title: Effects of ozone and particulate matter on cardiac mechanics: role of the atrial natriuretic peptide gene.
abstract: A positive association between air pollution exposure and increased human risk of chronic heart disease progression is well established. In the current study, we test two hypotheses: (1) the cardiac compensatory changes in response to air pollution are dependent on its composition and (2) specific cardiac adaptations are regulated by atrial natriuretic peptide (ANP). We address these hypotheses by initially examining the exposure effects of ozone (O(3)) and/or particulate matter (PM) on cardiac function in C57Bl/6J (B6) mice. Subsequently, the results are compared with cardiac functional changes to the same exposures in Nppa (the precursor gene for ANP) knockout (KO) mice. Separate groups of mice underwent 3 consecutive days of the same exposure sequence for 3h each consisting of the following: (1) 6h of filtered air (FAFA), (2) O(3) then FA (O(3)FA), (3) FA then carbon black (FACB), or (4) O(3) then CB. Cardiac function was assessed using a conductance catheter to generate cardiac pressure-volume loops 8-10h following each exposure sequence. As compared with FAFA, each sequence led to a substantial drop (as much as 33%) in stroke volume and cardiac output. However, these losses of cardiac function occurred by different compensatory mechanisms dependent on the pollutant composition. For example, O(3)FA exposure led to reductions in both end-systolic and end-diastolic left ventricular (LV) volumes, whereas FACB exposure led an increase in end-diastolic LV volume. These same cardiac compensatory changes were largely abolished in Nppa KO mice following O(3)FA or FACB exposure. These results suggest that cardiac functional changes in response to air pollution exposure are strongly dependent on the pollutant constituents, especially related to O(3) and/or PM. Furthermore, ANP regulation appears to be crucial to these cardiac compensatory mechanisms induced by air pollution.
authors.affiliation: Johns Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland 21205, USA. ctankers@jhsph.edu
authors.forename: Clarke G
authors.initials: CG
authors.lastname: Tankersley
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Georgakopoulos
authors.forename: Wan-Yee
authors.initials: WY
authors.lastname: Tang
authors.forename: Eric
authors.initials: E
authors.lastname: Abston
authors.forename: Alexis
authors.initials: A
authors.lastname: Bierman
authors.forename: Nicole
authors.initials: N
authors.lastname: Sborz
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D009320:Atrial Natriuretic Factor; D001835:Body Weight / Q000187:drug effects; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D015870:Gene Expression / Q000187:drug effects; D059647:Gene-Environment Interaction; D006334:Heart Function Tests; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D020098:Natriuretic Peptide, C-Type / Q000235:genetics*; D009929:Organ Size / Q000187:drug effects; D010126:Ozone / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity*; D011014:Pneumonia / Q000139:chemically induced / Q000235:genetics / Q000503:physiopathology; D011498:Protein Precursors / Q000235:genetics*; D016277:Ventricular Function, Left / Q000187:drug effects* / Q000235:genetics; D016278:Ventricular Function, Right / Q000187:drug effects* / Q000235:genetics
chemical_list: D000393:Air Pollutants; C431578:Nppa protein, mouse; D052638:Particulate Matter; D011498:Protein Precursors; D020098:Natriuretic Peptide, C-Type; D010126:Ozone; D009320:Atrial Natriuretic Factor