CME-induced Myocardial Injury Research Articles

Shexiang tongxin dropping pill alleviates myocardial injury induced by coronary microembolization by down-regulating APOC1 to inhibit STAT3 signaling pathway.

This study determines to validate the mechanism of Shexiang Tongxin dropping pill (STDP) in attenuating coronary microembolization (CME) induced myocardial injury. CME rat models were established and underwent corresponding treating. Gene chip analysis was performed in rat myocardial tissues for GO and KEGG enrichment analysis. The differentially expressed genes were detected by qRT-PCR. H&E staining and ELISA were used for pathological analysis and detection of troponin (cTnI) and Creatine Kinase Isoenzyme (CK-MB). Lipopolysaccharide (LPS) treated primary cardiomyocytes were used to mimic inflammatory in vitro models. Cell viability and apoptosis of cardiomyocytes were determined by MTT and flow cytometry. The expressions of inflammatory cytokines, apoptotic proteins and proteins related to the STAT3 signal pathway were detected by western blot. APOC1 mRNA expression was detected by qRT-PCR. Immunofluorescence (IF) was used for subcellular localization of p-STAT3 and the binding of APOC1 with STAT3 was verified using Co-IP. STDP can attenuate myocardial injury in CME rat models, and lead to decreased expression of APOC1 and suppressed STAT3 signal pathway. In vitro models found STDP can suppress the cell viability and cell apoptosis of primary cardiomyocytes, in addition to suppressing the secretions of IL-6, IL-1β and TNF-α, while the protective effect of STDP can be reversed by overexpression of APOC1. Co-IP found that APOC1 can bind STAT3 directly. APOC1 can increase p-STAT3 expression in the nucleus to activate the STAT3 signal pathway. STDP can suppress APOC1 and STAT3 signal pathway to inhibit inflammation and cell apoptosis of cardiomyocytes. APOC1 may be one of the key regulatory factors in CME-induced myocardial injury.

Colchicine ameliorates myocardial injury induced by coronary microembolization through suppressing pyroptosis via the AMPK/SIRT1/NLRP3 signaling pathway

BackgroundCoronary microembolization(CME)is a common complication in acute coronary syndrome and percutaneous coronary intervention, which is closely related to poor prognosis. Pyroptosis, as an inflammatory programmed cell death, has been found to be associated with CME-induced myocardial injury. Colchicine (COL) has potential benefits in coronary artery disease due to its anti-inflammatory effect. However, the role of colchicine in pyroptosis-related CME-induced cardiomyocyte injury is unclear. This study was carried out to explore the effects and mechanisms of colchicine on myocardial pyroptosis induced by CME.MethodsThe CME animal model was constructed by injecting microspheres into the left ventricle with Sprague-Dawley rats, and colchicine (0.3 mg/kg) pretreatment seven days before and on the day of modeling or compound C(CC)co-treatment was given half an hour before modeling. The study was divided into 4 groups: Sham group, CME group, CME + COL group, and CME + COL + CC group (10 rats for each group). Cardiac function, serum myocardial injury markers, myocardial histopathology, and pyroptosis-related indicators were used to evaluate the effects of colchicine.ResultsColchicine pretreatment improved cardiac dysfunction and reduced myocardial injury induced by CME. The main manifestations were the improvement of left ventricular systolic function, the decrease of microinfarction area, and the decrease of mRNA and protein indexes related to pyroptosis. Mechanistically, colchicine increased the phosphorylation level of adenosine monophosphate-activated protein kinase (AMPK), promoted the expression of silent information regulation T1 (SIRT1), and inhibited the expression of NOD-like receptor pyrin containing 3 (NLRP3) to reduce myocardial pyroptosis. However, after CC co-treatment with COL, the effect of colchicine was partially reversed.ConclusionColchicine improves CME-induced cardiac dysfunction and myocardial injury by inhibiting cardiomyocyte pyroptosis through the AMPK/SIRT1/NLRP3 signaling pathway.

Atorvastatin attenuates ferroptosis-dependent myocardial injury and inflammation following coronary microembolization via the Hif1a/Ptgs2 pathway.

