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Ronald W Busuttil

Publications and source records attributed to Ronald W Busuttil.

At least 37 records · Page 2Linked to original sources
PubMed2006

Vascular endothelial growth factor antagonist modulates leukocyte trafficking and protects mouse livers against ischemia/reperfusion injury.

Although hypoxia stimulates the expression of vascular endothelial growth factor (VEGF), little is known of the role or mechanism by which VEGF functions after ischemia and reperfusion (I/R) injury. In this report, we first evaluated the expression of VEGF in a mouse model of liver warm ischemia. We found that the expression of VEGF increased after ischemia but peaked between 2 and 6 hours after reperfusion. Mice were treated with a neutralizing anti-mouse VEGF antiserum (anti-VEGF) or control serum daily from day -1 (1 day before the initiation of ischemia). Treatment with anti-VEGF significantly reduced serum glutaminic pyruvic transaminase levels and reduced histological evidence of hepatocellular damage compared with controls. Anti-VEGF also markedly decreased T-cell, macrophage, and neutrophil accumulation within livers and reduced the frequency of intrahepatic apoptotic terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive cells. Moreover, there was a reduction in the expression of pro-inflammatory cytokines (tumor necrosis factor-alpha and interferon-gamma), chemokines (interferon-inducible protein-10 and monocyte chemoattractant protein-1) and adhesion molecules (E-selectin) in parallel with enhanced expression of anti-apoptotic genes (Bcl-2/Bcl-xl and heme oxygenase-1) in anti-VEGF-treated animals. In conclusion, hypoxia-inducible VEGF expression by hepatocytes modulates leukocyte trafficking and leukocyte-induced injury in a mouse liver model of warm I/R injury, demonstrating the importance of endogenous VEGF production in the pathophysiology of hepatic I/R injury.

Animals↗
PubMed2006

The MELD score in advanced liver disease: association with clinical portal hypertension and mortality.

BACKGROUND: The Model for End-Stage Liver Disease (MELD) score is a measure of chronic liver disease severity. Patients awaiting transplantation are assessed using this score. However, it has recently been suggested that changes in MELD score may be as important as the absolute MELD score in predicting short-term survival. However, clinical factors that affect the MELD score are unknown. We sought to identify predictors of mortality for potential transplant patients and examine factors that might predict changes in MELD score. MATERIALS AND METHODS: Between January 1, 2002, and July 30, 2004, we retrospectively examined risk factors of 429 adult patients awaiting liver transplantation at the University of California at Los Angeles (UCLA). Analysis of the data was performed using demographics, manifestations of portal hypertension, time between last MELD recorded and event, and laboratory values. Significant factors in univariate analysis were further studied using Cox proportional hazards regression multivariate analysis. RESULTS: At mean follow-up of 2.15 years (+/-1.49 years), 71 patients (16.5%) had MELD scores that increased 5-10 points, 22 had changes of 10-15 points, and 14 had changes of 15-20 points. Manifestations of portal hypertension, laboratory values, and etiology of liver disease did not predict changes in MELD score. However, development of hepatic encephalopathy (HR, 3.95; P=.002; 95% CI, 1.70 to 9.42) and MELD score (HR, 1.04; P=.001; 95% CI, 1.004 to 1.08) were associated with variceal bleeding. Also, MELD score (HR, 1.07; P<.001; 95% CI, 1.05 to 1.09), refractory ascites (HR, 2.15; P=.002; 95% CI, 1.31 to 3.53), and alcoholic cirrhosis (HR, 0.40; P=.04; 95% CI, 0.18 to 0.94) were independent predictors of mortality. CONCLUSIONS: Encephalopathy and MELD score were associated with variceal bleeding. Patients with an elevated MELD score, refractory ascites, and alcoholic cirrhosis had increased mortality while on the liver transplant list. No factors predicting changes in the MELD score were identified.

Adult↗
PubMed2005

Inhibition of chronic rejection by antibody induced vascular accommodation in fully allogeneic heart allografts.

