scholarly journals Simulated urban carbon monoxide air pollution exacerbates rat heart ischemia-reperfusion injury

2010 ◽  
Vol 298 (5) ◽  
pp. H1445-H1453 ◽  
Author(s):  
G. Meyer ◽  
L. André ◽  
S. Tanguy ◽  
J. Boissiere ◽  
C. Farah ◽  
...  

Myocardial damages due to ischemia-reperfusion (I/R) are recognized to be the result of a complex interplay between genetic and environmental factors. Epidemiological studies suggested that, among environmental factors, carbon monoxide (CO) urban pollution can be linked to cardiac diseases and mortality. The aim of this work was to evaluate the impact of exposure to CO pollution on cardiac sensitivity to I/R. Regional myocardial I/R was performed on isolated perfused hearts from rats exposed for 4 wk to air enriched with CO (30–100 ppm). Functional variables, reperfusion ventricular arrhythmias (VA) and cellular damages (infarct size, lactate dehydrogenase release) were assessed. Sarcomere length shortening and Ca2+ handling were evaluated in intact isolated cardiomyocytes during a cellular anoxia-reoxygenation protocol. The major results show that prolonged CO exposure worsens myocardial I/R injuries, resulting in increased severity of postischemic VA, impaired recovery of myocardial function, and increased infarct size (60 ± 5 vs. 33 ± 2% of ischemic zone). The aggravating effects of CO exposure on I/R could be explained by a reduced myocardial enzymatic antioxidant status (superoxide dismutase −45%; glutathione peroxidase −49%) associated with impaired intracellular Ca2+ handling. In conclusion, our results are consistent with the idea that chronic CO pollution dramatically increases the severity of myocardial I/R injuries.

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Jingyuan li ◽  
Zoltan Pierre Arany ◽  
Mansoureh Eghbali

Angiogenesis plays an important role in the pathogenesis of cardiovascular disease. Pro-angiogenic and anti-angiogenic treatments have provided new insights into the impact of angiogenesis-based approaches on coronary artery disease. We have recently reported that the hearts of late pregnant (LP) mice are more prone to ischemia/reperfusion (I/R) injury compared to non pregnant(NP) mice. Provided the significant change of angiogenesis status in pregnancy, here we explored whether stimulating the angiogenesis with VEGF is able to protect the heart against I/R injury in late pregnancy, and whether anti-antigenic treatment with soluble endoglin(sENG), an anti-angiogenic factor, aggravates cardiac I/R injury in NP. Pregnant mice at day 12 either received daily injection of VEGF (100 ug/kg daily subcutaneous injection) or PBS(LP CTRL) for 7 days, and at day 19 the LP mice hearts were subjected to 20 min ischemia followed by 40 min reperfusion in Langendorff. NP mice either received a single adenovirus sENG(2х10 8particles via tail vein injection) or vehicle(NP CTRL), and 10 days later NP mice were subjected to 20 min ischemia followed by 40 min reperfusion in Langendorff. The heart function was recorded throughout the experiments, and the infarct size was measured by TTC staining at the end of experiments. Exogenous VEGF treatment significantly improved the cardiac function of LP mice after ischemia. The rate pressure product (RPP) at the end of reperfusion was improved from 1617±287 mmHg*beats/min (n=6) in LP CTRL to 11287±1783 mmHg*beats/min (n=3) in the VEGF group(p<0.01). The infarct size was also significantly reduced by VEGF treatment to 25.0±4.3% (n=3) from 57.4±5.2%(n=6) in CTRL (p<0.01). While sENG aggravated the cardiac I/R injury in NP, as the RPP at the end of reperfusion in the sENG group (4523±1281 mmHg*beats/min, n=4) was significantly lower compared with NP CTRL group(12818±1213 mmHg*beats/min, n=6)(p<0.01). Furthermore, the infarct size in the sENG group was markedly higher compared with NP CTRL group (34.0±3.3% (n=4) vs. 16.3±1.4%(n=6) in NP CTRL, p<0.05). In conclusion, anti-angiogenic treatment aggravates the cardiac I/R injury in NP, while angiogenic therapy protects the heart against I/R injury in LP.


2001 ◽  
Vol 281 (6) ◽  
pp. H2398-H2409 ◽  
Author(s):  
Jianzhong An ◽  
Srinivasan G. Varadarajan ◽  
Amadou Camara ◽  
Qun Chen ◽  
Enis Novalija ◽  
...  

