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The following is a summary of “Post-ESWL urinary osteopontin level and ion-activity product of calcium oxalate are associated with stone recurrence after 5-year follow-up,” published in the April 2025 issue of BMC Urology by Liu et al. 

Calcium oxalate (CaOx) makes up over 80% of kidney stones. Its formation involves multiple mechanisms, including interactions with renal tubular cells and Randall’s plaques. 

Researchers conducted a retrospective study to examine changes in CaOx-related proteins before and after extracorporeal shock wave lithotripsy (ESWL), identifying markers linked to stone recurrence over a 5-year follow-up. 

They enrolled 54 patients with renal or ureteral stones treated with ESWL and 13 healthy controls. 24-hour urine samples were collected preoperatively and at 2 and 4 weeks post-ESWL for biochemical analysis. CaOx-related proteins, including nucleolin-related protein (NRP), nuclear pore complex p62 (NPC), hyaluronic acid (HA), SLC26A6, CXCR4, osteopontin (OPN), tamm-horsfall protein (THP) and matrix metalloproteinase (MMPs), were measured semi-quantitatively. Statistical analyses, including Pearson correlation and logistic regression, were used to identify factors related to 5-year stone recurrence, with statistical significance set at P < 0.05. 

The results showed that before ESWL, stone patients had significantly higher levels of NPC, HA, and CXCR4. All markers, except Tamm-Horsfall protein, increased significantly at 2 weeks post-ESWL. At 4 weeks, OPN and SLC26A6 remained higher. Correlations were found between CXCR4, MMPs, stone size, and AP_CaOX. Logistic regression identified urinary OPN and AP_CaOX at 4 weeks as significant factors influencing 5-year stone recurrence, with a recurrence rate of 48.4%. 

Investigators found that the persistence of certain urinary proteins after ESWL indicated a risk of stone recurrence. Stone recurrence at 5 years was significantly associated with higher urinary OPN and AP_CaOX levels at 4 weeks post-ESWL. 

Source: bmcurol.biomedcentral.com/articles/10.1186/s12894-025-01791-x