Biomedical Engineering Reference
In-Depth Information
8
Decellularization, Stabilization and
Functionalization of Collagenous Tissues
Used as Cardiovascular Biomaterials
Birzabith Mendoza-Novelo
1
and Juan Valerio Cauich-Rodríguez
2
1
Universidad Politécnica de Juventino Rosas
2
Centro de Investigación Científica de Yucatán
México
1. Introduction
Cardiovascular diseases are a worldwide problem being a significant cause of morbity and
mortality every year. Patients requiring heart valve replacements include those exhibiting
degenerative valvular diseases and rheumatic fever. The pathological processes include
stenosis, fibrosis, myxoid change and calcification. The fibrosis causes a reaction to normal
haemodynamic while the myxoid change reduces tensile strength of the valve due to
replacement of dense collagenous tissue by loose tissue rich in glycosaminoglycans.
Moreover, these pathologies can be observed in normal valves or fibrotic valves (Lindop,
2007).
Fortunately, the development of cardiovascular prostheses, either synthetic or biological,
has allowed to increase life expectancy and has improved the quality of life of patient
requiring either heart valves (Flanagan & Pandit, 2003; Schoen & Levi, 1999; Vesely, 2005) or
vascular grafts (Matsagas et al., 2006; Monn & West, 2008; Schmidt & Baier, 2000). The
implant technology for cardiovascular systems made use of raw materials of different
origins. For example, metallic materials and synthetic polymers have been widely used in
mechanical valves for the replacement of diseased heart valves. However, some
complications such as alterations in the hemodynamical function and thrombus formation
have been found (Zilla et al., 2008).
Biological prostheses provide some answers to these complications, although the
bioprostheses do not fulfil their objectives satisfactorily, since they display others
complications once implanted. The complications of tissue valves include calcification,
remnant tissue immunogenicity, inflammatory degradation, mechanical damage and lack of
repair (Zilla et al., 2008). Therefore, the need for safe, economic, physiologically acceptable
and viable biomaterial has motivated the modification of collagen-rich tissues.
Collagenous tissues are alternative raw materials for the manufacture of medical devices
due to their physical and biomechanical properties. These tissues promote cell interactions,
exhibit good ion and macromolecular binding capacity in addition to their electrostatic,
hemostatical and immunological properties (Li, 2007). Since 1960s, perichardial
tissues and
the porcine heart valves are two of the most widely used biological tissues in the
construction of cardiovascular devices. The introduction of these biological biomaterials was
