Mesenchymal stem cells and myoblast differentiation under HGF and IGF-1 stimulation for 3D skeletal muscle tissue engineering

Background Volumetric muscle loss caused by trauma or after tumour surgery exceeds the natural regeneration capacity of skeletal muscle. Hence, the future goal of tissue engineering (TE) is the replacement and repair of lost muscle tissue by newly generating skeletal muscle combining different cell sources, such as myoblasts and mesenchymal stem cells (MSCs), within a three-dimensional matrix. Latest research showed that seeding skeletal muscle cells on aligned constructs enhance the formation of myotubes as well as cell alignment and may provide a further step towards the clinical application of engineered skeletal muscle. In this study the myogenic differentiation potential of MSCs upon co-cultivation with myoblasts and under stimulation with hepatocyte growth factor (HGF) and insulin-like growth factor-1 (IGF-1) was evaluated. We further analysed the behaviour of MSC-myoblast co-cultures in different 3D matrices. Results Primary rat myoblasts and rat MSCs were mono- and co-cultivated for 2, 7 or 14 days. The effect of different concentrations of HGF and IGF-1 alone, as well as in combination, on myogenic differentiation was analysed using microscopy, multicolour flow cytometry and real-time PCR. Furthermore, the influence of different three-dimensional culture models, such as fibrin, fibrin-collagen-I gels and parallel aligned electrospun poly-ε-caprolacton collagen-I nanofibers, on myogenic differentiation was analysed. MSCs could be successfully differentiated into the myogenic lineage both in mono- and in co-cultures independent of HGF and IGF-1 stimulation by expressing desmin, myocyte enhancer factor 2, myosin heavy chain 2 and alpha-sarcomeric actinin. An increased expression of different myogenic key markers could be observed under HGF and IGF-1 stimulation. Even though, stimulation with HGF/IGF-1 does not seem essential for sufficient myogenic differentiation. Three-dimensional cultivation in fibrin-collagen-I gels induced higher levels of myogenic differentiation compared with two-dimensional experiments. Cultivation on poly-ε-caprolacton-collagen-I nanofibers induced parallel alignment of cells and positive expression of desmin. Conclusions In this study, we were able to myogenically differentiate MSC upon mono- and co-cultivation with myoblasts. The addition of HGF/IGF-1 might not be essential for achieving successful myogenic differentiation. Furthermore, with the development of a biocompatible nanofiber scaffold we established the basis for further experiments aiming at the generation of functional muscle tissue

50 years experience with Dupuytren's contracture in the Erlangen University Hospital – A retrospective analysis of 2919 operated hands from 1956 to 2006

<p>Abstract</p> <p>Background</p> <p>Dupuytren's disease (DD) is a hand disorder mainly among the northern population. In contrast it is rare in the mediterranean population. Therefore typical habits and dietetic influences have been discussed as well as genetic predisposition. Still, since the first description by Dupuytren in 1834 only little is known about the etiology and pathogenesis of this disease. Some hints were found for a higher prevalence among people with diabetes, alcohol abuse or smoking. Also, intensive manual work or hand injuries have been discussed to have an influence on DD. To our knowledge this is the largest retrospectively evaluated series of symptomatic patients published to date. The study includes patients from the last 50 years. It was performed to show possible correlations between DD and typical risk factors such as diabetes, alcohol consumption, and smoking.</p> <p>Methods</p> <p>We retrospectively analysed all patient records with DD documented between 1956 and 2006 in the Surgical University Hospital in Erlangen. Data acquisition was conducted by reviewing the medical records from 1956 to 2006 including data from all patients who were surgically treated because of DD.</p> <p>Results</p> <p>We reviewed 2579 male and 340 female surgically treated patients with DD. More than 80% of the patients were between 40 and 70 years old. In 28.9% only the right hand was effected by DD, in 25.3% only the left hand and in 45.8% both hands. In 10.3% of all Patients suffered from Diabetes mellitus. Statistical analysis revealed no significant correlation between diabetes, alcoholism or smoking on the degree of DD in our patients.</p> <p>Conclusion</p> <p>Most data are consistent with previously published results from smaller, comparable retrospective studies with regard to right- or left handedness. We could not confirm a statistically significant correlation of DD with diabetes mellitus, severe alcohol consumption, heavy smoking or epilepsy and the stage of the disease as described in other studies. However, in the whole cohort of our operated patients during the last 50 years the prevalence of the above mentioned risk factors is slightly higher than in the normal population.</p

Optimierung der Vaskularisation von axial durchbluteten Matrizes im Tissue Engineering

Nowadays, autologous tissue transplantation represents the gold standard for the reconstruction of large tissue defects. To minimize the resulting donor side morbidity and to overcome the limitations regarding shape and volume of bone grafts research has focused on tissue engineering of axially vascularised tissue constructs. We have evaluated different strategies to improve the vascularisation of bioartificial transplantable tissue volumes. First we used angiogenic growth factors such as VEGF and bFGF in the subcutaneous and arteriovenous loop model in the rat to increase vessel ingrowth. Afterwards we combined the intrinsic vascular pathway of the arteriovenous loop model with an additional extrinsic vessel ingrowth by using a porous titanium chamber. Transplanted cells also showed an increased survival in the AV loop model compared to subcutaneously implanted matrices. In this manuscript we show the evolution of different newly developed methods to improve vascularisation of axially vascularised matrices in tissue engineering.Für die Therapie angeborener und erworbener Gewebedefekte, z.B. im Bereich des Knochens, stellt heutzutage nach wie vor der autologe Gewebetransfer den Goldstandard dar. Um den hierbei resultierenden Hebedefekt und die Einschränkung hinsichtlich Formbarkeit und Länge/Volumen des verfügbaren Gewebes zu minimieren, steht das Tissue Engineering von axial vaskularisierten Gewebekonstrukten im Fokus des wissenschaftlichen Interesses. Wir untersuchten verschiedene Forschungsansätze, um die Vaskularisation von bioartifiziellen, transplantierbaren Gewebekonstrukten zu verbessern. Es wurden eine Steigerung der Vaskularisation mit Hilfe verschiedener angiogenetischer Wachstumsfaktoren im Subkutanmodell und in einem arteriovenösen Gefäßschleifenmodell in der Ratte gezeigt sowie eine Kombination der arteriovenösen Gefäßschleife mit peripher einsprießenden Gefäßen mit Hilfe einer neuartigen porösen Titankammer nachgewiesen. Mit Hilfe der Gefäßschleife konnte zudem ein erhöhtes Überleben von transplantierten Zellen im Vergleich zu nicht vaskularisierten Matrizes gezeigt werden. Die hier vorgestellte Arbeit zeigt die Entwicklung neuartiger Ansätze zur Optimierung der Vaskularisation von axial durchbluteten Matrizes im Tissue Engineering

Gibt es einen Paradigmenwechsel in der rekonstruktiven Brustchirurgie?

In the present article the question of an increase in implant based breast reconstruction, as recently reported for the United States of America, is analyzed and the pertinent literature concerning a putative shift of paradigms in implant versus autologous breast reconstruction is discussed.Im vorliegenden Artikel wird die Frage einer möglichen Zunahme an Prothesen-basierter Brustrekonstruktion, wie sie kürzlich für die USA beschrieben wurde, analysiert und die aktuelle Literatur bzgl. eines postulierten Paradigmenwechsels in der Prothesen- versus Eigengewebsrekonstruktion der weiblichen Brust diskutiert