RESUMO
BACKGROUND: With therapeutic hypothermia (HT) for neonatal encephalopathy, disability rates are reduced, but not all babies benefit. Pre-clinical rodent studies suggest mesenchymal stromal cells (MSCs) augment HT protection. AIMS: The authors studied the efficacy of intravenous (IV) or intranasal (IN) human umbilical cord-derived MSCs (huMSCs) as adjunct therapy to HT in a piglet model. METHODS: A total of 17 newborn piglets underwent transient cerebral hypoxia-ischemia (HI) and were then randomized to (i) HT at 33.5°C 1-13 h after HI (n = 7), (ii) HT+IV huMSCs (30 × 106 cells) at 24 h and 48 h after HI (n = 5) or (iii) HT+IN huMSCs (30 × 106 cells) at 24 h and 48 h after HI (n = 5). Phosphorus-31 and hydrogen-1 magnetic resonance spectroscopy (MRS) was performed at 30 h and 72 h and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells and oligodendrocytes quantified. In two further piglets, 30 × 106 IN PKH-labeled huMSCs were administered. RESULTS: HI severity was similar between groups. Amplitude-integrated electroencephalogram (aEEG) recovery was more rapid for HT+IN huMSCs compared with HT from 25 h to 42 h and 49 h to 54 h (P ≤ 0.05). MRS phosphocreatine/inorganic phosphate was higher on day 2 in HT+IN huMSCs than HT (P = 0.035). Comparing HT+IN huMSCs with HT and HT+IV huMSCs, there were increased OLIG2 counts in hippocampus (P = 0.011 and 0.018, respectively), internal capsule (P = 0.013 and 0.037, respectively) and periventricular white matter (P = 0.15 for IN versus IV huMSCs). Reduced TUNEL-positive cells were seen in internal capsule with HT+IN huMSCs versus HT (P = 0.05). PKH-labeled huMSCs were detected in the brain 12 h after IN administration. CONCLUSIONS: After global HI, compared with HT alone, the authors saw beneficial effects of HT+IN huMSCs administered at 24 h and 48 h (30 × 106 cells/kg total dose) based on more rapid aEEG recovery, improved 31P MRS brain energy metabolism and increased oligodendrocyte survival at 72 h.