bluuebunny/crossref_metadata_2025 huggingface dataset:
2006 Sol Sherry Distinguished Lecture in Thrombosis—Crosstalk Between the Hemostatic and Inflammatory Systems
Authors: Degen Jay
Published: April 2024

Essentially all of the major coagulation and fibrinolytic system components (including proteases, co-factors, receptors, inhibitors, and substrates) have been experimentally eliminated or functionally altered in gene-targeted mice. Detailed studies of these mutant animals have greatly improved the understanding of the role of these proteins in complex physiological and pathological processes in vivo. Hemostatic derangements were the most predictable consequence of genetically imposed alterations in key coagulation and fibrinolytic factors, but more detailed studies have illuminated another less obvious aspect of the hemostatic system—namely, that coagulation and fibrinolytic factors appear to figure prominently into a wide spectrum of biological processes in vivo that have little or nothing to do with traditional hemostasis. Studies of mice with hemostatic deficits compatible with survival to adulthood (eg, fibrinogen-, plasminogen activator–, and plasminogen-deficient mice) have revealed an important role of these factors in phenomenally diverse biological settings (eg, immune surveillance, neurodegeneration and repair, tumor metastasis, and inflammatory diseases). Regulatory crosstalk between the hemostatic and inflammatory systems has become an increasingly frequent biological theme. The precise mechanisms by which thrombin, fibrinogen, and other hemostatic factors contribute to the inflammatory response remain to be fully defined, but leukocyte receptor interactions with fibrin(ogen) and other hemostatic factors are likely to be one important means of locally regulating leukocyte function. A comprehensive understanding of the role of hemostatic factors in inflammatory processes may suggest new strategies for the treatment of a wide array of inflammatory diseases.
2006 George E. Brown Memorial Lecture—The CYP450 Pathway and Cardioprotection
Authors: Gross Garrett
Published: April 2024

Ischemia-reperfusion of the heart and other organs results in the accumulation of unesterified arachidonic acid (AA) via the action of membrane-bound phospholipases, primarily phospholipase A
2
. AA can be metabolized by the classical cyclooxygenase (COX) and lipoxygenase (LOX) pathways to well-characterized metabolites and their respective cardioprotective end products such as prostacyclin (PGI
2
) and 12-hydroxyeicosatetraenoic acid (12-HETE); however, it has only been recently recognized that another less well-characterized pathway of AA metabolism, the cytochrome P450 (CYP) pathway, may have important cardiovascular effects. Several lines of data support the possibility that certain CYP metabolites resulting from the hydroxylation of AA, such as 20-hydroxyeicosatetraenoic acid (20-HETE), are potent vasoconstrictors and may produce detrimental effects in the heart during ischemia and proinflammatory effects during reperfusion. On the other hand, a group of regioisomers resulting from the epoxidation of AA, including 5,6-, 8,9-, 11,12- and 14,15-epoxyeicosatrienoic acid (EETs), have been shown to reduce ischemic and/or reperfusion injury in the heart and other organs. In this presentation, I will discuss the detrimental and beneficial actions of this novel pathway, including the potential cellular mechanisms responsible for the effects observed as a result of stimulating or inhibiting the 2 arms of this novel CYP450 pathway. The therapeutic potential of increasing EET concentrations and/or reducing 20-HETE concentrations will also be addressed.
2006 Donald Seldin Lecture—Molecular Genetics of Cardiovascular Risks: The Kidney as the Cause of Hypertension
Authors: Lifton Richard
Published: April 2024

Hypertension affects 1 billion people worldwide and is a major contributor to death from myocardial infarction, stroke, congestive heart failure, and kidney failure. Its pathogenesis has been unknown because of the complexity of blood pressure regulation, and only a minority of patients is adequately treated. To identify key pathways involved in long-term determination of blood pressure, we have investigated rare families from around the world in which hypertension or hypotension show evidence of transmission via the effects of a single gene. Using molecular genetic analysis, we have identified the specific genes and mutations that cause these disorders and have determined their biochemical mechanisms of action. These include mutations in 9 genes that cause hypertension and 8 that cause hypotension. These genes converge on a final common pathway that regulates renal salt homeostasis; mutations that cause increased renal salt reabsorption raise blood pressure, whereas those that reduce salt reabsorption lower blood pressure. Mutated genes include those encoding ion channels and transporters that mediate or regulate salt reabsorption, enzymes and receptors that regulate production of aldosterone and transduction of its signal, and a novel family of serine-threonine kinases that regulate diverse flux pathways to coordinate the balance between renal salt reabsorption and K
+
secretion. These studies demonstrate the key role of renal salt handling in determination of blood pressure and identify promising new targets for therapeutic intervention. Moreover, they underscore the importance of reduction of salt balance in the treatment of hypertension in the general population while revealing limitations of single-agent diuretic therapies.
2009 George L. Duff Memorial Lecture—The Toll of Toll-Like Receptors on Atherosclerosis
Authors: Curtiss Linda
Published: April 2024

Atherosclerosis is an inflammatory disease. Atherosclerotic lesions are foci of vessel wall inflammation. Lesions begin, very early in life, as fatty streaks, progressing to vulnerable obstructive lesions under the influence of both genetic and lifestyle insults. During a human lifetime that elapses between fatty streak formation and overt disease, many events can accelerate lesion progression. Genetic diseases, notably hypercholesterolemia, lead to severe disease. Lifestyle choices, which include smoking, obesity, and excessive quiescence, also make significant contributions to disease progression. Finally, inflammatory disease elsewhere in the body, ranging from periodontitis to autoimmune disease, can have an exacerbating effect as well. Toll-like receptors are a key mechanistic link between chronic inflammation and atherosclerosis. However, the factors that promote atherosclerotic lesion development do not do so uniformly throughout the arterial tree.

