Polycystic kidney disease (PKD) is a genetic disease that occurs in 1 in 500 individuals and leads to kidney failure in half of all affected. Currently, no treatments exist for PKD. PKD-affected kidney cells divide and multiply inappropriately, and form fluid-filled sacs called cysts. Kidney cysts continue to grow throughout life, destroying normal kidney tissue, leading to kidney failure. Based on evidence from basic science research it is believed that drinking high amounts of water can slow the abnormal cysts growth. This study aims to look at changes in urine composition with high water intake in PKD-affected persons compared to healthy individuals.

Inclusion Criteria:

• Clinical diagnosis of Autosomal Dominant Polycystic Kidney Disease by history, ultrasound, CT or MRI
• Healthy subjects without a diagnosis of Polycystic Kidney Disease by history, ultrasound, CT or MRI
• Ages between 18 and 65
• Healthy subjects (without Polycystic Kidney Disease) must have an estimated glomerular filtration rate (eGFR by the MDRD equation) > 60 ml/min/1.73 m2 with no history of kidney disease

Exclusion Criteria:

• Women who are pregnant or nursing
• Active dependency on drugs or alcohol
• Diagnosis of syndrome of inappropriate antidiuresis
• Currently taking a vasopressin agonist or antagonist
• Blood sodium level less than < 135 mEq/L
• For healthy participants, estimated glomerular filtration rate (level of kidney function) less than < 60 ml/min/1.73 m2

This was a very small study, so larger numbers are needed. Urine cAMP measurement as a surrogate of response to water treatment needs further validation.