Stephanie Nagel-Heyer

Relationship between physical, biochemical and biomechanical properties of tissue-engineered cartilage-carrier-constructs.

Three-dimensional cartilage-carrier-constructs were produced according to a standard protocol from chondrocytes of an adult mini-pig. Physical parameters (height and weight) correlated very well with total DNA content (r2=0.86, re. 0.94). The relation between DNA content and glycosaminoglycan content was less but still significant. No significant relationship was found between the elasticity module and the DNA content, even if the elasticity module increased slightly at higher DNA content. With respect to later implantation, selection of a construct for implantation based on the weight, which can be determined non-invasive and under sterile conditions, seems to be justifiable.

Knorpel aus dem Labor — eine Sackgasse?

ZusammenfassungKnorpeldefekte sind bei jüngeren und aktiven Patienten für erhebliche Funktionseinschränkungen am Bewegungs- und Stützorgan verantwortlich. Mechanismen für eine Spontanheilung existieren nicht. Aktuelle biologische Therapieansätze reparieren durch lokale Regeneration oder Umsetzung von Gelenkflächenstanzen mit begrenztem Erfolg. Zell- und Gewebekulturtechniken (Tissue Engineering) ermöglichen die Produktion von Gelenkflächenimplantaten aus körpereigenen Zellen, wie hier an einem Tiermodell dokumentiert. Der gesamte Prozess der Zellvermehrung und der Knorpelgewebebildung findet im Bioreaktor statt. Die Einjahresergebnisse bestätigen den Erfolg von Knorpel aus dem Labor. Ob sich das Tissue Engineering als Therapie durchsetzen wird, hängt neben dem weiteren Forschungsaufwand aber auch von gesundheitspolitischen Bedingungen ab. Würde das Verfahren trotz medizinischer Notwendigkeit am Markt nicht realisiert, werden die Kenntnisse, die bei seiner Entwicklung gewonnen wurden, die lokale In-situ-Regeneraion ermöglichen, wobei das Gelenk selber als Bioreaktor des Tissue Engineering dient, wenn hindernde Faktoren ausgeschaltet sind.AbstractCartilage defects are responsible in younger and active patients for substantial functional restrictions. Mechanisms for spontaneous healing do not exist. Current biological therapy concepts repair by local regeneration or transplantation of joint segments with limited success. Cell and tissue engineering techniques allow the production of joint surface implants from autologous cells, as documented in an animal model. The entire process of the proliferation and the cartilage tissue formation takes place in a bioreactor. The 1-year follow-up confirms the success of cartilage from the bioreactor. Whether tissue engineering will become generally accepted as therapy depends, apart from the still necessary research expenditure, on conditions of healthcare policy. If the procedure is not realized despite its medical usefulness in the market, the knowledge gained through its development will make local in situ regeneration possible, whereby the joint itself serves as a bioreactor for tissue engineering if preventing factors are eliminated.

Construction and Operation of a Bioreactor for Three-Dimensional Cartilage-Implants

A bioreactor system is essential for long term cultivation and generation of cartilage implants. Cultivation in a bioreactor system has the advantages of reduced contamination risk, better process control and easier handling. The cultivation conditions in a static culture for example in a 12-well-plate are not easily transferred to a bioreactor system, so new cultivation strategies have to be developed.