Human hepatic stem cells from fetal and postnatal donors

Human hepatic stem cells (hHpSCs), which are pluripotent precursors of hepatoblasts and thence of hepatocytic and biliary epithelia, are located in ductal plates in fetal livers and in Canals of Hering in adult livers. They can be isolated by immunoselection for epithelial cell adhesion molecule-positive (EpCAM+) cells, and they constitute approximately 0.5-2.5% of liver parenchyma of all donor ages. The self-renewal capacity of hHpSCs is indicated by phenotypic stability after expansion for >150 population doublings in a serum-free, defined medium and with a doubling time of approximately 36 h. Survival and proliferation of hHpSCs require paracrine signaling by hepatic stellate cells and/or angioblasts that coisolate with them. The hHpSCs are approximately 9 microm in diameter, express cytokeratins 8, 18, and 19, CD133/1, telomerase, CD44H, claudin 3, and albumin (weakly). They are negative for alpha-fetoprotein (AFP), intercellular adhesion molecule (ICAM) 1, and for markers of adult liver cells (cytochrome P450s), hemopoietic cells (CD45), and mesenchymal cells (vascular endothelial growth factor receptor and desmin). If transferred to STO feeders, hHpSCs give rise to hepatoblasts, which are recognizable by cordlike colony morphology and up-regulation of AFP, P4503A7, and ICAM1. Transplantation of freshly isolated EpCAM+ cells or of hHpSCs expanded in culture into NOD/SCID mice results in mature liver tissue expressing human-specific proteins. The hHpSCs are candidates for liver cell therapies.     

Vagus nerve stimulation: Outcome and predictors of seizure freedom in long-term follow-up

ObjectivesTo present long-term outcome and to identify predictors of seizure freedom after vagus nerve stimulation (VNS).MethodsAll patients who had undergone VNS implantation in the Epilepsy Centre Bethel were retrospectively reviewed. There were 144 patients who had undergone complete presurgical evaluation, including detailed clinical history, magnetic resonance imaging, and long-term video-EEG with ictal and interictal recordings. After implantation, all patients were examined at regular intervals of 4 weeks for 6–9 months. During this period the antiepileptic medication remained constant. All patients included in this study were followed up for a minimum of 2 years.ResultTen patients remained seizure-free for more than 1 year after VNS implantation (6.9%). Seizures improved in 89 patients (61.8%) but no changes were observed in 45 patients (31.3%). The following factors were significant in the univariate analysis: age at implantation, multifocal interictal epileptiform discharges, unilateral interictal epileptiform discharge, cortical dysgenesis, and psychomotor seizure. Stepwise multivariate analysis showed that unilateral interictal epileptiform discharges (IEDs), P = 0.014, HR = 0.112 (95% CIs, 0.019–0.642), cortical dysgenesis P = 0.007, HR = 0.065 (95% CIs, 0.009–0.481) and younger age at implantation P = 0.026, HR = 7.533 (95% CIs 1.28–44.50) were independent predictors of seizure freedom in the long-term follow-up.ConclusionVNS implantation may render patients with some forms of cortical dysgenesis (parietooccipital polymicrogyria, macrogyria) seizure-free. Patients with unilateral IEDs and earlier implantation achieved the most benefit from VNS.     

