Abnormal deposition of collagen/elastic vascular fibres and prognostic significance in idiopathic interstitial pneumonias.
BACKGROUND
Vascular remodelling has recently been shown to be a promising pathogenetic indicator in idiopathic interstitial pneumonias (IIPs).


OBJECTIVE
To validate the importance of the collagen/elastic system in vascular remodelling and to study the relationships between the collagen/elastic system, survival and the major histological patterns of IIPs.


METHODS
Collagen/elastic system fibres were studied in 25 patients with acute interstitial pneumonia/diffuse alveolar damage, 22 with non-specific interstitial pneumonia/non-specific interstitial pneumonia and 55 with idiopathic pulmonary fibrosis/usual interstitial pneumonia. The Picrosirius polarisation method and Weigert's resorcin-fuchsin histochemistry and morphometric analysis were used to evaluate the amount of vascular collagen/elastic system fibres and their association with the histological pattern of IIPs. The association between vascular remodelling and the degree of parenchymal fibrosis in usual interstitial pneumonia (UIP) was also considered.


RESULTS
The vascular measurement of collagen/elastic fibres was significantly higher in UIP than in the lungs of controls, and in those with diffuse alveolar damage and those with non-specific interstitial pneumonia. In addition, the increment of collagen/elastic fibres in UIP varied according to the degree and activity of the parenchymal fibrosis. The most important predictors of survival in UIP were vascular remodelling classification and vascular collagen deposition.


CONCLUSIONS
A progressive vascular fibroelastosis occurs in IIP histological patterns, probably indicating evolutionarily adapted responses to parenchymal injury. The vascular remodelling classification and the increase in vascular collagen were related to survival in IIP and possibly play a role in its pathogenesis. Further studies are needed to determine whether this relationship is causal or consequential.
Parra
Edwin Roger
ER
Department of Pathology, Sao Paulo Medical School, University of São Paulo, Dr Arnaldo Avenue 455, São Paulo 01246-903, Brazil.
Kairalla
Ronaldo Adib
RA
de Carvalho
Carlos Roberto Ribeiro
CR
Capelozzi
Vera Luiza
VL
D000328:Adult; D000368:Aged; D003094:Collagen / Q000378:metabolism*; D004547:Elastic Tissue / Q000378:metabolism*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000098:blood supply*; D017563:Lung Diseases, Interstitial / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D014652:Vascular Diseases / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D014797:Vital Capacity / Q000502:physiology
D003094:Collagen