May 20, 2011

Lung Regeneration Using Stem Cells?

(Ivanhoe Newswire) "“ A newly discovered group of stem cells from normal adult human lungs have the ability to regenerate virtually all parts of an injured mouse lung.

The findings of Kajstura et al. also show organization of complete respiratory units in vivo within 14 days, including conducting airways and vessels. The authors used cell-surface c-kit receptors, known to mark hematopoietic and cardiac stem cells, to isolate and analyze these cells from adult lungs. They believe that c-kit"“positive lung stem cells preferentially contribute to lung repair after injury because they are capable of differentiating into whatever element is needed to form a functional lung unit. If this is true, the identification of these stem cells promises to overcome one of the major hurdles in human lung regeneration: the identification and isolation of a native lung cell that could be used to replenish functioning lung tissue in a patient with lung disease, averting the hazards of allogeneic transplantation or reprogramming.

The most provocative implication of the discovery of these cells concerns bioengineering. The field of bioengineered lung tissue sees clinical medicine on the distant horizon, but patients are living with airway transplants of devitalized tracheal matrix repopulated with their own epithelial cells. It is possible to grow well-organized rodent lung tissue beginning with an intact, devitalized lung matrix and embryonic lung cells and to observe a functional effect, if only briefly, when this tissue is implanted in live animals. Expanded, c-kit"“positive lung stem cells from a patient are an appealing parent for bioengineered tissue, but Kajstura et al. report no evidence that the observed respiratory units integrate sufficiently with the host vasculature or airways to support perfusion or ventilation. There are reasons to anticipate that such connections will develop.

SOURCE: New England Journal of Medicine, May 12, 2011