Objectives: Coronary microembolization (CME) represents a serious periprocedural complication after percutaneous coronary intervention. Ferroptosis has been identified in multiple cardiovascular diseases. In this study, we aimed to investigate the effects of atorvastatin (ATV) on ferroptosis and inflammation following CME and elucidate the underlying mechanism. Methods: We established a rat model of CME by injecting microspheres into the left ventricle. Deferoxamine (DFO), a selective ferroptosis inhibitor, or ATV was pretreated before modeling. Cardiac function and cardiac troponin T (cTnT) levels were detected. Levels of ferroptosis-associated genes, malondialdehyde (MDA), glutathione (GSH), and ferrous iron (Fe2+) were measured to validate ferroptosis. Levels of tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) were assayed to determine the inflammation. Chromatin immunoprecipitation was performed to determine the binding of hypoxia-inducible factor 1 subunit alpha (Hif1a) to the promoter of prostaglandin-endoperoxide synthase-2 (Ptgs2). Results: Ferroptosis and inflammation were induced following CME with increased levels of MDA (∼2.5 fold, p < 0.01), Fe2+ (∼1.5 fold, p < 0.01), TNF-α, and IL-1β and decreased GSH levels (∼42%, p < 0.01). Meanwhile, the level of Ptgs2 was significantly increased, while those of glutathione peroxidase 4 (Gpx4) and solute carrier family 7 member 11 (Slc7a11) were decreased. The level of cTnT was increased by 7-fold (p < 0.01). Left ventricular ejection fraction (LVEF) was significantly reduced (∼85% in the sham group versus ∼45% in the CME group, p < 0.01). DFO or Ptgs2 silencing inhibited the increase of MDA, Ptgs2, TNF-α, and IL-1β, and induced the levels of GSH and Gpx4, followed by reduction in cTnT levels by approximately 50% (p < 0.01). LVEF was improved by approximately 2 fold (p < 0.01). Mechanistically, the transcription factor Hif1a bound to the promoter of Ptgs2 and upregulated its expression. In addition, ATV inhibited the activation of the Hif1a/Ptgs2 axis and attenuated cardiac ferroptosis and inflammation, thus ameliorating CME-induced myocardial injury (LVEF, ∼34% elevation; cTnT, ∼1.8 fold decrease, p < 0.01). Conclusion: Atorvastatin ameliorates ferroptosis-mediated myocardial injury and inflammation following CME via the Hif1a/Ptgs2 pathway.

Nicorandil protects against coronary microembolization-induced myocardial injury by suppressing cardiomyocyte pyroptosis via the AMPK/TXNIP/NLRP3 signaling pathway

BackgroundCoronary microembolization (CME) is a common and intractable complication of coronary revascularization, which leads to perioperative myocardial injury, cardiac dysfunction, and poor prognosis. Nicorandil is widely used for the management of ischemic heart diseases, but the cardioprotective effects of nicorandil beyond anti-angina in CME-induced myocardial injury are worthy of further exploration. Therefore, the present study investigated the effect of nicorandil on CME-induced cardiomyocyte pyroptosis and explored the underlying mechanism. MethodsA rat model of CME was established via the injection of microspheres into the left ventricle. A cell model of H9c2 cardiomyocytes stimulated by lipopolysaccharide (LPS) and hypoxia mimicked the microenvironment induced by CME. Nicorandil or the adenosine monophosphate-activated protein kinase (AMPK)-specific inhibitor compound C (CC) was administered before CME induction and cell modeling. Cardiac function, histological alterations in the myocardium, myocardial injury biomarkers in serum and cell culture supernatant, cell viability, adenosine triphosphate (ATP) level, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, reactive oxygen species (ROS) activity, mitochondrial membrane potential, and pyroptosis-associated index were assessed after the animal and cell modeling of CME. ResultsNicorandil pretreatment attenuated cardiac dysfunction and myocardial injury following CME. Nicorandil also alleviated oxidative stress and mitochondrial damage. Moreover, nicorandil promoted AMPK activation, reduced the expression of thioredoxin-interacting protein (TXNIP), inhibited the activation of the NOD-like receptor pyrin containing 3 (NLRP3) inflammasome, and mitigated cardiomyocyte pyroptosis. However, co-treatment with CC reversed the cardioprotective effects of nicorandil. ConclusionNicorandil pretreatment inhibits cardiomyocyte pyroptosis and alleviates CME-induced myocardial injury via the AMPK/TXNIP/NLRP3 signaling pathway.

Human Urinary Kallidinogenase Pretreatment Inhibits Myocardial Inflammation and Apoptosis after Coronary Microembolization by Activating PI3K/Akt/FoxO1 Axis.

As a fatal cardiovascular complication, coronary microembolization (CME) results in severe cardiac dysfunction and arrhythmia associated with myocardial inflammation and apoptosis. Human urinary kallidinogenase (HUK) can provide a protective function for cardiomyocytes by improving microcirculation. However, the therapeutic effects and underlying mechanisms of HUK in CME-induced myocardial injury remain unclear. We evaluated the effect of HUK on cardiac protection in a rat model of CME and whether it could restrain myocardial inflammation and apoptosis, and alleviate CME-induced myocardial injury. We established the CME model by injecting 42 μm inert plastic microspheres into the left ventricle of rats in advance, then the rats were randomly and equally divided into CME, CME + HUK (the dose of HUK at 0.016 PNA/kg/day), CME + HUK + LY (the dose of LY294002 at 10 mg/kg, 30 minutes before modeling), and Sham operation groups. Cardiac function, the serum levels of myocardial injury biomarkers, myocardial inflammation and apoptosis-related genes were measured; and the myocardial histopathological examination was performed at 12 h after the operation. The results revealed that HUK effectively reducing myocardial inflammation, apoptosis, and myocardial infarction area; and improving CME-induced cardiac injury by activating the PI3K/Akt/FoxO1 axis. In addition, these cardioprotective effects can be reduced by the PI3K specific inhibitor LY294002, suggesting that the aforementioned protective effects may be related to activation of the PI3K/Akt/FoxO1 axis. HUK seems to control inflammatory infiltration and cardiomyocyte apoptosis significantly to improve CME-induced cardiac injury via regulating the PI3K/Akt/FoxO1 axis.

