Effect of cyclosporine on colchicine secretion by a liver canalicular transporter studied in vivo.

The multidrug resistance transport protein is a normal constituent of the liver canalicular membrane, although its function has not been defined in vivo. Colchicine, a multidrug resistance substrate, is eliminated mainly by the liver. Cyclosporine reverses multidrug resistance in vitro, presumably by inhibiting the multidrug resistance transporter. This study assesses biliary colchicine elimination and the effect of cyclosporine on this process. After cyclosporine administration biliary colchicine clearance decreased from 11.6 +/- 0.8 to 2.2 +/- 0.4 ml/min.kg (p less than 0.05), and the colchicine bile/plasma ratio decreased from 166 +/- 9 to 38 +/- 5 (p less than 0.05). Cremophor EL (a cyclosporine vehicle) transiently inhibited biliary colchicine clearance and colchicine bile/plasma ratio, but to a much smaller extent than cyclosporine in vehicle. Biliary cyclosporine clearance was 0.122 and 0.024 ml/min.kg after bolus doses of 2 or 10 mg/kg intravenously, respectively. Cyclosporine bile/plasma ratio was 1.3 to 5.2. When cyclosporine was given 16 hr before colchicine infusion, biliary colchicine clearance decreased 39% (p less than 0.05), and colchicine bile/plasma ratio decreased 51% (p less than 0.05). Thus colchicine is actively secreted into bile and will be useful in the study of the multidrug transporter in vivo. Cyclosporine profoundly inhibits colchicine secretion into bile but is itself mainly metabolized rather than secreted. If competition for a common carrier is the basis for the interaction, then cyclosporine represents a drug that binds to but is not transported by the canalicular transporter.     

Severe, late-onset graft-versus-host disease in a liver transplant recipient documented by chimerism analysis

A 52-year-old liver transplant recipient presented 8 months after transplantation with oral thrush, then 3 days later with oral ulcers and a diffuse rash, and 5 days later with an acutely reduced white blood cell count, rash, fever, and diarrhea. Bone marrow biopsy revealed severe aplasia. Although graft-versus-host disease (GVHD) was considered, the late onset of these symptoms was felt to render this etiology unlikely because GVHD usually occurs 2 to 6 weeks after transplantation. All potentially myelosuppressive medications were discontinued, and the patient was treated with high doses of hematopoietic growth factors. Because his symptoms continued, chimerism analysis was performed, which indicated that 96% of the peripheral blood mononuclear cells were of liver-donor origin. Ultimately, the patient underwent an allogeneic peripheral blood hematopoietic progenitor cell transplant from a human leukocyte antigen-identical brother, but he died 5 days after transplantation of overwhelming Candida kruseii infection. To our knowledge, this is the first chimerism-analysis-documented case of severe acute GVHD presenting so late after liver transplantation. It is of note that the patient had no known risks for GVHD in that he was relatively young and shared only one major human leukocyte antigen with his donor. Consideration should be given to GVHD as a cause of bone marrow aplasia at any time after organ transplantation. Storage of cell pellets from all transplant recipients and donors is highly recommended to facilitate the diagnostic evaluation.     

Transepithelial paracellular leakiness induced by chronic phorbol ester exposure correlates with polyp-like foci and redistribution of protein kinase C-alpha

Although exposure of LLC-PK1 epithelial cell sheets to phorbol esters (TPA) causes a near immediate and total decrease of transepithelial electrical resistance (TER), continuation of exposure for 3 to 4 days results in a tachyphylactic response as TER begins to return to control levels. Recovery of TER is maximal by 5 to 6 days, but reaches only 70 to 80% of control level. A reciprocal change in the transepithelial flux of D-mannitol indicates that the TER decrease is indicative of an increase in tight junction permeability. Exposure of cell sheets to TPA for several days also results in the appearance of multilayered polyp- like foci (PLFs) across the otherwise one cell layer thick cell sheets. The pattern of penetration of the electron dense dye, ruthenium red, from the apical surface, across the tight junction and into the lateral intercellular space indicates that the tight junctions of the cell sheet become uniformly leaky after acute exposure to TPA. However, when exposure is continued for several days, only the junctions of cells in the PLFs manifest leakiness. The decrease in TER following acute TPA exposure correlates with the translocation of protein kinase C-alpha (PKC alpha) into a membrane-associated compartment. With exposure of several days, only a trace of PKC alpha is visible by Western immunoblot, and this is in the membrane-associated compartment. Immunofluorescent microscopy indicates that the trace of PKC alpha seen in the Western immunoblots is ascribable distinctly to cells of the PLFs. Monolayer areas between PLFs show no discernible immunofluorescent signal. The data therefore indicate that tight junction barrier function may be restored in certain areas by the down regulation of PKC alpha from the membrane-associated compartment. Failure to down regulate may result in the paracellular leakiness and abnormal cell architecture of the PLFs. Possible implications of this model for in vivo epithelial tumor promotion are discussed.      

Infection with Listeria monocytogenes following orthotopic liver transplantation: case report and review of the literature

Infection with Listeria monocytogenes is rare with a reported annual incidence of 4.4 cases/million individuals. Epidemiological data have identified certain groups to be higher risk of developing listeriosis, including neonates, pregnant women, adults older than 60 years of age, individuals afflicted with hematologic malignancies, acquired immunodeficicency syndrome, cirrhosis, and those receiving corticosteroid therapy and organ transplants. Within this last group, multiple cases have been described following bone marrow and renal transplantation, but only a few following liver transplantation. We report a case of a 66-year-old woman presenting with Listeria monocytogenes bacteremia at 32 months following orthotopic liver transplantation.