tbuckley/cabot-search huggingface dataset:
Abstract 5814: Vascular Lectin-Like-OxLDL Scavenger Receptor (LOX-1) Mediates Oxidative Stress, Endothelin-1, and Matrix Metalloproteinase Expression in the Vasculature of Vehicular Engine Emissions-Exposed Mice
Authors: Amie K Lund, JoAnn Lucero, Nadine Mathews, Melissa Harman, Selita’ Lucas, Matthew J Campen
Journal: Circulation (2009)

A positive correlation between exposure to traffic-related air pollution and increased rates of cardiovascular morbidity and mortality has been well documented; however, underlying mechanisms have not yet been elucidated. We have reported that vascular oxidative stress levels are significantly elevated in atherosclerotic apolipoprotein KO (ApoE−/−) mice exposed to vehicular emissions, which appears to mediate increases in vascular matrix metalloproteinases (MMPs) and endothelin-1 (ET-1), expression of which are associated with progression of atherosclerosis. Since ROS production promotes formation of oxidized LDL (oxLDL), we investigated whether the effects of oxLDL on the vasculature, in response to exposure to vehicular emissions, are mediated via the lectin-like-ox-LDL receptor (LOX-1). To test this hypothesis, 10 wk old male ApoE−/− mice on a high fat diet received either mouse IgG (control, 16 μ g protein/ml, 0.1 ml/mouse, i.p.) or the neutralizing antibodies to LOX-1 (anti-mouse LOX-1/SR-E1 antibody: 16 μ g protein/ml, 0.1 ml/mouse, i.p.) every other day. Mice were randomly assigned to inhalational exposure of either filtered-air (FA: n=12 anti-LOX-1, n=12 IgG) or a mixed exposure of 250 μ g PM/m 3 diesel exhaust + 50 μ g PM/m 3 gasoline engine exhaust (n=12 anti-LOX-1, n=12 IgG) for 6 hr/day for 7 days. Analysis showed significant elevations in oxLDL and aorta oxidative stress from mice exposed to vehicular exhaust compared to FA. Anti-LOX-1 treatment ameliorated the increase in circulating oxLDL, as well as vascular lipid peroxidation in vehicular exhaust-exposed animals. Aorta LOX-1, ET-1, MMP-9 and tissue inhibitor of MMPs, TIMP-1 and -2 mRNA expression, as well as MMP-9 protein and activity, were also observed to be significantly elevated with exposure to mixed vehicular exhaust, of which LOX-1, ET-1 and MMP-9 were attenuated through LOX-1 Ab treatment. In agreement with LOX-1 mRNA findings, LOX-1 protein and soluble LOX-1 (sLOX-1) plasma levels were also found increased in exposure animals. Such findings indicate that effects of ROS (and oxLDL), as well as expression of vascular factors associated with progression of atherosclerosis (ET-1 and MMPs), induced by vehicular exhaust exposure, are likely mediated through the LOX-1 receptor.
Abstract 5778: Protein Phosphatase 1 Signalling Pathway is Involved in the Control of Vascular Smooth Muscle Cells Proliferation
Authors: Lahouraria Hadri, Ioannis Karakikes, Elise Merlet, Anne-Marie Lompré, Evangelia Kranias, Roger J Hajjar, Larissa Lipskaia
Journal: Circulation (2009)

Protein phosphatase 1 (PP1), the main regulator of the transcription factor CREB, is strongly involved in the control of cell proliferation via p53 and p21. PP1 is regulated by phosphatase inhibitor-1 (I-1), which is activated by PKA phosphorylation and inhibited by protein phosphatase PP2A and PP2B (calcineurin). I-1 is expressed in vascular smooth muscle cells (VSMC), but does not appear to play a significant role in contractile or relaxant response We tested whether the I-1/PP1 pathway is involved in the control of VSMC proliferation Confocal immunofluorescence, Western blot analysis and real time PCR demonstrated that I-1 protein was expressed in the media layer of healthy human coronary and mammary arteries and down regulated in atherosclerotic vessels and proliferating human VSMC (1000 fold lower of mRNA). By contrast, PP1 expression was increased in proliferating human VSMC. Inhibition of I-1/PP1 signalling by siRNA PP1 or by adenoviral gene transfer of a constitutively active I-1 (I-1c) inhibited VSMC proliferation and migration in vitro. Promoter-reporter assay showed that in vitro I-1c gene transfer increased activity of CREB. Western blot analysis demonstrated that I-1c and siRNA PP1 increased phosphorylation of CREB, expression of p21, p53 and led to down regulation of cell cycle controlling proteins cyclin D1 and pRB. To assess the potential effect of I-1c gene transfer in the treatment of restenosis, we used a rat carotid artery injury model. I-1 was expressed in normal carotid artery but it was non-detectable two weeks after injury, which correlated with vascular remodelling during neointimal proliferation. Adenoviral gene transfer of I-1c prevented neointimal proliferation in the carotid injury model. In conclusion, the I-1/PP1 signalling pathway is involved in the control of VSMC proliferation and migration via the transcription factor CREB.
