Ultrastructure features of coronary artery endothelium in bactrian camel (Camelus bactrianus) / Características ultraestructurales del endotelio de las arterias coronarias en el camello bactriano (Camelus bactrianus)

Vascular endothelium play an essential role in regulating endothelial functions by maintaining normal vascular tone, modulating hemostasis, and preventing thromobogenesis. The aim of present study was to reveal ultrastructure features of coronary artery endothelium in Bactrian Camels by means of scanning electron microscope (SEM) technology. The results showed that the endothelial cells distribute along the direction of blood flow. Their morphology and protuberant degree towards luminal surface vary for different parts of the coronary artery. The luminal surface of a.c oronaria sinistra and a. coronaria dextra was covered by impaired and intact endothelium, respectively. Platelets and leukocytes sticking to the endothelium were found.

Las células endoteliales de los vasos sanguíneos juegan un rol esencial en la regulación de las funciones endoteliales manteniendo el tono vascular, modulando la homeostasis y previniendo la trombogénesis. En la investigación se utilizó un microscopio electrónico de barrido, revelando las características estructurales de las células endoteliales de los vasos coronarios de los camellos bactrianos. Los resultados indican que las células endoteliales estaban distribuidas a lo largo de la dirección de flujo. En distintas partes de la arteria coronaria existen diferencias en el grado de proyección de la morfología y de la superficie de la cavidad de dichas células. La superficie luminal de la arteria coronaria izquierda y la arteria coronaria derecha estaban cubiertas por endotelio deteriorado e intacto, respectivamente. Se observó adhesión de leucocitos y plaquetas en la superficie de las células endoteliales.

Morphological Analysis of Major Segments of Coronary Artery Occlusion: Importance in Myocardial Revascularization Surgery / Análisis Morfológico de los Principales Segmentos de Oclusión de las Arterias Coronarias: Importancia en la Cirugía de Revascularización Miocárdiaca

Revascularization surgery should ensure morphological similarity between the coronary artery and the graft. This is an important factor for its duration and permeability. The aim of this study was to analyze the morphological characteristics and morphometrics of the coronary artery segments with greater occlusion. This was an observational, cross-sectional descriptive study that consisted of two phases. A macroscopic phase in which 11 cadaveric hearts were extracted and coronary dominance and length of the anterior interventricular artery (AIA), the right coronary artery (RCA) and the circumflex artery (CXA) were determined. In the microscopic phase a total of 77 segments of these arteries were obtained and the luminal diameter, wall thickness, and amount of elastic fibers and the presence and size of the atheroma were determined. Right coronary dominance was the most frequent. Total vessel length was 15.65±1.17 cm for the AIA, 12.67±2.02 cm for the RCA and 8.79±2.5 cm for the CXA. Diameters ranged from 2.3 mm in the proximal segments and between 1.1 mm to 1.8 mm in the distal segments. Wall thickness in the proximal segments was between 354 µm and 396 µm and in the distal segments it ranged from 120 µm to 305 µm. The amount of elastic fibers showed that they were muscular arteries. Atheromas were present in 35% in the CXA, and in 32.5% in the AIA and the RCA. The largest ones were found in the proximal segments. This study examined the morphology and morphometry of the segments of the coronary arteries that are more frequently occluded. It provides information on the most significant parameters to be considered for election of the vascular graft in myocardial revascularization surgery.

En la cirugía de revascularización miocárdica se debe asegurar la similitud morfológica entre la arteria coronaria y el injerto. Esto es un factor importante en su duración y permeabilidad. El objetivo fue analizar las características morfológicas y morfométricas de los segmentos de mayor oclusión de las arterias coronarias. Estudio observacional, transversal y descriptivo que constó de dos fases. Una macroscópica en la que se extrajeron 11 corazones de cadáveres y se determinó la dominancia coronaria y longitud de la arteria interventricular anterior (AIA), la arteria coronaria derecha (ACD) y la arteria circunfleja (ACX). En la fase microscópica se obtuvo un total de 77 segmentos de estas arterias y se determinó el diámetro luminal, grosor de pared, cantidad de fibras elásticas y presencia y tamaño de ateroma. La dominancia coronaria derecha fue la más frecuente. La longitud total de los vasos fue de 15,65±1,17 cm para la AIA, de 12,67±2,02 cm para la ACD y 8,79±2,5 cm para la ACX. Los diámetros oscilaron entre los 2,3 mm en los segmentos proximales y entre 1,1 mm a 1,8 mm en los segmentos distales. Los grosores de pared en los segmentos proximales se presentaron entre 354 µm y 396 µm y en los segmentos distales oscilaron entre 120 µm a 305 µm. La cantidad de fibras elásticas demostró que son arterias musculares. El 35% de los ateromas se presentó en la ACX y el 32,5% en la AIA al igual que en la ACD. Los de mayor tamaño se encontraron en los segmentos proximales. Este estudio analizó la morfología y la morfometría de los segmentos de las arterias coronarias que se ocluyen con mayor frecuencia. Los resultados encontrados aporta información sobre los parámetros más significativos que se deben considerar para la elección del injerto vascular en la cirugía de revascularización miocárdica.

