Fibronectin-derived Epiviosamines enhance PDGF-BB-stimulated human dermal fibroblast migration in vitro and granulation tissue formation in vivo.

Fibronectin (FN) is a multimodular glycoprotein that is a critical component of the extracellular matrix (ECM) anlage during embryogenesis, morphogenesis, and wound repair. Our laboratory has previously described a family of FN-derived peptides collectively called "epiviosamines" that enhance platelet-derived growth factor-BB (PDGF-BB)-driven tissue cell survival, speed burn healing, and reduce scarring. In this study, we used an agarose drop outmigration assay to report that epiviosamines can enhance PDGF-BB-stimulated adult human dermal fibroblast (AHDF) outmigration in a dose-dependent manner.

Vasoactive effect of fibronectin-derived epiviosamine-1 and related peptides in quiescent and stress models.

Objective: Following thermal burn injury, plasma fibronectin degrades within the interstitium; one possible product is EVA-1, PSHISKYILRWRPK found within the FNIII . EVA-1 ameliorates thermal burn injury progression, and binds to and enhances PDGF-BB in promoting cell metabolism, growth and survival; shorter related peptides lose these abilities. Here we study the effect of EVA-1 and shorter peptides for their vasoactivity under quiescent and stress conditions.

Blood vessel occlusion in peri-burn tissue is secondary to erythrocyte aggregation and mitigated by a fibronectin-derived peptide that limits burn injury progression.

Although vascular occlusion has long been noted in peri-burn tissue, the literature is inconsistent regarding the nature of the occlusion, with articles in the 1940s claiming that erythrocytes were the culprit and in the 1980s-1990s that microthrombi were responsible. To better define the nature of vessel occlusion, we studied two porcine burn models, a hot comb horizontal injury model and a vertical injury progression model. In both cases, tissue from the first two days after burn were stained with hemotoxylin and eosin, or probed for platelets or for fibrinogen/fibrin.

ICG angiography predicts burn scarring within 48 h of injury in a porcine vertical progression burn model.

The current standard of care in determining the need to excise and graft a burn remains with the burn surgeon, whose clinical judgment is often variable. Prior work suggests that minimally invasive perfusion technologies are useful in burn prognostication. Here we test the predictive capabilities of Laser Doppler Imaging (LDI) and indocyanine green dye (ICG) angiography in the prediction of burn scarring 28 days after injury using a previously validated porcine burn model that shows vertical progression injury.

A fibronectin peptide redirects PDGF-BB/PDGFR complexes to macropinocytosis-like internalization and augments PDGF-BB survival signals.

Growth factor-binding domains identified in various extracellular matrix proteins have been shown to regulate growth factor activity in many ways. Recently, we identified a fibronectin peptide (P12) that can bind platelet-derived growth factor BB (PDGF-BB) and promote adult human dermal fibroblast (AHDF) survival under stress. In vivo experiments in a porcine burn injury model showed that P12 limited burn injury progression, suggesting an active role in tissue survival.

Indocyanine green dye angiography accurately predicts survival in the zone of ischemia in a burn comb model.

Introduction: Surgical evaluation of burn depth is performed via clinical observation, with only moderate reliability. While perfusion analysis has been proposed to enhance accuracy, no perfusion study has attempted to predict burn extension into the area of ischemia surrounding the original insult. We examined whether laser Doppler imaging (LDI) and indocyanine green (ICG) angiography predicted survival in the zone of ischemia in a porcine hot comb burn model.

Fibronectin peptides that bind PDGF-BB enhance survival of cells and tissue under stress.

Stressors after injury from a multitude of factors can lead to cell death. We have identified four fibronectin (FN) peptides: two from the first FN type III repeat (FNIII1), one from the 13th FN type III repeat (FNIII13), and one from FN variable region (IIICS), which when tethered to a surface acted as platelet-derived growth factor-BB (PDGF-BB) enhancers to promote cell survival. One of the FNIII1 peptides and its smallest (14-mer) bioactive form (P12) were also active in solution.

