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Croce AC, Ferrigno A, Berardo C, Bottiroli G, Vairetti M, Di Pasqua LG. Spectrofluorometric Analysis of Autofluorescing Components of Crude Serum from a Rat Liver Model of Ischemia and Reperfusion. Molecules 2020; 25:molecules25061327. [PMID: 32183261 PMCID: PMC7144569 DOI: 10.3390/molecules25061327] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 12/20/2022] Open
Abstract
Autofluorescence (AF) of crude serum was investigated with reference to the potential of its intrinsic AF biomarkers for the noninvasive diagnosis of liver injury. Spectral parameters of pure compounds representing retinol (vitamin A) and fluorescing free fatty acids were characterized by spectrofluorometry, to assess spectral parameters for the subsequent AF analysis of serum, collected from rats undergoing liver ischemia/reperfusion (I/R). Differences in AF spectral profiles detected between control and I/R were due to the increase in the AF components representing fatty acids in I/R serum samples. No significant changes occurred for retinol levels, consistently with the literature reporting that constant retinol levels are commonly observed in the blood, except for malnutrition or chronic severe liver disease. Conversely, fatty acids, in particular arachidonic and linoleic acid and their derivatives, act as modulating agents in inflammation, representing both a protective and damaging response to stress stimuli. The biometabolic and pathophysiological meaning of serum components and the possibility of their direct detection by AF spectrofluorometry open up interesting perspectives for the development of AF serum analysis, as a direct, cost effective, supportive tool to assess liver injury and related systemic metabolic alterations, for applications in experimental biomedicine and foreseen translation to the clinics.
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Affiliation(s)
- Anna C. Croce
- Institute of Molecular Genetics, Italian National Research Council (CNR), Via Abbiategrasso 207, I-27100 Pavia, Italy;
- Department of Biology & Biotechnology, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy
- Correspondence: ; Tel.: +39-0382-986-428
| | - Andrea Ferrigno
- Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy; (A.F.); (C.B.); (M.V.); (L.G.D.P.)
| | - Clarissa Berardo
- Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy; (A.F.); (C.B.); (M.V.); (L.G.D.P.)
| | - Giovanni Bottiroli
- Institute of Molecular Genetics, Italian National Research Council (CNR), Via Abbiategrasso 207, I-27100 Pavia, Italy;
- Department of Biology & Biotechnology, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy
| | - Mariapia Vairetti
- Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy; (A.F.); (C.B.); (M.V.); (L.G.D.P.)
| | - Laura G. Di Pasqua
- Department of Internal Medicine and Therapeutics, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy; (A.F.); (C.B.); (M.V.); (L.G.D.P.)
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Erpicum P, Rowart P, Defraigne JO, Krzesinski JM, Jouret F. What we need to know about lipid-associated injury in case of renal ischemia-reperfusion. Am J Physiol Renal Physiol 2018; 315:F1714-F1719. [PMID: 30332314 DOI: 10.1152/ajprenal.00322.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Renal segmental metabolism is reflected by the complex distribution of the main energy pathways along the nephron, with fatty acid oxidation preferentially used in the cortex area. Ischemia/reperfusion injury (IRI) is due to the restriction of renal blood flow, rapidly leading to a metabolic switch toward anaerobic conditions. Subsequent unbalance between energy demand and oxygen/nutrient delivery compromises kidney cell functions, resulting in a complex inflammatory cascade including the production of reactive oxygen species (ROS). Renal IRI especially involves lipid accumulation. Lipid peroxidation is one of the major events of ROS-associated tissue injury. Here, we briefly review the current knowledge of renal cell lipid metabolism in normal and ischemic conditions. Next, we focus on renal lipid-associated injury, with emphasis on its mechanisms and consequences during the course of IRI. Finally, we discuss preclinical observations aiming at preventing and/or attenuating lipid-associated IRI.
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Affiliation(s)
- Pauline Erpicum
- Division of Nephrology, University of Liège Academic Hospital , Liège , Belgium.,Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège , Liège , Belgium
| | - Pascal Rowart
- Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège , Liège , Belgium
| | - Jean-Olivier Defraigne
- Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège , Liège , Belgium.,Division of Cardio-Thoracic Surgery, University of Liège Academic Hospital , Liège , Belgium
| | | | - François Jouret
- Division of Nephrology, University of Liège Academic Hospital , Liège , Belgium.,Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège , Liège , Belgium
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Croce AC, Ferrigno A, Bottiroli G, Vairetti M. Autofluorescence-based optical biopsy: An effective diagnostic tool in hepatology. Liver Int 2018; 38:1160-1174. [PMID: 29624848 DOI: 10.1111/liv.13753] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/27/2018] [Indexed: 12/15/2022]
Abstract
Autofluorescence emission of liver tissue depends on the presence of endogenous biomolecules able to fluoresce under suitable light excitation. Overall autofluorescence emission contains much information of diagnostic value because it is the sum of individual autofluorescence contributions from fluorophores involved in metabolism, for example, NAD(P)H, flavins, lipofuscins, retinoids, porphyrins, bilirubin and lipids, or in structural architecture, for example, fibrous proteins, in close relationship with normal, altered or diseased conditions of the liver. Since the 1950s, hepatocytes and liver have been historical models to study NAD(P)H and flavins as in situ, real-time autofluorescence biomarkers of energy metabolism and redox state. Later investigations designed to monitor organ responses to ischaemia/reperfusion were able to predict the risk of dysfunction in surgery and transplantation or support the development of procedures to ameliorate the liver outcome. Subsequently, fluorescent fatty acids, lipofuscin-like lipopigments and collagen were characterized as optical biomarkers of liver steatosis, oxidative stress damage, fibrosis and disease progression. Currently, serum AF is being investigated to improve non-invasive optical diagnosis of liver disease. Validation of endogenous fluorophores and in situ discrimination of cancerous from non-cancerous tissue belong to the few studies on liver in human subjects. These reports along with other optical techniques and the huge work performed on animal models suggest many optically based applications in hepatology. Optical diagnosis is currently offering beneficial outcomes in clinical fields ranging from the respiratory and gastrointestinal tracts, to dermatology and ophthalmology. Accordingly, this review aims to promote an effective bench to bedside transfer in hepatology.
