Reduced expression of thrombopoietin is involved in thrombocytopenia in human and rat liver cirrhosis

Safety and Efficacy of DPMAS in Patients With Acute-on-Chronic Liver Failure Based on Different Platelet Count Levels

To investigate the effect of different platelet (PLT) counts on the safety and efficacy of the double-plasma molecular absorption system (DPMAS) in patients with acute-on-chronic liver failure (ACLF). A total of 156 patients with ACLF receiving DPMAS were divided into the observed group (40 × 109/L ≤ PLT < 50 × 109/L) and the control group (PLT ≥ 50 × 109/L) according to PLT count level. The safety and efficacy indices of bleeding-related complications, PLT reduction rate, total bilirubin (TBIL) reduction rate, and 28-days survival rate after DPMAS were analyzed and compared between the two groups. The incidence of bleeding complications during and after DPMAS in the observed and control groups (14.3% vs. 14.9%, p = 0.922), the decline rate of PLT immediately and 24 h after treatment (0.13 vs. 0.11/0.05 vs. 0.09, p = 0.256/0.161), and the 28-days survival rate after treatment (76.2% vs. 75.4%, p = 0.923) were not significantly different. The thromboelastogram before DPMAS showed no significant difference in PLT function between the two groups (p > 0.05). Although the TBIL level of the two groups rebounded 24 h after treatment compared with immediately after treatment, it decreased significantly immediately and 24 h after treatment compared with pre-treatment levels (p < 0.05). There was no significant difference in the rate of decline of serum TBIL immediately after treatment and 24 h after treatment between the two groups (0.33 vs. 0.35/0.14 vs. 0.16, p = 0.193 and 0.653, respectively). DPMAS is safe and effective in patients with ACLF with 40 × 109/L ≤ PLT count < 50 × 109/L.

Effectiveness of partial splenic embolization in colorectal cancer patients with chemotherapy-induced thrombocytopenia: results of a single institution retrospective study

Objective

To evaluate the safety and efficacy of partial splenic embolization (PSE) in treating chemotherapy-induced thrombocytopenia (CIT) in patients with colorectal cancer who failed to respond to platelet growth factor therapy.

Methods

56 patients who underwent PSE were retrospectively analyzed. Based on the inclusion and the exclusion criteria, 29 patients were eligible for the study, of whom one underwent twice PSE procedures due to recurrent thrombocytopenia. The clinical characteristics were retrospectively analyzed with respect to efficacy, safety and outcome.

Results

60.0% of patients restarted antineoplastic therapy after PSE. There was a positive correlation between difference value of platelet count and embolization material size (Eta Squared = 0.252, p < 0.05). The correlation between the absolute volume of spleen embolized and postoperative complications was analyzed, with a statistically significant result (p < 0.001). The mean preoperative spleen volume, the preoperative platelet count, postoperative platelet count and difference value of platelet count in the non-cirrhotic group were larger than those in the cirrhotic group (p < 0.001). The mean overall survival was 47.7 ± 7.7 months.

Conclusion

PSE is safe and effective in the treatment of CIT patients with colorectal cancer. The larger the embolized particle, the more platelets grew. The severity of complication was also positively correlated with the absolute volume of spleen embolized. Therefore, large particle embolization materials can be used to improve the efficacy of PSE and reduce complications. For CIT patients with cirrhosis, PSE was less effective in improving platelet count than those without cirrhosis.

Hematological abnormalities in liver cirrhosis

Hematological abnormalities are common in cirrhosis and are associated with various pathophysiological mechanisms. Studies have documented a prevalence of thrombocytopenia, leukopenia, and anemia in patients with compensated cirrhosis of 77.9%, 23.5%, and 21.1%, respectively. These abnormalities carry significant clinical implications, including considerations for invasive procedures, infection risk, bleeding risk, and prognosis. Previously, cirrhosis was believed to predispose patients to bleeding due to alterations observed in classical coagulation tests such as prothrombin time, partial thromboplastin time, international normalized ratio, and thrombocytopenia. However, this understanding has evolved, and cirrhosis patients are now also acknowledged as being at a high risk for thrombotic events. Hemostasis in cirrhosis patients presents a complex phenotype, with procoagulant and anticoagulant abnormalities offsetting each other. This multifactorial phenomenon is inadequately reflected by routine laboratory tests. Thrombotic complications are more prevalent in decompensated cirrhosis and may correlate with disease severity. Bleeding is primarily associated with portal hypertension, endothelial dysfunction, mechanical vessel injury, disseminated intravascular coagulation, endotoxemia, and renal injury. This review comprehensively outlines hematologic index abnormalities, mechanisms of hemostasis, coagulation, and fibrinolysis abnormalities, limitations of laboratory testing, and clinical manifestations of bleeding and thrombosis in patients with liver cirrhosis.

The evolving knowledge on primary hemostasis in patients with cirrhosis: A comprehensive review

Patients with cirrhosis develop complex alterations in primary hemostasis that include both hypocoagulable and hypercoagulable features. This includes thrombocytopenia, multiple alterations of platelet function, and increased plasma levels of von Willebrand factor. Contrary to the historical view that platelet dysfunction in cirrhosis might be responsible for an increased bleeding tendency, the current theory posits a rebalanced hemostasis in patients with cirrhosis. Severe thrombocytopenia is not indicative of the bleeding risk in patients undergoing invasive procedures and does not dictate per se the need for pre-procedural prophylaxis. A more comprehensive and individualized risk assessment should combine hemostatic impairment, the severity of decompensation and systemic inflammation, and the presence of additional factors that may impair platelet function, such as acute kidney injury and bacterial infections. Although there are multiple, complex alterations of platelet function in cirrhosis, their net effect is not yet fully understood. More investigations evaluating the association between alterations of platelet function and bleeding/thrombosis may improve risk stratification in patients with decompensated cirrhosis. Besides hemostasis, the assessment of von Willebrand factor Ag and ADP-induced, whole-blood platelet aggregation normalized by platelet count (VITRO score and PLT ratio) are promising biomarkers to predict the risk of hepatic decompensation and survival in both compensated and decompensated patients. Further investigations into the in vivo interplay between platelets, circulating blood elements, and endothelial cells may help advance our understanding of cirrhotic coagulopathy. Here, we review the complex changes in platelets and primary hemostasis in cirrhosis and their potential clinical implications.

Conversion therapy for advanced hepatocellular carcinoma with vascular invasion: a comprehensive review

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and has a high mortality rate worldwide. The percentage of HCC patients with vascular invasion at the time of initial HCC diagnosis is 10%-40%. According to most guidelines, HCC with vascular invasion is classified as advanced stage, and resection is only suggested for a minority of such patients. Recently, advances in systemic and locoregional treatments for such patients have resulted in amazing response rates. Therefore, a "conversion therapy" strategy including systemic and locoregional treatments is proposed to select patients from an initially unresectable state to eventually undergo R0 resection. Recently, many studies have proven that conversion therapy followed by subsequent surgery is achievable in well-selected advanced HCC patients and can provide prolonged long-term outcomes. Based on published research, this review has summarized the clinical experience and evidence of conversion treatment in HCC patients with vascular invasion.