Upregulation of miR-29b-3p alleviates coronary microembolization-induced myocardial injury via regulating BMF and GSK-3β.

Coronary microembolization (CME) is an intractable complication results from acute coronary syndrome. CME-induced myocardial apoptosis was associated with progressive cardiac contractile dysfunction. miR-29b-3p has been reported implicated in variety cardiovascular diseases, but its function in CME-induced myocardial injury is yet unknown. Herein, a rat model of CME was established by injecting microspheres into the left ventricle and found that the expression level of miR-29b-3p was markedly decreased in the CME rat heart tissues. By using echocardiography, CD31 immunohistochemistry staining, hematoxylin basic fuchsin picric acid (HBFP) staining, TUNEL staining, and western blotting analysis after CME, it was found that upregulating miR-29b-3p improved cardiac dysfunction, promoted angiogenesis, decreased myocardial microinfarct area, and inhibited myocardial apoptosis. Additionally, miR-29b-3p inhibition can reverse the protective benefits of miR-29b-3p overexpression. Mechanistically, the target genes of miR-29b-3p were identified as glycogen synthase kinase 3 (GSK-3β) and Bcl-2 modifying factor (BMF) by bioinformatics analysis and luciferase reporter experiment. Overall, our findings imply that induction of miR-29b-3p, which negatively regulates GSK-3β and BMF expression, attenuates CME-induced myocardial injury, suggesting a novel potential therapeutic target for cardioprotective after CME.

Possible implication of miR-142-3p in coronary microembolization induced myocardial injury via ATXN1L/HDAC3/NOL3 axis.

This study aims to explore the mechanism underlying miR-142-3p regulating myocardial injury induced by coronary microembolization (CME) through ATXN1L. miR-142-3p overexpression or ATXN1L knockout adenovirus vectors were injected into rats before CME treatment. Cardiac functions were examined by echocardiography, and pathologies of myocardial tissues were assessed. Then, serum cTnI and IL-1β contents and concentrations of IL-1β and IL-18 in cell supernatant were measured. Immunofluorescence determined the localization of histone deacetylase 3 (HDAC3). The interaction between miR-142-3p and ATXN1L as well as the binding between HDAC3 and histone 3 (H3) was identified. The binding of ATXN1L and HDAC3 to NOL3 promoter was verified using ChIP. The levels of ATXN1L, NOL3, and miR-142-3p as well as apoptosis- and pyroptosis-related proteins and acetyl-histone 3 (ac-H3) were evaluated. CME treatment impaired the cardiac functions in rats and increased cTnI content. CME rats showed microinfarction foci in myocardial tissues. After CME treatment, miR-142-3p and NOL3 were modestly expressed while ATXN1L content was elevated, in addition to increases in apoptosis and pyroptosis. miR-142-3p overexpression or ATXN1L knockout alleviated CME-induced myocardial injury, cardiomyocyte apoptosis, and pyroptosis in myocardial tissues. miR-142-3p regulated ATXN1L expression in a targeted manner. In the cellular context, miR-142-3p overexpression attenuated apoptosis and pyroptosis in cardiomyocytes, which was partly counteracted by ATXN1L overexpression. ATXN1L functioned on cardiomyocytes by promoting deacetylation of H3 through HDAC3 and thus inhibited NOL3 expression. Inhibition of HDAC3 or overexpression of NOL3 ameliorated the promotive effects of ATXN1L on cardiomyocyte apoptosis and pyroptosis. In vivo and in vitro evidence in this study supported that miR-142-3p could attenuate CME-induced myocardial injury via ATXN1L/HDAC3/NOL3. HIGHLIGHTS: CME model witnessed aberrant expression of miR-142-3p, ATXN1L, and NOL3; miR-142-3p negatively regulated ATXN1L; miR-142-3p mediated CME-induced myocardial injury through ATXN1L; ATXN1L promoted deacetylation of H3 through HDAC3 and thus inhibited NOL3 expression; ATXN1L acted on cardiomyocyte apoptosis and pyroptosis through HDAC3/NOL3 axis.

