Dinghui Dong

Portacaval Shunt Established in Six Dogs Using Magnetic Compression Technique

Background and Aims Installing the transjugular intrahepatic portosystemic shunt for portal hypertension is relatively safe, but complications are still high. To explore a new method of portacaval shunt, the magnetic compression technique was introduced into the shunting procedure. Methods A portal-inferior vena cava shunt was performed on 6 male mongrel dogs by two hemocompatible Nd-Fe-B permanent magnets, parent and daughter. The parent magnet was applied to the inferior vena cava guided by a catheter through the femoral vein. The daughter magnet was moved to the anastomosis position on the portal vein with a balloon catheter through the splenic vein. After the daughter magnet reached the target position, the two magnets acted to compress the vessel wall and hold it in place. Five to 7 days later, under X-ray guidance, the magnets were detached from the vessel wall with a rosch-uchida transjugular liver access set. One month later, histological analysis and portal venography were performed. Results 5-7 days after the first surgery, a mild intimal hyperplasia in the portal vein and the inferior vena cava, and continuity of the vascular adventitia from the portal vein to the inferior vena cava as observed. During the second surgery, the contrast media could be observed flowing from the portal vein into the inferior vena cava. Portal venography revealed that the portosystemic shunt was still present one month after the second surgery. Conclusions Magnamosis via a device of novel design was successfully used to establish a portacaval shunt in dogs.

Using a decellularized splenic matrix as a 3D scaffold for hepatocyte cultivation in vitro: a preliminary trial.

Using a decellularized liver matrix (DLM) to reengineer liver tissue is a promising therapy for end-stage liver disease. However, the limited supply of donor organs still hampers its potential clinical application, while a xenogenic decellularized matrix may bring a risk of zoonosis and immunological rejection. Therefore, an appropriate alternative scaffold is needed. In this research, we established a decellularized splenic matrix (DSM) in a rodent model, which preserved the 3D ultrastructure, the components of the extracellular matrix (ECM) and the native vascular network. The DSM and DLM had similar components of ECM, and similar mechanical properties. Hepatocytes were seeded to the DSM and DLM for dynamic culturing up to 6 d, and distributed both in decellularized sinusoidal spaces and around the vessels. The TUNEL-positive cell percentage in a dynamic culturing decellularized splenic matrix (dDSM) was 10.7%  ±  3.6% at 3d and 25.8%  ±  5.6% at 5d, although 14.2%  ±  4.5% and 24.8%  ±  2.9%, respectively, in a dynamic culturing decellularized liver matrix (dDLM) at the same time point (p  >  0.05). Primary hepatocytes in the dDSM and dDLM expressed albumin, G6pc and Ugt1a1. The gene expression of Cyp2b1, Cyp1a2 and HNF1α in the gene transcription level revealed hepatocytes had lower gene expression levels in the dDSM compared with the dDLM at 3d, but better than those in a sandwich culture. The cumulative albumin production at 6 d of culture was 80.7   ±   9.6 μg per million cells in the dDSM and 89.6   ±   4.6 μg per million cells in the dDLM (p  >  0.05). In summary, the DSM is a promising 3D scaffold for hepatocyte cultivation in vitro.

Fast magnetic reconstruction of the portal vein with allogeneic blood vessels in canines.

BACKGROUND The resection and reconstruction of large vessels, including the portal vein, are frequently needed in tumor resection. Warm ischemia before reconstruction might have deleterious effects on the function of some vital organs and therefore, how to reconstruct the vessels quickly after resection is extremely important. The present study was to introduce a new type of magnetic compression anastomosis (MCA) device to establish a quick non-suture anastomosis of the portal vein after resection in canines. METHODS The new MCA device consists of a pair of titanium alloy and neodymium-ferrum-boron magnet (Ti-NdFeB) composite rings. The NdFeB magnetic ring as a core of the device was hermetically sealed inside the biomedical titanium alloy case. Twelve canines were divided into two groups: a MCA group in which the end-to-end anastomoses was made with a new device after resection in the portal vein and a traditional manual suture (TMS) group consisted of 6 canines. The anastomosis time, anastomotic patency and quality were investigated at week 24 postoperatively. RESULTS The portal vein was reconstructed successfully in all of the animals and they all survived. The duration of portal vein anastomosis was significantly shorter in the MCA group than in the TMS group (8.16+/-1.25 vs 36.24+/-2.17 min, P<0.05). Portography and ultrasound showed that the blood flow was normal without angiostenosis or thrombosis in all of the canines. Hematoxylin-eosin staining and electron microscope scanning showed in contrast to the TMS group, MCA anastomotic intimal was much smoother with more regularly arranged endothelial cells at week 24 postoperatively. CONCLUSIONS The Ti-NdFeB composite MCA device was applicable in reconstruction of large vessels after resection. This device was easy to use and the anastomosis was functionally better than the traditional sutured anastomosis.

