Faculty Bibliography

The aim of the present study is to explore the role of capillary disorder in coronary ischemic congestive heart failure (CHF). CHF was induced in rats by aortic banding plus ischemia-reperfusion followed by aortic debanding. Coronary arteries were perfused with plastic polymer containing fluorescent dye. Multiple fluorescent images of casted heart sections and scanning electric microscope of coronary vessels were obtained to characterize changes in the heart. Cardiac function was assessed by echocardiography and in vivo hemodynamics. Stenosis was found in all levels of the coronary arteries in CHF. Coronary vasculature volume and capillary density in remote myocardium were significantly increased in CHF compared with control. This occurred largely in microvessels with a diameter of ≤3 μm. Capillaries in CHF had a tortuous structure, while normal capillaries were linear. Capillaries in CHF had inconsistent diameters, with assortments of narrowed and bulged segments. Their surfaces appeared rough, potentially indicating endothelial dysfunction in CHF. Segments of main capillaries between bifurcations were significantly shorter in length in CHF than in control. Transiently increasing preload by injecting 50 μl of 30% NaCl demonstrated that the CHF heart had lower functional reserve; this may be associated with congestion in coronary microcirculation. Ischemic coronary vascular disorder is not limited to the main coronary arteries, as it occurs in arterioles and capillaries. Capillary disorder in CHF included stenosis, deformed structure, proliferation, and roughened surfaces. This disorder in the coronary artery architecture may contribute to the reduction in myocyte contractility in the setting of heart failure.

BACKGROUND:Alternatively spliced tissue factor (asTF) is a novel isoform of full-length tissue factor, which exhibits angiogenic activity. Although asTF has been detected in human plaques, it is unknown whether its expression in atherosclerosis causes increased neovascularization and an advanced plaque phenotype. METHODS AND RESULTS/RESULTS:Carotid (n=10) and coronary (n=8) specimens from patients with stable or unstable angina were classified as complicated or uncomplicated on the basis of plaque morphology. Analysis of asTF expression and cell type-specific expression revealed a strong expression and colocalization of asTF with macrophages and neovessels within complicated, but not uncomplicated, human plaques. Our results showed that the angiogenic activity of asTF is mediated via hypoxia-inducible factor-1α upregulation through integrins and activation of phosphatidylinositol-3-kinase/Akt and mitogen-activated protein kinase pathways. Hypoxia-inducible factor-1α upregulation by asTF also was associated with increased vascular endothelial growth factor expression in primary human endothelial cells, and vascular endothelial growth factor-Trap significantly reduced the angiogenic effect of asTF in vivo. Furthermore, asTF gene transfer significantly increased neointima formation and neovascularization after carotid wire injury in ApoE(-/-) mice. CONCLUSIONS:The results of this study provide strong evidence that asTF promotes neointima formation and angiogenesis in an experimental model of accelerated atherosclerosis. Here, we demonstrate that the angiogenic effect of asTF is mediated via the activation of the hypoxia-inducible factor-1/vascular endothelial growth factor signaling. This mechanism may be relevant to neovascularization and the progression and associated complications of human atherosclerosis as suggested by the increased expression of asTF in complicated versus uncomplicated human carotid and coronary plaques.

BACKGROUND:Smooth muscle cell (SMC) migration and proliferation critically influence the clinical course of vascular disease. We tested the effect of the novel small leucine-rich repeat protein podocan on SMC migration and proliferation using a podocan-deficient mouse in combination with a model of arterial injury and aortic explant SMC culture. In addition, we examined the effect of overexpression of the human form of podocan on human SMCs and tested for podocan expression in human atherosclerosis. In all these conditions, we concomitantly evaluated the Wnt-TCF (T-cell factor) pathway. METHODS AND RESULTS/RESULTS:Podocan was strongly and selectively expressed in arteries of wild-type mice after injury. Podocan-deficient mice showed increased arterial lesion formation compared with wild-type littermates in response to injury (P<0.05). Also, SMC proliferation was increased in arteries of podocan-deficient mice compared with wild-type (P<0.05). In vitro, migration and proliferation were increased in podocan-deficient SMCs and were normalized by transfection with the wild-type podocan gene (P<0.05). In addition, upregulation of the Wnt-TCF pathway was found in SMCs of podocan-deficient mice both in vitro and in vivo. On the other hand, podocan overexpression in human SMCs significantly reduced SMC migration and proliferation, inhibiting the Wnt-TCF pathway. Podocan and a Wnt-TCF pathway marker were differently expressed in human coronary restenotic versus primary lesions. CONCLUSIONS:Podocan appears to be a potent negative regulator of the migration and proliferation of both murine and human SMCs. The lack of podocan results in excessive arterial repair and prolonged SMC proliferation, which likely is mediated by the Wnt-TCF pathway.

