Journal Article

Quantitative analysis of calcium oxalate monohydrate and dihydrate for elucidating the formation mechanism of calcium oxalate kidney stones

Okada, Atsushi, Yasui, Takahiro, Ando, Ryosuke, Tsukamoto, Katsuo, Nakamura, Masanori, Taguchi, Kazumi, Sawada, Koichi P., Mori, Ryota, Tajiri, Rie, Hamamoto, Shuzo, Sugiura, Yuki, Momma, Koichi, Furukawa, Yoshihiro, Tanaka, Yutaro, Mori, Yusuke, Imanishi, Masayuki, Maruyama, Mihoko, Takano, Kazufumi, Yoshimura, Masashi

2023

Overview

We sought to identify and quantitatively analyze calcium oxalate (CaOx) kidney stones on the order of micrometers, with a focus on the quantitative identification of calcium oxalate monohydrate (COM) and dihydrate (COD). We performed Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), and microfocus X-ray computed tomography measurements (microfocus X-ray CT) and compared their results. An extended analysis of the FTIR spectrum focusing on the 780 cm −1 peak made it possible to achieve a reliable analysis of the COM/COD ratio. We succeeded in the quantitative analysis of COM/COD in 50-μm 2 areas by applying microscopic FTIR for thin sections of kidney stones, and by applying microfocus X-ray CT system for bulk samples. The analysis results based on the PXRD measurements with micro-sampling, the microscopic FTIR analysis of thin sections, and the microfocus X-ray CT system observation of a bulk kidney stone sample showed roughly consistent results, indicating that all three methods can be used complementarily. This quantitative analysis method evaluates the detailed CaOx composition on the preserved stone surface and provides information on the stone formation processes. This information clarifies where and which crystal phase nucleates, how the crystals grow, and how the transition from the metastable phase to the stable phase proceeds. The phase transition affects the growth rate and hardness of kidney stones and thus provides crucial clues to the kidney stone formation process.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Biology and Life Sciences / Bulk sampling / Calcium / Calcium oxalate / Calcium Oxalate - chemistry / Calculi / Care and treatment / Comparative analysis / Computed tomography / Crystal growth / Crystals / Diffraction / Fourier transforms / Growth rate / Health aspects / Humans / Information processing / Infrared spectroscopy / Kidney Calculi - chemistry / Kidney Calculi - diagnostic imaging / Kidney stones / Kidneys / Lithotripsy / Medicine and Health Sciences / Metastable phases / Micrometers / Microscopy / Nephrolithiasis / Oxalates / Oxalic acid / Pathogenesis / Patient outcomes / Phase transitions / Physical Sciences / Proteins / Quantitative analysis / Research and Analysis Methods / Spectroscopy / Spectroscopy, Fourier Transform Infrared / Tomography, X-Ray Computed / X ray powder diffraction / X-ray diffraction / X-Rays