Liver transplantation for acute intermittent porphyria: Biochemical and pathologic studies of the explanted liver

Makiko Yasuda, Angelika L. Erwin, Lawrence U. Liu, Manisha Balwani, Brenden Chen, Senkottuvelan Kadirvel, Lin Gan, M. Isabel Fie, Ronald E. Gordon, Chunli Yu, Sonia Clavero, Antonios Arvelakis, Hetanshi Naik, L. David Martin, John D. Phillips, Karl E. Anderson, Vaithamanithi M. Sadagoparamanujam, Sander S. Florman, Robert J. Desnick

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Acute intermittent porphyria (AIP) is an autosomal-dominant hepatic disorder caused by the half-normal activity of hydrox-ymethylbilane (HMB) synthase. Symptomatic individuals experience life-threatening acute neurovisceral attacks that are precipitated by factors that induce the hepatic expression of 5-aminolevulinic acid synthase 1 (ALAS1), resulting in the marked accumulation of the putative neurotoxic porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). Here, we provide the first detailed description of the biochemical and pathologic alterations in the explanted liver of an AIP patient who underwent orthotopic liver transplantation (OLT) due to untreatable and debilitating chronic attacks. After OLT, the recipient's plasma and urinary ALA and PBG rapidly normalized, and her attacks immediately stopped. In the explanted liver, (a) ALAS1 mRNA and activity were elevated approximately ~3- and 5-fold, and ALA and PBG concentrations were increased ~3- and 1,760-fold, respectively; (b) uroporphyrin III concentration was elevated; (c) microsomal heme content was sufficient, and representative cytochrome P450 activities were essentially normal; (d) HMB synthase activity was approximately half-normal (~42%); (e) iron concentration was slightly elevated; and (f) heme oxygenase I mRNA was increased approximately three-fold. Notable pathologic findings included nodular regenerative hyperplasia, previously not reported in AIP livers, and minimal iron deposition, despite the large number of hemin infusions received before OLT. These findings suggest that the neurovisceral symptoms of AIP are not associated with generalized hepatic heme deficiency and support the neurotoxicity of ALA and/or PBG. Additionally, they indicate that substrate inhibition of hepatic HMB synthase activity by PBG is not a pathogenic mechanism in acute attacks.

Original languageEnglish (US)
Pages (from-to)487-495
Number of pages9
JournalMolecular Medicine
Volume21
DOIs
StatePublished - Jun 5 2015

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics
  • Genetics(clinical)

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