Ponte miocárdica associada a lesões cardiovasculares em bovinos adultos da raça Canchim / Myocardial bridge associated with cardiovascular injuries in bovines adult of Canchim race / Puente miocárdico asociado a lesiones cardiovasculares en bovinos adultos de la raza canchim

FUNDAMENTO: A influência que a ponte miocárdica exerce sobre a corrente sanguínea no curso do segmento arterial sob a ponte tem sido objeto de discussão pela comunidade científica. OBJETIVO: Comparar o tecido muscular ultraestrutural da ponte miocárdica e a parede ventricular; analisar o grau de lesão da camada íntima dos segmentos arteriais e investigar possíveis mudanças que podem preceder ou iniciar o processo de lesões ateroscleróticas. MÉTODOS: Quarenta corações bovinos da raça Canchim foram estudados em relação às alterações da camada íntima das artérias coronarianas nos diferentes segmentos de ponte miocárdica. Para o exame microscópico, foram feitas colorações por hematoxilina-eosina e fucsina-resorcina seguindo técnicas microscópicas convencionais. Para o exame de microscopia eletrônica, os segmentos da ponte miocárdica de doze corações bovinos Canchim foram coletados a partir da parede ventricular e da artéria coronariana e foram processados de acordo com técnicas convencionais. RESULTADOS: Na microscopia de luz, foi observada maior frequência de lesões em segmentos pré-ponte e pós-ponte da camada íntima, em comparação ao segmento ponte. Espessamentos da camada íntima foram seguidos por um desarranjo na lâmina limitante elástica interna. Essas células frequentemente apresentaram seus citoplasmas ingurgitados por gotas lipídicas, compondo as chamadas células de espuma. A microscopia eletrônica revelou que as fibras musculares da ponte miocárdica geralmente se unem de forma reta e lisa apresentando ramos laterais com um número maior de mitocôndrias no músculo ventricular do que na ponte. CONCLUSÃO: Há poucas diferenças entre os tecidos musculares estudados; lesões da camada íntima são menos frequentes em regiões da ponte em comparação com as regiões pré e pós-ponte.

BACKGROUND: The influence that myocardial bridge exercises over blood stream in the course of arterial segment under the bridge has been discussed by the scientific community. OBJECTIVE: To compare ultrastructural muscle tissue of myocardial bridge and the ventricular wall; to analyze the degree of injury to the tunica intima of the arterial segments, and look for possible changes that may precede or initiate the process of atherosclerotic lesions. METHODS: Forty Canchim bovine hearts were studied regarding alterations of the tunica intima from coronary arteries on the different myocardial bridge segments. For the microscopic examination, hematoxylin-eosin and fuchsin-resorcin staining following conventional microscope techniques were made. For the electronic microscopic examination, myocardial Bridge segments from twelve Canchim bovine hearts were collected from the ventricle wall and coronary artery and were processed according to conventional techniques. RESULTS: In the light microscopy, a higher frequency of lesions on prepontine and postpontine segments of the tunica intima was observed, compared to the pontine segment. Tunica intima thickenings were followed by a disarrangement on the internal elastic limitant lamina. These cells often presented their cytoplasmas engorged by lipidic drops, making up the so-called foam cells. Electronic microscopy revealed that the muscular fibers of the myocardial bridge are usually joined in a straight and smooth way presenting lateral branches with a greater number of mitochondria in the ventricular muscle than in the bridge. CONCLUSION: There are few differences between the muscle tissues studied; intimae lesions are less frequent in pontine regions compared to pre and post-pontine regions.

