Immunological profile of patients with non-cirrhotic portal fibrosis

[Portosinusoidal vascular disorder: A paradigm shift]

The term portosinusoidal vascular disorder (PSVD) refers to a clinical-pathological entity that encompasses those patients with intrahepatic vascular damage without cirrhosis at risk of developing severe complications of portal hypertension. Numerous systemic diseases, genetic disorders, and toxic agents have been associated with this pathology, making its diagnosis an important clinical challenge. The recent description of uniform diagnostic criteria and a better understanding of its pathophysiology will allow for better identification of patients, even in early stages of the disease. Although there is currently no effective etiological treatment available, early diagnosis allows for the development of preventive strategies for some severe complications of portal hypertension.

What makes non-cirrhotic portal hypertension a common disease in India? Analysis for environmental factors

In India, an unexplained enteropathy is present in a majority of non-cirrhotic intrahepatic portal hypertension (NCIPH) patients. Small intestinal bacterial contamination and tropical enteropathy could trigger inflammatory stimuli and activate the endothelium in the portal venous system. Groundwater contaminated with arsenic is an environmental factor of epidemic proportions in large areas of India which has similar consequences. Von Willebrand factor (a sticky protein) expressed by activated endothelium may promote formation of platelet microthrombi and occlusion of intrahepatic portal vein branches leading to NCIPH. Environmental factors linked to suboptimal hygiene and sanitation, which enter through the gastrointestinal (GI) tract, predispose to platelet plugging onto activated endothelium in portal microcirculation. Thus, NCIPH, an example of poverty linked thrombophilia, is a disease mainly affecting the lower socio-economic strata of Indian population. Public health measures to improve sanitation, provide clean drinking water and eliminate arsenic contamination of drinking water are urgently needed. Till such time as these environmental factors are addressed, NCIPH is likely to remain 'an Indian disease'.

Noncirrhotic portal hypertension

Portal hypertension is characterized by an increase in portal pressure (> 10 mmHg) and could be a result of cirrhosis of the liver or of noncirrhotic diseases. When portal hypertension occurs in the absence of liver cirrhosis, noncirrhotic portal hypertension (NCPH) must be considered. The prognosis of this disease is much better than that of cirrhosis. Noncirrhotic diseases are the common cause of portal hypertension in developing countries, especially in Asia. NCPH is a heterogeneous group of diseases that is due to intrahepatic or extrahepatic etiologies. In general, the lesions in NCPH are vascular in nature and can be classified based on the site of resistance to blood flow. In most cases, these disorders can be explained by endothelial cell lesions, intimal thickening, thrombotic obliterations, or scarring of the intrahepatic portal or hepatic venous circulation. Many different conditions can determine NCPH through the association of these various lesions in various degrees. Many clinical manifestations of NCPH result from the secondary effects of portal hypertension. Patients with NCPH present with upper gastrointestinal bleeding, splenomegaly, ascites after gastrointestinal bleeding, features of hypersplenism, growth retardation, and jaundice due to portal hypertensive biliopathy. Other sequelae include hyperdynamic circulation, pulmonary complications, and other effects of portosystemic collateral circulation like portosystemic encephalopathy. At present, pharmacologic and endoscopic treatments are the treatments of choice for portal hypertension. The therapy of all disorders causing NCPH involves the reduction of portal pressure by pharmacotherapy or portosystemic shunting, apart from prevention and treatment of complications of portal hypertension.

Noncirrhotic portal fibrosis/idiopathic portal hypertension: APASL recommendations for diagnosis and treatment

The Asian Pacific Association for the Study of the Liver (APASL) Working Party on Portal Hypertension has developed consensus guidelines on the disease profile, diagnosis, and management of noncirrhotic portal fibrosis and idiopathic portal hypertension. The consensus statements, prepared and deliberated at length by the experts in this field, were presented at the annual meeting of the APASL at Kyoto in March 2007. This article includes the statements approved by the APASL along with brief backgrounds of various aspects of the disease.

Association of celiac disease with non-cirrhotic portal fibrosis

Both celiac disease and non-cirrhotic portal fibrosis are known to be associated with various autoimmune diseases and have numerous immunological abnormalities. Herein two patients with celiac disease having associated non-cirrhotic portal fibrosis are reported. An autoimmune link between the two conditions is likely to explain coexistence in the same patient.

Rabbit model of non-cirrhotic portal fibrosis with repeated immunosensitization by rabbit splenic extract

BACKGROUND

Non-cirrhotic portal fibrosis (NCPF) or idiopathic portal hypertension, a disease of unknown etiology, is a common cause of portal hypertension in developing countries. Attempts to understand the etiopathogenesis of NCPF by developing animal models have been made. We describe a novel approach using repeated injections of rabbit splenic extract that were obtained from a previously primed rabbit, to develop a model of NCPF.

METHODS

Twenty-eight rabbits (1.5-2.0 kg) were divided into the control (group I, n = 13) and the experimental (group II, n = 15) groups. The supernatant obtained after centrifugation of a 20% splenic homogenate, containing 6 mg protein/mL, was mixed with Freund's complete adjuvant (1:1 ratio) and injected intramuscularly to the recipient rabbits every 2 weeks for 3 months. Portal pressure was measured by inserting a cannula into the gastrosplenic vein.

RESULTS

The mean portal pressure in group II was significantly (P < 0.05) higher than group I at 1 (19.4 +/- 2.9 vs 10.4 +/- 2.2 mmHg), 3 (16.7 +/- 1.1 vs 7.2 +/- 3.6 mmHg), and 6 (20.3 +/- 5.4 vs 10.3 +/- 4.8 mmHg) months. The mean splenic weight in group II was significantly (P < 0.05) greater than group I at 1, 3 and 6 months. Histopathology of spleen showed medullary congestion, hemosidrin laden macrophages and mild fibrosis. Liver showed normal hepatocytes with mild portal lymphocytic infiltrates and Kupffer cell hyperplasia. No significant anomalies were observed in the tests of liver function at 1 and 6 months.

