scholarly journals Reducing Caloric Intake Prevents Ischemic Injury and Myocardial Dysfunction and Affects Anesthetic Cardioprotection in Type 2 Diabetic Rats

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Charissa E. van den Brom ◽  
Christa Boer ◽  
Rob F. P. van den Akker ◽  
Stephan A. Loer ◽  
R. Arthur Bouwman

Background. Type 2 diabetes mellitus (T2DM) increases the risk of myocardial ischemia, followed by increased perioperative risk of cardiovascular morbidity. We investigated whether reducing caloric intake reduces ischemic injury and myocardial dysfunction and affects the protective effects of the volatile anesthetic sevoflurane in diet-induced T2DM rats.Methods. Rats received a western (WD) or control diet (CD). Caloric intake was reduced by reversing WD-fed rats to CD. Myocardial function was determined with echocardiography. After 8 weeks of diet feeding, myocardial infarction was induced and the effect of sevoflurane was studied on myocardial function and ischemia/reperfusion injury.Results. WD-feeding resulted in a mild T2DM phenotype and myocardial dysfunction. Sevoflurane further impaired systolic function in WD-fed rats. Unexpectedly, WD-feeding reduced infarct size compared to CD-feeding. Sevoflurane reduced infarct size in CD-fed rats; however it enlarged infarct size in WD-fed rats. Caloric reduction restored myocardial dysfunction and the protective effect of sevoflurane against ischemia compared to WD-fed rats, whereas the protective effects of WD-feeding persisted.Conclusion. Caloric reduction restored the T2DM phenotype and myocardial function, while the cardioprotective properties of WD-feeding or sevoflurane persisted. Our data suggest that reducing caloric intake in T2DM might be a possible intervention to reduce perioperative risk of cardiovascular morbidity.

2017 ◽  
Vol 122 (6) ◽  
pp. 1452-1461 ◽  
Author(s):  
Petra Alánová ◽  
Anna Chytilová ◽  
Jan Neckář ◽  
Jaroslav Hrdlička ◽  
Petra Míčová ◽  
...  

Chronic hypoxia and exercise are natural stimuli that confer sustainable cardioprotection against ischemia-reperfusion (I/R) injury, but it is unknown whether they can act in synergy to enhance ischemic resistance. Inflammatory response mediated by tumor necrosis factor-α (TNF-α) plays a role in the infarct size limitation by continuous normobaric hypoxia (CNH), whereas exercise is associated with anti-inflammatory effects. This study was conducted to determine if exercise training performed under conditions of CNH (12% O2) affects myocardial ischemic resistance with respect to inflammatory and redox status. Adult male Wistar rats were assigned to one of the following groups: normoxic sedentary, normoxic trained, hypoxic sedentary, and hypoxic trained. ELISA and Western blot analysis, respectively, were used to quantify myocardial cytokines and the expression of TNF-α receptors, nuclear factor-κB (NF-κB), and selected components of related signaling pathways. Infarct size and arrhythmias were assessed in open-chest rats subjected to I/R. CNH increased TNF-α and interleukin-6 levels and the expression of TNF-α type 2 receptor, NF-κB, inducible nitric oxide synthase (iNOS), cytosolic phospholipase A2α, cyclooxygenase-2, manganese superoxide dismutase (MnSOD), and catalase. None of these effects occurred in the normoxic trained group, whereas exercise in hypoxia abolished or significantly attenuated CNH-induced responses, except for NF-κB, iNOS, and MnSOD. Both CNH and exercise reduced infarct size, but their combination provided the same degree of protection as CNH alone. In conclusion, exercise training does not amplify the cardioprotection conferred by CNH. High ischemic tolerance of the CNH hearts persists after exercise, possibly by maintaining the increased antioxidant capacity despite attenuating TNF-α-dependent protective signaling. NEW & NOTEWORTHY Chronic hypoxia and regular exercise are natural stimuli that confer sustainable myocardial protection against acute ischemia-reperfusion injury. Signaling mediated by TNF-α via its type 2 receptor plays a role in the cardioprotective mechanism of chronic hypoxia. In the present study, we found that exercise training of rats during adaptation to hypoxia does not amplify the infarct size-limiting effect. Ischemia-resistant phenotype is maintained in the combined hypoxia-exercise setting despite exercise-induced attenuation of TNF-α-dependent protective signaling.


