Graft injury in relation to graft size in right lobe live donor liver transplantation: a study of hepatic sinusoidal injury in correlation with portal hemodynamics and intragraft gene expression

Development of a model to predict the risk of early graft failure after adult-to-adult living donor liver transplantation: An ELTR study

Graft survival is a critical end point in adult-to-adult living donor liver transplantation (ALDLT), where graft procurement endangers the lives of healthy individuals. Therefore, ALDLT must be responsibly performed in the perspective of a positive harm-to-benefit ratio. This study aimed to develop a risk prediction model for early (3 months) graft failure (EGF) following ALDLT. Donor and recipient factors associated with EGF in ALDLT were studied using data from the European Liver Transplant Registry. An artificial neural network classification algorithm was trained on a set of 2073 ALDLTs, validated using cross-validation, tested on an independent random-split sample (n=518), and externally validated on United Network for Organ Sharing Standard Transplant Analysis and Research data. Model performance was assessed using the AUC, calibration plots, and decision curve analysis. Graft type, graft weight, level of hospitalization, and the severity of liver disease were associated with EGF. The model ( http://ldlt.shinyapps.io/eltr_app ) presented AUC values at cross-validation, in the independent test set, and at external validation of 0.69, 0.70, and 0.68, respectively. Model calibration was fair. The decision curve analysis indicated a positive net benefit of the model, with an estimated net reduction of 5-15 EGF per 100 ALDLTs. Estimated risks>40% and<5% had a specificity of 0.96 and sensitivity of 0.99 in predicting and excluding EGF, respectively. The model also stratified long-term graft survival ( p <0.001), which ranged from 87% in the low-risk group to 60% in the high-risk group. In conclusion, based on a panel of donor and recipient variables, an artificial neural network can contribute to decision-making in ALDLT by predicting EGF risk.

"Reduced Size Liver Grafts in Pediatric Liver Transplantation; Technical Considerations"

Liver transplantation (LT) has become a vital treatment option for children with end-stage liver disease. Left lateral segment (LLS) grafts are particularly common in split and living donor LT for pediatric patients. However, challenges arise in small infants receiving LLS grafts, primarily due to graft-size mismatches, resulting in "large-for-size" grafts. To overcome this issue, the practice of further reducing grafts from the LLS to diminish graft thickness has been explored. Currently, the indication for reducing the thickness of LLS grafts includes recipients with a body weight (BW) under 5.0 kg, neonates with acute liver failure, or those with metabolic liver disease. At the National Center for Child Health and Development in Tokyo, Japan, among 131 recipients of reduced-size LLS grafts, a remarkable 15-year graft survival rate of 89.9% has been achieved in small infants. This success indicates that with experience and refinement of the technique, there's a trend towards improved graft survival in recipients with reduced-thickness LLS grafts. This advancement underscores the importance of BW-appropriate methods in graft selection to ensure exceptional outcomes in vulnerable pediatric patients in need of LT. These techniques' ongoing development and refinement are crucial in enhancing the survival rates and overall outcomes for these young patients.

Optimal graft size in pediatric living donor liver transplantation: How are children different from adults?

BACKGROUND

Pediatric liver transplantation is an established treatment for end-stage liver disease in children. However, it is still posing relevant challenges, such as optimizing the graft selection according to the recipient size. Unlike adults, small children tolerate large-for-size grafts and insufficient graft volume might represent an issue in adolescents when graft size is disproportionate.

METHODS

Graft-size matching strategies over time were examined in pediatric liver transplantation. This review traces the measures/principles put in place to prevent large-for-size or small-for-size grafts in small children to adolescents with a literature review and an analysis of the data issued from the National Center for Child Health and Development, Tokyo, Japan.

RESULTS

Reduced left lateral segment (LLS; Couinaud's segment II and III) was widely applicable for small children less than 5 kg with metabolic liver disease or acute liver failure. There was significantly worse graft survival if the actual graft-to-recipient weight ratio (GRWR) was less than 1.5% in the adolescent with LLS graft due to the small-for-size graft. Children, particularly adolescents, may then require larger GRWR than adults to prevent small-for-size syndrome. The suggested ideal graft selections in pediatric LDLT are: reduced LLS, recipient body weight (BW) < 5.0 kg; LLS, 5.0 kg ≤ BW < 25 kg; left lobe (Couinaud's segment II, III, IV with middle hepatic vein), 25 kg ≤ BW < 50 kg; right lobe (Couinaud's segment V, VI, VII, VIII without middle hepatic vein), 50 kg ≤ BW. Children, particularly adolescents, may then require larger GRWR than adults to prevent small-for-size syndrome.

CONCLUSION

Age-appropriate and BW-appropriate strategies of graft selection are crucial to secure an excellent outcome in pediatric living donor liver transplantation.

Post Living Donor Liver Transplantation Small-for-size Syndrome: Definitions, Timelines, Biochemical, and Clinical Factors for Diagnosis: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

BACKGROUND

When a partial liver graft is unable to meet the demands of the recipient, a clinical phenomenon, small-for-size syndrome (SFSS), may ensue. Clear definition, diagnosis, and management are needed to optimize transplant outcomes.

METHODS

A Consensus Scientific committee (106 members from 21 countries) performed an extensive literature review on specific aspects of SFSS, recommendations underwent blinded review by an independent panel, and discussion/voting on the recommendations occurred at the Consensus Conference.

RESULTS

The ideal graft-to-recipient weight ratio of ≥0.8% (or graft volume standard liver volume ratio of ≥40%) is recommended. It is also recommended to measure portal pressure or portal blood flow during living donor liver transplantation and maintain a postreperfusion portal pressure of <15 mm Hg and/or portal blood flow of <250 mL/min/100 g graft weight to optimize outcomes. The typical time point to diagnose SFSS is the postoperative day 7 to facilitate treatment and intervention. An objective 3-grade stratification of severity for protocolized management of SFSS is proposed.

CONCLUSIONS

The proposed grading system based on clinical and biochemical factors will help clinicians in the early identification of patients at risk of developing SFSS and institute timely therapeutic measures. The validity of this newly created grading system should be evaluated in future prospective studies.

Decoding Immune Signature to Detect the Risk for Early-Stage HCC Recurrence

Hepatocellular carcinoma (HCC) is often recognized as an inflammation-linked cancer, which possesses an immunosuppressive tumor microenvironment. Curative treatments such as surgical resection, liver transplantation, and percutaneous ablation are mainly applicable in the early stage and demonstrate significant improvement of survival rate in most patients. However, 70-80% of patients report HCC recurrence within 5 years of curative treatment, representing an important clinical issue. However, there is no effective recurrence marker after surgical and locoregional therapies, thus, tumor size, number, and histological features such as cancer cell differentiation are often considered as risk factors for HCC recurrence. Host immunity plays a critical role in regulating carcinogenesis, and the immune microenvironment characterized by its composition, functional status, and density undergoes significant alterations in each stage of cancer progression. Recent studies reported that analysis of immune contexture could yield valuable information regarding the treatment response, prognosis and recurrence. This review emphasizes the prognostic value of tumors associated with immune factors in HCC recurrence after curative treatment. In particular, we review the immune landscape and immunological factors contributing to early-stage HCC recurrence, and discuss the immunotherapeutic interventions to prevent tumor recurrence following curative treatments.

Small-For-Size Syndrome and Graft Inflow Modulation Techniques in Liver Transplantation

BACKGROUND

Partial liver transplantation has recently been proposed to alleviate organ shortages. However, transplantation of a small-for-size graft is associated with an increased risk of posttransplant hepatic dysfunction, commonly referred to as small-for-size syndrome (SFSS). This review describes the etiology, pathological features, clinical manifestations, and diagnostic criteria of SFSS. Moreover, we summarize strategies to improve graft function, focusing on graft inflow modulation techniques. Finally, unmet needs and future perspectives are discussed.

SUMMARY

In fact, posttransplant SFSS can be attributed to various factors such as preoperative status of the recipients, surgical techniques, donor age, and graft quality, except for graft size. With targeted improvement measures, satisfactory clinical outcomes can be achieved in recipients at increased risk of SFSS. Given the critical role of relative portal hyperperfusion in the pathogenesis of SFSS, various pharmacological and surgical treatments have been established to reduce or partially divert excessive portal inflow, and recipients will benefit from individualized therapeutic regimens after careful evaluation of benefits against potential risks. However, there remain unmet needs for further research into different aspects of SFSS to better understand the correlation between portal hemodynamics and patient outcomes.

KEY MESSAGES

Contemporary transplant surgeons should consider various donor and recipient factors and develop case-specific prevention and treatment strategies to improve graft and recipient survival rates.

