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In vivo assessment of cardiac metabolism and function in the abdominal aortic banding model of compensated cardiac hypertrophy.

Seymour AM, Giles L, Ball V, Miller JJ, Clarke K, Carr CA, Tyler DJ - Cardiovasc. Res. (2015)

Bottom Line: Pyruvate dehydrogenase flux was unchanged in the hypertrophied animals at any time point, but increased incorporation of the (13)C label into lactate was observed by 9 weeks and maintained at 14 weeks, indicative of enhanced glycolysis.Hypertrophied hearts revealed little evidence of a switch towards increased glucose oxidation but rather an uncoupling of glycolytic metabolism from glucose oxidation.This was maintained under conditions of dietary stress provided by a WD but, at this compensated phase of hypertrophy, did not result in any contractile dysfunction.

View Article: PubMed Central - PubMed

Affiliation: School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull HU6 7RX, UK.

No MeSH data available.


Related in: MedlinePlus

Cardiac hyperpolarized 13C signal localization is achieved via the high local sensitivity of the RF surface coil used and the high metabolic rate of the heart relative to other organs/tissues within the sensitive region of the coil (A, LV, left ventricular lumen; RV, right ventricular lumen; myo, myocardial tissue). This figure, acquired with a 3D spectral-spatial, echo planar spectroscopic imaging sequence [matrix: 32 × 32 × 12, field of view: 64 × 64 × 45.5 mm3, acquired resolution: 2 × 2 × 4 mm3, echo time (TE): 16.3 ms, repetition time (TR): 1RR interval (≈150 ms); flip angle: 17° pyruvate/61°bicarbonate], demonstrates that the pyruvate signal (B) originates primarily from the blood in the chambers of the heart, while the downstream metabolic signals, in this example bicarbonate (C), are originating from the front wall of the left ventricle.
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Figure 1: Cardiac hyperpolarized 13C signal localization is achieved via the high local sensitivity of the RF surface coil used and the high metabolic rate of the heart relative to other organs/tissues within the sensitive region of the coil (A, LV, left ventricular lumen; RV, right ventricular lumen; myo, myocardial tissue). This figure, acquired with a 3D spectral-spatial, echo planar spectroscopic imaging sequence [matrix: 32 × 32 × 12, field of view: 64 × 64 × 45.5 mm3, acquired resolution: 2 × 2 × 4 mm3, echo time (TE): 16.3 ms, repetition time (TR): 1RR interval (≈150 ms); flip angle: 17° pyruvate/61°bicarbonate], demonstrates that the pyruvate signal (B) originates primarily from the blood in the chambers of the heart, while the downstream metabolic signals, in this example bicarbonate (C), are originating from the front wall of the left ventricle.

Mentions: At 4, 9, and 14 weeks post-surgery, rats received an intravenous injection of either [1-13C]pyruvate together with blood sampling from the saphenous vein or [2-13C]pyruvate together with a CINE MRI investigation to determine cardiac morphology and function. Anaesthesia was induced by 2.5–3% isofluorane in oxygen and nitrous oxide (O2:N2O 4:1, total of 2 L/min). The adequacy of anaesthesia was initially assessed based on the loss of the pedal response and was then continuously monitored through the evaluation of the heart and respiration rates. Anaesthesia was maintained by means of 2% isofluorane delivered during the experiment (O2:N2O 4:1, total of 2 L/min). A tail vein cannulation for i.v. administration of hyperpolarized solutions was performed before the animals were subsequently placed in a home-built MR animal handling system.17 The ECG, respiration rate, and body temperature were monitored throughout the experiment, and air heating was provided to maintain the body temperature at 37°C as previously described.18 A home-built 1H/13C butterfly surface coil (loop diameter, 20 mm) was placed over the rat chest, localizing the signal from the heart due to the high local sensitivity of the surface coil and the high metabolic rate of the heart (Figure 1). The animal was positioned with the heart at iso-centre in a horizontal bore 7 T MR scanner interfaced to a direct-drive console (Varian Inc., Yarnton, UK) and correct positioning was confirmed by the acquisition of an axial proton fast low-angle shot (FLASH) image. An ECG-gated shim was used to reduce the proton line width to ~120 Hz.16 Animals were allowed to recover fully from anaesthesia for serial MR investigations.


