Exploration of the Transcriptional Landscape of ALPPS Reveals the Pathways of Accelerated Liver Regeneration

Simultaneous portal and hepatic vein embolization is better than portal embolization or ALPPS for hypertrophy of future liver remnant before major hepatectomy: A systematic review and network meta-analysis

BACKGROUND

Post-hepatectomy liver failure (PHLF) is the Achilles' heel of hepatic resection for colorectal liver metastases. The most commonly used procedure to generate hypertrophy of the functional liver remnant (FLR) is portal vein embolization (PVE), which does not always lead to successful hypertrophy. Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been proposed to overcome the limitations of PVE. Liver venous deprivation (LVD), a technique that includes simultaneous portal and hepatic vein embolization, has also been proposed as an alternative to ALPPS. The present study aimed to conduct a systematic review as the first network meta-analysis to compare the efficacy, effectiveness, and safety of the three regenerative techniques.

DATA SOURCES

A systematic search for literature was conducted using the electronic databases Embase, PubMed (MEDLINE), Google Scholar and Cochrane.

RESULTS

The time to operation was significantly shorter in the ALPPS cohort than in the PVE and LVD cohorts by 27 and 22 days, respectively. Intraoperative parameters of blood loss and the Pringle maneuver demonstrated non-significant differences between the PVE and LVD cohorts. There was evidence of a significantly higher FLR hypertrophy rate in the ALPPS cohort when compared to the PVE cohort, but non-significant differences were observed when compared to the LVD cohort. Notably, the LVD cohort demonstrated a significantly better FLR/body weight (BW) ratio compared to both the ALPPS and PVE cohorts. Both the PVE and LVD cohorts demonstrated significantly lower major morbidity rates compared to the ALPPS cohort. The LVD cohort also demonstrated a significantly lower 90-day mortality rate compared to both the PVE and ALPPS cohorts.

CONCLUSIONS

LVD in adequately selected patients may induce adequate and profound FLR hypertrophy before major hepatectomy. Present evidence demonstrated significantly lower major morbidity and mortality rates in the LVD cohort than in the ALPPS and PVE cohorts.

Hepatectomy-Induced Alterations in Hepatic Perfusion and Function - Toward Multi-Scale Computational Modeling for a Better Prediction of Post-hepatectomy Liver Function

Liver resection causes marked perfusion alterations in the liver remnant both on the organ scale (vascular anatomy) and on the microscale (sinusoidal blood flow on tissue level). These changes in perfusion affect hepatic functions via direct alterations in blood supply and drainage, followed by indirect changes of biomechanical tissue properties and cellular function. Changes in blood flow impose compression, tension and shear forces on the liver tissue. These forces are perceived by mechanosensors on parenchymal and non-parenchymal cells of the liver and regulate cell-cell and cell-matrix interactions as well as cellular signaling and metabolism. These interactions are key players in tissue growth and remodeling, a prerequisite to restore tissue function after PHx. Their dysregulation is associated with metabolic impairment of the liver eventually leading to liver failure, a serious post-hepatectomy complication with high morbidity and mortality. Though certain links are known, the overall functional change after liver surgery is not understood due to complex feedback loops, non-linearities, spatial heterogeneities and different time-scales of events. Computational modeling is a unique approach to gain a better understanding of complex biomedical systems. This approach allows (i) integration of heterogeneous data and knowledge on multiple scales into a consistent view of how perfusion is related to hepatic function; (ii) testing and generating hypotheses based on predictive models, which must be validated experimentally and clinically. In the long term, computational modeling will (iii) support surgical planning by predicting surgery-induced perfusion perturbations and their functional (metabolic) consequences; and thereby (iv) allow minimizing surgical risks for the individual patient. Here, we review the alterations of hepatic perfusion, biomechanical properties and function associated with hepatectomy. Specifically, we provide an overview over the clinical problem, preoperative diagnostics, functional imaging approaches, experimental approaches in animal models, mechanoperception in the liver and impact on cellular metabolism, omics approaches with a focus on transcriptomics, data integration and uncertainty analysis, and computational modeling on multiple scales. Finally, we provide a perspective on how multi-scale computational models, which couple perfusion changes to hepatic function, could become part of clinical workflows to predict and optimize patient outcome after complex liver surgery.

