1
|
Sharma AK, Kaur J, Kaur T, Singh B, Yadav HN, Pathak D, Singh AP. Ameliorative role of bosentan, an endothelin receptor antagonist, against sodium arsenite-induced renal dysfunction in rats. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:7180-7190. [PMID: 33026618 DOI: 10.1007/s11356-020-11035-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
Arsenic exposure is well documented to cause serious health hazards, such as cardiovascular abnormalities, neurotoxicity and nephrotoxicity. In the present study, we intended to explore the role of bosentan, an endothelial receptor antagonist, against sodium arsenite-induced nephrotoxicity and hepatotoxicity in rats. Sodium arsenite (5 mg/kg, oral) was administered for 4 weeks to induce renal dysfunction in rats. Sodium arsenite intoxicated rats were treated with bosentan (50 and 100 mg/kg, oral) for 4 weeks. Arsenic led renal damage was demonstrated by significant increase in serum creatinine, urea, uric acid, potassium, fractional excretion of sodium, microproteinuria and decreased creatinine clearance in rats. Sodium arsenite resulted in marked oxidative stress in rat kidneys as indicated by profound increase in lipid peroxides, and superoxide anion generation alongwith decrease in reduced glutathione levels. Hydroxyproline assay highlighted arsenic-induced renal fibrosis in rats. Hematoxylin-eosin staining indicated glomerular and tubular changes in rat kidneys. Picrosirius red staining highlighted collagen deposition in renal tissues of arsenic treated rats. Immunohistological results demonstrated the reduction of renal eNOS expression in arsenic treated rats. Notably, treatment with bosentan attenuated arsenic-induced renal damage and resisted arsenic-led reduction in renal eNOS expression. In addition, sodium arsenite-induced alteration in hepatic parameters (serum aspartate aminotransferase, alanine transferase, alkaline phosphatase, bilirubin), oxidative stress and histological changes were abrogated by bosentan treatment in rats. Hence, we conclude that bosentan treatment attenuated sodium arsenite-induced oxidative stress, fibrosis and reduction in renal eNOS expression in rat kidneys. Moreover, bosentan abrogated arsenic led hepatic changes in rats.
Collapse
Affiliation(s)
- Ashwani Kumar Sharma
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, 143005, India
| | - Japneet Kaur
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, 143005, India
| | - Tajpreet Kaur
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, 143005, India
- Department of Pharmacology, Khalsa College of Pharmacy, Amritsar, India
| | - Balbir Singh
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, 143005, India
| | | | - Devendra Pathak
- Department of Veterinary Anatomy, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, India
| | - Amrit Pal Singh
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, 143005, India.
| |
Collapse
|
2
|
Dibra D, Xia X, Mitra A, Cutrera JJ, Lozano G, Li S. Mutant p53 in concert with an interleukin-27 receptor alpha deficiency causes spontaneous liver inflammation, fibrosis, and steatosis in mice. Hepatology 2016; 63:1000-12. [PMID: 26637970 PMCID: PMC4764463 DOI: 10.1002/hep.28379] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 11/17/2015] [Indexed: 12/25/2022]
Abstract
UNLABELLED The cellular and molecular etiology of unresolved chronic liver inflammation remains obscure. Whereas mutant p53 has gain-of-function properties in tumors, the role of this protein in liver inflammation is unknown. Herein, mutant p53(R172H) is mechanistically linked to spontaneous and sustained liver inflammation and steatosis when combined with the absence of interleukin-27 (IL27) signaling (IL27RA), resembling the phenotype observed in nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) patients. Indeed, these mice develop, with age, hepatocyte necrosis, immune cell infiltration, fibrosis, and micro- and macrosteatosis; however, these phenotypes are absent in mutant p53(R172H) or IL27RA(-/-) mice. Mechanistically, endothelin A receptor (ETAR)-positive macrophages are highly accumulated in the inflamed liver, and chemical inhibition of ETAR signaling reverses the observed phenotype and negatively regulates mutant p53 levels in macrophages. CONCLUSION The combination of mutant p53 and IL27RA(-/-) causes spontaneous liver inflammation, steatosis, and fibrosis in vivo, whereas either gene alone in vivo has no effects on the liver.
Collapse
Affiliation(s)
- Denada Dibra
- Department of Pediatrics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030
| | - Xueqing Xia
- Department of Pediatrics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030
| | - Abhisek Mitra
- Department of Pediatrics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030
| | - Jeffry J. Cutrera
- Department of Pediatrics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030
| | - Guillermina Lozano
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030
| | - Shulin Li
- Department of Pediatrics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030,Corresponding author: Shulin Li, PhD, The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, ; Phone: 713-763-9608; Fax: 713-763-9607
| |
Collapse
|
3
|
Schäfer R, Mueller L, Buecheler R, Proksch B, Schwab M, Gleiter CH, Danielyan L. Interplay between endothelin and erythropoietin in astroglia: the role in protection against hypoxia. Int J Mol Sci 2014; 15:2858-75. [PMID: 24557580 PMCID: PMC3958886 DOI: 10.3390/ijms15022858] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Revised: 01/27/2014] [Accepted: 02/13/2014] [Indexed: 12/21/2022] Open
Abstract
We show that, under in vitro conditions, the vulnerability of astroglia to hypoxia is reflected by alterations in endothelin (ET)-1 release and capacity of erythropoietin (EPO) to regulate ET-1 levels. Exposure of cells to 24 h hypoxia did not induce changes in ET-1 release, while 48–72 h hypoxia resulted in increase of ET-1 release from astrocytes that could be abolished by EPO. The endothelin receptor type A (ETA) antagonist BQ123 increased extracellular levels of ET-1 in human fetal astroglial cell line (SV-FHAS). The survival and proliferation of rat primary astrocytes, neural precursors, and neurons upon hypoxic conditions were increased upon administration of BQ123. Hypoxic injury and aging affected the interaction between the EPO and ET systems. Under hypoxia EPO decreased ET-1 release from astrocytes, while ETA receptor blockade enhanced the expression of EPO mRNA and EPO receptor in culture-aged rat astroglia. The blockade of ETA receptor can increase the availability of ET-1 to the ETB receptor and can potentiate the neuroprotective effects of EPO. Thus, the new therapeutic use of combined administration of EPO and ETA receptor antagonists during hypoxia-associated neurodegenerative disorders of the central nervous system (CNS) can be suggested.
Collapse
Affiliation(s)
- Richard Schäfer
- Institute for Transfusion Medicine and Immunohaematology, German Red Cross Blood Donor Service Baden-Württemberg-Hesse gGmbH, Johann-Wolfgang-Goethe-University Hospital, Sandhofstrasse 1, Frankfurt/Main D-60528, Germany.
| | - Lars Mueller
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Auf der Morgenstelle 8, Tuebingen D-72076, Germany.
| | - Reinhild Buecheler
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Auf der Morgenstelle 8, Tuebingen D-72076, Germany.
| | - Barbara Proksch
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Auf der Morgenstelle 8, Tuebingen D-72076, Germany.
| | - Matthias Schwab
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Auf der Morgenstelle 8, Tuebingen D-72076, Germany.
| | - Christoph H Gleiter
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Auf der Morgenstelle 8, Tuebingen D-72076, Germany.
| | - Lusine Danielyan
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Auf der Morgenstelle 8, Tuebingen D-72076, Germany.
| |
Collapse
|
4
|
Stewart RK, Dangi A, Huang C, Murase N, Kimura S, Stolz DB, Wilson GC, Lentsch AB, Gandhi CR. A novel mouse model of depletion of stellate cells clarifies their role in ischemia/reperfusion- and endotoxin-induced acute liver injury. J Hepatol 2014; 60:298-305. [PMID: 24060854 PMCID: PMC4195246 DOI: 10.1016/j.jhep.2013.09.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 08/05/2013] [Accepted: 09/03/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Hepatic stellate cells (HSCs) that express glial fibrillary acidic protein (GFAP) are located between the sinusoidal endothelial cells and hepatocytes. HSCs are activated during liver injury and cause hepatic fibrosis by producing excessive extracellular matrix. HSCs also produce many growth factors, chemokines and cytokines, and thus may play an important role in acute liver injury. However, this function has not been clarified due to unavailability of a model, in which HSCs are depleted from the normal liver. METHODS We treated mice expressing HSV-thymidine kinase under the GFAP promoter (GFAP-Tg) with 3 consecutive (3 days apart) CCl4 (0.16 μl/g; ip) injections to stimulate HSCs to enter the cell cycle and proliferate. This was followed by 10-day ganciclovir (40 μg/g/day; ip) treatment, which is expected to eliminate actively proliferating HSCs. Mice were then subjected to hepatic ischemia/reperfusion (I/R) or endotoxin treatment. RESULTS CCl4/ganciclovir treatment caused depletion of the majority of HSCs (about 64-72%), while the liver recovered from the initial CCl4-induced injury (confirmed by histology, serum ALT and neutrophil infiltration). The magnitude of hepatic injury due to I/R or endotoxemia (determined by histopathology and serum ALT) was lower in HSC-depleted mice. Their hepatic expression of TNF-α, neutrophil chemoattractant CXCL1 and endothelin-A receptor also was significantly lower than the control mice. CONCLUSIONS HSCs play an important role both in I/R- and endotoxin-induced acute hepatocyte injury, with TNF-α and endothelin-1 as important mediators of these effects.
