Ismar N. Cestari

Late Gadolinium Enhancement Magnetic Resonance Imaging in the Diagnosis and Prognosis of Endomyocardial Fibrosis Patients

Background— Endocardial fibrous tissue (FT) deposition is a hallmark of endomyocardial fibrosis (EMF). Echocardiography is a first-line and the standard technique for the diagnosis of this disease. Although late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) allows FT characterization, its role in the diagnosis and prognosis of EMF has not been investigated. Methods and Results— Thirty-six patients (29 women; age, 54±12 years) with EMF diagnosis after clinical evaluation and comprehensive 2-dimensional Doppler echocardiography underwent cine-CMR for assessing ventricular volumes, ejection fraction and mass, and LGE-CMR for FT characterization and quantification. Indexed FT volume (FT/body surface area) was calculated after planimetry of the 8 to 12 slices obtained in the short-axis view at end-diastole (mL/m2). Surgical resection of FT was performed in 16 patients. In all patients, areas of LGE were confined to the endocardium, frequently as a continuous streak from the inflow tract extending to the apex, where it was usually most prominent. There was a relation between increased FT/body surface area and worse New York Heart Association functional class and with increased probability of surgery (P<0.05). The histopathologic examination of resected FT showed typical features of EMF with extensive endocardial fibrous thickening, proliferation of small vessels, and scarce inflammatory infiltrate. In multivariate analysis, the patients with FT/body surface area >19 mL/m2 had an increased mortality rate, with a relative risk of 10.8. Conclusions— Our study provides evidence that LGE-CMR is useful in the diagnosis and prognosis of EMF through quantification of the typical pattern of FT deposition.

Changes in cardiac heparan sulfate proteoglycan expression and streptozotocin-induced diastolic dysfunction in rats

BackgroundChanges in the proteoglycans glypican and syndecan-4 have been reported in several pathological conditions, but little is known about their expression in the heart during diabetes. The aim of this study was to investigate in vivo heart function changes and alterations in mRNA expression and protein levels of glypican-1 and syndecan-4 in cardiac and skeletal muscles during streptozotocin (STZ)-induced diabetes.MethodsDiabetes was induced in male Wistar rats by STZ administration. The rats were assigned to one of the following groups: control (sham injection), after 24 hours, 10 days, or 30 days of STZ administration. Echocardiography was performed in the control and STZ 10-day groups. Western and Northern blots were used to quantify protein and mRNA levels in all groups. Immunohistochemistry was performed in the control and 30-day groups to correlate the observed mRNA changes to the protein expression.ResultsIn vivo cardiac functional analysis performed using echocardiography in the 10-day group showed diastolic dysfunction with alterations in the peak velocity of early (E) diastolic filling and isovolumic relaxation time (IVRT) indices. These functional alterations observed in the STZ 10-day group correlated with the concomitant increase in syndecan-4 and glypican-1 protein expression. Cardiac glypican-1 mRNA and skeletal syndecan-4 mRNA and protein levels increased in the STZ 30-day group. On the other hand, the amount of glypican in skeletal muscle was lower than that in the control group. The same results were obtained from immunohistochemistry analysis.ConclusionOur data suggest that membrane proteoglycans participate in the sequence of events triggered by diabetes and inflicted on cardiac and skeletal muscles.

A new approach to heart valve tissue engineering: mimicking the heart ventricle with a ventricular assist device in a novel bioreactor.

