Hepatocyte morphology and kinetics after portal vein embolization

The Guidelines for Percutaneous Transhepatic Portal Vein Embolization: English Version

Preoperative portal vein embolization is a beneficial option to reduce the risk of postoperative liver failure by promoting the growth of the future liver remnant. In particular, a percutaneous transhepatic procedure (percutaneous transhepatic portal vein embolization) has been developed as a less-invasive approach. Although percutaneous transhepatic portal vein embolization is widely recognized as a safe procedure, various complications, including rare but fatal adverse events, have been reported. Currently, there are no prospective clinical trials regarding percutaneous transhepatic portal vein embolization procedures and no standard guidelines for the PTPE procedure in Japan. As a result, various methods and various embolic materials are used in each hospital according to each physician's policy. The purpose of these guidelines is to propose appropriate techniques at present and to identify issues that should be addressed in the future for safer and more reliable percutaneous transhepatic portal vein embolization techniques.

Optimization of the future remnant liver: review of the current strategies in Europe

Liver resection still represent the treatment of choice for liver malignancies, but in some cases inadequate future remnant liver (FRL) can lead to post hepatectomy liver failure (PHLF) that still represents the most common cause of death after hepatectomy. Several strategies in recent era have been developed in order to generate a compensatory hypertrophy of the FRL, reducing the risk of post hepatectomy liver failure. Portal vein embolization, portal vein ligation, and ALLPS are the most popular techniques historically adopted up to now. The liver venous deprivation and the radio-embolization are the most recent promising techniques. Despite even more precise tools to calculate the relationship among volume and function, such as scintigraphy with ^99mTc-mebrofenin (HBS), no consensus is still available to define which of the above mentioned augmentation strategy is more adequate in terms of kind of surgery, complexity of the pathology and quality of liver parenchyma. The aim of this article is to analyse these different strategies to achieve sufficient FRL.

BestFLR Trial: Liver Regeneration at CT before Major Hepatectomies for Liver Cancer-A Randomized Controlled Trial Comparing Portal Vein Embolization with N-Butyl-Cyanoacrylate Plus Iodized Oil versus Polyvinyl Alcohol Particles Plus Coils

Background In patients with liver cancer, portal vein embolization (PVE) is recommended to promote liver growth before major hepatectomies. However, the optimal embolization strategy has not been established. Purpose To compare liver regeneration as seen at CT in participants with liver cancer, before major hepatectomies, with N-butyl-cyanoacrylate (NBCA) plus iodized oil versus standard polyvinyl alcohol (PVA) particles plus coils, for PVE. Materials and Methods In this single-center, prospective, randomized controlled trial (Best Future Liver Remnant, or BestFLR, trial; International Standard Randomized Controlled Trial Number 16062796), PVE with NBCA plus iodized oil was compared with standard PVE with PVA particles plus coils in participants with liver cancer. Participant recruitment started in November 2017 and ended in March 2020. Participants were randomly assigned to undergo PVE with PVA particles plus coils or PVE with NBCA plus iodized oil. The primary end point was liver growth assessed with CT 14 days and 28 days after PVE. Secondary outcomes included posthepatectomy liver failure, surgical complications, and length of intensive care treatment and hospital stay. The Mann-Whitney U test was used to compare continuous outcomes according to PVE material, whereas the Χ² test or Fisher exact test was used for categoric variables. Results Sixty participants (mean age, 61 years ± 11 [standard deviation]; 32 men) were assigned to the PVA particles plus coils group (n = 30) or to the NBCA plus iodized oil group (n = 30). Interim analysis revealed faster and superior liver hypertrophy for the NBCA plus iodized oil group versus the PVA particles plus coils group 14 days and 28 days after PVE (absolute hypertrophy of 46% vs 30% [P < .001] and 57% vs 37% [P < .001], respectively). Liver growth for the proposed hepatectomy was achieved in 87% of participants (26 of 30) in the NBCA plus iodized oil group versus 53% of participants (16 of 30) in the PVA particles plus coils group (P = .008) 14 days after PVE. Liver failure occurred in 13% of participants (three of 24) in the NBCA plus iodized oil group and in 27% of participants (six of 22) in the PVA particles plus coils group (P = .27). Conclusion Portal vein embolization with N-butyl-cyanoacrylate plus iodized oil produced greater and faster liver growth as seen at CT in participants with liver cancer, compared with portal vein embolization with polyvinyl alcohol particles plus coils, allowing for earlier surgical intervention. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Arellano in this issue.