Dissecting Platelet's Role in Viral Infection: A Double-Edged Effector of the Immune System

Platelets play a major role in the processes of primary hemostasis and pathological inflammation-induced thrombosis. In the mid-2000s, several studies expanded the role of these particular cells, placing them in the "immune continuum" and thus changing the understanding of their function in both innate and adaptive immune responses. Among the many receptors they express on their surface, platelets express Toll-Like Receptors (TLRs), key receptors in the inflammatory cell-cell reaction and in the interaction between innate and adaptive immunity. In response to an infectious stimulus, platelets will become differentially activated. Platelet activation is variable depending on whether platelets are activated by a hemostatic or pathogen stimulus. This review highlights the role that platelets play in platelet modulation count and adaptative immune response during viral infection.

Analysis of predictors after partial splenic embolization for thrombocytopenia with liver cirrhosis

Blood transfusion, splenectomy, and partial splenic embolization (PSE) are generally performed for thrombocytopenia in patients with cirrhosis. Recently, thrombopoietin (TPO) agonists have become available, and investigations of patients who would benefit from them are necessary. Therefore, it is important to understand the fluctuations in cytokine levels associated with PSE. Therefore, fluctuations in platelet-associated immunoglobulin G (PAIgG), interleukin 6 (IL-6), and TPO levels with PSE were analyzed in this study. The study included 110 patients with liver cirrhosis and thrombocytopenia, with the aim of improving platelet counts. Fluctuations in PAIgG, IL-6, and TPO levels were investigated. The average splenic embolization ratio was 58.0% in patients with PSE. The platelet count rose significantly from 6.95 [5.40, 8.60] × 104/mL to 14.05 [10.43, 18.05] × 104/mL (P < .01), IL-6 rose significantly from 3.56 [2.53, 7.33] pg/mL to 18.90 [9.17, 32.95] pg/mL (P < .01), TPO rose significantly from 0.82 [0.52, 1.21] fmol/mL to 1.58 [0.97, 2.26] fmol/mL (P < .01), and PAIgG decreased significantly from 64.20 [38.33, 118.75] ng/107 cells to 37.50 [22.25, 70.00] ng/107 cells (P < .01). On multivariate analysis of factors related to the rate of platelet increase with PSE, primary biliary cholangitis (B = 0.475, P < .01), splenic embolization ratio (B = 0.75, P < .01), IL-6 change ratio (B = 0.019, P < .01), and PAIgG change ratio (B = -0.325, P < .01) were significant. When attempting to improve thrombocytopenia with PSE, adequate splenic embolization needs to be obtained together with improvements in IL-6, PAIgG, and TPO levels. With unsatisfactory improvement in thrombocytopenia, TPO agonist administration was considered.

Thrombocytopenia in chronic liver disease: Physiopathology and new therapeutic strategies before invasive procedures

Chronic liver disease is characterized by several hematological derangements resulting in a complex and barely rebalanced haemostatic environment. Thrombocytopenia is the most common abnormality observed in these patients and recent advances have led to researchers focus the attention on the multifactorial origin of thrombocytopenia and on the key role of thrombopoietin (TPO) in its physiopathology. Severe thrombocytopenia (platelet count < 50000/μL) complicates the management of patients with chronic liver disease by increasing the potential risk of bleeding for invasive procedures, which may be therefore delayed or canceled even if lifesaving. In the very last years, the development of new drugs which exceed the limits of the current standard of care (platelet transfusions, either immediately before or during the procedure) paves the way to a new scenario in the management of this population of patients. Novel agents, such as the TPO-receptor agonists avatrombopag and lusutrombopag, have been developed in order to increase platelet production as an alternative to platelet transfusions. These agents have demonstrated a good profile in terms of efficacy and safety and will hopefully allow reducing limitations and risks associated with platelet transfusion, without any delay in scheduled interventions. Altogether, it is expected that patients with chronic liver disease will be able to face invasive procedures with one more string in their bow.

Predictors of eligibility for reimbursement of antiviral treatment in HBe-Ag negative chronic hepatitis B patients with high ALT levels

Background/Aim: A liver biopsy is required for the reimbursement of antiviral therapy in Hepatitis B e-antigen (HBe-Ag) negative chronic hepatitis B patients. Liver biopsy is an invasive procedure with potential complications, such as bleeding, pain, pneumothorax, and even death. The study aimed to evaluate simple and non-invasive parameters that may help predict histological criteria that would be eligible for antiviral treatment reimbursement. Methods: HBeAg-negative chronic hepatitis B patients with alanine transaminase (ALT) levels > upper normal limit (40 IU/L) and HBV DNA viral load > 2000 IU/ml who underwent liver biopsy were enrolled in this retrospective cohort study. ALT, aspartate aminotransferase (AST), alpha-fetoprotein (AFP) values, hepatitis B virus (HBV) DNA levels, platelet count, and hepato-steatosis grade based on ultrasonography were used to predict the eligibility for antiviral therapy reimbursement. Eligibility for reimbursement of antiviral treatment regarding histological criteria defined by National Social Security Institution is based on the hepatitis activity index (HAI) score ≥ 6 and/or fibrosis score ≥ 2 according to Ishak’s scoring system. Results: One hundred and fifteen patients were included in the study; 79 patients (68.7%) were male. The mean age of patients was 46.51 (11.39). Sixty-two patients (53.9%) had a fibrosis score ≥ 2, and 80 (69.6%) patients had an HAI score ≥ 6. Ninety-two (80%) of the patients fulfilled histological criteria for antiviral treatment reimbursement. Multivariate analysis revealed that age and platelet count were independent predictors of eligibility for antiviral treatment reimbursement. The platelet count cut-off point was 198 x 109 /L for predicting eligibility for antiviral treatment reimbursement. Conclusion: Most patients (92/115, 80%) with high ALT and DNA viral load were eligible for antiviral treatment reimbursement. Platelet count and age may be used as simple non-invasive parameters for predicting the eligibility for antiviral treatment reimbursement in terms of histological findings.

Analysis of Clinical Characteristics and Chronic Factors of Drug-induced Liver Injury in Chronic Hepatitis B Infection: A Retrospective Study

Background: This study investigated clinical characteristics and chronic factors of drug-induced liver injury (DILI) among patients with chronic hepatitis B virus (HBV) infection. Methods: DILI patients were enrolled and divided into a DILI group and an HBV+DILI group. Laboratory indicators were recorded and analyzed. Multivariate logistic regression and the receiver operating characteristic (ROC) curve were used to determine risk factors and the predictive value for chronic DILI. Results: Of all the 114 patients, 87 were in the DILI group and 27 were in the HBV+DILI group. Baseline total bilirubin (TBIL), direct bilirubin (DBIL), and incidence of chronicity were significantly higher in the HBV+DILI group than in the DILI group (P = 0.017, P = 0.037, P = 0.045, respectively). However, platelet (PLT) and prothrombin activity (PTA) were significantly lower in the HBV+DILI group than in the DILI group (P = 0.022, P = 0.013, respectively). HBV infection, baseline aspartate aminotransferase (AST) > 200 U/L, and TBIL > 34.2 μmol/L were predictors of chronic DILI (OR = 4.481 [95% CI, 1.298 - 15.470], P = 0.018; OR = 8.478 [95% CI, 2.079 - 34.566], P = 0.003; OR = 7.358 [95% CI, 2.215 - 24.446], P = 0.001). The area under ROC curve (AUC) of joint diagnosis for chronic DILI was 0.814 (95% CI, 0.704 - 0.925, P < 0.001), which was significantly higher than that of single parameter prediction. Also, the sensitivity, specificity, positive predictive value, and negative predictive value of joint diagnosis were 81.0%, 73.1%, 40.5%, and 94.4%, respectively. Conclusions: HBV infection aggravated liver injury. HBV infection, baseline AST > 200 U/L, and TBIL > 34.2 μmol/L were predictors of chronic DILI, and their joint diagnosis could be used to predict chronic DILI effectively.

