Search

Although prosthetic heart valves have saved many lives, the search for a living substitute continues with the aid of tissue engineering. Much progress has been made so far, but the translation of this technology to clinical reality remains a challenge, especially due to the structural complexity of heart valves and the harsh environment they are in. In a joint effort, researchers from Federal University of ABC and Institute Dante Pazzanese of Cardiology have conceived a new bioresorbable scaffold for heart valve tissue engineering (HVTE), whose hydrodynamic performance was first assessed and described in this work. The scaffold was studied at the mitral position of a left heart simulator from Escola Politécnica of the University of São Paulo, under 60 bpm and with no cell seeding. In this condition, two‐dimensional particle image velocimetry was performed to investigate the flow during diastolic and systolic phases. The results indicate that the scaffold can withstand the required intraventricular pressures for a simulated normal physiologic condition in a bioreactor. Furthermore, the averaged (N = 150) velocity vector maps showed a smooth and well‐distributed flow during diastole and qualitatively demonstrated no‐significant regurgitation at systole. [ABSTRACT FROM AUTHOR]

In tissue engineering bioresorbable polymers are commonly used to mimetize a damaged tissue characteristics. In spite of that, we did not find a comparative study of the response of the same cell to dense, porous, and fibrous biomaterials. The present work aimed to study the in vitro of pure polymers [poly (ε-caprolactone) (PCL) and poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV)] and their 75:25 blend in dense, porous, and fibrous forms in Vero cells, a fibroblast cell line. The biomaterials were characterized morphologically by scanning electron microscopy (SEM). The MTT assay was used for analysis of possible cytotoxicity. Vero cells were cultured on biomaterials for 120 h and submitted to SEM, morphological and cytochemical analyses. The dyes used were crystal violet (morphology), toluidine blue at pH 4.0 (for nucleic acids and glycosaminoglycans) and 2.5 (for glycosaminoglycans only), periodic acid-Schiff reactive (for neutral sugars), xylidine ponceau at pH 2.5 (for total proteins), and picrosirius/hematoxylin (for selective collagen analysis). The biomaterials studied were not considered citocytotoxic. The cells were able to adhere to and proliferate on the substrates. The cytochemical data indicate that the cells have high functional activity, with high protein synthesis on the scaffolds but do not accumulate acid or neutral sugars. The cells on the fibrous polymers appear to be more elongated, following the shape of the fibers. Regarding the scaffold form (porous or fibrous), the in vitro data do not show great superiority of one type to the other. Then, all the polymers tested are suitable for tissue engineering. [ABSTRACT FROM AUTHOR]