Fibrin- versus Plasma-Gel Scaffolds - und der Einfluss von TGF-ß und bFGF auf Myofibroblasten und die Gewebeneogenese

Aachen / Publikationsserver der RWTH Aachen University (2015) [Dissertation / PhD Thesis]

Page(s): 97 S. : Ill., graph. Darst.

Abstract

One central aspect in tissue engineering is the scaffold. Due to its properties and the direct contact to cells, it strongly influences the development of the tissue engineered construct. Especially attractive are autologous materials, like fibrin. To optimize autologous PFP- and fibrin-scaffolds this work compared the basic materials platelet free plasma (PFP), platelet poor plasma (PPP), and platelet rich plasma (PRP) as autologous materials for scaffold production. Three differently concentrated PPP and PRP-gels were used. Therefore the microstructure of gels, the mechanical strength, proliferation, ECM-development and neogenesis were analyzed. Furthermore the influence of the growth factors bFGF and TGFß on myofibroblasts/HUASMCs was investigated.In conclusion all experiments show better results for the highly concentrated plasma-gels in contrast to the PFP/fibrin-gels. In particular, it could be shown that cells cultivated in PPP- and PRP-gels proliferated, produced collagen and migration was positively influenced also without the addition of FCS. Between PPP and PRP the differences were minor, just in comparison to PFP/fibrin-gels the difference were strong. So it seems that the key element is the resuspention of the fibrinogen pellet after cryoprecipitation in plasma. The results suggest that in follow-up studies the resuspention medium should be plasma and washing steps should be avoided to obtain a better basic material for fibrin based scaffolds. Furthermore the optimization mechanical strength and the reduction of blood volume should be investigated in upcoming studies.Myofibroblasts/HUASMCS had no receptors for TGF-ß, but for bFGF. Still no effect on mechanical strength, collagen synthesis, apoptosis, proliferation and necrosis on myofibroblasten/HUASMCs could be observed due to bFGF. More likely it is to expect that bFGF negatively influences collagen synthesis. In follow-up studies different combinations of growth factors should be investigated, because it is likely that those factors influence each other. The investigation of different combinations of growth factors could lead to the right combination for the desired effects on HUASMCs.