Novel fibrin-fibronectin matrix accelerates mice skin wound healing

Plasma fibrinogen(F1)and fibronectin(pFN)polymerize to form a fibrin clot that is both a hemostatic and provisional matrix for wound healing.About 90%of plasma F1 has a homodimeric pair ofγchains(γγF1),and 10%has a heterodimeric pair ofγand more acidicγ′chains(γγ′F1).We have synthesized a novel fibrin matrix exclusively from a 1:1(molar ratio)complex ofγγ′F1 and pFN in the presence of highly active thrombin and recombinant Factor XIII(rFXIIIa).In this matrix,the fibrin nanofibers were decorated with pFN nanoclusters(termedγγ′F1:pFN fibrin).In contrast,fibrin made from 1:1 mixture ofγγF1 and pFN formed a sporadic distribution of“pFN droplets”(termedγγF1+pFN fibrin).Theγγ′F1:pFN fibrin enhanced the adhesion of primary human umbilical vein endothelium cells(HUVECs)relative to theγγF1+FN fibrin.Three dimensional(3D)culturing showed that theγγ′F1:pFN complex fibrin matrix enhanced the proliferation of both HUVECs and primary human fibroblasts.HUVECs in the 3Dγγ′F1:pFN fibrin exhibited a starkly enhanced vascular morphogenesis while an apoptotic growth profile was observed in theγγF1+pFN fibrin.Relative toγγF1+pFN fibrin,mouse dermal wounds that were sealed byγγ′F1:pFN fibrin exhibited accelerated and enhanced healing.This study suggests that a 3D pFN presentation on a fibrin matrix promotes wound healing.

Bioengineering strategies for the treatment of peripheral arterial disease

Peripheral arterial disease(PAD)is a progressive atherosclerotic disorder characterized by narrowing and occlusion of arteries supplying the lower extremities.Approximately 200 million people worldwide are affected by PAD.The current standard of operative care is open or endovascular revascularization in which blood flow restoration is the goal.However,many patients are not appropriate candidates for these treatments and are subject to continuous ischemia of their lower limbs.Current research in the therapy of PAD involves developing modalities that induce angiogenesis,but the results of simple cell transplantation or growth factor delivery have been found to be relatively poor mainly due to difficulties in stem cell retention and survival and rapid diffusion and enzymolysis of growth factors following injection of these agents in the affected tissues.Biomaterials,including hydrogels,have the capability to protect stem cells during injection and to support cell survival.Hydrogels can also provide a sustained release of growth factors at the injection site.This review will focus on biomaterial systems currently being investigated as carriers for cell and growth factor delivery,and will also discuss biomaterials as a potential stand-alone method for the treatment of PAD.Finally,the challenges of development and use of biomaterials systems for PAD treatment will be reviewed.