High cell density attenuates reactive oxygen species: implications for in vitro assays.

In vitro cell-based assays are an essential and universally used step in elucidation of biological processes as well as in drug development. However, results obtained depend on the validity of protocols used. This statement certainly pertains to in vitro assays of oxidative stress.

Spatiotemporal progression of cell death in the zone of ischemia surrounding burns.

Burns are dynamic injuries, characterized by progressive death of surrounding tissue over time. Although central to an understanding of burn injury progression, the spatiotemporal degrees and rates of cellular necrosis and apoptosis in the zone of ischemia surrounding burns are not well characterized. Using a validated porcine hot comb model, we probed periburn tissue at 1, 4, and 24 hours after injury for high-mobility group box 1 as a marker of necrosis and activated cleaved caspase-3 as a marker of apoptosis, followed by spatiotemporal morphometric analysis.

Validation of a vertical progression porcine burn model.

A major potential goal of burn therapy is to limit progression of partial- to full-thickness burns. To better test therapies, the authors developed and validated a vertical progression porcine burn model in which partial-thickness burns treated with an occlusive dressing convert to full-thickness burns that heal with scarring and wound contraction. Forty contact burns were created on the backs and flanks of two young swine using a 150 g aluminum bar preheated to 70°C, 80°C, or 90°C for 20 or 30 seconds.

Curcumin reduces injury progression in a rat comb burn model.

The oriental spice curcumin has anti-inflammatory and antioxidant effects. When given orally before injury, curcumin reduces burn progression in a rat comb burn model. The authors hypothesized that intravenous administration of curcumin after injury would reduce burn progression and that its effects are mediated through iron chelation.

Fibronectin growth factor-binding domains are required for fibroblast survival.

Fibronectin (FN) is required for embryogenesis, morphogenesis, and wound repair, and its Arg-Gly-Asp-containing central cell-binding domain (CCBD) is essential for mesenchymal cell survival and growth. Here, we demonstrate that FN contains three growth factor-binding domains (FN-GFBDs) that bind platelet-derived growth factor-BB (PDGF-BB), a potent fibroblast survival and mitogenic factor. These sites bind PDGF-BB with dissociation constants of 10-100 nM.

Rosiglitazone, a PPAR-gamma ligand, reduces burn progression in rats.

Burns induce the activation of an inflammatory cascade that generates reactive oxygen radicals and lipid peroxidation leading to burn wound progression and extension. Peroxisome proliferation-activated receptor-gamma is a nuclear hormone receptor that is activated by transcription factors and plays an important role in the regulation of cellular proliferation and inflammation. We hypothesized that treatment of burns with rosiglitazone, a peroxisome proliferation-activated receptor-gamma ligand, would reduce burn wound progression.

Three-dimensional migration of human adult dermal fibroblasts from collagen lattices into fibrin/fibronectin gels requires syndecan-4 proteoglycan.

Fibroblast migration from the peri-wound collagenous stroma into the fibrin-laden wound is critical for granulation tissue formation and subsequent healing. Previously we found that fibroblast transmigration from a collagen matrix into a fibrin matrix required fibronectin (FN). Integrins alpha4beta1, alpha5beta1, and alphavbeta3 and dermatan sulfate CD44 were required for this invasive migration.

Fibroblast invasive migration into fibronectin/fibrin gels requires a previously uncharacterized dermatan sulfate-CD44 proteoglycan.

After tissue injury, fibroblast migration from the peri-wound collagenous stroma into the fibrin-laden wound is critical for granulation tissue formation and subsequent healing. Recently we found that fibroblast transmigration from a collagen matrix into a fibrin matrix required the presence of fibronectin. Several integrins-alpha 4 beta 1, alpha 5 beta 1, and alpha v beta 3-with known fibronectin binding affinity were necessary for this invasive migration.