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BACKGROUND: Perioperative corticosteroid use may reduce acute kidney injury. We sought to test whether methylprednisolone reduces the risk of acute kidney injury after cardiac surgery. METHODS: We conducted a prespecified substudy of a randomized controlled trial involving patients undergoing cardiac surgery with cardiopulmonary bypass (2007-2014); patients were recruited from 79 centres in 18 countries. Eligibility criteria included a moderate-to-high risk of perioperative death based on a preoperative score of 6 or greater on the European System for Cardiac Operative Risk Evaluation I. Patients (n = 7286) were randomly assigned (1:1) to receive intravenous methylprednisolone (250 mg at anesthetic induction and 250 mg at initiation of cardiopulmonary bypass) or placebo. Patients, caregivers, data collectors and outcome adjudicators were unaware of the assigned intervention. The primary outcome was postoperative acute kidney injury, defined as an increase in the serum creatinine concentration (from the preoperative value) of 0.3 mg/dL or greater (≥ 26.5 μmol/L) or 50% or greater in the 14-day period after surgery, or use of dialysis within 30 days after surgery. RESULTS: Acute kidney injury occurred in 1479/3647 patients (40.6%) in the methylprednisolone group and in 1426/3639 patients (39.2%) in the placebo group (adjusted relative risk 1.04, 95% confidence interval 0.96 to 1.11). Results were consistent across several definitions of acute kidney injury and in patients with preoperative chronic kidney disease. INTERPRETATION: Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery. Trial registration: ClinicalTrials.gov, no. NCT00427388. ispartof: CANADIAN MEDICAL ASSOCIATION JOURNAL vol:191 issue:9 pages:E247-E256 ispartof: location:Canada status: published

Understanding aortic root in vivo biomechanics can help in elucidating key mechanisms involved in aortic root pathologies and in the outcome of their surgical treatment. Numerical models can provide useful quantitative information. For this to be reliable, detailed aortic root anatomy should be captured. Also, since the aortic root is never unloaded throughout the cardiac cycle, the modeled geometry should be consistent with the in vivo loads acting on it. Achieving such consistency is still a challenge, which was tackled only by few numerical studies. Here we propose and describe in detail a new approach to the finite element modeling of aortic root in vivo structural mechanics. Our approach exploits the anatomical information yielded by magnetic resonance imaging by reconstructing the 3-dimensional end-diastolic geometry of the aortic root and makes the reconstructed geometry consistent with end-diastolic loading conditions through the estimation of the corresponding prestresses field. We implemented our approach through a semiautomated modeling pipeline, and we applied it to quantify aortic root biomechanics in 4 healthy participants. Computed results highlighted that including prestresses into the model allowed for pressurizing the aortic root to the end-diastolic pressure while matching the image-based ground truth data. Aortic root dynamics, tissues strains, and stresses computed at relevant time points through the cardiac cycle were consistent with a broad set of data from previous computational and in vivo studies, strongly suggesting the potential of the method. Also, results highlighted the major role played by the anatomy in driving aortic root biomechanics.

Chronic ischemic heart disease is characterized by an imbalance between cardiac cell death and regeneration. The local non-invasive activation of cardiac stem cells offers the possibility to influence the course of cardiomyopathy and to inhibit or reverse the pathological remodelling. In patients with coronary artery disease, low energy shock wave (SW) therapy was found to improve symptoms and ameliorate ischemia. The aim of our study was to evaluate the effects of SW on cardiac resident primitive cells in vitro. CD117(+) cells were isolated from the atria of adult human normal (n=7, males, mean age 51±5.6 years) and pathological hearts with ischemic cardiomyopathy (n=11, males, mean age 55±3.2 years), and treated with 800 shots of SW at the energy flux density of 0.05mJ/mm². Phospho-MAPK protein expression was assayed with proteome profiler array after 1 hour and total mRNA was examined by signal transduction specific PCR-based array 72 hours after the treatment. Gene expression profiling revealed in CD117(+) cells from pathological heart the down-regulation of genes relevant to the hedgehog pathway (EN1, BMP4, FOXA2), that is active in the early stages of the developmental process, or belonging to the induction and positive regulation of programmed cell death functional groups (CDKN2A, CDKN2B, CDKN1A, TP53I3, TNF), while the transcriptionally up-regulated genes included CSF2, CCL20, BIRC3, IL8, and IL1A that are involved in NFκB survival pathway and CEBPB, HK2, LEP involved in insulin pathway and myogenesis. Although SW treatment resulted in the significant increase in phospho-ERK1/2 in both cell populations, the phosphorylation of its downstream substrate RSK1 increased only in the normal cells. Similarly, in the normal cells the phosphorylation of p38-MAPKα, β and γ increased 4, 4-, 1, 2- and 4,2-fold, respectively, while only 1,3- and 2,2-fold increase in phosphorylated p38α and γ was observed in pathological cells. Moreover, the prosurvival kinase Akt1 resulted activated only in the normal cells. We conclude that the application of SW activates survival pathways and protects from apoptosis, although different signal transduction pathways can be responsible for these effects in cardiac primitive cells from normal and pathological heart with ischemic cardiomyopathy.