BACKGROUND: The potential role of altered antibody responses as an effector protective mechanism to induce graft accommodation has been widely investigated in xenogeneic responses. Here we investigate the protective effects of antibody binding to vascular endothelium in a fully mismatched allogeneic model of heart transplantation. METHODS: ACI recipients of WF cardiac grafts were treated either with allochimeric [alpha1h ]-RT1.A class I major histocompatibility complex (MHC) extracts (1 mg/rat, p.v. day 0) or high dose of CsA (10 mg/kg/day, p.o., day 0-6). Cardiac allografts were evaluated at 100 days posttransplant by immunohistology for evidence of chronic rejection and/or vascular accommodation. Activation of apoptotic or antiapoptotic mechanisms was verified by DNA fragmentation (TUNEL) analysis. RESULTS: Allochimeric therapy resulted in inhibition of chronic rejection, absence of neointimal formation and induction of vascular accommodation of fully allogeneic WF hearts in ACI hosts. Such accommodation was evident by IgG and IgM vascular endothelial binding and marked reduction of DNA fragmentation. In contrast, CsA therapy resulted in marked neointimal proliferation, without evidence of vascular accommodation. Immunohistochemical analysis failed to demonstrate vascular endothelial antibody binding. Further, severe chronic rejection following CsA treatment was accompanied by marked DNA fragmentation. CONCLUSION: Alteration of humoral immunity induces vascular accommodation in allogeneic transplantation. Vascular accommodation is the underlying mechanism for inhibition allograft vasculopathy following allochimeric MHC class I therapy.

Animals↗
PubMed2005

Fulminant hepatic failure from primary hepatic lymphoma: successful treatment with orthotopic liver transplantation and chemotherapy.

Systemic lymphomas may involve the liver but rarely cause fulminant hepatic failure (FHF). Acute liver failure from primary hepatic lymphoma (PHL) is even less common with most patients succumbing to the sequelae of FHF before the correct diagnosis is made. We report a patient who underwent successful orthotopic liver transplant (OLT) and chemotherapy for FHF secondary to PHL. This previously-well male developed profound coagulopathy and encephalopathy 6 weeks after the onset of jaundice and fatigue. Workup failed to reveal the underlying cause of his liver failure and the patient soon required urgent OLT. Pathologic evaluation of his explanted liver revealed a malignant T-cell rich, large B-cell non-Hodgkin's lymphoma with widespread hepatocellular necrosis. The patient made an excellent clinical recovery and is undergoing CHOP-Rituxan chemotherapy. This scenario demonstrates that lymphoma should be considered in the differential diagnosis of FHF without clear etiology because of the potential for intervention with transplant and chemotherapy.

Combined Modality Therapy↗
PubMed2005

Disruption of P-selectin signaling modulates cell trafficking and results in improved outcomes after mouse warm intestinal ischemia and reperfusion injury.

BACKGROUND: This study analyzes the role of T lymphocytes and neutrophils (PMN) in intestinal ischemia and reperfusion injury (IRI) using either P-selectin blockade or elimination. METHODS: Using a model of severe mouse warm intestinal IRI, the following groups were performed: group 1: wild type C57BL6 no treatment; group 2: wild type treated with r-PSGL1-Ig; group 3: C57BL6 genetically deficient in P-selectin. Survival was assessed at day 7; intestine was assayed for histopathology, apoptosis, myeloperoxidase (MPO), inflammatory cytokines, hemoxygenase-1 (HO-1), and CD3 lymphocytes. Standard statistical comparison was undertaken. RESULTS: The survival was significantly (P < 0.01) improved in the treatment groups: group 1, 50%; group 2, 90%; group 3, 100%. Graded histopathology and crypt apoptosis were improved in groups 2 and 3. MPO and CD3 positive cells were significantly reduced in groups 2 and 3. A significant reduction in inflammatory/Th1-type cytokines was seen in groups 2 and 3 as compared to group 1. Conversely, a significant increase in Th2-type cytokines and HO-1 production was seen selectively in groups 2 and 3. CONCLUSIONS: This study demonstrates the importance of P-selectin signaling in warm, murine intestinal IRI in that either the blockade of or the genetic deficiency in P-selectin confers a survival advantage and reduction in tissue injury/inflammation. The mechanism involves a reduction of PMN and CD3 T cell infiltration and an alteration in the cytokine microenvironment in favor of a Th2 profile. These data implicate T lymphocyte as an important regulatory cell in this inflammatory process.

Animals↗
PubMed2005

The CD154-CD40 T-cell co-stimulation pathway in liver ischemia and reperfusion inflammatory responses.