Portocaval shunt can optimize transhepatic flow following extended hepatectomy: a short-term study in a porcine model

The aim of this study was to evaluate whether the portocaval shunt (PCS) corrects these unwanted changes in transhepatic flow after extended hepatectomy (EH). Forty female Landrace pigs were divided into two main groups: (A) EH (75%) and (B) no EH. Group A was divided into 3 subgroups: (A1) EH without PCS; (A2) EH with side-to-side PCS; and (A3) EH with end-to-side PCS. Group B was divided into 2 subgroups: (B1) side-to-side PCS and (B2) end-to-side PCS. HAF, PVF, and PVP were measured in each animal before and after the surgical procedure. EH increased the PVF/100 g (173%, p < 0.001) and PVP (68%, p < 0.001) but reduced the HAF/100 g (22%, p = 0.819). Following EH, side-to-side PCS reduced the increased PVF (78%, p < 0.001) and PVP (38%, p = 0.001). Without EH, side-to-side PCS reduced the PVF/100 g (68%, p < 0.001) and PVP (12%, p = 0.237). PVP was reduced by end-to-side PCS following EH by 48% (p < 0.001) and without EH by 21% (p = 0.075). PCS can decrease and correct the elevated PVP and PVF/100 g after EH to close to the normal values prior to resection. The decreased HAF/100 g in the remnant liver following EH is increased and corrected through PCS.

Do Natural Portosystemic Shunts Need to Be Compulsorily Ligated in Living Donor Liver Transplantation?

BACKGROUND

Natural portosystemic shunt ligation practices in liver transplant vary widely across transplant centres and are frequently undertaken to prevent the serious consequence of portal steal phenomenon. No concrete indications have so far been convincingly identified for their management in living donor liver transplant.

METHODS

We retrospectively studied the outcome of 89 cirrhotic patients who either did (n = 63) or did not (n = 25) undergo shunt ligation during living donor liver transplantation between 2017 and 2020.

RESULTS

The incidence of early allograft dysfunction/nonfunction (P = 1.0) and portal venous complications (P = 0.555) were similar between the two groups. Although overall complications, biliary complications, and the composite of Grade III and IV complications were significantly higher in the nonligated group (P = 0.015, 0.052 and 0.035), 1- year graft and patient survival were comparable between them (P = 0.524).

CONCLUSION

We conclude that shunt ligation in living donor liver transplantation may not always be necessary if adequate portal flow, good vascular reconstruction, and good graft quality have been ensured.

Ischemic-Free Liver Transplantation Reduces the Recurrence of Hepatocellular Carcinoma After Liver Transplantation

Ischemia reperfusion injury (IRI) is an adverse factor for hepatocellular carcinoma (HCC) recurrence after liver transplantation. Ischemic-free liver transplantation (IFLT) is a novel transplant procedure that can largely reduce or even prevent IRI, but the clinical relevance of IFLT and the recurrence of HCC after liver transplantation are still unknown. This retrospective study compared survival outcomes, HCC recurrence, perioperative data and IRI severity following liver transplantation (LT). 30 patients received IFLT and 196 patients received conventional liver transplantation (CLT) were chosen for the entire cohort between June 2017 and August 2020. A 1:3 propensity score matching was performed, 30 IFLT recipients and 85 matched CLT patients were enrolled in propensity-matched cohorts. An univariate and multivariate Cox regression analysis was performed, and showed surgical procedure (CLT vs IFLT) was an independent prognostic factor (HR 3.728, 95% CI 1.172-11.861, P=0.026) for recurrence free survival (RFS) in HCC patients following liver transplantation. In the Kaplan–Meier analysis, the RFS rates at 1 and 3 years after LT in recipients with HCC in the IFLT group were significantly higher than those in the CLT group both in the entire cohort and propensity-matched cohort (P=0.006 and P=0.048, respectively). In addition, patients in the IFLT group had a lower serum lactate level, lower serum ALT level and serum AST level on postoperative Day 1. LT recipients with HCC in the IFLT group had a lower incidence of early allograft dysfunction than LT recipients with HCC in the CLT group. Histological analysis showed no obvious hepatocyte necrosis or apoptosis in IFLT group. In conclusion, IFLT can significantly reduce IRI damage and has the potential to be a useful strategy to reduce HCC recurrence after liver transplantation.

New Insights in Mechanisms and Therapeutics for Short- and Long-Term Impacts of Hepatic Ischemia Reperfusion Injury Post Liver Transplantation

Liver transplantation has been identified as the most effective treatment for patients with end-stage liver diseases. However, hepatic ischemia reperfusion injury (IRI) is associated with poor graft function and poses a risk of adverse clinical outcomes post transplantation. Cell death, including apoptosis, necrosis, ferroptosis and pyroptosis, is induced during the acute phase of liver IRI. The release of danger-associated molecular patterns (DAPMs) and mitochondrial dysfunction resulting from the disturbance of metabolic homeostasis initiates graft inflammation. The inflammation in the short term exacerbates hepatic damage, leading to graft dysfunction and a higher incidence of acute rejection. The subsequent changes in the graft immune environment due to hepatic IRI may result in chronic rejection, cancer recurrence and fibrogenesis in the long term. In this review, we mainly focus on new mechanisms of inflammation initiated by immune activation related to metabolic alteration in the short term during liver IRI. The latest mechanisms of cancer recurrence and fibrogenesis due to the long-term impact of inflammation in hepatic IRI is also discussed. Furthermore, the development of therapeutic strategies, including ischemia preconditioning, pharmacological inhibitors and machine perfusion, for both attenuating acute inflammatory injury and preventing late-phase disease recurrence, will be summarized in the context of clinical, translational and basic research.

The beneficial impacts of splanchnic vasoactive agents on hepatic functional recovery in massive hepatectomy porcine model

Background

Excessive portal pressure after massive hepatectomy can cause hepatic sinusoidal injury and have deleterious impacts on hepatic functional recovery, contributing to developing post-hepatectomy liver failure. This study aimed to assess the effects of splanchnic vasoactive agents on hepatic functional recovery and regeneration while clarifying the underlying mechanism, using a 70% hepatectomy porcine model.

Methods

Eighteen pigs undergoing 70% hepatectomy were involved in this study and divided into three groups: control (n=6), terlipressin (n=6), and octreotide (n=6). Terlipressin (0.5 mg) and octreotide (0.2 mg) were administered 3 times a day for each group with the first dose starting just before surgery until the 7th postoperative day, at which time the surviving pigs were sacrificed. During the period, portal pressure, liver weight, biochemical analysis, histological injury score, and molecular markers were evaluated and compared between groups.

Results

The 7-day survival rates in the octreotide, terlipressin, and control groups were 100%, 83.3%, and 66.7%, respectively. The portal pressures decreased in both terlipressin and octreotide groups than the control group at 30 minutes, 1 hour and 6 hours after hepatectomy. The amount of regeneration measured by liver weight to body weight ratio at the time of sacrifice in the terlipressin group was smaller than that in the control group (117% vs. 129%, P=0.03). Serum aspartate aminotransferase (AST) and total bilirubin levels at 1 and 6 hours after hepatectomy and prothrombin time/international normalized ratio (PT/INR) at 6 hours after hepatectomy were significantly improved in the terlipressin and octreotide groups compared to the control group. Serum endothelin-1 (ET-1) was significantly lower in the terlipressin group than that in the control group 6 hours after hepatectomy (P<0.01). The histological injury score in the control group was significantly higher than that in the terlipressin group on the 7th postoperative day (P<0.01).

Conclusions

Splanchnic vasoactive agents, such as terlipressin and octreotide, could effectively decrease portal pressure and attenuate liver injury after massive hepatectomy.

Monocytic MDSC mobilization promotes tumor recurrence after liver transplantation via CXCL10/TLR4/MMP14 signaling

Tumor recurrence is the major obstacle for pushing the envelope of liver transplantation for hepatocellular carcinoma (HCC) patients. The inflammatory cascades activated by acute liver graft injury promote tumor recurrence. We aimed to explore the role and mechanism of myeloid-derived suppressor cell (MDSC) mobilization induced by liver graft injury on tumor recurrence. By analyzing 331 HCC patients who received liver transplantation, the patients with graft weight ratio (GWR, the weight of liver graft divided by the estimated standard liver weight of recipient) <60% had higher tumor recurrence than GWR ≥60% ones. MDSCs and CXCL10/TLR4 levels were significantly increased in patients with GWR <60% or tumor recurrence. These findings were further validated in our rat orthotopic liver transplantation model. In CXCL10^−/− and TLR4^−/− mice of hepatic ischemia/reperfusion injury plus major hepatectomy (IRH) model, monocytic MDSCs, instead of granulocytic MDSCs, were significantly decreased. Importantly, CXCL10 deficiency reduced the accumulation of TLR4⁺ monocytic MDSCs, and CXCL10 increased MDSC mobilization in the presence of TLR4. Moreover, MMP14 was identified as the key molecule bridging CXCL10/TLR4 signaling and MDSC mobilization. Knockout or inhibition of CXCL10/TLR4 signaling significantly reduced the tumor growth with decreased monocytic MDSCs and MMP14 in the mouse tumor recurrent model. Our data indicated that monocytic MDSCs were mobilized and recruited to liver graft during acute phase injury, and to promote HCC recurrence after transplantation. Targeting MDSC mobilization via CXCL10/TLR4/MMP14 signaling may represent the therapeutic potential in decreasing post-transplant liver tumor recurrence.

