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BackgroundIn patients with cirrhosis, the synthesis of coagulation factors can fall short, reflected by a prolonged prothrombin time. Although anticoagulants factors are decreased as well, blood loss during orthotopic liver transplantation can still be excessive. Blood loss during orthotopic liver transplantation is currently managed by transfusion of red blood cell concentrates, platelet concentrates, fresh frozen plasma, and fibrinogen concentrate. Transfusion of these products may paradoxically result in an increased bleeding tendency due to aggravated portal hypertension. The hemostatic effect of these products may therefore be overshadowed by bleeding complications due to volume overload.In contrast to these transfusion products, prothrombin complex concentrate is a low-volume highly purified concentrate, containing the four vitamin K dependent coagulation factors. Previous studies have suggested that administration of prothrombin complex concentrate is an effective method to normalize a prolonged prothrombin time in patients with liver cirrhosis. We aim to investigate whether the pre-operative administration of prothrombin complex concentrate in patients undergoing liver transplantation for end-stage liver cirrhosis, is a safe and effective method to reduce perioperative blood loss and transfusion requirements.Methods/DesignThis is a double blind, multicenter, placebo-controlled randomized trial.Cirrhotic patients with a prolonged INR (≥1.5) undergoing liver transplantation will be randomized between placebo or prothrombin complex concentrate administration prior to surgery. Demographic, surgical and transfusion data will be recorded. The primary outcome of this study is RBC transfusion requirements.DiscussionPatients with advanced cirrhosis have reduced plasma levels of both pro- and anticoagulant coagulation proteins. Prothrombin complex concentrate is a low-volume plasma product that contains both procoagulant and anticoagulant proteins and transfusion will not affect the volume status prior to the surgical procedure. We hypothesize that administration of prothrombin complex concentrate will result in a reduction of perioperative blood loss and transfusion requirements. Theoretically, the administration of prothrombin complex concentrate may be associated with a higher risk of thromboembolic complications. Therefore, thromboembolic complications are an important secondary endpoint and the occurrence of this type of complication will be closely monitored during the study.Trial registrationThe trial is registered at http://www.trialregister.nl with number NTR3174. This registry is accepted by the ICMJE.

Summary.  Background: Blood outgrowth endothelial cells (BOEC) are good candidates for vascular (re‐) generating cell therapy. Although cord blood (CB) BOEC have been reported as more proliferative than peripheral blood (PB) BOEC, not much is known about their functional properties. Objectives: We have studied the following determinants in BOEC expanded from CB and PB: endothelial phenotype, in vitro adhesion, migration, proliferation, and angiogenic tube forming capacity. Methods/Results: Endothelial phenotype of BOEC was evaluated by fluorescence activated cell sorting (FACS) analysis and confirmed the presence of endothelial markers including CD31, CD105, CD144, CD146, KDR/VEGFR‐2, Tie‐2, and TNF‐α‐induced VCAM‐1 and ICAM‐1. Evaluation of cell proliferation revealed a higher basal proliferation of CB‐BOEC, which increased after exposure to bFGF but not VEGF. The lower basal proliferation of PB‐BOEC increased with VEGF or bFGF addition. Array analysis of angiogenic genes showed many comparable expressions in both BOEC, and a slightly more pronounced pro‐angiogenic profile in CB‐BOEC than PB‐BOEC. Both BOEC were able to form tubular structures in a three‐dimensional fibrin matrix. Tube formation in CB‐BOEC was markedly induced by TNF‐α only and inhibited by anti‐urokinase antibodies. It was comparable to that induced by combined addition of TNF‐α and VEGF or bFGF, while maximal tube formation in PB‐BOEC required simultaneous exposure to TNF‐α/VEGF or TNF‐α/bFGF. Conclusions: The endothelial phenotype and characteristics for homing, adhesion, migration, inflammation, and angiogenic tube formation are almost equal for BOEC from CB and PB. A slightly more angiogenic phenotype favors CB‐BOEC. However, addition of VEGF to PB‐BOEC induces equal proliferation and tube formation.

The number of colony forming unit-endothelial cells (CFU-EC) in human peripheral blood was found to be a biological marker for several vascular diseases. In this study, the heterogeneous composition of immune cells in the CFU-ECs was investigated. We confirmed that monocytes are essential for the formation of CFU-ECs. Also, however, CD4+ T cells were found to be indispensable for the induction of CFU-EC colonies, mainly through cell-cell contact. By blocking or activating CD3 receptors on CD4+ T cells or blocking MHC class II molecules on monocytes, it was shown that TCR-MHCII interactions are required for induction of CFU-EC colonies. Because the supernatant from preactivated T cells could also induce colony formation from purified monocytes, the T cell support turned out to be cytokine mediated. Gene expression analysis of the endothelial-like colonies formed by CD14+ cells showed that colony formation is a proangiogenic differentiation and might reflect the ability of monocytes to facilitate vascularization. This in vitro study is the first to reveal the role of TCR-MHC class II interactions between T cells and monocytes and the subsequent inflammatory response as stimulus of monocytic properties that are associated with vascularization.

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These results show a beneficial role for T-cell-pre-stimulated monocytes in neovascularisation, rendering the monocyte a potential candidate for regenerative cell therapy that promotes revascularisation in peripheral arterial disease patients.

BackgroundIt is widely accepted that atherosclerosis and inflammation are intimately linked. Monocytes play a key role in both of these processes and we hypothesized that activation of inflammatory pathways in monocytes would lead to, among others, proatherogenic changes in the monocyte transcriptome. Such differentially expressed genes in circulating monocytes would be strong candidates for further investigation in disease association studies.MethodsEndotoxin, lipopolysaccharide (LPS), or saline control was infused in healthy volunteers. Monocyte RNA was isolated, processed and hybridized to Hver 2.1.1 spotted cDNA microarrays. Differential expression of key genes was confirmed by RT-PCR and results were compared to in vitro data obtained by our group to identify candidate genes.ResultsAll subjects who received LPS experienced the anticipated clinical response indicating successful stimulation. One hour after LPS infusion, 11 genes were identified as being differentially expressed; 1 down regulated and 10 up regulated. Four hours after LPS infusion, 28 genes were identified as being differentially expressed; 3 being down regulated and 25 up regulated. No genes were significantly differentially expressed following saline infusion. Comparison with results obtained in in vitro experiments lead to the identification of 6 strong candidate genes (BATF, BID, C3aR1, IL1RN, SEC61B and SLC43A3)ConclusionIn vivo endotoxin exposure of healthy individuals resulted in the identification of several candidate genes through which systemic inflammation links to atherosclerosis.