Epidermal barrier and oxidative stress parameters improve during in 311 nm narrow band UVB phototherapy of plaque type psoriasis.

BACKGROUND: Psoriasis is a multi-systemic inflammatory disease that results from dysregulation between epidermal keratinocyte homeostasis and both innate and acquired immunity. Epidermal barrier defect has been described in psoriatic lesions. Furthermore an imbalance between pro-oxidative stress and antioxidant defense mechanisms are known in psoriasis patients. AIM: The aim of this study was to address the link between disease activity, epidermal barrier and systemic oxidative stress in the course of 311 nm narrow band ultraviolet B (NB-UVB) therapy of psoriasis. The dynamic of systemic oxidative stress parameters as well as local transepidermal water loss (TEWL) and stratum corneum hydration (SCH) was characterized before and after 311 nm NB-UVB therapy on the plaques of psoriasis vulgaris in comparison to untreated non-affected volar forearm sites of the same patients. MATERIAL AND METHODS: 22 patients with plaque type psoriasis vulgaris and 25 gender- and age-matched healthy controls were enrolled. We assessed the psoriasis area and severity index (PASI) and the dermatology life quality index (DLQI) for monitoring disease activity, severity and self-perceived DLQI impact as patient related outcome parameter. We measured non-invasively TEWL (Tewameter TM 300) and SCH (Corneometer CM 825) and the end product of lipid peroxidation - malondialdehyde (MDA), Reactive oxygen species (ROS), ascorbyl radicals (Asc) and detoxifying activity of catalase (CAT) were measured in the peripheral blood with spectrophotometric and EPR spectroscopy methods. RESULTS: Disease activity improved in all patients compared to baseline witnessed by significant decrease in PASI; (from 14.1 to 10.4; p < 0.0001) and DLQI (from 11.7 to 8.1; p < 0.0001). At baseline TEWL-values were significantly (p < 0.0001) higher on psoriatic plaques (16.8 g/h/m2) in comparison to uninvolved skin (5.3 g/h/m2); with a decrease at both sites after NB-UVB phototherapy. SCH was significantly lower at psoriatic plaque s (4.7AU) compared to uninvolved sskin (42.4AU) and increased after treatment (8.6AU) (p < 0.0001). Interestingly, SCH decrease slightly during therapy at uninvolved skin (40.6AU). ROS and Asc declined during therapy in parallel to a decrease in MDA. A mild decrease in the antioxidative enzyme CAT activity which did not reach the significance was observed. CONCLUSION: The presented data is shows that a clinical improvement of psoriatic plaques under NB-UVB therapy, shown in with a decreased PASI and reflected by an increase in quality of life has beneficial effects on epidermal barrier function, SCH and improvement of systemic oxidative stress parameters (ROS, MDA and Asc). We assume that the general improvement in the oxidative stress parameters along with epidermal barrier parameters reflects mainly the improvement of disease activity which overwrites the possible negative pro-oxidative effects of the UV treatment.

Influence of glycemic control on some real-time biomarkers of free radical formation in type 2 diabetic patients: An EPR study.

BACKGROUND: The pathology of diabetes is associated with several mechanisms, one of which is oxidative stress (OS). The relationship between OS and diabetic complications has been extensively investigated. OS has been suggested to be involved in the genesis of both macroand microangiopathy. In contrast, the relationship between OS and insulin action is a neglected research area. OBJECTIVES: The aim of this study is to elucidate the effect of glycemic control in type 2 diabetic patients by following the serum levels of some real-time oxidative stress biomarkers. MATERIAL AND METHODS: The study group consisted of 53 type 2 diabetic patients (31 with poor glycemic control and 22 with good glycemic control) and 24 healthy control subjects. The oxidative stress biomarkers (ROS, Asc• and •NO) were measured by using electron paramagnetic resonance spectroscopy (EPR) methods and compared with clinical parameters. RESULTS: The statistically significantly higher levels of ROS products and •NO in type 2 diabetic patients in both groups compared to controls mean that the oxidation processes take place at the time the survey is performed. Free radical overproduction persists after the normalization of the glucose levels, and oxidative stress may be involved in the "metabolic memory" effect. This is confirmed by the positive correlation between ROS levels/•NO and average blood glucose levels, triglycerides, and total cholesterol. Furthermore, the low level of the ascorbate radical in both diabetes groups compared to controls confirmed an increase in oxidation processes. CONCLUSIONS: Higher levels of real-time biomarkers show that intensive insulin treatment does not lead to the expected decrease in oxidative processes involving ROS and •NO, probably due to "metabolic memory".

