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

Area of Science:

• Biochemistry
• Neuroscience
• Toxicology

Background:

• Heme enzyme dysfunction leads to porphyrias, including acute intermittent porphyria (AIP), caused by decreased porphobilinogen deaminase.
• Previous studies show porphyrinogenic agents affect brain metabolism.

Purpose of the Study:

• To investigate the impact of porphyrinogenic agents on the mitochondrial respiratory chain in the brain.
• To determine if these agents alter the activity of respiratory chain complexes I-IV.

Main Methods:

• Mice (CF1) were administered volatile anesthetics (isoflurane, sevoflurane), ethanol, allylisopropylacetamide (AIA), barbital, or 5-aminolevulinic acid (ALA).
• Mitochondrial respiratory chain complex activities (I-IV) were measured in mouse brains.

Main Results:

• Isoflurane induced Complex I-III activity; AIA, ethanol, and ALA decreased it.
• Sevoflurane increased Complex II-III and II activity; isoflurane and AIA decreased Complex II-III activity.
• AIA, ethanol, and ALA decreased Complex II activity; sevoflurane decreased Complex IV activity.
• Barbital increased Complex II and IV activity; ALA increased Complex IV activity.

Conclusions:

• Porphyrinogenic drugs and ALA significantly alter mitochondrial respiratory chain complex activities in the brain.
• ALA-induced mitochondrial damage may mimic the pathophysiology of AIP.
• Understanding these mechanisms is crucial for translational medicine in AIP.