FUNDAMENTO: La influencia que el puente miocárdico ejerce sobre la corriente sanguínea en el transcurso del segmento arterial bajo el puente, ha sido objeto de discusión por parte de la comunidad científica. OBJECTIVO: Comparar el tejido muscular ultra estructural del puente miocárdico y la pared ventricular; analizar el grado de lesión de la capa íntima de los segmentos arteriales e investigar posibles cambios que pueden preceder o iniciar el proceso de lesiones ateroscleróticas. MÉTODO: Cuarenta corazones bovinos de la raza Canchim fueron estudiados con respecto a las alteraciones de la capa íntima de las arterias coronarias en los diferentes segmentos del puente miocárdico. Para el examen microscópico, se hicieron coloraciones por hematoxilina-eosina y fucsina-resorcina secundando las técnicas microscópicas convencionales. Para el examen de microscopía electrónica, los segmentos del puente miocárdico de doce corazones de bovinos de la raza Canchim, fueron recolectados así como de la pared ventricular y de la arteria coronaria y fueron procesados de acuerdo con las técnicas convencionales. RESULTADOS: En la microscopía de luz, observamos una mayor frecuencia de lesiones en segmentos de pre puente y pos-puente de la capa íntima, en comparación con el segmento puente. Los espesamientos de la capa íntima vinieron acompañados por un desarreglo en la lámina limitante elástica interna. Esas células a menudo presentan sus citoplasmas ingurgitados por gotas lipídicas, lo que compone las llamadas células de espuma. La microscopía electrónica reveló que las fibras musculares del puente miocárdico generalmente se unen de forma recta y lisa, presentando ramas laterales con un número mayor de mitocondrias en el músculo ventricular que en el puente. CONCLUSIONES: Existen pocas diferencias entre los tejidos musculares estudiados. Las lesiones de la capa íntima son menos frecuentes en las regiones del puente en comparación con las regiones pre y pos puente.

Origin and development of the coronary arteries / Origen y desarrollo de las arterias coronarias

The formation of the coronary vasculature is a fundamental event in heart development and involves a series of carefully regulated temporal events that include vasculogenesis and angiogenesis. This review focuses the knowledge concerning the formation of the coronary arteries available so far and some molecular mechanisms involved in this process. Understanding coronary embryogenesis is important for interventions regarding adult cardiovascular diseases as well as those necessary to correct heart congenital defects. The insight of the coronary artery development as a result of ingrowth changed the understanding of several congenital coronary artery variations and anomalies described in gross anatomy.

La formación de la vascularización coronaria es un acontecimiento fundamental en el desarrollo del corazón e implica una serie de eventos temporales cuidadosamente regulados que incluyen vasculogénesis y angiogénesis. Esta revisión se focaliza en el conocimiento sobre la formación de las arterias coronarias y algunos mecanismos moleculares implicados en este proceso. Entender la embriogénesis coronaria es importante para las intervenciones relacionadas con las enfermedades cardiovasculares en los adultos, así como también, para corregir defectos congénitos del corazón. La idea del desarrollo de la arteria coronaria, como resultado del crecimiento interno, cambió la comprensión de diversas variaciones y anomalías congénitas de estas arterias descritas en la anatomía macroscópica.

Pathomorphologic study of the fibrous cap and fatty core of coronary arthrosclerotic plaque in sudden coronary death / 法医学杂志

OBJECTIVE@#The differences in the thickness of fibrous cap and the percentage of fatty core of the coronary atherosclerotic plaques between sudden coronary death (SCD) group and the control group were investigated.@*METHODS@#Sixty-four autopsy cases were divided into SCD and control groups. Samples were taken from the most severely damaged portions of the coronary atherosclerotic plaques, sectioned, stained with HE, and the percentage of examined by light microscopy for morphologic changes and structural alternations. Image analysis system was adopted to compare the thickness of fibrous cap and percentage of fatty core in the whole plaque between the two groups, and allthe data were analyzed and calculated with SPSS 11.5 statistic software.@*RESULTS@#There were 15 grade III and 21 grade IV atherosclerotic cases found in the SCD group, while there were 16 and 12 found in the control group, respectively. Although no significant differences on the severity of atherosclerosis were found between the two groups (P > 0.05), there were significant differences on the thickness of the fibrous cap and the percentage of fatty core found between the two groups (P < 0.01).@*CONCLUSION@#Our study indicates that there are significant differences in the thickness of fibrous cap and the percentage of fatty core in atherosclerosis plaques between the SCD group and the control group. These observed differences may be helpful for morphological diagnosis of SCD.

