Bradykinin and tumor necrosis factor-α alter albumin transport in vivo : A comparative study

• Published in: Microvascular research 1997-11, Vol.54 (3), p.221-232
• Main Authors: SAULPAW, C. E, JOYNER, W. L
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Biological Transport - drug effects; Blood vessels and receptors; Bradykinin - pharmacology; Capillary Permeability - drug effects; Cricetinae; Dose-Response Relationship, Drug; Fundamental and applied biological sciences. Psychology; Male; Mesentery; Mesocricetus; Serum Albumin - metabolism; Time Factors; Tumor Necrosis Factor-alpha - pharmacology; Venous Pressure - drug effects; Vertebrates: cardiovascular system
• ISSN: 0026-2862; 1095-9319
• DOI: 10.1006/mvre.1997.2041

These studies indicate that tumor necrosis factor-alpha (TNF alpha) alters albumin permeability and unlike bradykinin (BK) the increased albumin permeability lasts for the duration of the application. Neither agonist requires the presence of white blood cells or other blood-borne substances to produce this inflammatory response. These experiments were completed in the in situ, microcannulated, perfused venules of the mesentery in the anesthetized hamster. Albumin transport was measured using intravital fluorescence microscopy, TRITC-labeled albumin, and densitometric tracking. Further, by varying the intravascular pressure, the hydraulic (Lp(1 sigma)) and diffusive permeability (P0) coefficients of these microvessels were determined. Both BK and TNF alpha produced an increase in albumin flux, which was dependent upon the dose and time domains. This response was present when the agonists were given by either intra- or extravascular presentation. Both hydraulic coupling and microvascular permeability were increased by BK and TNF alpha. TNF alpha increased albumin permeability rapidly and its effect lasted as long as TNF alpha was present, whereas the increased albumin transport by BK was biphasic. The results implicate a dynamic modification in the microvascular wall to these inflammatory agonists and the mechanism(s) for transduction in the endothelium are quite different.