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Zheleznova NN, Kumar V, Kurth T, Cowley AW. Hydrogen peroxide (H 2O 2) mediated activation of mTORC2 increases intracellular Na + concentration in the renal medullary thick ascending limb of Henle. Sci Rep 2021; 11:7300. [PMID: 33790341 PMCID: PMC8012714 DOI: 10.1038/s41598-021-86678-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 03/05/2021] [Indexed: 11/22/2022] Open
Abstract
Hydrogen peroxide (H2O2) production in the renal outer medulla is an important determinant of renal medullary blood flow and blood pressure (BP) salt-sensitivity in Dahl salt-sensitive (SS) rats. The mechanisms and pathways responsible for these actions are poorly understood. Recently, we have discovered that the mTOR complex 2 (mTORC2) plays a critical role in BP salt-sensitivity of SS rats by regulating Na+ homeostasis. PP242, an inhibitor of mTORC1/2 pathways exhibits potent natriuretic actions and completely prevented salt-induced hypertension in SS rats. In the present study, we have found that chronic infusion of H2O2 into the single remaining kidney of Sprague Dawley (SD) rats (3 days) stimulated the functional marker (pAKTSer473/AKT) of mTORC2 activity measured by Western Blot analysis. No changes in mTORC1 activity in OM were observed as determined by pS6Ser235/236/S6. Using fluorescent microscopy and the Na+ sensitive dye Sodium Green, we have shown that H2O2 (100 µM added in the bath) increased intracellular sodium concentration ([Na+]i) in renal medullary thick ascending limbs (mTALs) isolated from SD rats. These responses were almost completely abolished by pretreatment of mTAL with 10 µM PP242, indicating that mTORC1/2 pathways were involved in the H2O2 induced increase of [Na+]i. mTAL cell volume remained unchanged (± 1%) by H2O2 as determined by 3D reconstruction confocal laser scanning microscopy techniques. Consistent with the microscopy data, Western Blot analysis of proteins obtained from freshly isolated mTAL treated with 100 µM H2O2 exhibited increased activity/phosphorylation of AKT (pAKTSer473/AKT) that was inhibited by PP242. This was associated with increased protein activity of the apical membrane cotransporter Na+-K+-2Cl- (NKCC2) and the Na/H exchanger (NHE-3). Na+-K+-ATPase activity was increased as reflected an increase in the ratio of pNa+-K+-ATPaseSer16 to total Na+-K+-ATPase. Overall, the results indicate that H2O2 mediated activation of mTORC2 plays a key role in transducing the observed increases of cytosolic [Na+]i despite associated increases of basolateral pump activity.
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Affiliation(s)
- Nadezhda N Zheleznova
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA.
| | - Vikash Kumar
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA.
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Gupta V, Mahbub P, Nesterenko PN, Paull B. A new 3D printed radial flow-cell for chemiluminescence detection: Application in ion chromatographic determination of hydrogen peroxide in urine and coffee extracts. Anal Chim Acta 2018; 1005:81-92. [PMID: 29389322 DOI: 10.1016/j.aca.2017.12.039] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 11/19/2022]
Abstract
A new polymer flow-cell for chemiluminescence detection (CLD) has been designed and developed by diverging multiple linear channels from a common centre port in a radial arrangement. The fabrication of radial flow-cell by 3D PolyJet printing and fused deposition modeling (FDM) has been evaluated, and compared with a similarly prepared spiral flow-cell design commonly used in chemiluminescence detectors. The radial flow-cell required only 10 h of post-PolyJet print processing time as compared to ca. 360 h long post-PolyJet print processing time required for the spiral flow-cell. Using flow injection analysis, the PolyJet 3D printed radial flow-cell provided an increase in both the signal magnitude and duration, with an average increase in the peak height of 63% and 58%, peak area of 89% and 90%, and peak base width of 41% and 42%, as compared to a coiled-tubing spiral flow-cell and the PolyJet 3D printed spiral flow-cell, respectively. Computational fluid dynamic (CFD) simulations were applied to understand the origin of the higher CLD signal obtained with the radial flow-cell design, indicating higher spatial coverage near the inlet and lower linear velocities in the radial flow-cell. The developed PolyJet 3D printed radial flow-cell was applied in a new ion chromatography chemiluminescence based assay for the detection of H2O2 in urine and coffee extracts.