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Affiliation(s)
- Anna Cleta Croce
- Institute of Molecular Genetics, Italian National Research Council (CNR), Pavia, Italy.,Department of Biology & Biotechnology, University of Pavia, Pavia, Italy
| | - Andrea Ferrigno
- Internal Medicine and Therapy Department, University of Pavia, Pavia, Italy
| | - Giovanni Bottiroli
- Institute of Molecular Genetics, Italian National Research Council (CNR), Pavia, Italy.,Department of Biology & Biotechnology, University of Pavia, Pavia, Italy
| | - Mariapia Vairetti
- Internal Medicine and Therapy Department, University of Pavia, Pavia, Italy
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Croce AC, Ferrigno A, Bertone V, Piccolini VM, Berardo C, Di Pasqua LG, Rizzo V, Bottiroli G, Vairetti M. Fatty liver oxidative events monitored by autofluorescence optical diagnosis: Comparison between subnormothermic machine perfusion and conventional cold storage preservation. Hepatol Res 2017; 47:668-682. [PMID: 27448628 DOI: 10.1111/hepr.12779] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/13/2016] [Accepted: 07/18/2016] [Indexed: 12/16/2022]
Abstract
AIMS Livers with moderate steatosis are currently recruited as marginal organs to face donor shortage in transplantation, even though lipid excess and oxidative stress increase preservation injury risk. Sensitive, real-time detection of liver metabolism engagement could help donor selection and preservation procedures, ameliorating the graft outcome. Hence, we investigated endogenous biomolecules with autofluorescence (AF) properties as biomarkers supporting the detection of liver oxidative events and the assessment of metabolic responses to external stimuli. METHODS Livers from male Wistar rats fed a 12-day methionine/choline-deficient (MCD) diet were subjected to AF spectrofluorometric analysis (fiber-optic probe, 366-nm excitation) before and after organ isolation, and following preservation (cold storage or 20°C machine perfusion) and reperfusion. RESULTS Innovative dynamic AF results on lipid oxidation to lipofuscin-like lipopigments, correlating with biochemical oxidative damage (thiobarbituric acid reactive substances) and antioxidant defense (glutathione) parameters, suggested lipid engagement in MCD livers counteracting reactive oxidizing species. The maintained MCD liver functionality was supported by limited changes in bilirubin AF spectral profile, reflecting bile composition balance, despite their intrinsic mitochondrial weakness, confirmed by adenosine 5'-triphosphate levels, and regardless of different preservation effects on energy metabolism revealed by conventional reduced forms of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate and flavin AF data. CONCLUSION Autofluorescence showed that, after a relatively short time on an MCD diet, livers are still able to face oxidizing events and maintain a functional balance. These results strengthen AF as a supportive diagnostic tool in experimental hepatology, to characterize marginal livers in real time, monitor their response to ischemia/reperfusion, and investigate protective therapeutic agents.
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Affiliation(s)
- Anna Cleta Croce
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), San Matteo, Pavia, Italy.,Biology and Biotechnology Department, University of Pavia, Pavia, Italy
| | - Andrea Ferrigno
- Internal Medicine and Therapy Department, University of Pavia, Pavia, Italy
| | - Vittorio Bertone
- Biology and Biotechnology Department, University of Pavia, Pavia, Italy
| | - Valeria Maria Piccolini
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), San Matteo, Pavia, Italy
| | - Clarissa Berardo
- Internal Medicine and Therapy Department, University of Pavia, Pavia, Italy
| | | | - Vittoria Rizzo
- Molecular Medicine Department, University of Pavia and Istituto Ricovero e Cura Carattere Scientifico (IRCCS), San Matteo, Pavia, Italy
| | - Giovanni Bottiroli
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), San Matteo, Pavia, Italy.,Biology and Biotechnology Department, University of Pavia, Pavia, Italy
| | - Mariapia Vairetti
- Internal Medicine and Therapy Department, University of Pavia, Pavia, Italy
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Croce AC, Ferrigno A, Di Pasqua LG, Berardo C, Piccolini VM, Bertone V, Bottiroli G, Vairetti M. Autofluorescence discrimination of metabolic fingerprint in nutritional and genetic fatty liver models. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 164:13-20. [DOI: 10.1016/j.jphotobiol.2016.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 09/09/2016] [Accepted: 09/10/2016] [Indexed: 12/21/2022]
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Croce AC, Ferrigno A, Santin G, Piccolini VM, Bottiroli G, Vairetti M. Autofluorescence of liver tissue and bile: organ functionality monitoring during ischemia and reoxygenation. Lasers Surg Med 2014; 46:412-21. [PMID: 24619664 DOI: 10.1002/lsm.22241] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVE Autofluorescence (AF) based optical biopsy of liver tissue is a powerful approach for the real-time diagnosis of its functionality. Since increasing attention is given to the bile production and composition to monitor the liver metabolic engagement in surgery and transplantation, we have investigated the bile AF properties as a potential, additional diagnostic parameter. STUDY DESIGN/MATERIALS AND METHODS Spectrofluorometric analysis has been performed in real time on a rat liver model of warm ischemia and reperfusion-60 minutes partial portal vein and hepatic artery clamping and subsequent restoration of blood circulation-in comparison with sham operated rats. The AF spectra have been recorded through a single fiber optic probe (366 nm excitation) from both liver tissue and bile, collected from the cannulated bile duct, and analyzed by means of curve fitting procedures. Bile composition has been also analyzed through biochemical assays of bilirubin, total bile acids (TBA) and proteins. RESULTS Both liver and bile AF signal amplitude and spectral shape undergo changes during induction of ischemia and subsequent reperfusion. The liver tissue response is mainly ascribable to changes in NAD(P)H and flavins and their redox state, largely dependent on oxygen supply, and to the decrease of both vitamin A and fatty acid AF contributions. During comparable times, sham operated rat livers undergo smaller alterations in AF spectral shape, indicating a continuous, slight increase in the oxidized state. Bile AF emission shows a region in the 510-600 nm range ascribable to bilirubin, and resulting from the contribution of two bands, centered at about 515-523 and 570 nm, consistently with its bichromophore nature. Variations in the balance between these two bands depend on the influence of microenvironment on bilirubin intramolecular interchromophore energy transfer efficiency and are likely indicating alteration in a bile composition. This event is supported also by changes observed in the 400-500 nm emission region, ascribable to other bile components. CONCLUSIONS In parallel with the intratissue AF properties, mainly reflecting redox metabolic activities, the bile AF analysis can provide additional information to assess alterations and recovery in the balance of liver metabolic activities.