Collapse
Affiliation(s)
- Rachel K. Stewart
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Anil Dangi
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213,Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA
| | - Chao Huang
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Noriko Murase
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Shoko Kimura
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Donna B. Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gregory C. Wilson
- Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA
| | - Alex B. Lentsch
- Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA
| | - Chandrashekhar R. Gandhi
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213,Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA,Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| |
Collapse
|
5
|
Sun MY, Wang L, Mu YP, Liu C, Bian YQ, Wang XN, Liu P. [Effects of Chinese herbal medicine Yinchenhao Decoction on expressions of apoptosis-related genes in dimethylnitrosamine- or carbon tetrachloride-induced liver cirrhosis in rats]. ACTA ACUST UNITED AC 2012; 9:423-34. [PMID: 21486556 DOI: 10.3736/jcim20110412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To investigate the different efficacy of Yinchenhao Decoction (YCHD), a compound traditional Chinese herbal medicine, for liver cirrhosis induced by dimethylnitrosamine (DMN) or carbon tetrachloride (CCl(4)) in rats. METHODS To induce liver fibrosis, 0.5% DMN solution (2mL/kg body weight, i.p.) was given three consecutive days a week to male Wistar rats for 4 weeks. Cirrhotic rats were randomly divided into DMN group, YCHD group, Xiaochaihu decoction group by the end of the fourth week to accomplish a 2-week recipe treatment course. In CCl(4)-induced liver fibrosis model, 50% CCl(4)-olive solution was injected subcutaneously to rats at a dose of 2 mL/kg body weight twice a week to duplicate rat cirrhosis model. After 8 weeks, rats were divided into CCl(4) group, CCl(4) plus YCHD group and Xiaochaihu decoction group. For the YCHD group, YCHD was administered intragastrically once a day for 4 weeks. For DMN or CCl(4) model, by the end of 6 or 12 weeks respectively, rats were sacrificed for sampling to detect liver function, hepatic histological changes, hydroxyproline (Hyp) content and apoptosis-related gene expressions. RESULTS In DMN liver fibrosis model, hepatic fibrosis was obvious at week 2 and cirrhosis was evident at week 4 in DMN-treated rats. Compared to 6-week DMN group, hepatic pathological changes and liver function were improved significantly and content of Hyp decreased remarkably in YCHD group. In CCl(4)-induced liver fibrosis model, hepatic fibrosis was obvious at 8 weeks and cirrhosis was evident at 12 weeks in CCl(4)-treated rats. Compared to 12-week CCl(4) group, hepatic pathological changes and liver function were not obviously improvement in YCHD group. The results of gene chip showed that YCHD significantly decreased Fas, Bax and caspase-3 gene expressions, and increased Bcl-xL gene expression in the liver of DMN model. However, in the model induced by CCl(4), YCHD did not inhibit hepatocyte apoptosis induced by CCl(4), but increased tyrosine kinase receptor gene expression by 4.8 times. CONCLUSION YCHD exerts more significant therapeutic effects on DMN-induced than CCl(4)-induced cirrhosis in rats in Hyp content and pathological change in liver tissue.
Collapse
Affiliation(s)
- Ming-yu Sun
- Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | | | | | | | | | | | | |
Collapse
|
6
|
Abstract
BACKGROUND Endothelin receptor antagonists (ERAs) have recently become prominent therapies for pulmonary arterial hypertension, and are being explored clinically in several areas, including resistant hypertension, idiopathic pulmonary fibrosis, and cancer. OBJECTIVE To review the available preclinical and clinical data surrounding ERAs and their potential role to treat portal hypertension. METHODS A systematic search of peer-reviewed publications was performed using PubMed and Ovid/Medline/EMBASE databases. RESULTS Several preclinical in vivo studies have evaluated ERAs in models of portal hypertension. The majority of these studies employ nonselective ERAs, and support the hypothesis that endothelin participates in the development and maintenance of portal hypertension. A limited number of studies have addressed whether ET(A) receptor-selective ERAs provide an advantage over nonselective agents in ameliorating the effects of portal hypertension, and the majority of these data indicate that selective ERAs may be sufficient. Very few clinical studies have evaluated ERAs in portal hypertension patients. What has been described in humans supports a role for endothelin, but is not sufficient to draw conclusions regarding ERA selectivity. CONCLUSION While preclinical evidence suggests a role for endothelin and ERAs in portal hypertension, scant and equivocal clinical data highlight a need for human studies with current selective and nonselective ERAs.
Collapse
Affiliation(s)
- Kelly R Pitts
- Gilead Sciences Inc., In Vitro Biology, 7575 West 103rd Avenue, Westminster, Colorado 80021, USA.
| |
Collapse
|
7
|
Jameel NM, Thirunavukkarasu C, Wu T, Watkins SC, Friedman SL, Gandhi CR. p38-MAPK- and caspase-3-mediated superoxide-induced apoptosis of rat hepatic stellate cells: reversal by retinoic acid. J Cell Physiol 2008; 218:157-66. [PMID: 18792915 DOI: 10.1002/jcp.21581] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Reactive oxygen species (ROS) activate retinoid-containing quiescent hepatic stellate cells (qHSCs) to retinoid-deficient fibrogenic myofibroblast-like cells (aHSCs). However, ROS also cause apoptosis of aHSCs, and apoptotic aHSCs are observed in inflammatory fibrotic liver. Here, we investigated mechanisms of the effects of oxidative stress on the survival of qHSCs and aHSCs. HSCs from normal rat liver were used after overnight culture (qHSCs), or in 3-5 passages (aHSCs). For in vivo induction of oxidative stress, tert-butylhydroperoxide was injected into control and CCl4-induced cirrhotic rats. Spontaneous caspase-3 activation and apoptosis, observed in cultured qHSCs, decreased with time and were unaffected by superoxide. In contrast, superoxide caused caspase-3 and p38-MAPK activation, reduction in Bcl-xL expression, and apoptosis in aHSCs. Inhibition of caspase-3 and p38-MAPK did not affect the viability of qHSCs in the absence or presence of superoxide, but inhibited superoxide-induced death of aHSCs. Glutathione (GSH) level and activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were lower in aHSCs than qHSCs. Superoxide increased GSH content, and activities of SOD, catalase and GPx in qHSCs but not in aHSCs. Incubation of 13-cis-retinoic acid (RA)-treated aHSCs with superoxide increased their GSH content significantly, and prevented superoxide-induced p38-MAPK and caspase-3 activation while dramatically reducing the extent of apoptosis. Finally, oxidative stress induced in vivo caused apoptosis of aHSCs in cirrhotic but not of qHSCs in control rats. These results suggest that the absence of retinoids render aHSCs susceptible to superoxide-induced apoptosis via caspase-3 and p38-MAPK activation.
Collapse
Affiliation(s)
- Noor Mohamed Jameel
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | | | | | | | | |
Collapse
|
8
|
Du QH, Li PT. Pathophysiology and clinical practice analysis on endothelin system and portal hypertension. Shijie Huaren Xiaohua Zazhi 2008; 16:1092-1097. [DOI: 10.11569/wcjd.v16.i10.1092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Portal hypertension (PHT) is a common clinical syndrome which leads to various severe, even lethal complications. The concentration of endothelin-1 (ET-1) in plasma is increased both in human body and PHT animal model. The effect of ET-1 depends on the kind of tissue and the expression of ET-1 receptor in this tissue. However, the expression of ET-1 receptor is not identical even in the same tissue at different PHT phases. This review aims to give an update on the endothelin syetem in PHT and elucidate a potential novel strategy.
Collapse
|
9
|
Chen Y, Wang CP, Lu YY, Zhou L, Su SH, Jia HJ, Feng YY, Yang YP. Hepatic stellate cells may be potential effectors of platelet activating factor induced portal hypertension. World J Gastroenterol 2008; 14:218-23. [PMID: 18186558 PMCID: PMC2675117 DOI: 10.3748/wjg.14.218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine platelet activating factor (PAF) receptor expression in cirrhotic hepatic stellate cells.
METHODS: Hepatic stellate cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium after overnight culture. We determined the PAF receptor in hepatic stellate cells by saturation binding technique and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and the effects of PAF and its antagonist BN52021 on prostaglandin E2 (PGE2) release by stellate cells.
RESULTS: Scatchard analysis indicated the presence of PAF receptor with dissociation constant (Kd) of 4.66 nmol/L and maximum binding capacity (Bmax) of 24.65 fmol/&mgr;g in cirrhotic stellate cells. Compared with the control, the maximum PAF binding capacity increased significantly (Bmax: 24.65 ± 1.96 fmol/&mgr;g. DNA, R = 0.982 vs 5.74 ± 1.55 fmol/&mgr;g. DNA, R = 0.93; P < 0.01), whereas receptor affinity had no significant difference (Kd of 4.66 ± 0.33 nmol/L for the cirrhosis and 3.51 ± 0.26 nmol/L for the control; P > 0.05). Consistent with the receptor binding data, the mRNA expression of PAF receptor was increased significantly in cirrhotic stellate cells. PAF in a concentration-dependent manner induced PGE2 synthesis in cirrhotic hepatic stellate cells, but the effects were blocked significantly by BN52021.
CONCLUSION: Cirrhosis sensitizes hepatic stellate cells to PAF by elevating its receptor level and hepatic stellate cells maybe potential effectors of PAF induced portal hypertension.
Collapse
|
10
|
Xue H, Guo H, Li YC, Hao ZM. Heme oxygenase-1 induction by hemin protects liver cells from ischemia/reperfusion injury in cirrhotic rats. World J Gastroenterol 2007; 13:5384-90. [PMID: 17879412 PMCID: PMC4171332 DOI: 10.3748/wjg.v13.i40.5384] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the potential protective effect of HO-1 on cirrhotic liver cells in rats.
METHODS: Male Wistar rats included in the current study were randomly divided into 5 groups as follows: normal (N) group; liver cirrhotic (LC) group; sham (S) group; I/R group and I/R + hemin group. The model for inducing liver cirrhosis in rats was established according to a previously published protocol. Following this the segmental hepatic ischemia reperfusion operation was carried out. The rats were treated with 30 μmol/kg hemin (HO-1 inducer, ferric protoporphyrin IX chloride) i.p. or 0.9% NaCl (control) 24 h and 12 h before hepatic ischemia for 30 min or sham laparotomy. Blood was collected for serum enzymatic measurement 6 and 12 h after reperfusion or sham laparotomy. HO-1, NF-κB and caspase-3 expressions were assessed by immunohistochemical analysis.
