Antiheart antibody-dependent cytotoxicity in the sera of mice chronically infected with <i>Trypanosoma cruzi</i>

Sera of mice chronically infected with Trypanosoma cruzi contain antibodies that bind to the surface of living adult syngeneic heart muscle cells. In a syngeneic system, with nonadherent spleen mononuclear cells as effector cells and cardiocytes as targets, antibody-dependent cytotoxicity (ADCC), revealed by the liberation of creatine phosphokinase from damaged cardiocytes, was observed after incorporation of serum samples from infected mice. Target damage was decreased after absorption with syngeneic myocardium, but absorption with T. cruzi epimastigotes or trypomastigotes or with syngeneic skeletal muscle had no effect on ADCC. No complement-dependent lysis against heart muscle cells was detected in the same serum samples. These observations indicate that serum from chronically chagasic mice contain antibodies that bind to the surface of living adult syngeneic cardiocytes and are able to exert ADCC, suggesting that they could play a role in the pathogenesis of the heart damage that occurs in Chagas' disease.Facultad de Ciencias Médica

Presence of anti-<i>Trypanosoma cruzi</i> antibodies in the sera of mice with experimental autoimmune myocarditis

The existence of antigens shared in common by T. cruzi and heart muscle cells is suggested by the presence of antibodies binding to the parasite surface in the serum of mice with autoimmune myocarditis induced by immunization with syngeneic heart antigens.Facultad de Ciencias Médica

DNA content and expression of cell cycle proteins in caterpillar nuclei from fetal human cardiac myocytes

Caterpillar nuclei (CN) are characterized by their peculiar morphology, with chromatin distributed in clusters and running along the longitudinal axis of the nucleus. They can be observed in normal hearts of fetuses as well as in hearts of children and adults with rheumatic heart disease. This study has demonstrated by means of ploidy studies with digital image analysis that in the fetal heart (20.5±1.8 weeks) the CN (diploid = 5.6±8.4%; tetraploid = 46.2±24.2%; hypertetraploid = 46.9±26.3%) present higher DNA content than non-caterpillar myocyte nuclei (diploid = 89.4±6.2%; tetraploid = 10.0±4.1%; hypertetraploid = 1.5±1.3%) (P=0.000001, 0.00013, and 0.000038, respectively). Expression of proliferation cell nuclear antigen (PCNA; 30.6±11.7% in CN and 13.4±7.3% in non-caterpillar myocyte nuclei; P=0.0115) and cyclin B1 (2.8±3.8% and 12.6±15.6%, respectively; P=n.s.) was also positive in these nuclei. In conclusion, these results suggest that there exists a relationship between CN morphology and myocyte replication phenomena.Universidad Nacional de La Plat

Effect of vascular endothelial growth factor gene transfer on infarct size, left ventricular function and myocardial perfusion in sheep after 2months of coronary artery occlusion

Background: In large mammalian models of acute myocardial infarction (AMI), plasmid-mediated vascular endothelial growth factor (pVEGF) gene transfer has been shown to induce angio-arteriogenesis, proliferation of myocyte precursors and adult cardiomyocyte mitosis, reducing infarct size at 15days after coronary artery occlusion. However, it is unknown whether these effects persist at longer follow-up times, nor how they affect cardiac performance. We thus assessed infarct size, left ventricular (LV) function and perfusion in 2-month-old ovine AMI. Methods: Adult sheep with coronary artery occlusion were randomized to blindly receive ten intramyocardial injections of 3.8mg of pVEGF or empty plasmid distributed at the infarct border. Three and 60days later, LV perfusion (single-photon emission computed tomography) and function (stress echocardiography) were assessed. Finally, hemodynamics (LV catheterization), scar size and peri-infarct histology were studied. Results: Infarct size was 30% smaller in pVEGF-treated sheep (23.6±1.9% versus 32.7±2.7% of the LV; p<0.02). Percentage fractional shortening and wall thickening at the infarct border improved after pVEGF, as did myocardial perfusion and LV wall motion under pharmacological stress. Global LV function did not differ between groups, although the force-frequency response was preserved in pVEGF group and lost in placebo animals. These effects were associated with angio-arteriogenesis and proliferation of cardiomyocyte precursors. Conclusions: In sheep with AMI, pVEGF gene transfer affords long-term infarct size reduction, yielding regional LV function and perfusion improvement and reducing remodeling progression. These results suggest the potential usefulness of this approach in the clinical setting.Fil: Vera Janavel, Gustavo L.. Universidad Favaloro. Área de Investigación y Desarrollo; ArgentinaFil: De Lorenzi, Andrea. Fundación Favaloro; ArgentinaFil: Cortés, Claudia. Fundación Favaloro; ArgentinaFil: Olea, Fernanda Daniela. Universidad Favaloro. Área de Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cabeza Meckert, Patricia. Fundación Favaloro; ArgentinaFil: Bercovich, Andrés. Biosidus S. A.; ArgentinaFil: Criscuolo, Marcelo. Biosidus S. A.; ArgentinaFil: Laguens, Rubén. Universidad Favaloro. Área de Investigación y Desarrollo; ArgentinaFil: Crottogini, Alberto Jose. Universidad Favaloro. Área de Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Activated macrophages as a feeder layer for growth of resident cardiac progenitor cells