Lesions form first at sites of disturbed blood flow. Such sites are at vessel bifurcations and at the lesser curvature of the aortic arch. These sites display an inflamed phenotype even in the absence of any other exacerbating disease factors. This is due to the altered flow patterns at these sites within the aortic arch and the endothelial cell response to this disturbed flow. The biochemical mechanisms by which endothelial cells detect flow patterns are beginning to be understood. However, no particular atherosclerosis risk factor has been identified that would promote a proinflammatory phenotype only at arterial bifurcations and the lesser curvature of the aortic arch. Toll-like receptors (TLRs) may provide a clue.

TLRs are initiators of inflammation driven by agonists that can be either endogenous, such as sterile tissue damage, or exogenous, such as pathogens. Given the vicissitudes of daily life, TLRs likely initiate appropriate inflammatory responses every day. The majority of these are beneficial, promoting healing and homeostasis, but occasionally, inappropriate TLR activation causes pathology.

Bone marrow transplantation experiments demonstrate that leukocytes do not participate in the early atheroprotective inflammatory responses observed in TLR-deficient mice exposed to only endogenous agonists, but do participate in the proatherogenic responses to an exogenous agonist. We hypothesize that the exacerbation of disease progression mediated by endogenous activation of TLR receptors in endothelial cells is a disease of the arteries that is an “inside-out” (blood–lumen–endothelial cell–intima) phenomenon. In contrast, the accelerated disease mediated by exogenous activation of TLR receptors on circulating leukocytes is an “inside-out” and an “outside-in” disease phenomenon (leukocytes–vasa vasorum–adventia to media).
2009 Thomas W. Smith Memorial Lecture—GRK2 Inhibition as a Novel Therapeutic Target in Heart Failure
Authors: Koch Walter
Published: April 2024

For more than 15 years, our laboratory has been researching the role of the G protein–coupled receptor kinases (GRKs) in myocardial function. This includes how GRKs are involved in the cardiovascular pathological processes of hypertension, ventricular hypertrophy, and heart failure. Studies with GRK2 (also known as
β
ARK1) have shown, from cell studies to whole-animal studies, that the increased activity of this kinase is pathological to the cardiomyocyte. Importantly, lowering its expression or activity has led to beneficial effects in several animal models of heart failure. Most recently, studies in myocyte-specific GRK2-knockout mice have revealed that the loss of GRK2 in heart cells prevents the development of heart failure after a myocardial infarction. In separate animal studies, gene therapy with a GRK2 inhibitor peptide has shown that lowering the activity of this kinase can reverse ventricular contractile failure and also adverse remodeling. Large animal preclinical studies are being done with gene therapy; however, development of small-molecule inhibitors of GRK2 is warranted. This lecture will focus on the translational continuum of research for the past 15+ years in the development of GRK2 as a definitive target for heart failure therapy. The lecture will also include new data supporting unique roles for GRK2 in myocardial signaling and function.
2009 Robert Levy Memorial Lecture—LDL and Atherosclerosis: What Simple Genetics Tell Us About a Complex Disease
Authors: Cohen Jonathan
Published: April 2024

Complex diseases result from interactions among multiple genetic and environmental factors. We have used DNA sequencing in individuals with extreme phenotypes to identify low-frequency alleles with large effects on gene function. This strategy has revealed that mutations with large effects on protein function are more common than was previously recognized and can provide important insights into phenotype and mechanism. By screening candidate genes involved in low-density lipoprotein metabolism, we identified sequence variants present in 2% to 3% of individuals in the general population that cause moderate (15% to 30%) reductions in low-density lipoprotein levels yet confer substantial protection against coronary heart disease. This finding suggests that complex diseases may not be so complex, either in etiology or prevention.
Kynurenine Is a Novel Contributor to Hypotension in Human Sepsis
Authors: Changsirivathanathanathamrong Dechaboon
Published: April 2024

Abstract #2366

Dechaboon Changsirivathanathanathamrong, Yutang Wang, Ctr for Vascular Res, Bosch Inst, Sydney, Australia; Dorrilyn Rajbhandari, Royal Prince Alfred Hosp, Sydney, Australia; Ghassan Maghzal, Ctr for Vascular Res, Bosch Inst, Sydney, Australia; Clive Woolfe, Royal Prince Alfred Hosp, Sydney, Australia; Val Gebski, NHMRC Clinical Trials Ctr, Sydney, Australia; David S Celermajer, Royal Prince Alfred Hosp, Bosch Inst, Sydney, Australia; Roland Stocker, Ctr for Vascular Res, Bosch Inst, Sydney, Australia

Dechaboon Changsirivathanathanathamrong, 2009 Finalist and Presenting Author
Arterial Spin Labeling MRI Quantifies the Recovery of Myocardial Perfusion During Infarct Healing in Mice
Authors: Vandsburger Moriel H
Published: April 2024

Abstract #253

Moriel H Vandsburger, Robert L Janiczek, Yaqin Xu, Brent A French, Craig H Meyer, Christopher M Kramer, Frederick H Epstein, Univ of Virginia, Charlottesville, VA

Moriel H Vandsburger, 2009 Finalist and Presenting Author
Left Ventricular Hypertrophy Patterns and the Incidence of Heart Failure: The Framingham Heart Study
Authors: Velagaleti Raghava S
Published: April 2024

Abstract #898

Raghava S Velagaleti, Michael J Pencina, Framingham Heart Study - NHLBI, Framingham, MA; Jayashri Aragam, Veterans Admin Hosp, West Roxbury, MA; Thomas J Wang, Daniel Levy, Ralph B D’Agostino, William B Kannel, Emelia J Benjamin, Ramachandran S Vasan, Framingham Heart Study - NHLBI, Framingham, MA
Giant Left Ventricular Aneurysm as a Late Complication of Inferior Myocardial Infarction
Authors: Alenghat Francis J.
Published: April 2024