Abstract 5754: Rescue of Diabetes-Related Impairment of Angiogenesis by Gene Silencing of Thioredoxin-Interacting Protein
Authors: Louise L Dunn, Andrew Buckle, Philippa Simpson, Daniel Sieveking, Renee Chow, Patrick Lim, Martin Ng
Journal: Circulation (2009)

Objectives: Vascular complications of diabetes mellitus (DM) are associated with impaired angiogenesis, the mechanisms of which are poorly understood. The thioredoxin (TRX) system has been implicated in angiogenesis. Interestingly, thioredoxin-interacting protein (TXNIP), antagonist to TRX, is induced by glucose. We hypothesized that hyperglycemic-modulation of TXNIP/TRX plays a role in DM-impairment of angiogenesis. Methods: Endothelial cells (ECs) were cultured in 5–25 mM glucose and siRNA used to modulate the TXNIP/TRX system. EC migration, proliferation, tubulogenesis, TRX activity, VEGF, qPCR and protein were examined. Unilateral hindlimb ischemia was induced in a murine model of Type 1 DM. Txnip siRNA was delivered i.m. and limb perfusion assessed by laser Doppler, with ischemia, foot movement and capillary density also measured. Results: Hyperglycemia induced a dose-dependent inhibition of key angiogenic events including EC migration, proliferation and tubulogenesis (62.1Â±2.8%, 72.9Â±7.0% and 48.3Â±4.7% at 25 mM vs. control; P &lt; 0.05), with increased TXNIP expression (5.1Â±1.8-fold mRNA; 2.0Â±0.1-fold protein), enhanced TXNIP/TRX interaction and inhibition of TRX activity (59.8Â±4.8%; P&lt;0.001). TXNIP siRNA reversed the inhibitory effects of hyperglycemia on migration, proliferation, tubulogenesis and TRX activity to levels of control. DM was associated with a profound impairment of blood flow recovery following hindlimb ischemia (0.284Â±0.038 vs. 0.582Â±0.021; P&lt;0.001). However, i.m. delivery of Txnip siRNA dramatically increased limb perfusion in DM mice to levels not statistically different from control (0.443Â±0.047). Txnip siRNA also increased capillary density (2.0Â±0.4-fold), while ischemia and foot movement scores significantly improved in DM mice receiving Txnip siRNA (vs. DM control; P&lt;0.05). In both models, hyperglycemia/DM reduced VEGF expression and interfered with VEGF action, while TXNIP siRNA rescued VEGF levels to that of control. Conclusions: TXNIP plays a key role in angiogenesis and impaired neovascularization in DM, in part via modulation of VEGF. Our findings demonstrate that inhibition of TXNIP can abrogate the deleterious effects of hyperglycemia in angiogenesis.
