Pathogenesis and management of pruritus in cholestatic liver disease

Patients with cholestatic liver diseases such as primary biliary cirrhosis, primary sclerosing cholangitis and intrahepatic cholestasis of pregnancy commonly complain of pruritus. The underlying pathogenesis remains obscure with several mediators possibly playing an important role; these include lysophosphatidic acid, bile salts, opioids, histamine and progesterone metabolites. We describe in this review novel insights into the pathogenesis and management of pruritus in patients with cholestasis.     

Atypical causes of cholestasis

Cholestatic liver disease consists of a variety of disorders. Primary sclerosing cholangitis and primary biliary cirrhosis are the most commonly recognized cholestatic liver disease in the adult population, while biliary atresia and Alagille syndrome are commonly recognized in the pediatric population. In infants, the causes are usually congenital or inherited. Even though jaundice is a hallmark of cholestasis, it is not always seen in adult patients with chronic liver disease. Patients can have “silent” progressive cholestatic liver disease for years prior to development of symptoms such as jaundice and pruritus. In this review, we will discuss some of the atypical causes of cholestatic liver disease such as benign recurrent intrahepatic cholestasis, progressive familial intrahepatic cholestasis, Alagille Syndrome, biliary atresia, total parenteral nutrition induced cholestasis and cholestasis secondary to drug induced liver injury.     

Sclerosing Cholangitis: Pediatric Perspective

Sclerosing cholangitis is a rare progressive cholestatic liver disease affecting the biliary tract. It may be associated with other diseases including autoimmune hepatitis, immunodeficiencies, cystic fibrosis, and sickle cell disease. Sclerosing cholangitis not associated with other diseases is termed “primary sclerosing cholangitis,” which has a strong association with male gender, Caucasian race, and inflammatory bowel disease. Diagnosis is based on typical biochemical, radiologic, and histologic features. Medical management is directed mainly at managing complications (pruritus, cholangitis, strictures, and nutritional deficiencies). Administration of ursodeoxycholic acid results in biochemical improvement, but has not been proven to prolong transplant-free survival. Patients with autoimmune overlap respond to immunosuppression. The disease is typically progressive and evolves to biliary cirrhosis and possibly cholangiocarcinoma. Orthotopic liver transplantation remains the only life-extending alternative for patients with sclerosing cholangitis, with good long-term patient and graft survival, and recurrent graft primary sclerosing cholangitis in about 10% of children.     

Latest and Emerging Therapies for Primary Biliary Cirrhosis and Primary Sclerosing Cholangitis

Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are the two most common causes of chronic cholestatic liver disease in adults. In PBC, therapy with ursodeoxycholic acid (UDCA) is safe and has been associated with tangible biochemical, histologic, and survival benefits. However, a need for different or adjuvant therapies remains for specific subsets of PBC patients, including those who do not respond to UDCA and those who have advanced histologic disease at presentation. Similarly, beneficial therapies for disease-related symptoms that do not typically respond to UDCA (eg, fatigue and pruritus) are still needed. In contrast to PBC, no medical therapy of proven benefit has been identified for patients with PSC. In PBC and PSC, adequate management of complications of chronic cholestasis is important. For both diseases, liver transplantation is the only curative option.     

Pathophysiology and current management of pruritus in liver disease

Pruritus is frequently reported by patients with cholestatic hepatobiliary diseases such as primary biliary cirrhosis, primary sclerosing cholangitis, intrahepatic cholestasis of pregnancy and hereditary cholestatic syndromes, but may accompany almost any other liver disease. Increased concentrations of bile salts, histamine, progesterone metabolites or endogenous opioids have been controversially discussed as potential pruritogens in cholestasis in the past. Most recently, novel insights unravelled lysophosphatidic acid (LPA), a potent neuronal activator, as a potential pruritogen in pruritus of cholestasis. Nevertheless, the pathogenesis of pruritus in cholestasis is still not clearly defined and current antipruritic treatment strategies provide relief only in a part of the affected patients. Based on recent experimental and clinical findings, this review outlines the actual insight in pathogenesis of pruritus in cholestasis and summarizes evidence-based and experimental therapeutic interventions for cholestatic patients suffering from itch.     

Recent advances in the management of pruritus in chronic liver diseases

Pruritus is a symptom found in patients with chronic liver diseases,especially cholestatic liver diseases such as primary biliary cholangitis.This symptom impairs patient quality of life by disturbing sleep and may lead to consideration of liver transplantation.Mechanisms implicated in pruritus have been associated with the peripheral and central nervous systems,leading to the development of various therapeutic options.Little evidence for the efficacy of most of these treatments is currently available,indicating a need for further investigations.     