Abstract #3079

Francis J. Alenghat, Michael M. Givertz, Brigham & Women’s Hosp, Boston, MA

Francis J. Alenghat, 2009 Finalist and Presenting Author
Notifiable Genetic Variants on Commercially Available SNP Arrays: Implications for Research Participants in Genome-wide Association Studies For Cardiovascular Disease
Authors: Johnson Andrew D
Published: April 2024

Abstract #1806

Andrew D Johnson, NHLBI’s The Framingham Heart Study, Framingham, MA; Anupama Bhimavarapu, Harvard Medical Sch, Cambridge, MA; Emelia J Benjamin, Boston Univ, Boston, MA; Caroline Fox, Daniel Levy, NHLBI’s The Framingham Heart Study, Framingham, MA; Gail P Jarvik, Washington Univ, Seattle, WA; Christopher J O’Donnell, NHLBI’s The Framingham Heart Study, Framingham, MA

Andrew D Johnson, 2009 Finalist and Presenting Author
Vitamin A Status Regulates Glucose and Lipid Homeostasis in Rats
Authors: Chen Guoxun
Published: April 2024

Abstract #1146

Guoxun Chen, Wei Chen, Rui Li, Yan Zhang, Univ Tennessee Knoxville, Knoxville, TN

Guoxun Chen, 2009 Finalist and Presenting Author
Abstract 4762: Cessation of Rivaroxaban in Post-ACS Patients is Not Associated With Clinical Evidence of Rebound Hypercoagulability: An ATLAS ACS-TIMI 46 Substudy
Authors: Mega Jessica L , Braunwald Eugene , Lee Mary , Misselwitz Frank , Mohanavelu Satishkumar , Notani Ravi , Peters Gary , Gibson C. Michael
Published: April 2024

Introduction
: In vitro and outcome studies suggest that rebound hypercoagulability is present after cessation of some anticoagulants. Rivaroxaban is an oral, direct factor Xa inhibitor that has been shown to reduce major atherothrombotic events in post-ACS patients. Whether rivaroxaban is associated with rebound hypercoagulability in this population remains undefined.

Methods
: ATLAS ACS-TIMI 46 randomized post-ACS patients to placebo or rivaroxaban (5–20 mg) for 6 mos, with a 30 day follow-up visit. This analysis included 3367 subjects with ≥1 day follow-up after last study drug administration. Cox regression was used to assess the risk of events (primary: death, MI, stroke, or severe recurrent ischemia requiring revascularization; secondary: death, MI, or stroke) within 10 days of cessation of study drug.

Results
: Among subjects who completed the treatment period (N=2808), cessation of rivaroxaban and placebo was associated with a similar rate of the primary (HR 1.03, 95% CI 0.19–5.64) and secondary (HR 0.77, 95% CI 0.13–4.64) endpoints. Moreover, among subjects who discontinued study drug early (N±559), there were no significant differences in the risk of events after cessation of rivaroxaban and placebo (Figure

). Overall (N=3367), the risk of death or cardiovascular events after discontinuation of study drug was similar with rivaroxaban and placebo (primary: HR 1.28, 95% CI 0.59–2.77; secondary: HR 1.11, 95% CI 0.51–2.44).

Conclusion
: In post-ACS patients, discontinuation of rivaroxaban as compared with placebo is not associated with an increase in death or cardiovascular events, and thus there does not appear to be clinical evidence of rebound hypercoagulability.
Abstract 4840: Are Statins Nephroprotective? A PCI Study to Explore for Possible Pleiotropism
Authors: Ivanova Valentyna , Spotti Jennifer , Lasorda David M , Vido Diane A , Grant Saundra B , Biederman Robert W
Published: April 2024

HMG-CoA reductase inhibitors (statins) are used for dyslipidemia treatment and CAD prevention. Considerable controversy exists regarding statins’ possible pleiotropic effect with many vascular and nonvascular beds benefiting from their use. However, little data exists to support possible nephroprotective statins effect or their potential for ‘nephro-pleiotropism’.

Hypothesis
We hypothesize that pre-administration of statins in patients prior to undergoing percutaneous coronary intervention (PCI) may be beneficial in preventing contrast induced nephropathy (CIN) due to a pleiotropic effect.

Methods
A retrospective study of >4000 patient charts who underwent PCI for routine clinical reasons was performed. Pts who developed CIN were selected based on serum creatinine (SCr) level elevation by ≥0.5mg/dL from baseline and further stratified into statin use (+/−) prior to PCI and by LDL level.

Results
SCr was measured within 1 week prior to or on day of PCI in 805 pts: 516 (64%) male, 289 (36%) female and within 1 week post PCI. Statin therapy was initiated in 328 (41%) pts ≥1 week prior to PCI. When classified by statin use (+/−), there was no difference in incidence of CIN (29 vs 39, p=0.8). However, there was a significant number of pts with SCr rise to >2.5mg/dL in the statin(−) group (p<0.05). When limited to absolute rise in SCr, the mean rise in SCr was 0.64 in statin(−) vs 0.16mg/dL in statin(+) subgroup, representing a 3-fold nephroprotective effect of statins (p<0.001). Via multivariate analysis, neither age, gender, HTN, DM or contrast load was a significant predictor for the rise in SCr. In 44 pts (16 statin(+), 28 statin(−)) with recent LDL levels there was no difference in the mean LDL (99 vs 91mg/dL respectively, p=NS) and this pattern held true when categorized by LDL <70, <100, or <130mg/dL (p=NS for all), again independent of all defined comorbidities.

