Neonatal stroke leads to mortality and severe morbidity, but there is no effective treatment currently available. Erythropoietin (EPO) has been shown to promote cytoprotection and neurogenesis and decrease subventricular zone morphologic changes following brain injury. The long-term cellular response to EPO has not been defined, and local changes in cell fate decision may play a role in functional improvement. We performed middle cerebral artery occlusion in P10 rats. EPO treatment (5 U/g IP) significantly preserved hemispheric brain volume 6 weeks after injury. Furthermore, EPO increased the percentage of newly generated neurons while decreasing newly generated astrocytes following brain injury, without demonstrating long-term differences in the subventricular zone. These results suggest that EPO may neuroprotect and direct cell fate toward neurogenesis and away from gliogenesis in neonatal stroke.

Massive pulmonary hemorrhage (MPH) in newborn infants is a catastrophic event with a fatal result. The aim of this study was to assess the efficacy of high frequency oscillatory ventilation (HFOV) as a rescue therapy for MPH in newborn infants. Eighteen newborn infants with MPH refractory to conventional mechanical ventilation were treated with HFOV. Changes in oxygenation were assessed using arterial-alveolar oxygen tension ratio (a/APO2) and oxygenation index (OI) during HFOV. The most common underlying disorder of MPH was preterm patent ductus arteriosus (PDA). Thirteen out of 18 (72%) newborn infants with MPH responded to HFOV and survived. Five out of 18 (28%) did not respond to HFOV and died. There were no differences between responders and nonresponders in gestational age, birth weight, pre-HFOV OI, and age of MPH onset. In responders, there was a rapid increase in a/APO2 from 0.18+/-0.04 to 0.40+/-0.08 at 30 minutes after HFOV. There was also significant decrease in OI from 14.9+/-4.7 to 8.1+/-1.5 at 1 hour after HFOV. We conclude that HFOV shows rapid and dramatic improvements and has ultimately life-saving effects in MPH of newborn infants.

Co-culture system, in which two or more distinct cell types are cultured together, is advantageous in that it can mimic the environment of the in vivo niche of the cells. In this study, we presented a strategy to analyze the secretome of a specific cell type under the co-culture condition in serum-supplemented media. For the cell-specific secretome analysis, we expressed the mouse mutant methionyl-tRNA synthetase for the incorporation of the non-canonical amino acid, azidonorleucine into the newly synthesized proteins in cells of which the secretome is targeted. The azidonorleucine-tagged secretome could be enriched, based on click chemistry, and distinguished from any other contaminating proteins, either from the cell culture media or the other cells co-cultured with the cells of interest. In order to have more reliable true-positive identifications of cell-specific secretory bodies, we established criteria to exclude any identified human peptide matched to bovine proteins. As a result, we identified a maximum of 719 secreted proteins in the secretome analysis under this co-culture condition. Last, we applied this platform to profile the secretome of mesenchymal stem cells and predicted its therapeutic potential on osteoarthritis based on secretome analysis.