RESULTS: The expressions of proteins are inversely correlated to the gray values. HO-1 expression in the I/R + hemin group was increased significantly than I/R group at 6 h and 12 h after hepatic I/R (6 h: 112.0 ± 8.3 vs 125.1 ± 5.7, P < 0.01; 12 h: 120.8 ± 11.0 vs 132.4 ± 6.2, P < 0.01). Hemin improved serum manganese superoxide dismutase (MnSOD) (6 h: 131.3 ± 17.6 vs 107.0 ± 13.9, P < 0.01; 12 h: 141.4 ± 12.5 vs 118.3 ± 10.2, P < 0.01), lessened liver cell injury, decreased caspase-3(6 h: 166.7 ± 8.1 vs 145.5 ± 14.6, P < 0.01; 12 h: 172.8 ± 3.8 vs 148.0 ± 6.5, P < 0.01) and NF-κB expression (6 h: 150.2 ± 8.6 vs 139.7 ± 6.0, P < 0.01; 12 h: 151.1 ± 5.9 vs 148.1 ± 5.3, P > 0.05) and serum alanine aminotransferase (ALT) (6 h: 413.3 ± 104.1 vs 626.8 ± 208.2, P < 0.01; 12 h: 322.2 ± 98.8 vs 425.8 ± 115.4, P < 0.05), aspartate aminotransferase (AST) (6 h: 665.2 ± 70.1 vs 864.3 ± 70.4, P < 0.01; 12 h: 531.1 ± 98.6 vs 664.4 ± 115.6, P < 0.01), malondialdehyde (MDA) levels (6 h: 11.1 ± 2.17 vs 13.5 ± 2.01, P < 0.01; 12 h: 9.36 ± 1.10 vs 10.8 ± 1.62, P < 0.05) in the I/R + hemin group when compared with the I/R group.
CONCLUSION: These results suggest that HO-1 plays an important role in protecting liver cells from hepatic I/R injury in cirrhotic rats by decreasing oxidative stress, apoptosis and inflammation.
Collapse
Affiliation(s)
- Hui Xue
- Department of Gastroenterology, The First Affiliated Hospital, Xi'an Jiaotong University Medical College, Xi'an 710061, Shaanxi Province, China.
| | | | | | | |
Collapse
|
11
|
Anselmi K, Stolz DB, Nalesnik M, Watkins SC, Kamath R, Gandhi CR. Gliotoxin causes apoptosis and necrosis of rat Kupffer cells in vitro and in vivo in the absence of oxidative stress: exacerbation by caspase and serine protease inhibition. J Hepatol 2007; 47:103-13. [PMID: 17466404 PMCID: PMC2764960 DOI: 10.1016/j.jhep.2007.02.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 02/12/2007] [Accepted: 02/22/2007] [Indexed: 12/18/2022]
Abstract
BACKGROUND/AIMS A potential application of gliotoxin therapy for liver fibrosis was suggested by its apoptotic effect on fibrogenic activated stellate cells. We investigated if gliotoxin exerts similar effects on hepatic macrophage Kupffer cells. METHODS Effects of gliotoxin on Kupffer cells isolated from the normal liver and in vivo following its administration to CCl(4)-induced cirrhotic rats were studied. RESULTS Gliotoxin caused apoptosis of cultured Kupffer cells, the effect being apparent at 0.3 microM concentration within 1h; longer incubation caused necrosis. This effect was associated with mitochondrial cytochrome c release, caspase-3 activation and ATP depletion. Interestingly, inhibition of caspase-3 and serine proteases accelerated and augmented gliotoxin-induced cell death via necrosis. Gliotoxin stimulated nuclear translocation of NFkappaB, and phosphorylation of p38, ERK1/2 and JNK MAP kinases, but these signaling molecules were not involved in gliotoxin-induced death of Kupffer cells. In vivo administration of gliotoxin to cirrhotic rats caused apoptosis of Kupffer cells, stellate cells and hepatocytes. In control rats, the effect was minimal on the nonparenchymal cells and not apparent on hepatocytes. CONCLUSIONS In the fibrotic liver, gliotoxin nonspecifically causes death of hepatic cell types. Modification of gliotoxin molecule may be necessary for selective targeting and elimination of activated stellate cells.
Collapse
Affiliation(s)
- Kristin Anselmi
- Thomas E. Starzl Transplantation Institute, Department of Surgery, and VA medical Center, University of Pittsburgh, E-1518 BST, 200 Lothrop Street, Pittsburgh, PA 15213, USA
| | | | | | | | | | | |
Collapse
|
12
|
Khurana S, Mukhopadhyay A. Characterization of the Potential Subpopulation of Bone Marrow Cells Involved in the Repair of Injured Liver Tissue. Stem Cells 2007; 25:1439-47. [PMID: 17379762 DOI: 10.1634/stemcells.2006-0656] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In vitro and in vivo studies have shown that bone marrow (BM) stem cells can differentiate into hepatocytes. However, it is not known whether such a differentiation event occurs during normal liver regeneration process. We investigated the role of endogenous BM cells in liver regeneration following acute injury and phenotypically characterized them. We showed that Lin(-)Sca-1(+) cells proliferate in the BM and subsequently mobilize in the peripheral blood in response to liver injury by CCl(4) or an injury simulating condition. In vitro studies confirmed that the damaged liver tissue was capable of inducing migration of a distinct population of BM cells, phenotypically characterized as Lin(-)CXCR4(+)OSMRbeta(+), which can differentiate into albumin and cytoketarin-18 expressing cells. In order to study the migration of BM cells to the regenerating liver, the hematopoietic system was reconstituted with green fluorescent protein (GFP)(+) BM cells by intra-bone marrow transplantation prior to liver damage. The BM-derived cells were found to express hepatocyte-specific genes and proteins in the regenerating liver. Quantitative polymerase chain reaction analysis for a recipient specific gene (sry) in sorted GFP(+)Alb(+) donor cells suggested that fusion was a rare event in this experimental model. In conclusion, we first demonstrated the potential phenotype of BM cells involved in regeneration of liver from acute injury, primarily by the process of direct differentiation. Disclosure of potential conflicts of interest is found at the end of this article.
Collapse
Affiliation(s)
- Satish Khurana
- Stem Cell Biology Laboratory, National Institute of Immunology, New Delhi-110067, India
| | | |
Collapse
|
13
|
Muddu AK, Guha IN, Elsharkawy AM, Mann DA. Resolving fibrosis in the diseased liver: translating the scientific promise to the clinic. Int J Biochem Cell Biol 2006; 39:695-714. [PMID: 17110155 DOI: 10.1016/j.biocel.2006.10.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 10/03/2006] [Accepted: 10/04/2006] [Indexed: 01/18/2023]
Abstract
Liver fibrosis and its end-stage disease cirrhosis are a major cause of mortality and morbidity throughout the world. Fibrosis is a response to chronic liver injury or infection that if unabated leads to the replacement of normal functional liver tissue with scar tissue. Basic research over the past decade has generated a vastly improved knowledge of the cell and molecular biology of liver fibrosis that provides a framework on which to design and develop therapeutics. The field has also witnessed a genuine paradigm shift from the original dogma that liver fibrosis is only ever a progressive process, to the new understanding that liver fibrosis even in an advanced stage can be reversible. There is therefore renewed optimism that liver fibrosis may be cured providing that we develop therapies that halt the fibrogenic process and encourage the natural regenerative properties of the liver. The key to the design of effective therapeutics will be to exploit the ongoing discoveries pertaining to the biology and function of fibrogenic hepatic myofibroblasts and their interplay with other liver cells and with the hepatic extracellular matrix. This review provides a critique of those discoveries in basic research that provide the most promise for translation to the clinic. In addition, we review the latest developments in the search for minimal invasive diagnostic tests for fibrosis that will be essential for determining the efficacy of anti-fibrotic drugs.
Collapse
Affiliation(s)
- Ajay K Muddu
- Liver Group, Division of Infection, Inflammation & Repair, University of Southampton, Southampton SO16 6YD, United Kingdom
| | | | | | | |
Collapse
|
14
|
Budker VG, Subbotin VM, Budker T, Sebestyén MG, Zhang G, Wolff JA. Mechanism of plasmid delivery by hydrodynamic tail vein injection. II. Morphological studies. J Gene Med 2006; 8:874-88. [PMID: 16718734 DOI: 10.1002/jgm.920] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND The efficient delivery of plasmid DNA (pDNA) to hepatocytes by a hydrodynamic tail vein (HTV) procedure has greatly popularized the use of naked nucleic acids. The hydrodynamic process renders onto the tissue increased physical forces in terms of increased pressures and shear forces that could lead to transient or permanent membrane damage. It can also trigger a series of cellular events to seal or reorganize the stretched membrane. Our goal was to study the uptake mechanism by following the morphological changes in the liver and correlate these with the fate of the injected plasmid DNA. METHODS We utilized both light microscopic (LM) and electron microscopic (EM) techniques to determine the effect of the HTV procedure on hepatocytes and non-parenchymal cells at various times after injection. The LM studies used paraffin-embedded livers with hematoxylin and eosin (H&E) staining. The immune-EM studies used antibodies labeled with sub-nanometer gold particles followed by silver enhancement to identify the location of injected pDNA at the subcellular level. The level of overall damage to liver cells was estimated based on alanine aminotransferase (ALT) release and clearance. RESULTS Both the LM and EM results showed the appearance of large vesicles in hepatocytes as early as 5 min post-injection. The number of vesicles decreased by 20-60 min. Plasmid DNA molecules often appeared to be associated with or inside such vesicles. DNA could also be detected in the space of Disse, in the cytoplasm and in nuclei. Non-parenchymal cells also contained DNA, but HTV-induced vesicles could not be observed in them. CONCLUSIONS Our studies suggest an alternative or additional pathway for naked DNA into hepatocytes besides direct entry via membrane pores. It may be difficult to prove which of these pathways lead to gene expression, but the membrane pore hypothesis alone appears insufficient to explain why expression happens preferentially in hepatocytes. Further study is needed to delineate the importance of each of these putative pathways and their interrelationship in enabling oligonucleotide (siRNA) activity and pDNA expression.
