Do organic substances act as a degradable binding matrix in calcium oxalate kidney stones?

Calcium oxalate (CaOx) stones are considered to be highly resistant to chemolysis. While significant organic matter has been identified within these stones, which is presumed to bind (inorganic) CaOx particles and aggregates, most chemolysis efforts have focused on methods to attack the CaOx components of a stone. We examine the feasibility of inducing chemolysis of CaOx kidney stones, within hours, by specifically attacking the organic matrix present in these stones.

In contrast to previous studies, we focused on the possible "brick and mortar" stone configuration. We systematically tested, via in vitro experiments, the ability of an extensive range of 26 potential chemolysis agents to induce relatively fast disintegration (and/or dissolution) of a large set of natural CaOx stone fragments, extracted during endourological procedures, without regard to immediate clinical application. Each stone fragment was monitored for reduction in weight and other changes over 72 h.

We find that agents known to attack organic material have little, if any, effect on stone chemolysis. Similarly, protein and enzymatic agents, and oral additive medical treatments, have little immediate effect.

These findings suggest that the organic and inorganic constituents present in CaOx stones are not structured as "brick and mortar" configurations in terms of inorganic and organic components.