The neurorestorative effect of human amniotic fluid stem cells on the chronic phase of neonatal hypoxic-ischemic encephalopathy in mice

BACKGROUND: Hypoxic-ischemic encephalopathy (HE) remains a major cause of cerebral palsy. Increasing evidence has suggested that mesenchymal stem cells have a favorable effect on HIE. However, the efficacy of human amniotic fluid stem cells (hAFS) for HE, especially in the chronic phase, remains unclear. The aim of this study was to determine the neurorestorative effect of hAFS on the chronic phase of HIE. METHODS: hAFS were isolated from AF cells as CD117-positive cells. HI was induced in 9-day-old mice. Animals intranasally received hAFS or phosphate-buffered saline at 10 days post HI and were harvested for histological analysis after functional tests at 21 days post HI. We also implanted PKH26-positive hAFS to assess their migration to the brain. Finally, we determined gene expressions of trophic factors in hAFS co-cultured with HI brain extract. RESULTS: hAFS improved sensorimotor deficits in HIE by gray and white matter restoration and neuroinflammation reduction followed by migration to the lesion. Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), hepatocyte growth factor (HGF), and stromal cell-derived factor-1 (SDF-1) gene expressions in hAFS were elevated when exposed to HI-induced brain extract. CONCLUSION: hAFS induced functional recovery by exerting neurorestorative effects in HIE mice, suggesting that intranasal administration of hAFS could be a novel treatment for HIE, especially in the chronic phase.