SERCA Pump Level is a Critical Determinant of Ca2+Homeostasis and Cardiac Contractility

2001 ◽  
Vol 33 (6) ◽  
pp. 1053-1063 ◽  
Author(s):  
Muthu Periasamy ◽  
Sabine Huke
Keyword(s):  
Cardiac Contractility ◽  
Pump Level ◽  
Critical Determinant ◽  
Serca Pump

scholarly journals Variability in Interbeat Duration Influences Myocardial Contractility in Rat Cardiac Trabeculae

2008 ◽  
Vol 2 (1) ◽  
pp. 100-104 ◽  
Author(s):  
Carlos A. A Torres ◽  
Kenneth D Varian ◽  
Paul M. L Janssen
Keyword(s):  
Heart Rate ◽  
Positive Inotropic Effect ◽  
Cardiac Contractility ◽  
Calcium Transients ◽  
Fixed Rate ◽  
Average Force ◽  
Critical Determinant ◽  
Before And After ◽  
Series Of Experiments ◽  
The Right

There is an intense search for positive inotropic strategies. It is well known that the interbeat duration is a critical determinant of cardiac contractility. Generally, when frequency increases, so does contractile strength. We hypothesize that the beat-to-beat variability at a given heart rate also modulates cardiac contractility. To test this hypothesis, thin, uniform rat cardiac trabeculae were isolated from the right ventricle and stimulated to isometrically contract, alternating between fixed steady state versus variable inter-beat intervals (same total number of beats in each period). Trabeculae were stimulated at 4 Hz with interbeat variation between 20 and 120% (n=17). In a second series of experiments trabeculae were stimulated at 3 different physiologic frequencies with a 40% interbeat variation. Fixed rate response was measured before and after each variable period and average force was calculated. In order to investigate the mechanism underlying the changes in contractility we used iontophoretically loaded bis-fura-2 salt to monitor intracellular calcium transients. We observed no significant change in force at 4 Hz (n=17), and 6 Hz (n=6) between fixed and variable pacing but observed a significant, 10% increase in contractile strength at 8 Hz (from 15.1 to 16.5 mN/mm2, p<0.05, n=6). Our results show that under certain conditions, by simply introducing variation in the beat-to-beat duration without affecting the number of beats per minute, a positive inotropic effect with corresponding changes in the calcium transients can be generated.

scholarly journals Cardiomyocytes stimulate angiogenesis after ischemic injury in a ZEB2-dependent manner

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Monika M. Gladka ◽  
Arwa Kohela ◽  
Bas Molenaar ◽  
Danielle Versteeg ◽  
Lieneke Kooijman ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Contractility ◽  
Ischemic Injury ◽  
Endothelial Cell Migration ◽  
Dependent Manner ◽  
Critical Determinant ◽  
Paracrine Factors ◽  
In Vivo Models ◽  
Prothymosin Α

AbstractThe disruption in blood supply due to myocardial infarction is a critical determinant for infarct size and subsequent deterioration in function. The identification of factors that enhance cardiac repair by the restoration of the vascular network is, therefore, of great significance. Here, we show that the transcription factor Zinc finger E-box-binding homeobox 2 (ZEB2) is increased in stressed cardiomyocytes and induces a cardioprotective cross-talk between cardiomyocytes and endothelial cells to enhance angiogenesis after ischemia. Single-cell sequencing indicates ZEB2 to be enriched in injured cardiomyocytes. Cardiomyocyte-specific deletion of ZEB2 results in impaired cardiac contractility and infarct healing post-myocardial infarction (post-MI), while cardiomyocyte-specific ZEB2 overexpression improves cardiomyocyte survival and cardiac function. We identified Thymosin β4 (TMSB4) and Prothymosin α (PTMA) as main paracrine factors released from cardiomyocytes to stimulate angiogenesis by enhancing endothelial cell migration, and whose regulation is validated in our in vivo models. Therapeutic delivery of ZEB2 to cardiomyocytes in the infarcted heart induces the expression of TMSB4 and PTMA, which enhances angiogenesis and prevents cardiac dysfunction. These findings reveal ZEB2 as a beneficial factor during ischemic injury, which may hold promise for the identification of new therapies.

Prolonged Exposure to Microgravity Reduces Cardiac Contractility and Initiates Remodeling in Drosophila

2020 ◽  
Author(s):  
Stanley Mark Walls ◽  
Soda Diop ◽  
Ryan Birse ◽  
Lisa Elmen ◽  
Zhouhui Gan ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
Cardiac Contractility
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