Vera Demarchi Aiello

Immunohistochemical characterization of infiltrating cells in human chronic chagasic myocarditis: Comparison with myocardial rejection process

Cellular subpopulations that infiltrate the heart in human chronic chagasic myocarditis were defined immunohistochemically in endomyocardial biopsy (EMB) specimens. T cells formed 96.3% of the inflammatory infiltrate, predominantly CD8+ (cytotoxic/ suppressor) T cells. The mean numbers of CD8+ and CD4+ (helper) T cells in the myocarditis were compared to those present in the myocardial rejection process. Mean numbers of CD8+ T cells were similar in both groups of EMB specimens while CD4+ T cell counts, CD4+/CD8+ ratios and CD4+ antigen expression were significantly lower in the chagasic group compared to the myocardial rejection group (P<0.002). The persistent lower number and diminished expression of CD4+ T cells suggest an immunological imbalance in patients with chronic chagasic myocarditis. A possible participation ofTrypanosoma cruzi parasites in the development of such immunological abnormalities is also discussed.

Comparison between Adventitial and Intimal Inflammation of Ruptured and Nonruptured Atherosclerotic Plaques in Human Coronary Arteries

OBJECTIVEnTo verify the possible role of adventitial inflammation in atherosclerotic plaque vulnerability and coronary artery remodelling.nnnMETHODSnWe compared the mean numbers of lymphocytes in the adventitia and in the plaque of ruptured thrombosed and stable equi-stenotic coronary segments of 34 patients who died due to acute myocardial infarction. We also analysed adventitial microvessels, adventitial fibrosis and the external elastic membrane.nnnRESULTSnIn the adventitia, the numbers of lymphocytes and microvessels/mm2 were 69.5+/-88.3 and 60.9+/- 32.1 in culprit lesions and 16.4 +/- 21.1 and 44.3+/-16.1 in stable lesions (p<0.05); within the plaques, the mean number of lymphocytes was 24+/-40.8 in culprit lesions and 10.9+/-13.2 in stable ones (p=0.17). The mean percent area of adventitial fibrosis/cross-sectional area of the vessel was significantly lower in unstable plaques (p<0.001). The confocal images showed holes in the external elastic membrane.nnnCONCLUSIONnUnstable plaques exhibit chronic pan-arteritis, accompanied by enlargement, medial thinning, and less fibrosis than in stable lesions, which is compatible with vessel aneurysm. Adventitial inflammation may contribute significantly to atheroma instability.

Acute Chagas' disease: immunohistochemical characteristics of T cell infiltrate and its relationship with T. cruzi parasitic antigens.

Objective — The present work analysed endomyocardial biopsies of patients with acute Chagas’ disease in order to evaluate the frequency and intensity of T. cruzi antigens, CD4+ and CD8+ T cells to determine the characteristics of this recurrent disease in Venezuela. Material and methods — Twelve endomyocardial biopsies of patients with Chagas’ disease, 12 to 51 years old, (7M and 5F) were analysed. T. cruzi antigens and CD4+ (helper) and CD8+ (cytotoxicsuppressor) T cells were detected by the immunoperoxidase technique.The presence and intensity of lymphocytic myocarditis was evaluated according to the degree of myocardial fibre injury caused by inflammatory infiltrate. Results — Myocarditis was present in 100% of the cases.The mean numbers of CD4+ T cell and CD8+ T cell were 11.00 (± 10.29); 14.69 (± 13.08) and the CD4/CD8 T cell ratio was 0.75. T. cruzi antigens were detected in 58%. There was a good correlation between the numbers of CD4 and CD8 T cells of each case and a lack of correlation with the amount of T. cruzi antigens. Conclusion — All patients with acute Chagas’ disease show some degree of myocarditis that seems to be directly related to the presence of parasitic antigens. Both CD4 and CD8 T cells participate in this process.We are following these patients to see if patients with severe myocarditis and more parasite antigens in the acute phase will develop chronic heart failure.

Balloon Dilatation of the Aortic Valve in the Fetus

Fetal echocardiography has recently caused an impact on the treatment of congenital heart disease and in the field of therapeutic, cardiological intervention. The present study reports on a case of critical aortic stenosis, diagnosed in utero at 27 weeks gestation, and in which balloon dilatation was attempted to improve the poor prognosis associated with this condition. Since the endocardium at this stage of development was apparently normal, this therapeutic intervention was attempted to avoid irreversible damage to the left ventricle. Although hydrops disappeared and the myocardium hypertrophied, endocardial fibroelastosis progressed and the neonate died within the first day of life, after surgical aortic valvotomy. More data are necessary to clarify whether endocardial fibroelastosis is really a consequence of high pressure in the left ventricle resulting from stenosis of the aortic valve or whether it is a disease, the progression of which is unavoidable once it takes hold.

