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Heteropore Characteristics of Type I‐ and Type II‐Like Rat Alveolar Epithelial Cell Monolayers
Author(s) -
KIM YONG HO,
BOROK ZEA,
CRANDALL EDWARD D,
KIM KWANGJIN
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.612.16
Subject(s) - monolayer , chemistry , diffusion , permeability (electromagnetism) , biophysics , hexagonal crystal system , cell type , cell , crystallography , membrane , biology , biochemistry , physics , thermodynamics
Utilizing primary rat alveolar epithelial cell monolayers (RAECM) grown in the absence (type I cell‐like phenotype, RAECM‐I) or presence (type II cell‐like phenotype, RAECM‐II) of keratinocyte growth factor, we estimated apparent permeability coefficients (P app ) for nine hydrophilic solutes (molecular radii from 0.14 to 2.29 nm) in the apical‐to‐basolateral direction. Under the assumption that passive restricted diffusion of these solutes takes place via equivalent water‐filled pores, pore sizes based on these P app using Renkin analysis were determined. Results showed that both RAECM‐I and ‐II can best be characterized by two populations of pores. Radii of small and large pores of 0.9 and 4.5 nm in RAECM‐I, and 1.1 and 9.7 nm in RAECM‐II, were estimated. About 98% and 2% of total pore area can be ascribed to small and large pore areas, respectively, in both RAECM‐I and ‐II. However, the number of small pores in RAECM‐II (7.5×10 9 /cm 2 ) was 7‐fold greater than that in RAECM‐I, while the number of large pores (1.4×10 6 /cm 2 ) was about the same in both RAECM‐I and ‐II. These data suggest that passive diffusion of hydrophilic solutes is dependent on the size, distribution and number of equivalent heteropores across alveolar epithelium and the homotypic/heterotypic junctions between alveolar epithelial cells. (Funded by: NIH; Hastings & Whittier Foundations.)