Parenchymal extinction: coagulation and hepatic fibrogenesis

Viral cirrhosis: an overview of haemostatic alterations and clinical consequences

Viral hepatitis is a major health problem worldwide, the principal cause of cirrhosis and hepatocarcinoma. Once cirrhosis occurs, the consequences of liver dysfunction and portal hypertension become evident and, sometimes, life threatening for patients. Among the various complications of liver cirrhosis, the alteration of haemostatic balance is often a hard challenge for the clinician, since it is capable to predispose both to bleeding or thrombosis. In this review, we analyze the principal aspects of procoagulant, anticoagulant and fibrinolytic capacity of cirrhotic patients, which appears to be variably altered in all these aspects, not only in the direction of a tendency to bleeding. Laboratory investigations, at present, may provide only a partial representation of this condition, because of the impossibility to obtain a test capable to furnish a global overview of the haemostatic system and to reproduce in vivo conditions. Furthermore, we describe the pathophysiological mechanisms underlying bleeding manifestations and thrombosis development in cirrhotic patients, which should be considered not only as obvious consequences of the advanced liver disease but, rather, as the result of a complex interaction between inherited and acquired factors.

The coagulation factor Xa/protease activated receptor-2 axis in the progression of liver fibrosis: a multifaceted paradigm

Hepatic fibrosis is a common response to virtually all forms of chronic liver injury independent of the etiologic agent. Despite the relatively large population of patients suffering from hepatic fibrosis and cirrhosis, no efficient and well-tolerated drugs are available for the treatment of this disorder. The lack of efficient treatment options is at least partly because the underlying cellular mechanisms leading to hepatic fibrosis are only partly understood. It is thus of pivotal importance to better understand the cellular processes contributing to the progression of hepatic fibrosis. Interestingly in this perspective, a common feature of fibrotic disease of various organs is the activation of the coagulation cascade and hepatic fibrosis is also accompanied by a local hypercoagulable state. Activated blood coagulation factors directly target liver cells by activating protease-activated receptors (PAR) thereby inducing a plethora of cellular responses like (among others) proliferation, migration and extracellular matrix production. Coagulation factor driven PAR activation thus establishes a potential link between activation of the coagulation cascade and the progression of fibrosis. The current review focuses on blood coagulation factor Xa and summarizes the variety of cellular functions induced by factor Xa-driven PAR-2 activation and the subsequent consequences for tissue repair and hepatic fibrosis.

Thrombotic risk factors and liver histologic lesions in non-alcoholic fatty liver disease

BACKGROUND/AIMS

The pathogenetic mechanisms of development of non-alcoholic steatohepatitis (NASH) and fibrosis are not clear, although thrombosis of small intrahepatic veins has been suggested to trigger liver tissue remodelling and thrombotic risk factors have been associated with more advanced fibrosis in chronic viral hepatitis (CVH). We evaluated the prevalence of thrombotic risk factors (RFs) in non-alcoholic fatty liver disease (NAFLD) and their possible association with fatty liver or NASH.

METHODS

We included 60 patients with histologically documented NAFLD and a historical cohort of 90 patients with chronic hepatitis B (n=39) or C (n=51). Thrombophilic factors were evaluated on the day of the liver biopsy.

RESULTS

One or more thrombotic RFs were detected in 37% of NAFLD patients, and >or= 2 RFs were detected in 12% of NAFLD patients, being less frequently present than in CVH patients (37% and 68%, respectively; P <or= 0.001). Among NAFLD cases, one or more thrombotic RFs were significantly more frequently present in NASH than simple fatty liver (56% vs. 8%; odds ratio [OR]: 13.8, 2.8-67.4, P<0.001). In multivariate analysis, NASH was independently associated with moderate to severe steatosis (adjusted OR: 24.3; P=0.001) and the presence of one or more thrombotic RFs (adjusted OR: 38.7; P=0.002). Fibrosis stage was worse in NASH patients with than without thrombotic RFs (2.5+/-1.1 vs. 1.3+/-1.1; P=0.002).

CONCLUSIONS

Thrombotic RFs are frequently present in patients with NAFLD and are associated with NASH and more advanced fibrosis. Such an association may have significant clinical implications, even though it is not clear yet whether it represents a primary or secondary phenomenon.

The enigma of pulmonary hypertension after splenectomy--does the megakaryocyte provide a clue?

Pulmonary hypertension is a common and debilitating condition which is increasingly being recognized in haematological patients. This is particularly so in haemolytic diseases like thalassaemia and myeloproliferative conditions like idiopathic myelofibrosis. Recently, splenectomy, which may be required for some of these conditions, have been linked to this complication although the exact pathophysiology is still not established. The manuscript explains the role of the less recognized 'lung megakaryocytes' in the development of this complication.