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Robert L Carithers

Publications and source records attributed to Robert L Carithers.

17 recordsLinked to original sources
PubMed2006

Identification of a specific gene expression pattern associated with HCV-induced pathogenesis in HCV- and HCV/HIV-infected individuals.

Gene expression profiling was performed on liver biopsies from 28 patients (12 HCV and 16 HCV/HIV infected) in an attempt to understand the mechanisms of HCV liver disease in the presence and absence of HIV coinfection. The data were compared with clinical observations and a gene expression database obtained for transplant HCV-infected samples. This is the first report of functional genomics being used to compare intrahepatic gene expression profiles of HCV- and HCV/HIV-infected individuals. Significantly, the intrahepatic global gene expression profiles do not differ between HCV- and HCV/HIV-infected individuals. However, a subset of patients was identified who share a specific pattern of gene expression, termed the enhanced gene expression (EGE) pattern. Specifically, the EGE (+) patients show a dramatic decreased expression of multiple genes associated with the FAS-apoptosis pathway and increased expression of lymphocyte adhesion molecules and lymphocyte-specific genes. The EGE (+) patients also have partially impaired Type I and II IFN-mediated antiviral responses, including a lack of induction of the anti-fibrogenic cytokine IFN-gamma. Importantly, the pattern of gene expression observed in EGE (+) patients has similarities to patients who developed fibrosis within 1 year of receiving a liver transplant.

Female↗
PubMed2006

Gene expression patterns that correlate with hepatitis C and early progression to fibrosis in liver transplant recipients.

BACKGROUND & AIMS: Liver transplant recipients infected with hepatitis C virus (HCV) develop recurrent hepatitis soon after transplantation and, in some cases, progress to fibrosis within the first 2 years. Our goals were to identify molecular processes influencing the liver disease progression and to find potential gene markers of early fibrosis. METHODS: We performed gene expression profiling on serial liver biopsy specimens obtained from 13 (11 infected and 2 uninfected) transplant recipients within the first year after transplantation at 0, 3, 6, and 12 months. The data were compared with clinical observations and with a gene expression database obtained for 55 nontransplant HCV-infected and uninfected liver samples. RESULTS: We identified several specific gene expression patterns. The first pattern was unique for the transplant recipients regardless of their infection status. The corresponding genes encoded stress response proteins and blood proteins involved in coagulation that were differentially expressed in response to posttransplantation graft recovery. The second pattern was specific to HCV-infected samples and included up-regulation of genes encoding components of the interferon-mediated antiviral response and immune system (antigen presentation, cytotoxic response). This up-regulation pattern was absent or suppressed in the patients who developed early fibrosis, indicating that the disease progression might result from an impaired liver response to infection. Finally, we identified gene expression patterns that were specific for 12-month biopsy specimens in all 4 HCV-infected patients who developed early fibrosis. CONCLUSIONS: The identified gene expression patterns may prove useful for diagnostic and prognostic applications in HCV-infected patients, including predicting early progression to fibrosis.

Adult↗
PubMed2006

Productive replication of hepatitis C virus in perihepatic lymph nodes in vivo: implications of HCV lymphotropism.

BACKGROUND & AIMS: The pathogenesis of chronic hepatitis C is poorly understood. This study examines the ability of hepatitis C virus (HCV) to infect, replicate in, and produce progeny virus from perihepatic lymph nodes in vivo. METHODS: Lymph node (LN) biopsy specimens were taken from 20 patients with HCV genotype 1 infection and end-stage liver disease and 20 noninfected negative controls. Sections were probed with HCV RNA strand-specific riboprobes and antibodies specific for HCV core and nonstructural region 3 antigens plus B-cell (CD20) and T-cell (CD2) antigens. In a selected case, HCV quasispecies in serum, peripheral blood mononuclear cells, liver, and perihepatic lymph nodes were analyzed by clonal frequency analysis and sequencing. RESULTS: HCV infection was confirmed in 17 of 20 (85%) of lymph node specimens by in situ hybridization, and HCV replication was confirmed in 50% of cases by detection of HCV replicative intermediate RNA. HCV core and nonstructural 3 antigens were detected in lymph nodes by immunocytochemistry. Infected cell phenotypes were primarily CD20 B cells, although other cell types were positive for HCV replication markers. Quasispecies analysis in one case indicated that 68% of variants circulating in serum were also present in lymphoid tissues, and only 40% of serum variants were identified in liver, documenting a major contribution of lymphoid replication to HCV viremia. CONCLUSIONS: HCV lymphotropism provides new insights into the complex pathobiology of chronic hepatitis C in humans. We demonstrate for the first time a major contribution of extrahepatic HCV replication to circulating virus in serum (viremia).

