Serial Assessment of Growth Factors Associated with Liver Regeneration in Patients Operated with Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy

The Impact of Chemotherapy and Transforming Growth Factor-β1 in Liver Regeneration after Hepatectomy among Colorectal Cancer Patients

An ongoing debate surrounds the impact of chemotherapy on post-hepatectomy liver regeneration in patients with colorectal cancer liver metastases (CRLM), with unclear regulatory mechanisms. This study sought to delve into liver regeneration post-resection in CRLM patients, specifically examining the roles of hepatocyte growth factor (HGF) and transforming growth factor β1 (TGF-β1). In this longitudinal observational study, 17 patients undergoing major liver resection for CRLM and 17 with benign indications as controls were enrolled. Liver regeneration within 30 postoperative days was assessed via CT, considering clinicopathological characteristics, liver enzymes, liver stiffness by elastography, and the impact of HGF and TGF-β1 on liver regeneration. The results revealed that the control group exhibited significantly higher mean liver regeneration volume (200 ± 180 mL) within 30 days postoperatively compared to the CRLM group (72 ± 154 mL); p = 0.03. Baseline alkaline phosphatase (AP) and TGF-β1 blood levels were notably higher in the CRLM group. Immunohistochemical analysis indicated a higher proportion of CRLM patients with high TGF-β1 expression in liver tissues compared to the control group (p = 0.034). Correlation analysis showed that resected liver volume, baseline plasma HGF, AP, and albumin levels significantly correlated with liver regeneration volume. However, in multivariable analysis, only resected liver volume (β: 0.31; 95% CI: 0.14-0.47, p = 0.01) remained significant. In conclusion, this study highlights compromised liver regeneration in CRLM patients post-chemotherapy. Additionally, these patients exhibited lower serum TGF-β1 levels and reduced TGF-β1 expression in liver tissue, suggesting TGF-β1 involvement in mechanisms hindering liver regeneration capacity following major resection after chemotherapy.

The role of ischaemia-reperfusion injury and liver regeneration in hepatic tumour recurrence

The risk of cancer recurrence after liver surgery mainly depends on tumour biology, but preclinical and clinical evidence suggests that the degree of perioperative liver injury plays a role in creating a favourable microenvironment for tumour cell engraftment or proliferation of dormant micro-metastases. Understanding the contribution of perioperative liver injury to tumour recurrence is imperative, as these pathways are potentially actionable. In this review, we examine the key mechanisms of perioperative liver injury, which comprise mechanical handling and surgical stress, ischaemia-reperfusion injury, and parenchymal loss leading to liver regeneration. We explore how these processes can trigger downstream cascades leading to the activation of the immune system and the pro-inflammatory response, cellular proliferation, angiogenesis, anti-apoptotic signals, and release of circulating tumour cells. Finally, we discuss the novel therapies under investigation to decrease ischaemia-reperfusion injury and increase regeneration after liver surgery, including pharmaceutical agents, inflow modulation, and machine perfusion.

Hepatectomy-induced apoptotic extracellular vesicles stimulate neutrophils to secrete regenerative growth factors

BACKGROUND & AIMS

Surgical resection of the cancerous tissue represents one of the few curative treatment options for neoplastic liver disease. Such partial hepatectomy (PHx) induces hepatocyte hyperplasia, which restores liver function. PHx is associated with bacterial translocation, leading to an immediate immune response involving neutrophils and macrophages, which are indispensable for the priming phase of liver regeneration. Additionally, PHx induces longer-lasting intrahepatic apoptosis. Herein, we investigated the effect of apoptotic extracellular vesicles (aEVs) on neutrophil function and their role in this later phase of liver regeneration.

METHODS

A total of 124 patients undergoing PHx were included in this study. Blood levels of the apoptosis marker caspase-cleaved cytokeratin-18 (M30) and circulating aEVs were analyzed preoperatively and on the first and fifth postoperative days. Additionally, the in vitro effects of aEVs on the secretome, phenotype and functions of neutrophils were investigated.

RESULTS

Circulating aEVs increased at the first postoperative day and were associated with higher concentrations of M30, which was only observed in patients with complete liver recovery. Efferocytosis of aEVs by neutrophils induced an activated phenotype (CD11bhighCD16highCD66bhighCD62Llow); however, classical inflammatory responses such as NETosis, respiratory burst, degranulation, or secretion of pro-inflammatory cytokines were not observed. Instead, efferocytosing neutrophils released various growth factors including fibroblast growth factor-2 and hepatocyte growth factor (HGF). Accordingly, we observed an increase of HGF-positive neutrophils after PHx and a correlation of plasma HGF with M30 levels.

