Comparison of cat stone matrix and cat urine proteomes to human calcium oxalate stone matrix and urine proteomes

Cat calcium oxalate monohydrate kidney stone matrix proteome showed great similarity to human calcium oxalate monohydrate stone matrix proteome, but inference of mechanistic similarity was limited by the absence of cat urine proteomic data. In this study, urine proteome distributions were measured by the same methods in 7 healthy cats for comparison to both the published human urine and cat calcium oxalate stone matrix proteomes to assess for similar enrichment patterns in both species. Furthermore, proteomic distributions were determined in cat struvite stone matrix to test for similarity to calcium oxalate monohydrate stone matrix and urine proteomes. Cat urine proteins demonstrated a similar distribution of abundance as a function of isoelectric points or net charge to human urine samples, and consequently the similarly altered patterns of protein distributions seen in calcium oxalate monohydrate stone matrix seen from both cat and human stones likely derives from the same preferential adsorption mechanism. Furthermore, the fact that protein abundance patterns seen in cat struvite stone matrix samples differ from both urine and calcium oxalate monohydrate stone matrix proteomes in systematic ways suggests that a combination of protein–protein and protein crystal interactions underly the formation of the crystal aggregates that comprise stones.