Abstract 5775: C57BL/6 NK Cell Gene Complex Crucially Involved in General Vascular Remodelling
Authors: Leonard Seghers, Vincent van Weel, Jeroen van Bergen, Rene Toes, Alwine Hellingman, Margreet de Vries, Victor van Hinsbergh, Paul Quax
Journal: Circulation (2009)

Background The immune system plays an important role in vascular remodelling. Inflammatory cells as monocytes, CD4+ and CD8+ T cells were already proven to be modulators of vascular remodelling. Recently, NK cells were indicated to contribute to vascular remodelling in processes of revascularisation and atherosclerotic lesion development. Interestingly, C57BL/6 mice display profound induced vascular remodelling, eg in arteriogenesis, restenosis and vein grafting, whereas BALB/c mice display much less remodelling. Moreover, these two mouse strains are different in their NK cell receptor gene complex (NKC), which codes for activating and inhibitory NK cell receptors. Aim To demonstrate that C57BL/6 NKC is crucially involved in modulating vascular remodelling in general. Material &amp; Methods C57BL/6, BALB/c and BALB.B6- CMV1 r (CMV1 r ) mice, of which the latter is congenic for the C57BL/6 NKC, were used in two different models of vascular remodelling, induction of restenosis by femoral artery cuff placement and vein grafting by placement of a venous interposition in the mouse carotid artery. Vascular remodelling was monitored by morphometry and immunohistology. Results After cuff-placement the congenic CMV1r mice showed progressive formation of neointima (4745 um2), comparative to C57BL/6 (4459 um2), and significantly more than BALB/c mice (1247 um2), that displayed very little formation of neointima. Vein graft remodelling in CMV1 r mice showed stronger intimal hyperplasia in vein grafts (0.22mm2) compared to both C57BL/6 mice (0.15mm2) and BALB/c mice (0.11mm2). Importantly, CMV1 r displayed an inflammatory infiltrate similar to that of C57BL/6 mice, whereas BALB/c mice show hardly any inflammatory cell influx into the vessel wall. Conclusion These data demonstrate that the C57BL/6 NK cell gene locus is involved in the induction of profound vascular remodelling in general. Furthermore, the observed differences in inflammatory infiltrate between the three mouse strains strongly suggest that the C57BL/6 NK receptor repertoire might be involved in triggering an immune response that is associated with profound vascular remodelling.
Abstract 5753: An Axon-guiding Molecule Semaphorin3E is Critically Involved in Impaired Angiogenesis of Diabetes
Authors: Junji Moriya, Tohru Minamino, Kaoru Tateno, Sho Okada, Ippei Shimizu, Aika Nojima, Masataka Yokoyama, Issei Komuro
Journal: Circulation (2009)

The axon-guiding molecules known as semaphorins and their specific receptors (plexins) regulate the vascular pattern and play an important role in development of the vascular network during embryogenesis. However, it remains unclear whether these molecules are involved in postnatal angiogenesis. Here we report that semaphorin3E (Sema3E), one of the class 3 semaphorins, and its specific receptor plexinD1 inhibit angiogenesis in adults. Sema3E inhibited cell growth and tube formation by suppressing the vascular endothelial growth factor (VEGF) signaling pathway. Expression of Sema3E and plexinD1 was markedly up-regulated in ischemic limbs of mice, and inhibition of this pathway by introduction of the plexinD1-Fc gene or disruption of Sema3E led to significant improvement of revascularization. We also found that Sema3E-deficient mice showed better blood recovery and a larger vessel area in their ischemic limbs than wild-type mice, suggesting that Sema3E/plexinD1 negatively regulate postnatal angiogenesis. Next, we identified a putative binding element of p53, the tumor suppressor protein, within the promotor region of the Sema3E gene, and found that hypoxia up-regulated Sema3E expression by activating p53 in endothelial cells. Consistent with our in vitro data, up-regulation of Sema3E expression was abolished in the ischemic limbs of p53-deficient mice, suggesting that an increase of p53 promotes Sema3E expression in ischemic tissue and thus inhibits blood flow recovery. It has been reported that angiogenic response to ischemia is attenuated in diabetes. We found that expression of p53 was increased in diabetic mice and this increase was further enhanced by ischemia. Likewise, expression levels of Sema3E were significantly higher in diabetic mice than in control mice. Consequently, blood flow recovery after VEGF treatment was impaired in diabetic mice compared with VEGF-treated control mice. These changes were effectively reversed by additional introduction of the plexinD1-Fc gene. These results indicate that Sema3E negatively regulates postnatal angiogenesis and suggest that inhibition of Sema3E would be a novel strategy for therapeutic angiogenesis, especially when VEGF treatment is ineffective, such as in the diabetic state.
