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Obesity and PM2.5 Exposure Effects Cardiac Function During Exercise in Mice
Author(s) -
Grimmer Jacob,
Tanwar Vineeta,
Katapadi Aashish,
Youtz Dane,
Schwieterman Neill,
Baer Lisa,
Stanford Kristin,
Wold Loren
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.854.4
Subject(s) - medicine , diastole , cardiac function curve , endocrinology , cardiology , treadmill , obesity , leptin , sedentary lifestyle , heart failure , blood pressure
Objective Studies have demonstrated that particulate matter with diameter <2.5μm (PM 2.5 ) exposure is linked to cardiovascular disease (CVD). Risk factors, such as obesity, correlate with higher occurrences of CVD. We aimed to study PM 2.5 effects on cardiac function of obese mice and whether exercise could alter function. Methods Obese mice (Ob/Ob) (leptin deficient, FVB background) were exposed to either filtered air (FA) or PM 2.5 (within the annual average range of 15 μg/m 3 according to National Ambient Air Quality Standards (NAAQS)) for 6 h/day, 7 days/week for 9 months. The mice were divided into four groups: (1) FA sedentary, (2) FA treadmill exercise, (3) PM 2.5 sedentary, and (4) PM 2.5 treadmill exercise. After 8 weeks of exercise, echocardiography was used to examine global cardiac function. Following sacrifice, cardiomyocytes were isolated for studying cardiomyocyte function. Separate groups of sedentary mice were sacrificed for studying baseline myocardial mRNA expression. Results Echocardiography showed increased left ventricular end systolic (LVESd) and diastolic (LVEDd) diameters and decreased posterior wall thickness during systole (PWTs) and diastole (PWTd) in ob/obPM 2.5 sedentary mice compared to ob/ob FA sedentary mice. Morphological alterations were associated with lower systolic function as indicated by reduced percent fractional shortening (%FS) in ob/ob PM 2.5 sedentary mice compared to ob/obFA sedentary mice. These functional results are suggestive of contractile dysfunction leading to left ventricular volume overload. Cardiomyocytes isolated from sedentary ob/obPM 2.5 mice showed no change in peak shortening (%PS) but marked reduction in positive and negative contractile velocity (±dL/dT) and increased calcium transient amplitude (Δ340/380) suggesting cellular contractile dysfunction. Comparison of mice after 8 weeks of exercise training demonstrated significant decrease in %FS, increase in LVESd and no change in LVEDd in ob/obPM 2.5 exercised mice compared to ob/obFA exercised mice, suggesting systolic dysfunction. On comparing ob/obPM 2.5 exercise and ob/obFA exercise with their respective sedentary counterparts decrease in %FS, PWTs and PWTd and increase in LVESd was observed. qPCR data showed increased inflammatory markers ICAM‐1, VCAM and CRP in ob/obPM 2.5 sedentary mice compared to ob/obFA mice. These results indicated exercise did not improve cardiac function following exposure to PM 2.5 . Conclusions PM 2.5 exposure in combination with obesity induced cardiac dysfunction as seen through echocardiography. Exercise training, however, did not improve cardiac function in obese PM 2.5 mice. Support or Funding Information This work is supported by funding from National Institutes of Health (RO1ES019923) to LEW. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .