Hemodynamic contribution of stem cell scaffolding in acute injured myocardium

Tissue-engineered scaffolds may improve experimental outcomes in cardiac cell therapy by targeted delivery of stem cells and mechanically support an infarcted left ventricular (LV) wall. We transplanted cardiomyocyte-like cells (5×105) with scaffolding via epicardial patching (cell patch, n=17) or a low-dose intramyocardial hydrogel (LD hydrogel, n=18), a high-dose (5×106) intramyocardial hydrogel (HD hydrogel, n=18) or transplanting a serum-free medium control (control, n=13), a blank patch (n=14), and a blank gel (n=16) for targeted cardiomyoplasty in a myocardial infarcted rat model. LV real-time hemodynamics were assessed using a 1.9-F pressure–volume catheter 7 weeks after stem cell transplantation. All mode of scaffold transplantation protected diastolic function by preserving LV wall integrity that resulted in a lower end diastolic pressure–volume relationship (EDPVR) as compared to a control medium-injected group. Moreover, epicardial patching, but not hydrogel injection, reduced ventricular wall stress with a significantly better LV end diastolic pressure (EDP: 5.3±2.4 mmHg vs. 9.6±6.9 mmHg, p<0.05) as compared to control. Furthermore, epicardial patching additionally preserved systolic function by modulating negative remodeling through restricting dilatation of the LV chamber. In comparison to control, an improved ejection fraction in the cell patch group (80.1%±5.9% vs. 67.9%±3.2%, p<0.01) was corroborated by load-independent enhancement of the end systolic pressure–volume relationship (ESPVR: 0.88±0.61 mmHg/uL vs. 0.29±0.19 mmHg/uL, p<0.05) and preload recruitable stroke work (PRSW: 68.7±26.4 mmHg vs. 15.6±16.2 mmHg, p<0.05) in systolic function. Moreover, the cell patch group (14.2±1.7 cells/high-power field vs. 7.4±1.6 cells/high power field, p<0.05) was significantly better in myocardial retention of transplanted stem cells as compared to the LD hydrogel group. Collectively, myocardial transplantation of compliant scaffolding materials alone may physically improve wall mechanics, largely independent of stem cells. However, epicardially grafted cell patch conferred added systolic contractility by improving stem cell retention and cellular alignment leading to improved LV remodeling and geometric preservation postinfarction.Published Versio

Staging Cardiac Damage in Patients With Symptomatic Aortic Valve Stenosis

Background: In severe aortic stenosis (AS), patients often show extra-aortic valvular injury. Recently, a new staging system for severe AS has been proposed on the basis of the extent of cardiac damage. Objectives: The present study evaluated the prevalence and prognostic impact of these different stages of cardiac damage in a large, real-world, multicenter cohort of symptomatic severe AS patients. Methods: From the ongoing registries from 2 academic institutions, a total of 1,189 symptomatic severe AS patients were selected and retrospectively analyzed. According to the extent of cardiac damage on echocardiography, patients were classified as Stage 0 (no cardiac damage), Stage 1 (left ventricular damage), Stage 2 (mitral valve or left atrial damage), Stage 3 (tricuspid valve or pulmonary artery vasculature damage), or Stage 4 (right ventricular damage). Patients were followed for all-cause mortality and combined endpoint (all-cause mortality, stroke, and cardiac-related hospitalization). Results: On the basis of the proposed classification, 8% of patients were classified as Stage 0, 24% as Stage 1, 49% as Stage 2, 7% as Stage 3, and 12% as Stage 4. On multivariable analysis, cardiac damage was independently associated with all-cause mortality and combined outcome, although this was mainly determined by Stages 3 and 4. Conclusions: In this large multicenter cohort of symptomatic severe AS patients, stage of cardiac injury as classified by a novel staging system was independently associated with all-cause mortality and combined endpoint, although this seemed to be predominantly driven by tricuspid valve or pulmonary artery vasculature damage (Stage 3) and right ventricular dysfunction (Stage 4)