组织科学与工程学报

Although it is now known as a common term for almost two decades, ‘Tissue Engineering’ (TE) still can be considered to be a comparatively young field of basic and applied multidisciplinary biomedical research. It utilizes the principles and methods of engineering and life sciences combined with clinical expertise toward the development of biological tissue substitutes to restore, maintain or improve the function of diseased or damaged human tissues is currently leaving its eggshells behind. Without doubt the collaboration of scientists from many various disciplines has led to the development of a multitude of brilliant inventions, latest research tools and scientific techniques which are now constantly incorporated in this yet growing scientific field.

Tissue engineering the development of functional substitute to replace missing or malfunctioning human tissue and organs by using biodegradable biomaterials as scaffolds to direct specific cell types to organize into three dimensional structures and perform differentiated function of targeted tissue. The important factors to be considered in designing of microstructure were porosity, pore size, and pore structure with respect to nutrient supply for transplanted and regenerated cells. Performance of various functions of the tissue structure depends on porous scaffold microstructures with specific porosity, pore size, characteristics that influence the behavior of the incorporated cells. Finite element Methods (FEM) and Computer Aided Design (CAD) combines with manufacturing technologies such as Solid Freeform Fabrication (SFF) helpful to allow virtual design, characterization and production of porous scaffold optimized for tissue replacement with appropriate pore size. Finite Element Modeling used to calculate the stress areas in a complex scaffold structures and thus predict their mechanical behavior during in vivo environment (eg. As load bearing in bone tissue scaffolds) is evaluated. This article reviews recent development and application of Finite Element Methods (FEM) and Computer Aided Design and computer-aided manufacturing (CAD & CAM), and rapid prototyping (RP) technology in the development of porous tissue scaffolds.

Adult mesenchymal stromal cells (MSC), also referred to as mesenchymal stem cells, were detected almost half a century ago in bone marrow and have been studied intensively in the last decade. Different aspects of MSC biology were explored and published. Studies pointed to their localization in different organs during development and in adulthood and described their characteristics in experimental or clinical investigations. Despite intensive research in the field and in sharp contrast to hematopoietic stem cells (HSC), it has become more and more clear that MSC lack a unique cell surface marker. MSC not only share cell surface markers with other types of cells, they also share many features with pericytes and fibroblasts, including their capability to differentiate into, for instance, osteoblasts or adipocytes. In this review we therefore screen the current literature to disclose differences between MSC and fibroblasts and also report on common qualities.

Patients with bilateral and severe neurosensorial hypoacusia are candidates for cochlear implantation. Eventhough it’s a relatively modern procedure, it has a very low rate of complications (5-10%), making it a safe surgery. The Cohen classification is currently used to measure and group the complications of this surgery, classifying them according to the moment in which they appear whether it’s intraoperative or postoperative time. We present the case of a female patient who suffered the extrusion of the implant several months after the procedure. She was re-operated successfully, but she returned months later with a second extrusion of the same implant. We did not find any other report of this phenomenon in the revised literature. We present this case with pictures of the repair surgery and the patient’s current condition. We also analyze possible causes of this cochlear implant rejection, citing both magnetomechanical and immunomediated factors.

To improve the health and quality of life of patients suffering from neural degeneration diseases or brain and spinal cord injuries, much research has been dedicated to the repairing and regeneration of neural tissues. Although allogenic grafts have no supply limitation, they often cause undesirable immune responses. Thus, autologous grafts are usually used to treat neural defects. However, the short life of nerves and a mismatch of nerve cable dimension between the donor graft and the receptor nerve limit its clinical applications. Nerve tissue engineering has emerged as a highly promising alternative strategy to neural therapy, aimed at rebuilding the lesioned circuits of the central and peripheral nervous systems, while minimizing body’s immune responses with engineered nerves.