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Savoca M, Takemoto K, Hu J, Li L, Jacob Kendrick B, Zhong Z, Lemasters JJ. MitoTracker Red for isolation of zone-specific hepatocytes and characterization of hepatic sublobular metabolism. Biochem Biophys Res Commun 2024; 735:150457. [PMID: 39146811 DOI: 10.1016/j.bbrc.2024.150457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/22/2024] [Accepted: 07/25/2024] [Indexed: 08/17/2024]
Abstract
BACKGROUND The liver lobule is divided into three zones or regions: periportal (PP or Zone 1) that is highly oxidative and active in ureagenesis, pericentral (PC or Zone 3) that is more glycolytic, and midzonal (MZ or Zone 2) with intermediate characteristics. AIM Our goal was to isolate and metabolically characterize hepatocytes from specific sublobular zones. METHODS Mice were administered rhodamine123 (Rh123) or MitoTracker Red (MTR) prior to intravital imaging, liver fixation, or hepatocyte isolation. After in vivo MTR, hepatocytes were isolated and sorted based on MTR fluorescence intensity. Alternatively, E-cadherin (Ecad) and cytochrome P450 2E1 (CYP2E1) immunolabeling was performed in fixed liver slices. Ecad and CYP2E1 gene expression in sorted hepatocytes was assessed by qPCR. Oxygen consumption rates (OCR) of sorted hepatocytes were also assessed. RESULTS Multiphoton microscopy showed Rh123 and MTR fluorescence distributed zonally, decreasing from PP to PC in a flow-dependent fashion. In liver cross-sections, Ecad was expressed periportally and CYP2E1 pericentrally in association with high and low MTR labeling, respectively. Based on MTR fluorescence, hepatocytes were sorted into PP, MZ, and PC populations with PP and PC hepatocytes enriched in Ecad and CYP2E1, respectively. OCR of PP hepatocytes was ∼4 times that of PC hepatocytes. CONCLUSIONS MTR treatment in vivo delineates sublobular hepatic zones and can be used to sort hepatocytes zonally. PP hepatocytes have substantially greater OCR compared to PC and MZ. The results also indicate a sharp midzonal demarcation between hepatocytes with PP characteristics (Ecad) and those with PC features (CYP2E1). This new method to sort hepatocytes in a zone-specific fashion holds the potential to shed light on sublobular hepatocyte metabolism and regulatory pathways in health and disease.
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Affiliation(s)
- Matthew Savoca
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Kenji Takemoto
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jiangting Hu
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Li Li
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - B Jacob Kendrick
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Darby Children's Research Institute, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Zhi Zhong
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - John J Lemasters
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA; Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA.
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Zhong Z, Lemasters JJ. A Unifying Hypothesis Linking Hepatic Adaptations for Ethanol Metabolism to the Proinflammatory and Profibrotic Events of Alcoholic Liver Disease. Alcohol Clin Exp Res 2018; 42:2072-2089. [PMID: 30132924 PMCID: PMC6214771 DOI: 10.1111/acer.13877] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/13/2018] [Indexed: 02/06/2023]
Abstract
The pathogenesis of alcoholic liver disease (ALD) remains poorly understood but is likely a multihit pathophysiological process. Here, we propose a hypothesis of how early mitochondrial adaptations for alcohol metabolism lead to ALD pathogenesis. Acutely, ethanol (EtOH) feeding causes a near doubling of hepatic EtOH metabolism and oxygen consumption within 2 to 3 hours. This swift increase in alcohol metabolism (SIAM) is an adaptive response to hasten metabolic elimination of both EtOH and its more toxic metabolite, acetaldehyde (AcAld). In association with SIAM, EtOH causes widespread hepatic mitochondrial depolarization (mtDepo), which stimulates oxygen consumption. In parallel, voltage-dependent anion channels (VDAC) in the mitochondrial outer membrane close. Together, VDAC closure and respiratory stimulation promote selective and more rapid oxidation of EtOH first to AcAld in the cytosol and then to nontoxic acetate in mitochondria, since membrane-permeant AcAld does not require VDAC to enter mitochondria. VDAC closure also inhibits mitochondrial fatty acid oxidation and ATP release, promoting steatosis and a decrease in cytosolic ATP. After acute EtOH, these changes revert as EtOH is eliminated with little hepatocellular cytolethality. mtDepo also stimulates mitochondrial autophagy (mitophagy). After chronic high EtOH exposure, the capacity to process depolarized mitochondria by mitophagy becomes compromised, leading to intra- and extracellular release of damaged mitochondria, mitophagosomes, and/or autolysosomes containing mitochondrial damage-associated molecular pattern (mtDAMP) molecules. mtDAMPs cause inflammasome activation and promote inflammatory and profibrogenic responses, causing hepatitis and fibrosis. We propose that persistence of mitochondrial responses to EtOH metabolism becomes a tipping point, which links initial adaptive EtOH metabolism to maladaptive changes initiating onset and progression of ALD.
