title: A simplified technique for the cryopreservation of vein allografts.
abstract: OBJECTIVE
  we assessed the effects of cryopreservation on smooth-muscle cell injury in human vein.
  
  
  METHODS
  long saphenous vein was collected during surgery and cryopreserved. Smooth-muscle cell damage was assessed after thawing by in situ detection of fragmented DNA. The presence of cryoprotectant (10% dimethyl sulphoxide, DMSO), cooling and warming rates, and the rate of cryoprotectant removal after thawing were examined.
  
  
  RESULTS
  control veins exhibited damage in 8.5% (95% confidence interval (CI) 4.7 to 13.4%,n=13) of smooth-muscle cells compared with 27.7% (95% CI 23.2 to 32.4%, n=115) in vein frozen in 10% DMSO (p=0.001). In the presence of DMSO, damage to smooth-muscle cells was independent of the rates of cooling (p=0.72) and warming (p=0.45). The rate of dilution to remove the cryoprotectant after thawing also had no effect on cell damage (p=0.64). In the absence of cryoprotectant, cell damage was doubled to approximately 50% by slow rather than rapid warming (p=0.01).
  
  
  CONCLUSIONS
  cooling rate, and the presence of a cryoprotectant, has little effect on smooth-muscle damage, provided that the tissue is warmed rapidly. Slow warming, in the absence of DMSO, causes substantial damage. These results suggest that simplified methods of vein cryopreservation are feasible.
authors.affiliation: Department of Vascular Surgery, Southmead Hospital, Bristol, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Ruddle
authors.forename: S J
authors.initials: SJ
authors.lastname: George
authors.forename: W J
authors.initials: WJ
authors.lastname: Armitage
authors.forename: E L
authors.initials: EL
authors.lastname: Alexander
authors.forename: D C
authors.initials: DC
authors.lastname: Mitchell
mesh_terms: D016001:Confidence Intervals; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000032:analysis; D046508:Culture Techniques; D053938:DNA Fragmentation; D004121:Dimethyl Sulfoxide / Q000032:analysis; D005615:Freezing; D006801:Humans; D020287:In Situ Nick-End Labeling; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D012501:Saphenous Vein / Q000473:pathology / Q000637:transplantation; D013997:Time Factors; D014184:Transplantation, Homologous
chemical_list: D003451:Cryoprotective Agents; D004121:Dimethyl Sulfoxide