A new treatment that involves targeting blood and lymphatic vessels inside the kidneys has improved renal function and slowed the progression of polycystic kidney disease in mice, according to a study published in the Journal of the American Society of Nephrology.

Treatment for polycystic kidney disease has traditionally targeted proteins that are thought to play a role in causing the condition and are located in hair-like structures and tissue that line the inside of cysts. These treatments can help alleviate some of the symptoms of PKD but they can't cure the condition.

Researchers have now discovered that the blood and lymphatic system surrounding cysts may also be important in the development of the condition and could be a new target for treating the disease.

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"If we could target these blood vessels early in the development of the condition it could potentially lead to much better outcomes for patients," said Adrian Woolf, Professor of Paediatric Science at the University of Manchester and co-author of the study.

By looking at mouse models of both the common and rarer form of the disease, the team noticed that tiny blood vessels surrounding the cysts were altered very early in cyst development. They treated the mice with a potent 'growth factor' protein called VEGFC, and found that patterns of blood vessels normalized and the function of the kidneys improved. In the mice with the rare form of the condition, it also led to a modest but significant increase in lifespan.

 "With further testing, treatments that target blood vessels surrounding the kidney cysts, perhaps in combination with currently used drugs, may prove to be beneficial for patients with polycystic kidney disease," said David Long, lead researcher and Principal Research Associate at the ICH.