Intrahepatic recurrence of hepatocellular carcinoma after resection: an update

Hepatocellular carcinoma recurrence occurs in 40-70% of patients after hepatic resection. Despite the high frequency of hepatocellular cancer relapse, there is no established guidance for the management of such cases. The evaluation of prognostic factors that indicate a high risk of recurrence after surgery such as the tumor number and size and the presence of microvascular invasion may guide the therapeutic strategy and point out which patients should be strictly monitored. Additionally, the administration of adjuvant treatment or ab initio liver transplantation in selected patients with high-risk characteristics could have a significant impact on the prevention of relapse and overall survival. Once the recurrence has occurred in the liver remnant, the available therapeutic options include re-resection, salvage liver transplantation and locoregional treatments, although the therapeutic choice is often challenging and should be based on the characteristics of the recurrent tumor, the patient profile and most importantly the timing of relapse. Aggressive combination treatments are often required in challenging cases of early relapse. The results of the above treatment strategies are reviewed and compared to determine the optimal management of patients with recurrent hepatocellular cancer following liver resection.

Clinical Significance of Spontaneous Portosystemic Shunts in Living Donor Liver Transplantation

Spontaneous portosystemic shunts (SPSS) are commonly observed in patients undergoing living donor liver transplantation (LDLT); however, their impact on the outcome after transplantation is unclear. We aimed to assess the type, size, and the effects of SPSS on outcomes after LDLT. A total of 339 LDLT recipients in a single institution were included. The type and diameter of the SPSS (splenorenal shunt [SRS], oesogastric shunt, and umbilical shunt) were retrospectively analyzed. A large shunt was defined as having a diameter ≤7 mm. No portal flow modulation was attempted over time. Portal complications were defined as stenosis, thrombosis, or hepatofugal flow requiring any treatment after transplantation. There were 202 (59.0%) patients who exhibited at least 1 large SPSS. Neither the size nor type of SPSS was associated with mortality, morbidity, or liver function recovery. However, the incidence of portal complications was significantly higher in patients with a large SRS (8.6% versus 2.9%; P = 0.04). Multivariate analysis of portal complications revealed 2 independent predictors: pre-LT portal vein thrombosis (PVT) and SRS size. The observed risk among recipients with pre-LT PVT was 8.3% when the SRS was ≤7 mm, but increased to 38.5% when the SRS was >15 mm. The present study suggests that large SPSS do not negatively affect the outcomes after LDLT. However, a large SRS is associated with a higher risk of portal complications, particularly in recipients with pre-LT PVT, for whom intraoperative intervention for SRS should be considered. Otherwise, a conservative approach to SPSS during LDLT seems reasonable.

Increased Surgical Complications but Improved Overall Survival with Adult Living Donor Compared to Deceased Donor Liver Transplantation: A Systematic Review and Meta-Analysis

Background

Living donor liver transplantation (LDLT) provides an alternative to deceased donor liver transplantation (DDLT) for patients with end-stage liver disease in the circumstance of scarcity of deceased grafts. However, the outcomes of LDLT remain controversial.

Method

A systematic review and meta-analysis were performed to compare the outcomes of LDLT with DDLT. Twelve outcomes were assessed.

Results

Thirty-nine studies involving 38563 patients were included. LDLT was comparable in red blood cell transfusion, perioperative mortality, length of hospital stay, retransplantation rate, hepatitis C virus recurrence rate, and hepatocellular carcinoma recurrence rate with DDLT. Cold ischemia time was shorter and duration of recipient operation was longer in LDLT. Postoperative intra-abdominal bleeding rate occurred less frequently in LDLT recipients (odds ratio (OR) = 0.64, 95%confidence interval (CI) = 0.46 − 0.88, P = 0.006), but this did not decrease the perioperative mortality. LDLT was associated with significantly higher biliary (OR = 2.23, 95%CI = 1.59 − 3.13, P < 0.00001) and vascular (OR = 2.00, 95%CI = 1.31 − 3.07, P = 0.001) complication rates and better overall survival (OS) (1 year: OR = 1.32, 95%CI = 1.01 − 1.72, P = 0.04; 3 years: OR = 1.39, 95%CI = 1.14 − 1.69, P = 0.0010; and 5 years: OR = 1.33, 95%CI = 1.04 − 1.70, P = 0.02). According to subgroup analysis, biliary complication rate and OS improved dramatically as experience increased, while vascular complication rate could not be improved because it was mainly caused by the difference of the donor type itself.

Conclusions

LDLT remains a valuable option for patients in need of liver transplantation for it provides an excellent alternative to DDLT without compromising recipient outcomes. Further refinement in biliary and vascular reconstruction techniques and the accumulation of liver transplantation centers' experience are the key factors in expanding the application of LDLT.

Small-for-size syndrome in liver transplantation: Definition, pathophysiology and management

BACKGROUND

Since the first success in an adult patient, living donor liver transplantation (LDLT) has become an universally used procedure. Small-for-size syndrome (SFSS) is a well-known complication after partial LT, especially in cases of adult-to-adult LDLT. The definition of SFSS slightly varies among transplant physicians. The use of a partial liver graft has risks of SFSS development. Persistent portal vein (PV) hypertension and PV hyper-perfusion after LT were identified as the main factors. Hence, various approaches were explored to modulate PV flow and decrease PV pressure in order to alleviate this syndrome. Herein, the definition, clinical symptoms, pathophysiology, basic research, as well as preventive and treatment strategies for SFSS are reviewed based on an extensive review of the literature and on our own experiences.

DATA SOURCES

The articles were collected through PubMed using search terms "liver transplantation", "living donor liver transplantation", "living liver donation", "partial graft", "small-for-size graft", "small-for-size syndrome", "graft volume", "remnant liver", "standard liver volume", "graft to recipient body weight ratio", "sarcopenia", "porcine", "swine", and "rat". English publications published before March 31, 2020 were included in this review.

RESULTS

Many transplant surgeons performed PV flow modulation, including portocaval shunt, splenic artery ligation and splenectomy. With these techniques, patient outcome has been improved even when using a "small" graft. Other factors, such as preoperative recipients' nutritional and skeletal muscle status, graft congestion, and donor factors, were also identified as risk factors which all have been addressed using various strategies.

CONCLUSIONS

The surgical approach controlling PV flow and pressure could help to prevent SFSS especially in severely ill recipients. In the absence of efficacious medications to resolve SFSS, conservative treatments, including aggressive fluid balance correction for massive ascites, anti-microbiological therapy to prevent or control sepsis and intensive nutritional therapy, are all required if SFSS could not be prevented.

Evaluation of the role of transhepatic flow in postoperative outcomes following major hepatectomy (THEFLOW): study protocol for a single-centre, non-interventional cohort study

INTRODUCTION

Liver resection is the only curative treatment for primary and secondary hepatic tumours. Improvements in perioperative preparation of patients and new surgical developments have made complex liver resections possible. However, small for size and flow syndrome (SFSF) is still a challenging issue, rendering patients inoperable and causing postoperative morbidity and mortality. Although the role of transhepatic flow in the postoperative outcome has been shown in small partial liver transplantation and experimental studies of SFSF, this has never been studied in the clinical setting following liver resection. The aim of this study is to systematically evaluate transhepatic flow changes following major liver resection and its correlation with postoperative outcomes.

METHODS AND ANALYSIS

The TransHEpatic FLOW (THEFLOW) study is a single-centre, non-interventional cohort study, and aims to enrol 50 patients undergoing major hepatectomy (defined as hemihepatectomy or extended hepatectomy based on the Brisbane classification) with or without prior chemotherapy. The portal venous flow, hepatic artery flow and portal venous pressure are measured before and after each resection. All patients are followed-up for 3 months after the operation. During each evaluation, standard clinical data, posthepatectomy liver failure and overall morbidity and mortality will be recorded. THEFLOW study was initiated on 25 March 2018 and is expected to progress for 2 years.

ETHICS AND DISSEMINATION

This protocol study received approval from the Ethics Committee of the University of Heidelberg (registration number: S576/2017). The results of this study will be published in a peer-reviewed journal, and will also be presented at medical meetings.

TRIAL REGISTRATION NUMBER

NCT03762876.

Adult-to-adult living-donor liver transplantation: The experience of the Université catholique de Louvain

BACKGROUND

Liver transplantation is the treatment for end-stage liver diseases and well-selected malignancies. The allograft shortage may be alleviated with living donation. The initial UCLouvain experience of adult living-donor liver transplantation (LDLT) is presented.

