An important limitation that has emerged in the use of adenoviruses for gene therapy has been loss of recombinant gene expression that occurs concurrent with the development of pathology In the organ exp g the transgene. We have used liver-dircted approaches to gene therapy in mice to study mecanims that underlie the problems with transient expression and pathology that have characterized in vivo applications of first-generation recombinant adenoviruses (i.e., those deleted of Ela and Elb). Our data are consistent with the following hypothesis. Cells harboring the recombinant viral genome express the transgene as desired; however, lowlevel expression of viral genes also occurs. A virus-specific cellular immune response is stimulated that leads to destruction of the genetically modified hepatocytes, massive hepatitis, and repopulation of the liver with nontransgene-containing hepatocytes. These findigs suggest approaches for improving recombinant adenoviruses that are based on further crippling the virus to limit expression of nondeleted viral genes.Human adenoviruses have emerged as a promising technology for in vivo gene therapy. The 36-kb double-stranded

Although first generation recombinant adenoviruses, deleted of sequences spanning E1a and E1b, have been useful for in vivo applications of gene therapy, expression of the recombinant gene has been transient and often associated with the development of inflammation. We show that with first generation adenovirus-mediated gene transfer to the mouse lung, viral proteins are expressed leading to destructive cellular immune responses and repopulation of the lung with nontransgene containing cells. Second generation E1 deleted viruses further crippled by a temperature sensitive mutation in the E2a gene were associated with substantially longer recombinant gene expression and less inflammation. Stable expression of human CF transmembrane conductance regulator has been achieved in lungs of CF mice instilled with a second generation virus.

Ornithine transcarbamylase deficiency (OTCD) is an inborn error of urea synthesis that has been considered as a model for liver-directed gene therapy. Current treatment has failed to avert a high mortality or morbidity from hyperammonemic coma. Restoration of enzyme activity in the liver should suffice to normalize metabolism. An E1- and E4-deleted vector based on adenovirus type 5 and containing human OTC cDNA was infused into the right hepatic artery in adults with partial OTCD. Six cohorts of three or four subjects received 1/2 log-increasing doses of vector from 2 x 10(9) to 6 x 10(11) particles/kg. This paper describes the experience in all but the last subject, who experienced lethal complications. Adverse effects included a flu-like episode and a transient rise in temperature, hepatic transaminases, thrombocytopenia, and hypophosphatemia. Humoral responses to the vector were seen in all research subjects and a proliferative cellular response to the vector developed in apparently naive subjects. In situ hybridization studies showed transgene expression in hepatocytes of 7 of 17 subjects. Three of 11 subjects with symptoms related to OTCD showed modest increases in urea cycle metabolic activity that were not statistically significant. The low levels of gene transfer detected in this trial suggest that at the doses tested, significant metabolic correction did not occur.

No abstract

Hyperammonemia is a potentially fatal event occurring after orthotopic lung transplantation. It is associated with high nitrogen load, concurrent medical stressors, primary pulmonary hypertension, and hepatic glutamine synthetase deficiency.

T elehealth or telemedicine, defined as "the use of communications technologies to provide and support health care at a distance," has become an important part of medical care during the coronavirus disease 2019 (COVID-19) pandemic. 1,2 In response to the emergent need to reduce the spread of COVID-19 by limiting physical contact, Medicare's 1135 Waiver lifted previous limits on patient location, range of providers, and the requirement for patients to reside in designated rural areas or for patients to have established provider relationships to receive medical services through telemedicine. Additionally, the Centers for Medicare and Medicaid Services increased reimbursement for telephone visits on par with video. 3 However, given limited telemedicine use pre-COVID-19, 4 data on clinician and patient attitudes outside of rural and research settings are lacking. We describe a real-world experience of patient-and clinician-rated acceptability of telephone and video outpatient visits during the initial 4 weeks of the emergency COVID-19 response at a large, diverse gastroenterology (GI)/hepatology practice in an academic health system.

Preclinical studies were designed to investigate the safety of recombinant adenoviruses infused into the portal vein of adult rhesus monkeys, as well as the safety and efficacy of readministration of these agents. The vectors used were recombinant adenoviruses, the E1 region of which was replaced with a marker gene expression cassette. Four 3- to 5-kg rhesus monkeys underwent portal vein cannulation, and infusion of escalating doses of recombinant first-generation vector. Serial sequential liver biopsies were performed, and necropsies were performed out to 14 months. X-Gal histochemical analysis of the liver showed evidence of dose-dependent increased gene transfer throughout the liver. Quantitative analysis of histopathology showed that portal inflammation was also present in transduced livers, and occurred in a dose-dependent manner. Severe toxicity, including mortality, was noted at the highest dose of vector. Readministration of a second vector was associated with the same degree of toxicity as the first vector, but prompted a much more vigorous neutralizing antibody response. The data suggest that intraportal administration and readministration of recombinant adenoviral E1-deleted vectors are feasible and safe. Vector administration at the highest dose (1 x 10(13) particles/kg) was associated with severe clinical and biochemical toxicity, and significant gene expression was associated with transaminitis. Readministration of vector is safe, but gene transfer is limited by the presence of neutralizing antibody.

Analysis of data from a single center and the national UNOS database suggests that transplantation of liver allografts from HCV+ donors to HCV+ recipients results in graft survival comparable to HCV- grafts transplanted to HCV+ recipients. In contrast, recipient HCV positivity is an independent predictor of graft failure compared with patients transplanted for other causes of liver disease.