Preoperative biliary drainage of the hepatic lobe to be resected does not affect liver hypertrophy after percutaneous transhepatic portal vein embolization

BACKGROUND

In patients with malignant perihilar biliary strictures, preoperative biliary drainage (PBD) of the hepatic lobe to be resected may decrease the liver volume of the future liver remnant (FLR) after percutaneous transhepatic portal vein embolization (PVE). However, evidence of its application is insufficient. This study aimed to clarify the effects of PBD on liver hypertrophy after PVE.

METHODS

Between January 2008 and December 2017, 169 patients with malignant perihilar biliary strictures underwent major hepatectomy or palliative surgery at our hospital. Of these, 76 patients who underwent PVE were categorized into two groups: group A (n = 29) who received unilateral PBD of the FLR and group B (n = 47) who received bilateral PBD, including that of the hepatic lobe to be resected. FLR ratios after PVE and liver hypertrophy ratios were retrospectively compared in both groups.

RESULTS

Group B exhibited significantly severe biliary stenosis (p = 0.0038) and high serum bilirubin before biliary drainage (p = 0.0037). After PVE, the total liver volumes were 1287 ± 260 ml and 1340 ± 257 ml (p = 0.39), respectively. FLR volumes were 555 ± 135 and 577 ± 113 ml (p = 0.45), respectively. FLR ratios were 43.4 ± 8.2% and 43.4 ± 6.4%, respectively (p = 0.98). Liver hypertrophy ratios were 124.2 ± 17.7% and 129.2 ± 20.9%, respectively (p = 0.28). In addition, an examination which excluded patients with Bismuth type I obtained similar result.

CONCLUSIONS

PBD of the hepatic lobe to be resected did not decrease the FLR ratios and hypertrophy ratios. Thus, in patients with poor biliary drainage, additional PBD of the target lobe is acceptable.

Bioenergetic adaptations of the human liver in the ALPPS procedure - how liver regeneration correlates with mitochondrial energy status

BACKGROUND

The Associating Liver Partition and Portal Ligation for Staged Hepatectomy (ALPPS) depends on a significant inter-stages kinetic growth rate (KGR). Liver regeneration is highly energy-dependent. The metabolic adaptations in ALPPS are unknown.

AIMS

i) Assess bioenergetics in both stages of ALPPS (T1 and T2) and compare them with control patients undergoing minor (miHp) and major hepatectomy (MaHp), respectively; ii) Correlate findings in ALPPS with volumetric data; iii) Investigate expression of genes involved in liver regeneration and energy metabolism.

METHODS

Five patients undergoing ALPPS, five controls undergoing miHp and five undergoing MaHp. Assessment of remnant liver bioenergetics in T1, T2 and controls. Analysis of gene expression and protein content in ALPPS.

RESULTS

Mitochondrial function was worsened in T1 versus miHp; and in T2 versus MaHp (p < 0.05); but improved from T1 to T2 (p < 0.05). Liver bioenergetics in T1 strongly correlated with KGR (p < 0.01). An increased expression of genes associated with liver regeneration (STAT3, ALR) and energy metabolism (PGC-1α, COX, Nampt) was found in T2 (p < 0.05).

CONCLUSION

Metabolic capacity in ALPPS is worse than in controls, improves between stages and correlates with volumetric growth. Bioenergetic adaptations in ALPPS could serve as surrogate markers of liver reserve and as target for energetic conditioning.

Liver atrophy after percutaneous transhepatic portal embolization occurs in two histological phases: Hepatocellular atrophy followed by apoptosis

AIM

To clarify the histological changes associated with liver atrophy after percutaneous transhepatic portal embolization (PTPE) in pigs and humans.

METHODS

As a preliminary study, we performed pathological examinations of liver specimens from five pigs that had undergone PTPE in a time-dependent model of liver atrophy. In specimens from embolized lobes (EMB) and nonembolized lobes (controls), we measured the portal vein to central vein distance (PV-CV), the area and number of hepatocytes per lobule, and apoptotic activity using the terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. Immunohistochemical reactivities were evaluated for light chain 3 (LC3) and lysosomal-associated membrane protein 2 (LAMP2) as autophagy markers and for glutamine synthetase and cytochrome P450 2E1 (CYP2E1) as metabolic zonation markers. Samples from ten human livers taken 20-36 d after PTPE were similarly examined.

