tacrolimus and Hypothermia

Hypothermia is used to preserve organs for transplantation and is the oldest method to protect organs during complex pediatric cardiac surgery. Loss of tissue function and tissue edema are common complications in children undergoing corrective cardiac surgery and heart transplantation. The present study was designed to examine the effects of methylprednisolone and tacrolimus on endothelial cell function and morphology after deep hypothermia and rewarming.. Human umbilical vein endothelial cells were pre-treated with methylprednisolone or tacrolimus, or both, incubated within a specially designed bioreactor or in monolayers, and then exposed to a dynamic cooling and rewarming protocol. Immunocytochemistry, time-lapse video microscopy, cell permeability and adherence assays, and Western blot analysis were performed.. Confluent endothelial cells exposed to hypothermia displayed elongated cell shapes with intercellular gap formation, increased endothelial cell-layer permeability, and loss in adherence. Upon rewarming, however, endothelial cell integrity was restored. Opening and closing of intercellular gaps was dependent on extracellular signal-regulated kinase 1 and 2 (ERK 1/2) activation and connexin 43 expression. The combined treatment with methylprednisolone and tacrolimus inhibited these hypothermia-induced changes.. These results suggest that methylprednisolone and tacrolimus inhibit hypothermia-induced endothelial gap formation by phosphorylated ERK 1/2 inhibition and connexin 43 stabilization. Application of combined drugs that affect multiple targets may therefore be considered as a possible new therapeutic strategy to prevent endothelial dysfunction after hypothermia and rewarming.

Topics: Cell Adhesion; Cell Membrane Permeability; Cell Shape; Cells, Cultured; Connexin 43; Endothelium, Vascular; Glucocorticoids; Humans; Hypothermia; Immunosuppressive Agents; Intercellular Junctions; Methylprednisolone; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Tacrolimus

The synthesis of C32-O-arylethyl ether derivatives of ascomycin that possess equivalent immunosuppressant activity but reduced toxicity, compared to FK-506, is described.

Topics: Administration, Oral; Animals; Calcineurin Inhibitors; Drug Evaluation, Preclinical; Hypothermia; Immunophilins; Immunosuppressive Agents; Inhibitory Concentration 50; Injections, Intravenous; Kidney Diseases; Macrolides; Male; Mice; Mice, Inbred BALB C; Rats; Rats, Sprague-Dawley; Structure-Activity Relationship; T-Lymphocytes; Tacrolimus; Tacrolimus Binding Proteins; Toxicity Tests

A series of C32-O-aralkyl ether derivatives of the FK-506 related macrolide ascomycin have been prepared based on an earlier reported C32-O-cinnamyl ether design. In the present study, the nature of the aryl tethering group was varied in an attempt to improve oral activity. An imidazol-2-yl-methyl tether was found to be superior among those investigated and has resulted in an ascomycin analog, L-733,725, with in vivo immunosuppressive activity comparable to FK-506 but with an improved therapeutic index.

Topics: Animals; Biological Availability; Hypothermia; Imidazoles; Immunophilins; Immunosuppressive Agents; Indicators and Reagents; Kidney; Mice; Mice, Inbred BALB C; Molecular Conformation; Molecular Structure; Neurotoxins; Rats; Structure-Activity Relationship; T-Lymphocytes; Tacrolimus; Tacrolimus Binding Proteins

We examined whether an immunosuppressant, FK506, inhibits delayed neuronal death in the gerbil hippocampal CA1 sector after 5-min forebrain ischemia. After reperfusion, gerbils were injected intravenously with FK506. Gerbils in the early injection group were injected with FK506 immediately after reperfusion, and gerbils in the delayed injection group were injected with FK506 1 or 2 h postischemia. The body temperature of the FK506-treated gerbils in the normothermic group was maintained at 37.5-38.0 degrees C for 2 h postischemia. In the chronic survival group, neuroprotection was assessed after recovery for 45 days. Seven or 45 days after reperfusion, neuronal density in the CA1 was assessed following perfusion fixation. FK506 ameliorated cell death in the CA1 in a dose-dependent manner in every group, although it showed a hypothermic effect. FK506 is neuroprotective against forebrain ischemia in gerbils.

Topics: Animals; Body Weight; Cell Death; Dose-Response Relationship, Drug; Gerbillinae; Hippocampus; Hypothermia; Immunosuppressive Agents; Male; Neurons; Neuroprotective Agents; Prosencephalon; Reperfusion Injury; Tacrolimus; Time Factors