In vivo assessment of cardiac metabolism and function in the abdominal aortic banding model of compensated cardiac hypertrophy.

Seymour AM, Giles L, Ball V, Miller JJ, Clarke K, Carr CA, Tyler DJ - Cardiovasc. Res. (2015)

Cardiac hyperpolarized 13C signal localization is achieved via the high local sensitivity of the RF surface coil used and the high metabolic rate of the heart relative to other organs/tissues within the sensitive region of the coil (A, LV, left ventricular lumen; RV, right ventricular lumen; myo, myocardial tissue). This figure, acquired with a 3D spectral-spatial, echo planar spectroscopic imaging sequence [matrix: 32 × 32 × 12, field of view: 64 × 64 × 45.5 mm3, acquired resolution: 2 × 2 × 4 mm3, echo time (TE): 16.3 ms, repetition time (TR): 1RR interval (≈150 ms); flip angle: 17° pyruvate/61°bicarbonate], demonstrates that the pyruvate signal (B) originates primarily from the blood in the chambers of the heart, while the downstream metabolic signals, in this example bicarbonate (C), are originating from the front wall of the left ventricle.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400188&req=5

Figure 1: Cardiac hyperpolarized 13C signal localization is achieved via the high local sensitivity of the RF surface coil used and the high metabolic rate of the heart relative to other organs/tissues within the sensitive region of the coil (A, LV, left ventricular lumen; RV, right ventricular lumen; myo, myocardial tissue). This figure, acquired with a 3D spectral-spatial, echo planar spectroscopic imaging sequence [matrix: 32 × 32 × 12, field of view: 64 × 64 × 45.5 mm3, acquired resolution: 2 × 2 × 4 mm3, echo time (TE): 16.3 ms, repetition time (TR): 1RR interval (≈150 ms); flip angle: 17° pyruvate/61°bicarbonate], demonstrates that the pyruvate signal (B) originates primarily from the blood in the chambers of the heart, while the downstream metabolic signals, in this example bicarbonate (C), are originating from the front wall of the left ventricle.
Mentions: At 4, 9, and 14 weeks post-surgery, rats received an intravenous injection of either [1-13C]pyruvate together with blood sampling from the saphenous vein or [2-13C]pyruvate together with a CINE MRI investigation to determine cardiac morphology and function. Anaesthesia was induced by 2.5–3% isofluorane in oxygen and nitrous oxide (O2:N2O 4:1, total of 2 L/min). The adequacy of anaesthesia was initially assessed based on the loss of the pedal response and was then continuously monitored through the evaluation of the heart and respiration rates. Anaesthesia was maintained by means of 2% isofluorane delivered during the experiment (O2:N2O 4:1, total of 2 L/min). A tail vein cannulation for i.v. administration of hyperpolarized solutions was performed before the animals were subsequently placed in a home-built MR animal handling system.17 The ECG, respiration rate, and body temperature were monitored throughout the experiment, and air heating was provided to maintain the body temperature at 37°C as previously described.18 A home-built 1H/13C butterfly surface coil (loop diameter, 20 mm) was placed over the rat chest, localizing the signal from the heart due to the high local sensitivity of the surface coil and the high metabolic rate of the heart (Figure 1). The animal was positioned with the heart at iso-centre in a horizontal bore 7 T MR scanner interfaced to a direct-drive console (Varian Inc., Yarnton, UK) and correct positioning was confirmed by the acquisition of an axial proton fast low-angle shot (FLASH) image. An ECG-gated shim was used to reduce the proton line width to ~120 Hz.16 Animals were allowed to recover fully from anaesthesia for serial MR investigations.

Bottom Line: Pyruvate dehydrogenase flux was unchanged in the hypertrophied animals at any time point, but increased incorporation of the (13)C label into lactate was observed by 9 weeks and maintained at 14 weeks, indicative of enhanced glycolysis.Hypertrophied hearts revealed little evidence of a switch towards increased glucose oxidation but rather an uncoupling of glycolytic metabolism from glucose oxidation.This was maintained under conditions of dietary stress provided by a WD but, at this compensated phase of hypertrophy, did not result in any contractile dysfunction.

View Article: PubMed Central - PubMed

Affiliation: School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull HU6 7RX, UK.

No MeSH data available.


Related in: MedlinePlus