TY - JOUR
T1 - Functional morphometry to estimate the alveolar surface area using a premature baboon model
AU - Dassios, Theodore
AU - Rüdiger, Mario
AU - McCurnin, Donald
AU - Seidner, Steven R.
AU - Williams, Emma E.
AU - Greenough, Anne
AU - Möbius, Marius Alexander
N1 - Funding Information:
This project was partially funded by King’s College London 2018 Medical Research Council Confidence in Concept Award through the King’s Health Partners’ Research and Development Challenge Fund.
Publisher Copyright:
© 2022 the American Physiological Society.
PY - 2022/1
Y1 - 2022/1
N2 - 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.
AB - 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.
KW - Alveolar surface area
KW - Fick's law
KW - Morphometry
KW - Prematurity
KW - Stereology
UR - http://www.scopus.com/inward/record.url?scp=85123079619&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.00644.2021
DO - 10.1152/japplphysiol.00644.2021
M3 - Article
AN - SCOPUS:85123079619
SN - 8750-7587
VL - 132
SP - 209
EP - 215
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 1
ER -