Conclusions
Pre-PCI administration of statins is strongly nephroprotective. Multivariate analysis demonstrates the 3-fold nephroprotection is independent of common clinical high risk comorbidities. A more controversial finding implicates the lack of a direct anti-atherosclerotic LDL lowering effect as the genesis since LDL levels were nearly
superimposable,
implying substantial pleiotropism.
Abstract 4843: Furosemide-induced Diuresis With Matched Replacement of Intravascular Volume Compared to Standard Hydration for Contrast-induced Nephropathy Prevention: The Mythos Trial
Authors: Marenzi Giancarlo , Ferrari Cristina , Assanelli Emilio , Marana Ivana , Lauri Gianfranco , De Metrio Monica , Grazi Marco , Teruzzi Giovanni , Trabattoni Daniela , Bartorelli Antonio L
Published: April 2024

Hypothesis.
We investigated the effect of a new preventive strategy strategy for contrast-induced nephropathy (CIN) based on a dedicated device (RenalGuard; PLC Medical System Inc., USA). The system is capable of delivering i.v. saline solution to a patient in an amount matched to the volume of urine produced after an i.v. bolus of furosemide. The aim of the study was to evaluate if furosemide-induced high-volume diuresis with concurrent maintenance of intravascular volume may prevent CIN.

Methods
. To date, 63 chronic kidney disease (CKD) patients (eGFR<60 ml/min/1.73 m
2
) undergoing percutaneous coronary interventions (PCI) were enrolled in the MYTHOS trial. They were randomized to matched hydration (RenalGuard group, n=30) or to i.v. isotonic saline hydration (control group; n=33) at a rate of 1 ml/kg/hour for 12 hours before and after PCI. Matched fluid replacement was started approximately 90 minutes pre-PCI, maintained during catheterization, and for up to 4 hours afterwards. Patients were given an initial i.v. bolus of 250 ml of normal saline over 30 minutes and then an i.v. bolus of furosemide (0.5 mg/kg). The RenalGuard measures the patient’s urine volume and then automatically adjusts the infusion pump rate to precisely replace the measured urine output in real time. When a >300 ml/hour urine output rate was obtained, patients underwent PCI. CIN was defined as a ≥0.5 mg/dl or ≥25% rise in serum creatinine over baseline.

Results
. Overall, the mean eGFR was 40±9 ml/min/1.73 m
2
. The mean contrast volume was 190±92 ml in RenalGuard group and 212±118 ml in controls (P=0.4). In RenalGuard group, urine output ranged from 319 to 1788 ml/hr (mean 830±322 ml/hr). There were no serious device-or therapy-related complications, including clinically significant electrolyte changes (asymptomatic ipokalemia was corrected in 1 case). CIN occurred in no patient (0%) of the RenalGuard group and in 5 (15%) controls (P=0.03). Two controls (6%) required temporary renal replacement therapy.

Conclusions.
These preliminary results indicate that furosemide-induced high urine output with maintenance of intravascular volume through matched hydration can be safely obtained with the RenalGuard system and may reduce the risk of CIN in CKD patients undergoing PCI.
Abstract 4845: Control of Notch Signaling by Reversible Acetylation Through the Antagonistic Activities of p300/PCAF and SIRT1 in Endothelial Cells
Authors: Guarani Virginia , Dequiedt Franck , Schmidt Mirko H , Zeiher Andreas M , Dimmeler Stefanie , Potente Michael
Published: April 2024

Signaling by Notch receptors is a key cell-cell communication mechanism essential for development and homeostasis of the cardiovascular system. Several critical steps of angiogenic blood vessel growth are coordinated by the Notch pathway and even subtle perturbations in Notch activity can profoundly influence endothelial cell behavior and blood vessel growth, yet very little is known about the dynamics and intrinsic regulation of endothelial Notch signaling. Here, we show that reversible acetylation regulates the amplitude and duration of Notch responses by altering protein turnover of the Notch1 intracellular domain (NICD) in endothelial cells. We report that the histone acetyltransferases (HATs) p300 and PCAF not only acetylate nucleosomal histones at Notch target promoters, but also the NICD itself. Acetylation of NICD induced by p300 and PCAF results in increased NICD stability and enhanced Notch target gene expression. Likewise, blocking histone deacetylase (HDAC) activity using the class III HDAC inhibitor nicotinamid (NAM) leads to a substantial increase in NICD acetylation while class I/II HDAC inhibition has no significant effect suggesting that class III HDACs primarily target NICD for deacetylation. Among the class III HDACs with deacetylase activity (SIRT1, 2, 3, 5), specifically SIRT1 associates with NICD through its catalytic domain and silencing of SIRT1 enhances NICD acetylation. Wild type SIRT1, but not a catalytically inactive mutant catalyzes the deacetylation of NICD in a nicotinamid-dependent manner indicating that SIRT1 acts as a direct NICD deacetylase, which counteracts HAT-induced NICD acetylation. Inactivation of SIRT1 by NAM or RNAi-mediated knock down results in enhanced NICD protein stability by blocking proteasomal degradation. Consistent with these results, knock down of SIRT1 amplifies Notch target gene expression in endothelial cells in response to NICD overexpression or treatment with the Notch ligand Delta-like 4 (Dll4). Taken together, these findings support a model, in which Notch signaling is dynamically regulated by reversible acetylation and suggest that the antagonistic activities of p300/PCAF and SIRT1 act as rheostat to fine-tune endothelial Notch responses.
Abstract 4847: COUP-TFII Inhibits Expression of Transcription Factor Hey2 in Human Arterial Endothelial Cells
Authors: Korten Slobodanka , Goettsch Winfried , Morawietz Henning
Published: April 2024

