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- Title
Fructose Modulates Cardiomyocyte Excitation- Contraction Coupling and Ca2+ Handling In Vitro.
- Authors
Mellor, Kimberley M.; Bell, James R.; Wendt, Igor R.; Davidoff, Amy J.; Ritchie, Rebecca H.; Delbridge, Lea M. D.
- Abstract
Background: High dietary fructose has structural and metabolic cardiac impact, but the potential for fructose to exert direct myocardial action is uncertain. Cardiomyocyte functional responsiveness to fructose, and capacity to transport fructose has not been previously demonstrated. Objective: The aim of the present study was to seek evidence of fructose-induced modulation of cardiomyocyte excitationcontraction coupling in an acute, in vitro setting. Methods and Results: The functional effects of fructose on isolated adult rat cardiomyocyte contractility and Ca2+ handling were evaluated under physiological conditions (37uC, 2 mM Ca2+, HEPES buffer, 4 Hz stimulation) using video edge detection and microfluorimetry (Fura2) methods. Compared with control glucose (11 mM) superfusate, 2-deoxyglucose (2 DG, 11 mM) substitution prolonged both the contraction and relaxation phases of the twitch (by 16 and 36% respectively, p,0.05) and this effect was completely abrogated with fructose supplementation (11 mM). Similarly, fructose prevented the Ca2+ transient delay induced by exposure to 2 DG (time to peak Ca2+ transient: 2 DG: 29.062.1 ms vs. glucose: 23.661.1 ms vs. fructose +2 DG: 23.761.0 ms; p,0.05). The presence of the fructose transporter, GLUT5 (Slc2a5) was demonstrated in ventricular cardiomyocytes using real time RT-PCR and this was confirmed by conventional RT-PCR. Conclusion: This is the first demonstration of an acute influence of fructose on cardiomyocyte excitation-contraction coupling. The findings indicate cardiomyocyte capacity to transport and functionally utilize exogenously supplied fructose. This study provides the impetus for future research directed towards characterizing myocardial fructose metabolism and understanding how long term high fructose intake may contribute to modulating cardiac function.
- Subjects
FRUCTOSE; HEART cells; CALCIUM ions; DIETARY supplements; LABORATORY rats; HEART ventricles; REVERSE transcriptase polymerase chain reaction
- Publication
PLoS ONE, 2011, Vol 6, Issue 9, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0025204