Effects of lactoferrin on rat dermal interstitial fluid pressure (Pif) and in vitro endothelial barrier function.
We recently demonstrated that intravenous (i.v.) injection of the iron-binding protein lactoferrin (Lf) followed by antilactoferrin (aLf) antibodies or iron-saturated Lf alone increased albumin extravasation in vivo in several tissues including skin. Increased driving pressure for blood-tissue exchange or direct effects of Lf on the endothelial barrier are possible mechanisms. We therefore, firstly, measured interstitial fluid pressure (Pif) in dermis of rats given 1 mg Lf i.v. followed 30 min later by aLf or saline and circulatory arrest 1 or 5 min thereafter and compared with controls. Secondly, transmonolayer passage of Evans blue labelled albumin (EB-albumin) was evaluated in porcine pulmonary artery endothelial cells exposed to iron-free or iron-saturated Lf (both 100 microg mL-1) in the absence and presence of 0.5 mM hydrogen peroxide. Pif increased significantly at 11-30 min following Lf to +2.1 +/- 0.3 and +1.7 +/- 0.2 mmHg at 11-20 and 21-30 min, respectively, compared with +0.1 +/- 0.2 mmHg before Lf (P < 0.05, n=25). Endothelial transmonolayer passage of EB-albumin during 3 h was not affected by iron-free or iron-saturated Lf neither in the absence nor presence of hydrogen peroxide that increased passage 3.5 times compared with controls. In conclusion, Lf-induced increase in albumin extravasation in rat skin is not explained by changes in Pif (because Lf raised Pif significantly) or direct effects of Lf on the endothelial barrier.
Erga
K S
KS
Department of Physiology, University of Bergen, Bergen, Norway.
Peen
E
E
Enestrøm
S
S
Reed
R K
RK
D000418:Albumins / Q000378:metabolism; D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D020405:Dermis / Q000187:drug effects* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D005070:Evans Blue / Q000378:metabolism; D005110:Extracellular Space / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006614:Hindlimb / Q000187:drug effects / Q000502:physiology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007275:Injections, Intravenous; D007781:Lactoferrin / Q000008:administration & dosage / Q000276:immunology / Q000494:pharmacology*; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D013552:Swine
D000418:Albumins; D005070:Evans Blue; D006861:Hydrogen Peroxide; D007781:Lactoferrin