Introduction Peter Celec, MD, Dipl. Ing, MSc, PhD, MPH
Literature Journals Indexed CC Current contents Impact factor
Literature Systematic searching Logical operators Specific operators [ti], [au] Review Date range limit Type of publication
Literature PubMed/Medline ISI Web of Science Publishers Elsevier/Sciencedirect Springer Willey Interscience
Literature Access to journals Libraries Google
Literature Open Access Biomednet Central PubMed Central Public Library of Science
Clinical studies Empirical medicine Expert opinion Evidence-based medicine Guidelines Individualized medicine
Meta-analyses Cohorts from several clinical studies Statistical analysis High informative value The weight of large numbers
Oxidative and carbonyl stress Peter Celec, MD, Dipl. Ing, MSc, PhD, MPH
Introduction Oxidative and carbonyl stress Definitions Sources and causes Consequences Markers The role in the pathogenesis of diseases Therapeutic influences
Definitions Free radical Atom or molecule with an unpaired – free electron Reactive oxygen/nitrogen species – ROS/RNS Highly reactive molecule
ROS Free radicals Superoxide. O 2 - Hydroxyl. OH Peroxyl ROO. Alkoxyl RO. Hydroperoxyl HO 2. Molecular oxygen O 2 Others Hydrogen peroxide H 2 O 2 Hypochlorous acid HClO Ozone O 3 Singlet oxygen 1 O 2
ROS
Fenton reaction Fe 2+ + H 2 O 2 → Fe OH + OH - . O Fe 3+ → O 2 + Fe 2+ . O H 2 O 2 → O 2 +. OH + OH - Catalytic effect of metal ions
RNS Free radicals Nitric oxide. NO Nitric dioxide. NO 2 Others Nitrozyl NO + Nitrous acid HNO 2 Nitric trioxide N 2 O 3 Peroxynitrite ONOO - Alkylperoxynitrite ROONO
Endogen sources of ROS – reactions Autooxidation (Fenton reaction) Hemoglobin, myoglobin, reduced thiols, cytochrome C, catecholamines Respiratory burst NADPH oxidase Other enzymatic production Prostaglandin synthase, lipoxygenase, myeloperoxidase, xantin oxidase
Endogen sources of ROS – organels Mitochondria Terminal oxidation & Oxidative phosphorylation Electron transport system – cytochrome oxidase Superoxide anion radical Hyperoxia / hypoxia
Endogen sources of ROS – organels Endoplasmatic reticulum Oxidation-reduction reactions Metabolism of xenobiotics Cytochrome P450 Microsomes – Peroxisomes Metabolism of fatty acids Hydrogen peroxide
Exogen sources of ROS Drugs Nitrofurantoin, antracyclins, metotrexate, sulfasalasine Radiation X-rays, radiotherapy, UV Smoking Ozone
Sources of RNS NO synthases Endothelial Inducible Neuronal Reaction of. NO and. O 2 -
Physiological functions of ROS Detoxification of xenobiotics Monoxygenases, cytochrome oxidases Immune response & Phagocytosis Myeloperoxidases NADPH oxidase Signalling pathways
Physiological functions of RNS Currently known only for. NO Vasodilatation Paracrine communication Neuromediator Nitrosylation
Damage caused by ROS Lipids Lipoperoxidation XNA Damage of bases – mutations Proteins Carbonylation of proteins Cross-linking
Antioxidants Antioxidative status Inhibition of production Scavenging Correction mechanisms
Antioxidants Endogen Exogen Low molecular weight (LMW; non- enzymatic) High molecular weight (HMW; enzymatic)
HMW antioxidants Enzymatic antioxidants Superoxide dismutase SOD Catalase CAT Glutathione peroxidase/reductase
HMW antioxidants Superoxide dismutase Mitochondrial MnSOD Cytoplasmatic CuZn Extracellular CuZn
SOD In all aerobic organisms Even in procaryotic organisms . O O H + → H 2 O 2 + O 2
CAT In all eucaryotic aerobic organisms Dismutation of hydrogen peroxide 2 H 2 O 2 → 2 H 2 O + O 2
Glutathione system Glutathione (GSH) Glu-Cys-Gly -SH group on cysteine residue LMW antioxidant Scavenger of free radicals 2 GSH +. O 2 - → GSSG + H 2 O Most important cytoplasmatic antioxidant
Glutathione system Only in animals Glutathione peroxidase Contains selenocysteine Reduces hydrogen peroxide using glutathione 2 GSH + H 2 O 2 → GSSG + 2 H 2 O Glutathione reductase GSSG + NADPH + H + → 2 GSH + NADP +
Antioxidant metabolic pathways
LMW antioxidants Glutathione Vitamins C, E Karotenoids Coenzyme Q 10 Tanins, Flavonoids Proline ...
Balance OxidantsAntioxidants
Oxidative stress Disbalance beteen the production of free radicals and antioxidative mechanisms In the pathogenesis......of everything
Markers of oxidative stress EPR Damage of lipids Malondialdehyde, 4-OH-2-nonenal, 8-isoprostane Damage of DNA 8-OH-guanine Damage of proteins Dityrosine, carbonylated proteins
Diabetes mellitus
Carbonyl stress Advanced glycation end products AGEs
Carbonyl stress Diabetic hyperglycemia (glycated hemoglobin) Alcohol Renal failure Melanoidins Oxidative stress
Synergism
Down syndrome Trisomy of 21 21q22.11 – SOD gene 150% gene dose Increased oxidative stress Why?
Atherosclerosis
Aging Decreased antioxidative status Lipoperoxidation Lipofuscin – Age pigment Cross-linking of proteins Induction of chronic inflammation Cumulative DNA damage Decreased effectivity of mitochondria
How to slow down the time?
Future outlook New antioxidants Combinatory approaches Antioxidative gene therapy Aminoguanidine and AGE-breakers Clinical studies...