Portal vein thrombosis after intraportal hepatocytes transplantation in a liver transplant recipient

Hepatocytes transplantation is viewed as a possible alternative or as a bridge therapy to liver transplantation for patients affected by acute or chronic liver disorders. Very few data regarding complications of hepatocytes transplantation is available from the literature. Herein we report for the first time a case of portal vein thrombosis after intraportal hepatocytes transplantation in a liver transplant recipient. A patient affected by acute graft dysfunction, not eligible for retransplantation, underwent intraportal infusion of 2 billion viable cryopreserved ABO identical human allogenic hepatocytes over a period of 5 h. Hepatocytes were transplanted at a concentration of 14 million/ml for a total infused volume of 280 ml. Doppler portal vein ultrasound and intraportal pressure were monitored during cell infusion. The procedure was complicated, 8 h after termination, by the development of portal vein thrombosis with liver failure and death of the patient. Autopsy showed occlusive thrombosis of the intrahepatic portal vein branches; cells or large aggregates of epithelial elements (polyclonal CEA positive), suggestive for transplanted hepatocytes, were co-localized inside the thrombus.     

Trasplante celular hepático. Aspectos técnicos y metodológicos

Hepatic cell transplantation consists of grafting already differentiated cells such as hepatocytes. Human hepatocytes are viable and functionally active.Liver cell transplantation is carried out by means of a 3-step method: isolation of hepatocytes from donor liver rejected for orthotopic transplantation, preparing a cell suspension for infusion and, finally, hepatocytes are implanted into the recipient. There are established protocols for the isolation of human hepatocytes from unused segments of donor livers, based on collagenase digestion of cannulated liver tissue at 37 °C.The hepatocytes can be used fresh or cryopreserved. Cryopreservation of isolated human hepatocytes would then be available for planned use.In cell transplant, the important aspects are: infusion route, number of cells, number of infusions and viability of the cells. The cells are infused into the patient through a catheter inserted via portal vein or splenic artery.Liver cell transplantation allows liver tissue to be used that would, otherwise, be discarded, enabling multiple patients to be treated with hepatocytes from a single tissue donor.     

Living-related liver transplantation with renoportal anastomosis for a patient with large spontaneous splenorenal collateral

BACKGROUND: A large splenorenal collateral must be interrupted during liver transplantation to secure adequate portal perfusion. However, this process increases the complexity of the operative procedure and may cause hazardous bleeding. Recently, renoportal anastomosis in portal reconstruction was reported in cadaveric liver transplantation for patients with surgically created splenorenal shunts. We used this technique in a living-related liver transplantation. METHODS: A 29-year-old female with a large spontaneous splenorenal collateral and a portal venous thrombus underwent a living-related liver transplantation. At surgery, the left renal vein was divided and the distal stump was anastomosed to the portal vein of the graft without interrupting collaterals. RESULTS: Adequate portal venous blood flow was maintained throughout the postoperative course. The patient was discharged 9 weeks after transplantation and remains well. CONCLUSION: The renoportal anastomosis could be used for portal reconstruction in living-related liver transplantation for patients with a large splenorenal collateral. It provides adequate portal perfusion without interrupting collateral circulation.     

Enhanced proliferation of hepatic progenitor cells in rats after portal branch occlusion.

