title: Inhalation of inorganic particles as a risk factor for idiopathic pulmonary fibrosis--elemental microanalysis of pulmonary lymph nodes obtained at autopsy cases.
abstract: Exposure to inorganic particles may induce fibrosis in the lung. However, the association between exposure to inorganic particles and the pathogenesis of idiopathic pulmonary fibrosis (IPF)/usual interstitial pneumonia (UIP) is obscure. We examined inorganic particles in the pulmonary hilar lymph nodes affected by IPF/UIP to investigate whether inhaled elements are involved in the etiology, and whether there is an increasing risk of developing IPF/UIP. Twenty-three IPF/UIP cases and 23 controls without IPF/UIP were investigated. Pulmonary hilar lymph nodes constituted the study material. The elemental analysis was performed using scanning electron microscopy with an energy dispersive X-ray spectroscope, and we analyzed particles quantitatively and qualitatively. The results showed that the cases contained silicon and aluminum as compared with the control in lymph nodes, and these deposits were statistically significantly associated with an increased risk of IPF/UIP (adjusted odds were 2.99, 95% CI: 1.29-6.85 and 57.84, 95% CI: 1.45-2306.19, respectively). In addition, higher nickel levels in lymph nodes were associated with lung cancer. This study shows that inorganic particles, such as Si and Al, have higher concentrations in the hilar lymph nodes in IPF/UIP, and may play a role in one of the risk factors in the pathogenesis of IPF/UIP.
authors.affiliation: The Division of Respiratory Medicine, Department of Internal Medicine, The Jikei University School of Medicine, Japan. hidek5@jikei.ac.jp
authors.forename: Hideya
authors.initials: H
authors.lastname: Kitamura
authors.forename: Shizuko
authors.initials: S
authors.lastname: Ichinose
authors.forename: Takumi
authors.initials: T
authors.lastname: Hosoya
authors.forename: Tsunehiro
authors.initials: T
authors.lastname: Ando
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ikushima
authors.forename: Masaru
authors.initials: M
authors.lastname: Oritsu
authors.forename: Tamiko
authors.initials: T
authors.lastname: Takemura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000535:Aluminum / Q000009:adverse effects*; D001344:Autopsy; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000139:chemically induced*; D001239:Inhalation; D007287:Inorganic Chemicals / Q000009:adverse effects; D008198:Lymph Nodes / Q000737:chemistry*; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects*; D012307:Risk Factors; D012825:Silicon / Q000009:adverse effects*; D013052:Spectrometry, X-Ray Emission
chemical_list: D007287:Inorganic Chemicals; D052638:Particulate Matter; D000535:Aluminum; D012825:Silicon