Long non-coding RNA Sox2OT promotes coronary microembolization-induced myocardial injury by mediating pyroptosis.

ObjectiveAs a common complication of coronary microembolization (CME), myocardial injury (MI) implies high mortality. Long non‐coding RNAs (lncRNAs) are rarely studied in CME‐induced MI. Herein, this study intended to evaluate the role of lncRNA Sox2 overlapping transcript (Sox2OT) in CME‐induced MI.MethodsThe CME rat models were successfully established by injection of microemboli. Rat cardiac functions and MI were observed by ultrasonic electrocardiogram, HE staining, and HBFP staining. Functional assays were utilized to test the inflammatory responses, oxidative stress, and pyroptosis using reverse transcription quantitative polymerase chain reaction, Western blotting, immunohistochemistry, immunofluorescence, and ELISA. Dual‐luciferase reporter gene assay and RNA immunoprecipitation were conducted to clarify the targeting relations between Sox2OT and microRNA (miRNA)‐23b and between miR‐23b and toll‐like receptor 4 (TLR4).ResultsRat CME disrupted the cardiac functions and induced inflammatory responses and oxidative stress, and activated the nuclear factor‐kappa B (NF‐κB) pathway and pyroptosis (all P < 0.05). An NF‐κB inhibitor downregulated the NF‐κB pathway, reduced pyroptosis, and relieved cardiomyocyte injury and pyroptosis. Compared with the sham group (1.05 ± 0.32), lncRNA Sox2OT level (4.41 ± 0.67) in the CME group was elevated (P < 0.05). Sox2OT acted as a competitive endogenous RNA (ceRNA) of miR‐23b to regulate TLR4. Silencing of Sox2OT favoured miR‐23b binding to 3′UTR of TLR4 mRNA leading to suppressed TLR4‐mediated NFKB signalling and pyroptosis in myocardial tissues harvested from CME rat models. In addition, miR‐23b overexpression could supplement the cytosolic miR‐23b reserves to target TLR‐4 and partially reverse Sox2OT‐mediated pyroptosis in LPS‐treated H9C2 cells.ConclusionsThis study supported that silencing Sox2OT inhibited CME‐induced MI by eliminating Sox2OT/miR‐23b binding and down‐regulating the TLR4/NF‐κB pathway. This investigation may provide novel insights for the treatment of CME‐induced MI.

Resveratrol Pretreatment Inhibits Myocardial Apoptosis in Rats Following Coronary Microembolization via Inducing the PI3K/Akt/GSK-3β Signaling Cascade.

PurposeCoronary microembolization (CME) is associated with progressive cardiac dysfunction, myocardial inflammation, and apoptosis. Resveratrol (RES) has a considerable role in cardioprotection. However, the contribution and possible mechanisms of RES in CME have not been clearly understood.MethodsIn the current study, 40 SD rats were randomly selected and categorized into various groups including CME, CME + resveratrol (CME + RES), CME + resveratrol+ LY294002 (CME + RES + LY), and sham groups (10 animals in each group). The inert plastic microspheres (42 μm) were injected into the rats’ left ventricle for developing the CME model. Then resveratrol (25 mg/kg/d) was given to the rats in the CME + RES and CME + RES + LY groups for one week before CME induction. Furthermore, LY294002 (10 mg/kg) was intraperitoneally injected into the rats of the CME + RES + LY group 0.5 hours before CME modeling. The cardiac functions, serum levels of myocardial injury biomarkers, myocardial histopathology, and mRNA and proteins associated with myocardial apoptosis were all assessed 12 hours after surgery.ResultsThe results revealed that resveratrol pretreatment alleviated the CME-induced myocardial damage by improving cardiac dysfunction, and lowering the serum level of myocardial injury biomarkers, myocardial microinfarct size, and cardiomyocyte apoptotic index. Pretreatment with resveratrol reduced the level of proteins and mRNAs associated with the pro-apoptosis in myocardial tissues and increased the levels of proteins and mRNAs associated with the anti-apoptosis. Moreover, the combined treatment of resveratrol and LY294002 reversed the observed protective effects.ConclusionResveratrol can inhibit cardiomyocyte apoptosis, thus attenuating the CME-induced myocardial injury by triggering the PI3K/Akt/GSK-3β cascade.

MiR-200a-3p Attenuates Coronary Microembolization-Induced Myocardial Injury in Rats by Inhibiting TXNIP/NLRP3-Mediated Cardiomyocyte Pyroptosis.

