Stem cell-based organ replacements—Airway and lung tissue engineering
Section snippets
Introduction: Current options for airway replacement
Considerable progress has been made in recent years within the field of tissue engineering, not least within the field of airway tissue engineering. Tissue engineering, as a branch of regenerative medicine, aims to apply the principles and methods of engineering and the life sciences toward the development of biological substitutes that can restore, maintain, or improve tissue function.1, 2 Tissue engineering, broken down into its constituent components, requires cells and scaffolds on which to
Unmet clinical need for tissue-engineered airways
There are a range of clinical disorders affecting the head and neck, including congenital, traumatic, and cancer-related causes, for which there are currently no good conventional therapeutic solutions. Current options for tissue replacement include the use of synthetic materials (alloplastic transplantation), autologous tissues, allotransplantation, or xenotransplantation, but these have significant limitations, as exemplified by previous experience in replacing airways.6
Congenital
Tissue engineering
Given the above limitations in providing functional tissue for replacement, interest has therefore turned increasingly to the field of regenerative medicine and tissue engineering.3, 4 The concept of regenerative medicine was introduced in 1999 with the aim of combining tissue engineering and cellular therapeutics.39 Tissue engineering applies the principles and methods of bioengineering, material science, cell transplantation, and life sciences in an effort to develop in vitro biological
Laryngeal tissue engineering
Although considerable progress has been made in regenerative medicine in recent years, replacement of functional, reinnervated tissues using tissue-engineered approaches remains a major challenge for generating active movement, as required for replacing partial or entire larynges that require mobile vocal cords, or an esophagus that is capable of normal peristalsis.6, 7 Thus, although replacement of airways,14, 42, 43, 44 blood vessels,50 or urogenital tissue80 using stem cell-based techniques
Bioartificial lungs
Recent progress has been made in the field of lung tissue engineering.96, 97 Bioartificial lungs derived from tissue engineering have the potential of overcoming organ shortages for patients in need of a lung transplant, without the need for lifelong immunosuppression, which, as discussed above, has associated morbidity and mortality.98 Development of bioartificial lungs through tissue engineering techniques offers the possibility of providing “off-the-shelf” products for transplantation into
Conclusions
It is currently unclear which of the different techniques emerging for tissue engineering airways is most effective. Thus, although both decellularized and synthetic (POSS-PCU) scaffolds have been utilized previously for tracheal tissue engineering,14, 44 to date, there are no studies directly comparing the two approaches. In addition, although in vitro,42 in vivo,44 and in situ77 tissue engineering approaches have been described in the literature, it is unclear which approach is best for
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