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Affiliation(s)
- Zhi Zhong
- Department of Drug Discovery & Biomedical Sciences and
| | - John J. Lemasters
- Department of Drug Discovery & Biomedical Sciences and
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
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3
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Carini R, De Cesaris MG, Spendore R, Albano E. Ethanol potentiates hypoxic liver injury: role of hepatocyte Na(+) overload. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1502:508-14. [PMID: 11068192 DOI: 10.1016/s0925-4439(00)00075-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Centrilobular hypoxia has been suggested to contribute to hepatic damage caused by alcohol intoxication. However, the mechanisms involved are still poorly understood. We have investigated whether alterations of Na(+) homeostasis might account for ethanol-mediated increase in hepatocyte sensitivity to hypoxia. Addition of ethanol (100 mmol/l) to isolated rat hepatocytes incubated under nitrogen atmosphere greatly stimulated cell death. An increase in intracellular Na(+) levels preceded cell killing and Na(+) levels in hepatocytes exposed to the combination of ethanol and hypoxia were almost twice those in hypoxic cells without ethanol. Na(+) increase was also observed in hepatocytes incubated with ethanol in oxygenated buffer. Ethanol addition significantly lowered hepatocyte pH. Inhibiting ethanol and acetaldehyde oxidation with, respectively, 4-methylpyrazole and cyanamide prevented this effect. 4-methylpyrazole, cyanamide as well as hepatocyte incubation in a HCO(3)(-)-free buffer or in the presence of Na(+)/H(+) exchanger blocker 5-(N,N-dimethyl)-amiloride also reduced Na(+) influx in ethanol-treated hepatocytes. 4-methylpyrazole and cyanamide similarly prevented ethanol-stimulated Na(+) accumulation and hepatocyte killing during hypoxia. Moreover, ethanol-induced Na(+) influx caused cytotoxicity in hepatocytes pre-treated with Na(+), K(+)-ATPase inhibitor ouabain. Also in this condition 4-methylpyrazole and 5-(N,N-dimethyl)-amiloride decreased cell killing. These results indicate that ethanol can promotes cytotoxicity in hypoxic hepatocytes by enhancing Na(+) accumulation.
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Affiliation(s)
- R Carini
- Department of Medical Science, University 'A. Avogadro' of East Piedmont, Via Solaroli 17, 27100, Novara, Italy
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Horie Y, Kato S, Ohki E, Tamai H, Yamagishi Y, Ishii H. Hepatic Microvascular Dysfunction in Endotoxemic Rats After Acute Ethanol Administration. Alcohol Clin Exp Res 2000. [DOI: 10.1111/j.1530-0277.2000.tb02041.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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5
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Oshita M, Takei Y, Kawano S, Hijioka T, Masuda E, Goto M, Nishimura Y, Nagai H, Iio S, Tsuji S. Endogenous nitric oxide attenuates ethanol-induced perturbation of hepatic circulation in the isolated perfused rat liver. Hepatology 1994; 20:961-5. [PMID: 7927238 DOI: 10.1002/hep.1840200427] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The purpose of this study was to clarify the role of endogenous nitric oxide in ethanol-induced perturbation of microcirculation and hepatic injury in perfused rat liver. Infusion of ethanol into the portal vein at 25 and 100 mmol/L increased portal pressure, which is an indicator of hepatic vasoconstriction, in a concentration-dependent fashion. Portal pressure started to rise immediately after ethanol load, then decreased gradually and remained at higher than basal levels throughout the period of ethanol infusion. Release of lactate dehydrogenase into the effluent perfusate began to increase after 30 min of ethanol infusion and continued to increase during the 60-min period of ethanol infusion. The lactate dehydrogenase level in the effluent perfusate at 60 min was dependent on the ethanol concentration (0 mmol/L, 8 +/- 3 IU/L; 25 mmol/L, 16 +/- 2 IU/L; 100 mmol/L, 52 +/- 6 IU/L). Simultaneous infusion of NG-monomethyl-L-arginine, a nitric oxide synthesis inhibitor, enhanced significantly the ethanol-induced increase in portal pressure by 100% to 400% and increased lactate dehydrogenase release by 40% to 80%. The effect of NG-monomethyl-L-arginine on the ethanol-induced increase in portal pressure was completely reversed by the co-infusion of an excess dose of L-arginine. Change in portal pressure averaged over 60 min of ethanol infusion correlated with levels of lactate dehydrogenase release 60 min after the initiation of ethanol infusion (r = 0.77, p < 0.01). In conclusion, inhibition of the action of endogenous nitric oxide was associated with an increase in hepatic vasoconstriction and hepatocellular damage.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Oshita
