scholarly journals 1002-79 The peroxisome proliferator activated receptor-α activator, fenofibrate, improves recovery of left ventricular contractile function after ischemia and reperfusion in pigs

2004 ◽  
Vol 43 (5) ◽  
pp. A243
Author(s):  
Ya Xu ◽  
Michael Gen ◽  
Li Lu ◽  
Clifford Greyson ◽  
Carlin S Long ◽  
...  
2002 ◽  
Vol 283 (3) ◽  
pp. H949-H957 ◽  
Author(s):  
Ellen Aasum ◽  
Darrell D. Belke ◽  
David L. Severson ◽  
Rudolph A. Riemersma ◽  
Marie Cooper ◽  
...  

Hearts from diabetic db/ db mice, a model of Type 2 diabetes, exhibit left ventricular failure and altered metabolism of exogenous substrates. Peroxisome proliferator-activated receptor-α (PPAR-α) ligands reduce plasma lipid and glucose concentrations and improve insulin sensitivity in db/ db mice. Consequently, the effect of 4- to 5-wk treatment of db/ db mice with a novel PPAR-α ligand (BM 17.0744; 25–38 mg · kg−1 · day−1), commencing at 8 wk of age, on ex vivo cardiac function and metabolism was determined. Elevated plasma concentrations of glucose, fatty acids, and triacylglycerol (34.0 ± 3.6, 2.0 ± 0.4, and 0.9 ± 0.1 mM, respectively) were reduced to normal after treatment with BM 17.0744 (10.8 ± 0.6, 1.1 ± 0.1, and 0.6 ± 0.1 mM). Plasma insulin was also reduced significantly in treated compared with untreated db/ db mice. Chronic treatment of db/ db mice with the PPAR-α agonist resulted in a 50% reduction in rates of fatty acid oxidation, with a concomitant increase in glycolysis (1.7-fold) and glucose oxidation (2.3- fold). Correction of the diabetes-induced abnormalities in systemic and cardiac metabolism after BM 17.0744 treatment did not, however, improve left ventricular contractile function.


2005 ◽  
Vol 288 (1) ◽  
pp. H77-H82 ◽  
Author(s):  
Shintaro Nemoto ◽  
Peter Razeghi ◽  
Masakuni Ishiyama ◽  
Gilberto De Freitas ◽  
Heinrich Taegtmeyer ◽  
...  

Previously we reported that the beneficial effects of β-adrenergic blockade in chronic mitral regurgitation (MR) were in part due to induction of bradycardia, which obviously affects myocardial energy requirements. From this observation we hypothesized that part of the pathophysiology of MR may involve faulty energy substrate utilization, which in turn might lead to potentially harmful lipid accumulation as observed in other models of heart failure. To explore this hypothesis, we measured triglyceride accumulation in the myocardia of dogs with chronic MR and then attempted to enhance myocardial metabolism by chronic administration of the peroxisome proliferator-activated receptor (PPAR)-γ agonist rosiglitazone. Cardiac tissues were obtained from three groups of dogs that included control animals, dogs with MR for 3 mo without treatment, and dogs with MR for 6 mo that were treated with rosiglitazone (8 mg/day) for the last 3 mo of observation. Hemodynamics and contractile function (end-systolic stress-strain relationship, as measured by K index) were assessed at baseline, 3 mo of MR, and 6 mo of MR (3 mo of the treatment). Lipid accumulation in MR (as indicated by oil red O staining score and TLC analysis) was marked and showed an inverse correlation with the left ventricular (LV) contractility. LV contractility was significantly restored after PPAR therapy (K index: therapy, 3.01 ± 0.11*; 3 mo MR, 2.12 ± 0.34; baseline, 4.01 ± 0.29; ANOVA, P = 0.038; * P < 0.05 vs. 3 mo of MR). At the same time, therapy resulted in a marked reduction of intramyocyte lipid. We conclude that 1) chronic MR leads to intramyocyte myocardial lipid accumulation and contractile dysfunction, and 2) administration of the PPAR-γ agonist rosiglitazone ameliorates MR-induced LV dysfunction accompanied by a decline in lipid content.


2017 ◽  
Vol 312 (2) ◽  
pp. H239-H249 ◽  
Author(s):  
Stephen W. Standage ◽  
Brock G. Bennion ◽  
Taft O. Knowles ◽  
Dolena R. Ledee ◽  
Michael A. Portman ◽  
...  