CONCLUSIONS

These data suggest that the clearance of PHx-induced aEVs leads to a population of non-inflammatory but regenerative neutrophils, which may support human liver regeneration.

LAY SUMMARY

In this study, we show that the surgical removal of a diseased part of the liver triggers a specific type of programmed cell death in the residual liver tissue. This results in the release of vesicles from dying cells into the blood, where they are cleared by circulating immune cells. These respond by secreting hepatocyte growth factors that could potentially support the regeneration of the liver remnant.

Predicting liver regeneration following major resection

Breakdown of synthesis, excretion and detoxification defines liver failure. Post-hepatectomy liver failure (PHLF) is specific for liver resection and a rightfully feared complication due to high lethality and limited therapeutic success. Individual cytokine and growth factor profiles may represent potent predictive markers for recovery of liver function. We aimed to investigate these profiles in post-hepatectomy regeneration. This study combined a time-dependent cytokine and growth factor profiling dataset of a training (30 patients) and a validation (14 patients) cohorts undergoing major liver resection with statistical and predictive models identifying individual pathway signatures. 2319 associations were tested. Primary hepatocytes isolated from patient tissue samples were stimulated and their proliferation was analysed through DNA content assay. Common expression trajectories of cytokines and growth factors with strong correlation to PHLF, morbidity and mortality were identified despite highly individual perioperative dynamics. Especially, dynamics of EGF, HGF, and PLGF were associated with mortality. PLGF was additionally associated with PHLF and complications. A global association-network was calculated and validated to investigate interdependence of cytokines and growth factors with clinical attributes. Preoperative cytokine and growth factor signatures were identified allowing prediction of mortality following major liver resection by regression modelling. Proliferation analysis of corresponding primary human hepatocytes showed associations of individual regenerative potential with clinical outcome. Prediction of PHLF was possible on as early as first postoperative day (POD1) with AUC above 0.75. Prediction of PHLF and mortality is possible on POD1 with liquid-biopsy based risk profiling. Further utilization of these models would allow tailoring of interventional strategies according to individual profiles.

HGF/c-Met: A Key Promoter in Liver Regeneration

Hepatocyte growth factor (HGF) is a peptide-containing multifunctional cytokine that acts on various epithelial cells to regulate cell growth, movement and morphogenesis, and tissue regeneration of injured organs. HGF is sequestered by heparin-like protein in its inactive form and is widespread in the extracellular matrix of most tissues. When the liver loses its average mass, volume, or physiological and biochemical functions due to various reasons, HGF binds to its specific receptor c-Met (cellular mesenchymal-epithelial transition) and transmits the signals into the cells, and triggers the intrinsic kinase activity of c-Met. The downstream cascades of HGF/c-Met include JAK/STAT3, PI3K/Akt/NF-κB, and Ras/Raf pathways, affecting cell proliferation, growth, and survival. HGF has important clinical significance for liver fibrosis, hepatocyte regeneration after inflammation, and liver regeneration after transplantation. And the development of HGF as a biological drug for regenerative therapy of diseases, that is, using recombinant human HGF protein to treat disorders in clinical trials, is underway. This review summarizes the recent findings of the HGF/c-Met signaling functions in liver regeneration.

Value of Liver Function Tests in Cirrhosis

The liver comprises both parenchymal and non-parenchymal cells with varying functions. Cirrhosis is often complicated by the development of portal hypertension and its associated complications. Hence, assessment of liver in cirrhosis should include assessment of its structural, function of both hepatic and non-hepatic tissue and haemodynamic assessment of portal hypertension. There is no single test that can evaluate all functions of liver and assess prevalence and severity of portal hypertension. Commonly available tests like serum bilirubin, liver enzymes (alanine [ALT] and aspartate aminotransferase [AST], serum alkaline phosphatase [ALP], gamma glutamyl transpeptidase [GGT]), serum albumin and prothrombin time for assessment of liver functions partly assess liver functions. quantitative liver functions like indocyanine clearance tests [ICG-K], methacetin breath test [MBT] were developed to assess dynamic status of liver but has its own limitation and availability. Imaging based assessment of liver by transient elastography, MRI based 99 mTc-coupled asialoglycoprotein mebrofenin scan help the clinician to assess liver function, functional volume of liver left after surgery and portal hypertension [PH]. Hepatic venous pressure gradient still remains the gold standard for the assessment of portal hypertension but is invasive and not available in all centres. Combinations of blood parameters in form of various indices like fibrosis score of 4 [FIB-4], Lok index, scores like model for end stage liver disease (MELD) and Child-Turcotte Pugh score are commonly used for assessing liver function in clinical practice.

