Wiebke Baars

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BACKGROUND The major immunological hurdle to successful porcine-to-human xenotransplantation is the acute vascular rejection (AVR), characterized by endothelial cell (EC) activation and perturbation of coagulation. Heme oxygenase-1 (HO-1) and its derivatives have anti-apoptotic, anti-inflammatory effects and protect against reactive oxygen species,(More)
Acute vascular rejection (AVR), in particular microvascular thrombosis, is an important barrier to successful pig-to-primate xenotransplantation. Here, we report the generation of pigs with decreased tissue factor (TF) levels induced by small interfering (si)RNA-mediated gene silencing. Porcine fibroblasts were transfected with TF-targeting small hairpin(More)
The 77C-->G mutation in exon A of the human CD45 gene occurs with low frequency in healthy individuals. An enhanced frequency of 77C-->G individuals has been reported in cohorts of patients suffering from multiple sclerosis, systemic sclerosis, autoimmune hepatitis, and HIV-1. To investigate the mechanisms by which the variant allele may contribute to(More)
BACKGROUND Among other mismatches between human and pig, incompatibilities in the blood coagulation systems hamper the xenotransplantation of vascularized organs. The provision of the porcine endothelium with human thrombomodulin (hTM) is hypothesized to overcome the impaired activation of protein C by a heterodimer consisting of human thrombin and porcine(More)
Xenotransplantation from pigs could alleviate the shortage of human tissues and organs for transplantation. Means have been identified to overcome hyperacute rejection and acute vascular rejection mechanisms mounted by the recipient. The challenge is to combine multiple genetic modifications to enable normal animal breeding and meet the demand for(More)
BACKGROUND Genetic modification of pigs (e.g., transgenic expression of human complement regulatory molecules or inactivation of alpha1,3galactosyltransferase) enabled the development of promising strategies to overcome hyperacute rejection after pig-to-primate xenotransplantation. However, cellular rejection still remains a hurdle for successful xenograft(More)
UNLABELLED Multiple modifications of the porcine genome are required to prevent rejection after pig-to-primate xenotransplantation. Here, we produced pigs with a knockout of the α1,3-galactosyltransferase gene (GGTA1-KO) combined with transgenic expression of the human anti-apoptotic/anti-inflammatory molecules heme oxygenase-1 and A20, and investigated(More)
BACKGROUND Efficient and precise techniques for the genetic modification of pigs facilitate the generation of tailored donor animals for xenotransplantation. Numerous transgenic pig lines exist with the focus on inhibition of the complement system and of humoral immune responses. In addition, immune cell-based responses need to be controlled to prevent(More)
Cellular rejection is a relevant hurdle for successful pig-to-primate xenotransplantation. We have shown previously that the induction of a human anti-pig T cell response (in vitro activation of CD4(+) T cells) can be suppressed by the overexpression of human negative costimulatory ligands (e.g. programmed death receptor ligand, PD-L1) on pig antigen(More)