Non-Invasive Assessment of Human Hepatic Mitochondrial Function through the ¹³C-Methionine Breath Test

Abstract

Background: Mitochondrial metabolism is essential for liver function, and the availability of simple and non-invasive tests able to assess hepatic mitochondrial function could be extremely useful. Since the amino acid methionine is mostly oxidized by liver mitochondria, we investigated the feasibility of a breath test with ¹³C-methionine in healthy subjects to assess hepatic mitochondrial function before and after ethanol-induced oxidative stress. Methods: Twenty healthy male volunteers received 2 mg/kg body weight [methyl-¹³C]-methionine. Breath ¹³CO₂ enrichment was measured at base line and every 15 min thereafter for 180 min. Forty-eight hours later the test was repeated 30 min after the ingestion of ethanol (0.3 g/kg body weight). Results: After oral administration of methionine, ¹³CO₂