Macromolecules and urolithiasis: parallels and paradoxes

Long-standing interest in the possible role of macromolecules in urolithiasis stems from the observation that all human kidney stones consist of a complex amalgam of mineral and organic material. This review summarises what is currently known or is hypothesised about the influences of urinary macromolecules, especially proteins, on the formation of calcium oxalate crystals, their attachment to renal epithelial cells, and their subsequent destruction within those cells. Although a list is provided of proteins that have either been detected in stones or have been implicated by virtue of their effects on crystallization, only a select handful, which have been intensively studied, have been singled out for individual discussion. The review ends with a speculative discussion of the applicability of current knowledge to the investigation and treatment of urolithiasis.