Anti-platelet therapy in the prevention of hepatitis B virus-associated hepatocellular carcinoma

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).

High platelet counts increase metastatic risk in huge hepatocellular carcinoma undergoing transarterial chemoembolization

AIM

Accumulating evidence suggests platelets play critical roles in tumor metastasis. Moreover, the role of platelets in metastasis is partially correlated with inflammation. However, evidence regarding the contribution of platelets to hepatocellular carcinoma (HCC) metastasis is lacking. This study investigated the association between platelets and metastatic risk in HCC.

METHODS

We used huge HCC (diameter over 10 cm), a tumor subgroup with a strong inflammatory background, as a model to evaluate the potential predictive role of platelets and platelet-related biomarkers for metastasis in HCC patients undergoing transarterial chemoembolization. A logistic regression model was used to analyze risk factors for metastasis.

RESULTS

Patients with huge HCC (n = 178) were enrolled, and 24.7% (44/178) of patients had remote metastases after treatment. Univariate analyses showed high platelet counts (P = 0.012), pretreatment platelet-to-lymphocyte ratios (pre-PLR) of 100 or more (P = 0.018) and post-PLR of 100 or more (P = 0.013) were potential risk factors for metastasis. Furthermore, multivariate analyses showed high platelet counts (odds ratio, 2.18; 95% confidence interval, 1.074-4.443; P = 0.031) and platelet-related biomarkers were independent risk factors for HCC metastasis. Particularly, the risk of metastasis in patients with high post-PLR values was significantly greater than patients with low post-PLR values. For tumor response and survival, patients with high platelet counts had faster disease progression (P = 0.002) and worse survival (P < 0.0001).

CONCLUSION

High platelet counts increase the extrahepatic metastasis risk of huge HCC undergoing chemoembolization, which supply clinical verification of the association between high platelet counts and HCC metastasis.

Role of hemostatic factors in hepatic injury and disease: animal models de-liver

Chronic liver damage is associated with unique changes in the hemostatic system. Patients with liver disease often show a precariously rebalanced hemostatic system, which is easily tipped towards bleeding or thrombotic complications by otherwise benign stimuli. In addition, some clinical studies have shown that hemostatic system components contribute to the progression of liver disease. There is a strong basic science foundation for clinical studies with this particular focus. Chronic and acute liver disease can be modeled in rodents and large animals with a variety of approaches, which span chronic exposure to toxic xenobiotics, diet-induced obesity, and surgical intervention. These experimental approaches have now provided strong evidence that, in addition to perturbations in hemostasis caused by liver disease, elements of the hemostatic system have powerful effects on the progression of experimental liver toxicity and disease. In this review, we cover the basis of the animal models that are most often utilized to assess the impact of the hemostatic system on liver disease, and highlight the role that coagulation proteases and their targets play in experimental liver toxicity and disease, emphasizing key similarities and differences between models. The need to characterize hemostatic changes in existing animal models and to develop novel animal models recapitulating the coagulopathy of chronic liver disease is highlighted. Finally, we emphasize the continued need to translate knowledge derived from highly applicable animal models to improve our understanding of the reciprocal interaction between liver disease and the hemostatic system in patients.

Preoperative γ-glutamyl transpeptidase to platelet ratio (GPR) is an independent prognostic factor for HBV-related hepatocellular carcinoma after curative hepatic resection

Liver fibrosis and cirrhosis is associated with the prognosis of patients with hepatocellular carcinoma (HCC) after treatment. The γ-glutamyl transpeptidase to platelet ratio (GPR) is reported to predict significant liver fibrosis and cirrhosis. The aim of this study was to investigate the predictive value of preoperative GPR on the recurrence and survival of patients with HCC who underwent curative hepatectomy.A retrospective review of demographics, medical records, and prognosis of patients with hepatitis B virus (HBV)-related HCC was performed. Overall survival (OS) and disease-free survival (DFS) were evaluated using Kaplan-Meier method, and the log-rank test was used to analyze differences in recurrence and survival. Univariate and multivariate analyses were used for significance of prognostic factor.A total of 357 patients with HBV-related HCC were included in this analysis. The preoperative GPR was associated with recurrence and survival rates, independent of HCC progression or tumor marker levels, in a multivariate analysis. OS was higher in patients with a GPR <0.84 versus ≥084 (5-year survival rates 58.6% vs. 38.5%; P < 0.001). DFS was also worse in patients with a GPR ≥0.84 than in those with GPR <0.84 (5-year recurrence rates 42.8% vs. 22.8%; P < 0.001).GPR score of ≥0.84 represents a major risk factor for the poor prognosis for HBV-related HCC after hepatic resection, and GPR served as an independent predictive factor for HBV-related HCC OS.

