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Table of Contents

    Topic review

    Oxidative Stress Biomarkers

    Subjects: Biology
    View times: 9
    Submitted by: Katarzyna Kotfis


    Oxidative stress biomarkers can be used to detect oxidative damages occurring concomitantly in many cellular structures, which may cause a deterioration of function, including apoptosis and necrosis. There is an intimate relationship between oxidative stress, inflammation, and functional impairment, resulting in various diseases affecting the entire human body.

    1. Introduction

    Reactive oxygen species are compounds that are difficult to measure when assessing oxidative stress, primarily due to the very short half-life, so they hardly play the role of biomarkers. However, if ROS combines with a particular biological molecule, it leaves a unique chemical “fingerprint”. Biomarkers obtained that way can be used to evaluate oxidative damage or the effects of antioxidants, including therapeutic agents. The core criterion for the biomarker is its role in the prediction of the later development of disease. Moreover, important technical criteria of a biomarker are it should detect a major part of total ongoing oxidative damage in vivo, should provide coherent laboratory assays, results should not vary under the same conditions, should be stable during storage, must employ chemically robust measurement technology, and must not be confounded by diet [1]. There is no ideal biomarker, yet many provide sufficient accuracy. ROS, as highly reactive substances, interact with the environment in vivo, involving and stimulating various endogenous mechanisms as well as react with numerous molecules, leaving a mentioned fingerprint, which becomes the point of interest in specific evaluations. ROS, reactions, and essential antioxidants were presented in Figure 1.

    Figure 1. Basics of intracellular antioxidant mechanisms and nuclear signaling. Legend: CAT—catalase, GPx—glutathione peroxidase, GR—glutathione reductase, GST—glutathione S-transferases, GSH—reduced glutathione, GSSG—oxidized glutathione, Q—coenzyme Q10, GS—glutathione synthetase, HO·—hydroxyl radical, H2O2—hydrogen peroxide, L·—alkyl radical, LO·—alkoxy radical, LOO·—peroxy radical, HOCl—hypochlorous acid, NO—nitric oxide, NOS—nitric oxide synthase, NQO1—NADPH-quinone oxidoreductase-1, O2—molecular oxygen, O2•—superoxide, SOD—superoxide dismutase, AGE—advanced glycation end products, NF-κB—nuclear factor kappa-light-chain-enhancer of activated B cells, AP1—activator protein 1, Nrf2—nuclear factor-erythroid 2-related factor 2, HSF1—heat shock factor 1, PDX1—insulin promoter factor 1, FoxO—forkhead transcription factor O.

    2. Oxidative Stress Biomarkers

    2.1. Endogenous Antioxidants

    ATP cell production is inherently connected with oxidation, reduction, and ROS generation. External factors involve microbial infections, xenobiotics, diet toxins, radiation, environmental pollution, and others. Living organisms developed specific defense systems against the deleterious action of free radicals. The most important mechanisms are intracellular; however, they act with both extracellular and dietary exogenous antioxidants. Endogenous antioxidants are divided into two groups: protein (with enzymatic activity) and non-protein. Protein ones are the first line of defense, with three the most important: CAT, SOD, and GPx. PubMed search formula for general interest was determined by: {(“biomarker”[Title/Abstract]) AND (oxidative stress)}. Research interest in the field of transplantation, as a Medical Subject Headings, was determined by search formula: {(“biomarker” [Title/Abstract]) AND (transplantation)} (Table 1).
    Table 1. Endogenous antioxidants—description and research interest.
    Biomarker Description General Transplantation
    tetramer, enzyme, biomarker, catalyzes the decomposition of hydrogen peroxide to water and oxygen, has one of the highest turnover numbers of all enzymes, first noticed in 1818 Ijms 22 08010 i025
    Ijms 22 08010 i026
    enzyme, biomarker, metalloprotein connected in humans with Zn/Cu or Mn, discovered in 1968 Ijms 22 08010 i027
    Ijms 22 08010 i028
    selenium-containing enzyme family, several isozymes are encoded by different genes, biomarker, the protective system depends heavily on the presence of selenium, discovered in 1957 Ijms 22 08010 i029
    Ijms 22 08010 i030
    family of metabolic isoenzymes, biomarker, catalyze the conjugation of the reduced form of glutathione (GSH) to xenobiotic substrates, nomenclature first proposed in 1992 Ijms 22 08010 i031
    Ijms 22 08010 i032
    homodimer disulfide oxidoreductase enzyme encoded by the GSR gene, biomarker, catalyzes GSSH and regenerates it to GSH, involves NADPH and FAD binding domains, first purified in 1955 Ijms 22 08010 i033
    Ijms 22 08010 i034
    heme oxygenase 1
    an enzyme, mediates the first step of heme catabolism, cleaves heme to biliverdin, carbon monoxide, and ferrous iron, encoded by HMOX1 gene induced in oxidative stress and inflammation, first characterized in 1962 Ijms 22 08010 i035
    Ijms 22 08010 i036
    NADPH-quinone oxidoreductase-1
    protein homodimer, detoxifying enzyme, present in cytosol, performs a two-electron reduction of quinones to hydroquinones and of other redox dyes without the formation of ROS, Ijms 22 08010 i037
    Ijms 22 08010 i038
    L-γ-glutamyl-L-cysteinyl-glycine, non-enzymatic, biomarker, reduced form (GSH) and glutathione disulfide (GSSG)—primary redox couple in animal cells Ijms 22 08010 i039
    Ijms 22 08010 i040
    coenzyme Q
    benzoquinone derivate, localized in the mitochondrial respiratory chain and other internal membranes, coenzyme, first isolate was in 1950 in the lining of a horse’s gut Ijms 22 08010 i041
    Ijms 22 08010 i042
    α-lipoic acid
    delivers antioxidant activity in nonpolar and polar mediums, effective in recharging enzymes in the mitochondria, might counteract NF-κB activation Ijms 22 08010 i043
    Ijms 22 08010 i044
    product of heme degradation works as an antioxidant in cycle BR-biliverdin, relevantly documented in 1827 Ijms 22 08010 i045
    Ijms 22 08010 i046
    ferritin intracellular globular iron-binding protein, small amounts are secreted into the serum, prevents ROS generation via the Fenton reaction by binding iron Ijms 22 08010 i047
    Ijms 22 08010 i048

