| Autor: |
Murali M; Department of Biochemistry & Molecular Biology, Cumming School of Medicine,University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada., Turner SR; Department of Biochemistry & Molecular Biology, Cumming School of Medicine,University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada., Belke DD; Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, 1403-29 Street NWCalgary, AB T2N 2T9, Canada., Cole WC; Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada., MacDonald JA; Department of Biochemistry & Molecular Biology, Cumming School of Medicine,University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada. |
| Abstrakt: |
Smoothelin-like 1 (SMTNL1) modulates the contractile performance of smooth muscle and thus has a key role in vascular homeostasis. Elevated vascular tone, recognized as a contributor to the development of progressive cardiac dysfunction, was previously found with SMTNL1 deletion. In this study, we assessed cardiac morphology and function of male and female, wild-type ( Smtnl1 +/+ ) and global SMTNL1 knockout ( Smtnl1 -/- ) mice at 10 weeks of age. Gross dissection revealed distinct cardiac morphology only in males; Smtnl1 -/- hearts were significantly smaller than Smtnl1 +/+ , but the left ventricle (LV) proportion of heart mass was greater. Male Smtnl1 -/- mice also displayed increased ejection fraction and fractional shortening, as well as elevated aortic and pulmonary flow velocities. The impact of cardiac stress with pressure overload by transverse aortic constriction (TAC) was examined in male mice. With TAC banding, systolic function was preserved, but the LV filling pressure was selectively elevated due to relaxation impairment. Smtnl1 -/- mice displayed higher early/passive filling velocity of LV/early mitral annulus velocity ratio (E/E' ratio) and myocardial performance index along with a prolonged isovolumetric relaxation time. Taken together, the findings support a novel, sex-dimorphic role for SMTNL1 in modulating cardiac structure and function of mice. |