The adult heart contains a population of cardiac progenitor cells (CPCs). Growing and collecting an adequate number of CPCs demands complex culture media containing growth factors. Since activated macrophages secrete many growth factors, we investigated if activated isolated heart cells seeded on a feeder layer of activated peritoneal macrophages (PM) could result in CPCs and if these, in turn, could exert cardioprotection in rats with myocardial infarction (MI). Heart cells of inbred Wistar rats were isolated by collagenase digestion and cultured on PM obtained 72 h after intraperitoneal injection of 12 ml thioglycollate. Cells (1 × 106) exhibiting CPC phenotype (immunohistochemistry) were injected in the periphery of rat MI 10 min after coronary artery occlusion. Control rats received vehicle. Three weeks later, left ventricular (LV) function (echocardiogram) was assessed, animals were euthanized and the hearts removed for histological studies. Five to six days after seeding heart cells on PM, spherical clusters composed of small bright and spherical cells expressing mostly c-Kit and Sca-1 antigens were apparent. After explant, those clusters developed cobblestone-like monolayers that expressed smooth muscle actin and sarcomeric actin and were successfully transferred for more than ten passages. When injected in the MI periphery, many of them survived at 21 days after coronary ligature, improved LV ejection fraction and decreased scar size as compared with control rats. CPC-derived cells with cardiocyte and smooth muscle phenotypes can be successfully grown on a feeder layer of activated syngeneic PM. These cells decreased scar size and improved heart function in rats with MI.Facultad de Ciencias MédicasCentro de Investigaciones Cardiovasculare

Selectivity of alterations in skeletal fibers in chronic Chagas' disease of the mouse

In mice chronically infected withTrypanosoma cruzi, the masseter muscle (rich in type II fibers) was devoid of inflammatory infiltrates and parasites. In contrast, other muscles, composed of type I and II fibers, showed a decrease of type I fibers, parasites and lesions, suggesting that inT. cruzi infection type I muscle fibers are selectively damaged.Facultad de Ciencias Médica

Antiheart antibody-dependent cytotoxicity in the sera of mice chronically infected with <i>Trypanosoma cruzi</i>

Sera of mice chronically infected with Trypanosoma cruzi contain antibodies that bind to the surface of living adult syngeneic heart muscle cells. In a syngeneic system, with nonadherent spleen mononuclear cells as effector cells and cardiocytes as targets, antibody-dependent cytotoxicity (ADCC), revealed by the liberation of creatine phosphokinase from damaged cardiocytes, was observed after incorporation of serum samples from infected mice. Target damage was decreased after absorption with syngeneic myocardium, but absorption with T. cruzi epimastigotes or trypomastigotes or with syngeneic skeletal muscle had no effect on ADCC. No complement-dependent lysis against heart muscle cells was detected in the same serum samples. These observations indicate that serum from chronically chagasic mice contain antibodies that bind to the surface of living adult syngeneic cardiocytes and are able to exert ADCC, suggesting that they could play a role in the pathogenesis of the heart damage that occurs in Chagas' disease.Facultad de Ciencias Médica

