We did not examine the blood-brain barrier, but changes in diabetes have been reported: Cldn5 and pericyte coverage are decreased in old diabetic mice [34] and claudin-5 forms larger gaps in brain capillaries after 8 weeks STZ-induced diabetes together with cognitive impairment [35] So, several barriers are affected in diabetes, but the role of specific tight junction proteins like claudin-5 seems to depend on anatomical location as well as duration and type of diabetes. Here, CLDN5 is linked to diabetes mellitus.