Hypoalbuminemia in inflammatory disorders is not an infrequent finding. However, little is known about albumin synthesis in these patients. In the present study we have measured the albumin synthesis in four patients with inflammatory diseases using the ['4Cjcarbonate technique. Because inflammation causes a decreased albumin synthesis and this decreased synthesis could not be related to a reduced amino acid supply, we have also examined the possible molecular mechanisms of reduced albumin synthesis during inflammation using in vivo and in vitro experiments in rats. In rats with turpentine-induced inflammation, serum albumin concentration and liver albumin mRNA level were markedly decreased. These changes could not be reproduced by administration of fibrinogen-, or fibrin-degradation products, or several hormones, such as corticosteroids, growth hormone, and adrenaline. However, monocytic products, especially interleukin 1, postulated to be important mediators of the inflammatory response, reduced albumin synthesis and liver albumin messenger RNA content but not total protein synthesis in rats in vivo and in primary cultures of rat hepatocytes. These findings suggest that monocytic products play an important role in reduced albumin synthesis during inflammation.
Aplastic anemia is a rare complication of liver transplantation (<1%). However, an increasing number of cases of aplastic anemia have been recently reported when liver transplantation is performed for non-A, non-B, non-C fulminant hepatic failure. The aim of this study is to reevaluate the importance and the incidence of aplastic anemia after liver transplantation for non-A, non-B, non-C fulminant hepatic failure, and to propose preventive measures, diagnostic and management guidelines to try to reduce the incidence, morbidity and mortality associated with this complication. In this report a case of aplastic anemia after liver transplantation for non-A, non-B, non-C fulminant hepatic failure is described. In addition, the pertinent literature on aplastic anemia after liver transplantation, since the first description of that complication in 1987, is reviewed. A 20-year-old woman developed aplastic anemia 14 weeks after liver transplantation for fulminant non-A, non-B, non-C hepatitis. After failure of G-CSF treatment, she was treated with intensive immunosuppression (FK 506, ATG, high-dose steroids). She is well 1 year post-transplantation, with normal liver tests and with bone marrow recovery. Through a Medline literature search (1988-1999), we identified 30 additional cases of aplastic anemia following liver transplantation for non-A, non-B, non-C fulminant hepatic failure. Of all liver transplantations performed for that indication at five participating centers, the mean incidence of aplastic anemia was 23.2%. Mean age was 10 years (1.2-29) and the male/female ratio was 4.6. For treating aplastic anemia, different modalities were used: ATG ( n=12), ALG ( n=1), OKT 3 ( n=1), G-CSF ( n=6), a 6-HLA-compatible bone marrow transplantation ( n=3), and none ( n=12). The mortality rate remains high (39%), with infections and bleeding as the two most frequent causes of death. Based on this literature review, we conclude that aplastic anemia is a relatively common complication of liver transplantation for non-A, non-B, non-C fulminant hepatic failure in children and young adults. An unknown viral agent operating through immune-mediated mechanisms is probably responsible. The myelotoxic environment inherent to transplantation (e.g. azathioprine, trimethoprim) probably has a cumulative effect. Preventive measures (e.g. not using myelotoxic drugs) should be adopted in high-risk children and young adults transplanted for non-A, non-B, non-C fulminant hepatic failure. Early detection of bone marrow depression, a low threshold for performing a bone marrow biopsy, and prompt treatment are pivotal. Intensive standard supportive care with broad-spectrum antibiotics and anti-fungal agents is essential during phases of pancytopenia. Although spontaneous recovery has been described under maintenance immunosuppression, increased immunosuppression, in particular with ATG, may reverse the aplastic anemia and promote bone marrow recovery. In unresponsive patients, six-HLA-identical bone marrow transplantation has been successful.
Mycophenolate mofetil (MMF), the morpholinoethyl ester of mycophenolic acid (MPA), is currently used as an immunosuppressive agent in kidney transplant recipients. After oral administration, MMF is hydrolysed to MPA, the active compound, which is a potent inhibitor of inosine monophosphate dehydrogenase (IMP-DH). Inhibition of this enzyme results in a depletion of the intracellular GTP and dGTP pools. MPA has been shown to inhibit the replication of a number of viruses, including arena viruses (Junin and Tacaribe), yellow fever virus, reovirus-1, parainfluenza-3 virus, Coxsackie B4 virus, Epstein-Barr virus and human immunodeficiency virus. To examine whether MPA also has an inhibitory effect on HBV replication, experiments were performed using cultures of primary human hepatocytes and HBV-transfected, HepG2 2.2.15 cells. After in vitro infection with HBV in human hepatocytes, HBV covalently-closed-circular (ccc) DNA and HBV mRNAs were detectable in the cells during the 10 days following infection. HBV DNA and hepatitis B surface antigen (HBsAg) were also secreted into the culture medium. In the presence of 10 microg ml-1 MPA (the therapeutic serum level of MPA as an immunosuppressive agent) in culture medium, HBV ccc DNA and HBV mRNAs became undetectable 5 days after treatment was started. The secretion of HBV DNA and HBsAg into the medium was also markedly reduced. No cytotoxic effect of the drug was noted during the experiments. The effect of MPA on HBV replication was abolished by the presence of guanosine (50 microg ml-1). In HepG2 2.2.15 cells (which contain an integrated tandem dimer of the HBV genome), MPA treatment had no significant inhibitory effect on the secretion of HBV DNA and HBsAg into the culture medium. HBV ccc DNA and HBV mRNAs in HepG2 2.2.15 cells were also not affected. The observed effect of MPA on HBV replication in primary human hepatocyte cultures may involve only episomal replication and may have clinical implications, especially before integration of HBV DNA into the host genome.
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