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2024 Annual Meeting Report: New Case Studies and Reports Make NAMs More Relevant for the Toxicity Assessment of Inhaled Substances

By Margaret Whittaker posted 05-16-2024 11:33 AM

  
Holger Behrsing of the Institute for In Vitro Sciences jump-started the 2024 SOT Continuing Education (CE) course “Use of New Approach Methodologies for the Assessment of Inhaled Substances” with an overview of respiratory toxicity 2D and 3D test systems, where tiered approaches such as 2D pulmonary cell cultures are first used to screen respiratory toxicants and then followed by more complex 3D systems such as reconstituted human airways. His presentation underscores the importance of working with an experienced laboratory to select relevant test systems.
 
Next, Shaun McCullough of RTI International identified many of the challenges associated with in vitro NAMs: (1) selecting the appropriate NAM to assess toxicity at the tissue/organism-level; (2) limitations in predicting effects across a diverse population; and (3) delivering test articles to target cells/test systems to approximate relevant exposures.
 
Moving onto the practical application of NAMs to address regulatory requirements, Monique Perron of the US EPA and Marie Hargrove of Syngenta provided their respective insights, including an overview of Syngenta’s application of NAMs to the fungicide chlorothalonil as part of the re-registration process. This project represents an eight-year effort by Syngenta to develop an inhalation point of departure (POD) using an in vitro 3D human respiratory model (MucilAirTM) in lieu of a 90-day in vivo inhalation study. The Organisation for Economic Co-operation and Development (OECD) published a detailed chlorothalonil case study that serves as a valuable roadmap for others to follow.
 
Dave Allen of Inotiv unveiled two exciting developments relevant to inhalation NAMs: (1) the NICEATM Integrated Chemical Environment (ICE) now hosts an LC50 dataset for more than 1,025 chemicals that can be downloaded through the ICE Data Sets web page and (2) the newly released ICCVAM report titled Validation, Qualification, and Regulatory Acceptance of New Approach Methodologies that serves to strengthen confidence in the application of NAMs to replace, reduce, or refine (3Rs) the use of animals in testing.
 
As I reflected upon the teachings of the CE course, I listened to Moody Blue’s somber song “Late Lament,” which reminds us all to take a deep breath (very relevant here) and commit to the application of NAMs that are reliable, fit-for-purpose, and biologically relevant: “Breathe deep … the gathering gloom … watch lights fade from every room … but we decide what is right … and what is an illusion.” Thanks to publications such as the OECD chlorothalonil case study and the new ICCVAM NAM report, NAMs associated with inhaled substances are no longer apparition-like and are an effective means to advance the 3Rs originally championed by William Russell and Rex Burch.
 
This blog reports on the Continuing Education course titled “Use of New Approach Methodologies for the Assessment of Inhaled Substances” that was held during the 2024 SOT Annual Meeting and ToxExpo. All 2024 Continuing Education courses were recorded and are available for virtual viewing through the SOT CEd-Tox online library. SOT Postdocs and Students and individuals from select countries receive free access to all CE courses.
 
This blog was prepared by an SOT Reporter and represents the views of the author. SOT Reporters are SOT members who volunteer to write about sessions and events in which they participate during the SOT Annual Meeting and ToxExpo. SOT does not propose or endorse any position by posting this article. If you are interested in participating in the SOT Reporter program in the future, please email SOT Headquarters.


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