Researchers at the Mayo Clinic have uncovered a new way the kidneys keep the body’s water levels steady. This finding could lead to better care for people with polycystic kidney disease (PKD) and other kidney problems.
Kidney Controls Water Without Hormone
Doctors used to think a hormone called vasopressin was the main player in concentrating urine and preventing dehydration. The new study shows that kidneys have another, separate route that works without this hormone.
Why This Matters for PKD
PKD is a genetic illness that creates fluid‑filled cysts in the kidneys. Over time, these cysts can damage kidney function and may cause kidney failure. In the United States, about 140,000 people have the most common form, called autosomal dominant PKD.
An Old Drug Gives a Surprising Result
While testing drugs on lab‑grown kidney cells, Dr. Chebib’s team tried a medicine called probenecid. This drug was first used in the 1940s to keep more penicillin in the body. The scientists expected it to make cysts grow faster, but the opposite happened.
Probenecid actually slowed cyst growth. Repeating the experiment gave the same outcome each time, so the researchers realized they had stumbled onto something new.
Urate Helps Kidneys Keep Water
Further tests showed that probenecid changes how kidney cells handle a molecule called urate. Inside the cells, urate acts like a signal that moves water channels to the cell surface. This lets the kidney pull water back into the body and make urine more concentrated—without needing vasopressin.
"This is a separate water‑saving route that we didn’t know existed," Dr. Chebib explained.
Potential Boost for Existing PKD Treatment
The only drug approved to slow PKD is tolvaptan, which blocks vasopressin. While it helps, it also forces patients to urinate large amounts—often 6‑7 liters a day—making life difficult.
In early studies, adding probenecid lowered the amount of urine people produced by about 30 %. Many patients went from waking up several times at night to only once. They also reported feeling better overall.
Looking Ahead
Even though probenecid showed promise, it is an old drug that affects many parts of the body and is not widely used today. The research team hopes to design new medicines that target the newly discovered water‑saving pathway directly.
"Probenecid gave us a clue, but we want to build a treatment that hits this pathway specifically," Dr. Chebib said.
A Personal Drive
Dr. Chebib’s interest in kidney disease began when his father was diagnosed with PKD. That personal connection fuels his dedication to finding better solutions for patients.