Kinetics and in vivo distribution of 111-In-labelled autologous platelets in chronic hepatic disease: mechanisms of thrombocytopenia

Platelet, Antiplatelet Therapy and Metabolic Dysfunction-Associated Steatotic Liver Disease: A Narrative Review

Metabolic dysfunction-associated steatotic liver disease (MASLD) is not only related to traditional cardiovascular risk factors like type 2 diabetes mellitus and obesity, but it is also an independent risk factor for the development of cardiovascular disease. MASLD has been shown to be independently related to endothelial dysfunction and atherosclerosis. MASLD is characterized by a chronic proinflammatory response that, in turn, may induce a prothrombotic state. Several mechanisms such as endothelial and platelet dysfunction, changes in the coagulative factors, lower fibrinolytic activity can contribute to induce the prothrombotic state. Platelets are players and addresses of metabolic dysregulation; obesity and insulin resistance are related to platelet hyperactivation. Furthermore, platelets can exert a direct effect on liver cells, particularly through the release of mediators from granules. Growing data in literature support the use of antiplatelet agent as a treatment for MASLD. The use of antiplatelets drugs seems to exert beneficial effects on hepatocellular carcinoma prevention in patients with MASLD, since platelets contribute to fibrosis progression and cancer development. This review aims to summarize the main data on the role of platelets in the pathogenesis of MASLD and its main complications such as cardiovascular events and the development of liver fibrosis. Furthermore, we will examine the role of antiplatelet therapy not only in the prevention and treatment of cardiovascular events but also as a possible anti-fibrotic and anti-tumor agent.

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.

Endotheliopathy of liver sinusoidal endothelial cells in liver disease

Liver is the largest solid organ in the abdominal cavity, with sinusoid occupying about half of its volume. Under liver disease, hemodynamics in the liver tissue dynamically change, resulting in injury to liver sinusoidal endothelial cells (LSECs). We discuss the injury of LSECs in liver diseases in this article. Generally, in noninflamed tissues, vascular endothelial cells maintain quiescence of circulating leukocytes, and unnecessary blood clotting is inhibited by multiple antithrombotic factors produced by the endothelial cells. In the setting of inflammation, injured endothelial cells lose these functions, defined as inflammatory endotheliopathy. In chronic hepatitis C, inflammatory endotheliopathy in LSECs contributes to platelet accumulation in the liver tissue, and the improvement of thrombocytopenia by splenectomy is attenuated in cases with severe hepatic inflammation. In COVID-19, LSEC endotheliopathy induced by interleukin (IL)-6 trans-signaling promotes neutrophil accumulation and platelet microthrombosis in the liver sinusoids, resulting in liver injury. IL-6 trans-signaling promotes the expression of intercellular adhesion molecule-1, chemokine (C-X-C motif) ligand (CXCL1), and CXCL2, which are the neutrophil chemotactic mediators, and P-selectin, E-selectin, and von Willebrand factor, which are involved in platelet adhesion to endothelial cells, in LSECs. Restoring LSECs function is important for ameliorating liver injury. Prevention of endotheliopathy is a potential therapeutic strategy in liver disease.

Efficiently Restored Thrombopoietin Production by Ashwell-Morell Receptor and IL-6R Induced Janus Kinase 2/Signal Transducer and Activator of Transcription Signaling Early After Partial Hepatectomy

BACKGROUND AND AIMS

Thrombocytopenia has been described in most patients with acute and chronic liver failure. Decreased platelet production and decreased half-life of platelets might be a consequence of low levels of thrombopoietin (TPO) in these patients. Platelet production is tightly regulated to avoid bleeding complications after vessel injury and can be enhanced under elevated platelet destruction as observed in liver disease. Thrombopoietin (TPO) is the primary regulator of platelet biogenesis and supports proliferation and differentiation of megakaryocytes.

