Optical Metabolic Imaging of Mitochondrial Dysfunction on HADH Mutant Newborn Rat Hearts

Age-dependent differences in the effects of ischemia and reperfusion on ATP breakdown were studied in perfused adult and newborn (10 days old) rat hearts. No-flow ischemia (15 min at 37, 30, or 23 degrees C) was applied and reperfusion (20 min at 37 degrees C) was studied after ischemia at 23 or 37 degrees C. Hypothermia during ischemia protected both age groups to a similar degree against ATP decline, which was linear with temperature. Reperfusion after normothermic ischemia resulted in higher ATP levels in newborn hearts with less release of ATP catabolites (purines). We found no age-related differences in lactate release but large differences in purine release. During normoxia, adult hearts released mainly urate (80% of total) and inosine (7%), but newborns released hypoxanthine (64%) and inosine (15%). Early during reperfusion adult hearts released inosine (58%) and adenosine (18%), but newborns released inosine (53%) and hypoxanthine (38%). These data suggested a lower activity of the potentially deleterious enzyme xanthine oxidoreductase in newborn hearts, which was confirmed by enzymatic assay. ATP-catabolite release during reperfusion was less in newborn than adult hearts, and this coincided with lower xanthine oxidase activity.

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Transmural differences in respiratory capacity across the rat left ventricle in health, aging, and streptozotocin-induced diabetes mellitus: evidence that mitochondrial dysfunction begins in the subepicardium

AJP Cell Physiology ◽

10.1152/ajpcell.00294.2010 ◽

2011 ◽

Vol 300 (2) ◽

pp. C246-C255 ◽

Cited By ~ 11

Author(s):

J. R. MacDonald ◽

M. Oellermann ◽

S. Rynbeck ◽

G. Chang ◽

K. Ruggiero ◽

...

Keyword(s):

Heart Rate ◽

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Streptozotocin Diabetes ◽

Left Ventricular ◽

Diabetic Rat ◽

Rat Hearts ◽

Myocardial Layers ◽

Streptozotocin Induced Diabetes ◽

Old Rats

In diabetic cardiomyopathy, ventricular dysfunction occurs in the absence of hypertension or atherosclerosis and is accompanied by altered myocardial substrate utilization and depressed mitochondrial respiration. It is not known if mitochondrial function differs across the left ventricular (LV) wall in diabetes. In the healthy heart, the inner subendocardial region demonstrates higher rates of blood flow, oxygen consumption, and ATP turnover compared with the outer subepicardial region, but published transmural respirometric measurements have not demonstrated differences. We aim to measure mitochondrial function in Wistar rat LV to determine the effects of age, streptozotocin-diabetes, and LV layer. High-resolution respirometry measured indexes of respiration in saponin-skinned fibers dissected from the LV subendocardium and subepicardium of 3-mo-old rats after 1 mo of streptozotocin-induced diabetes and 4-mo-old rats following 2 mo of diabetes. Heart rate and heartbeat duration were measured under isoflurane-anesthesia using a fetal-Doppler, and transmission electron microscopy was employed to observe ultrastructural differences. Heart rate decreased with age and diabetes, whereas heartbeat duration increased with diabetes. While there were no transmural respirational differences in young healthy rat hearts, both myocardial layers showed a respiratory depression with age (30–40%). In 1-mo diabetic rat hearts only subepicardial respiration was depressed, whereas after 2 mo diabetes, respiration in subendocardial and subepicardial layers was depressed and showed elevated leak (state 2) respiration. These data provide evidence that mitochondrial dysfunction is first detectable in the subepicardium of diabetic rat LV, whereas there are measureable changes in LV mitochondria after only 4 mo of aging.

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Metabolic imaging with the use of fluorescence lifetime imaging microscopy (FLIM) accurately detects mitochondrial dysfunction in mouse oocytes

Fertility and Sterility ◽

10.1016/j.fertnstert.2018.07.022 ◽

2018 ◽

Vol 110 (7) ◽

pp. 1387-1397 ◽

Cited By ~ 17

Author(s):

Tim Sanchez ◽

Tianren Wang ◽

Marta Venturas Pedro ◽

Man Zhang ◽

Ecem Esencan ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Fluorescence Lifetime ◽

Metabolic Imaging ◽

Fluorescence Lifetime Imaging Microscopy ◽

Fluorescence Lifetime Imaging ◽

Lifetime Imaging ◽

Mouse Oocytes

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Leptin Modifies the Rat Heart Performance Associated with Mitochondrial Dysfunction Independently of Its Prohypertrophic Effects

International Journal of Endocrinology ◽

10.1155/2018/6081415 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Edna Berzabá-Evoli ◽

Cecilia Zazueta ◽

Jarumi Hishel Cruz Hernández ◽

Nancy Patricia Gómez-Crisóstomo ◽

Isela Esther Juárez-Rojop ◽

...