Coinfection with Mycoplasma Pneumoniae and Chlamydia Pneumoniae in Ruptured Plaques Associated with Acute Myocardial Infarction

OBJECTIVEnTo study atheromas, Mycoplasma pneumoniae (M. pneumoniae), and Chlamydia pneumoniae (C. pneumoniae).nnnMETHODSnC. pneumoniae was studied with immunohistochemistry and M. pneumoniae with in situ hybridization (ISH), in segments of coronary arteries (SCA) as follows: group A - thrombosed ruptured plaques (TRP) of 23 patients who died due to acute myocardial infarction (AMI); group B - 23 nonruptured plaques (NRP) of group A patients; group C - NRP of 11 coronary patients who did not die due to AMI; and group D - 11 SCA from patients with dilated cardiomyopathy or Chagas disease without atherosclerosis.nnnRESULTSnThe mean number of C. pneumoniae+ cells/400x in groups A, B, C, and D was, respectively, 3.3 +/- 3.6; 1.0 +/- 1.3; 1.2 +/- 2.4; and 0.4 +/- 0.3; and the percentage of M. pneumoniae area was, respectively, 3.9 +/- 3.5; 1.5 +/- 1.6; 0.9 +/- 0.9; and 0.4 +/- 0.2. More M. pneumoniae and C. pneumoniae were found in of group A than in group B (P<0.01). Good correlation was seen between the area of the vessel and the M. pneumoniae area in the plaque (r = 0.46; P=0.001) and between C. pneumoniae+ cells and CD4+ T lymphocytes (r = 0.42; P<0.01). The number of C. pneumoniae+ cells correlated with CD20+ B cells (r=0.48; P<0.01).nnnCONCLUSIONnM. pneumoniae and C. pneumoniae are more frequently found in TRP correlate with the intensity of the inflammation and diameter of the vessel (positive remodeling).

Percutaneous Transatrial Access to the Pericardial Space for Epicardial Mapping and Ablation

Background—Puncture of the atrial appendage may provide access to the pericardial space. The aim of this study was to evaluate the feasibility of epicardial mapping and ablation through an endocardial transatrial access in a swine model. Methods and Results—An 8-F Mullins sheath was used to perforate the right (n=16) or left (n=1) atrial appendage in 17 pigs (median weight, 27.5 kg; first and third quartiles [Q1, Q3], 25.2, 30.0 kg). A 7-F ablation catheter was introduced into the pericardial space to perform epicardial mapping and deliver radiofrequency pulses on the atria. The pericardial space was entered in all 17 animals. In 15 (88%) animals, there was no hemodynamic instability (mean blood pressure monitoring, initial median, 80 mm Hg; Q1, Q3, 70, 86 mm Hg; final median, 88 mm Hg; Q1, Q3, 80, 96 mm Hg; P=0.426). In these 15, a mild hemorrhagic pericardial effusion was identified and aspirated (median, 20 mL; Q1, Q3, 15, 30 mL) during the procedure, and postmortem gross analysis revealed that the atrial perforation was closed in these animals. In 2 (12%) of the 17 animals, there was major pericardial bleeding with hemodynamic collapse. On gross examination, it was found that pericardial space was accessed through right ventricular perforation in 1 animal and the tricuspid annulus in the other. After the initial study, we used an occlusion device in 3 other animals to attempt to seal the puncture (2 at the right atrial appendage and 1 at the right ventricle). These 3 animals had no significant pericardial bleeding. Conclusions—Transatrial endovascular right atrial appendage puncture may provide a potential alternative route for pericardial access. Further studies are needed to evaluate its safety with longer and more-complex procedures before being applied in clinical settings.

A histopathological comparison of different definitions for quantifying in-stent neointimal tissue: implications for the validity of intracoronary ultrasound and optical coherence tomography measurements.