Antigens, CD20↗
PubMed2005

Using root cause analysis to improve survival in a liver transplant program.

BACKGROUND: With the advent of programs such as the American College of Surgeons-National Surgical Quality Improvement Program, surgical services will be compared with their peers across the United States. At times, many programs will experience lower-than-expected outcomes. During July 1, 1998, to June 30, 2000 our 1-year graft (76.86%, P = 0.23) and patient (80.61%, P = 0.016) survivals after liver transplantation were lower than our expected rates (graft 81.89% and patient 88.3%), according to the U.S. Scientific Registry of Transplant Recipients (SRTR). METHODS: We used aggregate root cause analysis to determine underlying reasons for our patient deaths. Two of our surgeons performed a systematic review of all our center's liver transplant patient deaths from January 1, 1995, to December 31, 2000. Each phase of the transplant process was reviewed. RESULTS: Of 355 patients receiving their first transplant, there were 90 deaths, with 188 root causes identified. The apportionment according to phase of the transplant process was patient selection, 50%; transplant procedure, 17%; donor selection, 15%; post-transplant care, 8%, and psychosocial issues, 10%. Risk reduction action plans were developed, and several important changes made in our care protocol. In April 2004, SRTR data revealed that for patients transplanted between January 1, 2001 and June 30, 2003, our 1-year liver graft survival of 90.73% (P = 0.018) was significantly higher than the national expected rate of 84.48%. Our 1-year patient survival rate of 92.66% (P = 0.285) was higher than the expected rate of 89.29%. CONCLUSIONS: Lower-than-expected outcomes can provide an impetus for improving patient care and raising the quality of a surgical service. Aggregate root cause analysis of adverse events is a valuable method for program improvement.

Cause of Death↗
PubMed2005

Methotrexate (MTX) plus ursodeoxycholic acid (UDCA) in the treatment of primary biliary cirrhosis.

This placebo-controlled, randomized, multicenter trial compared the effects of MTX plus UDCA to UDCA alone on the course of primary biliary cirrhosis (PBC). Two hundred and sixty five AMA positive patients without ascites, variceal bleeding, or encephalopathy; a serum bilirubin less than 3 mg/dL; serum albumin 3 g/dL or greater, who had taken UDCA 15 mg/kg daily for at least 6 months, were stratified by Ludwig's histological staging and then randomized to MTX 15 mg/m2 body surface area (maximum dose 20 mg) once a week while continuing on UDCA. The median time from randomization to closure of the study was 7.6 years (range: 4.6-8.8 years). Treatment failure was defined as death without liver transplantation; transplantation; variceal bleeding; development of ascites, encephalopathy, or varices; a doubling of serum bilirubin to 2.5 mg/dL or greater; a fall in serum albumin to 2.5 g/dL or less; histological progression by at least two stages or to cirrhosis. Patients were continued on treatment despite failure of treatment, unless transplantation ensued, drug toxicity necessitated withdrawal, or the patient developed a cancer. There were no significant differences in these parameters nor to the time of development of treatment failures observed for patients taking UDCA plus MTX, or UDCA plus placebo. The trial was conducted with a stopping rule, and was stopped early by the National Institutes of Health at the advice of our Data Safety Monitoring Board for reasons of futility. In conclusion, methotrexate when added to UDCA for a median period of 7.6 years had no effect on the course of PBC treated with UDCA alone.

Adult↗
PubMed2005

Liver transplantation for erythropoietic protoporphyria liver disease.

