Biomedical subjects

José Mir

Publications and source records attributed to José Mir.

7 recordsLinked to original sources

PubMed2006

Potential impact of steatosis on cytochrome P450 enzymes of human hepatocytes isolated from fatty liver grafts.

Liver grafts discarded for transplantation because of macrosteatosis can constitute a valuable source of human hepatocytes for in vitro metabolic and pharmacotoxicological studies or for therapeutic applications. A condition for using hepatocyte suspensions for these purposes is the preservation of their metabolic competence and, particularly, drug-metabolizing enzymes. A reduction in microsomal cytochrome P450 (P450) activities was observed in fatty livers (>40% steatosis) with respect to normal tissue. Similarly, decreased levels of 7-ethoxycoumarin O-deethylation and testosterone metabolism were observed in human hepatocyte cultures prepared from steatotic liver tissue. To clarify the potential impact of lipid accumulation on human hepatic P450 enzymes, we have used an in vitro model of "cellular steatosis" by incubation of cultured hepatocytes with increasing concentrations (0.25-3 mM) of long-chain free fatty acids (FFA). A dose-dependent accumulation of lipids in the cytosol is induced by FFA mixture. Hepatocytes exposed to 1 mM FFA for 14 h showed lower activity values of CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4 enzymes than nontreated hepatocytes (about 45-65% reduction). This treatment also produced significant decreases in CYP1A2, CYP2A6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4 mRNA to about 55 to 75% of mRNA levels in control cells. Our results suggest that although human hepatocytes isolated from steatotic liver show reduced P450 activities, they are metabolically competent and can be used for drug metabolism studies.

Adult↗

PubMed2005

Acute biliary pancreatitis: does the pancreas change morphologically in the long term?

The objective of the study was to assess by means of magnetic resonance cholangiopancreatography whether acute biliary pancreatitis leads to alterations in pancreatic morphology and the main pancreatic duct; to establish whether such alterations are related to the severity of the acute episode and if they are to be considered as sequelae of the illness or on the contrary the findings constitute diagnostic morphological criteria of chronic pancreatitis. Forty patients with acute biliary pancreatitis were prospectively and consecutively studied, 15 female (37.5%) and 25 male (62.5%). During the acute phase the severity was assessed according to the Atlanta criteria. During subsequent follow-up,we assessed the morphology of the gland and the main pancreatic duct with magnetic resonance cholangiopancreatography 5 years after the episode of pancreatitis, and compared the findings with the findings from a control group. We administered secretin in 16 of the study group cases when visualization of the duct was incomplete or absent. The statistical study of diameter and length showed significant differences in the main pancreatic duct of the case and control groups. No relationship was found between the severity of the illness and morphological alterations of the pancreas after pancreatitis. The statistical analysis, which compared the diameter and the length of the main pancreatic duct before and after the injection of secretin in the study group showed significant differences. We conclude that after acute biliary pancreatitis, in the long term, scarring lesions are detected, which are considered to be sequelae of the acute episode, unrelated to its severity. Secretin stimulation improved visualization of the main pancreatic duct in the magnetic resonance cholangiopancreatography.

Acute Disease↗

PubMed2004

Liver grafts preserved in Celsior solution as source of hepatocytes for drug metabolism studies: comparison with surgical liver biopsies.

Suitability of human liver grafts preserved in Celsior solution (CS) for preparing metabolically competent hepatocyte cultures has been examined. To this end, basal and induced activity and mRNA levels of major hepatic cytochrome P450 (P450) enzymes have been measured. By 24 h in culture, measurable levels of the 10 P450 mRNAs studied were found in all hepatocyte preparations examined, with CYP2E1, CYP2C9, and CYP3A4 mRNAs being the most abundant. Compared with hepatocytes obtained from surgical liver resections (SLRs), lower content of each P450 mRNA was found in hepatocytes from the CS group; however, the relative distribution of individual P450 mRNAs was similar. Similar results were observed after measuring P450 activities. CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2E1, and CYP3A4 activities in hepatocytes from CS-flushed grafts were lower than but comparable with those of cultures prepared from SLRs. No differences in the metabolite profile of testosterone were found. Treatment of hepatocytes from CS-preserved grafts with model P450 inducers shows that 2 microM methylcholanthrene only increased CYP1A1 and CYP1A2 mRNAs (>100-fold over control), 1 mM phenobarbital markedly increased CYP2A6, CYP2B6, and CYP3A4 mRNA content (>7-fold), and 50 microM rifampicin highly increased CYP3A4 mRNA levels (>10-fold), whereas minor effects (<3-fold) were observed in CYP2A6, CYP2B6, and CYP2C9 mRNAs. This induction pattern of P450s was similar, in terms of magnitude, reproducibility, and specificity, to that shown in primary hepatocytes from surgical biopsies. Overall, our results indicate that, cold-preserved in CS, liver grafts constitute a valuable source of human hepatocytes for drug metabolism studies.