Abstract 5821: The Effect of Spironolactone on Biomarkers of Inflammation and Extracellular Remodelling in Early Chronic Kidney Disease
Authors: Nicola C Edwards, Helen Kirkwood, Robert Cramb, Colin A Hutchinson, Richard P Steeds, Charles J Ferro, John N Townend
Journal: Circulation (2009)

Introduction Early stage chronic kidney disease (CKD) is associated with major abnormalities of arterial and ventricular stiffness and function and with a high rate of adverse cardiovascular events. We have previously demonstrated that in this high risk group, significant reductions in LV mass and markers of arterial stiffness occurred after 40 weeks of treatment with the aldosterone antagonist, spironolactone. We hypothesized that serological markers of collagen turnover, inflammation and ventricular stress might also be improved with this treatment. Methods 112 patients participating in the double blind randomized controlled trial investigating the effect of spironolactone in early CKD had serum biomarkers of collagen turnover; amino-terminal propeptide of procollagen type III (PNIIIP), inflammation; high sensitivity C-Reactive Protein (hsCRP), and ventricular stress- N-terminal Pro Beta- Natriuretic Peptide (BNP) measured. Patients had stage 2 and 3 CKD, were on ACE Inhibitor or ARB therapy, with controlled hypertension (&lt;130/85mmHg) and no history of cardiovascular disease or diabetes. Samples were measured at baseline and after 40 weeks of blinded treatment with either spironolactone 25mg once a day or matching placebo. Results PNIIIP levels were unchanged with spironolactone but increased significantly in the placebo group (0.06 μ g/L±0.70 vs 0.46 μ g/L±0.82, p&lt;0.01). There was no difference in median hsCRP levels (0.01mg/L (IQR 1.63) vs. 0.08mg/L (IQR 2.76), p =NS). Spironolactone resulted in significant reduction in median BNP levels (−0.4pg/L (IQR 70.9) vs. 9.3pg/L (IQR 54.7), p&lt;0.01). All baseline biomarkers were positively correlated; PNIIIP with hsCRP ( r = 0.24, p&lt;0.05) PNIIIP and BNP ( r = 0.27, p&lt;0.01), hsCRP and BNP ( r = 0.39, p&lt;0.01). Conclusion Treatment with spironolactone prevents deterioration of or improves biomarkers of collagen synthesis and of ventricular stress in CKD. These data support the hypothesis that deleterious effects of aldosterone on extracellular remodeling can be attenuated by spironolactone in CKD as has been observed in clinical outcome studies of heart failure. The association of all biomarkers suggests a complicated interplay of collagen turnover, inflammation and myocyte stretch.
2009 Laennec Clinician/Educator Lecture—Diastolic Function: Past, Present, and Future
Authors: William Grossman
Journal: Circulation (2009)

One hundred years ago, research by Otto Frank, Carl Wiggers, and Yandell Henderson identified cardiac tonus and variable diastolic relaxation as important aspects of cardiac function. Belief in the existence of cardiac tonus and variable relaxation then went into eclipse from 1930 to 1970, during which time the application of A.V. Hill’s equations of muscle mechanics (derived from experiments on skeletal muscle) to cardiac physiology assumed that cardiac muscle was basically a “twitch” muscle and was completely passive between contractions. For the past 40 years, there has been a resurgence of interest in and experimental support for the concept of variable diastolic relaxation. At the same time, improved clinical measurement techniques have allowed simultaneous measurement of left ventricular pressure and volume, establishing firmly the existence and importance of rapidly occurring shifts in the diastolic left ventricular pressure–volume relation. Today, it is clear that up to 50% of patients presenting with acute heart failure manifest as pulmonary edema are exhibiting increased resistance to diastolic left ventricular filling as their primary problem, rather than impaired contractile function and reduced left ventricular systolic emptying. Many causes of increased resistance to diastolic left ventricular filling occur clinically, including myocardial hypertrophy, ischemia, diabetes, and increased coronary venous pressure, and may be modifiable with appropriate therapy. Examples will be presented.