Presencia de angiogénesis en placas vulnerables ateroscleróticas en corazones humanos aparentemente sanos

Background Angiogenesis or neovascularization involves the formation of new blood vessels adjacent to preexisting vessels. This vascular proliferation is prevalent in various clinical conditions, such as atherosclerosis. Microvessels in coronary artery atherosclerotic plaques may contribute to plaque instability. Objectives The aim of this study was to correlate the presence of angiogenesis in atherosclerotic plaques with the criteria of plaque vulnerability used by the American Heart Association (AHA). Methods One hundred and twenty one hearts from non-diabetic and apparently healthy transplant donors older than 40 years were selected. The coronary arteries were examined and all areas of cross-sectional luminal narrowing underwent histological, immunohistochemical and morphometric studies. A semi-quantitative score (scale 0-3) was used to identify of angiogenesis. Univariate and multivariate logistic regression analysis was performed to identify angiogenesis-related risk factors. Results On hundred and forty three high-risk lesions (AHA type IV, V and VI) in the left anterior descending coronary artery (46.3%), the circumflex coronary artery (28.9%) and the right coronary artery (43%) were identified. Angiogenesis had a statistically significant association with the severity of vascular occlusion, inflammatory cell infiltration, presence of a lipid core, fibrosis and periarteritis. A history of hypertension (HT) was associated with angiogenesis only in lesions of the left anterior descending coronary artery (LAD). According to the AHA classification angiogenesis was detected in 1 Type II, 5 Type III, 21 Type IV, 22 Type V, and 7 Type VI plaques. Conclusions Angiogenesis in vulnerable plaques was associated with the severity of vascular occlusion, inflammatory cell infiltration, fibrosis and presence of a lipid core, and with a history of HT in LAD lesions. There was no association between angiogenesis and plaque hemorrhage or calcification, suggesting that angiogenesis may anticipate plaque rupture.Introducción La angiogénesis o neovascularización involucra la formación de nuevos conductos en las adyacencias de vasos preexistentes. Esta proliferación vascular es frecuente en varias circunstancias clínicas, como es el caso de la aterosclerosis. Los microvasos de las placas ateroscleróticas coronarias pueden estar vinculados a la inestabilidad de la lesión. Objetivo Correlacionar la presencia de angiogénesis en placas ateroscleróticas con los criterios de vulnerabilidad de la clasificación de la American Heart Association (AHA). Material y métodos En 121 corazones de donantes no diabéticos aparentemente sanos y mayores de 40 años destinados para homoinjertos se examinaron las arterias coronarias y todas las áreas de estrechamiento luminal se sometieron a estudios histológicos, inmunohistoquímicos y morfométricos. Para el análisis de la angiogénesis se empleó un puntaje semicuantitativo (escala 0-3). Se realizó un análisis de regresión logística univariado y multivariado para identificar factores de riesgo relacionados con la angiogénesis. Resultados Se hallaron 143 lesiones de riesgo alto (AHA tipos IV, V y VI) en las arterias descendente anterior (46,3%), circunfleja (28,9%) y coronaria derecha (43%). La angiogénesis se asoció en forma estadísticamente significativa con el grado de oclusión vascular, la infiltración de células inflamatorias, la presencia de centro lipídico, la fibrosis, la periarteritis y, sólo en la descendente anterior, con el antecedente de hipertensión arterial (p < 0,006). Se detectó angiogénesis en 1 placa tipo II, en 5 tipo III, en 21 tipo IV, en 22 tipo V y en 7 placas tipo VI (AHA). Conclusiones La angiogénesis de placas vulnerables se asoció con el grado de oclusión vascular, la infiltración de células inflamatorias, la fibrosis, la presencia de núcleo lipídico y, sólo en la descendente anterior, con el antecedente de hipertensión arterial. No se encontró asociación con la hemorragia intraplaca o la calcificación, lo cual sugiere que la angiogénesis puede anticipar la rotura de las placas

Activated macrophages as a feeder layer for growth of resident cardiac progenitor cells

