The molecular mechanism of cholestatic pruritus

Pruritus is a frequent symptom in patients with cholestatic liver diseases. Pruritus can be excruciating and, in rare cases, become a primary indication for liver transplantation. The molecular mechanism of itch signal transduction is largely unclear. It was our hypothesis that compounds which accumulate in the circulation during cholestasis act as direct or indirect pruritogens by affecting signaling in itch fibers. To test this, we screened plasma samples of a large group of patients with various cholestatic conditions for their capacity to activate neuroblastoma cells. Quite strikingly, we found that samples from itchy cholestatic patients caused a significantly higher activation than samples from non-itchy cholestatic patients and healthy controls. Purification revealed lysophosphatidic acid (LPA) as the active compound. LPA is a very potent signaling lipid that can activate cells through various LPA receptors. Subsequently, we could demonstrate that cholestatic patients with pruritus have highly elevated levels of serum autotaxin (ATX), the enzyme that converts lysophosphatidylcholine into LPA. This is a striking finding as ATX has never been connected to itch perception thus far. We have also shown that LPA, when injected intradermally, causes itching in mice. On the basis of our results, we hypothesize that during cholestasis, expression of ATX is induced and gives rise to increased local formation of LPA near unmyelinated nerve endings of itch fibers. LPA then activates these neurons through one of the LPA receptors, which in turn potentiates action potentials along itch fibers.     

Primary biliary cirrhosis in HBV and HCV patients: Clinical characteristics and outcome

AIM: To present the characteristics, management and outcome of patients with hepatitis B virus (HBV) or hepatitis C virus (HCV) infections concurrent with primary biliary cirrhosis (PBC).METHODS: Since January 2001 to September 2009, we retrospectively evaluated the medical records of all HBV (n = 1493) and HCV patients (n = 526) who are followed in our center for the presence of concurrent PBC. Seventeen patients identified with concurrent viral hepatitis and PBC (8 HCV and PBC; follow-up: 61 ± 37 mo and 9 HBV and PBC; follow-up: 57 ± 38 mo). PBC diagnosis was established if the patients met at least two of the following criteria: positivity for antimitochondrial antibody, elevated cholestatic enzymes and histological lesions of PBC.RESULTS: HCV or HBV diagnosis preceded that of PBC in most patients by many years. PBC diagnosis was based on the presence of antimitochondrial antibody and elevated cholestatic enzymes in all 17 patients, while one third (5/17; 29.4%) experienced severe pruritus many years before diagnosis. Patients with PBC and HBV were significantly younger at diagnosis of PBC compared to patients with PBC and HCV (56.1 ± 11.2 vs 68.5 ± 10.3, respectively, P < 0.05). At initial clinical and histological assessment the majority of patients were cirrhotics (10/17; 58.8%) with the group of PBC and HCV carrying the highest frequency (87.5% vs 33.3% in PBC and HBV; P < 0.05). The patients with HBV and concomitant PBC seem to have better outcome compared to those with HCV and PBC since none of the 6 non-cirrhotics with HBV and PBC developed cirrhosis during follow-up.CONCLUSION: PBC diagnosis in HBV or HCV patients is very difficult and usually delayed. Therefore, in any case, cholestasis should alert physicians to further search for PBC.     

Successful use of the Molecular Adsorbent Recirculating System (MARS) in a patient with primary biliary cirrhosis (PBC) and treatment refractory pruritus