METHODS

A retrospective analysis of 64 adult-to-adult LDLTs performed at our institution between 1998 and 2016 was conducted. The median age of 29 (45.3%) females and 35 (54.7%) males was 50.2 years (interquartile range, IQR 32.9-57.5). Twenty-two (34.4%) recipients had no portal hypertension. Three (4.7%) patients had a benign and 33 (51.6%) a malignant tumor [19 (29.7%) hepatocellular cancer, 11 (17.2%) secondary cancer and one (1.6%) each hemangioendothelioma, hepatoblastoma and embryonal liver sarcoma]. Median donor and recipient follow-ups were 93 months (IQR 41-159) and 39 months (22-91), respectively.

RESULTS

Right and left hemi-livers were implanted in 39 (60.9%) and 25 (39.1%) cases, respectively. Median weights of right- and left-liver were 810 g (IQR 730-940) and 454 g (IQR 394-534), respectively. Graft-to-recipient weight ratios (GRWRs) were 1.17% (right, IQR 0.98%-1.4%) and 0.77% (left, 0.59%-0.95%). One- and five-year patient survivals were 85% and 71% (right) vs. 84% and 58% (left), respectively. One- and five-year graft survivals were 74% and 61% (right) vs. 76% and 53% (left), respectively. The patient and graft survival of right and left grafts and of very small (<0.6%), small (0.6%-0.79%) and large (≥0.8%) GRWR were similar. Survival of very small grafts was 86% and 86% at 3- and 12-month. No donor died while five (7.8%) developed a Clavien-Dindo complication IIIa, IIIb or IV. Recipient morbidity consisted mainly of biliary and vascular complications; three (4.7%) recipients developed a small-for-size syndrome according to the Kyushu criteria.

CONCLUSIONS

Adult-to-adult LDLT is a demanding procedure that widens therapeutic possibilities of many hepatobiliary diseases. The donor procedure can be done safely with low morbidity. The recipient operation carries a major morbidity indicating an important learning curve. Shifting the risk from the donor to the recipient, by moving from the larger right-liver to the smaller left-liver grafts, should be further explored as this policy makes donor hepatectomy safer and may stimulate the development of transplant oncology.

Simulating Transplant Small-for-size Grafts Using Human Liver Monosegments: The Impact of Portal Perfusion Pressure

Small-for-size-liver grafts (SFSG) in adult transplant recipients have elevated risk of graft failure, limiting its application in clinical liver transplantation. Relevant preclinical model of SFSG is lacking. Relevant to deceased-donor split liver transplant and living-donor liver transplant in adult recipients, in this study, we present our initial characterization of SFSG model using monosegments of a discarded human donor liver.

Heme Oxygenase 1 Attenuates Hypoxia-Reoxygenation Injury in Mice Liver Sinusoidal Endothelial Cells

BACKGROUND

Heme oxygenase 1 (HO-1), a heat shock protein, can be involved in the resolution of inflammation by modulating cytokine expression and apoptotic cell death. Based on recent evidence that liver sinusoidal endothelial cells (LSECs) is the critical target in early period of liver ischemia-reperfusion injury (IRI), this study aims to clarify whether overexpression of HO-1 gene provides a protective effect on mice LSECs.

METHODS

LSECs were transfected with adenovirus vectors encoding mice HO-1 gene (Ad-HO-1) or green fluorescent protein. Controls were not infected with any vector. LSECs were then treated with hypoxic or normoxic culture. We used low serum culture medium and hypoxia-reoxygenation (H-R) conditions to cause IRI in vitro. The transfection efficiency of HO-1 gene in LSECs, after 48 hours of transfection, and the effect of HO-1 on the model of H-R injury in LSECs were observed.

RESULTS

Transfection of LSECs with Ad-HO-1 was at an optimal dose (multiplicity of infection = 80) to markedly express HO-1 mRNA and protein. Groups of overexpressed HO-1 showed lower levels of inflammatory factor mediators IL-6 and TNF-α. Survival rate of the cells after H-R injury was higher and attributed to overexpressed HO-1. In contrast, the control adenovirus expressing the enhanced green fluorescent protein failed to induce HO-1 expression and stimulated cell apoptosis. HO-1 expression was downregulated in all H-R groups compared with normoxia groups, which may be related to the disruption of the LSEC structure.

CONCLUSIONS

Upregulation of HO-1 can attenuate H-R injury in LSECs by inhibiting proinflammatory cytokine release and diminishing apoptotic cell death.

Efficacy of Sorafenib for the Treatment of Post-Transplant Hepatocellular Carcinoma Recurrence

BACKGROUND

The role of sorafenib in patients with hepatocellular carcinoma (HCC) recurrence after liver transplantation (LT) has been rarely studied. The aim of this study was to evaluate the efficacy of sorafenib in post-LT era.

METHODS

Consecutive patients with post-transplant HCC recurrence not eligible to resection or locoregional therapy were included. Patients receiving best supportive care (BSC) until 2007 were compared with those treated by sorafenib thereafter.

RESULTS

Of a total of 65 patients, 20 patients received BSC and 45 received sorafenib. Clinical characteristics were similar between two groups except that sorafenib group received tacrolimus and mammalian target-of-rapamycin inhibitors more frequently than BSC group. Treatment with sorafenib conferred a survival advantage as compared with BSC for survival after recurrence (median, 14.2 vs. 6.8 months; P = 0.01). In multivariate analyses, high serum α-fetoprotein level, synchronous intrahepatic recurrence and distant metastasis at the time of recurrence, and BSC were independently associated with poorer survival after recurrence. Sorafenib treatment was associated with better survival after recurrence as compared with BSC (hazard ratio, 0.25; 95% confidence interval, 0.10-0.62; P = 0.002). In addition, sorafenib group showed tolerable toxicity in the post-transplant setting.

CONCLUSION

Sorafenib may be beneficial in patients with post-transplant HCC recurrence.

Liver Transplantation for Hepatitis B Virus-related Hepatocellular Carcinoma in Hong Kong

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related deaths worldwide. Curative resection is frequently limited in Hong Kong by hepatitis B virus-related cirrhosis, and liver transplantation is the treatment of choice. Liver transplantation has been shown to produce superior oncological benefits, when compared to hepatectomy for HCC. New developments in the context of patient selection criteria, modification of organ allocation, bridging therapy, salvage liver transplantation and pharmaceutical breakthrough have improved the survival of HCC patients. In this article, we will share our experience in transplanting hepatitis B virus-related HCC patients in Hong Kong and discuss the recent progress in several areas of liver transplantation.

Comparison of Regeneration of Remnant Liver After Hemihepatectomy with or Without the Middle Hepatic Vein

BACKGROUND

There is no consensus about remnant liver regeneration associated with middle hepatic vein (MHV) resecting.

METHODS

Seventy-five patients who underwent hemihepatectomy were retrospectively analysed with respect to remnant liver regeneration. The liver remnant volume (LRV) and each sectional volume were postoperatively measured with multidetector computed tomography at day 7 and months 1, 2, 5, and 12 after the operation.

RESULTS

In right hemihepatectomy cases, the regeneration rate of LRV in the MHV preservation group was significantly higher than that of the MHV resection group at months 5 and 12. In particular, the regeneration rate of remnant segment IV peaked at day 7 and was shrunk after 1 month, and was significant higher in the MHV preservation group. In left hemihepatectomy cases, the regeneration rate of LRV at month 12 was significantly higher in the MHV preservation group. The regeneration rate of the remnant anterior section peaked at 1 month and was shrunk.

CONCLUSION

In this study, the MHV should be preserved or reconstructed whenever possible during hepatic hemihepatectomy. Hepatic regeneration in the MHV perfusion region becomes poor within 7 days to 1 month after surgery (UMIN000023714).

Predicting post-hepatectomy liver failure by combined volumetric, functional MR image and laboratory analysis

BACKGROUND & AIMS

To assess the efficacy of functional MR image with volumetric, liver function test and indocyanine green clearance (ICG) in identifying the patients who are at risk of post-hepatectomy liver failure (PHLF).

METHODS

We retrospectively included 115 patients undergoing gadoxetic acid-enhanced MR imaging before hepatectomy at one medical centre from January 2013 to December 2015. Contrast enhancement ratio (CER) between transitional and hepatobiliary phases (3 and 30 minutes post-contrast) was calculated. Total liver volume (TLV) and spleen volume (Sp) were measured. Post-operatively, the histological Ishak fibrosis score was collected. Potential risk factors for liver failure were analysed, and the performance was examined by receiver operating characteristic curve.

RESULTS

Post-hepatectomy liver failure (PHLF) occurred in 16 patients (13.9%). TLV/SLV, ADC value, CER_HBP/TP and total liver contrast enhancement ratio (tCER) were associated with PHLF (P < .05). Between PHLF and non-PHLF groups, remnant liver volume (RLV), RLV/SLV, Sp/RLV, remnant liver contrast enhancement ratio (rCER) and Ishak fibrosis score showed statistical difference. rCER showed superiority in diagnostic performance (AUC = 0.78) with the optimal cut-off value of 1.23.