Collapse
Affiliation(s)
- Vladimir G Budker
- Department of Pediatrics and Medical Genetics, Waisman Center, University of Wisconsin-Madison, 1500 Highland Ave., Madison, WI 53705, USA
| | | | | | | | | | | |
Collapse
|
15
|
Thirunavukkarasu C, Watkins SC, Gandhi CR. Mechanisms of endotoxin-induced NO, IL-6, and TNF-alpha production in activated rat hepatic stellate cells: role of p38 MAPK. Hepatology 2006; 44:389-98. [PMID: 16871588 DOI: 10.1002/hep.21254] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Compelling experimental evidence indicates that the interactions between endotoxin and hepatic stellate cells (HSCs) can play a significant role in the pathogenesis of liver disease. Endotoxin-induced release of a multifunctional mediator NO (via inducible NO synthase) and the proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-6 by HSCs could be an important mechanism of pathological changes in the liver. However, the signaling mechanisms of these effects are poorly understood. In this study, we found that endotoxin causes activation of mitogen-activated protein kinases (MAPKs) (extracellular signal-regulated protein kinase [ERK] 1 and 2, p38, and c-Jun NH2-terminal kinase [JNK]) and nuclear factor kappaB (NF-kappaB) and production of H(2)O(2) in culture-activated HSCs. However, only p38 and NF-kappaB were found to be responsible for the synthesis of NO, IL-6, and TNF-alpha. Exogenous H(2)O(2) caused modest stimulation of TNF-alpha synthesis, did not affect the synthesis of NO or IL-6, and did not activate NF-kappaB or MAPKs. Inhibition of p38 and NF-kappaB activation by SB203580 and pyrrolidine dithiocarbamate, respectively, blocked endotoxin-induced H(2)O(2), NO, TNF-alpha, and IL-6 synthesis. Inhibition of ERK1/2 and JNK phosphorylation did not alter these effects of endotoxin. Whereas SB203580 inhibited endotoxin-induced NF-kappaB activation, pyrrolidine dithiocarbamate did not affect p38 phosphorylation in endotoxin-stimulated cells. In conclusion, endotoxin-induced synthesis of NO, TNF-alpha, and IL-6 in HSCs is mediated by p38 and NF-kappaB, with involvement of H(2)O(2) in TNF-alpha production.
Collapse
Affiliation(s)
- Chinnasamy Thirunavukkarasu
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | | | | |
Collapse
|
16
|
Fabricio ASC, Rae GA, D'Orléans-Juste P, Souza GEP. Endothelin-1 as a central mediator of LPS-induced fever in rats. Brain Res 2006; 1066:92-100. [PMID: 16360659 DOI: 10.1016/j.brainres.2005.10.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 10/08/2005] [Accepted: 10/14/2005] [Indexed: 11/21/2022]
Abstract
Fever induced by E. coli lipopolysaccharide (LPS) in rats is substantially reduced by blockade of central endothelin ET(B) receptors. This study explores the role of endothelin-1 as a central mediator of fever in rats, by investigating the effect of a pyrogenic dose of LPS on the levels of big endothelin-1 and endothelin-1 in the cerebrospinal fluid (CSF) and endothelin-1 in the plasma. We further assessed whether the increase in body temperature caused by central injection of endothelin-1 constitutes solely a hyperthermia or a true integrated febrile response. LPS (5 mug kg(-1), i.v.) induced fever which peaked at 1.16 +/- 0.24 degrees C within 2 h and remained stable up to 5 h. CSF levels of immunoreactive (ir) big endothelin-1 decreased to undetectable levels at 3 h after LPS, returning only partially at 5 h post-injection. CSF ir-endothelin-1 levels were undetectable in saline-treated animals, but reached 21.9 +/- 5.2 fmol ml(-1) at 3 h after LPS treatment. Plasma ir-endothelin-1 levels were unchanged after saline or LPS. Central injection of endothelin-1 (1 pmol, i.c.v.) caused long-lasting increases in body temperature (0.81 +/- 0.17 degrees C, 3 h), but simultaneously decreased tail skin temperature (-1.10 +/- 0.26 degrees C), indicating cutaneous vasoconstriction. Moreover, endothelin-1 induced fever (1.0 +/- 0.3 degrees C, 3 h) when injected into the preoptic area of the anterior hypothalamus (100 fmol), but not i.v. (1 or 10 pmol). These data suggest that endothelin-1 is produced in the brain and acts centrally as a mediator of LPS-induced fever.
Collapse
Affiliation(s)
- Aline S C Fabricio
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Universidade de São Paulo, 14040-903 Ribeirão Preto, SP, Brazil
| | | | | | | |
Collapse
|
17
|
Yang YP, Ma XM, Wang CP, Han J, Lu YY, Xiang Y, Su SH, Feng YY. Effect of increased hepatic platelet activating factor and its receptor portal hypertension in CCl 4-induced liver cirrhosis. World J Gastroenterol 2006; 12:709-15. [PMID: 16521183 PMCID: PMC4066120 DOI: 10.3748/wjg.v12.i5.709] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the changes in hepatic platelet activating factor (PAF) and its receptors and their effect on portal pressure of cirrhotic rats induced by CCl4.
METHODS: A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCl4 for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique.
RESULTS: Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels (P < 0.01, P < 0.01, P < 0.05, respectively). Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats (P < 0.01). Portal injection of PAF (1 g/kg WT) increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups (54% in control rats and 42% in cirrhotic rats). Injection of the PAF antagonist BN52021 (5 mg/kg WT) decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats.
CONCLUSION: The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in cirrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics.
Collapse
Affiliation(s)
- Yong-Ping Yang
- Department of Gastroenterology, 302 Hospital of the Chinese PLA, Beijing 100039, China.
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Thirunavukkarasu C, Watkins S, Harvey SAK, Gandhi CR. Superoxide-induced apoptosis of activated rat hepatic stellate cells. J Hepatol 2004; 41:567-75. [PMID: 15464236 DOI: 10.1016/j.jhep.2004.06.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 05/19/2004] [Accepted: 06/02/2004] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIMS During liver injury, reactive oxygen species (ROS) are produced by the resident macrophages (Kupffer cells) and infiltrating blood cells such as neutrophils. ROS cause transformation of desmin-positive quiescent hepatic stellate cells (HSCs) into the proliferating activated phenotype that expresses alpha-smooth muscle actin (alpha-SMA). The highly fibrogenic and contractile activated HSCs (aHSCs) produce various cytokines and growth factors, and play important role in the pathophysiology of chronic liver disease. However, apoptotic aHSCs are also observed during active fibrogenesis in the injured liver. Therefore, we investigated the mechanisms of apoptosis of aHSCs in relation to ROS. METHODS HSCs, isolated from normal rat liver, were activated in culture and effects of superoxide were determined between subcultures 3 and 5. RESULTS Treatment with superoxide caused apoptosis of aHSCs as determined by flow cytometry, TUNEL assay and DNA laddering analysis. The mechanisms of superoxide-induced apoptosis involved release of cytochrome c, increased Bax expression, increased caspase-3 activity, and hydrolysis of polyADP-ribose polymerase. Superoxide also increased the expression of antiapoptotic Bcl-xL and nuclear translocation of NFkappaB. Caspase-3 inhibitor (DEVD-fmk) and antioxidants (N-acetylcysteine, vitamin E and superoxide dismutase) inhibited superoxide-induced apoptosis. CONCLUSIONS Superoxide-induced apoptosis of aHSCs may be a novel mechanism of limiting chronic fibrotic liver injury.
Collapse
Affiliation(s)
- Chinnasamy Thirunavukkarasu
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, E-1542 BST, 200 Lothrop street, Pittsburgh, PA 15213, USA
| | | | | | | |
Collapse
|
19
|
Chan CC, Wang SS, Lee FY, Chang FY, Lin HC, Hou MC, Huang HC, Lee SD. Effects of endothelin-1 on portal-systemic collaterals of common bile duct-ligated cirrhotic rats. Eur J Clin Invest 2004; 34:290-6. [PMID: 15086361 DOI: 10.1111/j.1365-2362.2004.01336.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIMS Endothelin-1 (ET-1) may induce intrahepatic vasoconstriction and consequently increase portal pressure. Endothelin-1 has been shown to exert a direct vasoconstrictive effect on the collateral vessels in partially portal vein-ligated rats with a high degree of portal-systemic shunting. This study investigated the collateral vascular responses to ET-1, the receptors in mediation and the regulation of ET-1 action by nitric oxide and prostaglandin in cirrhotic rats with a relatively low degree of portal-systemic shunting. METHODS The portal-systemic collaterals of common bile duct-ligated (BDL) cirrhotic rats were tested by in situ perfusion. The concentration-response curves of collaterals to graded concentrations of ET-1 (10(-10)-10(-7) m) with or without BQ-123 (ET(A) receptor antagonist, 2 x 10(-6) m), BQ-788 (ET(B) receptor antagonist, 10(-7) m) or both were recorded. In addition, the collateral responses to ET-1 with preincubation of N(omega)-nitro-L-arginine (NNA, 10(-4) M), indomethacin (INDO, 10(-5) M) or in combination were assessed. RESULTS Endothelin-1 significantly increased the perfusion pressures of portal-systemic collaterals. The ET-1-induced constrictive effects were inhibited by BQ-123 or BQ-123 plus BQ-788 but not by BQ-788 alone. The inhibitory effect was greater in the combination group. Pretreatment of NNA or NNA plus INDO equivalently enhanced the response of ET-1 while pretreatment of INDO alone exerted no effect. CONCLUSION Endothelin-1 has a direct vasoconstrictive effect on the collaterals of BDL cirrhotic rats, mainly mediated by ET(A) receptor. Endogenous nitric oxide may play an important role in modulating the effects of ET-1 in the portal-systemic collaterals of BDL cirrhotic rats.