BACKGROUND: Ischemia-reperfusion (I/R) injury is a prime antigen-independent inflammatory factor in the dysfunction of liver transplants. The precise contribution of T cells in the mechanism of I/R injury remains to be elucidated. As the CD154-CD40 co-stimulation pathway provides essential second signal in the initiation and maintenance of T-cell-dependent immune responses, this study was designed to assess the role of CD154 signaling in the pathophysiology of liver I/R injury. METHODS: A mouse model of partial 90-min warm hepatic ischemia followed by 6 hr of reperfusion was used. Three animal groups were studied: (1) wild-type (WT) mice treated with Ad-(-gal versus Ad-CD40 immunoglobulin; (2) untreated WT versus CD154 (MR1) monoclonal antibody-treated WT mice; and (3) untreated WT versus CD154 knockout mice. RESULTS: The disruption of CD154 signaling in all three animal groups ameliorated otherwise fulminant liver injury, as evidenced by depressed serum glutamic oxaloacetic transaminase levels, compared with controls. These beneficial effects were accompanied by depressed hepatic T-cell sequestration, local decrease of vascular endothelial growth factor expression, inhibition of tumor necrosis factor-(and T-helper type 1 cytokine production, and induction of antiapoptotic (Bcl-2/Bcl-xl) but depression of proapoptotic (caspase-3) proteins. CONCLUSIONS: By using in parallel a gene therapy approach, pharmacologic blockade, and genetically targeted mice, these findings document the benefits of disrupting CD154 to selectively modulate inflammatory responses in liver I/R injury. This study reinforces the key role of CD154-CD40 T-cell co-stimulation in the pathophysiology of liver I/R injury.

Animals↗
PubMed2005

Infectious enteritis after intestinal transplantation: incidence, timing, and outcome.

BACKGROUND: The study reviews the incidence, timing, and outcome of infectious enteritis (IE) after intestinal transplantation (ITx). METHODS: A retrospective review of all patients who underwent ITx at a single institution between 1991 and 2003 was undertaken using database and medical records. Standard statistical analyses were performed. RESULTS: Of 33 ITx recipients, 13 (39%) developed 20 culture- or biopsy-proven episodes of IE. Recipient demographics included the following: 10 males, median age 34 (10-585) months, 11 liver + intestine grafts, and two isolated intestine grafts. Infections were diagnosed a median of 76 days (32-1,800 days) after ITx. There were 14 viral (one cytomegalovirus, eight rotavirus, four adenovirus, one Epstein-Barr virus), three bacterial (Clostridium difficile), and three protozoal (one Giardia lamblia, two Cryptosporidium) infections. The bacterial infections tended to present earlier than the viral infections, and the most frequent presenting symptom was diarrhea. Complete resolution was achieved in 17 (94%) incidences with the appropriate antimicrobial or conservative therapy. It was interesting that there were seven rejection episodes documented by biopsy at the approximate time of diagnosis of IE. There were two graft losses: one because of adenoviral enteritis and one because of rejection after rotavirus enteritis. Three-year patient survival is 74% with no deaths directly attributable to IE. CONCLUSIONS: IE can occur in 39% of recipients after ITx. Viral agents are the cause in two thirds of the cases. With supportive care and appropriate treatment, resolution is possible in the majority of cases. Differentiating rejection and infection on histopathology can be difficult and relies on cultures and immunostaining.

Adult↗
PubMed2005

Radiofrequency ablation of hepatocellular carcinoma: treatment success as defined by histologic examination of the explanted liver.

PURPOSE: To retrospectively evaluate the effectiveness of radiofrequency (RF) ablation of hepatocellular carcinoma (HCC) by using histologic examination of the explanted liver. MATERIALS AND METHODS: The study was approved by the medical center Institutional Review Board, with waiver of informed consent. Forty-seven HCC nodules in 24 patients (18 men, six women; age range, 33-71 years; mean age, 56 years) were treated with single or double RF ablation sessions prior to liver transplantation. Histologic data from hematoxylin-eosin staining of explanted liver specimens were retrospectively reviewed to determine treatment success, which was defined as the absence of residual or recurrent viable carcinoma cells at treatment site. Tumor size and the presence of large (> or =3 mm) abutting vessels that were observed during imaging were tested as potential predictors of treatment success or failure (Fisher exact test). In patients who underwent postablation computed tomographic (CT) or magnetic resonance (MR) imaging within 3 months prior to transplantation (21 patients with 44 tumors), imaging results were analyzed for sensitivity and specificity of residual or recurrent tumor by using histologic data as the reference standard. RESULTS: Thirty-five (74%) of 47 ablated tumors, including 29 (83%) of 35 tumors less than 3 cm, were found to be successfully treated on the basis of histologic findings after a mean interval of 7.5 months between RF ablation and transplantation. Nodules that were successfully treated had mean maximal diameter of 2.0 cm, and nodules that were unsuccessfully treated had mean maximal diameter of 3.1 cm (P=.014). Seven (47%) of 15 perivascular lesions were successfully treated whereas 28 (88%) of 32 nonperivascular lesions were successfully treated (P <.01). Imaging correlation showed 100% (33 of 33) specificity and 36% (four of 11) sensitivity of postablation CT and MR imaging for the depiction of residual or recurrent tumor. CONCLUSION: Histologic evidence directly validates RF ablation as an effective treatment of small (<3 cm) HCC.