It is known that hepatic progenitor cells increase in number after liver injury caused by carcinogens, but this injury cannot be reproduced in humans. In order to create a practical source of hepatic progenitor cells, changes in the number of liver epithelial cells (LECs), a type of hepatic progenitor cell, were examined following partial interruption of the portal flow. Efficiency in this isolation procedure was investigated, and isolated LECs were transplanted into livers to demonstrate their differentiation into hepatocytes in vivo.A volume of 70% of Sprague-Dawley rat's livers was exposed to portal vein ligation. LECs, identified as alpha-fetoprotein (AFP)-positive and albumin-negative cells, were counted and LECs isolated from the portal vein ligated-lobe were characterized by immunostaining and Western blotting. Isolated cells were subjected to a 1-week-culture, and the number of colonies formed on dishes was counted. The cells were then transplanted to the livers of genetic analbuminemic rats and identified by immunohistochemistry. The number of LECs in the portal ligated-lobes on day 7 was 14.7 +/- 6.5 cells/1,000 hepatocytes: 18 times higher than numbers in a normal liver. A significant increase was noted from day 3 until day 28. Isolated LECs were AFP-positive, albumin-negative, and cytokeratin-19-positive cells. The number of colonies on the 7th day following portal vein ligation was 42 times higher than in a normal liver. After transplantation of the LECs to the analbuminemic rat, a cluster of albumin-producing cells was present until day 56, suggesting that they differentiate into hepatocytes. We conclude that after portal vein occlusion, the liver can be a good source of hepatic progenitor cell. These results open up the possibility of cellular transplantation for liver functional support in clinical settings.     

Rescue of Acute Portal Vein Thrombosis After Liver Transplantation Using a Cavoportal Shunt at Re-transplantation

BACKGROUND: Portal vein thrombosis is a rare but devastating complication following orthotopic liver transplantation. Fulminant liver failure ensues with acute portal vein thrombosis after transplantation limiting the treatment options. METHODS: We successfully re-transplanted a 46-year-old female patient who developed acute portal vein thrombosis 19 d after orthotopic liver transplantation. Vascular reconstruction included a cavoportal shunt to augment portal blood flow. RESULTS: Twelve months after re-transplantation this patient lives independently and enjoys excellent liver allograft function. CONCLUSIONS: Cavoportal shunt can augment portal blood flow in adult recipients of orthotopic liver transplants. This technique can be successfully employed during re-transplantation when portal blood flow is inadequate to maintain patency.     

Efficient hepatocyte engraftment in a nonhuman primate model after partial portal vein embolization

BACKGROUND: Hepatocyte transplantation could be an alternative to whole liver transplantation for the treatment of metabolic liver diseases. However, the results of clinical investigations suggest that the number of engrafted hepatocytes was insufficient to correct metabolic disorders. This may partly result from a lack of proliferation of transplanted hepatocytes. In rodents, portal ligation enhances hepatocyte engraftment after transplantation. We investigated the effects of partial portal ligation and embolization on engraftment and proliferation of transplanted hepatocytes in primates. METHODS: Hepatocyte autotransplantation was performed in Macaca monkeys. The left lateral lobe was resected for hepatocyte isolation. The first group of monkeys underwent surgical ligation of the left and right anterior portal branches; in the second group, the same portal territories were obstructed by embolization with biological glue. To evaluate the proportion of cell engraftment hepatocytes were Hoechst-labeled and transplanted via the portal vein. Cell proliferation was measured by BrdU incorporation. RESULTS: Hepatocyte proliferation was induced by both procedures but it was significantly higher after partial portal embolization (23.5% and 11.2% of dividing hepatocytes on days 3 and 7) than after ligation (3% and 0.8%). Hepatocytes engrafted more efficiently after embolization than after ligation. They proliferated and participated to liver regeneration representing 10% of the liver mass on day seven and their number remained constant on day 15. CONCLUSIONS: These data suggest that partial portal embolization of the recipient liver improves engraftment of transplanted hepatocytes in a primate preclinical model providing a new strategy for hepatocyte transplantation.     

