Bronchial artery revascularization protects pulmonary endothelium after lung transplant
NEW YORK (Reuters Health) – Experiments in dogs indicate that in the early stages after lung transplantation, bronchial artery revascularization (BAR) protects pulmonary endothelium and type II pneumocytes, German researchers report in the January 15th issue of the American Journal of Respiratory and Critical Care Medicine.
Dr. Martha-Maria Gebhard, from the University of Heidelberg, and colleagues performed left lung transplantations in 12 beagles. Six of the animals also underwent BAR.
The researchers evaluated the effect of BAR on lung cells after 6 hours of ischemia. In both groups of transplanted dogs, at 2 hours and 4 hours after reperfusion, activity of carboxypeptidase M (a marker enzyme for pneumocytes type I) and lactate dehydrogenase were higher compared with control dogs (p < 0.01).
However, at 2 hours after reperfusion, alkaline phosphatase and angiotensin-converting enzyme levels, as seen in bronchoalveolar lavage fluid, were significantly elevated in dogs that underwent conventional transplantation compared with dogs that underwent BAR (p < 0.05) and control animals (p < 0.01), the German team found.
Dr. Gebhard and associates conclude that "BAR in lung transplantation has a positive impact on bronchoalveolar lavage concentrations of injury marker enzymes for pneumocytes type II and pulmonary endothelium in the early postischemic period after lung transplantation."
These findings "favor the hypothesis that the bronchial circulation could compensate pulmonal arterial perfusion deficit by using bronchopulmonary anastomoses."
They add that "whether BAR possibly affects long-term function of the transplanted lung and delays onset of bronchiolitis obliterans syndrome by limiting ischemia-reperfusion injury of the graft needs further study."