Integrin Linked Kinase (ILK) and its Role in Liver Pathobiology

Integrin linked kinase (ILK) is a vital signaling protein ubiquitously expressed throughout the body. It binds to intracellular integrins to help promote signaling related to cell adhesion, apoptosis, proliferation, migration, and a plethora of other common cellular functions. In this review, ILKs role in the liver is detailed. Studies have shown ILK to be a major participant in hepatic ECM organization, liver regeneration, insulin resistance, and hepatocellular carcinoma.

Conversion to Resectability Using Transarterial Chemoembolization Combined With Hepatic Arterial Infusion Chemotherapy for Initially Unresectable Hepatocellular Carcinoma

Objective

To evaluate whether this conversion rate to resectability could be increased when patients are treated with transarterial chemoembolization and hepatic arterial infusion chemotherapy (TACE-HAIC) using oxaliplatin plus fluorouracil/leucovorin.

Background

Conventional TACE (c-TACE) is a common regimen for initially unresectable hepatocellular carcinoma (HCC), which converts to curative-intent resection in about 10% of those patients. It is urgent need to investigated better regimen for those patients.

Methods

The data of 83 initially unresectable HCC patients were examined, including 41 patients in the TACE-HAIC group and 42 patients in the c-TACE group. Their response rate, conversion rate to resection, survival outcome, and adverse events were compared.

Results

The conversion rate was significantly better in the TACE-HAIC group than in the c-TACE group (48.8% vs 9.5%; P < 0.001). The TACE-HAIC had marginal superiority in overall response rate as compared to c-TACE (14.6% vs 2.4%; P = 0.107 [RECIST]; 65.9% vs 16.7%; P < 0.001 [mRECIST], respectively). The median progression-free survival was not available and 9.2 months for the TACE-HAIC and cTACE groups, respectively (hazard rate [HR]: 0.38; 95% confidence interval [CI], 0.20-0.70; P = 0.003). The median overall survival was not available and 13.5 months for the TACE-HAIC and c-TACE groups, respectively (HR, 0.63; 95% CI, 0.34-1.17; P = 0.132). The 2 groups had similar rates of grade 3/4 adverse events (all P > 0.05).

Conclusions

TACE-HAIC demonstrated a higher conversion rate and progression-free survival benefit than c-TACE and could be considered as a more effective regimen for patients with initially unresectable HCC. Future prospective randomized trials are needed to confirm it.

Using proteomic and transcriptomic data to assess activation of intracellular molecular pathways

Analysis of molecular pathway activation is the recent instrument that helps to quantize activities of various intracellular signaling, structural, DNA synthesis and repair, and biochemical processes. This may have a deep impact in fundamental research, bioindustry, and medicine. Unlike gene ontology analyses and numerous qualitative methods that can establish whether a pathway is affected in principle, the quantitative approach has the advantage of exactly measuring the extent of a pathway up/downregulation. This results in emergence of a new generation of molecular biomarkers-pathway activation levels, which reflect concentration changes of all measurable pathway components. The input data can be the high-throughput proteomic or transcriptomic profiles, and the output numbers take both positive and negative values and positively reflect overall pathway activation. Due to their nature, the pathway activation levels are more robust biomarkers compared to the individual gene products/protein levels. Here, we review the current knowledge of the quantitative gene expression interrogation methods and their applications for the molecular pathway quantization. We consider enclosed bioinformatic algorithms and their applications for solving real-world problems. Besides a plethora of applications in basic life sciences, the quantitative pathway analysis can improve molecular design and clinical investigations in pharmaceutical industry, can help finding new active biotechnological components and can significantly contribute to the progressive evolution of personalized medicine. In addition to the theoretical principles and concepts, we also propose publicly available software for the use of large-scale protein/RNA expression data to assess the human pathway activation levels.

Mitochondrial dysfunction attenuates rapid regeneration in livers with toxin-induced fibrosis

BACKGROUND

The mechanism of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS)-induced rapid liver regeneration remains poorly documented, especially in patients with fibrosis. Therefore, this study aims to investigate the underlying mechanism of ALPPS-induced accelerated regeneration in toxin-induced fibrosis models.

METHODS

The ALPPS-induced regeneration model was established in livers with thioacetamide (TAA)-induced fibrosis to determine the regenerative pathways involved in rapid regeneration. Confirmatory experiments were performed in transforming growth factor beta 1 (TGFβ1)-treated AML12 cells and mice with carbon tetrachloride (CCl4)-induced fibrosis. Finally, mitochondrial dysfunction was validated in fibrotic/non-fibrotic patients.