APPROACH AND RESULTS

Recent work provided evidence for the control of TPO mRNA expression in liver and bone marrow (BM) by scanning circulating platelets. The Ashwell-Morell receptor (AMR) was identified to bind desialylated platelets to regulate hepatic thrombopoietin (TPO) production by Janus kinase (JAK2)/signal transducer and activator of transcription (STAT3) activation. Two-thirds partial hepatectomy (PHx) was performed in mice. Platelet activation and clearance by AMR/JAK2/STAT3 signaling and TPO production were analyzed at different time points after PHx. Here, we demonstrate that PHx in mice led to thrombocytopenia and platelet activation defects leading to bleeding complications, but unaltered arterial thrombosis, in these mice. Platelet counts were rapidly restored by up-regulation and crosstalk of the AMR and the IL-6 receptor (IL-6R) to induce JAK2-STAT3-TPO activation in the liver, accompanied by an increased number of megakaryocytes in spleen and BM before liver was completely regenerated.

CONCLUSIONS

The AMR/IL-6R-STAT3-TPO signaling pathway is an acute-phase response to liver injury to reconstitute hemostasis. Bleeding complications were attributable to thrombocytopenia and platelet defects induced by elevated PGI₂ , NO, and bile acid plasma levels early after PHx that might also be causative for the high mortality in patients with liver disease.

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.

Thrombocytopenia as a marker of liver steatosis in a low-endemic area for schistosomiasis mansoni

Introduction:

Thrombocytopenia is commonly found in patients living in highly endemic areas for Schistosoma mansoni. Recently, different degrees of liver steatosis have also been associated with low platelet counts worldwide. We investigated the association of platelet counts with hepatosplenic schistosomiasis and with liver steatosis in an area of low prevalence of schistosomiasis in Brazil.

Method:

Pains, a city in the state of Minas Gerais, Brazil, had a population of 8,307 inhabitants and a schistosomiasis prevalence of 8%. Four micro-areas comprising 1,045 inhabitants were selected for this study. Blood sample was collected and a complete blood count (CBC) was performed. Eighty-seven (87) patients had low platelet counts (group 1 - 8.3%) and 94 volunteers presenting normal CBC were randomized (group 2 - 8.9%). They underwent clinical and ultrasound examinations. Liver steatosis was determined as either present or absent using abdominal ultrasound. A spleen > 12 cm in length, measured by ultrasound (US), was considered to be increased. Data collected were analyzed using SPSS software version 19.0.

Results:

Twenty-two patients (22/25.3%) in group 1 had liver steatosis compared with 11 volunteers (11.7%) in group 2 (p=0.02). Hepatosplenic schistosomiasis was diagnosed in two patients (p>0.05).

Conclusion:

Thrombocytopenia was not a good marker of hepatosplenic schistosomiasis mansoni in a low prevalence area in Brazil. Liver steatosis was associated with thrombocytopenia in our study.

Splenectomy before adult liver transplantation: a retrospective study

BACKGROUND

A considerable number of patients with portal hypertension (PHT) have to undergo splenectomy because they do not meet the requirements for liver transplantation (LT) or cannot find a suitable liver donor. However, it is not known whether pre-transplantation splenectomy may create occult difficulties for patients who require LT in future.

METHODS

We analyzed 1059 consecutive patients who underwent adult liver transplantation (ADLT). Patients with pre-transplantation splenectomy Sp(+) and without splenectomy Sp(-) were compared using a propensity score analysis to create the best match between groups.

RESULTS

There were no differences between patients in group Sp(+) and group Sp(-) with respect to the main post-operative infections (12.20% vs. 15.85%, P = 0.455), and the incidence of major complications (6.10% vs. 10.98%, P = 0.264). The post-operative platelet count was significantly higher in group Sp(+) (P = 0.041), while group Sp(-) had a higher rate of post-operative thrombocytopenia (91.46% vs. 74.39%, P = 0.006) and early allograft dysfunction (EAD) (23.20% vs. 10.98%, P = 0.038). The 5-year overall survival rates were similar in groups Sp(-) and Sp(+) (69.7% vs. 67.6%, P = 0.701).

