Porcine aortic endothelial cell genes responsive to selected inflammatory stimulators

Effect of TNF-alpha blockade on coagulopathy and endothelial cell activation in xenoperfused porcine kidneys

BACKGROUND

Following pig-to-primate kidney transplantation, endothelial cell activation and xenogenic activation of the recipient's coagulation eventually leading to organ dysfunction and microthrombosis can be observed. In this study, we examined the effect of a TNF-receptor fusion protein (TNF-RFP) on endothelial cell activation and coagulopathy utilizing an appropriate ex vivo perfusion system.

METHODS

Using an ex vivo perfusion circuit based on C1-Inhibitor (C1-Inh) and low-dose heparin administration, we have analyzed consumptive coagulopathy following contact of human blood with porcine endothelium. Porcine kidneys were recovered following in situ cold perfusion with Histidine-tryptophan-ketoglutarate (HTK) organ preservation solution and were immediately connected to a perfusion circuit utilizing freshly drawn pooled porcine or human AB blood. The experiments were performed in three individual groups: autologous perfusion (n = 5), xenogenic perfusion without any further pharmacological intervention (n = 10), or with addition of TNF-RFP (n = 5). After perfusion, tissue samples were obtained for real-time PCR and immunohistological analyses. Endothelial cell activation was assessed by measuring the expression levels of E-selectin, ICAM-1, and VCAM-1.

RESULTS

Kidney survival during organ perfusion with human blood, C1-Inh, and heparin, but without any further pharmacological intervention was 126 ± 78 min. Coagulopathy was observed with significantly elevated concentrations of D-dimer and thrombin-antithrombin complex (TAT), resulting in the formation of multiple microthrombi. Endothelial cell activation was pronounced, as shown by increased expression of E-selectin and VCAM-1. In contrast, pharmacological intervention with TNF-RFP prolonged organ survival to 240 ± 0 min (max. perfusion time; no difference to autologous control). Formation of microthrombi was slightly reduced, although not significantly, if compared to the xenogenic control. D-dimer and TAT were elevated at similar levels to the xenogenic control experiments. In contrast, endothelial cell activation, as shown by real-time PCR, was significantly reduced in the TNF-RFP group.

CONCLUSION

We conclude that although coagulopathy was not affected, TNF-RFP is able to suppress inflammation occurring after xenoperfusion in this ex vivo perfusion model.

Changes in gene expression of pial vessels of the blood brain barrier during murine neurocysticercosis

In murine neurocysticercosis (NCC), caused by infection with the parasite Mesocestoides corti, the breakdown of the Blood Brain Barrier (BBB) and associated leukocyte infiltration into the CNS is dependent on the anatomical location and type of vascular bed. Prior studies of NCC show that the BBB comprised of pial vessels are most affected in comparison to the BBB associated with the vasculature of other compartments, particularly parenchymal vessels. Herein, we describe a comprehensive study to characterize infection-induced changes in the genome wide gene expression of pial vessels using laser capture microdissection microscopy (LCM) combined with microarray analyses. Of the 380 genes that were found to be affected, 285 were upregulated and 95 were downregulated. Ingenuity Pathway Analysis (IPA) software was then used to assess the biological significance of differentially expressed genes. The most significantly affected networks of genes were “inflammatory response, cell-to-cell signaling and interaction, cellular movement”, “cellular movement, hematological system development and function, immune cell trafficking, and “antimicrobial response, cell-to-cell signaling and interaction embryonic development”. RT-PCR analyses validated the pattern of gene expression obtained from microarray analysis. In addition, chemokines CCL5 and CCL9 were confirmed at the protein level by immunofluorescence (IF) microscopy. Our data show altered gene expression related to immune and physiological functions and collectively provide insight into changes in BBB disruption and associated leukocyte infiltration during murine NCC.

Neurocysticercosis (NCC) is one of the most common parasitic diseases of the CNS caused by the metacestode (larva) of the tapeworm Taenia solium. Epidemiological studies show that among the various forms of NCC, subarachnoid NCC is associated with poor prognosis, more resistance to anti-helminthic drugs and more severe inflammation. The chronic inflammation of the vasculature and arachnoid thickening (chronic basal meningitis) leads to blockade of CSF further contributing to CNS pathology. Using a murine model for NCC, we have found that among the different types of vasculature associated with the blood-brain barrier (BBB), pial vessels of BBB are compromised earlier and to a greater extent during NCC. In addition, pial vessels are likely the most important entryway for leukocyte infiltration during NCC. The aim of this study was to characterize infection-induced changes in the genome-wide gene expression of pial vessels. Our approach was to isolate pial vessels of the BBB by in vivo labeling of vessels followed by laser capture microdissection microscopy (LCM). Further, microarray analysis of pial vessels showed infection-induced changes in the expression of genes associated with both immunity and disease, and collectively provides insight into the dysfunction of the BBB and mechanisms associated with leukocyte infiltration during murine NCC.