A dual AAV system enables the Cas9-mediated correction of a metabolic liver disease in newborn mice

Many genetic liver diseases present in newborns with repeated, often lethal, metabolic crises. Gene therapy using non-integrating viruses such as AAV is not optimal in this setting because the non-integrating genome is lost as developing hepatocytes proliferate1,2. We reasoned that newborn liver may be an ideal setting for AAV-mediated gene correction using CRISPR/Cas9. Here we intravenously infuse two AAVs, one expressing Cas9 and the other expressing a guide RNA and the donor DNA, into newborn mice with a partial deficiency in the urea cycle disorder enzyme, ornithine transcarbamylase (OTC). This resulted in reversion of the mutation in 10% (6.7% – 20.1%) of hepatocytes and increased survival in mice challenged with a high-protein diet, which exacerbates disease. Gene correction in adult OTC-deficient mice was lower and accompanied by larger deletions that ablated residual expression from the endogenous OTC gene, leading to diminished protein tolerance and lethal hyperammonemia on a chow diet

Ophthalmic Manifestations Among Patients Surviving COVID-19

Vagner Loduca Lima,1 Larissa Caroline Mansano Soares,1 Leonardo Amarante Pereira,1 Priscila Alves Nascimento,1 Luciano Rabello Netto Cirillo,1 Hebert Toshiaki Sakuma,1 Glaucia Luciano da Veiga,1,2 Julio Zaki Abucham-Neto,1 Fernando Luiz Affonso Fonseca1– 3 1Departamento de Oftalmologia, Faculdade de Medicina do ABC, Santo André, Brazil; 2Laboratório de Análises Clínicas, Faculdade de Medicina do ABC, Santo André, Brasil; 3Departamento de Ciências Farmacêuticas da Universidade Federal de São Paulo/UNIFESP, Diadema, BrasilCorrespondence: Glaucia Luciano da Veiga, Departamento de Oftalmologia, Faculdade de Medicina ABC, 2000 Lauro Gomes Avenue, Santo André, SP, 09069-870, Brazil, Tel +55 11 4993-5488, Email [email protected] and Aim: To identify ocular findings related to SARS-CoV-2 infection in patients after the resolution of COVID-19 using complete ocular examinations and optical coherence tomography (OCT).Methods: In this cross-sectional study, conducted from May 30 to October 30, 2020, patients who recovered from various stages COVID-19 underwent eye examination and multimodal retinal imaging (Retinographies and Spectral-OCT).Results: We included 50 patients, 29 (58%) males, median age of 46.5 [standard deviation 15.8]. Of these, 42% (21) had mild, 18% (9) had severe and 40% (20) had critical disease. The median time interquartile range (IQR) between symptom onset and ocular examination was 55 days [IQR 39– 71]. Seven patients (14%) reported ophthalmic symptoms, transitory low visual acuity (6%) and retroocular pain (8%). On OCT, one patient without comorbidities had sectoral retinal pallor suggestive of acute retinal ischaemia and oedema of the retina’s inner layers and atrophy. All findings progressively and spontaneously improved months after resolution of COVID-19.Conclusion: Patients with COVID-19 present findings compatible with the general population depending on age and comorbidities; nevertheless, acute retinal findings associated with the disease may be present, such as caused either by the direct effects of retinal SARS-CoV-2 infection, by indirect effects of the cytokine storm or by the pro-thrombotic state associated with COVID-19. Therefore, retinal involvement in patients with COVID-19 remains subject to considerable discussion and study.Keywords: COVID-19, retina, ophthalmology, Sars-Cov-2, eye manifestation