The observation that ferritin is excluded from the luminal vesicles and the luminal surface of endothelial cells has led one of us to reintroduce the idea that the molecular sieving properties of the capillary wall may reside in an endocapillary layer rather than in the dimensions of pores through or between the endothelial cells. It is suggested that the endocapillary layer is a three-dimensional network formed by the fibrous chains of the membrane glycoproteins of the endothelial cell coat reinforced by the absorption of plasma proteins. It may be identified with the ruthenium red staining layer described by Luft (1966). The latter not only appears to line the luminal surface of the capillary but also appears to fill the wide regions of the intercellular clefts and merge with the basal lamina. It is found covering the fenestrations when these are present and can also be seen lining the cytoplasmic vesicles. In this short paper, we wish to draw attention to the possible relationships for flow and diffusion through such a membrane, and so offer a quantitative basis for assessing the theory.
|Original language||English (US)|
|Number of pages||4|
|State||Published - 1980|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine