Preclinical Testing of Tissue-Engineered Heart Valves Re-Endothelialized Under Simulated Physiological Conditions

Abstract

Background-The in vivo regeneration capacity of decellularized heart valve grafts is still controversial. The aim of this study was to evaluate function, morphological changes, and cellular composition of decellularized versus re-endothelialized ovine pulmonary valves (PV) after implantation into lambs for 1 or 3 months. Methods and Results-PV (nϭ21) were decellularized using detergents. Twelve PV were repopulated with autologous jugular veins endothelial cells (ECs) in a dynamic pulsatile bioreactor under simulated physiological conditions. Morphological evaluation before implantation included histological stainings (H&E, Movat-pentachrome, von-Kossa, DAPI), immunostainings (anti-perlecan, anti-eNOS, anti-procollagen-I, anti-SM-␣-actin), electron microscopy (EM), and DNA extraction. Decellularization led to cell-free scaffolds with preserved extracellular matrix (ECM) including basement membrane. Reseeded PV (nϭ5) were completely covered with ECs expressing endothelial nitric oxide synthase (eNOS) and von Willebrand factor (vWF). The function of orthotopically implanted decellularized and re-endothelialized PV (nϭ7, each) was analyzed after 1 and 3 months by echocardiography and revealed no differences in competence between both groups. A confluent EC monolayer expressing eNOS/vWF was only found in re-endothelialized PV but not in decellularized PV, whereas the valve matrices were comparable repopulated with interstitial cells expressing SM-␣-actin and procollagen-I. More thrombotic and neointima formations were observed in decellularized PV. No signs of calcification were detected in both PV types. Conclusion-In

Customized Interface Biofunctionalization of Decellularized Extracellular Matrix: Toward Enhanced Endothelialization

“…Additionally, the hydrophobic aminohexanoic acid residues present in the synthetic peptides might also contribute to improve the retention of the peptide via hydrophobic interactions with the substrates. As previously reported, dECM scaffolds are rich in collagenous proteins, 1,2,8 which contain a high abundance of hydrophobic amino acids (i.e., alanine, glycine, and proline), and could therefore favor these interactions. According to the scale of hydrophilicity described by Hopp and Woods, 46 values of hydrophilicity for RGD, REDV, and YIGSR peptides are 6.3, 7.5, and -0.8, respectively, indicating a strong hydrophobic character for YIGSR.…”

“…3 Therefore, decellularized ECM (dECM) is widely used as a platform for bioengineering of medical implants, having shown its suitability in a variety of preclinical as well as clinical models. [4][5][6][7][8] In the cardiovascular field, dECM-based approaches are particularly pursued in heart valve and vascular graft engineering. 4 Here, experimental models have already successfully been translated into the preclinical and clinical settings, with, for example, a first clinical series of decellularized allogenic valves implanted in the pulmonary as well as aortic positions showing promising mid-and long-term results.…”

Xenotransplantation Using Lyophilized Acellular Porcine Cornea with Cells Grown in vivo and Stimulated with Substance-P

“…Although decellularization is an essential process to minimize immune rejection, but transplantation of acellular lyophilized tissue alone might impede the healing process and increase the risk of infection, especially in immune-privileged tissues, such as the cornea. Efficient tissue regeneration usually needs repopulation of biologic decellularized scaffolds with interstitial cells (Lichtenberg et al, 2006). In the cornea, the role of corneal cells in optical transparency is already known.…”

Substituição valvar cardíaca em ovinos – Descrição da técnica operatória e análise dos resultados

“…(GHANTA et al, 2007;MASELLI et al, 2006;RESETAR et al, 2007) The surgical procedure of valve replacement in sheep is crucial for research of new designed valves, evaluate bio-integration of decellularized and re-endothelialized valves and the capability of acellular bioprosthetic heart valve to be more durable. (LICHTENBERG et al, 2006) To establish and evaluate the technical procedures of advanced research protocol with tissue-engineered heart valves, this study sought to describe the results of a standard pre-operative, anesthetic, transoperative and post-operative protocol and outcome of pulmonic, mitral and aortic valve replacement in sheep.…”