Altered gallbladder bile acidification with long-term total parenteral nutrition

Area of Science:

• Gastroenterology
• Biliary Physiology
• Surgical Nutrition

Background:

• Gallbladder acidification and concentration are vital for preventing gallstone formation.
• Altered bile pH is implicated in pigment gallstone development.
• This study investigates gallbladder changes in a model of TPN-associated pigment gallstones.

Purpose of the Study:

• To determine the impact of long-term total parenteral nutrition (TPN) on gallbladder bile composition.
• To assess changes in gallbladder pH, electrolytes, and lipids in a TPN-associated gallstone model.
• To explore the role of altered gallbladder acidification in gallstone formation.

Main Methods:

• Miniswine were subjected to long-term TPN (21-27 days) or fed a control diet with saline infusion.
• Gallbladder and hepatic bile were analyzed for electrolytes, lipids, pH, and pCO2.
• Changes in bile composition were compared between TPN and control groups.

Main Results:

• TPN pigs exhibited higher gallbladder pH and lower hydrogen ion concentration ([H+]) compared to controls.
• Gallbladder bile pCO2, sodium (Na), and potassium levels were higher in controls.
• Biliary lipids, including bile salts (BS), phospholipids, and cholesterol, were reduced in TPN-fed pigs.

Conclusions:

• Long-term TPN results in less acidified and concentrated gallbladder bile, characterized by higher pH and lower [H+], [Na], and [BS].
• Absence of enteral stimulation during TPN may impair gallbladder acidification.
• Periods without oral intake, as seen in TPN, could promote gallstone formation by increasing gallbladder bile pH.