RESULTS

PV-CVs and lobule areas did not differ between EMB and controls at day 0, but were lower in EMB than in controls at weeks 2, 4, and 6 (P ≤ 0.001). Hepatocyte numbers were not significantly reduced in EMB at day 0 and week 2 but were reduced at weeks 4 and 6 (P ≤ 0.05). Apoptotic activity was higher in EMB than in controls at day 0 and week 4. LC3 and LAMP2 staining peaked in EMB at week 2, with no significant difference between EMB and controls at weeks 4 and 6. Glutamine synthetase and CYP2E1 zonation in EMB at weeks 2, 4, and 6 were narrower than those in controls. Human results were consistent with those of porcine specimens.

CONCLUSION

The mechanism of liver atrophy after PTPE has two histological phases: Hepatocellular atrophy is likely caused by autophagy in the first 2 wk and apoptosis thereafter.

Preoperative Left Portal Vein Embolization for Left Liver Resection in High-Risk Hepatobiliary Malignancy Patients

BACKGROUND

Preoperative portal vein embolization (PVE) is performed for right liver (RL) and sometimes left liver (LL) resection to prevent postoperative surgical complications.

METHODS

We retrospectively reviewed 10 patients who underwent preoperative left PVE before LL resection for hepatobiliary malignancies along with 3 propensity score-matched control groups (n = 40 each).

RESULTS

Mean patient age was 68.6 ± 6.9 years. Diagnoses included intrahepatic cholangiocarcinoma (n = 4), perihilar cholangiocarcinoma (n = 3), neuroendocrine carcinoma (n = 1), recurrent cholangiocarcinoma (n = 1), and inflammatory liver mass (n = 1). The reason for left PVE was a large LL >40 % of the total liver volume (TLV) with a major comorbidity or age > 70 years with a poor overall condition. All patients underwent preplanned operations, including LL resection at 1-3 weeks post PVE. The LL volume proportion of the TLV was 44.9 ± 1.7 and 40.7 ± 2.3 % before and after PVE; thus, 1-2 weeks post PVE, the kinetic shrinkage rate of the LL was 9.4 ± 3.3 %, and the kinetic growth rate of the RL was 7.6 ± 2.7 %. The overall surgical complication rates were 40, 50, and 39.2 % in the left PVE, large LL control, and all three control groups, respectively (p ≥ 0.727). In contrast, the adjusted rates of major complications were 0 % in the left PVE group versus 36.8 % (p = 0.040), 25.6 % (p = 0.123), and 15.8 % (p = 0.295) in the large-, medium-, and small-sized LL control groups, respectively.

CONCLUSIONS

Our experience indicates that left PVE is safe and induces atrophy of the LL effectively. We suggest that it can be a useful option to reduce the risk of postoperative complications in elderly high-risk patients.

Thrombospondin-1 expression may be implicated in liver atrophic mechanism due to obstructed portal venous flow

AIM

Liver is an amazing organ that can undergo regenerative and atrophic changes inversely, depending on blood flow conditions. Although the regenerative mechanism has been extensively studied, the atrophic mechanism remains to be elucidated.

METHODS AND RESULTS

To assess the molecular mechanism of liver atrophy due to reduced portal blood flow, we analyzed the gene expressions between atrophic and hypertrophic livers induced by portal vein embolization in three human liver tissues using microarray analyses. Thrombospondin (TSP)-1 is an extracellular protein and a negative regulator of liver regeneration through its activation of the transforming growth factor-β/Smad signaling pathway. TSP-1 was extracted as the most upregulated gene in atrophic liver compared to hypertrophic liver due to portal flow obstruction in human. Liver atrophic and hypertrophic changes were confirmed by HE and proliferating cell nuclear antigen staining and terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling. In an in vivo model with portal ligation, TSP-1 and phosphorylated Smad2 expression were continuously induced at 6 h and thereafter in the portal ligated liver, whereas the induction was transient at 6 h in the portal non-ligated liver. Indeed, while cell proliferation represented by proliferating cell nuclear antigen expression at 48 h was induced in the portal ligated liver, the sinusoidal dilatation and hepatocyte cell death with terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling was detectable at 48 h in the portal ligated liver.