The Overlap Syndromes of Autoimmune Hepatitis

Autoimmune hepatitis has two major variant phenotypes in which the features of classical disease are co-mingled with those of primary biliary cirrhosis or primary sclerosing cholangitis. These overlap syndromes lack codified diagnostic criteria, established pathogenic mechanisms, and confident management strategies. Their clinical importance relates mainly to the identification of patients who respond poorly to conventional corticosteroid treatment. Scoring systems that lack discriminative power have been used in their definition, and a clinical phenotype based on pre-defined laboratory and histological findings has not been promulgated. The frequency of overlap with primary biliary cirrhosis is 7–13 %, and the frequency of overlap with primary sclerosing cholangitis is 8–17 %. Patients with autoimmune hepatitis and features of cholestatic disease must be distinguished from patients with cholestatic disease and features of autoimmune hepatitis. Variants of the overlap syndromes include patients with small duct primary sclerosing cholangitis, antimitochondrial antibody-negative primary biliary cirrhosis, autoimmune sclerosing cholangitis, and immunoglobulin G4-associated disease. Conventional corticosteroid therapy alone or in conjunction with ursodeoxycholic acid (13–15 mg/kg daily) has been variably effective, and cyclosporine, mycophenolate mofetil, and budesonide have been beneficial in selected patients. The key cholestatic features that influence the prognosis of autoimmune hepatitis must be defined and incorporated into the definition of the syndrome rather than rely on designations that imply the co-mingling of different diseases with manifestations of variable clinical relevance. The overlap syndromes in autoimmune hepatitis are imprecise, heterogeneous, and unfounded, but they constitute a clinical reality that must be accepted, diagnosed, refined, treated, and studied.     

原发性胆汁性胆管炎相关瘙痒症的管理

原发性胆汁性胆管炎(PBC)是一种进行性肝内胆汁淤积性自身免疫性疾病,瘙痒可见于60%~70%的PBC患者,并严重影响患者的生活质量。改善PBC患者的瘙痒症状对提高患者的生活质量有着重要意义。主要总结了PBC的发病机制、PBC相关瘙痒症的治疗进展。     

Metabolomic profiling of 17 bile acids in serum from patients with primary biliary cirrhosis and primary sclerosing cholangitis: a pilot study

BackgroundPrimary biliary cirrhosis and primary sclerosing cholangitis are two cholestatic diseases characterised by hepatic accumulation of bile acids.AimsThis study compares serum bile acid levels in patients with primary biliary cirrhosis and primary sclerosing cholangitis and from age and sex-matched non cholestatic donors.MethodsSeventeen bile acids were quantified using liquid chromatography coupled to tandem mass spectrometry. Serum samples from cholestatic patients were compared with those of non-cholestatic donors.ResultsThe concentration of total bile acids, taurine and glycine conjugates of primary bile acids was elevated in both patients with primary biliary cirrhosis and primary sclerosing cholangitis when compared to non-cholestatic donors. Samples from primary sclerosing cholangitis patients displayed reduced levels of secondary acids, when compared to non cholestatic and primary biliary cirrhosis sera. The ratio of total glycine versus total taurine conjugates was reduced in patients with primary biliary cirrhosis, but not in primary sclerosing cholangitis.ConclusionThe present study suggests that circulating bile acids are altered differentially in primary biliary cirrhosis and primary sclerosing cholangitis patients.     

Granulomas in primary sclerosing cholangitis

Abstract: Granulomas in liver biopsy specimens from adult patients with chronic ductopenic cholestatic liver disease are a characteristic feature of primary biliary cirrhosis. However, we found a similar combination of abnormalities in 7 out of 100 native livers (7%) from patients who had orthotopic liver transplantation for primary sclerosing cholangitis. In a control group of native livers from 100 patients with primary biliary cirrhosis, the prevalence of granulomas was exactly the same, 7%. In the primary sclerosing cholangitis group, 13 additional livers showed a granulomatous epithelioid cell response, with or without foreign body type giant cells, to extravasated bile. All granulomas were noncaseating and non-necrotizing; they consisted of epithelioid cells and often contained giant cells. Perigranulomatous lymphocytic infiltrates were generally mild to moderate. The granulomas involved portal tracts, scars, and hepatic parenchyma. Biopsy experience revealed that granulomas can be found in all stages of the disease. In contradistinction to the granulomas in primary biliary cirrhosis, the granulomas in primary sclerosing cholangitis did not represent granulomatous cholangitis – that is, they were not a feature of the duct destruction. The etiology of these lesions is not clear, but in some cases we found strong morphologic evidence that granulomas may form as a response to the leakage of bile or bile components. No evidence of infection or of sarcoidosis was found. Although adverse drug responses cannot be ruled out with certainty, review of the clinical histories made that mechanism unlikely. Thus, the presence of granulomas in chronic ductopenic cholestatic liver disease is not pathognomonic for primary biliary cirrhosis and, in rare instances (on average, in 3–4% of the biopsy samples), may be a feature of primary sclerosing cholangitis.     