Protective effect of two essential oils isolated from Rosa damascena Mill. and Lavandula angustifolia Mill, and two classic antioxidants against L-dopa oxidative toxicity induced in healthy mice.

Levodopa (L-dopa) is a "gold standard" and most effective symptomatic agent in the Parkinson's disease (PD) treatment. The several treatments have been developed in an attempt to improve PD treatment, but most patients were still levodopa dependent. The issue of toxicity was raised in vitro studies, and suggests that L-dopa can be toxic to dopaminergic neurons, but it is not yet entirely proven. L-dopa prolonged treatment is associated with motor complications and some limitations. Combining the L-dopa therapy with antioxidants can reduce related sideeffects and provide symptomatic relief. The natural antioxidants can be isolated from any plant parts such as seeds, leaves, roots, bark, etc., and their extracts riched in phenols can retard the oxidative degradation of the lipids, proteins and DNA. Thus, study suggests that combination of essential oils (Rose oil and Lavender oil), Vitamin C and Trolox with Ldopa can reduce oxidative toxicity, and may play a key role in ROS/RNS disarm.

Biological evaluation of new potential anticancer agent for tumour imaging and radiotherapy by two methods: 99mTc-radiolabelling and EPR spectroscopy.

Recently, a new class of in vitro and ex vivo radiotracers/radioprotectors, the nitroxyl-labelled agent 1-ethyl-1-nitroso-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-urea (SLENU), has been discovered. Our previous investigations demonstrated that SLENU is a low-molecular-weight stable free radical which is freely membrane permeable, easily crosses the blood brain barrier and exhibited in/ex vivo the lowest general toxicity and higher anticancer activity against some experimental tumour models. Further investigation was aimed to develop a 99mTc-labelled SLENU (97%) as a chelator and evaluate its labelling efficiency and potential use as a tumour seeking agent and for early diagnosis. Tissue biodistribution of 99mTc-SLENU was determined in normal mice at 1, 2 and 24 h (n = 4/time interval, route of administration i.v.). The distribution data were compared using male albino non-inbred mice and electron paramagnetic resonance investigation. The imaging characteristics of 99mTc-SLENU conjugate examined in BALB/c mice grafted with Ehrlich Ascitis tumour in the thigh of hind leg demonstrated major accumulation of the radiotracer in the organs and tumour. Planar images and auto-radiograms confirmed that the tumours could be visualized clearly with 99mTc-SLENU. Blood kinetic study of radio-conjugate showed a bi-exponential pattern, as well as quick reduced duration in the blood circulation. This study establishes nitroxyls as a general class of new spin-labelled diagnostic markers that reduce the negative lateral effects of radiotherapy and drug damages, and are appropriate for tumour-localization.

Radical scavenging and radiomodulatory effects of Psoralea corylifolia Linn. substantiated by in vitro assays and EPR spectroscopy.

