Eun Sun Kim, Yun Sil Chang, Soo Jin Choi, Jin Kyu Kim, Hey Soo Yoo, So Yoon Ahn, Dong Kyung Sung, Soo Yoon Kim, Ye Rim Park, Won Soon Park, Kim, Eun Sun, Chang, Yun Sil, Choi, Soo Jin, Kim, Jin Kyu, Yoo, Hey Soo, Ahn, So Yoon, Sung, Dong Kyung, Kim, Soo Yoon, Park, Ye Rim, and Park, Won Soon
Background: Human umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) attenuate hyperoxic neonatal lung injury primarily through anti-inflammatory effects. We hypothesized that intratracheal transplantation of human UCB-derived MSCs could attenuate Escherichia coli (E. coli)-induced acute lung injury (ALI) in mice by suppressing the inflammatory response.Methods: Eight-week-old male ICR mice were randomized to control or ALI groups. ALI was induced by intratracheal E. coli instillation. Three-hours after E. coli instillation, MSCs, fibroblasts or phosphate-buffered saline were intratracheally administered randomly and survival was analyzed for 7 days post-injury. Lung histology including injury scores, myeloperoxidase (MPO) activity, and protein levels of interleukin (IL)-1α, IL-1β, IL-6, tumor necrosis factor (TNF)-α, and macrophage inflammatory protein (MIP)-2 as well as the wet-dry lung ratio and bacterial counts from blood and bronchoalveolar lavage (BAL) were evaluated at 1, 3, and 7 days post-injury. Levels of inflammatory cytokines in the lung were also profiled using protein macroarrays at day 3 post-injury which showed peak inflammation.Results: MSC transplantation increased survival and attenuated lung injuries in ALI mice, as evidenced by decreased injury scores on day 3 post-injury and reduced lung inflammation including increased MPO activity and protein levels of IL-1α, IL-1β, IL-6, TNF-α, and MIP-2 on day 3 and 7 post-injury. Inflammatory cytokine profiles in the lungs at day 3 post-injury were attenuated by MSC transplantation. MSCs also reduced the elevated lung water content at day 3 post-injury and bacterial counts in blood and BAL on day 7 post-injury.Conclusions: Intratracheal transplantation of UCB-derived MSCs attenuates E. coli-induced ALI primarily by down-modulating the inflammatory process and enhancing bacterial clearance. [ABSTRACT FROM AUTHOR]