OCLN and myeloid sarcoma: After the administration of spermidine in mice with EAE, this polyamine suppressed disease progression by inhibiting MF activity.73 Luminal putrescine is important for colonocyte proliferation and maintenance of gut mucosal homeostasis,74 which could be in line with our results that both MDSC and MDSC-PGE2 applications increased claudin and occludin expression, thus potentially providing increased protection of the intestinal barrier from systemic inflammation in EAE and MS.