Modulation of sensitivity and resistance to multikinase inhibitors by microenvironmental platelet factors in HCC

INTRODUCTION

Response of a tumor to chemotherapy or multikinase inhibitor therapy has been traditionally thought to be a reflection of the sum of the characteristics of both the drug and of the tumor cell resistance mechanisms. More recently, there has been a growing awareness of the role of non-tumor factors-both cellular and humoral-in the tumor microenvironment that can increase or decrease the tumor cellular responses to the therapy. This article focuses on platelet factors in clinical HCC and experimental evidence that they provide growth stimulants that can antagonize the growth inhibitory effects of therapy.

AREAS COVERED

Review of the mechanisms of multikinase cancer growth inhibitors and of the role of platelets in providing growth factors that can antagonize their effects.

EXPERT OPINION

These new ideas and data show that the response of a tumor to multikinase inhibitors or chemotherapy may be strongly influenced by microenvironmental factors. Conversely, antagonists to these environmental factors, such as EGFR inhibitors and IGF1-R inhibitors, might be expected to augment the anti-tumor effect of both chemotherapy and multikinase inhibitors.

Advances in therapeutics for chronic hepatitis B

Chronic hepatitis B infection remains a major disease burden globally, and leads to high risk of hepatocellular carcinoma development. Current therapies of nucleot(s)ide analogues and interferon alpha treatment remain limited in their efficacy. Several key findings in the hepatitis B virus (HBV) life cycle have led to the development of novel antiviral drugs to inhibit viral replication and persistence. In addition, recent studies on HBV-specific innate and adaptive immune responses have advanced development of immunotherapy to restore immune mediated virus control in chronic hepatitis B patients. In this review, we discuss potential new therapeutic strategies targeting HBV or the host immune system that might lead to a sustained cure for chronic hepatitis B.

Changing common sense: Anti-platelet/coagulation therapy against cirrhosis

Until recently, anti-platelet/coagulation therapy had not been recommended for patients with cirrhosis. Although venous thrombosis is one of the representative complications of cirrhosis and ischemic disorders associated with atherosclerosis are not infrequent in cirrhotic patients, many clinicians have tended to hesitate to introduce anti-platelet/coagulation therapy to their patients. Undoubtedly, this is due to the increased risk of hemorrhagic diathesis in cirrhotic patients. However, accumulating evidence has revealed the benefits of anti-platelet/coagulation therapy for cirrhotic patients. In addition to the safety of the therapy carried out against cardiovascular diseases in cirrhotic patients, some clinical data have indicated its preventive effect on venous thrombosis. Moreover, the efficacy of anti-platelet/coagulation therapy against cirrhosis itself has been demonstrated both clinically and experimentally. The conceptual basis for application of anti-platelet/coagulation therapy against cirrhosis was constructed through two pathologic studies on intrahepatic thrombosis in cirrhotic livers. It may be better to use thrombopoietin-receptor agonists, which have been tested as a treatment for cirrhosis-related thrombocytopenia, in combination with anti-platelet drugs to reduce the risk of venous thrombosis. During the last decade, the World Journal of Gastroenterology, a sister journal of World Journal of Hepatology, has been one of the main platforms of active discussion of this theme.

Significance of platelet count and platelet-based models for hepatocellular carcinoma recurrence

AIM: To explore the effects of platelet count (PLT) and 11 platelet-based indices on postoperative recurrence of hepatocellular carcinoma (HCC).

METHODS: We retrospectively analyzed 172 HCC patients who were treated by partial hepatectomy. Preoperative data, including laboratory biochemical results, were used to calculate the 11 indices included in the analysis. We performed receiver operating characteristic curve analysis to determine the optimal cut-off values for predicting recurrence. Cumulative rates of HCC recurrence were calculated using Kaplan-Meier survival curves and differences were analyzed by log-rank tests. Multivariate analyses were performed to identify independent predictors of recurrence, early recurrence (within one year after surgery), and late recurrence in HCC. To obtain better prognostic models, PLT-based indices were analyzed separately after being expressed as binary and continuous variables. Two platelet-unrelated, validated HCC prognostic models were included in the analyses as reference indices. Additional analyses were performed after patients were stratified based on hepatitis B virus infection status, cirrhosis, and tumor size to investigate the significance of platelets in different subgroups.

