The difference of neovascularization in early intra‐alveolar fibrosis between nonspecific interstitial pneumonia and usual interstitial pneumonia

Of the idiopathic interstitial pneumonias ( IIPs ), usual interstitial pneumonia ( UIP ) and diffuse alveolar damage ( DAD ) usually have poor prognoses. The prognoses of cryptogenic organizing pneumonia ( COP ) and nonspecific interstitial pneumonia ( NSIP ) are usually more favorable. Although several reports have described neovascularization in COP and UIP , this aspect of UIP has not been compared with NSIP . In this study, we evaluated neovascularization in intra‐alveolar fibrotic lesion of cases of fibrosing NSIP (f‐ NSIP ) ( n = 26) and UIP ( n = 25). In the f‐ NSIP group, a considerable degree of neovascularization was observed compared to the UIP group and bud type intra‐alveolar fibrosis showed a greater degree of neovascularization compared to the mural‐incorporation and obliterative types of intra‐alveolar fibrosis. Real‐time reverse transcription polymerase chain reaction revealed a significantly greater expression of VEGF ‐ A mRNA in f‐ NSIP than in UIP . The expression of matrix metalloproteinase‐2 ( MMP ‐2) mRNA also showed significantly higher in f‐ NSIP than UIP . The greater VEGF ‐ A and MMP ‐2 expression may play a role in the pathogenesis of neovascularization in early intra‐alveolar fibrotic lesions in f‐ NSIP .