scholarly journals UV-independent induction of beta defensin 3 in neonatal human skin explants

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 288 ◽  
Author(s):  
Erin Wolf Horrell ◽  
John D'Orazio
Keyword(s):  
Human Skin ◽  
Uv Radiation ◽  
Time Course ◽  
Ex Vivo ◽  
Culture Conditions ◽  
Skin Sample ◽  
Independent Manner ◽  
Standard Culture ◽  
Skin Explants ◽  
Multiple Donors

In order to determine the effect of UV radiation on β-defensin 3 (BD3) expression in human skin, freshly-isolated UV-naïve skin was obtained from newborn male infants undergoing planned circumcision.  Skin explants sustained ex vivo dermis side down on RPMI media were exposed to 0.5 kJ/m2 UVB, and biopsies were taken from the explant through 72 hours after radiation.  mRNA expression was measured by qRTPCR and normalized to TATA-binding protein.  BD3 expression at each time point was compared with an untreated control taken at time 0 within each skin sample.  Extensive variability in both the timing and magnitude of BD3 induction across individuals was noted and was not predicted by skin pigment phenotype, suggesting that BD3 induction was not influenced by epidermal melanization.  However, a mock-irradiated time course demonstrated UV-independent BD3 mRNA increases across multiple donors which was not further augmented by treatment with UV radiation, suggesting that factors other than UV damage promoted increased BD3 expression in the skin explants.  We conclude that BD3 expression is induced in a UV-independent manner in human skin explants processed and maintained in standard culture conditions, and that neonatal skin explants are an inappropriate model with which to study the effects of UV on BD3 induction in whole human skin.

scholarly journals UV-independent induction of beta defensin 3 in neonatal human skin explants

F1000Research ◽  
2015 ◽  
Vol 3 ◽  
pp. 288 ◽  
Author(s):  
Erin Wolf Horrell ◽  
John D'Orazio
Keyword(s):  
Human Skin ◽  
Uv Radiation ◽  
Time Course ◽  
Ex Vivo ◽  
Culture Conditions ◽  
Skin Sample ◽  
Independent Manner ◽  
Standard Culture ◽  
Skin Explants ◽  
Multiple Donors

In order to determine the effect of UV radiation on β-defensin 3 (BD3) expression in human skin, freshly-isolated UV-naïve skin was obtained from newborn male infants undergoing planned circumcision.  Skin explants sustained ex vivo dermis side down on RPMI media were exposed to 0.5 kJ/m2 UVB, and biopsies were taken from the explant through 72 hours after radiation.  mRNA expression was measured by qRTPCR and normalized to TATA-binding protein.  BD3 expression at each time point was compared with an untreated control taken at time 0 within each skin sample.  Extensive variability in both the timing and magnitude of BD3 induction across individuals was noted and was not predicted by skin pigment phenotype, suggesting that BD3 induction was not influenced by epidermal melanization.  However, a mock-irradiated time course demonstrated UV-independent BD3 mRNA increases across multiple donors which was not further augmented by treatment with UV radiation, suggesting that factors other than UV damage promoted increased BD3 expression in the skin explants.  We conclude that BD3 expression is induced in a UV-independent manner in human skin explants processed and maintained in standard culture conditions, and that neonatal skin explants are an inappropriate model with which to study the effects of UV on BD3 induction in whole human skin.

Cutaneous DNA delivery and gene expression in ex vivo human skin explants via wet-etch microfabricated microneedles

2005 ◽  
Vol 13 (7) ◽  
pp. 415-421 ◽  
Author(s):  
James Birchall ◽  
Sion Coulman ◽  
Marc Pearton ◽  
Chris Allender ◽  
Keith Brain ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Skin ◽  
Ex Vivo ◽  
Dna Delivery ◽  
Skin Explants ◽  
Wet Etch

scholarly journals A vascularized 3D model of the human pancreatic islet for ex vivo study of immune cell-islet interaction

2021 ◽  
Author(s):  
R. Hugh F. Bender ◽  
Benjamen T O'Donnell ◽  
Bhupinder Shergill ◽  
Brittany Q Pham ◽  
Damie J Juat ◽  
...  
Keyword(s):  
Immune Cell ◽  
Ex Vivo ◽  
Cell Damage ◽  
Three Dimensional ◽  
Human Islets ◽  
Culture Conditions ◽  
Β Cells ◽  
Standard Culture ◽  
Key Steps

