Translocation of particles deposited in the respiratory system: a systematic review and statistical analysis

Abstract

Many epidemiological studies have demonstrated that ambient particulate matter poses consistent risks for respiratory and cardiovascular disorders. The translocation of inhaled particles is one hypothesis that could explain such systemic effects. The objectives of this study were to conduct a systematic review of previous reports on particle translocation from the respiratory system and to discuss factors important for translocation. A PubMed search was conducted in August 2011 for the period from 1967 with four main keyword domains (particle, translocation, detection site, and exposure route). The systematic review identified 61 original articles written in English that met the specified criteria (i.e., information on experiment and particle detection). Categorical regression analysis was performed with the site of particle detection as the objective variable, and particle size, particle material, animal species, and exposure route as the explanatory variables. All explanatory variables showed statistically significant effects. The effects for particle size and particle material were large, while the effects for animal species and exposure route were relatively small. There was a broad relationship between particle size and detection site: ≤50 nm for brain and remote organs; ≤1 μm for blood; and ≤10 μm for lung tissues. However, these results should be considered within the context of several limitations, such as deficiency of information.

Direct contact with particulate matter increases oxidative stress in different brain structures

“…Zanchi et al exposed animals cronically to urban air pollution, which contains not only PM, but also other polutants, like ozone. The effects of these polutants was only accessed in the cortex, but the origin of the oxidative stress is supposedly systemic, as described previously (Nakane, 2012;Rhoden et al, 2008). Conversely, our study has an isolated oxidative stress source (PM) and estimates the local protection for each brain area.…”

Air pollution and cytokine responsiveness in asthmatic and non-asthmatic children

“…There is strong evidence that systemic effects can be induced by inhaled PM, especially by ultrafine particles (UFPs) and nanoparticles (NPs) (Nemmar et al, 2013). One suggested mechanism is particle translocation from the lungs into the blood circulation (Nakane, 2012) where translocated particles might cause direct systemic effects like the release of pro-inflammatory mediators. The whole blood assay (WBA) is a suitable method to detect an altered stimulus-dependent production of systemic inflammatory markers (inflammatory responsiveness) caused by exposure to various environmental factors (Herberth et al, 2008;Schins et al, 1996).…”

Systemic and vascular effects of circulating diesel exhaust particulate matter

“…Our data are different from studies conducted by Nemmar et al (2007), who observed lung inflammation and increased cellular influx in the lung following injection of particles, an effect that could be dose and particle composition dependent. Other study reported that liver and kidneys also served as major organs to clear-off these ambient particles (Nakane, 2012).…”