Comparison of Hepatic-like Cell Production from Human Embryonic Stem Cells and Adult Liver Progenitor Cells: CAR Transduction Activates a Battery of Detoxification Genes

In vitro production of human hepatocytes is of primary importance in basic research, pharmacotoxicology and biotherapy of liver diseases. We have developed a protocol of differentiation of human embryonic stem cells (ES) towards hepatocyte-like cells (ES-Hep). Using a set of human adult markers including CAAT/enhancer binding protein (C/EBPalpha), hepatocyte nuclear factor 4/7 ratio (HNF4alpha1/HNF4alpha7), cytochrome P450 7A1 (CYP7A1), CYP3A4 and constitutive androstane receptor (CAR), and fetal markers including alpha-fetoprotein, CYP3A7 and glutathione S-transferase P1, we analyzed the expression of a panel of 41 genes in ES-Hep comparatively with human adult primary hepatocytes, adult and fetal liver. The data revealed that after 21 days of differentiation, ES-Hep are representative of fetal hepatocytes at less than 20 weeks of gestation. The glucocorticoid receptor pathway was functional in ES-Hep. Extending protocols of differentiation to 4 weeks did not improve cell maturation. When compared with hepatocyte-like cells derived from adult liver non parenchymal epithelial (NPE) cells (NPE-Hep), ES-Hep expressed several adult and fetal liver makers at much greater levels (at least one order of magnitude), consistent with greater expression of liver-enriched transcription factors Forkhead box A2, C/EBPalpha, HNF4alpha and HNF6. It therefore seems that ES-Hep reach a better level of differentiation than NPE-Hep and that these cells use different lineage pathways towards the hepatic phenotype. Finally we showed that lentivirus-mediated expression of xenoreceptor CAR in ES-Hep induced the expression of several detoxification genes including CYP2B6, CYP2C9, CYP3A4, UDP-glycosyltransferase 1A1, solute carriers 21A6, as well as biotransformation of midazolam, a CYP3A4-specific substrate

Evaluation of downsized homograft conduits for right ventricle-to-pulmonary artery reconstruction

Objective: Although homograft conduits are frequently used to establish right ventricle-to-pulmonary artery continuity, the limited availability of small-size homografts is a significant constraint in pediatric cardiac surgery. We compared the performance of standard homograft conduits with that of surgically reduced bicuspid homograft conduits in patients undergoing repair of truncus arteriosus. Methods: Forty infants undergoing complete repair of truncus arteriosus with either standard homografts (n = 26) or reduced-size bicuspid homografts (n = 14) were evaluated. Results: The median downsized conduit diameter (13 mm) was similar to the standard homograft diameter (12 mm, P = .52). There were 6 early deaths and 5 late deaths, representing an overall 30-day mortality of 15% and a 5-year mortality of 25%. No deaths were directly related to homograft dysfunction. Four (29%) downsized conduits and 8 (31%) standard conduits required replacement at a median interval of 18.5 months and 42.4 months, respectively. Catheter-based interventions were required in 5 (36%) patients in the downsized group and in 3 (12%) patients in the standard group. There was no difference in freedom from surgical or catheter-based reintervention between the 2 groups (P = .42). Freedom from conduit failure (severe conduit stenosis, moderate or greater regurgitation) was 55.9% and 17.2% at 3 years in the downsized and standard groups, respectively. Conclusion: The surgically downsized homograft is an excellent option when an appropriate-sized homograft is not available and might prevent morbidity associated with the use of an oversized conduit

Cardiac magnetic resonance imaging prior to bidirectional cavopulmonary connection in hypoplastic left heart syndrome.

