Nelson Itiro Miyague

Epidemiological study of congenital heart defects in children and adolescents: analysis of 4,538 cases

OBJECTIVE To analyze the frequency and prevalence of congenital heart defects in a tertiary care center for children with heart diseases. METHODS We carried out an epidemiological assessment of the first medical visit of 4,538 children in a pediatric hospital from January 1995 to December 1997. All patients with congenital heart defects had their diagnoses confirmed at least on echocardiography. The frequency and prevalence of the anomalies were computed according to the classification of sequential analysis. Age, weight, and sex were compared between the groups of healthy individuals and those with congenital heart defects after distribution according to the age group. RESULTS Of all the children assessed, 2,017 (44.4%) were diagnosed with congenital heart disease, 201 (4.4%) with acquired heart disease, 52 (1.2%) with arrhythmias, and 2,268 (50%) were healthy children. Congenital heart diseases predominated in neonates and infants, corresponding to 71.5% of the cases. Weight and age were significantly lower in children with congenital heart defects. Ventricular septal defect was the most frequent acyanotic anomaly, and tetralogy of Fallot was the most frequent cyanotic anomaly. CONCLUSION Children with congenital heart defects are mainly referred during the neonatal period and infancy with impairment in gaining weight. Ventricular septal defect is the most frequent heart defect.

Are purified or expanded cord blood-derived CD133+ cells better at improving cardiac function?

Endothelial progenitor cells (EPCs), which express the CD133 marker, can differentiate into mature endothelial cells (ECs) and create new blood vessels. Normal angiogenesis is unable to repair the injured tissues that result from myocardial infarction (MI). Patients who have high cardiovascular risks have fewer EPCs and their EPCs exhibit greater in vitro senescence. Human umbilical cord blood (HUCB)-derived EPCs could be an alternative to rescue impaired stem cell function in the sick and elderly. The aim of this study was to purify HUCB-derived CD133+ cells, expand them in vitro and evaluate the efficacy of the purified and expanded cells in treating MI in rats. CD133+ cells were selected for using CD133-coupled magnetic microbeads. Purified cells stained positive for EPC markers. The cells were expanded and differentiated in media supplemented with fetal calf serum and basic fibroblast growth factor, insulin-like growth factor-I and vascular endothelial growth factor (VEGF). Differentiation was confirmed by lack of staining for EPC markers. These expanded cells exhibited increased expression of mature EC markers and formed tubule-like structures in vitro. Only the expanded cells expressed VEGF mRNA. Cells were expanded up to 70-fold during 60 days of culture, and they retained their functional activity. Finally, we evaluated the therapeutic potential of purified and expanded CD133+ cells in treating MI by intramyocardially injecting them into a rat model of MI. Rats were divided into three groups: A (purified CD133+ cells-injected); B (expanded CD133+ cells-injected) and C (saline buffer-injected). We observed a significant improvement in left ventricular ejection fraction for groups A and B. In summary, CD133+ cells can be purified from HUCB, expanded in vitro without loosing their biological activity, and both purified and expanded cells show promising results for use in cellular cardiomyoplasty. However, further pre-clinical testing should be performed to determine whether expanded CD133+ cells have any clinical advantages over purified CD133+ cells.

Comparison of mononuclear and mesenchymal stem cell transplantation in myocardium infarction

Background: Bone marrow stem cell (SC) transplantation into failing myocardium has emerged as a novel therapeutic option for the treatment of ventricular dysfunction. Both mononuclear (MoSC) and mesenchymal (MeSC) stem cells have been proposed as ideal cell types to this goal. The objective of this study is to compare the efficacy of these cells in improving ventricular function in a rat model of postinfarct ventricular dysfunction. Method: Myocardial infarction was induced in Wistar rats by left coronary occlusion. After 1 week, 42 animals with resulting ejection fractions (EF) lower than 30% were included in the study. MoSC and MeSC were obtained from bone marrow aspirates and separated by the Ficoll-Hypaque method. MeSC were cultured for 14 days before injection. Nine days after infarction, rats received intramyocardial injections of MoSC (n=8), MeSC (n=13) or culture medium as a control (n=21). Echocardiographic evaluation was performed at baseline and after one month. Results: There were no significant differences in the baseline ejection fractions or the left ventricular end diastolic volumes (LVEDV) between all groups. After 1 month, ejection fraction decreased in the Control Group and remained unchanged in MoSC and MeSC Groups. In all three groups ventricular dilation was observed. Histopathology of the infarcted area where injections were performed identified new smooth muscle cells and endothelial cells in the MeSC Group and only new endothelial cells in MoSC Group Conclusions: Both MoSC and MeSC provided stabilization in the ejection fraction in this post-infarction ventricular dysfunction model however, no therapy prevented ventricular dilation.

