PubMed Health⌕ Search

Biomedical subjects

Roberto J Firpi

Publications and source records attributed to Roberto J Firpi.

13 recordsLinked to original sources
PubMed2006

Cyclosporine suppresses hepatitis C virus in vitro and increases the chance of a sustained virological response after liver transplantation.

Cyclosporine is an immunosuppressive agent widely used in the management of liver transplant recipients. Cyclosporine has been shown to have antiviral activities against HIV, herpes simplex, and vaccinia viruses. The aim of this study was to determine the effect of Cyclosporine in viral clearance in the liver transplant recipients during therapy with combination of interferon and ribavirin, and to determine the anti-viral potential of Cyclosporine in vitro. Immunosuppression consisted of either Cyclosporine or Tacrolimus-based therapy. Both groups received therapy with interferon and ribavirin for 48 weeks when evidence of progressive histologic disease was determined. We found that subjects on Cyclosporine-based immunosuppression (n = 56) had a higher sustained virological response of 46% compared to 27% in the patients on Tacrolimus-based therapy (n = 59, P = 0.03). In vitro studies were performed to evaluate the antiviral effect of Cyclosporine in the replicon system. These studies showed that Cyclosporine inhibits hepatitis C viral replication in a dose-dependent manner. Combination of Cyclosporine with interferon showed additive effect, and its function is independent of interferon signaling pathways. In conclusion, Cyclosporine may offer an advantage to Tacrolimus in those patients undergoing interferon-based therapy and should be studied in a prospective randomized trial.

Adult↗
PubMed2006

Impact of implementation of the MELD scoring system on the prevalence and incidence of chronic renal disease following liver transplantation.

The implementation of the model for end-stage liver disease (MELD) score decreased mortality of those awaiting liver transplantation (LT); however, the impact of the MELD allocation system on the risk of chronic renal disease after LT remains unknown. We conducted a non-concurrent single-center cohort study of 174 patients undergoing LT at our center. We compared patients who underwent LT one year prior to MELD implementation (pre-MELD cohort) to those patients who underwent LT 1 year following MELD implementation (MELD cohort). All patients were followed for at least 2 years after LT. Stage 3 chronic renal disease (CRD-3) was defined by an estimated creatinine clearance (CL(Cr)) below 60 ml/min/1.73 m2, and stage 4 chronic renal disease (CRD-4) was defined by an estimated CL(Cr) below 30 mL/min/1.73 m2 according to the validated Modification of Diet and Renal Disease (MDRD) formula. Requirement of kidney transplantation and need for hemodialysis were also evaluated following LT. The pre-MELD cohort (n=97) and the MELD cohort (n=77) were comparable in baseline characteristics, prevalence of diabetes and hypertension, and immunosuppression. Mean calculated MELD score in the pre-MELD cohort was significantly lower than in the MELD cohort (16 vs. 19, P < 0.05). The estimated CL(Cr) at time of LT was lower in the MELD cohort compared with the pre-MELD cohort (75 vs. 95, P < 0.01). However, the incidence and prevalence of CRD-3 and CRD-4 at 6, 12, and 24 months after LT were comparable between the two cohorts. Need for kidney transplantation or hemodialysis after LT was comparable between the groups. In multivariate analysis, serum creatinine at LT was the only variable associated with the development of CRD-3 in the first 2 years after LT. In conclusion, the implementation of the MELD allocation system is not associated with increased mortality or occurrence of CRD-3 or CRD-4 in the first 2 years after LT.

Adolescent↗
PubMed2006

Viral hepatitis: manifestations and management strategy.

Viral hepatitis is the third most common cause of liver disease in allogeneic transplant recipients and causes significant morbidity and mortality. When treating patients with hematological malignancies, an emphasis should be placed on identification of patients at risk for viral hepatitis with appropriate screening. Initial screening serology should include anti-HCV, HBsAg, anti-HBs, and anti-HBc testing. When hepatitis B exposure has been documented, prophylaxis of viral reactivation for all HBsAg-positive patients with a nucleoside analogue should be implemented. HCV infection appears to have little short-term impact on survival after bone marrow transplantation, but is a risk factor for veno-occlusive disease (VOD) and graft-versus-host disease (GVHD). In the long-term survivor, HCV infection can lead to significant morbidity and mortality due to the development of cirrhosis, decompensation, and liver cancer. Since effective antiviral therapies are available for both hepatitis B and C, routine screening and selected intervention is recommended once reactivation and disease recurrence is documented. In this chapter we will highlight the mechanisms of virus reactivation, clinical manifestations, and management strategies to minimize acute and chronic morbidity in this population.

