ANGIOGENESIS IN MICE WITH CHRONIC AIRWAY INFLAMMATION - STRAIN-DEPENDENT DIFFERENCES

Chronic inflammation is associated with blood vessel proliferation and enlargement and changes in vessel phenotype. We sought to determine w hether these changes represent different typos of angiogenesis and whe ther they are stimulus dependent. Chronic airway inflammation, produce d by infection with Mycoplasma pulmonis, was compared in strains of mi ce known to be resistant (C57BL/6) or susceptible (C3H). Tracheal vasc ularity, assessed in whole mounts after Lycopersicon esculentum lectin staining, increased in both strains at 1, 2, 4, and 8 weeks after inf ection, but the type of vascular remodeling was different. The number of vessels doubled in tracheas of C57BL/6 mice, with corresponding inc reases of capillaries and venules, In contrast, neither the number nor the length of vessels changed in C3H mice. Instead, vessel diameter a nd endothelial cell number doubled, and the proportion of venules doub led with a corresponding decrease of capillaries. Although the infecti on had no effect on baseline plasma leakage, in both strains it potent iated the leakage produced by substance P. We conclude that the same s timulus can result in blood vessel proliferation or enlargement, depen ding on the host response. Endothelial cells proliferate in. both case s, but in one case new capillaries form whereas in the other capillari es convert to venules.