circulation (2009)

Background: The G-protein coupled receptor APJ and its ligand apelin have many physiological roles in the cardiovascular system, although its overall impact and mechanism of effect on atherosclerosis remain controversial. Methods and Results: Apelin knockout male mice were bred with ApoE knockout (ApoE KO) mice to generate double knockout (DKO) mice. DKO and ApoE KO mice were fed a normal diet for 20 weeks, and atherosclerotic lesions were analyzed histologically in the aortic sinus and by en face analysis. DKO mice developed more atherosclerosis in the thoracoabdominal aorta than ApoE-KO mice (percent plaque area; 5.36±0.55 vs. 2.53±0.54, p&lt;0.05). Lesion area in the aortic sinus was also increased in DKO compared to ApoE-KO (0.30±0.14 vs. 0.15±0.04 mm2, p&lt;0.05). Histological analysis showed that there was no difference in macrophage or smooth muscle content between genotypes, and studies of reactive oxygen species also did not show a significant difference. Because of recent evidence that the apelin-APJ pathway modulates insulin action, we investigated metabolic parameters and those associated with insulin resistance in the mouse models. DKO mice had significantly greater body weight and fat weight, and glucose tolerance testing showed the DKO mice to be insulin resistant. Also, the mRNA expression of TNF-a, IL-6, and MCP-1 in visceral fat tissue was increased in DKO compared with ApoE KO mice. Similarly, in cultured NIH 3T3 cells, apelin treatment decreased LPS-induced MCP-1 mRNA expression. In related studies, we investigated macrophage function in a foam cell assay, and found there was increased CD36 mRNA in aorta, and increased oil red O positive staining cells in peritoneal macrophage preparations from DKO mice compared with those from ApoE-KO mice. Conclusion: Apelin-APJ signaling inhibits atherosclerosis through multiple mechanisms, including modulation of inflammation and metabolic effects in macrophages and adipose tissues.
Abstract 5218: Corrin-mediated Activation of Nitric Oxide Receptor and Its Cardiovascular Consequences
Authors: Emil Martin, Iraida G Sharina, Yang Yan Liang, Marie-Francoise Doursout
Journal: Circulation (2009)

Soluble guanylyl cyclase (sGC) is the recognized receptor for nitric oxide (NO) messenger molecule. In addition to NO, several allosteric regulators, which do not produce NO, can activate sGC heme-dependently or independently. Earlier studies recognized that tetrapyrrole protoporphyrin IX can actively replace sGC heme moiety or bind to the heme-deficient sGC, resulting in a robust activation of sGC ability to produce cGMP from GTP. We investigated the effects of various tetrapyrroles on the ability of sGC to generate cGMP in vitro. Our data demonstrated that not only various protoporphyrins but some corrins can activate sGC. Pro-vitamin B12 dicyanocobinamide (CN2-Cbi) was the most efficient among tested compounds. CN2-Cbi-dependent activation of sGC was synergistically enhanced by BAY41–2272, a heme-dependent allosteric regulator of sGC. CN2-Cbi and several other corrins, including vitamin B12, induces a dose-dependent relaxation on isolated rat aorta rings. Tested corrins were equally effective in endothelium competent or endothelium denuded rings. Effective concentrations of CN2-Cbi were significantly improved with BAY41–2272, and relaxation was achieved even with micromolar CN2-Cbi. Therefore, data are consistent with direct activation of sGC by CN2-Cbi. Following ex-vivo relaxation by CN2-Cbi, we monitored blood pressure (BP) in anesthetized rats in response to CN2-Cbi. CN2-Cbi (5 mg/kg bolus) induced a modest and transient decrease in BP while 15 mg/kg showed a more marked and prolonged response. Decreased BP was associated with increased cardiac output, suggesting vascular relaxation. CN2-Cbi combined with 100 μ g/kg BAY41–2272 induced a more profound and prolonged decrease in BP. Following U-46619, a thromboxane analogue to induce systemic and pulmonary hypertension, combined CN2-Cbi/BAY41–2272 was also effective in restoring systemic and pulmonary pressures to baseline. These data suggest that CN2-Cbi (or corrin)-mediated activation of sGC may be an alternative approach to regulate sGC activity and vascular function. Data indicate that derivatives of vitamin B12 may be used for regulation of BP in normal and hypertensive conditions as part or treatment regimens or dietary supplements.
Abstract 5054: Bone Marrow MyD88 Contributes to Ischemic Myocardial Infarction and Modulates Neutrophil Function and Chemokine Receptor Expression
Authors: Yan Feng, Lin Zou, Ri Si, Yasuko Nagasaka, Shiqian Shen, Wei Chao
Journal: Circulation (2009)

INTRODUCTION: MyD88 is an adaptor protein critical for innate immune signaling and plays a pivotal role in host defense against infection, but its role in non-infectious myocardial inflammation and injury after ischemia-reperfusion (I/R) is unclear. Our previous studies in MyD88 −/− (KO) mice have demonstrated that MyD88 is essential for I/R-induced myocardial injury. The current study was to delineate the specific contribution of cardiac and bone marrow (BM)-derived MyD88 in mediating ischemic cardiac injury and to explore the underlying mechanisms. METHODS: Chimeric models were generated by lethal irradiation and BM reconstruction. For I/R model, the coronary artery was ligated for 60 min and followed by reperfusion. At the end of reperfusion, the hearts were examined for ischemic and infarct sizes. To assess neutrophil mobility function, thioglycollate was injected intra-peritoneally. Six hours later, peritoneal cells were counted. Neutrophils were labeled with anti-Ly-6C and counted by flow cytometry. CXCR2 expression, which is critical for neutrophil mobility function, was measured by flow cytometry. RESULTS: There was a significant decrease in infarct sizes in KO compared to WT (22±1% vs. 37±2%, p &lt;0.001). Compared to WT→WT control (Donor→Recipient), KO→WT mice, which lacked MyD88 in BM cells but maintained intact MyD88 signaling in the heart, had smaller MI sizes ( p &lt; 0.05). Surprisingly, infarct sizes of WT→WT mice were also significantly reduced compared to WT ( p &lt; 0.05). To determine if MyD88 deficiency inhibits neutrophil function that contributes the observed cardiac benefit, we examined the neutrophil mobility and CXCR2 expression. Indeed, neutrophil mobility was dramatically decreased in KO mice compared to WT mice ( p &lt; 0.01). Neutrophil mobilization also decreased in WT→WT and KO→WT chimeric mice ( p &lt; 0.01). Moreover, there was a significant decrease in CXCR2 expression on the peritoneal neutrophils of KO and KO→WT mice ( p &lt; 0.01), but not in WT→WT mice. CONCLUSIONS: Taken together, these findings suggest that MyD88 signaling, most likely that of BM-derived neutrophils plays a critical role in mediating myocardial I/R injury. MyD88 may mediate I/R injury partly by modulating CXCR2 expression and thus neutrophil function. This research has received full or partial funding support from the American Heart Association, Founders Affiliate (Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, Vermont).