CONCLUSIONS

Obstructed portal flow induces persistent TSP-1 expression and transforming growth factor-β/Smad signal activation in atrophic liver. Thrombospondin-1 may be implicated in the liver atrophic change due to obstructed portal flow as a pro-atrophic factor.

Preoperative Sequential Portal and Hepatic Vein Embolization in Patients with Hepatobiliary Malignancy

BACKGROUND

Preoperative portal vein embolization (PVE) induces shrinkage of the embolized lobe and compensatory regeneration in the non-embolized lobe, but does not always induce sufficient regeneration of the future remnant liver (FRL). We previously developed preoperative sequential PVE-hepatic vein embolization (HVE), and here we present our experience of treating 42 patients with sequential PVE-HVE.

METHODS

During 8-year study period, preoperative PVE-HVE was performed on 42 patients with hepatobiliary malignancies.

RESULTS

Primary diseases were bile duct cancers [perihilar cholangiocarcinoma (n = 33) and diffuse bile duct cancer (n = 1)], hepatocellular carcinomas (n = 4), and intrahepatic tumors [intrahepatic cholangiocarcinoma (n = 3) and gallbladder cancer liver invasion (n = 1)]. These patients demonstrated insufficient FRL regeneration following PVE, thus HVE was performed to induce further regeneration. No PVE-HVE procedure-associated complications occurred. In the bile duct cancer group, FRL volume was 33.9 ± 2.2 % before PVE, 38.4 ± 1.5 % before HVE, 43.7 ± 2.1 % at surgery, and 73.6 ± 8.3 % at 2 weeks after right hepatectomy. The degree of FRL hypertrophy was 13.3 % after PVE, 28.9 % after PHV-HVE, and 117.1 % at 2 weeks after right hepatectomy. All patients except one recovered uneventfully after surgery, and the 3-year patient survival rate was 45.1 %. In the HCC group, transarterial chemoembolization was initially performed and FRL regeneration following PVE-HVE occurred very slowly. Active FRL regeneration occurred in the liver tumor group, but rapid tumor growth was observed in 1 of 4 patients.

CONCLUSION

The sequential application of HVE following PVE safely and effectively induces further FRL regeneration in non-cirrhotic livers. Further validation using larger patient population and multicenter studies is needed to reliably widen the indications.

Improved liver function after portal vein embolization and an elective right hepatectomy

BACKGROUND

Portal vein embolization (PVE) is used before extensive hepatic resections to increase the volume of the future remnant liver within acceptable safety margins (conventionally >0.6% of the patient's weight). The objective was to determine whether pre-operative PVE impacts on post-operative liver function independently from the increase in liver volume.

METHODS

The post-operative liver function of patients who underwent an anatomical right liver resection with (n = 28) and without (n = 53) PVE were retrospectively analysed. Donors of the right liver were also analysed (LD) (n = 17).

RESULTS

Patient characteristics were similar, except for age, weight and American Society of Anesthesiologists (ASA) score that were lower in LD. Post-operative factor V and bilirubin levels were, respectively, higher and lower in patients with PVE compared with patients without PVE or LD (P < 0.05). Patients with PVE had an increased blood loss, blood transfusions and sinusoidal obstruction syndrome. The day-3 bilirubin level was 40% lower in the PVE group compared with the no-PVE group after adjustment for body weight, chemotherapy, operating time, Pringle time, blood transfusions, remnant liver volume, pre-operative bilirubin level and pre-operative prothrombin ratio (P = 0.001).

CONCLUSIONS

For equivalent volumes, the immediate post-operative hepatic function appears to be better in livers prepared with PVE than in unprepared livers. Future studies should analyse whether the conventional inferior volume limit that allows a safe liver resection may be lowered when a PVE is performed.

A comparison of portal vein embolization with poly(2-hydroxyethylmethacrylate) and a histoacryl/lipiodol mixture in patients scheduled for extended right hepatectomy

To determine whether PHEMA [poly(2-hydroxyethylmethacrylate)] is suitable for portal vein embolization in patients scheduled to right hepatectomy and whether it is as effective as the currently used agent (a histoacryl/lipiodol mixture). Two groups of nine patients each scheduled for extended right hepatectomy for primary or secondary hepatic tumor, had right portal vein embolization in an effort to induce future liver remnant (FLR) hypertrophy. One group had embolization with PHEMA, the other one with the histoacryl/lipiodol mixture. In all patients, embolization was performed using the right retrograde transhepatic access. Embolization was technically successful in all 18 patients, with no complication related to the embolization agent. Eight patients of either group developed FLR hypertrophy allowing extended right hepatectomy. Likewise, one patient in each group had recanalization of a portal vein branch. Histology showed that both embolization agents reach the periphery of portal vein branches, with PHEMA penetrating somewhat deeper into the periphery. PHEMA has been shown to be an agent suitable for embolization in the portal venous system comparable with existing embolization agent (histoacryl/lipiodol mixture).

