International Immunopharmacology 20 (2014) 358
Contents lists available at ScienceDirect
International Immunopharmacology journal homepage: www.elsevier.com/locate/intimp
Letter to the Editor Methylene blue protects against paraquat-induced acute lung injury in rats Paraquat (PQ) is one of the most toxic pesticides worldwide, responsible for thousands of deaths annually. With a mortality rate between 50 and 90% [1], researchers and clinicians have tried numerous therapies, but with no proven antidote still. Tian et al.'s investigation of methylene blue's effect on PQ-induced acute lung injury shows potential as another treatment option to this life-threatening exposure [2]. The authors were able to aptly demonstrate pulmonary histological improvement and decreased lung injury presumably through methylene blue's antioxidant effects. However, rats that received the singledose methylene blue (MB) did not have a survival benefit over the placebo arm. The relatively short half-life of MB might explain this lack of effect in the experiment after a single dose. Either repeating the dose or starting a continuous infusion of MB after the initial bolus dose might produce a survival benefit. As mentioned, earlier work suggests that staying below 7 mg/kg/day of MB might avoid the prooxidant effects. Methylene blue has been used as a continuous infusion in humans in cases of distributive shock including those from sepsis, cardiovascular toxins, and anaphylaxis [3]. Furthermore, the neurotoxicity from methylene blue seems to be specifically occurring in the setting of parathyroidectomy [4], alleviating some concerns for repeating the dose or starting a continuous infusion. Tian et al.'s results are promising. We encourage Tian's research team and other researchers to further study MB in repeated doses or as a continuous infusion as a potential treatment in PQ-induced acute lung injury. This would help delineate the true benefit of MB, or lack thereof.
http://dx.doi.org/10.1016/j.intimp.2014.03.012 1567-5769/© 2014 Elsevier B.V. All rights reserved.
References [1] Roberts DM. Herbicides. In: Nelson LS, editor. Goldfrank's toxicologic emergencies. 9th edition. New York City: The McGraw-Hill Companies; 2011. [2] Tian Zhi-guang, Yong Ji, Wen-jing Yan, Chuang-ying Xu, Qing-yan Kong, Feng Han, et al. Methylene blue protects against paraquat-induced acute lung injury in rats. Int Immunopharmacol Oct 2013;17(2):309–13. [3] Jang DH, Nelson LS, Hossman RS. Methylene blue for distributive shock: a potential new use for an old antidote. J Med Toxicol Sep 2013;9(3). [4] Shopes E, Gerard W, Baughman J. Methylene blue encephalopathy: a case report and review of published cases. AANA J 2013;81(3):215–21.
Vincent Nguyen New York University School of Medicine, Department of Emergency Medicine, United States Corresponding author. E-mail address: [email protected] Danish S. Malik St. Luke's-Roosevelt Hospital Center, Department of Emergency Medicine, United States E-mail address: [email protected] Mary Ann Howland New York University School of Medicine, United States St. John's University College of Pharmacy, United States St. John's University College of Pharmacy, United States E-mail address: [email protected] 1 December 2013
Contents lists available at ScienceDirect
International Immunopharmacology journal homepage: www.elsevier.com/locate/intimp
Letter to the Editor Methylene blue protects against paraquat-induced acute lung injury in rats Paraquat (PQ) is one of the most toxic pesticides worldwide, responsible for thousands of deaths annually. With a mortality rate between 50 and 90% [1], researchers and clinicians have tried numerous therapies, but with no proven antidote still. Tian et al.'s investigation of methylene blue's effect on PQ-induced acute lung injury shows potential as another treatment option to this life-threatening exposure [2]. The authors were able to aptly demonstrate pulmonary histological improvement and decreased lung injury presumably through methylene blue's antioxidant effects. However, rats that received the singledose methylene blue (MB) did not have a survival benefit over the placebo arm. The relatively short half-life of MB might explain this lack of effect in the experiment after a single dose. Either repeating the dose or starting a continuous infusion of MB after the initial bolus dose might produce a survival benefit. As mentioned, earlier work suggests that staying below 7 mg/kg/day of MB might avoid the prooxidant effects. Methylene blue has been used as a continuous infusion in humans in cases of distributive shock including those from sepsis, cardiovascular toxins, and anaphylaxis [3]. Furthermore, the neurotoxicity from methylene blue seems to be specifically occurring in the setting of parathyroidectomy [4], alleviating some concerns for repeating the dose or starting a continuous infusion. Tian et al.'s results are promising. We encourage Tian's research team and other researchers to further study MB in repeated doses or as a continuous infusion as a potential treatment in PQ-induced acute lung injury. This would help delineate the true benefit of MB, or lack thereof.
http://dx.doi.org/10.1016/j.intimp.2014.03.012 1567-5769/© 2014 Elsevier B.V. All rights reserved.
References [1] Roberts DM. Herbicides. In: Nelson LS, editor. Goldfrank's toxicologic emergencies. 9th edition. New York City: The McGraw-Hill Companies; 2011. [2] Tian Zhi-guang, Yong Ji, Wen-jing Yan, Chuang-ying Xu, Qing-yan Kong, Feng Han, et al. Methylene blue protects against paraquat-induced acute lung injury in rats. Int Immunopharmacol Oct 2013;17(2):309–13. [3] Jang DH, Nelson LS, Hossman RS. Methylene blue for distributive shock: a potential new use for an old antidote. J Med Toxicol Sep 2013;9(3). [4] Shopes E, Gerard W, Baughman J. Methylene blue encephalopathy: a case report and review of published cases. AANA J 2013;81(3):215–21.
Vincent Nguyen New York University School of Medicine, Department of Emergency Medicine, United States Corresponding author. E-mail address: [email protected] Danish S. Malik St. Luke's-Roosevelt Hospital Center, Department of Emergency Medicine, United States E-mail address: [email protected] Mary Ann Howland New York University School of Medicine, United States St. John's University College of Pharmacy, United States St. John's University College of Pharmacy, United States E-mail address: [email protected] 1 December 2013