2013 ◽  
Vol 305 (4) ◽  
pp. H542-H550 ◽  
Author(s):  
Toshihiro Shinbo ◽  
Kenichi Kokubo ◽  
Yuri Sato ◽  
Shintaro Hagiri ◽  
Ryuji Hataishi ◽  
...  

Inhaled nitric oxide (NO) has been reported to decrease the infarct size in cardiac ischemia-reperfusion (I/R) injury. However, reactive nitrogen species (RNS) produced by NO cause myocardial dysfunction and injury. Because H2 is reported to eliminate peroxynitrite, it was expected to reduce the adverse effects of NO. In mice, left anterior descending coronary artery ligation for 60 min followed by reperfusion was performed with inhaled NO [80 parts per million (ppm)], H2 (2%), or NO + H2, starting 5 min before reperfusion for 35 min. After 24 h, left ventricular function, infarct size, and area at risk (AAR) were assessed. Oxidative stress associated with reactive oxygen species (ROS) was evaluated by staining for 8-hydroxy-2′-deoxyguanosine and 4-hydroxy-2-nonenal, that associated with RNS by staining for nitrotyrosine, and neutrophil infiltration by staining for granulocyte receptor-1. The infarct size/AAR decreased with breathing NO or H2 alone. NO inhalation plus H2 reduced the infarct size/AAR, with significant interaction between the two, reducing ROS and neutrophil infiltration, and improved the cardiac function to normal levels. Although nitrotyrosine staining was prominent after NO inhalation alone, it was eliminated after breathing a mixture of H2 with NO. Preconditioning with NO significantly reduced the infarct size/AAR, but not preconditioning with H2. In conclusion, breathing NO + H2 during I/R reduced the infarct size and maintained cardiac function, and reduced the generation of myocardial nitrotyrosine associated with NO inhalation. Administration of NO + H2 gases for inhalation may be useful for planned coronary interventions or for the treatment of I/R injury.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Juan Valle Raleigh ◽  
Adolfo G Mauro ◽  
Carlo Marchetti ◽  
Jun He ◽  
Stefano Toldo ◽  
...  

Background: The preconditioning-like infarct-sparing and anti-inflammatory effects of the peptide hormone relaxin following ischemic injury have been studied in the heart. Whether reperfusion therapy with recombinant human relaxin (serelaxin, SRLX) reduces myocardial infarct size and attenuates NLRP3 inflammasome formation/caspase-1 activation and subsequent loss of functional myocardium following ischemia/reperfusion (I/R) injury is unknown. Methods and Results: After baseline echocardiography, adult male C57BL (WT) or eNOS knockout (KO) mice underwent myocardial infarction (MI) by coronary artery ligation for 30 minutes followed by 24 h reperfusion. Mice were treated with either SRLX (10 μg/Kg; sc) or saline 5 minutes before reperfusion. SRLX improved survival at 24 h post MI in WT mice (79%) as compared with controls (42%), whereas there was no difference in survival between SRLX- and saline-treated eNOS KO mice. Moreover, SRLX significantly reduced infarct size, measured with TTC staining, and preserved LV fractional shortening (FS) and end-systolic diameter (LVESD) in WT mice as compared with controls. Interestingly, cardiac caspase-1 activity was markedly reduced in SRLX-treated mice compared with controls at 24 h post MI (Figure A-D). Genetic deletion of eNOS abolished the infarct-sparing and anti-inflammatory effects of SRLX as well as functional preservation. SRLX plasma levels were assessed 5 min. after treatment using ELISA and the results demonstrate therapeutic levels comparable to plasma relaxin during the first trimester of pregnancy (Figure E). Conclusion: Reperfusion therapy with SRLX attenuates myocardial I/R injury and NLRP3 inflammasome formation via eNOS-dependent mechanism. We propose that SRLX possesses an anti-inflammatory effect preventing caspase-1 activation and inflammatory complications following MI, which may shed some light on the mechanism behind the survival benefit observed in the RELAX-AHF trial.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Zhengfei Yang ◽  
Jiangang Wang ◽  
Lu Yin ◽  
Shen Zhao ◽  
Ziren Tang ◽  
...  