We determined in intact hearts whether inhibition of Na+/H+ exchange (NHE) decreases intracellular Na+ and Ca2+ during ischemia and reperfusion, improves function during reperfusion, and reduces infarct size. Guinea pig isolated hearts were perfused with Krebs-Ringer solution at 37°C. Left ventricular (LV) free wall intracellular Na+ concentration ([Na+]i) and intracellular Ca2+ concentration ([Ca2+]i) were measured using fluorescence dyes. Hearts were exposed to 30 min of ischemia with or without 10 μM of benzamide (BIIB-513), a selective NHE-1 inhibitor, infused for 10 min just before ischemia or for 10 min immediately on reperfusion. At 2 min of reperfusion, BIIB-513 given before ischemia decreased peak increases in [Na+]i and [Ca2+]i, respectively, from 2.5 and 2.3 times (controls) to 1.6 and 1.3 times preischemia values. At 30 min of reperfusion, BIIB-513 increased systolic-diastolic LV pressure (LVP) from 49 ± 2% (controls) to 80 ± 2% of preischemia values. BIIB-513 reduced ventricular fibrillation by 54% and reduced infarct size from 64 ± 1% to 20 ± 3%. First derivative of the LVP, O2 consumption, and cardiac efficiency were also improved by BIIB-513. Similar results were obtained with BIIB-513 given on reperfusion. These data show that Na+ loading is a marker of reperfusion injury in intact hearts in that inhibiting NHE reduces Na+ and Ca2+ loading during reperfusion while improving function. These results clearly implicate the ionic basis by which inhibiting NHE protects the guinea pig intact heart from ischemia-reperfusion injury.


Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Weiguo Li ◽  
Zhi Qu ◽  
Handong Ma ◽  
Roshini Prakash ◽  
Md Nasrul Hoda ◽  
...  

Diabetes worsens functional outcome after ischemic stroke and is associated with greater hemorrhagic transformation (HT) occurrence. We have shown that male diabetic Goto-Kakizaki (GK) rats develop greater HT and neurological deficit despite smaller infarcts after temporary (3/21 hr) middle cerebral artery occlusion (MCAO) induced by the suture model. The impact of the duration of ischemia/reperfusion (I/R) and the method of ischemia on neurovascular injury and functional outcome in diabetic stroke remain unknown. To address this gap, control Wistar and diabetic GK rats were subjected to 90 min/23 hr, 3 hr/21 hr, or 3 hr/7 day MCAO by suture occlusion or embolus placement. In all groups, infarct size, edema, HT occurrence and severity (hemoglobin level), and functional outcome (grip strength and composite deficit score) were measured (Table). Infarct size was smaller in GK rats with suture or embolic MCAO, but expanded with longer reperfusion period. Edema, HT occurrence and severity were all increased in GK rats after 90 min and 3 hr occlusion with the suture model, but not in the embolic MCAO. Motor deficit was greater in diabetic rats. These findings suggest that diabetes accelerates the development of HT and amplifies vascular damage especially in the suture model where blood flow is rapidly reestablished. These results highlight the importance of earlier vascular protection to improve neurological outcome of acute ischemic stroke in diabetes.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Yasuo M Tsutsumi ◽  
Yoshihiro Ishikawa ◽  
David M Roth ◽  
Hemal H Patel

