RESUMO
Citrullinemia type 1 (CTLN1) is an autosomal recessive disorder of metabolism caused by a deficiency of argininosuccinate synthetase. Despite optimal management, CTLN1 patients still suffer from lethal metabolic instability and experience life-threatening episodes of acute hyperammonemia. A murine model of CTLN1 (fold/fold) that displays lethality within the first 21 days of life was used to determine the efficacy of adeno-associated viral (AAV) gene transfer as a potential therapy. An AAV serotype 8 (AAV8) vector was engineered to express the human ASS1 cDNA under the control of a liver-specific promoter (thyroxine-binding globulin, TBG), AAV8-TBG-hASS1, and delivered to 7-10 days old mice via intraperitoneal injection. Greater than 95% of the mice were rescued from lethality and survival was extended beyond 100 days after receiving a single dose of vector. AAV8-TBG-hASS1 treatment resulted in liver-specific expression of hASS1, increased ASS1 enzyme activity, reduction in plasma ammonia and citrulline concentrations and significant phenotypic improvement of the fold/fold growth and skin phenotypes. These experiments highlight a gene transfer approach using AAV8 vector for liver-targeted gene therapy that could serve as a treatment for CTLN1.
Assuntos
Argininossuccinato Sintase/genética , Citrulinemia/genética , Citrulinemia/terapia , Dependovirus/genética , Terapia Genética , Fígado/enzimologia , Amônia/sangue , Animais , Argininossuccinato Sintase/deficiência , Argininossuccinato Sintase/metabolismo , Citrulina/sangue , Dependovirus/classificação , Modelos Animais de Doenças , Vetores Genéticos , Humanos , Fígado/virologia , Camundongos , Especificidade de Órgãos , Fenótipo , Globulina de Ligação a Tiroxina/genéticaRESUMO
Blood was drawn from 10 fasted, healthy volunteers and stored under standard blood bank conditions in citrate-phosphate-dextrose-adenine (CPDA-1). Blood was sampled before storage (Day 0) and on Days 5, 12, 19, 26, and 35. Laboratory testing for glucose, HbAla + b, HbAlc, pyruvic acid, lactic acid, adenosine triphosphate (ATP), 2, 3-diphosphoglycerate (2,3DPG), plasma free hemoglobin (Hb) and pH (blood gases) were performed. In addition, P50 was also serially measured in two of the individuals and in their stored blood. Significant elevations of HbAla + b and HbAlc (fast hemoglobins) were found on Days 12 and 19 of storage (p less than 0.05). These elevations of fast hemoglobins are due to hypoxia, acidosis, and hyperglycemia. Following the initial elevation of the fast hemoglobins (Hbs), there was a decline in their concentration, from Day 12, which could partly be explained by cell death.