Collapse
Affiliation(s)
- C-C Chan
- Taipei Veterans General Hospital, Taipei, Taiwan
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Yang Y, Harvey SAK, Gandhi CR. Kupffer cells are a major source of increased platelet activating factor in the CCl4-induced cirrhotic rat liver. J Hepatol 2003; 39:200-7. [PMID: 12873816 DOI: 10.1016/s0168-8278(03)00229-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND/AIMS Endothelin-1 (ET-1) stimulates the synthesis of platelet-activating factor (PAF) by Kupffer cells in vitro. Hepatic concentrations of both ET-1 (a potent vasoconstrictor) and PAF (a mediator of hepatic vasoconstriction and the cirrhotic hyperdynamic state) increase in cirrhosis. The aim of this study was to determine if the responsiveness of Kupffer cells to produce PAF upon ET-1 challenge is modified by cirrhosis. METHODS Kupffer cells, isolated from the livers of control and CCl(4)-induced cirrhotic rats, were placed in serum-free medium after overnight culture. PAF and ET-1 receptors, ET-1-induced PAF synthesis, and PAF- and ET-1-induced prostaglandin E(2) (PGE(2)) synthesis were determined 24 h later. RESULTS Both basal and ET-1-stimulated PAF synthesis was increased in cirrhotic Kupffer cells as indicated by increased cell-associated and released PAF. Cirrhotic Kupffer cells also had elevated densities of functional receptors for both PAF and ET-1 (exclusively ET(B)), as measured by ligand binding, mRNA expression of the respective receptors, and ligand-stimulated PGE(2) synthesis. CONCLUSIONS Cirrhosis sensitizes Kupffer cells to both ET-1 and PAF by elevating their respective receptor levels. Since both mediators individually cause portal hypertension, an increase in ET-1-stimulated PAF synthesis in Kupffer cells will exacerbate the hepatic and extrahepatic complications of cirrhosis.
Collapse
Affiliation(s)
- Yongping Yang
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, E-1542 BST, 200 Lothrop Street, Pittsburgh, PA 15213, USA
| | | | | |
Collapse
|
21
|
Shao R, Shi Z, Gotwals PJ, Koteliansky VE, George J, Rockey DC. Cell and molecular regulation of endothelin-1 production during hepatic wound healing. Mol Biol Cell 2003; 14:2327-41. [PMID: 12808033 PMCID: PMC194882 DOI: 10.1091/mbc.02-06-0093] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
During hepatic wound healing, activation of key effectors of the wounding response known as stellate cells leads to a multitude of pathological processes, including increased production of endothelin-1 (ET-1). This latter process has been linked to enhanced expression of endothelin-converting enzyme-1 (ECE-1, the enzyme that converts precursor ET-1 to the mature peptide) in activated stellate cells. Herein, we demonstrate up-regulation of 56- and 62-kDa ECE-1 3'-untranslated region (UTR) mRNA binding proteins in stellate cells after liver injury and stellate cell activation. Binding of these proteins was localized to a CC-rich region in the proximal ECE-1 3' UTR base pairs (the 56-kDa protein) and to a region between 60 and 193 base pairs in the ECE-1 3' UTR mRNA (62 kDa). A functional role for the 3' UTR mRNA/protein interaction was established in a series of reporter assays. Additionally, transforming growth factor-beta1, a cytokine integral to wound healing, stimulated ET-1 production. This effect was due to ECE-1 mRNA stabilization and increased ECE-1 expression in stellate cells, which in turn was a result of de novo synthesis of the identified 56- and 62-kDa ECE-1 3' UTR mRNA binding proteins. These data indicate that liver injury and the hepatic wound healing response lead to ECE-1 mRNA stabilization in stellate cells via binding of 56- and 62-kDa proteins, which in turn are regulated by transforming growth factor-beta. The possibility that the same or similar regulatory events are present in other forms of wound healing is raised.
Collapse
Affiliation(s)
- Rong Shao
- Duke University Liver Center, Durham, North Carolina 27710, USA
| | | | | | | | | | | |
Collapse
|
22
|
Chi X, Anselmi K, Watkins S, Gandhi CR. Prevention of cultured rat stellate cell transformation and endothelin-B receptor upregulation by retinoic acid. Br J Pharmacol 2003; 139:765-74. [PMID: 12813000 PMCID: PMC1573899 DOI: 10.1038/sj.bjp.0705303] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
1 Physiologically, perisinusoidal hepatic stellate cells (HSC) are quiescent and store retinoids. During liver injury and in cell culture, HSC transform into proliferating myofibroblast-like cells that express alpha-smooth muscle actin (alpha-sma) and produce excessive amounts of extracellular matrix. During transformation (also known as activation), HSC are depleted of the retinoid stores, and their expression of the endothelin-1 (ET-1) system is increased. ET-1 causes contraction of transformed HSC and is implicated in their proliferation and fibrogenic activity. In order to understand the association between retinoids, ET-1 and the activation of HSC, we investigated the effect of 13-cis-retinoic acid on the transformation of cultured HSC and the expression of ET-1 system. 2 HSC derived from normal rat liver were maintained for 10-12 days in a medium supplemented with 5% serum and containing 2.5 micro M retinoic acid without or with 50 nM ET-1 (ETA+ETB agonist) or sarafotoxin S6c (ETB agonist). In another set of experiments, cells treated for 10-12 days with vehicle (ethanol) or retinoic acid were challenged with ET-1 or sarafotoxin S6c, and various determinations were made at 24 h. 3 Retinoic acid inhibited transformation and proliferation of HSC as assessed by morphological characteristics, expression of alpha-sma, bromodeoxyuridine incorporation and cell count. Retinoic acid also prevented upregulation of ETB receptors without affecting ET-1 or ETA expression. Total protein synthesis ([(3)H]leucine incorporation), collagen alpha types I mRNA expression and collagen synthesis ([(3)H]proline incorporation) were lower in retinoic acid-treated cells. Although ET-1-treated cells were morphologically similar to the control cells, their expression of alpha-smooth muscle actin was significantly inhibited. The presence of retinoic acid in the medium during treatment with ET-1 caused further reduction in the expression of alpha-smooth muscle actin. ET-1 and sarafotoxin S6c stimulated total protein synthesis in vehicle- and retinoic acid-treated cells, but collagen synthesis only in the latter. 4 These results showing prevention of HSC activation and negative regulation of ETB receptor expression in them by retinoic acid may have important pathophysiologic implications.
Collapse
Affiliation(s)
- Xuedong Chi
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, E-1540 BST, 200 Lothrop Street, Pittsburgh, PA 15213, U.S.A
| | - Kristin Anselmi
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, E-1540 BST, 200 Lothrop Street, Pittsburgh, PA 15213, U.S.A
| | - Simon Watkins
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Chandrashekhar R Gandhi
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, E-1540 BST, 200 Lothrop Street, Pittsburgh, PA 15213, U.S.A
- Department of Pathology, Veterans Administration Medical Center, University of Pittsburgh, Pittsburgh, PA, U.S.A
- Author for correspondence:
| |
Collapse
|
23
|
Tsuchiya Y, Suzuki S, Inaba K, Sakaguchi T, Baba S, Miwa M, Konno H, Nakamura S. Impact of endothelin-1 on microcirculatory disturbance after partial hepatectomy under ischemia/reperfusion in thioacetamide-induced cirrhotic rats. J Surg Res 2003; 111:100-8. [PMID: 12842454 DOI: 10.1016/s0022-4804(03)00078-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Endothelin (ET)-1 contributes to hepatic ischemia and reperfusion (HIR) injury in normal liver. This study was conducted to clarify the role of ET-1 in HIR injury in cirrhotic state. MATERIALS AND METHODS Using thioacetamide-induced cirrhotic rats with spontaneous portosystemic shunt, we determined the changes in plasma aspartate aminotransferase (AST) levels, plasma and hepatic ET-1 values, 7-day survival rates, and hepatic oxygen saturation (SO(2)) by time-resolved spectroscopy as an indicator of hepatic microcirculation under intermittent or continuous total hepatic ischemia with subsequent partial hepatectomy. RESULTS Hepatic ET-1 levels in cirrhotic rats were significantly higher than those in noncirrhotic rats. Plasma and hepatic ET-1 levels at 1, 3 and 6 h of reperfusion after intermittent hepatic ischemia were significantly lower than those after continuous hepatic ischemia. In cirrhotic animals subjected to intermittent hepatic ischemia, the elevation of plasma AST levels at 1, 3 and 6 h of reperfusion and the decline in hepatic SO(2) at the end of 60-min hepatic ischemia and after reperfusion were significantly suppressed when compared with those subjected to continuous hepatic ischemia. Pretreatment with a nonselective endothelin receptor antagonist in continuous hepatic ischemia significantly ameliorated plasma AST levels and hepatic SO(2) values with less hepatic sinusoidal congestion, resulting in an improvement in the 7-day survival rate. CONCLUSIONS Continuous hepatic ischemia in the cirrhotic liver has disadvantages relating to microcirculatory derangement with more ET-1 production in partial hepatectomy. In liver surgery, pharmacological regulation of ET-1 production may lead to attenuation of reperfusion injuries for ischemically damaged cirrhotic liver.
Collapse
Affiliation(s)
- Yasuo Tsuchiya
- Second Department of Surgery, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Affiliation(s)
- Don C Rockey
- Department of Medicine and The Liver Center, Duke University Medical Center, Durham, NC 27710, USA.
| |
Collapse
|
25
|
Helmy A, Hayes PC. Contribution of endothelin-1 to the circulatory and renal abnormalities in patients with cirrhosis and portal hypertension. J Pediatr Gastroenterol Nutr 2002; 35:139-43. [PMID: 12187287 DOI: 10.1097/00005176-200208000-00007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
|
26
|
Shao R, Rockey DC. Effects of endothelins on hepatic stellate cell synthesis of endothelin-1 during hepatic wound healing. J Cell Physiol 2002; 191:342-50. [PMID: 12012330 DOI: 10.1002/jcp.10110] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Endothelin-1 production is increased after liver injury and the subsequent wounding response. Further, endothelin-1 has prominent effects on hepatic stellate cells (key effectors of the hepatic wounding response), including on collagen synthesis, proliferation, and expression of smooth muscle proteins. We tested the hypothesis that endothelins (ETs) may regulate endothelin-1 production during hepatic wounding, and have investigated potential mechanisms underlying this process. Studies were performed on isolated stellate cells from normal and injured livers; in addition, potential autocrine effects of ET were assessed in vivo using an ET receptor antagonist in a model of liver injury. In stellate cells isolated from either normal or injured rat livers, ET receptor stimulation with endothelin-3 or sarafotoxin S6C (preferential ET(B) agonists) caused a dose-dependent increase in endothelin-1 production. Additionally, administration of a mixed ET antagonist in vivo during injury led to reduced stellate cell production of endothelin-1. The mechanism by which ETs stimulated endothelin-1 in this system appeared to be through upregulation of ET converting enzyme-1 (which converts precursor ET to mature peptide), rather than by modulation of precursor endothelin-1. We conclude that during liver injury and wound healing, stellate cell endothelin-1 production is, at least partially, stimulated by ETs via autocrine mechanisms that occur at the level of ET converting enzyme-1.
