Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pattern recognition receptors (PRRs) function as sensors of microbial danger signals enabling the vertebrate host to initiate an immune response. PRRs are present not only in immune cells but also in liver parenchymal cells and the complexity of the cell populations provide unique aspects to pathogen recognition and tissue damage in the liver. This review discusses the role of different PRRs in pathogen recognition in the liver, and focuses on the role of PRRs in hepatic inflammation, cholestasis, ischemia, repair and fibrosis. PRRs as novel therapeutic targets are evaluated.
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PMID:Pattern recognition receptors: a contemporary view on liver diseases. 1687 58

This study aimed to examine if T-state stabilization of hemoglobin in erythrocytes could protect against postischemic organ injury. Human erythrocytes containing three different states of Hb allostery were prepared: control Hb (hRBC), CO-Hb that is stabilized under R-state with the 6-coordinated prosthetic heme (CO-hRBC), and alpha-NO-deoxyHb stabilized under T-state (alpha-NO-hRBC). To prepare alpha-NO-RBC, deoxygenated RBC was treated with FK409, a thiol-free NO donor, at its half molar concentration to that of Hb; this procedure resulted in the 5-coordinated NO binding on the alpha-subunit heme, as judged by electron spin resonance spectrometry. Rats were subject to 20 min systemic hemorrhage to maintain mean arterial pressure at 40 mm Hg, and reperfused with one of hRBCs. This protocol for ischemia, followed by 60 min reperfusion with physiological saline, caused modest metabolic acidosis and cholestasis. Administration of hRBC or COhRBC significantly attenuated cholestasis and improved acidosis. Rats treated with alpha-NO-hRBC exhibited greater recovery of metabolic acidosis and bile excretion than those treated with hRBC or CO-hRBC, displaying the best outcome of local oxygen utilization in hepatic lobules. Half-life time of alpha-NO-RBC administered in vivo was approximately 60 min. These results suggest that T-state Hb stabilization by NO serves as a stratagem to treat postischemic organ dysfunction.
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PMID:Erythrocytes with T-state-stabilized hemoglobin as a therapeutic tool for postischemic liver dysfunction. 1698 37

Biliary complications are a major source of morbidity, graft loss, and even mortality after liver transplantation. The most troublesome are the so-called ischemic-type biliary lesions (ITBL), with an incidence varying between 5% and 15%. ITBL is a radiological diagnosis, characterized by intrahepatic strictures and dilatations on a cholangiogram, in the absence of hepatic artery thrombosis. Several risk factors for ITBL have been identified, strongly suggesting a multifactorial origin. The main categories of risk factors for ITBL include ischemia-related injury; immunologically induced injury; and cytotoxic injury, induced by bile salts. However, in many cases no specific risk factor can be identified. Ischemia-related injury comprises prolonged ischemic times and disturbance in blood flow through the peribiliary vascular plexus. Immunological injury is assumed to be a risk factor based on the relationship of ITBL with ABO incompatibility, polymorphism in genes coding for chemokines, and pre-existing immunologically mediated diseases such as primary sclerosing cholangitis and autoimmune hepatitis. The clinical presentation of patients with ITBL is often not specific; symptoms may include fever, abdominal complaints, and increased cholestasis on liver function tests. Diagnosis is made by imaging studies of the bile ducts. Treatment starts with relieving the symptoms of cholestasis and dilatation by endoscopic retrograde cholangiopancreaticography (ERCP) or percutaneous transhepatic cholangiodrainage (PTCD), followed by stenting if possible. Eventually up to 50% of the patients with ITBL will require a retransplantation or may die. In selected patients, a retransplantation can be avoided or delayed by resection of the extra-hepatic bile ducts and construction of a hepaticojejunostomy. More research on the pathogenesis of ITBL is needed before more specific preventive or therapeutic strategies can be developed.
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PMID:Causes and consequences of ischemic-type biliary lesions after liver transplantation. 1713 25

