SPP1 and Stroke: Osteopontin (OPN), a secreted extracellular matrix protein, acts as a potent soft tissue mineral inhibitor resulting in of inhibiting soft tissue mineralization, delaying and preventing ectopic calcification of the vasculature.3 Existing studies have shown that OPN can protect nerves after brain injury.4 OPN is also a cytokine involved in the inflammatory response, which intensifies the inflammatory response.5 However, few studies have been conducted on the role of OPN in stroke in humans.