CONCLUSIONS

Gadoxetic acid-enhanced MR imaging with volumetric is a reliable method for evaluating functional liver volume and determining the risk of PHLF.

Portal venous pressure and proper graft function in living donor liver transplants in 69 patients from an Egyptian center

BACKGROUND

Several studies have defined the optimal portal pressure suitable for adequate graft renewal in liver transplantation (LT) but none have studied an Egyptian population to our knowledge.

OBJECTIVES

Determine the level of portal venous pressure (PVP) for adequate graft function, and study the effect of PVP modulation on the outcome of LT in an Egyptian population.

DESIGN

Cross-sectional, prospectively collected data.

SETTING

Liver transplantation unit.

PATIENTS AND METHODS

The study included adult cirrhotic pa.tients who underwent right lobe liver donor living transplantation (LDLT) at our transplantation center. Intraoperative Doppler was performed on all LDLT patients. Two PVP measurements were obtained during the recipient operation: before PV clamping and after graft re-perfusion. These PVP measurements were correlated with the results of intraoperative and postoperative Doppler findings and graft function. Mortality in the early postoperative period ( less than 1 month) and development of small-for-size syndrome (SFSS) were recorded.

MAIN OUTCOME MEASURES

PVP, graft injury, and the effect of PVP modulation on the outcome of LT were the primary outcome measures. Secondary outcome measures were to correlate PVP to portal vein hemodynamics and intraoperative mean hepatic artery, peak systolic velocity, and also to correlate PVP with the postoperative graft function and mean postoperative platelet count.

SAMPLE SIZE AND CHARACTERISTICS

69 adult patients with end-stage liver disease.

RESULTS

Post-reperfusion PVP was lower than pre-clamping PVP. The mean pre-clamping and post-reperfusion values were higher in patients who experienced early mortality and in patients with smaller grafts. A PVP greater than 16.5 mm Hg at the end of the operation predicted the development of SFSS (sensitivity=91.7% and specificity=50.5%). Cases of high PVP that were modulated to a lower level had a smooth and uneventful postoperative outcome.

CONCLUSION

PVP is a significant hemodynamic factor that influences the functional status of the transplanted liver, including the development of SFSS, in the Egyptian population. PVP modulation may improve the outcome of LDLT.

LIMITATIONS

Further study with a larger sample is needed to confirm these results.

CONFLICT OF INTEREST

None.

Glutathione Peroxidase 3 Delivered by hiPSC-MSCs Ameliorated Hepatic IR Injury via Inhibition of Hepatic Senescence

Background and Aims: Down-regulation of GPx3 accelerated hepatic senescence, which further caused overwhelming inflammation and severe liver graft injury. MSCs derived from human induced pluripotent stem cells (hiPSC-MSCs) have been developed as more efficient delivery vehicle with the property of injury tropism. Here, we aimed to explore the suppressive role of GPx3 in hepatic IR injury using novel delivery system of hiPSC-MSCs.

Methods: The mice IR injury model with partial hepatectomy was established. The engineered hiPSC-MSCs delivering GPx3 was constructed. All the mice were segregated into three groups. hiPSC-MSC-GPx3, hiPSC-MSC-pCDH (vector control) or PBS were injected via portal vein after reperfusion. Liver injury was evaluated by histological and serological test. Hepatic apoptosis was detected by Tunel staining and remnant liver regeneration was assessed by Ki67 staining. The role of hepatic senescence in liver graft injury was evaluated in rat orthotopic liver transplantation model. The suppressive effect of GPx3 on hepatic senescence was examined in mice IR injury model and confirmed in vitro. Hepatic senescence was detected by SA-β-Gal and P^16/ink4a staining.

Results: GPx3 can be successfully delivered by hiPSC-MSCs into liver tissues. Histological examination showed that hiPSC-MSC-GPx3 treatment significantly ameliorated hepatic IR injury post-operation. Significantly lower LDH (891.43±98.45 mU/mL, P<0.05) and AST (305.77±36.22 IU/L, P<0.01) were observed in hiPSC-MSC-GPx3 group compared with control groups. Less apoptotic hepatocytes were observed and the remnant liver regeneration was more active in hiPSC-MSC-GPx3 group. In rat orthotopic liver transplantation model, more senescent hepatocytes were observed in small-for-size liver graft, in which GPx3 expression was significantly compromised. In mice IR injury model, hiPSC-MSC-GPx3 significantly suppressed hepatic senescence. In addition, rGPx3 inhibited cellular senescence of liver cells in a dose dependent manner. Four candidate genes (CD44, Nox4, IFNG, SERPERINB2) were identified to be responsible for suppressive effect of GPx3 on hepatic senescence.

Conclusion: Engineered hiPSC-MSCs delivering GPx3 ameliorated hepatic IR injury via inhibition of hepatic senescence.

Small-for-size grafts increase recurrence of hepatocellular carcinoma in liver transplantation beyond milan criteria

Living donor liver transplantation (LDLT) has been reported to have high rates of hepatocellular carcinoma (HCC) recurrence compared with deceased donor liver transplantation (DDLT). This has been assumed to be due to the frequent use of small-for-size grafts (SFSGs) in LDLT rather than DDLT, but the relationship between graft size and prognosis remains controversial. This study aimed to clarify the effect of SFSGs on the oncologic outcomes of patients with HCC who underwent LDLT. Between January 2005 and December 2015, 597 consecutive patients underwent LDLT. Among these patients, those with HCC who underwent LDLT were randomly matched at a 1:3 ratio (graft-to-recipient body weight ratio [GRWR] < 0.8%:GRWR > 0.8%) according to propensity score. HCC recurrence and patient survival were analyzed using the Kaplan-Meier method and log-rank test. In addition, stratified subgroup analysis based on the Milan criteria was performed. SFSG was defined as a GRWR < 0.8%. Using propensity score matching, 82 patients with GRWR < 0.8% and 246 patients with GRWR ≥ 0.8% were selected. For patients with HCC within the Milan criteria, no significant difference of HCC recurrence (P = 0.82) and patient survival (P = 0.95) was found based on GRWR. However, for patients with HCC beyond the Milan criteria, 1-, 3-, and 5-year recurrence-free survival rates were 52.4%, 49.3%, and 49.3%, respectively, for patients with GRWR < 0.8%, and 76.5%, 68.3%, and 64.3%, respectively, for patients with GRWR ≥ 0.8% (P = 0.049). The former group exhibited poor patient survival rates (P = 0.047). In conclusion, for patients with HCC within the Milan criteria, no significant difference in oncologic outcomes was found based on liver graft size. However, among the patients with HCC beyond the Milan criteria, SFSG recipients showed poor oncologic outcomes. Because extended criteria are frequently used in LDLT for HCC, a recipient's prognosis can be improved if a liver graft of appropriate size is carefully selected during donor selection. Liver Transplantation 24 35-43 2018 AASLD.

The Impact of Liver Graft Injury on Cancer Recurrence Posttransplantation

Liver transplantation is the most effective treatment for selected patients with hepatocellular carcinoma. However, cancer recurrence, posttransplantation, remains to be the critical issue that affects the long-term outcome of hepatocellular carcinoma recipients. In addition to tumor biology itself, increasing evidence demonstrates that acute-phase liver graft injury is a result of hepatic ischemia reperfusion injury (which is an inevitable consequence during liver transplantation) and may promote cancer recurrence at late phase posttransplantation. The liver grafts from living donors, donors after cardiac death, and steatotic donors have been considered as promising sources of organs for liver transplantation and are associated with high incidence of liver graft injury. The acute-phase liver graft injury will trigger a series of inflammatory cascades, which may not only activate the cell signaling pathways regulating the tumor cell invasion and migration but also mobilize the circulating progenitor and immune cells to facilitate tumor recurrence and metastasis. The injured liver graft may also provide the favorable microenvironment for tumor cell growth, migration, and invasion through the disturbance of microcirculatory barrier function, induction of hypoxia and angiogenesis. This review aims to summarize the latest findings about the role and mechanisms of liver graft injury resulted from hepatic ischemia reperfusion injury on tumor recurrence posttransplantation, both in clinical and animal cohorts.

Comparative study of the effects of terlipressin versus splenectomy on liver regeneration after partial hepatectomy in rats

BACKGROUND

Post-hepatectomy liver failure as a result of insufficient liver remnant is a feared complication in liver surgery. Efforts have been made to find new strategies to support liver regeneration. The aim of this study was to investigate the effects of terlipressin versus splenectomy on postoperative liver function and liver regeneration in rats undergoing 70% partial hepatectomy.

METHODS

Seventy-two male Wistar rats were randomly assigned into three groups (n=24 in each group): 70% partial hepatectomy as control (PHC), 70% partial hepatectomy with splenectomy (PHS) or 70% partial hepatectomy with a micropump for terlipressin administration (PHT). Eight rats in each group were sacrificed on postoperative day (POD) 1, 3 and 7. To assess liver regeneration, immunohistochemical analysis of liver tissue using bromodeoxyuridine (BrdU) and Ki-67 labeling was performed. Portal venous pressure, serum concentrations of creatinine, urea, albumin, bilirubin and prothrombin time as well as liver-, body-weight and their ratio were determined on POD 1, 3 and 7.