Collapse
Affiliation(s)
- Rong Shao
- Duke University Liver Center, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
| | | |
Collapse
|
27
|
Anselmi K, Subbotin VM, Nemoto E, Gandhi CR. Accelerated reversal of carbon tetrachloride-induced cirrhosis in rats by the endothelin receptor antagonist TAK-044. J Gastroenterol Hepatol 2002; 17:589-97. [PMID: 12084034 DOI: 10.1046/j.1440-1746.2002.02705.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND A multifunctional mediator, endothelin (ET)-1 is implicated in the pathophysiology of liver cirrhosis. Carbon tetrachloride (CCl4)-induced cirrhosis in rats resolves upon termination of CCl4 treatment. We determined the hepatic ET-1 system during such reversal and assessed whether ET-1 receptor antagonism enhances this process. METHODS Cirrhosis was induced in rats by CCl4 treatment for 8 weeks. Treatment with an ETA/ETB antagonist TAK-044 (10 mg/kg per day) was then started and determinations were made at 1, 2 and 4 weeks. RESULTS After termination of CCl4 treatment, accelerated normalization of liver architecture and portal hypertension occurred in TAK-044-treated rats compared with saline-treated rats. The increased hepatic hydroxyproline concentration and collagen I mRNA expression also declined to greater extents in the TAK-044-treated group. Higher collagenase activity in cirrhosis decreased in saline-treated rats, but did not reach basal values. In TAK-044-treated rats, collagenase activity tended to increase at weeks 2 and 4. Increased ET-1 concentration and ETA receptor density declined to normal values in both groups. In contrast, increased ETB receptor density did not change in saline-treated rats, but decreased to control values in TAK-044-treated rats. CONCLUSIONS Our results emphasize the role of ET-1 in chronic liver disease and strongly indicate the potential for ET-1 receptor antagonists in its treatment.
Collapse
Affiliation(s)
- Kristin Anselmi
- Department of Surgery, Thomas E Starzl, Transplantation Institute, University of Pittsburgh, PA 15213, USA
| | | | | | | |
Collapse
|
28
|
Rockey DC. Cellular pathophysiology of portal hypertension and prospects for management with gene therapy. Clin Liver Dis 2001; 5:851-65. [PMID: 11565144 DOI: 10.1016/s1089-3261(05)70195-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In summary, regulation of sinusoidal blood flow in normal and injured liver involves structural, cellular, and humoral components. Available data suggest that stellate cells, resident perisinusoidal mesenchymal cells with a histologic orientation in the sinusoid analogous to [figure: see text] vasoregulatory pericytes, modulate sinusoidal blood flow. This regulation by stellate cells is most evident in the context of liver injury but may apply also to the normal liver. The endothelin and NO systems are important in modulating stellate cell contractility, and their degree of equilibrium is significant in determining the level of local intrahepatic resistance, especially in the injured liver. Manipulation of either or both of these systems is feasible and effective in experimental models. Such findings have obvious clinical implications and are expected to set the [figure: see text] stage for novel gene therapy approaches for treatment of patients with portal hypertension.
Collapse
Affiliation(s)
- D C Rockey
- Departments of Medicine and Cell Biology, Duke University Medical Center, Durham, North Carolina, USA.
| |
Collapse
|
29
|
Kojima H, Sakurai S, Kuriyama S, Yoshiji H, Imazu H, Uemura M, Nakatani Y, Yamao J, Fukui H. Endothelin-1 plays a major role in portal hypertension of biliary cirrhotic rats through endothelin receptor subtype B together with subtype A in vivo. J Hepatol 2001; 34:805-11. [PMID: 11451162 DOI: 10.1016/s0168-8278(01)00045-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS Endothelin-1 has been suggested to play a key role in cirrhotic portal hypertension, but a role of its receptors in vivo is not fully elucidated. METHODS Biliary cirrhosis was induced by bile duct ligation. Expressions of endothelin-1 and its receptors were evaluated by radioimmunoassay and/or reverse-transcription polymerase chain reaction. Hemodynamics were studied using endothelin receptor agonist or antagonist. RESULTS Portal pressure and hepatic endothelin-1 concentrations progressively increased in parallel after bile duct ligation. Gene expression of hepatic prepro-endothelin-1 and endothelin B receptor enhanced after bile duct ligation, while that of endothelin A receptor was unchanged. Intraportal administration of endothelin-1 or endothelin B receptor agonist sarafotoxin 6c (0.5 nmol/kg, respectively) progressively raised portal pressure in both sham and cirrhotic rats. Portal hypertensive effect of sarafotoxin 6c was more intense in cirrhotic rats than sham animals. Neither endothelin A receptor antagonist FR139317 (1 mg/kg) nor endothelin B receptor antagonist BQ788 (1 mg/kg) alone ameliorated cirrhotic portal hypertension. Only the combined endothelin A and B blockade was associated with a decrease in portal pressure in cirrhotic rats. CONCLUSIONS These results indicate that endothelin-1 plays a major role in cirrhotic portal hypertension through endothelin receptor subtype B together with subtype A in vivo.
Collapse
MESH Headings
- Animals
- Azepines/pharmacology
- Blood Pressure
- Endothelin Receptor Antagonists
- Endothelin-1/genetics
- Endothelin-1/physiology
- Endothelins/genetics
- Gene Expression
- Hemodynamics
- Hypertension, Portal/etiology
- Hypertension, Portal/genetics
- Hypertension, Portal/physiopathology
- Indoles/pharmacology
- Liver/physiopathology
- Liver Cirrhosis, Biliary/complications
- Liver Cirrhosis, Biliary/genetics
- Liver Cirrhosis, Biliary/physiopathology
- Oligopeptides/pharmacology
- Piperidines/pharmacology
- Protein Precursors/genetics
- RNA/genetics
- Radioimmunoassay
- Rats
- Receptor, Endothelin A
- Receptor, Endothelin B
- Receptors, Endothelin/genetics
- Receptors, Endothelin/physiology
- Reverse Transcriptase Polymerase Chain Reaction
Collapse
Affiliation(s)
- H Kojima
- Third Department of Internal Medicine, Nara Medical University, Kashihara-shi, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Abstract
Portal hypertension (PHT) is a common clinical syndrome associated with chronic liver diseases; it is characterized by a pathological increase in portal pressure. Pharmacotherapy for PHT is aimed at reducing both intrahepatic vascular tone and elevated splanchnic blood flow. Due to the altered hemodynamic profile in PHT, dramatic changes in mechanical forces, both pressure and flow, may play a pivotal role in controlling endothelial and vascular smooth muscle cell signaling, structure, and function in cirrhotics. Nitric oxide, prostacyclin, endothelial-derived contracting factors, and endothelial-derived hyperpolarizing factor are powerful vasoactive substances released from the endothelium in response to both humoral and mechanical stimuli that can profoundly affect both the function and structure of the underlying vascular smooth muscle. This review will examine the contributory role of hormonal- and mechanical force-induced changes in endothelial function and signaling and the consequence of these changes on the structural and functional response of the underlying vascular smooth muscle. It will focus on the pivotal role of hormonal and mechanical force-induced endothelial release of vasoactive substances in dictating the reactivity of the underlying vascular smooth muscle, i.e., whether hyporeactive or hyperreactive, and will examine the extent to which these substances may exert a protective and/or detrimental influence on the structure of the underlying vascular smooth muscle in both a normal hemodynamic environment and following hemodynamic perturbations typical of PHT and cirrhosis. Finally, it will discuss the intracellular processes that regulate the release/expression of these vasoactive substances and that control the transformation of this normally protective cell to one that may promote the development of vasculopathy in PHT.
Collapse
Affiliation(s)
- P A Cahill
- School of Biotechnology, Dublin City University, Glasnevin Dublin 9, Ireland.
| | | | | |
Collapse
|
31
|
Tièche S, De Gottardi A, Kappeler A, Shaw S, Sägesser H, Zimmermann A, Reichen J. Overexpression of endothelin-1 in bile duct ligated rats: correlation with activation of hepatic stellate cells and portal pressure. J Hepatol 2001; 34:38-45. [PMID: 11211905 DOI: 10.1016/s0168-8278(00)00031-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIMS Hepatic stellate cells (HSC) are involved in the pathogenesis of liver fibrosis; although ET-1 is increased in cirrhosis, its pathophysiological role in fibrogenesis and portal hypertension remains controversial. The aim of this study was to investigate splanchnic hemodynamics and to correlate them with changes in ET-1 expression and HSC activation in bile duct ligated (BDL) rats. METHODS/RESULTS Expression of the ET-1 gene was increased early as measured by quantitative reverse transcriptase-polymerase chain reaction (6-fold 3 days after BDL) whereas ET-1 peptide measured by RIA increased significantly only in the late phase (30-fold at 28 days). There was a linear correlation between portal pressure and the amount of ET-1 in the portal vein (r = 0.66; P = 0.003), as well as between ET-1 and the volume fraction of myofibroblasts (r = 0.80, P < 10(-7)) as assessed by morphometry and immunohistochemical staining using alpha-smooth muscle actin. CONCLUSIONS During chronic liver injury activation of HSCs and of preproET-1 mRNA is accentuated in the early phase after BDL. The late increase in ET-1 peptide may indicate that this peptide is only secondarily involved in HSC activation. The correlation between ET-1 in portal vein and portal pressure suggests that ET-1 may play an important role in the development of portal hypertension.