Preoperative estimation of future remnant liver function following portal vein embolization using relative enhancement on gadoxetic acid disodium-enhanced magnetic resonance imaging

Objective

To retrospectively evaluate relative enhancement (RE) in the hepatobiliary phase of gadoxetic acid disodium-enhanced magnetic resonance (MR) imaging as a preoperative estimation of future remnant liver (FRL) function in a patients who underwent portal vein embolization (PVE).

Materials and Methods

In 53 patients, the correlation between the indocyanine green clearance (ICG-K) and RE imaging was analyzed before hepatectomy (first analysis). Twenty-three of the 53 patients underwent PVE followed by a repeat RE imaging and ICG test before an extended hepatectomy and their results were further analyzed (second analysis). Whole liver function and FRL function were calculated on the MR imaging as follows: RE x total liver volume (RE Index) and FRL-RE x FRL volume (Rem RE Index), respectively. Regarding clinical outcome, posthepatectomy liver failure (PHLF) was evaluated in patients undergoing PVE.

Results

Indocyanine green clearance correlated with the RE Index (r = 0.365, p = 0.007), and ICG-K of FRL (ICG-Krem) strongly correlated with the Rem RE Index (r = 0.738, p < 0.001) in the first analysis. Both the ICG-Krem and the Rem RE Index were significantly correlated after PVE (r = 0.508, p = 0.013) at the second analysis. The rate of improvement of the Rem RE Index from before PVE to after PVE was significantly higher than that of ICG-Krem (p = 0.014). Patients with PHLF had a significantly lower Rem RE Index than patients without PHLF (p = 0.023).

Conclusion

Relative enhancement imaging can be used to estimate FRL function after PVE.

Clinical practice guidelines for the management of biliary tract cancers 2015: the 2nd English edition

BACKGROUND

The Japanese Society of Hepato-Biliary-Pancreatic Surgery launched the clinical practice guidelines for the management of biliary tract and ampullary carcinomas in 2008. Novel treatment modalities and handling of clinical issues have been proposed after the publication. New approaches for editing clinical guidelines, such as the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system, also have been introduced for better and clearer grading of recommendations.

METHODS

Clinical questions (CQs) were proposed in seven topics. Recommendation, grade of recommendation and statement for each CQ were discussed and finalized by evidence-based approach. Recommendation was graded to grade 1 (strong) and 2 (weak) according to the concept of GRADE system.

RESULTS

The 29 CQs covered seven topics: (1) prophylactic treatment, (2) diagnosis, (3) biliary drainage, (4) surgical treatment, (5) chemotherapy, (6) radiation therapy, and (7) pathology. In 27 CQs, 19 recommendations were rated strong and 11 recommendations weak. Each CQ included the statement of how the recommendation was graded.

CONCLUSIONS

This guideline provides recommendation for important clinical aspects based on evidence. Future collaboration with cancer registry will be a key for assessment of the guidelines and establishment of new evidence. Free full-text articles and a mobile application of this guideline are available via http://www.jshbps.jp/en/guideline/biliary-tract2.html.

Prognostic importance of some clinical and therapeutic factors for the effect of portal vein embolization in patients with primarily inoperable colorectal liver metastases

INTRODUCTION

Portal vein embolization (PVE) may increase the resectability of liver metastases. However, the problem of PVE is insufficient growth of the liver or tumor progression in some patients. The aim of this study was to evaluate the significance of commonly available clinical factors for the result of PVE.

MATERIAL AND METHODS

Portal vein embolization was performed in 38 patients with colorectal liver metastases. Effects of age, gender, time between PVE and liver resection, oncological therapy after PVE, indocyanine green retention rate test, synchronous, metachronous and extrahepatic metastases, liver volume before and after PVE, increase of liver volume after PVE and the quality of liver parenchyma before PVE on the result of PVE were evaluated.

