RESULTS: There were 48 males (82.8%) with a median age at surgery of 11.3 years (0.04 -17.9).Indications for surgery were stenosis in 32 (55.2%), regurgitation in 13 (22.4%)and mixed aortic valve disease in 13 (22.4%)patients.Survival at 10 and 25 years was 96.2% and 93.9%, respectively.There was one (1.7%)hospital death and two (3.4%) late deaths.Freedom from pulmonary autograftrelated reintervention (the aortic root prosthesis) was 93.9% and 69.7% at 10 and 25 years, respectively.Eleven patients underwent reoperations on the autograft at a median followup of 16.1 years.Aortic valve-sparing surgery was performed in 6 patients and a Bentall procedure in 4 patients (3 mechanical, 1 homograft).Over the study period, twice as many patients (34.5%) required pulmonary homograftrelated (right ventricular outflow tract) reintervention (10 transcatheter, 10 surgical conduit replacement).Freedom from homograft-related reintervention was 73% and 50.4% at 10 and 25 years, respectively.CONCLUSION: The Ross procedure is associated with excellent long term survival.Late reintervention for the homograft was more common than for the pulmonary autograft in our cohort.

Following a myocardial infarction (MI), cells such as mast cells, bone marrow stem cells, and fibroblasts play a role in tissue regeneration and wound healing. Cardiac-resident fibroblasts phenotypically convert to myofibroblasts, which have characteristics of smooth muscle cells and exert contractile force to help prevent infarct expansion and ventricular dilatation. Myofibroblasts can also be driven from other sources, including bone marrow-derived mesenchymal stem cells (MSCs). Previous work in our lab showed that mast cell deficient (c-kit deficient) mice undergo rapid ventricular dilatation compared with wild-type mice and accumulate fewer myofibroblasts in the infarct region post-MI. Therefore, mast cells may play an important role in myofibroblast accumulation in response to cardiac injury. We investigated the role of mast cells and miR-145 and miR-143 in the proliferation and differentiation of MSCs to myofibroblasts since miR-145 and miR-143 have been shown to be involved in the regulation of smooth muscle phenotype.

The delivery of growth factors to the heart following a myocardial infarction can enhance angiogenesis and tissue repair. Intrapericardial administration of growth factors can induce a therapeutic response in the pathological heart; however, a single injection is prone to degradation and generates a global effect. Biomaterial-based delivery systems constructed for epicardial implantation can be designed to localize and prolong growth factor release to elicit a robust regenerative response. Using a water-in-oil single emulsion, we produced non-porous Ca2+-alginate microspheres with an average diameter of ∼2 μm. To construct an implantable cytokine delivery system with prolonged protein release, the microspheres were compacted via centrifugation into a biodegradable porous patch. To evaluate protein release, fluorescein-conjugated bovine serum albumin was loaded into the patch, which was subsequently incubated in PBS. The fluorescent signal of the protein released into the surrounding PBS was measured daily for 11 days. The bulk release of protein occurred over 5 days and closely resembled first-order kinetics. At 1, 3, and 5 days, protein released was 30%, 70%, and 85%, respectively, avoiding an early burst release. To evaluate the biological function of cytokine release from the patch, patches were loaded with vascular endothelial growth factor (VEGF) and incubated in cell growth media. The release media was collected over 3 days and incubated with human umbilical vein endothelial cells. An MTT assay showed a 40% increase (p<0.01) in proliferation compared to cells treated with release media from a patch without VEGF. To determine its effectiveness as a suitable biomaterial release system in vivo, the patch was loaded with VEGF and implanted onto the epicardium of a rat heart following coronary artery ligation and secured in place using a chitosan sheet. Patch degradation was monitored with magnetic resonance imaging. The patch was still present at the site of implantation after 1 month, but only 50% of the patch remained. Histology revealed cell infiltration into the patch, indicating a continuous connection between the patch and underlying heart to facilitate protein diffusion. The epicardial implantation of a VEGF-loaded patch permits growth factor delivery into a cardiac region and provides an opportunity to induce localized angiogenesis. Sustained release of VEGF or other growth factors with biomaterial-based delivery systems, such as this epicardial patch, could be a powerful therapeutic strategy. This new tissue-engineered platform provides an opportunity to improve recovery and tissue regeneration of the ischemic heart.

