Liver regeneration following experimental major hepatectomy with choledochojejunostomy

Validation study of postoperative liver failure and mortality risk scores after liver resection for perihilar cholangiocarcinoma

BACKGROUND

Surgery for perihilar cholangiocarcinoma (PHCC) remains a challenging procedure with high morbidity and mortality. The Academic Medical Center (Amsterdam UMC) and Memorial Sloan Kettering Cancer Center proposed a postoperative mortality risk score (POMRS) and post-hepatectomy liver failure score (PHLFS) to predict patient outcomes. This study aimed to validate the POMRS and PHLFS for PHCC patients at Hokkaido University.

METHODS

Medical records of 260 consecutive PHCC patients who had undergone major hepatectomy with extrahepatic bile duct resection without pancreaticoduodenectomy at Hokkaido University between March 2001 and November 2018 were evaluated to validate the PHLFS and POMRS.

RESULTS

The observed risks for PHLF were 13.7%, 24.5%, and 39.8% for the low-risk, intermediate-risk, and high-risk groups, respectively, in the study cohort. A receiver-operator characteristic (ROC) analysis revealed that the PHLFS had moderate predictive value, with an analysis under the curve (AUC) value of 0.62. Mortality rates based on the POMRS were 1.7%, 5%, and 5.1% for the low-risk, intermediate-risk, and high-risk groups, respectively. The ROC analysis demonstrated an AUC value of 0.58.

CONCLUSIONS

This external validation study showed that for PHLFS the threshold for discrimination in an Eastern cohort was reached (AUC >0.6), but it would require optimization of the model before use in clinical practice is acceptable. The POMRS were not applicable in the eastern cohort. Further external validation is recommended.

Re-thinking of T-tube use in whole liver transplantation: an analysis on the risk of delayed graft function

The liver-gut axis has been identified as crucial mediator of liver regeneration. Thus, the use of a T-tube in liver transplantation (LT), which interrupts the enterohepatic bile circulation, may potentially have a detrimental effect on the early allograft functional recovery. We retrospectively analyzed a cohort of 261 patients transplanted with a whole liver graft, with a duct-to-duct biliary anastomosis, who did not develop any surgical complication within postoperative day 14. Early allograft dysfunction (EAD) was defined according to the criteria of Olthoff et al. (EAD-O), and graded according to the Model for Early Allograft Function (MEAF) score. EAD-O developed in 24.7% of recipients and the median MEAF score was 4.0 [interquartile range 2.9-5.5]. Both MEAF and EAD predicted 90-day post-LT mortality. A T-tube was used in 49.4% of cases (n = 129). After a propensity score matching for donor age, cold and warm ischemia time, donor risk index, balance of risk score, Child-Pugh class C, and MELD score, the T-tube group showed a significantly higher prevalence of EAD-O and value of MEAF than the no-T-tube group (EAD-O: 29 [34.1%] vs 16 [19.0%], p = 0.027; MEAF 4.5 [3.5-5.7] vs 3.7 [2.9-5.0], p = 0.014). In conclusion, T-tube use in LT may be a risk factor for EAD and higher MEAF, irrespective of graft quality and severity of pre-LT liver disease.

Liver Regeneration after Hepatectomy and Partial Liver Transplantation

The liver is a unique organ with an abundant regenerative capacity. Therefore, partial hepatectomy (PHx) or partial liver transplantation (PLTx) can be safely performed. Liver regeneration involves a complex network of numerous hepatotropic factors, cytokines, pathways, and transcriptional factors. Compared with liver regeneration after a viral- or drug-induced liver injury, that of post-PHx or -PLTx has several distinct features, such as hemodynamic changes in portal venous flow or pressure, tissue ischemia/hypoxia, and hemostasis/platelet activation. Although some of these changes also occur during liver regeneration after a viral- or drug-induced liver injury, they are more abrupt and drastic following PHx or PLTx, and can thus be the main trigger and driving force of liver regeneration. In this review, we first provide an overview of the molecular biology of liver regeneration post-PHx and -PLTx. Subsequently, we summarize some clinical conditions that negatively, or sometimes positively, interfere with liver regeneration after PHx or PLTx, such as marginal livers including aged or fatty liver and the influence of immunosuppression.