Collapse
Affiliation(s)
- S Tièche
- Department of Clinical Pharmacology, University of Berne, Switzerland
| | | | | | | | | | | | | |
Collapse
|
32
|
Gandhi CR, Kuddus RH, Nemoto EM, Murase N. Endotoxin treatment causes an upregulation of the endothelin system in the liver: amelioration of increased portal resistance by endothelin receptor antagonism. J Gastroenterol Hepatol 2001; 16:61-9. [PMID: 11206318 DOI: 10.1046/j.1440-1746.2001.02419.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND Mechanisms underlying hepatic microcirculatory failure during endotoxemia are incompletely understood. Because endothelin-1 (ET-1) has been implicated in endotoxin-induced liver injury, we investigated the hepatic ET-1 system in endotoxin-treated rats. METHODS Rats were treated with endotoxin (Escherichia coli lipopolysaccharide; 3 mg/kg, i.p.), and various determinations were made 24 h later. RESULTS Endotoxin treatment caused 11.2 +/- 1.6% weight loss, a decrease in mean arterial pressure (MAP; 96 +/- 5 mmHg vs 108 +/- 3 mmHg; P < 0.05) and an increase in portal pressure (11.6 +/- 1.3 mmHg vs 7.4 +/- 1 mmHg; P < 0.02). No significant changes in the serum levels of liver enzymes or hepatocellular necrosis were observed. Endotoxin caused increases in hepatic ET-1 (from 345 +/- 31 to 565 +/- 38 pg/g; P < 0.01), ET-1 receptor density (from 179 +/- 16 to 340 +/- 26 fmol/mg; P < 0.02), and mRNA expression of preproendothelin-1, and ET(A) and ET(B) receptors. While the serum nitric oxide (nitrite +/- nitrate) concentration was increased in endotoxin-treated rats, that of ET-1 remained unchanged. A mixed ET(A)/ET(B) receptor antagonist, TAK-044 (10 mg/kg, i.v.), reduced the weight loss from 11.2 +/- 1.6% to 5.9 +/- 2.9% (P < 0.05) and the portal pressure from 11.6 +/- 1.3 mmHg to 8.6 +/- 0.7 mmHg (P < 0.05) in endotoxin-treated rats. The mixed ET(A)/ET(B) receptor antagonist also caused an increase in serum ET-1 concentration, but did not affect serum nitric oxide and MAP in endotoxin-treated rats. CONCLUSIONS These results suggest that the upregulated hepatic ET-1 system is an important mechanism of increased portal resistance and related complications of endotoxemia.
Collapse
Affiliation(s)
- C R Gandhi
- Thomas E Starzl Transplantation Institute University of Pittsburgh and Veterans Administration Medical Center Pittsburgh, Pennsylvania 15213, USA.
| | | | | | | |
Collapse
|
33
|
De Gottardi A, Shaw S, Sägesser H, Reichen J. Type A, but not type B, endothelin receptor antagonists significantly decrease portal pressure in portal hypertensive rats. J Hepatol 2000; 33:733-7. [PMID: 11097480 DOI: 10.1016/s0168-8278(00)80303-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND/AIM Endothelin-1 plays an important role in the regulation of portal hypertension; endothelin antagonists have been extensively studied in portal hypertensive animals. We aimed to evaluate the efficacy of highly selective endothelin antagonists in partial portal vein ligated (PPVL) rats. METHODS Four groups of 7 male Sprague-Dawley rats were administered orally ABT-627 (ET(A)-selective), A-192621 (ET(B)-selective), or A-182086 (non-selective), with the fourth group serving as control. On the 3rd day after beginning treatment animals underwent PPVL. On the 11th day hemodynamics were studied and portal vein ET-1 was measured. RESULTS In the control group portal pressure was 13.4+/-SD 0.2 mmHg; this increased to 14.9+/-1.8 (p<0.05) in the ET(B) blocked group. In contrast, ET(A) blockade improved portal hypertension (11.7+/-1.1, p<0.05), while the treatment with the non-selective antagonist had no effect (12.3+/-0.7 n.s.). Mean arterial pressure was not significantly affected by any treatment. Portal vein ET-1 was increased in all groups compared to controls; this increase was limited to the pre-stenotic area (79+/-43 vs 194+/-76 in the pre- and post-stenotic portal vein; p<0.0025). CONCLUSIONS Oral administration of an ET(A) antagonist ameliorated portal hypertension; we suggest that long-term therapy of portal hypertension with selective ET(A) antagonists may be more beneficial than mixed antagonists.
Collapse
Affiliation(s)
- A De Gottardi
- Department of Clinical Pharmacology, University of Berne, Switzerland
| | | | | | | |
Collapse
|
34
|
Kuddus RH, Nalesnik MA, Subbotin VM, Rao AS, Gandhi CR. Enhanced synthesis and reduced metabolism of endothelin-1 (ET-1) by hepatocytes--an important mechanism of increased endogenous levels of ET-1 in liver cirrhosis. J Hepatol 2000; 33:725-32. [PMID: 11097479 DOI: 10.1016/s0168-8278(00)80302-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Hepatic concentration of endothelin-1 (ET-1) is increased in human and experimental liver cirrhosis. Because of its potent actions in the liver, ET-1 has been suggested to play an important role in the pathophysiology of cirrhosis. Since hepatocytes are the major cell type to metabolize ET-1, we investigated whether their reduced capacity to degrade ET-1 is a mechanism of its elevated levels in cirrhosis. METHODS The expression of ET-1 receptors, ET-1 and endothelin converting enzyme (ECE), and metabolism of ET-1 and ECE activity were compared in hepatocytes isolated from control and carbon tetrachloride-induced cirrhotic rats. RESULTS ET-1 receptor density and receptor-mediated internalization of ET-1 were significantly increased in cirrhotic hepatocytes relative to the control cells. However, compared to control hepatocytes, metabolism of ET-1 by the cirrhotic cells was reduced significantly. Interestingly, hepatocytes were found to contain preproET-1 mRNA, ECE-1 mRNA and ET-1. PreproET-1 mRNA and ET-1 levels were increased in cirrhotic hepatocytes but their ECE mRNA and ECE activity were not altered. CONCLUSIONS These results provide the first evidence that hepatocytes have the ability to synthesize ET-1 and demonstrate that decreased metabolism and enhanced synthesis, of ET-1 in hepatocytes are an important mechanism of its elevated levels in cirrhosis.
Collapse
Affiliation(s)
- R H Kuddus
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh and Veterans Administration Medical Center, PA 15213, USA
| | | | | | | | | |
Collapse
|
35
|
Gandhi CR, Kuddus RH, Uemura T, Rao AS. Endothelin stimulates transforming growth factor-beta1 and collagen synthesis in stellate cells from control but not cirrhotic rat liver. Eur J Pharmacol 2000; 406:311-8. [PMID: 11040336 DOI: 10.1016/s0014-2999(00)00683-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Interactions between hepatic stellate cells and endothelin-1 are implicated in liver fibrosis. We determined endothelin-1, its receptors and its effects on the synthesis of a fibrogenic agent transforming growth factor (TGF)-beta1 and collagen in stellate cells from control and CCl(4)-induced cirrhotic rats. The basal synthesis of endothelin-1, TGF-beta1 and collagen was much higher in cirrhotic stellate cells than in control cells. Endothelin-1 stimulated TGF-beta1 and collagen synthesis via endothelin ET(A) and endothelin ET(B) receptors, respectively, in control stellate cells, but did not elicit these effects in the cirrhotic cells despite increased density of the respective receptor subtypes in them. These results indicate that the actions of endothelin-1 on stellate cells may be an important physiological mechanism in maintenance of hepatic architecture. However, inability of endothelin-1 to stimulate TGF-beta1 and collagen synthesis in cirrhotic stellate cells suggests that it does not influence fibrogenic activity by direct action on them probably because the processes are already maximally activated.
Collapse
Affiliation(s)
- C R Gandhi
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, E-1540 BST, 200 Lothrop Street, Pittsburgh, PA 15213, USA.
| | | | | | | |
Collapse
|
36
|
Gandhi CR, Uemura T, Kuddus R. Endotoxin causes up-regulation of endothelin receptors in cultured hepatic stellate cells via nitric oxide-dependent and -independent mechanisms. Br J Pharmacol 2000; 131:319-27. [PMID: 10991926 PMCID: PMC1572329 DOI: 10.1038/sj.bjp.0703577] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2000] [Revised: 07/03/2000] [Accepted: 07/03/2000] [Indexed: 01/14/2023] Open
Abstract
Hepatic stellate cells (HSC) and their transformed phenotype found in the chronically injured liver play important roles in hepatic physiology and pathology. HSC produce and react to a potent contractile peptide endothelin-1 (ET-1) and also synthesize a vasorelaxant nitric oxide (NO) upon stimulation with endotoxin. However, whether endotoxin affects ET-1 system of HSC and if this is a mechanism of endotoxin-induced hepatic injury is not known. We characterized synthesis of ET-1 and NO and ET-1 receptors in cultured quiescent and transformed HSC subjected to endotoxin treatment. Endotoxin (1 - 1000 ng ml(-1)) stimulated synthesis of ET-1 and NO and up-regulated ET-1 receptors in both cell types. Inhibition of NO synthesis by N(G)-monomethyl-L-homoarginine strongly inhibited endotoxin-induced increase in ET-1 receptors in transformed HSC but produced small additional increase in quiescent HSC. Inhibition of soluble guanylyl cyclase by 1H-[1,2, 4]oxadiazolo[4,3-a]quinoxalin-1-one blocked the effect of endotoxin on ET-1 receptors in both cell types. Moreover, ET-1 receptors were increased in both cell types during earlier time points (1 - 4 h) of endotoxin treatment in the absence of the stimulation of NO synthesis. These results demonstrate that endotoxin up-regulates ET-1 receptors in HSC by NO-dependent and -independent mechanisms. Such effects of endotoxin can be of importance in acute endotoxemia and during chronic injury of the liver.
