Document Detail

Permeability of peritoneal and glomerular capillaries: what are the differences according to pore theory?
MedLine Citation:
PMID:  21555410     Owner:  NLM     Status:  MEDLINE    
Pore and fiber-matrix theory can both be used to model the peritoneal and glomerular filtration barriers in an attempt to shed light on their differing structure-function relationships. The glomerular filtration barrier (GFB) is structurally more specialized, morphologically complex, and also highly dynamic; but paradoxically, because of its uniformity, it conforms more closely to the predictions of pore theory than does the peritoneum, and it in fact resembles a more simple synthetic membrane. Compared with the peritoneal capillary wall, the GFB has no transcellular "third" pores (aquaporins), and it is far less leaky and more size-selective to proteins, mainly as a result of having far fewer "large" pores. It does have charge-selective properties, although these are considered much less important in excluding albumin than was once thought, and it is also able to select polymers according to their shape and flexibility. Even this property might reflect the relative uniformity of the GFB, which has a high diffusion area and short diffusion distances, compared with the peritoneal barrier, which behaves more like a gel filtration column. Furthermore, the length of the diffusion path across the peritoneal membrane is much greater for small solutes, given the relatively high ultrafiltration coefficient for that membrane compared with the GFB--a situation that reflects both the tortuosity of the interendothelial clefts and the distribution of peritoneal capillaries within the interstitium. These comparisons reveal the peritoneal barrier as a relatively complex structure to model; and yet this model may be more representative of the general microcirculation, and thus shed light on systemic endothelial function in renal failure.
Bengt Rippe; Simon Davies
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis     Volume:  31     ISSN:  1718-4304     ISO Abbreviation:  Perit Dial Int     Publication Date:    2011 May-Jun
Date Detail:
Created Date:  2011-05-10     Completed Date:  2012-02-13     Revised Date:  2012-08-08    
Medline Journal Info:
Nlm Unique ID:  8904033     Medline TA:  Perit Dial Int     Country:  Canada    
Other Details:
Languages:  eng     Pagination:  249-58     Citation Subset:  IM    
Department of Nephrology, Lund University, Sweden.
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MeSH Terms
Capillary Permeability*
Electrophysiological Processes
Kidney Glomerulus / blood supply*,  metabolism*
Peritoneum / blood supply*,  metabolism*

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