Bile is almost entirely water, yet tiny water channels may help decide whether it flows normally, concentrates safely, or contributes to disease. This review asks whether those channels could become treatment targets.

Bile is made of about ninety-five percent water, and it moves through the liver, bile ducts, gallbladder, and intestine. Aquaporins are membrane proteins that facilitate the movement of water and some small neutral solutes across cell membranes. The review links these water channels to several jobs: helping form liver bile, rearranging bile in the ducts, and moving water in both directions in the gallbladder so bile can become concentrated.

The review also links aquaporins with bile-related disorders, including diseases in which bile flow is blocked and cholesterol gallstones, while pointing toward compounds that might change or block these channels. The review brings together what is known about these water channels in health and disease, then considers ways to change their activity as possible additional treatment targets.

Aquaporin function is relevant in both health and disease, while possible ways to modulate these channels are being considered as additional therapeutic targets. Bile fluid formation begins at the membrane of liver cells as a process involving dissolved substances and water.

Substances are actively secreted into tiny channels, creating the force that drives water secretion alongside them. But bile can still flow when bile acids are absent or low. Another part of the flow comes from the active secretion of dissolved salts and other charged substances.

Bile formation depends on water moving in two directions: one channel brings water into liver cells from the bloodstream, while another releases it into the bile passage. Glucagon helps by moving the release channels to the cell surface, linking hormone signals directly to bile secretion.

Cells lining the bile ducts release charged substances into the duct. Those substances create the main force that moves water through AQP1 into the bile. AQP1 carries water into the duct during ordinary bile formation and during hormone-regulated formation.

It is also stored in small membrane compartments that can be inserted into the cell surface when secretin signals the cell. Water channels on the blood-facing side help keep duct bile close to the concentration of the surrounding fluid, with bile water originating from the blood-vessel network around the ducts.

This matters because a hormone signal can turn duct cells into water-moving cells: it brings salt-moving machinery to the duct-facing surface, and the resulting salt buildup pulls water from the blood into bile. But the gallbladder story is less settled.

The exact importance of AQP1 and AQP8 remains debated, and studies have reported different results. One study found similar bile-acid concentrations in gallbladders with or without AQP1, with no clear replacement of AQP1’s function by AQP8. That result conflicted with earlier work linking lower levels of AQP1 or AQP8 with weaker gallbladder concentration, so more targeted work is needed.

A clearer warning sign appears in gallstone research: lower AQP1 and AQP8 expression in the gallbladder was associated with reduced concentrating ability during cholesterol gallstone formation. In mice with reduced AQP8, gallstones formed faster, but that problem was rescued when AQP8 or AQP1 was expressed in the liver.

A small molecule called scutellarin increased AQP8 expression in liver cells and animals. In mice with AQP8, it increased bile formation, lowered bile lipid concentrations, and prevented gallstones compared with mice lacking AQP8.

Bile flow depends on water moving through liver cells, bile ducts, and the gallbladder lining. The picture matters because adjusting two water channels could change bile volume and movement, potentially easing bile blockage and reducing the risk of gallstones.

Cell and animal studies have found that natural and synthetic compounds can change aquaporins in different disease models. This raises the possibility of targeting AQP1 and AQP8 in the liver, bile ducts, and gallbladder. Changing bile concentration could be especially useful in conditions marked by poor bile flow, and in people at high risk of gallstones.

The proposed goal is practical: improve bile flow, possibly reduce symptoms and local inflammation, and regulate bile volume by changing water movement. The evidence connects aquaporins with the balance of bile composition and flow, water secretion and reabsorption, and other liver processes.

Disrupted aquaporin expression or function is associated with several bile-system disorders, including blocked bile flow diseases and cancer. Yet proposed aquaporin treatments still lack clinical trials, and many difficulties remain.

The idea is promising, but it has not reached proven patient care. In the hepatobiliary system, the body’s own aquaporins help maintain the delicate balance of bile composition and flow through bile-water secretion and reabsorption. That makes aquaporin inhibitors or modulators a possible treatment approach, although clinical trials are still lacking and many difficulties remain.

Aquaporins help balance water movement through the liver, bile ducts, and gallbladder. The findings connect disrupted water control with bile disorders and suggest possible treatments, although human trials are still missing.