Issues to be considered to address the future liver remnant prior to major hepatectomy

An accurate preoperative evaluation of the hepatic function and application of portal vein embolization in selected patients have helped improve the safety of major hepatectomy. In planning major hepatectomy, however, several issues remain to be addressed. The first is which cut-off values for serum total bilirubin level and prothrombin time should be used to define post-hepatectomy liver failure. Other issues include what minimum future liver remnant (FLR) volume is required; whether the total liver volume measured using computed tomography or the standard liver volume calculated based on the body surface area should be used to assess the adequacy of the FLR volume; whether there is a discrepancy between the FLR volume and function during the recovery period after portal vein embolization or hepatectomy; and how best the function of a specific FLR can be assessed. Various studies concerning these issues have been reported with controversial results. We should also be aware that different strategies and management are required for different types of liver damage, such as cirrhosis in hepatocellular carcinoma, cholangitis in biliary tract cancer, and chemotherapy-induced hepatic injury.

Potential Crosstalk between Liver and Extra-liver Organs in Mouse Models of Acute Liver Injury

Carbon tetrachloride (CCl4), Concanavalin A (ConA), bile duct ligation (BDL), and liver resection (LR) are four types of commonly used mouse models of acute liver injury. However, these four models belong to different types of liver cell damage while their application situations are often confounded. In addition, the systematic changes of multiple extra-liver organs after acute liver injury and the crosstalk between liver and extra-liver organs remain unclear. Here, we aim to map the morphological, metabolomic and transcriptomic changes systematically after acute liver injury and search for the potential crosstalk between the liver and the extra-liver organs. Significant changes of transcriptome were observed in multiple extra-liver organs after different types of acute liver injury despite dramatic morphological damage only occurred in lung tissues of the ConA/BDL models and spleen tissues in the ConA model. Liver transcriptomic changes initiated the serum metabolomic alterations which correlated to transcriptomic variation in lung, kidney, and brain tissues of BDL and LR models. The potential crosstalk might lead to pulmonary damage and development of hepatorenal syndrome (HRS) and hepatic encephalopathy (HE) during liver injury. Serum derived from acute liver injury mice damaged alveolar epithelial cells and human podocytes in vitro. Our data indicated that different types of acute liver injury led to different transcriptomic changes within extra-liver organs. Integration of serum metabolomics and transcriptomics from multiple tissues can improve our understanding of acute liver injury and its effect on the other organs.

The Impact of Biliary Reconstruction Methods on Small Partial Liver Grafts

Supplemental Digital Content is available in the text.

Graft recipient weight ratios are lower in adult-to-adult living-donor liver transplantation than in adult-to-adult deceased-donor liver transplantation. Rapid liver regeneration is essential for increased recipient survival rates in adult-to-adult living-donor liver transplantation. However, the influence of biliary reconstruction methods, including choledocho-choledochostomy and choledocho-jejunostomy, on small partial liver grafts remains unknown. Herein, we investigate the impact of these biliary reconstruction methods on small partial liver grafts.

Therapeutic targets for liver regeneration after acute severe injury: a preclinical overview

Introduction: Liver transplantation is the only viable treatment with a proven survival benefit for acute liver failure (ALF). Donor organ shortage is, however, a major hurdle; hence, alternative approaches that enable liver regeneration and target acute severe hepatocellular damage are necessary.Areas covered: This article sheds light on therapeutic targets for liver regeneration and considers their therapeutic potential. ALF following extensive hepatocyte damage and small-for-size syndrome (SFSS) are illuminated for the reader while the molecular mechanisms of liver regeneration are assessed in accordance with relevant therapeutic strategies. Furthermore, liver background parameters and predictive biomarkers that might associate with liver regeneration are reviewed.Expert opinion: There are established and novel experimental strategies for liver regeneration to prevent ALF resulting from SFSS. Granulocyte-colony stimulating factor (G-CSF) is a promising agent targeting liver regeneration after acute severe injury. Autophagy and hepatocyte senescence represent attractive new targets for liver regeneration in acute severe hepatic injury. Liver support strategies, including tissue engineering, constitute novel regenerative means; the success of this is dependent on stem cell research advances. However, there is no firm clinical evidence that these supportive strategies may alleviate hepatocellular damage until liver transplantation becomes available or successful self-liver regeneration occurs.

