CLDN5 and brain ischemia: Tsoi et al. showed that AGNHW exerted neuroprotective effects and minimized cerebral ischemia–reperfusion injury e.g. alleviated oxidative and nitrative (peroxynitrite) stress-mediated matrix metalloproteinase activation and protecting tight junction proteins ZO-1 and claudin-5, which are important components in maintaining the blood-brain barrier.