title: Cadmium-chloride-induced air-space enlargement with interstitial pulmonary fibrosis is not associated with destruction of lung elastin. Implications for the pathogenesis of human emphysema.
abstract: To determine whether lung elastin is lost during the evolution of cadmium-induced air-space enlargement with pulmonary fibrosis, the lung elastin of 5- to 7-day-old golden Syrian hamster pups was radiolabeled by giving [3H]valine. At maturity, a single intratracheal instillation of 0.5 ml of 0.025% CdCl2 solution was given. Lung mechanics, histologic examination, and biochemistry were studied 5, 10, 21, 42, 105, and 180 days after the cadmium treatment. The animals developed fibrosis and air-space enlargement with decreased lung volumes, compliance, and forced expiratory flow; their functional residual capacity was increased. The total lung collagen and total lung elastin were increased, but there was no loss of radiolabel in lung elastin. We conclude that CdCl2-induced air-space enlargement with pulmonary fibrosis is not accompanied by loss of neonatally formed lung elastic fibers. We hypothesize that air-space enlargement with fibrosis represents a stereotyped response of the lung to fibrosing injuries, which we hypothesize is due to forces from more fibrotic and atelectatic areas causing overdistension of less abnormal air spaces. The air-space enlargement of fibrosing human diseases such as sarcoidosis and eosinophilic granuloma may have a similar basis. Evidence is reviewed that human centrilobular emphysema may be a form of focal air-space enlargement with interstitial fibrosis; there may be mechanisms in addition to elastase-antielastase imbalance that cause human emphysema.
authors: Pulmonary Center, Boston University School of Medicine.
authors: G L
authors: GL
authors: Snider
authors: E C
authors: EC
authors: Lucey
authors: B
authors: B
authors: Faris
authors: Y
authors: Y
authors: Jung-Legg
authors: P J
authors: PJ
authors: Stone
authors: C
authors: C
authors: Franzblau
mesh_terms: D000818:Animals; D002104:Cadmium; D019256:Cadmium Chloride; D004549:Elastin / Q000378:metabolism*; D004646:Emphysema / Q000209:etiology*; D005540:Forced Expiratory Flow Rates; D006801:Humans; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D009929:Organ Size; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D014109:Total Lung Capacity; D014797:Vital Capacity
chemical_list: D002104:Cadmium; D004549:Elastin; D019256:Cadmium Chloride