Cigarette smoke exacerbates ventricular remodeling and dysfunction in the volume overloaded heart

Area of Science:

• Cardiovascular Science
• Toxicology
• Cardiac Remodeling

Background:

• Cigarette smoking (CS) is a major risk factor for heart disease and sudden cardiac death.
• Volume overload (VO) induces significant stress on the heart, leading to cardiac dysfunction.
• Understanding how CS affects the stressed heart is crucial for cardiovascular health.

Purpose of the Study:

• To investigate the effects of cigarette smoke (CS) on the heart under volume overload (VO) stress.
• To determine if CS exacerbates VO-induced cardiac dysfunction by accelerating ventricular remodeling.

Main Methods:

• Male Sprague-Dawley rats underwent surgical induction of VO via abdominal aortocaval fistula (ACF).
• Rats were exposed to room air or CS (6 cigarettes/day) for 6 weeks.
• Echocardiography, morphological analysis of collagen, and assessment of cardiac protein expression (MMP-9, TIMP-1, HIF-1α, VEGF, TGF-β) were performed.

Main Results:

• CS significantly increased VO-induced left ventricular dilatation and depressed fractional shortening.
• CS prevented compensatory wall thickening and blunted compensatory collagen expression.
• CS exacerbated MMP-9 and TIMP-1 expression while blocking compensatory increases in HIF-1α, VEGF, and TGF-β.

Conclusions:

• Cigarette smoke (CS) worsens volume overload (VO)-induced cardiac remodeling and dysfunction.
• CS disrupts compensatory mechanisms in the heart, promoting eccentric dilation and impaired function.
• These findings highlight the detrimental impact of smoking on compromised cardiovascular systems.