RESULTS: In the study cohort, 44.2% (76/172) of patients experienced HCC recurrence, and 50.6% (87/172) died during a median follow-up time of 46 mo. PLT and five of the 11 platelet-related models were significant predisposing factors for recurrence (P < 0.05). Multivariate analysis indicated that, among the clinical parameters, presence of ascites, PLT ≥ 148 × 10⁹/L, alkaline phosphatase ≥ 116 U/L, and tumor size ≥ 5 cm were independently associated with a higher risk of HCC recurrence (P < 0.05). Independent and significant models included the aspartate aminotransferase/PLT index, fibrosis index based on the four factors, fibro-quotient, aspartate aminotransferase/PLT/γ-glutamyl transpeptidase/alpha-fetoprotein index, and the PLT/age/alkaline phosphatase/alpha-fetoprotein/aspartate aminotransferase index. There were different risk factors between early and late recurrences, and PLT and these indices were more inclined to influence late recurrence. PLT was only predictive of recurrence in non-cirrhotic HCC patients, and was not influenced by tumor size, which was a critical confounder in our study.

CONCLUSION: PLT and PLT-based noninvasive models are effective tools for predicting postoperative recurrence, especially late recurrence. Larger cohorts are needed to validate our findings.

Aspirin and P2Y12 Inhibitors in platelet-mediated activation of neutrophils and monocytes

Platelets are key players in haemostasis and represent a pivotal link between inflammation, immunity and atherogenesis. Depending on the (patho)physiological environment platelets modulate various leukocyte functions via release of inflammatory mediators and direct cell-cell interactions. Elevated levels of circulating platelet-leukocyte aggregates are found in patients suffering from several thrombotic or inflammatory conditions. Platelet-monocyte and platelet-neutrophil interaction can trigger pro- and anti-inflammatory responses and modulate effector functions of all leukocyte subpopulations. These platelet-mediated immune responses have implications for the progression of cardiovascular diseases and also play a crucial role during infections, cancer, transplantations and other inflammatory diseases of several organs. Antiplatelet therapy including the COX inhibitor aspirin and/or ADP receptor P2Y12 inhibitors such as clopidogrel, prasugrel and ticagrelor are the therapy of choice for various cardiovascular complications. Both aspirin and P2Y12 inhibitors attenuate platelet-leukocyte interactions, thereby also modulating immune responses. This may have beneficial effects in some pathological conditions, while it might be detrimental in others. This review aims to summarise the current knowledge on platelet-leukocyte interactions and the impact of aspirin and P2Y12 inhibition on platelet-mediated immune responses and to give an overview on the effects of antiplatelet therapy on platelet-leukocyte interplay in various diseases.

Soluble MICB protein levels and platelet counts during hepatitis B virus infection and response to hepatocellular carcinoma treatment

Background

The human major histocompatibility complex class I polypeptide-related sequence B (MICB) is a protein that modulates the NK and T cell activation through the NKG2D receptor and is related to several diseases including cancer.

Methods

The study investigated the prognostic role of soluble MICB (sMICB) protein in the progression of HBV-related liver diseases and to HBV-related HCC treatment. The sMICB serum levels were measured in 266 chronic HBV-infected Vietnamese patients and in healthy controls, and correlated with clinical and laboratory parameters and with therapeutic interventions for HBV-related HCC.

Results

Significant differences in both clinical and laboratory parameters were observed among the patient groups with different stages of hepatitis. The platelet counts were significantly decreased with disease progression (P < 0.001). The sMICB serum levels were significantly increased in HBV patients compared to healthy controls (P < 0.0001). Among the patients with different stages of hepatitis, asymptomatic individuals (ASYM) revealed higher sMICB serum levels while liver cirrhosis (LC) patients revealed lower sMICB serum levels (P < 0.0001) compared to other patient groups. Notably, the sMICB serum levels were decreased in treated HCC patient group compared to not-treated HCC patient group (P = 0.05). Additionally, the sMICB levels were significantly correlated with platelet counts in ASYM and HCC patients (r = −0.37, P = 0.009; and r = 0.22, P = 0.025, respectively).

Conclusions

Our results demonstrate a potential role of sMICB serum levels and platelet counts during immune response to the HBV infection, liver disease progression and response to the HCC treatment.

Cerebral venous sinus thrombosis may be associated with hepatitis B virus infection: a preliminary finding

OBJECTIVE

To assess the clinical significance of hepatitis B virus (HBV) infection in patients with cerebral venous sinus thrombosis (CVST).

METHODS

Twenty-two patients with CVST confirmed by magnetic resonance venography (MRV) or digital subtraction angiography (DSA) and 743 controls with ischemic stroke confirmed by magnetic resonance imaging (MRI) were analyzed retrospectively.