Discrepancy between volume and functional recovery in early phase liver regeneration following extended hepatectomy with extrahepatic bile duct resection

AIM

To elucidate the clinical factors having an impact on liver regeneration rate following preoperative portal vein embolization (PVE) and subsequent extended hepatectomy. The correlation between liver volume and functional recovery after extended hepatectomy was also investigated.

METHODS

Records of patients who underwent extended hepatectomy with extrahepatic bile duct resection following PVE for perihilar cholangiocarcinoma were reviewed retrospectively with attention to liver regeneration. All patients underwent computed tomography before PVE, after PVE (immediately before surgery), and on postoperative day (POD) 7. The kinetic growth rate (KGR) was calculated as the percent increase in liver volume relative to the future liver remnant volume per day after PVE (KGR_PVE ) and after POD 7 (KGR_POD7 ) using the computed tomography images before PVE, after PVE, and on POD 7.

RESULTS

In the 289 study patients, the median of KGR_PVE was 1.35%/day whereas that of KGR_POD7 was 5.56%/day. The extent of liver resection had the greatest impact on both KGR_PVE and KGR_POD7 and the impacts of other factors were less. There was a significant negative correlation between KGR_PVE and KGR_POD7 (P = 0.002). No correlations were observed between KGR_PVE or KGR_POD7 and serum total bilirubin and prothrombin time - international normalized ratio on POD 7, nor in the incidence of liver failure after surgery.

CONCLUSIONS

Early phase liver regeneration after extended hepatectomy was largely influenced by the extent of liver resection and showed no correlation with the indices of liver failure. There was a discrepancy between volume and functional recovery in early phase liver regeneration.

Advanced hilar cholangiocarcinoma: An aggressive surgical approach for the treatment of advanced hilar cholangiocarcinoma: Perioperative management, extended procedures, and multidisciplinary approaches

Hilar cholangiocarcinoma is a highly intractable malignancy. One of the reasons for its intractability is that most patients with the disease are diagnosed with an advanced stage of the disease at their initial presentation. Surgical resection is the standard therapy for hilar cholangiocarcinoma, providing a chance for a cure, and an aggressive surgical approach substantially increases the number of resectable tumors that are initially regarded as unresectable tumors. The success and standardization of the aggressive approach is warranted by meticulous preoperative management that prevents fatal postoperative complications. Extended resection procedures, including hepatic trisectionectomy for Bismuth type IV tumors, hepatopancreaticoduodenectomy for tumors with extensive longitudinal tumor spreading, and combined vascular resection with reconstruction for tumors with the involvement of hepatic vascular structures, have been challenged to expand the surgical indication. Due to acceptable surgical/survival outcomes, the three extended procedures are currently regarded as extended but standard options in specialized hepatobiliary centers. Although it remains a controversial multidisciplinary approach, the combination of these extended procedures with an adjuvant/neoadjuvant treatment is a promising approach for further improving the resectability of tumors and the survival of patients.

Clinical Significance of Preoperative Serum CEA, CA125, and CA19-9 Levels in Predicting the Resectability of Cholangiocarcinoma

