Reactive oxygen species (ROS)
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V poslední době dochází k rychlému růstu poznatků o reaktivních kyslíkových a dusíkových sloučeninách (RONS, reactive oxygen and nitrogen species) v klinické medicíně. Jejich významná úloha byla popsána v patogenezi mnoha chorob včetně těch, které značně zatěžují zdravotnické systémy vyspělých států. Výzkumu reaktivních kyslíkových a dusíkových radikálů je proto věnováno velké úsilí. Jedná se o nestabilní částice ochotně reagující s biomolekulami v organismech. Tyto reakce se řetězově propagují a vedou k mnohočetnému poškození buněčných systémů, což se uplatňuje v patogenezi mnoha chorob. Chemickou podstatou těchto částic je přítomnost nespárovaného elektronu v zevním orbitalu. Patří sem také sloučeniny snadno oxidující jiné molekuly. Volné kyslíkové radikály vznikají během fyziologických procesů, jako jsou oxidativní fosforylace v mitochondriích, fagocytóza či při metabolismu purinů. Při nadměrné tvorbě ROS během těchto procesů může dojít k poškození tkáně. Dusíkaté radikály vznikají především při metabolismu oxidu dusnatého, který reguluje mnoho procesů v organismu, rozpřažením jeho syntézy působením např. asymetrického dimetylargininu. Při vzniku radikálů či oxidačně působících látek hrají roli mnohé enzymy jako peroxizomální oxidázy, NAD(P)H oxidáza, xanthinoxidáza, syntáza NO, myeloperoxidáza, lipooxygenáza a mnoho dalších. RONS svůj negativní účinek zprostředkovávají chemickou modifikací DNA, proteinů a lipidů, čímž zasahují do základních biochemických a molekulárně biologických dějů buněk. Proti působení RONS zasahují antioxidační systémy, které se dělí na enzymatické a neenzymatické. RONS se uplatňují v rozvoji mnoha chorobných stavů, z nichž jmenujme aterosklerózu a její kardiovaskulární komplikace, diabetes mellitus, hyperlipidémii, neurodegenerativní či psychiatrická onemocnění.
Vast knowledge has accumulated recently on the role of reactive oxygen and nitrogen species (RONS) in clinical medicine. Strong evidence was disclosed on their important role in the pathogenesis of several diseases. Free radicals have unpaired electron and this is the reason for extreme reactivity causing propagation reactions that lead to the multiple damage to cells. Oxidizing agents belong to the family of reactive species. Reactive oxygen species are produced during biochemical processes such as oxidative phosphorylation, phagocytosis and metabolism of purins. Overproduction of reactive oxygen species can cause the tissue damage. Reactive nitrogen species are produced by inhibition of nitric oxide synthase by the action of asymmetric dimethylarginine. Peroxisomal oxidases, NAD(P) oxidase, xanthinoxidase, nitric oxide synthase, myeloperoxidase and lipooxygenase catalyze biochemical reactions producing reactive oxygen and nitrogen species. Biochemical and molecular processes in cells are negatively influenced by chemical modification of DNA, proteins and lipids caused by the action of reactive oxygen and nitrogen species. Antioxidant metabolites and enzymes work together to stop and to prevent oxidative modification of biomolecules. Reactive oxygen and nitrogen species play an important role in the pathogenesis of many diseases such as atherosclerosis, diabetes, hyperlipidaemia and neurodegenerative diseases.
- Klíčová slova
- neurodegenerativní a psychiatrická onemocnění, antioxidanty, radikál oxidu dusnatého, superoxidový anion, radikály, RONS,
- MeSH
- antioxidancia metabolismus MeSH
- ateroskleróza metabolismus MeSH
- diabetes mellitus metabolismus MeSH
- duševní poruchy metabolismus MeSH
- lidé MeSH
- neurodegenerativní nemoci metabolismus MeSH
- reaktivní formy dusíku chemie metabolismus MeSH
- reaktivní formy kyslíku chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Reactive oxygen species (ROS) are small reactive molecules produced by cellular metabolism and regulate various physiological and pathological functions. Many studies have shown that ROS plays an essential role in the proliferation and inhibition of tumor cells. Different concentrations of ROS can have a "double-edged sword" effect on the occurrence and development of tumors. A certain concentration of ROS can activate growth-promoting signals, enhance the proliferation and invasion of tumor cells, and cause damage to biomacromolecules such as proteins and nucleic acids. However, ROS can enhance the body's antitumor signal at higher levels by initiating oxidative stress-induced apoptosis and autophagy in tumor cells. This review analyzes ROS's unique bidirectional regulation mechanism on tumor cells, focusing on the key signaling pathways and regulatory factors that ROS affect the occurrence and development of tumors and providing ideas for an in-depth understanding of the mechanism of ROS action and its clinical application.
