Single administration of thrombopoietin prevents progression of liver fibrosis and promotes liver regeneration after partial hepatectomy in cirrhotic rats. Ann Surg. 2008;248:821-828. [PMID: 18948810 DOI: 10.1097/sla.0b013e31818584c7]

Aspirin suppresses hepatocellular carcinoma progression by inhibiting platelet activity

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common malignant liver disease in the world. Platelets (PLTs) are known to play a key role in the maintenance of liver homeostasis and the pathophysiological processes of a variety of liver diseases. Aspirin is the most classic antiplatelet agent. However, the molecular mechanism of platelet action and whether aspirin can affect HCC progression by inhibiting platelet activity need further study.

AIM

To explore the impact of the antiplatelet effect of aspirin on the development of HCC.

METHODS

Platelet-rich plasma, platelet plasma, pure platelet, and platelet lysate were prepared, and a coculture model of PLTs and HCC cells was established. CCK-8 analysis, apoptosis analysis, Transwell analysis, and real-time polymerase chain reaction (RT-PCR) were used to analyze the effects of PLTs on the growth, metastasis, and inflammatory microenvironment of HCC. RT-PCR and Western blot were used to detect the effects of platelet activation on tumor-related signaling pathways. Aspirin was used to block the activation and aggregation of PLTs both in vitro and in vivo, and the effect of PLTs on the progression of HCC was detected.

RESULTS

PLTs significantly promoted the growth, invasion, epithelial-mesenchymal transition, and formation of an inflammatory microenvironment in HCC cells. Activated PLTs promoted HCC progression by activating the mitogen-activated protein kinase/protein kinase B/signal transducer and activator of transcription three (MAPK/ AKT/STAT3) signaling axis. Additionally, aspirin inhibited HCC progression in vitro and in vivo by inhibiting platelet activation.

CONCLUSION

PLTs play an important role in the pathogenesis of HCC, and aspirin can affect HCC progression by inhibiting platelet activity. These results suggest that antiplatelet therapy has promising application prospects in the treatment and combined treatment of HCC.

Aspirin suppresses hepatocellular carcinoma progression by inhibiting platelet activity

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common malignant liver disease in the world. Platelets (PLTs) are known to play a key role in the maintenance of liver homeostasis and the pathophysiological processes of a variety of liver diseases. Aspirin is the most classic antiplatelet agent. However, the molecular mechanism of platelet action and whether aspirin can affect HCC progression by inhibiting platelet activity need further study.

AIM

To explore the impact of the antiplatelet effect of aspirin on the development of HCC.

METHODS

Platelet-rich plasma, platelet plasma, pure platelet, and platelet lysate were prepared, and a coculture model of PLTs and HCC cells was established. CCK-8 analysis, apoptosis analysis, Transwell analysis, and real-time polymerase chain reaction (RT-PCR) were used to analyze the effects of PLTs on the growth, metastasis, and inflammatory microenvironment of HCC. RT-PCR and Western blot were used to detect the effects of platelet activation on tumor-related signaling pathways. Aspirin was used to block the activation and aggregation of PLTs both in vitro and in vivo, and the effect of PLTs on the progression of HCC was detected.

RESULTS

PLTs significantly promoted the growth, invasion, epithelial-mesenchymal transition, and formation of an inflammatory microenvironment in HCC cells. Activated PLTs promoted HCC progression by activating the mitogen-activated protein kinase/protein kinase B/signal transducer and activator of transcription three (MAPK/ AKT/STAT3) signaling axis. Additionally, aspirin inhibited HCC progression in vitro and in vivo by inhibiting platelet activation.

CONCLUSION

PLTs play an important role in the pathogenesis of HCC, and aspirin can affect HCC progression by inhibiting platelet activity. These results suggest that antiplatelet therapy has promising application prospects in the treatment and combined treatment of HCC.

New and Old Key Players in Liver Cancer

Liver cancer represents a major health problem worldwide with growing incidence and high mortality, hepatocellular carcinoma (HCC) being the most frequent. Hepatocytes are likely the cellular origin of most HCCs through the accumulation of genetic alterations, although hepatic progenitor cells (HPCs) might also be candidates in specific cases, as discussed here. HCC usually develops in a context of chronic inflammation, fibrosis, and cirrhosis, although the role of fibrosis is controversial. The interplay between hepatocytes, immune cells and hepatic stellate cells is a key issue. This review summarizes critical aspects of the liver tumor microenvironment paying special attention to platelets as new key players, which exert both pro- and anti-tumor effects, determined by specific contexts and a tight regulation of platelet signaling. Additionally, the relevance of specific signaling pathways, mainly HGF/MET, EGFR and TGF-β is discussed. HGF and TGF-β are produced by different liver cells and platelets and regulate not only tumor cell fate but also HPCs, inflammation and fibrosis, these being key players in these processes. The role of C3G/RAPGEF1, required for the proper function of HGF/MET signaling in HCC and HPCs, is highlighted, due to its ability to promote HCC growth and, regulate HPC fate and platelet-mediated actions on liver cancer.

Nomogram to predict liver surgery-specific complications for hepatocellular carcinoma: A multicenter study

BACKGROUND

Early identification of patients at risk for surgical complications enables surgeons to make better treatment decisions and optimize resource utilization. We propose to develop a nomogram for predicting the risk of moderate-to-severe liver surgery-specific complications after hepatectomy in hepatocellular carcinoma (HCC) patients.

METHODS

We retrospectively enrolled HCC patients who underwent radical hepatectomy at four medical centers from January 2014 to January 2019 in southwestern China, randomly (7:3) divided into training and validation cohorts. We used least absolute shrinkage and selection operator (LASSO) logistic regression to build a nomogram model.

RESULTS

The nomogram model contained 6 variables: diabetes mellitus (yes vs. no, OR: 2.32, 95% CI: 1.16-4.64, P = 0.02), major hepatectomy (yes vs. no, OR: 2.65, 95% CI: 1.64-4.27, P < 0.001), platelets (PLT, ≥100 × 103/μl vs. <100 × 103/μl, OR: 0.53, 95% CI: 0.33-0.87, P = 0.01), prothrombin time (PT, >13 s vs. ≤13 s, OR: 1.78, 95% CI: 1.04-3.05, P = 0.04), albumin-indocyanine green evaluation grade (ALICE grade, grade B vs. grade A, OR: 2.06, 95% CI: 1.17-3.61, P = 0.01), and prognostic nutrient index (PNI, >48 vs. ≤48, OR: 0.55, 95% CI: 0.33-0.92, P = 0.02). The concordance index (C-index) and area under the receiver operating characteristic curve (AUC) were 0.751 (95% CI, 0.703-0.799) and 0.743 (95% CI, 0.653-0.833) for the training and validation cohorts, respectively. Decision curve analysis (DCA) showed that the nomogram had good clinical value.

CONCLUSION

We provide good preoperative predictors for the risk of moderate-to-high FABIB score complications in patients with HBV-related HCC posthepatectomy.

Effects of thrombopoietin pre-treatment on peri-liver transplantation thrombocytopenia in a mouse model of cirrhosis with hypersplenism

BACKGROUND

During cirrhosis, the liver is impaired and unable to synthesize and clear thrombopoietin properly. At the same time, the spleen assumes the function of hemofiltration and storage due to liver dysfunction, resulting in hypersplenism and excessive removal of platelets in the spleen, further reducing platelet count. When liver function is decompensated in cirrhotic patients, the decrease of thrombopoietin (TPO) synthesis is the main reason for the decrease of new platelet production. This change of TPO leads to thrombocytopenia and bleeding tendency in cirrhotic patients with hypersplenism.

AIM

To investigate the clinical efficacy of recombinant human TPO (rhTPO) in the treatment of perioperative thrombocytopenia during liver transplantation in cirrhotic mice with hypersplenism.

METHODS

C57BL/6J mice and TPO receptor-deficient mice were used to establish models of cirrhosis with hypersplenism. Subsequently, these mice underwent orthotopic liver transplantation (OLT). The mice in the experimental group were given rhTPO treatment for 3 consecutive days before surgery and 5 consecutive days after surgery, while the mice in the control group received the same dose of saline at the same frequency. Differences in liver function and platelet counts were determined between the experimental and control groups. Enzyme-linked immunosorbent assay was used to assess the expression of TPO and TPO receptor (c-Mpl) in the blood.