RESULTS

The liver-, body-weight and their ratio were not statistically different among the groups. On POD 1, 3 and 7 portal venous pressure in the intervention groups (PHT: 8.13±1.55, 10.38±1.30, 6.25±0.89 cmH₂O and PHS: 7.50±0.93, 8.88±2.42, 5.75±1.04 cmH₂O) was lower compared to the control group (PHC: 8.63±2.06, 10.50±2.45, 6.50±2.67 cmH₂O). Hepatocyte proliferation in the intervention groups was delayed, especially after splenectomy on POD 1 (BrdU: PHS vs PHC, 20.85%±13.05% vs 28.11%±10.10%; Ki-67, 20.14%±14.10% vs 23.96%±11.69%). However, none of the differences were statistically significant.

CONCLUSIONS

Neither the administration of terlipressin nor splenectomy improved liver regeneration after 70% partial hepatectomy in rats. Further studies assessing the regulation of portal venous pressure as well as extended hepatectomy animal models and liver function tests will help to further investigate mechanisms of liver regeneration.

Living donor liver transplantation for hepatocellular cancer: an (almost) exclusive Eastern procedure?

Hepatocellular carcinoma (HCC) is the fifth most prevalent cancer and it is linked with chronic liver disease. Liver transplantation (LT) is the best curative treatment modality, since it can cure simultaneously the underlying liver disease and HCC. Milan criteria (MC) are the benchmark for selecting patients with HCC for LT, achieving up to 91% 1-year survival post transplantation. However, when considering intention-to-treat (ITT) rates are substantially lower, mainly due dropout. Additionally, Milan criteria (MC) are too restrictive and more inclusive criteria have been reported with good outcomes. Mainly, in Eastern countries, deceased donors are scarce, therefore Asian centers have developed living-donor liver transplantation (LDLT) to a state-of-art status. There are many eastern centers reporting huge numbers of LDLT with outstanding results. Regarding HCC patients, they have reported many criteria including more advanced tumors achieving reasonable outcomes. Western countries have well-established deceased-donor liver transplantation (DDLT) programs. However, organ shortage and restrictive criteria for listing patients with HCC endorses LDLT as a good option to offer curative treatment to more HCC patients. However, there are some controversial reports claiming higher rates of HCC recurrence after LDLT than DDLT. An extensive review included 30 studies with cohorts of HCC patients who underwent LDLT in both East and West countries. We reported also the results of our Institution, in Brazil, where it was performed the first LDLT. This review also addresses the eligibility criteria for transplanting patients with HCC developed in Western and Eastern countries.

Von Willebrand Factor Deposition and ADAMTS-13 Consumption in Allograft Tissue of Thrombotic Microangiopathy-like Disorder After Living Donor Liver Transplantation: A Case Report

BACKGROUND

Thrombotic microangiopathy (TMA) pathogenesis after living donor liver transplantation (LDLT) is thought to be caused by release of unusually large von Willebrand factor multimers (UL-vWFMs) resulting from sinusoidal endothelial cell damage and induction of platelet adhesion and aggregation. A decrease in a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs-13 (ADAMTS-13) that cleave UL-vWFMs might cause excessive UL-vWFMs activity and result in platelet thrombus formation. However, this phenomenon has not undergone a full pathologic assessment.

PROCEDURES

A 60-year-old man was diagnosed with hepatitis C-related end-stage cirrhosis. His son was the donor, and he underwent LDLT. On postoperative day 44, his laboratory findings met most TMA diagnostic criteria, and he was diagnosed with TMA-like disorder (TMALD). Localization of CD42b as a platelet marker, vWF, and ADAMTS-13 in allograft tissue of this patient were evaluated using immunohistochemistry.

RESULTS

CD42b expression was observed as platelet aggregates attached to hepatocytes or within the hepatocyte cytoplasm, a morphology called extravasated platelet aggregation (EPA). vWF expression was observed mainly as deposited compact clusters, and ADAMTS-13 expression resembled distinct dots throughout the liver tissue.

CONCLUSION

These findings suggest that EPA indicated sinusoidal endothelial cell damage followed by detachment, and vWF deposition resulted from UL-vWFM oversynthesis. ADAMTS-13 might be consumed in the allograft tissue to cleave UL-vWFMs, but ADAMTS-13 levels might be insufficient to cleave all the deposited UL-vWFMs. We present the case of an LDLT recipient diagnosed with TMALD using blood tests, which showed the presence of TMA pathogenesis in the allograft.

Effects of heme oxygenase-1-modified bone marrow mesenchymal stem cells on microcirculation and energy metabolism following liver transplantation

AIM

To investigate the effects of heme oxygenase-1 (HO-1)-modified bone marrow mesenchymal stem cells (BMMSCs) on the microcirculation and energy metabolism of hepatic sinusoids following reduced-size liver transplantation (RLT) in a rat model.

METHODS

BMMSCs were isolated and cultured in vitro using an adherent method, and then transduced with HO-1-bearing recombinant adenovirus to construct HO-1/BMMSCs. A rat acute rejection model following 50% RLT was established using a two-cuff technique. Recipients were divided into three groups based on the treatment received: normal saline (NS), BMMSCs and HO-1/BMMSCs. Liver function was examined at six time points. The levels of endothelin-1 (ET-1), endothelial nitric-oxide synthase (eNOS), inducible nitric-oxide synthase (iNOS), nitric oxide (NO), and hyaluronic acid (HA) were detected using an enzyme-linked immunosorbent assay. The portal vein pressure (PVP) was detected by Power Lab ML880. The expressions of ET-1, iNOS, eNOS, and von Willebrand factor (vWF) protein in the transplanted liver were detected using immunohistochemistry and Western blotting. ATPase in the transplanted liver was detected by chemical colorimetry, and the ultrastructural changes were observed under a transmission electron microscope.

RESULTS

HO-1/BMMSCs could alleviate the pathological changes and rejection activity index of the transplanted liver, and improve the liver function of rats following 50% RLT, with statistically significant differences compared with those of the NS group and BMMSCs group (P < 0.05). In term of the microcirculation of hepatic sinusoids: The PVP on POD7 decreased significantly in the HO-1/BMMSCs and BMMSCs groups compared with that of the NS group (P < 0.01); HO-1/BMMSCs could inhibit the expressions of ET-1 and iNOS, increase the expressions of eNOS and inhibit amounts of NO production, and maintain the equilibrium of ET-1/NO (P < 0.05); and HO-1/BMMSCs increased the expression of vWF in hepatic sinusoidal endothelial cells (SECs), and promoted the degradation of HA, compared with those of the NS group and BMMSCs group (P < 0.05). In term of the energy metabolism of the transplanted liver, HO-1/BMMSCs repaired the damaged mitochondria, and improved the activity of mitochondrial aspartate aminotransferase (ASTm) and ATPase, compared with the other two groups (P <0.05).

CONCLUSION

HO-1/BMMSCs can improve the microcirculation of hepatic sinusoids significantly, and recover the energy metabolism of damaged hepatocytes in rats following RLT, thus protecting the transplanted liver.

Small-for-Size Syndrome: Bridging the Gap Between Liver Transplantation and Graft Recovery

In living donor liver transplantation, optimal graft size is estimated from values like graft volume/standard liver volume and graft/recipient body weight ratio but the final functional hepatic mass is influenced by other donor and recipient factors. Grafts with insufficient functional hepatic mass can produce a life-threatening condition with rapidly progressive liver failure called small-for-size syndrome (SFSS). Diagnosis of SFSS requires careful surveillance for signs of inadequate hepatocellular function, residual portal hypertension, and systemic inflammation that suggest rapidly progressive liver failure. Early diagnosis, symptom control, and addressing the cause of SFSS may prevent the need for retransplantation. With increased attention to avoiding donor risk, intensivists will be confronted with more SFSS recipients. In this review, we aim to outline a systematic approach to the medical management of patients with SFSS by providing a concise synopsis of general supportive care—neurological, cardiovascular, and renal support, mechanical ventilation, nutritional support, infection control, and tailored immunosuppression—with an aim to avoid end-organ damage or death and a review of current interventions including liver support devices, portal flow modulating drugs, and other experimental interventions that aim to preserve existing hepatic mass and improve conditions for hepatic regeneration. We examine evidence for SFSS interventions to provide the reader with information that may assist in clinical decision making. Points of controversy in care are purposefully highlighted to identify areas where additional experimental work is still needed. A full understanding of the pathophysiology of SFSS and measures to support liver regeneration will guide effective management.