In erythropoietic protoporphyria (EPP), there is excessive production of protoporphyrin, primarily in the bone marrow, resulting in increased biliary excretion of this heme precursor. Some patients will develop progressive liver disease that may ultimately require liver transplantation. However, excessive production of protoporphyrin by the bone marrow continues after transplantation, which may cause recurrent disease in the allograft. This study was performed to define post-transplant survival, the risk of recurrent disease, and specific management issues in patients transplanted for EPP liver disease. The patients studied consisted of twelve males and eight females, with an average age of 31 (range, 13-56) years at the time of transplantation. The estimated maximum MELD score prior to transplant was 21 (range, 15-29). Unique complications in the perioperative period were light induced tissue damage in four patients and neuropathy in six, requiring prolonged mechanical ventilation in four. Patient and graft survival rates were 85% at 1 year, 69% at 5 years, and 47% at 10 years. Recurrent EPP liver disease occurred in 11 of 17 patients (65%) who survived more than 2 months. Three patients were retransplanted at 1.8, 12.6, and 14.5 years after the initial transplant for recurrent EPP liver disease. In conclusion, the 5-year patient survival rate in patients transplanted for EPP liver disease is good, but the recurrence of EPP liver disease appears to diminish long term graft and patient survival.

Adolescent↗
PubMed2005

Is central obesity associated with cirrhosis-related death or hospitalization? A population-based, cohort study.

BACKGROUND & AIMS: We aimed to determine the interaction between body fat distribution (central versus peripheral) and increased body mass index (BMI) with regards to the risk of cirrhosis-related death or hospitalization. METHODS: Participants included 11,434 persons aged 25-74 years without evidence of cirrhosis at entry into the study or during the first 5 years of follow-up who were subsequently followed for a mean of 12.9 years as part of the first National Health and Nutrition Examination Survey. Participants were categorized into "normal-weight" (BMI < 25 kg/m 2 , N = 5750), "overweight" (BMI 25 to < 30 kg/m 2 , N = 3770), and "obese" (BMI > or = 30 kg/m 2 , N = 1914). The subscapular to triceps skinfold thickness ratio (SFR) was used to categorize body fat distribution into central (SFR > 1, N = 5211) and peripheral (SFR < or = 1, N = 6223). RESULTS: Cirrhosis resulted in death or hospitalization of 88 participants during 149,888 person-years of follow-up (59/100,000 person-years). Among persons with a central body fat distribution, cirrhosis-related deaths or hospitalizations were more common in obese persons (115/100,000 person-years, adjusted hazard ratio 2.2, 95% confidence interval [CI] 1.1-4.6) and in overweight persons (94/100,000 person-years, adjusted hazard ratio 1.5, 95% CI 0.8-3.0) compared to normal-weight persons (59/100,000 person-years). However, among persons with a peripheral fat distribution, there was no association between obesity (adjusted hazard ratio 0.7, 95% CI 0.3-1.6) or overweight (adjusted hazard ratio 0.8, 95% CI 0.2-2.8) and cirrhosis-related death or hospitalization. CONCLUSIONS: The risk of cirrhosis-related death or hospitalization appears to be increased in the presence of cirrhosis, but only among persons with a central fat distribution. The excess risk associated with central obesity might be related to insulin resistance and hepatic steatosis.

Adult↗
PubMed2005

Proteome analysis of liver cells expressing a full-length hepatitis C virus (HCV) replicon and biopsy specimens of posttransplantation liver from HCV-infected patients.

The development of a reproducible model system for the study of hepatitis C virus (HCV) infection has the potential to significantly enhance the study of virus-host interactions and provide future direction for modeling the pathogenesis of HCV. While there are studies describing global gene expression changes associated with HCV infection, changes in the proteome have not been characterized. We report the first large-scale proteome analysis of the highly permissive Huh-7.5 cell line containing a full-length HCV replicon. We detected >4,200 proteins in this cell line, including HCV replicon proteins, using multidimensional liquid chromatographic (LC) separations coupled to mass spectrometry. Consistent with the literature, a comparison of HCV replicon-positive and -negative Huh-7.5 cells identified expression changes of proteins involved in lipid metabolism. We extended these analyses to liver biopsy material from HCV-infected patients where a total of >1,500 proteins were detected from only 2 mug of liver biopsy protein digest using the Huh-7.5 protein database and the accurate mass and time tag strategy. These findings demonstrate the utility of multidimensional proteome analysis of the HCV replicon model system for assisting in the determination of proteins/pathways affected by HCV infection. Our ability to extend these analyses to the highly complex proteome of small liver biopsies with limiting protein yields offers the unique opportunity to begin evaluating the clinical significance of protein expression changes associated with HCV infection.

