scholarly journals Engineered Skin Substitute Regenerates the Skin with Hair Follicle Formation

Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 400
Author(s):  
Jinmei Wang ◽  
Xiaoxiao Wang ◽  
Jundong Xie ◽  
Bin Yao ◽  
Miaohua Mo ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Nude Mice ◽  
Dermal Fibroblasts ◽  
Skin Substitute ◽  
Epidermal Stem Cells ◽  
Skin Substitutes ◽  
Immunofluorescence Analysis ◽  
Signature Genes ◽  
Thickness Skin ◽  
Dermal Papillae

Currently, engineered skin substitutes (ESS) are unable to regenerate cutaneous appendages. Recent studies have shown that skin-derived precursors (SKPs), which are extensively available, have the potential to induce hair follicle neogenesis. Here, we demonstrate that ESS consisting of culture-expanded SKPs and epidermal stem cells (Epi-SCs) reconstitute the skin with hair follicle regeneration after grafting into nude mice. SKPs seeded in a C-GAG matrix proliferated and expressed higher levels of hair induction signature genes—such as Akp2, Sox2, CD133 and Bmp6—compared to dermal fibroblasts. Moreover, when ESS prepared by seeding a mixture of culture-expanded murine SKPs and human adult Epi-SCs into a C-GAG matrix was grafted into full-thickness skin wounds in nude mice, black hairs were generated within 3 weeks. Immunofluorescence analysis showed that the SKPs were localized to the dermal papillae of the newly-formed hair follicle. Our results indicate that SKPs can serve as the hair-inductive cells in ESS to furnish it with hair genesis potential

scholarly journals Development of a Novel Pre-Vascularized Three-Dimensional Skin Substitute Using Blood Plasma Gel

2018 ◽  
Vol 27 (10) ◽  
pp. 1535-1547 ◽  
Author(s):  
Niann-Tzyy Dai ◽  
Wen-Shyan Huang ◽  
Fang-Wei Chang ◽  
Lin-Gwei Wei ◽  
Tai-Chun Huang ◽  
...  
Keyword(s):  
Wound Healing ◽  
Human Plasma ◽  
Three Dimensional ◽  
Skin Substitute ◽  
Strength Analysis ◽  
Full Thickness ◽  
Skin Substitutes ◽  
Full Thickness Skin ◽  
Post Surgery ◽  
Thickness Skin

Skin substitutes with existing vascularization are in great demand for the repair of full-thickness skin defects. In the present study, we hypothesized that a pre-vascularized skin substitute can potentially promote wound healing. Novel three-dimensional (3D) skin substitutes were prepared by seeding a mixture of human endothelial progenitor cells (EPCs) and fibroblasts into a human plasma/calcium chloride formed gel scaffold, and seeding keratinocytes onto the surface of the plasma gel. The capacity of the EPCs to differentiate into a vascular-like tubular structure was evaluated using immunohistochemistry analysis and WST-8 assay. Experimental studies in mouse full-thickness skin wound models showed that the pre-vascularized gel scaffold significantly accelerated wound healing 7 days after surgery, and resembled normal skin structures after 14 days post-surgery. Histological analysis revealed that pre-vascularized gel scaffolds were well integrated in the host skin, resulting in the vascularization of both the epidermis and dermis in the wound area. Moreover, mechanical strength analysis demonstrated that the healed wound following the implantation of the pre-vascularized gel scaffolds exhibited good tensile strength. Taken together, this novel pre-vascularized human plasma gel scaffold has great potential in skin tissue engineering.

Comparison of Autologous Full-Thickness Gingiva and Skin Substitutes for Wound Healing

2008 ◽  
Vol 17 (10-11) ◽  
pp. 1199-1209 ◽  
Author(s):  
Abraham P. Vriens ◽  
Taco Waaijman ◽  
Henk M. Van Den Hoogenband ◽  
Edith M. De Boer ◽  
Rik J. Scheper ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Chronic Wounds ◽  
Clinical Applications ◽  
Skin Substitute ◽  
Full Thickness ◽  
Skin Substitutes ◽  
Differentiation Markers ◽  
Full Thickness Skin ◽  
Thickness Skin