    2.2. Lipid Peroxidation (LPO)

    Lipids can be oxidized, chlorinated, and nitrated by a range of RS, excluding H2O2, NO, or O2•−, which are unreactive with lipids. Lipid peroxidation is a complex process, and a wide range of products is formed in variable amounts.
    It is the most widely known biological free radical chain (FRC) reaction. The oxidation of unsaturated fatty acids or other lipids results in products, which are peroxides of these compounds. Note that ROS does not initiate peroxidation. Their presence only intensifies the process. Peroxidation reaction, like every FRC, can be divided into three stages:
    1. Initiation: Creation of fatty acid radical. ROS which initiates this reaction in living cells are hydroxyl (HO·), peroxy (LOO·), alkoxy (LO·), and alkyl (L·), as well as O3, SO2, and NO2. The separation of hydrogen leads to the formation of an alkyl radical. LH →L + H2O.
    2. Prolongation: Unstable fatty acid radicals easily react with molecular oxygen (O2), forming peroxides, which are also unstable and react with more fatty acid molecules, creating more radicals. The reaction runs in a cycle: L + O2→LOO LOO + LH →LOOH + L.
    3. Termination: Growing number of free radicals increases the probability of collision between them, which ends the process: L + L →L–L, LOO + LOO →L=O + LOH + O2, LOO + L →L=O + LOH. Termination reaction results in products such as dimers of fatty acids, hydroxy acids, and oxoacids.
    In Table 2, we summarized biomarkers of lipid peroxidation (BLP) with histograms of research interest. General interest was determined by search formula: {(“biomarker”[Title/Abstract]) AND (oxidative stress)}. Research interest in the field of transplantation, as a Medical Subject Headings, was determined by search formula: {(“biomarker”[Title/Abstract]) AND (transplantation)}. In the last decade, there was a significant growing interest in MDA, with proportional interest in transplantation. However much less expressed, two other “popular” were TBARS and 4-HNE with similar reflection in transplantation. Surprisingly there was a little interest in isoprostanes in transplantation.
    Table 2. Biomarkers of lipid peroxidation—description and research interest.
    Biomarker Description General Transplantation
    the oldest and one of the most widely used nonspecific by-products of lipid peroxidation, reacts with thiobarbituric acid (TBA), forming a pink chromogen (TBARS) measured at 532–535 nm Ijms 22 08010 i049
    Ijms 22 08010 i050
    CH2(CHO)2, colorless liquid, highly reactive, a product of LPO of polyunsaturated fatty acids, form covalent protein adducts referred to as advanced lipoxidation end-products (ALE), in analogy to advanced glycation end-products (AGE) Ijms 22 08010 i051
    Ijms 22 08010 i052
    α,β-unsaturated hydroxyalkenal, produced by lipid peroxidation (arachidonic or linoleic groups) in cells in higher quantities during oxidative stress, possible role in cell signal transduction, first reported in 1991 [2], they can also come from omega-3 fatty acids Ijms 22 08010 i053
    Ijms 22 08010 i054
    the simplest unsaturated aldehyde, named and characterized in 1839, electrophilic, reactive and toxic, contact herbicide to weeds, present in tobacco smoke increases the risk of cancer, produced during cyclophosphamide treatment Ijms 22 08010 i055
    Ijms 22 08010 i056
    F2-isoprostanes prostaglandin-like compounds formed in vivo from the free radical-catalyzed peroxidation of arachidonic acid, discovered in 1990, Ijms 22 08010 i057
    Ijms 22 08010 i058
    F4-isoprostanes prostaglandin-like compounds formed in vivo from the free radical-catalyzed peroxidation of docosahexaenoic acid, potent biological activity as anti-inflammatory mediators Ijms 22 08010 i059
    CH3CH, representative carcinogenic aldehyde formed endogenously through lipid peroxidation, CRA is a highly reactive aldehyde and reacts with a lysine residue in the protein, reaction with CRA and lysine residue leads to the formation of numerous numbers of adducts Ijms 22 08010 i060
    Ijms 22 08010 i061
    oxygenated α,β-unsaturated aldehyde, other coming from omega-3 fatty acids: 4-oxo-trans-2-nonenal, 4-hydroperoxy-trans-2-nonenal, and 4,5-epoxy-trans-2-decenal Ijms 22 08010 i062
    Ijms 22 08010 i063
    toxic oxysterol, produced from oxidized cholesterol, induces: NOX, pro-inflammatory cytokines and TNF-α Ijms 22 08010 i064
    Ijms 22 08010 i065

