Tissue Engineering: Complete Autologous Valve Conduit - A New Moulding Technique*

Abstract

Manipulations in coronary flow during reperfusion did not affect postischemic cardiac function in control or aortic constriction hearts, suggesting that depressed coronary flow during early reperfusion is not a primary cause of postischemic diastolic dysfunction in the hypertrophied myocardium.

Cell colonization in degradable 3D porous matrices

“…28 One way to overcome the heterogeneity in natural matrices uses polymers to fabricate degradable 3D porous matrices. Scaffolds generated from natural polymers such as alginates, [29][30][31] chitosan, [32][33][34][35][36][37][38] collagen, 39 GAGs and elastin, [40][41][42][43] gelatin [44][45][46] and fibrin [47][48][49] have also been used as scaffolding materials. [50][51][52] A commonly used system is collagen/GAGs; 53,54 collagen/GAG based skin equivalents are already in clinical use 41,42 and under investigation for other applications such as heart valves, vascular grafts [55][56][57][58][59][60] and vascular networks.…”

Cardiovascular Tissue Engineering Based on Fibrin-Gel-Scaffolds

“…• Fibrin gel is a naturally-occurring scaffold that can be isolated as an autologous substrate from blood of the patient in question (Heselhaus, 2011); • Starting with a cell suspension in fibrinogen solution, fibrin gel scaffolds offer immediate high cell seeding efficiency and homogenous cell distribution by gelation entrapment, with a minimal loss of cells during the seeding procedure; furthermore, there is no time-consuming cell ingrowth from the scaffold surface to the deeper parts of the scaffold (Jockenhoevel et al, 2001a); • Polymerisation as well as degradation of the fibrin gel is controllable and can be adapted to tissue development through the use of the protease inhibitors, such as aprotinin and tranexamic acid (Cholewinski et al, 2009); • Local, covalent immobilisation of different growth factors is possible, while PRP gels can be developed to enhance the content and delivery of growth factors (Wirz et al, 2011); • Production of complex 3-D structures such as heart valve conduits or vascular grafts with complex side branches is possible through the use of an injection moulding technique (Flanagan et al, 2007;Jockenhoevel et al, 2001b); • Textile-reinforced fibrin-based grafts can be implanted in the arterial circulation and function for at least 6 months in vivo (Koch et al, 2010); • Fibrin-based tissue engineering can be merged with self-expanding stents to create a platform technology for cardiovascular, and other, diseases. These properties highlight the significant potential for creation of functional, autologous implantable cardiovascular prostheses in future using tissues derived from the patient.…”

“…The principles of fibrin-based cardiovascular tissue engineering can be demonstrated using the example of a completely autologous heart valve prosthesis as shown in Figure 6 (Jockenhoevel et al, 2001b). For paediatric application, the umbilical cord is the optimal cell source.…”

Tissue-Engineered Fibrin-Based Heart Valve with a Tubular Leaflet Design

“…7,8 Various approaches to create viable semilunar heart valves with remodelling capabilities have been developed by means of tissue engineering (TE). 9,10 The general approach is to mimic the shape of the native valve to recreate the natural haemodynamics 11 either by replicating the whole valvular apparatus, including the vascular part (wall) [12][13][14][15] or by reproducing only the cusps to be sutured to the native wall. [16][17][18][19] Both approaches have important limitations.…”

“…This natural polymer offers a broad range of advantageous properties, including its autologous origin, the rapid polymerization, the tuneable degradation via protease inhibitors and the manufacturability into 3D geometries. 12,32 Two different approaches were developed to realize the tube-in-tube, mainly differing in the way the construct is conditioned. In the first approach, the tubular structure is moulded and before the dynamic conditioning it is sutured into a silicon tube representing the aortic wall, including the sinuses of Valsalva.…”