The elementome of calcium-based urinary stones and its role in urolithiasis

The elementome—the full spectrum of elemental content—of urinary calculi is emerging as a new concept in stone research. Here, Ramaswamy et al. summarize current knowledge of the elementome of calcium-based urinary calculi and highlight study results of clinical relevance that could be shaping future therapeutic strategies in urolithiasis. Urolithiasis affects around 10% of the US population with an increasing rate of prevalence, recurrence and penetrance. The causes for the formation of most urinary calculi remain poorly understood, but obtaining the chemical composition of these stones might help identify key aspects of this process and new targets for treatment. The majority of urinary stones are composed of calcium that is complexed in a crystalline matrix with organic and inorganic components. Surprisingly, mitigation of urolithiasis risk by altering calcium homeostasis has not been very effective. Thus, studies to identify other therapeutic stone-specific targets, using proteomics, metabolomics and microscopy techniques, have been conducted, revealing a high level of complexity. The data suggest that numerous metals other than calcium and many nonmetals are present within calculi at measurable levels and several have distinct distribution patterns. Manipulation of the levels of some of these elemental components of calcium-based stones has resulted in clinically beneficial changes in stone chemistry and rate of stone formation. The elementome—the full spectrum of elemental content—of calcium-based urinary calculi is emerging as a new concept in stone research that continues to provide important insights for improved understanding and prevention of urinary stone disease.