Cardiac Stem Cells (CSCc) contributing to cell turnover have been recently described in adult heart. The expression of extracellular matrix (ECM) proteins changes in qualitative and quantitative manner during heart remodeling. However, the influence of these changes on CSCs biology awaits investigation. The scope of the study was to evaluate the influence of fibronectin, laminin-1 and -2, collagen IV and of the natural ECM (cardiogel), obtained by culturing cardiac fibroblasts (CFs) isolated from normal (n=7) and pathological (n=8) hearts, on the biology of normal CSCs. Proliferation of CSCs, evaluated by BrdU incorporation, was 6,3-fold higher in the presence of laminin-1 and only 2-fold higher on laminin-2 with respect to control albumin. Apoptosis, detected in TUNEL assay, was as low as 1,8±0,4% on laminin-1 and was 2,8-fold, 5,4-fold and 8,5-fold higher on laminin-2, fibronectin and collagen IV, respectively. As revealed by immunofluorescence and immunoblotting, normal CFs synthesized mainly laminin-2, while pathological CFs produced more laminin-1, fibronectin, collagen IV and tenascin C. Interestingly, proliferation rate of CSCs on pathological cardiogel was 5,7-fold higher than that in the presence of normal cardiogel. In the similar manner, components of ECM from pathological heart diminished apoptosis rate with respect to cardiogel from normal heart. To assess the role of ECM on CSCs biology, we investigated the expression of and the signaling mediated by integrins. Noticeably, CSCs expressed mainly alpha-6 and alpha-2 integrin when cultured on pathological cardiogel and beta-3 integrin on normal cardiogel and, when interfering with integrin-mediated signals by specific function blocking antibodies, alpha-2 and beta-3 integrin resulted implicated in the stimulation of CSCs proliferation, while alpha-6 and alpha-2 in the protection of CSCs from apoptosis. We conclude that the components of ECM, responding to the physiological changes during heart remodeling, have profound effects on CSCs. These results should be taken into consideration when planning stem cells transplantation in the diseased hearts, since the microenvironment may determine the fate of the injected cells.