Development of an in vivo visual robot system with a magnetic anchoring mechanism and a lens cleaning mechanism for laparoendoscopic single-site surgery (LESS)

Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single‐site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems.

Miniature magnetically anchored and controlled camera system for trocar-less laparoscopy

AIM To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy. METHODS The system consists of a miniature magnetically anchored camera with a 30° downward angle, an external magnetically anchored unit, and a vision output device. The camera weighs 12 g, measures Φ10.5 mm × 55 mm and has two magnets, a vision model, a light source, and a metal hexagonal nut. To test the prototype, the camera was inserted through a 12-mm conventional trocar in an ex vivo real liver laparoscopic training system. A trocar-less laparoscopic cholecystectomy was performed 6 times using a 12-mm and a 5-mm conventional trocar. In addition, the same procedure was performed in four canine models. RESULTS Both procedures were successfully performed using only two conventional laparoscopic trocars. The cholecystectomy was completed without any major complication in 42 min (38-45 min) in vitro and in 50 min (45-53 min) using an animal model. This camera was anchored and controlled by an external unit magnetically anchored on the abdominal wall. The camera could generate excellent image. with no instrument collisions. CONCLUSION The camera system we designed provides excellent optics and can be easily maneuvered. The number of conventional trocars is reduced without adding technical difficulties.

The effect of riboflavin/UVA cross‐linking on anti‐degeneration and promoting angiogenic capability of decellularized liver matrix

Weak mechanical property and unstable degradation rate limited the application of decellularized liver matrix in tissue engineering. The aim of this study was to explore a new method for improving the mechanical properties, anti-degeneration and angiogenic capability of decellularized liver matrix. This was achieved by a novel approach using riboflavin/ultraviolet A treatment to induce collagen cross-linking of decellularized matrix. Histological staining and scanning electron microscope showed that the diameter of cross-linked fibers significantly increased compared with the control group. The average peak load and Youngs modulus of decellularized matrix were obviously improved after cross-linking. Then we implanted the modified matrix into the rat hepatic injury model to test the anti-degeneration and angiogenic capability of riboflavin/UVA cross-linked decellularized liver scaffolds in vivo. The results indicated that cross-linked scaffolds degrade more slowly than those in the control group. In the experiment group, average microvessel density in the implanted matrix was higher than that in the control group since the first week after implantation. In conclusion, we initiated the method to improve the biomechanical properties of decellularized liver scaffolds by riboflavin/UVA cross-linking, and more importantly, its improvement on anti-degeneration and angiogenesis was identified.

An optimized procedure for stained bloodless anatomic hepatectomy in canines

BACKGROUND Poloxamer 407 (P407) is a thermosensitive polymer that can gelatinize at body temperature and dissolve below critical temperature. The aim of this study was to evaluate an optimized procedure for hepatectomy, in which the target liver section was stained with methylene blue, and the blood inflow was occluded with P407. METHODS Twelve dogs were randomized into two equal groups. The conventional group (CG) underwent unstained liver resection with the hemi-Pringle maneuver for blood control. After angiography, the optimized group (OG) was cannulated to the target lobar hepatic artery via the femoral artery and to the target segmental portal vein via a branch of the splenic vein. The artery was then occluded with P407, whereas the vein was administered methylene blue and P407 sequentially before excision along the stained border. Blood specimens and necropsy were acquired periodically. RESULTS The stained resection margins were clearly visualized and were accompanied by negligible blood loss. The occlusion duration was significantly reduced from 24.5 ± 2.3 min in the conventional group to 18.5 ± 4.9 min in the OG (P < 0.05). The aspartate aminotransferase and alanine aminotransferase levels were less elevated in the OG postoperatively. No significant evidence of pathology was detected in either group. CONCLUSIONS This optimized procedure represents an easy, time-saving and effective approach for stained anatomic hepatectomy with temporary intravascular blood occlusion.