- MeSH
- antioxidancia metabolismus MeSH
- karcinogeneze * MeSH
- lidé MeSH
- nádory * metabolismus MeSH
- oxidační stres fyziologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
AIMS: Excessive production of reactive oxygen species (ROS) in semen has been linked to male infertility. Main sources of ROS in male genital tract are immature and/or damaged spermatozoa and a subpopulation of leukocytes known as polymorphonuclear neutrophils (PMN). METHODS: Study group included male partners of infertile couples, 67 normospermic males (group B) and 98 males with sperm abnormalities in one or more parameters (group C), 36 fertile volunteers (group A) served as controls. Sperm parameters were determined according to WHO guidelines. The ROS production was measured by chemiluminiscence in sperm suspension in phosphate buffered saline. RESULTS: All fertile volunteers in the control group had seminal PMN concentrations below 0.5x10(6)/ml. Therefore study subjects, 67 normospermic and 98 men with sperm abnormalities, were further subdivided into two subgroups of PMN concentrations: (1) < 0.5x10(6)/ml and (2) 0.5 to 1.0x10(6)/ml. The ROS production in individuals varied greatly from 1.0x10(2) to 1.7 x10(7) RLU/min per 20x10(6) spermatozoa. The ROS production in both subgroups of normospermic men and the subgroup (1) of men with sperm abnormalities was not different from the ROS production in fertile controls. The ROS production in the subgroup (2) with sperm abnormalities was significantly higher than in controls (P = 0.00004). CONCLUSIONS: Our findings suggest that the contribution of PMN to the ROS production in semen is negligible only up to a concentration of 0.5x10(6)/ml. This suggests that the current WHO Guidelines threshold of 1.0x10(6) PMN per ml of semen is too high and might be re-evaluated.
One of the universal traits of microorganisms is their ability to form multicellular structures, the cells of which differentiate and communicate via various signaling molecules. Reactive oxygen species (ROS), and hydrogen peroxide in particular, have recently become well-established signaling molecules in higher eukaryotes, but still little is known about the regulatory functions of ROS in microbial structures. Here we summarize current knowledge on the possible roles of ROS during the development of colonies and biofilms, representatives of microbial multicellularity. In Saccharomyces cerevisiae colonies, ROS are predicted to participate in regulatory events involved in the induction of ammonia signaling and later on in programmed cell death in the colony center. While the latter process seems to be induced by the total ROS, the former event is likely to be regulated by ROS-homeostasis, possibly H(2)O(2)-homeostasis between the cytosol and mitochondria. In Candida albicans biofilms, the predicted signaling role of ROS is linked with quorum sensing molecule farnesol that significantly affects biofilm formation. In bacterial biofilms, ROS induce genetic variability, promote cell death in specific biofilm regions, and possibly regulate biofilm development. Thus, the number of examples suggesting ROS as signaling molecules and effectors in the development of microbial multicellularity is rapidly increasing.
The catalytic role of iron in the Haber-Weiss chemistry, which results in propagation of damaging reactive oxygen species (ROS), is well established. In this review, we attempt to summarize the recent evidence showing the reverse: That reactive oxygen and nitrogen species can significantly affect iron metabolism. Their interaction with iron-regulatory proteins (IRPs) seems to be one of the essential mechanisms of influencing iron homeostasis. Iron depletion is known to provoke normal iron uptake via IRPs, superoxide and hydrogen peroxide are supposed to cause unnecessary iron uptake by similar mechanism. Furthermore, ROS are able to release iron from iron-containing molecules. On the contrary, nitric oxide (NO) appears to be involved in cellular defense against the iron-mediated ROS generation probably mainly by inducing iron removal from cells. In addition, NO may attenuate the effect of superoxide by mutual reaction, although the reaction product-peroxynitrite-is capable to produce highly reactive hydroxyl radicals.
Abstract Reactive oxygen species (ROS) and reactive nitrogen species have generally been considered as being highly reactive and cytotoxic molecules. Besides their noxious effects, ROS participate in physiological processes in a carefully regulated manner. By way of example, microbicidal ROS are produced in professional phagocytes, ROS function as short-lived messengers having a role in signal transduction and, among other processes, participate in the synthesis of the iodothyronine hormones, reproduction, apoptosis and necrosis. Because of their ability to mediate a crosstalk between key molecules, their role might be dual (at least in some cases). The levels of ROS increase from a certain age, being associated with various diseases typical of senescence. The aim of this review is to summarize the recent findings on the physiological role of ROS. Other issues addressed are an increase in ROS levels during ageing, and the possibility of the physiological nature of this process.