Disease Management↗
PubMed2005

Early hepatic stellate cell activation is associated with advanced fibrosis after liver transplantation in recipients with hepatitis C.

Recurrent hepatitis C after liver transplantation is a serious problem faced by liver transplant recipients. Activation of hepatic stellate cells is an early step in hepatic fibrogenesis. The aim of this study was to evaluate hepatic stellate cell activation, early after liver transplantation, as a predictor for the subsequent development of advanced fibrosis. Forty-six patients who underwent liver transplantation for hepatitis C and protocol liver biopsies were divided into rapid fibrosers (n = 21), defined as recipients who developed bridging fibrosis or cirrhosis within 2 years of liver transplantation, and slow fibrosers (n = 25). The protocol liver biopsy obtained 4 months after transplantation was stained and quantitated for hepatic stellate cell activation with antibody to alpha smooth muscle actin. Hepatic stellate cell activity was independently associated with rapid fibrosis (odds ratio: 1.6 [95% CI: 1.1,2.2], P = 0.013). The c-statistics for the receiver operating characteristic curve for stellate cell activity and fibrosis were 0.78 and 0.67, respectively, P = 0.36. The receiver operating characteristic curve for a model including stellate cell activity, histology activity index, and alanine aminotransferase. obtained at month 4 had the best c-statistic (0.88). In recipients with stage 0 or 1 fibrosis on the month 4 liver biopsy who subsequently developed advanced fibrosis, the c-statistic for the receiver operating characteristic curves was significantly better for stellate cell activity than for stage of fibrosis (0.77 and 0.51, respectively; P = 0.004). In conclusion, hepatic stellate cell activation early after liver transplantation complements traditional testing for identifying liver transplant recipients with hepatitis C at greatest risk for developing advanced fibrosis.

Adult↗
PubMed2005

Short recovery time after percutaneous liver biopsy: should we change our current practices?

BACKGROUND & AIMS: Percutaneous liver biopsy is the gold standard in the diagnosis and staging of a wide variety of hepatic disorders. Complications, post-procedure monitoring, and recovery time have limited the ability for liver biopsies to be performed in a busy gastroenterology community practice. The aim of this study was to determine whether ambulatory patients requiring percutaneous liver biopsy can be safely discharged after a short recovery time period. METHODS: All ambulatory patients undergoing a percutaneous liver biopsy at the University of Florida between February 1995 and June 2004 were evaluated in this study. A 15-gauge Jamshidi needle was used after percussion (before February 2002) or ultrasound guidance (starting February 2002). Major complications were defined as those events that required either immediate or delayed hospitalization or resulted in death within 2 weeks after the liver biopsy. RESULTS: Three thousand two hundred fourteen outpatient liver biopsies were performed at our institution from March 1995 to June 2004. During this time, our recovery time was gradually decreased from 6 hours before 1997 to 1 hour in 2002. The majority of the complications occurred within 1 hour of the observation period or within 24 hours after discharge. The major complication rate was < or =1.7%, regardless of the observation period. CONCLUSIONS: A shorter observation time after ambulatory percutaneous liver biopsy is safe and might facilitate the physician's ability to optimally utilize procedural space and ancillary staff in a busy ambulatory care unit.

Biopsy, Needle↗
PubMed2004

An immunomodulatory role for CD4(+)CD25(+) regulatory T lymphocytes in hepatitis C virus infection.