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Affiliation(s)
- Vipul Gupta
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences, University of Tasmania, Sandy Bay, Hobart 7001, Tasmania, Australia; ARC Centre of Excellence for Electromaterials Science, School of Physical Sciences, University of Tasmania, Sandy Bay, Hobart 7001, Tasmania, Australia
| | - Parvez Mahbub
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences, University of Tasmania, Sandy Bay, Hobart 7001, Tasmania, Australia
| | - Pavel N Nesterenko
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences, University of Tasmania, Sandy Bay, Hobart 7001, Tasmania, Australia
| | - Brett Paull
- Australian Centre for Research on Separation Science (ACROSS), School of Physical Sciences, University of Tasmania, Sandy Bay, Hobart 7001, Tasmania, Australia; ARC Centre of Excellence for Electromaterials Science, School of Physical Sciences, University of Tasmania, Sandy Bay, Hobart 7001, Tasmania, Australia.
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Hydrogen Peroxide and Sodium Transport in the Lung and Kidney. BIOMED RESEARCH INTERNATIONAL 2016; 2016:9512807. [PMID: 27073804 PMCID: PMC4814630 DOI: 10.1155/2016/9512807] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 02/07/2023]
Abstract
Renal and lung epithelial cells are exposed to some significant concentrations of H2O2. In urine it may reach 100 μM, while in the epithelial lining fluid in the lung it is estimated to be in micromolar to tens-micromolar range. Hydrogen peroxide has a stimulatory action on the epithelial sodium channel (ENaC) single-channel activity. It also increases stability of the channel at the membrane and slows down the transcription of the ENaC subunits. The expression and the activity of the channel may be inhibited in some other, likely higher, oxidative states of the cell. This review discusses the role and the origin of H2O2 in the lung and kidney. Concentration-dependent effects of hydrogen peroxide on ENaC and the mechanisms of its action have been summarized. This review also describes outlooks for future investigations linking oxidative stress, epithelial sodium transport, and lung and kidney function.
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Liu X, Han Z, Li F, Gao L, Liang G, Cui H. Highly Chemiluminescent Graphene Oxide Hybrids Bifunctionalized by N-(Aminobutyl)-N-(Ethylisoluminol)/Horseradish Peroxidase and Sensitive Sensing of Hydrogen Peroxide. ACS APPLIED MATERIALS & INTERFACES 2015; 7:18283-18291. [PMID: 26230962 DOI: 10.1021/acsami.5b05325] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
N-aminobutyl-N-ethylisoluminol and horseradish peroxidase bifunctionalized graphene oxide hybrids (ABEI-GO@HRP) were prepared through a facile and green strategy for the first time. The hybrids exhibited excellent chemiluminescence (CL) activity over a wide range of pH from 6.1 to 13.0 when reacted with H2O2, whereas ABEI functionalized GO had no CL emission at neutral pH and showed more than 2 orders of magnitude lower CL intensity than ABEI-GO@HRP at pH 13.0. Such strong CL emission from ABEI-GO@HRP was probably due to that HRP and GO facilitated the formation of O2(•-), - CO4(•2-), HO(•), and π-C═C(•) in the CL reaction, and GO as a reaction interface promoted the electron transfer of the radical-involved reaction. By virtue of ABEI-GO@HRP as a platform, an ultrasensitive, selective, and reagentless CL sensor was developed for H2O2 detection. The CL sensor exhibited a detection limit of 47 fM at physiological pH, which was more than 2 orders of magnitude lower than previously reported methods. This work reveals that bifunctionalization of GO by ABEI and HRP leads to excellent CL feature and enzyme selectivity, which can be used as an ideal platform for developing novel analytical methods.
