SELECTED ARTICLES FROM THE RECENT LITERATURE 2008

5/28/2008

Interruption of Lymphatics May Cause Submucosal Edema in Asthma

Summary
The author of this article had previously studied the pathology of fatal asthma and based upon this work, classified fatal asthmatics into two types. In type 1, smooth muscle bundle thickening occurred only in large airways, and in type 2, this smooth muscle bundling thickening occurred throughout the lung. The author postulated that where smooth muscle bundle thickening occurred there would be interruption of lymphatics, and that this interruption might predispose to submucosal edema.

This hypothesis was investigated in the present article. The findings were that the distribution areas of lymphatics in the larger airways of both type 1 and type 2 asthmatics were significantly decreased compared to controls. In addition, type 1 asthmatics contained much less lymphatics in the large airways than did type 2. The lymphatics around the smaller airways were reduced in both phenotypes and there was no difference between the two. In both groups, airway lymphatics in fatal asthmatics were interrupted by thickened smooth muscle layers and by fibrous tissue.

The authors thus concluded that fatal asthma lymphatics were decreased in the airway walls, and that this reduction was related to the presence of hypertrophied smooth muscle bundles and fibroconnective tissue. They suggested that because of this, lymphatic clearance was reduced and that this might predispose to mucosal edema.

Reference
Ebina M. Remodeling of airway walls in fatal asthmatics decreases lymphatic distribution; beyond thickening of airway smooth muscle layers. Allergology International 2008; 57 (presently available online - page number not yet assigned).

 

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