Ultrastructure and pathogenesis of human urinary calculi

Area of Science:

• Biomineralization research
• Urology
• Materials science

Background:

• Human urinary calculi (stones) are complex biomineralizations.
• Understanding stone ultrastructure is crucial for diagnosis and treatment.
• Hydroxyapatite is a common component of urinary stones.

Purpose of the Study:

• To investigate the ultrastructure of human urinary calculi.
• To characterize the morphology of hydroxyapatite deposits in urinary stones.
• To compare these structures with calcified tissues in other conditions.

Main Methods:

• Scanning electron microscopy (SEM) of urinary calculi.
• Transmission electron microscopy (TEM) of urinary calculi.
• Analysis of hydroxyapatite crystallite aggregation and lamellar formation.

Main Results:

• Urinary calculi often contain spherical aggregates of hydroxyapatite crystallites (1-10 μm).
• These spherical deposits exhibit concentric lamellar structures.
• This morphology is similar to structures found in nephrocalcinosis and malakoplakia.

Conclusions:

• Spherical, lamellar hydroxyapatite deposits represent a distinct ultrastructural feature of human urinary calculi.
• These findings provide new insights into the formation mechanisms of urinary stones.
• The similarity to other calcified tissues suggests shared biomineralization pathways.