Analysis of blood and lymph vascularization patterns in tissue-engineered human dermo-epidermal skin analogs of different pigmentation

PURPOSE: Bioengineered dermo-epidermal skin analogs containing melanocytes represent a promising approach to cover large skin defects including restoration of the patient's own skin color. So far, little is known about the development of blood and lymphatic vessels in pigmented skin analogs after transplantation. In this experimental study, we analyzed the advancement and differences of host blood and lymphatic vessel ingrowth into light- and dark-pigmented human tissue-engineered skin analogs in a rat model. METHODS: Keratinocytes, melanocytes, and fibroblasts from light- and dark-pigmented skin biopsies were isolated, cultured, and expanded. For each donor, melanocytes and keratinocytes were seeded in ratios of 1:1, 1:5, and 1:10 onto fibroblast-containing collagen gels. The skin analogs were subsequently transplanted onto full-thickness wounds of immuno-incompetent rats and quantitatively analyzed for vascular and lymphatic vessel density after 8 and 15 weeks. RESULTS: The skin analogs revealed a significant difference in vascularization patterns between light- and dark-pigmented constructs after 8 weeks, with a higher amount of blood vessels in light compared to dark skin. In contrast, no obvious difference could be detected within the light- and dark-pigmented group when varying melanocyte/keratinocyte ratios were used. However, after 15 weeks, the aforementioned difference in blood vessel density between light and dark constructs could no longer be detected. Regarding lymphatic vessels, light and dark analogs showed similar vessel density after 8 and 15 weeks, while there were generally less lymphatic than blood vessels. CONCLUSION: These data suggest that, at least during early skin maturation, keratinocytes, melanocytes, and fibroblasts from different skin color types used to construct pigmented dermo-epidermal skin analogs have distinct influences on the host tissue after transplantation. We speculate that different VEGF expression patterns might be involved in this disparate revascularization pattern observed

bFGF加人工真皮と植皮術による一期再建は瘢痕の成熟と弾性の改善につながる

The efficacy of one-stage artificial dermis and skin grafting was tested in a nude rat model. Reconstruction with artificial dermis is usually a two-stage procedure with 2- to 3-week intermission. If one-stage use of artificial dermis and split-thickness skin grafting are effective, the overall burden on patients and the medical cost will markedly decrease. The graft take rate, contraction rate, tissue elasticity, histology, morphometric analysis of the dermal thickness, fibroblast counting, immunohistochemistry of α-smooth muscle actin, matrix metalloproteinase-2, CD31, and F4/80, as well as gelatin zymography, real-time reverse transcriptase polymerase chain reaction for matrix metalloproteinase-2, and electron microscopy, were investigated from day 3 to 3 months postoperatively. The graft take rate was good overall in one-stage artificial dermis and skin grafting groups up to 3 weeks, and the contraction rate was greater in the two-staged artificial dermis and skin grafting group than in the skin grafting alone or one stage of artificial dermis and skin grafting groups. Split-thickness skin grafting with artificial dermis and basic fibroblast growth factor at a concentration of 1 μg/cm2 showed significantly greater elasticity by Cutometer, and the dermal thickness was significantly thinner, fibroblast counting was significantly greater, and the α-smooth muscle actin expression level was more notable with a more mature blood supply in the dermis and more organized dermal fibrils by electron microscopy at 3 weeks. Thus, one-stage artificial dermis and split-thickness skin grafting with basic fibroblast growth factor show a high graft take rate and better tissue elasticity determined by Cutometer analysis, maturity of the dermis, and increased fibroblast number and blood supply compared to a standard two-stage reconstruction.長崎大学学位論文 学位記番号:博(医歯薬)甲第621号 学位授与年月日:平成25年9月19日Author: Rodrigo Hamuy, Naoshi Kinoshita, Hiroshi Yoshimoto, Kenji Hayashida, Seiji Houbara, Masahiro Nakashima, Keiji Suzuki, Norisato Mitsutake, Zhanna Mussazhanova, Kazuya Kashiyama, Akiyoshi Hirano, Sadanori AkitaCitation: Wound Repair and Regeneration, 21(1), pp.141-154; 2013Nagasaki University (長崎大学)課程博

Spray-assisted layer-by-layer assembly on hyaluronic acid scaffolds for skin tissue engineering

Tissue engineering approaches for the development of a single epidermal-dermal scaffold to treat full-thickness skin defects have been limited by difficulties in the fabrication of a bilayer scaffold combining the specific properties of the epidermis and the dermis. Here we present an innovative approach to developing a scaffold that holds promise for skin tissue engineering. We utilize the spray-assisted layer-by-layer assembly technique to deposit a polyelectrolyte multilayer film composed of hyaluronic acid and poly-L-lysine (the epidermal component) on a porous hyaluronic acid scaffold (the dermal component), in a rapid and controlled manner. The multilayer film promotes cell adhesion, contributing to regeneration of the epidermal barrier functions of skin. While human keratinocytes attached and proliferated on the coated porous scaffolds, they did not invade the porous dermal component, thus leaving room for seeding of relevant fibroblast cell types in this scaffold. This scaffold therefore holds promise for co-culture of different cells, which may be useful for treatment of full-thickness skin defects as well as other tissue engineering applications.Contract grant sponsor: Portuguese Foundation for Science and Technology; contract grant number: BD/39396/2007Contract grant sponsors: MIT-Portugal Program; National Science Foundation Graduate Research Fellowshi

A two-component pre-seeded dermal-epidermal scaffold

We have developed a bilayered dermal-epidermal scaffold for application in the treatment of full-thickness skin defects. The dermal component gels in situ and adapts to the lesion shape, delivering human dermal fibroblasts in a matrix of fibrin and cross-linked hyaluronic acid modified with a cell adhesion-promoting peptide. Fibroblasts were able to form a tridimensional matrix due to material features such as tailored mechanical properties, presence of protease-degradable elements and cell-binding ligands. The epidermal component is a robust membrane containing cross-linked hyaluronic acid and poly-l-lysine, on which keratinocytes were able to attach and to form a monolayer. Amine-aldehyde bonding at the interface between the two components allows the formation of a tightly bound composite scaffold. Both parts of the scaffold were designed to provide cell-type-specific cues to allow for cell proliferation and form a construct that mimics the skin environment.D.S.K. acknowledges funding from the Biotechnology Research Endowment from the Department of Anesthesiology at Boston Children's Hospital. I.P.M. acknowledges the Portuguese Foundation for Science and Technology for the grant BD/39396/2007 and the MIT-Portugal Program. D.G. acknowledges the Swiss National Science Foundation for a post-doctoral fellowship (PBGEP3-129111). B.P.T. acknowledges an NIR Ruth L. Kirschstein National Research Service Award (F32GM096546)