RESULTS

Preoperative administration of rhTPO significantly improved peri-OLT thrombocytopenia in mice with cirrhosis and hypersplenism. Blocking the expression of TPO receptors exacerbated peri-OLT thrombocytopenia. The concentration of TPO decreased while the concentration of c-Mpl increased in compensation in the mouse model of cirrhosis with hypersplenism. TPO pre-treatment significantly increased the postoperative TPO concentration in mice, which in turn led to a decrease in the c-Mpl concentration. TPO pre-treatment also significantly enhanced the Janus kinase (Jak)/signal transducers and activators of transcription pathway protein expressions in bone marrow stem cells of the C57BL/6J mice. Moreover, the administration of TPO, both before and after surgery, regulated the levels of biochemical indicators, such as alanine aminotransferase, alkaline phosphatase, and aspartate aminotransferase in the C57BL/6J mice.

CONCLUSION

Pre-treatment with TPO not only exhibited therapeutic effects on perioperative thrombocytopenia in the mice with cirrhosis and hypersplenism, who underwent liver transplantation but also significantly enhanced the perioperative liver function.

Microvascular Thrombosis and Liver Fibrosis Progression: Mechanisms and Clinical Applications

Fibrosis is an unavoidable consequence of chronic inflammation. Extracellular matrix deposition by fibroblasts, stimulated by multiple pathways, is the first step in the onset of chronic liver disease, and its propagation promotes liver dysfunction. At the same time, chronic liver disease is characterized by alterations in primary and secondary hemostasis but unlike previously thought, these changes are not associated with an increased risk of bleeding complications. In recent years, the role of coagulation imbalance has been postulated as one of the main mechanisms promoting hepatic fibrogenesis. In this review, we aim to investigate the function of microvascular thrombosis in the progression of liver disease and highlight the molecular and cellular networks linking hemostasis to fibrosis in this context. We analyze the predictive and prognostic role of coagulation products as biomarkers of liver decompensation (ascites, variceal hemorrhage, and hepatic encephalopathy) and liver-related mortality. Finally, we evaluate the current evidence on the application of antiplatelet and anticoagulant therapies for prophylaxis of hepatic decompensation or prevention of the progression of liver fibrosis.

A double-edged sword of platelet-derived extracellular vesicles in tissues, injury or repair: The current research overview

Extracellular vesicles (EVs) are vesicular bodies with a double-layered membrane structure that are detached from the cell membrane or secreted by the cells. EVs secreted by platelets account for the main part in the blood circulation, which account for about 30% or even more. Many types of cells are regulated by PEVs, including endothelial cells, leukocytes, smooth muscle cells, etc. Nevertheless, despite the growing interest in the study of extracellular vesicles, there are still only a few studies on the role of PEVs. Therefore, this overview mainly focuses on one method of isolation and the functions of PEVs in tissues found so far, including promoting tissue repair and mediating tissue damage, which can be used for researchers to continue to explore the role of PEVs in other fields.

Risk Factors for Development of Biliary Stricture After Liver Transplant in Adult Patients: A Single-Center Retrospective Study

Identification of risk factors for biliary stricture after liver transplant and its potential prevention is crucial to improve the outcomes and reduce the complications. We retrospectively analyzed donor and recipient characteristics with intraoperative and postoperative parameters to identify the risk factors for development of post-transplant anastomotic and nonanastomotic biliary strictures with additional analysis of the time onset of those strictures. A total of 412 patients were included in this study. Mean (SD) follow-up time was 79 (35) months (range, 1-152 months). Biliary stricture was diagnosed in 84 patients (20.4%). Multivariate analysis indicated that postoperative biliary leakage (odd ratio [OR], 3.94; P = .001), acute cellular rejection (OR, 3.05; P < .001), donor age older than 47.5 years (OR, 2.05; P = .032), preoperative recipient platelet value < 77.5 × 10³/mL (OR, 1.91; P = .023), University of Wisconsin solution (OR, 1.73; P = .041)), recipient male sex (OR, 1.78; P = .072), portal/arterial flow ratio > 4 (OR, 1.76; P = .083), and intraoperative bleeding > 2850 mL (OR, 1.70; P = .053) were independent risk factors for biliary stricture regardless of the time of their appearance. Multiple risk factors for biliary stricture were determined in this study. Some of these risk factors are preventable, and implementation of strategies to eliminate some of those factors should reduce the development of post-transplant biliary stricture.

The Lactate-to-Platelet Ratio: A Novel Predictor for Short-Term Early Allograft Failure After Liver Transplantation

BACKGROUND

Early allograft dysfunction (EAD) is a criterion to evaluate initial graft dysfunction associated with inferior graft survival and postoperative complications after liver transplantation (LT). This study defined the lactate-to-platelet ratio (LPR) as lactate level immediately post-LT/platelet count on postoperative day 1 and evaluated its association with EAD and short-term graft failure.

MATERIALS AND METHODS

This study reviewed 434 deceased-donor LTs from individuals with confirmed brain death between January 2008 and December 2014. The area under the curve (AUC) was used to compare the predictive capacity for 3-month graft survival between EAD and the LPR. Along with LPR, the risk factors for 3-month graft failure were analyzed by multivariate analysis.

RESULTS

EAD was reported in 127 patients (31%). The LPR in patients with EAD was significantly higher than that in patients without EAD (9.8 vs 5.9, P < .001). In the multivariate analysis, both the LPR (per 1.0 increase) and EAD were independent risk factors for 3-month graft failure (hazard ratio [HR] =1.03, P = .03; and HR = 9.14, P = .001). The comparison of the AUCs between the LPR and EAD showed no significant difference (0.79 vs 0.78, P = .84), whereas the combination of EAD and LPR had a better predictive capacity than EAD alone (0.86 vs 0.78, P < .001). The LPR showed an inverse relationship for predicting 3-month graft survival.

CONCLUSIONS

The LPR is a continuous parameter that enables prediction of initial graft function and estimation of the 3-month graft failure rate with the advantages of early availability and simple calculations.

The Effect of the Platelet Administration for the Patients with Liver Dysfunction after Liver Resection: Preliminary Clinical Trial

The aim of this study is to investigate the effect of platelet on the improvement of deteriorated liver function after liver resection. Six patients with hepatocellular carcinoma and liver cirrhosis have received the partial hepatectomy in the institution. Their Child–Pugh grade was B, and platelet count was below 7,000/µl. After hepatectomy, 20 units of platelet transfusion were carried out, liver function and side effects were investigated after 4 weeks, and the number of platelets increased to approximately 15,000/µl. Liver functions, such as aspartate transaminase (AST), alanine aminotransferase (ALT), cholinesterase (ChE), and prothrombin time, as well as albumin, recover to the same level as those before operation and 4 weeks after the operation. Any side effects were not recognized in all patients. Administration of platelets for cirrhotic patient with hepatectomy was carried with safety. But remarkable effect on the improvement of liver function was not recognized.

Crosstalk between hepatic stellate cells and surrounding cells in hepatic fibrosis

Hepatic fibrosis represents as a dynamic pathological process characterized by the net accumulation of extracellular matrix in the progression of various chronic liver diseases, including viral hepatitis, alcoholic liver disease, and metabolic associated fatty liver disease (MAFLD). Activation of hepatic stellate cells (HSCs) is well-defined to play a central role in the initiation and progression of hepatic fibrosis. However, the activation of HSCs is affected by the complicated microenvironments in liver, which largely attributes to the communication between hepatocytes and multiple tissue-resident cells, including sinusoidal endothelial cells, bile duct epithelial cells, platelets, T cells, B cells, macrophages, natural killer cells, neutrophils, dendritic cells, in the direct or indirect mechanisms. Cellular crosstalk between HSCs and surrounding cells contributes to the activation of HSCs and the progression of hepatic fibrosis. Currently, accumulating evidence have proven the complexity and plasticity of HSCs activation, and further clarification of cellular communication between HSCs and surrounding cells will provide sufficient clue to the development of novel diagnostic methods and therapeutic strategies for hepatic fibrosis.

