Delivery and evaluation of recombinant adeno-associated viral vectors in the equine distal extremity for the treatment of laminitis.

REASONS FOR PERFORMING STUDY: Our long-term aim is to develop a gene therapy approach for the prevention of laminitis in the contralateral foot of horses with major musculoskeletal injuries and non-weightbearing lameness. OBJECTIVES: The goal of this study was to develop a practical method to efficiently deliver therapeutic proteins deep within the equine foot. STUDY DESIGN: Randomised in vivo experiment. METHODS: We used recombinant adeno-associated viral vectors (rAAVs) to deliver marker genes using regional limb perfusion through the palmar digital artery of the horse. RESULTS: Vector serotypes rAAV2/1, 2/8 and 2/9 all successfully transduced equine foot tissues and displayed similar levels and patterns of transduction. The regional distribution of transduction within the foot decreased with decreasing vector dose. The highest transduction values were seen in the sole and coronary regions and the lowest transduction values were detected in the dorsal hoof-wall region. The use of a surfactant-enriched vector diluent increased regional distribution of the vector and improved the transduction in the hoof-wall region. The hoof-wall region of the foot, which exhibited the lowest levels of transduction using saline as the vector diluent, displayed a dramatic increase in transduction when surfactant was included in the vector diluent (9- to 81-fold increase). In transduced tissues, no significant difference was observed between promoters (chicken ß-actin vs. cytomegalovirus) for gene expression. All horses tested for vector-neutralising antibodies were positive for serotype-specific neutralising antibodies to rAAV2/5. CONCLUSIONS: The current experiments demonstrate that transgenes can be successfully delivered to the equine distal extremity using rAAV vectors and that serotypes 2/8, 2/9 and 2/1 can successfully transduce tissues of the equine foot. When the vector was diluted with surfactant-containing saline, the level of transduction increased dramatically. The increased level of transduction due to the addition of surfactant also improved the distribution pattern of transduction.

Adeno-associated virus serotypes 9 and rh10 mediate strong neuronal transduction of the dog brain.

Canine models have many advantages for evaluating therapy of human central nervous system (CNS) diseases. In contrast to nonhuman primate models, naturally occurring canine CNS diseases are common. In contrast to murine models, the dog's lifespan is long, its brain is large and the diseases affecting it commonly have the same molecular, pathological and clinical phenotype as the human diseases. We compared the ability of four intracerebrally injected adeno-associated virus vector (AAV) serotypes to transduce the dog brain with green fluorescent protein as the first step in using these vectors to evaluate both delivery and efficacy in naturally occurring canine homologs of human diseases. Quantitative measures of transduction, maximum diameter and area, identified both AAV2/9 and AAV2/rh10 as significantly more efficient than either AAV2/1 or AAV2/5 at transducing cerebral cortex, caudate nucleus, thalamus and internal capsule. Fluorescence co-labeling with cell-type-specific antibodies demonstrated that AAV2/9 and AAV2/rh10 were capable of primarily transducing neurons, although glial transduction was also identified and found to be more efficient with the AAV2/9 vector. These data are a prerequisite to evaluating the efficacy of recombinant AAV vectors carrying disease-modifying transgenes to treat naturally occurring canine models in preclinical studies of human CNS disease therapy.

Myopathy as the first symptom of hypokalemic periodic paralysis--case report of a girl from a Polish family with CACNA1S (R1239G) mutation.

PURPOSE: Presenting the case of unusual onset hypokalemic periodic paralysis (HypoPP) where myopathy had developed two years before paralysis occurred. MATERIAL AND METHODS: A Polish three-generation family with HypoPP and mutation in CACNA1S (R1239G) has been investigated. Clinical presentation with unusual onset of the disease, biopsy results and genetic research in one family member were described. CONCLUSION: HypoPP is a rare disease it needs to be taken into consideration not only in cases of paroxysmal weakness but also when there is myopathy of unknown origin.