Abstract 5813: Hyperhomocysteinemia Enhances Bone Marrow-derived and Vessel Resident Ly6C Inflammatory Monocyte Differentiation Contributing to Atherogenesis
Authors: Daqing Zhang, Xiaohua Jiang, Jodene K Moore, Remus M Berretta, Andrew I Schafer, Steven R Houser, William Durante, Xiaofeng Yang, Hong Wang
Journal: Circulation (2009)

Background: We recently reported that hyperhomocysteinemia (HHcy) enriched circulating Ly6C monocytes (MCs) independent of hyperlipidemia. Here we studied the effect and mechanism of HHcy on Ly6C MC function and differentiation in aorta. Methods and Results: We generated a mouse model with cystathionine β -synthase (CBS) and LDLr deficiencies. LDLr − / − CBS − /+ mice (8wk) received BM transplantation from EGFP mice. The chimeric mice were fed a high fat (HF) diet as control (Hcy, 10.1 μ M), HF/high methionine (HM) diet to induce severe HHcy (275.6 μ M), or HF/HM/high vitamin B-6/12 and folic acid diet as Hcy-lowering therapy (39.0 μ M) for another 8wk. Morphological analysis exhibited that severe HHcy accelerated atherosclerosis and increased BM-derived Ly6C MC accumulation in the lesion. FACS analysis on whole aortic cell suspension showed that severe HHcy increased BM-derived and resident putative MC (CD11b + Ly6G − ) to 4872 and 3761 from 1332 and 599 cells/aorta in the control. The putative MC was further divided into 4 distinct subsets, severe HHcy, compared with the control, increased BM-derived and resident Ly6C hi MC (Ly6C hi F4/80 − , 816 vs 43 and 842 vs 115), differentiating MC (Ly6C hi F4/80 + , 558 vs 43 and 784 vs 28), differentiated macrophage (Ly6C low F4/80 − , 1874 vs 766 and 1095 vs 92), and Ly6C low MC (Ly6C low F4/80 − , 1624 vs 480 and 1040 vs 365) in aorta. Plasma Hcy levels were significantly correlated with plasma TNF α (r=0.650), IL-6 (r=0.594) and MCP-1 (r=0.591) levels. Hcy-lowering therapy significantly reduced atherosclerotic lesion, plasma inflammatory cytokine levels and aortic MC differentiation. In vitro, L-Hcy (100 –500 μ M) enhanced IFN γ -induced Ly6C hi+mid MC differentiation, which was abolished by Tiron, SOD/catalase, and NADPH oxidase inhibitor apocynin. L-Hcy (500 μ M) increased the TNFa/IL-6 cytokine-producing Ly6C hi+mid MC by 3-fold in IFN γ -treated cells and significantly enhanced transendothelial migration of IFN γ -treated THP1 cells. Conclusions: Severe HHcy induces systemic inflammation and promotes BM-derived and vessel resident Ly6C inflammatory MC differentiation leading to exacerbated atherosclerosis. NADPH oxidase mediated oxidative stress participates in Ly6C inflammatory MC differentiation induced by Hcy.
Abstract 5751: High Glucose Induces Apoptosis in Endolthelial Cells via Epigenetic Regulation of Insulin-Like Growth Factor Receptor Expression
Authors: Yangxin Li, Yao-Hua Song, Jose G Diez, MacArthur A Elaydar, Hanjing Wu, Yong-Jian Geng
Journal: Circulation (2009)

High glucose-induced endothelial cell dysfunction is considered to be the main cause of the development of vascular complications in patients with diabetes. In this study, we examined the effect of high glucose (HG) on apoptosis of human umbilical vein endothelial cells (HUVEC) and investigated the molecular mechanisms involved. HUVEC was exposed to HG and apoptosis was assessed by Death ELISA. Our data showed that HG induced significant apoptosis in HUVEC cells after exposing to HG for 5 days (O.D. value = 0.36±0.07 in HG group vs. 0.13±0.05 in control, p&lt;0.05). HG induced apoptosis in HUVEC is associated with decreased of insulin-like growth factor receptor (IGF-1R) mRNA (4.1±0.6 fold at 72 h, p&lt;0.05) as assessed by real-time PCR and IGF-1R protein (3. 