胆汁淤积性肝病并发皮肤瘙痒的发病机制及治疗进展

瘙痒是胆汁淤积性肝病如原发性胆汁性肝硬化、原发性硬化性胆管炎和妊娠期肝内胆汁淤积症的一个常见症状。既往研究的胆汁淤积性瘙痒的潜在致痒因子有胆盐、组胺、孕酮代谢产物、内源性阿片样物质和溶血性磷脂酸等。然而,胆汁淤积性瘙痒的确切发病机制尚不清楚,现有的止痒方法仅可使部分患者症状得到缓解,新的止痒方法已被提出和(或)正在研究中。在回顾近期关于胆汁淤积型肝病并发皮肤瘙痒的发病机制和治疗的实验和临床试验,以便提高对胆汁淤积性瘙痒的认识和治疗。     

Sertraline as a first-line treatment for cholestatic pruritus

Pruritus is frequently the most debilitating symptom of cholestatic liver diseases. Moreover, existing therapies are often ineffective. Recent small, retrospective case series reports suggest that serotonin reuptake inhibitors can improve pruritus. This study was undertaken to establish the dose of sertraline and to evaluate its efficacy for cholestatic pruritus. Twenty one subjects with chronic pruritus due to liver disease (including primary biliary cirrhosis, primary sclerosing cholangitis, chronic hepatitis C, and postnecrotic cirrhosis) initially underwent an open-label, dose escalation to determine the dose with optimal efficacy and tolerability. After a washout period, 12 of the subjects entered a randomized, double-blind, placebo-controlled trial. Participants quantified their pruritus using a 0-10 visual analog scale, and pruritus was assessed for distribution, timing, degree of disability, and physical evidence of scratching. The optimum sertraline dose (75-100 mg/day) was well tolerated. In the controlled portion of the study, itch scores improved in patients taking sertraline, but worsened in patients taking placebo (P=0.009). Changes in itch distribution, duration, direction, and physical evidence of scratching paralleled changes in the visual analog pruritus score. CONCLUSION: Sertraline seems to be an effective, well-tolerated treatment for pruritus due to chronic liver disease. These results suggest that serotonergic pathways are important in the perception of itch.     

Medical treatment of primary biliary cirrhosis and primary sclerosing cholangitis.

Treatment of primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) with ursodeoxycholic acid (UDCA) has been in common use since 1985. In PBC, treatment with UDCA improves laboratory data, liver histology, enables a longer transplantation-free interval and prolongs disease survival. Because UDCA is unable to cure the disease newer drugs or combination therapies are still needed. Studies with UDCA and immunosuppressants such as prednisone, budesonide and azathioprine have shown that in selected patients combination therapy may be superior to UDCA monotherapy. PSC is treated successfully with UDCA and endoscopic dilatation of the bile duct strictures. Treatment of extrahepatic manifestations of cholestatic liver disease such as pruritus, fatigue, osteoporosis and steatorrhea can be problematic and time-consuming.     

Liver transplantation for cholestatic liver disease

Opinion statement Liver transplantation is an effective form of therapy for patients with end-stage cholestatic disease that improves both survival and quality of life. Liver transplantation is very effective for the treatment of intractable pruritus but less effective for the treatment of lethargy. Survival rates are good (more than 70% at 5 years); these patients are at greater risk of developing acute and chronic rejection and are more likely to require long-term immunosuppression. Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) recur in the graft. Recurrent PSC may be difficult to differentiate from secondary sclerosing cholangitis, but it recurs in up to 60% of patients at 5 years and may reduce graft survival. PBC recurrence, noted in up to 40% of patients at 10 years, has little effect on graft survival with respect to cancers. Patients with PSC are at greater risk of both colonic cancer (which may be reduced by ursodeoxycholic acid) and cholangiocarcinoma. Diagnosis of cholangiocarcinoma before transplantation usually contraindicates transplantation. The main challenges facing liver transplantation are the need to expand the donor pool and the need to find immunosuppressive regimens with fewer long-term toxicities.     

