The authors declare that they have no competing interests.
HJ, JR, SG and KM designed the study. HJ, LP and KM recruited all participants. HJ obtained and processed all samples, analysed the data, and drafted the manuscript. All authors contributed to and approved the final manuscript.
Air pollution is associated with a high burden or morbidity and mortality, but exposure cannot be quantified rapidly or cheaply. The particulate burden of macrophages from induced sputum may provide a biomarker. We compare the feasibility of two methods for digital quantification of airway macrophage particulate load.
Induced sputum samples were processed and analysed using ImageJ and Image SXM software packages. We compare each package by resources and time required.
13 adequate samples were obtained from 21 patients. Median particulate load was 0.38 μm2 (ImageJ) and 4.0 % of the total cellular area of macrophages (Image SXM), with no correlation between results obtained using the two methods (correlation coefficient = −0.42, p = 0.256). Image SXM took longer than ImageJ (median 26 vs 54 mins per participant, p = 0.008) and was less accurate based on visual assessment of the output images. ImageJ’s method is subjective and requires well-trained staff.
Induced sputum has limited application as a screening tool due to the resources required. Limitations of both methods compared here were found: the heterogeneity of induced sputum appearances makes automated image analysis challenging. Further work should refine methodologies and assess inter- and intra-observer reliability, if these methods are to be developed for investigating the relationship of particulate and inflammatory response in the macrophage.
Lim SS, Vos T, Flaxman AD, Danaei G, Shibuya K, Adair-Rohani H, et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2013;380(9859):2224–60. CrossRef
Gordon SB, Bruce NG, Grigg J, Hibberd PL, Kurmi OP, Lam KB, et al. Respiratory risks from household air pollution in low and middle income countries. Lancet Res Med. 2014;2(10):823–60. CrossRef
Mehta S, Shin H, Burnett R, North T, Cohen AJ. Ambient particulate air pollution and acute lower respiratory infections: a systematic review and implications for estimating the global burden of disease. Air QualityAtmosphere Health. 2013;6(1):69–83. CrossRef
Yu CP, Xu GB. Predictive models for deposition of inhaled diesel exhaust particles in humans and laboratory species. Res Rep Health Eff Inst. 1987;10:3–22. PubMed
Bai Y, Brugha RE, Jacobs L, Grigg J, Nawrot TS, Nemery B. Carbon loading in airway macrophages as a biomarker for individual exposure to particulate matter air pollution - A critical review. Environ Int. 2014;74C:32–41.
Barrett SD. Image SXM. In ., v1.92 edn; 2011 http://www.ImageSXM.org.uk. Accessed 28/06/2013.
Fullerton DG. Indoor Air Pollution from biomass fuel smoke and its effect of respiratory health, in a population at risk of HIV related pneumonia. University of Liverpool: PhD Thesis; 2011.
Rylance J. The role of redox balance in pulmonary innate immunity. University of Liverpool: PhD thesis; 2012.
Miranda AI, Martins V, Cascao P, Amorim JH, Valente J, Borrego C, et al. Wildland smoke exposure values and exhaled breath indicators in firefighters. J Toxic Environ Health A. 2012;75(13–15):831–43. CrossRef
- Comparison of methods for the analysis of airway macrophage particulate load from induced sputum, a potential biomarker of air pollution exposure
Stephen B. Gordon
- BioMed Central
Neu im Fachgebiet Innere Medizin
Meistgelesene Bücher aus der Inneren Medizin
Mail Icon II