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease often associated with severe pruritus. Despite maximal medical management pruritus often persists and has a detrimental effect on quality of life. For patients that are refractory to all medical treatments, more invasive approaches have been tried. Recently, a new extracorporeal hemodiafiltration method, Molecular Adsorbent Recirculating System (MARS), has been described. Based on the hypothesis that hydrophobic, protein-bound metabolites play a major role in the development of liver failure, this device uses an albumin enriched dialysate to facilitate the removal of albumin bound toxins. Aim: To assess the safety and efficacy of a single MARS treatment on the pruritus score in a patient with PBC and treatment refractory pruritus. Design/Patients: A 61-year-old female patient with biopsy proven PBC, who had been accepted on our liver transplantation waiting list because of treatment refractory pruritus, was subjected to a single MARS treatment. Results: At the end of a single 8 h MARS treatment session pruritus completely disappeared. Not unexpectedly, however, this effect was only short lived. Except for a slight hypercalcemia no adverse events were observed. Conclusion: A single MARS treatment very effectively improved pruritus. Long-term repetitive treatment, however, might be necessary to sustain its effectiveness.     

不同方案治疗原发性胆汁性肝硬化合并干燥综合征的临床研究

 目的 观察不同方案治疗原发性胆汁性肝硬化（PBC）合并干燥综合征（SS）的疗效。方法 选PBC合并SS患者79例,分为3组:单用熊去氧胆酸组（U组,29例）、熊去氧胆酸+泼尼松龙组（UP组,37例）、熊去氧胆酸+硫唑嘌呤组（UA组,13例）,观察不同治疗方案的疗效。 结果3种方案对PBC合并SS患者的乏力、瘙痒均有明显改善,但组间比较差异无统计学意义（P值均＞0.05）;3种方案治疗后ALT、AST、碱性磷酸酶（ALP）、γ-谷氨酰转移酶、TBil、DBil、IgG、IgM均有明显下降,组内比较差异有统计学意义（P值均＜0.05）,但组间比较差异无统计学意义（P值均＞0.05）。结论 PBC合并SS以肝脏受累为主要表现时应以治疗PBC为主,熊去氧胆酸联合糖皮质激素或硫唑嘌呤治疗未发现优于单用熊去氧胆酸。     

Pruritus ani

PURPOSE: The aim of this study was to determine how frequently pruritus ani (PA) is a symptom secondary to benign or malignant colon and anorectal pathology. METHODS: One hundred nine patients with PA as the only presenting symptom were prospectively evaluated over a two-year period. All patients underwent anoscopy, rigid proctoscopy, and colonoscopy and were treated for PA. Patient data were entered into a computer data base and analyzed. RESULTS: The mean age was 52.1 years; males outnumbered females 2∶1. The mean duration of symptoms was 6.1 weeks. Mean coffee intake was four cups per day. Forty-five percent of patients smoked and 45 percent drank alcohol daily. Thirty-five percent had an abnormal proctosigmoidoscopy or colonoscopy. Twenty-seven (25 percent) patients had primary pruritus and 82 (75 percent) patients had coexisting colon or anorectal pathology. The PA-associated neoplasia included rectal cancer (11 percent), anal cancer (6 percent), adenomatous polyps (4 percent), and colon cancer (2 percent). Hemorrhoids (20 percent) and anal fissures (12 percent) were the most common pruritus-related anorectal diseases. Among the 23 percent of patients with PA and neoplasia, pruritic symptoms were present longer compared with those with PA and anorectal disease <0.001 and primary pruritus (P<0.0001).All patients with primary PA were initially treated with dietary fibers, steroid cream, and drying agents. The recurrence rate for primary pruritus was twice that for anorectal disease (P <0.0001). CONCLUSIONS: PA responds to treatment in 89 percent of patients, while 11 percent are refractory to treatment. Symptoms suggestive of pruritus ani, especially those of long duration, should alert the surgeon to the potential for proximal colon and anorectal neoplasia.     

