Impact of patient-centred home telehealth programme on outcomes in heart failure.

BACKGROUND: Telehealth is a promising intervention to reduce readmissions and healthcare-associated costs in patients with heart failure. METHODS: We performed a retrospective analysis of the impact of telehealth on 197 heart failure patients who had successfully completed one year of home telehealth monitoring following a heart failure admission as part of a clinically mandated programme at a Veterans Affairs Medical Center. Outcomes were compared both within the group (one year before and one year after home telehealth monitoring), and to a contemporary control cohort of 870 heart failure patients who were admitted but not enrolled in home telehealth. The following outcomes were analysed: admissions for any cause, heart failure admissions, total hospital days per patient, average length of stay per admission, urgent care and emergency room visits, and primary care visits. RESULTS: Both the home telehealth and control cohorts consisted of older male patients. Total hospital days per patient was significantly reduced by home telehealth monitoring in the home telehealth group (2.4 ± 3.5) in comparison to the previous year without monitoring (4.1 ± 4.6, p < 0.0001) and to the control group (3.8 ± 5.3, p < 0.001). A significantly lower admission rate (1.1 ± 1.6) and length of stay (5.7 ± 11.3 days) were observed during home telehealth monitoring within the home telehealth group compared to the prior year (1.6 ± 1.7, p < 0.05 and 9.5 ± 14 days, p < 0.01 respectively) but not in comparison with the control group (1.4 ± 2.0, p < 0.07). The home telehealth group also had a significantly lower length of stay when compared to the control group (5.7 ± 11.3 vs 9.0 ± 14.9, p < 0.01). The number of urgent care and emergency room visits, or primary care visits, was not significantly different during home telehealth monitoring as compared to the prior year. CONCLUSIONS: Personalised and patient-centred home telehealth monitoring in heart failure patients was successful in reducing outcomes without an increase in outpatient and urgent care visits.

Systemic involvement in ACS: Using CMR imaging to compare the aortic wall in patients with and without acute coronary syndrome.

BACKGROUND/OBJECTIVES: Previous studies have demonstrated that in acute coronary syndrome (ACS), plaque destabilization and vessel inflammation, represented by vessel edema, often occur simultaneously in multiple coronaries, as well as extend to the cerebrovascular system. Our aim was to determine whether the inflammatory vascular processes occurring within the coronaries during ACS extend simultaneously to the descending aorta. METHODS: We prospectively enrolled 111 patients (56 ACS patients and 55 non-ACS patients with known coronary artery disease) to undergo cardiac magnetic resonance of the thoracic aortic wall at presentation and at three-month follow-up. The primary outcome was change in aortic wall area (AWA) and maximal aortic wall thickness (AWT) from baseline to three-month follow-up. Secondary outcomes were baseline and follow-up differences in AWA and AWT, and changes in C-reactive protein (CRP). RESULTS: There was a significant reduction in mean AWA (p = 0.01) and AWT (p = 0.01) between index and follow up scans in ACS group, with no significant changes in non ACS group (both p>0.1) and no difference between ACS and non-ACS groups (p = 0.22). There was no significant difference in AWA and AWT at baseline (p>0.36) and follow-up (p>0.2) between groups. There was a significant reduction in CRP in both groups (p<0.01), with higher reduction in ACS patients (p<0.01). CONCLUSIONS: There was a reduction in aortic wall size, aortic wall area, and aortic wall thickness in patients presenting with ACS, and no change in non-ACS patients. There were no interval between-group differences in these measurements. We observed a reduction in C-reactive protein in both groups, with higher reduction noted in ACS patients.

Reduced Right Ventricular Function Predicts Long-Term Cardiac Re-Hospitalization after Cardiac Surgery.

