title: Influence of CaNa2 EDTA on topical 5-aminolaevulinic acid photodynamic therapy.
abstract: BACKGROUND
  We assessed whether the CaNa2 EDTA could improve the accumulation of protoporphyrin IX (PpIX) and photosensitisation in HEp-2 cells as well as the depth of treatment of skin cancers on the topical 5-Aminolaevulinic acid (5-ALA) PDT.
  
  
  METHODS
  HEp-2 cells were incubated with 5-ALA (0-1 mmol/L) and CaNa2EDTA (0-1 mmol/L) for 4 hours, intracellular protoporphyrin IX content was quantified by extraction, and cell viability was assessed by use of the methyl-tetrazolium (MTT) assay four hours after exposure to light. In comparison with the pictures before and after treatment, depth of treatment could be determined using a Acuson Sequioa 512 phase-array system in paired experiments.
  
  
  RESULTS
  PpIX accumulation increased with increasing extracellular concentrations of ALA (0-1 mmol/L). Adding 1 mmol/L of CaNa2EDTA increased 30% PpIX accumulation over the same period of incubation in the concentration of 1 mmol/L ALA. Significant difference was observed between the 5-ALA alone group and 5-ALA combined CaNa2 EDTA group in the PpIX accumulation (P < 0.01). Cell viability after exposure to light decreased with adding CaNa2 EDTA, a statistical difference in a same fluence above 1.2 J/cm2 between two groups was demonstrated (P < 0.05, P < 0.01 respectively). Depth of treatment of skin cancers were increased in CaNa2 EDTA-treated group.
  
  
  CONCLUSIONS
  CaNa2 EDTA could improve the PpIX accumulation and photosensitisation in HEp-2 cells. Clinically, CaNa2 EDTA could increase the depth of treatment in the cutaneous cancers.
authors.affiliation: Department of Dermatology, Renmin Hospital, Wuhan University, Wuhan 430060, China.
authors.forename: Hui-feng
authors.initials: HF
authors.lastname: Liu
authors.forename: Shi-zheng
authors.initials: SZ
authors.lastname: Xu
authors.forename: Chun-rong
authors.initials: CR
authors.lastname: Zhang
mesh_terms: D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D002470:Cell Survival; D004492:Edetic Acid / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D011524:Protoporphyrins / Q000032:analysis; D012878:Skin Neoplasms / Q000188:drug therapy
chemical_list: D011524:Protoporphyrins; D000622:Aminolevulinic Acid; D004492:Edetic Acid; C028025:protoporphyrin IX