Improved technique of heterotopic auxiliary rat liver transplantation with portal vein arterialization

BACKGROUND AND AIMS: In acute, potentially reversible hepatic failure, auxiliary liver transplantation is a promising alternative approach. Using the auxiliary partial orthotopic liver transplantation (APOLT) method--the orthotopic implantation of auxiliary segments--most of the technical problems (lack of space for the additional liver mass, the portal vein reconstruction, and the venous outflow) are avoided, but extensive resections of the native liver and the graft are necessary. Erhard described the heterotopic auxiliary liver transplantation (HALT) with portal vein arterialization (PVA). Initial clinical results demonstrated that an adequate liver function can be achieved using this technique. We developed and improved a technique of HALT with flow-regulated PVA in the rat to perform further investigations. The aim of this paper is to explain in detail this improved experimental surgical technique. MATERIALS AND METHODS: Liver transplantations were performed in 122 male Lewis rats: After a right nephrectomy, the liver graft, which was reduced to about 30% of the original size, was implanted into the right upper quadrant of the recipient's abdomen. The infrahepatic caval vein was anastomosed end-to-side. The donor's portal vein was completely arterialized to the recipient's right renal artery in stent technique. Using a stent with an internal diameter of 0.3 mm, the flow in the arterialized portal vein was regulated to achieve physiologic parameters. The celiac trunk of the graft was anastomosed to the recipient's aorta, end-to-side. The bile duct was implanted into the duodenum. RESULTS: After improvements of the surgical technique, we achieved a perioperative survival of 90% and a 6-week survival of 80% in the last 112 transplantations. CONCLUSION: We developed a standardized and improved technique, which can be used for experiments of regeneration and inter-liver competition in auxiliary liver transplantation. Furthermore, this technique is suitable for the investigation of the influence of portal vein arterialization and portal hyperperfusion on liver microcirculation, function, and morphology.     

Caval inflow to the graft: a successful way to overcome diffuse portal system thrombosis in liver transplantation

Portal vein thrombosis was considered to be a major contraindication to liver transplantation before the introduction of vessel grafts from the recipient's area of confluence of the splenic and superior mesenteric veins, behind the neck of the pancreas, to the graft's portal vein. Refinement in surgical technique has given rise to a large number of possibilities to overcome portal vein thrombosis in OLT recipients, ranging from portal vein thrombectomy to several different venous graft jump reconstructions. All these reconstructions require the presence of a patent vein of the portal system. When neither splanchnic veins nor sufficiently large venous collaterals are available, liver transplantation has been considered impossible. Salvage solutions include arterialization of the portal vein with the associated risk of liver damage in the longterm, a combined liver and bowel transplantation has been proposed but not yet reported (and in any case the results of combined liver and bowel transplants are not as good as those of liver transplantation alone) and finally the use of blood inflow from the inferior vena cava as first reported by Tzakis and coworkers. Portal flow from the inferior vena cava may be performed as a last resort. Although the consequences of severe pretransplantation portal hypertension remain and should be treated before, during, and after transplantation, liver function is normal in the short and midterm. With this new procedure, diffuse portal vein thrombosis is no longer an absolute contraindication to liver transplantation. But this needs to be confirmed in light of further experience and longterm followup.     

Arterialization of the portal vein in liver transplantation: a new microsurgical model in the rat

BACKGROUND: A preexisting thrombosis of the portal vein and the deep splanchnic bed can make it extremely difficult to reestablish the portal blood flow in orthotopic liver transplantation in man. Complete arterialization of the liver transplant, including the donor portal vein, might be a viable therapeutic option. A new rat transplantation model is described, in which the liver is completely arterialized. METHODS: The outflow of the portal blood in the recipient was secured via a portocaval shunt. Hepatectomy was then performed and the liver transplant placed in orthotopic position. An interposed aortic segment was used for direct arterialization of the donor portal vein. RESULTS: The laboratory parameters determined in the serum at the end of the observation period of 28 days revealed normal functioning of the transplant. The histological examinations showed largely normal cellular architecture, with no signs of necrosis, but incipient fibrosis. CONCLUSIONS: Using this new surgical technique in the rat liver transplantation model, long-term morphological and functional changes in a completely arterialized liver graft, and the regenerative capability of liver tissue perfused in this way, can be investigated.     

Hepatocellular transplantation in acute liver failure.

