Innovative application of an implantable venous access system in the portal vein: technique, results and complications in three dogs.

BACKGROUND: Vascular access port (VAP) systems are widely used in human medicine to provide long-term venous access. However, in veterinary medicine the use of VAP systems is not common practice and publications on their potential applications have been limited. A VAP system was used as part of an experimental study on liver regeneration and implanted in the canine portal vein to create direct access to the portal venous circulation of the liver. The aim of the present study is to describe the surgical technique, its use, and the complications of a VAP system in three research dogs. RESULTS: The VAP system was successfully used for the intraoperative measurement of portal blood pressure, the administration of cell suspensions, and the collection of portal venous blood samples. Long-term complications consisted of dislocation of the VAP system in one dog (2 months after implantation) and thrombus formation at the catheter tip in two dogs (3 months after implantation). Both complications prevented further use of the VAP but had no adverse clinical implications. CONCLUSIONS: This pilot study suggests that the VAP system is an effective and safe technique to obtain long term access to the portal venous system in dogs. However, complications with port detachment and thrombosis may limit long term use of VAPs in the portal system of dogs.

The effect of neuromuscular blockade on canine laparoscopic ovariectomy: a double-blinded, prospective clinical trial.

OBJECTIVE: To evaluate the effect of neuromuscular blockade (NMB) on surgical time and various anesthetic variables during laparoscopic ovariectomy in dogs. STUDY DESIGN: Prospective, double-blinded, randomized clinical trial. ANIMALS: Female dogs (n = 40). METHODS: Laparoscopic ovariectomy by bipolar electrocoagulation was performed by 1 surgeon using a standardized protocol, where 1 ovary was removed under NMB, and the other without NMB. Surgical and anesthetic (respiratory and circulatory) variables were recorded for predetermined procedural stages and were statistically evaluated. RESULTS: Mean total surgical time was 25.1 ± 6.3 minutes (range, 16-47 minutes). With NMB, mean duration of surgical excision of the ovary (5.7 ± 2.3 minutes) was not significantly changed compared to ovariectomy without NMB (5.9 ± 1.9 minutes). Arterial blood pressure was the only recorded anesthetic variable that significantly changed under NMB (5% decrease). Occurrence of intraoperative complications did not differ. In obese dogs, total surgical time was increased by 22%. Other variables, including occurrence of intraoperative mesovarial bleeding did not influence surgical duration. CONCLUSIONS: NMB did not significantly improve laparoscopic ovariectomy times and except for a 5% decrease in arterial blood pressure did not change any of the evaluated anesthetic and surgical variables.

Long-Term Survival of Transplanted Autologous Canine Liver Organoids in a COMMD1-Deficient Dog Model of Metabolic Liver Disease.

The shortage of liver organ donors is increasing and the need for viable alternatives is urgent. Liver cell (hepatocyte) transplantation may be a less invasive treatment compared with liver transplantation. Unfortunately, hepatocytes cannot be expanded in vitro, and allogenic cell transplantation requires long-term immunosuppression. Organoid-derived adult liver stem cells can be cultured indefinitely to create sufficient cell numbers for transplantation, and they are amenable to gene correction. This study provides preclinical proof of concept of the potential of cell transplantation in a large animal model of inherited copper toxicosis, such as Wilson's disease, a Mendelian disorder that causes toxic copper accumulation in the liver. Hepatic progenitors from five COMMD1-deficient dogs were isolated and cultured using the 3D organoid culture system. After genetic restoration of COMMD1 expression, the organoid-derived hepatocyte-like cells were safely delivered as repeated autologous transplantations via the portal vein. Although engraftment and repopulation percentages were low, the cells survived in the liver for up to two years post-transplantation. The low engraftment was in line with a lack of functional recovery regarding copper excretion. This preclinical study confirms the survival of genetically corrected autologous organoid-derived hepatocyte-like cells in vivo and warrants further optimization of organoid engraftment and functional recovery in a large animal model of human liver disease.