Comparison of metabolic and functional parameters using cardiac 18F-FDG-PET in early to mid-adulthood male and female mice

Abstract

Background In this descriptive study of male and female mice at different weeks of age, we use serial non-invasive cardiac 18F-FDG-PET scans to follow up on metabolic alterations, heart function parameters, and the ECG of both sexes in early to mid-adulthood. Methods ECG-gated 18F-FDG-PET scans were performed in mice on 10, 14, and 18 weeks of age, using a dedicated small-animal PET scanner. The percentage of the injected activity per gram (%IA/g) in the heart, left ventricular metabolic volume (LVMV), myocardial viability and left ventricular function parameters: end-diastolic (EDV), end-systolic (ESV), stroke volume (SV), and the ejection fraction (EF%) were estimated. Results Compared to their age-matched female counterpart, male mice showed a constant increase in LVMV and ventricular volume during the follow-up. In contrast, female mice remain stable after ten weeks of age. Furthermore, male mice showed lower heart rates, positive correlation with cardiac %IA/g, and negative correlation with LVMV. Conclusion In this study of serial cardiac PET scans, we provide insight for basic murine research models, showing that mice gender and age show distinct cardiac metabolisms. These physiologic alterations need to be considered when planning in vivo injury models to avoid potential pitfalls.

Visualizing increased uptake of [18F]FDG and [18F]FTHA in kidneys from obese high-fat diet fed C57BL/6J mice using PET/CT ex vivo

“…Since uptake of FDG in the mouse heart has been more thoroughly studied [ 28 ], we used hearts from the same animals for comparison. When comparing FDG uptake in hearts between ad libitum fed ( Fig 3A ), and fasted ( Fig 3B ) young mice, a significantly higher SUV-value was found in the ad libitum fed state (2.2 times higher, p<0.01).…”

“…Our first aim was to address some of the limitations [ 27 ], and develop a PET/CT protocol to detect and compare changes in uptake of FDG and [ 18 F]FTHA (FTHA) in mouse kidneys. For comparison we studied uptake of the tracers in hearts, since the heart has been studied to a greater extent in the past [ 28 , 29 ]. Our ex vivo PET/CT protocol enabled us to further study uptake of FDG and FTHA in kidneys of mice under different metabolic challenges (feeding/fasting, HFD or old age) to detect possible shifts and changes in energy substrate preferences.…”

Cardiac 18F-FDG Positron Emission Tomography: An Accurate Tool to Monitor In vivo Metabolic and Functional Alterations in Murine Myocardial Infarction

“…Correct VOI placement was verified in three projections (axial, sagittal, and coronal) ( 12 ). Our previous publication ( 24 ) shows that LVMV depends on mice age, and there are significant differences between 10 and 18 weeks old mice. We could not detect this aspect in the evaluation of %ID/g.…”

“…Previous work demonstrated a cardiac growth dependency in mice from early to mid-adulthood ( 24 ). The LVMV, estimating the cardiac mass ( 12 ) in mice, rises from 10 to 18 weeks and the ESV and EF changes over time.…”

“…We could not detect this aspect in the evaluation of %ID/g. The male age-matched control mice partially derive from a healthy murine database that was acquired during the same period ( 24 ).…”