Biopsy↗

PubMed2003

Severe recurrent hepatitis C after liver retransplantation for hepatitis C virus-related graft cirrhosis.

An increase in the number of hepatitis C virus (HCV)-infected transplant recipients at need for repeated liver transplantation is anticipated. To date, there is a certain reluctance to accept these patients because of an increased organ shortage, early reports suggesting a poor outcome, and uncertainty regarding the natural history of recurrent hepatitis C in the second graft. The aim of this study is to determine the outcome of patients undergoing retransplantation for HCV-related graft cirrhosis. Of 49 transplant recipients with HCV-related allograft cirrhosis, 31 patients developed decompensation with criteria for retransplantation. Thirteen patients were denied this option. Of the 18 patients accepted, 6 patients died while on the waiting list (5 patients died of graft cirrhosis at a median of 3.2 months of listing), and 12 patients have undergone retransplantation (median, 10 months since HCV cirrhosis). After retransplantation, 8 patients (67%) died at a median of 8 months, and 4 patients (33%) remain alive after 1.9 years of follow-up. Causes and times of death from retransplantation were: surgical complications, n = 3 (perioperative period); HCV cirrhosis of the second graft, n = 2 (at 9 and 54 months); fibrosing cholestatic hepatitis, n = 1 (at 2 years); lymphoproliferative disorder, n = 1 (at 7 months); and endocarditis, n = 1 (at 3.5 years, with underlying cirrhosis). Of the 4 patients alive, fibrosis stages in the last biopsy specimens are stage 1 (n = 1), stage 3 (n = 1), and stage 4 or cirrhosis (n = 1; one patient has not undergone biopsy), despite antiviral therapy. The outcome of retransplantation for HCV cirrhosis of the first graft is very poor because of multiple complications. The severity of recurrent HCV disease in the second graft seems to be related to that observed in the first graft.

Adult↗

PubMed2003

Delayed onset of severe hepatitis C-related liver damage following liver transplantation: a matter of concern?

Although histological hepatitis occurs in the majority of hepatitis C virus (HCV)-infected liver transplant recipients, the natural history is highly variable. Whereas progression to cirrhosis occurs in up to 30% after 3 to 7 years, the disease remains stable in another third of patients, in whom protocol liver biopsies might be avoided. However, there is recent concern that with prolonged follow-up, some patients with initial benign recurrence may develop a late-onset aggressive course. Aims of the study are to determine the incidence and factors associated with this event. Based on yearly protocol biopsies (median, five biopsies; range, three to seven biopsies), we evaluated the histological outcome of 57 HCV type 1b-infected transplant recipients with initial benign recurrence, defined as stable histological state (fibrosis stage F0 or F1) during the first 3 years posttransplantation. Severe late-onset liver damage is defined as progression to F3 or F4 in patients with previous benign recurrence. Potential predictors of this event include demographics, donor-related factors, liver enzyme levels at 1 and 3 (or baseline) years posttransplantation, activity grade and fibrosis stage at 1 and 3 years posttransplantation, nonalcoholic steatohepatitis-related variables occurring within the first 3 years posttransplantation (diabetes, hyperlipidemia, obesity), use of some drugs (renin-angiotensin inhibitors, ursodeoxycholic acid), and the advent of any unusual event. The incidence of severe late-onset liver damage was 35% (n = 20). Twelve transplant recipients progressed to F3, whereas 8 transplant recipients progressed to F4. Sudden histological deterioration was observed on postoperative biopsy 5 in 12 patients; biopsy 6 or 7, in 7 patients; and biopsy 4, in 1 patient. Variables associated with this event in univariate analysis were fibrosis stage and activity grade (and its components) at baseline (P <.0001), recipient female gender (P =.04), alanine aminotransferase (ALT) level at 1 year posttransplantation (P =.02), and aspartate aminotransferase (AST) and ALT levels at baseline (P =.008 and P =.005, respectively). By multivariate analysis, only one variable was retained in the model: fibrosis stage at baseline (relative risk, 11; 95% confidence interval, 3 to 41; P =.0007), whereas AST level almost reached statistical significance (P =.07). In conclusion, delayed HCV-related severe liver damage is not infrequent in transplant recipients with initial benign recurrence, occurring in approximately one third of them. The presence of some degree of fibrosis at baseline appears to predict this sudden change in the natural history of recurrent hepatitis C. Based on these findings, we recommend continuing protocol biopsies and evaluating potential antiviral therapy in transplant recipients with evidence of some fibrosis (even if it is only portal).

