Xenobiotics Triggering Acute Intermittent Porphyria and Their Effect on Mouse Brain Respiratory Complexes

TL;DR

This study explores how certain chemicals affect mitochondrial function in mice, potentially shedding light on the mechanisms behind a type of porphyria called acute intermittent porphyria.

Contribution

The study reveals specific effects of porphyrinogenic agents on mitochondrial respiratory complexes in mice, offering new insights into AIP pathophysiology.

Findings

Isoflurane and sevoflurane had contrasting effects on respiratory complex activities.

AIA, ethanol, and ALA decreased complex I–III and II activity.

Barbital and ALA increased complex IV activity, while sevoflurane decreased it.

Abstract

Heme enzyme dysfunction causes a group of diseases called porphyrias. Particularly, a decrease in porphobilinogen deaminase, involved in the third step of heme biosynthesis, leads to acute intermittent porphyria (AIP). Considering our previous works demonstrating the multiplicity of brain metabolisms affected by porphyrinogenic agents, this study aimed to elucidate whether they cause any alteration on the mitochondrial respiratory chain. The activities of respiratory chain complexes (I to IV) were measured in encephalon mitochondria of CF1 male mice receiving volatile anesthetics: isoflurane (2 mL/kg) and sevoflurane (1.5 mL/kg), ethanol (30%), allylisopropylacetamide (AIA) (350 mg/kg), and barbital (167 mg/kg). Moreover, they were compared versus animals with pathological levels of 5-aminolevulinic acid (ALA, 40 mg/kg). Complex I–III activity was induced by isoflurane and decreased by AIA, ethanol, and ALA. Complex II–III activity was increased by sevoflurane and decreased by isoflurane and AIA. Complex II activity was increased by sevoflurane and barbital and decreased by AIA, ethanol, and ALA. Complex IV activity was increased by barbital and ALA and decreased by sevoflurane. The damage to the respiratory chain by ALA could be reflecting the pathophysiological condition of patients with AIP. Better understanding the broad effect of porphyrinogenic drugs and the mechanisms acting on the onset of AIP is vital in translational medicine.

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