Effects Of Carbon Monoxide-releasing Molecule-2 Research Articles

Carbon monoxide-releasing molecule-2 protects intestinal mucosal barrier function by reducing epithelial tight-junction damage in rats undergoing cardiopulmonary resuscitation

BackgroundIschemia-reperfusion injury (IRI) to the small intestine is associated with the development of systemic inflammation and multiple organ failure after cardiopulmonary resuscitation (CPR). It has been reported that exogenous carbon monoxide (CO) reduces IRI. This study aimed to assess the effects of carbon monoxide-releasing molecule-2 (CORM-2) on intestinal mucosal barrier function in rats undergoing CPR. MethodsWe established a rat model of asphyxiation-induced cardiac arrest (CA) and resuscitation to study intestinal IRI, and measured the serum levels of intestinal fatty acid-binding protein. Morphological changes were investigated using light and electron microscopes. The expression levels of claudin 3 (CLDN3), occludin (OCLN), zonula occludens 1 (ZO-1), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), and nuclear factor kappa B (NF-κB) p65 were detected by western blotting. ResultsCompared with the sham-operated group, histological changes and transmission electron microscopy revealed severe intestinal mucosal injury in the CPR and inactive CORM-2 (iCORM-2) groups. In contrast, CORM-2 alleviated intestinal IRI. CORM-2, unlike iCORM-2, markedly decreased the Chiu's scores (2.38 ± 0.38 vs. 4.59 ± 0.34; P < 0.05) and serum intestinal fatty acid-binding protein level (306.10 ± 19.22 vs. 585.64 ± 119.84 pg/mL; P < 0.05) compared with the CPR group. In addition, CORM-2 upregulated the expression levels of tight junction proteins (CLDN3, OCLN, and ZO-1) (P < 0.05) and downregulated those of IL-10, TNF-α, and NF-кB p65 (P < 0.05) in the ileum tissue of rats that received CPR. ConclusionsCORM-2 prevented intestinal mucosal damage as a result of IRI during CPR. The underlying protective mechanism was associated with inhibition of ischemia-reperfusion-induced changes in intestinal epithelial permeability and inflammation in intestinal tissue.

CORM-2 Pretreatment Attenuates Inflammation-mediated Islet Dysfunction

During the process of human islet isolation a cascade of stressful events are triggered and negatively influence islet yield, viability, and function, including the production of proinflammatory cytokines and activation of apoptosis. Carbon monoxide-releasing molecule 2 (CORM-2) is a donor of carbon monoxide (CO) and can release CO spontaneously. Accumulating studies suggest that CORM-2 exerts cytoprotective and anti-inflammatory properties. However, the effect of CORM-2 on islet isolation is still unclear. In this study, we found that CORM-2 pretreatment significantly decreased the expression of critical inflammatory genes, including tissue factor, intercellular adhesion molecule-1, chemokine (C-C motif) ligand 2, C-X-C motif chemokine 10, Toll-like receptor 4, interleukin-1β, interleukin-6, and tumor necrosis factor-α (TNF-α). The isolated islets of the CORM-2 pretreatment group showed reduced apoptotic rate, improved viability, and higher glucose-stimulated insulin secretion, and functional gene expression in comparison to control group. Importantly, CORM-2 pretreatment prevented the impairment caused by TNF-α, evidenced by the improved glucose-stimulated index and transplantation outcomes. The present study demonstrated the anti-inflammatory property of CORM-2 during human islet isolation, and we suggest that CORM-2 pretreatment is an appealing treatment to mitigate inflammation-mediated islet dysfunction during isolation and culture ex vivo and to preserve long-term islet survival and function.

Protective effects of carbon monoxide-releasing molecule-2 on the barrier function of intestinal epithelial cells.

ObjectiveTo investigate the protective effects and mechanisms of carbon monoxide-releasing molecule-2 (CORM-2) on barrier function of intestinal epithelial cells.Materials and MethodsAfter pre-incubation with CORM-2 for 1 hour, cultured intestinal epithelial IEC-6 cells were stimulated with 50 µg/ml lipopolysaccharides (LPS). Cytokines levels in culture medium were detected using ELISA kits. Trans-epithelial electrical resistance (TER) of IEC-6 cell monolayers in Transwells were measured with a Millipore electric resistance system (ERS-2; Millipore) and calculated as Ω/cm2 at different time points after LPS treatment. The permeability changes were also measured using FITC-dextran. The levels of tight junction (TJ) proteins (occludin and ZO-1) and myosin light chain (MLC) phosphorylation were detected using Western blotting with specific antibodies. The subsequent structural changes of TJ were visualized using transmission electron microscopy (TEM).ResultsCORM-2 significantly reduced LPS-induced secretion of TNF-α and IL-1β. The LPS-induced decrease of TER and increase of permeability to FITC-dextran were inhibited by CORM-2 in a concentration dependent manner (P<0.05). LPS-induced reduction of tight junction proteins and increase of MLC phosphorylation were also attenuated. In LPS-treated cells, TEM showed diminished electron-dense material and interruption of TJ and desmosomes between the apical lateral margins of adjoining cells, which were prevented by CORM-2 treatment.ConclusionsThe present study demonstrates that CORM-2, as a novel CO-releasing molecule, has ability to protect the barrier function of LPS-stimulated intestinal epithelial cells. Inhibition of inflammatory cytokines release, restoration of TJ proteins and suppression of MLC phosphorylation are among the protective effects of CORM-2.