Platelet-to-white blood cell ratio: A novel and promising prognostic marker for HBV-associated decompensated cirrhosis

Aim

The present study aimed to investigate associations of the platelet‐to‐white blood cell ratio (PWR)—a novel hematological indicator of inflammatory responses—with 30‐day outcomes in patients with HBV‐associated decompensated cirrhosis (HBV‐DeCi).

Methods

We recruited 131 patients with HBV‐DeCi for this retrospective study and extracted baseline clinical data and laboratory characteristics from medical records. Univariate and multivariate analyses were performed to determine major factors influencing 30‐day mortality. Area under the receiver operating characteristic curve analyses was performed to compare the predictive values of prognostic markers.

Results

During the 30‐day follow‐up period, 15 patients died. The PWR was significantly different between nonsurvivors and survivors. Lower PWR was found to be associated with an increased risk of mortality, and PWR was found to be an independent predictor of mortality in patients with HBV‐DeCi.

Conclusions

Our results demonstrate that low PWR may be a predictor of poor prognosis in patients with HBV‐DeCi, and this factor may be a useful supplement to standard approaches to enable effective management of these patients.

Hemostatic Alterations in Patients With Cirrhosis: From Primary Hemostasis to Fibrinolysis

In the setting of liver cirrhosis (LC), profound hemostatic changes occur, which affect primary hemostasis, coagulation, and fibrinolysis. They involve prohemorrhagic and prothrombotic alterations at each of these steps. Patients with cirrhosis exhibit multifactorial thrombocytopenia and in vitro thrombocytopathy, counterbalanced by increased von Willebrand factor. The resultant shift is difficult to assess, but overall these changes probably result in a rebalanced primary hemostasis. Concerning coagulation, the reduced activity of coagulation factors is counterbalanced by an increase in factor VIII (produced by liver sinusoidal endothelial cells), a decrease of the natural anticoagulants, and complex changes, including changes in circulating microparticles, cell-free DNA, and neutrophil extracellular traps. Overall, these alterations result in a procoagulant state. As for fibrinolysis, increased tissue-type and urokinase-type plasminogen activators, a relatively decreased plasminogen activator inhibitor 1, and decreased levels of thrombin-activatable fibrinolysis inhibitor and α2-antiplasmin are counterbalanced by decreased plasminogen and a decreased fibrin clot permeability. Whether and how these changes shift fibrinolysis remains to be determined. Overall, the current consensus is that in patients with cirrhosis, the hemostasis is shifted toward a procoagulant state. We review the published evidence for the concept of LC as a prothrombotic state, discuss discordant data, and highlight the impact of the underlying cause of LC on the resultant imbalance.

Partial Splenic Artery Embolization in 35 Cancer Patients: Results of a Single Institution Retrospective Study

PURPOSE

To evaluate the safety and efficacy of partial splenic embolization (PSE) in cancer patients with different etiologies of splenomegaly/hypersplenism.

MATERIALS AND METHODS

The medical records of 35 cancer patients who underwent 39 PSE procedures were analyzed. The splenomegaly/hypersplenism was due to chemotherapy (n = 17), portal hypertension (n = 10), or hematologic malignancy (n = 8). After the first 11 PSEs, celiac plexus neurolysis, corticosteroids, and non-steroid anti-inflammatory drugs (NSAIDs) were included in the post-procedural management.

RESULTS

PSE led to 59 ± 16% (mean ± standard deviation) splenic infarcts. The infarct volume per 1 mL 300-500 μm tris-acryl gelatin microspheres was not significantly different between the chemotherapy-induced group (264 ± 89 cm³) and the portal hypertension group (285 ± 139 cm³) but was significantly higher in the hematology group (582 ± 345 cm³). Platelet count increased from 65.7 ± 19.7 k/μl to a peak platelet count of 221 ± 83 k/μl at 2 weeks after PSE. Patients with a follow-up period of more than 1 year had the most recent platelet count of 174 ± 113 k/μl. Platelet count increase was significantly higher in the chemotherapy-induced group than the portal hypertension group. Adding celiac plexus neurolysis, corticosteroids, and NSAIDs to the post-procedural management resulted in a decreased rate of major complications from 73% to 46% and a decrease in the rate of moderate or severe pain from 92% to 20%.

CONCLUSIONS

PSE improved platelet counts in cancer patients despite different etiologies of splenomegaly. The addition of celiac plexus neurolysis, corticosteroids, and NSAIDS to the post-PSE treatment protocol reduced complications. Data from this study could help to predict the amount of 300-500 μm tris-acryl gelatin microspheres required to achieve a planned infarct size.

Thrombocytopenia: A prognostic factor for hepatocellular carcinoma patients with portal vein tumor thrombus after hepatectomy

BACKGROUND AND AIM

Portal vein tumor thrombus (PVTT) predicts a poor prognosis in hepatocellular carcinoma (HCC) patients. Platelets (PLTs) play an important role in HCC progression and metastasis. However, the relationship between PLTs and PVTT remains unclear. This study aimed to evaluate the value of PLT counts in the prognosis of HCC patients with PVTT after hepatectomy.

METHODS

From January 2002 to December 2012, 694 HCC patients with PVTT after hepatectomy were evaluated. The patients were divided into the thrombocytopenia group (PLT < 100 × 10⁹ /L), the normal group, and the thrombocytosis group (PLT > 300 × 10⁹ /L) based on the preoperative PLT level. A propensity score matching (PSM) analysis was used.

RESULTS

Before the PSM, PVTT patients with thrombocytopenia exhibited longer recurrence-free survival (RFS) and overall survival (OS) compared with those with normal PLT counts (both P < 0.001) or thrombocytosis (P = 0.008 and P = 0.046). For the thrombocytopenia group and the normal group, the 1-, 2-, and 3-year RFS values were 30.0%, 17.6%, and 15.7% and were 10.8%, 6.6%, and 5.8% (P < 0.001), respectively; the 1-, 2-, and 3-year OS values were 61.9%, 37.9%, and 31.2% and were 38.3%, 23.3%, and 16.0% (P < 0.001), respectively. After the PSM, the median survival time was 16.6 versus 8.6 months (P < 0.002) in the two groups. A subgroup analysis revealed that thrombocytopenia is associated with improved OS in those with type I PVTT (P = 0.021) or type II PVTT (P = 0.029).

CONCLUSION

According to the PSM, preoperative thrombocytopenia predicts an increased RFS and OS in HCC patients with PVTT after hepatectomy.

