Editors' ChoiceLung Biology

A Breath of Fresh Alveoli

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Science Translational Medicine  22 Aug 2012:
Vol. 4, Issue 148, pp. 148ec151
DOI: 10.1126/scitranslmed.3004770

Unlike the liver, which is famously able to regenerate itself after partial resection, the conventional wisdom has long been that the adult human lung was not capable of a similar feat. However, some adult animal models of unilateral lung removal have clearly demonstrated that the remaining lung is capable of compensatory lung regrowth, and long-term follow-up of children after partial lung removal has suggested the same. Whether adult human lungs could truly regrow new lung tissue after a similar insult has remained controversial; most experts believed that the modest postoperative gains in lung size in adults resulted from overdistention of the remaining alveoli rather than regrowth. Now, Butler and colleagues report on a case that challenges this notion.

In this brief report, the authors describe the case of a 33-year-old woman who had one cancer-ridden lung removed in 1995. As expected, 3 months after the surgery, her vital capacity—a common test of lung function that measures the maximum amount of air that can be expired after a maximum inhalation—was about half of its preoperative value. Over a 15-year follow-up period, her vital capacity gradually increased until she had regained about half of what she had lost in the surgery. She also had lung imaging tests performed over the same time interval that demonstrated a rise in lung tissue volume, without evidence of regional hyperinflation.

Although not conclusive, this evidence is strongly suggestive of regrowth of new lung tissue over time. Additional studies are needed to confirm, with more mechanistic and definitive analyses, whether the adult human lung is truly capable of generating new alveolar tissue after lung resection, which could have important ramifications for patients with both acute and chronic lung disease.

J. P. Butler et al., Evidence for adult lung growth in humans. N. Engl. J. Med. 367, 244–247 (2012). [Full Text]

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