To explore the clinical significance of preoperative serum CEA, CA125, and CA19-9 levels in predicting the resectability of cholangiocarcinoma. Patients with cholangiocarcinoma diagnosed by radiologic examination and admitted to the Second Affiliated Hospital of Harbin Medical University from September 1, 2011, to November 30, 2017, were retrospectively included. The relationship between the preoperative serum CEA, CA125, and CA19-9 levels and the resectability of cholangiocarcinoma was analyzed by receiver operating characteristic (ROC) curve, as well as the best cut-off point. A total of 112 met the inclusion criteria. In 50 patients with radical surgeries, the levels of preoperative serums CEA, CA125, and CA19-9 were 5.0 ± 13.9 ng/mL, 15.3 ± 11.8 U/mL, and 257.5 ± 325.6 U/mL, respectively, which were lower than those in patients with unresectable tumor. Based on the ROC curve, the ideal CA19-9 cut-off value was determined to be 1064.1 U/mL in prediction of resectability, with a sensitivity of 53.2%, a specificity of 94.0%, and the area under the ROC curve of 0.73 (P < 0.05). The cut-off value of CA125 was 17.8 U/mL with a sensitivity of 72.6%, a specificity of 78.0%, and the area under the ROC curve of 0.81 (P < 0.05). The cut-off value of CEA was 2.6 ng/mL with a sensitivity of 79.0%, a specificity of 48.0%, and the area under the ROC curve of 0.66 (P < 0.05). In addition to this, we found that using the combination of three tumor markers could improve the value in predicting resectability of cholangiocarcinoma. In summary, this study suggested that the preoperative serum CEA, CA125, and CA19-9 levels can help predict the resectability of cholangiocarcinoma.

Postoperative Liver Failure Criteria for Predicting Mortality after Major Hepatectomy with Extrahepatic Bile Duct Resection

BACKGROUND

Post-hepatectomy liver failure (PHLF) is a serious complication after major hepatectomy with extrahepatic bile duct resection (Hx with EBDR) that may cause severe morbidity and even death. The purpose of this study was to compare several criteria systems as predictors of PHLF-related mortality following Hx with EBDR for perihilar cholangiocarcinoma (PHCC).

METHODS

The study cohort consisted of 222 patients who underwent Hx with EBDR for PHCC. We compared several criteria systems, including previously established criteria (the International Study Group of Liver Surgery (ISGLS) criterion; and the "50-50" criterion), and our institution's novel systems "Max T-Bili" defined as total bilirubin (T-Bili) >7.3 mg/dL during post-operative days (POD) 1-7, and the "3-4-50" criterion, defined as total bilirubin >4 mg/dL and prothrombin time <50% on POD #3.

RESULTS

Thirteen patients (5.8%) died from PHLF-related causes. The 3-4-50 criterion showed high positive predictive values (39.1%), the 3-4-50, Max T-Bili, and 50-50 criterion showed high accuracies (91.7, 86.9, and 90.5%, respectively) and varying sensitivities (69.2, 69.2, and 38.5% respectively).

CONCLUSIONS

The 3-4-50, Max T-Bili, and 50-50 criterion were all useful for predicting PHLF-related mortality after Hx with EBDR for PHCC.

A simple rat model of in situ reversible obstructive jaundice in situ reversible obstructive jaundice model

PURPOSE

To develop a simple and reliable rat model of in situ reversible obstructive jaundice with low morbidity and mortality rates.

METHODS

Rats were divided into 4 groups with 8 rats each: the sham-operated (SH) group only underwent laparotomy, the control internal drainage (ID-C) group underwent choledochoduodenostomy, the new internal drainage (ID-N) group and the long-term internal drainage (ID-L) group underwent choledochocholedochostomy. Common bile duct ligation was performed in all the drainage groups 7 days before reversal procedures. All rats were sacrificed for samples 7 days after the last operation except rats of the ID-L group that survived 28 days before sacrifice. Body weight, liver function, histopathological changes, morbidity and mortality were assessed.

RESULTS

One rat died and 2 rats had complications with tube blockage in the ID-C group. No death or complications occurred in the ID-N and ID-L groups. The drainage tube remained patent in the long-term observation ID-L group. Body weight showed no significant difference between the ID-C and ID-N groups after 7 days drainage. Liver function was not fully recovered in the ID-C and ID-N groups after 7 days drainage, but statistical differences were only observed in the ID-C group compared with the SH and ID-L groups. Periportal inflammation and bile duct proliferation showed severer in the ID-C group than in the ID-N group.

CONCLUSION

The present study provided an efficient, simple, and reliable rat model that is especially suitable for long-term or consecutive studies of reversible obstructive jaundice.