Diffusional permeability of rabbit mesothelium

Zocchi, Luciano; Raffaini, A.; Agostoni, Emilio; Cremaschi, D.

doi:10.1152/jappl.1998.85.2.471

Cited by 18 publications

(50 citation statements)

References 26 publications

(42 reference statements)

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“…Mesothelial cells are joined in the apical part of the intercellular space by junctional complexes [15,16,18,[19][20][21][22], comprising 1-5 stranded tight junctions 8-9 nm wide, similar to those of venular endothelium [19]. Accordingly, in line with the notion that openings in these junctions represent the diffusional pathway for small solutes [45][46][47][48], the permeability of the mesothelium to small solutes is similar to that of microvascular endothelium [40,41,43]. Finally, numerous free cytoplasmic vesicles, 40-60 nm in diameter, are observed in mesothelial cells [15,16,[18][19][20][21][22]25]; coated vesicles, responsible for receptor-mediated endocytosis were also found [15].…”

Section: Morphological Basis Of Transpleural Exchangementioning

confidence: 97%

“…They also contribute to reducing friction between the visceral and parietal mesothelia, through the glycoproteins rich in hyaluronic acid (secreted by mesothelial cells) they entrap [36]. Phospholipids are adsorbed to the apical surface of mesothelial cells [38,39]: they provide boundary lubrication (appropriate for the slowly moving pleurae) at points where no liquid is interposed between cells, and reduce mesothelial permeability [40][41][42][43], as they do in epithelia [44]. Mesothelial cells are joined in the apical part of the intercellular space by junctional complexes [15,16,18,[19][20][21][22], comprising 1-5 stranded tight junctions 8-9 nm wide, similar to those of venular endothelium [19].…”

Section: Morphological Basis Of Transpleural Exchangementioning

confidence: 99%

“…Fibres (type I and III collagen, elastin) are distributed with varying density and orientation in the interstitial matrix (glycoprotein, proteoglycans and water), organised in different layers. Water and solutes flow in the free channels between fibres; the restriction to diffusion of water and solutes (including macromolecules) offered by the submesothelial connective tissue is negligible [40][41][42][43]. Connective tissue thickness determines the overall thickness of a serosa (mesothelial cells being only 2 mm thick [18]) and it varies across species, serosae, and regions of a serosa.…”

Section: Morphological Basis Of Transpleural Exchangementioning

confidence: 99%

“…Indeed, the value is similar to Palb directly measured in the mesothelium (0.18610 -5 cm?s -1 [42]). Palb and Pd of the parietal mesothelium and the underlying connective tissue to various molecules (from H 2 O to dextran 2,000 kDa, ranging in radius (a) 0.14-27.9 nm) was obtained from fluxes of labelled molecules across the parietal pericardium [40][41][42][43]. Unlike the pleura, this serosa is easily accessible in rabbits, and wellpreserved specimens of it can be obtained and studied in vitro.…”

Section: Permeability Characteristicsmentioning

confidence: 99%

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Physiology and pathophysiology of pleural fluid turnover

Zocchi¹

2002

Eur Respir J

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175

102

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Tight control of the volume and composition of the pleural liquid is necessary to ensure an efficient mechanical coupling between lung and chest wall. Liquid enters the pleural space through the parietal pleura down a net filtering pressure gradient. Liquid removal is provided by an absorptive pressure gradient through the visceral pleura, by lymphatic drainage through the stomas of the parietal pleura, and by cellular mechanisms. Indeed, contrary to what was believed in the past, pleural mesothelial cells are metabolically active, and possess the cellular features for active transport of solutes, including vesicular transport of protein. Furthermore, the mesothelium was shown, on the basis of recent experimental evidence, both in vivo and in vitro, to be a less permeable barrier than previously believed, being provided with permeability characteristics similar to those of the microvascular endothelium. Direct assessment of the relative contribution of the different mechanisms of pleural fluid removal is difficult, due to the difficulty in measuring the relevant parameters in the appropriate areas, and to the fragility of the mesothelium. The role of the visceral pleura in pleural fluid removal under physiological conditions is supported by a number of findings and considerations.Further evidence indicates that direct lymphatic drainage through the stomas of the parietal pleura is crucial in removing particles and cells, and important in removing protein from the pleural space, but should not be the main effector of fluid removal. Its importance, however, increases markedly in the presence of increased intrapleural liquid loads. Removal of protein and liquid by transcytosis, although likely on the basis of morphological findings and suggested by recent indirect experimental evidence, still needs to be directly proven to occur in the pleura. When pleural liquid volume increases, an imbalance occurs in the forces involved in turnover, which favours fluid removal. In case of a primary abnormality of one ore more of the mechanisms of pleural liquid turnover, a pleural effusion ensues. The factors responsible for pleural effusion may be subdivided into three main categories: those changing transpleural pressure balance, those impairing lymphatic drainage, and those producing increases in mesothelial and capillary endothelial permeability. Except in the first case, pleural fluid protein concentration increases above normal: this feature underlies the classification of pleural effusions into transudative and exudative. Eur Respir J 2002; 20: 1545-1558. The thin layer of liquid present between the pleural surfaces has the important function of providing the mechanical coupling between the chest wall and lung, which ensures instantaneous transmission of perpendicular forces between the two structures, and allows their sliding in response to shearing forces [1,2]. It also provides lubrication of the reciprocal motions of the two structures during breathing. Two views, in part compatible, exist on the nature of t...

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Section: Morphological Basis Of Transpleural Exchangementioning

confidence: 97%

Section: Morphological Basis Of Transpleural Exchangementioning

confidence: 99%

Section: Morphological Basis Of Transpleural Exchangementioning

confidence: 99%

Section: Permeability Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Physiology and pathophysiology of pleural fluid turnover

Zocchi¹

2002

Eur Respir J

Self Cite

175

102

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show abstract

“…Αυτές οι ίνες διατάσσονται με συγκεκριμένη κατεύθυνση και προσανατολισμό, ενώ είναι τοποθετημένα σε διάφορα στρώματα μέσα στην ενδιάμεση ουσία (interstitial matrix) η οποία εμπεριέχει: γλυκοπρωτεΐνες, πρωτεογλυκάνες και νερό, τα οποία ρέουν ενδιάμεσα σε αυτά τα στρώματα των ινών ελεύθερα. [2][3][4][5] Η απόσταση των αγγείων από την υπεζωκοτική κοιλότητα είναι 10 -12 μm ενώ κυμαίνεται μεταξύ 18 -56 μm στον πνευμονικό. Η απόσταση αυτή αυξάνεται από τους άνω προς τους κάτω λοβούς γιατί και το πάχος του υπεζωκότα στους κάτω λοβούς είναι μεγαλύτερο.…”

Section: : τα δύο πέταλα του υπεζωκότα καλύπτονται από μια μονήρη στunclassified