Liver transplantation for non-resectable colorectal liver metastases: the International Hepato-Pancreato-Biliary Association consensus guidelines

Colorectal cancer is a prevalent disease worldwide, with more than 50% of patients developing metastases to the liver. Despite advances in improving resectability, most patients present with non-resectable colorectal liver metastases requiring palliative systemic therapy and locoregional disease control strategies. There is a growing interest in the use of liver transplantation to treat non-resectable colorectal liver metastases in well selected patients, leading to a surge in the number of studies and prospective trials worldwide, thereby fuelling the emerging field of transplant oncology. The interdisciplinary nature of this field requires domain-specific evidence and expertise to be drawn from multiple clinical specialities and the basic sciences. Importantly, the wider societal implication of liver transplantation for non-resectable colorectal liver metastases, such as the effect on the allocation of resources and national transplant waitlists, should be considered. To address the urgent need for a consensus approach, the International Hepato-Pancreato-Biliary Association commissioned the Liver Transplantation for Colorectal liver Metastases 2021 working group, consisting of international leaders in the areas of hepatobiliary surgery, colorectal oncology, liver transplantation, hepatology, and bioethics. The aim of this study was to standardise nomenclature and define management principles in five key domains: patient selection, evaluation of biological behaviour, graft selection, recipient considerations, and outcomes. An extensive literature review was done within the five domains identified. Between November, 2020, and January, 2021, a three-step modified Delphi consensus process was undertaken by the workgroup, who were further subgrouped into the Scientific Committee, Expert Panel, and Transplant Centre Representatives. A final consensus of 44 statements, standardised nomenclature, and a practical management algorithm is presented. Specific criteria for clinico-patho-radiological assessments with molecular profiling is crucial in this setting. After this, the careful evaluation of biological behaviour with bridging therapy to transplantation with an appropriate assessment of the response is required. The sequencing of treatment in synchronous metastatic disease requires special consideration and is highlighted here. Some ethical dilemmas within organ allocation for malignant indications are discussed and the role for extended criteria grafts, living donor transplantation, and machine perfusion technologies for non-resectable colorectal liver metastases are reviewed. Appropriate immunosuppressive regimens and strategies for the follow-up and treatment of recurrent disease are proposed. This consensus guideline provides a framework by which liver transplantation for non-resectable colorectal liver metastases might be safely instituted and is a meaningful step towards future evidenced-based practice for better patient selection and organ allocation to improve the survival for patients with this disease.

Hepatic Arterioportal Fistula Is Associated with Decreased Future Liver Remnant Regeneration after Stage-I ALPPS for Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) patients often developed hepatic arterioportal fistula (APF). The aim of this study is to evaluate the impact of APF on future liver remnant (FLR) regeneration and surgical outcomes after the first stage of associating liver partition and portal vein ligation for staged hepatectomy (stage-I ALPPS).

METHODS

Consecutive HCC patients who underwent ALPPS at our center between March 2017 and May 2019 were retrospectively studied. Data for the association between APF and clinicopathological details, liver volume, and surgical outcomes were analyzed.

RESULTS

The enrolled 35 HCC patients were divided into three groups: 15 patients with preoperative APF were classified as the APF I group, 10 patients developed APF after stage-I ALPPS as the APF II group, whereas the other 10 patients without APF before and after stage-I ALPPS as the control group. After stage-I ALPPS, patients in the APF I and APF II groups had lower kinetic growth rate (KGR) of FLR volume (6.1±3.2%, 11.4±8.4%, 25.0±8.8% per week, respectively, P<0.001) and took longer median time to reach the sufficient FLR volume for stage-II ALPPS (17.5 days, 12 days, 6 days, respectively, P<0.001) than those in the control group. Meanwhile, the incidence of posthepatectomy liver failure (PHLF) in the APF I and APF II groups was significantly higher than that of the control group (P=0.007). There are 27 (77.1%) patients who completed stage-II ALPPS. The overall survival (OS) rates at 1 and 3 years were 59.3% and 35.1%, whereas the disease-free survival (DFS) rates at 1 and 3 years were 44.4% and 22.9%, respectively.