Adult↗
PubMed2005

CD62 blockade with P-Selectin glycoprotein ligand-immunoglobulin fusion protein reduces ischemia-reperfusion injury after rat intestinal transplantation.

BACKGROUND: Intestinal transplantation (ITx) is severely limited by ischemia-reperfusion (I/R) injury. This study investigates I/R injury and ameliorates its consequences by using a recombinant protein targeted against selectins (recombinant P-selectin glycoprotein ligand-immunoglobulin [rPSGL-Ig]). METHODS: An isogeneic model of ITx was undertaken with control animals (no therapy) and treatment animals (rPSGL-Ig). Survival was assessed. Separate groups underwent an analysis examining tissue at multiple time points after I/R injury including histopathology; myeloperoxidase staining; immunostaining for CD3 and ED2; polymerase chain reaction analysis of interleukin (IL)-8/cytokine-inducible neutrophil chemoattractant, IL1beta, IL-6, interferon-gamma, IL-2, IL-4, and IL10; and western blots for hemoxygenase-1, BCL-2, and BCL-xl. Standard statistical analysis was undertaken. RESULTS: Treatment with rPSGL-Ig resulted in significantly improved survival after ITx. Analysis demonstrated diminished injury on histopathology and reduced tissue infiltration of neutrophils and lymphocytes. Significant differences in the cytokine profile after ITx were seen between the two groups including the production of inflammatory cytokines at 24 hr and the Th1 and Th2 cytokines at 2 and 4 hr. Last, treatment resulted in increased production of hemoxygenase, BCL-2, and BCL-xl. CONCLUSION: The results of this investigation of I/R injury after ITx revealed that rPSGL-Ig treatment led to marked improvement in outcome. The mechanism of action seems to involve the blockade of neutrophil and lymphocyte infiltration leading to a decreased inflammatory response possibly driven by Th2 cytokines. The results not only lend insight into the mechanisms behind I/R injury after ITx but also demonstrate a potential therapeutic modality to ameliorate its consequences.

Animals↗
PubMed2005

Percutaneous radiofrequency ablation of hepatocellular carcinoma as a bridge to liver transplantation.

Orthotopic liver transplantation (OLT) can be a definitive treatment for patients with hepatocellular carcinoma (HCC). Prolonged waiting times for cadaveric livers, however, may lead to dropout from the waiting list or worsened post-OLT prognosis as a result of interval tumor progression. Percutaneous radiofrequency ablation (RFA) is widely used for local control of small unresectable HCC, but its pretransplant role remains unclear. We studied the outcome of 52 consecutive patients accepted for OLT bearing 87 HCC nodules and treated with percutaneous RFA. On initial staging, the tumor burden exceeded the Milan criteria in 10 patients. Complete tumor coagulation was observed in 74 of 87 (85.1%) nodules based on postablation imaging. After a mean of 12.7 months (range: 0.3-43.5) on the waiting list, 3 of 52 patients (5.8%) had dropped out due to tumor progression. Forty-one patients had undergone transplantation, with 1- and 3-year post-OLT survival rates of 85% and 76%, respectively. No patient developed HCC recurrence. There were three major complications in 76 RFA procedures (hepatic arterial hemorrhage, small bowel perforation, and liver decompensation salvaged by OLT), without resultant death or dropout. In conclusion, percutaneous RFA is an effective bridge to OLT for patients with compensated liver function and safely accessible tumors. Tumor-related dropout rate and post-OLT outcome compared favorably with published controls of patients with early-stage disease. This can be attributed to the efficacy of RFA in producing local cure or curbing tumor progression during the waiting period.

Adult↗
PubMed2005

MELD fails to measure quality of life in liver transplant candidates.