RESULTS

Liver resection was performed in 23 (62.2%) patients within 1.3 ±0.4 months after PVE. Tumor progression occurred in 9 (23.7%) patients and 6 (15.8%) patients had insufficient liver hypertrophy. Significant clinical factors of PVE failure were number of liver metastases (cut-off - 4; odds ratio - 4.7; p < 0.03), liver volume after PVE (cut-off 1000 cm(3); odds ratio - 5.1; p < 0.02), growth of liver volume after PVE (cut-off 150 cm(3); odds ratio - 18.7; p < 0.002), oncological therapy administered concomitantly with PVE (p < 0.003).

CONCLUSIONS

Negative clinical factors of resectability of colorectal cancer liver metastases after PVE included more than four liver metastases, liver volume after PVE < 1000 cm(3), growth of the contralateral lobe by less than 150 cm(3) and concurrent oncological therapy.

31P MR spectroscopic imaging detects regenerative changes in human liver stimulated by portal vein embolization

PURPOSE

First, to evaluate hepatocyte phospholipid metabolism and energetics during liver regeneration stimulated by portal vein embolization (PVE) using proton-decoupled (31)P MR spectroscopic imaging ((31)P-MRSI). Second, to compare the biophysiologic differences between hepatic regeneration stimulated by PVE and by partial hepatectomy (PH).

MATERIALS AND METHODS

Subjects included six patients with hepatic metastases from colorectal cancer who were scheduled to undergo right PVE before definitive resection of right-sided tumor. (31)P-MRSI was performed on the left liver lobe before PVE and 48 h following PVE. Normalized quantities of phosphorus-containing hepatic metabolites were analyzed from both visits. In addition, MRSI data at 48 h following partial hepatectomy were compared with the data from the PVE patients.

RESULTS

At 48 h after PVE, the ratio of phosphomonoesters to phosphodiesters in the nonembolized lobe was significantly elevated. No significant changes were found in nucleoside triphosphates (NTP) and Pi values. The phosphomonoester (PME) to phosphodiester (PDE) ratio in regenerating liver 48 h after partial hepatectomy was significantly greater than PME/PDE 48 h after PVE.

CONCLUSION

(31)P-MRSI is a valid technique to noninvasively evaluate cell membrane metabolism following PVE. The different degree of biochemical change between partial hepatectomy and PVE indicates that hepatic growth following these two procedures does not follow the same course.

Liver regeneration and the atrophy-hypertrophy complex

The atrophy-hypertrophy complex (AHC) refers to the controlled restoration of liver parenchyma following hepatocyte loss. Different types of injury (e.g., toxins, ischemia/reperfusion, biliary obstruction, and resection) elicit the same hypertrophic response in the remnant liver. The AHC involves complex anatomical, histological, cellular, and molecular processes. The signals responsible for these processes are both intrinsic and extrinsic to the liver and involve both physical and molecular events. In patients in whom resection of large liver malignancies would result in an inadequate functional liver remnant, preoperative portal vein embolization may increase the remnant liver sufficiently to permit aggressive resections. Through continued basic science research, the cellular mechanisms of the AHC may be maximized to permit curative resections in patients with potentially prohibitive liver function.

Isolation and characterization of portal branch ligation-stimulated Hmga2-positive bipotent hepatic progenitor cells

Hepatic stem/progenitor cells are one of several cell sources that show promise for restoration of liver mass and function. Although hepatic progenitor cells (HPCs), including oval cells, are induced by administration of certain hepatotoxins in experimental animals, such a strategy would be inappropriate in a clinical setting. Here, we investigated the possibility of isolating HPCs in a portal branch-ligated liver model without administration of any chemical agents. A non-parenchymal cell fraction was prepared from the portal branch-ligated or non-ligated lobe, and seeded onto plates coated with laminin. Most of the cells died, but a small number were able to proliferate. These proliferating cells were cloned as portal branch ligation-stimulated hepatic cells (PBLHCs) by the limiting dilution method. The PBLHCs expressed cytokeratin19, albumin, and Hmga2. The PBLHCs exhibited metabolic functions such as detoxification of ammonium ions and synthesis of urea on Matrigel-coated plates in the presence of oncostatin M. In Matrigel mixed with type I collagen, the PBLHCs became rearranged into cystic and tubular structures. Immunohistochemical staining demonstrated the presence of Hmga2-positive cells around the interlobular bile ducts in the portal branch-ligated liver lobes. In conclusion, successful isolation of bipotent hepatic progenitor cell clones, PBLHCs, from the portal branch-ligated liver lobes of mice provides the possibility of future clinical application of portal vein ligation to induce hepatic progenitor cells.

