POLDIP2 and brain ischemia: In the present study, we found an increase in both MMP-2 and MMP-9 mRNA and a clear increase in MMP-9 activity in Poldip-2+/+ mice but not in Poldip2+/− mice, implying that reduction in MMP activity may contribute to the reduced BBB permeability in Poldip2+/− mice after cerebral ischemia [50].