- MeSH
- lidé MeSH
- reaktivní formy dusíku fyziologie metabolismus MeSH
- signální transdukce fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
A physiological level of oxygen/nitrogen free radicals and non-radical reactive species (collectively known as ROS/RNS) is termed oxidative eustress or "good stress" and is characterized by low to mild levels of oxidants involved in the regulation of various biochemical transformations such as carboxylation, hydroxylation, peroxidation, or modulation of signal transduction pathways such as Nuclear factor-κB (NF-κB), Mitogen-activated protein kinase (MAPK) cascade, phosphoinositide-3-kinase, nuclear factor erythroid 2-related factor 2 (Nrf2) and other processes. Increased levels of ROS/RNS, generated from both endogenous (mitochondria, NADPH oxidases) and/or exogenous sources (radiation, certain drugs, foods, cigarette smoking, pollution) result in a harmful condition termed oxidative stress ("bad stress"). Although it is widely accepted, that many chronic diseases are multifactorial in origin, they share oxidative stress as a common denominator. Here we review the importance of oxidative stress and the mechanisms through which oxidative stress contributes to the pathological states of an organism. Attention is focused on the chemistry of ROS and RNS (e.g. superoxide radical, hydrogen peroxide, hydroxyl radicals, peroxyl radicals, nitric oxide, peroxynitrite), and their role in oxidative damage of DNA, proteins, and membrane lipids. Quantitative and qualitative assessment of oxidative stress biomarkers is also discussed. Oxidative stress contributes to the pathology of cancer, cardiovascular diseases, diabetes, neurological disorders (Alzheimer's and Parkinson's diseases, Down syndrome), psychiatric diseases (depression, schizophrenia, bipolar disorder), renal disease, lung disease (chronic pulmonary obstruction, lung cancer), and aging. The concerted action of antioxidants to ameliorate the harmful effect of oxidative stress is achieved by antioxidant enzymes (Superoxide dismutases-SODs, catalase, glutathione peroxidase-GPx), and small molecular weight antioxidants (vitamins C and E, flavonoids, carotenoids, melatonin, ergothioneine, and others). Perhaps one of the most effective low molecular weight antioxidants is vitamin E, the first line of defense against the peroxidation of lipids. A promising approach appears to be the use of certain antioxidants (e.g. flavonoids), showing weak prooxidant properties that may boost cellular antioxidant systems and thus act as preventive anticancer agents. Redox metal-based enzyme mimetic compounds as potential pharmaceutical interventions and sirtuins as promising therapeutic targets for age-related diseases and anti-aging strategies are discussed.
- MeSH
- antioxidancia * MeSH
- chronická nemoc MeSH
- lidé MeSH
- oxidační stres * MeSH
- reaktivní formy kyslíku MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Cíl: Sledování incidence bakteriospermie, rodového a druhového zastoupení mikroorganizmů a produkce reaktivních kyslíkových částic (ROS) v ejakulátu mužů z neplodných párů v porovnání s fertilními dobrovolníky. Soubor pacientů a metody. Muži z párů léčených pro neplodnost byli rozděleni podle WHO parametrů spermiogramu na normospermiky (skupina A, n = 65) a muže s abnormálním spermiogramem (skupina B, n = 116). Kontrolní skupinu tvořilo 44 dobrovolníků s prokázanou fertilitou (skupina C). Aerobní kultivací bylo prokázáno rodové a druhové zastoupení přítomných mikroorganizmů. Produkce ROS byla vyšetřována chemiluminiscenční metodou. Statistické hodnocení bylo provedeno pomocí Mann -Whitneyova testu. Výsledky. Incidence bakteriospermie mezi skupinami A, B a C (69 %, 74 % a 66 % ) nebyla statisticky významná, převládaly kmeny StaphyJococcus species a Streptococcus species. Signifikantní rozdíl však jsme pozorovali mezi výskytem kmenů Escheríchia coli mezi muži z neplodných párů (skupina A = 11,1 %, B = 9,3 %) a muži fertilními (skupina C = 3,2 %). Neprokázali jsme statisticky signifikantní rozdíly mezi produkcí ROS v kultivačně pozitivních a kultivačně negativních ejakulátech v žádné ze sledovaných skupin. Závěr. Ve všech sledovaných skupinách byla incidence bakteriospermie stejně jako produkce ROS v ejakulátu obdobná. V druhovém zastoupení převažovaly kmeny Staphylococcus species a Streptococcus species ve všech skupinách. Ve vzorcích z neplodných párů bya prokázána signifikantně vyšší přítomnost kmenů Escheríchia coh oproti kontrolní skupině. V produkci ROS nebyly prokázány rozdíly mezi kultivačně pozitivními a negativními vzorky v jednodivých skupinách.