Drugs are designed for therapy, but medication-related adverse events are common, and risk/benefit analysis is critical for determining clinical use. Rosiglitazone, an efficacious antidiabetic drug, is associated with increased myocardial infarctions (MIs), thus limiting its usage. Because diabetic patients are often prescribed multiple drugs, we searched for usage of a second drug ("drug B") in the Food and Drug Administration's Adverse Event Reporting System (FAERS) that could mitigate the risk of rosiglitazone ("drug A")-associated MI. In FAERS, rosiglitazone usage is associated with increased occurrence of MI, but its combination with exenatide significantly reduces rosiglitazone-associated MI. Clinical data from the Mount Sinai Data Warehouse support the observations from FAERS. Analysis for confounding factors using logistic regression showed that they were not responsible for the observed effect. Using cell biological networks, we predicted that the mitigating effect of exenatide on rosiglitazone-associated MI could occur through clotting regulation. Data we obtained from the db/db mouse model agreed with the network prediction. To determine whether polypharmacology could generally be a basis for adverse event mitigation, we analyzed the FAERS database for other drug combinations wherein drug B reduced serious adverse events reported with drug A usage such as anaphylactic shock and suicidality. This analysis revealed 19,133 combinations that could be further studied. We conclude that this type of crowdsourced approach of using databases like FAERS can help to identify drugs that could potentially be repurposed for mitigation of serious adverse events.

Ultrasound assessment of vascular biomarkers has been implemented for screening, prevention and improvement of cardiovascular risk stratification beyond classical risk factors including smoking, diabetes, hypercholesterolemia and hypertension. Thus, the presence of vascular damage at the sub-clinical, asymptomatic stages can identify a "vulnerable" patient, and aid in implementing cardiovascular prevention strategies. Increased intima-media thickness of the common carotid artery is a well-known marker of early atherosclerosis, which significantly correlates with the development of coronary or cerebro-vascular disease. More recently, guidelines for cardiovascular prevention in hypertension also introduced other vascular parameters evaluating both mechanical and functional arterial properties of peripheral arteries. Increased arterial stiffness, which can be detected by ultrasound at the common carotid, has been shown to predict future cardiovascular events and it is already considered a subclinical target organ of hypertensive patients. Even earlier vascular abnormalities such as endothelial dysfunction in the peripheral arteries, detected as reduced flow-mediated dilation of the brachial artery by ultrasound, have also been mentioned for their possible clinical use in the future. This manuscript reviews clinical evidence supporting the use of these different vascular markers for cardiovascular risk stratification, focusing on the need for an accurate, robust and reliable methodology for the assessment of vascular markers, which could improve their predictive value and increase their use in routine clinical practice.

OBJECTIVE:To evaluate local carotid stiffness (CS) and intima-medial thickness (C-IMT) in hypertensive patients with different cardiovascular risk profile, using a new user-friendly ultrasound-based system, previously validated vs. RF-based echotracking device. METHODS:We investigated a population with different cardiovascular risk: 45 healthy normotensives (NT), 90 non-diabetic hypertensives (HT), and 48 patients with hypertension and type-2 diabetes (DM). Framingham risk factor score (FRS) was calculated. PWV was assessed by applanation tonometry. The relative stroke change in diameter (ΔD) and C-IMT were measured on carotid scans. Distensibility coefficient (DC) was calculated as ΔA/(A*ΔP), where A = diastolic lumen area, ΔA = stroke change in lumen area, and ΔP = carotid pulse pressure. CS (m/s) was calculated as (ρ*DC) - 1/2 (ρ = blood density). RESULTS:CS, C-IMT, PWV were significantly increased in HT and DM vs. NT. C-IMT and PWV were significantly higher in DM than HT. ΔD and DC were significantly lower in HT and DM vs. NT. FRS ≥10% group showed increased carotid diameter, C-IMT and CS than the FRS <10%. FRS was (p < 0.001) correlated with CS (r = 0.35); ΔD (r = -0.36), DC (r = 0.35), C-IMT (r = 0.48), PWV (r = 0.38). CS correlated (p < 0.05) with PWV in the entire population (r = 0.37), in the NT (r = 0.35), in the HT and DM (r = 0.20). PWV (r = 0.50) and CS (r = 0.33) were correlated with age. Determinants of aortic and carotid stiffness were identified by multivariate stepwise analysis. CONCLUSIONS:The proposed B-mode ultrasound-based system is a reliable and user-friendly method that could serve to investigate the predictive value of CS for cardiovascular events in future large clinical studies.

