Stereological methods: A new approach in the assessment of pulmonary emphysema

Abstract

In order to develop a reliable and sensitive method for studying the development and progression of pulmonary emphysema, we compared stereological indices with the usual index for grade of emphysema, i.e., the mean linear intercept (Lm), in elastase‐induced emphysema in mice. The Lm and stereological indices, including volumes of total lung tissue (V(lt)), airspaces (V(air)), and surface area of alveolar walls (S(alv)), were determined in 5‐μm, H&E‐stained, paraffin‐embedded lung sections from elastase‐ (n = 7) or saline‐treated (n = 8) mice. The indices were measured by point counting, using Cavalieri's principle (V(lt) and V(air)) or by counting intersections of alveolar walls with test lines of a known length (S(alv) and Lm). Elastase treatment resulted in a significant increase of Lm and of V(air), both indicating airspace enlargement, and in a significant decrease of V(lt) and S(alv), indicating destruction of alveolar walls. Between each of the stereological indices and the Lm, significant correlations were found when all lungs were included, but not when the emphysematous lungs were considered separately. We conclude that stereological methods can be powerful morphometric tools for studying pulmonary emphysema development and progression, since they give information not only about the grade of airspace enlargement but also about the grade of destruction of alveolar walls. Based on this unique property, stereological methods also allow a distinction between pulmonary emphysema and unrelated conditions with dilatation of airspaces only. © 1996 Wiley‐Liss, Inc.

Sequential targeted deficiency of SP-A and -D leads to progressive alveolar lipoproteinosis and emphysema

“…The stereological analysis revealed significant increases in both mean linear intercept length and v of air spaces, clearly demonstrating air space enlargement in the SP-AD (Ϫ/Ϫ) mice. In addition, there was a decrease in the alveolar epithelial surface fraction, which indicates a loss of gas exchange surface per unit volume (12), in the SP-AD (Ϫ/Ϫ) mice. Because the lungs of 3-wk-old SP-AD (Ϫ/Ϫ) mice look qualitatively normal (data not shown), the changes in lung structure in the older mice are more likely the result of progressive alveolar wall destruction than a primary failure of alveolar septation.…”

Bright field segmentation tomography (BFST) for use as surface identification in stereomicroscopy

“…This serves an essential function in analytical assessment of pulmonary emphysema. Pulmonary emphysema is a condition of the lung characterized by abnormal, permanent enlargement of airspaces with subsequent destruction of their walls [10]. Currently, cross-sections of lung tissue that are perceived under the stereomicroscope cannot provide the discrimination needed to accurately detect and measure the alveoli.…”

Animal models of pulmonary emphysema: a stereologist's perspective

“…In view of the anatomical definition, however, it is not sufficient to reveal abnormal permanent airspace enlargement alone to conclude that emphysema is present. Reliable assessment of the presence of emphysema in any animal model requires the destruction of alveolar walls to be additionally demonstrated [14,15], such as a decrease in total alveolar wall volume, total alveolar surface area, total capillary length and/or total number of alveoli [18,24,25].…”

“…Since then, it has been adapted by many others. The attractiveness of this model is that a single hit, the instillation of a bolus of an elastolytic proteinase, such as porcine pancreatic or human neutrophil elastase, results in the loss of alveolar walls, as judged by stereology [24], whereas nonelastolytic proteinases failed to induce emphysematous lesions [28]. However, the desired effect of elastase is frequently limited to a narrow window of dosage, below which no significant loss of alveoli is observed, whereas a higher dose may result in severe pulmonary haemorrhage and high mortality [29,30].…”