A portal pressure cut-off of 15 versus a cut-off of 20 for prevention of small-for-size syndrome in liver transplantation: A comparative study

AIM

Portal hypertension has recently been implicated in the pathogenesis of small-for-size syndrome (SFSS) in adult-to-adult living-donor liver transplantation (A-LDLT). The aim of our study is to compare the portal venous pressure (PVP) cut-off values of 15 mmHg and 20 mmHg in terms of prevention of SFSS in A-LDLT.

METHODS

Seventy-six patients underwent A-LDLT. A PVP <20 mmHg at the end of the operation was targeted using graft inflow modulation. Patients were divided into two groups: group A, final PVP <15 mmHg; and group B, final PVP 15-19 mmHg. Peak serum bilirubin and peak international normalized ratio in the first month after A-LDLT, as well as hepatic encephalopathy, SFSS, 90-day morbidity, and mortality were observed in both groups.

RESULTS

Final PVP was well controlled below 20 mmHg in all patients (group A, n = 39; group B, n = 37). Six patients suffered SFSS in group B (16.2%) compared to one patient (2.6%) in group A (P = 0.04). Nine patients died in group B (24.3%), four of whom died of SFSS, compared to three patients in group A (7.7%) (P = 0.047).

CONCLUSION

A PVP cut-off of 15 mmHg seems to be a more appropriate target level than a cut-off of 20 mmHg for prevention of postoperative SFSS in A-LDLT.

Establishing a Porcine Model of Small for Size Syndrome following Liver Resection

BACKGROUND

Small for size syndrome (SFSS) is responsible for a high proportion of mortalities and morbidities following extended liver resection.

AIM

The aim of this study was to establish a porcine model of SFSS.

METHODS

Twenty-four Landrace pigs underwent liver resection with a remnant liver volume of 50% (group A, n = 8), 25% (group B, n = 8), and 15% (group C, n = 8). After resection, the animals were followed up for 8 days and clinical, laboratory, and histopathological outcomes were evaluated.

RESULTS

The survival rate was significantly lower in group C compared with the other groups (p < 0.001). The international normalized ratio, bilirubin, aspartate transaminase, alanine transaminase, and alkaline phosphatase levels increased shortly after surgery in groups B and C, but no change was observed in group A (p < 0.05 for all analyses). The histopathological findings in group A were mainly mild mitoses, in group B severe mitoses and hepatocyte ballooning, moderate congestion, and hemorrhage, along with mild necrosis, and in group C extended tissue damage with severe necrosis, hemorrhage, and congestion.

CONCLUSIONS

Combination of clinical, laboratory, and histopathological evaluations is needed to confirm the diagnosis of SFSS. 75% liver resection in porcine model results in SFSS. 85% liver resection causes irreversible liver failure.

Graft inflow modulation in adult-to-adult living donor liver transplantation: A systematic review

INTRODUCTION

Small-for-size syndrome (SFSS) has an incidence between 0 and 43% in small-for-size graft (SFSG) adult living donor liver transplantation (LDLT). Portal hypertension following reperfusion and the hyperdynamic splanchnic state are reported as the major triggering factors of SFSS. Intra- and postoperative strategies to prevent or to reduce its onset are still under debate. We analyzed graft inflow modulation (GIM) during adult LDLT considering the indications, efficacy of the available techniques, changes in hemodynamics and outcomes.

MATERIALS AND METHODS

A systematic literature search was performed using PubMed, EMBASE, Scopus and the Cochrane Library Central. Treatment outcomes including in-hospital mortality and morbidity, re-transplantation rate, 1-, 3-, and 5-year patient overall survival and 1-, 3-, and 5-year graft survival rates, hepatic artery and portal vein flows and pressures before and after inflow modulation were analyzed.

RESULTS

From 563 articles, 12 studies dated between 2003 and 2014 fulfilled the selection criteria and were therefore included in the study. These comprised a total of 449 adult patients who underwent inflow modulation during adult-to-adult LDLT. Types of GIM described were splenic artery ligation, splenectomy, meso-caval shunt, spleno-renal shunt, portocaval shunt, and splenic artery embolization. Mortality and morbidity ranged between 0 and 33% and 17% and 70%, respectively. Re-transplantation rates ranged between 0% and 25%. GIM was associated with good survival for both graft and recipients, reaching an 84% actuarial rate at 5 years. Through the use of GIM, irrespective of the technique, a statistically significant reduction of PVF and PVP was obtained.

CONCLUSIONS

GIM is a safe and efficient technique to avoid or limit portal hyperperfusion, especially in cases of SFSG, decreasing overall morbidity and improving outcomes.

CXCL10/CXCR3 signaling mobilized-regulatory T cells promote liver tumor recurrence after transplantation

BACKGROUND & AIMS

Liver graft injury and tumor recurrence are the major challenges of liver transplantation for the patients with hepatocellular carcinoma (HCC). Here, we aimed to explore the role and mechanism of liver graft injury mobilizing regulatory T cells (Tregs), which lead to late phase tumor recurrence after liver transplantation.

METHODS

The correlation among tumor recurrence, liver graft injury and Tregs mobilization were studied in 257 liver transplant recipients with HCC and orthotopic rat liver transplantation models. The direct roles of CXCL10/CXCR3 signaling on Tregs mobilization and tumor recurrence were investigated in CXCL10^-/- and CXCR3^-/- mice models with hepatic IR injury.

RESULTS

Clinically, patients received the graft with graft weight ratio (GWR) <60% had higher HCC recurrence after liver transplantation than the recipients with GWR ⩾60% graft. More circulating Tregs and higher intragraft TLR4/CXCL10/CXCR3 levels were detected in recipients with GWR <60% graft. These results were further validated in rat transplantation model. Foxp3⁺ cells and expressions of TLR4, CXCL10, TGFβ, CTLA-4 and CD274 were increased in rat liver tumor tissues from small-for-size graft group. In mouse model, the mobilization and recruitment of Tregs were decreased in TLR4^-/-, CXCL10^-/- and CXCR3^-/- mice compared to wild-type mice. Moreover, less CXCR3⁺ Tregs were recruited into liver in CXCL10^-/- mice after hepatic IR injury. The knockout of CXCL10 and depletion of Tregs inhibited tumor recurrence after hepatic IR injury.

CONCLUSION

CXCL10/CXCR3 signaling upregulated at liver graft injury directly induced the mobilization and intragraft recruitment of Tregs, which further promoted HCC recurrence after transplantation.

LAY SUMMARY

There were positive correlation among tumor recurrence, circulating Tregs and liver graft injury after human transplantation for HCC patients. The knockout of CXCL10 decreased hepatic recruitment of CXCR3⁺ Tregs and late phase tumor recurrence after hepatic IR injury.

Dysfunction in Patients With Small-for-Size Grafts After Living Donor Liver Transplantation

The relationship between postoperative percentage fall of platelet (PLT) counts and graft dysfunction after living donor liver transplantation (LDLT) in recipients with small-for-size (SFS) graft has not been fully evaluated. We retrospectively studied 50 adult-to-adult LDLT recipients with a graft-to-recipient weight ratio of <0.8% between 1999 and 2011. Graft dysfunction was defined as the presence of hyperbilirubinemia, coagulopathy, or ascites on 3 consecutive days during the first postoperative week. Each clinical sign of dysfunction was assigned 1 point. Postoperative percentage fall in PLT counts, graft dysfunction score, and postoperative complications according to the Clavien-Dindo classification were investigated. Overall, 31 patients (62%) exhibited a PLT count fall of more than 50%, and 19 (38%) patients exhibited a PLT count fall of less than 50% at postoperative day (POD) 3. Receiver operating characteristic curve analysis indicated that at POD 3, the cutoff value of PLT count fall was 56% for a graft dysfunction score of 2 or 3 (sensitivity, 70%; specificity, 63.3%). Fourteen of 20 patients (70%) with a dysfunction score of 2 or 3 and 11 of 30 patients (37%) with a dysfunction score of 0 or 1 showed a fall in PLT count >56% at POD 3 (P = 0.021). Grade 2 to 5 complications were more observed in patients with a dysfunction score of 2 or 3 than in patients with a dysfunction score of 0 or 1 (P < 0.001). The fall of PLT count at POD 3 >56% is an ominous sign that can predict the graft dysfunction after LDLT in recipients with SFS graft.

Liver transplantation for hepatocellular carcinoma from living-donor vs. deceased donor

With the increasing prevalence of living-donor liver transplantation (LDLT), the possible increased recurrence rate of hepatocellular carcinoma (HCC) in LDLT recipients in comparison with deceased-donor liver transplantation (DDLT) recipients has become a matter of debate. The aim of this review is to encompass current opinions and clinical reports regarding differences in the outcome, especially the recurrence of HCC, between LDLT and DDLT. In reviewing literatures, some studies reported increased recurrence rates among LDLT recipients, a majority of authors, including large database studies, reported comparable recurrence-free survival and recurrence rates between LDLT and DDLT. The postulated reasons for the increased recurrence in LDLT were the effect of graft regeneration on tumor progression, fast-tracking of patients into liver transplantation, and the more aggressive tumor characteristics in LDLT, however, many Asian LDLT centers have reported the comparable outcomes with those of DDLT in Western countries, even with the expanded criteria for HCC. In the absence of a prospective study regarding the use of LDLT versus DDLT for HCC patients, there is no evidence to support the higher HCC recurrence after LDLT than DDLT, and LDLT remains a reasonable treatment option for HCC patients with cirrhosis, especially in Asian countries where the number of deceased donor is scarce.