- First Department of Medicine, Osaka University Medical School, Japan
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Oshita M, Sato N, Yoshihara H, Takei Y, Hijioka T, Fukui H, Goto M, Matsunaga T, Kashiwagi T, Kawano S. Ethanol-induced vasoconstriction causes focal hepatocellular injury in the isolated perfused rat liver. Hepatology 1992; 16:1007-13. [PMID: 1398480 DOI: 10.1002/hep.1840160425] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The role of microcirculation in the pathogenesis of alcoholic liver injury was investigated in isolated perfused livers from fed rats. Infusion of ethanol into the portal vein at concentrations ranging from 25 to 200 mmol/L increased portal pressure, which is an indicator of hepatic vasoconstriction, in a concentration-dependent fashion. Portal pressure started to rise immediately on initiation of ethanol load and remained at higher than basal levels throughout the period of ethanol infusion. Release of lactate dehydrogenase, an indicator of cell injury, into the effluent perfusate began to increase after 20 to 30 min of ethanol infusion and continued to increase until the end of the experiment (60 min after the initiation of ethanol infusion). The lactate dehydrogenase level in the effluent perfusate at 60 min was dependent on the ethanol concentration (0 mmol/L, 8 +/- 3 IU/L; 25 mmol/L, 22 +/- 3 IU/L; 50 mmol/L, 51 +/- 11 IU/L; 100 mmol/L, 60 +/- 7 IU/L; 200 mmol/L, 120 +/- 7 IU/L). Simultaneous infusion of sodium nitroprusside (100 mumol/L), a known vasodilator, inhibited significantly the ethanol-induced increases in portal pressure and lactate dehydrogenase release by abolishing hepatic vasoconstriction. In histological examinations focal hepatocellular necrosis, evidenced by trypan blue staining of cell nuclei, was detected predominantly in midzonal and pericentral areas of the liver lobule after 60 min of ethanol infusion. Change in portal pressure during 60 min of ethanol infusion correlated significantly with levels of lactate dehydrogenase after ethanol infusion (r = 0.82; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Oshita
- First Department of Medicine, Osaka University Medical School, Japan
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Orrego H, Carmichael FJ. Effects of alcohol on liver haemodynamics in the presence and absence of liver disease. J Gastroenterol Hepatol 1992; 7:70-89. [PMID: 1543873 DOI: 10.1111/j.1440-1746.1992.tb00939.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- H Orrego
- Department of Medicine, University of Toronto, Ontario, Canada
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8
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Piasecki C, Seifalian AM. Continuous intraoperative monitoring of hepatic blood perfusion using a noninvasive surface electrode. Dig Dis Sci 1990; 35:399-405. [PMID: 2137770 DOI: 10.1007/bf01537421] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Continuous noninvasive measurement of local blood flow at one or more chosen sites will be useful during experiments on the liver, during liver surgery, or after hepatic transplantation. We have compared a Clark-type flow-dependent oxygen electrode having a 3-mm-diameter cathode applied to the surface of rabbit liver to an electromagnetic flowmeter (EMF) on the portal vein. Reduction in portal flow (ranging from 4 to 100% and maintained over 2 min), correlated with reduction in electrode output (r = 0.944, P less than 0.001). Electrode output was independent of systemic arterial PO2 (ranging from 85 to 340 mm Hg) (P greater than 0.99) and thus of oxygen in inspired gases. These results indicate that this electrode gives a continuous indication of portal venous inflow when hepatic central inflow is undisturbed and may thus prove to be a useful tool in the clinical assessment of liver perfusion.