Serum HGF and TGF-beta1 levels after right portal vein embolization

AIM

The changes in the serum hepatocyte growth factor (HGF) and transforming growth factor (TGF)-beta1 levels after portal vein embolization (PVE), and their clinical significance, remain unclear and we aimed to assess their relationship.

METHODS

The serum HGF and TGF-beta1 levels were prospectively measured in 22 patients before and 1, 3, 5, 7, and 14 day after right PVE. Computed tomographic volumetry was performed before and at a mean of 26 +/- 4 days after right PVE.

RESULTS

Three to four weeks after right PVE, the volume of embolized lobe significantly decreased from 704 +/- 157 cm(3) before PVE to 539 +/- 168 cm(3) after PVE (P < 0.001). In contrast, the volume of nonembolized lobe significantly increased from 426 +/- 142 cm(3) to 560 +/- 165 cm(3) (P < 0.001). The serum HGF level significantly increased on day 3 after PVE compared with the pretreatment level (P = 0.005), while the serum TGF-beta1 level significantly decreased and reached its lowest value on day 3 (P = 0.002). Using Pearson's correlation analysis, we found that the serum HGF and TGF-beta1 levels on day 14 negatively associated with the large hypertrophic response in the nonembolized lobe (HGF: r = -0.490, P = 0.021; TGF-beta1: r = -0.473, P = 0.026).

CONCLUSIONS

PVE induced an increase in the serum HGF level and reduced the serum TGF-beta1 level. Measurement of serum HGF and TGF-beta1 levels on day 14 after right PVE may be useful for assessment of the future liver hypertrophy in nonembolized lobe after right PVE.

Hepatic resection for large hepatocellular carcinoma in the era of UCSF criteria

BACKGROUND

Treating patients with hepatocellular carcinoma (HCC) remains a challenge, especially when the disease presents at an advanced stage. The aim of this retrospective study was to determine the efficacy of liver resection in patients who fulfil or exceed University of California San Francisco (UCSF) criteria by assessing longterm outcome.

METHODS

Between 2002 and 2008, 59 patients with large HCC (>5 cm) underwent hepatectomy. Thirty-two of these patients fulfilled UCSF criteria for transplantation (group A) and 27 did not (group B). Disease-free survival and overall survival rates were compared between the two groups after resection and were critically evaluated with regard to patient eligibility for transplant.

RESULTS

In all patients major or extended hepatectomies were performed. There was no perioperative mortality. Morbidity consisted of biliary fistula, abscess, pleural effusion and pneumonia and was significantly higher in patient group B. Disease-free survival rates at 1, 3 and 5 years were 66%, 37% and 34% in group A and 56%, 29% and 26% in group B, respectively (P < 0.01). Survival rates at 1, 3 and 5 years were 73%, 39% and 35% in group A and 64%, 35% and 29% in group B, respectively (P= 0.04). The recurrence rate was higher in group B (P= 0.002).

CONCLUSIONS

Surgical resection, if feasible, is suggested in patients with large HCC and can be performed with acceptable overall and disease-free survival and morbidity rates. In patients eligible for transplantation, resection may also have a place in the management strategy when waiting list time is prolonged for reasons of organ shortage or when the candidate has low priority as a result of a low MELD (model for end-stage liver disease) score.

Hepatic resection for hepatocellular carcinoma exceeding Milan criteria

BACKGROUND

Many hepatocellular carcinomas (HCCs) are discovered at an advanced stage. The efficacy of transplantation for such tumors is doubtable. The aim of this retrospective study was to determine liver resection efficacy in patients with large HCC regarding long term and disease- free survival.

METHODS

Between 2002 and 2008, sixty six patients with large HCC (>5cm) underwent hepatectomy. Fifty nine patients had background cirrhosis due to hepatitis B, C or other reason and preserved liver function (Child A). Liver function was assessed by both Child's-Pugh grading and MELD score. Conventional approach of liver resection was performed in most cases.

