scholarly journals Wavelength, dose, skin type and skin model related radical formation in skin

2021 ◽  
Author(s):  
M. C. Meinke ◽  
L. Busch ◽  
S. B. Lohan
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Cell Damage ◽  
Skin Aging ◽  
Skin Type ◽  
Radical Formation ◽  
Oxygen Species ◽  
High Exposure ◽  
Irradiation Wavelength

Abstract The exposure to sun radiation is indispensable to our health; however, a long-term and high exposure could lead to cell damage, erythema, premature skin aging, and promotion of skin tumors. An underlying pathomechanism is the formation of free radicals which may induce oxidative stress at elevated concentrations. Different skin models, such as porcine-, murine-, human- ex vivo skin, reconstructed human skin (RHS) and human skin in vivo, were investigated during and after irradiation using X- and L-band EPR spectroscopy within different spectral regions (UVC to NIR). The amount of radical formation was quantified with the spin probe PCA and the radical types were measured ex vivo with the spin trap DMPO. The radiation dose influences the types of radicals formed in the skin. While reactive oxygen species (ROS) are always pronounced at low doses, there is an increase in lipid oxygen species (LOS) at high doses. Furthermore, the radical types arise independent from the irradiation wavelength, whereas the general amount of radical formation differs with the irradiation wavelength. Heat pre-stressed porcine skin already starts with higher LOS values. Thus, the radical type ratio might be an indicator of stress and the reversal of ROS/LOS constitutes the point where positive stress turns into negative stress.Compared to light skin types, darker types produce less radicals in the ultraviolet, similar amounts in the visible and higher ones in the infrared spectral region, rendering skin type-specific sun protection a necessity.

scholarly journals Ocular Toxoplasmosis: Mechanisms of Retinal Infection and Experimental Models

Parasitologia ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 50-60
Author(s):  
Veronica Rodriguez Fernandez ◽  
Giovanni Casini ◽  
Fabrizio Bruschi
Keyword(s):  
Ex Vivo ◽  
Cell Damage ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Treatment Strategies ◽  
Experimental Models ◽  
Ocular Toxoplasmosis ◽  
Cell Infection

Ocular toxoplasmosis (OT) is caused by the parasite Toxoplasma gondii and affects many individuals throughout the world. Infection may occur through congenital or acquired routes. The parasites enter the blood circulation and reach both the retina and the retinal pigment epithelium, where they may cause cell damage and cell death. Different routes of access are used by T. gondii to reach the retina through the retinal endothelium: by transmission inside leukocytes, as free parasites through a paracellular route, or after endothelial cell infection. A main feature of OT is the induction of an important inflammatory state, and the course of infection has been shown to be influenced by the host immunogenetics. On the other hand, there is evidence that the T. gondii phenotype also has an impact on the distribution of the pathology in different areas. Although considerable knowledge has been acquired on OT, a deeper knowledge of its mechanisms is necessary to provide new, more targeted treatment strategies. In particular, in addition to in vitro and in vivo experimental models, organotypic, ex vivo retinal explants may be useful in this direction.

scholarly journals The NADPH Oxidase Nox4 Controls Macrophage Polarization in an NFκB-Dependent Manner

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
V. Helfinger ◽  
K. Palfi ◽  
A. Weigert ◽  
K. Schröder
Keyword(s):  
Ex Vivo ◽  
Macrophage Polarization ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Superoxide Anions ◽  
Wild Type ◽  
Macrophage Population ◽  
The Family ◽  
High Level

The family of NADPH oxidases represents an important source of reactive oxygen species (ROS) within the cell. Nox4 is a special member of this family as it constitutively produces H2O2 and its loss promotes inflammation. A major cellular component of inflammation is the macrophage population, which can be divided into several subpopulations depending on their phenotype, with proinflammatory M(LPS+IFNγ) and wound-healing M(IL4+IL13) macrophages being extremes of the functional spectrum. Whether Nox4 is expressed in macrophages is discussed controversially. Here, we show that macrophages besides a high level of Nox2 indeed express Nox4. As Nox4 contributes to differentiation of many cells, we hypothesize that Nox4 plays a role in determining the polarization and the phenotype of macrophages. In bone marrow-derived monocytes, ex vivo treatment with LPS/IFNγ or IL4/IL13 results in polarization of the cells into M(LPS+IFNγ) or M(IL4+IL13) macrophages, respectively. In this ex vivo setting, Nox4 deficiency reduces M(IL4+IL13) polarization and forces M(LPS+IFNγ). Nox4-/- M(LPS+IFNγ)-polarized macrophages express more Nox2 and produce more superoxide anions than wild type M(LPS+IFNγ)-polarized macrophages. Mechanistically, Nox4 deficiency reduces STAT6 activation and promotes NFκB activity, with the latter being responsible for the higher level of Nox2 in Nox4-deficient M(LPS+IFNγ)-polarized macrophages. According to those findings, in vivo, in a murine inflammation-driven fibrosarcoma model, Nox4 deficiency forces the expression of proinflammatory genes and cytokines, accompanied by an increase in the number of proinflammatory Ly6C+ macrophages in the tumors. Collectively, the data obtained in this study suggest an anti-inflammatory role for Nox4 in macrophages. Nox4 deficiency results in less M(IL4+IL13) polarization and suppression of NFκB activity in monocytes.