Coronary microembolization (CME) commonly develops as a complication after percutaneous coronary intervention (PCI), and associated inflammation is a leading driver of myocardial damage. Cardiomyocyte loss in the context of ischemic myocardial disease has been linked to inflammatory pyroptotic cell death. Additionally, miR-200a-3p dysregulation has been linked to myocardial ischemia-reperfusion and many other pathological conditions. However, how miR-200a-3p impacts cardiomyocyte pyroptosis in the context of CME remains to be assessed. Herein, a rat model of CME was established via the injection of microembolic spheres into the left ventricle. When myocardial tissue samples from these rats were analyzed, miR-200a-3p levels were markedly decreased, whereas thioredoxin-interacting protein (TXNIP) levels were increased. The ability of miR-200a-3p to directly target TXNIP and to control its expression was confirmed via dual-luciferase reporter assay. Adeno-associated virus serotype 9-pre-miR-200a-3p (AAV-miR-200a-3p) construct transfection was then employed as a means of upregulating this miRNA in CME model rats. Subsequent assays, including echocardiography, enzyme-linked immunosorbent assays (ELISAs), hematoxylin-eosin (H&E) staining, hematoxylin-basic fuchsin-picric acid (HBFP) staining, TdT-mediated dUTP nick-end labeling (TUNEL) staining, immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting revealed that miR-200a-3p overexpression inhibited cardiomyocyte pyroptosis and alleviated CME-induced myocardial injury by inhibiting the TXNIP/NOD-like receptor family pyrin domain-containing 3 (NLRP3) pathway. The ability of miR-200a-3p to protect against CME-induced myocardial injury thus highlights a novel approach to preventing or treating such myocardial damage in clinical settings.

Downregulation of miR-181a-5p alleviates oxidative stress and inflammation in coronary microembolization-induced myocardial damage by directly targeting XIAP.

BACKGROUNDCoronary microembolization (CME) is a complicated problem that commonly arises in the context of coronary angioplasty. MicroRNAs play crucial roles in cardiovascular diseases. However, the role and mechanism of miR-181a-5p in CME-induced myocardial injury remains unclear.METHODSWe established CME rat models. Cardiac function was detected by echocardiography. Haematoxylin-basic fuchsin-picric acid staining was used to measure micro-infarction size. Serum samples and cell culture supernatants were evaluated via enzyme-linked immunosorbent assay. Cellular reactive oxygen species were determined by dichloro-dihydro-fluorescein diacetate assay, and the other oxidative stress related parameters were assayed by spectrophotometry. The dual-luciferase reporter (DLR) assay and RNA pulldown were conducted to validate the association between miR-181a-5p and X-linked inhibitor of apoptosis protein (XIAP). The expression of miR-181a-5p and XIAP mRNA were determined by quantitative reverse transcription polymerase chain reaction. Proteins were evaluated via immunoblotting. The viability of the cell was evaluated via cell counting kit-8 assay.RESULTSThe miR-181a-5p level was significantly increased in CME myocardial tissues. Downregulation of miR-181a-5p improved CME-induced cardiac dysfunction and alleviated myocardial oxidative stress and inflammatory injury, whereas miR-181a-5p exhibited the opposite effects. Then, the DLR assay and RNA pulldown results revealed that miR-181a-5p directly targeting on XIAP. The XIAP level was found to be remarkably decreased after CME. XIAP overexpression attenuated CME-induced myocardial oxidative stress and inflammatory injury. Finally, in vitro rescue experiments revealed that knockdown of XIAP could abolish the protective effects of miR-181a-5p knockdown on hypoxia-induced cardiomyocyte oxidative stress and inflammatory injury. CONCLUSIONSDownregulation of miR-181a-5p alleviates CME-induced myocardial damage by suppressing myocardial oxidative stress and inflammation through directly targeting XIAP.

Overexpression of lncRNA TUG1 Alleviates NLRP3 Inflammasome-Mediated Cardiomyocyte Pyroptosis Through Targeting the miR-186-5p/XIAP Axis in Coronary Microembolization-Induced Myocardial Damage.

Coronary microembolization (CME) is a complicated problem that commonly arises in the context of coronary angioplasty. The lncRNA taurine-up regulated gene 1 (TUG1), significantly contributes to cardiovascular diseases; however, its contribution to CME-induced myocardial damage remains elusive. Herein, we establish the rat CME model and investigate the role of TUG1 in CME. The cell viability was evaluated via CCK-8 assay. Serum and cell culture supernatant samples were evaluated via ELISA. The dual luciferase reporter (DLR) assay, RIP, and RNA-pull down were conducted to validate the associations between TUG1 and miR-186-5p as well as miR-186-5p and XIAP. The expression of TUG1, miR-186-5p, and XIAP mRNA were determined by RT-qPCR, and proteins were evaluated via immuneblotting. As a result, TUG1 and XIAP were significantly down-regulated, and the miR-186-5p level was found to be remarkably up-regulated in CME myocardial tissues. Overexpression of TUG1 alleviated CME-induced myocardial injury and pyroptosis, whereas TUG1 knockdown showed the opposite effects. The DLR assay, RIP, and RNA-pull down results reveal that TUG1 directly targets miR-186-5p and miR-186-5p directly targets XIAP. In vitro rescue experiments show that TUG1 overexpression alleviates LPS-caused cardiomyocyte injury and pyroptosis via sponging miR-186-5p and regulating XIAP, and depression of miR-186-5p reduces LPS-induced cardiomyocyte injury and pyroptosis by targeting XIAP. Concludingly, the overexpression of TUG1 alleviates NLRP3 inflammasome-mediated cardiomyocyte pyroptosis through targeting the miR-186-5p/XIAP axis in CME-induced myocardial injury.

