The effect of air pollution on the transcriptomics of the immune response to respiratory infection.

Combustion related particulate matter air pollution (PM) is associated with an increased risk of respiratory infections in adults. The exact mechanism underlying this association has not been determined. We hypothesized that increased concentrations of combustion related PM would result in dysregulation of the innate immune system. This epidemiological study includes 111 adult patients hospitalized with respiratory infections who underwent transcriptional analysis of their peripheral blood. We examined the association between gene expression at the time of hospitalization and ambient measurements of particulate air pollutants in the 28 days prior to hospitalization. For each pollutant and time lag, gene-specific linear models adjusting for infection type were fit using LIMMA (Linear Models For Microarray Data), and pathway/gene set analyses were performed using the CAMERA (Correlation Adjusted Mean Rank) program. Comparing patients with viral and/or bacterial infection, the expression patterns associated with air pollution exposure differed. Adjusting for the type of infection, increased concentrations of Delta-C (a marker of biomass smoke) and other PM were associated with upregulation of iron homeostasis and protein folding. Increased concentrations of black carbon (BC) were associated with upregulation of viral related gene pathways and downregulation of pathways related to antigen presentation. The pollutant/pathway associations differed by lag time and by type of infection. This study suggests that the effect of air pollution on the pathogenesis of respiratory infection may be pollutant, timing, and infection specific.

Angiographic evidence of peripheral ischemia in diabetic retinopathy and the risk of impending neovascularisation.

The appearance of biomicroscopic evidence of neovascularisation is the main indication for scatter laser treatment in patients with known diabetic eye disease. We describe a patient with an unusually aggressive variant of proliferative disease and a distinct angiographic signature. In an interventional case report with angiographic findings, we found that angiographic evidence of extensive capillary dropout in patients with known diabetic retinopathy should translate into a low threshold for panretinal photocoagulation treatment based on a high risk for progression to sight-threatening proliferative disease. Angiography may be a useful adjunct in stratifying patients with diabetic eye disease according to risk. Those with extensive ischemia, even without neovascularisation, should be considered for early panretinal photocoagulation.