Thrombocytopenia in chronic liver disease

Thrombocytopenia is a common haematological disorder in patients with chronic liver disease. It is multifactorial and severity of liver disease is the most influential factor. As a result of the increased risk of bleeding, thrombocytopenia may impact upon medical procedures, such as surgery or liver biopsy. The pathophysiology of thrombocytopenia in chronic liver disease has long been associated with the hypothesis of hypersplenism, where portal hypertension causes pooling and sequestration of all corpuscular elements of the blood, predominantly thrombocytes, in the enlarged and congested spleen. Other mechanisms of importance include bone marrow suppression by toxic substances, such as alcohol or viral infection, and immunological removal of platelets from the circulation. However, insufficient platelet recovery after relief of portal hypertension by shunt procedures or minor and transient recovery after splenic artery embolization have caused many to question the importance and relative contribution of this mechanism to thrombocytopenia. The discovery of the cytokine thrombopoietin has led to the elucidation of a central mechanism. Thrombopoietin is predominantly produced by the liver and is reduced when liver cell mass is severely damaged. This leads to reduced thrombopoiesis in the bone marrow and consequently to thrombocytopenia in the peripheral blood of patients with advanced-stage liver disease. Restoration of adequate thrombopoietin production post-liver transplantation leads to prompt restoration of platelet production. A number of new treatments that substitute thrombopoietin activity are available or in development.

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.

JOURNAL CLUB: Four-Dimensional Flow MRI-Based Splenic Flow Index for Predicting Cirrhosis-Associated Hypersplenism

OBJECTIVE

The objective of this study is to evaluate the ability of spleen volume, blood flow, and an index incorporating multiple measures to predict cirrhosis-associated hypersplenism.

MATERIALS AND METHODS

A total of 39 patients (14 women and 25 men; mean [± SD] age, 52 ± 10 years) with cirrhosis and sequelae of portal hypertension underwent 4D flow MRI and anatomic 3-T MRI performed before and after contrast administration. Unenhanced 4D flow MRI was used to assess abdominal hemodynamics, and splenic volumes were measured on T1-weighted gradient-recalled echo MRI. Relationships among demographic characteristics, blood component counts, splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were assessed in 29 consecutive patients (i.e., the derivation group), to develop a splenic flow index. This index was assessed along with splenic volume and blood flow alone in 10 additional consecutive patients (i.e., the validation group) via ROC curve analysis, to identify platelet counts of less than 50 × 10³ cells/μL, leukocyte counts of less than 3.0 × 10³ cells/μL, or both.

RESULTS

In the derivation cohort (platelet count, 129 ± 76 × 10³ cells/μL), splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were inversely correlated with platelet counts (ρ = -0.68, -0.68, -0.56, and -0.36, respectively; p < 0.05). Adding splenic volume to arterial flow and the product of venous flow and the percentage of shunted portal flow indexed to the body surface area yielded superior correlations with platelet counts, leukocyte counts, and the degree of severity of hypersplenism (ρ = -0.75, -0.48, and -0.75, respectively; p ≤ 0.001) and predicted severe hypersplenism (sensitivity, 100%; specificity, 100%) in the validation cohort (platelet count, 93 ± 71 × 10³ cells/μL).

CONCLUSION

A splenic flow index that incorporates both splenic volume and blood flow is a better indicator of hypersplenism than is splenic volume alone.

The Plant Hormone Abscisic Acid Is a Prosurvival Factor in Human and Murine Megakaryocytes

Abscisic acid (ABA) is a phytohormone involved in pivotal physiological functions in higher plants. Recently, ABA has been proven to be also secreted and active in mammals, where it stimulates the activity of innate immune cells, mesenchymal and hematopoietic stem cells, and insulin-releasing pancreatic β cells through a signaling pathway involving the second messenger cyclic ADP-ribose (cADPR). In addition to behaving like an animal hormone, ABA also holds promise as a nutraceutical plant-derived compound in humans. Many biological functions of ABA in mammals are mediated by its binding to the LANCL-2 receptor protein. A putative binding of ABA to GRP78, a key regulator of endoplasmic reticulum stress, has also been proposed. Here we investigated the role of exogenous ABA in modulating thrombopoiesis, the process of platelet generation. Our results demonstrate that expression of both LANCL-2 and GRP78 is up-regulated during hematopoietic stem cell differentiation into mature megakaryocytes (Mks). Functional ABA receptors exist in mature Mks because ABA induces an intracellular Ca²⁺ increase ([Ca²⁺] _i ) through PKA activation and subsequent cADPR generation. In vitro exposure of human or murine hematopoietic progenitor cells to 10 μm ABA does not increase recombinant thrombopoietin (rTpo)-dependent Mk differentiation or platelet release. However, under conditions of cell stress induced by rTpo and serum deprivation, ABA stimulates, in a PKA- and cADPR-dependent fashion, the mitogen-activated kinase ERK 1/2, resulting in the modulation of lymphoma 2 (Bcl-2) family members, increased Mk survival, and higher rates of platelet production. In conclusion, we demonstrate that ABA is a prosurvival factor for Mks in a Tpo-independent manner.

Branched-chain amino acid-enriched nutrient increases blood platelet count in patients after endoscopic injection sclerotherapy

AIM

Protein and energy malnutrition is a severe problem for patients with liver cirrhosis (LC) and fasting often induces starvation which is a vitally important outcome. Dietary restriction is essential for endoscopic injection sclerotherapy (EIS) in patients with risky esophageal varices, thereby creating the possible exacerbation of nutritional state and inducing liver dysfunction. Whether EIS induces nutritional deficiency in LC patients and the effects of branched-chain amino acid (BCAA)-enriched nutrient are prospectively investigated.

METHODS

A total of 61 LC patients were randomly divided into an EIS monotherapy group (non-BCAA group, n = 31) and an EIS combined with BCAA therapy group (n = 30). Platelet count, blood chemistry and somatometry values were prospectively measured at five time points.

RESULTS

The platelet counts before treatment were at the same level in both groups (P = 0.72). Three months after treatment, the counts decreased in the non-BCAA group; however, they increased in the BCAA group (P = 0.019). Body mass index, triceps skin fold thickness and arm muscle circumference significantly decreased in both groups. The BCAA and tyrosine ratio value increased only in the BCAA group (P < 0.01). The skeletal muscle volume measured by InBody720 significantly decreased in the non-BCAA group (P < 0.001).

CONCLUSION

EIS induced protein-energy malnutrition, however, skeletal muscle volume was maintained by taking BCAA. Administration of BCAA had some effect in maintaining the nutritional state, and may improve the platelet count. Taking a greater amount of nutrients and shorter dietary restriction period or hospitalization was desirable.

Association of Nonalcoholic Fatty Liver Disease and Venous Thromboembolism in Women With Endometrial Cancer

OBJECTIVE

Recent studies have demonstrated that surgical menopause results in a significantly increased risk of nonalcoholic fatty liver disease (NAFLD) in women with endometrial cancer. In addition, venous thromboembolism (VTE) is known to be one of the major prognostic factors for decreased survival in endometrial cancer. Given the fact that coagulation factors are produced in the liver, the correlation between NAFLD and VTE was examined in endometrial cancer.

METHODS

A retrospective study was conducted to examine patients with endometrial cancer who underwent surgical staging including oophorectomy between 2000 and 2013 (n = 714). Cumulative risk of VTE was examined based on the NAFLD status. A Cox proportional hazard regression model was used to determine the independent risk predictors of VTE.

