Figure 1.
Effect of heart-specific MTP-A-deficiency in chow-fed mice.
Mttpflox/flox mice were bred with Mck-Cre+/o mice to generate mice with heart-specific MTP-A-deficiency. A) Cre mRNA expression in liver (n = 4) and heart (n = 4) of Mttpflox/floxMck-Cre+/o mice, B) MTP-A mRNA expression in the liver (n = 4 in each group) and heart (n = 8 in each group) of Mttpflox/flox and Mttpflox/floxMck-Cre+/o mice, C) Total MTP mRNA expression in the heart of Mttpflox/flox (n = 8) and Mttpflox/floxMck-Cre+/o mice (n = 8), D) Cardiac MTP-B mRNA expression in Mttpflox/flox (n = 8) and Mttpflox/floxMck-Cre+/o mice (n = 8), E) Cardiac MTP activity Mttpflox/flox (n = 6) and Mttpflox/floxMck-Cre+/o mice (n = 6), F) Cardiac triglycerides in Mttpflox/flox (n = 8) and Mttpflox/floxMck-Cre+/o mice (n = 8). Open bars: Mttpflox/flox mice and closed bars: Mttpflox/floxMck-Cre+/o mice. Values are mean±SEM. The p values for two-group comparisons are: ** P<0.01; *** P<0.005 compared to chow-fed controls.
Figure 2.
Effect of heart-specific MTP-A deficiency on cardiac lipid accumulation and MTP activity in fasted mice and fat-fed obese mice.
A) cardiac triglycerides in mice that were fasted for 18 hours and mice that were fat-fed for three months (n = 7–9 in each group). *P<0.05 compared to Mttpflox/flox mice. B) MTP activity in fasted versus chow-fed mice (n = 6 in each group). **P<0.01 compared to fed mice, ‡ P<0.01 fasted Mttpflox/flox compared to fasted Mttpflox/floxMck-Cre+/o mice A+B) Open bars: Mttpflox/flox mice and closed bars: Mttpflox/floxMck-Cre+/o mice. C) MTP-A and MTP-B mRNA expression in fat-fed (closed bars) versus chow-fed (open bars) Mttpflox/flox mice (n = 7 in each group). **P<0.01 and ***P<0.005 compared to chow-fed Mttpflox/flox mice. D) MTP-A and MTP-B mRNA expression in fat-fed (closed bars) versus chow-fed (open bars) Mttpflox/floxMck-Cre+/o mice (n = 7 in each group). Values are mean±SEM.
Figure 3.
Effect of heart-specific MTP-A deficiency on insulin-stimulated glucose uptake and expression of lipid metabolizing genes in obese mouse heart.
The effect of heart-specific MTP-A deletion on A) insulin-stimulated glucose uptake in cardiac ventricles, B) skeletal muscle, and C) epididymal fat was determined after 3 months of fat-feeding. D) Cardiac mRNA expression was quantified with real-time PCR in fat-fed male Mttpflox/flox mice, Mttpflox/floxMck-Cre+/o mice and their lean controls. Values are after 3 months of diet. Open bars: chow-fed Mttpflox/flox mice (n = 7–8), closed bars: fat-fed Mttpflox/flox mice (n = 7–8), hatched bars: chow-fed Mttpflox/floxMck-Cre+/o mice (n = 7–8), squared bars: fat-fed Mttpflox/floxMck-Cre+/o mice (n = 7). Values are mean±SEM. The p values for two-group comparisons are: * P<0.05, ** P<0.01; *** P<0.005 compared to chow-fed controls; ‡ P<0.01 compared to fat-fed Mttpflox/floxMck-Cre+/o mice.
Figure 4.
Overexpression of human apoB in the heart affects cardiac triglyceride levels as well as expression of genes involved in cardiac stress and metabolism of free fatty acids in fat-fed C57Bl/6 mice.
The effect of cardiac overexpression of a human apoB-transgene in obese mice on A) cardiac triglycerides were determined using TLC, B) cardiac mRNA expression of lipid metabolising genes and C) cardiac mRNA expression of stress-related genes was quantified with real-time PCR in male fat-fed C57Bl/6 (n = 11) and C57Bl/6-apoB-Tg mice (n = 9) and their lean controls (n = 6). Values are after 12 months of diet. Open bars: chow-fed C57Bl/6 mice, closed bars: fat-fed C57Bl/6 mice, hatched bars: chow-fed C57Bl/6-apoB-Tg mice, squared bars: fat-fed C57Bl/6-apoB-Tg mice. Values are mean±SEM. The p values for two-group comparisons are: * P<0.05, ** P<0.01; *** P<0.005 compared to chow-fed controls; ‡ P<0.05 Fat-fed C57Bl/6 compared to fat-fed C57Bl/6-apoB-Tg.
Figure 5.
Overexpression of human apoB in the heart attenuates deterioration of cardiac function in fat-fed obese mice.
Heart function was determined with a conductance catheter placed in the left cardiac ventricle A) EF, ejection fraction, B) PRSW, preload recruitable stroke work. Open bars: chow-fed C57Bl/6 mice (n = 7), closed bars: fat-fed C57Bl/6 mice (n = 7), hatched bars: chow-fed C57Bl/6-apoB-Tg mice (n = 11), squared bars: fat-fed C57Bl/6-apoB-Tg mice (n = 7). Values are mean±SEM after 11 months on the diets. The p values for two-group comparisons are: * P<0.05, ** P≤0.01.