In vivo retrovirus-mediated gene transfer into lamb liver.

TOPIC: Highly efficient retrovirus-mediated gene transfer into hepatocytes in vivo has been previously reported in the rat. Before considering human applications of these techniques in the treatment of inherited liver diseases, it was necessary to document its efficiency in a large animal model. Lamb was choosen because the liver was similar to human liver regarding size and anatomy. MATERIALS AND METHODS: To induce hepatocyte division which is necessary for infection with retroviral particles, animals were subjected to a left hepatectomy. Kinetics of liver regeneration were assessed on sequential liver biopsies after partial hepatectomy in order to provide an evaluation of the peak of maximal liver regeneration in a first animal group. Recombinant retroviruses encoding a reporter gene (E. coli beta galactosidase) were then perfused through the portal vein of the regenerating liver in a second animal group. RESULTS: The more intense liver regeneration occurred from one to 6 days after partial hepatectomy, with the highest thymidine kinase rate and MIB-1 antibody staining on the second day. The proportion of genetically modified lamb hepatocytes expressing the reporter gene was less than 1%, despite the use of higher titers of retroviral particles than those described in previous reports. CONCLUSION: The results obtained in rodent livers with this in vivo gene transfer methodology cannot currently be scaled up in a large ruminant model. The efficacy of vectors has to be tested in other large mammals before planning gene therapy trials for the treatment of inherited liver diseases

In vivo retroviral-mediated transfer of a marker-gene in ornithine transcarbamylase-deficient Spf(ash) mice.

Gene therapy is a new therapeutic approach for inherited metabolic hepatopathies. The authors studied the potential application of such a strategy to the correction of ornithine transcarbamylase (OTC) deficiency by in vivo protocol of retroviral-mediated gene transfer to the liver. A partial hepatectomy was followed (24 to 48 hours later) by asanguinous perfusion of the regenerating liver with beta-galactosidase (beta-gal) recombinant retrovirus. This protocol allowed beta-gal gene transfer in normal C57B6 mice liver with 60 +/- 52 positive cells per square centimeter. This proportion never exceeded 20 cells per square centimeter in OTC-deficient spf(ash) mice. The high mortality rate for spf(ash) mice was explained by an important sensitivity of those mice to the protein catabolism rather than by technical difficulties during intraportal perfusion. This first in vivo retroviral-mediated gene transfer study in animals with a life-threatening metabolic inherited hepatopathy showed that, despite efficiency of gene therapy in normal animal models, several experimental difficulties should be overcome before human application of this protocol is considered

A new surgical approach to improve gene transfer in liver using lentiviral vectors.

PURPOSE: Metabolic inherited liver diseases are attractive targets for gene therapy. Recombinant lentiviruses are very powerful viral vectors able to infect nonmitotic cells. We wanted to develop a new surgical approach to improve gene transfer in adult liver using low viral doses. MATERIALS AND METHODS: Adult rats were injected with 2.108 infectious particles of lentiviral vectors encoding the green fluorescent protein marker gene under control of a liver-specific promoter transthyretin. In the control group (n = 5), gene delivery was performed by inflow intraportal injection. In the surgical group (n = 5), liver was completely excluded from systemic circulation before viral injection in infrahepatic vena cava with high pressure. RESULTS: At day 9, transduction efficiency was 14.35% in the surgical group 3 and 0.39% in the control group (P = .016). At month 2, the number of transduced hepatocytes decreased in the most part of rats, except in half of rats in the surgical group. Antibodies against green fluorescent protein were detected in all rats at month 2, except one in the surgical group. CONCLUSIONS: We developed a new surgical approach allowing an efficient transduction of hepatocytes in adult rats using lentivirus at low viral doses. We have now to control the immune response to permit long-term expression of transgene

Selection and validation of reference genes for quantitative RT-PCR expression studies of the non-model crop Musa

Gene expression analysis by reverse transcriptase real-time or quantitative polymerase chain reaction (RT-qPCR) is becoming widely used for nonmodel plant species. Given the high sensitivity of this method, normalization using multiple housekeeping or reference genes is critical, and careful selection of these reference genes is one of the most important steps to obtain reliable results. In this study, reference genes commonly used for other plant species were investigated to identify genes displaying highly uniform expression patterns in different varieties, tissues, developmental stages, fungal infection, and osmotic stress conditions for the non-model crop Musa (banana and plantains). The expression stability of six candidate reference genes was tested on six different sample sets, and the results were analyzed using the publicly available algorithms geNorm and NormFinder. Our results show that variety, plant material, primer set, and gene identity can all influence the robustness and outcome of RT-qPCR analysis. In the case of Musa, a combination of three reference genes (EF1, TUB and ACT) can be used for normalization of gene expression data from greenhouse leaf samples. In the case of shoot meristem cultures, numerous combinations can be used because the investigated reference genes exhibited limited variability. In contrast, variability in expression of the reference genes was much larger among leaf samples from plants grown in vitro, for which the best combination of reference genes (L2 and ACT genes) is still suboptimal. Overall, our data confirm that the stability of candidate reference gene