Objective: To estimate the incidence of bacteriospermia, the representation of specific micro-organisms and the generation of reactive oxygen species (ROS) in the semen of males from infertile couples in comparison with the semen of fertile volunteers. Material and Methods: Males from infertile couples were divided according to WHO criteria of their spermiogram results into those with normospermia (Group A, n = 65) and those with semen abnormalities (Group B, n = 116). The control group consisted of 44 fertile volunteers (Group C, n = 44). Aerobic culture was performed to ascertain the genus and species of the present microorganisms. ROS production was estimated by the chemiluminescence method. Statistical analysis was performed using the Mann-Whitney test. Results: The incidence of positive cultures in the semen between Groups A, B and C (69 %, 74 % and 66 %, respectively) did not differ significantly, with Staphylococcus and Streptococcus species being most frequently identified. A significant difference was found only between the occurence of microorganism Escherichia coU in the groups A, B and C (11.1 %, 9.3 % and 3.2 %). There were no statistically significant differences between ROS production in semen with positive or negative culture in any of the studied groups. Conclusions: In all the studied groups, the incidence of bacteriospermia as well as ROS production in the semen were similar. Staphylococcus and Streptococcus species were found in all groups. A significantly higher frequency of Escherichia coh in the semen samples of males from infertile couples in comparison with those from fertile volunteers was observed. No differences in ROS production in semen samples with positive and negative culture results were found in any of the studied groups.
- MeSH
- aerobní bakterie izolace a purifikace klasifikace MeSH
- analýza spermatu klasifikace MeSH
- C-reaktivní protein analýza MeSH
- financování organizované MeSH
- incidence MeSH
- lidé MeSH
- mužská infertilita diagnóza etiologie mikrobiologie MeSH
- reaktivní formy kyslíku analýza MeSH
- sperma chemie mikrobiologie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
Pulmonary hypertension resulting from chronic hypoxia is at least partly caused by the increased production of reactive oxygen species (ROS). The goal of the presented study was to investigate the dynamics and the site of production of ROS during chronic hypoxia. In our study Wistar rats were kept for 1, 4 and 21 days in an isobaric hypoxic chamber (FiO2=0.1), while controls stayed in normoxia. We compared NO production in expired air, plasma and perfusate drained from isolated rat lungs and measured superoxide concentration in the perfusate. We also detected the presence of superoxide products (hydrogen peroxide and peroxynitrite) and the level of ROS-induced damage expressed as the concentration of lipid peroxydation end products. We found that the production and release of ROS and NO during early phase of chronic hypoxia has specific timing and differs in various compartments, suggesting the crucial role of ROS interaction for development of hypoxic pulmonary hypertension.
- MeSH
- arteria pulmonalis metabolismus MeSH
- hypoxie komplikace metabolismus MeSH
- krysa rodu rattus MeSH
- kyselina peroxydusitá metabolismus MeSH
- oxid dusnatý biosyntéza krev MeSH
- peroxid vodíku metabolismus MeSH
- plicní hypertenze etiologie MeSH
- potkani Wistar MeSH
- reaktivní formy kyslíku metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
Ultra-weak photon emission originates from the relaxation of electronically excited species formed in the biological systems such as microorganisms, plants and animals including humans. Electronically excited species are formed during the oxidative metabolic processes and the oxidative stress reactions that are associated with the production of reactive oxygen species (ROS). The review attempts to overview experimental evidence on the involvement of superoxide anion radical, hydrogen peroxide, hydroxyl radical and singlet oxygen in both the spontaneous and the stress-induced ultra-weak photon emission. The oxidation of biomolecules comprising either the hydrogen abstraction by superoxide anion and hydroxyl radicals or the cycloaddition of singlet oxygen initiate a cascade of oxidative reactions that lead to the formation of electronically excited species such as triplet excited carbonyl, excited pigments and singlet oxygen. The photon emission of these electronically excited species is in the following regions of the spectrum (1) triplet excited carbonyl in the near UVA and blue-green areas (350-550nm), (2) singlet and triplet excited pigments in the green-red (550-750nm) and red-near IR (750-1000nm) areas, respectively and (3) singlet oxygen in the red (634 and 703nm) and near IR (1270nm) areas. The understanding of the role of ROS in photon emission allows us to use the spontaneous and stress-induced ultra-weak photon emission as a non-invasive tool for monitoring of the oxidative metabolic processes and the oxidative stress reactions in biological systems in vivo, respectively.
- MeSH
- elektrony MeSH
- fotobiologie metody MeSH
- fotony * MeSH
- lidé MeSH
- oxidace-redukce MeSH
- reaktivní formy kyslíku metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