Adult↗

PubMed2002

Contribution of donor age to the recent decrease in patient survival among HCV-infected liver transplant recipients.

Recurrent hepatitis occurs in the majority of patients undergoing liver transplantation for hepatitis C virus (HCV) cirrhosis, with progression to cirrhosis in up to 30% after 5 years. Based on these data, a decrease in survival can be anticipated with prolonged follow-up. Furthermore, posttransplantation HCV-fibrosis progression has been shown in recent years to increase. Our aims were (1) to describe the natural history of HCV-infected recipients, particularly to determine whether survival has decreased in recent years; (2) to compare this outcome with that observed in non-HCV-infected cirrhosis controls; and (3) to determine the factors associated with disease severity and survival. Among 522 cirrhotic patients undergoing transplantation between 1991 and 2000, 283 (54%) were infected with HCV. Yearly biopsies were performed in these recipients and at 1 and 5 years in the remainder. With similar follow-up, the percentage of deaths in the HCV(+) group was significantly higher than in the HCV- group (37% vs. 22%, P <.001), and patient survival was lower (77%, 61%, 55% vs. 87%, 76%, 70% at 1, 5, and 7 years, respectively; P =.0001). Although survival has increased in the HCV- group in recent years, it has significantly decreased in HCV recipients (P <.0001). The main cause of death among the latter was decompensated graft cirrhosis (n = 23/105, 22%), whereas that of HCV- patients was infections (n = 10/52, 19%). Reasons for the recent worse outcome in HCV+ recipients include the increased donor age and stronger immunosuppression. In conclusion, patient survival is lower among HCV+ recipients than among HCV- ones and has been decreasing in recent years. The aging of donors is a major contributor to this worse outcome.

Adult↗

PubMed2002

Hepatocellular carcinoma: Can it be considered a controversial indication for liver transplantation in centers with high rates of hepatitis C?

Hepatocellular carcinoma (HCC) is still considered a controversial indication for liver transplantation (LT), mainly because of long waiting times and underlying viral cirrhosis. The goal was to evaluate the outcome of LT in 104 patients with HCC and cirrhosis, mainly hepatitis C virus (HCV)-related, in a center with a short waiting time (median, 105 days). Four groups were formed according to the HCC and HCV status: HCV positive with HCC (group 1, n = 81), HCV negative with HCC (group 2, n = 23), HCV positive without HCC (group 3, n = 200), and HCV negative without HCC (group 4, n = 207). Predictive factors of tumor recurrence were demographics, tumor related (size or number of nodules, capsule, bilobar involvement, vascular or lymphatic invasion, clinical and pathologic TNM staging, pre-LT percutaneous ultrasound-guided ethanol injection or transarterial chemoembolization, alpha-fetoprotein levels), donor and surgery related, and year of transplantation. The same variables and "tumor recurrence (yes/no)" were applied to evaluate the effect on survival. The median follow up was 29 months (range, 0 to 104 months). Patient survival was 70% at 1 year and 59% at 5 years for group 1, 87% at 1 year and 77% at 5 years for group 2, 81% at 1 year and 64% at 5 years for group 3, and 88% at 1 year and 77% at 5 years for group 4 (P =.013). Survival was significantly lower in patients with HCC than in those without (74% and 63% versus 85% and 70%, at 1 and 5 years, respectively; P =.05). The causes of death in those with and without HCC were tumor recurrence (24%) and recurrent HCV (8%) versus sepsis (34%) and recurrent HCV (14%). HCC recurrence occurred in 12 patients (11.5%) at a median of 14 months (range, 3 to 60 months) with a probability increasing from 8% at 1 year to 16% at 5 years. In patients with HCC, tumor recurrence was associated with vascular invasion (P =.0004) by multivariate analysis; variables predictive of survival were donor old age (P =.01), viral-related etiology (P =.02), and tumor recurrence (P =.001). Although LT still remains an adequate indication for HCC in centers with high prevalence of HCV infection and short waiting times, both tumor and HCV-related recurrent diseases hamper significantly the outcomes of these patients.

Adult↗