Ezetimibe: A biomarker for efficacy of liver directed UGT1A1 gene therapy for inherited hyperbilirubinemia

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• 作者：Paula S. Montenegro-Miranda^a ; ¹ ; Nina Sneitz^b ; ^c ; ¹ ; D. Rudi de Waart^a ; Lysbeth ten Bloemendaal^a ; Suzanne Duijst^a ; Robert J. de Knegt^d ; Ulrich Beuers^a ; Moshe Finel^b ; Piter J. Bosma^a ; ^{p.j.bosma@amc.uva.nl}
• 关键词：UCB ; unconjugated bilirubin ; BMG ; bilirubin mono-glucuronide ; BDG ; bilirubin di-glucuronide ; AAV ; adeno鈥恆ssociated virus ; scAAV ; self complementary AAV ; CNI ; Crigler-Najjar syndrome type I ; CN II ; Crigler-Najjar syndrome type II ; UGT1A1 ; uridine 5'-di-p
• 刊名：Biochimica et Biophysica Acta (BBA)/Molecular Basis of Disease
• 出版年：2012
• 期刊代码：19_09254439
• 类别：bio
• 出版时间：August, 2012
• 卷：1822
• 期：8
• 页码：1223-1229
• 文件大小：563 K

摘要

As recently demonstrated in patients with factor IX deficiency, adeno鈥恆ssociated virus (AAV)-mediated liver-directed therapy is a viable option for inherited metabolic liver disorders. Our aim is to treat Crigler-Najjar syndrome type I (CN I), an inherited severe unconjugated hyperbilirubinemia, as a rare recessive inherited disorder. Because the number of patients eligible for this approach is small, the efficacy can only be demonstrated by a beneficial effect on the pathophysiology in individual patients. Serum bilirubin levels in potential candidates have been monitored since birth, providing an indication of their pathophysiology. Adjuvant phototherapy to prevent brain damage reduces serum unconjugated bilirubin (UCB) levels in CN I patients to the level seen in the milder form of the disease, CN type II. This therapy increases the excretion of UCB, thereby complicating the use of UCB and conjugated bilirubin levels in serum as biomarkers for the gene therapy we try to develop. Therefore, a suitable biomarker that is not affected by phototherapy is currently needed. To this end, we have investigated whether estradiol, ethinylestradiol or ezetimibe could be used as markers for uridine 5'-di-phospho-glucuronosyltransferase isoform 1A1 (UGT1A1) activity restored by AAV gene therapy in Gunn rats, a relevant animal model for CN I. Of these compounds, ezetimibe appeared most suitable because its glucuronidation rate in untreated control Gunn rats is low. Subsequently, ezetimibe glucuronidation was studied in both untreated and AAV-treated Gunn rats and the results suggest that it may serve as a useful serum marker for restored hepatic UGT1A1 activity.