BACKGROUND: The significance of right ventricular ejection fraction (RVEF), independent of left ventricular ejection fraction (LVEF), following isolated coronary artery bypass grafting (CABG) and valve procedures remains unknown. The aim of this study is to examine the significance of abnormal RVEF by cardiac magnetic resonance (CMR), independent of LVEF in predicting outcomes of patients undergoing isolated CABG and valve surgery. METHODS: From 2007 to 2009, 109 consecutive patients (mean age, 66 years; 38% female) were referred for pre-operative CMR. Abnormal RVEF and LVEF were considered <35% and <45%, respectively. Elective primary procedures include CABG (56%) and valve (44%). Thirty-day outcomes were perioperative complications, length of stay, cardiac re-hospitalizations and early mortaility; long-term (> 30 days) outcomes included, cardiac re-hospitalization, worsening congestive heart failure and mortality. Mean clinical follow up was 14 months. FINDINGS: Forty-eight patients had reduced RVEF (mean 25%) and 61 patients had normal RVEF (mean 50%) (p<0.001). Fifty-four patients had reduced LVEF (mean 30%) and 55 patients had normal LVEF (mean 59%) (p<0.001). Patients with reduced RVEF had a higher incidence of long-term cardiac re-hospitalization vs. patients with normal RVEF (31% vs.13%, p<0.05). Abnormal RVEF was a predictor for long-term cardiac re-hospitalization (HR 3.01 [CI 1.5-7.9], p<0.03). Reduced LVEF did not influence long-term cardiac re-hospitalization. CONCLUSION: Abnormal RVEF is a stronger predictor for long-term cardiac re-hospitalization than abnormal LVEF in patients undergoing isolated CABG and valve procedures.

Utilization of trained volunteers decreases 30-day readmissions for heart failure.

Background: This study evaluated the effectiveness of using trained volunteer staff in reducing 30-day readmissions of congestive heart failure (CHF) patients.Methods: From June 2010 to December 2010, 137 patients (mean age 73 years) hospitalized for CHF were randomly assigned to either: an interventional arm (arm A) receiving dietary and pharmacologic education by a trained volunteer, follow-up telephone calls within 48 hours, and a month of weekly calls; ora control arm (arm B) receiving standard care. Primary outcomes were 30-day readmission rates for CHF and worsening New York Heart Association (NYHA) functional classification; composite and all-cause mortality were secondary outcomes.Results: Arm A patients had decreased 30-day readmissions (7% vs 19%; P ! .05) with a relative risk reduction (RRR) of 63% and an absolute risk reduction (ARR) of 12%. The composite outcome of 30-day readmission, worsening NYHA functional class, and death was decreased in the arm A (24% vs 49%;P ! .05; RRR 51%, ARR 25%). Standard-care treatment and hypertension, age $65 years and hypertension,and cigarette smoking were predictors of increased risk for readmissions, worsening NYHA functional class, and all-cause mortality, respectively, in the multivariable analysis.Conclusions: Utilizing trained volunteer staff to improve patient education and engagement might be an efficient and low-cost intervention to reduce CHF readmissions.

Utilization of trained volunteers decreases 30-day readmissions for heart failure.

BACKGROUND: This study evaluated the effectiveness of using trained volunteer staff in reducing 30-day readmissions of congestive heart failure (CHF) patients. METHODS: From June 2010 to December 2010, 137 patients (mean age 73 years) hospitalized for CHF were randomly assigned to either: an interventional arm (arm A) receiving dietary and pharmacologic education by a trained volunteer, follow-up telephone calls within 48 hours, and a month of weekly calls; or a control arm (arm B) receiving standard care. Primary outcomes were 30-day readmission rates for CHF and worsening New York Heart Association (NYHA) functional classification; composite and all-cause mortality were secondary outcomes. RESULTS: Arm A patients had decreased 30-day readmissions (7% vs 19%; P < .05) with a relative risk reduction (RRR) of 63% and an absolute risk reduction (ARR) of 12%. The composite outcome of 30-day readmission, worsening NYHA functional class, and death was decreased in the arm A (24% vs 49%; P < .05; RRR 51%, ARR 25%). Standard-care treatment and hypertension, age ≥65 years and hypertension, and cigarette smoking were predictors of increased risk for readmissions, worsening NYHA functional class, and all-cause mortality, respectively, in the multivariable analysis. CONCLUSIONS: Utilizing trained volunteer staff to improve patient education and engagement might be an efficient and low-cost intervention to reduce CHF readmissions.