Till Death Do Us Part-The Multifaceted Role of Platelets in Liver Diseases

Platelets are tightly connected with the liver, as both their production and their clearance are mediated by the liver. Platelets, in return, participate in a variety of liver diseases, ranging from non-alcoholic fatty liver diseases, (viral) hepatitis, liver fibrosis and hepatocellular carcinoma to liver regeneration. Due to their versatile functions, which include (1) regulation of hemostasis, (2) fine-tuning of immune responses and (3) release of growth factors and cellular mediators, platelets quickly adapt to environmental changes and modulate disease development, leading to different layers of complexity. Depending on the (patho)physiological context, platelets exert both beneficial and detrimental functions. Understanding the precise mechanisms through which platelet function is regulated at different stages of liver diseases and how platelets interact with various resident and non-resident liver cells helps to draw a clear picture of platelet-related therapeutic interventions. Therefore, this review summarizes the current knowledge on platelets in acute and chronic liver diseases and aims to shed light on how the smallest cells in the circulatory system account for changes in the (patho)physiology of the second largest organ in the human body.

Hemostasis and Liver Regeneration

The liver is unique in its remarkable regenerative capacity, which enables the use of liver resection as a treatment for specific liver diseases, including removal of neoplastic liver disease. After resection, the remaining liver tissue (i.e, liver remnant) regenerates to maintain normal hepatic function. In experimental settings as well as patients, removal of up to two-thirds of the liver mass stimulates a rapid and highly coordinated process resulting in the regeneration of the remaining liver. Mechanisms controlling the initiation and termination of regeneration continue to be discovered, and many of the fundamental signaling pathways controlling the proliferation of liver parenchymal cells (i.e., hepatocytes) have been uncovered. Interestingly, while hemostatic complications (i.e., bleeding and thrombosis) are primarily thought of as a complication of surgery itself, strong evidence suggests that components of the hemostatic system are, in fact, powerful drivers of liver regeneration. This review focuses on the clinical and translational evidence supporting a link between the hemostatic system and liver regeneration, and the mechanisms whereby the hemostatic system directs liver regeneration discovered using experimental settings.

The value of platelet count in evaluating the degree of liver fibrosis in patients with chronic hepatitis B

Objective

To investigate the value of platelet count in evaluating the degree of liver fibrosis in patients with chronic hepatitis B (CHB).

Methods

A total of 158 CHB patients who underwent liver biopsy in our hospital were included, and the clinical characteristics of these patients were retrospectively analyzed. The diagnostic values of platelet count, aspartate aminotransferase‐to‐platelet ratio index (APRI), and the fibrosis index based on four factors (FIB‐4) for significant fibrosis (F ≥ 2) and early cirrhosis (F = 4) stages in CHB patients were assessed by the use of receiver operating characteristic (ROC) analysis.

Results

The median (F0: 221.0; F1: 210.0; F2: 188.0; F3: 171.0; and F4: 155.5) and mean rank (F0: 120.4; F1: 100.1; F2: 82.2; F3: 67.9; and F4: 49.5) of platelet count decreased along the aggravation of fibrosis (F0‐F4). The areas under the ROC curve for the platelet count in diagnosis of significant fibrosis stage was 0.70, which had no significant difference with FIB‐4 (0.73) and APRI (0.68) in diagnostic efficacy (P = .428). The areas under the ROC curve of platelet count in diagnosis of early cirrhosis were 0.72, which had no significant difference with FIB‐4 (0.76) and APRI (0.68) (P = .094).

Conclusion

The platelet count, as a simple and non‐invasive index, could evaluate the degree of liver fibrosis in CHB individuals. At the same time, the diagnostic efficiency of platelet count to evaluate the significant liver fibrosis and early cirrhosis is comparable to FIB‐4 and APRI.

Platelet recovery correlates parenchymal volume recovery after liver resection

AIM

Platelet count seems to assess liver function and predict liver regeneration, but factors associated with liver regeneration remain unclear. This study analyzed the relationship between platelet recovery and postresection liver regeneration.

METHODS

Data from 343 candidates from 1245 consecutive patients with liver resection of more than Couinaud's segments were analyzed. Patients were divided into a low-platelet-recovery rate (LPRR) group (lowest 25%) or a control group on the basis of the platelet recovery rate on postoperative day (POD)7. Data were matched before analysis to adjust for operation scale. Trends in liver functional recovery were assessed, and liver volume recovery and remnant ischemic area was calculated using computed tomography volumetry. Factors predicting liver regeneration were analyzed.

RESULTS

In 78 matched-pair patients, the all-complications rate (42.3% vs. 26.9%, P = 0.002) and infectious complications rate (21.8% vs. 9.0%, P = 0.027) were significantly higher in the LPRR group than in controls. Trends in liver functional recovery did not differ significantly, whereas significant differences remained for platelet recovery. Parenchyma volume recovery was delayed in the LPRR group from POD7 (84.5% vs. 78.1, P < 0.01) to POD30 (92.5% vs. 85.6, P < 0.01). Platelet recovery rate on POD7 correlated negatively with ischemic liver volume as evaluated on POD2 by computed tomography (r = 0.691). Postoperative ischemic volume on POD2 (5.41 [1.98-11.21], P < 0.001), infectious complications (3.48 [1.44-7.37], P < 0.001), and multiple resection (1.67 [1.10-4.11], P = 0.011) predicted delayed platelet recovery rate on multivariate analysis.

CONCLUSION

Platelet recovery correlated with liver volume recovery and occurrence of complications. Large ischemic area might negatively impact regeneration after liver resection.

Clinical Implications of Thrombocytopenia for the Cirrhotic Patient

Thrombocytopenia is a frequent complication in patients with cirrhosis. As many as 84% of patients with cirrhosis have thrombocytopenia, and it is an independent variable indicative of advanced disease and poor prognosis. Although there is great concern that it may aggravate bleeding during surgical procedures, there is limited evidence to inform decisions regarding the treatment of cirrhotic patients with thrombocytopenia undergoing invasive procedures. Finally, there is evidence that platelets play a significant role in liver regeneration. In this report, the clinical implications of thrombocytopenia in cirrhotic patients are reviewed. The utility of platelet counts in the prognosis of cirrhosis and relationship to complications of advanced liver disease, including portal hypertension, esophageal varices, and hepatocellular carcinoma. The impact of low platelet counts on bleeding complications during invasive procedures is outlined. Finally, the role of platelets and potential adverse impact in liver regeneration is reviewed.

Fibrotic liver has prompt recovery after ischemia-reperfusion injury

Hepatic ischemia-reperfusion (I/R) is a major complication of liver resection, trauma, and liver transplantation; however, liver repair after I/R in diseased liver has not been studied. The present study sought to determine the manner in which the fibrotic liver repairs itself after I/R. Liver fibrosis was established in mice by CCl4 administration for 6 wk, and then liver I/R was performed to investigate liver injury and subsequent liver repair in fibrotic and control livers. After I/R, fibrotic liver had more injury compared with nonfibrotic, control liver; however, fibrotic liver showed rapid resolution of liver necrosis and reconstruction of liver parenchyma. Marked accumulation of hepatic stellate cells and macrophages were observed specifically in the fibrotic septa in early reparative phase. Fibrotic liver had higher numbers of hepatic stellate cells, macrophages, and hepatic progenitor cells during liver recovery after I/R than did control liver, but hepatocyte proliferation was unchanged. Fibrotic liver also had significantly greater number of phagocytic macrophages than control liver. Clodronate liposome injection into fibrotic mice after I/R caused decreased macrophage accumulation and delay of liver recovery. Conversely, CSF1-Fc injection into normal mice after I/R resulted in increased macrophage accumulation and concomitant decrease in necrotic tissue during liver recovery. In conclusion, fibrotic liver clears necrotic areas and restores normal parenchyma faster than normal liver after I/R. This beneficial response appears to be directly related to the increased numbers of nonparenchymal cells, particularly phagocytic macrophages, in the fibrotic liver.NEW & NOTEWORTHY This study is the first to reveal how diseased liver recovers after ischemia-reperfusion (I/R) injury. Although it was not completely unexpected that fibrotic liver had increased hepatic injury after I/R, a novel finding was that fibrotic liver had accelerated recovery and repair compared with normal liver. Enhanced repair after I/R in fibrotic liver was associated with increased expansion of phagocytic macrophages, hepatic stellate cells, and progenitor cells.