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Affiliation(s)
- C Piasecki
- Department of Anatomy, Royal Free Hospital School of Medicine, London, England
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9
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Costa AK, Trudell JR. Interaction of hypoxia and carbon tetrachloride toxicity in hepatocyte monolayers. Exp Mol Pathol 1989; 50:183-92. [PMID: 2707381 DOI: 10.1016/0014-4800(89)90029-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The toxicity of carbon tetrachloride (CCl4) in monolayer cultures of primary hepatocytes was investigated at oxygen concentrations that prevail in the liver under conditions that range from normoxia to hypoxia: 0.5, 1, 2, and 20% O2. CCl4 was administered in the vapor phase at concentrations that produce aqueous concentrations at 37 degrees C of 0.4, 2.0, and 4.0 mM. Damage was assayed by leakage of aspartate transaminase and the inclusion of Trypan Blue immediately after the 2-hr incubation and after an additional 6-hr incubation in 20% O2. Only in the case of 0.5% O2 and 4 mM CCl4 were the monolayers damaged (18%) immediately after the 2-hr exposure; all other exposed cells were undamaged at that time point and the dose response of cell death as a function of CCl4 and oxygen concentration was not evident until the 6-hr time point. The monolayers exposed to 4 mM CCl4 and 1, 2, or 20% O2 exhibited little immediate damage but were all 100% dead 6 hr later. The monolayers exposed to 2 mM CCl4 and 0.5, 1, 2, or 20% O2 were 53, 48, 40, and 22 +/- 2% dead after 6 hr, respectively. These results suggest that effects of CCl4 exposure, for example alterations in the function or synthesis of essential proteins, require several hours to affect cell viability.
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Affiliation(s)
- A K Costa
- Department of Anesthesia, Stanford University School of Medicine, California 94305-5117
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Affiliation(s)
- J N Benoit
- Department of Physiology and Biophysics, Louisiana State University Medical Center, Shreveport 71130
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Sancho-Tello M, Renau-Piqueras J, Báguena-Cervellera, Guerri C. A biochemical and stereological study of neonatal rat hepatocyte subpopulations. Effect of pre- and postnatal exposure to ethanol. VIRCHOWS ARCHIV. B, CELL PATHOLOGY INCLUDING MOLECULAR PATHOLOGY 1987; 54:170-81. [PMID: 2894091 DOI: 10.1007/bf02899209] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hepatocytes from 12-day-old rats, pre- and post-natally exposed to alcohol, together with those from pair-fed controls, were isolated and subfractionated in six cell subpopulations on Percoll density gradients. These cells were characterized using a combination of biochemical and stereological methods. The low density cells (F2) mainly showed biochemical and stereological features of perivenous hepatocytes, whereas the heavier cells (F6) were primarily periportal hepatocytes. The alcohol-metabolizing enzymes, alcohol dehydrogenase and aldehyde dehydrogenase (high and low Km) showed more activity in the F2 fraction. Alcohol-altered mitochondria and Golgi apparatus occurred mainly in F2 cells, whereas the endoplasmic reticulum and lysosomes appeared to be more altered in the F6 hepatocytes. Alcohol also induced the appearance of some small hepatocytes, with a well-developed rough endoplasmic reticulum and an increased number of mitochondria. Biochemical data indicated that glutamate dehydrogenase and alanine aminotransferase were more affected in F2 cells from alcohol-treated rats, and that the activity of the ethanol-metabolizing enzymes was alos reduced in these hepatocytes. Our results indicate that alcohol exposure during zonal development in the liver could have a selective effect on specific cell components depending on the acinar zone, and that the perivenous hepatocytes appear to be more damaged under these conditions.
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Affiliation(s)
- M Sancho-Tello
- Instituto de Investigaciones Citológicas, Amadeo de Saboya, Valencia, Spain
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Kekonen EM, Jauhonen VP, Hassinen IE. Oxygen and substrate dependence of hepatic cellular respiration: sinusoidal oxygen gradient and effects of ethanol in isolated perfused liver and hepatocytes. J Cell Physiol 1987; 133:119-26. [PMID: 2822730 DOI: 10.1002/jcp.1041330115] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The oxygen dependence of hepatic cellular respiration was studied by employing simultaneous organ spectrophotometry of cytochromes and hemoglobin, the latter used as an intrasinusoidal optical oxygen probe. The Km of cytochrome aa3 for oxygen was found to be 6.8 microM in the isolated perfused liver and 0.3 microM in suspensions of isolated hepatocytes. The results indicate that the sinusoid-to-cell pO2 gradient is about 5 torr. Optical determination of the average effective pO2 indicates that the axial sinusoidal O2 profile does not conform to zero-order O2 uptake in the liver. Because of extensive NAD+ reduction, ethanol increases the thermodynamic driving force of oxidative phosphorylation, and it also increased the oxygen consumption in both the perfused liver and the hepatocyte suspension, but had no effect on the grade of steady-state cytochrome aa3 reduction, the cellular energy state [ATP]/[ADP].[Pi], or the Km of cytochrome aa3 for oxygen. The results indicate that hepatic energy metabolism is oxygen independent at very low O2 concentrations, but that the sinusoidal axial O2 concentration is anomalous, probably due to the spatial arrangement of the metabolizing systems.