Clinical analysis of patients with hepatocellular carcinoma recurrence after living-donor liver transplantation

AIM: To evaluated patterns and outcomes of hepatocellular carcinoma (HCC) recurrence after living donor liver transplantation (LDLT).

METHODS: From 2001 to 2014, 293 patients underwent LDLT for HCC at our transplant center. We retrospectively reviewed 54 (18.4%) patients with HCC recurrence after LDLT. We evaluated patterns and outcomes of HCC recurrence after LDLT, with particular attention to the Milan criteria at transplantation, treatments for HCC-recurrent patients, and factors related to survival after HCC recurrence. Furthermore, we evaluated the efficacy of combination treatment of sorafenib and an mTOR inhibitor.

RESULTS: The 1-, 2-, and 3-year overall survival rates after HCC recurrence were 41.1%, 20.5%, and 15.4%, respectively. The median time interval between LDLT and HCC recurrence was 6.5 mo. Although recurrence rates according to the Milan criteria at LDLT were significantly different, HCC recurrence patterns and survival rates after HCC recurrence were not significantly different between the two groups. Time to recurrence < 12 mo (P = 0.048), multiple recurrences at HCC recurrence (P = 0.038), and palliative treatment for recurrent tumors (P = 0.003) were significant independent prognostic factors for poor survival after HCC recurrence in a multivariate analysis. The combination treatment of sorafenib and sirolimus showed survival benefits in the palliative treatment group (P = 0.005).

CONCLUSION: Curative treatment for recurrent HCC after LDLT is the most important factor in survival rates after HCC recurrence and combination treatments of sorafenib and an mTOR inhibitor could have survival benefits in patients with HCC recurrence after LT in the palliative treatment group.

Constitutive androstane receptor (Car)-driven regeneration protects liver from failure following tissue loss

BACKGROUND & AIMS

Liver can recover following resection. If tissue loss is too excessive, however, liver failure will develop as is known from the small-for-size-syndrome (SFSS). The molecular processes underlying liver failure are ill-understood. Here, we explored the role and the clinical potential of Nr1i3 (constitutive androstane receptor, Car) in liver failure following hepatectomy.

METHODS

Activators of Car, various hepatectomies, Car(-/-) mice, humanized CAR mice, human tissue and ex vivo liver slice cultures were used to study Car in the SFSS. Pathways downstream of Car were investigated by in vivo siRNA knockdown.

RESULTS

Excessive tissue loss causing liver failure is associated with deficient induction of Car. Reactivation of Car by an agonist normalizes all features associated with experimental SFSS. The beneficial effects of Car activation are relayed through Foxm1, an essential promoter of the hepatocyte cell cycle. Deficiency in the CAR-FOXM1 axis likewise is evident in human SFSS. Activation of human CAR mitigates SFSS in humanized CAR mice and improves the culture of human liver slices.

CONCLUSIONS

Impaired hepatic Car-Foxm1 signaling provides a first molecular characterization of liver that fails to recover after tissue loss. Our findings place deficient regeneration as a principal cause behind the SFSS and suggest CAR agonists may bear clinical potential against liver failure.

LAY SUMMARY

The unique regenerative capacity of liver has its natural limits. Following tissue loss that is too excessive, such as through extended resection in the clinic, liver failure may develop. This is known as small-for-size-syndrome (SFSS) and represents the most frequent cause of death due to liver surgery. Here we show that deficient induction of the protein Car, a central regulator of liver function and growth, is a cause of liver failure following extended resection; reactivation of Car through pharmacological means is sufficient to prevent or rescue the SFSS.

Small for Size and Flow (SFSF) syndrome: An alternative description for posthepatectomy liver failure

Small for Size Syndrome (SFSS) syndrome is a recognizable clinical syndrome occurring in the presence of a reduced mass of liver, which is insufficient to maintain normal liver function. A definition has yet to be fully clarified, but it is a common clinical syndrome following partial liver transplantation and extended hepatectomy, which is characterized by postoperative liver dysfunction with prolonged cholestasis and coagulopathy, portal hypertension, and ascites. So far, this syndrome has been discussed with focus on the remnant size of the liver after partial liver transplantation or extended hepatectomy. However, the current viewpoints believe that the excessive flow of portal vein for the volume of the liver parenchyma leads to over-pressure, sinusoidal endothelial damages and haemorrhage. The new hypothesis declares that in both extended hepatectomy and partial liver transplantation, progression of Small for Size Syndrome is not determined only by the "size" of the liver graft or remnant, but by the hemodynamic parameters of the hepatic circulation, especially portal vein flow. Therefore, we suggest the term "Small for Size and Flow (SFSF)" for this syndrome. We believe that it is important for liver surgeons to know the pathogenesis and manifestation of this syndrome to react early enough preventing non-reversible tissue damages.

Living vs. deceased-donor liver transplantation for patients with hepatocellular carcinoma

With the scarcity of deceased donor liver grafts, living donor liver transplantation (LDLT) is gaining popularity as an alternative to deceased donor liver transplantation (DDLT) for patients with hepatocellular carcinoma (HCC). However, as the evidence of cases of LDLT accumulates, several authors have reported higher HCC recurrence rates after LDLT. The suggested reasons for the higher recurrence rates following LDLT are related to the small-for-size graft in LDLT, surgical procedures that are specific to LDLT, and the fast-track to LDLT. Fast-tracking to LDLT may not allow sufficient time for evaluation of the biological aggressiveness of tumors, which may result in high recurrence rates due to inclusion of patients with more inherently aggressive tumors. Actually, some studies that reported higher recurrence rates with LDLT included a larger number of cases of HCC with microvascular invasion or poorly differentiated HCC. In order to exclude biologically aggressive HCC preoperatively, selection criteria incorporating tumor markers, such as alpha-fetoprotein (AFP) and des-gamma-carboxyprothrombin (DCP), as well as morphological tumor number and size have been proposed. With more reliable selection criteria incorporating biological markers to eliminate biologically aggressive HCC, LDLT can be a viable treatment option for patients with HCC, providing similar recurrence rates as those achieved with DDLT.

Serum levels of endothelin-1 after liver resection as an early predictor of postoperative liver failure. A prospective study

AIM

Besides the residual liver volume, damage of the microcirculation secondary to increased portal blood flow is a main determinant of postoperative liver failure (PLF). Endothelin-1 (ET-1), produced by sinusoidal endothelial cells, plays a key role in the regulation of hepatic microcirculation. The aim of this study was to determine whether ET-1 levels has any prognostic utility in predicting PLF.

METHODS

Patients undergoing liver resection for primary or secondary liver tumors at San Raffaele Hospital, Milan, were prospectively enrolled in the study. Serial postoperative serum ET-1 levels in patients undergoing liver resections were correlated with indices of inflammatory response, liver failure and death.

RESULTS

A total of 144 patients were included. ET-1 levels in patients who underwent major or extended liver resection were significantly higher than in patients who had a minor resection on postoperative day (POD) 1 (P = 0.003), POD 2 (P = 0.0001) and POD 5 (P = 0.0001). Eight patients developed PLF and ET-1 was significantly higher compared with patients without PLF on POD 2 (P = 0.002) and POD5 (P = 0.006). Serum ET-1 concentration on POD 2 was an independent predictor of PLF in multivariate analysis.

CONCLUSION

ET-1 is as an early index of PLF and provides a rationale for therapeutic manipulation, with many potential clinical implications to prevent PLF onset and reduce its severity.

Impact of non-oncological factors on tumor recurrence after liver transplantation in hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is the most common primary neoplasm of the liver and is one of the leading causes of cancer-related death worldwide. Liver transplantation (LT) has become one of the best curative therapeutic options for patients with HCC, although tumor recurrence after LT is a major and unaddressed cause of mortality. Furthermore, the factors that are associated with recurrence are not fully understood, and most previous studies have focused on the biological properties of HCC, such as the number and size of the HCC nodules, the degree of differentiation, the presence of hepatic vascular invasion, elevated serum levels of alpha-fetoprotein, and the tumor stage outside of the Milan criteria. Thus, little attention has been given to factors that are not directly related to HCC (i.e., “non-oncological factors”), which have emerged as predictors of tumor recurrence. This review was performed to assess the effects of non-oncological factors on tumor recurrence after LT. The identification of these factors may provide new research directions and clinical strategies for the prophylaxis and surveillance of tumor recurrence after LT, which can help reduce recurrence and improve patient survival.