The present study is the first report of the radiomodulatory effects of Psoralea corylifolia Linn. The extract (IBG-RA-26) prepared from P. corylifolia was chemically analysed by HPLC, LC-MS/MS and NMR. The total polyphenolic content of IBG-RA-26 was 0.287 mg/ml of quercetin equivalents. IBG-RA-26 exhibited a dose-dependent increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. It exhibited comparable (> 50%) site-specific and non-site-specific hydroxyl radical scavenging activity in higher concentration ranges (500-1000 microg/ml), while at lower concentrations (5-50 microg/ml) it exhibited significantly (p < 0.05) higher non-site-specific scavenging ability compared to site-specific activity. Nitric oxide scavenging activity of IBG-RA-26 (5-1000 microg/ml) increased in a concentration-dependent manner, while maximum superoxide ion scavenging ability (79%) was observed at 50 microg/ml. The electron donation potential of IBG-RA-26 was found to be higher than that of ascorbic acid at lower concentrations (up to 5 microg/ml). Analysis of the ability of IBG-RA-26 to protect membranes against gamma-radiation, utilizing an artificial membrane system (liposome), revealed a significant (p < 0.05) decrease in the formation of malondialdehyde (MDA) as a function of the concentration of IBG-RA-26. Radiation-induced lysis of human erythrocytes was monitored and efficacy of IBG-RA-26 was tested in the concentration range 25-1000 microg/ml, with significant protective efficacy observed in the range 25-50 microg/ml. IBG-RA-26 rendered significant (p < 0.05) protection against radiation (0.25 kGy)-induced DNA damage. EPR spectroscopy was used to investigate the DPPH radical scavenging capacity of IBG-RA-26. IBG-RA-26 exhibited a good DPPH radical scavenging capacity in a concentration-dependent manner. By direct EPR spectroscopy we have also demonstrated the possible formation of free radical species in a solution of IBG-RA-26. The wide spectrum of radioprotective and antioxidant properties exhibited by IBG-RA-26 indicate that P. corylifolia has potential as a radiomodulatory agent.

Electron paramagnetic resonance spectroscopy in radiation research: Current status and perspectives.

Exposure to radiation leads to a number of health-related malfunctions. Ionizing radiation is more harmful than non-ionizing radiation, as it causes both direct and indirect effects. Irradiation with ionizing radiation results in free radical-induced oxidative stress. Free radical-mediated oxidative stress has been implicated in a plethora of diseased states, including cancer, arthritis, aging, Parkinson's disease, and so on. Electron Paramagnetic Resonance (EPR) spectroscopy has various applications to measure free radicals, in radiation research. Free radicals disintegrate immediately in aqueous environment. Free radicals can be detected indirectly by the EPR spin trapping technique in which these forms stabilize the radical adduct and produce characteristic EPR spectra for specific radicals. Ionizing radiation-induced free radicals in calcified tissues, for example, teeth, bone, and fingernail, can be detected directly by EPR spectroscopy, due to their extended stability. Various applications of EPR in radiation research studies are discussed in this review.

EPR signal reduction kinetic of several nitroxyl derivatives in blood in vitro and in vivo.

The present study is focused on the mechanism(s) of electron-paramagnetic resonance (EPR) signal reduction kinetic of several nitroxyl radicals and nitroxyl-labeled anticancer drugs in physiological solutions in the context of their application for evaluation of oxidation/reduction status of blood and tissues--an important step in biomedical diagnostics and planning of therapy of many diseases. The nitroxyl derivatives were characterized with different size and water-solubility. Some of them are originally synthesized. In buffer, in the absence of reducing and oxidizing equivalents, the EPR signal intensity of all nitroxyls was constant with the time. In serum and cell cultured medium, in an absence of cells and in a negligible amount of reducing and oxidizing equivalents, there was no significant EPR signal reduction, too. In vitro (in freshly isolated blood samples), the EPR signal intensity was characterized with slow decrease within 30 min, presumably as a result of interaction between the nitroxyl derivative and blood cells. The EPR spectrum of hydrophobic nitroxyls showed a slight anisotropy in cell-containing solutions and it did not changed in non-cell physiological solutions. This suggests for a limited motion of more hydrophobic nitroxyls through their preferable location in cell membranes. In vivo (in the bloodstream of mice under anesthesia), the EPR signal reduction kinetic was characterized by two phases: i) a rapid enhancement within 30 s as a result of increasing of nitroxyl concentration in the bloodstream after its intravenous injection, followed by ii) a rapid decrease (approximately 80-100%) within 2-5 min, presumably as a result of transportation of nitroxyl in the tissues. The hydrophobic nitroxyls were characterized with stronger and faster decrease in EPR signal intensity in the blood in vivo, as a result of their higher cell permeability, rapid clearance from the bloodstream and/or transportation in the surrounding tissues. The hydrophilic nitroxyls persist in the bloodstream (in their radical form) for a comparatively long time. The data suggest that the hydrophobic cell-permeable nitroxyl derivatives are most appropriate for evaluation of cell and tissue oxidation/reduction status, while the hydrophilic nitroxyls (impermeable for cell membranes or with very slow cell permeability) are most appropriate for evaluation of oxidation/reduction status of blood using EPR imaging.