BACKGROUND: Recent evidence has suggested that haemodynamic information obtained from cardiac catheterisation is not essential in pre-operative assessment of children with hypoplastic left heart syndrome (HLHS) undergoing Bidirectional Cavopulmonary Connection (BCPC). Therefore our unit changed to cardiac Magnetic Resonance Imaging (MRI) in 2006. We aimed to compare peri-operative outcomes before and after this change. METHODS: Children with HLHS who underwent BCPC between 2004 and 2008 were identified. Data were collected regarding pre-operative findings and peri-operative outcomes. RESULTS: Forty patients were identified-catheterisation (n=21), MRI (n=19). Catheterisation patients were older at the time of BCPC (114.9+/-22.7 days vs. 95.4+/-11 days: p value 0.002), with no other differences in baseline data. Two patients required cardiopulmonary resuscitation during catheterisation; with no adverse events during MRI. Cardiopulmonary bypass time, ventilation time, inotrope score, and intensive care unit stay were similar. Length of hospital stay and oxygen saturations at discharge were also not significantly different. CONCLUSIONS: We have demonstrated that post-operative course and outcomes are similar in patients with HLHS who had MRI or catheterisation as their pre-BCPC investigation. Additionally the complementary data provided by echocardiography and MRI safely provides sufficient anatomic and functional information with which to plan the BCPC

Ross Procedure in Children: 17-Year Experience at a Single Institution

BACKGROUND: The Ross procedure in children carries substantial mortality and reoperation rate. Aortic root dilatation is of concern. To prevent dilatation of the neoaortic root, but permit normal growth, we began to apply an absorbable poly-(p-dioxanone)-filaments (PDS) band at the sino-tubular (ST)-junction. METHODS AND RESULTS: All children (n=100) who underwent Ross procedure during 1995-2012 were studied. Mean age at operation was 8.6±6.1 years (median 8.3 years, range 3 days to 18 years); 19 patients were younger than 1 year of age. The root replacement (n=91, Ross-Konno procedure in 29 patients), root inclusion (n=6), and subcoronary implantation (n=3) techniques were used. Operative mortality was 6% (6/100, 4 neonates, 2 infants). Age of 4 was greatest at the ST-junction (23%, 11/48) compared to the aortic annulus (17%, 11/66) and sinuses (14%, 7/50). Since 2001, a PDS band was placed around the ST-junction in 19 patients. Survivors with the PDS band had less AI (0 versus 20%, P=0.043) compared to survivors (n=35) without the PDS at 4.1±3 years. CONCLUSIONS: The Ross procedure in children can be performed with acceptable results. Children younger than 1 year of age have higher mortality, but not an increased autograft reoperation rate. Stabilization of the ST-junction may reduce AI

Remote ischemic preconditioning in cyanosed neonates undergoing cardiopulmonary bypass: a randomized controlled trial.

OBJECTIVE: The myocardial protective effect of remote ischemic preconditioning has been demonstrated in heterogeneous groups of patients undergoing cardiac surgery. No studies have examined this technique in neonates. The present study was performed to examine the remote ischemic preconditioning efficacy in this high-risk patient group. METHODS: A preliminary, randomized, controlled trial was conducted to investigate whether remote ischemic preconditioning in cyanosed neonates undergoing cardiac surgery confers protection against cardiopulmonary bypass. Two groups of neonates undergoing cardiac surgery were recruited for the present study: patients with transposition of the great arteries undergoing the arterial switch procedure and patients with hypoplastic left heart syndrome undergoing the Norwood procedure. The subjects were randomized to the remote ischemic preconditioning or sham control groups. Remote ischemic preconditioning was induced by four 5-minute cycles of lower limb ischemia and reperfusion using a blood pressure cuff. Troponin I and the biomarkers for renal and cerebral injury were measured pre- and postoperatively. RESULTS: A total of 39 neonates were recruited-20 with transposition of the great arteries and 19 with hypoplastic left heart syndrome. Of the 39 neonates, 20 were randomized to remote ischemic preconditioning and 19 to the sham control group. The baseline demographics appeared similar between the randomized groups. The cardiopulmonary bypass and crossclamp times were not significantly different between the 2 groups. The troponin I levels were not significantly different at 6 hours after cardiopulmonary bypass nor were the postoperative inotrope requirements. Markers of renal (neutrophil gelatinase-associated lipocalin) and cerebral injury (S100b, neuron-specific enolase) were not significantly different between the 2 groups. CONCLUSIONS: Our data suggest that remote ischemic preconditioning in hypoxic neonates undergoing cardiopulmonary bypass surgery does not provide myocardial, renal, or neuronal protection. Additional studies are needed to examine the relationships among developmental age, hypoxia, and the molecular mechanisms of ischemic preconditioning