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Affiliation(s)
- E M Kekonen
- Department of Medical Biochemistry, University of Oulu, Finland
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Younes M, Strubelt O. Enhancement of hypoxic liver damage by ethanol. Involvement of xanthine oxidase and the role of glycolysis. Biochem Pharmacol 1987; 36:2973-7. [PMID: 3632722 DOI: 10.1016/0006-2952(87)90211-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Using isolated hemoglobin-free perfused rat livers we investigated the hepatotoxic effects of hypoxia, ethanol or the combination of both. Hypoxia only (90 min) led to a weak toxicity as evidenced by the efflux of the enzymes glutamate-pyruvate-transaminase (GPT) and sorbitol dehydrogenase (SDH). This toxic effect was slightly higher in livers treated with ethanol (3 g/l) under normoxic conditions. Ethanol added under hypoxic conditions, however, showed a strong hepatotoxic effect. Under hypoxic conditions, lactate + pyruvate production was increased fivefold over control, indicating that glycolysis was more effectively undergone as main source of energy. Addition of ethanol suppressed this effect, indicating that ethanol inhibited glycolysis. These results indicate that ethanol potentiates hypoxic liver damage by inhibiting the main metabolic pathway yielding ATP under low oxygen tension resulting in a severe energy deficit. Allopurinol (100 mg/l) inhibited the toxic effects seen with ethanol + hypoxia. Also, the inhibitory action of ethanol on glycolysis was antagonized. Our results are consistent with the following model: hypoxia converts NAD-dependent xanthine dehydrogenase (XD) into the oxygen-dependent xanthine oxidase (XO). Due to hypoxia and ethanol, purine metabolites and acetaldehyde accumulate and are metabolized via XO. This process leads to the production of oxygen radicals which most probably mediate both the inhibition of glycolysis and the direct toxic effects towards liver cells.
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Israel Y, Orrego H. Hypermetabolic state, hepatocyte expansion, and liver blood flow: an interaction triad in alcoholic liver injury. Ann N Y Acad Sci 1987; 492:303-23. [PMID: 3300465 DOI: 10.1111/j.1749-6632.1987.tb48683.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Helzberg JH, Brown MS, Smith DJ, Gore JC, Gordon ER. Metabolic state of the rat liver with ethanol: comparison of in vivo 31phosphorus nuclear magnetic resonance spectroscopy with freeze clamp assessment. Hepatology 1987; 7:83-8. [PMID: 3804209 DOI: 10.1002/hep.1840070118] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In vivo 31phosphorus nuclear magnetic resonance spectroscopy was used to measure the hepatic metabolic state in various groups of rats given ethanol, a control liquid diet or a solid chow diet. The use of selective presaturation pulses applied to the broad phosphorus resonances of immobile phospholipids permitted reliable determination of ATP/ADP ratios by quantitation of the ATP-beta and ATP-gamma peak areas. ATP/ADP ratios were depressed by both techniques in rats chronically ingesting ethanol compared to pair-fed animals consuming the control liquid diet. These differences were observed regardless of whether ethanol feeding was continued up to the time of investigation or whether it was discontinued for 24 hr prior to study. Acute alcohol administration in chow-fed rats, not previously ingesting ethanol, did not lower hepatic ATP/ADP ratios by either methodology. In all cases, liver ATP/ADP ratios assessed by 31phosphorus nuclear magnetic resonance spectroscopy were higher than those measured by high-performance liquid chromatography. However, parallel decreases in hepatic ATP/ADP ratios were observed with chronic ethanol consumption by both 31phosphorus nuclear magnetic resonance spectroscopy and the biochemical method, confirming the utility of in vivo 31phosphorus nuclear magnetic resonance spectroscopy for assessment of the hepatic bioenergetic status. The difference in absolute ATP/ADP ratios by the two methods may to some degree be explained by binding effects of ADP with proteins or mitochondrial membranes, rendering it partially invisible to nuclear magnetic resonance or alternatively, by breakdown of high energy phosphate bonds with freeze clamp extraction.
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