Pathophysiology of Uric Acid Nephrolithiasis

This study has two aims: Aim 1: To determine the presence of accumulation of fat within cells and the functional consequences of this in the kidney by correlating kidney fat content with urine test results. Aim 2: The investigators will evaluate the effect of thiazolidinedione (pioglitazone) on excess fatty acid accumulation in kidney tissue and its correlation with uric acid stone formation in subjects with uric acid stones. Pioglitazone is already U.S. Food \& Drug Administration (FDA)-approved for the treatment of type 2 diabetes, but is not approved by the FDA for treating or preventing or diagnosing stone risk.