Cells derived from the circulation contribute to the repair of lung injury.
Bone marrow (stem/progenitor) cells have been shown to "differentiate" into cells in multiple tissues, including lung. A low number of hematopoietic stem/progenitor cells also circulate in peripheral blood. The physiologic roles of these cells are still uncertain. This study was designed to test, using parabiotic mice that were joined surgically, whether stem/progenitor cells in blood contributed to the regeneration of lung after injury. Parabiotic mice were generated surgically by joining green fluorescent protein transgenic mice and wild-type littermates. These mice developed a common circulation (approximately 50% green cells in blood) by 2 weeks after surgery. The wild-type mouse was either uninjured or lethally irradiated or received intratracheal elastase or the combination of radiation with intratracheal elastase injection. Radiation or the combination of radiation with elastase significantly increased the proportion of bright green cells in the lungs of the wild-type mice. Morphologically, interstitial monocytes/macrophages, subepithelial fibroblast-like interstitial cells, and additionally type I alveolar epithelial cells immunostained for green fluorescent protein in wild-type mice. Approximately 5 to 20% of lung fibroblasts primary cultured from injured wild-type mice were green fluorescent protein expressing cells, indicating their blood derivation. This study demonstrates that stem/progenitor cells in blood contribute to the repair of lung injury in irradiated mice.
University of Nebraska Medical Center, Department of Internal Medicine, Pulmonary and Critical Care Medicine Section 985125, Nebraska Medical Center, Omaha, NE 68198-5125, USA.
Shinji
S
Abe
Craig
C
Boyer
Xiangde
X
Liu
Fu Qiang
FQ
Wen
Tetsu
T
Kobayashi
Qiuhong
Q
Fang
Xingqi
X
Wang
Mitsuyoshi
M
Hashimoto
J Graham
JG
Sharp
Stephen I
SI
Rennard
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D004798:Enzymes / Q000009:adverse effects; D004847:Epithelial Cells / Q000502:physiology; D005347:Fibroblasts / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D008168:Lung / Q000503:physiopathology; D008171:Lung Diseases / Q000209:etiology / Q000503:physiopathology*; D051379:Mice; D009000:Monocytes / Q000502:physiology; D010196:Pancreatic Elastase / Q000009:adverse effects; D010227:Parabiosis; D017564:Radiation Pneumonitis / Q000209:etiology / Q000503:physiopathology; D020545:Respiratory Mucosa / Q000503:physiopathology; D014916:Whole-Body Irradiation / Q000009:adverse effects; D014945:Wound Healing / Q000502:physiology*
D004798:Enzymes; D010196:Pancreatic Elastase