Cellular damage to human hepatocytes through repeated application of 5-aminolevulinic acid

J Hepatol. 2003 Apr;38(4):476-82. doi: 10.1016/s0168-8278(02)00454-3.


Background/aims: 5-Aminolevulinic acid (ALA), a precursor of porphyrins is used for photodynamic diagnosis and therapy within topical or systemic applications. A potential toxic effect on the human liver is of major interest and therefore we investigated the impact of a repeated application of ALA without illumination on cultures of human hepatocytes.

Methods: After ALA treatment of hepatocytes in vitro the porphyrin synthesis, albumin secretion, liver-specific enzyme release, and malondialdehyde levels were determined. In order to reduce levels of reactive oxygen substances, mannitol and the antioxidant enzymes superoxide dismutase and catalase were supplemented.

Results: Porphyrin biosynthesis by human hepatocytes in vitro was repeatedly stimulated by ALA (0.001-1.0 mM), which was indicated by an accumulation of protoporphyrin IX. A repetitive treatment (up to four times) of hepatocytes with ALA resulted in an impairment of the hepatic function and viability, depending on the ALA concentration (0.1-1.0 mM) and frequency of application (2-3 times). This was also accompanied by increased malondialdehyde levels indicating enhanced lipid peroxidation. Only superoxide dismutase was able to reduce cellular damage and prevent specific function.

Conclusions: Repeated, not single, ALA treatment without illumination may cause deleterious effects to the liver, which are mediated by oxygen radicals and inhibited by an antioxidant.

MeSH terms

  • Aminolevulinic Acid / pharmacology*
  • Antioxidants / pharmacology
  • Cell Survival / drug effects
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Hepatocytes / cytology
  • Hepatocytes / drug effects*
  • Hepatocytes / metabolism*
  • Humans
  • In Vitro Techniques
  • Lipid Peroxidation / drug effects
  • Male
  • Photosensitizing Agents / pharmacology*
  • Porphyrins / biosynthesis
  • Reactive Oxygen Species / metabolism
  • Superoxide Dismutase / pharmacology


  • Antioxidants
  • Photosensitizing Agents
  • Porphyrins
  • Reactive Oxygen Species
  • Aminolevulinic Acid
  • Superoxide Dismutase