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Affiliation(s)
- Xiaoying Liu
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China
| | - Zhili Han
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China
| | - Fang Li
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China
| | - Lingfeng Gao
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China
| | - Gaolin Liang
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China
| | - Hua Cui
- CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China
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Lin CS, Lee SH, Huang HS, Chen YS, Ma MC. H2O2 generated by NADPH oxidase 4 contributes to transient receptor potential vanilloid 1 channel-mediated mechanosensation in the rat kidney. Am J Physiol Renal Physiol 2015; 309:F369-76. [PMID: 26136558 DOI: 10.1152/ajprenal.00462.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 06/17/2015] [Indexed: 11/22/2022] Open
Abstract
The presence of NADPH oxidase (Nox) in the kidney, especially Nox4, results in H2O2 production, which regulates Na(+) excretion and urine formation. Redox-sensitive transient receptor potential vanilloid 1 channels (TRPV1s) are distributed in mechanosensory fibers of the renal pelvis and monitor changes in intrapelvic pressure (IPP) during urine formation. The present study tested whether H2O2 derived from Nox4 affects TRPV1 function in renal sensory responses. Perfusion of H2O2 into the renal pelvis dose dependently increased afferent renal nerve activity and substance P (SP) release. These responses were attenuated by cotreatment with catalase or TRPV1 blockers. In single unit recordings, H2O2 activated afferent renal nerve activity in response to rising IPP but not high salt. Western blots revealed that Nox2 (gp91(phox)) and Nox4 are both present in the rat kidney, but Nox4 is abundant in the renal pelvis and originates from dorsal root ganglia. This distribution was associated with expression of the Nox4 regulators p22(phox) and polymerase δ-interacting protein 2. Coimmunoprecipitation experiments showed that IPP increases polymerase δ-interacting protein 2 association with Nox4 or p22(phox) in the renal pelvis. Interestingly, immunofluorescence labeling demonstrated that Nox4 colocalizes with TRPV1 in sensory fibers of the renal pelvis, indicating that H2O2 generated from Nox4 may affect TRPV1 activity. Stepwise increases in IPP and saline loading resulted in H2O2 and SP release, sensory activation, diuresis, and natriuresis. These effects, however, were remarkably attenuated by Nox inhibition. Overall, these results suggest that Nox4-positive fibers liberate H2O2 after mechanostimulation, thereby contributing to a renal sensory nerve-mediated diuretic/natriuretic response.
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Affiliation(s)
- Chian-Shiung Lin
- Department of Surgery, Liou-Ying Hospital, Chi-Mei Medical Center, Tainan Hsien, Taiwan
| | - Shang-Hsing Lee
- Department of Urology, Cardinal Tien Hospital, New Taipei, Taiwan
| | - Ho-Shiang Huang
- Department of Urology, National Cheng Kung University, Tainan, Taiwan
| | - Yih-Sharng Chen
- Department of Cardiovascular Surgery, National Taiwan University Hospital, Taipei, Taiwan; and
| | - Ming-Chieh Ma
- School of Medicine, Fu-Jen Catholic University, New Taipei, Taiwan
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6
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Non–enzymatic amperometric sensing of hydrogen peroxide at a CuS modified electrode for the determination of urine H2O2. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2014.08.051] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Maji SK, Sreejith S, Mandal AK, Ma X, Zhao Y. Immobilizing gold nanoparticles in mesoporous silica covered reduced graphene oxide: a hybrid material for cancer cell detection through hydrogen peroxide sensing. ACS APPLIED MATERIALS & INTERFACES 2014; 6:13648-13656. [PMID: 25046127 DOI: 10.1021/am503110s] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A new kind of two-dimensional (2-D) hybrid material (RGO-PMS@AuNPs), fabricated by the immobilization of ultrasmall gold nanoparticles (AuNPs, ∼3 nm) onto sandwich-like periodic mesopourous silica (PMS) coated reduced graphene oxide (RGO), was employed for both electrocatalytic application and cancer cell detection. The hybrid-based electrode sensor showed attractive electrochemical performance for sensitive and selective nonenzymatic detection of hydrogen peroxide (H2O2) in 0.1 M phosphate buffered saline, with wide linear detection range (0.5 μM to 50 mM), low detection limit (60 nM), and good sensitivity (39.2 μA mM(-1) cm(-2)), and without any interference by common interfering agents. In addition, the sensor exhibited a high capability for glucose sensing and H2O2 detection in human urine. More interestingly, the hybrid was found to be nontoxic, and the electrode sensor could sensitively detect a trace amount of H2O2 in a nanomolar level released from living tumor cells (HeLa and HepG2). Because the hybrid presents significant properties for the detection of bioactive species and certain cancerous cells by the synergistic effect from RGO, PMS, and AuNPs, it could be able to serve as a versatile platform for biosensing, bioanalysis, and biomedical applications.