Breviscapine Pretreatment Inhibits Myocardial Inflammation and Apoptosis in Rats After Coronary Microembolization by Activating the PI3K/Akt/GSK-3β Signaling Pathway.

PurposeCoronary microembolization (CME) can cause myocardial inflammation, apoptosis and progressive cardiac dysfunction. On the other hand, breviscapine exerts a significant cardioprotective effect in many cardiac diseases although its role and the potential mechanisms in CME remain unclear. Therefore, the present study aimed to ascertain whether pretreatment with breviscapine could improve CME-induced myocardial injury by alleviating myocardial inflammation and apoptosis. The possible underlying mechanisms were also explored.MethodsIn this study, 48 Sprague-Dawley (SD) rats were randomly assigned to the CME, CME + breviscapine (CME + BE), CME + breviscapine + LY294002 (CME + BE + LY) and sham groups (12 rats per group). In addition, the CME model was successfully established by injecting 42 μm inert plastic microspheres into the left ventricle of rats. Rats in the CME + BE and CME + BE + LY groups received 40 mg/kg/d of breviscapine for 7 days before inducing CME. Moreover, rats in the CME + BE + LY group were intraperitoneally injected with the phosphoinositide 3-kinase (PI3K) specific inhibitor, LY294002 (10 mg/kg) 30 minutes before CME modeling. 12 h after surgery, the study measured cardiac function, the serum levels of markers of myocardial injury, myocardial inflammation-associated mRNAs and proteins, myocardial apoptosis-associated mRNAs and proteins and conducted myocardial histopathology.ResultsThe findings demonstrated that pretreatment with breviscapine alleviated myocardial injury following CME by improving cardiac dysfunction, decreasing the serum levels of markers of myocardial injury, reducing the size of myocardial microinfarct and lowering the cardiomyocyte apoptotic index. More importantly, pretreatment with breviscapine resulted to a decrease in the levels of inflammatory and pro-apoptotic mRNAs and proteins in myocardial tissues and there was an increase in the levels of anti-apoptotic mRNAs and proteins. However, these protective effects were eliminated when breviscapine was combined with LY294002.ConclusionThe findings from this study indicated that breviscapine may inhibit myocardial inflammation and apoptosis by regulating the PI3K/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway, thereby ameliorating CME-induced cardiac dysfunction and reducing myocardial injury.

Nicorandil inhibits cardiomyocyte apoptosis and improves cardiac function by suppressing the HtrA2/XIAP/PARP signaling after coronary microembolization in rats.

Cardiomyocyte apoptosis is a key factor in the deterioration of cardiac function after coronary microembolization (CME). Nicorandil (NIC) affects myocardial injury, which may be related to the inhibition of apoptosis. However, the specific mechanism of cardioprotection has not been elucidated. Therefore, we analyzed the impact of NIC on cardiac function in rats subjected to CME and its effect on the high‐temperature requirement peptidase 2/X‐linked inhibitor of apoptosis protein/poly ADP‐ribose polymerase (HtrA2/XIAP/PARP) pathway. Sprague Dawley rats were divided into four groups: Sham, CME, CME + NIC, and CME + UCF. Echocardiography was performed 9 hours after CME. Myocardial injury markers were evaluated in blood samples, and the heart tissue was collected for hematoxylin‐eosin staining, hematoxylin basic fuchsin picric acid staining staining, TdT‐mediated DUTP nick end labeling (TUNEL) staining, Western blot analysis of the HtrA2/XIAP/PARP pathway, and transmission electron microscopy. NIC ameliorated cardiac dysfunctioncaused by CME and reduced serum levels of CK‐MB and LDH. In addition, NIC decreased myocardial microinfarct size and apoptotic index. NIC reduced the Bax/Bcl‐2 ratio, levels of cleaved caspase 3/9, cytoplasmic HtrA2, and cleaved PARP, and increased the level of XIAP. The effects of NIC were similar to those of the HtrA2 inhibitor, UCF101. This study demonstrated that NIC reduces CME‐induced myocardial injury, reduces mitochondrial damage, and improves myocardial function. The reduction in cardiomyocyte apoptosis by NIC may be mediated by the HtrA2/XIAP/PARP signaling pathway.