Keyword(s):

Membrane Potential ◽

Cardiac Hypertrophy ◽

Mitochondrial Dysfunction ◽

Calcium Transport ◽

Respiratory Control ◽

Rate Pressure Product ◽

High Concentration ◽

Heart Performance ◽

Rat Hearts ◽

High Concentrations

Background. Functional receptors for leptin were described on the surface of cardiomyocytes, and there was a prohypertrophic effect with high concentrations of the cytokine. Therefore, leptin could be a link between obesity and the prevalence of cardiovascular diseases. On the other hand, a deleterious effect of leptin on mitochondrial performance was described, which was also associated with the evolution of cardiac hypertrophy to heart failure. The goal of our study was to analyze the effect of the exposure of rat hearts to a high concentration of leptin on cardiac and mitochondrial function. Methods. Rat hearts were perfused continuously with or without 3.1 nM leptin for 1, 2, 3, or 4 hours. Homogenates and mitochondria were prepared by centrifugation and analyzed for cardiac actin, STAT3, and pSTAT3 by Western blotting, as well as for mitochondrial oxidative phosphorylation, membrane potential, swelling, calcium transport, and content of oxidized lipids. Results. In our results, leptin induced an increased rate-pressure product as a result of increased heart rate and contraction force, as well oxidative stress. In addition, mitochondrial dysfunction expressed as a loss of membrane potential, decreased ability for calcium transport and retention, faster swelling, and less respiratory control was observed. Conclusions. Our results support the role of leptin as a deleterious factor for cardiac function and indicates that mitochondrial dysfunction could be a trigger for cardiac hypertrophy and failure.

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Maternal High Fat Diet and Diabetes Disrupts Transcriptomic Pathways that Regulate Cardiac Metabolism and Cell Fate in Newborn Rat Hearts

10.21203/rs.3.rs-30050/v1 ◽

2020 ◽

Author(s):

Claudia C. Preston ◽

Tricia D. Larsen ◽

Julie A. Eclov ◽

Eli J. Louwagie ◽

Tyler C. T. Gandy ◽

...

Keyword(s):

Gene Expression ◽

Cell Fate ◽

Cell Metabolism ◽

Maternal Diabetes ◽

Cardiac Metabolism ◽

Late Gestation ◽

Flux Analysis ◽

High Fat ◽

Newborn Rat ◽

Rat Hearts

Abstract Background Children born to diabetic or obese mothers have a higher risk of heart disease at birth and later in life. Our previous work using chromatin immunoprecipitation sequencing revealed that late-gestation diabetes in combination with maternal high fat (HF) diet cause a distinct fuel-mediated epigenetic reprogramming of rat cardiac tissue during fetal cardiogenesis. The objective of the present study was to investigate the overall transcriptional signature of newborn offspring exposed to the combination of maternal diabetes and maternal HF diet. Methods Gene expression profiling from hearts of diabetes exposed, HF diet exposed, combination exposed and control newborn rats was compared for differential transcriptome expression. Functional annotation, pathway and network analysis was performed on statistically significant differentially expressed genes from the combination exposed group compared with controls. Downstream metabolic assessments included measurement of total and phosphorylated AKT2 and GSK3β assays, as well as quantification of glycolytic capacity by extracellular flux analysis and glycogen staining. Results Transcriptome analysis of newborn rat hearts showed significant changes in cardiac gene expression following exposure to maternal diabetes or HF diet individually, as well as the combination of diabetes + HF compared with controls. Reactome analyses identified expression changes in two key signaling cascades functionally prioritized in male control and combination exposed offspring hearts. These pathways included downregulation of the fibroblast growth factor (FGF) pathway and concomitant downstream PI3K/AKT activation canonically recognized as a regulator of cell metabolism, growth, and development. In contrast, the second pathway exhibited significant upregulation of mitoribosomal signaling that regulates mitochondrial biogenesis, mitophagy and cell fate. Focused bioinformatic analysis on mitochondrial genes enriched in the combination exposed dataset revealed genes associated with diverse aspects of mitochondrial structure, function, and dynamism. Functional biochemical, metabolic, and histochemical assays supported these transcriptome changes, confirming the essential role of mitochondrial energetics in facilitating diabetes- and diet-induced cardiac transcriptome remodeling and phenotype in offspring. Conclusions This study provides the first data accounting for the compounding effects of maternal hyperglycemia and hyperlipidemia on the developmental cardiac transcriptome, and elucidates nuanced and novel features of maternal diabetes and diet on intergenerational regulation of heart health.