Acute liver failure carries a high rate of mortality, but if metabolic support can be maintained for a critical period, liver healing and recovery are possible. Current techniques of temporary hepatic support are cumbersome and inconsistently effective. We studied the ability of dispersed hepatocytes to provide metabolic support when transplanted to rats with liver failure induced by dimethylnitrosamine (DMNA), a rapidly metabolized agent that is selectively toxic to liver cells. DMNA (20 mg/kg) was administered intravenously to 92 Lewis rats. Animals were divided into four groups receiving the following treatments 24 hours after DMNA administration: group I-intraperitoneal transplantation of hepatocytes prepared from 2.0 gm of normal isologous rat liver; group II-infusion into the portal vein of hepatocytes prepared from 1.5 gm of liver; group III-infusion of saline into the portal vein; group IV-no further treatment. The percentages surviving in each group 3 weeks after DMNA administration were 63%, 71%, 17%, and 6%, respectively. Mean serum glutamic oxaloacetic transaminase (SGOT) levels 3 days after DMNA administration were similar in the four groups, indicating that the degree of liver damage was equivalent. A significantly higher proportion of hepatocyte treated rats survived. Liver histology after DMNA administration showed hemorrhagic central lobular necrosis. A return to near-normal architecture occurred by 3 weeks in surviving animals. In group II hepatocytes were seen in portal venules, sinusoids, and central veins. We conclude that dispersed hepatocytes, transplanted either intraperitoneally or via the portal vein, can provide sufficient metabolic support to allow for recovery from drug-induced hepatic necrosis.     

Percutaneous portal vein thrombolysis and endovascular stent for management of posttransplant portal venous conduit thrombosis

BACKGROUND: Thrombosis of a portal vein conduit after liver transplant is an uncommon clinical situation. Percutaneous thrombolytic therapy for this condition has not been widely described. METHODS: We describe a case of thrombosis of a portal vein (PV) conduit subsequent to orthotopic liver transplantation that was successfully treated by percutaneous portal vein thrombolysis by using tissue plasminogen activator, angioplasty, and endovascular stent placement. RESULTS: A satisfactory outcome was achieved with a patent portal vein, on ultrasound, at 8-month follow-up. CONCLUSION: A percutaneous transhepatic approach to treatment of thrombosis of a portal vein conduit appears to be a promising technique to use to avoid surgery, with good medium-term results.     

A new bioabsorbable material for rat orthotopic liver transplantation.

Rat orthotopic liver transplantation was performed using a newly synthesized bioabsorbable material (LA-GA copolymer) cuffs and the ordinary polyethylene cuffs. The LA-GA copolymer cuff which anastomosed the portal vein was patent and developed no collateral veins even after 6 months, keeping the transplanted liver normal. By contrast, the polyethylene cuff-anastomosed portal vein was completely occluded and the collateral veins were highly developed, with the transplanted liver showing the fatty degeneration of hepatocytes and numerous regenerative nodules. It is concluded that the LA-GA copolymer cuff is a suitable material for the short- and long-term study of rat orthotopic liver transplantation.     

Using Pericholedochal Varix Inflow for Complete Portal Vein Thrombosis in Living Donor Liver Transplantation: A Case Report

One of the crucial steps of liver transplantation is to provide the portal inflow. Portal vein thrombosis is the most challenging factor to achieve. Using a pericholedochal varix for portal inflow in a patient with complete portal vein thrombosis in living donor liver transplantation (LDLT) is a rare technique. We present our experience of a LDLT with PVT.     