Levosimendan Attenuates Myocardial Injury Induced by Coronary Microembolization in Swine by Inhibiting Myocardial Inflammation and Apoptosis

Aims: In addition to its cardiotonic effect, Levosimendan (Levo) has been thought to have multiple cardiovascular benefits, including anti-inflammatory and anti-apoptotic effects. The present study was undertaken to determine whether the Levo pretreatment could attenuate myocardial apoptosis and inflammation and improve cardiac function in a swine model of coronary microembolization (CME). Materials and Methods: A total of 15 swine were randomly and equally divided into a sham-operated (control) group, CME group, and CME plus Levo group. Swine CME was induced by intracoronary injection of inertia plastic microspheres (42 μm diameter) into the left anterior descending (LAD) coronary artery, with or without pretreatment of Levo. Echocardiological measurements, a pathological examination, Terminal-deoxynucleoitidyl Transferase-Mediated dUTP Nick End-Labeling (TUNEL) staining, H and E staining, and Western blotting were performed to assess the functional, morphological, and molecular effects in CME. Results: The expression levels of caspase-3 and tumor necrosis factor-α (TNF-α) were increased in cardiomyocytes following CME. Downregulation of caspase-3 and TNF-α with Levo pretreatment was associated with improved cardiac troponin I (cTnI) and high sensitivity C-reactive protein. In addition, through Pearson correlation analysis, the left ventricular ejection fraction was negatively correlated with caspase-3, TNF-α, and cTnI. Conclusion: This study demonstrated that Levo pretreatment could significantly inhibit CME-induced myocardial apoptosis and inflammation and improve cardiac function. The data generated from this study provide a rationale for the development of myocardial apoptosis and inflammation-based therapeutic strategies for CME-induced myocardial injury.

Aloperine Activates the PI3K/Akt Pathway and Protects Against Coronary Microembolisation-Induced Myocardial Injury in Rats

Background: Coronary microembolisation (CME)-induced myocardial apoptosis is a key factor in progressive cardiac dysfunction. Aloperine (ALO) plays a protective role in the cardiovascular system, but its role and the mechanism ­underlying its protection against CME are unclear. Therefore, we aimed to verify whether ALO has a protective effect against CME-induced myocardial injury, as well as whether this effect has a relationship with regulation of the PI3K/Akt pathway for rats. Methods: Forty Sprague-Dawley rats were randomised into 4 equal groups: CME, CME + ALO, CME + ALO + LY294002 (LY) and a Sham group. Twelve hours after surgery, the rats’ cardiac function, apoptosis index, microinfarct and serum cardiac-troponin I (cTnI) level were measured. Levels of p-Akt, total Akt, Bcl-2, Bax and cleaved caspase-3 were detected. Results: ALO improved cardiac dysfunction induced by CME, while also decreasing serum levels of cTnI and microinfarct areas. In addition, ALO inhibited myocardial apoptosis, which may have been partially as a result of downregulated cleaved caspase-3 and Bax, upregulated Bcl-2 and increased protein levels in phosphorylated Akt. However, these ALO effects were blocked if ALO was administered along with LY. Conclusions: ALO can inhibit cardiomyocyte apoptosis and consequently attenuate CME-induced myocardial injury. These functions are realised by activating PI3K/Akt signalling pathway.

Ligustrazine Attenuates Myocardial Injury Induced by Coronary Microembolization in Rats by Activating the PI3K/Akt Pathway.

Background/Aims Coronary microembolization- (CME-) induced myocardial injury and progressive cardiac dysfunction are mainly caused due to CME-induced myocardial local inflammatory response and myocardial apoptosis. Ligustrazine plays an important protective role in multiple cardiovascular diseases, but its role and the protection mechanism in CME is unclear. This study hypothesized that ligustrazine attenuates CME-induced myocardial injury in rats. This study also explored the mechanism underlying this attenuation. Methods Forty SD rats were randomly divided into CME group, ligustrazine group, ligustrazine+LY294002 (ligustrazine+LY) group, and sham group (ten rats in each). In each group, the cardiac function, apoptotic index, serum c-troponin I (cTnI) level, inflammation [interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α)], and oxidative stress [nitric oxide (NO), superoxide dismutase (SOD), and malondialdehyde (MDA)] were determined. Western blotting was used to detect the proteins which are present in the PI3K/Akt pathway. Results Ligustrazine improved cardiac dysfunction induced by CME, increased serum NO and SOD activities, and decreased the serum level in IL-1β, MDA, cTnI, and TNF-α. Moreover, ligustrazine inhibited myocardial apoptosis, which is perhaps caused by the upregulated Bcl-2, the downregulated cleaved caspase-3 and Bax, and the increased protein level in endothelial nitric oxide synthase and phosphorylated Akt. These effects, however, were reduced if ligustrazine was coadministered with LY294002. Conclusions Ligustrazine attenuates CME-induced myocardial injury. The effects associated with this attenuation may be achieved by activating the myocardium PI3K/Akt signaling pathway.

