Fig. 3.

Hypothetical interactions of supersaturated and nonsupersaturated tubular fluid and crystals with the renal tubular epithelium and/or urinary extracellular vesicles (EVs) in normal physiological (A) and pathological (B) conditions. Crystal attachment to the renal tubular epithelium in nonsupersaturated (physiological) conditions is low and the excreted number of urinary EVs is greater, whereas crystal attachment to the tubular epithelium in supersaturated (pathological) conditions is significantly greater and the number of urinary EVs is significantly lower. The resulting interstitial accumulation of crystals is greater in stone formers compared with non-stone formers. CaOx, calcium oxalate.