Exacerbation of acute viral myocarditis by tobacco smoke is associated with increased viral load and cardiac apoptosis.
Exposure to tobacco smoke is known to have deleterious cardiovascular effects. In this study, we tested whether exposure to tobacco smoke exacerbates the severity of viral myocarditis in mice. Viral myocarditis was generated in 4-week-old male BALB/c mice by injection of Encephalomyocarditis virus (EMCV). Four groups were studied: (1) control (C, no smoke and no virus); (2) smoke only (S, exposure to cigarette smoke for 90 min/day for 15 days); (3) virus only (V); and (4) exposure to smoke for 5 days before plus 10 days following virus injection (S+V). We found that viral inoculation preceded by smoke exposure increased mortality more than twofold compared with virus inoculation alone. In addition, the mRNA level of atrial natriuretic factor was significantly higher in S+V than among any of the other 3 groups. Virus injection significantly decreased cardiac function compared with controls, with further deterioration observed in the S+V group. We also observed a significantly increased rate of apoptosis, with an increased activation of apoptosis-inducing factor in hearts exposed to S+V compared with those exposed to V alone. Our results suggest that preexposure to smoke significantly exacerbates the severity of viral myocarditis, likely through increased viral load and increased cardiomyocyte cell death.
Bae
Soochan
S
Cardiovascular Division, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
Ke
Qingen
Q
Koh
Young Youp
YY
Lee
Wooseung
W
Choi
Jun H
JH
Kang
Peter M
PM
Morgan
James P
JP
D000818:Animals; D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000096:biosynthesis; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis; D015153:Blotting, Western; D018188:Cardiovirus Infections / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000821:virology*; D004686:Encephalomyocarditis virus; D006321:Heart / Q000821:virology*; D006439:Hemodynamics / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009205:Myocarditis / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000821:virology*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D019562:Viral Load
D051033:Apoptosis Inducing Factor; D014028:Tobacco Smoke Pollution; D009320:Atrial Natriuretic Factor