Sensitivity and Specificity of Biochemical Tests for Diagnosis of Intrahepatic Cholestasis of Pregnancy

Background and aimIntrahepatic cholestasis of pregnancy (ICP) is linked with increased risk of fetal complications. An accurate diagnostic test is needed to diagnose this disorder on time. We aimed to assess sensitivity and specificity of laboratory tests used for diagnosis of intrahepatic cholestasis of pregnancy and determine more reliable cut-off values of transaminases.Material and methodsSixty one symptomatic patients with ICP and 29 healthy pregnant women were included in the retrospective analysis.ResultsICP patients had higher total bile acids (TBA) levels than healthy women (32 vs. 6; P < 0.0001) due to increase in cholic acid (CA) and chenodeoxycholic acid (CDCA). CA/CDCA ratio was significantly higher in ICP patients compared to healthy pregnant women (1.13 vs. 0.68; P < 0.00002). TBA, CA, CDCA and CA/CDCA ratio demonstrate the following sensitivity (94%, 96%, 89%, 71.9%) and specificity (63%, 63%, 59%, 79.3%, respectively) for ICP diagnosis. Lowering cut-off values for ALT (31 U/ L) and AST (30 U/L) resulted only in minimal increase of sensitivity to 92.2% vs. 90.1% for ALT and to 92.2%, vs. 90.6% for AST.ConclusionThe present study did not reveal any single specific and sensitive marker for reliable diagnosis of ICP. Establishment of lower cut-off values for transaminases activity might only minimally increase the accuracy of diagnosing ICP.     

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。     

The molecular adsorbent recirculating system as a liver support system. Summary of Mexican experience

Aim. The aim of this study was to assess the effects of the molecular absorbent recirculating system (MARS) on patients with acute liver failure (ALF) and liver failure with cirrhosis (AoCLF) as well as in cholestatic patients with intractable pruritus in a Mexican population.Material and methods. From August 2003 to December 2011, MARS was used in 38 patients with ALF, 15 patients with AoCLF, and 17 cholestatic patients with intractable pruritus. The patients were examined using a standard liver function test and for vital signs, presence of ascites and encephalopathy before and after each treatment. The therapeutic response, patient status, follow-up status, and need for liver transplantation were determined.Results. Seventy-nine MARS procedures were performed. MARS was used for ALF in 54.3% of patients, AoCLF in 24.2%, and cholestatic disease in 21.5%. There were significant improvements in serum bilirubin (p = 0.000), aspartate aminotransferase (p = 0.000), alanine aminotransferase (p = 0.030), gamma-glytamyl transpeptidase (p = 0.044), alkaline phosphatase (p = 0.006), and encephalopathy grade (p = 0.000). Thirty-eight ALF patients were listed for emergency liver transplantation and treated with MARS; 20 of these patients died on a waiting list, 18 survived. only four underwent liver transplantation and 14 (37%) recovered without transplantation after the MARS procedure.Conclusion. MARS is a safe and effective procedure, especially for ALF patients. Our results suggest that MARS therapy can contribute to native liver recovery in ALF patients.     

Differences between Caucasian, African American, and Hispanic patients with primary biliary cirrhosis in the United States

Primary biliary cirrhosis (PBC) is an uncommon chronic cholestatic liver disease that primarily afflicts young and middle-aged Caucasian women; there are limited data on the clinical presentation and disease severity among non-Caucasian patients with this disease. The goal of this study was to examine differences in the severity of liver disease between Caucasian and non-Caucasian patients with PBC screened for enrollment in a large national multicenter clinical trial. Demographic features, symptoms, physical findings, and laboratory tests obtained during screening were examined in 535 patients with PBC with respect to ethnicity, gender, and antimitochondrial antibody (AMA) status; 73 of 535 (13.6%) were non-Caucasian (21 were African American, and 42 were Hispanic). Non-Caucasians were more likely than Caucasians to be ineligible for participation in the clinical trial (46.5% versus 25.1%, P = 0.0001), primarily because of greater disease severity. African Americans and Hispanics were also more likely to have a lower activity level, more severe pruritus, and more advanced disease. However, the mean age, male-to-female ratio, and seroprevalence of AMA positivity were similar between the 2 groups. CONCLUSION: Liver disease severity at clinical presentation is higher among non-Caucasians than Caucasians with PBC, and this cannot be explained by demographic or serologic features alone. Possible mechanisms underlying this health discrepancy are not clear, but increased awareness of PBC as a cause of chronic cholestatic liver disease is critical in evaluating non-Caucasian patients in the United States.     