Intercellular crosstalk of hepatic stellate cells in liver fibrosis: New insights into therapy

Liver fibrosis is a dynamic wound-healing process characterized by the net accumulation of extracellular matrix. There is no efficient antifibrotic therapy other than liver transplantation to date. Activated hepatic stellate cells (HSCs) are the major cellular source of matrix-producing myofibroblasts, playing a central role in the initiation and progression of liver fibrosis. Paracrine signals from resident and inflammatory cells such as hepatocytes, liver sinusoidal endothelial cells, hepatic macrophages, natural killer/natural killer T cells, biliary epithelial cells, hepatic progenitor cells, and platelets can directly or indirectly regulate HSC differentiation and activation. Intercellular crosstalk between HSCs and those "responded" cells has been a critical event involved in HSC activation and fibrogenesis. This review summarizes recent advancement regarding intercellular communication between HSCs and other "responded cells" during liver fibrosis and experimental models of intercellular crosstalk systems, and provides novel ideas for potential antifibrotic therapeutic strategy.

Systematic review and meta-analysis of thrombocytopenia as a predictor of post-hepatectomy liver failure

BACKGROUND

We performed a systematic review and meta-analysis to assess whether thrombocytopenia constituted a risk factor for post-hepatectomy liver failure (PHLF).

METHODS

We searched MEDLINE and EMBASE from inception until February the 17th, 2018 for studies reporting cases of PHLF in patients with and without thrombocytopenia (defined as a platelet count below 100 or 150 (G/l)) and/or platelet counts in patients with and without PHLF. Pooled odd ratios for PHLF, as well as mean difference in platelet counts between patients with and without PHLF, were obtained by random effects models. Robustness was tested by subgroups and leave-one out sensitivity analyses. Heterogeneity was assessed using the Q-test and quantified based on I² value.

RESULTS

We included 15 studies representing 3966 patients. Pooled odds ratio for PHLF in thrombocytopenic patients was 3.71 (95% CI: 2.51 to 5.48; I² = 0%). Pooled odds ratio was 5.53 (95% CI: 2.85 to 10.48) when pooling only studies based on preoperative platelet count, and 3.13 (95% CI: 1.75 to 5.58) when pooling studies including only patients without liver cirrhosis. The pooled mean difference in platelet counts between patients with and without PHLF was -21.2 (G/l) (95% CI: -36.1 to 6.4) in disfavor of patients with PHLF. When pooling only patients with various qualities of liver tissue, the pooled mean difference was 0.6 (G/l) (95% CI: -21.1 to 22.2).

CONCLUSION

Preoperative and/or postoperative thrombocytopenia constitute significant risk factors for PHLF in cirrhotic and non-cirrhotic patients.

Platelets in chronic liver disease, from bench to bedside

In the last decade, numerous studies revealed physiologic and pathophysiologic roles of platelets beyond haemostasis, a process to prevent and stop bleeding. These include the activation of the immune system and the promotion of inflammation, infection and cancer. Hence, the emerging view on the role of platelets has shifted - platelets are now seen as alert "sentinels" of the immune compartment, rather than passive bystanders. Herein, we review well-established and newly discovered features of platelets that define their natural role in maintaining blood haemostasis, but also their functional relationship with other cells of the immune system. We focus on recent studies underlining functional involvement of platelets in chronic liver diseases and cancer, as well as the effects of anti-platelet therapy in these contexts. Finally, we illustrate the potential of platelets as possible diagnostic and therapeutic tools in liver disease based on recently developed methodologies.

Platelets and Platelet-Derived Extracellular Vesicles in Liver Physiology and Disease

Beyond their role in hemostasis, platelets are proposed as key mediators of several physiological and pathophysiological processes of the liver, such as liver regeneration, toxic or viral acute liver injury, liver fibrosis, and carcinogenesis. The effects of platelets on the liver involve interactions with sinusoidal endothelial cells and the release of platelet‐contained molecules following platelet activation. Platelets are the major source of circulating extracellular vesicles, which are suggested to play key roles in platelet interactions with endothelial cells in several clinical disorders. In the present review, we discuss the implications of platelet‐derived extracellular vesicles in physiological and pathophysiological processes of the liver.

Intrahepatic fibrin(ogen) deposition drives liver regeneration after partial hepatectomy in mice and humans

Platelets play a pivotal role in stimulating liver regeneration after partial hepatectomy in rodents and humans. Liver regeneration in rodents is delayed when platelets are inhibited. However, the exact mechanisms whereby platelets accumulate and promote liver regeneration remain uncertain. Thrombin-dependent intrahepatic fibrin(ogen) deposition was recently reported after partial hepatectomy (PHx) in mice, but the role of fibrin(ogen) deposits in liver regeneration has not been investigated. We tested the hypothesis that fibrin(ogen) contributes to liver regeneration by promoting intrahepatic platelet accumulation and identified the trigger of rapid intrahepatic coagulation after PHx. PHx in wild-type mice triggered rapid intrahepatic coagulation, evidenced by intrahepatic fibrin(ogen) deposition. Intrahepatic fibrin(ogen) deposition was abolished in mice with liver-specific tissue factor deficiency, pinpointing the trigger of coagulation after PHx. Direct thrombin activation of platelets through protease-activated receptor-4 did not contribute to hepatocyte proliferation after PHx, indicating that thrombin contributes to liver regeneration primarily by driving intrahepatic fibrin(ogen) deposition. Fibrinogen depletion with ancrod reduced both intrahepatic platelet accumulation and hepatocyte proliferation after PHx, indicating that fibrin(ogen) contributes to liver regeneration after PHx by promoting intrahepatic platelet accumulation. Consistent with the protective function of fibrin(ogen) in mice, low postoperative plasma fibrinogen levels were associated with liver dysfunction and mortality in patients undergoing liver resection. Moreover, increased intrahepatic fibrin(ogen) deposition was evident in livers of patients after liver resection but was remarkably absent in patients displaying hepatic dysfunction postresection. The results suggest a novel mechanism whereby coagulation-dependent intrahepatic fibrin(ogen) deposition drives platelet accumulation and liver regeneration after PHx.

Therapeutic implication of platelets in liver regeneration -hopes and hues

Mounting evidence highlights platelet involvement in liver regeneration via interaction with liver cells, growth factors release, and signaling contributions. Existing research suggests a compelling biological rationale for utilizing platelet biology, with the goal of improving liver function and accelerating its regenerative potential. Despite its expanding application in several clinical areas, the contribution of the platelet and its therapeutic implementation in liver regeneration so far has not yet fulfilled the initial high expectations. Areas covered: This review scrutinizes the progress, current updates, and discusses how recent understanding - particularly in the clinical implications of platelet-based therapy - may enable strategies to introduce and harness the therapeutic potential of the platelet during liver regeneration. Expert commentary: Several clinical and translational studies have facilitated a platform for the development of platelet-based therapy to enhance liver regeneration. While some of these therapies are effective to augment liver regeneration, the others have had some detrimental outcomes. The existing evidence represents a challenge for future projects that are focused on directly incorporating platelet-based therapies to induce liver regeneration.

Meta-analysis of the prognostic role of perioperative platelet count in posthepatectomy liver failure and mortality

BACKGROUND

Emerging evidence suggests that the perioperative platelet count (PLT) can predict posthepatectomy liver failure (PHLF). In this systematic review and meta-analysis, the impact of perioperative PLT on PHLF and mortality was evaluated.

METHODS

MEDLINE and Web of Science databases were searched systematically for relevant literature up to January 2018. All studies comparing PHLF or mortality in patients with a low versus high perioperative PLT were included. Study quality was assessed using methodological index for non-randomized studies (MINORS) criteria. Meta-analyses were performed using Mantel-Haenszel tests with a random-effects model, and presented as odds ratios (ORs) with 95 per cent confidence intervals.

RESULTS

Thirteen studies containing 5260 patients were included in the meta-analysis. Two different cut-off values for PLT were used: 150 and 100/nl. Patients with a perioperative PLT below 150/nl had higher PHLF (4 studies, 817 patients; OR 4·79, 95 per cent c.i. 2·89 to 7·94) and mortality (4 studies, 3307 patients; OR 3·78, 1·48 to 9·62) rates than patients with a perioperative PLT of 150/nl or more. Similarly, patients with a PLT below 100/nl had a significantly higher risk of PHLF (4 studies, 949 patients; OR 4·65, 2·60 to 8·31) and higher mortality rates (7 studies, 3487 patients; OR 6·35, 2·99 to 13·47) than patients with a PLT of 100/nl or greater.

CONCLUSION

A low perioperative PLT correlates with higher PHLF and mortality rates after hepatectomy.

Thrombocytopenia after liver transplantation: Should we care?