RESULTS

Venous thromboembolism and NAFLD were seen in 57 (8.0%) and 181 (25.4%) cases, respectively. Two-year cumulative risks of VTE and NAFLD were 7.9% and 19.3%, respectively. In univariate analysis, VTE was significantly associated with decreased disease-free survival (2-year rate, 43.6% vs 91.4%, P < .001) and overall survival (65.8% vs 96.8%, P < .001), whereas NAFLD was associated with decreased risk of VTE (1.7% vs 10.4%, P < .001). In multivariate analysis controlling for clinicopathological factors, NAFLD remained an independent predictor of decreased risk of VTE (hazard ratio [HR]: 0.24, 95% confidence interval [CI]: 0.07-0.79, P = .02). Thrombocytosis (HR: 2.30, 95% CI: 1.22-4.35, P = .01), cancer antigen 125 ≥ 35 (HR: 3.81, 95% CI: 1.78-8.17, P < .001), and recurrent disease (HR: 4.57, 95% CI: 1.97-10.6, P < .001) remained as independent predictors of increased risk of VTE.

CONCLUSION

Our results suggest that NAFLD may be associated with decreased VTE risk in women with endometrial cancer.

Telaprevir-based triple therapy following partial splenic arterial embolization for chronic hepatitis C with thrombocytopenia can reduce carcinogenesis and improve hepatic function reserve

Thrombocytopenia in patients with chronic hepatitis C negatively impacts interferon (IFN)-based treatment. The aim of this study was to evaluate the efficacy and safety of telaprevir (TVR)-based triple therapy including IFN for patients who have undergone partial splenic arterial embolization (PSE). Ten patients with thrombocytopenia who were infected with hepatitis C virus (HCV) genotype 1b received 12 weeks of TVR in combination with 24 weeks of pegylated interferon (PEG-IFN)α2b and ribavirin following PSE. A sustained virological response (SVR) was seen in 9 of the 10 patients who could be assessed. Early relapse was seen in 1 patient who had the IL-28B minor allele and a null response to pretreatment. The α-fetoprotein levels of the patients decreased from 17.94±7.30 ng/ml prior to PSE to 4.33±2.41 ng/ml at 6 months after triple therapy (P=0.08). Furthermore, serum albumin levels improved significantly from 3.68±0.49 g/dl pre-PSE to 4.13±0.34 g/dl at 12 months after triple therapy (P=0.043). PSE contributed to the treatment success of triple therapy, particularly for patients who were either treatment-naïve, had a history of relapse or the IL28B major allele. This strategy can reduce carcinogenesis and improve hepatic function reserve.

Management of thrombocytopenia in advanced liver disease

Thrombocytopenia (defined as a platelet count <150×10(9)) is a well-known complication in patients with liver cirrhosis and has been observed in 76% to 85% of patients. Significant thrombocytopenia (platelet count <50×10(9) to 75×10(9)) occurs in approximately 13% of patients with cirrhosis. Thrombocytopenia can negatively impact the care of patients with severe liver disease by potentially interfering with diagnostic and therapeutic procedures. Multiple factors can contribute to the development of thrombocytopenia including splenic platelet sequestration, immunological processes, bone marrow suppression by chronic viral infection, and reduced levels or activity of the hematopoietic growth factor thrombopoietin. The present review focuses on the etiologies and management options for severe thrombocytopenia in the setting of advanced liver disease.

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.

The significance of platelet consumption in the development of thrombocytopenia in patients with cirrhosis

INTRODUCTION

Thrombocytopenia in cirrhosis is mainly explained by accelerated platelet destruction/sequestration because of hypersplenism or by decreased thrombopoietin levels. Excessive platelet consumption because of cirrhosis-related hypercoagulability has also been assumed to be an etiopathologic factor in thrombocytopenia. To clarify whether excessive platelet consumption (eg, venous thrombosis and disseminated intravascular coagulation) contributes to thrombocytopenia in cirrhosis, the following autopsy-based study was performed.

METHODS

Ninety-nine autopsies of chronic liver disease (80 cirrhosis and 19 noncirrhosis) were examined retrospectively. Platelet count, weight of spleen and thrombotic complications were checked in autopsy protocols. Megakaryocytes in bone marrow were counted under high-power microscopic view. Univariate and multivariate analyses were performed to evaluate significances of these factors in thrombocytopenia.

RESULTS

The platelet count was significantly lower in the cirrhosis cases (88 ± 51 × 10/L) than in the noncirrhosis cases (150 ± 120 × 10/L). The megakaryocyte count was also lower in the cirrhosis cases (1.5 ± 0.6 per high-power field) than in the noncirrhosis cases (1.9 ± 0.5 per high-power field). The weight of the spleen was greater in the cirrhosis cases (264 ± 179 g) than in the noncirrhosis cases (142 ± 82 g). Thrombotic complications had been recorded in 29 cases, whose platelet count (70 ± 41 × 10/L) was lower than that of those without these complications (113 ± 80 × 10/L). Multivariate analysis revealed that these 3 factors (megakaryocyte count, weight of spleen, and thrombotic complications) were independently correlated with the platelet count.

CONCLUSIONS

These results suggest that the imbalance of platelet production-destruction/sequestration-consumption contributes to thrombocytopenia in cirrhosis. Excessive platelet consumption cannot be ignored to explain this complex condition, especially in patients with major thrombotic events.

Causes of thrombocytopenia in chronic hepatitis C viral infection

We retrospectively studied 89 patients with chronic hepatitis C virus (HCV) infection, including 50 chronic hepatitis (CH) cases, 18 liver cirrhosis (LC) cases, and 21 LC with hepatocellular carcinoma (LC + HCC) cases, with regard to various factors related with thrombocytopenia. The platelet count decreased with the stage advancement of liver diseases. Multiple regression analysis revealed that splenomegaly and von Willebrand factor (vWF) were explanatory variables that correlated with thrombocytopenia. Splenomegaly appears to be the most responsible factor, although there are a considerable number of thrombocytopenic cases without splenomegaly, suggesting other factors may also be responsible. The vWF level is inversely correlated with the platelet count. Soluble thrombomodulin, a marker of endothelial dysfunction, increases with the advancement of liver fibrosis. It is positively correlated with vWF and inversely with the platelet count. Our present results imply that vascular endothelial dysfunction is also involved in thrombocytopenia during chronic HCV infection.

Single administration of thrombopoietin prevents progression of liver fibrosis and promotes liver regeneration after partial hepatectomy in cirrhotic rats

OBJECTIVE

To evaluate the effect of thrombopoietin on liver regeneration after hepatectomy and antifibrosis under conditions of liver cirrhosis in rats.

SUMMARY BACKGROUND DATA

We revealed that platelets induced by thrombopoietin administration promote liver regeneration after hepatectomy in the normal liver.

METHODS

Seventy percent hepatectomy was carried out in rats, which were subsequently divided into 4 groups: (1) normal group without any treatment, (2) liver cirrhosis (LC) group, (3) combined thrombopoietin and liver cirrhosis (LC+TPO) group, and (4) combined thrombopoietin, antiplatelet serum and liver cirrhosis (LC+TPO+APS) group. Growth kinetics in the liver regeneration and growth factors were analyzed. Liver fibrotic area and activation of hepatic stellate cells were also investigated.