Preservation of the middle hepatic vein (MHV) for a right split liver transplantation (SLT) in an adult recipient is still controversial. The aim of this study was to evaluate the graft and patient outcomes after liver transplantation (LT) using a right split graft, according to the type of venous drainage. From February 2000 to May 2006, 33 patients received 34 cadaveric right split liver grafts. According to the type of recipient pairs (adult/adult or adult/child), the right liver graft was deprived of the MHV or not. The first group (GI, n = 15) included grafts with only the right hepatic vein (RHV) outflow, the second (GII, n = 18) included grafts with both right and MHV outflows. The 2 groups were similar for patient demographics, initial liver disease, and donor characteristics. In GI and GII, graft-to-recipient-weight ratio (GRWR) was 1.2 +/- 0% and 1.6 +/- 0.3% (P < 0.05), and cold ischemia time was 10 hours 55 minutes +/- 2 hours 49 minutes and 10 hours 47 minutes +/- 3 hours 32 minutes, respectively (P = not significant). Postoperative death occurred in 1 patient in each group. Vascular complications included anastomotic strictures: 2 portal vein (PV), 1 hepatic artery (HA), and 1 RHV anastomotic strictures; all in GI. Biliary complications occurred in 20% and 22% of the patients, in GI and GII, respectively (P = not significant). There were no differences between both groups regarding postoperative outcome and blood tests at day 1-15 except for a significantly higher cholestasis in GI. At 1 and 3 yr, patient survival was 94% for both groups and graft survival was 93% for GI and 90% for GII (P = not significant). In conclusion, our results suggest that adult right SLT without the MHV is safe and associated with similar long-term results as compared with those of the right graft including the MHV, despite that early liver function recovered more slowly. Technical refinements in outflow drainage should be evaluated in selected cases.
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PMID:Does middle hepatic vein omission in a right split graft affect the outcome of liver transplantation? A comparative study of right split livers with and without the middle hepatic vein. 1753 13

Death receptor-mediated hepatocyte apoptosis is implicated in a wide range of liver diseases including viral hepatitis, alcoholic hepatitis, ischemia/reperfusion injury, fulminant hepatic failure, cholestatic liver injury, and cancer. Our aim was to clarify the protective pathway in death receptor-mediated hepatocyte apoptosis and the significance of apoptosis in liver injury. In vitro: AdIkappaBsr plus tumor necrosis factor (TNF)-alpha/Jo2 rapidly induced apoptosis in mouse hepatocyte, whereas TNF-alpha/Jo2 alone produced little cytotoxicity. The combination of the mitochondrial permeability transition (MPT) inhibitors, cyclosporine A and trifluoperazine, protected AdIkappaBsr-infected hepatocytes from TNF-alpha- but not Fas-mediated apoptosis. The TNF-alpha and Jo2 induced iNOS through NF-kappaB. Nitric oxide donor (S-nitroso-N-acetylpenicillamine) inhibited Bid cleavage, the MPT, and caspase activation and reduced TNF-alpha- and Fas-mediated cell killing. Inhibition of PI3K by LY294,002 and a dominant-negative Akt, which attenuated NF-kappaB activation by TNF-alpha or Jo2, sensitized hepatocytes to TNF- or Jo2. In vivo: apoptosis as well as necrosis may play an important role in hepatic ischemia/reperfusion injury. Adenoviral gene transfer of myrAkt could inhibit apoptotic cell death and subsequent hepatic ischemia/reperfusion injury in the rat, through Bad not NF-kappaB. Bile acids cause liver injury during cholestasis by inducing hepatocyte apoptosis. Hepatocyte apoptosis has a major role in hepatic injury by bile duct ligation. At least, early hepatic injury by bile duct ligation involved Fas-mediated and Bcl-xL insensitive apoptotic pathway. In conclusion, the role of apoptosis in various liver diseases may suggest possible treatments.
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PMID:Tumor necrosis factor signaling in hepatocyte apoptosis. 1756 63