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Affiliation(s)
- Anna C Croce
- Histochemistry and Cytometry Unit, IGM-CNR, Biology and Biotechnology Department, University of Pavia, 27100, Pavia, Italy
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Chow AM, Chan KW, Fan SJ, Yang J, Cheung JS, Khong PL, Wu EX. In vivo proton magnetic resonance spectroscopy of hepatic ischemia/reperfusion injury in an experimental model. Acad Radiol 2011; 18:246-52. [PMID: 21111640 DOI: 10.1016/j.acra.2010.09.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 06/02/2010] [Accepted: 09/20/2010] [Indexed: 01/03/2023]
Abstract
RATIONALE AND OBJECTIVES Hepatic ischemia/reperfusion injury (IRI) occurs during certain hepatobiliary surgeries, hemorrhagic shock, and veno-occlusive disease. Biochemical changes caused by hepatic IRI lead to hepatocellular remodeling, including cellular regeneration or irreversible apoptosis. This study aims to characterize and monitor the metabolic changes in hepatic IRI using proton magnetic resonance spectroscopy (¹H MRS). MATERIALS AND METHODS Sprague-Dawley rats (n = 8) were scanned with ¹H MRS using 5.0 × 5.0 × 5.0 mm³ voxel over a homogeneous liver parenchyma at 7 Tesla with a respiratory-gated point-resolved spectroscopy sequence at 1 day before, 6 hours, 1 day, and 1 week after 30 minutes total hepatic IRI. Signal integral ratios of choline-containing compounds (CCC), glycogen and glucose complex (Glyu), methylene proton ((-CH₂-)(n)), and methene proton (-CH=CH-) to lipid (integral sum of methyl proton (-CH₃), (-CH₂-)(n) and -CH=CH-) were quantified by areas under peaks longitudinally. RESULTS The CCC-to-lipid and Glyu-to-lipid ratios at 6 hours after IRI were significantly higher than those at 1 day before, 1 day, and 1 week after injury. The (-CH₂-)(n)-to-lipid, and -CH=CH-to-lipid ratios showed no significant differences over different time points. Hepatocellular regeneration was observed at 6 hours after IRI in histology with immunohistochemical technique. CONCLUSIONS Changes in CCC-to-lipid and Glyu-to-lipid ratios likely reflect the hepatocellular remodeling and impaired glucose utilization upon hepatic IRI, respectively. The experimental findings in the current study demonstrated that ¹H MRS is a valuable tool for characterizing either global or regional metabolic changes in liver noninvasively and longitudinally. Such capability has the potential to lead to early diagnosis and detection of impaired liver function.
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Váli L, Stefanovits-Bányai E, Szentmihályi K, Fébel H, Sárdi E, Lugasi A, Kocsis I, Blázovics A. Liver-protecting effects of table beet (Beta vulgaris var. rubra) during ischemia-reperfusion. Nutrition 2007; 23:172-8. [PMID: 17234508 DOI: 10.1016/j.nut.2006.11.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2006] [Revised: 11/03/2006] [Accepted: 11/06/2006] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Table beet (Beta vulgaris var. rubra) contains important bioactive agents (betaine and polyphenols), which have a wide range of physiologic effects. Because nutritive antioxidants may reduce the occurrence of complications and postoperative mortality, dietary intake of polyphenols and vitamins before surgery may greatly contribute to the survival of patients. Our aim was to determine the liver-protecting properties of bioactive substances of table beet in a model of ischemia-reperfusion injury of the rat. METHODS Wistar rats were divided into two groups: non-treated (n = 24) and fed with table beet (n = 8). For 10 days the second group was treated with lyophilized table beet (2 g/kg body weight daily) mixed into the rat chow. Hepatic ischemia was maintained for 45 min, followed by 15 min of reperfusion. Ischemia-reperfusion was carried out on animals from both groups. Chemiluminescent intensity, H-donating ability, reducing power, free SH group concentration, Randox-total antioxidant status, glutathione peroxidase, and superoxide dismutase activities were determined by luminometry and spectrophotometry. Fatty acid (Shimadzu GC) and metal ion (inductively coupled plasma optical emission spectrometry) concentrations were observed in the liver. RESULTS As a result of feeding, global parameters (H-donating ability, reducing power, free SH group concentration) and enzymatic antioxidants (glutathione peroxidase and superoxide dismutase) of the liver were found to increase significantly, which indicated that the treatment had a positive effect on its redox state. The increase found in zinc and copper content may protect the hepatocytes against oxidative stress because these elements are required for the function of superoxide dismutase enzymes. In the table beet group the concentration of short-chain fatty acids decreased, whereas that of long-chain fatty acids increased. The changes in metal element and fatty acid concentrations confirmed that these elements have an essential function in cellular pathways. CONCLUSION It may be stated that a natural antioxidant-rich diet has a positive effect on redox homeostasis during hepatic ischemia-reperfusion.
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Affiliation(s)
- László Váli
- II Department of Medicine, Semmelweis University, Budapest, Hungary
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Tsoutsikos P, Miners JO, Stapleton A, Thomas A, Sallustio BC, Knights KM. Evidence that unsaturated fatty acids are potent inhibitors of renal UDP-glucuronosyltransferases (UGT): kinetic studies using human kidney cortical microsomes and recombinant UGT1A9 and UGT2B7. Biochem Pharmacol 2004; 67:191-9. [PMID: 14667942 DOI: 10.1016/j.bcp.2003.08.025] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Renal ischaemia is associated with accumulation of fatty acids (FA) and mobilisation of arachidonic acid (AA). Given the capacity of UDP-glucuronosyltransferase (UGT) isoforms to metabolise both drugs and FA, we hypothesised that FA would inhibit renal drug glucuronidation. The effect of FA (C2:0-C20:5) on 4-methylumbelliferone (4-MU) glucuronidation was investigated using human kidney cortical microsomes (HKCM) and recombinant UGT1A9 and UGT2B7 as the enzyme sources. 4-MU glucuronidation exhibited Michaelis-Menten kinetics with HKCM (apparent K(m) (K(m)(app)) 20.3 microM), weak substrate inhibition with UGT1A9 (K(m)(app) 10.2 microM, K(si) 289.6 microM), and sigmoid kinetics with UGT2B7 (S(50)(app)440.6 microM) Similarly, biphasic UDP-glucuronic acid (UDPGA) kinetics were observed with HKCM (S(50) 354.3 microM) and UGT1A9 (S(50) 88.2 microM). In contrast, the Michaelis-Menten kinetics for UDPGA observed with UGT2B7 (K(m)(app) 493.2 microM) suggested that kinetic interactions with UGTs were specific to the xenobiotic substrate and the co-substrate (UDPGA). FA (C16:1-C20:5) significantly inhibited (25-93%) HKCM, UGT1A9 or UGT2B7 catalysed 4-MU glucuronidation. Although linoleic acid (LA) and AA were both competitive inhibitors of 4-MU glucuronidation by HKCM (K(i)(app) 6.34 and 0.15 microM, respectively), only LA was a competitive inhibitor of UGT1A9 (K(i)(app) 4.06 microM). In contrast, inhibition of UGT1A9 by AA exhibited atypical kinetics. These data indicate that LA and AA are potent inhibitors of 4-MU glucuronidation catalysed by human kidney UGTs and recombinant UGT1A9 and UGT2B7. It is conceivable therefore that during periods of renal ischaemia FA may impair renal drug glucuronidation thus compromising the protective capacity of the kidney against drug-induced nephrotoxicity.