Cell transplantation after a myocardial infarction improves the recovery of ventricular function, but does not replace the lost cardiomyocytes (CMs). The application of a CM seeded biodegradable patch to the infarct may restore function if the cells form an integrated cardiac tissue. We developed a novel cyclical-stretching cardiac patch culture system for the production of three-dimensional tissues in vitro. This system supports the maturation of human embryonic stem cell-derived CMs (hESCs). In vitro: Single hESCs were seeded into Gelfoam patches and stretched for 72 h (1.25 Hz; 37% duty cycle). Scanning electron microscopy demonstrated the CMs in the stretched patches were more elongated (control 23.8 ± 5.0 μm vs. stretch 65.7 ± 3.7 μm; P < 0.001) and clustered together into bundle-like fibers. The stretched patches were screened for cardiac ion channel genes (by real-time PCR) and the following were significantly upregulated: KCNH2 4.46×; CACNAC1 3.95×; SCN5A 3.24×; HCN4 2.37×; KCNJ2 3.61× (n = 8-10 samples/group;P < 0.01 for all genes). These channel genes could explain the greater spontaneous calcium-cycling frequency we previously demonstrated. Stretch-induced hESCs maturation and tissue formation may have been mediated through integrin-related signalling because we found that the integrin α5 subunit (ITGA5) was significantly upregulated in the stretched patches (4.93× expression; n = 8 samples/group;P < 0.01). In vivo: Nude rats had patches surgically applied to the epicardial surface 1 week after an infarct. Histological analysis two weeks later demonstrated intact patches composed of healthy hESCs in both groups. However, the stretched patches were thicker (P < 0.05, up to 20 cell layers thick) with more extensive vasculogenesis suggesting greater CM tissue formation. Cyclical stretch in vitro enhanced hESC maturation resulting in more mature tissue formation in vivo. Stretching appears to stimulate integrin signaling improving matrix formation both in vitro and in vivo. Future studies will be required to determine if the new cardiac tissue will integrate with the infracted myocardium and improve function. This novel cell culture system with rhythmic mechanical stretching may be essential for the clinical application of hESCs.

Pre-menopausal women have fewer cardiovascular complications than age-matched men. The mechanisms responsible for this protection have not been conclusively identified. We evaluated the hypothesis that uterine stem cells may home to the injured myocardium and improve outcomes. (1) Hysterectomy (Hx) was performed in young female rats (leaving the ovaries intact), and 7 days later the left coronary artery was occluded to produce a myocardial infarction (MI). Young female and male rats also underwent coronary occlusion as controls. Cardiac function in all groups at 28 days after MI was measured using echocardiography. Fractional shortening was best in non-Hx females and lower in both Hx females and males (n = 10/group, P < 0.05). (2) To investigate the homing of uterine stem cells to infarcted myocardium, uteri were removed from GFP rats and heterotopically transplanted into the abdomen of non-GFP recipients (n = 12). Seven days later, the uterine transplant recipients underwent coronary occlusion. GFP+ uterine cells were found in the recipient hearts 7 days after MI (n = 6) and persisted for 6 months (n = 6). Confocal analysis showed that most homed uterine stem cells were located around blood vessels, suggesting their involvement in neovascularization by paracrine mechanisms. (3) Since the uterine stem cells can home to infarcted myocardium, we evaluated uterine cell transplantation for cardiac regeneration. GFP+ uterine cells were injected intravenously immediately after inducing an MI in female mice 7 days post-Hx. At 28 days after cell transplantation, GFP+ cells were found to home to the injured myocardium, stimulate angiogenesis, and improve function and survival (n = 6/group, P < 0.01) in comparison to Hx mice without cell implantation. Uterine stem cells can home to the injured myocardium, enhance tissue repair, and prevent cardiac dysfunction. Uterine stem cells may play a role in the prevention of cardiovascular complications in young females.