Transient thrombocytopenia is a common phenomenon after liver transplantation. After liver transplantation (LT), platelet count decreases and reaches a nadir on postoperative days 3-5, with an average reduction in platelet counts of 60%; platelet count recovers to preoperative levels approximately two weeks after LT. The putative mechanisms include haemodilution, decreased platelet production, increased sequestration, medications, infections, thrombosis, or combination of these processes. However, the precise mechanisms remain unclear. The role of platelets in liver transplantation has been highlighted in recent years, and particular attention has been given to their effects beyond hemostasis and thrombosis. Previous studies have demonstrated that perioperative thrombocytopenia causes poor graft regeneration, increases the incidence of postoperative morbidity, and deteriorates the graft and decreases patient survival in both the short and long term after liver transplantation. Platelet therapies to increase perioperative platelet counts, such as thrombopoietin, thrombopoietin receptor agonist, platelet transfusion, splenectomy, and intravenous immunoglobulin treatment might have a potential for improving graft survival, however clinical trials are lacking. Further studies are warranted to detect direct evidence on whether thrombocytopenia is the cause or result of poor-graft function and postoperative complications, and to determine who needs platelet therapies in order to prevent postoperative complications and thus improve post-transplant outcomes.

Prediction of biliary anastomotic stricture after deceased donor liver transplantation: the impact of platelet counts - a retrospective study

Biliary stricture is a common cause of morbidity after liver transplantation (LT). This study aimed to determine the risk factors for post-transplant biliary anastomotic strictures (BAS), focusing on perioperative platelet counts. We enrolled 771 consecutive recipients who underwent ABO-identical/compatible deceased donor LT with duct-to-duct biliary reconstruction from January 2000 to June 2012. BAS was identified in 142 cases. The median time for stricture development was 176 days. Preoperative and postoperative platelet counts within 5 days after LT were significantly lower in patients with BAS than those without BAS. Using cutoff values acquired by the receiver operating characteristic curve analysis, persistent postoperative thrombocytopenia was defined as platelet counts <41 × 1000/μl and <53 × 1000/μl on postoperative day (POD) 3 and POD 5, respectively. Multivariate analysis indicated persistent postoperative thrombocytopenia (OR = 2.38) was the only independent risk factor for BAS. No significant associations were observed in terms of donor and surgical factors. Multivariate analysis demonstrated estimated blood loss (OR = 1.01, per 100 ml) was an independent contributing factor for persistent postoperative thrombocytopenia. We demonstrated low platelet count was associated with progression of post-transplant BAS. Minimizing intraoperative blood loss potentially contributes to maintain post-transplant platelet count, which may reduce incidence of BAS.

Platelets in liver disease, cancer and regeneration

Although viral hepatitis treatments have evolved over the years, the resultant liver cirrhosis still does not completely heal. Platelets contain proteins required for hemostasis, as well as many growth factors required for organ development, tissue regeneration and repair. Thrombocytopenia, which is frequently observed in patients with chronic liver disease (CLD) and cirrhosis, can manifest from decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism; however, the relationship between thrombocytopenia and hepatic pathogenesis, as well as the role of platelets in CLD, is poorly understood. In this paper, experimental evidence of platelets improving liver fibrosis and accelerating liver regeneration is summarized and addressed based on studies conducted in our laboratory and current progress reports from other investigators. In addition, we describe our current perspective based on the results of these studies. Platelets improve liver fibrosis by inactivating hepatic stellate cells, which decreases collagen production. The regenerative effect of platelets in the liver involves a direct effect on hepatocytes, a cooperative effect with liver sinusoidal endothelial cells, and a collaborative effect with Kupffer cells. Based on these observations, we ascertained the direct effect of platelet transfusion on improving several indicators of liver function in patients with CLD and liver cirrhosis. However, unlike the results of our previous clinical study, the smaller incremental changes in liver function in patients with CLD who received eltrombopag for 6 mo were due to patient selection from a heterogeneous population. We highlight the current knowledge concerning the role of platelets in CLD and cancer and anticipate a novel application of platelet-based clinical therapies to treat liver disease.

Relevance of FXR-p62/SQSTM1 pathway for survival and protection of mouse hepatocytes and liver, especially with steatosis

Background

Liver injury and regeneration involve complicated processes and are affected by various physio-pathological conditions. Surgically, severe liver injury after surgical resection often leads to fatal liver failure, especially with some underlying pathological conditions such as steatosis. Therefore, protection from the injury of hepatocytes and liver is a serious concern in various clinical settings.

Methods

We studied the effects of the farnesoid X receptor (FXR) on cell survival and steatosis in mouse hepatocytes (AML12 mouse liver cells) and investigated their molecular mechanisms. We next studied whether or not FXR improves liver injury, regeneration and steatosis in a mouse model of partial hepatectomy (PH) with steatosis.

Results

An FXR-specific agonist, GW4064, induced expressions of the p62/SQSTM1 gene and protein in AML12 mouse liver cells. Because we previously reported p62/SQSTM1 as a key molecule for antioxidation and cell survival in hepatocytes, we next examined the activation of nuclear factor erythroid 2-related factor-2 (Nrf2) and induction of the antioxidant molecules by GW4064. GW4064 activated Nrf2 and subsequently induced antioxidant molecules (Nrf2, catalase, HO-1, and thioredoxin). We also examined expressions of pro-survival and cell protective molecules associated with p62/SQSTM1. Expectedly, GW4064 induced phosphorylation of Akt, expression of the anti-apoptotic molecules (Bcl-xL and Bcl-2), and reduced harmful hepatic molecules (Fas ligand and Fas). GW4064 promoted hepatocyte survival, which was cancelled by p62/SQSTM1 siRNA. These findings suggest the potential relevance of the FXR-p62/SQSTM1 pathway for the survival and protection of hepatocytes. Furthermore, GW4064 induced the expression of small heterodimer partners (SHP) and suppressed liver X receptor (LXR)-induced steatosis in hepatocytes, expecting the in vivo protective effect of FXR on liver injury especially with steatosis. In the hepatectomy model of db/db mice with fatty liver, pre-treatment by GW4064 significantly reduced post-PH liver injury (serum levels of LDH, AST & ALT and histological study) and improved steatosis. The key molecules, p62/SQSTM1, Nrf2 and SHP were upregulated in fatty liver tissue by GW4064 treatment.

Conclusions

The present study is the first to demonstrate the relevance of FXR-p62/SQSTM1 and -SHP in the protection against injury of hepatocytes and post-PH liver, especially with steatosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-016-0568-3) contains supplementary material, which is available to authorized users.

Liver sinusoidal endothelial cells: Physiology and role in liver diseases

Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells representing the interface between blood cells on the one side and hepatocytes and hepatic stellate cells on the other side. LSECs represent a permeable barrier. Indeed, the association of 'fenestrae', absence of diaphragm and lack of basement membrane make them the most permeable endothelial cells of the mammalian body. They also have the highest endocytosis capacity of human cells. In physiological conditions, LSECs regulate hepatic vascular tone contributing to the maintenance of a low portal pressure despite the major changes in hepatic blood flow occurring during digestion. LSECs maintain hepatic stellate cell quiescence, thus inhibiting intrahepatic vasoconstriction and fibrosis development. In pathological conditions, LSECs play a key role in the initiation and progression of chronic liver diseases. Indeed, they become capillarized and lose their protective properties, and they promote angiogenesis and vasoconstriction. LSECs are implicated in liver regeneration following acute liver injury or partial hepatectomy since they renew from LSECs and/or LSEC progenitors, they sense changes in shear stress resulting from surgery, and they interact with platelets and inflammatory cells. LSECs also play a role in hepatocellular carcinoma development and progression, in ageing, and in liver lesions related to inflammation and infection. This review also presents a detailed analysis of the technical aspects relevant for LSEC analysis including the markers these cells express, the available cell lines and the transgenic mouse models. Finally, this review provides an overview of the strategies available for a specific targeting of LSECs.

Platelets: No longer bystanders in liver disease

Growing lines of evidence recognize that platelets play a central role in liver homeostasis and pathobiology. Platelets have important roles at every stage during the continuum of liver injury and healing. These cells contribute to the initiation of liver inflammation by promoting leukocyte recruitment through sinusoidal endothelium. They can activate effector cells, thus amplifying liver damage, and by modifying the hepatic cellular and cytokine milieu drive both hepatoprotective and hepatotoxic processes.

