Accumulation of porphyrins in plasma and tissues of dogs after δ-aminolevulinic acid administration: Implications for photodynamic therapy

Norman G. Eggeri, Massoud Motamedi, Mariela Pow-Sang, Eduardo Orihuela, Karl E. Anderson

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

Protoporphyrin accumulates in tissues after administration of δ-aminolevulinic acid, and can be used as a photosensitizer for photodynamic therapy. To determine the distribution of porphyrins in a large animal model after administration of this porphyrin precursor, δ-aminolevulinic acid was administered to anesthetized dogs (100 mg/kg body weight intravenously) and porphyrin concentrations were measured in tissues (liver, pancreas, prostate, bladder, muscle and skin), plasma and urine for 6-10 h. Porphyrins increased markedly (up to 50-fold) in plasma within 1 h, were still markedly increased at 8 h, and consisted mostly of coproporphyrin III and protoporphyrin. Tissue porphyrin concentrations increased more slowly, were highest in liver, pancreas and prostate 7-10 h after δ-aminolevulinic acid administration, and were predominantly protoporphyrin. Maximum porphyrin concentrations in liver were 3- and 4-fold higher than in pancreas and prostate, respectively. Urinary δ-aminolevulinic acid excretion increased and was greatest 2-4 h after dosing; urinary porphobilinogen and porphyrins increased more gradually and remained increased up to at least 8 h. Coproporphyrin III was the predominant porphyrin in urine at all times, but hepta-, hexa- and pentacarboxyl porphyrins increased proportionally after administration of δ-aminolevulinic acid. These results indicate that porphyrins accumulate in plasma as well as tissues and urine after administration of δ-aminolevulinic acid, and may contribute to tumor necrosis during photodynamic therapy.

Original languageEnglish (US)
Pages (from-to)362-370
Number of pages9
JournalPharmacology
Volume52
Issue number6
DOIs
StatePublished - Jan 1 1996

Keywords

  • Cancer
  • Photodynamic therapy
  • Porphyrins
  • Protoporphyrin
  • δ-Aminolevulinic acid

ASJC Scopus subject areas

  • Pharmacology

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