The mechanism of miR-142-3p in coronary microembolization-induced myocardiac injury via regulating target gene IRAK-1

Coronary microembolization (CME) is a common complication seen during primary percutaneous coronary intervention (pPCI). CME-induced myocardiac inflammation is the primary cause of myocardiac injury. Dysregulated miR-142-3p has been implicated in multiple cardiovascular diseases and is significantly downregulated in CME-induced myocardial injury. However, the role of miR-142-3p in CME-induced myocardial injury is unclear. This study herein built a porcine CME model by infusing microembolization spheres into the left anterior descending branch via a microcatheter, and detected the downregulation of miR-142-3p in the myocardial tissues of CME pigs. Echocardiography, hematoxylin basic fuchsin picric acid (HBFP) staining, and western blotting of NF-κB p65, TNF-α, IL-1β, and IL-6 showed that the pharmacological overexpression of miR-142-3p using agomiR has improved cardiac function and attenuated CME-induced myocardiac inflammatory response, while its inhibition using antagomiR demonstrated inverse effects. Moreover, in vitro experiments demonstrated IRAK-1 as a direct target gene of miR-142-3p. Luciferase reporter assays, quantitative real-time polymerase chain reaction and western blotting demonstrated its effects in controlling the inflammation of cardiomyocytes. It is noteworthy that miR-142-3p was found to be decreased in the plasma of STEMI patients undergoing pPCI with no-reflow, indicating a potential clinical relevance of miR-142-3p. The receiver–operator characteristic curve indicated that plasma miR-142-3p might be an independent predictor of no-reflow during pPCI in patients with STEMI. Therefore, overexpression of miR-142-3p acts as a novel therapy for CME-induced myocardial injury.

MicroRNA-26a-5p affects myocardial injury induced by coronary microembolization by modulating HMGA1.

Coronary microembolization (CME) occurs when atherosclerotic plaque debris is detached during the treatment of acute coronary syndrome with Percutaneous Coronary Intervention (PCI). The complications of distal microvascular embolism, including local myocardial inflammation, are the main causes of myocardial damage and are a strong predictor of poor long-term prognosis and major cardiac adverse events. microRNAs (miRNAs) are involved in the pathophysiological processes of cardiovascular inflammatory diseases. Dysregulation of microRNA (miR)-26a-5p, in particular, is associated with a variety of cardiovascular diseases. However, the role of miR-26a-5p in CME-induced myocardial injury is unclear. In this study, we developed an animal model of CME by injecting microembolic balls into the left ventricle of rats and found that miR-26a-5p expression decreased in myocardial tissue in response. Using a miR-26a-5p mimic, echocardiography, hematoxylin-eosin staining, and Western blot analysis we found that the diminished cardiac function and myocardial inflammation induced by CME is alleviated by miR-26a-5p overexpression. Furthermore, our results show that inhibitors of miR-26a-5p have the opposite effect. In addition, in vitro experiments using real-time PCR, Western blot analysis, and a dual luciferase reporter gene show that HMGA1 is a target gene of miR-26a-5p. Thus, overexpression of miR-26a-5p could be a novel therapy to improve CME-induced myocardial damage.

Egr-1 is involved in coronary microembolization-induced myocardial injury via Bim/Beclin-1 pathway-mediated autophagy inhibition and apoptosis activation.

Coronary microembolization (CME) substantially reduces the clinical benefits of myocardial reperfusion therapy. Autophagy and apoptosis participate in the pathophysiological processes of almost all cardiovascular diseases, including CME-induced myocardial injury, but the precise underlying mechanisms remain unclear. In the present study, we observed that Egr-1 expression was substantially increased after CME modeling. Inhibition of Egr-1 expression through the targeted delivery of rAAV9-Egr-1-shRNA improved cardiac function and reduced myocardial injury. The microinfarct size was also significantly smaller in the Egr-1 inhibitor group than in the CME group. These benefits were partially reversed by the autophagy inhibitor 3-MA. As shown in our previous study, autophagy in the myocardium was impaired after CME. Inhibition of Egr-1 expression in vivo restored the autophagy flux and reduced myocardial apoptosis, at least partially, by inhibiting the Egr-1/Bim/Beclin-1 pathway, as evidenced by the results of the western blot, RT-qPCR, and TUNEL staining. At the same time, TEM showed a dramatic increase in the number of typical autophagic vacuoles in the Egr-1 inhibitor group compared to the CME group. Based on these findings, the Egr-1/Bim/Beclin-1 pathway may be involved in CME-induced myocardial injury by regulating myocardial autophagy and apoptosis, and this pathway represents a potential therapeutic target in CME.