Free radical reactions might contribute to severe alpha amanitin hepatotoxicity--a hypothesis.

Alpha amanitin is a powerful natural hepatotoxin that belongs to the amatoxins isolated from deadly poisonous Amanita phalloides mushroom. The basic molecular mechanism of their toxicity was attributed to inhibition of RNA polymerase II of the eukaryotic cells. At present, the most effective clinical antidote to acute Amanita phalloides mushroom poisoning is silybin, an antioxidant possessing free radical scavenger activity and inhibiting lipid peroxidation, stabilizing membrane structure and protecting enzymes under conditions of oxidative stress. Bearing in mind the biological mechanism of silybin action and the fact that for different amatoxins (alpha, beta, and est. amanitins) does not established straight correlation between their in vivo LD50 and inhibitory constants (Ki) toward RNA polymerase III in vitro determined we supposed some additional toxic effects of these toxins might contribute to their severe hepatotoxicity. Our formerly in vitro experiments demonstrated that alpha amanitin could act either as an antioxidant or as a prooxidant depending on the treatment conditions and toxin concentration. By UV-visible spectroscopy we also shown that alpha amanitin was sensitive to oxidation by a system of lactoperoxidase/H(2)O(2) and assumed formation of free radical toxin intermediates. Having in mind some exogenic compounds including natural toxins can induce increased production of reactive oxygen species (ROS) we suggested similar generation of ROS provoked by alpha amanitin. Our recently in vitro studies have demonstrated that the alpha amanitin could increase superoxide dismutase (SOD) activity and inhibit catalase (CAT) activity to a considerable degree after together incubation of the toxin with any of enzymes. We have also shown that in vitro increased SOD activity was due to superoxide anion radical scavenging activity (SSA) of the toxin. This therefore informed the decision to study the in vivo effect of alpha amanitin on SOD and CAT activity and the level of lipid peroxidation (LPO) products in liver homogenates isolated from mice treated with the toxin. Statistical significant increased level of LPO products was found at the 6th day comparing to the 20th hour after mice treatment with a subletal dose of the toxin. Based on our previous in vitro and present in vivo studies we have made a hypothesize that in vivo during liver accumulation of the toxin it might be transformed to free radical intermediates causing increase in ROS levels. As a result a peroxidative process in hepatocytes might contribute to the severe alpha amanitin hepatotoxicity.

Spin labeled antioxidants protect bacteria against the toxicity of alkylating antitumor drug CCNU.

We have studied the toxic effect of the alkylating antitumor drug N'-cyclohexyl-N-(2-chloroethyl)-N-nitrosourea (lomustine, CCNU) on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) strains, alone and in presence of oxygen radical-scavenging substances [Vitamin E, stable nitroxyl radical 2,2,6,6-tetramethylpiperidine-N-oxyl (TMPO), and spin labeled (nitroxyl free radical moiety containing) analogues of CCNU] and compared with that of the alkylating antitumor drug 5-(3,3-dimethyltriazene-1-yl)-imidazole-4-carboxamide (dacarbazine, DTIC). All spin labeled compounds tested were almost no toxic at doses of 50-500 microM/ml, whereas the alkylating antitumor drug CCNU showed toxicity in a dose dependent manner. Even low doses of spin labeled nitrosoureas provided protection against the toxicity caused by the antitumor drug CCNU alone. The lowest toxicity against E. coli and S. aureus were achieved when 500 microM/ml of CCNU was combined with 200 microM/ml of spin labeled nitrosourea N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl]-glycine amid of 2,2,6,6-tetramethyl-4-aminopiperidine-1-oxyl (SLCNUgly). A combination of TMPO with vitamin E completely abolished the toxicity of CCNU. Endogenous formation of oxygen radicals and their possible involvement in CCNU toxicity towards the bacteria strains tested have been also discussed.