SPP1 and renal fibrosis: Previous studies have demonstrated that MI can induce renal fibrosis, with a concurrent decline in glomerular filtration rate as early as three days post-MI.40 This functional impairment was further reflected by elevated serum creatinine and blood urea nitrogen levels, indicating progressive renal dysfunction.40 Nevertheless, POSTN and SPP1/OPN are pleiotropic molecules with known systemic actions affecting multiple organs and therefore inferred signalling axis is probably not restricted to the heart-kidney interaction.