The adult heart contains a population of cardiac progenitor cells (CPCs). Growing and collecting an adequate number of CPCs demands complex culture media containing growth factors. Since activated macrophages secrete many growth factors, we investigated if activated isolated heart cells seeded on a feeder layer of activated peritoneal macrophages (PM) could result in CPCs and if these, in turn, could exert cardioprotection in rats with myocardial infarction (MI). Heart cells of inbred Wistar rats were isolated by collagenase digestion and cultured on PM obtained 72 h after intraperitoneal injection of 12 ml thioglycollate. Cells (1 × 106) exhibiting CPC phenotype (immunohistochemistry) were injected in the periphery of rat MI 10 min after coronary artery occlusion. Control rats received vehicle. Three weeks later, left ventricular (LV) function (echocardiogram) was assessed, animals were euthanized and the hearts removed for histological studies. Five to six days after seeding heart cells on PM, spherical clusters composed of small bright and spherical cells expressing mostly c-Kit and Sca-1 antigens were apparent. After explant, those clusters developed cobblestone-like monolayers that expressed smooth muscle actin and sarcomeric actin and were successfully transferred for more than ten passages. When injected in the MI periphery, many of them survived at 21 days after coronary ligature, improved LV ejection fraction and decreased scar size as compared with control rats. CPC-derived cells with cardiocyte and smooth muscle phenotypes can be successfully grown on a feeder layer of activated syngeneic PM. These cells decreased scar size and improved heart function in rats with MI.Fil: Sepúlveda, Diana Elizabeth. Universidad Favaloro; ArgentinaFil: Cabeza Meckert, Patricia. Universidad Favaloro; ArgentinaFil: Locatelli, Paola. Universidad Favaloro; ArgentinaFil: Olea, Fernanda Daniela. Universidad Favaloro; ArgentinaFil: Perez, Nestor Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Pinilla, Oscar Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Diaz, Romina Gisel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; ArgentinaFil: Crottogini, Alberto José. Universidad Favaloro; ArgentinaFil: Laguens, Rubén. Universidad Favaloro; Argentin

Long-term effects of growth hormone on infarct size and left ventricular function in sheep with coronary artery occlusion

The effects of growth hormone (GH) on infarct size and left ventricular (LV) function in experimental acute myocardial infarction (AMI) have been controversial. Moreover, little, if any, information exists regarding long-term evaluation of therapeutic doses of GH in large mammalian models of AMI. We therefore aimed to assess the effect of therapeutic doses of GH over 3.5 months on infarct size and heart function in sheep with AMI. After coronary artery ligation, sheep received subcutaneous human GH 8 IU/d (n = 8) or vehicle (n = 8) over 100 days. Infarct area was similar in GH (16.9% 6 3% of LV area) and placebo (16.5% 6 3.7%, P = not significant) sheep. At 3 days of treatment onset, but not at later times, GH sheep had higher LV shortening fraction (30.7% 6 3.5% vs. 24.8% 6 6.1%, P , 0.04), systolic anterior wall thickness (10.1 6 0.8 vs. 8.6 6 1.2 mm, P , 0.02), and cardiac index (3.8 6 0.6 vs. 2.8 6 0.7 L min21 m22 , P , 0.01). This evolution of function parameters paralleled that of serum insulin-like growth factor 1 levels, which differed significantly only during the first week, suggesting a direct effect of GH on LV contractility. These results may suggest the usefulness of therapeutic doses of GH at the early phases of AMI but do not support maintaining the treatment for longer time.Fil: Olea, Fernanda Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Favaloro; ArgentinaFil: De Lorenzi, Andrea. Universidad Favaloro; ArgentinaFil: Cortés, Claudia. Universidad Favaloro; ArgentinaFil: Cabeza Meckert, Patricia. Universidad Favaloro; ArgentinaFil: Cendoya, Oscar. Universidad Favaloro; ArgentinaFil: Barra, Juan G.. Universidad Favaloro; ArgentinaFil: Bercovich, Andrés. Biosidus S. A.; ArgentinaFil: González, Eliseo. Biosidus S. A.; ArgentinaFil: Laguens, Rubén. Universidad Favaloro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Crottogini, Alberto José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Favaloro; Argentin