The ‘biomimetic’ approach to tissue engineering usually involves the use of a bioreactor mimicking physiological parameters whilst supplying nutrients to the developing tissue. Here we present a new heart valve bioreactor, having as its centrepiece a ventricular assist device (VAD), which exposes the cell–scaffold constructs to a wider array of mechanical forces. The pump of the VAD has two chambers: a blood and a pneumatic chamber, separated by an elastic membrane. Pulsatile air‐pressure is generated by a piston‐type actuator and delivered to the pneumatic chamber, ejecting the fluid in the blood chamber. Subsequently, applied vacuum to the pneumatic chamber causes the blood chamber to fill. A mechanical heart valve was placed in the VADs inflow position. The tissue engineered (TE) valve was placed in the outflow position. The VAD was coupled in series with a Windkessel compliance chamber, variable throttle and reservoir, connected by silicone tubings. The reservoir sat on an elevated platform, allowing adjustment of ventricular preload between 0 and 11 mmHg. To allow for sterile gaseous exchange between the circuit interior and exterior, a 0.2 µm filter was placed at the reservoir. Pressure and flow were registered downstream of the TE valve. The circuit was filled with culture medium and fitted in a standard 5% CO2 incubator set at 37 °C. Pressure and flow waveforms were similar to those obtained under physiological conditions for the pulmonary circulation. The ‘cardiomimetic’ approach presented here represents a new perspective to conventional biomimetic approaches in TE, with potential advantages. Copyright

Endothelial cell responses to castor oil-based polyurethane substrates functionalized by direct laser ablation

Surface-induced thrombosis and lack of endothelialization are major drawbacks that hamper the widespread application of polyurethanes for the fabrication of implantable cardiovascular devices. Endothelialization of the blood-contacting surfaces of these devices may avoid thrombus formation and may be implemented by strategies that introduce micro and submicron patterns that favor adhesion and growth of endothelial cells. In this study, we used laser radiation to directly introduce topographical patterns in the low micrometer range on castor oil-based polyurethane, which is currently employed to fabricate cardiovascular devices. We have investigated cell adhesion, proliferation, morphology and alignment in response to these topographies. Reported results show that line-like and pillar-like patterns improved adhesion and proliferation rate of cultured endothelial cells. The line-like pattern with 1 μm groove periodicity was the most efficient to enhance cell adhesion and induced marked polarization and alignment. Our study suggests the viability of using laser radiation to functionalize PU-based implants by the introduction of specific microtopography to facilitate the development of a functional endothelium on target surfaces.

Computational tool for morphological analysis of cultured neonatal rat cardiomyocytes.

This study describes the development and evaluation of a semiautomatic myocyte edge-detector using digital image processing. The algorithm was developed in Matlab 6.0 using the SDC Morphology Toolbox. Its conceptual basis is the mathematical morphology theory together with the watershed and Euclidean distance transformations. The algorithm enables the user to select cells within an image for automatic detection of their borders and calculation of their surface areas; these areas are determined by adding the pixels within each myocytes boundaries. The algorithm was applied to images of cultured ventricular myocytes from neonatal rats. The edge-detector allowed the identification and quantification of morphometric alterations in cultured isolated myocytes induced by 72 hours of exposure to a hypertrophic agent (50 μM phenylephrine). There was a significant increase in the mean surface area of the phenylephrine-treated cells compared with the control cells (p<;0.05), corresponding to cellular hypertrophy of approximately 50%. In conclusion, this edge-detector provides a rapid, repeatable and accurate measurement of cell surface areas in a standardized manner. Other possible applications include morphologic measurement of other types of cultured cells and analysis of time-related morphometric changes in adult cardiac myocytes.

Um circuito simples com bomba única para circulação extracorpórea com oxigenação autógena

It was tested in 30 dogs a circuit capable to allow extracorporeal circulation (ECC) with autogenous oxygenation (AO) of the blood employing an only centrifugal pump. With this assembly is unnecessary a pump to the right side: the gradient of transpulmonary pressure was obtained by increasing the pulmonary artery pressure by volemic expansion and decreasing the left atrial pressure by draining this camera by means of a siphon. The heart was electrically fibrillated in the beginning of the bypass and defibrillated in the end. This circuit allowed the maintenance of normal hemodynamic parameters and normal blood gases level during ECC. The operative field and the mobility of the heart were similar to those provided by conventional CEC. We concluded that the use of an only centrifugal pump simplifies ECC with AO, turning it a practical choice for the procedures of myocardial revascularization.