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Affiliation(s)
- Swarup Kumar Maji
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371, Singapore
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Zor E, Saglam ME, Akin I, Saf AO, Bingol H, Ersoz M. Green synthesis of reduced graphene oxide/nanopolypyrrole composite: characterization and H2O2 determination in urine. RSC Adv 2014. [DOI: 10.1039/c4ra00578c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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9
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Functionalization of carbon buckypaper for the sensitive determination of hydrogen peroxide in human urine. Biosens Bioelectron 2012; 35:302-307. [DOI: 10.1016/j.bios.2012.03.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 03/01/2012] [Accepted: 03/02/2012] [Indexed: 11/22/2022]
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Yuen JWM, Benzie IFF. Hydrogen peroxide in urine as a potential biomarker of whole body oxidative stress. Free Radic Res 2004; 37:1209-13. [PMID: 14703733 DOI: 10.1080/10715760310001616032] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The level of hydrogen peroxide (H2O2) in urine has been suggested as a potential biomarker of whole body oxidative stress, but issues of stability, reproducibility and biological variation have not been investigated to date. In this study, we used a refined protocol, which demonstrated improved sensitivity and precision, to determine the stability of H2O2 in urine, and to measure its concentration in apparently healthy subjects. We also investigated intra-individual variation within and between days. Results showed that H2O2 in urine is stable for up to 48 h at 4 degrees C, however, storage of urine at room temperature was associated with up to 50% increase in H2O2 concentration over a few hours. Total H2O2 in freshly voided urine from 55 healthy, fasting subjects ranged from 0.84 to 5.71 microM, or 90-1164 micromol H2O2/mol creatinine. Intra-individual variation was wide. Even when concentration corrected and collected at the same time of day, 2- to 3-fold variation was seen over 4 consecutive days, and over the course of a single day the creatinine-corrected H2O2 also varied significantly. We suggest that this large biological variation limits the usefulness of urine H2O2 as a biomarker of oxidative stress, the exception being when the effects of disease, therapy or diet induce very large changes in its concentration.
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Affiliation(s)
- J W M Yuen
- Ageing and Health Section, School of Nursing, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, People's Republic of China
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Halliwell B, Whiteman M. Measuring reactive species and oxidative damage in vivo and in cell culture: how should you do it and what do the results mean? Br J Pharmacol 2004; 142:231-55. [PMID: 15155533 PMCID: PMC1574951 DOI: 10.1038/sj.bjp.0705776] [Citation(s) in RCA: 1515] [Impact Index Per Article: 75.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2004] [Revised: 03/08/2004] [Accepted: 03/08/2004] [Indexed: 02/06/2023] Open
Abstract
Free radicals and other reactive species (RS) are thought to play an important role in many human diseases. Establishing their precise role requires the ability to measure them and the oxidative damage that they cause. This article first reviews what is meant by the terms free radical, RS, antioxidant, oxidative damage and oxidative stress. It then critically examines methods used to trap RS, including spin trapping and aromatic hydroxylation, with a particular emphasis on those methods applicable to human studies. Methods used to measure oxidative damage to DNA, lipids and proteins and methods used to detect RS in cell culture, especially the various fluorescent "probes" of RS, are also critically reviewed. The emphasis throughout is on the caution that is needed in applying these methods in view of possible errors and artifacts in interpreting the results.
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Affiliation(s)
- Barry Halliwell
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, MD 7 #03-08, 8 Medical Drive, Singapore 117597, Singapore.