PURPOSEnIntravascular ultrasound (IVUS) and optical coherence tomography (OCT) define neointima as the tissue encompassed between the stent and the lumen boundaries. This approach differs from the gold-standard histopathology, where neointima is traditionally calculated as the tissue between the internal elastic lamina (IEL) and the lumen. We aimed to investigate whether the neointimal assessment using IVUS and OCT-like definitions would correlate with the traditional histopathological quantification of neointima.nnnMETHODSnHistopathological analysis was obtained from a porcine model of 28-day coronary in-stent neointimal proliferation (n=13 bare stents). Traditional histopathology neointimal area (NIHPATH area) was calculated as the lumen area minus the IEL area, while the percent neointimal obstruction was defined as NIHPATH area divided by the IEL area. The IVUS/OCT-like neointima area (NIHIVUS/OCT area) was defined as the lumen area minus the stent area, while the percent neointimal obstruction was defined as NIHIVUS/OCT area divided by the stent area.nnnRESULTSnThe neointimal area as well as the percent obstruction were significantly correlated between histopathology and IVUS/OCT-like definitions (R(2)=0.89 and 0.95 respectively; P<0.01 for both). The average absolute difference between the IVUS/OCT-like and the pathology-like measurements was close to zero, however with a relatively wide dispersion (difference for neointimal area: 0.41 mm(2) [95% CI 1.72 to (-)0.90 mm(2)]; difference for percent neointimal obstruction: 2.5% [95% CI 11.5% to (-)6.5%]).nnnCONCLUSIONSnThe present findings support the use of stent area in replacement to IEL area, as in IVUS & OCT imaging protocols, for the calculation of neointimal parameters in experimental model of restenosis.

Endomyocardial fibrosis in infancy

The patient was a 4-month-old infant, who underwent persistent ductus arteriosus interruption with titanium clips at the age of 13 days and, since the age of 2 months, had crises of hypoxia and hypertonicity. After clinical investigation, the presence of pulmonary hypertension was confirmed and left ventricular inflow tract obstruction was suspected. The patient underwent surgical treatment at the age of 4 months, during which right and left ventricular endocardial fibrosis was identified. The fibrosis was resected, but the infant had an unfavorable clinical evolution with significant diastolic restriction and died on the sixth postoperative day. Anatomicopathological and surgical findings suggested endomyocardial fibrosis, although that pathology is very rare at the patients age.

Adventitial Layer Enlargement Correlates with the Percentage of Medial Thickness in Peripheral Pulmonary Arteries from Patients with Congenital Heart Defects

Arterial walls undergo modifications during the course of pulmonary hypertension, particularly in the medial and intimal layers, leading to progressive occlusion of the lumen. Adventitial layer enlargement has been described as being present in the experimental hypoxic model and in the persistent pulmonary hypertension of the newborn. It was suggested that this enlargement may be related to stimulating factors derived from the medial smooth muscle cells. This study was designed to verify if different degrees of medial hypertrophy are correlated to the volume density of the adventitial layer in pulmonary hypertension secondary to congenital heart defects. Reviewing 21 lung biopsies from patients with congenital heart defects, we concluded that there is a statistically significant positive linear correlation between the mean percentage of medial arterial thickness and the volume density of the adventitial layer in the biopsies showing isolated medial hypertrophy. On the other hand, in biopsies showing frequent intimal proliferative lesions and irregular medial layer hypertrophy the correlation coefficient was lower. These findings suggest that the adventitial layer participates in the arterial remodeling process in secondary pulmonary hypertension, and that its enlargement depends on the qualitative degree of pulmonary vaso-occlusive disease.

Quantification of lymphatic vessels in dilated and chronic chagasic cardiomyopathy

3 males). These samples were routinely processed and paraffin-embedded. Serial 4-µm sections were stained by hematoxylin and eosin, Masson’s trichrome or submitted to the immunohistochemical technique for the detection of lymphatic vessels. ImmunohistochemistryHistological sections were incubated with the monoclonal antibody D2-40 (Dako Corporation, CA) diluted 1:100, overnight, at 4Correspondencia: Luiz Alberto Benvenuti • Rua Madalena, 477/31 Vila Madalena 05434-090 São Paulo, SP Brasil E-mail: anpluiz@incor.usp.br Artículo recibido el 15/05/09; revisado recibido el 25/07/09; aceptado el 07/10/09. muestras del endomiocardio del ventrículo derecho normal de 11 individuos muertos por causas no cardiovasculares y sometidos a necropsia (promedio de edad: 50,82 ±15,39; 3 del sexo masculino). Estas muestras se procesaron rutinariamente y las incluyeron en parafina. Cortes seriados a 4 mm se colorearon con hematoxilina-eosina, tricrómico de Mason o sometieron a la técnica inmunohistoquímica para detección de vasos linfáticos.