Previous studies have demonstrated an association between Child Turcotte-Pugh (CTP) class and impaired quality of life. However, the relationship between the model for end-stage liver disease (MELD) score and quality of life (QOL) has not been well studied. In this study, quality of life questionnaires (Medical Outcomes Short Form 36 [SF-36] and the Chronic Liver Disease Questionnaire [CLDQ]) were administered to 150 adult patients awaiting liver transplantation. We also collected demographic data and laboratory results and recorded manifestations of hepatic decompensation. The study found that all domains of the SF-36 and CLDQ were significantly lower in our patient cohort than in normal controls (P < .001). There was a moderate negative correlation between CPT class and physical components of the SF-36 (r = -.30), while there was a weak negative correlation (r = -.10) between CPT class and the mental component. There was a negative moderate correlation between CPT class and overall CLDQ (r = -.39, P < .001) and a weak correlation (r = -.20) between MELD score and overall CLDQ score. Both encephalopathy (correlation coefficient = -.713, P = .004) and ascites (correlation coefficient = -.68, P = .006) were predictive of the QOL using CLDQ (adjusted R(2) = .1494 and f = 0.000). In conclusion, in liver transplant candidates, the severity of liver disease assessed by the MELD score was not predictive of QOL. The presence of ascites and/or encephalopathy was significantly associated with poor quality of life. CTP correlates better to QOL, probably because it contains ascites and encephalopathy.

Female↗
PubMed2005

Inflammatory responses in a new mouse model of prolonged hepatic cold ischemia followed by arterialized orthotopic liver transplantation.

The current models of liver ischemia/reperfusion injury (IRI) in mice are largely limited to a warm ischemic component. To investigate the mechanism of hepatic "cold" IRI, we developed and validated a new mouse model of prolonged cold preservation followed by syngeneic orthotopic liver transplantation (OLT). Two hundred and forty-three OLTs with or without rearterialization and preservation in University of Wisconsin solution at 4 degrees C were performed in Balb/c mice. The 14-day survivals in the nonarterialized OLT groups were 92% (11/12), 82% (9/11), and 8% (1/12) after 1-hour, 6-hour and 24-hour preservation, respectively. In contrast, hepatic artery reconstruction after 1-hour, 6-hour, and 24-hour preservation improved the outcome as evidenced by 2-week survival of 100% (12/12), 100% (10/10), and 33% (4/12), respectively, and diminished hepatocellular damage (serum alanine aminotransferase /histology). Moreover, 24-hour (but not 1-h) cold preservation of rearterialized OLTs increased hepatic CD4+ T-cell infiltration and proinflammatory cytokine (tumor necrosis factor-alpha, interleukin 2, interferon-gamma) production, as well as enhanced local apoptosis, and Toll-like receptor 4/caspase 3 expression. These cardinal features of hepatic IRI validate the model. In conclusion, we have developed and validated a new mouse model of IRI in which hepatic artery reconstruction was mandatory for long-term animal survival after prolonged (24-h) OLT preservation. With the availability of genetically manipulated mouse strains, this model should provide important insights into the mechanism of antigen-independent hepatic IRI and help design much needed refined therapeutic means to combat hepatic IRI in the clinics.

Adenosine↗
PubMed2005

AASLD/ILTS transplant course: is there an extended donor suitable for everyone?

1. The clinical success of liver transplantation coupled with the current era of organ shortage has caused many centers to expand their criteria for acceptable donors. 2. The definition of "Extended Criteria Donor" (ECD) is becoming better understood and quantified. 3. Recipient factors that portend poor outcome must be recognized and factored in as well. Grafts and recipients must be "matched" to manage and minimize the risk from ECDs. 4. Maintaining acceptable outcomes as ECD concepts evolve is paramount. 5. Absolute risk factors for poor graft function still exist and must be respected, but relative risk factors are now well identified, quantified, accepted, and managed as an alternative to high waiting list mortality.

Donor Selection↗
PubMed2005

Analysis of long-term outcomes of 3200 liver transplantations over two decades: a single-center experience.

