A breakthrough on Amanita phalloides poisoning: an effective antidotal effect by polymyxin B

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Juliana Garcia (Author) Other; Vera Marisa Costa (Author) Other; Alexandra T P Carvalho (Author) Other; Ricardo Silvestre (Author) Other; Jose Alberto Duarte (Author) FADEUP; Daniel F A R Dourado (Author) Other; Marcelo D Arbo (Author) Other; Teresa Baltazar (Author) Other; Ricardo Jorge Dinis Oliveira (Author) FMUP; Paula Baptista (Author) Other; Maria de Lourdes Bastos (Author) FFUP; Felix Carvalho (Author) FFUP

Journal

Title: Archives of Toxicology

Vol. 89

Pages: 2305-2323

ISSN: 0340-5761

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 25 Citations

Scopus - 26 Citations

Scientific classification

FOS: Medical and Health sciences > Basic medicine

Other information

Authenticus ID: P-00G-NRX

DOI: 10.1007/s00204-015-1582-x

Abstract (EN): Amanita phalloides is responsible for more than 90 % of mushroom-related fatalities, and no effective antidote is available. alpha-Amanitin, the main toxin of A. phalloides, inhibits RNA polymerase II (RNAP II), causing hepatic and kidney failure. In silico studies included docking and molecular dynamics simulation coupled to molecular mechanics with generalized Born and surface area method energy decomposition on RNAP II. They were performed with a clinical drug that shares chemical similarities to alpha-amanitin, polymyxin B. The results show that polymyxin B potentially binds to RNAP II in the same interface of alpha-amanitin, preventing the toxin from binding to RNAP II. In vivo, the inhibition of the mRNA transcripts elicited by alpha-amanitin was efficiently reverted by polymyxin B in the kidneys. Moreover, polymyxin B significantly decreased the hepatic and renal alpha-amanitin-induced injury as seen by the histology and hepatic aminotransferases plasma data. In the survival assay, all animals exposed to alpha-amanitin died within 5 days, whereas 50 % survived up to 30 days when polymyxin B was administered 4, 8, and 12 h post-alpha-amanitin. Moreover, a single dose of polymyxin B administered concomitantly with alpha-amanitin was able to guarantee 100 % survival. Polymyxin B protects RNAP II from inactivation leading to an effective prevention of organ damage and increasing survival in alpha-amanitin-treated animals. The present use of clinically relevant concentrations of an already human-use-approved drug prompts the use of polymyxin B as an antidote for A. phalloides poisoning in humans.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 19