OBJECTIVE:The aim of this study was to compare the effects of HDL(Milano) and HDL(wild-type), on regression and stabilization of atherosclerosis. METHODS:Atherosclerotic New Zealand White rabbits received 2 infusions, 4 days apart, of HDL(Milano) (75mg/kg of apoA-I(Milano)), HDL(wild-type) (75mg/kg apoA-I(wild-type)) or placebo. Pre- and post-treatment plaque volume was assessed by MRI. Markers of plaque vulnerability and inflammation were evaluated. Liver and aortic cholesterol content, aortic ABCA-1 and liver SR-BI were quantified. The effect of apoA-I Milano and wild-type proteins on MCP-1 and COX-2 expression by macrophages was evaluated in vitro. RESULTS:Both forms of HDL induced aortic plaque regression (-4.1% and -2.6% vs. pre-treatment in HDL(Milano) and HDL(wild-type) respectively, p<0.001 and p=0.009). A similar reduction in cholesterol content of aorta and liver was observed with both treatments vs. placebo. The expression of aortic ABCA-1 and hepatic SR-BI was significantly higher in both treated groups vs. placebo. A significantly reduced plaque macrophage density was observed in the HDL(Milano) vs. both HDL(wild-type) and placebo groups. Plaque levels of COX-2, MCP-1, Caspase-3 antigen and MMP-2 activity were significantly reduced in the HDL(Milano) vs. both HDL(wild-type) and placebo groups. In vitro studies showed that apoA-I(Milano) protein significantly reduced expression of COX-2 and MCP-1 in oxLDL loaded macrophages vs. apoA-I(wild-type). CONCLUSIONS:Despite a similar effect on acute plaque regression, the infusion of HDL(Milano) exerts superior anti-inflammatory and plaque stabilizing effects than HDL(wild-type) in the short term.

AIMS/OBJECTIVE:The aim of this study was to investigate the effects of liver X receptors (LXRs)-β preferential activation by LXR-623 (WAY-252623), a novel LXRs agonist, on plaque progression/regression in a rabbit model of advanced atherosclerosis. METHODS AND RESULTS/RESULTS:Advanced atherosclerosis was induced in New Zealand White Rabbits (n= 41). At the end of atherosclerosis induction, animals underwent a baseline magnetic resonance imaging (MRI) and were randomized to receive LXR-623 (1.5, 5, or 15 mg/kg/day), simvastatin (5 mg/kg/day), or placebo. The combination of LXR-1.5/simvastatin was also tested. After a final MRI, animals were euthanized and their aortas processed for further analysis. Simvastatin significantly reduced lesion progression (-25%; P< 0.01) in comparison with the placebo group. A similar effect was observed in the LXR-1.5 and -5 groups. A significant regression (16.5%; P< 0.01) of existing atherosclerosis was observed in the LXR-1.5/simvastatin group. Histological and molecular analysis showed plaque stabilization in the animals treated with the LXR-1.5 and -5, and LXR-1.5/simvastatin. The effects of LXR-623 were observed in the presence of a non-significant effect on total-cholesterol, low-density lipoproteins-cholesterol, and triglyceride levels. CONCLUSION/CONCLUSIONS:The results of the present study show that LXR-623 significantly reduces the progression of atherosclerosis and induces plaque regression in combination with simvastatin. These observations could drive future development of novel anti-atherosclerotic therapeutic approaches.

BACKGROUND:The structural secuelae of acute myocardial infarction (AMI) is mostly dictated by left ventricular (LV) remodelling, leading to heart failure. Monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a critical role in LV remodelling. β-blockers are first line therapy for AMI and heart failure; however, the mechanisms responsible for their benefits remain poorly understood. Different β-blocker agents have been shown to exert beneficial activities both in AMI and heart failure, however, their role in early remodelling after ischemia/reperfusion is to be fully elucidated. We sought to compare the effect of 2 of the most prescribed β-blocker agents in early markers of LV remodelling after AMI. METHODS:A reperfused AMI was induced in Yorshire pigs, being randomized to early intravenous carvedilol, metoprolol or placebo. Twenty-four hours after reperfusion markers of early remodelling were addressed in the LV. RESULTS:The early administration of both β-blockers is able to significantly reduce macrophage infiltration as well as the expression and activity of MCP-1 and MMP-2 compared to placebo. The effects of carvedilol were much stronger than those of metoprolol. Conversely, carvedilol upregulated the expression TIMP-2 to a greater extent than metoprolol. CONCLUSIONS:In an AMI model closely mimicking human pathophysiology, the early administration of carvedilol reduced the expression of markers associated with early LV remodelling to greater extent than metoprolol. These findings may explain the superior clinical benefits exerted by carvedilol in heart failure.