ISMAR NEWTON CESTARI
Projetos de Pesquisa
Unidades Organizacionais
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina - Médico
LIM/65, Hospital das Clínicas, Faculdade de Medicina
LIM/65, Hospital das Clínicas, Faculdade de Medicina
13 resultados
Resultados de Busca
Agora exibindo 1 - 10 de 13
- Assessment of the biocompatibility of the PLLA-PLCL scaffold obtained by electrospinning(2015) OYAMA, Helena T. T.; CORTELLA, Lucas R. X.; ROSA, Isabela N. S.; FILHO, Leonardo E. R.; HUI, Wang S.; CESTARI, Ismar N.; CESTARI, Idagene A.Electrospun membranes of poly (L-Lactide) / poly (L-lactide-co-caprolactone) blend were produced and evaluated by physical and mechanical tests to use as a scaffold for cell growth. The membranes were seeded with endothelial cells (HUVEC) and after culturing time it was visualized by confocal laser scanning microscopy and scanning electron microscopy. The results indicate that the process parameters were capable of producing PLLA-PLCL membranes presenting fibers with diameters in the nanometer range. The scaffolds supported cell attachment and growth, indicating the feasibility of producing scaffolds by electrospinning technique, which could be used in tissue engineering applications. (C) 2015 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of IDMEC-IST.
- Early changes in myocyte contractility and cardiac function in streptozotocin-induced type 1 diabetes in rats(2020) MARCHINI, Gustavo S.; CESTARI, Ismar N.; SALEMI, Vera M. C.; IRIGOYEN, Maria Claudia; ARNOLD, Alexandre; KAKOI, Adelia; ROCON, Camila; AIELLO, Vera D.; CESTARI, Idagene A.Diabetes can elicit direct deleterious effects on the myocardium, independent of coronary artery disease or hypertension. These cardiac disturbances are termed diabetic cardiomyopathy showing increased risk of heart failure with or without reduced ejection fraction. Presently, there is no specific treatment for this type of cardiomyopathy and in the case of type I diabetes, it may start in early childhood independent of glycemic control. We hypothesized that alterations in isolated myocyte contractility and cardiac function are present in the early stages of experimental diabetes in rats before overt changes in myocardium structure occur. Diabetes was induced by single-dose injection of streptozotocin (STZ) in rats with data collected from control and diabetic animals 3 weeks after injection. Left ventricle myocyte contractility was measured by single-cell length variation under electrical stimulation. Cardiac function and morphology were studied by high-resolution echocardiography with pulsed-wave tissue Doppler imaging (TDI) measurements and three-lead surface electrocardiogram. Triglycerides, cholesterol and liver enzyme levels were measured from plasma samples obtained from both groups. Myocardial collagen content and perivascular fibrosis of atria and ventricle were studied by histological analysis after picrosirius red staining. Diabetes resulted in altered contractility of isolated cardiac myocytes with increased contraction and relaxation time intervals. Echocardiography showed left atrium dilation, increased end-diastolic LV and posterior wall thickness, with reduced longitudinal systolic peak velocity (S') of the septum mitral annulus at the apical four-chamber view obtained by TDI. Triglycerides, aspartate aminotransferase and alkaline phosphatase were elevated in diabetic animals. Intertitial collagen content was higher in atria of both groups and did not differ among control and diabetic animals. Perivascular intramyocardial arterioles collagen did not differ between groups. These results suggest that alterations in cardiac function are present in the early phase in this model of diabetes type 1 and occur before overt changes in myocardium structure appear as evaluated by intersticial collagen deposition and perivascular fibrosis of intramyocardial arterioles.
