This prospective observational case-control study aims to evaluate the presence and burden of microplastic particles in urine samples from patients with kidney and ureteral stones and to compare these findings with healthy controls. The study will also investigate the associations between urinary microplastic burden and clinical characteristics of urinary stone disease, including stone size, stone density measured in Hounsfield units (HU), localization, and stone composition.
Urinary stone disease is a common urological condition with a multifactorial etiology. Although established metabolic, dietary, genetic, and environmental factors contribute to stone formation, the potential role of microplastic exposure in urinary stone disease remains insufficiently understood. In this prospective observational case-control study, patients diagnosed with kidney or ureteral stones and healthy control participants will be evaluated. Following informed consent, demographic and clinical data will be collected. A midstream urine sample will be obtained from each participant for laboratory analysis. Urine samples will undergo laboratory processing for the detection and characterization of suspected microplastic particles. The analytical process will include centrifugation, Proteinase K treatment, membrane filtration, microscopic examination, image analysis using ImageJ, and Fourier-transform infrared (FTIR) spectroscopy for polymer identification. In participants with urinary stones, available stone specimens will also be analyzed for stone composition. Imaging-derived stone characteristics, including stone size, localization, and density in Hounsfield units, will be recorded. The primary objective is to compare urinary microplastic burden between participants with urinary stones and healthy controls. Secondary analyses will investigate the relationships between urinary microplastic burden and stone characteristics, including stone size, density, localization, and composition. The study does not involve administration of investigational drugs, use of investigational medical devices, or additional invasive procedures. Participation will involve collection of a urine sample and collection of clinical data obtained during routine clinical care.
Study Type
OBSERVATIONAL
Enrollment
100
This is an observational study. No study-specific intervention will be assigned to participants.
Urinary Microplastic Burden
Urinary microplastic burden will be assessed as the number of confirmed microplastic particles detected per milliliter of urine (particles/mL). Microplastic particles will be identified by microscopic examination and confirmed by FTIR spectroscopy based on polymer characteristics. The urinary microplastic burden will be compared between the urinary stone group and the healthy control group.
Time frame: At enrollment
Microplastic Polymer Type
The polymer types of confirmed microplastic particles detected in urine samples will be identified by FTIR spectroscopy and reported according to polymer type, including polyethylene, polypropylene, polyethylene terephthalate, polystyrene, and other identified polymers.
Time frame: At enrollment
Association Between Urinary Microplastic Burden and Stone Size
The association between urinary microplastic burden and maximum urinary stone diameter will be evaluated in participants with kidney or ureteral stones.
Time frame: At enrollment
Association Between Urinary Microplastic Burden and Stone Density
The association between urinary microplastic burden and urinary stone density measured in Hounsfield units (HU) on computed tomography will be evaluated in participants with kidney or ureteral stones.
Time frame: At enrollment
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