Efficacy and safety of Sleeping Beauty transposon-mediated gene transfer in preclinical animal studies.

Sleeping Beauty (SB) transposons have been effective in delivering therapeutic genes to treat certain diseases in mice. Hydrodynamic gene delivery of integrating transposons to 5-20% of the hepatocytes in a mouse results in persistent elevated expression of the therapeutic polypeptides that can be secreted into the blood for activity throughout the animal. An alternative route of delivery is ex vivo transformation with SB transposons of hematopoietic cells, which then can be reintroduced into the animal for treatment of cancer. We discuss issues associated with the scale-up of hydrodynamic delivery to the liver of larger animals as well as ex vivo delivery. Based on our and others' experience with inefficient delivery to larger animals, we hypothesize that impulse, rather than pressure, is a critical determinant of the effectiveness of hydrodynamic delivery. Accordingly, we propose some alterations in delivery strategies that may yield efficacious levels of gene delivery in dogs and swine that will be applicable to humans. To ready hydrodynamic delivery for human application we address a second issue facing transposons used for gene delivery regarding their potential to "re-hop" from one site to another and thereby destabilize the genome. The ability to correct genetic diseases through the infusion of DNA plasmids remains an appealing goal.

Craniofacial abnormalities in a murine knock-out model of mucopolysaccharidosis I H: a computed tomography and anatomic study.

The genetic mucopolysaccharidoses are a group of lysosomal storage diseases in which mucopolysaccharides (glycosaminoglycans) accumulate as the result of a malfunction or lack of a lysosomal degradation enzyme. There are currently seven known forms of mucopolysaccharidoses. Type I results from an enzymatic deficiency of alpha-L-iduronidase. There are three subtypes of mucopolysaccharidoses I that are commonly recognized: Hurler syndrome, Hurler-Scheie syndrome, and Scheie syndrome. Of the three subtypes, Hurler syndrome has the most severe clinical picture. Craniofacial anomalies and cognitive impairment are some of the more pronounced features of Hurler syndrome. Hurler syndrome has been described in cats, dogs, mice, and human beings and is inherited as an autosomal recessive trait. The biochemical nature of the disease is preserved across species lines. Clinically, the disease has similar effects in human beings and animals. It has been difficult to reverse the phenotype of the disease even with replacement of the defective alpha-L-iduronidase enzyme. The purpose of this study is to characterize the cranio-facial differences in the murine knock-out model of Hurler syndrome objectively. Twenty-three measurements were taken from computed tomographic scans in a coronal and sagittal plane on 24 black C57/B6 knock-out Hurler syndrome mice. The seven statistically significant measurements are width of the cervical canal, height of the foramen magnum, width between the external auditory canals, width of the skull base at the mandibular condyles, midocular distance, spread of the mandibular condyles, and width of the zygoma at the maxilla. This information now provides researchers with objective data from living Hurler syndrome-affected mice that will allow them to follow therapies directed at improving craniofacial outcomes for any therapy over time.