Medical treatment of primary biliary cirrhosis and primary sclerosing cholangitis

The association of histological progression with biochemical response to ursodeoxycholic acid in primary biliary cholangitis

Primary biliary cholangitis (PBC) is currently diagnosed at an early stage; therefore, the number of patients with PBC without symptoms at the time of diagnosis is increasing. However, up to 30% of patients with PBC exhibit the suboptimal response to ursodeoxycholic acid (UDCA) and are at high risk of end-stage liver disease. Obeticholic acid is an approved second-line therapy for patients with PBC that are refractory to UDCA. Novel surrogate endpoints are required to identify individuals eligible for second-line therapies. An inadequate biochemical response to UDCA is a useful predictor of poor outcomes in patients with PBC. In addition to UDCA effects on biochemical parameters, histological outcomes could be considered as candidate surrogate endpoints. Alterations in liver histology are used as surrogate endpoints in clinical studies. However, current staging systems are insufficient to determine PBC disease severity and progression because of the pathological heterogeneity of the disease. Histological features at baseline and biochemical response to UDCA treatment can affect the disease course of PBC. Therefore, novel surrogate endpoints must be represented by parameters characterized by histological outcomes and treatment responses in PBC. In this review, we discuss the existing histological parameters and newly created factors to identify patients with PBC who are at a high risk of developing end-stage liver disease and, consequently, the potential need for additional treatments.

Identification of clinical risk factors for histological progression of primary biliary cholangitis

AIM

To identify laboratory predictors of histological progression (HP) of primary biliary cholangitis (PBC).

METHODS

Sequential biopsies were carried out on 35 (11.4%) of 308 patients with PBC treated with ursodeoxycholic acid (UDCA). Patients were divided into high γ-glutamyl transpeptidase (GGT) (n = 18) and low GGT (n = 17) groups, based on the median value of GGT at baseline. Patients were then categorized as showing HP (progressive group, PG) or lacking HP (non-progressive group, NPG) according to the Scheuer and Nakanuma classifications, with the latter grading liver fibrosis (fibrosis score) and bile duct loss (BDL score).

RESULTS

According to the Scheuer definition, 12 patients had HP and 23 did not. According to the Nakanuma definition, 8 and 27 patients were in the PG and NPG groups, respectively. The fibrosis and BDL scores progressed in 13 and 8 patients, respectively, whereas 22 and 25 patients did not show HP, respectively. Fisher's exact probability test analysis revealed that the rate of HP using the Nakanuma fibrosis score was significantly higher in the high GGT group compared to the low GGT group (P < 0.05). However, no significant correlation was found between the HP of PBC and the biochemical response to UDCA therapy. Both univariate and multivariate logistic regression analyses indicated that the serum GGT level at baseline is an independent risk factor for an increased Nakanuma fibrosis score.

CONCLUSIONS

The level of serum GGT at baseline is significantly associated with liver fibrosis progression in PBC, and therefore could help to predict the HP of PBC.

Primary biliary cirrhosis

Primary biliary cirrhosis is a chronic liver disease characterised by intrahepatic bile-duct destruction, cholestasis, and, in some cases, cirrhosis. Evidence supporting the autoimmune nature of this disorder includes the appearance of highly specific antimitochondrial antibodies (AMAs) and autoreactive T cells. Concordance rates in monozygotic twins, familial prevalence, and genetic associations underscore the importance of genetic factors, whereas findings of epidemiological studies and murine models suggest a possible role for exogenous chemicals and infectious agents through molecular mimicry. The incidence of primary biliary cirrhosis has increased over recent decades, possibly attributable to augmented testing of liver biochemistry rather than a rise in disease incidence. AMAs remain the hallmark of diagnosis in most cases and allow detection of asymptomatic patients. Symptomatic individuals usually present with either pruritus or fatigue and, more rarely, with either jaundice or complications of cirrhosis. The prognosis of primary biliary cirrhosis has improved because of early diagnosis and use of ursodeoxycholic acid, the only established medical treatment for this disorder. Although not a cure, treatment can slow disease progression and delay the need for liver transplantation. However, some patients do not respond adequately to ursodeoxycholic acid and might need alternative therapeutic approaches.

Successful low-dose azathioprine for myasthenia gravis despite hepatopathy from primary sclerosing cholangitis: a case report

INTRODUCTION

Although myasthenia gravis is frequently associated with other disorders, it has not been reported together with primary sclerosing cholangitis, complicating the administration of liver-toxic immunosuppressive therapy.

CASE PRESENTATION

A 73-year-old Caucasian woman with a history of arterial hypertension, thyroid dysfunction, glaucoma, right-sided ptosis and later generalized weakness, was diagnosed with myasthenia gravis. Additionally, primary sclerosing cholangitis was detected, initially prohibiting the administration of immunosuppressants. Despite treatment with steroids and pyridostigmine she repeatedly experienced myasthenic crises. After the fifth crisis and after antibody titers had reached levels > 100 nmol/L during two years of follow-up, it was decided to restart azathioprine. Interestingly, low-dose azathioprine (1.5 mg/kg/day) was well tolerated, had a positive clinical and immunological effect and did not worsen primary sclerosing cholangitis.