Normal development of an organism requires formation, differentiation and stabilization of blood vessels. Furthermore, many diseases have their origin in disturbed arterial and venous function, e.g. coronary artery disease, peripheral arterial occlusive disease or deep-vein thrombosis. Arteries and veins differ not only in their physiology, but also in their structure. We identified two transcription factors specifically expressed in venous (COUP-TFII) or in arterial endothelial cells (Hey2). In this study, we analyzed a potential direct molecular interaction of these two determinants of an arterial and venous phenotype. Using lentiviral gene transfer, we overexpressed venous marker gene COUP-TFII in human primary arterial endothelial cells. Using this approach, we reached high transduction efficiency of HUAEC. We were able to show, that the overexpressed transcription factor COUP-TFII was correctly processed and transported into the nucleus. More importantly, COUP-TFII overexpression caused downregulation of arterial marker gene Hey2. These data suggested that COUP-TFII could be a direct repressor of Hey2. Using two independent methods, chromatin immunoprecipitation and electrophoretic mobility shift assay, we can show that COUP-TFII binds to the Hey2 promoter thus repressing its activity. This was confirmed by COUP-TFII supershift strongly supporting a direct interaction of COUP-TFII with the Hey2 promoter. In conclusion, using lentiviral gene transfer allowing efficient and stabile transduction of primary endothelial cells, we were able to show that the venous marker gene COUP-TFII downregulates the expression of the arterial marker gene Hey2 in primary arterial endothelial cells. Additional analysis confirmed that the transcription factor COUP-TFII directly binds to specific sites of the Hey2 promoter, thus leading to the downregulation of its expression. This is a novel molecular mechanism defining an arterial or venous phenotype in human endothelial cells.
Abstract 4848: Angintensin II Stimulates Microtubule Reorganization Mediated by SIRT2 in Endothelial Cells
Authors: Komatsu Aiko H , Hirase Tetsuaki , Asaka Machiko , Node Koichi
Published: April 2024

Angiotensin II has been implicated in the pathophysiology of vascular remodeling. Microtubule composed of tubulins regulates cell shape, migration and survival. Tubulin acetylation plays an important role in the control of microtubule structure and microtubule-based cellular functions. We studied angiotensin II-induced changes in microtubules in endothelial cells. Immunofluorescence microscopy showed that acetylated tubulin was decreased in PECAM-1-positive cells in the intima of the aortic walls in mice loaded with angiotensin II, compared to mice loaded with control vehicle. In cultured human endothelial cells in quiescence,
α
-tubulin-positive microtubules were acetylated and showed radial layout from microtubule-organizing center to peripheral edge of cells. Angiotensin II induced disassembly and deacetylation of
α
-tubulin, which were blocked by pretreatment with losartan that is an angiotensin II type 1 receptor blocker, sirtinol that is an inhibitor for sirtuin class deacetylases, and depletion of a deacetylase SIRT2 by RNA interference. We investigated the involvement of SIRT2 in angiotensin II-induced endothelial cell migration using Boyden chamber method. Angiotensin II caused a significant increase in cell migration, which was blocked by pretreatment with sirtinol and SIRT2 depletion. It has been reported that angiotensin II is involeved in cytoskeletal reorganization stimulated by mechanical stretch in endothelial cells. To investigate the effects of mechanical stretch on microtubule reorganization, cultured endothelial cells were subjected to 10% uniaxial stretch and examnied by immunofluorescence. Mechanically stretched cells showed vertical alignment to tension direction and tubulin deacetylation in peripheral side of cells, compared to control static cells. Mechanical stretch-induced changes of microtubules were blocked by pretreatment with sirtinol and SIRT2 depletion. These data suggest that angiotensin II and mechanical stretch stimulate microtubule redistribution and deacetylation via SIRT2 in endothelial cells. Further studies are necessary to elucidate the roles of SIRT2-mediated microtubule reorganization in vascular remodeling.
Abstract 4868: A Third Troponin Sample is Not Cost-effective in Patients Suspected of Acute Coronary Syndrome
Authors: Al-Zuhairi Karam Sadoon Majeed , Hjortshøj Søren , Kristensen Søren R , Ravkilde Jan
Published: April 2024

Objective The American Heart Association, the American College of Cardiology, and the European Society of Cardiology joint Task Force guidelines from 2007 suggest that troponins, which is the preferred cardiac biomarker in diagnosing acute myocardial infarction (MI), should be assessed by blood sampling at admission and 6 –9 hours later. In many institutions, a third blood sample 12–24 hours after admission is routinely drawn. The aim of the present study was to evaluate cost-effectiveness of this third blood sample of troponin.

Methods We investigated 534 patients who were admitted with chest pain and suspected acute coronary syndrome (ACS). Blood samples for cardiac troponin T (cTnT) analysis were obtained on arrival, after 6 –9 hours, and after 12–24 hours. Acute MI was defined according to the universal definition of MI, with cTnT above 99th percentile, given a coefficient of variability of < 10%. For cost-benefit calculation, total costs per patient were estimated as: One additional cTnT analysis (USD 15) + prolonged hospital stay (0.5 day × USD 1,000).

Results Of 534 patients admitted with suspected ACS, 124 patients (23 %) had at least one increased cTnT value. Among these only 4 patients (3.2 %) had cTnT values increased in the third blood sample while the first two samples were normal (p < 0.003). All 4 patients were eligible to be referred to coronary angiography due to their risk profile and electrocardiographic changes even before the result of the third sample became available.

Cost-benefit analysis: Incremental costs in our hospital, attributed to the third cTnT sample, can be calculated as: (534 × USD 15 per cTnT sample) + (534−124 pts × 0.5 day × USD 1,000) = USD 213,010. Approximately 1,400 patients with suspected ACS are admitted to our department per year. Thus, the total incremental cost per year is: (1,400/534) × USD 213,010 = USD 558,453.