Evolving indications for tricuspid valve surgery.

OPINION STATEMENT: More attention has been paid to the mitral valve (MV) than the tricuspid valve (TV), and this relative paucity of data has led to confusion regarding the timing of TV surgery. We review the American College of Cardiology/American Heart Association and European Society of Cardiology guidelines to identify areas of concordance (severe tricuspid regurgitation [TR] in a patient undergoing mitral valve surgery); discordance (less than severe TR but with markers for late TR recurrence such as pulmonary hypertension, a dilated TV annulus, atrial fibrillation, permanent transtricuspid pacing wires and others); and disagreement (surgery for primary TR). We provide our perspective from Northwestern University on these issues and where the guidelines are silent (TR in patients undergoing non-mitral valve operations). Finally, we review recent publications on the results of TV repair and replacement. Although there have been scant publications in the past, there have been more useful publications in recent years to guide our decision making.

Durability of functional tricuspid valve repair.

Current tricuspid repair techniques have variable and disappointing durability. The authors of several studies have shown the superiority of ring (rather than suture or pericardial) annuloplasties; however, others suggest equal or superior results with suture or pericardial repair techniques. Indeed, recurrent significant tricuspid regurgitation has been reported consistently after repair; it is therefore unclear which technique provides the best long-term outcomes and in which patients. In this study, we evaluated the outcomes of different tricuspid repairs regarding durability and analyzed the risk factors for repair failure. We also presented our current approach to surgical management of functional tricuspid regurgitation on the basis of recent studies and our experience treating patients with heart failure.

Understanding the C-pulse device and its potential to treat heart failure.

The Sunshine Heart C-Pulse (C-Pulse; Sunshine Heart Inc., Tustin, CA) device is an extra-aortic implantable counterpulsation pump designed as a non-blood contacting ambulatory heart assist device, which may provide relief from symptoms for class II-III congestive heart failure patients. It has a comparable hemodynamic augmentation to intra-aortic balloon counterpulsation devices. The C-Pulse cuff is implanted through a median sternotomy, secured around the ascending aorta, and pneumatically driven by an external system controller. Pre-clinical studies in the acute pig model, and initial temporary clinical studies in patients undergoing off-pump coronary bypass surgery have shown substantial increase in diastolic perfusion of the coronary vessels, which translated to a favorable improvement in ventricular function. A U.S. prospective multi-center trial to evaluate the safety and efficacy of the C-Pulse in class III patients with moderate heart failure is now in progress.

Minimally invasive surgery for atrial fibrillation.

There are currently many promising innovations using minimal-access procedures, instrumentation, and devices for stand-alone and concomitant AF. It is prudent to say that within a few years, surgeons will be performing a number of surgical ablations with minimal complexity and maximum effectiveness, using port-accessed, video-assisted, and robot-assisted surgical techniques with the aid of hybrid approaches, less invasive devices, and specialized navigation instruments.

Endothelial progenitor cells as a sole source for ex vivo seeding of tissue-engineered heart valves.

PURPOSES: We investigated whether circulating endothelial progenitor cells (EPCs) can be used as a cell source for the creation of a tissue-engineered heart valve (TEHV). METHODS: Trileaflet valved conduits were fabricated using nonwoven polyglycolic acid/poly-4-hydroxybutyrate polymer. Ovine peripheral blood EPCs were dynamically seeded onto a valved conduit and incubated for 7, 14, and 21 days. RESULTS: Before seeding, EPCs were shown to express CD31(+), eNOS(+), and VE-Cadherin(+) but not alpha-smooth muscle actin. Histological analysis demonstrated relatively homogenous cellular ingrowth throughout the valved conduit. TEHV constructs revealed the presence of endothelial cell (EC) markers and alpha-smooth muscle actin(+) cells comparable with native valves. Protein levels were comparable with native valves and exceeded those in unseeded controls. EPC-TEHV demonstrated a temporal pattern of matrix metalloproteinases-2/9 expression and tissue inhibitors of metalloproteinase activities comparable to that of native valves. Mechanical properties of EPC-TEHV demonstrated significantly greater stiffness than that of the unseeded scaffolds and native valves. CONCLUSIONS: Circulating EPC appears to have the potential to provide both interstitial and endothelial functions and could potentially serve as a single-cell source for construction of autologous heart valves.