Amino Acid Sequence↗
PubMed2004

Prolonged follow-up of patients in the U.S. multicenter trial of ursodeoxycholic acid for primary biliary cirrhosis.

OBJECTIVE: Randomized, double-blind, placebo-controlled trials of ursodeoxycholic acid (UDCA) in patients with primary biliary cirrhosis (PBC) have not demonstrated improvement in survival during the placebo-controlled phases of these trials. Analyses purporting to demonstrate a survival advantage of UDCA are largely dependent on data obtained after the placebo phases were terminated, and placebo-treated patients were offered open-label UDCA. After completion of our 2-yr placebo-controlled trial of UDCA in which we observed no survival benefit for UDCA, we provided the patients with open-label UDCA to see if delay in providing UDCA for 2 yr had any effect on subsequent liver transplantation or death without liver transplantation. METHODS: In our previously reported 2-yr placebo-controlled trial, 151 patients with PBC were randomized to receive either UDCA (n = 77) or placebo (n = 74). The number of patients who progressed to liver transplantation or death without transplantation were similar in both the groups, 12 (16%) in the UDCA-treated and 11 (15%) in placebo-treated patients. All the patients were then offered open-label UDCA, with 61 original UDCA and 56 original placebo-treated patients now taking UDCA in an extended open-label phase of the trial. RESULTS: No significant differences were observed in the number of patients who underwent liver transplantation or died without liver transplantation in the open-label phase of the trial. Moreover, no difference in the time to these endpoints was seen over the period of observation of as long as 6 yr from the time of initial randomization. CONCLUSIONS: Results of open-label extensions of previous conducted placebo-controlled trials of UDCA in PBC leave uncertain whether UDCA impacts significantly on liver transplantation and death without liver transplantation in patients with PBC.

Cholagogues and Choleretics↗
PubMed2003

Hepatitis C virus and liver disease: global transcriptional profiling and identification of potential markers.

Microarray analysis of RNA from hepatitis C virus (HCV)-infected cirrhotic livers was performed to identify a gene expression signature of liver disease. The expression levels of approximately 13600 genes were analyzed using surgical material and core biopsy specimens from HCV-infected cirrhotic liver explants in comparison with reference samples of normal nondiseased liver. In addition, normal liver samples were compared with each other to determine normal physiologic variation in gene expression. A set of genes, including some associated with stress, acute-phase immune response, and hepatic stellate cell activation, had variable expression levels in normal livers. These genes were subtracted from the sets of genes differentially expressed in cirrhotic livers. To exclude cancer-related genes from our marker sets, we subtracted genes that also were expressed differentially in hepatocellular carcinomas. The resultant HCV- and liver disease-associated gene set provided a molecular portrait of several processes occurring in the HCV-infected liver. It included (1). genes expressed in activated lymphocytes infiltrating the cirrhotic liver, and activated liver macrophages; (2). genes involved in remodeling of extracellular matrix-cell and cell-cell interactions associated with cytoskeleton rearrangements; (3). genes related to the anti-apoptotic pathway of Bcl-2 signaling; and (4). genes involved with the interferon response and virus-host interactions. In conclusion, our microarray analysis identified several potential gene markers of HCV-associated liver disease and contributed to our rapidly expanding database of experiments describing HCV pathogenesis.

Apoptosis↗
PubMed2003

Dynamics of hepatitis C virus replication in human liver.

Hepatitis C virus (HCV) replication at the cellular level is not fully understood. This study describes an optimized system for quantifying replication of HCV in hepatocytes and in liver tissues. A digital image analysis method was developed to quantify signal intensities of HCV genomic and replicative-intermediate RNAs in infected human liver tissues and to examine their spatial distribution. The average number of viral genomes per productively infected hepatocyte ranged from 7 to 64 RNA molecules. The maximal concentrations of genomic and replicative-intermediate RNAs at the single cell level were 74 and 34 molecules per hepatocyte, respectively. A gradient dispersion of genomes was observed around virus-producing cells, suggesting infection of neighboring hepatocytes as one mechanism of viral spread in the liver. There was no significant difference in total hepatic load of HCV genomes between the post- and nontransplant patients, whereas serum titers in the former group were much higher that that in the latter group. HCV replication varied among infected hepatocytes, occurred in a subset of cells, and proceeded at a low level, confirming one mechanism by which individual hepatocytes are cumulatively able to generate steady state concentrations of millions of HCV genomes per milliliter of blood. Lower viral clearance rates in circulating blood may explain the phenomenon of increased serum titers of viral RNA in posttransplant immunosuppressed patients.

