Percutaneous transhepatic portal catheterization guided by ultrasound technology for islet transplantation in rhesus monkey.

BACKGROUND: Pig islet xenotransplantation has the potential to overcome the shortage of donated human islets for islet cell transplantation in type 1 diabetes. Testing in non-human primate models is necessary before clinical application in humans. Intraportal islet transplantation in monkeys is usually performed by surgical infusion during laparotomy or laparoscopy. In this paper, we describe a new method of percutaneous transhepatic portal catheterization (PTPC) as an alternative to current methods of islet transplantation in rhesus monkeys. METHODS: We performed ultrasound-guided PTPC in five adult rhesus monkeys weighing 7-8 kg, with portal vein catheterization confirmed by digital subtraction angiography. We monitored for complications in the thoracic and abdominal cavity. To evaluate the safety of ultrasound-guided PTPC, we recorded the changes in portal pressure throughout the microbead transplantation procedure. RESULTS: Ultrasound-guided PTPC and infusion of 16 000 microbeads/kg body weight into the portal vein was successful in all five monkeys. Differences in the hepatobiliary anatomy of rhesus monkeys compared to humans led to a higher initial complication rate. The first monkey died of abdominal hemorrhage 10 hours post-transplantation. The second suffered from a mild pneumothorax but recovered fully after taking only conservative measures. After gaining experience with the first two monkeys, we decreased both the hepatic puncture time and the number of puncture attempts required, with the remaining three monkeys experiencing no complications. Portal pressures initially increased proportional to the number of transplanted microbeads but returned to pre-infusion levels at 30 minutes post-transplantation. The changes in portal pressures occurring during the procedure were not significantly different. CONCLUSIONS: Ultrasound-guided PTPC is an effective, convenient, and minimally invasive method suitable for use in non-human primate models of islet cell transplantation provided that care is taken with hepatic puncture. Its advantages must be weighed against the risks of procedure-related complications.

[Experimental study of portal hemodynamics after microcapsule transplantation by intraportal and transarterial approach].

OBJECTIVE: To compare the changes of portal hemodynamics after microcapsule transplantation by intraportal and transarterial approach with color doppler sonography. METHODS: Thirty male dogs were divided into 2 groups randomly: Group PV (microcapsules implanted into the portal vein) and Group HA (microcapsules implanted into the hepatic artery). Both groups were divided into 3 subgroups(PV1, PV2, and PV3; HA1, HA2, and HA3) according to the number of implanted microcapsules (8,000/kg, 16,000/kg, and 32,000/kg). The internal diameter and flow velocity of the portal vein were measured with color doppler sonography before the transplantation,within 24 hours and 1, 2, and 4 weeks after microcapsule transplantation. RESULTS: The flow velocity of the portal vein in Group PV1 and PV2 within 24 hours increased significantly (P<0.05); The meanwhile the internal diameters did not change significantly (P> 0.05). The flow velocity of the portal vein in Group PV3 within 24 hours decreased significantly (P<0.05), but the internal diameter increased significantly (P<0.05). Portal hemodynamics of different transarterial subgroups did not change significantly (P> 0.05). The level of ALT in Group PV and Group HA all increased significantly (P<0.05). And when the numbers of microcapsule transplantation were same, the level of ALT in subgroup PV were significantly higher than that in subgroup HA (P<0.05). CONCLUSION: Microcapsule transplantation by transarterial approach is safer than by intraportal way, and the hepatic artery can contain more microcapsule than the portal vein.