KIDNEY STONES, MINERAL CRUSTS, AND PLANTS: WHAT CAN WE LEARN ABOUT KIDNEY STONES FROM THE NATURAL ENVIRONMENT?

Kidney stones affect approximately 10-20% of the world population and can cause many health problems including severe pain, blocked urine flow, and renal failure. The most common types of kidney stones, whewellite (CaC₂O₄^.H₂O) and weddellite (CaC₂O₄.2H₂O), are calcium oxalate minerals which form by the aggregation of supersaturated calcium oxalate crystals in the kidneys. Outside of the human body, calcium oxalate forms commonly in plants and has been found frequently as crusts on rock surfaces. In this presentation, we will examine previous research on kidney stone synthesis in a laboratory and compare the findings with natural examples of whewellite and weddellite formation on rock surfaces and within plants.

In this study, kidney stones were synthesized in synthetic urine solutions at various pH values, salt concentrations, and organic urinary component concentrations to understand the effects of these factors on kidney stone formation. The synthesized calcium oxalate crystals were then analyzed with x-ray diffraction and optical microscopy to identify mineralogy, crystal shapes, and growth behavior. In line with previous research that indicated that the chemistry, temperature, and pH of the urine play a major role in stone formation, our research also indicates that the organic urinary molecules present play a role in the formation, mineralogy, and morphology of the microcrystals. We also consider recent literature findings about in vivo partial dissolution of kidney stone minerals during their formation process, biofilm attachment behavior, and the factors that play a role in kidney stone morphology. The results from these human-stone studies are compared with published literature on the morphology and biomineralization of whewellite and weddellite in plants and the formation of mineral crusts on rocks. The comparison reveals that the mineral formation processes, such as dissolution, precipitation, and paragenetic sequences, occurring outside of the body can inform the understanding of kidney stone formation development inside the human body. This understanding may shed light on their formation inside the human body, which can aid in the development of treatment and prevention strategies to combat these debilitating minerals.