Introduction: Curcumin has been proven to provide potent protection of vital organs against regional ischemia reperfusion injury. In this study, we investigated the effects of curcumin on the outcomes of CPR in a rat model of cardiac arrest. Hypothesis: Curcumin reduces the severity of post-CPR myocardial dysfunction and prolong the duration of survival. Method: Sixteen male Sprague-Dawley rats weighing between 450-550g were randomized into two groups: 1) Placebo; 2) Curcumin (100 mg/kg) pre-treatment. Ventricular fibrillation (VF) was induced. After 8 mins of VF, CPR was initiated for 8 mins and defibrillation was then attempted. Myocardial function was measured by echocardiography at baseline and hourly for 4 hours following successful resuscitation. The duration of survival was observed for total 72 hours. Result: Six animals in the placebo group and seven in the curcumin group were successfully resuscitated. Post-resuscitation myocardial function was significantly impaired in all animals. However, myocardial function gradually improved 4 hours after resuscitation and was significantly better in the animals pre-treated with curcumin (Figure). Significantly shorter duration of survival of 40±29 hours was observed in the placebo group. Conclusion: In a rat model of cardiac arrest, curcuminim proves post-resuscitation myocardial dysfunction and prolongs the duration of survival.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Juhyun Song ◽  
Joohyun Park ◽  
Yumi Oh ◽  
Jong Eun Lee

Ischemic stroke interrupts the flow of blood to the brain and subsequently results in cerebral infarction and neuronal cell death, leading to severe pathophysiology. Glutathione (GSH) is an antioxidant with cellular protective functions, including reactive oxygen species (ROS) scavenging in the brain. In addition, GSH is involved in various cellular survival pathways in response to oxidative stress. In the present study, we examined whether GSH reduces cerebral infarct size after middle cerebral artery occlusionin vivoand the signaling mechanisms involved in the promotion of cell survival after GSH treatment under ischemia/reperfusion conditionsin vitro. To determine whether GSH reduces the extent of cerebral infarction, cell death after ischemia, and reperfusion injury, we measured infarct size in ischemic brain tissue and the expression of claudin-5 associated with brain infarct formation. We also examined activation of the PI3K/Akt pathway, inactivation of FOXO3, and expression of Bcl2 to assess the role of GSH in promoting cell survival in response to ischemic injury. Based on our results, we suggest that GSH might improve the pathogenesis of ischemic stroke by attenuating cerebral infarction and cell death.


2004 ◽  
Vol 287 (4) ◽  
pp. H1786-H1791 ◽  
Author(s):  
Shinji Okubo ◽  
Yujirou Tanabe ◽  
Kenji Takeda ◽  
Michihiko Kitayama ◽  
Seiyu Kanemitsu ◽  
...  

We examined whether ischemic preconditioning (IPC) attenuates ischemia-reperfusion injury, in part, by decreasing apoptosis and whether the δ-opioid receptor (DOR) plays a pivotal role in the regulation of apoptosis. Rabbits were subjected to 30-min coronary artery occlusion (CAO) and 180 min of reperfusion. IPC was elicited with four cycles of 5-min ischemia and 10-min reperfusion before CAO. Morphine (0.3 mg/kg iv) was given 15 min before CAO. Naloxone (Nal; 10 mg/kg iv) and naltrindole (Nti; 10 mg/kg iv), the respective nonselective and selective DOR antagonists were given 10 min before either morphine or IPC. Infarct size (%risk area) was reduced from 46 ± 3.8 in control to 11.6 ± 1.0 in IPC and 19.5 ± 3.8 in the morphine group (means ± SE; P < 0.001 vs. control). Nal blocked the protective effects of IPC and morphine, as shown by the increase in infarct size to 38.6 ± 7.2 and 44.5 ± 1.8, respectively. Similarly, Nti blocked IPC and morphine-induced protection. The percentage of apoptotic cells (revealed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay) decreased in IPC (3.6 ± 1.9) and morphine groups (5.2 ± 1.2) compared with control group (12.4 ± 1.6; P < 0.001). Nti pretreatment increased apoptotic cells 11.2 ± 2.2% in IPC and 12.1 ± 0.8% in morphine groups. Nal failed to block inhibition of apoptosis in the IPC group (% of cells: 5.7 ± 1.3 vs. 3.6 ± 1.9 in IPC alone; P > 0.05). These results were also confirmed by nucleosomal DNA laddering pattern. We conclude that IPC reduces lethal injury, in part, by decreasing apoptosis after ischemia-reperfusion and activation of the DOR may play a crucial role in IPC or morphine-induced myocardial protection.


2018 ◽  
Vol 125 (2) ◽  
pp. 340-352 ◽  
Author(s):  
Alejandro Ciocci Pardo ◽  
Romina G. Díaz ◽  
Luisa F. González Arbeláez ◽  
Néstor G. Pérez ◽  
Erik R. Swenson ◽  
...  