The adult heart retains a small population of progenitor cells, which are essential for cardiac regeneration after injury. In aged individuals these cells are diminished and dysfunctional, which may contribute to progressive heart failure. The derivation of these cardiac progenitors is debated, and the methods to restore their number and function are required. Study#1: Old female mice (22 months) were lethally irradiated, and 5×106 fresh bone marrow (BM) cells from young (2 months) or old male GFP mice were infused through the tail vein to produce chimeric mice: Ym-Or (n = 60 mice total) or Om-Or (n = 60 mice total), respectively. Study #2: Following an 8-week recovery from primary marrow reconstitution, chimeric mice were again subjected to lethal irradiation followed by infusion of BM cells from old female donors. However, in some mice, the heart was protected from irradiation using a lead shield carefully positioned on the chest to create cardiac microchimeric groups as follows: Old marrow retaining Young cardiac-marrow cells in an Old recipient (Om-Yc-Or, n = 24 mice total) and Old marrow retaining Old cardiac-marrow cells in an Old recipient (Om-Oc-Or, n = 25 mice total). Real-time PCR determined the number of Y chromosomes in the female recipient hearts. Donor-derived progenitor cells in the heart were also quantified with flow cytometry and a colony-forming unit assay. Cardiac function was measured with echocardiography. Aged mice had fewer progenitors in both BM (P < 0.01) and myocardium (P < 0.05). The diminished number correlated with the extent of ventricular dysfunction after injury (P < 0.05). In aged mice, both the number of myocardial progenitors (P < 0.05) and cardiac function (P < 0.05) were restored when the BM was reconstituted with young, but not aged, BM cells. When cardiac microchimerism was established, ventricular function was restored when the cardiac nascent progenitor cells were derived from young BM cells prior to injury. The cardiac-resident progenitors in the aged myocardium actively proliferated (P < 0.01) after myocardial injury and enhanced cardiac repair through the paracrine mechanisms. In aged individuals, BM reconstitution with young BM cells restored progenitors in both the BM and the heart. The aged heart was rejuvenated with young BM cells.

Cardiovascular disease is the number-one cause of mortality in the developed world. The aim of this study is to define the mechanisms by which bone marrow progenitor cells are mobilized in response to cardiac ischemic injury. We used a closed-chest model of murine cardiac infarction/reperfusion, which segregated the surgical thoracotomy from the induction of cardiac infarction, so that we could study isolated fluctuations in cytokines without the confounding impact of surgery. We show here that bone marrow activation of the c-kit tyrosine kinase receptor in response to released soluble KitL is necessary for bone marrow progenitor cell mobilization after ischemic cardiac injury. We also show that release of KitL and c-kit activation require the activity of matrix metalloproteinase-9 within the bone marrow compartment. Finally, we demonstrate that mice with c-kit dysfunction develop cardiac failure after myocardial infarction and that bone marrow transplantation rescues the failing cardiac phenotype. In light of the ongoing trials of progenitor cell therapy for heart disease, our study outlines the endogenous repair mechanisms that are invoked after cardiac injury. Amplification of this pathway may aid in restoration of cardiac function after myocardial infarction.

