Microarray-based transcriptional profiling of Eimeria bovis-infected bovine endothelial host cells

Within its life cycle Eimeria bovis undergoes a long lasting intracellular development into large macromeronts in endothelial cells. Since little is known about the molecular basis of E. bovis-triggered host cell regulation we applied a microarray-based approach to define transcript variation in bovine endothelial cells early after sporozoite invasion (4 h post inoculation (p.i.)), during trophozoite establishment (4 days p.i.), during early parasite proliferation (8 days p.i.) and towards macromeront maturation (14 days p.i.). E. bovis infection led to significant changes in the abundance of many host cell gene transcripts. As infection progressed, the number of regulated genes increased such that 12, 45, 175 and 1184 sequences were modulated at 4 h, 4, 8 and 14 days p.i., respectively. These genes significantly interfered with several host cell functions, networks and canonical pathways, especially those involved in cellular development, cell cycle, cell death, immune response and metabolism. The correlation between stage of infection and the number of regulated genes involved in different aspects of metabolism suggest parasite-derived exploitation of host cell nutrients. The modulation of genes involved in cell cycle arrest and host cell apoptosis corresponds to morphological in vitro findings and underline the importance of these aspects for parasite survival. Nevertheless, the increasing numbers of modulated transcripts associated with immune responses also demonstrate the defensive capacity of the endothelial host cell. Overall, this work reveals a panel of novel candidate genes involved in E. bovis-triggered host cell modulation, providing a valuable tool for future work on this topic

Inhibition of host cell apoptosis by Eimeria bovis sporozoites

Sophisticated evasion strategies of obligate intracellular parasites, in particular prevention of host cell apoptosis, are necessary to ensure successful replication. To study the ability of Eimeria bovis in this regard, in vitro experiments were performed applying bovine foetal gastrointestinal cells (BFGC), bovine umbilical vein endothelial cells (BUVEC) and African green monkey kidney cells (VERO) as host cells. BUVEC and BFGC allow maturation of sporozoites to macromeronts, in VERO cells sporozoites survive for weeks without showing further development. In highly infected BUVEC monolayers, infected cells survived until merozoite release whereas uninfected cells underwent apoptosis. Light microscopy and TUNEL assays performed 3-10 days p.i. showed that, within infected BFGC and VERO cell monolayers, uninfected cells underwent programmed cell death after application of various inducers of apoptosis, whereas infected cells survived. Incidentally, the anti-apoptotic efficacies in infected cells were independent of the drugs and the host cell type. We could not demonstrate significant differences between infected and uninfected cells after colchicin treatment in terms of translation of phosphaticlylserines to the host cell surface, caspase 3 activity and cytochrome c release, probably since obtainable infection rates were too low. However, we could show by laser scanning confocal microscopy on single cell levels that the expression of the anti-apoptotic factors cellular Flice inhibitory protein (c-FLIP) and cellular inhibition of apoptosis protein 1 (c-IAP1) were enhanced in E. bovis infected cells after application of colchicin, in the latter case also in non-infected cells directly neighbouring infected ones. Our data show that E. bovis protects its host cell from apoptosis by increasing expression of c-IAP1 and c-FLIP. (C) 2008 Elsevier B.V. All rights reserved

Volume reduction of the jugular foramina in Cavalier King Charles Spaniels with syringomyelia

<p>Abstract</p> <p>Background</p> <p>Understanding the pathogenesis of the chiari-like malformation in the Cavalier King Charles Spaniel (CKCS) is incomplete, and current hypotheses do not fully explain the development of syringomyelia (SM) in the spinal cords of affected dogs. This study investigates an unconventional pathogenetic theory for the development of cerebrospinal fluid (CSF) pressure waves in the subarachnoid space in CKCS with SM, by analogy with human diseases. In children with achondroplasia the shortening of the skull base can lead to a narrowing of the jugular foramina (JF) between the cranial base synchondroses. This in turn has been reported to cause a congestion of the major venous outflow tracts of the skull and consequently to an increase in the intracranial pressure (ICP). Amongst brachycephalic dog breeds the CKCS has been identified as having an extremely short and wide braincase. A stenosis of the JF and a consequential vascular compromise in this opening could contribute to venous hypertension, raising ICP and causing CSF jets in the spinal subarachnoid space of the CKCS. In this study, JF volumes in CKCSs with and without SM were compared to assess a possible role of this pathologic mechanism in the development of SM in this breed.</p> <p>Results</p> <p>Computed tomography (CT) scans of 40 CKCSs > 4 years of age were used to create three-dimensional (3D) models of the skull and the JF. Weight matched groups (7–10 kg) of 20 CKCSs with SM and 20 CKCSs without SM were compared. CKCSs without SM presented significantly larger JF -volumes (median left JF: 0.0633 cm³; median right JF: 0.0703 cm³; p < 0.0001) when compared with CKCSs with SM (median left JF: 0.0382 cm³; median right JF: 0.0434 cm³; p < 0.0001). There was no significant difference between the left and right JF within each group. Bland-Altman analysis revealed excellent reproducibility of all volume measurements.</p> <p>Conclusion</p> <p>A stenosis of the JF and consecutive venous congestion may explain the aetiology of CSF pressure waves in the subarachnoid space, independent of cerebellar herniation, as an additional pathogenetic factor for the development of SM in this breed.</p

Lungworm infections (Angiostrongylus vasorum, Crenosoma vulpis, Aelurostrongylus abstrusus) in dogs and cats in Germany and Denmark in 2003-2007

Faecal samples of 4151 dogs from Denmark, 958 clogs from Germany and 231 cats from Germany with clinical signs were examined for lungworm larvae using the Baermann funnel technique between 2003 and 2007. In total, 3.6% of Danish and German dogs shed lungworm larvae. In Denmark, patent infections of clogs with Angiostrongylus vasorum were more prevalent (2.2%) than those with Crenosoma vulpis (1.4%). In Denmark, the majority of A. vasorum- (98%) and C. vulpis-infected (80%) clogs originated from Northern Zealand. The frequency of A. vasorum and C. vulpis infections in Danish dogs obviously decreased from 2003 to 2006. In Germany, canine faecal samples were found more frequently positive for C. vulpis than for A. vasorum larvae (2.4% and 1.2%, respectively). Lungworm-infected dogs originated mainly from Southern and western Germany. Larvae of Aelurostrongylus abstrusus were detected in 5.6% of cats from Germany. Overall, a distinct seasonal pattern in the detection of infected dogs was apparent for A. vasorum in Denmark and C. vulpis in Germany. The relatively high number of lungworm-infected dogs and cats indicate that these parasitic diseases should be considered in differential diagnosis of cases of treatment-resistant respiratory/cardiopulmonary distress. (C) 2008 Elsevier B.V. All rights reserved