During ischemia, increased anaerobic glycolysis results in intracellular acidosis. Activation of alkalinizing transport mechanisms associated with carbonic anhydrases (CAs) leads to myocardial intracellular Ca2+ increase. We characterize the effects of inhibition of CA with benzolamide (BZ) during cardiac ischemia-reperfusion (I/R). Langendorff-perfused isolated rat hearts were subjected to 30 min of global ischemia and 60 min of reperfusion. Other hearts were treated with BZ (5 μM) during the initial 10 min of reperfusion or perfused with acid solution (AR, pH 6.4) during the first 3 min of reperfusion. p38MAPK, a kinase linked to membrane transporters and involved in cardioprotection, was examined in hearts treated with BZ in presence of the p38MAPK inhibitor SB202190 (10 μM). Infarct size (IZ) and myocardial function were assessed, and phosphorylated forms of p38MAPK, Akt, and PKCε were evaluated by immunoblotting. We determined the rate of intracellular pH (pHi) normalization after transient acid loading in the absence and presence of BZ or BZ + SB202190 in heart papillary muscles (HPMs). Mitochondrial membrane potential (ΔΨm), Ca2+ retention capacity and Ca2+-mediated swelling after I/R were also measured. BZ, similarly to AR, reduced IZ, improved postischemic recovery of myocardial contractility, increased phosphorylation of Akt, PKCε, and p38MAPK, and normalized ΔΨm and Ca2+ homeostasis, effects abolished after p38MAPK inhibition. In HPMs, BZ slowed pHi recovery, an effect that was restored after p38MAPK inhibition. We conclude that prolongation of acidic conditions during reperfusion by BZ could be responsible for the cardioprotective benefits of reduced infarction and better myocontractile function, through p38MAPK-dependent pathways. NEW & NOTEWORTHY Carbonic anhydrase inhibition by benzolamide (BZ) maintains acidity, decreases infarct size, and improves postischemic myocardial dysfunction in ischemia-reperfusion (I/R) hearts. Protection afforded by BZ mimicked the beneficial effects elicited by an acidic solution (AR). Increased phosphorylation of p38MAPK occurs in I/R hearts reperfused with BZ or with AR. Mitochondria from I/R hearts possess abnormal Ca2+ handling and a more depolarized membrane potential compared with control hearts, and these changes were restored by treatment with BZ or AR.


2018 ◽  
Vol 236 (2) ◽  
pp. 69-84 ◽  
Author(s):  
Pongpan Tanajak ◽  
Piangkwan Sa-nguanmoo ◽  
Sivaporn Sivasinprasasn ◽  
Savitree Thummasorn ◽  
Natthaphat Siri-Angkul ◽  
...  

Sodium-glucose cotransporter 2 inhibitor (SGLT2-i) effects on cardiac ischemia/reperfusion (I/R) injury are unclear. Unlike SGLT2-i, dipeptidyl peptidase 4 inhibitors (DPP4-i) have shown effective cardioprotection in cardiac I/R injury. We aimed to investigate whether SGLT2-i reduces myocardial dysfunction and myocardial injury to a greater extent than DPP4-i in obese insulin-resistant rats with/without cardiac I/R injury. The high-fat (HF) diet-induced obese insulin-resistant rats were divided into 4 groups and received the following treatments for 28 days: vehicle (HFV); vildagliptin at a dosage of 3 mg/kg/day (HFVil); dapagliflozin at a dosage of 1 mg/kg/day (HFDa) and combination drugs (HFDaVil). At the end, I/R injury was induced by a 30-min left anterior descending coronary occlusion and 120-min reperfusion. Dapagliflozin showed a greater efficacy than vildagliptin in improving the metabolic impairments, low frequency/high frequency (LF/HF) ratio, systolic blood pressure and left ventricular (LV) function in comparison to HFV rats. In cardiac I/R injury, dapagliflozin had a greater efficacy than vildagiptin in decreasing mitochondrial DRP1, cleaved caspase 3, LV dysfunction and infarct size in comparison to HFV rats. However, the combined therapy showed the greatest efficacy in attenuating LV dysfunction, mitochondrial DRP1 and infarct size in comparison to HFV rats. In conclusion, dapagliflozin has a more pronounced effect than vildagliptin in obese insulin-resistant rats for the improvement of LV function. In rats with cardiac I/R injury, although dapagliflozin had a greater efficacy on cardioprotection than vildagliptin, the combined therapy exerted the highest cardioprotective effects potentially by reducing mitochondrial fission.