CONCLUSION

In this review we summarize how platelets drive such pleiotropic actions and attempt to reconcile the paradox of platelets being both deleterious and beneficial to liver function; with increasingly novel methods of manipulating platelet function at our disposal, we highlight avenues for future therapeutic intervention in liver disease. (Hepatology 2016;64:1774-1784).

Liver surgery for metastatic colorectal cancer: the surgical oncologist perspective

Neoadjuvant/conversion chemotherapy has emerged as an indispensable tool to achieve resectability of initially unresectable metastatic colorectal cancer and improves oncological outcomes. In parallel, surgical strategy has adopted a more aggressive treatment approach to achieve complete tumor clearance. However, chemotherapy affects liver function and combined with extensive liver resection, morbidity has increased, thereby compromising oncological outcome. There is an imperative need for careful patient selection to optimize patient management. In this review, we discuss available evidence and indications for neoadjuvant treatment in the management of colorectal cancer liver metastases, on preoperative patient selection and identification of high-risk patients, potential treatment strategies to promote postoperative liver regeneration to avoid postoperative morbidity and potentially deleterious side effects of these therapies on tumor growth.

Inhibition of PAR-4 and P2Y12 receptor-mediated platelet activation produces distinct hepatic pathologies in experimental xenobiotic-induced cholestatic liver disease

Emerging evidence supports a protective effect of platelets in experimental cholestatic liver injury and cholangiofibrosis. Coagulation-mediated platelet activation has been shown to inhibit experimental chronic cholestatic liver necrosis and biliary fibrosis. This occurs through thrombin-mediated activation of protease activated receptor-4 (PAR-4) in mice. However, it is not known whether other pathways of platelet activation, such as adenosine diphosphate (ADP)-mediated receptor P2Y12 activation is also protective. We tested the hypothesis that inhibition of P2Y12-mediated platelet activation exacerbates hepatic injury and cholangiofibrosis, and examined the impact of P2Y12 inhibition in both the presence and absence of PAR-4. Treatment of wild-type mice with the P2Y12 receptor antagonist clopidogrel increased biliary hyperplasia and cholangiofibrosis in wild-type mice exposed to the xenobiotic alpha-naphthylisothiocyanate (ANIT) for 4 weeks compared to vehicle-treated mice exposed to ANIT. Interestingly, this effect of clopidogrel occurred without a corresponding increase in hepatocellular necrosis. Whereas biliary hyperplasia and cholangiofibrosis were increased in PAR-4(-/-) mice, clopidogrel treatment failed to further increase these pathologies in PAR-4(-/-) mice. The results indicate that inhibition of receptor P2Y12-mediated platelet activation exacerbates bile duct fibrosis in ANIT-exposed mice, independent of hepatocellular necrosis. Moreover, the lack of an added effect of clopidogrel administration on the exaggerated pathology in ANIT-exposed PAR-4(-/-) mice reinforces the prevailing importance of coagulation-mediated platelet activation in limiting this unique liver pathology.

Novel functions of platelets in the liver

Platelets contain not only proteins needed for hemostasis but also many growth factors that are required for organ development, tissue regeneration, and repair. Thrombocytopenia, which is frequently observed in patients with chronic liver disease (CLD) and cirrhosis, is due to various causes, such as decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism; however, the relationship between thrombocytopenia and hepatic pathogenesis and the role of platelets in CLD are poorly understood. Thus, in this paper, the experimental evidence for platelets improving liver fibrosis and accelerating liver regeneration is summarized and addressed based on studies conducted in our laboratory and current progress reports from other investigators. Platelets improve liver fibrosis by inactivating hepatic stellate cells to decrease collagen production. The level of intracellular cAMP is increased by adenosine through its receptors on hepatic stellate cells, thereby resulting in inactivation of these cells. Adenosine is produced by degradation of adenine nucleotides, which are stored in abundance within the dense granules of platelets. The regenerative effect of platelets in the liver consists of three mechanisms: a direct effect on hepatocytes, a cooperative effect with liver sinusoidal endothelial cells, and a collaborative effect with Kupffer cells. Based on these experiments, a clinical trial suggested that the increase in platelets induced by platelet transfusion improved liver function in patients with CLD in a clinical setting.We highlight the current knowledge concerning the role of platelets in CLD and expect to open a novel avenue for application of these clinical therapies to treat liver disease.

Serial changes of cytokines and growth factors in peripheral circulation after right lobe donor hepatectomy

Cytokines and growth factors have prominent roles in liver regeneration. The aim of this study was to evaluate the biological markers of liver regeneration in healthy donors undergoing right lobe donor hepatectomy for living donor liver transplantation. Twenty-five voluntary liver donors were enrolled. Peripheral blood samples were taken a day before the operation and on postoperative days (PODs) 1, 3, 7, 14, and 42. Levels of hepatocyte growth factor (HGF), interleukin (IL) 6, tumor necrosis factor α (TNF-α), thrombopoietin (TPO), transforming growth factor β1 (TGF-β1), interferon (IFN) α, and IFNγ were monitored. The remnant liver volume (RLV) before surgery and regeneration liver volume (RgV) on POD 14 were calculated on computed tomography (CT). RgV/RLV ratio was correlated with the remnant-liver-volume-to-body-weight ratio (RLVBWR). Inverse correlation was observed between RgV/RLV and RLVBWR (r(2) = 0.61; P < 0.001). There was a significant rise of HGF on POD 1 (P = 0.001), POD 7 (P = 0.049), and POD 14 (P = 0.04). TNF-α was elevated on POD 1 (P = 0.004). The levels of IL 6 (P < 0.001) and TPO (P < 0.001) were higher from POD 1 to POD 42. IFNα was higher on POD 14 (P = 0.003) and POD 42 (P = 0.001). There was a significant fall of IFNγ on POD 1 (P = 0.01) and increase on POD 14 (P = 0.04). The levels of TGF-β1 were higher on POD 14 (P = 0.008) and on POD 42 (P = 0.002). In conclusion, HGF, IL 6, TNF-α, and TPO are involved in the early phase, whereas TGF-β1 and IFN are involved in the termination phase of liver regeneration. Liver regeneration was observed to be higher in donors with low RLVBWR.

A focus on the role of platelets in liver regeneration: Do platelet-endothelial cell interactions initiate the regenerative process?

Platelets are involved in the early phases of liver regeneration. Moreover, platelet transfusion and thrombocytosis were recently shown to enhance hepatocyte proliferation. However, the precise mechanisms remain elusive. This review discusses the latest updates regarding the mechanisms by which platelets stimulate liver regeneration, focusing on their interactions with liver sinusoidal endothelial cells and on their fate within the liver. Following liver injury, platelets are recruited to and trapped within the liver, where they adhere to the endothelium. Subsequent platelet activation results in the release of platelet granules, which stimulate hepatocyte proliferation through activation of the Akt and ERK1/2 signalling pathways. Platelets activate liver sinusoidal endothelial cells, leading to the secretion of growth factors, such as interleukin-6. Finally, liver sinusoidal cells and hepatocytes can also internalize platelets, but the effects of this alternate process on liver regeneration remain to be explored. A better understanding of the mechanisms by which platelets stimulate liver regeneration could lead to improvement in post-operative organ function and allow hepatectomies of a greater extent to be performed.

Effect of omega-3 on hepatic regeneration in adult living donors undergoing hepatic resections for liver transplantation: A randomized controlled trial

BACKGROUND

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) have been shown to improve liver regeneration in experimental models. Aim was to evaluate the effects of ω-3 PUFAs on hepatic regeneration in adult living donors undergoing partial hepatectomy for liver transplantation (LDLT).

METHODS

Forty LDLT donors were categorized into 2 groups: received either intravenous ω-3 PUFA-enriched lipid emulsion 20% infusion 7 mL/kg once a day for 2 days before surgery and postoperative day (POD) 0 (S group) or glucose 5% (C group). Hepatic regeneration was assessed by volume of the liver after 1 month using computed tomography, and serial serum levels of hepatocyte growth factor were measured at POD 1, 3, and 5.

RESULTS

Liver volume after 1 month was significantly larger in the S group than the C group (1286.75 ± 122.781 cm(3) vs 1169.15 ± 128.3, respectively; P = .00). Both the regeneration index and the regeneration percentage were significantly higher in the S group than the C group (P = .02 and P = .00, respectively). Serum levels of hepatocyte growth factor were significantly higher in the S group on POD 1, 3, and 5 than the C group ([in pg/mL] 188.10 ± 74.25 vs 123.30 ± 13.56, P = .00; 127.55 ± 32.40 vs 109.25 ± 8.89, P = .02; and 109.45 ± 21.44 vs 96.70 ± 5.57, P = .01; respectively).