Sequential changes in serum levels of individual bile acids in patients with chronic cholestatic liver disease

In order to determine the value of serum bile acids in predicting the course of chronic cholestatic liver diseases, we measured individual serum bile acids serially, using high-performance liquid chromatography, over a 4 year observation period in 12 patients with primary biliary cirrhosis and six patients with primary sclerosing cholangitis. The changes in individual serum bile acids and the ratios thereof, conventional liver tests and Child-Turcotte and Mayo scores were compared between survivors (n= 10) and patients who underwent liver transplantation for (n= 3) or died of the liver disease (n= 5). Patients with a serum total chenodeoxycholic acid concentration at study entry that exceded 15 μmol/L were 10 times more likely to die or need a liver transplant in the following 4 years than those with chenodeoxycholic acid levels < 15 μmol/L (P < 0.05). None of the other biochemical parameters or clinicopathological scores could similarly discriminate between the two groups at entry. Time-dependent analyses for the cholic acid/chenodeoxycholic acid ratio, serum total bilirubin and albumin concentrations and Child-Turcotte and Mayo scores were able to differentiate between primary sclerosing cholangitis patients who died or were transplanted and those who were not, whereas age of the patients and other parameters did not. The taurocholic acid /taurochenodeoxycholic acid ratio fell during progression of primary biliary cirrhosis but rose in temporal relationship with primary sclerosing cholangitis. This differential pattern of change was unique compared with other clinical and laboratory indices. In conclusion, serum chenodeoxycholic acid levels and the cholic acid /chenodeoxycholic acid ratio in both diseases were independent indices that allowed for the prediction of survival or the need for liver transplantation. These indices are worthy of further examination in a larger group of patients as prognostic criteria for chronic cholestatic liver disease and in the assessment of the efficacy of therapeutic interventions, including liver transplantation.     

Primary sclerosing cholangitis: diagnostic and therapeutic problems

Progressive destruction of bile ducts in primary sclerosing cholangitis (PSC) may lead to end-stage liver disease, portal hypertension and liver failure. The diagnosis of PSC is made by characteristic multifocal stricturing and dilation of intrahepatic and/or extrahepatic bile ducts observed by cholangiography. Magnetic resonance cholangiography is considered to have comparable accuracy to endoscopic retrograde cholangiography (ERC) in the diagnosis of PSC, but its accuracy is limited in early stages of PSC. Up to 60% of patients with PSC develop a dominant stricture of the intra- or extrahepatic biliary tree. Patients may present with jaundice, pruritus or ascending cholangitis. Therefore, in patients with an increase in serum bilirubin and/or worsening pruritus, progressive bile duct dilation on imaging studies and/or cholangitis seen via ERC, it is recommended to exclude a dominant stricture. However, in a considerable number of patients without symptoms, a dominant stricture can be detected on the cholangiogram. The cholangiographic findings and the clinical presentation make it difficult to distinguish PSC from cholangiocarcinoma. The accuracy in the distinction between these two conditions is still rather disappointing, despite the combined use of imaging, endoscopic biopsy, and cytology. Medical, endoscopic, and surgical therapies aim to slow the progression of the disease. It is generally agreed upon that patients with symptoms from dominant strictures like cholangitis, jaundice, pruritus or worsening biochemical indices are candidates for endoscopic therapy. Although the best therapeutic endoscopic approach for these patients is still under discussion, a number of reports have documented clinical and radiographic improvement in patients following endoscopic dilation with or without placement of a biliary stent. Furthermore, indirect evidence by retrospective studies suggests that endoscopic therapy may improve survival.     