RESULTS

In LC group, liver regeneration was significantly delayed compared with normal group 24 hours after hepatectomy. On the other hand, liver regeneration of LC+TPO group increased significantly compared with LC group, to a level that was the same as that recorded in normal group. In LC group, liver fibrotic area before hepatectomy was significantly higher compared with the normal group. Liver fibrosis of LC+TPO group was significantly reduced compared with LC group. The antifibrotic and liver regeneration promoting effects of LC+TPO group were inhibited by antiplatelet serum in LC+TPO+APS group.

CONCLUSION

The administration of thrombopoietin reduces liver fibrosis and stimulates regeneration after hepatectomy through increment and accumulation of platelets in the cirrhotic liver. This could be a potentially useful treatment for liver cirrhosis.

Thrombopoietin is a growth factor for rat hepatic progenitors

OBJECTIVE

The liver is the primary site of hematopoiesis during fetal development; it has been shown that thrombopoietin (TPO) produced by the liver during fetal development is a major regulator of megakaryocytopoiesis. As maximum liver growth and hematopoiesis occur simultaneously, we hypothesized that TPO may act as a growth factor for hepatic progenitors. Therefore, the influence of TPO on the proliferation of fetal hepatic progenitors in vitro compared with that of adult hepatocytes was analyzed. The expression of the TPO receptor, c-mpl, was investigated in fetal and adult liver.

METHODS

Cell proliferation was measured by bromodeoxyuridine incorporation and total cell counts. TPO and c-mpl gene expression was investigated by reverse transcription polymerase chain reaction. The cell surface expression of c-mpl was analyzed in fetal and adult human liver by immunohistochemistry.

RESULTS

Hepatic progenitors of fetal and adult liver but not hepatocytes expressed the TPO receptor, c-mpl, on the cell surface. Fetal hepatic progenitors expressed mRNA for TPO and its receptor. TPO stimulated cell proliferation and increased cell numbers of cultured rat fetal hepatic progenitors but not adult hepatocytes.

CONCLUSION

We conclude that TPO acts in addition to its known role in megakaryocytopoiesis as a growth factor for hepatic progenitors but not hepatocytes in vitro; thus, TPO represents a growth factor for hepatic progenitors during fetal liver development.

Predictive factors for platelet increase after partial splenic embolization in liver cirrhosis patients

BACKGROUND AND AIM

Partial splenic embolization (PSE) is often performed for improving thrombocytopenia in cirrhotic patients. We investigated the largely unclear predictive factors for platelet increase at both 1 month and 1 year after PSE.

METHODS

Aimed at increasing the platelet count, PSE was performed in 42 cirrhotic patients with thrombocytopenia (platelets < 80 x 10(4)/mL) caused by hypersplenism. The clinical data were analyzed to clarify the predictive factors for platelet increase at 1 month (n = 42) and 1 year (n = 38) after PSE.

RESULTS

The mean splenic infarction ratio was 76.7% +/- 11.2%. The platelet count increased to 259% +/- 112% and 228% +/- 75% of the pretreatment values at 1 month and at 1 year after PSE, respectively. Stepwise multiple linear regression analysis showed that the infarcted splenic volume had a positive independent association with the increase in platelet count at both 1 month (P = 0.00004) and 1 year (P = 0.005) after PSE (increase in platelet count (x10(4)/mL): at 1 month = 0.752 + 0.018 x infarcted splenic volume (mL), R(2) = 0.344; at 1 year = 2.19 + 0.01 x infarcted splenic volume (mL), R(2) = 0.203). Receiver operating characteristic analysis yielded a cut-off value of 388 mL of infarcted splenic volume for achieving an increase of 5.0-8.0 x 10(4)/mL in platelet count at 1 year.

CONCLUSIONS

PSE can reduce the platelet pool and induce an increase in platelet count. This increase is greatly dependent on the infarcted splenic volume.

Liver fibrosis is associated with decreased peripheral platelet count in patients with chronic hepatitis B and C

Thrombocytopenia is a common complication of chronic liver diseases, but its pathogenesis is not clear. Although generally attributed to hypersplenism, other factors should also be considered. We investigated the relationship between the peripheral platelet count and the degree of fibrosis in patients with chronic viral hepatitis. In an effort to avoid the effects of hypersplenism, we excluded patients with splenomegaly and/or bi- or pan-cytopenia. Seven hundred eighty-four patients (265 chronic viral hepatitis C and 519 chronic viral hepatitis B) were included in the study. Univariate analysis showed that the peripheral platelet count had a negative correlation with fibrosis score, necroinflammatory activity, and age in both groups. In multivariate analysis, the peripheral platelet count had a similar correlation with the fibrosis score and age, but not with necroinflammatory activity, in both groups. The peripheral platelet count decreased more significantly in females with chronic hepatitis C but not in the chronic hepatitis B group. In conclusion, a decrease in peripheral platelet count may be a sign of an increase in the degree of fibrosis during the course of chronic viral hepatitis B and C and factors other than hypersplenism may play a role in this decrease in the peripheral platelet count.

Hepatitis C virus interacts with human platelet glycoprotein VI

Hepatitis C virus (HCV) interacts with human platelets in vivo as a potential transport of infectious virions to the target liver. The binding of native viral particles with the platelet membrane glycoprotein VI (GPVI) was analysed. A consistent interaction between HCV from plasma or after purification by two different methods and the recombinant extracellular immunoglobulin (Ig)-like domains of human GPVI (hD1D2) was observed with two independent experimental approaches: pull-down and ELISA assays. Between 2 and 7 % of HCV particles were specifically bound to hD1D2. The binding was inhibited by an anti-hD1D2 in a dose-dependent manner. Human D1D2 interaction with HCV was significantly higher than the murine D1D2, supporting the specificity of the interaction and to the single human domains (D1 and D2), suggesting that both Ig-like domains of the molecule are required for efficient binding. GPVI may be a platelet surface ligand for HCV playing a role in viral transport and persistence.

Hemostatic defects in end stage liver disease

End stage liver disease results in a complex and variably severe failure of hemostasis that predisposes to abnormal bleeding. The diverse spectrum of hemostatic defects includes impaired synthesis of clotting factors, excessive fibrinolysis, disseminated intravascular coagulation, thrombocytopenia, and platelet dysfunction. Hemostasis screening tests are used to assess disease severity and monitor the response to therapy. Correction of hemostatic defects is required in patients who are actively bleeding or require invasive procedures. Fresh frozen plasma, cryoprecipitate, and platelet transfusion remain the mainstays of therapy until larger trials confirm the safety and efficacy of recombinant factor VIIa in this population.

Role of elevated platelet-associated immunoglobulin G and hypersplenism in thrombocytopenia of chronic liver diseases

BACKGROUND AND AIM

Thrombocytopenia typically worsens with the progression of liver disease and can become a major clinical complication. Several mechanisms that contribute to thrombocytopenia have been proposed, including hypersplenism accompanied by increased platelet sequestration, platelet destruction mediated by platelet-associated immunoglobulins (PAIgG), and diminished platelet production stimulated by thrombopoietin (TPO). The purpose of the present study was to evaluate the role of each of these mechanisms in patients with liver disease-associated thrombocytopenia.