Insulin is an essential regulator of blood glucose homeostasis that is produced exclusively by β cells within the pancreatic islets of healthy individuals. In those affected by diabetes, immune inflammation, damage, and destruction of islet β cells leads to insulin deficiency and hyperglycemia. Current efforts to understand the mechanisms underlying β cell damage in diabetes rely on in vitro-cultured cadaveric islets. However, isolation of these islets involves removal of crucial matrix and vasculature that supports islets in the intact pancreas. Unsurprisingly, these islets demonstrate reduced functionality over time in standard culture conditions, thereby limiting their value for understanding native islet biology. Leveraging a novel, vascularized micro-organ (VMO) approach, we have recapitulated elements of the native pancreas by incorporating isolated human islets within a three-dimensional matrix nourished by living, perfusable blood vessels. Importantly, these islets show long-term viability and maintain robust glucose-stimulated insulin responses. Furthermore, vessel-mediated delivery of immune cells to these tissues provides a model to assess islet-immune cell interactions and subsequent islet killing -- key steps in type 1 diabetes pathogenesis. Together, these results establish the islet-VMO as a novel, ex vivo platform for studying human islet biology in both health and disease.

scholarly journals Characterization of a Topically Testable Model of Burn Injury on Human Skin Explants

2020 ◽  
Vol 21 (18) ◽  
pp. 6956
Author(s):  
Olivia Gross-Amat ◽  
Marine Guillen ◽  
Damien Salmon ◽  
Serge Nataf ◽  
Céline Auxenfans
Keyword(s):  
Human Skin ◽  
Burn Injury ◽  
Ex Vivo ◽  
Drug Formulation ◽  
Burn Injuries ◽  
Major Health Problem ◽  
Constant Tension ◽  
Skin Explants ◽  
Set Up ◽  
Improved Model

Severe burn injuries remain a major health problem due to high rates of mortality, residual morbidity, and/or aesthetic damages. To find new therapies aimed at promoting a harmonious healing of skin burns, it is important to develop models which take into account the unique properties of the human skin. Based on previously described models of burn injury performed on human skin explants, we hypothesized that maintaining explants under constant tension forces would allow to more closely reproduce the pathophysiological processes of skin remodeling. We thus. Here, we set up and characterized an improved model of deep second-degree burn injury on ex vivo cultured human skin explants at air-liquid interface and maintained under conditions of constant tension forces. A spontaneous re-epithelialization of the lesion was observed 8 to 9 days post burn and was found to rely on the proliferation of basal keratinocytes at the wound edges. Collagen VII at the dermo-epidermal junction reformed along with the progression of re-epithelializatio and a synthesis of procollagen III was observed in the dermis at the wound site. These findings indicate that our model is suitable for the assessment of clinically-relevant therapies aimed at modulating the kinetics of re-epithelialization and/or the activation of fibroblasts following skin burn injuries. In this regard, we evaluated the use of a thermoreversible poloxamer hydrogel as a vehicle for topically-testable therapeutic molecules. Our data showed that, although useful for drug formulation, the p407/p188 poloxamer hydrogel induces a delay of skin re-epithelialization in humans skin explants submitted to experimental burn injury.

scholarly journals Active neutrophil responses counteract Candida albicans burn wound infection of ex vivo human skin explants

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Christin von Müller ◽  
Fionnuala Bulman ◽  
Lysett Wagner ◽  
Daniel Rosenberger ◽  
Alessandra Marolda ◽  
...  
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Burn Wound ◽  
Local Immunity ◽  
Fungal Virulence ◽  
Opportunistic Fungi ◽  
Burn Wounds ◽  
Wound Model ◽  
Skin Explants ◽  
Bacteria And Fungi