Cardioprotective strategies are needed to prevent perioperative myocardial dysfunction in high-risk patients undergoing cardiac surgery. Despite accumulating evidence that statins exert lipid-independent cardioprotective effects, these have been ascribed primarily to improvements in endothelial function and neutrophil-endothelial interaction. The direct effects of statins on cardiomyocytes (independent of endothelial cells) remain unknown. Using a well-characterized model of low-volume hypoxia and reoxygenation, we studied the effects of pravastatin on human ventricular cardiomyocytes. Cardiomyocytes were subjected to 90 min of low-volume hypoxia and 30 min of reoxygenation in the presence and absence of pravastatin (1, 10, and 100 μm) (n = 10 per group). In some experiments, the effects of endothelin (ET) receptor blockade (with bosentan) and nitric oxide synthase (NOS) inhibition (with l-NAME) on pravastatin-mediated cardioprotection were evaluated. Cell survival, NO, and ET-1 production and protein kinase Akt activation were determined. Pravastatin treatment prevented cardiomyocyte cell death following simulated hypoxia and reoxygenation (P < 0.01). This effect was mediated via an increase in NO release, decrease in myocyte ET-1 production/action, and an increase in protein kinase Akt activation. We demonstrate, for the first time, novel protective effects of pravastatin in human ventricular cardiomyocytes independent of endothelial cells or other cell types. Statin therapy may restore ischemic hearts to full functional integrity during cardioplegic arrest through a direct effect on cardiomyocyte survival.

HomeCirculationVol. 107, No. 16Bicuspid Aortic Valve and Coronary Anomalies Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBBicuspid Aortic Valve and Coronary Anomalies Roberto Barriales-Villa, MD, FESC and Manuel Penas-Lado, MD César Morís, MD, FESC Roberto Barriales-VillaRoberto Barriales-Villa Cardiology Service, Complexo Hospitalario de Pontevedra, Pontevedra, Spain, Search for more papers by this author and Manuel Penas-LadoManuel Penas-Lado Cardiology Service, Complexo Hospitalario de Pontevedra, Pontevedra, Spain, Search for more papers by this author César MorísCésar Morís Cardiology Service, Hospital Central de Asturias, Oviedo, Spain Search for more papers by this author Originally published29 Apr 2003https://doi.org/10.1161/01.CIR.0000067687.37985.C4Circulation. 2003;107:e105To the Editor:We congratulate Dr Fedak et al1 on their excellent review of bicuspid aortic valve. As the authors mention, a clear relation, possibly genetic, seems to exist between a bicuspid aortic valve and coronary artery anomalies.1 Anomalous origins of the right2 and left3 coronary arteries have been noted in patients with bicuspid aortic valves. Because many of these patients will require aortic valve replacement, we believe that coronary angiography (or another imaging technique, such as magnetic angioresonance4 or an electron beam computed tomography5) is essential in these patients before surgery, independent of their age and clinical suspicion of associated coronary atherosclerotic disease. The identification of a coronary anomaly would avoid possible injury to the anomalous artery during surgical repair. References 1 Fedak PWM, Verma S, David TE, et al. Clinical and pathophysiological implications of a bicuspid aortic valve. Circulation. 2002; 106: 900–904.LinkGoogle Scholar2 Palomo AR, Schrager BR, Chahine RA. Anomalous origin of the right coronary artery from the ascending aorta high above the left posterior sinus of Valsalva of a bicuspid aortic valve. Am Heart J. 1985; 109: 902–904.CrossrefMedlineGoogle Scholar3 Doty DB. Anomalous origin of the left circumflex coronary artery associated with bicuspid aortic valve. J Thorac Cardiovasc Surg. 2001; 122: 842–843.CrossrefMedlineGoogle Scholar4 McConnell MV, Ganz P, Selwyn AP, et al. Identification of anomalous coronary arteries and their anatomic course by magnetic resonance coronary angiography. Circulation. 1995; 92: 3158–3162.CrossrefMedlineGoogle Scholar5 Rensing BJ, Bongaerts A, van Geuns RJ, et al. Intravenous coronary angiography by electron beam computed tomography: a clinical evaluation. Circulation. 