Long-term prediction of hepatocellular carcinoma using serum autotaxin levels after antiviral therapy for hepatitis C

Introduction and objectivesContinuous monitoring for hepatocellular carcinoma is necessary following treatment with direct-acting antivirals in patients with hepatitis C virus infection. We investigated whether the long-term follow-up of serum autotaxin levels could predict the development of hepatocellular carcinoma.Patients and MethodsThis prospective observational study enrolled adult patients with chronic hepatitis C virus infection who presented to the study center from January 2016 to March 2021. Among the patients who achieved a sustained viral response, the relationship between the development of hepatocellular carcinoma and serum autotaxin levels was assessed before treatment with direct-acting antivirals; at the end of therapy; at 12 and 24 weeks; and at 12, 24, 36, and 48 months after treatment.ResultsData were analyzed for 139 patients. Thirteen patients developed hepatocellular carcinoma 48 months after treatment. The cut-off serum autotaxin values that predicted hepatocellular carcinoma after 24 weeks were 1.22 (men) and 1.92 (women) mg/L. The area under the curve for serum autotaxin was 0.83 (95% confidence interval [CI]:0.71–0.95) in men and 0.90 (95% CI: 0.82–0.99) in women. The positive predictive value of serum autotaxin was 0.208 (95% CI: 0.139–0.248), and the negative predictive value was 0.971 (95% CI: 0.939–0.990). The cumulative incidence of hepatocellular carcinoma was significantly higher when serum autotaxin levels were above the cut-off value after 24 weeks (p < 0.0001).ConclusionsSerum autotaxin is a candidate biomarker for predicting hepatocellular carcinoma during the long-term follow-up of patients with a sustained viral response following treatment with direct-acting antivirals.     

Hepatic copper content is normal in early primary biliary cirrhosis and primary sclerosing cholangitis

In previous studies, the majority of patients with the cholestatic liver diseases, primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), had increased hepatic copper (Cu) levels even in early stages of disease. We prospectively measured hepatic copper content by atomic absorption spectrophotometry in 55 patients with PBC, 6 patients with PSC, and 29 patients with other chronic noncholestatic liver diseases. Hepatic Cu content was normal in 22/61 (36%) of patients with PBC or PSC; 18 of the 22 did not have cirrhosis (82%). Hepatic Cu content increased with increasing stage of disease (r=0.61,P<0.001) and was positively correlated with serum total bilirubin (r=0.6,P<0.0001) and alkaline phosphatase (r=0.5,P<0.001). All patients with stage I and II disease had hepatic Cu<150 µg/g dry weight, and all patients with hepatic Cu>150 µg/g dry weight had stage III and IV disease. Hepatic Cu content is normal in early PBC and PSC. Copper accumulation in the liver in these cholestatic liver diseases is secondary to cholestasis rather than a primary phenomenon.Supported by General Research Center grant MOIRR0054 from the National Institutes of Health.     

Relationship between pruritus and autotaxin in intrahepatic cholestasis of pregnancy