RESULTS

In TAA-induced fibrotic mice, ALPPS-induced regeneration was significantly inferior to that of the control group (P=0.027 at day 2 and P<0.001 at day 7). Furthermore, mitochondria-associated genes were significantly downregulated in TAA-challenged mice. Accordingly, the reduced production of ATP and elevated levels of malondialdehyde indicated disturbances in intracellular energy metabolism during the ALPPS-induced regenerative process after TAA treatment. Further investigations were performed in TGF-β1-treated AML12 cells and CCl4-treated mice, which indicated that mitochondrial dysfunction attenuated the capacity for rapid regeneration after ALPPS.

CONCLUSIONS

In summary, this study revealed that mitochondrial dysfunction led to inferior regeneration in livers with toxin-induced fibrosis and identified new therapeutic targets to improve the feasibility and safety of the ALPPS procedure. Further studies in human patients are required in the future.

Conventional Two-Stage Hepatectomy or Associating Liver Partitioning and Portal Vein Ligation for Staged Hepatectomy for Colorectal Liver Metastases? A Systematic Review and Meta-Analysis

Background: Pushing the surgical limits for initially unresectable colorectal liver metastases (CRLM) are two approaches for sequential liver resection: two-stage hepatectomy (TSH) and associating liver partitioning and portal vein ligation for staged hepatectomy (ALPPS). However, the role of each treatment modality remains ill-defined. The present meta-analysis was designed to compare the safety, efficacy, and oncological benefits between ALPPS and TSH in the management of advanced CRLM.

Methods: A systematic literature search was conducted from online databases through to February 2020. Single-arm synthesis and cumulative meta-analysis were performed.

Results: Eight studies were included, providing a total of 409 subjects for analysis (ALPPS: N = 161; TSH: N = 248). The completions of the second stage of the hepatectomy [98 vs. 78%, odds ratio (OR) 5.75, p < 0.001] and R0 resection (66 vs. 37%; OR 4.68; p < 0.001) were more frequent in patients receiving ALPPS than in those receiving TSH, and the waiting interval was dramatically shortened in ALPPS (11.6 vs. 45.7 days, weighted mean difference = −35.3 days, p < 0.001). Nevertheless, the rate of minor complications was significantly higher in ALPPS (59 vs. 18%, OR 6.5, p < 0.001) than in TSH. The two treatments were similar in 90-day mortality (7 vs. 5%, p = 0.43), major complications (29 vs. 22%, p = 0.08), posthepatectomy liver failure (PHLF; 9 vs. 9%, p = 0.3), biliary leakage (11 vs. 14%, p = 0.86), length of hospital stay (27.95 vs. 26.88 days, p = 0.8), 1-year overall survival (79 vs. 84%, p = 0.61), 1-year recurrence (49 vs. 39%, p = 0.32), and 1-year disease-free survival (34 vs. 39%, p = 0.66). Cumulative meta-analyses indicated chronological stability for the pooled effect sizes of resection rate, 90-day mortality, major complications, and PHLF.

Conclusions: Compared with TSH, ALPPS for advanced CRLM resulted in superior surgical efficacy with comparable perioperative mortality rate and short-term oncological outcomes, while this was at the cost of increased perioperative minor complications.

Clinical translation of liver regeneration therapies: A conceptual road map

The increasing incidence of severe liver diseases worldwide has resulted in a high demand for curative liver transplantation. Unfortunately, the need for transplants by far eclipses the availability of suitable grafts leaving many waitlisted patients to face liver failure and often death. Routine use of smaller grafts (for example left lobes, split livers) from living or deceased donors could increase the number of life-saving transplants but is often limited by the graft versus recipient weight ratio defining the safety margins that minimize the risk of small for size syndrome (SFSS). SFSS is a severe complication characterized by failure of a small liver graft to regenerate and occurs when a donor graft is insufficient to meet the metabolic demand of the recipient, leading to liver failure as a result of insufficient liver mass. SFSS is not limited to transplantation but can also occur in the setting of hepatic surgical resections, where life-saving large resections of tumors may be limited by concerns of post-surgical liver failure. There are, as yet no available pro-regenerative therapies to enable liver regrowth and thus prevent SFSS. However, there is optimism around targeting factors and pathways that have been identified as regulators of liver regeneration to induce regrowth in vivo and ex vivo for clinical use. In this commentary, we propose a roadmap for developing such pro-regenerative therapy and for bringing it into the clinic. We summarize the clinical indications, preclinical models, pro-regenerative pathways and safety considerations necessary for developing such a drug.