The CD4(+)CD25(+) regulatory T lymphocytes have been implicated in suppressing T cell immune responses. Our aim was to characterize the frequency, phenotype, function, and specificity of CD4(+)CD25(+) T cells in hepatitis C virus (HCV) infection. Peripheral CD4(+)CD25(+) cells from recovered (n = 15), chronic infected (n = 30), and normal control (n = 15) subjects were analyzed ex vivo for quantitation, phenotype, and effect on HCV-specific interferon gamma production and proliferation. CD4(+)CD25(+) specificity was determined by intracellular cytokine staining for interleukin 10 (IL-10). A higher proportion of CD4(+)CD25(+) were found in chronic infection (mean, 3.02%) when compared with recovered (1.64%, P = .001) and normal controls (2.27%, P = .02). CD4(+)CD25(+) cells display CD45RO(high), CD45RA(low), CD28(high), CD62L(high), and CD95(high) phenotype. HCV-specific interferon gamma activity was enhanced in peripheral blood mononuclear cells depleted of CD4(+)CD25(+) and suppressed in peripheral blood mononuclear cells enriched with CD4(+)CD25(+). Depletion of CD4(+)CD25(+) cells also enhanced HCV-specific CD4(+) and CD8(+) T cell proliferation. Cytokine analysis suggested CD4(+)CD25(+) cells secrete transforming growth factor beta (TGF-beta(1)) and IL-10. The inhibitory role for TGF-beta(1) was confirmed by anti-TGF-beta(1). Transwell studies showed CD4(+)CD25(+) mediated suppression to be dose dependent and requiring cell contact. CD4(+)CD25(+) cells showed HCV-specificity through IL-10 production, with a frequency ranging from 1.9% to 5.3%. A positive correlation was detected between CD4(+)CD25(+) T cell frequency and HCV RNA titer, whereas an inverse relation was found with liver inflammatory activity. In conclusion, CD4(+)CD25(+) T lymphocytes constitute a highly differentiated population and appear to play a role in viral persistence by suppressing HCV-specific T cell responses in a cell-cell contact manner.

Antibodies↗
PubMed2004

Sustained viral response to interferon and ribavirin in liver transplant recipients with recurrent hepatitis C.

Recurrent hepatitis C infection is an important cause of progressive fibrosis, cirrhosis, and graft loss following orthotopic liver transplantation. Treatment for posttransplant recurrence of hepatitis C with interferon-based therapy is difficult but results in loss of detectable virus in up to 30% of patients. However, the durability of viral clearance and the associated histologic response in this setting is unknown. The aim of this study was to determine whether viral loss in response to antiviral therapy is durable and associated with improvement in liver histology. All liver transplant recipients who received interferon-based treatment for recurrent hepatitis C virus (HCV) at the University of Florida from 1991 to 2002 were included in this study. Patients who lost detectable HCV after treatment with interferon alone or in combination with ribavirin were followed to assess the durability of viral response and its impact on liver histology. One hundred nineteen transplant recipients were treated with interferon or combination therapy. Twenty-nine (20 men, 9 women; mean age, 54 yrs [range, 42-74 yrs]) lost detectable HCV RNA and remained virus negative for at least 6 months after discontinuing therapy (sustained viral response[SVR]). The mean follow-up after discontinuing therapy was 24.7 months (range, 6-70 mos). Our study cohort included one patient with SVR following interferon monotherapy and 28 patients with SVR following combination therapy with interferon plus ribavirin. All patients remained HCV RNA negative (assessed by polymerase chain reaction or branched-DNA assay) during follow-up of up to 5 years. Liver histology assessed 2 years after treatment showed less inflammation compared with before treatment in 50% and showed no change in 38%. By 3 to 5 years post-treatment (n = 15 recipients), inflammation was reduced in 60% and remained unchanged in 33%. Fibrosis stage at 2 years improved by > or = 1 stage in 27 %, remained unchanged in 38 %, and worsened in 35% despite viral clearance. At 3 to 5 years, the fibrosis stage had improved in 67%, remained unchanged in 13%, and worsened in 20%. Both grade of inflammation and fibrosis stage improved by 3 to 5 years posttreatment compared with baseline histology (p < 0.05). In conclusion, loss of HCV after treatment of recurrent chronic hepatitis C with interferon and ribavirin is durable, and the durability of the SVR is associated with improvement in hepatic inflammation and regression of fibrosis.

Adult↗
PubMed2004

One-year protocol liver biopsy can stratify fibrosis progression in liver transplant recipients with recurrent hepatitis C infection.