Introduction: Caveolae are small, flask-like invaginations of the plasma membrane. Caveolins are structural proteins found in caveolae that have scaffolding properties to allow organization of signaling. We have recently shown that both caveolin-1 and caveolin-3 knockout (Cav-1 KO and Cav-3 KO, respectively) mice are unable to be protected from myocardial ischemia-reperfusion injury by acute treatment with volatile anesthetics. Therefore, we tested the hypothesis that delayed cardiac protection induced by volatile anesthetics is caveolin-dependent. Methods: Biochemical assays were performed in excised hearts. Electron microscopy was used to assess caveolae formation. An in vivo mouse model of ischemia-reperfusion injury with delayed anesthetic preconditioning (delayed APC) was tested in wild-type (WT), Cav-1 KO, and Cav-3 KO mice. Mice were exposed to 30 min isoflurane or oxygen and allowed to recover for 24 h. After 24 h recovery, mice underwent 30 min left anterior descending coronary artery occlusion, followed by 2 h of reperfusion at which time infarct size was determined. Results: To elucidate a role for caveolins in delayed APC, wild-type mice were exposed to delayed APC and hearts were fractionated on a discontinuous sucrose gradient to isolate buoyant caveolar membranes. Delayed APC increased the amount of Cav-3 protein but not Cav-1 protein in buoyant fractions. Glucose transporter-4 (GLUT-4), known to interact with Cav-3 and affect cardiac protection, was also increased in buoyant fractions after APC. Microscopically distinct caveolae were observed in WT and Cav-1 KO mice but not Cav-3 KO mice. We assessed the impact of caveolae formation in induction of delayed APC. Infarct size as a percent of the area at risk was reduced by isoflurane in WT (24.0 ± 2.5% vs. 45.1 ± 2.9%, p < 0.05) and Cav-1 KO mice (27.2 ± 4.4%). Cav-3 KO mice did not show delayed APC (41.5 ± 2.2%). Conclusions: These results demonstrate that isoflurane-induced delayed preconditioning involves translocation of Cav-3 and GLUT-4 to caveolae and the presence of microscopically distinct caveolae (dependent on Cav-3 expression) are a requisite for induction of delayed protection in the myocardium. This research has received full or partial funding support from the American Heart Association, AHA Western States Affiliate (California, Nevada & Utah).


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bo Yang ◽  
Li’e Zang ◽  
Jingwen Cui ◽  
Linlin Wei

Abstract Background Stroke serves as a prevalent cerebrovascular disorder with severe cerebral ischemia/reperfusion (CIR) injury, in which neural stem cells (NSCs) play critical roles in the recovery of cerebral function. Circular RNAs (circRNAs) have been widely found to participate in stroke and NSC modulation. However, the role of circRNA TTC3 (circTTC3) in the regulation of CIR injury and NSCs remains elusive. Here, we aimed to explore the impact of circTTC3 on CIR injury and NSCs. Methods The middle cerebral artery occlusion/repression (MCAO/R) model was established in C57BL/6J mice. The primary astrocytes were isolated from the cerebellum from C57BL/6J mice. The primary NSCs were obtained from rat embryos. The effect of circTTC3 on CIR injury and NSCs was analyzed by TTC staining, qPCR, Western blot, LDH colorimetric kits, MTT assays, Annexin V-FITC Apoptosis Detection Kit, luciferase reporter gene assays, and others in the system. Results Significantly, the expression of circTTC3 was elevated in the MCAO/R mice and oxygen and glucose deprivation (OGD)-treated astrocytes. The depletion of circTTC3 attenuated cerebral infarction, neurological score, and brain water content. The OGD treatment induced apoptosis and the levels of lactate dehydrogenase (LDH) in the astrocytes, in which circTTC3 depletion reduced this phenotype in the system. Moreover, the depletion of circTTC3 promoted the proliferation and upregulated the nestin and β-tubulin III expression in NSCs. Mechanically, circTTC3 was able to sponge miR-372-3p, and miR-372-3p can target Toll-like receptor 4 (TLR4) in NSCs. The miR-372-3p inhibitor or TLR4 overexpression could reverse circTTC3 depletion-mediated astrocyte OGD injury and NSC regulation. Conclusion Thus, we conclude that circTTC3 regulates CIR injury and NSCs by the miR-372-3p/TLR4 axis in cerebral infarction. Our finding presents new insight into the mechanism by which circTTC3 modulates CIR injury and NSC dysfunction. CircTTC3, miR-372-3p, and TLR4 may serve as potential targets for the treatment of CIR injury during stroke.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Guixi Mo ◽  
Xin Liu ◽  
Yiyue Zhong ◽  
Jian Mo ◽  
Zhiyi Li ◽  
...  

