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Tay-Sachs disease (TSD) is a fatal neurodegenerative disorder caused by a deficiency of the enzyme hexosaminidase A (HexA). TSD also occurs in sheep, the only experimental model of TSD that has clinical signs of disease. The natural history of sheep TSD was characterized using serial neurological evaluations, 7 Tesla magnetic resonance imaging, echocardiograms, electrodiagnostics, and cerebrospinal fluid biomarkers. Intracranial gene therapy was also tested using AAVrh8 monocistronic vectors encoding the α-subunit of Hex (TSD α) or a mixture of two vectors encoding both the α and β subunits separately (TSD α + β) injected at high (1.3 × 10 vector genomes) or low (4.2 × 10 vector genomes) dose. Delay of symptom onset and/or reduction of acquired symptoms were noted in all adeno-associated virus-treated sheep. Postmortem evaluation showed superior HexA and vector genome distribution in the brain of TSD α + β sheep compared to TSD α sheep, but spinal cord distribution was low in all groups. Isozyme analysis showed superior HexA formation after treatment with both vectors (TSD α + β), and ganglioside clearance was most widespread in the TSD α + β high-dose sheep. Microglial activation and proliferation in TSD sheep-most prominent in the cerebrum-were attenuated after gene therapy. This report demonstrates therapeutic efficacy for TSD in the sheep brain, which is on the same order of magnitude as a child's brain.

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Pimobendan appeared to be well tolerated in cats with heart failure characterized by ventricular systolic dysfunction of various etiologies. Cats with systolic anterior motion of the mitral valve may develop systemic hypotension when treated with pimobendan. Additional studies are needed to establish dosages for pimobendan and its effects before it can be recommended for treatment of cats with CHF.

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OBJECTIVE To assess signalment and concurrent disease processes in dogs with aortic thrombotic disease (ATD). DESIGN Retrospective case-control study. ANIMALS Dogs examined at North American veterinary teaching hospitals from 1985 through 2011 with medical records submitted to the Veterinary Medical Database. PROCEDURES Medical records were reviewed to identify dogs with a diagnosis of ATD (case dogs). Five control dogs without a diagnosis of ATD were then identified for every case dog. Data were collected regarding dog age, sex, breed, body weight, and concurrent disease processes. RESULTS ATD was diagnosed in 291 of the 984,973 (0.03%) dogs included in the database. The odds of a dog having ATD did not differ significantly by sex, age, or body weight. Compared with mixed-breed dogs, Shetland Sheepdogs had a significantly higher odds of ATD (OR, 2.59). Protein-losing nephropathy (64/291 [22%]) was the most commonly recorded concurrent disease in dogs with ATD. CONCLUSIONS AND CLINICAL RELEVANCE Dogs with ATD did not differ significantly from dogs without ATD in most signalment variables. Contrary to previous reports, cardiac disease was not a common concurrent diagnosis in dogs with ATD.

A common challenge in cell therapy is the inability to routinely maintain survival and localization of injected therapeutic cells. Delivering cells by direct injection increases the flexibility of clinical applications, but may cause low cell viability and retention rates due to the high shear forces in the needle and mechanical wash out. In this study, we encapsulated endothelial colony forming cells (ECFCs) in poly(ethylene glycol)-fibrinogen (PF) hydrogel microspheres using a custom-built microfluidic device; this system supports rapid encapsulation of high cell concentrations (10 million cells per mL) and resulting cell-laden microspheres are highly uniform in shape and size. The encapsulated ECFCs were shown to have >95% viability and continued to rapidly proliferate. Expression of cell markers (von Willebrand factor, CD105, and CD14), the ability to form tubules on basement membrane matrix, and the ability to take up low-density lipoprotein were similar between pre- and post-encapsulated cells. Viability of encapsulated ECFCs was maintained after shear through 18-23-gauge needles. Ex vivo and in vivo cell delivery studies were performed by encapsulating and injecting autologous equine ECFCs subcutaneously into distal limb full-thickness wounds of adult horses. Injected ECFCs were visualized by labeling with fluorescent nanodots before encapsulation. One week after injection, confocal microscopy analysis of biopsies of the leading edges of the wounds showed that the encapsulated ECFCs migrated into the surrounding host tissue indicating successful retention and survival of the delivered ECFCs. Rapid, scalable cell encapsulation into PF microspheres was demonstrated to be practical for use in large animal cell therapy and is a clinically relevant method to maintain cell retention and survival after local injection.

Background: Endothelial colony forming cells (ECFCs) may be useful therapeutically in conditions with poor blood supply, such as distal limb wounds in the horse. Encapsulation of ECFCs into injectable hydrogel microspheres may ensure cell survival and cell localization to improve neovascularization and healing. Autologous ECFCs were isolated from 6 horses, labeled with quantum nanodots (QD), and a subset were encapsulated in poly(ethylene) glycol fibrinogen microspheres (PEG-Fb MS). Full-thickness dermal wounds were created on each distal limb and injected with empty PEG-Fb MS, serum, ECFCs, or ECFCs encapsulated into PEG-Fb MS (ECFC/MS). Analysis included wound surface area (WSA), granulation tissue scoring (GS), thermography, collagen density staining, and immunohistochemical staining for endothelial and inflammatory cells. The purpose of this study was to track cell location and evaluate wound vascularization and inflammatory response after injection of ECFC/MS or naked ECFCs in equine distal limb wounds. Results: ECFCs were found near and within newly formed blood vessels up to 3 weeks after injection. ECFC and ECFC/MS groups had the greatest blood vessel quantity at week 1 in the wound periphery. Wounds treated with ECFCs and ECFC/MS had the lowest density of neutrophils and macrophages at week 4. There were no significant effects of ECFC or ECFC/MS treatment on other measured parameters. Conclusions: Injection of microsphere encapsulated ECFCs was practical for clinical use and well-tolerated. The positive ECFC treatment effects on blood vessel density and wound inflammation warrant further investigation.