Maria Torres

Bio: Maria Torres is an academic researcher from University of Miami. The author has contributed to research in topics: Liver transplantation & Hepatitis. The author has an hindex of 7, co-authored 8 publications receiving 2127 citations. Previous affiliations of Maria Torres include Oregon Health & Science University.

Results of a Prospective Study of Acute Liver Failure at 17 Tertiary Care Centers in the United States

Abstract: Acetaminophen overdose and idiosyncratic drug reactions have replaced viral hepatitis as the most frequent causes of acute liver failure. The cause of liver failure and coma grade at admission were...

Comparison of tacrolimus with microemulsion cyclosporine as primary immunosuppression in hepatitis C patients after liver transplantation

Abstract: Background. Immunosuppression in patients with hepatitis C virus (HCV) following orthotopic liver transplantation can lead to significant increases in serum viral loads. Our aim was to analyze the effect of a randomized study of two immunosuppressive agents (tacrolimus vs. microemulsion cyclosporine) on the outcome of HCV patients following orthotopic liver transplantation. Methods. From December 1995 to September 1996, 50 adult patients transplanted for HCV cirrhosis were randomly assigned to receive tacrolimus (Prograf) (group 1, 25 patients) or microemulsion cyclosporine (Neoral) (group 2, 24 patients). All patients received a-interferon after transplantation, and the overall steroid doses were no different between the groups. Serum RNA levels were measured by signal amplification of Chiron. Biopsies were taken when transaminases were greater than 23 base line or when there was an inappropriate response to alterations in immunosuppression regimens. Results. There were more episodes of rejection in the Neoral group, but there were no differences in bacterial and viral infections, nor in the rate of HCV recurrence between the two groups. There were seven deaths in group 1 and eight in group 2. Overall patient and graft survival rates in the Prograf and Neoral groups at 18 months were 72 and 68% and 67 and 64%, respectively. Conclusions. (a) Both immunosuppression regimens had similar HCV recurrence rates; (b) there were no differences in bacterial or opportunistic infections; and (c) patient and graft survival was similar between the two groups. End-stage liver disease secondary to hepatitis C is the most common indication for orthotopic liver transplantation. Disease recurrence after transplantation is recognized as a major problem because there are no effective antiviral agents; furthermore, immunosuppression accelerates its course by increasing viral replication (1‐5). There are conflicting reports regarding the role of the two most commonly used immunosuppressive agents, cyclosporine (CsA*) and tacrolimus, impacting the course of the hepatitis C virus (HCV) after transplant. In a randomized prospective study, we compared the effects of these two immunosuppressive agents on patients who underwent liver transplantation for hepatitis C. The new microemulsion form of CsA, Neoral, was used.

Does the heterozygous state of alpha-1 antitrypsin deficiency have a role in chronic liver diseases? Interim results of a large case-control study.

Abstract: Background:The role of the heterozygous PiZ state of alpha-1 antitrypsin deficiency (α1ATD) in the pathogenesis of chronic liver disease (LD) is still a matter of controversy.Aim:To determine the prevalence of α1ATD heterozygote states in a large population of patients with established LD co

HLA-B*5701 genotype is a major determinant of drug-induced liver injury due to flucloxacillin.

Abstract: Drug-induced liver injury (DILI) is an important cause of serious liver disease. The antimicrobial agent flucloxacillin is a common cause of DILI, but the genetic basis for susceptibility remains unclear. We conducted a genome-wide association (GWA) study using 866,399 markers in 51 cases of flucloxacillin DILI and 282 controls matched for sex and ancestry. The GWA showed an association peak in the major histocompatibility complex (MHC) region with the strongest association (P = 8.7 x 10(-33)) seen for rs2395029[G], a marker in complete linkage disequilibrium (LD) with HLA-B*5701. Further MHC genotyping, which included 64 flucloxacillin-tolerant controls, confirmed the association with HLA-B*5701 (OR = 80.6, P = 9.0 x 10(-19)). The association was replicated in a second cohort of 23 cases. In HLA-B*5701 carrier cases, rs10937275 in ST6GAL1 on chromosome 3 also showed genome-wide significance (OR = 4.1, P = 1.4 x 10(-8)). These findings provide new insights into the mechanism of flucloxacillin DILI and have the potential to substantially improve diagnosis of this serious disease.

An official ATS statement: hepatotoxicity of antituberculosis therapy.

Abstract: Drug-induced liver injury (DILI) is a problem of increasing significance, but has been a long-standing concern in the treatment of tuberculosis (TB) infection. The liver has a central role in drug metabolism and detoxification, and is consequently vulnerable to injury. The pathogenesis and types of DILI are presented, ranging from hepatic adaptation to hepatocellular injury. Knowledge of the metabolism of anti-TB medications and of the mechanisms of TB DILI is incomplete. Understanding of TB DILI has been hampered by differences in study populations, definitions of hepatotoxicity, and monitoring and reporting practices. Available data regarding the incidence and severity of TB DILI overall, in selected demographic groups, and in those coinfected with HIV or hepatitis B or C virus are presented. Systematic steps for prevention and management of TB DILI are recommended. These include patient and regimen selection to optimize benefits over risks, effective staff and patient education, ready access to care for patients, good communication among providers, and judicious use of clinical and biochemical monitoring. During treatment of latent TB infection (LTBI) alanine aminotransferase (ALT) monitoring is recommended for those who chronically consume alcohol, take concomitant hepatotoxic drugs, have viral hepatitis or other preexisting liver disease or abnormal baseline ALT, have experienced prior isoniazid hepatitis, are pregnant or are within 3 months postpartum. During treatment of TB disease, in addition to these individuals, patients with HIV infection should have ALT monitoring. Some experts recommend biochemical monitoring for those older than 35 years. Treatment should be interrupted and, generally, a modified or alternative regimen used for those with ALT elevation more than three times the upper limit of normal (ULN) in the presence of hepatitis symptoms and/or jaundice, or five times the ULN in the absence of symptoms. Priorities for future studies to develop safer treatments for LTBI and for TB disease are presented.

Idiosyncratic drug hepatotoxicity

Abstract: The occurrence of idiosyncratic drug hepatotoxicity is a major problem in all phases of clinical drug development and the most frequent cause of post-marketing warnings and withdrawals This review examines the clinical signatures of this problem, signals predictive of its occurrence (particularly of more frequent, reversible, low-grade injury) and the role of monitoring in prevention by examining several recent examples (for example, troglitazone) In addition, the failure of preclinical toxicology to predict idiosyncratic reactions, and what can be done to improve this problem, is discussed Finally, our current understanding of the pathophysiology of experimental drug hepatotoxicity is examined, focusing on acetaminophen, particularly with respect to the role of the innate immune system and control of cell-death pathways, which might provide targets for exploration and identification of risk factors and mechanisms in humans