1±0.5 fold at 96 h, p&lt;0.05) as assessed by western blot, which were dose- and time-dependent effects (25 mM of glucose rather than 5 mM at 72 h and 96 h). The effects of HG on reduced expression of IGF-1R and apoptosis were blocked by silencing histone deacetylase 1 (HDAC1) with small interference RNA (siRNA-HDAC1) compared to non-targeting scrambled siRNA. Moreover, HG negatively regulated IGF-1R promoter activity as determined by ChIP (chromatin immunoprecipitation) analysis, which was dependent on HDAC1 since siRNA-HDAC1 attenuated the effects of HG on IGF-1R promoter activity. HG also increased the association of IGF-1R promoter with HDAC1, and decreased the association of IGF-1R promoter with acetylated histone-4. Furthermore, trichostatin A, a specific HDAC inhibitor, relieved the repression of IGF-1R and prevented apoptosis of HUVEC following HG state. These results suggest that HG-induced repression of IGF-1R is mediated by the association of HDAC1 with the IGF-1R promoter, and by the subsequent reduced recruitment of chromatin-modifying proteins, such as histone 4 to the IGF-1R promoter. In conclusion, our data demonstrate that high glucose exposure decreases expression of IGF-1R and decreases the association of acetylated histone-4 with the IGF-1R promoter, and suggest that enhancing acetylation of histone 4 and IGF-1R expression may be a useful strategy to prevent diabetic-induced apoptosis of endothelial cells. This research has received full or partial funding support from the American Heart Association, South Central Affiliate (Arkansas, New Mexico, Oklahoma &amp; Texas).
Abstract 5802: Ischemia-induced Angiogenesis is Impaired in Aminopeptidase-A deficient Mice with Decreased Stability of HIF-1 <i>α</i>
Authors: Ryuji Kubota, Yasushi Numaguchi, Masakazu Ishii, Keiji Naruse, Kenji Okumura, Toyoaki Murohara
Journal: Circulation (2009)

Background: Aminopeptidase A (APA) is a membrane-bound metalloprotease degreading bioactive peptidase by cleaving from N-terminal amino acids with several functions in angiogenesis. To assess whether APA regulates ischemia-induced angiogenesis, we explored the mechanism by which APA affects angiogenesis under hypoxia conditions and evaluated the process of perfusion recovery in the hindlimb ischemia model of APA knock-out mice (APAKO). Methods and Results: Western blotting analysis and immunostaining of endothelial cells (ECs) from mouse aorta revealed that the accumulation HIF-1 α protein and nuclear translocation in response to hypoxic challenge (1%O 2 , 12h) were blunted in APAKO (HIF-1 α / β -Actin ratio, C57BL/6J (WT) vs APAKO: 0.987±0.069 vs 0.467±0.063, mean±SE, p=0.018). Although the levels of E3 ubiquitin ligase Siah2 and prolyl-hydroxylase 3 (PHD3), both upstream regulators of HIF-1 α , did not alter under hypoxia (1%O 2 , 6h), proteasome inhibitor MG-132 restored the decreased accumulation of HIF-1 α in ECs from APAKO similar to WT. Tube formation assay under hypoxia showed ECs of APAKO formed significantly less endothelial network (Tube length, mm/field, WT vs APAKO: 35.2±3.4 vs 27.6±5.0, p=0.024), and this was partly reversed by VEGF (50ng/mL) treatment (31.2±4.8, p=0.048), but not by soluble APA peptide supplementation (26.6±4.3, p=NS). APAKO and WT mice were subjected to unilateral hindlimb ischemia. Laser Doppler perfusion imaging demonstrated decreased blood flow recovery in APAKO, (Ischemic/Non ischemic limb, WT vs APAKO: 0.80±0.07 vs 0.70±0.04, at 4 weeks, p=0.046). Tissue capillary density at 2 weeks was significantly decreased in APAKO (ECs/Muscle Ratio, WT vs APAKO: 1.57±0.15 vs 1.25±0.12; p=0.039). FACS analysis of endothelial progenitor cells revealed no significant difference between in APAKO and WT mice, suggesting that vasculogenesis was minimally involved in the reparative process from ischemia in APAKO mice. Conclusion: Ischemia-induced angiogenesis is impaired in APAKO mice due to decreased stability of HIF-1 α with upregulation of proteasomal degradation under hypoxic conditions and subsequent shortage of growth factor secretion. APA would be a functional target of ischemia-induced angiogenesis.