Collapse
Affiliation(s)
- C R Gandhi
- Department of Surgery, University of Pittsburgh, E-1540 BST, 200 Lothrop Street, Pittsburgh, Pennsylvania, PA 15213, USA.
| | | | | |
Collapse
|
37
|
Rothermund L, Leggewie S, Schwarz A, Thöne-Reinecke C, Cho JJ, Bauer C, Paul M, Neumayer HH, Schuppan D, Hocher B. Regulation of the hepatic endothelin system in advanced biliary fibrosis in rats. Clin Chem Lab Med 2000; 38:507-12. [PMID: 10987198 DOI: 10.1515/cclm.2000.074] [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: 11/15/2022]
Abstract
The aim of the present study was to analyze the hepatic endothelin system and its regulation in liver cirrhosis due to bile duct obstruction. Wistar rats were subjected for 6 weeks to: 1) sham operation; 2) bile duct obstruction; 3) bile duct obstruction and the selective oral endothelin A receptor antagonist LU 135252; 4) bile duct obstruction and oral silymarin, a hepatoprotective and antifibrotic compound. We determined tissue concentrations of endothelin-1 and big-endothelin-1 by ELISA and the density of both endothelin receptor subtypes in plasma membrane fractions by Scatchard analysis. The hepatic endothelin system in liver cirrhosis due to chronic bile duct obstruction is characterized by a simultaneous up-regulation of both endothelin-1 tissue concentration (7.2 fold compared to sham operation; p<0.001) as well as the density of both endothelin receptor subtypes (ET(A) 7.4-fold, ET(B) 4.9-fold, p<0.001, respectively) suggesting a synergistic activation of the hepatic endothelin system in this rat model of non-inflammatory cirrhosis. Treatment with proven antifibrotic agents such as silymarin or a selective endothelin-A-receptor blocker (LU 135252) did not reduce the activity of the hepatic endothelin system, suggesting that the hepatic endothelin system is not activated by the fibrotic process itself.
Collapse
Affiliation(s)
- L Rothermund
- Medizinische Klinik mit Schwerpunkt Nephrologie der Charité, Humboldt Universität zu Berlin, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
|
39
|
Kojima H, Yamao J, Tsujimoto T, Uemura M, Takaya A, Fukui H. Mixed endothelin receptor antagonist, SB209670, decreases portal pressure in biliary cirrhotic rats in vivo by reducing portal venous system resistance. J Hepatol 2000; 32:43-50. [PMID: 10673066 DOI: 10.1016/s0168-8278(00)80188-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS This study aimed to evaluate the hemodynamic effects of endothelin-1 or mixed endothelin receptor antagonist, SB209670 in cirrhotic rats, and to elucidate the role of endothelin in cirrhotic portal hypertension. METHODS Secondary biliary cirrhosis was induced by bile duct ligation. Hemodynamics were studied using the radioactive microsphere technique. RESULTS Plasma and hepatic endothelin levels in cirrhotic rats were significantly higher than those in normal rats (plasma, 9.0+/-1.3 vs. 2.6+/-0.5 pg/ml, p<0.001; liver, 74.8+/-13.3 vs. 12.6+/-2.5 pg/g wet tissue, p<0.001). Intraportal administration of endothelin-1 (3 nmol/kg) progressively raised portal pressure without an initial transient reduction, which was observed in systemic arterial pressure, in both cirrhotic and normal rats. SB209670 (5.4 micromol/kg) reduced portal pressure in cirrhotic rats (-19+/-5%, p<0.01) without modifying systemic arterial pressure and renal blood flow, but not in normal rats. This reduction was associated with reduced portal venous system resistance (vehicle, 2.5+/-0.2 vs. SB209670, 1.7+/-0.1 mmHg x min x 100 g bw/ml, p<0.01), but not with change in portal venous inflow and collateral blood flow. CONCLUSIONS Mixed endothelin antagonist, SB209670, decreased portal pressure by reducing portal venous system resistance without modifying systemic arterial pressure and renal blood flow in cirrhotic rats. This result, together with the findings that plasma and hepatic endothelin levels were elevated in cirrhotic rats and that exogenous endothelin-1 increased portal pressure, provides further support for a role of endothelin in portal hypertension and suggests a potential use of mixed endothelin antagonist in the pharmacological treatment of portal hypertension.
Collapse
Affiliation(s)
- H Kojima
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Japan
| | | | | | | | | | | |
Collapse
|
40
|
Gabriel A, Kuddus RH, Rao AS, Gandhi CR. Down-regulation of endothelin receptors by transforming growth factor beta1 in hepatic stellate cells. J Hepatol 1999; 30:440-50. [PMID: 10190727 DOI: 10.1016/s0168-8278(99)80103-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND/AIMS Hepatic endothelin-1 (ET-1) receptor density as well as the levels of both ET-1 and transforming growth factor beta1 (TGF-beta1) increase in liver cirrhosis. Considering their potent contractile (ET-1) and fibrogenic (TGF-beta1) actions on myofibroblastic stellate cells found in the fibrotic/cirrhotic liver, we aimed to investigate the effects of TGF-beta1 on ET-1 receptors and ET-1 synthesis in these cells. METHODS Stellate cells isolated from rat liver by enzymatic digestion were cultured and subjected to TGF-beta1 treatment. Cellular ET-1 receptors and ET-1 released in the medium were determined. RESULTS TGF-beta1 treatment produced time- and dose-dependent decrease in ET-1 binding sites, but did not affect the affinity of the receptors for ET-1. TGF-beta1 also stimulated the release of ET-1 from stellate cells. The extent of TGF-beta1-induced inhibition of [125I]ET-1 binding was much greater for ETB subtype (73+/-18% inhibition), which comprised a major portion (78+/-12%) of the total ET-1 receptors, than for ETA subtype (35+/-11% inhibition). The mRNA expression of the ET-1 receptors also was reduced by TGF-beta1 treatment. TGF-beta1-induced reduction in ET-1 receptor density was coupled to the inhibition of ET-1-stimulated release of [3Hlarachidonic acid from the prelabeled cells. The effects of TGF-beta1 were inhibited by a TGF-beta1 neutralizing monoclonal antibody. CONCLUSIONS These results suggest that the TGF-beta1-induced decrease in ET-1 receptor density may be an important mechanism in limiting the pathologic actions of ET-1 on stellate cells in chronic liver disease.
Collapse
Affiliation(s)
- A Gabriel
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, PA 15213, USA
| | | | | | | |
Collapse
|
41
|
Abstract
Variceal bleeding is a life-threatening complication of cirrhosis. Potential risk factors include clinical, endoscopic, and haemodynamic factors, but why bleeding occurs unpredictably in individual patients is not known. We postulate that bacterial infections in patients with variceal haemorrhage may be the critical factor that triggers bleeding. In patients with large varices and a high wall tension, the release of endotoxin into the systemic circulation during episodes of bacterial infection results in a further increase in portal pressure through the induction of endothelin and possibly vasoconstrictive cyclo-oxygenase products. The subsequent contraction of hepatic stellate cells causes a rise in intrahepatic vascular resistance. Furthermore, endotoxin-induced nitric oxide and prostacyclin, and prostacyclin induced by endothelin could inhibit platelet aggregation, which may result in a further deterioration of primary haemostasis at the level of varix. We propose that the combination of these two effects leads to the onset of variceal haemorrhage.
Collapse
Affiliation(s)
- J Goulis
- Liver Transplantation and Hepatobiliary Medicine, Royal Free Hospital, London, UK
| | | | | |
Collapse
|
42
|
Gabriel A, Kuddus RH, Rao AS, Watkins WD, Gandhi CR. Superoxide-induced changes in endothelin (ET) receptors in hepatic stellate cells. J Hepatol 1998; 29:614-27. [PMID: 9824271 DOI: 10.1016/s0168-8278(98)80157-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Reactive oxygen species are mediators of various pathophysiologic events, including postischemic reperfusion injury and inflammation. Generation of reactive oxygen species and consequent organ injury are associated with increased levels of a powerful vasoconstrictor peptide endothelin-1. Current evidence suggests that actions of endothelin-1 on the contractile and fibrogenic transdifferentiated stellate cells may play a critical role in hepatic pathophysiology. The aim of this investigation was to determine whether reactive oxygen species modulate the synthesis of endothelin-1 and its receptors in stellate cells. METHODS Primary cultures of transdifferentiated stellate cells were exposed to reactive oxygen species-generating system, hypoxanthine/xanthine oxidase, before determination of endothelin-1 and its receptors. RESULTS The treatment caused an initial decrease in ET-1 receptor density (about 30% at 30 min), followed by a significant increase over the basal level at 6 h. The increase in the receptors, which occurred specifically in the ET(B) subtype, progressed thereafter up to 24 h and was accompanied by an augmented functional response, as indicated by an enhanced endothelin-1-induced release of [3H]arachidonic acid from the prelabeled cells. Furthermore, treatment of cells for 24 h but not 30 min caused increased expression of ET(B) mRNA as determined by semi-quantitative polymerase chain reaction. The release of endothelin-1 in the culture medium was also enhanced by hypoxanthine/xanthine oxidase treatment. These effects of hypoxanthine/xanthine oxidase were inhibited by superoxide dismutase and dimethyl sulfoxide. ET-1-induced [3H]arachidonic acid release was also inhibited by the ET(B) receptor antagonist BQ788, but not by the ET(A) receptor antagonist BQ123. CONCLUSIONS These findings indicate that interactions between ET-1 and stellate cells during episodes of the generation of reactive oxygen species can be an important mechanism in the pathophysiology of hepatic disorders.
Collapse
Affiliation(s)
- A Gabriel
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, PA 15213, USA
| | | | | | | | | |
Collapse
|