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MYO5B and bile salt export pump contribute to cholestatic liver disorder in microvillous inclusion disease
Author(s) -
Girard Muriel,
Lacaille Florence,
Verkarre Virginie,
Mategot Raphael,
Feldmann Gerard,
Grodet Alain,
Sauvat Frédérique,
Irtan Sabine,
DavitSpraul Anne,
Jacquemin Emmanuel,
Ruemmele Frank,
Rainteau Dominique,
Goulet Olivier,
Colomb Virginie,
Chardot Christophe,
HenrionCaude Alexandra,
Debray Dominique
Publication year - 2014
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.26974
Subject(s) - progressive familial intrahepatic cholestasis , cholestasis , medicine , gastroenterology , liver disease , enterohepatic circulation , bile acid , bile salt export pump , liver transplantation , pathology , endocrinology , biology , transplantation , biochemistry , transporter , gene
Microvillous inclusion disease (MVID) is a congenital disorder of the enterocyte related to mutations in the MYO5B gene, leading to intractable diarrhea often necessitating intestinal transplantation (ITx). Among our cohort of 28 MVID patients, 8 developed a cholestatic liver disease akin to progressive familial intrahepatic cholestasis (PFIC). Our aim was to investigate the mechanisms by which MYO5B mutations affect hepatic biliary function and lead to cholestasis in MVID patients. Clinical and biological features and outcome were reviewed. Pretransplant liver biopsies were analyzed by immunostaining and electron microscopy. Cholestasis occurred before (n = 5) or after (n = 3) ITx and was characterized by intermittent jaundice, intractable pruritus, increased serum bile acid (BA) levels, and normal gamma‐glutamyl transpeptidase activity. Liver histology showed canalicular cholestasis, mild‐to‐moderate fibrosis, and ultrastructural abnormalities of bile canaliculi. Portal fibrosis progressed in 5 patients. No mutation in ABCB11/BSEP or ATP8B1/FIC1 genes were identified. Immunohistochemical studies demonstrated abnormal cytoplasmic distribution of MYO5B, RAB11A, and BSEP in hepatocytes. Interruption of enterohepatic BA cycling after partial external biliary diversion or graft removal proved the most effective to ensure long‐term remission. Conclusion : MVID patients are at risk of developing a PFIC‐like liver disease that may hamper outcome after ITx. Our results suggest that cholestasis in MVID patients results from (1) impairment of the MYO5B/RAB11A apical recycling endosome pathway in hepatocytes, (2) altered targeting of BSEP to the canalicular membrane, and (3) increased ileal BA absorption. Because cholestasis worsens after ITx, indication of a combined liver ITx should be discussed in MVID patients with severe cholestasis. Future studies will need to address more specifically the effect of MYO5B dysfunction in BA homeostasis. (H epatology 2014;60:301–310)