The role of organ level conditioning on the promotion of engineered heart valve tissue development in-vitro using mesenchymal stem cells.

We have previously shown that combined flexure and flow (CFF) augment engineered heart valve tissue formation using bone marrow-derived mesenchymal stem cells (MSC) seeded on polyglycolic acid (PGA)/poly-L-lactic acid (PLLA) blend nonwoven fibrous scaffolds (Engelmayr, et al., Biomaterials 2006; vol. 27 pp. 6083-95). In the present study, we sought to determine if these phenomena were reproducible at the organ level in a functional tri-leaflet valve. Tissue engineered valve constructs (TEVC) were fabricated using PGA/PLLA nonwoven fibrous scaffolds then seeded with MSCs. Tissue formation rates using both standard and augmented (using basic fibroblast growth factor [bFGF] and ascorbic acid-2-phosphate [AA2P]) media to enhance the overall production of collagen were evaluated, along with their relation to the local fluid flow fields. The resulting TEVCs were statically cultured for 3 weeks, followed by a 3 week dynamic culture period using our organ level bioreactor (Hildebrand et al., ABME, Vol. 32, pp. 1039-49, 2004) under approximated pulmonary artery conditions. Results indicated that supplemented media accelerated collagen formation (approximately 185% increase in collagen mass/MSC compared to standard media), as well as increasing collagen mass production from 3.90 to 4.43 pg/cell/week from 3 to 6 weeks. Using augmented media, dynamic conditioning increased collagen mass production rate from 7.23 to 13.65 pg/cell/week (88.8%) during the dynamic culture period, along with greater preservation of net DNA. Moreover, when compared to our previous CFF study, organ level conditioning increased the collagen production rate from 4.76 to 6.42 pg/cell/week (35%). Newly conducted CFD studies of the CFF specimen flow patterns suggested that oscillatory surface shear stresses were surprisingly similar to a tri-leaflet valve. Overall, we found that the use of simulated pulmonary artery conditions resulted in substantially larger collagen mass production levels and rates found in our earlier CFF study. Moreover, given the fact that the scaffolds underwent modest strains (approximately 7% max) during either CFF or physiological conditioning, the oscillatory surface shear stresses estimated in both studies may play a substantial role in eliciting MSC collagen production in the highly dynamic engineered heart valve fluid mechanical environment.

Development of microfluidics as endothelial progenitor cell capture technology for cardiovascular tissue engineering and diagnostic medicine.

We have developed a unique microfluidic platform capable of capturing circulating endothelial progenitor cells (EPCs) by understanding surface chemistries and adhesion profiles. The surface of a variable-shear-stress microfluidic device was conjugated with 6 different antibodies [anti-CD34, -CD31, -vascular endothelial growth factor receptor-2 (VEGFR-2), -CD146, -CD45, and -von Willebrand factor (vWF)] designed to match the surface antigens on ovine peripheral blood-derived EPCs. Microfluidic analysis showed a shear-stress-dependent decrease in EPC adhesion on attached surface antigens. EPCs exhibited increased adhesion to antibodies against CD34, VEGFR-2, CD31, and CD146 compared to CD45, consistent with their endothelial cell-specific surface profile, when exposed to a minimum shear stress of 1.47 dyn/cm(2). Bone-marrow-derived mesenchymal stem cells and artery-derived endothelial and smooth muscle cells were used to demonstrate the specificity of the EPC microfluidic device. Coated hematopoietic specific-surface (CD45) and granular vWF antibodies, as well as uncoated bare glass and substrate (1% BSA), were utilized as controls. Microfluidic devices have been developed as an EPC capture platform using immobilized antibodies targeted as EPC surface antigens. This EPC chip may provide a new and effective tool for addressing challenges in cardiovascular disease and tissue engineering.

