Vascular endothelial growth factor and fibroblast growth factor-2 incorporation in starch-based bone tissue-engineered constructs promote the in vivo expression of neovascularization mediators.

The ideal bone tissue-engineered (TE) construct remains to be found, although daily discoveries significantly contribute to improvements in the field and certainly have valuable long-term outcomes. In this work, different TE elements, aiming at bone TE applications, were assembled and its effect on the expression of several vascularization/angiogenesis mediators analyzed. Starch/polycaprolactone (SPCL) scaffolds, obtained by two different methodologies, were combined with fibrin sealant (Baxter(®)), human adipose-derived stem cells (hASCs), and growth factors (vascular endothelial growth factor [VEGF] or fibroblast growth factor-2 [FGF-2]), and implanted in vascular endothelial growth factor receptor-2 (VEGFR2)-luc transgenic mice. The expression of VEGFR2 along the implantation of the designed constructs was followed using a luminescence device (Xenogen(®)) and after 2 weeks, the explants were retrieved to perform histological analysis and reverse transcriptase-polymerase chain reaction for vascularization (VEGF and VEGFR1) and inflammatory (tumor necrosis factor-alpha, interleukin-4, and interferon-gamma) markers. It was showed that SPCL scaffolds obtained by wet spinning and by fiber bonding constitute an adequate support for hASCs. The assembled TE constructs composed by fibrin sealant, hASCs, VEGF, and FGF-2 induce only a mild inflammatory reaction after 2 weeks of implantation. Additionally, the release of VEGF and FGF-2 from the constructs enhanced the expression of VEGFR2 and other important mediators in neovascularization (VEGF and VEGFR1). These results indicate the potential of VEGF or FGF-2 within a bone TE construct composed by wet-spun SPCL, fibrin sealant, and hASCs in promoting the vascularization of newly formed tissue.

In vivo performance of chitosan/soy-based membranes as wound-dressing devices for acute skin wounds.

Wound management represents a major clinical challenge on what concerns healing enhancement and pain control. The selection of an appropriate dressing plays an important role in both recovery and esthetic appearance of the regenerated tissue. Despite the wide range of available dressings, the progress in the wound care market relies on the increasing interest in using natural-based biomedical products. Herein, a rat wound-dressing model of partial-thickness skin wounds was used to study newly developed chitosan/soy (cht/soy)-based membranes as wound-dressing materials. Healing and repair of nondressed, cht/soy membrane-dressed, and Epigard(®)-dressed wounds were followed macroscopically and histologically for 1 and 2 weeks. cht/soy membranes performed better than the controls, promoting a faster wound repair. Re-epithelialization, observed 1 week after wounding, was followed by cornification of the outermost epidermal layer at the second week of dressing, indicating repair of the wounded tissue. The use of this rodent model, although in impaired healing conditions, may enclose some drawbacks regarding the inevitable wound contraction. Moreover, being the main purpose the evaluation of cht/soy-based membranes' performance in the absence of growth factors, the choice of a clinically relevant positive control was limited to a polymeric mesh, without any growth factor influencing skin healing/repair, Epigard. These new cht/soy membranes possess the desired features regarding healing/repair stimulation, ease of handling, and final esthetic appearance-thus, valuable properties for wound dressings.

Expression of the thrombin receptor PAR-1 correlates with tumour cell differentiation of pancreatic adenocarcinoma in vitro.

Patients with pancreatic cancer frequently suffer from thrombosis due to excess thrombin generation. Yet, the effects of thrombin on pancreatic cancer are still poorly understood. The thrombin receptor PAR-1 is responsible for cellular effects of thrombin. PAR-1 plays an important role in the progression of different solid tumours in vitro. In breast cancer the level of PAR-1 expression correlates with invasiveness. Our aim was to correlate PAR-1 mRNA and protein expression level with the grade of differentiation of pancreatic tissue and cancer cell lines. PAR-1 protein was not detectable in the epithelium of healthy pancreas. Analysis of PAR-1 protein expression by immunofluorescence staining of pancreatic cancer cell lines revealed a correlation to the grade of differentiation. Quantitative analysis of PAR-1 protein expression by Western Blot analysis confirmed these observations. Analysis of PAR-1 mRNA expression showed low levels in healthy pancreas compared to pancreatic cancer tissue and the pancreatic cancer cell line MIA PaCa-2. The level of PAR-1 mRNA differed up to 25 fold between the respective pancreatic cancer cell lines. The eminent differences in PAR-1 expression, both protein and mRNA, between healthy pancreatic tissue and pancreatic cancer in vivo and in vitro emphasise the putative role of PAR-1 in pancreatic cancer progression.