CONCLUSION

Omega-3 polyunsaturated fatty acids effectively promoted liver regeneration and functional recovery following portal hypertension in the setting of LDLT.

Bidirectional role of IL-6 signal in pathogenesis of lung fibrosis

Background

Various signals are known to participate in the pathogenesis of lung fibrosis. Our aim was to determine which signal is predominantly mobilized in the early inflammatory phase and thereafter modulates the development of lung fibrosis.

Methods

Mice received a single dose of 3 mg/kg body weight of bleomycin (BLM) and were sacrificed at designated days post-instillation (dpi). Lung homogenates and sections from mice in the early inflammatory phase were subjected to phospho-protein array analysis and immunofluorescence studies, respectively. Bronchoalveolar lavage fluid (BALF) from mice was subjected to an enzyme-linked immunosorbent assay (EIA) for interleukin (IL)-6 and evaluation of infiltrated cell populations. The effects of endogenous and exogenous IL-6 on the BLM-induced apoptotic signal in A549 cells and type 2 pneumocytes were elucidated. In addition, the effect of IL-6-neutralizing antibody on BLM-induced lung injury was evaluated.

Results

Phospho-protein array revealed that BLM induced phosphorylation of molecules downstream of the IL-6 receptor such as Stat3 and Akt in the lung at 3 dpi. At 3 dpi, immunofluorescence studies showed that signals of phospho-Stat3 and -Akt were localized in type 2 pneumocytes, and that BLM-induced IL-6-like immunoreactivity was predominantly observed in type 2 pneumocytes. Activation of caspases in BLM-treated A549 cells and type 2 pneumocytes was augmented by application of IL-6-neutralizing antibody, a PI3K inhibitor or a Stat3 inhibitor. EIA revealed that BLM-induced IL-6 in BALF was biphasic, with the first increase from 0.5 to 3 dpi followed by the second increase from 8 to 10 dpi. Blockade of the first increase of IL-6 by IL-6-neutralizing antibody enhanced apoptosis of type 2 pneumocytes and neutrophilic infiltration and markedly accelerated fibrosis in the lung. In contrast, blockade of the second increase of IL-6 by IL-6-neutralizing antibody ameliorated lung fibrosis.

Conclusions

The present study demonstrated that IL-6 could play a bidirectional role in the pathogenesis of lung fibrosis. In particular, upregulation of IL-6 at the early inflammatory stage of BLM-injured lung has antifibrotic activity through regulating the cell fate of type 2 pneumocytes in an autocrine/paracrine manner.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0261-z) contains supplementary material, which is available to authorized users.

Immediate Postoperative Low Platelet Counts After Living Donor Liver Transplantation Predict Early Allograft Dysfunction

To investigate whether the platelets can improve liver function by mediating liver regeneration. Using a retrospective cohort with 234 consecutive adult-to-adult living donor liver transplantation recipients, we have discussed the relationship between immediate postoperative platelet count and outcome. Patients have been stratified into Low Platelet Group (106 patients) with platelet ≤68 × 10/L and High Platelet Group (128 patients) with platelet >68 × 10/L.Low Platelet Group has a higher rate of preoperative thrombocytopenia (90.6% vs. 32.8%, P<0.001), higher model for end-stage liver disease score (15 vs. 11, P<0.001), cirrhosis (86.8% vs. 76.6%, P=0.046), hepatorenal syndrome (18.2% vs. 4.0%, P=0.005) and fulminant hepatic failure (26.4% vs. 7.8%, P<0.001). The packed red blood cells transfusion (7.5 vs. 5, P = 0.023) and plasma transfusion (1275 mL vs. 800 mL, P=0.001) are more in patients with low platelet count. Low Platelet Group has a higher early allograft dysfunction (EAD) (22.6% vs. 7.0%, P=0.001) and severe complications (22.6% vs. 10.9%, P = 0.016). The 90-day mortality between the 2 groups is similar. The multivariate analysis has found that postoperative platelet ≤68 × 10/L is an independent risk factor for EAD.Platelet maybe influences the functional status of the liver by promoting graft regeneration after liver transplantation.

Deficiency in thrombopoietin induction after liver surgery is associated with postoperative liver dysfunction

Background and Aims

Thrombopoietin (TPO) has been implicated in the process of liver regeneration and was found to correlate with hepatic function in patients with liver disease. With this investigation we aimed to determine if perioperative TPO levels were associated with postoperative outcome in patients undergoing liver resection.

Methods

Perioperative TPO was analyzed prior to liver resection as well as on the first and fifth postoperative day in 46 colorectal cancer patients with liver metastasis (mCRC) as well as 23 hepatocellular carcinoma patients (HCC). Serum markers of liver function within the first postoperative week were used to define liver dysfunction.

Results

While circulating TPO levels significantly increased one day after liver resection in patients without liver cirrhosis (mCRC) (P < 0.001), patients with underlying liver disease (HCC) failed to significantly induce TPO postoperatively. Accordingly, HCC patients had significantly lower TPO levels on POD1 and 5. Similarly, patients with major resections failed to increase circulating TPO levels. Perioperative dynamics of TPO were found to specifically predict liver dysfunction (AUC: 0.893, P < 0.001) after hepatectomy and remained an independent predictor upon multivariate analysis.

Conclusions

We here demonstrate that perioperative TPO dynamics are associated with postoperative LD. Postoperative TPO levels were found to be lowest in high-risk patients (HCC patients undergoing major resection) but showed an independent predictive value. Thus, a dampened TPO increase after liver resection reflects a poor capacity for hepatic recovery and may help to identify patients who require close monitoring or intervention for potential complications.

p62/SQSTM1 plays a protective role in oxidative injury of steatotic liver in a mouse hepatectomy model

AIMS

Liver injury and regeneration involve complicated processes and are affected by various physio-pathological factors. We investigated the mechanisms of steatosis-associated liver injury and delayed regeneration in a mouse model of partial hepatectomy.

RESULTS

Initial regeneration of the steatotic liver was significantly delayed after hepatectomy. Although hepatocyte proliferation was not significantly suppressed, severe liver injury with oxidative stress (OS) occurred immediately after hepatectomy in the steatotic liver. Fas-ligand (FasL)/Fas expression was upregulated in the steatotic liver, whereas the expression of antioxidant and anti-apoptotic molecules (catalase/MnSOD/Ref-1 and Bcl-2/Bcl-xL/FLIP, respectively) and p62/SQSTM1, a steatosis-associated protein, was downregulated. Interestingly, pro-survival Akt was not activated in response to hepatectomy, although it was sufficiently expressed even before hepatectomy. Suppression of p62/SQSTM1 increased FasL/Fas expression and reduced nuclear factor erythroid 2-related factor-2 (Nrf-2)-dependent antioxidant response elements activity and antioxidant responses in steatotic and nonsteatotic hepatocytes. Exogenously added FasL induced severe cellular OS and necrosis/apoptosis in steatotic hepatocytes, with only the necrosis being inhibited by pretreatment with antioxidants, suggesting that FasL/Fas-induced OS mainly leads to necrosis. Furthermore, p62/SQSTM1 re-expression in the steatotic liver markedly reduced liver injury and improved liver regeneration.

INNOVATION

This study is the first which demonstrates that reduced expression of p62/SQSTM1 plays a crucial role in posthepatectomy acute injury and delayed regeneration of steatotic liver, mainly via redox-dependent mechanisms.

CONCLUSION

In the steatotic liver, reduced expression of p62/SQSTM1 induced FasL/Fas overexpression and suppressed antioxidant genes, mainly through Nrf-2 inactivation, which, along with the hypo-responsiveness of Akt, caused posthepatectomy necrotic/apoptotic liver injury and delayed regeneration, both mainly via a redox-dependent mechanism.