CONCLUSIONS

Hepatic APF is significantly associated with decreased FLR regeneration and a higher risk of PHLF after stage-I ALPPS. HCC patients who are to undergo ALPPS may benefit from the timely perioperative intervention of APF.

Influence of cytokines, circulating markers and growth factors on liver regeneration and post-hepatectomy liver failure: a systematic review and meta-analysis

The pathophysiology of post-hepatectomy liver failure is not entirely understood but is rooted in the disruption of normal hepatocyte regeneration and homeostasis. Current investigations of post-hepatectomy liver failure and regeneration are focused on evaluation of circulating hepatic function parameters (transaminases, cholestasis, and coagulation parameters), volumetry and hepatic hemodynamics. However, identification of biochemical factors associated with regeneration and post hepatectomy liver failure is crucial for understanding the pathophysiology and identification of patients at risk. The objective of the present systematic review was to identify circulating factors associated with liver regeneration and post hepatectomy liver failure in patients undergoing hepatectomy. The quantitative analysis was intended if studies provided sufficient data. Electronic databases (MEDLINE via PubMed, Web of Knowledge, Cochrane Library and WHO International Clinical Trials Registry Platform) were searched for publications on cell signaling factors in liver regeneration and post-hepatectomy liver failure following liver resection in clinical setting. No date restriction was given. No language restriction was used. Studies were assessed using MINORS. This study was registered at PROSPERO (CRD42020165384) prior to data extraction. In total 1953 publications were evaluated for titles and abstracts after exclusion of duplicates. Full texts of 167 studies were further evaluated for inclusion. 26 articles were included in the review and 6 publications were included in the meta-analyses. High levels of serum hyaluronic acid even preoperatively are associated with PHLF but especially increased levels early after resection are predictive of PHLF with high sensitivity and specificity. Postoperative elevation of HA to levels between 100 and 500 ng/ml is increased the risk for PHLF ([OR] = 246.28, 95% [CI]: 11.82 to 5131.83; p = 0.0004) Inteleukin-6 levels show contradicting result in association with organ dysfunction. HGF positively correlates with liver regeneration. Overall, due to heterogeneity, scarcity, observational study design and largely retrospective analysis, the certainty of evidence, assessed with GRADE, is very low. High levels of serum hyaluronic acid show a strong association with PHLF and increased levels after resection are predictive of PHLF with high sensitivity and specificity, even on POD1. Interleukin-6 levels need to be studied further due to contradictive results in association with organ dysfunction. For HGF, no quantitative analysis could be made. Yet, most studies find positive correlation between high HGF levels and regeneration. Prospective studies investigating HGF and other growth factors, hyaluronic acid and interleukins 1 and 6 in correlation with liver regeneration measured sequentially through e.g. volumetry, and liver function parameters, preferably expanding the analysis to include dynamic liver function tests, are needed to sufficiently illustrate the connection between biomolecule levels and clinical outcomes.

Markers of liver regeneration-the role of growth factors and cytokines: a systematic review

BACKGROUND

Post-hepatectomy liver failure contributes significantly to postoperative mortality after liver resection. The prediction of the individual risk for liver failure is challenging. This review aimed to provide an overview of cytokine and growth factor triggered signaling pathways involved in liver regeneration after resection.

METHODS

MEDLINE and Cochrane databases were searched without language restrictions for articles from the time of inception of the databases till March 2019. All studies with comparative data on the effect of cytokines and growth factors on liver regeneration in animals and humans were included.

RESULTS

Overall 3.353 articles comprising 40 studies involving 1.498 patients and 101 animal studies were identified and met the inclusion criteria. All included trials on humans were retrospective cohort/observational studies. There was substantial heterogeneity across all included studies with respect to the analyzed cytokines and growth factors and the described endpoints.

CONCLUSION

High-level evidence on serial measurements of growth factors and cytokines in blood samples used to predict liver regeneration after resection is still lacking. To address the heterogeneity of patients and potential markers, high throughput serial analyses may offer a method to predict an individual's regenerative potential in the future.