Wound healing is a process regulated by a complex interaction of multiple growth factors including fibroblast growth factor 2 (FGF2). Although FGF2 appears in several tissue engineered studies, its applications are limited due to its low stability both in vitro and in vivo. Here, this shortcoming is overcome by a unique nine-point mutant of the low molecular weight isoform FGF2 retaining full biological activity even after twenty days at 37 °C. Crosslinked freeze-dried 3D porous collagen/chitosan scaffolds enriched with this hyper stable recombinant human protein named FGF2-STAB® were tested for in vitro biocompatibility and cytotoxicity using murine 3T3-A31 fibroblasts, for angiogenic potential using an ex ovo chick chorioallantoic membrane assay and for wound healing in vivo with 3-month old white New Zealand rabbits. Metabolic activity assays indicated the positive effect of FGF2-STAB® already at very low concentrations (0.01 µg/mL). The angiogenic properties examined ex ovo showed enhanced vascularization of the tested scaffolds. Histological evaluation and gene expression analysis by RT-qPCR proved newly formed granulation tissue at the place of a previous skin defect without significant inflammation infiltration in vivo. This work highlights the safety and biocompatibility of newly developed crosslinked collagen/chitosan scaffolds involving FGF2-STAB® protein. Moreover, these sponges could be used as scaffolds for growing cells for dermis replacement, where neovascularization is a crucial parameter for successful skin regeneration.

Treatment of complete loss of skin thickness requires expensive cellular materials and limited skin grafts used as temporary coverage. This paper presents an acellular bilayer scaffold modified with polydopamine (PDA), which is designed to mimic a missing dermis and a basement membrane (BM). The alternate dermis is made from freeze-dried collagen and chitosan (Coll/Chit) or collagen and a calcium salt of oxidized cellulose (Coll/CaOC). Alternate BM is made from electrospun gelatin (Gel), polycaprolactone (PCL), and CaOC. Morphological and mechanical analyzes have shown that PDA significantly improved the elasticity and strength of collagen microfibrils, which favorably affected swelling capacity and porosity. PDA significantly supported and maintained metabolic activity, proliferation, and viability of the murine fibroblast cell lines. The in vivo experiment carried out in a domestic Large white pig model resulted in the expression of pro-inflammatory cytokines in the first 1–2 weeks, giving the idea that PDA and/or CaOC trigger the early stages of inflammation. Otherwise, in later stages, PDA caused a reduction in inflammation with the expression of the anti-inflammatory molecule IL10 and the transforming growth factor β (TGFβ1), which could support the formation of fibroblasts. Similarities in treatment with native porcine skin suggested that the bilayer can be used as an implant for full-thickness skin wounds and thus eliminate the use of skin grafts.

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Background: Previous surgical procedures in the abdomen are no longer contra-indications for free flap breast reconstruction using the deep inferior epigastric artery perforator flap. Nonetheless, a possible consequence of previous surgical procedures may be trauma to the deep inferior epigastric (DIE) pedicle, leading to interruption. In these cases, a modification in operative strategy may be required. Methods: A study was performed across two centers, during a 10-year period between January 1, 2010 and December 2019. Patient and outcome data were collected from the patient file and operation notes. Results: Four cases with clear evidence of DIE pedicle interruption were found, with an average age of 54 years and an average body mass index of 28.9. Three patients had a preoperative diagnosis of DIE pedicle interruption on CT angiography, whereas in one case this was found peroperatively. For three cases, unilateral reconstruction was performed, and for one, bilateral reconstruction. Four flaps (in three cases) were unipedicled; the contralateral DIE pedicle was used in three, and the superficial system was used in one. For the bipedicled case, two hemiflaps were used, with the interrupted DIE pedicle anastomosed to a branch of the contralateral DIE pedicle. Conclusions: Interrupted DIE vessels remain a challenge for free flap breast reconstruction. The four cases demonstrated in this article highlight different surgical strategies, with an emphasis on detailed preoperative planning, including CT angiography. We present an algorithm to aid the reader in approaching cases with an interrupted DIE pedicle.

Infectious complications play important role in morbidity and mortality in patients with burns. One of the most promising options, how we can manage the increasing resistance of pathogens, is the application of antibacterial enzymes called "enzybiotics". MATERIALS AND METHODS:The activity of lysostaphin was determined by the plate lysis assay and the turbidity assay. In the plate lysis assay, the bacterial suspension (108 CFU/mL) was plated on the blood agar, left to dry for 10 minutes and then lysostaphin was applied.

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