Genome, Viral↗
PubMed2003

Transiently altered acetaminophen metabolism after liver transplantation.

BACKGROUND AND OBJECTIVES: Acetaminophen (INN, paracetamol) is metabolized to N-acetyl-p-benzoquinone imine (NAPQI), a hepatotoxic metabolite, predominantly by cytochrome P450 (CYP) 2E1. Alterations in drug metabolism occur after organ transplantation. This study was designed to characterize acetaminophen disposition during the first 6 months after liver transplantation. METHODS: Thirteen liver transplant patients received an oral dose of acetaminophen (500 mg) on days 2, 10, 90, and 180 after transplantation. Serial blood samples were collected for 8 hours, and urine was collected for 24 hours. Liver biopsy specimens were obtained from the donor liver during transplantation (day 0) and on days 10, 90, and 180 after transplantation. RESULTS: There were significant time-dependent changes in acetaminophen metabolism after liver transplantation. When day 2 and day 10 were compared with day 180, the respective mean urinary recovery was 137% and 81% higher for thioether conjugates derived from NAPQI (P =.0002 and P =.01, respectively); 31% and 22% lower for acetaminophen sulfate (P =.0006 and P =.008, respectively); and 22% and 27% lower for acetaminophen glucuronide (P =.05 and P =.004, respectively). Metabolite formation clearances changed in concordance with the fractional urinary recovery. It was surprising that hepatic CYP2E1 content on day 10 after transplantation was only 20% higher, on average, than that found on day 180 (not significant). In contrast, hepatic CYP3A4 content was 984% higher, on average, when tissue from days 10 and 180 was compared after transplantation (P =.007). CONCLUSIONS: Increased recovery of acetaminophen thioether conjugates during the first 10 days after liver transplantation was a result of impaired glucuronidation and sulfation and enhanced NAPQI formation.

Acetaminophen↗
PubMed2003

Primary biliary cirrhosis: specific treatment.

No single agent or combination of agents has been shown to unequivocally delay the need for liver transplantation or reduce mortality in patients with PBC. Given this uncertainty, what, if any, specific therapy should be recommended? The agents with the strongest scientific proof of efficacy in well-designed clinical trials are ursodiol, azathioprine, and cyclosporine. Ursodiol is clearly the least toxic of these three. Other agents, such as methotrexate, have shown impressive results in anecdotal studies but have never been adequately tested in randomized clinical trials. Thus, based on the current evidence, imperfect as it is, ursodiol appears to be the safest and potentiaily the most effective specific therapy for patients with PBC. Azathioprine and methotrexate may be the best alternatives for patients who cannot tolerate or do not respond to ursodiol therapy, primarily because their safety has been established in large and lengthy clinical trials. Cylosporine could be considered in patients who fail other treatments (Table 3). We can hope that a safe, highly-effective treatment for patients with PBC will ultimately be discovered. Trials to unequivocally demonstrate the efficacy of new agents will have to be extremely well designed, however, and will require large numbers of patients followed for an extended period of time.

Clinical Trials as Topic↗
PubMed2003

Hepatitis C virus-specific cytolytic T cell responses after antiviral therapy.

