lactoferrin and Ischemia

Lactoferrin (LF) exerts a variety of biological effects, including the promotion of angiogenesis by increasing the expression of angiogenesis-related genes and reducing blood pressure via a nitric oxide-dependent mechanism. In this study, we investigated the effects of LF on angiogenesis using C57BL/6J mice that received daily unilateral treatment with or without bovine milk-derived LF (bLF) after unilateral hindlimb surgery. The analysis of laser speckle blood flow showed that bLF treatment promoted blood flow recovery in response to ischemic hindlimb. The capillary density of ischemic adductor muscles and the phosphorylation of Src, Akt, and endothelial nitric oxide synthase (eNOS) were also significantly higher in bLF-treated mice than in vehicle-treated mice. Furthermore, bLF increased the phosphorylation levels of Src, Akt, and eNOS in in vitro experiments using human aortic endothelial cells. The action of bLF on eNOS phosphorylation was abolished by both LY294002, a phosphatidylinositol 3-kinase inhibitor, and 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo [3,4-d]pyrimidine (PP2), an Src inhibitor. Similarly, bLF-induced acceleration of tube formation, cell proliferation, and cell migration in human aortic endothelial cells were inhibited by LY294002 or PP2. Thus, bLF promotes vascular endothelial cell function via an Src Akt eNOS-dependent pathway, thereby contributing to revascularization in response to ischemia.

Topics: Animals; Aorta; Cell Movement; Cell Proliferation; Cells, Cultured; Endothelial Cells; Endothelium, Vascular; Enzyme Activation; Hindlimb; Humans; In Vitro Techniques; Ischemia; Lactoferrin; Laser-Doppler Flowmetry; Mice; Mice, Inbred C57BL; Milk; Neovascularization, Physiologic; Nitric Oxide Synthase Type III; Phosphorylation; Proto-Oncogene Proteins c-akt; Reperfusion Injury; Signal Transduction; src-Family Kinases

Experimental models of hepatic ischemia/reperfusion injury have implicated a pathophysiologic role for neutrophils in subsequent hepatocellular damage. In human liver transplantation, however, the effect of reperfusion-induced neutrophil activation on initial graft function is not clear.. In 38 patients undergoing liver transplantation, neutrophil CD11b and L-selectin expression, neutrophil count, and plasma lactoferrin levels were measured. To assess changes within the graft during initial reperfusion, samples of blood entering and leaving the graft were obtained simultaneously, and transhepatic ratio calculated (hepatic vein/portal vein; 1 denotes no change, <1 a decrease, and >1 an increase across the liver). Graft steatosis, postoperative liver function, and outcome were recorded. Associations between neutrophil activation markers and outcome measures were evaluated.. Substantial hepatic neutrophil activation occurred during initial reperfusion, demonstrated by concomitant L-selectin shedding and CD11b upregulation (transhepatic ratios 0.9 [0.7-1.0]; 1.4 [0.9-1.9]; both P < .001; portal vs hepatic vein]. Simultaneously, hepatic neutrophil sequestration and lactoferrin release occurred (0.3 [0.2-0.5]; 1.7 [1.3-3.4]; both P < .001). Neither cold ischemic time (CIT; median 5 hours 36 minutes) nor hepatic neutrophil activation during reperfusion predicted early graft function, nor was there any association between CIT and neutrophil activation.. Despite short CIT, extensive graft neutrophil activation and sequestration occurred. This, however, was not associated with impaired early graft function, suggesting short CIT may protect against severe neutrophil-mediated injury.

Topics: Adult; Antigens, CD; CD11b Antigen; Female; Graft Rejection; Graft Survival; Hepatic Veins; Humans; Ischemia; L-Selectin; Lactoferrin; Leukocyte Count; Liver Diseases; Liver Transplantation; Male; Middle Aged; Neutrophil Activation; Portal Vein; Reperfusion; Survival Analysis; Survivors; Young Adult

In this study, we hypothesized that the lung actively releases excess iron into the circulation to regulate iron homeostasis. We measured nonheme iron (NHFe) in the perfusate of control isolated perfused rabbit lungs and lungs with ischemia-reperfusion (I/R) ventilated with normoxic (21% O(2)) or hypoxic (95% N(2)) gas mixtures. Some were perfused with bicarbonate-free (HEPES) buffer or treated with the anion exchange inhibitor DIDS. The control lungs released approximately 0.25 microg/ml of NHFe or 20% of the total lung NHFe into the vascular space that was not complexed with ferritin, transferrin, or lactoferrin or bleomycin reactive. The I/R lungs released a similar amount of NHFe during ischemia and some bleomycin-detectable iron during reperfusion. NHFe release was attenuated by approximately 50% in both control and ischemic lungs by hypoxia and by >90% in control lungs and approximately 60% in ischemic lungs by DIDS and HEPES. Reperfusion injury was not affected by DIDS or HEPES but was attenuated by hypoxia. These results indicate that biologically nonreactive nonheme iron is released rapidly by the lung into the vascular space via mechanisms that are linked to bicarbonate exchange. During prolonged ischemia, redox-active iron is also released into the vascular compartment by other mechanisms and may contribute to lung injury.

Topics: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; Animals; Anion Exchange Protein 1, Erythrocyte; Bicarbonates; Bleomycin; Ferritins; Hypoxia; In Vitro Techniques; Iron; Ischemia; Lactoferrin; Lung; Male; Perfusion; Pulmonary Circulation; Rabbits; Reperfusion Injury; Transferrin