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Das Zeitfenster der Entwicklung der Angiogenese in PEG/PBT – Dermisersatzmatrices. Untersuchungen zur Porengröße, Collagenbeschichtung und Gasplasma-Behandlung
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Veröffentlicht: | 25. Juni 2008 |
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Introduction: Polyactive (Isotis, NV, NL) is a trade name for a series of block copolymers that are composed of alterning soft hydrophilic polyethylene glycol terephalate (PEGT) in combination with hard, hydrophobic polybutylene terephalate (PBT). Polyactive has been used in the field of wound healing, in particular as a biodegradable matrix as part of a cell seeded skin substitute for the treatment of deep skin defects. Data concerning angiogenesis into Polyactive scaffolds are however missing. Therefore, the aim of the presented study was: to quantitatively analyze vascularization of Polyactive scaffolds in vivo and study the influence of difference pore sizes to vascularization of these scaffolds.
Methods: The dorsal skinfold chamber in balb/c mice (n=30) was the model used to make the microvascular measurements in Polyactive scaffolds (300PEGT55PBT45; thickness 300 µm; diameter 5 mm). Different pore sizes (<75 µm; 75–212 µm; 250–300 µm) were used. Microcirculation was recorded on videotape. Measurements were performed at day 8, and repeated on 12, 16 and 20 days following transplantation. For intravital microscopy FITC-Dextran (5 mg/kg body weight) was used as plasma marker. Images were recorded on videotape for off-line computer assisted analysis using CapImage™.
Results: For the first time permanent in vivo observations of Polyactive scaffolds following implantation were made using a transparent window chamber in mice. Using intravital fluorescent microcopy the newly formed vessels in all tissues in the chamber could be assessed repeatedly. An increase of functional vessel density (FVD; mm/mm2) was measured in all groups. The 250–300 group showed higher FVD at all time points. Significant higher values were measured at day 8 (33,6±17,3 vs. 0,8±2,2/3,5±5,6) and day 12, respectively.
Discussion: The model of skinfold chamber is suitable to study vascularization into biomaterials such as Polyactive scaffolds. Implantation of Polyactive scaffolds had no influence to the microcirculation of surrounding host tissue.Scaffold of pore sizes of 250–300 µm are characterized by an increased red blood cell velocity and higher functional vessel density (at days 8 and 12) compared to both other groups. In the 250–300 µm group a trend to larger vessel diameter was observed.