Myriocin treatment of DIO mice decreases intra-myocardial ceramide levels and prevents the accumulation of intra-myocardial DAG.

<p><i>A:</i> Intra-myocardial TAG, <i>B:</i> ceramide, <i>C:</i> long chain acyl CoA, and <i>D:</i> DAG levels in low fat fed and DIO mice treated with vehicle control or myriocin. Values represent mean ± SE (n = 4–8). Differences were determined using a one-way ANOVA followed by Bonferroni post-hoc analysis. *<i>P</i><0.05, significantly different from vehicle control counterpart. ^†<i>P</i><0.05, significantly different from low fat fed counterpart.</p

Myriocin treatment of <i>db/db</i> mice decreases intra-myocardial ceramide levels but has no effect on intra-myocardial DAG content.

<p><i>A:</i> Intra-myocardial ceramide, and <i>B:</i> DAG levels in <i>db/db</i> mice treated with vehicle control or myriocin. Values represent mean ± SE (n = 4–6). Differences were determined using an unpaired Student’s two-tailed t-test. *<i>P</i><0.05, significantly different from vehicle control counterpart.</p

SPT I inhibition improves myocardial glycolysis rates in DIO mice.

<p><i>A:</i> DIO impairs insulin-stimulated glycolysis rates in hearts from control treated mice, which was improved in hearts from myriocin treated DIO mice. <i>B:</i> Rates of glucose oxidation in hearts from control and myriocin treated low fat fed and DIO mice. Values represent mean ± SE (n = 6–7). Differences were determined using a one-way ANOVA followed by a Bonferroni’s post-hoc analysis. *<i>P</i><0.05, significantly different from low fat fed counterpart. ^†<i>P</i><0.05, significantly different from DIO control.</p

Cardiac PDH activity is not impaired in DIO mice treated with myriocin.

<p><i>A:</i> Cardiac PDH activity in control and myriocin treated DIO Mice. <i>B:</i> % decrease in cardiac PDH activity relative to low fat fed counterparts. <i>C</i>: Cardiac PDK4 protein expression is increased in control treated DIO mice, but not myriocin treated DIO mice. Values represent mean ± SE (n = 6). Differences were determined using an unpaired Student’s two-tailed t-test or a one-way ANOVA followed by a Bonferroni’s post-hoc analysis. *<i>P</i><0.05, significantly different from DIO control mice. ^†<i>P</i><0.05, significantly different from low fat fed counterpart.</p

Cardiac Akt phosphorylation in increased in myriocin treated DIO mice.

<p>Isolated working mouse hearts were perfused aerobically in the presence of insulin (100 µU/mL ) for determination of, <i>A:</i> Cardiac Akt serine 473 phosphorylation, <i>B:</i> GSK3β serine 9 phosphorylation, and <i>C:</i> AMPK threonine 172 phosphorylation in low fat fed and DIO mice treated with control or myriocin <i>D:</i> Cardiac Akt serine 473 phosphorylation, GSK3β serine 9 phosphorylation, AMPK threonine 172 phosphorylation, and PDK4 expression in control and myriocin treated <i>db/db</i> mouse hearts. Values represent mean ± SE (n = 4–7). Differences were determined using an unpaired Student’s two-tailed t-test or a one-way ANOVA followed by Bonferroni post-hoc analysis. *<i>P</i><0.05, significantly different from DIO control treated mice. ^†<i>P</i> = 0.06.</p

Cardiac malonyl CoA levels (nmol/g dry weight).

<p>Cardiac malonyl CoA content was measured in WT mice fed a low or high fat diet and treated with vehicle control or myriocin (n = 5–6). Values represent means ± SE.</p

Plasma Lipids in DIO and <i>db/db</i> mice.

<p>Plasma TAG and FFA levels ad libitum were measured in DIO and <i>db/db</i> mice treated with vehicle control or myriocin (n = 4–7). Values represent means ± SE.</p

H⁺ production in hearts from DIO mice.

<p>H⁺ production was calculated in control and myriocin treated DIO mice by subtracting the rate of glucose oxidation from the rate of glycolysis and multiplying by two. Values represent mean ± SE (n = 6–7). Differences were determined using an unpaired Student’s two-tailed t-test. *<i>P</i> = 0.13.</p

Insulin resistance in mice following DIO.

<p><i>A:</i> 12 weeks of DIO results in significant increases in body weight in mice. <i>B:</i> This increase in body weight resulted in whole body glucose intolerance, and <i>C:</i> insulin resistance. Values represent mean ± SE (n = 10–11). Glucose and insulin were administered via intraperitoneal injection. Differences were determined using an unpaired Student’s two-tailed t-test or two-way ANOVA followed by a Bonferroni’s post-hoc analysis. *<i>P</i><0.05, significantly different from low fat fed counterpart. ^†<i>P</i><0.05, significantly different from low fat fed counterpart at 12 weeks post-diet.</p

Cardiac function and left ventricular wall measurements in <i>db/db</i> mice treated with myriocin.

<p><i>In vivo</i> cardiac function and ventricular wall measurements were assessed via echocardiography in isoflurane anesthetized <i>db/db</i> mice treated with vehicle control or myriocin (n = 5). Values represent means ± SE. LVPW = left ventricular posterior wall, LVID = left ventricular internal diameter, IVS = intraventricular septum, d = diastole, s = systole.</p