Anatomical study of the anterior interventricular septal branches and their relationship with the blood supply of the septomarginal trabecula

The aim of this study was to examine the morphological features of the anterior interventricular septal branches that supply blood to the septomarginal trabecula and to correlate the anatomical observations with the angiographic characteristics analyzed by hemodynamic procedures. Forty human hearts were dissected after injecting colored latex into the left coronary artery. The vascularization of the septomarginal trabecula was always derived from the anterior interventricular artery, via the first, second and third anterior interventricular septal branches in 21 hearts (52.5%), 17 hearts (42.5%) and two hearts (5%), respectively, and the distances from the left coronary artery ostium ranged from 22 to 51 mm. The external diameter of these vessels at their origin varied from 1.0 to 2.35 mm and the vessels were analyzed based on specific requirements for surgical and hemodynamic methods of myocardial revascularization. Myocardial bridges were located over or before the origin of the vessels studied.

Estudo microscópico das pontes de miocárdio sobre as veias cadíacas de suínos / Microscopic study of the myocardial bridges over cardiac veins of pigs

Com o objetivo de fazer um estudo, em microscópio de luz, das pontes de miocárdio sobre as veias cardíacas, utilizaram-se 5 corações de suínos de ambos os sexos. Esses corações foram fixados em formol a 10 por cento, por um período de 10 dias, embebidos em parafina e submetidos a cortes histológicos seriados de 15µm de espessura. A seguir, os cortes foram corados pelos métodos de Azan e Weigert-van Gieson. Verificou-se que as pontes de miocárdio eram constituídas por fibras da camada superficial do miocárdio. A parede dos segmentos venosos pré-pontino pós-pontino e pontino das veias cardíacas magna e média de suínos era delgada e possuía características semelhantes. A túnica média apresentava modificações estruturais de acordo com a localizaçäo no plano subepicárdico: fibromuscular, próxima ao ápice cardíaco, e fibroelástica, no restante do trajeto. Sob o ponto de vista morfofuncional, as pontes de miocárdio podem ser consideradas como um fator coadjuvante do retorno venoso.

Ultrastructural changes of the external elastic lamina in experimental hypercholesterolemic porcine coronary arteries

The external elastic lamina (EEL) serves as a barrier for cells and macromolecules between the media and adventitia in the vascular wall. We evaluated the morphological changes and quantitative assessments of the EEL architecture in the coronary circulation of pigs fed with a high cholesterol diet. Confocal microscopy analysis of the EEL from hypercholesterolemic coronary arteries revealed an altered pattern characterized by fragmentation and disorganization of the EEL associated with an increase in the thickness. Computerized digital analysis of the images obtained by confocal scanning microscopy demonstrated that compared to normal coronary arteries, the EEL of hypercholesterolemic coronary arteries decreased in the percentage of their elastin content (30.80 +/- 1.64% vs. 47.85 +/- 1.82%, p = 0.001). The percentage of elastin content was negatively correlated with the vessel wall area (r = -0.82, p = 0.001). The immunoreactivity for matrix metalloproteinase-3 (MMP-3) increased in cholesterol-fed coronary arteries, predominantly in the neointima and adventitia. This study demonstrates that experimental hypercholesterolemia induced ultrastructural changes of the EEL in coronary circulation. The EEL may also be an atherosclerosis-prone area compared with the intima. The EEL may play an important role in the development of structural changes which characterizes the early phase of coronary atherosclerosis and vascular remodeling.

Scanning electron microscopic study of myocardial bridges over the branches of the pig coronary arteries

Realizamos el estudio en MEB de los puentes de miocardio con el objetivo de contribuir a un mejor conocimiento de estas estructuras. De 5 corazones de porcinos retiramos 5 bloques de cada corazón, conteniendo ramas de las arterias coronarias en sus segmentos prepontino, postpontino y pontino. Estos bloques fueron lavados en solución fisiológica, después fijadas en solución Karnovsky, y luego sometidas a las técnicas de rutina para MEB. En los 3 segmentos estudiados a la túnica íntima mostró un aspecto normal con células endoteliales delicadas, sin ningún espesamiento. La superficie epicárdica presentó células del tipo mesotelio, alargadas y losángicas. En el 3º segmento pontino junto con las fibras musculares, encontramos una cantidad considerable de células adiposas que forman una verdadera almohada, principalmente alrededor de la arteria. Las células musculares lisas del puente de miocardio no difiere del resto del tejido miocárdico

A microcirculação coronária na reperfusäo miocárdica. O fenômeno da näo reperfusão / Coronary microcirculation in myocardial reperfusion. The phenomenon of no-flow