Hyperbaric oxygenation after portal vein emobilization for regeneration of the predicted remnant liver

BACKGROUND: Liver failure often develops after extensive liver resection. Preoperative portal vein embolization to induce compensatory hypertrophy in the predicted remnant liver decreases clinical complications after hepatectomy. The aim of this study was to examine whether hyperbaric oxygenation (HBO) after portal vein embolization increases compensatory hypertrophy of the predicted liver remnant. We performed portal vein ligation and HBO in rats to investigate whether HBO after portal vein embolization increases compensatory hypertrophy of the predicted remnant liver. METHODS: Rats were divided into four groups that underwent (1) laparotomy only (control group); (2) right portal vein ligation (RPL group); (3) RPL followed by HBO at 2 atm (HBO-2 atm group; 1 h/day, 5 days/week for 2 weeks); or (4) RPL followed by HBO at 3 atm (HBO-3 atm group). Laparotomy was repeated after 2 weeks in each group; serum levels of albumin and hepatocyte growth factor (HGF) were measured, and the ratio of the weights of nonligated to ligated hepatic segments and the percentage of hepatocytes expressing proliferating cell nuclear antigen (PCNA) in ligated hepatic segments were determined. RESULTS: In rats that had received HBO after RPL, serum levels of HGF, weight ratios of nonligated to ligated hepatic segments, and the percentage of PCNA-positive hepatocytes in nonligated liver were significantly higher than those in the control group. Furthermore, rats that had undergone 3-atm HBO after RPL had significantly higher serum levels of HGF and percentages of PCNA-positive hepatocytes in nonligated hepatic segments. CONCLUSIONS: Preoperative HBO after portal vein embolization may be useful for inducing compensatory hypertrophy of the predicted remnant liver.     

Use of the middle colic vein for liver cell transplantation in infants and small children

INTRODUCTION: Because it is less invasive, intraportal liver cell transplantation (LCT) is an interesting alternative to whole organ transplantation. The inferior mesenteric vein is usually chosen for portal vein access. However, anatomical variations are common in children, so we investigated catheter insertion into the middle colic vein. PATIENTS AND METHODS: Three children (3 weeks to 3 years; 3 to 14 kg) underwent LCT in our center for acute liver failure or severe neonatal urea cycle disorders. Small 4.2-French Hickman lines were surgically introduced into the middle colic vein and advanced to the portal vein stem. The patients received repetitive infusions of liver cells over a period of 4-11 days. RESULTS: Catheter insertion was feasible and tolerated well despite the poor clinical condition of 1 patient and the metabolic instability in the other 2 patients. Blood could be drawn from all catheters, and measurement of portal vein pressure was possible in 2 children. The patient with acute liver failure died after 11 days from complications of the underlying disease. In the other 2 children, portal vein catheters stayed patent for several months. CONCLUSIONS: The middle colic vein can be recommended for placement of intraportal LCT catheters even in small and critically ill infants.     

Permanent access to the portal vein in rats: an experimental model

A safe and reproducible method for placement of indwelling catheters into the portal venous system is a prerequisite for improved delivery of anticancer drugs to experimental liver metastases. Due to the lack of tumor models in large animals and the difficulty in establishing permanent access to the portal vein in rodents, this type of model has rarely been described in the laboratory setting. We propose a simple, minimally invasive method for repeated portal vein injections in rats. A vascular access device was used, which remained patent for periods of up to 3 months. Placement and support of the catheter tip in the portal vein was performed with a technique designed to avoid portal thrombosis and infections. Permanent portal vein access in a rodent model of liver metastases will be invaluable for the development of novel therapeutic strategies.     

Improved technique of portal vein reconstruction in pediatric liver transplant recipients with portal vein hypoplasia

BACKGROUND: Children with small or hypoplastic portal veins represent a challenge for liver transplantation. Graft loss of up to 70% has been reported in these patients in the past. A variety of techniques has been used in both cadaveric and living related transplants in an effort to overcome this problem. Variability arises as to whether to use a vascular graft and where on the portal system to attach the graft. METHOD: We present our usage of a simple and straightforward interposition iliac vein allograft fashioned in a manner to achieve large anastomotic cross-sectional area on the confluence of the superior mesenteric/splenic veins. The procedure also overcomes problems of graft vein/portal vein size mismatch in the cases where liver and vein grafts are procured from much larger donors. RESULTS: A total of 14 children presented with hypoplastic portal vein (diameter<5 mm), of a total of 30 consecutive patients requiring cadaveric liver transplants, and benefited from this technique. Median recipient age was 10.5 months. Revascularization times ranged from 22 to 43 min with a mean of 33 min. All patients are alive and well at a mean follow-up of 329 days (10 months). All liver grafts are well and functioning. No portal vein problem was detected. CONCLUSION: Results from this technique are clearly encouraging. Because portal vein hypoplasia is a common problem in pediatric transplant candidates, we believe this alternative technique is of interest and should be added to the transplant surgeon's armamentarium.     

