Molecular and biochemical correlates of urinary composition in kidney stone pathogenesis

Kidney stone disease is one of the most common urological problems worldwide, with a high rate of recurrence. Even though surgical and medical treatments are available, many patients develop stones again due to underlying metabolic and biochemical abnormalities. Among the various factors involved, urinary composition plays a major role in the initiation and progression of stone formation. Changes in urinary levels of calcium, oxalate, phosphate, uric acid, and cystine increase the risk of supersaturation, which leads to crystal nucleation and growth. At the same time, reduced levels of natural inhibitors such as citrate and magnesium further promote crystal aggregation. Urinary pH also significantly influences the type of stone formed by affecting the solubility of different constituents. In addition, renal microstructural factors, including Randall's plaque formation and tubular epithelial injury, contribute to crystal retention and stone development. Understanding the correlation between urine chemistry and stone formation is essential for proper risk assessment and prevention. This review discusses the biochemical mechanisms linking urinary composition with kidney stone formation and highlights its clinical importance in improving patient management and recurrence prevention.