Cholestatic disorders may arise from liver ischemia (e.g., in liver transplantation) through various mechanisms. We have examined the potential of hypoxia to induce changes in the expression of hepatobiliary transporter genes. In a model of arterial liver ischemia subsequent to complete arterial deprivation of the rat liver, the mRNA levels of VEGF, a hypoxia-inducible gene, were increased fivefold after 24 h. The pattern of VEGF-induced expression and ultrastructural changes, including swelling of the endoplasmic reticulum, indicated that hypoxia affected primarily cholangiocytes, but also hepatocytes, predominantly in the periportal area. Serum and bile analyses demonstrated liver dysfunction of cholestatic type with reduced bile acid biliary excretion. Fluorescence-labeled ursodeoxycholic acid used as a tracer displayed no regurgitation, eliminating bile leakage as a significant mechanism of cholestasis in this model. In liver tissue, a marked reduction in the mRNA levels of Na(+)-taurocholate-cotransporting polypeptide (Ntcp), bile salt export protein (Bsep), and multidrug resistance-associated protein 2 (Mrp2) and an increase in those of Cftr were detected before bile duct proliferation occurred. In cultured hepatocytes, a nontoxic hypoxic treatment caused a decrease in the mRNA and protein expression of Ntcp, Bsep, and Mrp2 and in the mRNA levels of nuclear factors involved in the transactivation of these genes, i.e., HNF4alpha, RXRalpha, and FXR. In bile duct preparations, hypoxic treatment elicited an increase in Cftr transcripts, along with a rise in cAMP, a major regulator of Cftr expression and function. In conclusion, hypoxia triggers a downregulation of hepatocellular transporters, which may contribute to cholestasis, whereas Cftr, which drives secretion in cholangiocytes, is upregulated.
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PMID:Hypoxia-induced changes in the expression of rat hepatobiliary transporter genes. 1761 79

Hepatic ischemia-reperfusion (IR) injury during liver transplantation can lead to cholestasis and remote organ dysfunction. Multidrug resistance-associated proteins (Mrps) are efflux transporters known to transport a diverse set of substrates, such as amphipathic chemicals, organic anions, and endogenous molecules. The purpose of this study was to determine the effect of hepatic IR injury on the expression of Mrps in rat liver and kidney. Male Sprague-Dawley rats were subjected to 60 min of partial hepatic ischemia. At various times after reperfusion (0, 3, 6, 24, and 48 h), the ischemic lobes were harvested as well as kidneys. RNA and protein expression of Mrps in livers and kidneys were determined by the branched DNA method, Western blot analysis, and tissue immunofluorescence. Mrp2 mRNA and protein expression in livers decreased after IR. Conversely, Mrp2 mRNA and protein expression in kidneys increased after IR. Mrp3 mRNA expression, and Mrp4 mRNA and protein expression in kidneys transiently increased after IR. The intensity of immunofluorescent staining of Mrp2 corresponded to changes in Mrp2 expression in livers and kidneys after IR as detected by Western blot analysis and was localized to the apical membrane domain in both tissues. These results demonstrate that after hepatic IR, downregulation of hepatic Mrp2 and upregulation of renal Mrp2 occur. These decreases in hepatic Mrp2 may contribute to cholestasis, yet increases in kidney may protect from oxidative stress and/or inflammation after hepatic IR.
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PMID:Ischemia-reperfusion of rat livers decreases liver and increases kidney multidrug resistance associated protein 2 (Mrp2). 1795 26

