2082 STRONTIUM SUBSTITUTION FOR CALCIUM IN LITHOGENESIS

Abstract

You have accessJournal of UrologyStone Disease: Basic Research I1 Apr 20122082 STRONTIUM SUBSTITUTION FOR CALCIUM IN LITHOGENESIS Sarah D. Blaschko, MD Lawrence Flechner, MD Gyorgy Snell, PhD Thomas Chi, MD Joe Miller, MD Sirine Fakra, andMS Marshall L. StollerMD Sarah D. BlaschkoSarah D. Blaschko San Francisco, CA More articles by this author , Lawrence FlechnerLawrence Flechner San Francisco, CA More articles by this author , Gyorgy SnellGyorgy Snell Berkeley, CA More articles by this author , Thomas ChiThomas Chi San Francisco, CA More articles by this author , Joe MillerJoe Miller San Francisco, CA More articles by this author , Sirine FakraSirine Fakra Berkeley, CA More articles by this author , and Marshall L. StollerMarshall L. Stoller San Francisco, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2248AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Strontium has two available valence electrons for chemical bonding and is positioned in the same column of the periodic table as calcium. This chemical similarity enables the replacement of calcium by strontium in biological processes. Strontium has long been used as a substitute for calcium when testing calcium absorption in the gut and calcium filtration by the kidney and exists as four stable isotopes. Ratios of these isotopes have been used to identify the origins of plants, animals, and soil. Incorporation of strontium into human bone and teeth has been studied extensively, however little research has been performed on the incorporation of strontium into urinary calculi. We utilized synchrotron based X-ray fluorescence (XRF) and X-ray absorption (XAS) techniques to examine the presence of strontium in different types of human kidney stones. We postulate that the presence of strontium in urolithiasis may be utilized to help better understand early calcium-based stone pathogenesis. METHODS Multiple unique human stone samples were obtained via consecutive percutaneous nephrolithotomies/ureteroscopies and a portion was sent for standard laboratory analysis with Fourier Transform Infrared Spectroscopy (FTIR). XRF and XAS measurements were carried out at the Advanced Light Source synchrotron radiation facility at the Lawrence Berkeley National Laboratory to examine the presence, spatial distribution and speciation of strontium in each stone sample. RESULTS Traditional kidney stone analyses identified calcium oxalate, calcium phosphate, uric acid, and cystine stones. XRF measurements identified strontium in all stone types except for pure cystine. XRF elemental mapping of the samples revealed co-localization of calcium and strontium. XAS measurements of the calcium phosphate stone showed that strontium is predominately present as strontium apatite. CONCLUSIONS Advanced X-ray fluorescence methods identified strontium in all calcium based stones and is present as strontium apatite. This finding may be critical as apatite is often thought to be the initial nidus for calcium stone formation. Strontium is overlooked with standard laboratory stone analyses; substitution for calcium can be reliably identified in stones from multiple calcium-based stone formers with different stone compositions and offers insight into early events in lithogenesis. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e839 Peer Review Report Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sarah D. Blaschko San Francisco, CA More articles by this author Lawrence Flechner San Francisco, CA More articles by this author Gyorgy Snell Berkeley, CA More articles by this author Thomas Chi San Francisco, CA More articles by this author Joe Miller San Francisco, CA More articles by this author Sirine Fakra Berkeley, CA More articles by this author Marshall L. Stoller San Francisco, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...