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Fatty acids and phospholipids of adult and newborn rat hearts and of cultured, beating neonatal rat myocardial cells

Lipids ◽

10.1007/bf02532502 ◽

1974 ◽

Vol 9 (8) ◽

pp. 541-547 ◽

Cited By ~ 24

Author(s):

C. G. Rogers

Keyword(s):

Fatty Acids ◽

Neonatal Rat ◽

Myocardial Cells ◽

Newborn Rat ◽

Rat Hearts

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Abstract 12881: Noninvasive In Vivo Assessment of Cardiac Metabolism in Dobutamine-stressed Ischemic Rat Hearts Using Hyperpolarized 13 C MRI

Circulation ◽

10.1161/circ.142.suppl_3.12881 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Gaurav Sharma ◽

Alexander Funk ◽

Xiaodong Wen ◽

Crystal Harrison ◽

Nesmine Maptue ◽

...

Keyword(s):

Oxidative Metabolism ◽

Cardiac Metabolism ◽

Dobutamine Stress ◽

Ischemic Myocardium ◽

Metabolic Imaging ◽

Imaging Method ◽

Adrenergic Stimulation ◽

Rat Hearts ◽

Volume Coil

Introduction and Hypothesis: Conventional metabolic imaging methods such as PET, dobutamine stress echo or late gadolinium enhancement do not directly detect the functional state of the critical organelle in oxidative metabolism, the mitochondrion. Hyperpolarized (HP) 13 C-metabolic imaging has been used to assess mitochondrial function in preclinical models and is an exciting new imaging method for evaluating the ischemic myocardium noninvasively. This study aims to evaluate myocardial response to dobutamine stress in ischemic rat hearts using HP-[1- 13 C]pyruvate. Methods: Metabolism of HP[1- 13 C]pyruvate was investigated in male SD rats in four groups: 1. normal myocardium (NM), 2. ischemic myocardium (IM), 3. NM+dobutamine, 4. IM+dobutamine. The myocardial ischemic model was developed by partial occlusion of the coronary artery as described in earlier studies by others. For dobutamine stress HP-MRS, intra-peritoneal injection of 1.5 mg/kg of dobutamine was administered before positioning the animal in the MRI scanner. 13 C data were acquired 7 days after the surgery in a 4.7 T MRI scanner using a Varian 60 mm dual-tuned 1 H/ 13 C linear volume coil. Anatomical 1 H images were acquired for slice planning and positioning. 13 C intensity maps were generated and displayed as overlays on grayscale 1 H images. In separate experiments, in vivo HP- 13 C-MRS data acquisition was initiated immediately after the pyruvate injection. Results: The HP signals from [1- 13 C]lactate, [1- 13 C]alanine, and 13 C-bicarbonate were detected in real-time 13 C spectra from hearts following injection of HP[1- 13 C]pyruvate. In hearts with partial coronary ligation, the MRS data were acquired from a mixture of ischemic and nonischemic myocardium. A 27% decrease in bicarbonate production was observed in hearts with ischemic myocardium compared to control hearts. After stimulation of NM hearts with dobutamine, less bicarbonate was produced from HP-pyruvate likely due to an increased contribution of other endogenous substrates to acetyl-CoA. Production of bicarbonate was unchanged in IM hearts following adrenergic stimulation. Conclusions: Our results demonstrated that decreased oxidative metabolism of pyruvate as a result of myocardial ischemia and dobutamine stress.

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