CONCLUSIONS

Compared with Sp(-), the risk of infection and post-operative complications in group Sp(+) was not increased, while group Sp(-) had a higher rate of post-operative EAD. Moreover, pre-transplantation splenectomy is very effective for the prevention of thrombocytopenia after LT. Pre-transplantation splenectomy is recommended in cases with risky PHT patients without appropriate source of liver for LT.

Accumulation of platelets in the liver may be an important contributory factor to thrombocytopenia and liver fibrosis in chronic hepatitis C

BACKGROUND

Thrombocytopenia is a marked feature of chronic liver disease and cirrhosis. We tried to clarify whether an accumulation of platelets in the liver contributes to thrombocytopenia and liver fibrosis in chronic liver disease.

METHODS

Thirty-eight patients who underwent hepatectomy for hepatocellular carcinoma (HCC) with hepatitis C virus infection were included. The locations of platelets and Kupffer cells and the expression of platelet-derived growth factor (PDGF) receptor-β and smooth muscle actin (SMA) were identified by immunohistochemistry. Perisinusoidal mesenchymal cells that express PDGF receptor-β and SMA were interpreted as transformed hepatic stellate cells (HSCs).

RESULTS

Patients with cirrhosis had a more extensive platelet area in the liver compared to controls (5601 ± 5611 vs. 564 ± 361 μm(2), p = 0.02), although the blood platelet count significantly decreased along with the progression of liver fibrosis. In cirrhotic liver, most platelets were present in the sinusoidal space of the periportal area with inflammation, where HSCs expressing PDGF receptor-β were frequently observed. In addition, the platelet and Kupffer cell areas were significantly smaller in cancerous tissue than those in noncancerous tissues (platelet area: 492 ± 823 vs. 3643 ± 4055 μm(2), p = 0.001; Kupffer cell area: 450 ± 841 vs. 3012 ± 3051 μm(2), p = 0.001).

CONCLUSIONS

The accumulation of platelets in the liver with chronic hepatitis may be involved in thrombocytopenia and liver fibrosis through the activation of HSCs. In addition, our findings also indicate that both platelets and Kupffer cells decrease in HCC tissues.

The clinical significance of JAK2V617F mutation for Philadelphia-negative chronic myeloproliferative neoplasms in patients with splanchnic vein thrombosis

Polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF), collectively known as Philadelphia-negative (Ph-negative) chronic myeloproliferative neoplasms (MPNs), MPNs represent the most common causes of splanchnic vein thrombosis (SVT), including Budd-Chiari syndrome (BCS) and portal vein thrombosis (PVT). The JAK2V617F mutation has been demonstrated in most of the Ph-negative chronic MPNs. The study objective was to assess the diagnostic value of JAK2V617F mutation in patients with SVT in a group of 68 patients with SVT (42 PVT,19 BCS, 7 combined PVT and BCS). By DNA-melting curve analysis, the JAK2V617F mutation was detected in 42.1 % of BCS, 38.1 % of PVT and 71.4 % of combined PVT and BCS groups. Thirteen of 15 (86.6 %) SVT patients with overt MPN and 16 of 53 (30.1 %) SVT patients without overt MPN (patients with either normal blood counts or cytopenias), including 6 of 16 with BCS (37.5 %), 7 of 33 with PVT (21.2 %) and 3 of 4 with combined BCS and PVT (75 %) possessed JAK2V617F mutation. A substantial proportion of patients with SVT were recognized as carriers of the JAK2V617F mutation despite the absence of overt signs of MPN. Receiver Operating Characteristic (ROC) curve analysis determined a platelet count of 190,000 mm(3) (area under the curve; AUC = 0.724, p = 0.002) and a white blood cell (WBC) count of 8,150 mm(3) (AUC = 0.76, p = 0.001) as the best cut-off values for the highest sensitivity and specificity ratios of the JAK2V617F mutation in patients with SVT. A significant positive correlation existed between the JAK2V617F mutational status of SVT patients and the WBC and platelet counts. Our results imply that JAK2V617F mutation screening should be an initial test for MPN in patients with SVT.

