GDNF secreted from peripheral nerve pericytes has been found to be one of the key molecules responsible for upregulation of claudin-5 expression in the BNB (Shimizu et al., 2012) indicating that regulation of trophic factor secretion from pericytes may modify BNB functions, potentially facilitating axonal regeneration and remyelination in DN. Here, GDNF is linked to liver dysplastic nodule.