- Surface Topography Obtained with High Throughput Technology for hiPSC-Derived Cardiomyocyte Conditioning(2022) CORTELLA, Lucas R. X.; CESTARI, I. A.; S, M.; MAZZETTO, M.; LASAGNI, A. F.; CESTARI, Ismar N.The use of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) to replace myocardial tissue after an infarct holds great promises. However, hiPSC-CM are phenotypically immature when compared to cells in the adult heart, hampering their clinical application. We aimed to develop and test a surface structuring technique that would improve hiPSC-CM structural maturation. Laser ablation was used to fabricate a micron-pattern on polyurethane surface and evaluated cell morphology, orientation and F-actin assemblage to detect phenotypic changes in response to the microtopography. This topography positively influenced cell morphology regarding to spreading area and elongation, and hiPSC-CM orientation, improving their structural maturation. The methodology thus presented has relatively low cost and is easily scalable, making it relevant for high-throughput applications such as drug screening for the pharma industry.
- The Distensibility of the Human Vena Cava and Its Importance to In Vitro Studies of Venous Compression Syndromes: A Search for a Suitable Polymer for 3-Dimensional Printing(2023) PUECH-LEAO, Pedro; TORRES, Inez O.; SILVA, Erasmo S. da; CESTARI, Ismar N.; CESTARI, Idagene A.; ROSA, Jhenyfer M. da; NAHAS, William C.; LUCCIA, Nelson DeBackground: Venous compression syndromes are clinical conditions in which the large veins are compressed by other anatomical structures. Laboratory simulations may help us better understand the hemodynamics in venous compressions by creating situations similar to those seen in vivo. The aim of this study is to produce a model of the caval bifurcation using a polymer with distensibility similar to the human vena cava. Methods: Fragments of the inferior vena cava were collected from 13 deceased kidney donors (aged 15-37 years) and were tested for deformation (strain) when subjected to distension at 50 N/cm2. Strips of 5 different polymers-thermic polyurethane and Agilus30 with Vero Magenta (AV) (in 3 different hardnesses) and silicone-were subjected to the same biomechanical tests and compared with the vena cava. A model of the caval bifurcation was produced with 3-D printing. Results: The deformation (strain) of the vena cava wall was 0.16 & PLUSMN; 0.9 when submitted to stress close to 50 N/cm2. Silicone showed a strain higher than the standard deviation of venous fragments. The strain of AV resin 95 Shore was lower than the standard deviation of the venous fragments. AV Resins 70 and 85 Shore showed strains within the standard deviation of the venous specimen, with 70 Shore being closest to the mean venous strain. Therefore, this material was selected for modeling the caval bifurcation. The computed tomography scan image generated a computer model of the caval bifurcation and was printed in 3 dimensions. In addition, the segments of 2 adjacent vertebrae were also printed to reference the compression site. Conclusions: The 3-D printing of large veins can produce models with anatomy and biome-chanics similar to those of human veins and opens a field of investigation into the hemody-namics of venous compression syndromes. Polymers with Shore A70 appear to have biomechanical properties similar to those of the vena cava wall. The model obtained in this study can be used in several in vitro studies of May-Thurner Syndrome.
- A new approach to heart valve tissue engineering: mimicking the heart ventricle with a ventricular assist device in a novel bioreactor(2011) KAASI, Andreas; CESTARI, Idagene A.; STOLF, Noedir A. G.; LEIRNER, Adolfo A.; HASSAGER, Ole; CESTARI, Ismar N.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 VAD's 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 mu m 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% CO(2) incubator set at 37 degrees 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.
- Changes in cardiac heparan sulfate proteoglycan expression and streptozotocin-induced diastolic dysfunction in rats(2011) STRUNZ, Celia M. C.; MATSUDA, Monique; SALEMI, Vera M. C.; NOGUEIRA, Adriana; MANSUR, Antonio P.; CESTARI, Ismar N.; MARQUEZINI, Monica V.Background: Changes 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. Methods: Diabetes 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. Results: In 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. Conclusion: Our data suggest that membrane proteoglycans participate in the sequence of events triggered by diabetes and inflicted on cardiac and skeletal muscles.
