Short chain fatty acid-induced central hyperventilation in rabbits

Area of Science:

• Neuroscience
• Toxicology
• Biochemistry

Background:

• Short chain fatty acids (SCFAs), including octanoate, are elevated in patients with hepatic encephalopathies and Reye syndrome.
• The precise role of SCFAs in the pathogenesis of these neurological disorders remains unclear.

Purpose of the Study:

• To investigate the potential neurotoxic effects of octanoate, a representative SCFA, in a preclinical model.
• To determine if octanoate infusion can replicate key clinical and chemical abnormalities observed in hepatic encephalopathies and Reye syndrome.

Main Methods:

• Sodium octanoate was infused intravenously into rabbits over 4 hours at a concentration of 0.2 M.
• Blood and brain tissue levels of octanoate were measured.
• Physiological parameters including respiration, blood gases, ammonia, and lactate levels were monitored.

Main Results:

• Octanoate infusion resulted in significant increases in blood and brain octanoate concentrations (200-700 µmol/L).
• Animals exhibited marked hyperventilation, leading to mild respiratory alkalosis.
• Significant hyperammonemia and lactic acidemia were observed in octanoate-infused rabbits.

Conclusions:

• Short chain fatty acids, exemplified by octanoate, may act as endogenous neurotoxins in conditions like hepatic encephalopathy and Reye syndrome.
• The observed central hyperventilation in these disorders could be attributed to the neurotoxic impact of SCFAs.