AbstractBurn wounds are highly susceptible sites for colonization and infection by bacteria and fungi. Large wound surface, impaired local immunity, and broad-spectrum antibiotic therapy support growth of opportunistic fungi such as Candida albicans, which may lead to invasive candidiasis. Currently, it remains unknown whether depressed host defenses or fungal virulence drive the progression of burn wound candidiasis. Here we established an ex vivo burn wound model, where wounds were inflicted by applying preheated soldering iron to human skin explants, resulting in highly reproducible deep second-degree burn wounds. Eschar removal by debridement allowed for deeper C. albicans penetration into the burned tissue associated with prominent filamentation. Active migration of resident tissue neutrophils towards the damaged tissue and release of pro-inflammatory cytokine IL-1β accompanied the burn. The neutrophil recruitment was further increased upon supplementation of the model with fresh immune cells. Wound area and depth decreased over time, indicating healing of the damaged tissue. Importantly, prominent neutrophil presence at the infected site correlated to the limited penetration of C. albicans into the burned tissue. Altogether, we established a reproducible burn wound model of candidiasis using ex vivo human skin explants, where immune responses actively control the progression of infection and promote tissue healing.

The Ex Vivo Skin Model as an Alternative Tool for the Efficacy and Safety Evaluation of Topical Products

2020 ◽  
Vol 48 (1) ◽  
pp. 10-22 ◽  
Author(s):  
Samara Eberlin ◽  
Michelle Sabrina da Silva ◽  
Gustavo Facchini ◽  
Gustavo Henrique da Silva ◽  
Ana Lúcia Tabarini Alves Pinheiro ◽  
...  
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Safety Evaluation ◽  
Test System ◽  
Dermal Matrix ◽  
Standard Size ◽  
Skin Explants ◽  
Alternative Approaches ◽  
Air Liquid Interface

The development of alternative approaches for safety and efficacy testing that avoid the use of animals is a worldwide trend, which relies on the improvement of current models and tools so that they better reproduce human biology. Human skin from elective plastic surgery is a promising experimental model to test the effects of topically applied products. As the structure of native skin is maintained, including cell population (keratinocytes, melanocytes, Langerhans cells and fibroblasts) and dermal matrix (containing collagen, elastin, glycosaminoglycans, etc.), it most closely matches the effects of substances on in vivo human skin. In this review, we present a collection of results that our group has generated over the last years, involving the use of human skin and scalp explants, demonstrating the feasibility of this model. The development of a test system with ex vivo skin explants, of standard size and thickness, and cultured at the air–liquid interface, can provide an important tool for understanding the mechanisms involved in several cutaneous disorders.

scholarly journals Staphylococcus aureus-Specific Tissue-Resident Memory CD4+ T Cells Are Abundant in Healthy Human Skin

2021 ◽  
Vol 12 ◽  
Author(s):  
Astrid Hendriks ◽  
Malgorzata Ewa Mnich ◽  
Bruna Clemente ◽  
Ana Rita Cruz ◽  
Simona Tavarini ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
T Cells ◽  
Human Skin ◽  
Ex Vivo ◽  
Functional Characterization ◽  
T Cell Response ◽  
Skin Microbiome ◽  
Entry Site ◽  
Healthy Human ◽  
Skin Explants

The skin is an immunocompetent tissue that harbors several kinds of immune cells and a plethora of commensal microbes constituting the skin microbiome. Staphylococcus aureus is a prominent skin pathogen that colonizes a large proportion of the human population. We currently have an incomplete understanding of the correlates of protection against S. aureus infection, however genetic and experimental evidence has shown that CD4+ T cells play a key role in orchestrating a protective anti-S. aureus immune response. A high S. aureus-specific memory CD4+ T cell response has been reported in the blood of healthy subjects. Since T cells are more abundant in the skin than in blood, we hypothesized that S. aureus-specific CD4+ T cells could be present in the skin of healthy individuals. Indeed, we observed proliferation of tissue-resident memory CD4+ T cells and production of IL-17A, IL-22, IFN-γ and TNF-β by cells isolated from abdominal skin explants in response to heat-killed S. aureus. Remarkably, these cytokines were produced also during an ex vivo epicutaneous S. aureus infection of human skin explants. These findings highlight the importance of tissue-resident memory CD4+ T cells present at barrier sites such as the skin, a primary entry site for S. aureus. Further phenotypical and functional characterization of these cells will ultimately aid in the development of novel vaccine strategies against this elusive pathogen.

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