Hepatitis C infection, Cognition, and inflammation in an Egyptian sample

Chronic hepatitis C (HCV) infection is associated with cognitive impairments which might be mediated through a secondary inflammatory cascade. Egypt has an unusually high prevalence of HCV monoinfections and is an ideal site for the study of the isolated effects of HCV infection. Therefore, in a hospital‐based cross‐sectional study based in Egypt, this study compared cognitive functioning and serum markers of inflammation in 11 HCV positive cases and 14 HCV negative controls. The Wisconsin Card Sorting Test was used to assess cognitive flexibility and the Brief Visuospatial Memory Test‐Revised was used to assess learning and memory. Circulating levels of soluble tumor necrosis factor receptor II (sTNFR‐II), monocyte chemotactic protein‐1 (MCP‐1/CCL2), and soluble CD14 (sCD14) were determined as indices of inflammation. HCV positive cases had higher levels of sTNFR‐II (t = ?3.5, P = 0.002). HCV positive cases also had significantly worse cognitive flexibility with higher number of total errors (t = ?2.18, P = 0.04), and preservative responses (t = ?2.12, P = 0.05), and lower number of conceptual level responses (t = 1.32, P = 0.04) on the Wisconsin Card Sorting test. In conclusion, results from this pilot study indicate that HCV+ patients have worse cognitive performance and somewhat greater inflammatory activity as compared to controls. The increased inflammation may be associated with the cognitive impairments observed in these HCV+ patients. J. Med. Virol. 83:261–266, 2011. © 2010 Wiley‐Liss, Inc.     

Divergent roles of sphingosine kinases in kidney ischemia-reperfusion injury

Sphingosine-1-phosphate (S1P), produced by sphingosine kinase 1 (SphK1) or kinase 2 (SphK2), mediates biological effects through intracellular and/or extracellular mechanisms. Here we determined a role for these kinases in kidney injury of wild-type mice following ischemia-reperfusion. SphK1 but not SphK2 mRNA expression and activity increased in the kidney following injury relative to sham-operated animals. Although SphK1(-/-) mice had no alteration in renal function following injury, mice with a disrupted SphK2 gene (SphK2(tr/tr)) had histological damage and impaired function. The immune-modulating pro-drug, FTY720, an S1P agonist failed to provide protection in SphK2(tr/tr) mice. Injured kidneys of these mice showed increased neutrophil infiltration and neutrophil chemokine expression along with a 3- to 5-fold increase in expression of the G-protein-coupled receptor S1P(3) compared to heterozygous SphK2(+/tr) mice. Kidney function and reduced vascular permeability were preserved in S1P(3)(-/-) compared to S1P(3)(+/-) mice after ischemia-reperfusion injury, suggesting increased S1P(3) mRNA may play a role in the injury of SphK2(tr/tr) mice. Our study suggests that constitutive expression of SphK2 may contribute to reduced ischemia-reperfusion injury of the kidney, and its absence may enhance injury due to increased neutrophil infiltration and S1P(3) activation. We also confirm that SphK2 is necessary to mediate the protective effects of FTY720.     

Intercellular adhesion molecules in systemic lupus erythematosus patients with lupus nephritis

Cardiovascular events are markedly increased in systemic lupus erythematosus (SLE), and the mechanism of atherogenesis remains poorly understood. Several methods have been employed to assess endothelial function, among these is the measurement of biomarkers of endothelial activation and dysfunction [intercellular adhesion molecule (ICAM-1)]. It has been reported that such biomarkers play a more important role than traditional risk factors in cardiovascular disease. The objectives of this study were to determine the level of ICAM-1 as markers of endothelial dysfunction in 40 Egyptian patients who have SLE with various degrees of activity and to investigate their relationship to disease activity. Sixty people (40 with SLE and 20 healthy as the control group) were the subject of this study; their clinical disease activity was scored according to the SLE disease activity index (SLEDAI), and serum sampling was obtained for ICAM-1 level assay. Renal biopsy was carried out and examined by light microscopy by a pathologist blinded to the clinical activity. The mean level of ICAM-1 was significantly higher in SLE patients with active disease (826.05 ± 367.1 Pg/ml) compared to those with inactive disease (441.33 ± 225.19 Pg/ml) and the healthy control volunteers (111.5 ± 17.36 Pg/ml). There was a positive correlation between serum ICAM-1 and SLEDAI (r = 0.66). A high concentration of soluble ICAM-1 in SLE patients with nephritis is reported in this paper. Our finding of increased concentrations of ICAM-1 in SLE patients with nephritis underlines the importance of inflammation and endothelial involvement in this disease, but their predictive value in the disease monitoring need to be further studied.