Induction of Alcoholic Ketoacidosis in Mice

Abstract

Chronic alcohol use depletes glycogen stores in the liver and impairs gluconeogenesis, causing decreased glucose availability and increased reliance on fatty acid breakdown. This also alters counterregulatory hormone balance that further increases free fatty acid breakdown and ketone production, resulting in ketoacidosis. The main features of alcoholic ketoacidosis (AKA) are high ketone bodies, low blood bicarbonate levels, and high anion gaps. This metabolic disorder was first reported in 1940s and pathophysiological data were collected from patients taken several decades ago, which helped to lay the foundation for the current understanding of its pathophysiology, diagnosis, and management. Nonetheless, our understanding of AKA is presently limited and has many challenges. To better understand its biochemical and pathophysiological properties, we induced AKA in mice (8-weeks; male) by modifying the clinically relevant NIH alcohol feeding protocol. Compared to mice pair-fed with control diet, mice fed chronic/binge alcohol under a fasting condition developed low blood HCO3− (20.07 mM for pair-fed vs. 13.04 for EtOH-fed mM; p < 0.05; n = 4-6/group), high β-hydroxybutyrate (0.54 mM for pair-fed vs. 3.62 for EtOH-fed mM; p < 0.05), and high pH anion gap (19.7 for pair-fed vs. 33.3 for EtOH-fed; p < 0.05), all of which are hallmarks for AKA. Blood pH was also low (7.32 for pair-fed vs. 7.14 for EtOH-fed; p<0.05) and base excess was more negative, consistent with metabolic acidosis. Mice subjected to a fasting alone exhibited a mild increase in β-hydroxybutyrate. Furthermore, [HCO3−], anion gap, and blood pH remained unchanged in these fasting-alone mice. In mice with AKA, the NADH/NAD+ ratio in the liver was decreased, consistent with the conversion of acetoacetate to β-hydroxybutyrate. These mice also had decreased glucose and insulin levels, consistent with hormonal changes in response to impaired gluconeogenesis and glycogen depletion. The mice also had increased aspartate transaminase AST levels in the blood. Histopathological analysis of the livers revealed diffuse mixed microvesicular and macrovesicular steatosis and mild lobular inflammation in AKA mice. Few acidophilic bodies (necrosis) and ballooning degeneration were seen. Except for the liver, most organs showed no significant difference between the two groups of mice. In summary, AKA mice showed biochemical parameters that are similar to those in humans diagnosed with AKA. The animal model of AKA will be useful for preclinical studies that search and test prevention strategies to alleviate AKA or evaluate the therapeutic effcacy of drug candidates. This work was supported by the grant from the National Institute of Alcohol Abuse and Alcoholism (R21AA028606). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.