title: Simvastatin induces activation of the serine-threonine protein kinase AKT and increases survival of isolated human pancreatic islets.
abstract: BACKGROUND
  Pancreatic islets are susceptible to myriad insults that occur during islet isolation and transplantation. Studies demonstrated the role of Akt in regulating pancreatic beta-cell growth and survival. Activation of Akt maintains Bad phosphorylation and prevents its binding to mitochondrial targets, decreases caspase-9 activity, and prevents the translocation of forkhead transcription factors (FKHR). Simvastatin activates Akt in mammalian cells; therefore, we investigated the role of simvastatin on human pancreatic islets (HPI) survival.
  
  
  METHODS
  HPI were treated with simvastatin, with and without LY294002, an inhibitor of phosphoinositide 3-kinase. PI viability was examined with ethidium bromide-acridine orange, and apoptosis was examined using a quantitative assay. Akt, Bad, FKHR phosphorylation, and mitochondrial cytochrome release were analyzed by Western blots. Caspase-9 activity was assessed by a fluorometric assay. A limited number of HPI were transplanted after simvastatin treatment in diabetic NOD-SCID mice.
  
  
  RESULTS
  Low levels of Akt phosphorylation (activation) were demonstrated early after islet isolation. Akt activation; increase in islet viability; and decrease in Bad phosphorylation, cytochrome release, caspase-9 activation, and translocation of FKHR were observed after simvastatin treatment, effects reversed by LY294002. Among recipients of islets without simvastatin, none demonstrated reversal of diabetes after the transplant. In contrast, 58% of the recipients given islets treated with simvastatin remained euglycemic 30 days after the transplant.
  
  
  CONCLUSIONS
  Targeting the survival pathway with simvastatin exerts a cytoprotective effect on isolated PI. Activation of the Akt pathway is a potential new therapeutic approach to reduce loss of functional islet mass to bolster success in clinical islet transplantation.
authors.affiliation: Transplant Center, Division of Transplantation, University of Alabama at Birmingham, 748 Lyons-Harrison Research Building, 701 19th Street South, Birmingham, AL 35294, USA. juan.contreras@ccc.uab.edu.
authors.forename: Juan L
authors.initials: JL
authors.lastname: Contreras
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Smyth
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Bilbao
authors.forename: Carlton J
authors.initials: CJ
authors.lastname: Young
authors.forename: J Anthony
authors.initials: JA
authors.lastname: Thompson
authors.forename: Devin E
authors.initials: DE
authors.lastname: Eckhoff
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D003574:Cytochrome c Group / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000628:therapy; D053222:Fas Ligand Protein; D051858:Forkhead Transcription Factors; D015870:Gene Expression; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D016381:Islets of Langerhans Transplantation; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008928:Mitochondria / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D019821:Simvastatin / Q000494:pharmacology*; D014157:Transcription Factors / Q000378:metabolism; D051025:bcl-Associated Death Protein
chemical_list: D002352:Carrier Proteins; D053453:Caspase 9; D020169:Caspases; D003574:Cytochrome c Group; D053222:Fas Ligand Protein; D051858:Forkhead Transcription Factors; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D019821:Simvastatin; D014157:Transcription Factors; D051025:bcl-Associated Death Protein; C494819:BAD protein, human; C494820:Bad protein, mouse; C505661:FASLG protein, human; C505658:Fasl protein, mouse; C494918:AKT1 protein, human; C506433:CASP9 protein, human; C506434:Casp9 protein, mouse