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Affiliation(s)
- Paraskevi Tsoutsikos
- Department of Clinical Pharmacology, Flinders University and Flinders Medical Centre, Bedford Park, 5042, Adelaide, Australia
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Ricciardi R, Veal TM, Anwaruddin S, Wheeler SM, Foley DP, Donohue SE, Quarfordt SH, Meyers WC. Porcine hepatic phospholipid efflux during reperfusion after cold ischemia. J Surg Res 2002; 103:79-88. [PMID: 11855921 DOI: 10.1006/jsre.2001.6341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Cold preservation produces hepatic injury that is difficult to assess during early reperfusion. The value of reperfusion plasma choline phospholipid in predicting subsequent organ function is documented in these studies. MATERIALS AND METHODS Livers of female Yorkshire pigs were prepared for transplantation. After 2 h of cold ischemia the reperfusion plasma was evaluated for choline phospholipid and cholesterol. These values were correlated with bile secretion, hepatic hemodynamics, oxygen uptake, and plasma sorbitol dehydrogenase levels. RESULTS The isolated porcine liver demonstrates a rapid efflux of choline phospholipids into plasma during early reperfusion after cold preservation. After this initial efflux no subsequent plasma increment occurred. These choline-phospholipid increments were isolated in plasma higher density (d > 1.063) lipoproteins and were not accompanied by equivalent increases in cholesterol. Neither biliary reflux nor lecithin cholesterol acyl transferase abnormalities contributed appreciably to the phospholipid increments in reperfusion plasma. Livers with the largest efflux of choline phospholipids had the most impaired circulatory and bile secretory function at 4 h of reperfusion. CONCLUSION The immediate increase of choline phospholipids, particularly lysophosphatidylcholine, in reperfusion plasma after cold ischemia provides an index of the injury occurring during this interval and correlates with early organ function.
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Affiliation(s)
- Rocco Ricciardi
- Department of Surgery, UMass Memorial Medical Center, Worcester, Massachusetts, 01655, USA
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Chen J, Liu X, Mandel LJ, Schnellmann RG. Progressive disruption of the plasma membrane during renal proximal tubule cellular injury. Toxicol Appl Pharmacol 2001; 171:1-11. [PMID: 11181106 DOI: 10.1006/taap.2000.9105] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The goal of this study was to examine the progression of plasma membrane disruption during cell injury using rabbit renal proximal tubules (RPT). The results demonstrated that the plasma membrane became permeable to larger and larger molecules as anoxia proceeded. At least three distinctive phases of membrane disruption were differentiated during anoxia. In phases 1, 2, and 3, plasma membranes became permeable to propidium iodide (PI, molecular weight = 668), 3 kDa dextrans, and 70 kDa dextrans or lactate dehydrogenase (LDH, molecular weight = 140 kDa), respectively. Phase 1 was reversible by reoxygenation but not prevented by the glycine. Phase 2 was inhibited by glycine. Phase 3 was inhibited by several membrane-permeable homobifunctional crosslinkers, dimethyl-pimelimidate (DMP), ethylene-glycolbis(succinimidylsuccinate), and dithiobis(succinimidylpropionate), but not by the membrane-impermeable crosslinker dithiobis(sulfosuccinimidylpropionate). In addition, DMP decreased RPT LDH release produced by mitochondrial inhibition (antimycin A), an oxidant (t-butylhydroperoxide) and a nephrotoxicant that is metabolized to an electrophile (tetrafluoroethyl-l-cysteine). These results identify (1) different phases of plasma membrane damage with increasing permeability during cell injury, (2) the reversibility of phase 1, (3) the relative site of action of the cytoprotectant glycine (prevents phase 2), and (4) the protective effects of chemical crosslinkers in RPT cell death produced by different toxicants.
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Affiliation(s)
- J Chen
- Department of Life Sciences, Indiana State University, Terre Haute, Indiana 47809, USA
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12
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Zager RA, Sacks BM, Burkhart KM, Williams AC. Plasma membrane phospholipid integrity and orientation during hypoxic and toxic proximal tubular attack. Kidney Int 1999; 56:104-17. [PMID: 10411684 DOI: 10.1046/j.1523-1755.1999.00533.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Acute cell injury can activate intracellular phospholipase A2 (PLA2) and can inhibit plasma membrane aminophospholipid translocase(s). The latter maintains inner/outer plasma membrane phospholipid (PL) asymmetry. The mechanistic importance of PLA2-mediated PL breakdown and possible PL redistribution ("flip flop") to lethal tubule injury has not been well defined. This study was performed to help clarify these issues. METHODS Proximal tubule segments (PTS) from normal CD-1 mice were subjected to either 30 minutes of hypoxia, Ca2+ ionophore (50 microM A23187), or oxidant attack (50 microM Fe). Lethal cell injury [the percentage of lactate dehydrogenase (LDH) release], plasma membrane PL expression [two-dimensional thin layer chromatography (TLC)], and free fatty acid (FFA) levels were then assessed. "Flip flop" was gauged by preferential decrements in phosphatidylserine (PS) versus phosphatidylcholine (PC; PS/PC ratios) in response to extracellular (Naja) PLA2 exposure. RESULTS Hypoxia induced approximately 60% LDH release, but no PL losses were observed. FFA increments suggested, at most 3% or less PL hydrolysis. Naja PLA2 reduced PLs in hypoxic tubules, but paradoxically, mild cytoprotection resulted. In contrast to hypoxia, Ca2+ ionophore and Fe each induced significant PL losses (6 to 15%) despite minimal FFA accumulation or cell death (26 to 27% LDH release). Arachidonic acid markedly inhibited PLA2 activity, potentially explaining an inverse correlation (r = -0.91) between tubule FFA accumulation and PL decrements. No evidence for plasma membrane "flip flop" was observed. In vivo ischemia reperfusion and oxidant injury (myohemoglobinuria) induced 0 and 24% cortical PL depletion, respectively, validating these in vitro data. CONCLUSIONS (a) Plasma membrane PLs are well preserved during acute hypoxic/ischemic injury, possibly because FFA accumulation (caused by mitochondrial inhibition) creates a negative feedback loop, inhibiting intracellular PLA2. (b) Exogenous PLA2 induces PL losses during hypoxia, but decreased cell injury can result. Together these findings suggest that PL loss may not be essential to hypoxic cell death. (c) Oxidant/Ca2+ overload injury induces early PL losses, perhaps facilitated by ongoing mitochondrial FFA metabolism, and (d) membrane "flip flop" does not appear to be an immediate mediator of acute necrotic tubular cell death.