Tolerance and efficacy of preventive gastrostomy feeding in pediatric oncology

BackgroundMalnutrition in pediatric oncology remains underestimated, although having a negative impact on outcome. Enteral nutrition (EN) using percutaneous endoscopic gastrostomy (PEG) may prevent or reverse malnutrition consequences. We aimed to evaluate both efficacy and safety of early EN during tumors treatment in children. Procedures Medical records of pediatric patients having a PEG tube inserted between 1995 and 2009 were retrospectively reviewed. We compared type and incidence of complications in Group 1, including 74 patients suffering from cancer, and control Group 2, including 57 patients with neurological impairment. Efficacy of EN was evaluated through nutritional parameters [Z-scores weight for height (W/H) and height for age (H/A)], post-operative complications and relapse rates. Statistical significance was set for P < 0.05. Results PEG tolerance was similar in both groups, as shown by comparable complication rates (62% vs. 76%, NS). EN allowed improvement or stabilization of Z-score W/H in 76% of oncologic patients. The final height loss was lower (−0.5 vs. −1.2 SD of Z-scores H/A) when EN was started at the beginning of the oncologic treatment. In bone tumors, EN prevented weight loss during chemotherapy, and tended to lessen surgical complications, relapses and deaths. Conclusions Early gastrostomy feeding represents a relatively safe way to prevent malnutrition in children with cancer, and might play a role in bone tumors oncological outcome. Further prospective studies are needed to confirm these results and assess the impact of EN and PEG on quality of life

Factors influencing immune response after in vivo retrovirus-mediated gene transfer to the liver.

BACKGROUND: Highly efficient retrovirus-mediated gene transfer into hepatocytes in vivo triggers an immune response directed against transduced hepatocytes. This effect may be due either to spreading of retroviral vectors in the blood stream with subsequent infection of antigen presenting cells (APCs) or to cross-presentation of the transgene product present as a contaminant in the viral stock. In order to decrease immune response, we evaluated the effect of asanguineous perfusion of the liver as well as purification of the viral stock on long-term transduction of hepatocytes using the nls-lacZ marker gene. METHODS: Animals were divided in four groups. In group 1, the viral supernatant was perfused in the regenerating liver after complete vascular exclusion of the organ. In group 2, using the same strategy, animals received retroviral supernatant that was passed through a beta-galactosidase affinity column to reduce beta-galactosidase contamination. In two control groups (respectively groups 3 and 4) the corresponding viral supernatants were delivered via peripheral injection. RESULTS: In group 1, 23.1% of animals had no immune response 2 months after gene delivery vs. 33.4% in group 2, 4.3% in control group 3, and 0% in control group 4. Statistical analysis of the results demonstrated that only the difference between groups 2 and 3 was statistically significant. This indicated that both asanguineous perfusion together with passage through an affinity column were required to decrease significantly immune response. CONCLUSIONS: Our present results suggest that both supernatant contamination and viral spreading contribute to immune response after retrovirus-mediated gene delivery to the liver

Laparoscopic adjustable gastric banding in adolescents: Results at two years including psychosocial aspects

BACKGROUND/PURPOSE: Obesity now affects 3%-4% of the pediatric population and contributes to the increase in cardiac mortality in adulthood. Bariatric surgery is the best treatment for weight loss and the obesity-associated comorbidities in adults. We report here our experience of laparoscopic adjustable gastric banding (LAGB) in adolescents. METHODS: The medical charts of the first 16 patients operated on in our center were reviewed. Data were compiled concerning weight loss, physical and biological comorbidities, health-related quality of life (QOL) and surgical complications before surgery and during 24months of follow-up. RESULTS: The maximal pre-operative median body mass index was 43.0kg·m(-2), decreasing to 33.0kg·m(-2) at 2years post-LAGB, which corresponded to a 49.2% excess body weight loss (p<0.001). Most comorbidities (glucose intolerance, hypertension and sleep apnea) resolved within the first year post-LAGB and QOL was improved on the PedsQL™ scales. No severe surgical complications were noted, with only three re-interventions for device failure (2) or band removal (1). CONCLUSION: LAGB is well tolerated in adolescents and shows a beneficial impact on weight loss and obesity-related comorbidities. Associated with global management, it may have a positive impact on patients\u27 QOL and social and psychological status

Characteristics and management of congenital esophageal stenosis: findings from a multicenter study.

