Use of mycophenolate mofetil in the experimental allo-transplantation of hepatocytes in rats with fulminant hepatic failure.

AIM: The aim of the study was to evaluate the beneficial effect of mycophenolate mofetil (MMF) as an immunosuppressive agent for experimental transplantation of hepatocytes in rats with fulminant hepatic failure (FHF). MATERIALS AND METHODS: Six Wistar rats were used as donors and 40 Lewis rats at recipients, including four groups of 10 animals each. Group A received no treatment; Group B, cyclosporine (20 mg/kg days 0-5 and 10 mg/kg days 6-15); Group C, MMF (12 mg/kg per os every day); and Group D, MMF (23 mg/kg per os every day). Hepatocytes were transplanted intrasplenically. Animals were followed for 15 days. RESULTS: The survival rates for Group A were maximum 72 h, whereas Groups B, C, and D showed 50%, 70%, and 80%, respectively. Biochemical evaluation and histology showed satisfactory function and engraftment, respectively. CONCLUSION: The use of MMF in this experimental model yielded safe, satisfactory immunosuppression especially at the dose of 23 mg/kg.

Increased activation of the coagulation and fibrinolytic systems leads to hemorrhagic complications during left ventricular assist implantation.

BACKGROUND: Left ventricular assist devices (LVADs) have provided a new therapeutic option for patients with end-stage heart failure. Despite advances in device design, there remains an apparent bleeding diathesis, which leads to increased transfusion requirements and reoperative rates. The purpose of our study was to examine the abnormalities that might contribute to these clinical sequelae. METHODS AND RESULTS: To separate the effects of cardiopulmonary bypass (CPB), eight patients undergoing coronary revascularization (CABG) were compared with seven LVAD (TCI HeartMate) recipients intraoperatively and 2 hours postoperatively. We evaluated several well-characterized indexes of platelet activation: platelet count, platelet factor 4 (PF4), beta-thromboglobulin (beta-TG), and thromboxane B2 (TXB2). We also measured activation of thrombin: thrombin-antithrombin III (TAT), prothrombin fragment 1 + 2 (F1 + 2), and fibrinopeptide A (FPA) as well as markers of fibrinolysis: plasmin-alpha 2-antiplasmin (PAP) and D-dimer. Patterns of intraoperative platelet adhesion and activation were not statistically different in the CABG control and LVAD groups. In the immediate postoperative period, however, there was significant release of PF4 and beta-TG and generation of TXB2. Compared with the CABG controls (TAT, 26 +/- 8 micrograms/L; F1 + 2, 4 +/- 1 nmol/L; mean +/- SEM), there was a significant increase in TAT (380 +/- 112 micrograms/L) and F1 + 2 (23 +/- 4 nmol/L) in LVAD patients 2 hours after surgery. Furthermore, a sharp rise in FPA was noted 20 minutes after LVAD initiation (CABG, 8 +/- 4 ng/mL; LVAD, 235 +/- 63 ng/mL; P < .05). A concomitant increase in both PAP (CABG, 987 +/- 129 micrograms/L; LVAD 3456 +/- 721 micrograms/L; P < .05) and D-dimer (CABG, 1678 +/- 416 ng/mL; LVAD, 15243 +/- 4682 ng/mL; P < .05) was observed. CONCLUSIONS: The additive effects of CPB and LVAD lead to platelet activation as well as elevation of markers of in vivo thrombin generation, fibrinogen cleavage, and fibrinolytic activity. The etiology of these findings may be secondary to the LVAD surface, flow characteristics, and/or operative procedure. Nevertheless, platelet alterations and exaggerated activation of the coagulation and fibrinolytic systems may contribute to the clinically observed hemostatic defect.