The impact of crystal phase transition on the hardness and structure of kidney stones

• Published in: Urolithiasis Vol. 52; no. 1; p. 57
• Main Authors: Michibata, Uta, Maruyama, Mihoko, Tanaka, Yutaro, Yoshimura, Masashi, Yoshikawa, Hiroshi Y., Takano, Kazufumi, Furukawa, Yoshihiro, Momma, Koichi, Tajiri, Rie, Taguchi, Kazumi, Hamamoto, Shuzo, Okada, Atsushi, Kohri, Kenjiro, Yasui, Takahiro, Usami, Shigeyoshi, Imanishi, Masayuki, Mori, Yusuke
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 02.04.2024; Springer Nature B.V
• Subjects: Aggregates; Body Fluids; Calcium Oxalate; Hardness; Humans; Kidney Calculi; Kidney stones; Lithotripsy; Medical Biochemistry; Medicine; Medicine & Public Health; Nephrology; Phase transitions; Urology; Solution-mediated phase transition; X-ray micro-CT; Calcium oxalate; Microstructure; Kidney stones; Extracorporeal shock wave lithotripter
• ISSN: 2194-7236; 2194-7228; 2194-7236
• DOI: 10.1007/s00240-024-01556-5

Calcium oxalate kidney stones, the most prevalent type of kidney stones, undergo a multi-step process of crystal nucleation, growth, aggregation, and secondary transition. The secondary transition has been rather overlooked, and thus, the effects on the disease and the underlying mechanism remain unclear. Here, we show, by periodic micro-CT images of human kidney stones in an ex vivo incubation experiment, that the growth of porous aggregates of calcium oxalate dihydrate (COD) crystals triggers the hardening of the kidney stones that causes difficulty in lithotripsy of kidney stone disease in the secondary transition. This hardening was caused by the internal nucleation and growth of precise calcium oxalate monohydrate (COM) crystals from isolated urine in which the calcium oxalate concentrations decreased by the growth of COD in closed grain boundaries of COD aggregate kidney stones. Reducing the calcium oxalate concentrations in urine is regarded as a typical approach for avoiding the recurrence. However, our results revealed that the decrease of the concentrations in closed microenvironments conversely promotes the transition of the COD aggregates into hard COM aggregates. We anticipate that the suppression of the secondary transition has the potential to manage the deterioration of kidney stone disease.