title: Hypertonicity induces injury to cultured human endothelium: attenuation by glutamine.
abstract: BACKGROUND
  Although most preservation solutions as well as some cardioplegic solutions used for organ storage and transplantation are hypertonic, the effects of extracellular hypertonicity on endothelium are not well established. Aims of this study were to evaluate the response of cultured human saphenous vein endothelial cells to extracellular hypertonicity and to investigate the role of the amino acid glutamine in preventing endothelial damage in vitro.
  
  
  METHODS
  Eight distinct strains of human saphenous vein endothelial cells were studied. Hypertonic (350 and 400 mosm/kg) media were obtained by supplementing culture medium with sucrose. Cell viability was assessed in the absence or the presence of glutamine through the determination of cell number and protein content of the cultures. Confocal microscopy of cells loaded with the fluorescent dye calcein was also performed.
  
  
  RESULTS
  Exposure of human saphenous vein endothelial cells to hypertonic media without glutamine caused significant cell loss within 30 minutes. Cell loss progressed steadily during incubation and after 6 hours reached 50% at 350 mosm/kg and 65% at 400 mosm/kg. In the presence of 2 mmol/L glutamine, endothelial damage was completely prevented at 350 mosm/kg and significantly lessened at 400 mosm/kg compared with glutamine-free media. Confocal microscopy showed that most hypertonicity-treated cells exhibited the typical features of an apoptotic death and confirmed the osmoprotective effect of glutamine.
  
  
  CONCLUSIONS
  These results indicate that the supplementation of hypertonic storage solutions with glutamine might exert a partial osmoprotective effect and suggest that the relationship between endothelial damage and tonicity of storage and cardioplegic solutions should be carefully investigated.
authors.affiliation: Department of Cardiac Surgery, Centro Cardiologico, Fondazione I. Monzino, IRCCS, University of Milan, Italy. corallo@imiucca.csi.unimi.it
authors.forename: A
authors.initials: A
authors.lastname: Parolari
authors.forename: R
authors.initials: R
authors.lastname: Sala
authors.forename: C
authors.initials: C
authors.lastname: Antona
authors.forename: O
authors.initials: O
authors.lastname: Bussolati
authors.forename: F
authors.initials: F
authors.lastname: Alamanni
authors.forename: P
authors.initials: P
authors.lastname: Mezzadri
authors.forename: V
authors.initials: V
authors.lastname: Dall'Asta
authors.forename: G C
authors.initials: GC
authors.lastname: Gazzola
authors.forename: P
authors.initials: P
authors.lastname: Biglioli
mesh_terms: D000368:Aged; D017209:Apoptosis; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000473:pathology; D005973:Glutamine / Q000494:pharmacology*; D006801:Humans; D006982:Hypertonic Solutions / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009997:Osmotic Pressure; D012501:Saphenous Vein / Q000187:drug effects
chemical_list: D003470:Culture Media; D006982:Hypertonic Solutions; D005973:Glutamine