1998; 98: 2509–2512.CrossrefMedlineGoogle ScholarcirculationahaCirculationCirculationCirculation0009-73221524-4539Lippincott Williams & WilkinsResponseFedak Paul W.M., , MD, Verma Subodh, , MD, PhD, David Tirone E., , MD, Weisel Richard D., , MD, Leask Richard L., , PhD, and Butany Jagdish, , MD29042003Coronary anomalies are rare congenital cardiac malformations that occur in less than 1% of the population. When present, these malformations are usually an ectopic origin of the right or left coronary artery from the aorta. In rare circumstances, coronary anomalies can result in myocardial malperfusion with devastating clinical consequences. However, the vast majority of coronary anomalies are benign, and accordingly, they are often identified only as incidental findings during diagnostic testing for other reasons. When coronary anomalies are suspected, they can be identified by a number of different imaging modalities, as indicated by Barriales-Villa and colleagues. Although coronary angiography remains the gold standard, a noninvasive approach with coronary magnetic resonance angiography may replace conventional methods in the future.1Patients with bicuspid aortic valve disease may have a coexisting coronary anomaly. When undergoing valve repair or replacement, there is a potential risk of coronary injury during surgery. The preoperative determination of the presence and location of an anomalous coronary artery, in theory, may reduce the risk of injury at the time of surgery. However, in contrast to Barriales-Villa and colleagues, we do not believe that the routine use of coronary angiography is indicated in all patients with bicuspid aortic valve disease before surgery. Echocardiography is a readily available, practical, and noninvasive imaging modality that is performed in all patients with valve disease before surgery. Echocardiography is capable of detecting coronary anomalies if suspected at the time of study, and in fact, is sometimes capable of detecting anomalies missed by conventional angiography.2,3Preoperative tests, even if indicated, can give incorrect results. There is no substitute for a careful and comprehensive inspection of the aorta at the time of surgery to avoid injury to an anomalous coronary artery. Echocardiography is routinely performed in these patients before surgery, and additional tests to search for coronary anomalies may not be necessary. Despite a few infrequent reports in the literature of injury to an anomalous coronary artery during valve replacement, in our surgical series of bicuspid valve patients,4 we did not make any extra efforts to identify coronary anomalies before surgery, and we have successfully avoided this complication. In patients with bicuspid aortic valve disease, we believe that preoperative testing should be considered on a case-by-case basis in coordination with the surgeon performing the procedure. Previous Back to top Next FiguresReferencesRelatedDetailsCited By Cho S, Jeon K and Bae K (2015) Anomalous origin and aneurysm of the right coronary artery associated with congenital bicuspid aortic valve: MDCT findings, SpringerPlus, 10.1186/s40064-015-1214-1, 4:1, Online publication date: 1-Dec-2015. Srichai M and Mason D (2014) Coronary Artery Anomalies Cardiac CT and MR for Adult Congenital Heart Disease, 10.1007/978-1-4614-8875-0_27, (603-634), . Lowry A, Olabiyi O, Adachi I, Moodie D and Knudson J (2013) Coronary Artery Anatomy in Congenital Heart Disease, Congenital Heart Disease, 10.1111/chd.12067, 8:3, (187-202), Online publication date: 1-May-2013. Unzué-Vallejo L, Andreu-Dussac J, Sánchez-Sánchez V and Gragera-Torres F (2012) Anomalía coronaria congénita familiar, Revista Española de Cardiología, 10.1016/j.recesp.2012.01.023, 65:9, (859-861), Online publication date: 1-Sep-2012. Unzué-Vallejo L, Andreu-Dussac J, Sánchez-Sánchez V and Gragera-Torres F (2012) Congenital Hereditary Anomalous Coronary Artery Origin, Revista Española de Cardiología (English Edition), 10.1016/j.rec.2012.01.025, 65:9, (859-861), Online publication date: 1-Sep-2012. Barriales-Villa R, Morís C, Sanmartín J, Fernández E, Pajín F and Ruiz Nodar J (2006) Anomalous Coronary Arteries Originating in the Contralateral Sinus of Valsalva: Registry of Thirteen Spanish Hospitals (RACES), Revista Española de Cardiología (English Edition), 10.1016/S1885-5857(07)60013-9, 59:6, (620-623), Online