scholarly journals Age-dependent increase in ortho-tyrosine and methionine sulfoxide in human skin collagen is not accelerated in diabetes. Evidence against a generalized increase in oxidative stress in diabetes.

1997 ◽  
Vol 100 (4) ◽  
pp. 839-846 ◽  
Author(s):  
M C Wells-Knecht ◽  
T J Lyons ◽  
D R McCance ◽  
S R Thorpe ◽  
J W Baynes
Keyword(s):  
Oxidative Stress ◽  
Human Skin ◽  
Methionine Sulfoxide ◽  
Skin Collagen ◽  
Age Dependent

Age-dependent accumulation of N.epsilon.-(carboxymethyl)lysine and N.epsilon.-(carboxymethyl)hydroxylysine in human skin collagen

Biochemistry ◽  
1991 ◽  
Vol 30 (5) ◽  
pp. 1205-1210 ◽  
Author(s):  
John A. Dunn ◽  
David R. McCance ◽  
Suzanne R. Thorpe ◽  
Timothy J. Lyons ◽  
John W. Baynes
Keyword(s):  
Human Skin ◽  
Skin Collagen ◽  
Age Dependent ◽  
Carboxymethyl Lysine

Heat-Shock Protein 90 (HSP90) in Age-Dependent Changes in the Fibroblast Number in Human Skin

2020 ◽  
Vol 10 (3) ◽  
pp. 260-265
Author(s):  
A. G. Gunin ◽  
N. N. Golubtzova ◽  
N. K. Kornilova
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Human Skin ◽  
Heat Shock Protein 90 ◽  
Age Dependent

scholarly journals An unusual thioredoxin system in the facultative parasite Acanthamoeba castellanii

2021 ◽  
Vol 78 (7) ◽  
pp. 3673-3689
Author(s):  
David Leitsch ◽  
Alvie Loufouma Mbouaka ◽  
Martina Köhsler ◽  
Norbert Müller ◽  
Julia Walochnik
Keyword(s):  
Oxidative Stress ◽  
Stop Codon ◽  
Acanthamoeba Castellanii ◽  
Methionine Sulfoxide ◽  
Redox System ◽  
Methionine Sulfoxide Reductase ◽  
Methionine Sulfoxide Reductase A ◽  
Protein Levels ◽  
Thioredoxin System ◽  
Facultative Parasite

AbstractThe free-living amoeba Acanthamoeba castellanii occurs worldwide in soil and water and feeds on bacteria and other microorganisms. It is, however, also a facultative parasite and can cause serious infections in humans. The annotated genome of A. castellanii (strain Neff) suggests the presence of two different thioredoxin reductases (TrxR), of which one is of the small bacterial type and the other of the large vertebrate type. This combination is highly unusual. Similar to vertebrate TrxRases, the gene coding for the large TrxR in A. castellanii contains a UGA stop codon at the C-terminal active site, suggesting the presence of selenocysteine. We characterized the thioredoxin system in A. castellanii in conjunction with glutathione reductase (GR), to obtain a more complete understanding of the redox system in A. castellanii and the roles of its components in the response to oxidative stress. Both TrxRases localize to the cytoplasm, whereas GR localizes to the cytoplasm and the large organelle fraction. We could only identify one thioredoxin (Trx-1) to be indeed reduced by one of the TrxRases, i.e., by the small TrxR. This thioredoxin, in turn, could reduce one of the two peroxiredoxins tested and also methionine sulfoxide reductase A (MsrA). Upon exposure to hydrogen peroxide and diamide, only the small TrxR was upregulated in expression at the mRNA and protein levels, but not the large TrxR. Our results show that the small TrxR is involved in the A. castellanii’s response to oxidative stress. The role of the large TrxR, however, remains elusive.

scholarly journals Hypermetabolism of glutathione, glutamate and ornithine via redox imbalance in methylglyoxal-induced peritoneal injury rats

2019 ◽  
Author(s):  
Ichiro Hirahara ◽  
Eiji Kusano ◽  
Denan Jin ◽  
Shinji Takai
Keyword(s):  
Oxidative Stress ◽  
Intraperitoneal Administration ◽  
Methionine Sulfoxide ◽  
Mesenchymal Cell ◽  
Oxidative Stress Marker ◽  
Peritoneal Fibrosis ◽  
Metabolome Analysis ◽  
Glycation End Products ◽  
Excessive Proliferation

Abstract Peritoneal dialysis (PD) is a blood purification treatment for patients with reduced renal function. However, the peritoneum is exposed to oxidative stress during PD and long-term PD results in peritoneal damage, leading to the termination of PD. Methylglyoxal (MGO) contained in commercial PD fluids is a source of strong oxidative stress. The aim of this study was to clarify the mechanism of MGO-induced peritoneal injury using metabolome analysis in rats. We prepared peritoneal fibrosis rats by intraperitoneal administration of PD fluids containing MGO for 21 days. As a result, MGO-induced excessive proliferation of mesenchymal cells with an accumulation of advanced glycation end-products (AGEs) at the surface of the thickened peritoneum in rats. The effluent levels of methionine sulfoxide, an oxidative stress marker and glutathione peroxidase activity were increased in the MGO-treated rats. The levels of glutathione, glutamate, aspartate, ornithine and AGEs were also increased in these rats. MGO upregulated the gene expression of transporters and enzymes related to the metabolism of glutathione, glutamate and ornithine in the peritoneum. These results suggest that MGO may induce peritoneal injury with mesenchymal cell proliferation via increased redox metabolism, directly or through the formation of AGEs during PD.