Platelet count for predicting fibrosis in nonalcoholic fatty liver disease

BACKGROUND

The severity of liver fibrosis is known to be a good indicator for surveillance, and for determining the prognosis and optimal treatment of nonalcoholic fatty liver disease (NAFLD). However, it is virtually impossible to carry out liver biopsies in all NAFLD patients. The purpose of this study was to investigate the clinical usefulness of measuring the platelet count for predicting the severity of liver fibrosis in a large retrospective cohort of Japanese patients with NAFLD.

METHODS

A total of 1,048 patients with liver-biopsy-confirmed NAFLD seen between 2002 and 2008 were enrolled from nine hepatology centers in Japan. Laboratory evaluations were performed for all patients.

RESULTS

A linear decrease of the platelet count with increasing histological severity of hepatic fibrosis was revealed. The area under the receiver operating characteristic curve estimating the diagnostic performance of the platelet count for hepatic fibrosis Stage 3 was 0.774 (optimal cutoff value, 19.2 × 10(4)/μl; sensitivity, 62.7%; specificity, 76.3%), and that for Stage 4 was 0.918 (optimal cutoff value, 15.3 × 10(4)/μl; sensitivity, 80.5%; specificity, 88.8%).

CONCLUSIONS

The platelet count may be an ideal biomarker of the severity of fibrosis in NAFLD patients, because it is simple, easy to measure and handle, cost-effective, and accurate for predicting the severity of fibrosis. Furthermore, by using the platelet count cutoff value validated in our multiple large trials, efficient recruitment of NAFLD patients may be facilitated.

Mean platelet volume as a fibrosis marker in patients with chronic hepatitis B

INTRODUCTION

Many noninvasive tests have been studied for the diagnosis and determining the liver fibrosis score (LFS). In this study, we aimed to research the correlation of mean platelet volume (MPV) and stage of liver fibrosis in patients with chronic hepatitis B (CHB).

PATIENTS AND METHODS

Fifty-nine patients with CHB were enrolled retrospectively into the study. Age-sex matched 25 healthy subjects were used as control group. The following data were obtained from computerized patient registry database: HBV-DNA level, hepatitis B e-antigen seropositivity, liver enzymes and function tests, white blood cell count, platelet count, hemoglobin, histological activity index, LFS, and MPV. Patients were divided into two groups: patients without significant fibrosis (F0, F1, or F2) (Group 1) and patients with advanced fibrosis (F3, F4) (Group 2).

RESULTS

A statistically significant increase in MPV was seen in patients with CHB compared with healthy controls (8.49±0.84 fl vs.7.65±0.42 fl, P<0.001). Receiver operating characteristic curve analysis suggested that the optimum MPV level cut-off points for CHB was 8.0 fl, with sensitivity, specificity, PPV, and NPV of 68, 76, 86, and 50%, respectively. MPV levels were significantly higher in Group 2 (8.91±0.94 fl, P: 0.009) compared with Group 1 (8.32±0.74 fl). ROC curve analysis suggested that the optimum MPV level cut-off points for Group 2 was 8.45 fl, with sensitivity, specificity, positive and negative predictive value of 77, 59, 45, and 85%, respectively. Multivariable logistic regression model, which consisted of HAI, ALT, HBV-DNA, platelet count, and MPV, was performed. We showed that MPV was independently associated with advanced fibrosis (P: 0.031).

CONCLUSION

We suggest that MPV might help in the assessment of fibrosis in CHB. It should not be considered a stand-alone test for this use owing to nonspecificity with other diseases.

Thrombocytopenia is more severe in patients with advanced chronic hepatitis C than B with the same grade of liver stiffness and splenomegaly

BACKGROUND AND AIM

The mechanism responsible for thrombocytopenia in chronic liver diseases (CLD) is not yet fully understood. The prevalence of thrombocytopenia has been reported to be higher in patients with hepatitis C virus-related hepatocellular carcinoma (CLD-C) than in those with hepatitis B virus-related hepatocellular carcinoma (CDC-B). We have examined the potential difference in thrombocytopenia between patients with CLD-B and those with CLD-C in terms of liver fibrosis adjustment and splenomegaly.

