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Accumulation of oxidative insults on molecular and supramolecular levels could compromise renewal potency and architecture in the aging skin. To examine and compare morphological and ultrastructural changes with redox alterations during chronological skin aging, activities of antioxidant defense (AD) enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), thioredoxin reductase (TR), and methionine sulfoxide reductase A (MsrA), and the markers of oxidative damage of biomolecules—4-hydroxynonenal (HNE) and 8-oxoguanine (8-oxoG)—were examined in the rat skin during life (from 3 days to 21 months). As compared to adult 3-month-old skin, higher activities of CAT, GSH-Px, and GR and a decline in expression of MsrA are found in 21-month-old skin. These changes correspond to degenerative changes at structural and ultrastructural levels in epidermal and dermal compartments, low proliferation capacity, and higher levels of HNE-modified protein aldehydes (particularly in basal lamina) and 8-oxoG positivity in nuclei and mitochondria in the sebaceous glands and root sheath. In 3-day-old skin, higher activities of AD enzymes (SOD, CAT, GR, and TR) and MsrA expression correspond to intensive postnatal development and proliferation. In contrast to 21-month-old skin, a high level of HNE in young skin is not accompanied by 8-oxoG positivity or any morphological disturbances. Observed results indicate that increased activity of AD enzymes in elderly rat skin represents the compensatory response to accumulated oxidative damage of DNA and proteins, accompanied by attenuated repair and proliferative capacity, but in young rats the redox changes are necessary and inherent with processes which occur during postnatal skin development. Мorphological and ultrastructurаl changes are in line with the redox profile in the skin of young and old rats.

Patients with severe burns are highly susceptible to bacterial infection. While immunosuppression facilitates infection, the contribution of soft tissues to infection beyond providing a portal for bacterial entry remains unclear. We showed previously that glutathione S-transferase S1 (gstS1), an enzyme with conjugating activity against the lipid peroxidation byproduct 4-hydroxynonenal (4HNE), is important for resistance against wound infection in Drosophila muscle. The importance of the mammalian functional counterpart of GstS1 in the context of wounds and infection has not been investigated. Here we demonstrate that the presence of a burn wound dramatically affects expression of both human (hGSTA4) and mouse (mGsta4) 4HNE scavengers. hGSTA4 is down-regulated significantly within 1 wk of thermal burn injury in the muscle and fat tissues of patients from the large-scale collaborative Inflammation and the Host Response to Injury multicentered study. Similarly, mGsta4, the murine GST with the highest catalytic efficiency for 4HNE, is down-regulated to approximately half of normal levels in mouse muscle immediately postburn. Consequently, 4HNE protein adducts are increased 4- to 5-fold in mouse muscle postburn. Using an open wound infection model, we show that deletion of mGsta4 renders mice more susceptible to infection with the prevalent wound pathogen Pseudomonas aeruginosa, while muscle hGSTA4 expression negatively correlates with burn wound infection episodes per patient. Our data suggest that hGSTA4 down-regulation and the concomitant increase in 4HNE adducts in human muscle are indicative of susceptibility to infection in individuals with severely thermal injuries.—Apidianakis, Y., Que, Y.-A., Xu, W., Tegos, G. P., Zimniak, P., Hamblin, M. R., Tompkins, R. G., Xiao, W., Rahme, L. G. Down-regulation of glutatione S-transferase α 4 (hGSTA4) in the muscle of thermally injured patients is indicative of susceptibility to bacterial infection.

In amyotrophic lateral sclerosis (ALS) reactive oxygen species and apoptosis are implicated in disease pathogenesis. Melatonin with its anti-oxidant and anti-apoptotic properties is expected to ameliorate disease phenotype. The aim of this study was to assess possible neuroprotection of melatonin in the G93A-copper/zinc superoxide dismutase (G93ASOD1) transgenic mouse model of ALS. Four groups of mice, 14 animals each, were injected intraperitoneally with 0 mg/kg, 0.5 mg/kg, 2.5 mg/kg and 50 mg/kg of melatonin from age 40 days. The primary end points were; disease onset, disease duration, survival and rotarod performance. No statistically significant difference in disease onset between the four groups was found. Survival was significantly reduced with the 0.5 mg/kg and 50 mg/kg doses and tended to be reduced with the 2.5 mg/kg dose. Histological analysis of spinal cords revealed increased motoneuron loss in melatonin treated mice. Melatonin treated animals were associated with increased oxidative stress as assessed with 4-hydroxynonenal (4-HNE), a marker of lipid peroxidation. Histochemistry and Western blot data of spinal cord from melatonin treated mice revealed upregulation of human SOD1 compared to untreated mice. In addition, real-time PCR revealed a dose dependent upregulation of human SOD1 in melatonin treated animals. Thus, intraperitoneal melatonin, at the doses used, does not ameliorate and perhaps exacerbates phenotype in the G93ASOD1 mouse ALS model. This is probably due to melatonin's effect on upregulating gene expression of human toxic SOD1. This action presumably overrides any of its direct anti-oxidant and anti-apoptotic properties. Fil: Dardiotis, Efthimios . The Cyprus Institute of Neurology and Genetics; Chipre Fil: Panayiotou, Elena . The Cyprus Institute of Neurology and Genetics; Chipre Fil: Feldman, Mariana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina Fil: Hadjisavvas, Andreas . The Cyprus Institute of Neurology and Genetics; Chipre Fil: Malas, Stavros . The Cyprus Institute of Neurology and Genetics; Chipre Fil: Vonta, Ilia. National Technical University of Athens; Grecia Fil: Hadjigeorgiou, Georgios . Centre for Research and Technology-Thessaly; Grecia Fil: Kyriakou, Kyriakos . The Cyprus Institute of Neurology and Genetics; Chipre Fil: Kyriakides, Theodoros . The Cyprus Institute of Neurology and Genetics; Chipre