METHODS

Twenty-nine patients with liver cirrhosis (LC), 20 of whom were hepatitis C virus (HCV)-seropositive, 29 chronic hepatitis (CH) patients, 24 of whom were HCV-seropositive, and 16 control patients without liver or hematopoetic disease were enrolled in this study. Serum TPO levels, PAIgG, and liver-spleen volumes were determined and correlation analyses were performed.

RESULTS

No differences in serum TPO levels were observed among the three groups. The PAIgG levels were significantly elevated in CH and LC patients (mean +/- SD: 56.5 +/- 42.3 and 144.6 +/- 113.6 ng/107 cells, respectively) compared with the controls (18.9 +/- 2.5 ng/107 cells, P < 0.001 for both). Spleen volume was significantly higher only in LC (428 +/- 239) compared with CH (141 +/- 55) and control (104 +/- 50 cm3) (P < 0.001), while liver volume was not significantly different between the three groups. Correlation analyses demonstrated a significant negative correlation between platelet count with PAIgG (r = - 0.517, P < 0.001) and spleen volume (r = - 0.531, P < 0.001), and no relationship between platelet count and serum TPO level (r = 0.076).

CONCLUSIONS

Serum TPO level may not be directly associated with thrombocytopenia in patients with chronic hepatitis and liver cirrhosis. In contrast, spleen volume and PAIgG are associated with thrombocytopenia in such patients, suggesting that hypersplenism and immune-mediated processes are predominant thrombocytopenic mechanisms.

Thrombopoietin in acute liver failure

Thrombopoietin (TPO) is the primary regulator of platelet production. TPO is produced in the liver and levels are low in patients with cirrhosis. Because thrombocytopenia is common in patients with acute liver failure (ALF), we measured TPO concentrations (normal TPO range, 31 to 136 pg/mL) in 51 patients with ALF to determine if low levels were associated with thrombocytopenia. TPO levels from hospital day 2 were elevated in 43% of patients, normal in 47%, and decreased in 10% of patients. Levels were higher in acetaminophen-induced than in non-acetaminophen-induced ALF, 160 (12 to 549) pg/mL versus 73 (18 to 563) pg/mL, respectively, P =.031. TPO levels did not correlate with platelet count and were not related with survival or infection. We analyzed daily TPO levels for the first week of hospitalization in 12 patients with acetaminophen-induced ALF and observed a gradual increase from a median admission level of 50 (5 to 339) pg/mL to a median peak level of 406 (125 to 1,081) pg/mL occurring on day 5 (3 to 6). Platelets were reduced in 11 of the 12 patients with a nadir platelet count of 52 (19 to 156) x 10(9) cells/L occurring on day 5.5 (1 to 6). The peak TPO level did not correlate with the nadir platelet count (P =.43). In conclusion, the normal inverse relationship between platelet count and TPO levels was not observed in ALF. Despite severe hepatic dysfunction, serum TPO levels were initially normal and increased during hospitalization in acetaminophen-induced ALF, but did not prevent the development of thrombocytopenia.

Role of plasma thrombopoietin level in thrombocytopenia of postoperative biliary atresia patients

BACKGROUND/PURPOSE

To evaluate if thrombocytopenia may be related to plasma thrombopoietin level (P-TPO) in postoperative biliary atresia (BA).

METHODS

Forty-three postoperative BA patients aged 1 to 20 years were included. P-TPO was measured by enzyme immunoassay. P-TPO was compared with platelet counts (Plt), Child's classification, presence of splenomegaly, and liver function tests.

RESULTS

P-TPO significantly correlated with Plt, child's classification, serum albumin, and cholinesterase level, respectively. In 4 patients undergoing portal decompression procedure, preoperative and postoperative Plt and P-TPO were 87.5 +/- 69.1 x 10(3) and 50.3 +/- 28.0, 118.8 +/- 62.3 x 10(3)/mm3, and 53.0 +/- 55.0 pg/mL, respectively, without significant difference. In 6 patients undergoing liver transplantation (LTx), Plt and P-TPO after LTx was 157.5 +/- 83.5 x 10(3) and 143.5 +/- 75.2, respectively, which were significantly higher than those before LTx (55.0 +/- 15.6 x 10(3)/mm3 and 53.2 +/- 32.9 pg/mL).

CONCLUSION

Thrombocytopenia in postoperative BA may be caused by decreased plasma TPO level in accordance with the severity of liver dysfunction rather than hypersplenism.

Thrombopoietin serum levels are elevated in patients with hepatitis B/C infection compared to other causes of chronic liver disease

BACKGROUND/AIMS

Thrombocytopenia in patients with advanced liver disease may stem from a deficient hepatic thrombopoietin production.

METHODS

We determined the relationship between thrombopoietin, thrombocytopenia, aetiology and extent of liver damage by incorporating serum thrombopoietin measurements in the pretransplant evaluation of 111 patients with liver disease.

RESULTS

The extent of thrombocytopenia was related to the underlying cause of disease. The platelet count directly correlated with factor V, II, fibrinogen, and PTT, and a negative correlation was found for splenic size and Child's stage. The thrombopoietin concentrations were age-dependent, and no significant difference resulted between the median thrombopoietin level of liver disease patients with age-matched healthy controls. Thrombopoietin concentrations and platelet counts were not correlated. Although noncirrhotic patients had higher platelet counts than those with Child's A-C cirrhosis (p < 0.001, U-test), no such difference was found in thrombopoietin levels. Patients with hepatitis B and/or C had lower platelet counts compared to patients with nonviral diseases (p < 0.001), and their median thrombopoietin concentrations were significantly higher (p < 0.001).

CONCLUSION

We conclude that thrombocytopenia in patients with liver disease is unlikely to be explained only based on a deficient hepatic production of thrombopoietin. Patients with chronic viral hepatitis have significantly elevated thrombopoietin levels; the involved pathomechanisms require further study.

The role of the liver in the production of thrombopoietin compared with erythropoietin

The liver plays an important role in the production of haemopoietic hormones. It acts as the primary site of synthesis of erythropoietin (EPO) in the fetal stage, and it is the predominant thrombopoietin (TPO)-producing organ for life. In contrast to that of EPO and other liver proteins, the hepatic synthesis of TPO is influenced little by external signals. Hepatocytes express the TPO gene in a constitutive way, i.e. irrespective of the level of platelets in blood. Megakaryocytes and platelets remove the hormone from blood by means of their high-affinity TPO receptors. Normally, the plasma level of TPO is relatively low ( approximately 10(-12) mol/l). However, in thrombocytopenic states due to marrow failure or bleeding, the concentration of circulating TPO may increase greatly. The simple feedback regulation by TPO and its target cells is efficient in maintaining constant platelet numbers in healthy people. Persisting thrombocytopenia develops only in severe liver or marrow failure. On the other hand, an increase in circulating TPO and interleukin 6 (IL-6) may cause reactive thrombocytosis in inflammatory diseases, including cancer. The indications for recombinant human thrombopoietin (rHuTPO) therapy and its impact on transfusion medicine are still under investigation.