ObjectiveIntrahepatic cholestasis of pregnancy is a temporary, pregnancy-specific disease that resolves with delivery, characterized by itching (pruritus), as well as high transaminase and serum bile acid levels in the third trimester of pregnancy. Due to the effects of Autotaxin on the physiology of pregnancy, we aimed to investigate Autotaxin activity in patients with intrahepatic cholestasis of pregnancy.Patients and methodsSixty-nine patients diagnosed with intrahepatic cholestasis of pregnancy and 20 healthy pregnant women were enrolled in the study. Fasting serum bile acid, pruritus intensity, serum parameters, gestational week of the patients at the time of diagnosis were recorded, and birth week and birth weight were monitored. Autotaxin serum level was measured enzymatically.ResultsThe mean serum bile acid level (n = 69; 38.74 ± 35.92 μmol/L) in patients with intrahepatic cholestasis of pregnancy (n = 69) was detected to be higher than healthy pregnant women (n = 20; 5.05 ± 1.88 μmol/L) (p < 0.001). Weak correlation was detected between serum bile acid level and itch intensity (p = 0.014, r = 0.295), while no relation was detected between Autotaxin and itch intensity (p = 0.446, r = 0.09). Although mean Autotaxin (intrahepatic cholestasis of pregnancy: 678.10 ± 424.42 pg/mL, control: 535.16 ± 256.47 pg/mL) levels were high in patients with intrahepatic cholestasis of pregnancy, it was not statistically significant (p = 0.157).ConclusionIn our study, we observed that the serum Autotaxin level did not make a significant difference in patients with intrahepatic cholestasis of pregnancy compared to healthy pregnant women. These findings suggest that larger clinical studies are required to reveal the physio-pathological effects of Autotaxin on pregnancy.     

Potential involvement of adipocyte insulin resistance in obesity-associated up-regulation of adipocyte lysophospholipase D/autotaxin expression

Aims/hypothesis Autotaxin is a lysophospholipase D that is secreted by adipocytes and whose expression is substantially up-regulated in obese, diabetic db/db mice. The aim of the present study was to depict the physiopathological and cellular mechanisms involved in regulation of adipocyte autotaxin expression.Methods Autotaxin mRNAs were quantified in adipose tissue from db/db mice (obese and highly diabetic type 2), gold-thioglucose-treated (GTG) mice (highly obese and moderately diabetic type 2), high-fat diet-fed (HFD) mice (obese and moderately diabetic type 2), streptozotocin-treated mice (thin and diabetic type 1), and massively obese humans with glucose intolerance.Results When compared to non-obese controls, autotaxin expression in db/db mice was significantly increased, but not in GTG, HFD, or streptozotocin-treated mice. During db/db mice development, up-regulation of autotaxin occurred only 3 weeks after the emergence of hyperinsulinaemia, and simultaneously with the emergence of hyperglycaaemia. Adipocytes from db/db mice exhibited a stronger impairment of insulin-stimulated glucose uptake than non-obese and HFD-induced obese mice. Autotaxin expression was up-regulated by treatment with TNF (insulin resistance-promoting cytokine), and down-regulated by rosiglitazone treatment (insulin-sensitising compound) in 3T3F442A adipocytes. Finally, adipose tissue autotaxin expression was significantly up-regulated in patients exhibiting both insulin resistance and impaired glucose tolerance.Conclusions/interpretation The present work demonstrates the existence of a db/db-specific up-regulation of adipocyte autotaxin expression, which could be related to the severe type 2 diabetes phenotype and adipocyte insulin resistance, rather than excess adiposity in itself. It also showed that type 2 diabetes in humans is also associated with up-regulation of adipocyte autotaxin expression.     

Therapeutics for Pruritus in Cholestatic Liver Disease: Many Treatments but Few Cures

Purpose of Review

Pruritus in cholestatic liver disease is commonly encountered and difficult to eradicate. It has a major impact on quality of life and thus is important to address. This article reviews current and future treatment options for cholestatic pruritus.

Recent Findings

In the last 5 years, the pathogenesis of cholestatic itch has been further clarified via studies of serum autotaxin, which correlates with severity of symptoms and decrease in patients on therapy. New medications under development include apical sodium-dependent bile acid transporters (maralixibat, GSK2330672), fibrates (bezafibrate), and κ-opioid receptor agonists (nalfurafine hydrochloride).

Summary

While many treatments are available to treat this vexing condition, data to support consistent and dramatic improvement with any one medication is lacking. However, with so many options and several new medications under investigation in clinical trials, symptom relief is an achievable goal for many patients.

     

Natural history of pruritus in primary biliary cirrhosis.

