Total number and mean size of alveoli in mammalian lung estimated using fractionator sampling and unbiased estimates of the Euler characteristic of alveolar openings
Open Access
- 12 February 2004
- journal article
- research article
- Published by Wiley in The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology
- Vol. 277A (1), 216-226
- https://doi.org/10.1002/ar.a.20012
Abstract
Estimation of alveolar number in the lung has traditionally been done by assuming a geometric shape and counting alveolar profiles in single, independent sections. In this study, we used the unbiased disector principle to estimate the Euler characteristic (and thereby the number) of alveolar openings in rat lungs and rhesus monkey lung lobes and to obtain robust estimates of average alveolar volume. The estimator of total alveolar number was based on systematic, uniformly random sampling using the fractionator sampling design. The number of alveoli in the rat lung ranged from 17.3 · 106 to 24.6 · 106, with a mean of 20.1 · 106. The average number of alveoli in the two left lung lobes in the monkey ranged from 48.8 · 106 to 67.1 · 106 with a mean of 57.7 · 106. The coefficient of error due to stereological sampling was of the order of 0.06 in both rats and monkeys and the biological variation (coefficient of variance between individuals) was 0.15 in rat and 0.13 in monkey (left lobe, only). Between subdivisions (left/right in rat and cranial/caudal in monkey) there was an increase in variation, most markedly in the rat. With age (2−13 years) the alveolar volume increased 3-fold (as did parenchymal volume) in monkeys, but the alveolar number was unchanged. This study illustrates that use of the Euler characteristic and fractionator sampling is a robust and efficient, unbiased principle for the estimation of total alveolar number in the lung or in well-defined parts of it. Anat Rec Part A 274A:216–226, 2004.Keywords
This publication has 32 references indexed in Scilit:
- Alveolar inflation during generation of a quasi-static pressure/volume curve in the acutely injured lungCritical Care Medicine, 2003
- The efficiency of systematic sampling in stereology — reconsideredJournal of Microscopy, 1999
- Formation of Pulmonary Alveoli and Gas-Exchange Surface Area: Quantitation and RegulationAnnual Review of Physiology, 1996
- The connEulor: Unbiased estimation of connectivity using physical disectors under projectionBone, 1993
- Assessment of particle retention and clearance in the intrapulmonary conducting airways of hamster lungs with the fractionator1Journal of Microscopy, 1990
- Morphometric Estimation of Regional Differences in the Rat LungExperimental Lung Research, 1990
- Techniques for the Determination of Particle Deposition in Lungs of HamstersJournal of Aerosol Medicine, 1989
- Some new, simple and efficient stereological methods and their use in pathological research and diagnosisAPMIS, 1988
- Respiratory Bronchiolitis Following Long-Term Ozone Exposure in Bonnet Monkeys: A Morphometric StudyExperimental Lung Research, 1985
- Morphometric estimation of pulmonary diffusion capacity: I. Model and methodRespiration Physiology, 1971