Post-operative depletion of platelet count is associated with anastomotic insufficiency following intrahepatic cholangiojejunostomy: a case-control study from the results of 220 cases of intrahepatic cholangiojejunostomy

Background

Post-operative anastomotic insufficiency following major hepato-biliary surgery has significant impacts on the post-operative course. Recent reports have revealed that platelets play an important role in liver regeneration and wound healing. From these experimental and clinical results on platelet function, we hypothesized that post-operative platelet depletion (to <10 × 10⁴/μL) would be associated with delayed liver regeneration as well as anastomotic insufficiency of intrahepatic cholangiojejunostomy. However, little information is available regarding correlations between platelet count and these complications. The purposes of the present study were, firstly, to evaluate the incidence of anastomotic insufficiency following intrahepatic cholangiojejunostomy and, secondly, to evaluate whether platelet depletion represents a risk factor for anastomotic insufficiency in intrahepatic cholangiojejunostomy.

Methods

Participants in this study comprised 220 consecutive patients who underwent intrahepatic cholangiojejunostomy following hepato-biliary resection for biliary malignancies between September 1998 and December 2010. Anastomotic insufficiency was confirmed by cholangiographic demonstration of leakage from the anastomosis using contrast medium introduced via a biliary drainage tube or prophylactic drain placed during surgery.

Results

Anastomotic insufficiency of the intrahepatic cholangiojejunostomy occurred in 13 of 220 patients (6%). Thirteen of the 220 patients, including one with anastomotic insufficiency, died during the study. Uni- and multivariate analyses both revealed that platelet depletion on post-operative day 1 (<10 × 10⁴/μL) correlated with anastomotic insufficiency.

Conclusion

Post-operative platelet depletion was closely associated with anastomotic insufficiency following intrahepatic cholangiojejunostomy. This correlation has been established, but the underlying mechanisms have not.

Low immediate postoperative platelet count is associated with hepatic insufficiency after hepatectomy

AIM: To investigate the relationship between low immediate postoperative platelet count and perioperative outcome after liver resection in patients with hepatocellular carcinoma (HCC).

METHODS: In a cohort of 565 consecutive hepatitis B-related HCC patients who underwent major liver resection, the characteristics and clinical outcomes after liver resection were compared between patients with immediate postoperative platelet count < 100 × 10⁹/L and patients with platelet count ≥ 100 × 10⁹/L. Risk factors for postoperative hepatic insufficiency were evaluated by multivariate analysis.

RESULTS: Patients with a low immediate postoperative platelet count (< 100 × 10⁹/L) had more grade III-V complications (20.5% vs 12.4%, P = 0.016), and higher rates of postoperative liver failure (6.8% vs 2.6%, P = 0.02), hepatic insufficiency (31.5% vs 21.2%, P < 0.001) and mortality (6.8% vs 0.5%, P < 0.001), compared to patients with a platelet count ≥ 100 × 10⁹/L. The alanine aminotransferase levels on postoperative days 3 and 5, and bilirubin on postoperative days 1, 3 and 5 were higher in patients with immediate postoperative low platelet count. Multivariate analysis revealed that immediate postoperative low platelet count, rather than preoperative low platelet count, was a significant independent risk factor for hepatic insufficiency.

CONCLUSION: A low immediate postoperative platelet count is an independent risk factor for hepatic insufficiency. Platelets can mediate liver regeneration in the cirrhotic liver.

Evidence for serotonin as a relevant inducer of liver regeneration after liver resection in humans

Liver regeneration (LR) involves a complex interplay of growth factors and antagonists. In this context, platelet-derived serotonin (5-HT) has been identified as a critical inducer of LR in mice. Clinical evidence for a role of 5-HT in LR in humans is lacking. Accordingly, serum and plasma 5-HT was monitored perioperatively in 60 patients undergoing liver resection, of which 35 served as exploration and 25 as validation sets. Intraplatelet (IP) levels of 5-HT were calculated by subtraction of plasma 5-HT from serum values. Serum markers of liver function were used to evaluate LR and liver dysfunction (LD). In the exploration setting, IP 5-HT levels significantly decreased after liver resection (P < 0.001) and gradually recovered during the first week. IP 5-HT measured before surgery specifically predicted LD in the subsequent 7 days (area under the curve: 0.721; P = 0.029). Patients suffering from postoperative LD and morbidity were found to have reduced IP 5-HT levels during the entire perioperative period. Furthermore, we validated that reduced preoperative IP 5-HT (<73 ng/mL) was associated with an increased incidence of postoperative LD and morbidity (P = 0.045 and P = 0.021) and were able to demonstrate that IP 5-HT levels were an independent predictor of poor clinical outcome.

CONCLUSIONS

These findings provide evidence that IP 5-HT correlates with LR in humans: Patients with low IP 5-HT before liver resection suffered from delayed hepatic regeneration. Therefore, IP 5-HT levels may prove a helpful clinical marker to predict postoperative LD and clinical outcome before hepatic resection and initiate suitable interventions.

Signal transduction of platelet-induced liver regeneration and decrease of liver fibrosis

Platelets contain three types of granules: alpha granules, dense granules, and lysosomal granules. Each granule contains various growth factors, cytokines, and other physiological substances. Platelets trigger many kinds of biological responses, such as hemostasis, wound healing, and tissue regeneration. This review presents experimental evidence of platelets in accelerating liver regeneration and improving liver fibrosis. The regenerative effect of liver by platelets consists of three mechanisms; i.e., the direct effect on hepatocytes, the cooperative effect with liver sinusoidal endothelial cells, and the collaborative effect with Kupffer cells. Many signal transduction pathways are involved in hepatocyte proliferation. One is activation of Akt and extracellular signal-regulated kinase (ERK)1/2, which are derived from direct stimulation from growth factors in platelets. The other is signal transducer and activator of transcription-3 (STAT3) activation by interleukin (IL)-6 derived from liver sinusoidal endothelial cells and Kupffer cells, which are stimulated by contact with platelets during liver regeneration. Platelets also improve liver fibrosis in rodent models by inactivating hepatic stellate cells to decrease collagen production. The level of intracellular cyclic adenosine monophosphate (cyclic AMP) is increased by adenosine through its receptors on hepatic stellate cells, resulting in inactivation of these cells. Adenosine is produced by the degradation of adenine nucleotides such as adenosine diphosphate (ADP) and adenosine tri-phosphate (ATP), which are stored in abundance within the dense granules of platelets.

Role of platelets in chronic liver disease and acute liver injury

Platelets contain not only hemostatic factors but also many growth factors that play important roles in wound healing and tissue repair. Platelets have already been used for the promotion of tissue regeneration in the clinical setting, such as dental implantation and plastic surgery. Thrombocytopenia, which is frequently found in patients with chronic liver disease and cirrhosis, is due to various causes such as decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism. However, the relationship between thrombocytopenia and hepatic pathogenesis and the role of platelets in chronic liver disease are poorly understood. In acute liver injury, it is reported that platelets are recruited to the liver and contribute to liver damage by promoting the induction of chemotactic factors and the accumulation of leukocytes in the liver, whereas platelets or mediators released by platelets can have a protective effect against liver injury. In this review, we highlight the recent accumulated knowledge concerning the role of platelets in chronic liver disease and acute liver injury.

Platelet therapy: A novel strategy for liver regeneration, anti-fibrosis, and anti-apoptosis

Platelets contain bio-physiological substances, including insulin-like growth factor-1, vascular endothelial growth factor, platelet-derived growth factor, hepatocyte growth factor, serotonin, transforming growth factor-β, adenosine diphosphate, adenosine tri-phosphate, and epidermal growth factor. Platelets have conventionally been considered to exacerbate the inflammatory response and liver injury. Recently, platelets were discovered to have a positive impact on the liver. In this review, we present experimental and clinical evidence indicating that platelets accelerate liver regeneration and have anti-fibrosis and anti-apoptosis activity, and we detail the mechanisms of action. Platelets accelerate liver regeneration by three different mechanisms: (1) a direct effect on hepatocytes, (2) a cooperative effect with liver sinusoidal endothelial cells, and (3) a collaborative effect with Kupffer cells. Platelets exert anti-fibrotic activity by deactivating hepatic stellate cells via the adenosine-cyclic adenosine 5’-monophosphate signaling pathway. Platelets prevent hepatocyte apoptosis by activating the Akt pathway and up-regulating Bcl-xL, which suppresses caspase-3 activation. Platelet therapy with thrombopoietin, thrombopoietin receptor agonists, and platelet transfusion has the advantages of convenience and cost-efficiency over other treatments. We propose that in the future, platelet therapy will play a promising role in the treatment of the various liver disorders that currently challenge the surgical field, such as liver failure after a massive hepatectomy, hepatectomy of a cirrhotic liver, and small grafts in liver transplantation.