- Design and Hydrodynamic Performance of a Pediatric Pulsatile Pump(2019) CESTARI, I. A.; MAZZETTO, M.; OYAMA, H. T. T.; BACHT, S.; JATENE, M. B.; CESTARI, I. N.; JATENE, F. B.We report the design and hydrodynamic performance of a pulsatile blood pump and a pneumatic driver system to treat pediatric patients in need of circulatory support while waiting for a heart transplant. The blood pump consists of a pumping chamber with 15 ml stroke volume separated by a flexible diaphragm from a pneumatic chamber. The blood chamber has two orifices fitted with rings in which tri-leaflet tissue valves are placed to control the inflow and outflow of blood. Blood contacting surfaces are heparin coated. The driving unit allows operation of two pumps to assist the left and right side of the heart, independently or simultaneously in three different modes of operation: full-to-empty, ECG synchronized and asynchronous. The flow generated by the pump increases with preload and application of auxiliary negative pressure during the filling phase reaching approximately 1,6 L/min when the pump is operating in full-to-empty mode. The results suggest the performance of the pediatric VAD designed is compatible with the needs of pediatric patients up to 15 kg body weight.
- UV Direct Laser Interference Patterning of polyurethane substrates as tool for tuning its surface wettability(2016) ESTEVAM-ALVES, Regina; GUENTHER, Denise; DANI, Sophie; ECKHARDT, Sebastian; ROCH, Teja; MENDONCA, Cleber R.; CESTARI, Ismar N.; LASAGNI, Andres F.Direct Laser Interference Patterning (DLIP) is a versatile tool for the fabrication of micro and submicropatterns on different materials. In this work, DLIP was used to produce periodic surface structures on polyurethane (PU) substrates with spatial periods ranging from 0.5 to 5.0 tim. The influence of the laser energy density on the quality and topographical characteristics of the produced micropatterns was investigated. To characterize the surface topography of the produced structures, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Confocal Microscopy (CFM) were utilized. It was found that high quality and defect free periodic line-like patterns with spatial periods down to 500 nm could be fabricated, with structure depths between 0.88 up to 1.25 pin for spatial periods larger than 2.0 pin and up to 270 nm for spatial periods between 500 nm and 1.0 tim. Measurements of the contact angle of water on the treated surface allowed to identify an anisotropic wetting behavior depending mainly on the spatial period and filling factor of the structured surfaces.
- Conditioning of hiPSC-derived cardiomyocytes using surface topography obtained with high throughput technology(2021) CORTELLA, Lucas R. X.; CESTARI, Idagene A.; LAHUERTA, Ricardo D.; ARANA, Matheus C.; SOLDERA, Marcos; RANK, Andreas; LASAGNI, Andres F.; CESTARI, Ismar N.Surface functionalization of polymers aims to introduce novel properties that favor bioactive responses. We have investigated the possibility of surface functionalization of polyethylene terephthalate (PET) sheets by the combination of laser ablation with hot embossing and the application of such techniques in the field of stem cell research. We investigated the response of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to topography in the low micrometer range. HiPSC-CMs are expected to offer new therapeutic tools for myocardial replacement or regeneration after an infarct or other causes of cardiac tissue loss. However, hiPSC-CMs are phenotypically immature compared to myocytes in the adult myocardium, hampering their clinical application. We aimed to develop and test a high-throughput technique for surface structuring that would improve hiPSC-CMs structural maturation. We used laser ablation with a ps-laser source in combination with nanoimprint lithography to fabricate large areas of homogeneous micron- to submicron line-like pattern with a spatial period of 3 mu m on the PET surface. We evaluated cell morphology, alignment, sarcomeric myofibrils assembly, and calcium transients to evaluate phenotypic changes associated with culturing hiPSC-CMs on functionalized PET. Surface functionalization through hot embossing was able to generate, at low cost, low micrometer features on the PET surface that influenced the hiPSC-CMs phenotype, suggesting improved structural and functional maturation. This technique may be relevant for high-throughput technologies that require conditioning of hiPSC-CMs and may be useful for the production of these cells for drug screening and disease modeling applications with lower costs.
conferenceObject Computational tool for morphological analysis of cultured neonatal rat cardiomyocytes(2015) LEITE, Maria Ruth C. R.; CESTARI, Idagene A.; CESTARI, Ismar N.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 myocyte's 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 mu M 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.