Children with sepsis and multisystem organ failure have downregulated leukocyte gene expression of peroxisome proliferator-activated receptor-α (PPARα), a nuclear hormone receptor transcription factor that regulates inflammation and lipid metabolism. Mouse models of sepsis have likewise demonstrated that the absence of PPARα is associated with decreased survival and organ injury, specifically of the heart. Using a clinically relevant mouse model of early sepsis, we found that heart function increases in wild-type (WT) mice over the first 24 h of sepsis, but that mice lacking PPARα ( Ppara−/−) cannot sustain the elevated heart function necessary to compensate for sepsis pathophysiology. Left ventricular shortening fraction, measured 24 h after initiation of sepsis by echocardiography, was higher in WT mice than in Ppara−/− mice. Ex vivo working heart studies demonstrated greater developed pressure, contractility, and aortic outflow in WT compared with Ppara−/− mice. Furthermore, cardiac fatty acid oxidation was increased in WT but not in Ppara−/− mice. Regulatory pathways controlling pyruvate incorporation into the citric acid cycle were inhibited by sepsis in both genotypes, but the regulatory state of enzymes controlling fatty acid oxidation appeared to be permissive in WT mice only. Mitochondrial ultrastructure was not altered in either genotype indicating that severe mitochondrial dysfunction is unlikely at this stage of sepsis. These data suggest that PPARα expression supports the hyperdynamic cardiac response early in the course of sepsis and that increased fatty acid oxidation may prevent morbidity and mortality. NEW & NOTEWORTHY In contrast to previous studies in septic shock using experimental mouse models, we are the first to demonstrate that heart function increases early in sepsis with an associated augmentation of cardiac fatty acid oxidation. Absence of peroxisome proliferator-activated receptor-α (PPARα) results in reduced cardiac performance and fatty acid oxidation in sepsis.


2013 ◽  
Vol 304 (12) ◽  
pp. E1348-E1358 ◽  
Author(s):  
Pawel Dobrzyn ◽  
Aleksandra Pyrkowska ◽  
Monika K. Duda ◽  
Tomasz Bednarski ◽  
Michal Maczewski ◽  
...  

Cardiac hypertrophy is accompanied by molecular remodeling that affects different cellular pathways, including fatty acid (FA) utilization. In the present study, we show that cardiac lipid metabolism is differentially regulated in response to physiological (endurance training) and pathological [abdominal aortic banding (AAB)] hypertrophic stimuli. Physiological hypertrophy was accompanied by an increased expression of lipogenic genes and the activation of sterol regulatory element-binding protein-1c and Akt signaling. Additionally, FA oxidation pathways regulated by AMP-activated protein kinase (AMPK) and peroxisome proliferator activated receptor-α (PPARα) were induced in trained hearts. Cardiac lipid content was not changed by physiological stimulation, underlining balanced lipid utilization in the trained heart. Moreover, pathological hypertrophy induced the AMPK-regulated oxidative pathway, whereas PPARα and expression of its downstream targets, i.e., acyl-CoA oxidase and carnitine palmitoyltransferase I, were not affected by AAB. In contrast, pathological hypertrophy leads to cardiac triglyceride (TG) and diacylglycerol (DAG) accumulation, although the expression of lipogenic genes and the levels of FA transport proteins (CD36 and FATP) were not changed or reduced compared with the sham group. A possible explanation for this phenomenon is a decrease in lipolysis, as evidenced by the increased content of adipose triglyceride lipase inhibitor G0S2, the increased phosphorylation of hormone-sensitive lipase at Ser565, and the decreased protein levels of DAG lipase that attenuate TG and DAG contents. The increased TG and DAG accumulation observed in AAB-induced hypertrophy might have lipotoxic effects, thereby predisposing to cardiomyopathy and heart failure in the future.


2016 ◽  
Vol 45 (2) ◽  
pp. 344-352 ◽  
Author(s):  
Michael E. Dunn ◽  
Thomas G. Manfredi ◽  
Kevin Agostinucci ◽  
Steven K. Engle ◽  
Josh Powe ◽  
...  

Given the proven utility of natriuretic peptides as serum biomarkers of cardiovascular maladaptation and dysfunction in humans and the high cross-species sequence conservation of atrial natriuretic peptides, natriuretic peptides have the potential to serve as translational biomarkers for the identification of cardiotoxic compounds during multiple phases of drug development. This work evaluated and compared the response of N-terminal proatrial natriuretic peptide (NT-proANP) and N-terminal probrain natriuretic peptide (NT-proBNP) in rats during exercise-induced and drug-induced increases in cardiac mass after chronic swimming or daily oral dosing with a peroxisome proliferator-activated receptor γ agonist. Male Sprague-Dawley rats aged 8 to 10 weeks were assigned to control, active control, swimming, or drug-induced cardiac hypertrophy groups. While the relative heart weights from both the swimming and drug-induced cardiac hypertrophy groups were increased 15% after 28 days of dosing, the serum NT-proANP and NT-proBNP values were only increased in association with cardiac hypertrophy caused by compound administration. Serum natriuretic peptide concentrations did not change in response to adaptive physiologic cardiac hypertrophy induced by a 28-day swimming protocol. These data support the use of natriuretic peptides as fluid biomarkers for the distinction between physiological and drug-induced cardiac hypertrophy.


