Chlorine (Cl2) gas mediated injury is complex involving a direct toxicity that occurs during the exposure and a robust post exposure toxicity that occurs over hrs-days to the airways, pulmonary and systemic vasculature. Preliminary data and our recently published studies show that injury post Cl2 exposure includes significant decreases in NO-bioavailability as indexed by diminution of eNOS-dependent vasodilation in the pulmonary and extrapulmonary vasculature and demonstration that post Cl2 exposure administration of nitrite (an NO- repleting strategy) by a single IM injection, protects against acute lung injury, airway hyper-reactivity and importantly, mortality. In this proposal we will i) establish a therapeutic framework for the development for the use of nitrite as a post exposure therapeutic that can be administered in mass casualty scenarios. How post- Cl2 gas injury occurs is unclear. We show novel data that Cl2 gas increases lung and circulating chlorinated lipids (Cl-lip), which are ?-chloro fatty acids derived from plasmalogens. Cl-lip may serve as novel biomarkers for Cl2 exposure, but we also provide evidence that these species can themselves cause acute lung injury and airway epithelial cell dysfunction. Importantly, Cl-lip dependent toxicity can also be prevented by post-exposure nitrite therapy. Taken together, we hypothesize that Cl-lip are novel biomarkers and mediators of post Cl2 gas toxicity and that post-exposure nitrite therapy will attenuate Cl2 gas and Cl-lip dependent toxicity and will test this via the following Specific Aims: 1. Determine the role of Cl-lip in mediating Cl2 gas induced toxicity, 2. Determine optimal nitrite therapeutic conditions for attenuating lethal and sub-lethal Cl2 gas toxicity, 3. Determine safety / toxicology profiles for IM nitrite administration under GLP conditions. A combination of in vivo Cl2 gas exposure with ex vivo studies is proposed. We feel this research is both timely and important and anticipate will yield novel insights into molecular mechanisms of Cl2 gas toxicity and identify and develop therapeutic (countermeasure) strategies.

Public Health Relevance

Chlorine toxicity comprises injury to the lungs and pulmonary and systemic vasculatures. How this occurs, and how this can be prevented using post- exposure therapies is not known. We will determine how post-exposure toxicity develops with a focus on a class of novel effectors (chlorinated fatty acids) and develop a therapeutic framework for using nitrite (an active ingredient in FDA approved therapies for cyanide poisoning) to prevent Cl2 gas toxicity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project--Cooperative Agreements (U01)
Project #
5U01ES023759-02
Application #
8737258
Study Section
Special Emphasis Panel (ZRG1-MDCN-J (50))
Program Officer
Nadadur, Srikanth
Project Start
2013-09-18
Project End
2018-06-30
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
2
Fiscal Year
2014
Total Cost
$763,659
Indirect Cost
$130,112
Name
University of Alabama Birmingham
Department
Pathology
Type
Schools of Medicine
DUNS #
063690705
City
Birmingham
State
AL
Country
United States
Zip Code
35294
Honavar, Jaideep; Bradley, Eddie; Bradley, Kelley et al. (2014) Chlorine gas exposure disrupts nitric oxide homeostasis in the pulmonary vasculature. Toxicology 321:96-102