Stem cell-derived, tissue-engineered pulmonary artery augmentation patches in vivo.

BACKGROUND: Reconstruction of the right ventricular outflow tract is a frequently encountered component of many congenital cardiac repairs. We sought to tissue engineer pulmonary artery augmentation patches from retrovirally labeled endothelial progenitor and mesenchymal stem cells and determine the persistence of the seeded cells in vivo. METHODS: Autologous ovine endothelial progenitor and mesenchymal stem cells were labeled with a retroviral vector encoding green and red fluorescent proteins, coseeded onto biopolymers, and cultured for 5 days. The tissue-engineered patches were implanted into the main pulmonary artery with 1, 2, 4, and 6 week in vivo maturation (n = 8). In vivo evaluation included ultrasonography and angiography, with preimplant and explanted specimens evaluated using histologic examination and immunofluorescence. RESULTS: Echocardiography at each time demonstrated laminar pulmonary artery flow without a pressure gradient across the replaced segment. Pulmonary angiography did not exhibit stenosis or aneurysmal change. Gross appearance of all explanted patches showed progressive tissue formation with increased length of time in vivo. Retrovirally labeled cellular persistence was 96%, 82%, 85%, and 66% at 1, 2, 4, and 6 weeks after implantation, respectively. Early in the in vivo remodeling period, the number of green fluorescent protein-positive endothelial progenitor cells was 1.6 fold greater than the red fluorescent protein-positive mesenchymal stem cells. As in vivo remodeling continued, red fluorescent protein-expressing mesenchymal stem cells were expressed 1.2 to 1.7 times that of the green fluorescent protein-positive endothelial progenitor cells. CONCLUSIONS: The data demonstrate the successful creation of an anatomically functional, autologous tissue-engineered pulmonary artery using coseeded progenitor cell sources. Labeled implanted stem cells persisted in the engineered construct, suggesting that in vitro seeding is necessary to engineer tissue. This study demonstrates an effective method to track multiple cell types after implantation.

Protein precoating of elastomeric tissue-engineering scaffolds increased cellularity, enhanced extracellular matrix protein production, and differentially regulated the phenotypes of circulating endothelial progenitor cells.

BACKGROUND: Optimal cell sources and scaffold-cell interactions remain unanswered questions for tissue engineering of heart valves. We assessed the effect of different protein precoatings on a single scaffold type (elastomeric poly (glycerol sebacate)) with a single cell source (endothelial progenitor cells). METHODS AND RESULTS: Elastomeric poly (glycerol sebacate) scaffolds were precoated with laminin, fibronectin, fibrin, collagen types I/III, or elastin. Characterized ovine peripheral blood endothelial progenitor cells were seeded onto scaffolds for 3 days followed by 14 days incubation. Endothelial progenitor cells were CD31+, vWF+, and alpha-SMA- before seeding confirmed by immunohistochemistry and immunoblotting. Both precoated and uncoated scaffolds demonstrated surface expression of CD31+ and vWF+, alpha-SMA+ cells and were found in the "interstitium" of the scaffold. Protein precoating of elastomeric poly (glycerol sebacate) scaffolds revealed significantly increased cellularity and altered the phenotypes of endothelial progenitor cells, which resulted in changes in cellular behavior and extracellular matrix production. Moreover, mechanical flexure testing demonstrated decreased effective stiffness of the seeded scaffolds compared with unseeded controls. CONCLUSIONS: Scaffold precoating with extracellular matrix proteins can allow more precise "engineering" of cellular behavior in the development of tissue engineering of heart valves constructs by altering extracellular matrix production and cell phenotype.

Endothelial progenitor and mesenchymal stem cell-derived cells persist in tissue-engineered patch in vivo: application of green and red fluorescent protein-expressing retroviral vector.

