On the diaphragm across fenestrae of capillary endothelium

Friederici, H.H.R.

doi:10.1016/s0022-5320(69)80024-9

Cited by 43 publications

(11 citation statements)

References 5 publications

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“…Among the latter, the plasmalemmal vesicles in the endothelium of muscular capillaries and the fenestrae in that of visceral capillaries are of particular importance, since they have been implicated in the movement of water and water-soluble molecules across the endothelial layer (2,(3)(4)(5)(6)(7)(8) . A number of incidental observations have already mentioned an uneven distribution of fenestrae and vesicles in a variety of capillaries (6,(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) . Moreover, in a recent paper (8) we have distinguished in the endothelial 1 28 cell of the blood capillaries of the rat diaphragm four differentiated parts, and we have shown that these parts participate unequally in the transport of myoglobin used as an exogenous tracer .…”

Section: Introductionmentioning

confidence: 99%

Morphometric Data on the Endothelium of Blood Capillaries

Simionescu

Simiónescu

Palade

1974

The Journal of Cell Biology

274

118

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Local differentiations within the endothelium of both muscular (diaphragm, myocardium) and visceral (pancreas, jejunal villi) capillaries have been studied in rats on sectioned and freeze-cleaved preparations . Four distinct parts have been recognized in the endothelial cells of all these vessels on the basis of subcellular components present in each part and on the basis of variations in the local frequency of plasmalemmal vesicles : (a) the parajunctional zone, (b) the peripheral zone, (c) the organelle region, and (d) the nuclear region . Our data indicate that -16, -7 .0, and 8 .5% of the endothelial cytoplasmic volume (in the peripheral zone) is accounted for by vesicles, their content, and their membranes, respectively . The average density of vesicular openings per µm 2 is 78 in diaphragm, 89 in myocardium, 25 in pancreas, and 10 in jejunal mucosa capillaries . The frequency of fenestrae is 1 .7 times as high in jejunal (26/µm 2) as in pancreatic capillaries (15/µm2), the corresponding fractional areas being -9 .5 and -6 0/,, respectively, of the endothelial surface . Intercellular spaces occupy a relatively small area (-0 .08 to 0 .2%) of the inner endothelial surface .

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Section: Introductionmentioning

confidence: 99%

Morphometric Data on the Endothelium of Blood Capillaries

Simionescu

Simiónescu

Palade

1974

The Journal of Cell Biology

274

118

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“…They are round openings or windows cutting through the endothelial cell, have a constant diameter of 63-68 nm, and occur only in the attenuated parts of the cell, in clusters referred to as ''sieve plates'' (5,9). In en face electron microscopic images, the fenestrae appear circular, but several studies have shown that they have an 8-fold symmetry (10,11).…”

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confidence: 99%

PV-1 is a component of the fenestral and stomatal diaphragms in fenestrated endothelia

Stan

Kubitza

Palade

1999

Proc. Natl. Acad. Sci. U.S.A.

238

245

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PV-1 is a novel endothelial protein shown by immunocytochemical tests to be specifically associated with the stomatal diaphragms of caveolae in lung endothelium. Although the highest expression levels of both mRNA and protein are in the lung, PV-1 also has been found to be expressed in other organs. Using a specific antibody to the extracellular domain of PV-1, we have extended the survey on the presence of this protein at light and electron microscope level in several rat organs. Here we show that by immunofluorescence the antibody recognizes with high specificity the endothelium of the fenestrated peritubular capillaries of the kidney and those of the intestinal villi, pancreas, and adrenals. By immunolocalization at electron microscope level, the antibody recognizes specifically the diaphragms of the fenestrae and the stomatal diaphragms of caveolae and transendothelial channels in the endothelia of these vascular beds. No signal was detected in the continuous endothelium of the heart, skeletal muscle, intestinal muscularis, or brain capillaries or the nondiaphragmed fenestrated endothelium of kidney glomeruli. Taken together, our findings define the only antigen to be localized thus far in fenestral diaphragms. They also show that the stomatal diaphragms of caveolae and transendothelial channels and the fenestral diaphragms might be biochemically related, in addition to being morphologically similar structures.

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“…30,31 Clinical nephrologists are also aware that proteinuria, sometimes in the nephrotic range, is a potential adverse effect of infusing anti-vascular endothelial growth factor (anti-VEGF) antibodies into patients who undergo antiangiogenesis treatment for cancer. 32 Because VEGF is critical for normal glomerular endothelial cell differentiation, 33 a proteinuric response to VEGF inhibition certainly is in keeping with a role of the glomerular endothelium in forming the glomerular protein barrier.…”

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confidence: 95%

“…26,27 Fenestral pores also have an octagonal symmetry. 28 -30 Their diaphragms appear as a thin (5 to 7 nm) protein barrier anchored to the rim by a central knob or density 31 connected by thin radial fibrils, 32 starting at the rim and interweaving into a central mesh. 29 Perfusion fixation of vascular beds with these fenestrated endothelia reveal the presence of large (up to 400 nm) tufts, or so-called fascinae fenestrae, on the luminal side of these diaphragms.…”

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confidence: 99%

“…As discussed, although many laboratories agree on the lack of diaphragms in mature glomerular fenestrae, micrographs of glomerular endothelial cells with fenestrae subtended by diaphragms have been reported in the literature. [21][22][23]32,51 In none of these reports, however, is there a careful morphometric analysis evaluating heterogeneity or possible impact on function. One group first reported that glomerular fenestrae have diaphragms, 21 whereas, in a subsequent article, they reported a lack 22 (compare Figures 7a and 1 in the respective articles).…”

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confidence: 99%

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