According to recent findings, pathological processes may deplete adult heart of stem cells. The scope of the present study was to assess proliferation, apoptosis and commitment of cardiac stem cells (CSCs) resident in normal (n=11) and pathological hearts with ischemic cardiomyopathy (n=20). Immunofluorescence and immunoblotting of CSCs isolated from normal and pathological hearts revealed higher expression of cardiac-specific markers in the latter. Proliferation of CSCs isolated from pathological hearts was 3.2±0.7-fold higher, while apoptosis induced by oxidative stress was 1.8±0.2-fold higher than in the normal cells. Asymmetric division, with unequal Notch distribution between daughter cells, occurred frequently in CSCs from ischemic hearts, while symmetric division was typical of normal cells. Gene expression was examined by stem cells specific PCR-based microarray. We confined our analysis to genes with at least 1.7-fold differential expression. Genes downregulated in pathological hearts belonged to the early stages of developmental process (snail1 homolog, jagged-1, ephrin b1), cell cycle control (mdm2, p15 and p16), neurogenesis, skeletal development, bone remodeling and cartilage development functional classes. Upregulated genes, among which OTF2, endothelin receptor, CD105 and MRG1, were involved in developmental maturation, mesenchymal cell differentiation, heart development and circulatory system processes. Major finding emerging from the analysis was the activation of the epithelial-mesenchymal transition and the upregulation of its inducer, TGFβ. The expression of genes related to TGFβ BMP-mediated signal transduction pathway was examined by PCR Array. The analysis confirmed the upregulation of genes as TGFβ-1 and -3, Nodal, ID1 and c-Myc, suggesting the activation of mesenchyme formation and CSCs differentiation towards cardiac cell lineages. In conclusion, CSCs in the normal and in the pathological heart differ in several respects and the differences reflect the activation of cardiac stem cells pool in the chronic pathological conditions. Given the apparent failure of intrinsic heart regeneration, further studies are warranted to optimize the strategies for CSCs application in regenerative medicine.

The RIFLE classification, which defines three grades of increasing severity of acute kidney injury--risk (RIFLE R), injury (RIFLE I) and failure (RIFLE F), and two outcome classes (L, loss) and E (end-stage kidney disease)--represents a valuable method for evaluating acute renal failure. Risk factors for acute kidney injury (AKI) according to the RIFLE criteria and for operative mortality were identified in patients undergoing valvular procedures.A single-center prospective cohort study of 1424 patients who were not receiving renal replacement therapy preoperatively was conducted between January 2004 and December 2007. A total of 100 variables was collected from each patient.The main features were: mean age 61.9 +/- 12.9 years (range: 15-88 years), 47% females, 6% endocarditis, 11% redo surgery, 8% urgent/emergent surgery, 30% combined procedures, 5% complex, and 16% associated coronary artery bypass grafting (CABG). The overall AKI prevalence was 10%, with RIFLE scores of I or F being detected in 8% and continuous veno-venous hemofiltration being required in 5%. Risk factors for AKI were age (OR 1.03; 95% CI 1.14-4.15), time of extracorporeal circulation (ECC) (OR 1.09; 95% CI 1.005-1.013), redo procedure (OR 2.35; 95% CI 1.42-3.8), chronic kidney disease (OR 3.2; 95% CI 1.6-6.1), and blood transfusion (OR 3.8; 95% CI 2.5-6.5). The transfusion of leukodepleted blood exerted a protective effect on AKI development (OR 0.6; 95% CI 0.4-0.9). The average overall hospital mortality was 4.8%. Risk factors for operative mortality included: ECC time (OR 1; 95% CI 1.002-1.014), age (OR 1.043; 95% CI 1.01-1.07), chronic kidney disease (OR 4.8; 95% CI 2.2-10.6), blood transfusion (OR 6.43; 95% CI 2.8-14.7), surgical priority (OR 6.5; 95% CI 2.8-14.7), RIFLE class I (OR 11.9; 95% CI 5.5-25.7), and RIFLE class F (OR 30; 95% CI 8.1-111.7). Mortality increased with each RIFLE stratification (Normal 1.7%, RIFLE R = 4.1%, RR = 2.5; RIFLE I = 27.6%, RR = 16.2; and RIFLE F = 43.8% RR = 25.8).AKI is a highly prevalent and prognostically important complication, for which the majority of risk factors that have been identified are not modifiable. The transfusion of leukodepleted blood products was seen to exert a preventive effect.

According to recent hypothesis, pathological processes may deplete the heart of stem cells and uncertainty still prevails as to whether functionally competent primitive cells can be obtained also from failing hearts. The scope of the present study was to assess proliferation, apoptosis, differentiation and commitment of cardiac primitive cells resident in normal (n=8) adult human hearts and in hearts with ischemic cardiomyopathy (n=8). Immunofluorescence and immunoblotting of CD117(+) cells isolated from normal and pathological hearts revealed higher expression of cardiac-specific nuclear and cytoplasmic markers in the latter. Proliferation of CD117(+) cells isolated from hearts with ischemic cardiomyopathy was 3.2±0.7-fold higher (p‹0.005), while the apoptosis induced by oxidative stress was 1.8±0.2-fold higher (p‹0.005) when compared with cells from normal hearts. Gene expression was examined by stem cells specific PCR-based microarray. We confined our analysis to genes with at least a 1.7 fold differential expression and identified 38 downregulated and 39 upregulated genes in CD117(+) cells from failing hearts. The downregulated genes included snail1 homolog, jagged-1 and ephrin b1 that are involved in the early stages of the developmental process; mdm2, p15 and p16 belonging to the cell cycle control functional group, as well as genes from the neurogenesis, skeletal development, bone remodeling and cartilage development functional classes. Upregulated genes, among which OTF2, endothelin receptor, CD105 and MRG1, were involved in developmental maturation, mesenchymal cell differentiation, heart development and circulatory system processes. One major finding emerging from the analysis is the acquired capability of cells from pathological heart of responding to wounding, as well as the upregulation of the response to external stimuli and stress. In comparison with normal cells, those from pathological heart become readily committed to cardiac cell lineages, at the expense of stemness and multipotentiality. Moreover, the epithelial-mesenchymal transition (EMT), which has been proposed as the mechanism behind cardiac stem cells origin, resulted activated, as well as known inducers of EMT, TGFβ and HGF signaling pathways. Cardiac stem cells in the normal and in the pathological heart differ in several respects and the differences reflect the activation of cardiac stem cells pool in the chronic pathological conditions. Given the apparent failure of intrinsic heart regeneration, further studies are warranted to optimize the strategies for cardiac stem cells application in regenerative medicine

The notion of the presence of stem and progenitor cells in the adult human heart imposes that all currently used treatments, as well as those in the experimental phase of the study, should be revisited with regards to effects on these cardiac cell population. In fact, novel therapies offer the possibility of inhibition or even reversal of heart failure progression by the mobilization and activation of cardiac stem and progenitor cells, as can be the case with extracorporeal cardiac shock wave (SW) therapy, suggested for patients with myocardial ischemia. The scope of the present study was to evaluate the effects of low and high energy SW treatment on cardiac primitive cells in vitro. CD117(+) cells have been isolated from age-matched adult human normal (n=4, males, mean age 51±5.6 years) and pathological hearts with end-stage ischemic cardiomyopathy (n=4, males, mean age 55±3.2 years). Cells have been treated with 800 shots of SW at the energy flux density of 0.05mJ/mm2 and 0.1mJ/mm2. After one week of culture, cardiac cell lineages were characterized by immunofluorescence and immunoblotting, and their total mRNA was examined by stem cell-specific PCRbased microarray. Above all, the effects of high energy treatment differed profoundly from those observed at low energy, with none the same gene up- or downregulated in any of the groups studied. Moreover, cells isolated from pathological hearts were positively influenced in the more evident manner. In fact, low energy treatment of pathological cells induced the activation of a pool of transient amplifying progenitors of cardiomyocytes (expressing α-sarcomeric actin), endothelial (von Willebrand factor) and smooth muscle cells (smooth muscle actin). In these cell population, we observed the upregulation of mRNA of 14 genes involved in the cytoskeleton biogenesis/organization, mitotic spindle formation and cell motility. In contrast, high energy SW application resulted in upregulation of 5 genes, mostly involved in the extracellular matrix- and cell-cell adhesion, and downregulation of 15 genes regulating protein kinase activity, signal transduction and cell-cell signalling. As regards cells from normal heart, remarkably only high energy treatment induced activation of endothelial cell precursors. On the basis of the above data it is possible to predict that timing (between onset and end-stage of disease) and energy of the SW treatment can have profound influence on the therapy outcome in ischemic heart disease. Further pre-clinical studies of these variables are warranted before broad introduction of the method into clinical practice.