Conclusion: A third blood sample to measure cTnT should not be performed as it adds no further important information regarding the patient’s treatment or investigations plan. On the contrary, it leads to an unnecessary extension of the hospital stay and increased costs.
Abstract 4878: Role of Mitochondrial Superoxide in Endothelial Dysfunction and Hypertension
Authors: Dikalova Anna E , Bikineyeva Alfiya T , Budzyn Klaudia , Nazarewicz Rafal R , Lewis William , Harrison David G , Dikalov Sergey
Published: April 2024

Background.
Superoxide (O

2
−

•
) production by vascular NADPH oxidase is strongly implicated in the pathogenesis of hypertension; however, the role of mitochondrial O

2
−

•
is not clear. In this work we have investigated the role of mitochondrial O

2
−

•
in endothelial dysfunction and hypertension in cultured human aortic endothelial cells and in hypertensive mice using mitochondria-targeted superoxide dismutase mimetic mitoTEMPO, depletion or overexpression of mitochondrial superoxide dismutase (SOD2).

Results.
We found that supplementation of AngII-stimulated endothelial cells with mitoTEMPO decreased AngII-stimulated mitochondrial O

2
−

•
, inhibited production of cellular O

2
−

•
, restored nitric oxide (NO), attenuated c-Src activity and inhibited NADPH oxidase. SOD2 plasmid increased SOD activity in mitochondria but not in the cytoplasm, however, it inhibited cytoplasm NADPH oxidase and blocked AngII-induced cellular O

2
−

•
. SOD2 depletion with siRNA increased both basal and AngII-stimulated cellular O

2
−

•
due to higher NADPH oxidase activity while mitoTEMPO treatment mimicked SOD2 overexpression. Infusion of mitoTEMPO to AngII-treated mice attenuated AngII-induced hypertension. mito-TEMPO treatment after the onset of hypertension decreased blood pressure by 30 mm Hg both in AngII-infused and DOCA-salt mice (Table 1

). The antihypertensive effect of mitoTEMPO was accompanied by decreased vascular O

2
−

•
, increased vascular NO production and recovery of endothelial-dependent relaxation. Interestingly, mice transgenic for mitochondrial SOD2 demonstrated attenuated AngII-induced hypertension and vascular oxidative stress similar to mitoTEMPO supplementation (Table 1

).

Conclusion.
Our data show that mitochondrial O

2
−

•
is important for regulation of vascular NADPH oxidase and it represents a novel therapeutic target to treat endothelial dysfunction and hypertension.

Table 1.

Antihypertensive effect of mitoTEMPO (mT) and SOD2 overexpression (mm Hg)

This research has received full or partial funding support from the American Heart Association, National Center.
Abstract 4881: Depletion of the Endothelial Nitric Oxide Synthase (eNOS) Substrate NADPH Triggers Endothelial Dysfunction in the Post-Ischemic Heart: Role of Glucose 6 Phosphate Dehydrogenase (G6PD)
Authors: Reyes Levy A , Dumitrescu Cristian , Druhan Lawrence , Zweier Jay L
Published: April 2024

Reperfusion injury causes dysfunction in the coronary vascular endothelium; however, current understanding of this process is incomplete. Delineation of the mechanisms involved is critical for advancing treatment of myocardial infarction. Previously, we showed that endothelial dysfunction is triggered by loss of the eNOS cofactor, tetrahydrobiopterin (BH
4
), and BH
4
repletion partially restored endothelial-dependent vasodilation. We hypothesize that the oxidative stress induced by ischemia/reperfusion (I/R) injury may also result in loss of the essential eNOS substrate NADPH, which is also utilized for BH
4
resynthesis, thus impairing eNOS function. We observe in the isolated rat heart that NADPH declines by ~70% after 30 min I and 30 min R (from 0.41±0.02 to 0.13±0.04
μ
M/gram tissue, by HPLC, n=4, p<0.01). The importance of this NADPH depletion was demonstrated by the marked rescue of coronary flow, with 80.0±4.0% increase, following NADPH repletion (175
μ
M liposomal formulation infused for 10 min) in hearts subjected to 30 min of I and R. Further studies were performed to understand the mechanism of NADPH depletion. In the presence of oxidative stress, NADPH is rapidly oxidized and glucose 6 phosphate dehydrogenase (G6PD), is required for its regeneration. We observe that myocardial G6PD activity was decreased ~43% during ischemia (Table

), but this activity partially recovered after 30 min R. Interestingly, with addition of excess exogenous glucose-6-phosphate (G6P) the activity did not significantly change from control levels after 30 min of I and after 30 min R only a modest 20% fall was seen (Table

). Thus, the ability of G6PD to resynthesize NADPH remained largely intact but was limited by lack of its substrate G6P. In conclusion, we found that repletion of NADPH post ischemia results in a near total restoration of endothelial dependent coronary flow, and that ischemic depletion of G6P may be partially responsible for the limited bioavailability of NADPH.

Glucose-6-Phosphate Dehydrogenase Enzyme Activity
Abstract 4893: Selective Aldosterone Blocker Enhances Protective Effects of Calcium Channel Blocker (CCB) Against Salt-sensitive Hypertension-induced Cardiovascular Injury, Independently of Blood Pressure
Authors: Nakamura Taishi , Kataoka Keiichiro , Fukuda Masaya , Nako Hisato , Toyama Kensuke , Ogawa Hisao , Kim-Mitsuyama Shokei
Published: April 2024

Purpose
: The effects of aldosterone blocker against hypertension (HTN)-induced cardiovascular injury are still unclear.

We compared the protective effects of eplerenone (EPL), an aldosterone blocker and amlodipine (AML), a CCB on salt-sensitive HTN-induced cardiovascular injury,

and examined these combined effects on cardiovascular protection.

Methods
: Dahl salt-sensitive rats fed on 8% NaCl containing diet were divided into vehicle, EPL (100mg/kg), AML (10mg/kg), and EPL combined with AML.