scholarly journals Nanostructured Lipid Carrier Gel for the Dermal Application of Lidocaine: Comparison of Skin Penetration Testing Methods

Pharmaceutics ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 310 ◽  
Author(s):  
Stella Zsikó ◽  
Kendra Cutcher ◽  
Anita Kovács ◽  
Mária Budai-Szűcs ◽  
Attila Gácsi ◽  
...  
Keyword(s):  
Drug Release ◽  
Human Skin ◽  
Ex Vivo ◽  
Study Drug ◽  
Skin Penetration ◽  
Human Epidermis ◽  
Nanostructured Lipid Carrier ◽  
Experimental Findings

The aim of this research was to investigate the stability of a lidocaine-loaded nanostructured lipid carrier dispersion at different temperatures, formulate a nanostructured lipid carrier gel, and test the penetration profile of lidocaine from the nanostructured lipid carrier gel using different skin penetration modeling methods. The formulations were characterized by laser diffraction, rheological measurements and microscopic examinations. Various in vitro methods were used to study drug release, diffusion and penetration. Two types of vertical Franz diffusion cells with three different membranes, including cellulose, Strat-M®, and heat separated human epidermis were used and compared to the Skin-parallel artificial membrane permeability assay (PAMPA) method. Results indicated that the nanostructured lipid carrier dispersion had to be gelified as soon as possible for proper stability. Both the Skin-PAMPA model and Strat-M® membranes correlated favorably with heat separated human epidermis in this research, with the Strat-M® membranes sharing the most similar drug permeability profile to an ex vivo human skin model. Our experimental findings suggest that even when the best available in vitro experiment is selected for modeling human skin penetration to study nanostructured lipid carrier gel systems, relevant in vitro/in vivo correlation should be made to calculate the drug release/permeation in vivo. Future investigations in this field are still needed to demonstrate the influence of membranes and equipment from other classes on other drug candidates.

scholarly journals Compromising human skin in vivo and ex vivo to study skin barrier repair

2019 ◽  
Vol 1864 (8) ◽  
pp. 1103-1108 ◽  
Author(s):  
T. Berkers ◽  
W.A. Boiten ◽  
S. Absalah ◽  
J. van Smeden ◽  
A.P.M. Lavrijsen ◽  
...  
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Skin Barrier ◽  
Barrier Repair ◽  
Skin Barrier Repair

scholarly journals Effect of Skin Model on In Vitro Performance of an Adhesive Dermally Applied Microarray Coated with Zolmitriptan

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Mahmoud Ameri ◽  
Hayley Lewis ◽  
Paul Lehman
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Full Thickness ◽  
Artificial Membrane ◽  
Skin Model ◽  
Hydrophobic Membrane ◽  
Thickness Skin ◽  
In Vitro Performance

Franz cell studies, utilizing different human skin and an artificial membrane, evaluating the influence of skin model on permeation of zolmitriptan coated on an array of titanium microprojections, were evaluated. Full thickness and dermatomed ex vivo human skin, as well as a synthetic hydrophobic membrane (Strat-M®), were assessed. It was found that the choice of model demonstrated different absorption kinetics for the permeation of zolmitriptan. For the synthetic membrane only 11% of the zolmitriptan coated dose permeated into the receptor media, whilst for the dermatomed skin 85% permeated into the receptor. The permeation of zolmitriptan through full thickness skin had a significantly different absorption profile and time to maximum flux in comparison to the dermatomed skin and synthetic model. On the basis of these results dermatomed skin may be a better estimate of in vivo performance of drug-coated metallic microprojections.

scholarly journals FLAME: Macroscopic imaging with microscopic resolution. Optical biopsy of human skin

2020 ◽  
Author(s):  
Alexander Fast ◽  
Akarsh Lal ◽  
Amanda F. Durkin ◽  
Christopher B. Zachary ◽  
Anand K. Ganesan ◽  
...  
Keyword(s):  
Human Skin ◽  
Single Photon ◽  
Ex Vivo ◽  
Photon Counting ◽  
Optical Biopsy ◽  
Large Area ◽  
Time Resolved ◽  
Distribution Maps ◽  
Imaging Tool