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease characterized by mucocutaneous and visceral telangiectasia. Hepatic involvement with vascular malformations may lead to portal hypertension, biliary ischemia, and high-output cardiac failure. Liver transplantation is indicated for life-threatening disease but carries significant risk from surgery and chronic immunosuppression. We report a case of a 47-year-old woman with HHT successfully treated with the vascular endothelial growth factor (VEGF) antibody bevacizumab. The patient was referred for consideration of liver transplantation because of hepatic HHT leading to high-output cardiac failure, diuretic resistant ascites, cholestasis, and malnutrition. As she was considered a high-risk candidate for transplantation, she underwent 6 courses of bevacizumab (5 mg/kg) over 12 weeks. A dramatic improvement in her clinical state was observed after 3 months with reversal of cholestasis, resolution of cardiac failure and ascites, and improvement in nutritional status with a 10% dry weight increase. Treatment induced a marked reduction in liver vascularity and halving of her liver volume from 4807 to 2269 mL over 6 months. This was associated with normalization of her cardiac output from 10.2 to 5.1 L/minute. Correspondingly, she ceased diuretic medications, returned to full-time work, and was delisted as a transplant candidate. She remains well 6 months after completing treatment. In conclusion, antagonism of VEGF receptors led to a dramatic regression of hepatic vascular malformations and reversal of high-output cardiac failure and complications of portal hypertension in this patient with HHT. Bevacizumab may potentially alleviate the need for liver transplantation in this group of patients.
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PMID:Bevacizumab reverses need for liver transplantation in hereditary hemorrhagic telangiectasia. 1897 80

Biochemical cholestasis after liver transplantation is common and often has no clinical significance if biliary anastomosis strictures and leaks have been excluded. There is no agreed upon definition for severe cholestasis, but it is associated with a worse mortality. There has been little evaluation on risk factors, but these include cryoprecipitate and platelet transfusion intraoperatively, nonidentical blood group, suboptimal graft appearance, inpatient status before transplant, and bacteremia within the first month. Associated causes considered as early (<6 months) include ischemia-reperfusion injury, primary nonfunction, small-for-size graft syndrome, infection, drugs and acute cellular rejection. Late causes include hepatic artery thrombosis, chronic rejection, biliary complications, recurrent viral and cholestatic disease, and posttransplant lymphoproliferative disorder.
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PMID:Intrahepatic cholestasis after liver transplantation. 1824

Cholestasis, induced by liver ischemia-reperfusion injury (IRI), is characterized by dilatation of bile canaliculi and loss of microvilli. Tauroursodeoxycholic acid (TUDCA) is an anti-cholestatic agent, modulating protein kinase C (PKC) alpha pathway. PKC reduces ischemic damage in several organs, its isoform alpha modulates ezrin, a key protein in the maintenance of cell lamellipoidal extensions. We evaluated the effects of TUDCA on cholestasis, canalicular changes and PKCalpha-ezrin expression in a rat model of liver IRI. Livers flushed and stored with Belzer solution or Belzer + 10 mm TUDCA (4 degrees C for 6 h) were reperfused (37 degrees C with O(2)) with Krebs-Ringer bicarbonate + 2.5 micromol/min of Taurocholate or TUDCA. Bile was harvested for bile flow assessment. Liver tissue was employed for Electron Microscopy (EM) and for PKCalpha and ezrin immunoblot and immunofluorescence. The same experiments were conducted with the PKCalpha inhibitor Go-6976. TUDCA-treated livers showed increased bile flow (0.25+/-0.17 vs. 0.042+/-0.02 microl/min/g liver, P<0.05) and better preservation of microvilli and bile canalicular area at EM. These effects were associated with increased PKCalpha and ezrin expression (P=0.03 and P=0.04 vs. control respectively), as also confirmed by immunofluorescence data. PKCalpha inhibition abolished these TUDCA effects. TUDCA administration during IRI reduces cholestasis and canalicular damage in the liver modulating PKCalpha-ezrin pathway.
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PMID:TUDCA prevents cholestasis and canalicular damage induced by ischemia-reperfusion injury in the rat, modulating PKCalpha-ezrin pathway. 1843 80


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