Destruction of the protein matrix of kidney stones by solutions of non-toxic complexons with surfactant properties

Aim. To investigate the effects of solutions composed of molecules with both chelating and surfactant properties on kidney stones.

Materials and Methods. Kidney stones and their fragments were obtained during ureteroscopy and retrograde intrarenal surgery, percutaneous nephrolithotomy, and stone extraction from the kidney performed in patients with urolithiasis. For the experiment, a solution was prepared based on a composition of iminodiacetate derivatives of fatty acid glycerides and iminodiacetate derivatives of polysaccharides. Stones of known mass were processed with this solution, dried, and examined using X-ray diffraction analysis. Qualitative protein analysis (biuret test) was performed on the solution and washout fluid.

Results. Struvite stones (MgNH₄PO₄(H₂O)₆) swelled in the solution and disintegrated into small fragments. Proteins and phosphate ions were detected in the prepared solution. Stones composed of crystalline uric acid or its hydrate, as well as hydrated calcium oxalates (whewellite and weddellite), also swelled, with occasional changes in surface structure and color. X-ray diffraction analysis revealed a decrease in the amorphous, presumably protein, component and changes in the relative proportions of crystallohydrates. The presumed mechanism of stone destruction was leaching of the amorphous protein binder between crystalline grains, together with alterations in the crystalline phases.

Conclusion. Complexons with emulsifying properties from the prepared solution penetrate the protein matrix of kidney stones and, together with enhanced water diffusion, cause partial protein extraction, swelling of amorphous and some crystalline phases, and subsequent stone disintegration. These findings highlight the potential of such hybrid compounds for the development of novel methods of treating urolithiasis and warrant further investigation.