Chemical compositions and effects on chemiluminescence of AMs in vitro of chalk dusts

Chalk-induced Lung Fibrosis — Case Report

Introduction: Our article underlines the importance of a good professional anamnesis, knowing all the chemical components with which the patient had been exposed to during her active life as a teacher.

Case presentation: A 64-year-old female patient, teacher for 27 years, who had been retired for six years, presented cough with white phlegm and shortness of breath occurring during physical exertion, diffuse thoracic pain, and fatigue. Several lung functional tests were performed, which established the diagnosis of irreversible minor mixed ventilatory dysfunction. In order to establish the etiology of the patient’s symptoms, multiple clinical, laboratory, imaging, and functional investigations were performed including a chest radiograph, pulmonary functional testing, bronchial reversibility testing, a thoracic CT scan, fibrobronchoscopy, alveolar-capillary diffusion capacity measurement, otorhinolaryngology examination, thyroid ultrasound, as well as a cardiological consult. Finally, a positive diagnosis was established: bronchial hyperreactivity syndrome, chalk dust-induced diffuse pulmonary fibrosis.

Conclusion: An essential part of clinical practice is a proper anamnesis, including detailed information on the professional history and exposure, as well as the composition of the dust/particles with which the patient had been in contact with.

Effects of coarse chalk dust particles (2.5-10 μm) on respiratory burst and oxidative stress in alveolar macrophages

The main aim of the present study was to examine in vitro responses of rat alveolar macrophages (AMs) exposed to coarse chalk dust particles (particulate matter in the size range 2.5-10 μm, PM(coarse)) by respiratory burst and oxidative stress. Chalk PM(coarse)-induced respiratory burst in AMs was measured by using a luminol-dependent chemiluminescence (CL) method. Also, the cell viability; lactate dehydrogenase (LDH) release; levels of cellular superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), malondialdehyde (MDA), and acid phosphatase (ACP); plasma membrane ATPase; and extracellular nitric oxide (NO) level were determined 4 h following the treatment with the different dosages of chalk PM(coarse). The results showed that chalk PM(coarse) initiated the respiratory burst of AMs as indicated by strong CL, which was inhibited by diphenyleneiodonium chloride and L-N-nitro-L-arginine methyl ester hydrochloride. It suggested that chalk PM(coarse) induced the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in AMs. This hypothesis was confirmed by the fact that chalk PM(coarse) resulted in a significant decrease of intracellular SOD, GSH, ACP, and ATPase levels and a notable increase of intracellular CAT, MDA content, and extracellular NO level, consequently leading to a decrease of the cell viability and a increase of LDH release. It was concluded that AMs exposed to chalk PM(coarse) can suffer from cytotoxicity which may be mediated by generation of excessive ROS/RNS. Graphical Abstract The possible mechanism of coarse chalk particles-induced adverse effects in AMs.