AbstractIntracellular ion channel inositol 1,4,5-triphosphate receptor (IP3R1) releases Ca2+ from endoplasmic reticulum. The disturbance of IP3R1 is related to several neurodegenerative diseases. This study investigated the mechanism of IP3R1 in myocardial ischemia/reperfusion (MI/R). After MI/R modeling, IP3R1 expression was silenced in myocardium of MI/R rats to explore its role in the concentration of myocardial enzymes, infarct area, Ca2+ level, NLRP3/Caspase-1, and pyroptosis markers and inflammatory factors. The adult rat cardiomyocytes were isolated and cultured to establish hypoxia/reperfusion (H/R) cell model. The expression of IP3R1 was downregulated or ERP44 was overexpressed in H/R-induced cells. Nifedipine D6 was added to H/R-induced cells to block Ca2+ channel or Nigericin was added to activate NLRP3. IP3R1 was highly expressed in myocardium of MI/R rats, and silencing IP3R1 alleviated MI/R injury, reduced Ca2+ overload, inflammation and pyroptosis in MI/R rats, and H/R-induced cells. The binding of ERP44 to IP3R1 inhibited Ca2+ overload, alleviated cardiomyocyte inflammation, and pyroptosis. The increase of intracellular Ca2+ level caused H/R-induced cardiomyocyte pyroptosis through the NLRP3/Caspase-1 pathway. Activation of NLRP3 pathway reversed the protection of IP3R1 inhibition/ERP44 overexpression/Nifedipine D6 on H/R-induced cells. Overall, ERP44 binding to IP3R1 inhibits Ca2+ overload, thus alleviating pyroptosis and MI/R injury.


2006 ◽  
Vol 290 (3) ◽  
pp. C719-C727 ◽  
Author(s):  
Frank C. Chen ◽  
Ozgur Ogut

The severity and duration of ischemia-reperfusion injury is hypothesized to play an important role in the ability of the heart subsequently to recover contractility. Permeabilized trabeculae were prepared from a rat model of ischemia-reperfusion injury to examine the impact on force generation. Compared with the control perfused condition, the maximum force (Fmax) per cross-sectional area and the rate of tension redevelopment of Ca2+-activated trabeculae fell by 71% and 44%, respectively, during ischemia despite the availability of a high concentration of ATP. The reduction in Fmax with ischemia was accompanied by a decline in fiber stiffness, implying a drop in the absolute number of attached cross bridges. However, the declines during ischemia were largely recovered after reperfusion, leading to the hypothesis that intrinsic, reversible posttranslational modifications to proteins of the contractile filaments occur during ischemia-reperfusion injury. Examination of thin-filament proteins from ischemic or ischemia-reperfused hearts did not reveal proteolysis of troponin I or T. However, actin was found to be glutathionylated with ischemia. Light-scattering experiments demonstrated that glutathionylated G-actin did not polymerize as efficiently as native G-actin. Although tropomyosin accelerated the time course of native and glutathionylated G-actin polymerization, the polymerization of glutathionylated G-actin still lagged native G-actin at all concentrations of tropomyosin tested. Furthermore, cosedimentation experiments demonstrated that tropomyosin bound glutathionylated F-actin with significantly reduced cooperativity. Therefore, glutathionylated actin may be a novel contributor to the diverse set of posttranslational modifications that define the function of the contractile filaments during ischemia-reperfusion injury.


2018 ◽  
Vol 115 (10) ◽  
pp. E2302-E2310 ◽  
Author(s):  
Matheus Correa-Costa ◽  
David Gallo ◽  
Eva Csizmadia ◽  
Edward Gomperts ◽  
Judith-Lisa Lieberum ◽  
...  

Ischemia reperfusion injury (IRI) is the predominant tissue insult associated with organ transplantation. Treatment with carbon monoxide (CO) modulates the innate immune response associated with IRI and accelerates tissue recovery. The mechanism has been primarily descriptive and ascribed to the ability of CO to influence inflammation, cell death, and repair. In a model of bilateral kidney IRI in mice, we elucidate an intricate relationship between CO and purinergic signaling involving increased CD39 ectonucleotidase expression, decreased expression of Adora1, with concomitant increased expression of Adora2a/2b. This response is linked to a >20-fold increase in expression of the circadian rhythm protein Period 2 (Per2) and a fivefold increase in serum erythropoietin (EPO), both of which contribute to abrogation of kidney IRI. CO is ineffective against IRI in Cd39−/− and Per2−/− mice or in the presence of a neutralizing antibody to EPO. Collectively, these data elucidate a cellular signaling mechanism whereby CO modulates purinergic responses and circadian rhythm to protect against injury. Moreover, these effects involve CD39- and adenosinergic-dependent stabilization of Per2. As CO also increases serum EPO levels in human volunteers, these findings continue to support therapeutic use of CO to treat IRI in association with organ transplantation, stroke, and myocardial infarction.


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