Right ventricular diastolic dysfunction in the postoperative period of tetralogy of Fallot

OBJECTIVE To assess right ventricular diastolic function in the intermediate postoperative period of repair of tetralogy of Fallot. METHODS We carried out a case-control study with 60 patients divided into 2 groups as follows: 1) group I - 30 patients who had undergone repair of tetralogy of Fallot and 2) group II - 30 healthy children. The 2 groups were paired for age, sex, and body surface. The flows in the pulmonary and tricuspid valves were analyzed with Doppler echocardiography. The presence of anterograde flow at the end of diastole in the pulmonary artery defined restrictive right ventricular physiology. Surgical, radiological, electrocardiographic, and echocardiographic variables were analized in the group I. RESULTS The velocity of the A wave and the E/A ratio for the tricuspid valve showed significant differences between the groups. Cases with E/A < 1.30 predominated in inspiration (group I - 19/30, and group II - 5/30). The duration of the QRS complex on the electrocardiogram was significantly increased in patients with E/A <1.30. Nineteen (63.3%) patients had restrictive right ventricular physiology, which had a longer postoperative period, longer duration of the QRS complex, and a lower E/A ratio in inspiration. The surgical and radiological variables showed no statistical difference. CONCLUSION Restrictive right ventricular physiology was detected on the intermediate follow-up of most patients undergoing repair of tetralogy of Fallot. The postoperative period and QRS duration were increased in patients with impairment in diastolic function.

Transplantation of SNAP-treated adipose tissue-derived stem cells improves cardiac function and induces neovascularization after myocardium infarct in rats

Stem cell therapy has been considered a promise for damaged myocardial tissue. We have previously shown that S-nitroso-N-acetyl-D,L-penicillamine (SNAP) increases the expression of several muscular markers and VEGF in mesenchymal stem cells, indicating that transplantation of SNAP-treated cells could provide better functional outcomes. Here, we transplanted SNAP-treated adipose tissue-derived stem cells (ADSCs) in rat infarcted myocardium. After 30days, we observed a significant improvement of the ejection fraction in rats that received SNAP-treated ADSCs, compared with those that received untreated cells (p=0.008). Immunohistochemical reactions showed an increased expression of troponin T-C and von Willebrand factor, and organized vascular units in the infarcted area of tissue transplanted with treated ADSCs. SNAP exposure induced intracellular S-nitrosation, a decreased GSH/GSSG ratio, but did not increase cGMP levels. Collectively, these results indicate that SNAP alters the redox environment of ADSCs, possibly associated with a pre-differentiation state, which may improve cardiac function after transplantation.

O transplante em conjunto de células mioblásticas esqueléticas e mesenquimais (cocultivadas) na disfunção ventricular pós-infarto do miocárdio

OBJECTIVE: Cell therapy in the myocardium has been mainly performed with satisfactory results using 2 cell types: skeletal myoblasts (myogenic) and mesenchymal cells (angiogenic). This study assessed the combined transplantation of those 2 cell types (SMM) into infarcted rats. METHODS: Myocardial infarction was induced by ligature of the left coronary artery in 26 Wistar rats. After one week, the animals underwent echocardiography for assessing ejection fraction (EF%) and left ventricular end-diastolic and systolic volumes (EDV, ESV, mL). After 2 days, the animals were reoperated on and divided into 2 groups: 1) control (n=10), which received 0.15 mL of culture medium; and 2) SMM (n=16), which received 7.5x106 heterologous skeletal myoblasts and mesenchymal cells in the infarcted region. The cells were obtained from puncture of the iliac crest and biopsy of skeletal muscle, and were cultured in vitro. After one month, the animals underwent a new echocardiography. RESULTS: No significant difference in EF, EDV, and ESV was observed between the 2 groups on baseline echocardiographic values. One month after transplantation, the following was observed: a reduction in EF in the control group (29.31 ± 5.6% to 23.54 ± 6.51%; P=0.048); and an increase in EF in the SMM group (24.03 ± 8.68% to 31.77 ± 9.06%; P=0.011). The presence of neovascularization and muscle fibers was identified in the regions of myocardial fibrosis in the SMM group. CONCLUSION: Cocultivation of skeletal myoblasts and mesenchymal cells is functionally effective.

Evaluation of the biological behavior of decellularized pulmonary homografts: an experimental sheep model