Results
:

EPL monotherapy, without affecting blood pressure (BP) and plasma renin activity, significantly suppressed HTN-induced cardiac macrophage infiltration and interstitial fibrosis, coronary arterial remodeling, and improved HTN-induced vascular endothelial dysfunction, to a similar extent to strongly BP lowering AML.

Beneficial effects of the combination therapy against HTN-induced cardiac inflammation, fibrosis, and vascular endothelial dysfunction were greater than AML monotherapy despite no lowering BP. Moreover, combination of EPL and AML markedly improved HTN-induced cardiac diastolic dysfunction compared with vehicle.

These additive amelioration by the combination against hypertensive cardiac injury compared with AML monotherapy were associated with more attenuation of cardiac MCP-1, IL-6 and TGF-
β
1 expressions, and more reduction of cardiac superoxide partially derived from NADPH oxidase. Furthermore, improvement of vascular endothelial dysfunction by the combination compared with AML monotherapy was attributed to not only more reduction of vascular NADPH oxidase-mediated superoxide but also more increase of NO by vascular endothelial NO synthase phosphorylation. It is interesting that the amelioration of endothelial fucntion by EPL was associated with the attenuation of HTN-induced vascular apoptosis signal-regulating kinase 1 (ASK1) activation. Actually, we found that vascular ASK1 deficiency markedly reduced vascular superoxide, and improved vascular endothelial dysfunction caused by aldosterone/salt-induced HTN in ASK1 deficient mice.

Conclusions
: Without lowering BP, aldosterone blocker enhanced protective effects of CCB against salt sensitive HTN-induced cardiovascular injury.
Abstract 4896: White-coat Hypertension and Left Ventricular Hypertrophy: Findings From the HARVEST Study
Authors: Mos Lucio , Visentin Pieralberto , D’este Daniele , Dorigatti Francesca , Martina Stefano , Vriz Olga , Santonastaso Massimo , Palatini Paolo
Published: April 2024

White-coat hypertension (WCH) is considered a benign clinical condition, but recent studies indicate that patients with WCH may be at increased risk of events. Aim of this study was to evaluate the risk of left ventricular hypertophy (LVH) in this hypertension category in the population of HARVEST study: 470 never-treated young adults (330 men) with a mean age of 33.8 ± 8.5 years (range, 18 to 45 years), who were screened for stage 1 hypertension on at least two occasions, were enrolled. Patients were seen every six months for clinic blood pressure ( BP) and global risk assessment to determine which subjects developed hypertension needing drug therapy (HT). Echocardiographic left ventricular mass (LVM) and 24h ambulatory blood pressure (ABP) were measured at entry, every 5 years, and/or at the time of HT development before starting treatment. Subjects were divided according to whether they had WCH (n = 184) or sustained hypertension (SH, n = 286) at baseline. ABP and LVM measured at baseline and at the end of follow-up were used for analysis. LVH was defined as a LVM ≥50 g/m2.7 in men and ≥47 g/m2.7 in women.

Results. During a 8.5 year follow-up, similar percents of subjects developed LVH (WCH, 8.2% vs SH, 6.3%, p = n.s.). LVM increased by 1.8 ± 6.4 g/m2.7 in WCH and by 0.7 ± 6.9 g/m2.7 in SH (p adjusted for age, sex, BMI, baseline LVM, and time = n.s.). ABP from baseline to study-end rose by 7.9 ± 10.8/5.6 ± 7.2 mmHg in WCH and by 1.2 ± 10.9/1.9 ± 7.9 mmHg in SH (adjusted p for WCH vs SH < 0.000). WCH had a greater increase in ABP than SH also from the 3-month to the study-end measurement (+ 6.2 ± 9.7/4.3 ± 8.2 vs 2.4 ± 12.3/2.8 ± 8.6 mmHg, p = 0.009 for systolic BP, and p = 0.02 for diastolic BP). When data were adjusted also for baseline ABP, no significant difference emerged between WCH and SH for all comparisons.

Conclusions. A greater increase in ABP and body weight and a similar susceptibility to develop LVH was observed in WCH compared to SH, suggesting that WCH should not be regarded as a benign condition. This implies an increased risk of cardiovascular events and prompts for a more tight clinical control along with target organ surveillance in WCH subjects.
Abstract 4917: Peptide-based Antibodies Against Glutathione-binding Domains Suppress Superoxide Production Mediated by Mitochondrial Complex I
Authors: Chen Jingfeng , Chen Chwen-Lih , Chen Chun-An , Kaumaya Pravin P , Zweier Jay L , Chen Yeong-Renn
Published: April 2024

