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- Reed, Rolf K., et al.
(författare)
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Transcapillary exchange : role and importance of the interstitial fluid pressure and the extracellular matrix
- 2010
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Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 87:2, s. 211-217
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Forskningsöversikt (refereegranskat)abstract
- This review will summarize current knowledge on the role of the extracellular matrix (ECM) in general and on the interstitial fluid pressure (P-if) in particular with regard to their importance in transcapillary exchange. The fluid volume in the interstitial space is normally regulated within narrow limits by automatic re-adjustment of the interstitial hydrostatic and colloid osmotic pressures in response to perturbations in capillary filtration and by the lymphatics. Contrary to this commonly accepted view, P-if can become an active force and create a fluid flux across the capillaries in several inflammatory reactions and trauma situations rather than limit the changes occurring. The molecular mechanisms involved in the lowering of P-if include the release of cellular tension exerted on the collagen and microfibril networks in the connective tissue via the collagen-binding beta(1)-integrins, thereby allowing the glycosaminoglycan ground substance, which is normally underhydrated, to expand and take up fluid. Several growth factors and cytokines, including the platelet-derived growth factor BB, are able to reverse a lowering of P-if and restore the normal compaction of the ECM. The magnitude of the lowering of P-if varies with the inflammatory response. In several inflammatory reactions, a lowering of P-if to -5 to -10 mmHg is seen, which will increase capillary filtration by 10-20 times since the normal capillary filtration pressure is usually 0.5-1 mmHg (skin and skeletal muscle). Unless this lowering of P-if is taken into account, the enhanced solute flux resulting from an inflammatory response will be ascribed to an increased capillary permeability.
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