INTRODUCTION The cryopreserved homograft is a good valve substitute due attributes like excellent hemodynamics, low incidence of thromboembolic events, infection resistance and good mid-term durability. However, progressive homograft degeneration and fibrocalcification may occur, particularly in the childhood and young adults. Their antigenicity triggers an immunological reaction that plays an important role in their degeneration and failure. The decellularization process was proposed to decrease this antigenicity. By the action of detergents and enzymes, this process removes all cellular components from the homograft matrix, diminishing immunogenicity and probably delaying its degeneration. OBJECTIVE The objective of this experimental and descriptive study is to evaluate the biological and functional behavior of decellularized pulmonary homografts (Decell-H), treated by a sodium dodecil sulfate solution (0.1%), developed in our University (Pontifícia Universidade Católica do Paraná). For the characterization of Decell-H performance, parameters like recellularization, calcification, and echocardiographic data will be analyzed. METHODS Eight juvenile sheep were submitted to the implantation of the Decell-H sutured into orthotopic position, through a left thoracotomy and with cardiopulmonary bypass support. They were followed-up clinically and by periodical echocardiograms until the explantation, which were performed in different time for every two sheep: seven, 30, 90 and 180 postoperative days. For histological analysis we used Hematoxilin-eosin, Movat and Alizarin-Red staining. RESULTS The sheep reached their follow-up period in a good clinical state. There was no valve regurgitation or stenonis by the echocardiogram. The animals submitted to the explantation in 90 and 180 days had a significant somatic growth and these Decell-H(s) had a diameter increase, without central valve insufficiency. Histologically, all homografts preserved their extra-cellular matrix organization and were progressively recellularized, without calcification. CONCLUSION In this experimental model, the Decell-H behaved as an excellent valve substitute.

Effect of exercise associated with stem cell transplantation on ventricular function in rats after acute myocardial infarction

OBJECTIVE To analyze the functional and anatomical-pathological effect of transplantation of bone marrow mononuclear cells associated to aquatic physical activity after myocardial infarction in rats. METHODS Twenty-one rats were induced by myocardial infarction, through left coronary artery ligation. After a week, the animals were subjected to echocardiography for evaluation of left ventricle ejection fraction (LVEF, %) and dyastolic and end systolic volume of the left ventricle (EDV, ESV, ml), randomized and the transplantation of mononuclear stem cells. The animals were divided into four groups: sedentary group without cells (n=5), sedentary with cells (n=5), trained without cells (n=5) and trained with cells (n=6). The physical training was started 30 days after infarction and held in swimming during 30 days. At the beginning and at the end of the physical training protocol were held assay of lactate. The animals have been subjected to new echocardiography after 60 days of myocardial infarction. RESULTS Two months after the transplant, were observed decrease in FE in the control group (35.2 to 23.54 P=0.022) and addition of LVEF and stabilization of ventricular remodeling in the group trained with cells (29.85 to 33.43% P=0.062 and 0.71 to 0.73 ml, P=0.776, respectively). Identified the reduction of collagen fibers, myocardial fibrosis regions in the group trained with and without cells. CONCLUSION The group trained with cells improves ventricular function compared to the control group, suggesting the benefit of associated cell therapy will physical activity.

Prenatal diagnosis of left ventricular aneurysm and diverticulum

We report two cases of localized left ventricular (LV) protrusion, an entity that has been described in the literature as aneurysm or diverticulum. Both cases had different outcomes from those previously reported. Little is known on the incidence and natural history of these rare anomalies, whose progression may be asymptomatic or lead to severe complications and death in the prenatal period. The therapeutic approach should be customized.Descrevemos dois casos de protrusao localizada do ventriculo esquerdo (VE), entidade que tem sido descrita na literatura como aneurisma ou diverticulo. Em ambos os casos, observou-se uma evolucao distinta da anteriormente relatada. A incidencia e historia natural dessas raras anomalias sao pouco conhecidas, podendo evoluir de forma assintomatica ou gerar graves complicacoes e ate o obito no periodo pre-natal. A abordagem terapeutica deve ser individualizada.

Avaliação ecocardiográfica evolutiva do infarto do miocárdio em ratos jovens e adultos

BACKGROUND: The regeneration of cardiomyocytes after a myocardial infarction (MI) is more evident in young animals; however, it is not known whether it is associated with functional improvement. OBJECTIVE: To perform the functional analysis by echocardiography (echo) of young adult rats submitted to MI. METHODS: Seventy-two animals were included in the study: 35 young rats (group Y) that were 28 days old and 37 adult rats (group A) that were 153 days old. The rats were subdivided in two subgroups: infarcted (YI and AI) and control (YC and AC). The animals were assessed by echocardiogram on the 7thand 30th postoperative days for the analysis of the ejection fraction (EF) and the final systolic (FSV) and diastolic volume (FDV) of the left ventricle. Only animals with EF < 40% were included in the study. RESULTS: The comparison of the FDV and FSV between infarcted and control animals showed that there was a significant increase in infarcted adult animals at the two analyzed phases. Among young animals only the FSV was significantly higher on the 7th day. The intragroup evolution analysis showed an increase in FDV and FSV in the two young subgroups, which was proportional to growth and only increase in FDV in the infarcted adult group. There was an improvement in EF in young rats, whereas EF remained decreased in adult rats when compared to controls. CONCLUSION: The infarcted young rats presented improvement in the systolic function and ventricular volumes 30 days after the infarction, whereas the adult rats presented increased FDV with no improvement in systolic function.