Bronchial and Bronchiolar Fibrosis in Rats Exposed to 2,3-Pentanedione Vapors: Implications for Bronchiolitis Obliterans in humans

Introduction:
This article presents a study on the potential toxicity of 2,3-pentanedione (PD), a common food flavoring, for the respiratory tract. The study was conducted to characterize the toxicity of inhaled PD and to provide concentration-response data in laboratory animals. These data are needed to help establish whether PD is a safe substitute for diacetyl and to help set exposure limits to protect workers.

Key Points:

* The study exposed male and female Wistar-han rats and B6C3F1 mice to nominal concentrations of 0, 50, 100, or 200 ppm PD for 6 hours/day, 5 days/week for up to 12 days.
* The study found that inhalation of PD caused airway fibrosis in rats, but not in mice. The fibrotic airway lesions included both intraluminal polyps and intramural, constrictive lesions, sharing features of bronchiolitis obliterans (BO) in humans.
* The study also found that PD exposure caused inflammation and damage to the epithelial lining of the respiratory tract in both rats and mice.
* PD exposure caused an increase in neutrophils in the bronchoalveolar lavage fluid (BaLF) of rats and mice, as well as an increase in specific cytokines and growth factors in the BaLF of rats.
* The study suggests that PD inhalation may cause BO in humans and questions the use of PD as a replacement for diacetyl.

Main Message:
The study provides important evidence on the potential toxicity of PD for the respiratory tract, particularly its ability to cause fibrotic airway lesions in rats. The study suggests that PD inhalation may cause BO in humans and questions the use of PD as a replacement for diacetyl. The study highlights the need for further research to establish exposure limits and protect workers from the potential health risks associated with PD exposure.

Morgan, Daniel L., Micheal P. Jokinen, herman C. Price, William M. Gwinn, Scott M. Palmer, and Gordon P. Flake. “Bronchial and Bronchiolar Fibrosis in Rats Exposed to 2,3-Pentanedione Vapors: Implications for Bronchiolitis Obliterans in humans.” Toxicologic Pathology 40, no. 3 (april 2012): 448–65. https://doi.org/10.1177/0192623311431946.