Residential Proximity to Major Roadways Is Associated With Increased Levels of AC133 ⁺ Circulating Angiogenic Cells

Abstract

Objective Previous studies have shown that residential proximity to a roadway is associated with increased cardiovascular disease (CVD) risk. Yet the nature of this association remains unclear, and its impact on individual CVD risk factors has not been assessed. The objective of this study was to determine whether residential proximity to roadways influences systemic inflammation and the levels of circulating angiogenic cells. Approach and Results In a cross-sectional study, CVD risk factors, blood levels of C-reactive protein (CRP), and 15 antigenically-defined circulating angiogenic cell populations were measured in participants (n=316) with moderate to high CVD risk. Attributes of roadways surrounding residential locations were assessed using Geographic Information Systems. Associations between road proximity and cardiovascular indices were analyzed using Generalized Linear Models. Close proximity (<50m) to a major roadway was associated with lower income and higher rates of smoking, but not CRP levels. After adjustment for potential confounders, levels of circulating angiogenic cell in peripheral blood were significantly elevated in people living in close proximity to a major roadway (CD31+/AC133+, AC133+, CD34+/AC133+, and CD34+/45dim/AC133+ cells); and positively associated with road segment distance (CD31+/AC133+, AC133+, and CD34+/AC133+ cells), traffic intensity (CD31+/AC133+ and AC133+ cells), and distance-weighted traffic intensity (CD31+/34+/45+/AC133+ cells). Conclusions Living close to a major roadway is associated with elevated levels of circulating cells positive for the “early” stem marker, AC133+. This may reflect an increased need for vascular repair. Levels of these cells in peripheral blood may be a sensitive index of cardiovascular injury due to residential proximity to roadways.

Vascular Regeneration by Stem/Progenitor Cells

“…The study of circulating endothelial progenitors, termed endothelial progenitor cells (EPCs), became an extremely attractive field of research after they were first isolated by Asahara et al 7 in 1997, using magnetic bead selection based on expression of specific cell surface antigens. Though a large number of articles have since been published using the term EPCs, [8][9][10] its initial use was a misnomer because the surface markers used for cell isolation and characterization, such as vascular endothelial growth factor receptor 2 (VEGFR2) and CD133, 11 are now known not to be specific for endothelial lineages. 12 In spite of this, the term EPC still appears in the literature though there is great controversy about its relevance.…”

Road Repairs

“…In this edition of the journal, DeJarnett et al 16 elaborate on another potentially important mechanism through which traffic-derived air pollution could promote cardiovascular disease. The authors studied 316 individuals with cardiovascular risk factors and examined whether angiogenic cells in blood are related to the proximity of their residence to major roadways.…”

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Editorialby guest on May 8, 2018 http://atvb.ahajournals.org/

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Miller et al Traffic Exposure and Angiogenic Cells 2267DeJarnett et al 16 raise an important limitation of the study, that the design does not assess exposure on an individual level. Potential exposure to traffic-related pollutants was based on the location of the volunteers' residential address and did not account for time spent in this residence or activity when not at this location.

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Do the pollution related to high-traffic roads in urbanised areas pose a significant threat to the local population?

“…Increased NO 2 level and presence of PM 2.5 particles in the atmosphere may also be related to the risk of increased cholesterol level (Sørensen et al, 2015). Many hours of staying in places of residence located near high-traffic roads is connected with increased level of the AC133+ stem cells responsible for processes of blood vessel reparation, the presence of which in peripheral blood may be an early indicator of damage to the cardiovascular system (caused to a high extent by particles with PM 2.5 diameter) (De Jarnett et al, 2015). Exposure to noise and air pollution may also lead to elevated peripheral blood pressure and increase the risk of cardiovascular diseases (Chang et al, 2015; Miller et al, 2015; Fecht et al, 2016).…”