Growing number of studies indicate epicardium-derived cells (EPDCs) as cardiac stem cells. While it is beyond doubt that these cells contribute to the normal developmentof the heart during organogenesis, it remains an open question whether mesothelial epicardial cells can undergo epithelial–mesenchymal transition, giving origin to cardiac primitive cells, in the adult human heart. We examined epicardium and subepicardium of the atria of human adult normal (n=11, mean age 41±12 years, 7 males, 4 females) and pathological hearts with chronic heart failure due to ischemic cardiomyopathy (n=22, mean age 55±5.5 years, 14 males, 8 females, mean ejection fraction 25±1%). Strikingly, only the normal adult human hearts were layered with epicardial cells. On the contrary, cell nuclei were absent from the surface lining of the diseased hearts. While normal epicardium resulted positive for cytokeratin 5/6, E-cadherin and Bves, in the pathological hearts the cells with epithelial markers were distributed among loose connective tissue of the subepicardium. Remarkably, these cells were CD117-positive and, when compared with subepicardium of normal heart, their number was 8.7-fold (p‹0.005) higher in the subepicardium of hearts with ischemic cardiomyopathy. In the PCR-based array of CD117-positive cells isolated from normal and pathological hearts, TGFβ and HGF receptor signaling pathways (both known inducers of EMT) resulted activated in the latter. Considering the hypothesis that EPDCs contribute to the cardiac CD117-positive cells population in the adult heart, fragments of epicardium of adult human cardiac atria were cultured on the extracellular matrix produced by cardiac fibroblasts, to obtain the outgrowth of the mesothelial cells forming epithelial sheets. When stimulated with TGFβ and HGF, intercellular contacts were lost and cells acquired mesenchymal characteristics and CD117 expression. Altogether, these results indicate that EPDCs enrich the pool of cardiac primitive cells that contribute to the regenerative properties of the adult human heart. It could be reasonably argued that CD117-positive and EPDCs represent the same primitive cell population.

Doxorubicin is one of the most active anti-cancer drugs, widely used for the treatment of several malignancies, however its clinical implementation is limited by high incidence of cardiovascular events, most serious of them being the cardiomyopathy followed by congestive heart failure. Known studies of the mechanisms of doxorubicin toxicity focused on cardiomyocyte damage. But then cardiac primitive cells are considered to provide the adult heart with a substantial growth reserve determining the function of the heart throughout life. The role of this cell population in the myocardial response to different pathologic stimuli has been documented in animals and humans, suggesting cardiac primitive cells as possible pathophysiologic target in cardiac diseases. We advance the hypothesis that cardiotoxicity of doxorubicin may be due to its effects on cardiac primitive cells. Hence, we examined doxorubicin toxicity on this cell population. CD117-positive cells isolated from adult human normal atria were incubated with increasing concentrations of doxorubicin hydrochloride (0.1, 0.5 and 1μM), followed by the evaluation of proliferation and apoptosis after 12, 24, 48 and 60 hours. Proliferation was evaluated by BrdU incorporation and its rate dropped from 12.84±1.83% (control, n=4) to 2.41±0.27% (24 hours, 1μM, n=4, p

The cumulative dose-dependent toxicity of doxorubicin, with the late development of the chronic heart failure that does not respond to digitalis, imposes serious limits on cancer treatment and often leads to heart transplantation in relatively young patients. Known studies of the mechanisms of doxorubicin toxicity focused on cardiomyocytes damage. According to the new notion of cardiac tissue biology, cardiac primitive cells are considered to provide the adult heart with a substantial growth reserve determining the function of the heart throughout life. Hence, numerous factors that can influence the subtle balance between cardiac primitive cells death and survival, can be implicated in the development and progression of cardiomyopathy and heart failure. The scope of the study was to examine the effects of doxorubicin on human adult CD117-positive cardiac primitive cells in vitro. Moreover, the role of dexrazoxane, a chelating agent with cardioprotective action, was revisited with respect to the reduction of doxorubicin toxicity on cardiac primitive cells. CD117-positive cells were incubated with increasing concentrations of doxorubicin hydrochloride (0,1; 0,5 and 1,0μM), followed by the evaluation of proliferation and apoptosis after 12, 24 and 48 hours. Proliferation was evaluated by BrdU incorporation and it decreased at all time-points, with the most significant effects after 24 hours, when its rate dropped from 12,84±1,83% (n=4) to 2,41±0,27% (n=4, p