publication date: 1-Jun-2006. Barriales-Villa R and Morís de la Tassa C (2006) Congenital Coronary Artery Anomalies With Origin in the Contralateral Sinus of Valsalva: Which Approach Should We Take?, Revista Española de Cardiología (English Edition), 10.1016/S1885-5857(06)60773-1, 59:4, (360-370), Online publication date: 1-Apr-2006. Barriales-Villa R and de la Tassa C (2006) Anomalías congénitas de las arterias coronarias con origen en el seno de Valsalva contralateral: ¿qué actitud se debe seguir?, Revista Española de Cardiología, 10.1157/13087058, 59:4, (360-370), Online publication date: 1-Apr-2006. Barriales-Villa R, Morís C, Sanmartín J, Fernández E, Pajín F and Ruiz Nodar J (2006) Registro de anomalías congénitas de las arterias coronarias con origen en el seno de Valsalva contralateral en 13 hospitales españoles (RACES), Revista Española de Cardiología, 10.1157/13089750, 59:6, (620-623), Online publication date: 1-Jun-2006. Fedak P, David T, Borger M, Verma S, Butany J and Weisel R (2014) Bicuspid aortic valve disease: recent insights in pathophysiology and treatment, Expert Review of Cardiovascular Therapy, 10.1586/14779072.3.2.295, 3:2, (295-308), Online publication date: 1-Mar-2005. April 29, 2003Vol 107, Issue 16 Advertisement Article InformationMetrics https://doi.org/10.1161/01.CIR.0000067687.37985.C4PMID: 12719292 Originally publishedApril 29, 2003 PDF download Advertisement

We enjoyed reading Osawa and colleagues' article about histologic changes of biomaterials used to repair ventricular heart defects in small animals1Osawa T, Mickle D, Weisel R, Koyama, N, Wong H, Ozawa S, Li RK. Histologic changes of nonbiodegradable and biodegradable biomaterials used to repair right ventricular heart defects in rats. J Thorac Cardiovasc Surg. 2002;1241157-63Google Scholar as published in this Journal and also have followed this group's work elsewhere.2Yau T.M. Tomita S. Weisel R.D. Jia Z.Q. Tumiati L.C. Li R.K. Beneficial effect of autologous cell transplantation on infarcted heart function comparison between bone marrow stromal cells and heart cells.Ann Thorac Surg. 2003; 75: 169-177Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar Our own review on the current literature in this area has spawned many questions and suggestions for future study designs. Most published studies do not present clinically applicable, reparative options. We believe that a critical analysis of these studies with respect to geometry, physiology, and inflammatory and immunologic responsiveness of myocardium will help identify flaws in current study designs and also help define standardized quality criteria to guide future attempts to manufacture implantable myocardium. Few studies, for instance, have reliably and convincingly proved enhancement of cardiac function after induction of myocardial injury relative to control values. We frequently see distorting scaffolds “sitting” on the heart, or replacing previously beating muscle, and identify in most of the cases significant foreign-body reaction and reactive neovascularization3Eschenhagen T. Didie M. Heubach J. Ravens U. Zimmermann W.H. Cardiac tissue engineering.Transplant Immunol. 2002; 9: 315-321Crossref PubMed Scopus (64) Google Scholar interpreted as angiogenesis. Frequently the immunologic response to the implanted scaffold and the inoculated cells is neglected, even when species barriers are crossed. Furthermore, many study designs fail to adhere to well-described “hard problems” in the development of bioartificial myocardium: 1.With respect to cardiac geometry, the ventricular muscle constitutes a complex helical structure.4Buckberg G.D. Basic science review the helix and the heart.J Thorac Cardiovasc Surg. 2002; 124: 863-883Abstract Full Text Full Text PDF PubMed Scopus (191) Google Scholar Symmetric and isotropic matrices would promote scarring and aneurysm formation. The issues of asymmetry and anisotropy of the heart have never been addressed.2.With respect to cardiac hemodynamics, the modified law of Laplace for the heart **CWS = Pb/h × (1 − b2/2a2 − h/2b + h/8a2), where: CWS is circumferential wall stress (in dyne/cm2 × 103), P is left ventricular pressure (in dyne/cm2), a and b are major and minor semiaxes, respectively (in cm) and h is left ventricular wall thickness (in cm). defines circumferential wall stress values that would not be tolerated by most of the described matrices. Very likely these matrices would decompose, leading to severe hemorrhage, or would form aneurysms.