Capturing Age-Dependent Properties of Human Skin Using Magnetorheological Elastomers

2018 ◽  
Author(s):  
Kyle Weaver ◽  
Jeong-Hoi Koo ◽  
Tae-Heon Yang ◽  
Young-Min Kim
Keyword(s):  
Mechanical Properties ◽  
Human Skin ◽  
Skin Testing ◽  
Filler Particle ◽  
Variable Stiffness ◽  
Particle Volume ◽  
Magnetorheological Elastomers ◽  
Age Dependent ◽  
Skin Samples

Artificial and synthetic skins are widely used in the medical field; used in applications ranging from skin grafts to suture training pads. There is a growing need for artificial skins with tunable properties. However, current artificial skins do not take into account the variability of mechanical properties between individual humans as well as the age-dependent properties of human skin. Furthermore, there has been little development in artificial skins based on these properties. Thus, the primary purpose of this research is to develop variable stiffness artificial skin samples using magnetorheological elastomers (MREs) whose properties that can be controlled using external magnetic fields. In this study, multiple MRE skin samples were fabricated with varying filler particle volume contents. Using a precision dynamic mechanical analyzer, a series of indenting experiments were performed on the samples to characterize their mechanical properties. The samples were tested using a spherical indenter that indented a total depth of 1 mm with a speed of 0.01 mm/s and unloaded at the same rate. The results show that the modulus or stiffness increases significantly as the iron percent (w/w) in the sample increases. Additionally, the stiffness of the sample increases proportional to the intensity of the applied external magnetic field. To assess the MRE samples’ variability of properties, the testing results were compared with in vivo human skin testing data. The results show the MRE samples are feasible to represent the age-dependent stiffness demonstrated in in vivo human skin testing. The MRE materials studied will be further studied as a variable-stiffness skin model in medical devices, such as radial pulse simulators.

scholarly journals Assessment of Human Skin Gene Expression by Different Blends of Plant Extracts with Implications to Periorbital Skin Aging

2018 ◽  
Vol 19 (11) ◽  
pp. 3349 ◽  
Author(s):  
Jin Namkoong ◽  
Dale Kern ◽  
Helen Knaggs
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Human Skin ◽  
Barrier Function ◽  
Skin Barrier ◽  
Skin Aging ◽  
Skin Barrier Function ◽  
Oxidative Stress Biomarkers ◽  
Stress Biomarkers ◽  
And Oxidative Stress

Since the skin is the major protective barrier of the body, it is affected by intrinsic and extrinsic factors. Environmental influences such as ultraviolet (UV) irradiation, pollution or dry/cold air are involved in the generation of radical oxygen species (ROS) and impact skin aging and dermal health. Assessment of human skin gene expression and other biomarkers including epigenetic factors are used to evaluate the biological/molecular activities of key compounds in cosmetic formulas. The objective of this study was to quantify human gene expression when epidermal full-thickness skin equivalents were exposed to: (a) a mixture of betaine, pentylene glycol, Saccharomyces cerevisiae and Rhodiola rosea root extract (BlendE) for antioxidant, skin barrier function and oxidative stress (with hydrogen peroxide challenge); and (b) a mixture of Narcissus tazetta bulb extract and Schisandra chinensis fruit extract (BlendIP) for various biomarkers and microRNA analysis. For BlendE, several antioxidants, protective oxidative stress biomarkers and many skin barrier function parameters were significantly increased. When BlendE was evaluated, the negative impact of the hydrogen peroxide was significantly reduced for the matrix metalloproteinases (MMP 3 and MMP 12), the skin aging and oxidative stress biomarkers, namely FBN2, ANXA1 and HGF. When BlendIP was tested for cell proliferation and dermal structural components to enhance the integrity of the skin around the eyes: 8 growth factors, 7 signaling, 7 structural/barrier function and 7 oxidative stress biomarkers were significantly increased. Finally, when BlendIP was tested via real-time RT-PCR for microRNA expression: miR-146a, miR-22, miR155, miR16 and miR21 were all significantly increased over control levels. Therefore, human skin gene expression studies are important tools to assess active ingredient compounds such as plant extract blends to advance dermal hypotheses toward validating cosmetic formulations with botanical molecules.

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