Renoportal anastomosis in right lobe living donor liver transplantation: report of a case

End-stage liver disease is often accompanied by thrombosis of the portal vein and the formation of splanchnic collateral vessels. Successful liver transplantation in such situations is more likely if the surgeon uses a strategy to establish a graft inflow. A 59-year-old male with a decompensated liver secondary to idiopathic portal hypertension underwent living donor liver transplantation (LDLT) using a right lobe liver graft donated from his son. His portal venous trunk was atrophied and a splenorenal shunt drained the mesenteric venous flow into the systemic circulation. LDLT was performed with renoportal anastomosis (RPA) using his right internal jugular vein as an interposed venous graft, without dissecting the collateral vessels. Although he developed temporary functional hyperbilirubinemia, he was discharged from the hospital 23 days after LDLT. This case suggests that RPA is a useful technique to manage patients with an obstructed portal vein and a splenorenal shunt.     

Hepatocyte transplantation through the hepatic vein: a new route of cell transplantation to the liver

The efficiency of hepatocyte transplantation into the liver varies with the method of administration. This study investigated whether retrograde infusion via the hepatic vein provides a sufficient number of donor cells for the liver. Donor hepatocytes were isolated from dipeptidyl peptidase IV (DPPIV(+)) rats and transplanted into DPPIV(-) rat livers either by antegrade portal vein infusion or retrograde hepatic vein infusion. Hepatocyte engraftment ratios and localization were evaluated by histological DPPIV enzymatic staining at 1 week and 8 weeks after the transplantation. No significant differences in engraftment efficiency were observed at either 1 week or 8 weeks after transplantation by either route. However, the localization of the transplanted hepatocytes differed with the administration route. Portal vein infusion resulted in predominantly periportal engraftment, whereas hepatic vein infusion led to pericentral zone engraftment. Immunohistochemical analysis showed that the transplanted hepatocytes engrafted in the pericentral zone after retrograde infusion displayed intense CYP2E1 staining similar to the surrounding native hepatocytes. CYP2E1 staining was further enhanced by administration of isosafrole, an inducing agent for various cytochrome P450 enzymes, including CYP2E1. This study demonstrates a novel approach of transplanting hepatocytes into the liver through retrograde hepatic vein infusion as the means to target cell implantation to the pericentral zone.     

A simple and effective method to improve intrasplenic rat hepatocyte transplantation

Transplanted hepatocytes integrate, survive, and express their specific functions in the liver parenchyma. The aim of this study was to determine whether a large number of hepatocytes could move from the spleen to the liver when the cells are injected together with sodium nitroprusside, and if the improved hepatocyte migration may be related with portal vein dilatation. Wistar rats were transplanted in the spleen with fluorescent-labeled hepatocytes alone or together with sodium nitroprusside. At 1, 3, 6, and 24 h after the transplant, the liver from recipient animals was removed and morphometric analyses were performed. Portal and arterial pressures were also measured immediately after intrasplenic injection of a solution of sodium nitroprusside, hepatocytes alone, or hepatocytes plus sodium nitroprusside. Intrasplenically injected sodium nitroprusside produced a transient drop in arterial pressure and a sustained reduction in portal pressure. During hepatocyte transplantation it increased the number of transplanted cells migrating to the liver after 3 h. Sodium nitroprusside simultaneously injected with hepatocytes in the spleen allowed more cells to migrate into the liver of the host animal without risk in animal survival.