Antigen-specific T cells are likely to provide a critical defense against hepatitis C virus (HCV) infection. However, their detection in blood is uncommon except in persons who undergo spontaneous recovery after acute HCV infection. We postulated that virological responses after antiviral interferon-alpha therapy may be associated with enhanced cytolytic T cell immunity. Peripheral blood memory CTL responses were quantified using short term limiting dilution culture, with cytolytic function detected by standard chromium release assay. In this cross-sectional study, 5 of 11 interferon-alpha or interferon-alpha plus ribavirin-treated subjects exhibited cytolytic T cell responses after therapy completion; 4 of these 5 subjects were HCV RNA negative at the time of assay. In contrast, only 1 of 9 untreated chronically viremic subjects had detectable HCV-specific cytolytic T cell responses. Although the requisite factors necessary to achieve sustained virologic response after therapy remain largely undefined, the findings presented here suggest that antiviral therapy-induced virological clearance may be associated with the induction, expansion, and/or recirculation of HCV antigen-specific cytolytic T cells, and may play a role in the maintenance of a nonviremic state.

Adult↗
PubMed2003

A multicenter study of recombinant human interleukin 12 for the treatment of chronic hepatitis C virus infection in patients nonresponsive to previous therapy.

Recombinant human interleukin 12 (IL-12) is an immunomodulatory cytokine that is active against several viruses. Treatment options in patients with chronic hepatitis C with nonresponse to interferon (IFN)-based therapy are limited. Prior dose-ranging studies have indicated drug tolerability and transient suppression of hepatitis C virus (HCV) RNA by IL-12. The aim of this study was to determine the safety and efficacy of prolonged IL-12 therapy in patients who have failed treatment with IFN-alpha +/- ribavirin. A total of 225 patients at 21 U.S. sites who had a history of nonresponse to IFN-alpha or combination IFN-alpha plus ribavirin for treatment of HCV were randomized to 500 ng/kg IL-12 or placebo subcutaneously twice weekly for 12 weeks. The groups were then unblinded; patients receiving IL-12 continued for another 36 weeks, and the placebo group received 48 weeks of treatment with IL-12 in an open-label fashion. HCV RNA, serum alanine aminotransferase (ALT) level, and a repeat liver biopsy were assessed at 24 weeks following therapy. Approximately 1% (2 of 160) of nonresponsive patients enrolled for treatment had a sustained virologic response to IL-12 therapy, but 3% (7 of 225) developed severe adverse events probably related to treatment, resulting in early termination of the trial. Common adverse effects reported by most patients included chills, fever, fatigue, headache, and arthralgia. At termination of the study, 160 patients had received at least 8 weeks of treatment with IL-12. Paired liver biopsy specimens were available for evaluation in 54 patients, but there were no significant changes in Knodell fibrosis or histologic activity index (HAI) scores. In conclusion, IL-12 as monotherapy at the doses used in this trial for chronic hepatitis C has low efficacy, was poorly tolerated, and is unlikely to provide an alternative to conventional IFN-based therapy.

Adjuvants, Immunologic↗
PubMed2002

Corticosteroids improve short-term survival in patients with severe alcoholic hepatitis (AH): individual data analysis of the last three randomized placebo controlled double blind trials of corticosteroids in severe AH.

BACKGROUND/AIMS: Controversy surrounding the efficacy of corticosteroids in severe alcoholic hepatitis (AH) persists. THE AIMS OF OUR STUDY WERE: (a) to analyze individual data of patients with severe AH discriminant function (DF)> or =32 from the last three randomized controlled trials; and (b) to identify the independent prognostic factors associated with short-term survival. METHODS: Individual data were collected from the three principal investigators. Survival analysis was performed at 28 days using the Kaplan-Meier method and log-rank test. The independent prognostic values were assessed by the proportional hazards regression model. RESULTS: About 102 placebo and 113 corticosteroid patients with DF > or =32 were analyzed. At 28 days, corticosteroid patients had significantly higher survival: 84.6+/-3.4% vs. 65.1+/-4.8%, P=0.001. In univariate analysis, corticosteroid treatment, age, DF, albumin, creatinine and encephalopathy were prognostic factors. In multivariate analysis, age (P=0.0001), serum creatinine (P<0.002) and corticosteroid treatment (P=0.002) were independent prognostic variables. A more dramatic decrease of median serum bilirubin values (micromol/l) was observed at 7 and 14 days in corticosteroid patients (P<0.05) : -76.5 vs. -35 and -105 vs. -45. CONCLUSIONS: Corticosteroids improved short-term survival of patients with severe AH. Age and serum creatinine are independent prognostic factors. Corticosteroids are recommended for patients with severe AH.

Adrenal Cortex Hormones↗