Ideally tissue-engineered products should maintain the characteristics of the original tissue. For example, skin represents orthokeratinized epithelium and oral gingiva represents parakeratinized epithelium. The aim of this study was to develop an autologous full-thickness gingiva substitute suitable for clinical applications and to compare it with our autologous full-thickness skin substitute that is routinely used for healing chronic wounds. Autologous full-thickness skin and gingiva substitutes were constructed under identical culture conditions from 3-mm punch biopsies isolated from the upper leg or gingiva tissue, respectively. Both consisted of reconstructed epithelia on acellular dermis repopulated with fibroblasts. To compare the characteristics of the original and reconstructed tissue, differential morphological observations and expression of differentiation markers (keratins 6, 10, and 17 and stratum corneum precursors involucrin, loricrin, and SKALP) were determined. Skin and gingiva substitutes were transplanted onto therapy-resistant leg ulcers or tooth extraction sites in order to determine their effects on wound healing. The tissue-engineered constructs maintained many of the differential histological and immunohistochemical characteristics of the original tissues from which they were derived. The skin substitute was orthokeratinized, and the gingiva substitute was parakeratinized. Transplantation of skin (n = 19) and gingiva substitutes (n = 3) resulted in accelerated wound healing with no adverse effects. As identical culture systems were used to generate both the skin and gingiva substitutes, the differences observed in tissue (immuno)histology can be attributed to intrinsic properties of the tissues rather than to environmental factors (e.g., air or saliva). This study emphasizes the importance of closely matching donor sites with the area to be transplanted. Our results represent a large step forward in the area of clinical applications in oral tissue engineering, which have until now greatly lagged behind skin tissue engineering.

Intermediate Skin Substitutes Are Unnecessary in Small (<10% TBSA) Burns

2020 ◽  
Vol 41 (5) ◽  
pp. 926-928
Author(s):  
Alexandra Michelle Lacey ◽  
Ellen Maniago ◽  
Timothy Justin Gillenwater ◽  
Haig Yenikomshian ◽  
Warren Louis Garner
Keyword(s):  
Graft Failure ◽  
Wound Care ◽  
Graft Loss ◽  
Complete Healing ◽  
Single Stage ◽  
Skin Substitute ◽  
Split Thickness Skin Graft ◽  
Limited Data ◽  
Skin Substitutes ◽  
Thickness Skin

Abstract The use of intermediate skin substitutes between debridement and final autografting is routine for many practitioners. Materials such as xenografts and allografts have been promoted to help with wound coverage before autografting. However, there is limited data for their use in relatively small burn wounds (&lt;10% TBSA). In this study, we analyzed the outcomes of 100 consecutive patients who underwent autografting for burns &lt;10% TBSA at our American Burn Association-verified burn unit in the absence of intermediate skin substitute use. We retrospectively analyzed 100 patients who underwent split thickness skin graft autografting for burns &lt;10% TBSA between November 2017 and June 2019. No patients were treated with intermediate skin substitutes. Analysis included basic demographics, comorbidities, TBSA burned, mechanism of burn, time to grafting, if grafting was performed in a single procedure or staged, graft loss (&gt;50% graft failure), and time to complete healing (no further wound care required). Twelve patients (12%) had unpredictable graft beds, and their procedure was staged. These patients underwent surgical debridement and were dressed in antimicrobial dressing for an average of 5 days before autografting. No patients had intermediate skin substitutes between procedures. Eighty-eight patients (88%) were debrided and grafted in a single stage. In the staged group, there was a 0% rate of graft failure compared with 9.1% rate of graft failure in the primarily grafted group (P = .004). There was a similar length of stay and time to complete healing in the staged group and primarily grafted group (P = .496 and P = .571). There was a significantly shorter time from injury to first procedure between the staged group and the primarily grafted group (8.7 days and 13.5 days, P = .014). In the eight instances of graft failure, infection or inadequate debridement was the cause. Seven of these eight cases required further surgical intervention. Intermediate skin substitutes are an unnecessary step in grafting small burns. These add only complexity and cost to patient care. Many patients can be debrided and grafted in a single stage. Debridement alone with delayed grafting is a highly effective surgical method when the wound bed is not suitable for immediate grafting. The use of intermediate skin substitutes in small burns requires further investigation as this study finds low benefit for this product.

scholarly journals Collagen VII Expression Is Required in Both Keratinocytes and Fibroblasts for Anchoring Fibril Formation in Bilayer Engineered Skin Substitutes

2019 ◽  
Vol 28 (9-10) ◽  
pp. 1242-1256 ◽  
Author(s):  
Dorothy M. Supp ◽  
Jennifer M. Hahn ◽  
Kelly A. Combs ◽  
Kevin L. McFarland ◽  
Ann Schwentker ◽  
...  
Keyword(s):  
Dermal Fibroblasts ◽  
Skin Substitute ◽  
Epidermal Keratinocytes ◽  
Skin Substitutes ◽  
Normal Cells ◽  
Group 4 ◽  
Normal Keratinocytes ◽  
Collagen Vii