Objetivo - Estudo da ultraestrutura dos capilares do coração, na reperfusão que sucede ao infarto do miocárdio. Material e Métodos - Cinco cães de ambos os sexos, pesando de 12 a 17,5 kg, anestesiados com pentobarbital, na dose de 30 mg/kg, de peso e ventilados com ar atmosférico, tiveram aberto o tórax e a artéria descendente anterior (DA) isolada, antes da emergência dos ramos septais. As pressões de aorta e átrio direito, eletrocardiograma e o fluxo coronário foram medidos para análise da relação pressão fluxo, objetivo de outro estudo. A DA foi ocluída por 90 min. após o que, procedeu-se à reperfusão por 20 min. Imediatamente, a DA foi canulada, injetou-se Nankin, o coração retirado, colocado em salina gelada, e em seguida fatiado, retirando-se fragmentos para estudo à microscopia eletrônica, na área marcada pelo nankin, desde o endocárdio até o epicárdio. Foi retirado um fragmento da região dorsal do coração, para estudo controle. As fatias do coração foram incubadas com TTC a 1%, a 37ºC, durante 10 min. Resultados - Na área infartada observaram-se alterações dos capilares, com edema da célula endotelial e desaparecimento das vesículas de pinocitose. Verificou-se a presença de "blebs", hemácias e neutrófilos no volume vascular. Os miócitos apresentavam desarranjo e ruptura dos miofilamentos, critólise e ruptura da membrana mitocondrial com intenso edema celular. No mesocárdio, próximo à área de não reperfusão, observaram-se capilares, com grau de lesão semelhante aos da área infartada. Os miócitos, entretanto, mostraram-se pouco alterados

Purpose - The study of the ultrastructural features of the coronary microvessels in postischemic reperfusion. Material and Methods - Five mongrel dogs of either sex, weighing 2 to 17 kg were studied Each dog was anesthesiated with 30 mg. of pentobarbital and ventilated with room air. A thoracotomy was done and the left descendent coronary artery was isolated. Aorta and right atria pressures, eletrocardiogram and coronary blood flow was measured. After 90 minutes of coronary occlusion and 20 minutes of reperfusion carbon black was injected into the anterior descending coronary artery to identify the area of impaired perfusion. The heart was excised and placed in a ice-cold saline. The left ventricle was curt transversely in six slices of 1 cm thickness parallel to the atrioventricular sulcus. Tissue specimens were taken from the subendocardial, mid-myocardial (in the non reperfused area) subepicardial and control layers for electron microscopic examination. Each slice was then incubated in a 1% solution of triphenyltetrazolium chloride (TTC) at 37ºC for 10 minutes. Results - The infarcted areas showed widespread tissue damage with relazed myofibrils cellular edema, swollen mitocondria with fractured cristae and nuclear changes. The vascular endothelium demonstrated severe injury with edema, cytoplasmic clearing, loss of pinocytotic vesicles, nuclear changes, formation of blebs into the vascular lumen and intravascular neutrophil. In the mid-myocardial layer, near the non reperfused vessels, a striking contrast was observed beetween the vessel and myocardium cells patterns. The usual picture was a severe vascular damage without myocyte injury

Cardiopatia isquêmica com artérias coronárias epicárdicas pérvias: os capilares do coraçäo no infarto agudo do miocárdio / Ischemie heart disease with normal epicardial coronary arteries: a study of the cardial capillaries after acute myocardial infarction

Foram estudados os capilares do coraçäo no infarto do miocárdio, através da microscopia eletrônica. Foram examinados os coraçöes de seis pacientes que vieram a falecer em conseqüência de infarto agudo do miocárdio, e que apresentavam artérias coronárias epicárdicas pérvias. Os fragmentos para exame foram retirados do contorno da área infartada, em tecido aparentemente normal. Foram estudados, também, os capilares normais de doze indivíduos sem cardiopatia isquêmica, através de fragmentos obtidos por biópsia cirúrgica, da face anterior do ventrículo esquerdo. O autor observou exprerssivas alteraçöes nos capilares que circundam a área infartada, com intenso edema da célula endotelial capilar e degeneraçäo das organelas intracelulares. No lume do capilar verificou-se empilhamento de hemácias e intensa congestäo capilar. Os a achados sugerem que as lesöes dos vasos capilares devem ter importância no agravamento da isquemia miocárdica e na recuperaçäo da área peri-infarto, embora näo pareçam representar o mecanismo causal da necrose do músculo cardíaco