Papillary urothelial neoplasm of low malignant potential pathology outlines
The National Science Foundation NSF defined Tissue Engineering in as the application of the principles and methods of engineering and life sciences toward fundamental understanding of structure-function relationships in normal and pathological mammalian tissues and the development of biological substitutes to restore, maintain or improve tissue function Shalak and Fox, The two prerequisites for the successful engineering of an organ are suitable cells and a biomaterial or extra celluar matrix component.
Regenerative Medicine and Tissue Engineering - Cells and Biomaterials
A large variety of cells has been proposed for the use in tissue engineering, including pluripotent embryonic stem cells ESC with all their ethical controversies, adult stem cells found in most tissues, and committed precursor cells. While the plasticity of ESC offers the potential to grow an entire organ from a single cell source, the clear differentiation of these cells remains challenging. Currently, adult cells seem to have certain advantages regarding rapid clinical translation.
Most biomaterials used in Tissue Engineering are based on acellular matrices or polyglycolic acid. Both materials must provide tissue support until the cells produce their own extracellular matrix.
Ideally, they degrade thereafter without any toxic byproducts. Over the last years we started to understand the influence of the biomechanical environment allowing these cell-biomaterial composites to unfold their full functional potential. However, many fundamental questions regarding cells and biomaterials remain unanswered.
This book will be of interest to anyone interested in the application of Tissue Engineering. It offers a wide range of topics, including the use of stem cells and adult stem cells, their applications and the development of a tailored biomaterial, highlighting the importance of cell-biomaterial interaction. It offers insights into a Preface wide variety of cells and biomaterials, explaining the groundwork required to open the avenue to the next generation biotechnology, which is Tissue Engineering.
Finally, I would like to express my appreciation to all authors who have contributed to this book. Introduction Since the initial excitement surrounding successful clinical studies of skin tissue engineering more than 20 years ago Gallico et al.
Tissue engineering generally depends upon the use of cultured cells. Since living cells do not fall into any of the existing medical product categories, this has created a great challenge for both regulatory agencies and commercial entities.
Although various treatment strategies have been developed, the fundamental technologies and infrastructure to support their widespread adoption are still limited. In this chapter, attention was focused on fundamental technology development. Three major areas, i. The concept of tissue engineering is to regenerate target tissue by mimicking the developmental or regenerative process of that tissue.
Thus, it can be considered an ideal therapeutic option for treating various tissue defects. Tissue engineering of skin, cartilage, and bone has already been shown both feasible and effective in several clinical studies, and its efficacy has attracted significant attention from both patients and doctors. However, there are several fundamental technologies which need to be improved before widespread practical use of tissue engineering in hospitals or clinics. In this chapter, the current status of cell culture media used for clinical tissue engineering and the need for the development of safe and reliable serum-free cell culture media will be discussed with special reference papillary urothelial neoplasm of low malignant potential pathology outlines bone tissue engineering.
To regenerate the lost bone tissue, autologous bone grafting is the current gold standard, though this technique is a great burden for patients because transplantable autologous bone must be harvested from a healthy site, which causes donor site morbidity and pain. Artificial bone substitutes have been developed as alternatives to autologous renal cancer jco, though bone regeneration with them is inefficient because they lack osteo-inductive properties.
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Accordingly, tissue engineering of bone bone tissue engineering has attracted significant interest because it is considered less invasive than autologous bone grafting and more efficient than artificial bone substitutes. In fact, cell-based bone tissue engineering which utilizes cells, scaffolds, and bioactive molecules has been shown even more effective than artificial bone substitute in both basic and clinical studies.
For cell-based bone tissue engineering, various tissues derived cells are utilized since osteogenic cells can be harvested from bone marrow, periosteum, papillary urothelial neoplasm of low malignant potential pathology outlines adipose tissue, though recent studies indicate that bone marrow stromal cells BMSCs, bone marrow derived multipotent mesenchymal stromal cells, or mesenchymal stem cells are the most reliable cell source because of their superior osteogenic ability Hayashi et al.
However, it is difficult to obtain adequate numbers of transplantable BMSCs from bone marrow aspirates, as they are rare in the bone marrow less than 0. Therefore, ex vivo expansion of BMSCs is required to das papillon zeugma a sufficient number of transplantable cells. Since BMSCs require several kinds of papillary urothelial neoplasm of low malignant potential pathology outlines factors for their growth, it is standard practice to use fetal bovine serum FBSwhile autologous human serum HS and pooled allogeneic HS have papillary urothelial neoplasm of low malignant potential pathology outlines been used.
It has been suggested that FBS may not be favorable for clinical applications due to the possible risk of contamination prions, viruses, zoonosis or immunological reactions against xenogeneic serum antigens Agata et al.
Although serious secondary effects of transplanted cells that were cultured in the presence of FBS have not been reported to date, a previous clinical study that utilized BMSCs cultivated in FBS-supplemented media for the treatment of osteogenesis imperfecta showed a fold increase in antibody titer against FBS in the sera of one patient who received Human papillomavirus in news infusions Horwitz et al.
Theoretically, use of autologous HS could eliminate the risks of disease transmissions and immune reactions. In fact, over mL of peripheral blood is usually required to obtain mL of autologous HS, which is only sufficient to support the growth of BMSCs for a few passages. Therefore, collection of a sufficient amount of autologous HS is a considerable burden for anaemic patients as well as for healthy female patients with a low body weight.
Furthermore, even when a sufficient amount of autologous HS can be obtained from each patient, the constituents of individual HS could vary, which might lead to variations of cell culture outcome. Thus, it is papillary urothelial neoplasm of low malignant potential pathology outlines to develop efficient and safe serum-free culture media and eventually serum-independent cell expansion protocols for tissue engineering.
Recently, several companies have launched complete serum-free culture media that can support the growth of human mesenchymal stem cells without the addition of sera Table 1. These data indicate that currently available xeno-free, serum-free media may have papillary urothelial neoplasm of low malignant potential pathology outlines potential to replace conventional serum-based media in clinical tissue engineering, though further basic studies are required to ensure its safety and efficacy.
To develop a protocol for bone tissue engineering with serum-free media, we now papillary urothelial neoplasm of low malignant potential pathology outlines current findings regarding the character of serum-free expanded cells.
Table 1. List of currently available commercial serum-free media and the osteogenic ability of postnatal stem cells cultivated in each product Since the type of expansion medium used in primary culture may affect the viability and type of cell population generated, papillary urothelial neoplasm of low malignant potential pathology outlines is important to compare the cell populations grown in serum-free and serum-containing medium. For this purpose, Lindroos et al.
They reported that the expression profiles of examined cell surface antigens were not statistically different Lindroos et al. Our previous study investigated cell surface marker expression by human BMSCs cultured in serum-free medium.
It also showed that the expression profiles of most of the examined antigens were comparable in both serum-free and serumcontaining groups, though there were some differences in the expression of CD and CD Agata et al. Since the mean fluorescence intensity of the CD antigen was stronger in serum-free expanded BMSCs, it is possible that a larger population of CDpositive cells was papillary urothelial neoplasm of low malignant potential pathology outlines by growth in serum-free medium.
In contrast, the CDpositive fraction was more evident in cells cultured in serum-based medium and only a limited number of cells were positive for CD in the serum-free group Agata et al.