Platelet transfusions in the neonatal intensive care unit:factors predicting which patients will require multiple transfusions

BACKGROUND

Previous studies suggest that recombinant thrombopoietin (rTPO) will increase platelet production in thrombocytopenic neonates. However, the target populations of neonates most likely to benefit should be defined. Studies suggest that rTPO will not elevate the platelet count until 5 days after the start of treatment. Therefore, the neonates who might benefit from rTPO are those who will require multiple platelet transfusions for more than 5 days. This study was designed to find means of prospectively identifying these patients.

STUDY DESIGN AND METHODS

A historic cohort study of all patients in the neonatal intensive care unit (NICU) at the University of Florida who received platelet transfusions from January 1, 1997, through December 31, 1998, was conducted.

RESULTS

Of the 1389 patients admitted to the NICU during the study period, 131 (9.4%) received platelet transfusions. Seventeen were treated with extracorporeal membrane oxygenation and were excluded from further analysis. Of the remaining 114 patients, 55 (48%) received one transfusion and 59 (52%) received more than one transfusion (21 had >4). None of the demographic factors examined predicted multiple platelet transfusions. However, two clinical conditions did; liver disease and renal insufficiency. Neonates who received one platelet transfusion had a relative risk of death 10.4 times that in neonates who received none (p = 0.0001). Neonates who received >4 platelet transfusions had a risk of death 29.9 times that in those who received no transfusions (p = 0.0001).

CONCLUSION

NICU patients with liver disease or renal insufficiency who receive one platelet transfusion are likely to receive additional transfusions. Therefore, these patients constitute a possible study population for a Phase I/II rTPO trial.

Hypersplenism

Cytopenias in liver disease are a common finding. In the past they have mostly been attributed to pooling and/or destruction of blood cells in the enlarged spleen, leading to the term 'hypersplenism'. With recent advances in the understanding of the physiology of blood formation, in particular with the discovery of several haematopoietic growth factors, new insight into the pathophysiology of blood cell derangements in liver disease has been obtained. Recombinant haematopoietic growth factors present new opportunities for support of the haematopoietic system, which is required because of toxic antiviral therapies or surgical interventions in these patients.

Thrombopoietin and chemokine mRNA expression in patient post-chemotherapy and in vitro cytokine-treated marrow stromal cell layers

CD34(+) cells and megakaryocyte progenitors were lower in marrow from patients after hematological recovery from the first cycle of 5-fluorouracil, leucovorin, adriamycin, cyclophosphamide (FLAC) chemotherapy plus PIXY321 (GM-CSF/interleukin 3; IL-3 hybrid) than in FLAC + GM-CSF or pre-FLAC marrows. Marrow stromal layers, an in vitro model of the marrow microenvironment, express a combination of stimulatory and inhibitory factors that modulate hematopoietic progenitor cell proliferation and differentiation. The TaqMan assay and quantitative reverse transcriptase-polymerase chain reaction were used to measure monocyte chemoattractant protein-1 (MCP-1), melanoma stimulatory growth activity, and monokine inducible by interferon-gamma (Mig) (inhibitory chemokines for primitive or megakaryocyte progenitors) mRNA levels in in vitro PIXY and GM-CSF-treated and patient post-FLAC marrow stromal layers. Chemokine mRNA was increased after in vitro GM-CSF and to a lesser extent after PIXY treatment. MCP-1 mRNA levels were fivefold higher in FLAC + PIXY than in FLAC + GM-CSF layers, and Mig mRNA was elevated in FLAC + GM-CSF layers. Thrombopoietin (TPO), insulin-like growth factor I (IGF-I), and IGF-II (stimulatory factors for primitive and megakaryocyte progenitors) mRNA were also measured. TPO mRNA levels were 30% lower in GM-CSF and PIXY-pretreated than in control layers with no decrease in IGF mRNA. TPO mRNA in stromal layers of patients who developed grade 3 thrombocytopenia (platelets < 20 x 10(9)/l) during the third cycle of FLAC was only 24% of levels in stromal layers of marrow from other post-FLAC patients. Results demonstrate that patient and in vitro treatment had modulatory effects on TPO and chemokine mRNA expression in marrow stromal layers.

Expression of hepatic thrombopoietin mRNA in primary cultured hepatocytes and in rats with acute liver injury or bone marrow suppression with or without cirrhosis

BACKGROUND AND AIMS

The main causes of thrombocytopenia in cirrhosis are thought to be platelet destruction and the reduction of thrombopoietin (TPO) expression in the liver. The mechanisms by which levels of TPO mRNA are regulated in cirrhosis have not been elucidated. In this study, we investigated some possible mechanisms.

METHODS

We used three experimental models: bone marrow suppression, acute liver injury and primary cultured hepatocytes. We used northern blots to assess the kinetics of TPO mRNA expression in the livers of irradiated rats (with and without cirrhosis) in acute liver injury and in primary cultured hepatocytes treated with hepatotoxin or cytokines.

RESULTS

Although the bone marrow was hypocellular, there was no apparent enhancement of TPO mRNA expression in the irradiated rats with cirrhotic livers compared with the unirradiated rats with cirrhotic livers. There were no conspicuous changes in hepatic TPO mRNA expression between the livers of the control rats and the three models of acute liver injury. There were no conspicuous changes in the levels of TPO mRNA between control hepatocytes and hepatocytes treated with hepatotoxin or cytokines.

CONCLUSIONS

Our results suggest that bone marrow is not a regulator of hepatic TPO production in cirrhosis. The reduced TPO mRNA expression found in cirrhotic rats may not result merely from serious cellular damage; it may be associated with cirrhosis-specific regulatory mechanisms for the expression of the TPO gene. Further studies are needed to search for other factors that may induce reduced TPO expression.

Hepatic thrombopoietin mRNA levels in acute and chronic liver failure of childhood

The liver is the main production site of the hormone thrombopoietin (TPO), the major regulator of megakaryopoiesis. To investigate the role of an impaired TPO gene expression in the pathogenesis of thrombocytopenia in pediatric patients suffering from liver failure, we measured hepatic TPO mRNA in children with acute or chronic end-stage liver disease undergoing orthotopic liver transplantation. Tissue samples for RNA extraction were obtained from 12 children with compensated cirrhosis (CC), 22 children with decompensated cirrhosis (DC), and 9 children with acute liver failure (ALF). TPO mRNA was quantitated by competitive polymerase chain reaction (PCR), following reverse transcription (RT). Furthermore, in 9 children with ALF, serum TPO levels were measured by enzyme-linked immunosorbent assay before and 10 to 14 days after liver transplantation. The hepatic TPO mRNA concentration was highest in children with CC (median, 50.9 amol/micrograms RNA). This value was significantly reduced in children with DC (30.2 amol/micrograms RNA) or ALF (13.8 amol/micrograms RNA). Children with ALF (139 cells/nL) or DC (200 cells/nL) had lower platelet counts than children with CC (368 cells/nL). The serum TPO concentration increased from a median of 156 pg/mL in patients with ALF to 547 pg/mL after liver transplantation. These results show that the thrombocytopenia in children with liver failure is associated with reduced hepatic TPO mRNA levels. It remains to be investigated whether the serum TPO level and platelet counts are markers for the severity of liver damage that may serve as a prognostic indicator.