METHODS

The study cohort consisted of 102 patients with CLD-B and 143 patients with CLD-C were enrolled. Liver stiffness, which is reported to be well correlated with the degree of liver fibrosis, was measured by transient elastography.

RESULTS

The analysis of covariance with liver stiffness as a covariate revealed that the platelet count was lower in CLD-C patients than in CLD-B patients. Following stratification for liver stiffness, thrombocytopenia was found to be more severe in CLD-C patients than CLD-B patients with advanced liver stiffness, whereas the degree of splenomegaly was not significantly different. The plasma thrombopoietin level was not different between CLD-B and CLD-C patients with advanced liver stiffness, and the immature platelet number was lower in CLD-C patients despite thrombocytopenia being more severe in these patients.

CONCLUSIONS

CLD-C patients with advanced liver stiffness presented with more severe levels of thrombocytopenia than CLD-B patients even with the same grade of splenomegaly. Impaired platelet production rather than enhanced platelet destruction may underlie the mechanism responsible for thrombocytopenia in patients with CLD.

Review article: blood platelet number and function in chronic liver disease and cirrhosis

BACKGROUND

The liver plays a central role in coagulation and fibrinolysis but is also closely intertwined with the function and number of blood platelets.

AIM

To describe and integrate all literature concerning blood platelets and liver disease by performing a thorough literature research.

METHODS

A thorough literature research on 'blood platelets' and 'liver disease' was performed.

RESULTS

Thrombocytopenia is a marked feature of chronic liver disease and cirrhosis. Traditionally, this thrombocytopenia was attributed to passive platelet sequestration in the spleen. More recent insights suggest an increased platelet breakdown and to a lesser extent decreased platelet production plays a more important role. Besides the reduction in number, other studies suggest functional platelet defects. This platelet dysfunction is probably both intrinsic to the platelets and secondary to soluble plasma factors. It reflects not only a decrease in aggregability, but also an activation of the intrinsic inhibitory pathways. The net effect, finally, is a decreased platelet function in the various types of chronic liver diseases and cirrhosis. Finally, recent data suggest that platelets are not only affected by but can also contribute to the liver disease process, as for instance, in viral hepatitis and cholestatic liver disease.

CONCLUSION

Platelet research in liver disease is a growing area of investigation and could provide new pathophysiological insights.

Laparoscopic splenectomy reverses thrombocytopenia in patients with hepatitis C cirrhosis and portal hypertension

Pegylated-interferon (IFN) plus ribavirin remains the most effective therapeutic regimen for patients with chronic hepatitis C infection. Thrombocytopenia is a common side effect of this treatment, often leading to discontinuation of a potentially curative therapy. We sought to determine the safety and efficacy of laparoscopic splenectomy in correcting thrombocytopenia, thus allowing completion of IFN therapy. Data were collected prospectively from September 2000 to May 2003 on all patients undergoing laparoscopic splenectomy for thrombocytopenia associated with IFN therapy and/or hepatitis C cirrhosis with portal hypertension. Demographic data, model of end-stage liver disease (MELD) score, platelet count, operative time, blood loss, spleen weight, complications, length of stay, and follow-up time were calculated. Eleven patients (7 men, 4 women) underwent laparoscopic splenectomy; their mean age was 45.4 years (range 27 to 55 years) and mean body mass index was 27 kg/m(2) (range 21 to 44 kg/m(2)). All patients were Child's class A, with a mean preoperative MELD score of 9.1 (range 6 to 11). Mean operative time was 189 minutes (range 70 to 245 minutes), and blood loss averaged 141 ml (range 10 to 600 ml). A hand-assisted laparoscopic technique was used in four cases. Six patients received empiric intraoperative platelet administration. None required transfusion with packed red cells. Splenic weight averaged 1043 g (range 245 to 1650 g). Average length of stay was 2.6 days (range 1 to 6 days). Four patients had the following minor postoperative complications: self-limited atrial fibrillation (n=1), trocar site cellulitis (n=1), and atelectasis (n=2). There have been no major complications over an average follow-up of 11 months (range 1 to 18 months). Mean postoperative MELD score was 8.3 (range 6 to 10). Platelet counts improved from a preoperative mean of 55000/ul (16000 to 88000/microl) to 439000/microl (200000 to 710000/microl) postoperatively and have remained above 100000/microl (104000 to 397000/microl) during subsequent pegylated-IFN therapy. Three patients have completed a full course of IFN therapy and have obtained a sustained virologic response. Treatment is ongoing in the remaining patients. Laparoscopic splenectomy is safe in the setting of portal hypertension and thrombocytopenia associated with chronic hepatitis C infection. It can be performed with little blood loss, no need for red cell transfusion, and minimal perioperative morbidity. Laparoscopic splenectomy appears to effectively reverse thrombocytopenia and may allow these patients to safely complete IFN therapy.