RESULTS

The 5-year overall survival was 32% with a median follow up of 33 months. The three year disease-free survival was 33% in our cohort. On multivariate analysis, only tumor size and grade remained independent predictors of adverse long term outcome. Multivariate analysis identified size of the primary tumour and degree of differentiation as risk factors for recurrence. Median blood loss was 540ml and median transfusion requirements were two units of pack red blood cells. Morbidity included pleural effusion (n=18), biliary fistula (n=4), peri-hepatic abscess (n=4), hyperbilirubinemia (n=3), pneumonia (n=5) and wound infection (n=6). No peri-operative mortality was reported in our study.

CONCLUSION

Partial hepatectomy is safe in selective patients with large HCC. Surgical resection if feasible is suggested in patients with large HCC because it prolongs both overall and disease-free survival with low morbidity.

Sequential preoperative ipsilateral hepatic vein embolization after portal vein embolization to induce further liver regeneration in patients with hepatobiliary malignancy

OBJECTIVE

To assess the effect of ipsilateral hepatic vein embolization (HVE) performed after portal vein embolization (PVE) on liver regeneration.

SUMMARY BACKGROUND DATA

PVE induces shrinkage of the embolized lobe and compensatory enlargement of the non-embolized lobe, but it does not always induce sufficient liver regeneration. There was no effective method to accelerate liver regeneration in addition to PVE yet.

METHODS

During a 1-year study period, preoperative HVE were performed on 12 patients who had shown limited liver regeneration after PVE awaiting right hepatectomy. The right hepatic vein was embolized with multiple coils after insertion of vena cava filters or vascular plugs.

RESULTS

No HVE procedure-related complications occurred, but embolization of the wrong hepatic vein trunk occurred in 1 patient. The increase in blood liver enzymes after HVE was comparable with that after PVE alone. In 9 patients who underwent hepatectomy, the proportions of future liver remnant volume to total liver volume were 34.8% +/- 1.5% before PVE, 39.7% +/- 0.6% 1 to 2 weeks after PVE, 44.2% +/- 1.1% 2 weeks after HVE, and 64.5% +/- 6.2% 1 week after right hepatectomy. Cirrhotic livers showed lower regeneration rates following HVE after PVE and 1 patient underwent hepatectomy 17 months after HVE. Immunohistochemistry showed that apoptosis occurred more in the liver area affected by both PVE and HVE than in that affected by PVE alone.

CONCLUSIONS

Preoperative sequential application of PVE and HVE seems to be safe and effective in facilitating contralateral liver regeneration by inducing more severe liver damage than PVE alone.

Hepatocellular carcinoma: Defining the place of surgery in an era of organ shortage

Liver resection (LR) and transplantation offer the only potential chance of cure for patients with hepatocellular carcinoma (HCC). Historically, all patients were treated by hepatic resection. With the advent of liver transplantation (LT) patients with HCC were preferentially placed on the waiting list for LT. However, early experience with LT was associated with a high rate of tumour recurrence and poor long-term survival. The increasing scarcity of donor livers resulted in restrictions being placed on tumour size, and an improvement in patient survival. To date there have been no randomised clinical trials comparing LR to LT. We review the evidence supporting LR and/or LT for HCC and discuss the role of neoadjuvant therapy. The decision of whether to resect or transplant remains debatable and is often determined by centre experience, availability of LT and donor organs.

Right portal vein ligation is as efficient as portal vein embolization to induce hypertrophy of the left liver remnant

BACKGROUND

Aim of this retrospective study was to compare induction of left liver hypertrophy after right portal vein ligation (PVL) and right portal vein embolization (PVE) before right hepatectomy for liver metastases.

MATERIALS AND METHODS

Between 1998 and 2005, 18 patients underwent a PVE, whereas 17 patients underwent a PVL during a first stage laparotomy.

RESULTS

There was no complication related to PVE or PVL. After a similar interval time (7 +/- 3 vs 8 +/- 3 weeks), the increase of the left liver volume was similar between the two groups (35 +/- 38 vs 38 +/- 26%). After PVE and PVL, right hepatectomy was performed in 12 and 14 patients, respectively. Technical difficulties during the right hepatectomy were similar according to duration of procedure (6.4 +/- 1 vs 6.7 +/- 1 h, p = 0.7) and transfusion rates (33 vs 28%, p = 0.7). Mortality was nil in both groups, and morbidity rates were respectively 58% for the PVE group and 36% for the PVL group (p = 0.6).

CONCLUSION

Right PVL and PVE result in a comparable hypertrophy of the left liver. During the first laparotomy of a two-step liver resection, PVL can be efficiently and safely performed.