CONCLUSION

Myasthenia gravis may occur together with primary sclerosing cholangitis in the same patient. Mild immunosuppression with azathioprine is feasible and effective in such a patient, without worsening myasthenia gravis or primary sclerosing cholangitis.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease with a slowly progressive course. Without treatment, most patients eventually develop fibrosis and cirrhosis of the liver and may need liver transplantation in the late stage of disease. PBC primarily affects women (female preponderance 9–10:1) with a prevalence of up to 1 in 1,000 women over 40 years of age. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The diagnosis is based on sustained elevation of serum markers of cholestasis, i.e., alkaline phosphatase and gamma-glutamyl transferase, and the presence of serum antimitochondrial antibodies directed against the E2 subunit of the pyruvate dehydrogenase complex. Histologically, PBC is characterized by florid bile duct lesions with damage to biliary epithelial cells, an often dense portal inflammatory infiltrate and progressive loss of small intrahepatic bile ducts. Although the insight into pathogenetic aspects of PBC has grown enormously during the recent decade and numerous genetic, environmental, and infectious factors have been disclosed which may contribute to the development of PBC, the precise pathogenesis remains enigmatic. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at adequate doses of 13–15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. The mode of action of UDCA is still under discussion, but stimulation of impaired hepatocellular and cholangiocellular secretion, detoxification of bile, and antiapoptotic effects may represent key mechanisms. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarizes current knowledge on the clinical, diagnostic, pathogenetic, and therapeutic aspects of PBC.

Combination of ursodeoxycholic acid and glucocorticoids upregulates the AE2 alternate promoter in human liver cells

Primary biliary cirrhosis (PBC) is a cholestatic disease associated with autoimmune phenomena and alterations in both biliary bicarbonate excretion and expression of the bicarbonate carrier AE2. The bile acid ursodeoxycholic acid (UCDA) is currently used in treatment of cholestatic liver diseases and is the treatment of choice in PBC; however, a subset of PBC patients respond poorly to UDCA monotherapy. In these patients, a combination of UDCA and glucocorticoid therapy appears to be beneficial. To address the mechanism of this benefit, we analyzed the effects of UDCA and dexamethasone on AE2 gene expression in human liver cells from hepatocyte and cholangiocyte lineages. The combination of UDCA and dexamethasone, but not UDCA or dexamethasone alone, increased the expression of liver-enriched alternative mRNA isoforms AE2b1 and AE2b2 and enhanced AE2 activity. Similar effects were obtained after replacing UDCA with UDCA conjugates. In in vitro and in vivo reporter assays, we found that a UDCA/dexamethasone combination upregulated human AE2 alternate overlapping promoter sequences from which AE2b1 and AE2b2 are expressed. In chromatin immunoprecipitation assays, we demonstrated that combination UCDA/dexamethasone treatment induced p300-related interactions between HNF1 and glucocorticoid receptor on the AE2 alternate promoter. Our data provide a potential molecular explanation for the beneficial effects of the combination of UDCA and glucocorticoids in PBC patients with inadequate response to UDCA monotherapy.

Medical treatment of cholestatic liver disease

In most cholestatic liver diseases the cause of the disease is not known and therapy can only be directed toward suppression of the pathogenetic processes and amelioration of the consequences of cholestasis. The recognition of adaptive-compensatory responses to cholestasis has become of major importance. They tend to minimize retention of bile acids and other potentially toxic solutes in the hepatocyte by limiting hepatocellular uptake, reducing bile acid synthesis, stimulating detoxification, and up-regulating alternative pathways for excretion. Some of the drugs used for the treatment of cholestatic liver diseases in an empiric way turned out to be modulators of nuclear receptors, which regulate these adaptive-compensatory responses. New drugs are being designed and tested along these lines and may be regarded as treatment opportunities of the future.

Medical treatment of primary biliary cirrhosis and primary sclerosing cholangitis

Chronic cholestasis is the main feature of primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), the most common chronic cholestatic liver diseases in adults. Although the etiology of both diseases remains poorly understood, auto-immune processes appear to be important, particularly in PBC. PBC and PSC usually slowly progress to cirrhosis,liver failure, and death, unless liver transplantation is performed. Ursodeoxycholic acid(UDCA), a hydrophilic dihydroxy bile acid, is the only drug currently approved for the treatment of patients with PBC and is also used in patients with PSC. In addition to UDCA, patients with PSC should be referred to endoscopic dilatation of major bile duct stenoses. Several potential mechanisms of action of UDCA have been proposed, including intracellular modulation of signaling events and secretion. Various immunosuppressive drugs have been evaluated alone or in combination with UDCA-especially for the treatment of PBC. Of these drugs,the topical corticosteroid budesonide, together with UDCA, appears promising in the treatment of early stage PBC, but data remain insufficient to warrant use of budesonide outside of controlled studies.

Treatment of Biliary Problems in Inflammatory Bowel Disease

The most common biliary problem in patients with inflammatory bowel disease is primary sclerosing cholangitis (PSC). The treatment of this disease is multifaceted and frequently requires a multidisciplinary approach involving internists, nutritionists, gastroenterologists, and surgeons. Unfortunately, other than liver transplantation, no therapy that is currently available has been proven to alter the natural history of PSC or prolong survival. Ursodeoxycholic acid is currently the most promising pharmacologic treatment option for slowing disease progression and should be used in higher than usual doses (20 to 30 mg/kg/d). Treatment of symptoms due to cholestasis, such as pruritis and steatorrhea, is an important aspect of the medical care of patients with PSC. Our preferred treatment of pruritis due to cholestasis is with bile acid binding exchange resins such as cholestyramine or colestipol (which is generally better tolerated than cholestyramine). Endoscopic therapy should be reserved for patients with obstructive jaundice, cholangitis, or symptomatic dominant biliary strictures. We recommend dilation of dominant strictures with graduated or balloon dilators followed by temporary stenting if the postdilation cholangiographic appearance is not improved or adequate biliary drainage cannot be assured. There is indirect evidence that the combination of ursodeoxycholic acid and endoscopic therapy to maintain biliary patency may improve transplant-free survival in patients with PSC, although this remains to be proven. Liver transplantation remains the only effective treatment of advanced PSC, and should be considered in patients with complications of cirrhosis or intractable pruritis or fatigue.