AbstractWe introduce a compact, fast large area multiphoton exoscope (FLAME) system with enhanced molecular contrast for macroscopic imaging of human skin with microscopic resolution. A versatile imaging platform with multiple modes of operation for comprehensive analysis of live or resected thick human skin tissue, it produces 3D images that encompass sub-mm2 to cm2 scale areas of tissue within minutes. The FLAME imaging platform, which expands on a design recently introduced by our group, features deep learning, additional scanning hardware elements and time-resolved single photon counting detection to uniquely allow fast discrimination and 3D virtual staining of melanin. We demonstrate its performance and utility by fast ex vivo and in vivo imaging of human skin. With the ability to provide rapid access to depth resolved images of skin over cm2 area and to generate 3D distribution maps of key sub-cellular skin components such as melanocytic dendrites and melanin, FLAME represents a promising imaging tool for enhancing diagnosis accuracy, guiding therapy and understanding skin biology.

scholarly journals Neuronal Replacement in Stem Cell Therapy for Stroke: Filling the Gap

2021 ◽  
Vol 9 ◽  
Author(s):  
Sara Palma-Tortosa ◽  
Berta Coll-San Martin ◽  
Zaal Kokaia ◽  
Daniel Tornero
Keyword(s):  
Stem Cell ◽  
Animal Models ◽  
Cell Therapy ◽  
Human Skin ◽  
Stem Cell Therapy ◽  
Ex Vivo ◽  
Functional Integration ◽  
Short Review ◽  
Neuronal Replacement

Stem cell therapy using human skin-derived neural precursors holds much promise for the treatment of stroke patients. Two main mechanisms have been proposed to give rise to the improved recovery in animal models of stroke after transplantation of these cells. First, the so called by-stander effect, which could modulate the environment during early phases after brain tissue damage, resulting in moderate improvements in the outcome of the insult. Second, the neuronal replacement and functional integration of grafted cells into the impaired brain circuitry, which will result in optimum long-term structural and functional repair. Recently developed sophisticated research tools like optogenetic control of neuronal activity and rabies virus monosynaptic tracing, among others, have made it possible to provide solid evidence about the functional integration of grafted cells and its contribution to improved recovery in animal models of brain damage. Moreover, previous clinical trials in patients with Parkinson’s Disease represent a proof of principle that stem cell-based neuronal replacement could work in humans. Our studies with in vivo and ex vivo transplantation of human skin-derived cells neurons in animal model of stroke and organotypic cultures of adult human cortex, respectively, also support the hypothesis that human somatic cells reprogrammed into neurons can get integrated in the human lesioned neuronal circuitry. In the present short review, we summarized our data and recent studies from other groups supporting the above hypothesis and opening new avenues for development of the future clinical applications.

scholarly journals Biocompatible near-infrared quantum dots delivered to the skin by microneedle patches record vaccination

2019 ◽  
Vol 11 (523) ◽  
pp. eaay7162 ◽  
Author(s):  
Kevin J. McHugh ◽  
Lihong Jing ◽  
Sean Y. Severt ◽  
Mache Cruz ◽  
Morteza Sarmadi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Human Skin ◽  
Data Storage ◽  
Near Infrared ◽  
Learning Algorithm ◽  
Ex Vivo ◽  
Neutralizing Antibody ◽  
Nir Light ◽  
Antibody Titers

Accurate medical recordkeeping is a major challenge in many low-resource settings where well-maintained centralized databases do not exist, contributing to 1.5 million vaccine-preventable deaths annually. Here, we present an approach to encode medical history on a patient using the spatial distribution of biocompatible, near-infrared quantum dots (NIR QDs) in the dermis. QDs are invisible to the naked eye yet detectable when exposed to NIR light. QDs with a copper indium selenide core and aluminum-doped zinc sulfide shell were tuned to emit in the NIR spectrum by controlling stoichiometry and shelling time. The formulation showing the greatest resistance to photobleaching after simulated sunlight exposure (5-year equivalence) through pigmented human skin was encapsulated in microparticles for use in vivo. In parallel, microneedle geometry was optimized in silico and validated ex vivo using porcine and synthetic human skin. QD-containing microparticles were then embedded in dissolvable microneedles and administered to rats with or without a vaccine. Longitudinal in vivo imaging using a smartphone adapted to detect NIR light demonstrated that microneedle-delivered QD patterns remained bright and could be accurately identified using a machine learning algorithm 9 months after application. In addition, codelivery with inactivated poliovirus vaccine produced neutralizing antibody titers above the threshold considered protective. These findings suggest that intradermal QDs can be used to reliably encode information and can be delivered with a vaccine, which may be particularly valuable in the developing world and open up new avenues for decentralized data storage and biosensing.

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