BACKGROUND: Congenital esophageal stenosis (CES) is a rare condition frequently associated with esophageal atresia (EA). There are limited data from small series about the presentation, treatment, and outcomes of CES. METHODS: Medical records of all patients with CES included in the French Network on Esophageal Malformations and Congenital Diseases were reviewed retrospectively with regard to diagnosis, treatment, and outcome. RESULTS: Over 18 years, 61 patients (30 boys) had CES, and 29 (47%) of these patients also had EA. The mean age at diagnosis was 24 months (1 day to 14 years) and was younger in patients with CES and EA than in those with isolated CES (7 vs. 126 months, p < 0.05). Twenty-one of the 61 patients with CES had no clinical symptoms: in three patients, the findings were incidental, and in 18 of the 29 patients with associated EA, CES was diagnosed at the time of surgical repair of EA or during a postoperative systematic esophageal barium study. In the 40 other patients, at diagnosis, 50% presented with dysphasia, 40% with vomiting, 50% with food impaction, and 42% with respiratory symptoms. Diagnosis of CES was confirmed by esophageal barium study (56/61) and/or esophageal endoscopy (50/61). Sixteen patients had tracheobronchial remnants (TBR), 40 had fibromuscular stenosis (FMS), and five had membrane stenosis (MS). Thirty-four patients (56%) were treated by dilation only (13/34 remained asymptomatic at follow-up); 15 patients were treated by dilation but required later surgery because of failure (4/15 remained asymptomatic at follow-up); and nine patients had a primary surgical intervention (4/9 were asymptomatic at follow-up). Dilation was complicated by esophageal perforation in two patients (3.4%). At follow-up, dysphagia remained in 36% (21/58) of patients, but the incidence did not differ between the EA and the isolated CS groups (10/29 vs. 7/32, p = 0.27). CONCLUSIONS: CS diagnosis can be delayed when associated with EA. Dilation may be effective for treating patients with FMS and MS, but surgical repair is often required for those with TBR. Our results show clearly that, regardless of the therapeutic option, dysphagia occurs frequently, and patients with CES should be followed over the long term

Esophageal atresia: data from a national cohort

PURPOSE: A prospective national register was established in 2008 to record all new cases of live-birth newborns with esophageal atresia (EA). This epidemiological survey was recommended as part of a national rare diseases plan. METHODS: All 38 national centers treating EA participated by completing for each patient at first discharge a questionnaire validated by a national committee of experts. Data were centralized by the national reference center for esophageal anomalies. Quantitative and qualitative analyses were performed, with P-values of less than 0.05 considered statistically significant. Results of the 2008-2009 data collection are presented in this report. RESULTS: Three hundred seven new living cases of EA were recorded between January 1, 2008, and December 31, 2009. The male/female sex ratio was 1.3, and the live-birth prevalence of EA was 1.8 per 10,000 births. Major characteristics were comparable to those reported in the literature. Survival was 95%, and no correlation with caseload was noted. CONCLUSIONS: Epidemiologic surveys of congenital anomalies such as EA, which is a rare disease, provide valuable data for public health authorities and fulfill one important mission of reference centers. When compared with previous epidemiological data, this national population-based registry suggests that the incidence of EA remains stable

Le diagnostic anténatal modifie-t-il la prise en charge néonatale et le devenir à 1 an des enfants suivis pour atrésie de l’œsophage de type III ?

OBJECTIVE: Evaluate neonatal management and outcome of neonates with either a prenatal or a post-natal diagnosis of EA type III. STUDY DESIGN: Population-based study using data from the French National Register for EA from 2008 to 2010. We compared children with prenatal versus post-natal diagnosis in regards to prenatal, maternal and neonatal characteristics. We define a composite variable of morbidity (anastomotic esophageal leaks, recurrent fistula, stenosis) and mortality at 1 year. RESULTS: Four hundred and eight live births with EA type III were recorded with a prenatal diagnosis rate of 18.1%. Transfer after birth was lower in prenatal subset (32.4% versus 81.5%, P<0.001). Delay between birth and first intervention was not significantly different. Defect size (2cm vs 1.4cm, P<0.001), gastrostomy (21.6% versus 8.7%, P<0.001) and length in neonatal unit care were higher in prenatal subset (47.9 days versus 33.6 days, P<0.001). The composite variables were higher in prenatal diagnosis subset (38.7% vs 26.1%, P=0.044). CONCLUSION: Despite the excellent survival rate of EA, cases with antenatal detection have a higher morbidity related to the EA type (longer gap). Even if it does not modify neonatal management and 1-year outcome, prenatal diagnosis allows antenatal parental counseling and avoids post-natal transfer