Safety and efficacy of rifampicin in children with cholestatic pruritus

The Covert Surge: Murine Bile Acid Levels Are Associated With Pruritus in Pediatric Autoimmune Sclerosing Cholangitis

OBJECTIVES

The exact etiology of pruritus in chronic cholestasis is unknown. Pruritus intensity does not correlate with common biochemical indices and there is a lack of biomarkers guiding diagnosis and treatment. We explored profiles of bile acids (BA) and muricholic acids (MCA) as well as autotaxin (ATX) antigen levels as potential circulating biomarkers of pruritus in pediatric patients.

METHODS

In 27 pediatric cholestatic patients [autoimmune sclerosing cholangitis (ASC) n = 20 (with pruritus n = 6, without pruritus n = 14); progressive familial intrahepatic cholestasis (PFIC) n = 7 (with pruritus n = 5, without pruritus n = 2)] and 23 age-matched controls pruritus was assessed by a visual analog scale of pruritus (PVAS). We obtained profiles of serum human BA including MCA using a mass-spectrometry assay and ATX antigen levels with a commercial ELISA.

RESULTS

PFIC and ASC patients exhibited significantly higher BA-, and MCA levels, than healthy controls, but only PFIC patients showed elevated ATX antigen levels higher [median: 1,650 ng/ml, interquartile rang (IQR): 776.9-3,742] compared to controls (median: 315.9 ng/ml, IQR: 251.1-417.2; PFIC p = 0.0003). ASC patients with pruritus showed only a minor increase in total BA (tBA) levels (median: 76.5 μmol/L, IQR: 54.7-205), but strikingly higher T-conjugated BA (median: 16.4 μmol/L, IQR: 8.9-41.4) and total MCA (tMCA) (median: 1.15 μmol/L, IQR: 0.77-2.44) levels compared to ASC patients without pruritus (tBA median: 24.3 μmol/L, IQR: 16.2-80.8; p < 0.0408; T-conjugated BA median: 1.3 μmol/L, IQR: 0.8-4.9; p = 0.0023; tMCA median: 0.30 μmol/L, IQR: 0.13-0.64, p = 0.0033). BA/MCA profiles distinctly differed depending on presence/absence of pruritus. Different from PFIC patients, ATX antigen levels were not significantly elevated in ASC patients with (median: 665.8 ng/ml, IQR: 357.8-1,203) and without pruritus (median: 391.0 ng/ml, IQR: 283.2-485.6). In ASC patients, tBA, tMCA, and ATX antigen levels did not correlate with pruritus severity.

CONCLUSION

Despite the same underlying disease, pediatric ASC patients with pruritus exhibit significantly altered BA profiles and MCA levels compared to ASC patients without pruritus. ATX antigen levels seem to have little diagnostic or prognostic meaning in ASC patients. An increased ATX activity alone seems not to be causal for pruritus genesis in ASC patients.

CLINICAL TRIAL REGISTRATION

[www.drks.de], identifier [DRKS00026913].

Systemic causes of non-dermatologic chronic pruritus in the pediatric population and their management: An unexplored area

Chronic pruritus associated with systemic diseases in the pediatric population has been infrequently addressed in the literature. This review focuses on chronic pruritus presenting without cutaneous manifestations. Common systemic etiologies include diseases with hepatic, renal, and hematologic origins. This encompasses several congenital liver disorders, end-stage renal disease (ESRD), and lymphoproliferative disorders such as Hodgkin's lymphoma. In this paper, an expert panel describes the clinical characteristics, pathophysiology, and therapeutic treatment ladders for chronic pruritus associated with the aforementioned systemic etiologies. Novel therapies are also reviewed. Our aim is to shed light on this unexplored area of pediatric dermatology and instigate further research.

Chronic Kidney Disease-Associated Itch (CKD-aI) in Children-A Narrative Review

Chronic kidney disease (CKD) is a condition of widespread epidemiology and serious consequences affecting all organs of the organism and associated with significant mortality. The knowledge on CKD is rapidly evolving, especially concerning adults. Recently, more data is also appearing regarding CKD in children. Chronic itch (CI) is a common symptom appearing due to various underlying dermatological and systemic conditions. CI may also appear in association with CKD and is termed chronic kidney disease-associated itch (CKD-aI). CKD-aI is relatively well-described in the literature concerning adults, yet it also affects children. Unfortunately, the data on paediatric CKD-aI is particularly scarce. This narrative review aims to describe various aspects of CKD-aI with an emphasis on children, based on the available data in this population and the data extrapolated from adults. Its pathogenesis is described in details, focusing on the growing role of uraemic toxins (UTs), as well as immune dysfunction, altered opioid transmission, infectious agents, xerosis, neuropathy and dialysis-associated aspects. Moreover, epidemiological and clinical aspects are reviewed based on the few data on CKD-aI in children, whereas treatment recommendations are proposed as well, based on the literature on CKD-aI in adults and own experience in managing CI in children.

