Canadian scientists, T. van Haaften et al.,from the University of Alberta reported their study results on using bone marrow-derived mesenchymal stem cell (BMSCs) to prevent alveolar destruction in an experimental model of bronchopulmonary dysplasia (BPD) in newborn rats. In a research paper published in the December 1st issue of Am J. Resp. & Critical Care Med., the investigators reported that they were able to improved survival and excerise tolerance concomitant with attenuating alevolar and lung vascular injury and pulmonary hypertension by intratracheal delivery of BMSCs. In vitro results showed BMSCs differentiating into type II alveolar epithelial cells (AEC2) following co-culturing BMSCs with lung tissue. Although BMSCs were able to migrate to the oxygen-damaged lung engraftment, the researchers noted that low engraftment of the BMSCs could not account for the observed therapeutic benefit following delivery of the BMSCs to the damaged tissue site. The authors surmised that a paracrine-mediated mechanism for preventing arrested alveolar and vascular growth. This hypothesis was supported by "in vitro results in which BMSC-derived conditioned medium prevented oxygen-induced AEC2 apoptosis, accelerated AEC2 wound healing, and enhanced endothelial cord formation."