Functional morphometry to estimate the alveolar surface area using a premature baboon model

Theodore Dassios, Mario Rüdiger, Donald McCurnin, Steven R. Seidner, Emma E. Williams, Anne Greenough, Marius Alexander Möbius

Research output: Contribution to journalArticlepeer-review

Abstract

The main respiratory pathophysiological process following premature birth is the delayed or arrested alveolar development that translates to a smaller alveolar surface area (SA). Histological morphometry is the gold standard method to measure the SA but requires invasive tissue sampling or the removal of the whole organ for analysis. Alternatively, the SA could be measured in living subjects by "functional morphometry"using Fick's first law of diffusion and noninvasive measurements of the ventilation to perfusion ratio (VA/Q). We herein aim to describe a novel functional morphometric method to measure SA using a premature baboon model. We used both functional morphometry and postmortem histological morphometry to measure SA in 11 premature baboons born at 135 days who received intensive care treatment for 14 days. For the calculation of the SA by functional morphology, we measured the septal wall thickness using microscopy, the alveolar arterial oxygen gradient using concurrent measurements of arterial pressure of O2 and CO2, and pulmonary perfusion using echocardiography and integrated Doppler signals. The median [interquartile range (IQR)] SA using functional morphometry was 3,100 (2,080-3,640) cm2 and using histological morphometry was 1,034 (634-1,210) cm2 (left lung only). The SA measured by functional morphometry was not related to the SA measured by histological morphometry. Following linear regression analysis, the V A/Q significantly predicted the histologically measured SA (R2 = 0.659, P = 0.002). In conclusion, functional measurements of ventilation to perfusion ratio could be used to estimate the alveolar surface area in prematurely born baboons and the ventilation perfusion ratio was the main determinant of the alveolar surface area.

Original languageEnglish (US)
Pages (from-to)209-215
Number of pages7
JournalJournal of applied physiology
Volume132
Issue number1
DOIs
StatePublished - Jan 2022

Keywords

  • Alveolar surface area
  • Fick's law
  • Morphometry
  • Prematurity
  • Stereology

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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