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Affiliation(s)
- R A Zager
- The Fred Hutchinson Cancer Research Center, University of Washington, Seattle 98109, USA.
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Peters SM, de Jong MD, Bindels RJ, van Os CH, Wetzels JF. Effects of renal cytoprotective agents on erythrocyte membrane stability. Life Sci 1998; 63:975-83. [PMID: 9747898 DOI: 10.1016/s0024-3205(98)00355-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To elucidate potential mechanisms of ischemic renal injury, investigators often use drugs that interfere with specific pathological pathways and study their protective efficacy in in vitro models of ischemia, such as isolated renal proximal tubules subjected to hypoxia. However, the protective effects of certain drugs may depend on non-specific membrane-stabilizing properties. We have studied the effects of several drugs on membrane integrity using osmotic lysis of erythrocytes as a model system. Freshly isolated rabbit erythrocytes were subjected to a hypotonic shock, and the protective effects of various calcium channel blockers, phospholipase inhibitors, free fatty acids, the NO-synthase inhibitor L-NAME, the amino acid glycine and its receptor-analogue strychnine, and two chloride channel blockers were examined. Most agents protected erythrocytes against hypotonic hemolysis when added to the medium in the same concentration range as used in suspensions of hypoxic proximal tubules. Only the protective agents that proposedly act via a blockade of chloride influx (glycine, strychnine and the chloride channel blockers), did not attenuate hypotonic hemolysis. The erythrocyte hemolysis assay may provide an easy and rapid method to screen for non-specific membrane-stabilizing effects of potentially cytoprotective agents.
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Affiliation(s)
- S M Peters
- Department of Cell Physiology, University of Nijmegen, The Netherlands
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14
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Hayakawa Y, Yoshioka Y, Yasuda N. Effects of ligation and reperfusion of hepatic afferent vessels on the composition of liver cell membrane in the rat: 1H- and 31P-magnetic resonance spectroscopic analysis. NMR IN BIOMEDICINE 1997; 10:257-262. [PMID: 9449128 DOI: 10.1002/(sici)1099-1492(199709)10:6<257::aid-nbm471>3.0.co;2-b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Biochemical changes that occur within hepatic tissue of the rat during ischemia and subsequent reperfusion were investigated using magnetic resonance spectroscopy of liver extracts. Hepatic ischemia was produced in the rat by a continuous clamping of the left branches of the hepatic artery and portal vein. In the reperfusion experiments, the vascular clamps were released after 30 or 120 min of ischemic periods. At the end of the periods of ischemia and/or reperfusion, the left and middle hepatic lobes were dissected and processed for subsequent 1H-MRS and 31P-MRS analyses. Phosphatidylcholine, sphingomyelin, phosphatidic acid and phosphatidylethanolamine contents all showed reduction of about 30% after 120 min of ischemia. In contrast, the content of lysophosphatidylcholine showed relatively small changes following ischemia. Ten minutes after initiation of reperfusion, further decline of the total phospholipid content resulting in as much 42% reduction was observed. Then it recovered to nearly the control level when ischemia was for 30 min, but to only 65% of the control level when ischemia was for 120 min. The cholesterol/-N-(CH3)3 ratio, generally regarded as a parameter for membrane fluidity, showed about a 40% increase when ischemia was for 120 min, a change toward decreased membrane fluidity. These results appear to reflect ischemia/reperfusion-induced changes of membrane phospholipid metabolism.
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Affiliation(s)
- Y Hayakawa
- Second Department of Physiology, School of Medicine, Iwate Medical University, Japan
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15
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Sakaida I, Nagatomi A, Okita K. Protection by glycine against chemical ischemia produced by cyanide in cultured hepatocytes. J Gastroenterol 1996; 31:684-90. [PMID: 8887035 DOI: 10.1007/bf02347617] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The killing of cultured hepatocytes by cyanide accelerated phospholipid metabolism, with a reduction in cytoplasmic pH, but did not accelerate proteolysis. Alkalinization of the cytoplasm by monensin, a protonsodium exchange ionophore, enhanced the loss of viability and acceleration of phospholipid metabolism caused by cyanide. Thus, acidification of the cytoplasm appears to protect against the toxic effects of cyanide. Glycine reduced the killing of hepatocytes, concomitant with reduced phospholipid metabolism. The protective effect of glycine neither enhanced the reduction in cytoplasmic pH nor prevented the depletion of adenosine triphosphate (ATP) by cyanide. The mechanism of the protection exerted by glycine against chemical ischemia can be attributed neither to changes in cytoplasmic pH nor to the prevention of ATP depletion, but appears to be due to other mechanisms that have yet to be identified.