Determinants of progression to cirrhosis in hepatitis C virus (HCV) infection have been well described in the immunocompetent population but remain poorly defined in liver transplant (LT) recipients. This cohort study determines the factors contributing to the development of fibrosis and its rate of progression in the allograft. Predictive factors analyzed include: demographics, host and donor factors, surgery-related variables (cold and warm ischemia time), rejection episodes, cytomegalovirus infection (CMV), and immunosuppression. Over 12 years, 842 adult LTs were performed at our institution; 358 for the indication of HCV. A total of 264 patients underwent protocol liver biopsies at month 4 and yearly after LT. Using the modified Knodell system of Ishak for staging fibrosis, the median fibrosis progression rate was .8 units/year (P < .001). Rapid fibrosis progression (> .8 units/year) was best identified by liver histology performed at 1 year. Donor age > 55 years was associated with rapid fibrosis progression and development of cirrhosis (P < .001). In contrast, donor age < 35 years was associated with slower progression of fibrosis (P = .003). Risk factors for graft loss due to recurrent HCV included recipient age > 35 years (P = .01), donor age > 55 years (P = .005), and use of female donor allografts (P = .03). In conclusion, fibrosis progression in HCV-infected LT recipients occurs at a rate of .8 units/year. Increased donor age has a major impact on disease progression, graft failure, and patient survival. A liver biopsy performed at 1 year posttransplant can help identify those patients more likely to develop progressive disease and may allow better targeting of antiviral therapy.

Adult↗
PubMed2003

Lack of antiviral effect of a short course of mycophenolate mofetil in patients with chronic hepatitis C virus infection.

Mycophenolate mofetil (MMF) is an immunosuppressive agent that is widely used in the management of liver transplant recipients. MMF inhibits the inosine monophosphate dehydrogenase that has been shown to have in vitro antiviral properties against flaviviruses, suggesting the possibility that it might also inhibit the hepatitis C virus (HCV). The goal of this short-term dose escalation study was to assess the antiviral effects of MMF on HCV replication. Patients with chronic hepatitis C who had not undergone liver transplantation were randomized to 8 weeks of treatment with one of four mycophenolate dose regimens (1000 mg orally twice daily, 500 mg orally twice daily, 250 mg orally twice daily, or a matched oral placebo twice daily). All groups were double-blinded. Quantitative HCV RNA levels and serum alanine aminotransferase were assessed at baseline, at weeks 2, 4, and 8 of dosing, and at weeks 4 and 8 of follow-up. Thirty patients met inclusion criteria, enrolled, and were randomized. HCV RNA levels did not change significantly during treatment. Specifically, no subject became virus negative or had a one-log decrease in virus level. Serum aminotransferase level did not normalize in any subject. The most common side effects were headache, nausea, and diarrhea. Mycophenolate alone does not appear to have a significant antiviral or biochemical effect in patients with chronic hepatitis C.

Adult↗
PubMed2002

Combination of interferon alfa-2b and ribavirin in liver transplant recipients with histological recurrent hepatitis C.

Recurrent hepatitis C virus (HCV) infection is an important cause of fibrosis and cirrhosis after liver transplantation (LT), with histological recurrence developing in at least 50% of patients within the first year. The aim of this study is to assess the safety and efficacy of interferon alfa-2b plus ribavirin in treating histological recurrent HCV after LT. Since 1998, patients with HCV with significant histological recurrence (fibrosis >/= 3 and/or histological activity index >/= 5) or progressive cholestatic disease after LT were treated with interferon alfa-2b (3 million units subcutaneously three times weekly) plus ribavirin (800 to 1,000 mg/d) for 12 months. Immunosuppression was tapered to cyclosporine/FK506 monotherapy. HCV RNA was assessed at entry, week 24, end of treatment, and 6 months after therapy. The primary end point was loss of HCV RNA 6 months after therapy, whereas the secondary end point was histological response. Fifty-four patients met criteria for treatment and have completed follow-up. Patients were mainly men (71% men; mean age, 51 +/- 5 years) with genotype 1 infection (88%) and high viral load (mean HCV RNA, 38 +/- 9 mEq/mL). Dose modification was required in 72% of patients because of cytopenia or side effects. Intent-to-treat analysis showed that serum HCV RNA was undetectable in 19 patients (35%) week 24, 21 patients (38%) week 48, and 16 patients (30%) at the 6-month follow-up. Paired liver biopsy results (before and within 6 months after treatment) were available for 35 patients. Patients who achieved viral eradication had no significant progression of fibrosis after 1 year of therapy. In summary, combination therapy is a reasonable antiviral option for recurrent HCV infection for established post-LT hepatitis and appears to prevent histological progression of disease if viral eradication is successful.

Adult↗