Complex I (NQR) is a critical site of superoxide (O
2
•−
) production and the major host of reactive/regulatory protein thiols in mitochondria. In response to oxidative stress, NQR-derived protein thiols at the 51 kDa and 75 kDa subunits are known to be reversibly S-glutathiolated. Although several glutathiolated domains from NQR 51 kDa and 75 kDa have been identified, their role in the catalytic and regulatory function remain to be determined. To gain further insights into protein S-glutathiolation of complex I in myocardial ischemia and reperfusion, we used two S-glutathiolated peptides (
200
GAGAYI
C206
GEETALIESIEGK
219
of 51-kDa protein and
361
VDSDTL
C367
TEEVFPTAGAGTDLR
382
of 75-kDa protein) as chimeric epitopes incorporating a “promiscuous” T cell epitope to generate two polyclonal antibodies, AbGSC206 and AbGSC367. Binding of AbGSC206 and AbGSC367 inhibited NQR-mediated O
2
•−
generation by 37% and 57%, as measured by EPR spin-trapping with DEPMPO. To further provide an appropriate control, two non-glutathiolated peptides (
21
SGDTTAPKKTSFGSLKDFDR
40
of 51-kDa and
100
WNILTNSEKTKKAREGVMEFL
120
of 75-kDa) were synthesized as chimeric epitopes to generate two high titer polyclonal antibodies, Ab51 and Ab75. Binding of A51 did not affect NQR-mediated O
2
•−
generation. However, binding of A75 inhibited NQR-mediated O
2
•−
generation by 35%. None of AbGSC206, AbGSC367, Ab51, or Ab75 showed an inhibitory effect on the electron transfer activity of NQR, suggesting that antibody binding to the GS-binding domain decreased electron leakage for superoxide generation mediated by complex I. Purified Ab51 and Ab75 showed high immunological specificity to the NQR of rat myocardial tissue and the mouse cardiac myocyte HL-1 cell line. Rats were subjected to 30 min of coronary ligation followed by 24 hours of reperfusion. When tissue homogenates were immunoprecipitated with Ab51 or Ab75 and probed with an antibody against glutathione, protein S-glutathiolation was enhanced by 60.8±5.7% (
p
<
0.05, n
=
6)
in the post-ischemic myocardium at the NQR 51 kDa subunit, but not significantly changed at the NQR 75 kDa subunit, suggesting that the NQR 51 kDa subunit is more sensitive to oxidative stress caused by myocardial infarction.
Abstract 4922: Epoprostenol Induces Apoptosis By Inhibiting The Expression Of Survivin In Pulmonary Artery Smooth Muscle Cells
Authors: Akagi Satoshi , Nakamura Kazufumi , Kusano Kengo , Matsubara Hiromi , Ito Hiroshi
Published: April 2024

Background: Pulmonary arterial hypertension (PAH) is associated with suppressed apoptosis of pulmonary artery smooth muscle cells (PASMCs). Survivin has been reported to suppress caspase activities and plays an important role in the mechanism of suppressed apoptosis. In this study, we investigated whether epoprostenol exerts the pro-apoptotic effects by inhibiting the expression of survivin in PASMCs.

Methods: We studied the induction of apoptosis by epoprostenol in PAH-PASMCs (n = 5) and non-PAH-PASMCs (n = 3). We investigated the expression of survivin in lung tissues obtain from 5 idiopathic PAH patients and 3 non-PAH patients, and in PAH-PASMCs and non-PAH-PASMCs by immunocytochemical analysis. We examined the protein level of survivin in PAH-PASMCs treated with epoprostenol or diluents by western blotting. We also examined the time course of mRNA level of survivin treated with epoprostenol or diluents by quantitative RT-PCR.

Results: TUNEL-positive cells, caspase-3- and -7-active cells, condensation of chromatin along the nuclear membrane, and fragmentation of the nucleus were found in PAH-PASMCs treated with epoprostenol. Epoprostenol significantly induced apoptosis in PAH-PASMCs compared with that in non-PAH-PASMCs (5.64 ± 0.82% versus 0.64 ± 0.25%; P < 0.05). Survivin was expressed in lung tissues obtained from idiopathic PAH patients but not from non-PAH patients. Survivin was also expressed in PAH-PASMCs but not non-PAH-PASMCs with immunocytochemical analysis. Treatment with epoprostenol for 24 hours significantly suppressed the protein level of survivin by 52% compared with treatment with diluents in PAH-PASMCs (P < 0.05). Epoprostenol significantly decreased the mRNA level of survivin after 12 hours (29%; P < 0.05) and 24 hours (10%; P < 0.05) treatment compared with diluents.

Conclusions: Epoprostenol can induce the apoptosis by inhibiting the expression of survivin in PAH-PASMCs.
Abstract 4925: TGF-
β
Downregulates PPARgamma Gene Expression in Pulmonary Arterial Smooth Muscle Cells (PASMCs): Novel Mechanism of Hypoxia-induced Pulmonary Vascular Remodeling
Authors: Li Peng , Gong Kaizheng , Lucas Jason , Zhang Yun , Yang Qinglin , Oparil Suzanne , Chen Yiu-Fai
Published: April 2024

Introduction:
Pharmacologic activation of PPAR
γ
in lung has been shown to attenuate pulmonary arterial remodeling and fibrosis associated with hypoxic pulmonary hypertension. We previously have shown that transforming growth factor (TGF)-
β
plays a critical role in hypoxia-induced pulmonary vascular remodeling and fibrosis. The current study tested the novel hypotheses that endogenous PPAR
γ
gene expression is downregulated in lung exposed to chronic hypoxia and in PASMCs treated with TGF-
β
.

Methods:

In vivo: 10 wk old male Sprague-Dawley rats were exposed to 10% O
2
for 2 wks. PPAR
γ
protein levels in lung were assessed using Western blot analysis.

In vitro: Rat PASMCs were transfected with a plasmid including PPAR
γ
promoter and a luciferase reporter gene and then exposed to TGF-
β
1 (1 ng/ml) for 24 hrs. PPAR
γ
promoter activity and mRNA levels were assessed using luciferase activity and real time qRT-PCR analyses.

Results
: 2-wk hypoxic exposure significantly decreased PPAR
γ
protein levels in lung. TGF-
β
1 treatment decreased PPAR
γ
promoter activity and mRNA levels in PASMCs (Figure

).

Conclusion
: These provocative findings indicate that TGF-
β
inhibits expression of PPAR
γ
, a putative endogenous anti-fibrogenic transcription factor, in PASMCs. This observation, coupled with the finding that chronic hypoxic exposure decreases PPAR
γ
in lung, suggests that TGF-
β
-induced downregulation of PPAR
γ
in PASMCs represents a novel mechanism of hypoxia-induced pulmonary vascular remodeling and fibrosis. The interaction between TGF-
β
and PPAR
γ
signaling pathways at this level may play an important role in modulating the pro-fibrogenic response of lung to hypoxic exposure.

This research has received full or partial funding support from the American Heart Association, Greater Southeast Affiliate (Alabama, Florida, Georgia, Louisiana, Mississippi, Puerto Rico & Tennessee).