**CWS = Pb/h × (1 − b2/2a2 − h/2b + h/8a2), where: CWS is circumferential wall stress (in dyne/cm2 × 103), P is left ventricular pressure (in dyne/cm2), a and b are major and minor semiaxes, respectively (in cm) and h is left ventricular wall thickness (in cm).3.With respect to microscopic structure, we are unaware of approaches that involve both including nerves (conductive microstructures) and preformed chaotic and plastic microchannnels simultaneously.4.With respect to issues of storage, conservation, and scale, an infant or child with congenital defects will most probably need a graft different from one destined to replace failing myocardium in a 75-year-old patient.5.With respect to the cells, Wagers and associates5Wagers A.J. Sherwood R.I. Christensen J.L. Weissman I.L. Little evidence for developmental plasticity of adult hematopoietic stem cells.Science. 2002; 27: 2256-2259Crossref Scopus (1280) Google Scholar have demonstrated that bone marrow stem cells have little developmental plasticity. Most of the tissue engineering approaches with bone marrow stem cells use whole bone marrow, rather than specific subpopulations of it, and they frequently lack identification of the inoculated cells because of missing labeling and reliable colocalization studies. What are we implanting? What happens to each particular cell population, and to what extent do these cells transdifferentiate into cardiomyocytes? Studies with myoblasts do no better. Reliability and interpretability of the results would be significantly enhanced if cell labeling and tracking methods would be used routinely. Some worth mentioning are the green fluorescent protein or carboxyfluorescein diacetate succinimidyl ester methods, the membrane fluorescent intercalated dye pkh26-gl method, and colocalization or confocal studies to identify cell identity, location, differentiation status and host immune response (Figure 1). The commentary of this group will certainly initiate fruitful discussion on basic requirements for future scientific approaches to restoring injured myocardium. Reply to the EditorThe Journal of Thoracic and Cardiovascular SurgeryVol. 126Issue 6Preview Full-Text PDF

BACKGROUND:Adipocyte-derived hormones may represent a mechanism linking insulin resistance to cardiovascular disease. In the present study, we evaluated the direct effects of resistin, a novel adipocyte-derived hormone, on endothelial activation.METHODS AND RESULTS:Endothelial cells (ECs) were incubated with human recombinant resistin (10 to 100 ng/ML, 24 hours), and endothelin-1 (ET-1) release, ET-1 mRNA expression, and nitric oxide (NO) production were assessed. Transient transfection assays were used to evaluate the effects of resistin on transcription of human ET-1 gene promoter. Furthermore, the effects of resistin on AP-1-mutated ET-1 promoter were evaluated. The effects of resistin on expression of vascular cell adhesion molecule (VCAM-1) and monocyte chemoattractant chemokine (MCP-1) were studied in addition to CD40 receptor, CD40 ligand-induced MCP-1 expression, and tumor necrosis factor receptor-associated factor-3 (TRAF3), an inhibitor of CD40 signaling. Incubation of ECs with resistin resulted in an increase in ET-1 release and ET-1 mRNA expression, with no change in NO production. Whereas treatment with resistin resulted in an increase in ET-1 promoter activity, the AP-1-mutated promoter was inactive after resistin stimulation. Additionally, resistin-treated cells showed increased expression of VCAM-1 and MCP-1, with concomitant reductions in TRAF-3 expression. Resistin did not alter CD40 receptor expression; however, increased CD40 ligand induced MCP-1 production.CONCLUSIONS:The novel adipokine resistin exerts direct effects to promote EC activation by promoting ET-1 release, in part by inducing ET-1 promoter activity via the AP-1 site. Furthermore, resistin upregulates adhesion molecules and chemokines and downregulates TRAF-3, an inhibitor of CD40 ligand signaling. In this fashion, resistin may be mechanistically linked to cardiovascular disease in the metabolic syndrome.