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  3. Novel Methods of Determining Urinary Calculi Composition: Petrographic Thin Sectioning of Calculi and Nanoscale Flow Cytometry Urinalysis

Novel Methods of Determining Urinary Calculi Composition: Petrographic Thin Sectioning of Calculi and Nanoscale Flow Cytometry Urinalysis

  • Sci Rep. 2016 Jan 14:6:19328. doi: 10.1038/srep19328.
Carson T Gavin 1 2,  Sohrab N Ali 1 2,  Thomas Tailly 1,  Daniel Olvera-Posada 1,  Husain Alenezi 1,  Nicholas E Power 1,  Jinqiang Hou 3,  Andre H St Amant 3,  Leonard G Luyt 3,  Stephen Wood 4,  Charles Wu 4,  Hassan Razvi 1,  Hon S Leong 1 2
Affiliations

Affiliations

  • 1 Department of Surgery, Division of Urology, Department of Surgery, Western University, London, Ontario, Canada.
  • 2 Translational Prostate Cancer Research Laboratory, Lawson Health Research Institute, London, Ontario, Canada.
  • 3 Department of Chemistry, Western University, London, Ontario, Canada.
  • 4 Department of Earth Sciences, Western University, London, Ontario, Canada.
PMID: 26771074 DOI: 10.1038/srep19328
Abstract

Accurate determination of urinary stone composition has significant bearing on understanding pathophysiology, choosing treatment modalities and preventing recurrence. A need exists for improved methods to determine stone composition. Urine of 31 patients with known renal calculi was examined with nanoscale flow cytometry and the calculi collected during surgery subsequently underwent petrographic thin sectioning with polarized and fluorescent microscopy. Fluorescently labeled bisphosphonate probes (Alendronate-fluorescein/Alendronate-Cy5) were developed for nanoscale flow cytometry to enumerate nanocrystals that bound the fluorescent probes. Petrographic sections of stones were also imaged by fluorescent and polarized LIGHT microscopy with composition analysis correlated to alendronate +ve nanocrystal counts in corresponding urine samples. Urine samples from patients with Ca(2+) and Mg(2+) based calculi exhibited the highest alendronate +ve nanocrystal counts, ranging from 100-1000 nm in diameter. This novel urine based assay was in agreement with composition determined by petrographic thin sections with Alendronate probes. In some cases, high alendronate +ve nanocrystal counts indicated a Ca(2+) or Mg(2+) composition, as confirmed by petrographic analysis, overturning initial spectrophotometric diagnosis of stone composition. The combination of nanoscale flow cytometry and petrographic thin sections offer an alternative means for determining stone composition. Nanoscale flow cytometry of alendronate +ve nanocrystals alone may provide a high-throughput means of evaluating stone burden.

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