The Northeastern Section of the American Urological Association, Inc.

Kidney stones affect nearly 10% of the population and its prevalence has risen dramatically over the past twenty years2. As a result, urolithiasis represents a tremendous burden on the health care system that can be reduced with an increased understanding of the causal factors. The majority of stones are calcium in nature suggesting that urolithiasis could have ties to other diseases of aberrant calcification such as vascular calcification. Microbially-derived menaquinones (vitamin K2) have been shown to mitigate calcification via the activation of Gla protein. Thus, our study sets out to understand how microbial products from the gut microbiome could influence calcium stone disease. Using an observational clinical trial, we will investigate how makers of calcification differ between stone formers and controls. We will also relate levels of circulating menaquinone to the composition of the microbiota. We also plan to develop an in vitro spheroid cell model of calcification where we can test the ability of microbially-derived menaquinones to reduce crystal formation. Together this research will build links between disease of calcification and kidney stone disease. Competition of this study will result in a better understanding of how the gut microbiome can influence urolithiasis. Additionally, we will develop a new model of stone disease that can be used to test the ability of substances to mediate crystal formation.