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.

Diagnostic value of serum type IV collagen test in comparison with platelet count for predicting the fibrotic stage in patients with chronic hepatitis C

BACKGROUND AND AIM

The serum type IV collagen test is now used as a diagnostic aid for the detection of liver fibrosis and cirrhosis. Recently, a platelet count has been reported to be a useful marker for assessing the fibrotic stage in chronic hepatitis C. The aim of this study was to compare the usefulness of the serum type IV collagen test and platelet count for diagnosing the fibrotic stage in chronic hepatitis C patients.

METHODS

The diagnostic values were assessed by the use of receiver operating characteristic (ROC) analysis in 165 patients with chronic hepatitis C, with the exception of those patients with cirrhosis.

RESULTS

The serum type IV collagen level increased, and the platelet count decreased significantly with the progression of fibrosis staging. As judged from ROC curves, the serum type IV collagen test was more useful than the platelet count for differentiating moderate or severe fibrosis from no or mild fibrosis. At a cut-off value of 110 ng/mL, the serum type IV collagen test had an overall diagnostic accuracy of 75%, while at a cut-off value of 16 x 10(4)/mm(3), the platelet count had a diagnostic accuracy of 70%. The serum type IV collagen test and platelet count were similar in differentiating severe fibrosis from no, mild or moderate fibrosis. Both serum type IV collagen (at a cut-off value of 130 ng/mL) and platelet count (at a cut-off value of 14 x 10(4)/mm(3)) had a diagnostic accuracy of 73%.

CONCLUSION

The serum type IV collagen test was slightly superior to the platelet count for assessing the fibrotic stage in patients with chronic hepatitis C.

Hepatic fibrosis plays a central role in the pathogenesis of thrombocytopenia in patients with chronic viral hepatitis

The pathogenesis of thrombocytopenia in chronic hepatitis is not well known. This study evaluated the relationship between liver injury, serum thrombopoietin, splenomegaly and thrombocytopenia in chronic viral hepatitis. Two hundred and nine patients were enrolled, 85 with splenomegaly and 124 without. Thrombocytopenia was present in 71% and 23% of patients with or without splenomegaly respectively. In subjects with low platelet count, those with splenomegaly showed significantly lower platelet numbers than those without splenomegaly. The spleen size correlated with portal hypertension. An inverse correlation between spleen size and platelet count was observed (r = -0.54; P < 0.0001). In patients without splenomegaly, thrombocytopenia was associated with the grade of fibrosis; platelet counts were the highest in patients with fibrosis 0-2, lower in those with grade 3 (P < 0.008) and lowest in those with grade 4 (P < 0.05). These findings were independent of demographic and biochemical characteristics, hepatic necroinflammatory activity, portal hypertension and splenomegaly. Patients with normal platelet counts showed higher thrombopoietin levels than those with low platelet counts (P < 0.0001). An inverse correlation between thrombopoietin levels and fibrosis grade was observed (r = - 0.50; P < 0.0001). Median thrombopoietin levels were 58 and 27 pg/ml for fibrosis grade 0-1 and grade 4 respectively (P < 0.001). These data indicate that advanced hepatic fibrosis, causing an altered production of thrombopoietin and portal hypertension, plays the central role in the pathogenesis of thrombocytopenia in chronic viral hepatitis.