2007 ◽  
Vol 293 (5) ◽  
pp. H2845-H2852 ◽  
Author(s):  
Rong Jiang ◽  
Amanda Zatta ◽  
Hajime Kin ◽  
Ningping Wang ◽  
James G. Reeves ◽  
...  

Protease-activated receptor-2 (PAR-2) may have proinflammatory effects in some tissues and protective effects in other tissues. The role of PAR-2 in in vivo myocardial ischemia-reperfusion has not yet been determined. This study tested the hypothesis that PAR-2 activation with the PAR-2 agonist peptide SLIGRL (PAR-2 AP) reduces myocardial infarct size when given at reperfusion in vivo, and this cardioprotection involves the ERK1/2 pathway. Anesthetized rats were randomly assigned to the following groups with 30 min of regional ischemia and 3 h reperfusion: 1) control with saline; 2) vehicle (DMSO); 3) PAR-2 AP, 1 mg/kg given intravenously 5 min before reperfusion; 4) scrambled peptide (SP), 1 mg/kg; 5) the ERK1/2 inhibitor PD-98059 (PD), 0.3 mg/kg given 10 min before reperfusion; 6) the phosphatidylinositol 3-kinase inhibitor LY-294002 (LY), 0.3 mg/kg given 10 min before reperfusion; 7) PD + PAR-2 AP, 0.3 mg/kg PD given 5 min before PAR-2 AP; 8) LY + PAR-2 AP, 0.3 mg/kg LY given 5 min before PAR-2 AP; 9) chelerythrine (Chel) alone, 5 mg/kg given 10 min before reperfusion; and 10) Chel + PAR-2 AP, Chel was given 5 min before PAR-2 AP (10 min before reperfusion). Activation of ERK1/2, ERK5, Akt, and the downstream targets of ERK1/2 [P90 RSK and bcl-xl/bcl-2-associated death promoter (BAD)] was determined by Western blot analysis in separate experiments. PAR-2 AP significantly reduced infarct size compared with control (36 ± 2% vs. 53 ± 1%, P < 0.05), and SP had no effect on infarct size (53 ± 3%). PAR-2 AP significantly increased phosphorylation of ERK1/2, p90RSK, and BAD but not Akt or ERK5. Accordingly, the infarct-size sparing effect of PAR-2 AP was abolished by PD (PAR-2 AP, 36 ± 2% vs. PD + PAR-2 AP, 50 ± 1%; P < 0.05) and by Chel (Chel + PAR-2 AP, 58 ± 2%) but not by LY (PAR-2 AP, 36 ± 2% vs. LY + PAR-2 AP, 38 ± 3%; P > 0.05). Therefore, PAR-2 activation is cardioprotective in the in vivo rat heart ischemia-reperfusion model, and this protection involves the ERK1/2 pathway and PKC.


2014 ◽  
Vol 934 ◽  
pp. 165-172
Author(s):  
Cai Hong Bai ◽  
Hai Bo He ◽  
Fan Cheng ◽  
Jun Zhi Wang ◽  
Xiao Chen ◽  
...  

Saponins from Rhizoma Panacis Majoris (SRPM), the bioactive component inRhizoma Panacis Majoris, were reported to possess protective effects on myocardial injury, but the underlying mechanisms remain poorly understood. This study was performed to investigate the protective effects and possible mechanism of SRPM on myocardial ischemia/reperfusion (I/R) injury in vivo. Cardioprotective effects of SPRM in I/R rats was evaluated by hemodynamic, infarct size, biochemical values, histopathological observations, antioxidative relative gene expressions; And the antioxidant activity of SPRM was studied using DPPH scavenging and β-carotene/linoleic acid tests. In the study, we found that SRPM possessed significant free radical-scavenging activity and considerable antioxidant activity, and significantly improved cardiac function, serum biochemical index and antioxidation level, decreased infarct size, reversed the down-regulated mRNA expressions of the SOD1, SOD2, SOD3 in I/R rats. The studies demonstrated that oxidative stress caused the overgeneration and accumulation of ROS, which was central of myocardial I/R injury. SPRM exerted beneficially cardioprotective effects on myocardial I/R injury, mainly scavenging oxidative stress-triggered overgeneration and accumulation of ROS, alleviating myocardial I/R injury and apoptotic cell death.


Sign in / Sign up

Export Citation Format

Share Document