The blistering disease recessive dystrophic epidermolysis bullosa (RDEB) is caused by mutations in the gene encoding collagen VII (COL7), which forms anchoring fibrils that attach the epidermis to the dermis. Cutaneous gene therapy to restore COL7 expression in RDEB patient cells has been proposed, and cultured epithelial autograft containing COL7-modified keratinocytes was previously tested in clinical trials. Because COL7 in normal skin is expressed in both fibroblasts and keratinocytes, cutaneous gene therapy using a bilayer skin substitute may enable faster restoration of anchoring fibrils. Hypothetically, COL7 expression in either dermal fibroblasts or epidermal keratinocytes might be sufficient for functional anchoring fibril formation in a bilayer skin substitute. To test this, engineered skin substitutes (ESS) were prepared using four combinations of normal + RDEB cells: (1) RDEB fibroblasts + RDEB keratinocytes; (2) RDEB fibroblasts + normal keratinocytes; (3) normal fibroblasts + RDEB keratinocytes; and (4) normal fibroblasts + normal keratinocytes. ESS were incubated in vitro for 2 weeks prior to grafting to full-thickness wounds in immunodeficient mice. Biopsies were analyzed in vitro and at 1, 2, or 3 weeks after grafting. COL7 was undetectable in ESS prepared using all RDEB cells (group 1), and macroscopic blistering was observed by 2 weeks after grafting in ESS containing RDEB cells. COL7 was expressed, in vitro and in vivo, in ESS prepared using combinations of normal + RDEB cells (groups 2 and 3) or all normal cells (group 4). However, transmission electron microscopy revealed structurally normal anchoring fibrils, in vitro and by week 2 in vivo, only in ESS prepared using all normal cells (group 4). The results suggest that although COL7 protein is produced in engineered skin when cells in only one layer express the COL7 gene, formation of structurally normal anchoring fibrils appears to require expression of COL7 in both dermal fibroblasts and epidermal keratinocytes.

Roles for PDGF-A and sonic hedgehog in development of mesenchymal components of the hair follicle

Development ◽  
1999 ◽  
Vol 126 (12) ◽  
pp. 2611-2621 ◽  
Author(s):  
L. Karlsson ◽  
C. Bondjers ◽  
C. Betsholtz
Keyword(s):  
Hair Follicle ◽  
Sonic Hedgehog ◽  
Expression Patterns ◽  
Critical Role ◽  
Dermal Papilla ◽  
Mesenchymal Cells ◽  
Hair Follicles ◽  
Dermal Fibroblasts ◽  
Mutant Phenotypes ◽  
Dermal Papillae

Skin appendages, such as hair, develop as a result of complex reciprocal signaling between epithelial and mesenchymal cells. These interactions are not well understood at the molecular level. Platelet-derived growth factor-A (PDGF-A) is expressed in the developing epidermis and hair follicle epithelium, and its receptor PDGF-Ralpha is expressed in associated mesenchymal structures. Here we have characterized the skin and hair phenotypes of mice carrying a null mutation in the PDGF-A gene. Postnatal PDGF-A−/− mice developed thinner dermis, misshapen hair follicles, smaller dermal papillae, abnormal dermal sheaths and thinner hair, compared with wild-type siblings. BrdU labeling showed reduced cell proliferation in the dermis and in the dermal sheaths of PDGF-A−/− skin. PDGF-A−/− skin transplantation to nude mice led to abnormal hair formation, reproducing some of the features of the skin phenotype of PDGF-A−/− mice. Taken together, expression patterns and mutant phenotypes suggest that epidermal PDGF-A has a role in stimulating the proliferation of dermal mesenchymal cells that may contribute to the formation of dermal papillae, mesenchymal sheaths and dermal fibroblasts. Finally, we show that sonic hedgehog (shh)−/− mouse embryos have disrupted formation of dermal papillae. Such embryos fail to form pre-papilla aggregates of postmitotic PDGF-Ralpha-positive cells, suggesting that shh has a critical role in the assembly of the dermal papilla.

Needleless electrospinning of PVP/PGS fibrous scaffolds for skin tissue engineering applications

2018 ◽  
Author(s):  
Antonios Keirouz ◽  
Giuseppino Fortunato ◽  
Anthony Callanan ◽  
Norbert Radacsi
Keyword(s):  
Tissue Engineering ◽  
Tensile Modulus ◽  
Dermal Fibroblasts ◽  
Skin Tissue ◽  
Skin Substitute ◽  
Electrospinning Technique ◽  
Skin Tissue Engineering ◽  
Needleless Electrospinning ◽  
High Concentrations

Scaffolds and implants used for tissue engineering need to be adapted for their mechanical properties with respect to their environment within the human body. Therefore, a novel composite for skin tissue engineering is presented by use of blends of Poly(vinylpyrrolidone) (PVP) and Poly(glycerol sebacate) (PGS) were fabricated via the needleless electrospinning technique. The formed PGS/PVP blends were morphologically, thermochemically and mechanically characterized. The morphology of the developed fibers related to the concentration of PGS, with high concentrations of PGS merging the fibers together plasticizing the scaffold. The tensile modulus appeared to be affected by the concentration of PGS within the blends, with an apparent decrease in the elastic modulus of the electrospun mats and an exponential increase of the elongation at break. Ultraviolet (UV) crosslinking of PGS/PVP significantly decreased and stabilized the wettability of the formed fiber mats, as indicated by contact angle measurements. In vitro examination showed good viability and proliferation of human dermal fibroblasts over the period of a week. The present findings provide important insights for tuning the elastic properties of electrospun material by incorporating this unique elastomer, as a promising future candidate for skin substitute constructs.

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