The natural history of pruritus in primary biliary cirrhosis (PBC) remains poorly defined. The aim of this investigation was to evaluate outcomes of pruritus in clinical trials for ursodeoxycholic acid (UDCA). In a UDCA-placebo trial begun in 1988 (n = 180), a 55% prevalence rate for pruritus was observed. Serum alkaline phosphatase level and Mayo risk score were independent risk factors for pruritus (P < 0.0001). Among placebo-treated patients (n = 91), the annual risks for development or improvement/resolution of pruritus were 27% and 23%, respectively. For UDCA-treated patients (n = 89), a trend toward improvement in pruritus was observed after 1 year compared to placebo (30% vs. 23%, P = 0.08) but not at 2 or 3 years. In a 3-dose UDCA trial begun in 1995 (n = 155), the overall prevalence of pruritus was significantly lower at 37% when compared to UDCA-placebo participants (P < 0.001). Baseline serum alkaline phosphatase level and Mayo risk score were again independent risk factors for pruritus (P < 0.0001). Among 13 (3.9%) patients with refractory pruritus, symptom resolution (n = 5) or improvement (n = 8) was associated with the use of oral rifampin (300 or 600 mg daily). Two patients treated with rifampin developed biochemical evidence for hepatotoxicity necessitating drug withdrawal. Although less prevalent among recently diagnosed individuals, more than one third of PBC patients develop pruritus. No significant risk reduction in developing pruritus with UDCA therapy was observed compared to placebo-treated patients. The long-term administration of rifampin for refractory pruritus is associated with occasional hepatotoxicity.     

22例原发性胆汁性肝硬化的临床分析

目的 研究原发性胆汁性肝硬化（PBC）的临床特点、实验室检查、治疗转归，提高对PBC的认识。方法 分析22例PBC的临床表现、实验室检查及治疗转归。结果 22例PBC中女性20例，发病平均年龄51岁，主要症状包括皮肤瘙痒、乏力、纳差、腹痛，主要体征包括黄疸、肝大、脾大、腹水，实验室检查以ALP、高GGT、高胆红素血症、高球蛋白血症、存在多种自身抗体如抗线粒体抗体（AMA）、AMA－M2及抗核抗体（ANA）等，多数患者血ALT、AST升高，所有患者血清AST高于ALT。出现症状至临床确诊时间为2月－5年，平均8个月。治疗采用以熊去氧胆酸（UCDA）为主的综合方法，治疗3个月后ALP及TBil下降达50％以上者有12例，72．7％症状改善，死亡2例。结论 PBC以中年女性多，以肝脾肿大、黄疸、瘙痒、乏力为主要临床表现，肝功能异常以胆汁淤积为主，伴有高球蛋白血症及自身抗体；UCDA能够改善患者的症状和部分肝功能异常。     

Diagnosis and therapy of intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is characterized by the occurrence of pruritus mostly in the third trimenon. Diagnosis is based on the presence of pruritus and elevated levels of serum bile acids in the absence of pruritic skin diseases. There is strong evidence of a genetic predisposition for ICP. Numerous studies have investigated the association of known cholestasis genes such as ABCB4 (also designated MDR3), ABCB11 ( BSEP) and ATP8B1 ( FIC1) with ICP. The results of these studies implicate a heterogeneous etiology of this syndrome. ICP increases the risk of preterm delivery and fetal loss. Furthermore, intense pruritus may necessitate premature induction of labor with its known higher frequency of complications for mother and child. Therefore, ICP pregnancies should be managed as high-risk pregnancies. Pharmaceuticals to alleviate pruritus or improve cholestasis like antihistamines, phenobarbital, anion exchange resins, dexamethasone or S-adenosylmethionine are not widely accepted because of questionable efficacy or side effects. Recent randomized studies have shown beneficial effects of ursodeoxycholic acid (UDCA) on laboratory data and pruritus in patients with ICP. Improved knowledge about the diagnostic classification of different types and pathophysiological mechanisms of ICP may allow for a more targeted treatment of this disease in future.