Old and new treatments for primary biliary cholangitis

Primary biliary cholangitis (formerly primary biliary cirrhosis) is a rare progressive cholestatic liver disease, whose hallmark features include a persistently elevated alkaline phosphatase level, presence of anti‐mitochondrial antibodies and characteristic histology. Since 1998, ursodeoxycholic acid (UDCA), a bile acid, has been the only available therapeutic agent. Primary biliary cholangitis is associated with the development of end‐stage liver disease, increased morbidity and mortality. UDCA has been shown to improve serum biochemistries, histology and delay the need for liver transplantation. The clinical issue is that approximately 25%‐40% of patients do not respond to this standard therapy. In recent years, many trials have investigated alternative and adjunctive treatments, leading to the recent approval of obeticholic acid, an analogue of chenodeoxycholic acid, which has shown significant and sustained reductions in alkaline phosphatase levels in combination with UDCA. Obeticholic acid has rapidly been embraced as a new agent to improve the biochemical profile in refractory patients, in addition to being approved for use as monotherapy in patients who cannot tolerate UDCA. There are several other studies and targets which are being investigated. This review is intended to highlight the benefits of UDCA, educate the reader on the newly available obeticholic acid, and to summarize the many ongoing trials and therapeutic targets being investigated in attempts to control and cure primary biliary cholangitis.     

Primary and secondary autoimmunity in hepatology

Primary autoimmune liver diseases can be hepatitic or cholestatic in nature. Autoimmune hepatitis, more often diagnosed in women, is characterized by biochemical and histological activity, with polyclonal hypergammaglobulinemia as a frequent feature. Antinuclear and anti-smooth muscle antibodies are the serological hallmarks of type 1 autoimmune hepatitis, whereas liver-kidney microsomal antibody type 1 and liver cytosol antibody type 1 designate the type 2 form. Response to immunosuppression is usually excellent. The most frequent cholestatic autoimmune disease is primary biliary cirrhosis, characterized by anti-mitochondrial antibody positivity and typical bile duct lesions observed on liver biopsy. Treatment with biliary acids improves the biochemical picture, may alleviate pruritus, and delays the development of end-stage liver disease. Primary sclerosing cholangitis occurs more frequently in men and affects both the intra- and extrahepatic biliary trees, determining the typical "beading" appearance. Associated inflammatory bowel diseases are often observed. To date, no medical therapy is able to modify the course of this disease. Autoimmune cholangitis is an anti-mitochondrial antibody-negative cholestatic disease with most of the features of primary biliary cirrhosis. "Overlap" syndromes where autoimmune hepatitic and cholestatic features coexist in the same patient, have also been reported. Autoimmune phenomena secondary to hepatitis C virus-related liver disease such as the occurrence of antinuclear, anti-smooth muscle antibodies and liver-kidney microsomal antibody type 1 are often observed.     

Endoscopy in the management of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic, cholestatic liver condition characterized by progressive fibrosis and destruction of the intra-and extrahepatic biliary tree. PSC has a clear association with inflammatory bowel disease and is often progressive, leading to cirrhosis and end-stage liver failure. For many patients, liver transplantation offers the only hope of long-term survival. No effective medical treatment exists, and therapy is often aimed at treating complications of the disorder, including dominant biliary strictures, which may cause symptomatic jaundice, cholangitis, and pruritus. Studies on endoscopic therapy (eg, biliary dilation and/or stent insertion) have shown favorable results, although most studies have been small, retrospective, and uncontrolled. Up to 20% of patients with PSC develop cholangiocarcinoma; however, distinguishing between cholangiocarcinoma and benign strictures can be difficult. Ideally, randomized trials are required to determine the safest and most effective endoscopic management for symptomatic dominant strictures.     

Death receptor 5 mediated-apoptosis contributes to cholestatic liver disease

Chronic cholestasis often results in premature death from liver failure with fibrosis; however, the molecular mechanisms contributing to biliary cirrhosis are not demonstrated. In this article, we show that the death signal mediated by TNF-related apoptosis-inducing ligand (TRAIL) receptor 2/death receptor 5 (DR5) may be a key regulator of cholestatic liver injury. Agonistic anti-DR5 monoclonal antibody treatment triggered cholangiocyte apoptosis, and subsequently induced cholangitis and cholestatic liver injury in a mouse strain-specific manner. TRAIL- or DR5-deficient mice were relatively resistant to common bile duct ligation-induced cholestasis, and common bile duct ligation augmented DR5 expression on cholangiocytes, sensitizing mice to DR5-mediated cholangitis. Notably, anti-DR5 monoclonal antibody-induced cholangitis exhibited the typical histological appearance, reminiscent of human primary sclerosing cholangitis. Human cholangiocytes constitutively expressed DR5, and TRAIL expression and apoptosis were significantly elevated in cholangiocytes of human primary sclerosing cholangitis and primary biliary cirrhosis patients. Thus, TRAIL/DR5-mediated apoptosis may substantially contribute to chronic cholestatic disease, particularly primary sclerosing cholangitis.