OBJECTIVE: Few studies have evaluated long-term outcomes after orthotopic liver transplantation (OLT). This work analyzes the experience of nearly 2 decades by the same team in a single center. Outcomes of OLT and factors affecting survival were analyzed. METHODS: Retrospective analysis of 3200 consecutive OLTs that were performed at our institution, between February 1984 and December 31, 2001. RESULTS: Of 2662 recipients, 578 (21.7%) and 659 (24.7%) were pediatric and urgent patients, respectively. Overall 1-, 5-, 10-, and 15-year patient and graft survival estimates were 81%, 72%, 68%, 64% and 73%, 64%, 59%, 55%, respectively. Patient survival significantly improved in the second (1992-2001) versus the era I (1984-1991) of transplantation (P < 0.001). Similarly, graft survival was better in the era II of transplantation (P < 0.02). However, biliary and infectious complications increased in era II. When OLT indications were considered, best recipient survival was obtained in children with biliary atresia (82%, 79%, and 78% at 1, 5, and 10 years, respectively), while malignant disease in adult patients resulted in the worst outcomes of 68% and 43% at 1 and 5 years, post-OLT. Further, patients <18 years and nonurgent recipients exhibited superior survival when compared with recipients >18 years (P < 0.001) or urgent patients (P < 0.001). Of 13 donor and recipient variables, era of OLT, recipient age, urgent status, donor age, donor length of hospital stay, etiology of liver disease, retransplantation, warm and cold ischemia, but not graft type (whole, split, living-donor), significantly impacted patient survival. CONCLUSIONS: Long-term benefits of OLT are greatest in pediatric and nonurgent patients. Multiple factors involving the recipient, etiology of liver disease, donor characteristics, operative variables, and surgical experience influence long-term survival outcomes. By balancing and matching these factors with a given recipient, optimum results can be achieved.

Adolescent↗
PubMed2005

Mortality predictors in liver transplant recipients with recurrent hepatitis C cirrhosis.

BACKGROUND/AIM: Recipients of orthotopic liver transplant for hepatitis C (HCV) invariably develop recurrent disease. The risk factors for death and retransplantation following the development of cirrhosis from HCV are unclear. The aim of this study was to identify predictors of survival in liver transplant recipients who develop cirrhosis from recurrent HCV. METHODS: We reviewed records of patients who underwent liver transplantation for cirrhosis due to HCV between January 1990 and December 2001. Prognostic factors of patient survival following the development of recurrent cirrhosis were identified through multivariate analysis. RESULTS: During the study period, 511 patients underwent transplantation for HCV cirrhosis. Of these, 65 patients (13%) developed biopsy proven recurrent cirrhosis from HCV; 43 (8%) were relisted for transplantation, and 24 (5%) underwent retransplantation. The overall Kaplan-Meier patient survival rates after the histologic diagnosis of cirrhosis at 1 and 5 years were 66% and 30%, respectively. A multivariate Cox proportional hazards model showed patients with higher last (i.e. at follow-up or prior to retransplantation) International normalized ratio (INR) values (hazard ratios (HR)=2.02, 95% confidence interval 1.26, 3.24, P<0.01) to have an increased risk of death. CONCLUSION: Our results suggested survival was decreased after the diagnosis of cirrhosis from recurrent HCV. Higher INR was associated with an increased risk of death following the development of cirrhosis.

Adult↗
PubMed2005

Toll-like receptor and heme oxygenase-1 signaling in hepatic ischemia/reperfusion injury.

Ischemia/reperfusion injury (IRI) represents the major problem in clinical liver transplantation. We have shown that toll-like receptor 4 (TLR4) signaling is specifically required in initiating antigen-independent IRI leading to liver inflammation, whereas local induction of anti-oxidant heme oxygenase-1 (HO-1) is cytoprotective. This study analyzes in vivo interactions between HO-1 and sentinel TLR system in the pathophysiology of liver IRI. Using a 90-min lobar warm ischemia model, wild type (WT), TLR4 KO/mutant and TLR2 KO mice were first assessed for the severity of hepatocellular damage at 6 h postreperfusion. Unlike in WT or TLR2-deficient mice, disruption/absence of TLR4 pathway reduced IRI, as manifested by liver function (serum alanine aminotransferase levels), histology (Suzuki's scores), neutrophil infiltration (myeloperoxidase activity) and local/systemic TNF-alpha production (mRNA/protein levels). Moreover, defective TLR4 but not TLR2 signaling increased mRNA/protein HO-1 expression. In contrast, tin protoporphyrin-mediated HO-1 inhibition restored hepatic damage in otherwise IRI-resistant TLR4 mutant/KO mice. CoPP-induced HO-1 overexpression ameliorated hepatic damage in IRI-susceptible TLR2 KO mice, comparable with WT controls, and concomitantly diminished TLR4 levels. In conclusion, this study highlights the importance of cross talk between HO-1 and TLR system in the mechanism of hepatic IRI. Hepatic IRI represents a case for innate immunity in which HO-1 modulates proinflammatory responses that are triggered via TLR4 signaling, a putative HO-1 repressor.

Animals↗