CONCLUSIONS

This animal model showed significant splenomegaly, with persistent rise in portal pressure without hepatic parenchymal injury, quite akin to NCPF seen in humans. This study also proposes that repeated immunostimulation may have an important role in the pathogenesis of NCPF.

Coagulation profile and platelet function in patients with extrahepatic portal vein obstruction and non-cirrhotic portal fibrosis

BACKGROUND AND AIMS

Coagulation disorders commonly develop in patients with cirrhosis of the liver. They have also been reported in patients with non-cirrhotic portal fibrosis (NCPF) and extra-hepatic portal venous obstruction (EHPVO); the two conditions with portal hypertension and near-normal liver functions. The spectrum and prevalence of coagulation abnormalities and their association with the pathogenesis of these diseases and with hypersplenism was prospectively studied.

METHODS

Eighteen EHPVO patients that included an equal number of NCPF patients and 20 healthy controls were prospectively studied. The coagulation parameters assessed included: international normalized ratio, partial thromboplastin time, and fibrinogen and fibrinogen degradation products. Platelet aggregation and malondialdehyde levels were measured.

RESULTS

Both EHPVO (83%) and NCPF (78%) patients had a significantly prolonged international normalized ratio and a decrease in fibrinogen and platelet aggregation. The EHPVO patients had a significant prolongation in partial thromboplastin time (67% patients), with increased levels of fibrinogen degradation product levels occurring in all patients; these were normal in NCPF patients. Platelet malondialdehyde levels were normal in both groups. Hypersplenism was present in four EHPVO and seven NCPF patients. It did not significantly influence the coagulation profile in either NCPF or EHPVO patients.

CONCLUSIONS

Coagulation anomalies are common and significant in both NCPF and EHPVO patients, suggestive of a mild disseminated intravascular coagulation disorder. These imbalances could be caused by chronic subclinical endotoxemia and cytokine activation after the initial portal thromboembolic event. The persistence of these abnormalities in adolescent patients indicates an ongoing coagulation derangement.

Haemostatic and immunological sequelae of portacaval shunt in rats

We have evaluated the link between haemostatic abnormalities and immune dysfunction in liver disease by evaluating parameters of cellular and humoral immunity in conjunction with coagulation profiles in rats following portacaval anastomosis, induction of portal hypertension by portal vein stenosis or by sham surgical procedures. Twelve weeks following surgery, portacaval shunted rats were markedly anaemic (8.9 +/- 0.6 g/dl; controls 12.3 +/- 1.4 g/dl, p < 0.05), had low plasma fibrinogen levels (0.6 +/- 0.3 g/l, controls 2.5 +/- 0.2 g/l p < 0.05) and markedly elevated fibrin(ogen) degradation products (FDP) titres (1/40-1/80; controls < 1/10. p < 0.05). Portal vein stenosed rats were less anaemic (11.5 +/- 0.8 g/dl), had near normal fibrinogen levels (2.1 +/- 0.3 g/l) but elevated FDP levels (1/40-1/80). Both portacaval shunted and portal vein stenosed rats had elevated serum IgG levels (35.1 +/- 14.1 g/l; 29.2 +/- 13.9 g/l respectively; control values 20 +/- 5.9 g/l p < 0.05 for comparison with both experimental groups). Intrinsic lymphocyte proliferation to T and B cell mitogens was markedly depressed in the portacaval anastamosed rats when compared to controls. Serum factors inhibitory to control lymphocyte proliferation were noted in the shunted rats. Phagocytosis of complement and immunoglobulin sensitised sheep RBC by Kupffer cells purified from rats that had undergone portacaval shunting was markedly reduced (p < 0.05). The increased degree of phagocytosis following exposure to LPS-endotoxin (50 micrograms/ml) was proportionate in degree to the control group. Spontaneous release of bioactive lymphocyte activating factors (IL-1 and IL-6) by purified rat sinusoidal cell populations was decreased in the portacaval shunted group, and decreased still further following stimulation with LPS (50 micrograms/ml) in vitro. The observation that many of the haemostatic and immunological abnormalities associated with chronic liver disease are present in rats with surgically created portacaval shunts or with induced portal hypertension, lends credence to the hypothesis that shunting of portal blood is, at least in part, responsible for many of the systemic manifestations associated with chronic liver disease.

Characterization of peripheral blood lymphocytes in patients with non-cirrhotic portal fibrosis: a comparison with cirrhotics and healthy controls

Non-cirrhotic portal fibrosis (NCPF) is a common cause of portal hypertension in India. Its aetiopathogenesis is not well understood. To investigate the possibility of an immune mediated injury, phenotypes of peripheral blood lymphocytes were studied in 15 NCPF patients and were compared with an equal number of compensated cirrhotics and matched healthy controls. The population of total peripheral T lymphocytes (T1) and suppressor/cytotoxic phenotype (T8) was significantly (P less than 0.01) decreased in NCPF patients compared with controls. The sub-populations of helper/inducer lymphocytes (T4) and total B lymphocytes, however, were comparable with controls. The ratio of T4 to T8 lymphocytes was significantly (P less than 0.01) increased in NCPF patients in comparison with controls. Similar changes in the lymphocyte population were also observed in cirrhotic patients. Further investigations are required to identify whether the cellular alterations seen in NCPF have a pathogenetic basis or are secondary to the disease process itself.