Profiling of Urinary Glucuronidated Bile Acids across Age Groups

Area of Science:

• Biochemistry
• Pediatrics
• Pharmacology

Background:

• Bile acids are crucial for digestion and signaling.
• Bile acid metabolism undergoes significant changes during early development.
• Glucuronidation is a key metabolic pathway for bile acids.

Purpose of the Study:

• To investigate age-dependent changes in urinary excretion of bile acid 3-glucuronides.
• To understand the role of gut microbiota and hepatic enzyme activity in this process.
• To characterize the forms of bile acid 3-glucuronides excreted in infants and children.

Main Methods:

• Analysis of urinary bile acid profiles in different age groups.
• Quantification of glucuronidated bile acids, specifically at the C-3 position.
• Correlation of excretion patterns with the establishment of gut bacterial flora and hepatic enzyme levels.

Main Results:

• Bile acid 3-glucuronides represented 0.5% of urinary bile acids in neonates, plateauing by 1-3 years.
• Secretion of 3-glucuronides from secondary bile acids began at 3 months, coinciding with gut flora development.
• A significant portion of these glucuronides were non-amidated.
• Uridine 5 -diphospho-glucuronosyltransferase (UGT) activity varied with age, showing higher activity towards non-amidated bile acids.

Conclusions:

• Urinary bile acid 3-glucuronide excretion exhibits distinct age-dependent patterns.
• Gut microbiota establishment and dynamic hepatic UGT activity influence bile acid metabolism in early life.
• UGTs display differential activity towards amidated and non-amidated bile acids, impacting their excretion.