Abstract
Purpose :
ST266 is the biological secretome of Amnion-derived Multipotent Progenitor (AMP) cells. ST266 proteins accumulate in eyes and optic nerves following intranasal delivery, resulting in selective suppression of optic neuritis in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis, without suppressing spinal cord lesions. We tested the hypothesis that systemic AMP cell administration could suppress both optic neuritis and myelitis in EAE.
Methods :
C57/BL6 EAE mice, induced by immunization with myelin oligodendroglial glycoprotein peptide, were administered 2x106 AMP cells, or were sham-injected, by either intravenous or intraperitoneal injection on day 9 after EAE induction. Additional mice received repeated administrations of 1x106 AMP cells on days 9, 12, and 15. Spinal cord dysfunction was assessed by daily scoring of EAE-induced ascending paralysis, and visual function was assessed by optokinetic responses weekly until sacrifice 6 weeks post-immunization. Retinal ganglion cells (RGCs) were immunolabeled with Brn3a antibodies and counted. Inflammation was assessed by H&E and Iba1 staining, and demyelination by luxol fast blue staining, of spinal cord and optic nerve sections.
Results :
Single high-dose intravenous and intraperitoneal, and repeated low-dose intravenous, administration of AMP cells significantly reduced ascending paralysis in EAE mice (p<0.001). Repeated low-dose intravenous and intraperitoneal AMP cell administration significantly attenuated visual dysfunction in EAE mice (p<0.05). All four AMP cell treatment cohorts demonstrated increased RGC survival (p<0.05) and decreased optic nerve inflammation (p<0.05) as compared with sham-treated EAE mice, and AMP cells induced variable levels of improvement in optic nerve demyelination and spinal cord inflammation and demyelination.
Conclusions :
Systemic AMP cell administration inhibits RGC loss and reduces visual dysfunction induced by EAE optic neuritis, similar to previously demonstrated effects of intranasally-delivered ST266. Importantly, AMP cells also promote neuroprotective effects in EAE spinal cords, marked by reduced paralysis. Further investigation of AMP cells as a potential therapy for inflammatory demyelinating disease is warranted.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.