An unresolved question regarding tissue-engineered (TE) cardiac valves and vessels is the fate of the transplanted cells in vivo. We have developed a strategy to track the anatomic location of seeded cells within TE constructs and neighboring tissues using a retroviral vector system encoding green and red fluorescent proteins (GFPs and RFPs, respectively) in ovine circulating endothelial progenitor cells (EPCs) and bone marrow-derived mesenchymal stem cells (BMSCs). We demonstrate that stable transduction ex vivo with high-titer Moloney murine leukemia virus-based retroviral vector yields transduction efficiency of greater than 97% GFP(+) EPC- and RFP(+) mesenchymal stem cell (MSC)-derived cells. Cellular phenotype and transgene expression were also maintained through 25 subsequent passages. Using a retroviral vector system to distinguish our pre-seeded cells from tissue-resident progenitor cells and circulating endothelial and marrow-derived precursors, we simultaneously co-seeded 2 x 10(6) GFP(+) EPCs and 2 x 10(5) RFP(+) MSCs onto the TE patches. In a series of ovine pulmonary artery patch augmentation studies, transplanted GFP(+) EPC- and RFP(+) MSC-derived cells persisted within the TE patch 7 to 14 days after implantation, as identified using immunofluorescence. Analysis showed 81% luminal coverage of the TE patches before implantation with transduced cells, increasing to 96% at day 7 and decreasing to 67% at day 14 post-implantation. This suggests a temporal association between retroviral expression of progenitor cells and mediating effects of these cells on the physiological remodeling and maturation of the TE constructs. To our knowledge, this is the first cardiovascular tissue-engineering in vivo study using a double-labeling method to demonstrate a direct evidence of the source, persistence, and incorporation into a TE vascular patch of co-cultured and simultaneously pre-seeded adult progenitor cells.

Cyclic flexure and laminar flow synergistically accelerate mesenchymal stem cell-mediated engineered tissue formation: Implications for engineered heart valve tissues.

Bone marrow-derived mesenchymal stem cells (BMSCs) are relatively accessible and exhibit a pluripotency suitable for cardiovascular applications such as tissue-engineered heart valves (TEHVs). Recently, Sutherland et al. [From stem cells to viable autologous semilunar heart valve. Circulation 2005; 111(21): 2783-91] demonstrated that BMSC-seeded TEHV can successfully function as pulmonary valve substitutes in juvenile sheep for at least 8 months. Toward determining appropriate mechanical stimuli for use in BMSC-seeded TEHV cultivation, we investigated the independent and coupled effects of two mechanical stimuli physiologically relevant to heart valves-cyclic flexure and laminar flow (i.e. fluid shear stress)-on BMSC-mediated tissue formation. BMSC isolated from juvenile sheep were expanded and seeded onto rectangular strips of nonwoven 50:50 blend poly(glycolic acid) (PGA) and poly(l-lactic acid) (PLLA) scaffolds. Following 4 days static culture, BMSC-seeded scaffolds were loaded into a novel flex-stretch-flow (FSF) bioreactor and incubated under static (n=12), cyclic flexure (n=12), laminar flow (avg. wall shear stress=1.1505 dyne/cm(2); n=12) and combined flex-flow (n=12) conditions for 1 (n=6) and 3 (n=6) weeks. By 3 weeks, the flex-flow group exhibited dramatically accelerated tissue formation compared with all other groups, including a 75% higher collagen content of 844+/-278 microg/g wet weight (p<0.05), and an effective stiffness (E) value of 948+/-233 kPa. Importantly, collagen and E values were not significantly different from values measured for vascular smooth muscle cell (SMC) -seeded scaffolds incubated under conditions of flexure alone [Engelmayr et al. The independent role of cyclic flexure in the early in vitro development of an engineered heart valve tissue. Biomaterials 2005; 26(2): 175-87], suggesting that BMSC-seeded TEHV can be optimized to yield results comparable to SMC-seeded TEHV. We thus demonstrated that cyclic flexure and laminar flow can synergistically accelerate BMSC-mediated tissue formation, providing a basis for the rational design of in vitro conditioning regimens for BMSC-seeded TEHV.

