Influence of Taurine on Cardiac Remodeling Induced by Tobacco Smoke Exposure
Background/Aims: To investigate the effect of taurine on cardiac remodeling induced by smoking. Methods: In the first step, rats were allocated into two groups: Group C (n=14): control; Group T (n=14): treated with taurine (3% in drinking water), for three months. In the second step, rats were allocated into two groups: Group ETS (n=9): rats exposed to tobacco smoke; Group ETS-T (n=9): rats exposed to tobacco smoke and treated with taurine for two months. Results: After three months, taurine presented no effects on morphological or functional variables of normal rats assessed by echocardiogram. On the other hand, after two months, ETS-T group presented higher LV wall thickness (ETS=1.30 (1.20-1.42); ETS-T=1.50 (1.40-1.50); p=0.029), E/A ratio (ETS=1.13±0.13; ETS-T=1.37±0.26; p=0.028), and isovolumetric relaxation time normalized for heart rate (ETS=53.9±4.33; ETS-T=72.5±12.0; p<0.001). The cardiac activity of the lactate dehydrogenase was higher in the ETS-T group (ETS=204±14 nmol/mg protein; ETS-T=232±12 nmol/mg protein; p<0.001). ETS-T group presented lower levels of phospholamban (ETS=1.00±0.13; ETS-T=0.82±0.06; p=0.026), phosphorylated phospholamban at Ser16 (ETS=1.00±0.14;ETS-T=0.63±0.10;p=0.003), and phosphorylated phosfolamban/phospholamban ratio (ETS=1.01±0.17; ETS-T=0.77±0.11; p=0.050). Conclusion: In normal rats, taurine produces no effects on cardiac morphological or functional variables. On the other hand, in rats exposed to cigarette smoke, taurine supplementation increases wall thickness and worsens diastolic function, associated with alterations in calcium handling protein and cardiac energy metabolism.