Deleted form of hepatocyte growth factor (dHGF) increases the number of platelets in rats with liver cirrhosis

The effect of the deleted form of hepatocyte growth factor (dHGF) on thrombopoiesis was studied in rats. When normal rats were injected with dHGF (0.5 mg/kg i.v. twice a day), the number of platelets increased to about 1.5-fold the initial level. In addition, the treatment with dHGF (0.5 mg/kg i.v. twice daily) significantly increased the number of platelets in rats with liver cirrhosis induced by carbon tetrachloride and phenobarbital. When dHGF was given to rats at a dose of 0.05 or 0.5 mg/kg from the beginning of the induction of dimethylnitrosamine liver cirrhosis to day 28, dHGF dose-dependently ameliorated thrombocytopenia and completely prevented it at a dose of 0.5 mg/kg. These results indicate that dHGF may be applicable to the treatment of thrombocytopenia associated with liver cirrhosis.

Mechanisms of thrombocytopenia induced by interferon therapy for chronic hepatitis B

To clarify the mechanisms of thrombocytopenia observed in patients with chronic hepatitis B treated with interferon. We studied six patients with chronic active hepatitis B who received intramuscular injections of natural interferon-alpha (3 or 5 million IU/ day) for 4 weeks. Peripheral blood platelet counts, bone marrow findings, and platelet kinetics, determined using 111In-labeled platelets, were analyzed. Platelets decreased significantly 1 week after the beginning of treatment and remained decreased until the completion of treatment. The number of nucleated cells and megakaryocytes in bone marrow decreased in three of five patients studied during treatment. The kinetic study showed platelet survival time to be 8.1 +/- 1.3 days (range, 5.8-10.0). One day after platelet injection, platelets accumulated predominantly in the splenic area in all patients, whereas hepatic accumulation was predominant 7 days after injection in three of the six patients. Thrombocytopenia during interferon treatment arises from the inhibition of stem cell proliferation and differentiation in the bone marrow and from the capture of platelets by the liver.

Course of thrombocytopenia of chronic liver disease after transjugular intrahepatic portosystemic shunts (TIPS). A retrospective analysis

Thrombocytopenia associated with chronic liver disease presents a difficult management issue. Most reports conclude that portocaval and distal splenorenal shunts do not improve platelet counts in this setting. The response of thrombocytopenia after transjugular intrahepatic portosystemic shunt placement has not been studied. All platelet counts of 21 patients undergoing intrahepatic shunt placement were determined retrospectively to accumulate values at one month prior to procedure, weekly for the first month after the procedure, and monthly thereafter to six months. Comparison of pre- and postshunt platelet means showed a significant increase in counts in patients with a postshunt portal pressure gradient < 12 mm Hg, with the increment evident by one week after the procedure. This response was not seen when preshunt thrombocytopenia was used as the lone variable. This study suggests that the transjugular intrahepatic portosystemic shunt may improve the thrombocytopenia associated with liver cirrhosis when these pressure gradients are attained.

In vitro function of indium-111 oxine-labeled human monocytes

Mononuclear phagocytes (monocytes and macrophages) are widely distributed throughout the body. Indium-111 (111In) oxine has been a useful radioactive label in studies of in vivo cellular kinetics and distribution. In preparation for in vivo monocyte investigations in humans, this study was designed to determine the effects of labeling human blood monocytes with 111In on their function in vitro. The monocytes labeled with an efficiency of 57.9 +/- 14.2% (range of 47-95%). The 111In eluted from the cells at a rate of 0.25%/h over 48 h in vitro. The labeled monocytes had a slight, but statistically significant, reduction in their ability to phagocytize or mediate antibody-dependent cellular cytotoxicity of antibody-coated sheep erythrocytes. The labeled cells were not different than control monocytes with respect to viability (trypan blue exclusion and lactate dehydrogenase release), adherence to plastic, hydrogen peroxide production, chemotaxis to N-formyl methionylleucylphenylalanine, and antibody-independent lysis of the tumor cells U937 and HeLa. 111In-labeled human monocytes should be useful for in vivo studies of mononuclear phagocyte kinetics and distribution in normal and diseased subjects.