RESULTS

Among all researches, HBV surface antigen (HBsAg)-positive rate was high. Six of the 22 (27.3%) confirmed cases had HBsAg. However, HBsAg-positive rate in patients with ischemic stroke was only 45 of the 743 cases (6.1%), closed to the average prevalence in China (∼ 8.6%), but much lower than the positive rate in CVST patients (27.3 vs 6.1%, P  =  0.002). Odd ratio (OR) value between HBsAg-positive CVST patients (27.3%) and HBsAg-positive ischemic stroke patients (6.1%) was 5.78. The OR value between HBsAg-positive CVST patients (27.3%) and average prevalence of HBV infection in China (8.6%) was nearly 3.99. It meant that HBV infection might be a risk factor for CVST. However, there existed no statistically significant difference in HBV surface antibody (HBsAb), HBV e antigen (HBeAg), HBV e antibody (HBeAb), and HBV central antibody (HBcAb)-positive rate. The HBV surface antigen (HBsAg)-positive CVST patients did not show worse liver function. Most of them were inactive HBV carriers.

CONCLUSION

Hepatitis B virus infection may be a risk factor for CVST.

Chronic hepatitis B: role of anti-platelet therapy in inflammation control

Platelets play a known role in the maintenance of vascular homeostasis, but these cells are emerging as important cellular mediators of acute and chronic inflammatory diseases. Platelets are key elements in the pathogenesis of acute and chronic liver disease associated with hepatitis B virus (HBV) infection by promoting the accumulation of virus-specific CD8(+) T cells and nonspecific inflammatory cells into the liver parenchyma. This review discusses major platelet functions in immune and inflammatory responses, with an emphasis on recent pre-clinical studies that suggest that the inhibition of platelet activation pathways represent an alternative therapeutic strategy with potential use in the reduction of virus-specific T cell-mediated chronic inflammation, liver fibrosis and hepatocellular carcinoma in patients who are chronically infected with HBV.

Emerging role of dual antiplatelet therapy in the prevention of hepatitis B virus-associated hepatocellular carcinoma

Platelets, the chief effectors of vascular homeostasis, have been identified as important players in the pathogenesis of both acute and chronic liver disease in preclinical models of hepatitis B viral infection. Platelets are thought to promote the accumulation of virus-specific T-cells into the liver parenchyma. Importantly, the inhibition of platelet activation by clinically relevant doses of aspirin and clopidogrel was able to reduce immune-mediated necroinflammatory liver disease, extracellular matrix deposition, and hepatocellular carcinoma development; the same treatment was able to improve overall survival. These results strongly support the design of clinical trials aiming to define the potential of antiplatelet therapy in the prevention of hepatitis B virus-associated hepatocellular carcinoma.

Reproducible complete remission of advanced hepatocellular carcinoma with sorafenib in combination with clopidogrel

We present a 57-year-old Caucasian man with hepatocellular carcinoma (HCC) twice achieving complete remission with reduced dose sorafenib. His initial diagnosis of HCC rapidly improved with sorafenib and he achieved a complete biochemical and radiographic response within 7 months. Remission lasted only 5 months but we noted that the timing of his relapse was immediately after he incidentally discontinued clopidogrel. It was restarted and within 5 months of restarting clopidogrel he once again achieved complete remission. The course of his remission was followed and temporal association of sorafenib remission with use of clopidogrel was observed.

Antagonism of sorafenib and regorafenib actions by platelet factors in hepatocellular carcinoma cell lines

BACKGROUND

Platelets are frequently altered in hepatocellular carcinoma (HCC) patients. Platelet lysates (hPL) can enhance HCC cell growth and decrease apoptosis. The aims were to evaluate whether hPL can modulate the actions of sorafenib or regorafenib, two clinical HCC multikinase antagonists.

METHODS

Several human HCC cell lines were grown in the presence and absence of sorafenib or regorafenib, with or without hPL. Growth was measured by MTT assay, apoptosis was assessed by Annexin V and by western blot, and autophagy and MAPK growth signaling were also measured by western blot, and migration and invasion were measured by standard in vitro assays.

RESULTS

Both sorafenib and regorafenib-mediated inhibition of cell growth, migration and invasion were all antagonized by hPL. Drug-mediated apoptosis and decrease in phospho-ERK levels were both blocked by hPL, which also increased anti-apoptotic phospho-STAT, Bax and Bcl-xL levels. Preliminary data, obtained with epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I), included in hPL, revealed that these factors were able to antagonized sorafenib in a proliferation assay, in particular when used in combination.

CONCLUSIONS

Platelet factors can antagonize sorafenib or regorafenib-mediated growth inhibition and apoptosis in HCC cells. The modulation of platelet activity or numbers has the potential to enhance multikinase drug actions.