Zinc-enriched Pathological Biominerals in the Human Kidney Encode their Anatomical Microenvironments

Area of Science:

• Biomineralization
• Renal physiology
• Materials science

Background:

• Kidney stone formation mechanisms are poorly understood, leading to high recurrence.
• Stones are traditionally viewed as uniform mineral deposits from urine supersaturation.
• Existing paradigms do not fully explain stone heterogeneity across renal microenvironments.

Purpose of the Study:

• To investigate if kidney stones preserve physicochemical signatures of their anatomical origin.
• To determine if zinc (Zn) organization reflects microenvironment-specific mineralization processes.
• To challenge the traditional view of kidney stones as monolithic structures.

Main Methods:

• Utilized a multiscale correlative microspectroscopy workflow.
• Characterized three morphologically distinct biominerals from three distinct renal niches.
• Analyzed spatial gradients of zinc, calcium, phosphorus, and organic matrix components.

Main Results:

• Distinct renal microenvironments yield anatomy-specific biominerals (papillary vs. collecting system).
• Zinc is a spatially organized constituent, enriched in papillary regions and colocalizing with phosphorus.
• Identified conserved calcium and phosphorus nanoparticles, suggesting shared nucleation units.
• Proposed a hierarchical mineralization model involving Zn-associated domains.

Conclusions:

• Kidney stones are heterogeneous, anatomy-specific biominerals encoding microenvironment signatures.
• Zinc plays a key role in early mineralization, not just as a trace element.
• Findings support complementary mechanisms of stone formation (intratubular and interstitial).
• Targeting localized renal microenvironments is crucial for improved therapeutic interventions.