Transforming growth factor-beta1 modulates extracellular matrix production, proliferation, and apoptosis of endothelial progenitor cells in tissue-engineering scaffolds.

BACKGROUND: Valvular endothelial cells and circulating endothelial progenitor cells (EPCs) can undergo apparent phenotypic change from endothelial to mesenchymal cell type. Here we investigated whether EPCs can promote extracellular matrix formation in tissue engineering scaffolds in response to transforming growth factor (TGF)-beta1. Method and Results- Characterized ovine peripheral blood EPCs were seeded onto poly (glycolic acid)/poly (4-hydroxybutyrate) scaffolds for 5 days. After seeding at 2 x 10(6) cells/cm2, scaffolds were incubated for 5 days in a roller bottle, with or without the addition of TGF-beta1. After seeding at 15 x 10(6) cells/cm2, scaffolds were incubated for 10 days in a roller bottle with or without the addition of TGF-beta1 for the first 5 days. Using immunofluorescence and Western blotting, we demonstrated that EPCs initially exhibit an endothelial phenotype (ie, CD31+, von Willebrand factor+, and alpha-smooth muscle actin (SMA)-) and can undergo a phenotypic change toward mesenchymal transformation (ie, CD31+ and alpha-SMA+) in response to TGF-beta1. Scanning electron microscopy and histology revealed enhanced tissue formation in EPC-TGF-beta1 scaffolds. In both the 10- and 15-day experiments, EPC-TGF-beta1 scaffolds exhibited a trend of increased DNA content compared with unstimulated EPC scaffolds. TGF-beta1-mediated endothelial to mesenchymal transformation correlated with enhanced expression of laminin and fibronectin within scaffolds evidenced by Western blotting. Strong expression of tropoelastin was observed in response to TGF-beta1 equal to that in the unstimulated EPC. In the 15-day experiments, TGF-beta1-stimulated scaffolds revealed dramatically enhanced collagen production (types I and III) and incorporated more 5-bromodeoxyuridine and TUNEL staining compared with unstimulated controls. CONCLUSIONS: Stimulation of EPC-seeded tissue engineering scaffolds with TGF-beta1 in vitro resulted in a more organized cellular architecture with glycoprotein, collagen, and elastin synthesis, and thus noninvasively isolated EPCs coupled with the pleiotropic actions of TGF-beta1 could offer new strategies to guide tissue formation in engineered cardiac valves.

Angiotensin type 2 receptor is expressed in murine atherosclerotic lesions and modulates lesion evolution.

BACKGROUND: In the vasculature, the angiotensin type 2 (AT2) receptor (AT2R) exerts antiproliferative, antifibrotic, and proapoptotic effects. Normal adult animals have low AT2R expression; however, vascular injury and exposure to proinflammatory cytokines augment AT2R levels. We hypothesized that AT2R expression increases during initiation and progression of atherosclerosis. METHODS AND RESULTS: Atherosclerotic lesions of apolipoprotein (Apo) E(-/-) mice contained AT2Rs, measured by real-time polymerase chain reaction and confirmed by immunohistochemistry. To test the consequences of this expression, male ApoE(-/-), angiotensin II type 2 receptor-deficient (Agtr2-), and ApoE(-/-), wild-type (Agtr2+) mice consumed a high-cholesterol diet from 4 weeks of age. Ten weeks later, overall area and cellular composition of aortic arch lesions did not differ significantly among genotypes. After 16 weeks, ApoE(-/-)/Agtr2+, but not ApoE(-/-)/Agtr2- mice had dramatic decreases in percent positive area of macrophages, smooth muscles, lipids, and collagen. Diminished bromodeoxyuridine incorporation and increased TUNEL staining accompanied these decreases. CONCLUSIONS: Thus, loss of AT2R during the evolution of atherosclerotic lesions augmented the extent of cellularity of atherosclerotic lesions, establishing AT2R as a modulator of atherogenesis.