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Hiramoto K, Kida T, Kikugawa K. Increased urinary hydrogen peroxide levels caused by coffee drinking. Biol Pharm Bull 2002; 25:1467-71. [PMID: 12419961 DOI: 10.1248/bpb.25.1467] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments with volunteers in Singapore have demonstrated that coffee drinking increases urinary hydrogen peroxide levels (Long, Halliwell, Free Rad. Res., 32, 463-467 (2000)). We re-examined the effect of coffee drinking of healthy Japanese subjects on urinary hydrogen peroxide levels. A cup of brewed or canned coffee commercially available in Japan generated 120-420 micro mol hydrogen peroxide in incubation in a neutral medium at 37 degrees C for 6 h. The increased levels were higher than those obtained from a cup of green tea extract or a glass of red wine. After the subject drank a cup of coffee, apparent hydrogen peroxide levels (micro mol/g creatinine) in urine collected 1-2 h after coffee drinking increased 3-10-fold compared to the levels before coffee drinking. The increased urinary hydrogen peroxide levels are likely derived mainly from 1,2,4-benzenetriol excreted in urine, because the major component that generates hydrogen peroxide is found to be 1,2,4-benzenetriol, and storing urine collected after coffee drinking increased hydrogen peroxide levels in a time-dependent fashion. Total hydrogen peroxide equivalent levels excreted in 3 h-urine after coffee drinking were estimated to be 0.5-10% that of coffee consumed. A residual amount of hydrogen peroxide may be retained or consumed in human bodies.
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Affiliation(s)
- Kazuyuki Hiramoto
- School of Pharmacy, Tokyo University of Pharmacy and Life Science, Tokyo, Japan
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Abstract
Hydrogen peroxide (H(2)O(2)) is widely regarded as a cytotoxic agent whose levels must be minimized by the action of antioxidant defence enzymes. In fact, H(2)O(2) is poorly reactive in the absence of transition metal ions. Exposure of certain human tissues to H(2)O(2) may be greater than is commonly supposed: substantial amounts of H(2)O(2) can be present in beverages commonly drunk (especially instant coffee), in freshly voided human urine, and in exhaled air. Levels of H(2)O(2) in the human body may be controlled not only by catabolism but also by excretion, and H(2)O(2) could play a role in the regulation of renal function and as an antibacterial agent in the urine. Urinary H(2)O(2) levels are influenced by diet, but under certain conditions might be a valuable biomarker of 'oxidative stress'.
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Affiliation(s)
- B Halliwell
- Department of Biochemistry, Faculty of Medicine, National University of Singapore.
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Long LH, Halliwell B. Coffee drinking increases levels of urinary hydrogen peroxide detected in healthy human volunteers. Free Radic Res 2000; 32:463-7. [PMID: 10766414 DOI: 10.1080/10715760000300461] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Freshly-voided human urine contains significant concentrations of hydrogen peroxide (H2O2). This H2O2 appears to arise in whole or in part by superoxide-dependent autoxidation of urinary biomolecules. Since instant coffee also contains high levels of H2O2, we examined the effect of coffee drinking on urinary levels of H2O2. Studies on healthy human volunteers showed that coffee drinking is rapidly and reproducibly followed by increased levels of H2O2 detectable in the urine for up to 2 h after drinking the coffee. The levels of H2O2 detected in urine suggest that exposure of human tissues to H2O2 may be greater than is commonly supposed. It is possible that H2O2 in urine could act as an antibacterial agent, and that H2O2 is involved in the regulation of glomerular function.
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Affiliation(s)
- L H Long
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, Singapore
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Long LH, Evans PJ, Halliwell B. Hydrogen peroxide in human urine: implications for antioxidant defense and redox regulation. Biochem Biophys Res Commun 1999; 262:605-9. [PMID: 10471371 DOI: 10.1006/bbrc.1999.1263] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The presence of hydrogen peroxide, at levels sometimes exceeding 100 microM, in human urine samples was established by three different assay methods: 2-oxoglutarate decarboxylation and the ferrous oxidation-xylenol orange (FOX) assay and an oxygen electrode. Detected levels of H(2)O(2) were decreased by addition of superoxide dismutase. We conclude that urine contains autooxidizable molecules that, upon exposure to 21% O(2), undergo rapid superoxide-dependent autooxidation reactions to generate H(2)O(2). The exposure of human tissues to hydrogen peroxide may be greater than is commonly supposed, which has implications in relation to the proposed role of this species in cell signaling.
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Affiliation(s)
- L H Long
- Faculty of Medicine, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore
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