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Heine J.,Hannover Medical School | Heine J.,Leibniz Research Laboratory for Biotechnology and Artificial Organs LEBAO | Heine J.,University of Kiel | Schmiedl A.,Hannover Medical School | And 12 more authors.
Artificial Organs | Year: 2011

Suggesting that bioartificial vascular scaffolds cannot but tissue-engineered vessels can withstand biomechanical stress, we developed in vitro methods for preclinical biological material testings. The aim of the study was to evaluate the influence of revitalization of xenogenous scaffolds on biomechanical stability of tissue-engineered vessels. For measurement of radial distensibility, a salt-solution inflation method was used. The longitudinal tensile strength test (DIN 50145) was applied on bone-shaped specimen: tensile/tear strength (SigmaB/R), elongation at maximum yield stress/rupture (DeltaB/R), and modulus of elasticity were determined of native (NAs; n=6), decellularized (DAs; n=6), and decellularized carotid arteries reseeded with human vascular smooth muscle cells and human vascular endothelial cells (RAs; n=7). Radial distensibility of DAs was significantly lower (113%) than for NAs (135%) (P<0.001) or RAs (127%) (P=0.018). At levels of 120mmHg and more, decellularized matrices burst (120, 160 [n=2] and 200mmHg). Although RAs withstood levels up to 300mmHg, ANOVA revealed a significant difference from NA (P=0.018). Compared with native vessels (NAs), SigmaB/R values were lower in DAs (44%; 57%) (P=0.014 and P=0.002, respectively) and were significantly higher in RAs (71%; 83%) (both P< 0.001). Similarly, DeltaB/R values were much higher in DAs compared with NAs (94%; 88%) (P<0.001) and RAs (87%; 103%) (P< 0.001), but equivalent in NAs and RAs. Modulus of elasticity (2.6/1.1/3.7 to 16.6N/mm 2) of NAs, DAs, RAs was comparable (P=0.088). Using newly developed in vitro methods for small-caliber vascular graft testing, this study proved that revitalization of decellularized connective tissue scaffolds led to vascular graft stability able to withstand biomechanical stress mimicking the human circulation. This tissue engineering approach provides a sufficiently stable autologized graft. © 2011, the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc. Source


Heine J.,Hannover Medical School | Heine J.,Leibniz Research Laboratory for Biotechnology and Artificial Organs LEBAO | Heine J.,University of Kiel | Schmiedl A.,Hannover Medical School | And 12 more authors.
Tissue Engineering - Part A | Year: 2011

Objectives: Tissue-engineered arterial vessels (TEAV) offer substantial advantages in small-calibered human-bypass-grafting and vascularized scaffold applications. However, histological composition of TEAV must allow for functional properties, such as vasomotoricity. Aim of this study was to characterize human TEAVs regarding morphology and vasomotoricity. Methods: Three groups containing segments of porcine carotid artery <5 mm in diameter (native [NA, n=6], decellularized [DA, n=6], and decellularized/reseeded in a bioreactor [RA, n=7] with human vascular endothelial [hvECs] and smooth muscle cells [hvSMCs]) were examined. Light and scanning electron microscopy were applied, and hvSMCs- and hvECs-associated Vasomotoricity Test conducted in Krebs-solution was used for characterization of revitalized TEAVs. Results: Morphologic examination showed cell-free extracellular matrix in DAs. Light microscopy demonstrated intact extracellular matrix components in circle-layered formation in cross sections of DAs. RAs showed small cells migrating along the remaining medial fiber structures and flat cell layers at the luminal site, identified as hvECs and hvSMCs with lower CD-31 and α-actin signaling than controls. Scanning electron microscopy showed intact flat cell layers on luminal surfaces of RAs and dense hvSMCs at their media site. DAs showed decreasing strain after stimulation. RAs retrieved vasomotoricity compared to DAs, but showed reduced contraction and incomplete relaxation compared to NAs. Conclusions: This study shows that revitalization of DA with human vascular cells resembles NA-like morphology and can ensure vasomotoricity of TEAVs. © 2011 Mary Ann Liebert, Inc. Source


Bobylev D.O.,Hannover Medical School | Bobylev D.O.,Leibniz Research Laboratory for Biotechnology and Artificial Organs LEBAO | Cebotari S.,Hannover Medical School | Cebotari S.,Leibniz Research Laboratory for Biotechnology and Artificial Organs LEBAO | And 4 more authors.
Kardiologiya | Year: 2011

Replacement of heart valves appears to be prevailing method of surgical correction of end stage valvular heart defects. Main drawback of contemporary artificial valves is lack of growth, potential for remodeling, and inclination to degeneration. To overcome these limitations the modern science in the last decade focuses on tissue engineering of valves as an alternative to their prostheses. Basic idea of the technique is the use of decellularized xenogenic allogenic matrix or biopolymers seeded with autologous cells under special conditions created in bioreactor. This literature review is devoted to a novel direction in experimental cardiosurgery - tissue engineering of heart valves which in a unique way combines biological, engineering, and technological achievements. Source

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