Rifampicin, not vitamin E, suppresses parenteral nutrition-associated liver disease development through the pregnane X receptor pathway in piglets

Infants receiving long-term parenteral nutrition (PN) develop PN-associated liver disease (PNALD). We previously (Ng K et al. JPEN J Parenter Enteral Nutr 40: 656-671, 2016. doi:10.1177/0148607114567900.) showed that PN containing soy-based lipid supplemented with vitamin E (α-tocopherol) prevents the development of PNALD. We hypothesize that this occurs via vitamin E activation of pregnane X receptor (PXR)-mediated pathways involved in bile acid metabolism. Neonatal piglets received PN for 14 days containing Intralipid (IL; soy-based lipid emulsion), IL supplemented with 12.6 mg·kg^-1·day^-1 vitamin E (VITE), or IL with 10 mg·kg^-1·day^-1 Rifadin IV (RIF), a PXR agonist. Pigs treated with IL and VITE, but not RIF, developed cholestasis and hyperbilirubinemia, markers of liver disease. The hepatic PXR target genes CYP3A29 and UGT1A6 increased during RIF treatment. RIF also modestly increased metabolism of chenodeoxycholic acid to the more hydrophilic bile acid hyocholic acid. Serum fibroblast growth factor (FGF)-19, a key regulator in suppressing hepatic bile acid synthesis, significantly increased in the RIF group. We conclude rifampicin modified markers of PNALD development by increased metabolism of bile acids and potentially suppressed bile acid synthesis. Vitamin E was ineffective at high lipid doses in preventing PNALD.NEW & NOTEWORTHY Intravenous vitamin E and rifampicin were administered to neonatal piglets receiving parenteral nutrition to determine their efficacy in reducing the progression of parenteral nutrition-associated liver disease (PNALD). Rifampicin increased serum FGF-19 concentrations and synthesis of the bile acid hyocholic acid which led to a reduction of PNALD parameters at 2 wk of administration. This result has potential clinical implications for the use of rifampicin as a safe and inexpensive treatment for short-term development of PNALD.

An update on the physiopathology and therapeutic management of cholestatic pruritus in children

Pruritus is a disabling symptom accompanying chronic cholestasis. In extreme cases, the refractory nature of pruritus can result in a need for invasive therapies including liver transplantation. The pathogenesis of pruritus in cholestatic disease is poorly understood. It may involve a specific neural pathway (similar to that associated with pain) regulated by several pruritogenic substances such as bile acids, opioids, serotonin, and the more recently identified lysophosphatidic acid. While the therapeutic management of cholestatic pruritus is well established in adults, there is no consensus in children, in light of the difficulty of conducting controlled clinical studies. The currently recommended strategy to manage cholestatic pruritus in children is based on several lines of specific therapies that should be associated with skin hydration and with non-specific treatment of cholestasis including ursodeoxycholic acid. Pruritus should be assessed as objectively as possible between each line of therapy. Rifampicin, a potent CYP3A4 inducer, is the first-line treatment of cholestatic pruritus. Second-line therapies require evaluation of the child in an expert center and are discussed on a case-by-case basis depending on the underlying disease and the experience of the center. These include inhibitors of serotonin reuptake (sertraline), opioid antagonists (naloxone), or ASBT inhibitors. Invasive therapies such as biliary diversion or liver transplantation can also be proposed in the most severe cases. The aim of the current update is to review the physiopathologic mechanisms implicated in cholestatic pruritus and to propose potential therapeutic strategies in children.

Child with Jaundice and Pruritus: How to Evaluate?

Jaundice with pruritus is a manifestation of cholestasis. The defective biliary drainage causes accumulation of substances that are usually excreted in bile, which in turn causes pruritus. The exact nature of the pruritogen is under evaluation. However, lysophosphatidic acid is the current favourite. The causes of cholestasis can be broadly classified as intra or extrahepatic, with intrahepatic disorders being more often associated with pruritus. Cholestatic phase of acute viral hepatitis, progressive familial intrahepatic cholestasis, syndromic and non-syndromic paucity of intralobular bile ductules, drug induced cholestasis and sclerosing cholangitis (SC) are the common causes in children. An algorithmic approach facilitates early etiological diagnosis by careful clinical evaluation combined with investigations including gamma glutamyl transpeptidase, radiological imaging (ultrasonography, magnetic resonance cholangiopancreatography), liver biopsy and genetic analysis. Management is largely supportive and includes nutritional rehabilitation with supplement of fat soluble vitamins and calcium, stepwise therapy of pruritus with drugs (ursodeoxycholic acid, rifampicin, bile acid sequestrants and/or opioid antagonists) and biliary diversion surgery. Complications of advanced liver disease and portal hypertension need to be addressed. Liver transplantation is required in children with refractory pruritus affecting the quality of life or those with end stage liver disease. Relief of biliary obstruction by endoscopy or surgery and treatment of diseases associated with SC like histiocytosis may be rewarding. Long-term follow-up for development of complications of liver disease and hepatocellular/ cholangiocarcinoma is essential. Thus, an early diagnosis and stepwise treatment with an understanding of the pathogenesis of pruritus in cholestatic disorders may decrease morbidity and mortality.