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Affiliation(s)
- I Sakaida
- First Department of Internal Medicine, School of Medicine, Yamaguchi University, Japan
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16
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Reddy MC, Koneru B, Soni S, Patel D. 31P nuclear magnetic resonance study of phospholipids in ischemia/reperfusion injury in a rat fatty liver model. Transplantation 1996; 61:1151-5. [PMID: 8610409 DOI: 10.1097/00007890-199604270-00005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Obese Zucker rats are susceptible to increased hepatic ischemia/reperfusion (I/RP) injury. Increased lipid peroxidation occurs in this model with warm ischemia. We hypothesized that a severe depletion of phospholipids (PL) occurs with warm I/RP in fatty livers. Obese (Ob) and lean (Ln) Zucker rats were subjected to 90 min of in vivo partial hepatic warm I followed by RP. Total lipids extracted from one gm of liver (median lobe) taken at the end of 1, 2 and 6 hr of RP and sham (Sh) surgery (n=5 Ln & Ob) were analyzed by 202.3 MHz 31P NMR, which provided good resolution of individual PL. Obese (Sh) rats contained 22% more PL than Ln (P= < 0.01). Ischemia caused similar decreases in PL in both Ob (to 67% Sh) and Ln rats (62%). Following 2 hr RP, PL in Ob rats decreased further (46% Sh) and recovered only marginally at 6 hr (53%), in marked contrast to the rapid recovery in Ln to preischemic levels (110% Sh at both 2 and 6 hr; P=<0.001). Mole percents of individual PL did not change significantly except for lysophosphatidylcholine, which increased from 0.43 to 1.3% (Sh vs. 6 hr RP) in the Ob, but decreased from 0.98 to 0.52% in Ln animals (P = <0.001). Fatty livers thus are more vulnerable to phospholipid depletion in response to warm ischemia/reperfusion than normal livers.
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Affiliation(s)
- M C Reddy
- The Department of Surgery, University of Medicine and Dentistry, New Jersey Medical School, Newark, NJ 07103, USA
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17
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Hamamoto I, Nemoto EM, Zhang S, Hartwell VR, Todo S. Assessment of hepatic viability during cold ischemic preservation. Transpl Int 1995. [DOI: 10.1111/j.1432-2277.1995.tb01552.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Singh AK, Gulati S. Effect of ischemia-reperfusion injury on the morphology of peroxisomes. Mol Cell Biochem 1995; 144:19-26. [PMID: 7791741 DOI: 10.1007/bf00926736] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have previously demonstrated that ischemic injury changed the density of peroxisomes into two distinct peaks, one with a normal density (1.21 g/cm3; Peak I) and a second peak with a lighter density (1.14 g/cm3; Peak II). We studied the peroxisomes from both peaks under the Electron microscope. Examination of peak I following ischemia showed loss of matrix proteins and damaged limiting membranes with leakage of DAB positive material in direct proportion to the duration of ischemia. Upon reperfusion of the ischemic liver Peak I showed more severe damage to the organelle. These observations clearly demonstrated that ischemia reperfusion injury causes structural damage to peroxisomes. Interestingly ultrastructural examination of Peak II following ischemia showed evidence of perisomal proliferation with budding of existing peroxisomes and the presence of micro peroxisomes (changes similar to those noted under conditions leading to perisomal proliferation). However, peak II following reperfusion showed only damaged organelle. These observations underline the importance of peroxisomes in the response of the cell to ischemia-reperfusion injury.
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Affiliation(s)
- A K Singh
- Department of Pathology, Ralph H. Johnson V.A. Medical Center, Charleston, S.C. 29401, USA
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19
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Schnellmann RG, Yang X, Carrick JB. Arachidonic acid release in renal proximal tubule cell injuries and death. JOURNAL OF BIOCHEMICAL TOXICOLOGY 1994; 9:211-7. [PMID: 7853355 DOI: 10.1002/jbt.2570090406] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Arachidonic acid release and the effect of phospholipase inhibitors on various types of cell injuries and death to rabbit renal proximal tubule suspensions were determined. Proximal tubules were exposed to the mitochondrial inhibitor antimycin A (0.1 microM), the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (1 microM FCCP), the oxidant tert-butyl hydroperoxide (0.5 mM TBHP), or the calcium ionophore ionomycin (5 microM) in the absence or presence of the putative phospholipase inhibitors dibucaine, mepacrine, chlorpromazine, or U-26384. The phospholipase inhibitors had no effect on the proximal tubule lactate dehydrogenase (LDH) release (a marker of cell death) produced by FCCP, antimycin A, or ionomycin after 1,2, or 2 hours of exposure, respectively. Only dibucaine and mepacrine decreased LDH release in TBHP-treated proximal tubules without decreasing TBHP-induced lipid peroxidation. Antimycin A and ionomycin did not release arachidonic acid from proximal tubules prelabeled with [1-14C] arachidonic acid. In contrast, TBHP released arachidonic acid from proximal tubules prior to the onset of cell death, and dibucaine and mepacrine decreased the TBHP-induced release. Thus, phospholipase inhibitors were cytoprotective in those injuries that produced arachidonic acid release. These results suggest that arachidonic acid release and phospholipase A2 activation play a contributing role in oxidant-induced renal proximal tubule cell injury and death but not in mitochondrial inhibitor- or calcium ionophore-induced proximal tubule cell injury and death.
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Affiliation(s)
- R G Schnellmann
- Department of Physiology and Pharmacology, College of Veterinary Medicine, Athens, GA
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20
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Gulati S, Singh AK, Irazu C, Orak J, Rajagopalan PR, Fitts CT, Singh I. Ischemia-reperfusion injury: biochemical alterations in peroxisomes of rat kidney. Arch Biochem Biophys 1992; 295:90-100. [PMID: 1575521 DOI: 10.1016/0003-9861(92)90492-f] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Exogenously supplied catalase, a peroxisomal enzyme, has been found to be of therapeutic value in ischemic injury. Therefore, we examined the effect of ischemic-reperfusion injury on the structure and function of kidney peroxisomes. Ischemic injury changed the density of peroxisomes from 1.21 g/cm3 (peak I) to a lighter density of 1.14 g/cm3 (peak II). The number of peroxisomes moving from the normal density population (peak I) to a lower density population (peak II) increased with an increase in ischemic injury. Latency experiments indicated both populations of peroxisomes to be of intact peroxisomes. Immunoblot analysis with antibodies against peroxisomal matrix and membrane proteins demonstrated that after 90 min of ischemia a significant number of matrix proteins were lost in the peak II population, suggesting that functions of these peroxisomes may be severally affected. Reperfusion following ischemic injury resulted in loss of peroxisomal matrix proteins in both peaks I and II, suggesting that peroxisomal functions may be drastically compromised. This change in peroxisomal functions is reflected by a significant decrease in peroxisomal catalase activity (35%) and beta-oxidation of lignoceric acid (43%) observed following 90 min of ischemia. The decrease in catalase activity was more pronounced in reperfused kidneys even after a shorter term of ischemic injury. Reperfusion restored the normal peroxisomal beta-oxidation in kidneys exposed up to 60 min of ischemia. However, 90 min of ischemia was irreversible as there was a further decrease in beta-oxidation upon reperfusion. The decrease in catalase activity during ischemia alone was due to the formation of an inactive complex, whereas during reperfusion, following 90 min of ischemia, inactivation and proteolysis or decreased synthesis of catalase contributed equally toward the injury. The observed changes in the structure and function of peroxisomes as a result of ischemic-reperfusion injury and the ubiquitous distribution of peroxisomes underlines the importance of this organelle in the pathophysiology of vascular injury in general.
