title: Effect of Storage Temperature on Structure and Function of Cultured Human Oral Keratinocytes.
abstract: OBJECTIVE
  To assess the effect of storage temperature on the viability, phenotype, metabolism, and morphology of cultured human oral keratinocytes (HOK).
  
  
  METHODS
  Cultured HOK cells were stored in HEPES- and sodium bicarbonate-buffered Minimum Essential Medium (MEM) at nine temperatures in approximately 4 °C increments from 4 °C to 37 °C for seven days. Cells were characterized for viability by calcein fluorescence, phenotype retention by immunocytochemistry, metabolic parameters (pH, glucose, lactate, and O2) within the storage medium by blood gas analysis, and morphology by scanning electron microscopy and light microscopy.
  
  
  RESULTS
  Relative to the cultured, but non-stored control cells, a high percentage of viable cells were retained only in the 12 °C and 16 °C storage groups (85% ± 13% and 68% ± 10%, respectively). Expression of ABCG2, Bmi1, C/EBPδ, PCNA, cytokeratin 18, and caspase-3 were preserved after storage in the 5 groups between 4 °C and 20 °C, compared to the non-stored control. Glucose, pH and pO2 in the storage medium declined, whereas lactate increased with increasing storage temperature. Morphology was best preserved following storage of the three groups between 12 °C, 16 °C, and 20 °C.
  
  
  CONCLUSIONS
  We conclude that storage temperatures of 12 °C and 16 °C were optimal for maintenance of cell viability, phenotype, and morphology of cultured HOK. The storage method described in the present study may be applicable for other cell types and tissues; thus its significance may extend beyond HOK and the field of ophthalmology.
authors.affiliation: Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway; Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America.
authors.forename: Rakibul
authors.initials: R
authors.lastname: Islam
authors.affiliation: Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.
authors.forename: Catherine
authors.initials: C
authors.lastname: Jackson
authors.affiliation: Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.
authors.forename: Jon R
authors.initials: JR
authors.lastname: Eidet
authors.affiliation: Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway.
authors.forename: Edward B
authors.initials: EB
authors.lastname: Messelt
authors.affiliation: Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America.
authors.forename: Rima Maria
authors.initials: RM
authors.lastname: Corraya
authors.affiliation: Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.
authors.forename: Torstein
authors.initials: T
authors.lastname: Lyberg
authors.affiliation: Integrative Regenerative Medicine Centre, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: May
authors.initials: M
authors.lastname: Griffith
authors.affiliation: Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America.
authors.forename: Darlene A
authors.initials: DA
authors.lastname: Dartt
authors.affiliation: Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway; Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America.
authors.forename: Tor P
authors.initials: TP
authors.lastname: Utheim
mesh_terms: D048430:Cell Shape; D002470:Cell Survival; D002478:Cells, Cultured; D005452:Fluoresceins / Q000378:metabolism; D005453:Fluorescence; D005470:Fluorometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D019344:Lactic Acid / Q000378:metabolism; D055442:Metabolome; D009055:Mouth / Q000166:cytology; D010100:Oxygen / Q000378:metabolism; D010313:Partial Pressure; D010641:Phenotype; D011309:Preservation, Biological; D013696:Temperature
chemical_list: D005452:Fluoresceins; C085925:calcein AM; D019344:Lactic Acid; D010100:Oxygen