    2.3. Protein Oxidation

    Biomarkers of proteins peroxidation were presented in Table 3.
    Table 3. Biomarkers of proteins peroxidation—description and research interest.
    Biomarker Description General Transplantation
    product of the reaction of hypobromous acid (HOBr) from hydrogen peroxide (H2O2) and bromide ion (Br), detected by anti-dibromo-tyrosine [DiBrY], mAb (3A5) JAI-MBY-020P Ijms 22 08010 i066
    1951, 1989, 1995, 1999, 2018
    biphenyl compound comprising two tyrosine residues linked at carbon-3 of their benzene rings Ijms 22 08010 i067
    2001, 2005, 2010, 2012, 2020(2)
    abnormal tyrosine isomers, derive from oxidation of the benzyl ring of the phenylalanine by hydroxyl radical, adversely affect cells and tissues Ijms 22 08010 i068
    2003, 2007, 2008, 2012
    specific marker of attack of peroxynitrite (ONOO) upon proteins, measured by immunostaining, HPLC, and MS in human tissues Ijms 22 08010 i069
    Ijms 22 08010 i070
    protein carbonyls measurement of protein CO groups after their derivatization with DNPH is the most widely utilized measure of protein oxidation Ijms 22 08010 i071
    Ijms 22 08010 i072

    2.4. Nucleic Acid Oxidation

    Oxidative DNA damage, mostly due to the hydroxyl radical, generates a huge range of base and sugar modification products [3]. They can be measured by HPLC, gas chromatography–mass spectrometry (GC–MS), liquid chromatography–mass spectrometry (LC–MS), and antibody-based techniques, but none of these have been established as a gold standard [1]. It is estimated that each cell under normal conditions is the target of several thousand attacks on its DNA every day. Free radicals attacking DNA purines, pyrimidines, and deoxyribose create initial products, which undergo further transformations. Damage to DNA by free radicals occurs much less frequently than oxygen damage to proteins and lipids. However, the consequences are more serious due to mutagenic or immunogenic changes. One of the major products of DNA oxidation is 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-oxoguanine (8-oxo-Gua) [4].
    Biomarkers of nucleic acids peroxidation were presented in Table 4.
    Table 4. Biomarkers of nucleic acids peroxidation—description and research interest.
    Biomarker Description General Transplantation
    oxidized derivative of deoxyguanosine, major products of DNA oxidation, increased levels are found during carcinogenesis, increases with age, linked to the enzyme OGG1 and transcription factor NFκB Ijms 22 08010 i073
    Ijms 22 08010 i074
    one of the most common DNA lesions resulting from reactive oxygen species, modifying guanine, and can result in a mismatched pairing with adenine resulting in G to T and C to A → mutation Ijms 22 08010 i075

    3. Conclusions

    Oxidative stress is a complex phenomenon resulting from the imbalance of cell homeostasis, leading to oxidative damage. It plays a vital role in the pathogenesis of many diseases. Oxidative stress is directly caused by reactive species, mainly ROS. Some of them contain unpaired electrons—free radicals, and others do not, but all of them are very reactive and cause the peroxidation of various molecules. Damage to so many cellular structures can result in the deterioration of function, including apoptosis and necrosis. Oxidative damage leaves a mark, which can be detectible by specific methodology regarding affected molecules. Those substances become the biomarkers of oxidative stress due to their ability to represent the intensity of biochemical changes accurately. The group of biomarkers, in general, comprises internal compounds related to cell physiology as well as end products of peroxidation reactions. Maintaining the cell homeostasis and redox state is a matter of competing chemical reactions and a very complex cellular and nuclear signaling mechanism. The cell can react to the environment and redistribute the energy and resources to overcome certain adverse events as oxidative stress. Oxidative damage, stress, and ROS are still intensively exploited research subjects, especially kidney disease and renal transplantation. However, the modern approach regards mainly signaling pathways and cell internal regulation; therefore, further research is necessary to translate the biochemical correlations into clinical practice and organ protection. With time, adequate interventions and solutions at the cellular level will lead to outcome improvement after organ transplantation.

    The entry is from 10.3390/ijms22158010


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