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Affiliation(s)
- S Gulati
- Department of Pediatrics, Medical University of South Carolina, Charleston 29425
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21
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Beckman JK, Yoshioka T, Knobel SM, Greene HL. Biphasic changes in phospholipid hydroperoxide levels during renal ischemia/reperfusion. Free Radic Biol Med 1991; 11:335-40. [PMID: 1797621 DOI: 10.1016/0891-5849(91)90148-v] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The involvement of lipid peroxidation in renal ischemia/reperfusion was explored by measuring changes in the cortical content of specific primary lipid hydroperoxides (using chemluminescent detection with HPLC) following ischemia and reperfusion and by correlating the changes in hydroperoxide content with measurements of renal blood flow. Phosphatidylcholine and phosphatidylethanolamine hydroperoxide concentrations were significantly lowered during 30 or 60 min of ischemia (to levels less than 50% of control at 60 min). Following 30 min of renal ischemia, reperfusion resulted in a rebound of phospholipid hydroperoxide tissue content to levels higher than controls. Increased phospholipid hydroperoxide formation was not, however, observed in response to reperfusion following long-term (60 min) ischemia. In separate animals it was demonstrated that following 30 min ischemia and reperfusion, renal blood flow recovers to about 65% of control in 1 h. In contrast, following 60 min ischemia and reperfusion, the renal blood flow remains more highly impaired (less than 25% recovery for periods up to 24 h). These results imply that phospholipid hydroperoxides are produced and accumulate in the kidneys under normal aerobic conditions and that lipid peroxidative activity increases during renal ischemia/reperfusion to an extent dependent on the degree of local blood perfusion.
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Affiliation(s)
- J K Beckman
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232
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22
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Cighetti G, Del Puppo M, Paroni R, Galli Kienle M. Lack of conversion of xanthine dehydrogenase to xanthine oxidase during warm renal ischemia. FEBS Lett 1990; 274:82-4. [PMID: 2253787 DOI: 10.1016/0014-5793(90)81334-k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Irreversible transformation of xanthine dehydrogenase (XDH) to xanthine oxidase (XO) during ischemia was determined measuring XDH and total enzyme activity in kidneys before and after 60 min of clamp of the renal pedicle. Tissue levels of adenine nucleotides, xanthine and hypoxanthine were used as indicators of ischemia. After 60 min of clamping, ATP levels decreased by 72% with respect to controls whereas xanthine and hypoxanthine progressively reached tissue concentrations of 732 +/- 49 and 979 +/- 15 nmol.g tissue-1, respectively. Both total and XDH activities in ischemic kidneys (30 +/- 15 and 19 +/- 1 nmol.min-1.g tissue-1) were significantly lower than in controls when expressed on a tissue weight basis. The fraction of enzyme in the XDH form was however unchanged indicating that the reduction of the nucleotide pool is not accompanied by induction of the type-O activity of xanthine oxidase.
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23
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Kehrer JP, Jones DP, Lemasters JJ, Farber JL, Jaeschke H. Mechanisms of hypoxic cell injury. Summary of the symposium presented at the 1990 annual meeting of the Society of Toxicology. Toxicol Appl Pharmacol 1990; 106:165-78. [PMID: 2256109 DOI: 10.1016/0041-008x(90)90238-p] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- J P Kehrer
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas, Austin 78712
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24
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Coleman JB, Condie LW, Lamb RG. The influence of CCl4 biotransformation on the activation of rat liver phospholipase C in vitro. Toxicol Appl Pharmacol 1988; 95:200-7. [PMID: 3420612 DOI: 10.1016/0041-008x(88)90156-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Carbon tetrachloride (CCl4) biotransformation and covalent binding was measured in 1000g liver fractions by determining the amount of 14CCl4 metabolites covalently bound to proteins and lipids at various (5-60 min) incubation times. Reactive intermediate binding to proteins and phospholipids peaked at 20 min, whereas CCl4 metabolites associated with neutral lipids (primarily diacylglycerol) were initially low (0-15 min) and then gradually increased from 20 to 60 min. The rise in labeled diacylglycerol was associated with a decrease in phospholipids containing covalently bound CCl4 metabolites, since CCl4 bioactivation increased phospholipase C (PLC) activity three- to fourfold. The major rise in PLC activity occurred after the plateau of CCl4 metabolite binding to cellular phospholipids. In contrast, when CCl4 bioactivation is absent, 0.5 mM CCl4 has little effect on PLC activity. At CCl4 concentrations of 1 mM and greater, the NADPH-dependent activation of PLC by CCl4 is reduced because CCl4 biotransformation is inhibited. Nevertheless, PLC is still activated by CCl4; however, PLC activation by high doses of CCl4 occurs by bioactivation-independent mechanisms. Therefore, there are two components of CCl4-induced PLC activation: one which is dependent on CCl4 biotransformation and one which is not. Under both conditions (+/- biotransformation), the activation of PLC may be a key event in CCl4 hepatotoxicity since PLC disrupts the functional and structural integrity of membranes by degrading membrane phospholipids.
