IL1B and nephrocalcinosis: To identify earlier changes that might have occurred before tubulointerstitial fibrosis and nephrocalcinosis became evident at the histological level, we evaluated renal expression of several markers for renal tubular damage (Osteopontin, Ngal, and Kim‐1) and inflammation (Mcp‐1, Tnf‐α, IL‐1β, Tgf‐β1, and IL‐36α) at 10 days after increasing phosphate excretion per nephron (Fig. 2).