2003 ◽  
Vol 95 (4) ◽  
pp. 1638-1647 ◽  
Author(s):  
J. David Symons ◽  
Yoko Hayashi ◽  
Jodi L. Ensunsa

We hypothesized that myocardial contractile function and coronary arterial function are greater after ischemia and reperfusion in high-intensity treadmill-trained vs. sedentary rats. Rats performed 10 × 4-min bouts of treadmill running consisting of 2 min at 13 m/min + 2 min at 45-60 m/min (Etr) or were sedentary (Sed) for 12 wk. Animals then were instrumented to measure left ventricular (LV) contractility in response to three 15-min coronary occlusion (O) and 5-min reperfusion (R) cycles (Isc) or a sham operation (Sham). After the Isc and Sham protocols, hearts were excised and coronary arterial (∼105 μm ID) function was evaluated by using isometric techniques. LV developed pressure, the first derivative of LV pressure at a developed pressure of 40 mmHg, and systolic blood pressure were not different between Etr ( n = 14) and Sed ( n = 7) rats before or after the Sham protocol. Furthermore, hemodynamic variables were similar in Etr ( n = 14) and Sed ( n = 13) animals before the Isc protocol and were depressed to the same degree by the three O-R cycles. Therefore, Etr did not alter myocardial contractile function in rats that were (i.e., Isc) or were not (i.e., Sham) exposed to ischemia and reperfusion. Acetylcholine-evoked relaxation (10-8 to 3 × 10-5 M) was greater ( P < 0.05) in coronary arteries from Sham-Etr vs. Sham-Sed animals (5 of 8 doses tested) and Isc-Etr vs. Isc-Sed rats (3 of 8 doses tested). Maximal relaxation produced by sodium nitroprusside (10-4 M) was similar among groups. Vasocontractile responses produced by KCl (10-100 mM) and endothelin-1 (10-11-10-4 M) were greater ( P < 0.05) in the presence vs. the absence of nitric oxide synthase inhibition (10-6 M NG-monomethyl-l-arginine) in vessels from Sham-Etr but not Sham-Sed rats and from Isc-Etr but not Isc-Sed rats. These findings suggest that Etr-evoked improvements in coronary function are maintained in small arteries even when exposed to ischemia and reperfusion.


2017 ◽  
Vol 126 (01) ◽  
pp. 27-38 ◽  
Author(s):  
Mohamed Wassef ◽  
Ola Tork ◽  
Laila Rashed ◽  
Walaa Ibrahim ◽  
Heba Morsi ◽  
...  

AbstractTherapy targeting mitochondria may provide novel ways to treat diabetes and its complications. Bone marrow-derived mesenchymal stem cells (MSCs), the peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists and exendin-4; an analog of glucagon-like peptide-1 have shown cardioprotective properties in many cardiac injury models. So, we evaluated their effects in diabetic cardiomyopathy (DCM) in relation to mitochondrial dysfunction. This work included seven groups of adult male albino rats: the control group, the non-treated diabetic group, and the treated diabetic groups: one group was treated with MSCs only, the second with pioglitazone only, the third with MSCs and pioglitazone, the forth with exendin-4 only and the fifth with MSCs and exendin-4. All treatments were started after 6 weeks from induction of diabetes and continued for the next 4 weeks. Blood samples were collected for assessment of glucose, insulin, and cardiac enzymes. Hearts were removed and used for isolated heart studies, and gene expression of: myocyte enhancer factor-2 (Mef2), peroxisome proliferator-activated receptor gamma coactivator1-alpha (PGC1α), nuclear factor kappa B (NFKB) and autophagic markers: light chain 3 (LC3) and beclin by real-time reverse transcription-polymerase chain reaction. The cardiac mitochondrial protein levels of cardiolipin and uncoupler protein 2 (UCP2) were assessed by ELISA and western blot technique, respectively. Treated groups showed significant improvement in left ventricular function associated with improvement in the cardiac injury and myopathic markers compared to the non treated diabetic group. NFKB was down-regulated while cardiolipin, PGC1α, LC.3 and beclin were up-regulated in all treated groups. These data suggest that the cardioprotective effects of MSCs, exendin-4 or pioglitazone based on their ability to improve mitochondrial functions through targeting inflammatory and autophagy signaling. The co- administration of pioglitazone or exendin-4 with MSCs showed significant superior improvement compared with MSCs alone, indicating the ability to use them in supporting cardioprotective effects of MSCs.


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