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Affiliation(s)
- J B Coleman
- Department of Pharmacology, Medical College of Virginia, Richmond 23298-0217
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25
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Coleman JB, Condie LW, Lamb RG. The role of CCl4 biotransformation in the activation of hepatocyte phospholipase C in vivo and in vitro. Toxicol Appl Pharmacol 1988; 95:208-19. [PMID: 3420613 DOI: 10.1016/0041-008x(88)90157-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Rats treated with a single 0.5 ml/kg dose (ip) of CCl4 exhibited a threefold increase in liver microsomal phospholipase C (PLC) activity that was enhanced by phenobarbital and diminished by metyrapone pretreatment, respectively. Hepatocytes and hepatocellular fractions exposed to 0.5 mM CCl4 in vitro also exhibited a rapid rise in PLC activity that was reduced by metyrapone. Metyrapone also reduced the CCl4-related increase in the PLC-mediated reductions in cellular phosphatidylcholine content. The influence of CCl4 biotransformation on the activation of liver cell PLC was assessed in vitro. Covalent binding of 14CCl4 metabolites to isolated hepatocyte proteins and lipids was linear through 20 min of incubation and then quickly plateaued. The association of CCl4 metabolites with cellular phospholipids was inhibited by metyrapone and preceded the CCl4-dependent rise in PLC activity. CCl4-mediated increases in PLC activity were rapid and preceded reductions in cell viability. The translocation of cytosolic PLC to membranes such as the endoplasmic reticulum may explain the rapid, metabolite-dependent activation of PLC.PLC activation by haloalkanes was proportional to dose and incubation time in the order of CBrCl3 greater than CCl4 greater than CHCl3 greater than CFCl3 which corresponds to the observed hepatotoxic potential of these agents in vivo and in vitro. Haloalkane-dependent increases in PLC activity were inhibited by metyrapone. These results suggest that chemical metabolites activate PLC in vitro and in vivo. Therefore, the activation of a PLC that degrades membrane phospholipids may represent an important step in the pathogenic scheme of chemical-mediated liver cell necrosis.
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Affiliation(s)
- J B Coleman
- Department of Pharmacology, Medical College of Virginia, Richmond 23298-0217
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26
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Osada J, Aylagas H, Mirò-Obradors MJ, Palacios-Alaiz E. Lyso-phosphatidylcholine is implicated in thioacetamide-induced liver necrosis. Biochem Biophys Res Commun 1988; 154:803-8. [PMID: 3401237 DOI: 10.1016/0006-291x(88)90211-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Thioacetamide is a weak hepatocarcinogen. To determine whether alterations in lysophosphatidylcholine are implicated in thioacetamide-induced hepatic necrosis, rats were injected i.p. with this agent (50 mg/Kg body weight per day) or diluent for 1, 3, 8 and 30 days. Serum catalytic activities of aminotransferases were determined. Incorporation of (32P)-orthophosphate into hepatic lysophosphatidylcholine was also evaluated in animals killed 75 minutes or 13 hours after isotope administration. Results demonstrate that: A significant increase in hepatic lysolecithin concentration occurs when a maximum level of serum aminotransferases is present. An increase of (32P)-orthophosphate radioactive incorporation in lysolecithin was observed at the two assayed labelling periods, which suggest an activation of phospholipase A. The radioactivity present in lysolecithin after 13 h isotope injection showed a close correlation with serum level of aminotransferases. From these results it can be deduced that lysolecithin is implicated in TAA-induced necrosis and may be generated by increase in either phospholipase A activity and/or synthesis.
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Affiliation(s)
- J Osada
- Instituto de Bioquìmica, Centro Mixto (C.S.I.C.-U.C.M.) Facultad de Farmacia Universidad Complutense, Madrid, España
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27
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Lamb RG, Foster K, McGuffin M. A distinction in vitro between rat liver phosphatidate phosphatase and phospholipase C. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 921:67-74. [PMID: 3040107 DOI: 10.1016/0005-2760(87)90171-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hepatocellular membranes (1000 X g) containing membrane-associated, labeled phosphatidic acid were incubated (1-30 min) with 2 mM oleate or 5 mM bromobenzene in the presence or absence of various metals and NaF. Under the appropriate incubation conditions, membranes displayed rapid and significant oleate- and bromobenzene-dependent increases in the dephosphorylation of labeled phosphatidic acid. However, oleate and bromobenzene activated the dephosphorylation of phosphatidate by phosphatidate phosphatase and phospholipase C, respectively. This conclusion is supported by the observation that the phosphatase stimulated by oleate is: (1) Mg2+ -dependent; (2) inhibited by other metals, such as Ca2+; (3) inhibited by NaF; (4) specific for phosphatidic acid; and (5) associated with a rise in liver cell triacylglycerol production. Bromobenzene, however, activated a phospholipase C that is: (1) stimulated by various metals, such as Mg2+, Ca2+ and Ba2+; (2) insensitive to NaF; (3) associated with the degradation of various membrane phospholipids; (4), associated with liver cell injury; and (5) not associated with a rise in liver cell triacylglycerol formation. These results suggest that under appropriate conditions in vitro the dephosphorylation of phosphatidic acid can be used to assess changes in phosphatidate phosphatase and/or phospholipase C activity. The distinction between these enzymes is important, since phosphatidate phosphatase and phospholipase C regulate key steps in phospholipid biosynthesis and degradation, respectively.
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28
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D'Alessandro A, Southard JH, Kalayoglu M, Belzer FO. Effect of drug treatment on liver-slice function following 72-hour hypothermic perfusion. Cryobiology 1986; 23:415-21. [PMID: 3490354 DOI: 10.1016/0011-2240(86)90026-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The viability of hypothermically perfused dog liver was evaluated with a tissue-slice technique. After being preserved for 72 hr, slices of liver were incubated at 30 degrees C for as long as 2 hr; then water content, K+/Na+ ratio, and ATP concentration were measured. Dog livers were assigned to the following experimental groups: Group 1 (no preservation; control); Group 2 (livers preserved for 72 hr); Group 3 (donor animals pretreated with 3.5 mg/kg of chlorpromazine (CPZ) and 20 mg/kg of methylprednisolone (MP), and livers preserved for 72 hr); Group 4 (livers pretreated with 2-deoxycoformycin (2-DOC), 50 mg/liter, and preserved for 72 hr); and Group 5 (combination of Group 3 and Group 4 treatments). Livers in Groups 2, 3, and 4 lost K+ during preservation, and the mean K+/Na+ ratio significantly decreased from a control value of 4.2 +/- 0.4 to 1.5-1.9 (P less than 0.05). Group 5 livers did not lose K+; mean K+/Na+ ratio was 3.9 +/- 0.5. Fresh livers (no preservation) rapidly reaccumulated K+ when the tissue slices were incubated for 2 hr at 30 degrees C; mean K+/Na+ ratio was 3.7 +/- 0.5. Tissue slices from Group 2 livers (72 hr preservation), and livers pretreated with CPZ-MP (Group 3) or pretreated with 2-DOC (Group 4) did not significantly reaccumulate K+ at 30 degrees C; mean K+/Na+ ratio was 1.7-2.1. Only slices prepared from liver pretreated with both CPZ-MP and 2-DOC reaccumulated K+; mean K+/Na+ ratio was 4.6 +/- 1.2.(ABSTRACT TRUNCATED AT 250 WORDS)
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