Mechanism(s) involved in carbon monoxide-releasing molecule-2-mediated cardioprotection during ischaemia-reperfusion injury in isolated rat heart

The purpose of the present study was to determine the mechanism(s) involved in carbon monoxide-releasing molecule-2, carbon monoxide-releasing molecule-2-induced cardioprotection. We used the transition metal carbonyl compound carbon monoxide-releasing molecule-2 that can act as carbon monoxide donor in cardiac ischaemia-reperfusion injury model using isolated rat heart preparation. Langendorff's perfused rat hearts when treated with carbon monoxide-releasing molecule-2 (50 μM) for 10 min before global ischaemia exhibited significant reduction in postischaemic levels of myocardial injury markers, creatine kinase and lactate dehydrogenase in coronary effluent. Similarly, pretreatment with carbon monoxide-releasing molecule-2 showed significantly improved postischaemic recovery of heart rate, coronary flow rate, cardiodynamic parameters and reduced infarct size as compared to vehicle control hearts. Perfusion with p38 mitogen-activated protein kinase inhibitor, SB203580, a specific inhibitor of α and β isoform, before and concomitantly with carbon monoxide-releasing molecule-2 treatment abolished carbon monoxide-releasing molecule-2-induced cardioprotection. However, p38 mitogen-activated protein kinase alpha inhibitor, SCIO-469, was unable to inhibit the cardioprotective effect of carbon monoxide-releasing molecule-2. Furthermore, protective effect of carbon monoxide-releasing molecule-2 was significantly inhibited by the protein kinase C inhibitor, chelerythrine, when added before and concomitantly with carbon monoxide-releasing molecule-2. It was also observed that, perfusion with phosphatidylinositol 3-kinase inhibitor, wortmannin, before and concomitantly with carbon monoxide-releasing molecule-2 was not able to inhibit carbon monoxide-releasing molecule-2-induced cardioprotection. Interestingly, we observed that wortmannin perfusion before ischaemia and continued till reperfusion significantly inhibited carbon monoxide-releasing molecule-2-mediated cardioprotection. Our findings suggest that the carbon monoxide-releasing molecule-2 treatment may activate the p38 mitogen-activated protein kinase β and protein kinase C pathways before ischaemia and phosphatidylinositol 3-kinase pathway during reperfusion which may be responsible for the carbon monoxide-releasing molecule-2-mediated cardioprotective effect.

Beneficial effects of carbon monoxide-releasing molecule-2 (CORM-2) on acute doxorubicin cardiotoxicity in mice: Role of oxidative stress and apoptosis

Doxorubicin (DXR) has been used in variety of human malignancies for decades. Despite its efficacy in cancer, clinical usage is limited because of its cardiotoxicity, which has been associated with oxidative stress and apoptosis. Carbon monoxide-releasing molecules (CORMs) have been shown to reduce the oxidative damage and apoptosis. The present study investigated the effects of CORM-2, a fast CO-releaser, against DXR-induced cardiotoxicity in mice using biochemical, histopathological and gene expression approaches. CORM-2 (3, 10 and 30 mg/kg/day) was administered intraperitoneally (i.p.) for 10 days and terminated the study on day 11. DXR (20 mg/kg, i.p.) was injected before 72 h of termination. Mice treated with DXR showed cardiotoxicity as evidenced by elevation of serum creatine kinase (CK) and lactate dehydrogenase (LDH), tissue malondialdehyde (MDA), caspase-3 and decrease the level of total antioxidant status (TAS) in heart tissues. Pre- and post-treatment with CORM-2 (30 mg/kg, i.p.) elicited significant improvement in CK, LDH, MDA, caspase-3 and TAS levels. Histopathological studies showed that cardiac damage with DXR has been reversed with CORM-2 + DXR treatment. There was dramatic decrease in hematological count in DXR-treated mice, which has been improved with CORM-2. Furthermore, there was also elevation of mRNA expression of heme oxygenase-1, hypoxia inducible factor-1 alpha, vascular endothelial growth factor and decrease in inducible-nitric oxide synthase expression upon treatment with CORM-2 that might be linked to cardioprotection. These data suggest that CORM-2 treatment provides cardioprotection against acute doxorubicin-induced cardiotoxicity in mice and this effect may be attributed to CORM-2-mediated antioxidant and anti-apoptotic properties.

The antifibrinolytic effects of carbon monoxide-releasing molecule-2 are fibrin and α2-antiplasmin dependent

Carbon monoxide derived from a carbon monoxide-releasing molecule [tricarbonyldichlororuthenium (II) dimer; CORM-2] has been recently demonstrated to diminish tissue-type plasminogen activator (tPA)-mediated fibrinolysis of plasma thrombi via enhancement of alpha2-antiplasmin-plasmin interactions. The goal of this study was to confirm this mechanism by comparing tPA-mediated fibrinolysis with fibrin-independent, alpha2-antiplasmin-resistant streptokinase-mediated fibrinolysis in CORM-2 exposed plasma. Normal plasma was exposed to 0 or 100 micromol/l CORM-2, with coagulation activated with tissue factor and fibrinolysis initiated with 100 U/ml tPA or 50 U/ml streptokinase. Thrombus growth/disintegration kinetics were monitored with thrombelastography until clot lysis time occurred. Unlike tPA-lysed clots, streptokinase-exposed thrombi demonstrated no significant CORM-2-mediated prolongation of clot growth time or clot lysis time. In contrast, streptokinase-mediated lysis did not significantly change the CORM-2-mediated percentage increase in the maximum rate of clot growth or maximum rate of clot lysis compared with tPA-exposed thrombi. CORM-2 likely attenuates fibrinolysis by a fibrin-dependent/alpha2-antiplasmin-dependent mechanism. Additional molecular investigation (e.g., mass spectroscopy) is planned to further elucidate how CORM-2 modifies fibrinogen/fibrin.