ABSTRACT
OBJECTIVE: alpha-Sarcoglycan deficiency results in a severe form of muscular dystrophy (limb-girdle muscular dystrophy type 2D [LGMD2D]) without treatment. Gene replacement represents a strategy for correcting the underlying defect. Questions related to this approach were addressed in this clinical trial, particularly the need for immunotherapy and persistence of gene expression. METHODS: A double-blind, randomized controlled trial using rAAV1.tMCK.hSGCA injected into the extensor digitorum brevis muscle was conducted. Control sides received saline. A 3-day course of methylprednisolone accompanied gene transfer without further immune suppression. RESULTS: No adverse events were encountered. SGCA gene expression increased 4-5-fold over control sides when examined at 6 weeks (2 subjects) and 3 months (1 subject). The full sarcoglycan complex was restored in all subjects, and muscle fiber size was increased in the 3-month subject. Adeno-associated virus serotype 1 (AAV1)-neutralizing antibodies were seen as early as 2 weeks. Neither CD4+ nor CD8+ cells were increased over contralateral sides. Scattered foci of inflammation could be found, but showed features of programmed cell death. Enzyme-linked immunospot (ELISpot) showed no interferon-gamma response to alpha-SG or AAV1 capsid peptide pools, with the exception of a minimal capsid response in 1 subject. Restimulation to detect low-frequency capsid-specific T cells by ELISpot assays was negative. Results of the first 3 subjects successfully achieved study aims, precluding the need for additional enrollment. INTERPRETATION: The finding of this gene replacement study in LGMD2D has important implications for muscular dystrophy. Sustained gene expression was seen, but studies over longer time periods without immunotherapy will be required for design of vascular delivery gene therapy trials.
Subject(s)
Genetic Therapy/methods , Muscular Dystrophies, Limb-Girdle/therapy , Sarcoglycans/deficiency , Sarcoglycans/genetics , Adolescent , CD4 Lymphocyte Count , CD8-Positive T-Lymphocytes/immunology , Child , Dependovirus/immunology , Female , Gene Expression/genetics , Gene Transfer Techniques , Humans , Immunotherapy/methods , Male , Membrane Proteins , Muscle Fibers, Skeletal , Muscle, Skeletal/metabolism , Muscular Dystrophies, Limb-Girdle/genetics , Muscular Dystrophies, Limb-Girdle/metabolism , Neutralization Tests , Sarcoglycans/metabolismABSTRACT
Cerebral saturation (SCO2) monitors are noninvasive tools that continuously measure saturations in the cerebral cortex, a predominately venous bed. The purpose of this study was to see if a trend existed between measurements of SCO2 and mixed venous saturation values (SVO2) for patients on extracorporeal life support (ECLS). Six patients required ECLS for cardiac failure after congenital cardiac surgery, and one patient required ECLS for pulmonary failure. Patients were divided into two groups, those without systemic/pulmonary venous mixing (n = 3, Group I) and those with mixing due to an intraatrial shunt or left ventricular vent (n = 4, Group II). The age of patients was 0.4 +/- 0.5 years (mean +/- SD), weight was 5.2 +/- 2.3 kg, and time on ECLS was 8.3 +/- 4.8 days. No significant abnormalities were seen on head imaging. A total of 786 paired data points were collected. Mean values were different; however, there was a significant trend between SCO2 and SVO2 for the entire sample (R2 = 0.66, p < 0.001). Cerebral saturation trends follow mixed venous trends and, therefore, may be helpful in combination with other physical and laboratory findings in the care of the critically ill child.
