Reduction Of Myocardial Infarct Size Research Articles

Effect of Cangrelor on Infarct Size in ST-Segment Elevation Myocardial Infarction Treated By Primary Percutaneous Coronary Intervention: A Randomized Controlled Trial (The PITRI Trial).

Background: The administration of intravenous cangrelor at reperfusion achieves faster onset of platelet P2Y12 inhibition than oral ticagrelor and has been shown to reduce myocardial infarct (MI) size in the pre-clinical setting. We hypothesized that the administration of cangrelor at reperfusion will reduce MI size and prevent microvascular obstruction (MVO) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Methods: This was a Phase 2, multi-center, randomized, double-blind, placebo controlled clinical trial conducted between November 2017 to November 2021 in six cardiac centers in Singapore (NCT03102723). Patients were randomized to receive either cangrelor or placeboinitiated prior to the PPCI procedure on top of oral ticagrelor. The key exclusion criteria included: presenting <6 hours of symptom onset, prior MI and stroke or transient ischemic attack; on concomitant oral anticoagulants; and a contraindication for cardiovascular magnetic resonance (CMR). The primary efficacy endpoint was acute MI size by CMR within the first week expressed as percentage of the left ventricle mass ( %LVmass). MVO was identified as areas of dark core of hypoenhancement within areas of late gadolinium enhancement. The primary safety endpoint was Bleeding Academic Research Consortium (BARC)-defined major bleeding in the first 48 hours. Continuous variables were compared by Mann-Whitney U test [reported as median (1st quartile- 3rd quartile)] and categorical variables were compared by Fisher's exact test. A 2-sided P<0.05 was considered statistically significant. Results: Of 209 recruited patients, 164 patients (78% ) completed the acute CMR scan. There were no significant differences in acute MI size [placebo: 14.9 (7.3 - 22.6) %LVmass versus cangrelor: 16.3 (9.9 - 24.4)%LVmass, P=0.40] or the incidence [placebo: 48% versus cangrelor: 47%, P=0.99] and extent of MVO [placebo:1.63 (0.60 - 4.65)%LVmass versus cangrelor: 1.18 (0.53 - 3.37)%LVmass, P=0.46] between placebo and cangrelor despite a two-fold decrease in platelet reactivity with cangrelor. There were no BARC-defined major bleeding events in either group in the first 48 hours. Conclusions: Cangrelor administered at time of PPCI did not reduce acute MI size or prevent MVO in STEMI patients given oral ticagrelor despite a significant reduction of platelet reactivity during the PCI procedure.

Japanese Traditional Herbal Medicine, Rikkunshito, Partially Suppresses Inflammatory Responses in Myocardial Ischemia/Reperfusion Injury.

Myocardial ischemia/reperfusion (I/R) injury can cause additional damage to an ischemic myocardium, even after successful reperfusion therapy. Inflammation is a mechanism that exacerbates myocardial damage after I/R injury. Rikkunshito(RKT) is a traditional Japanese herbal medicine widely used to treat gastrointestinal symptoms. It attenuates inflammation and fibrosis in some diseases of the heart; however, it remains unclear whether RKT exerts cardioprotective effects against myocardial I/R injury. To elucidate this, we evaluated the effects of RKT pre-treatment by oral administration on the myocardium in a mouse model of in vivo I/R injury. Mice were randomly assigned to a group receiving distilled water (DW) or one receiving RKT (1000 mg/kg/day) for 14 days orally. For each of the RKT and DW groups, a sham group, an I/R 2 h group, and an I/R 24 h group were created. On day 15, myocardial I/R surgery was performed. The left anterior descending coronary artery (LAD) was ligated for 30 min, and reperfusion time was set at 2 h or 24 h. The myocardial infarct size (IS) was measured after 2 h of reperfusion, and cardiac cytokine mRNA expression levels were evaluated by quantitative reverse transcription polymerase chain reaction (RT-PCR) after 2 h and 24 h of reperfusion. RKT pre-treatment significantly suppressed the cardiac mRNA expression level of interleukin-1β in the RKT-I/R 2 h group compared to the DW-I/R 2 h group (P < 0.05). Additionally, RKT significantly suppressed the mRNA expression levels of transforming growth factor-β compared to DW; the same result was obtained for the expression levels of interleukin-6. However, RKT did not reduce the IS or mRNA expression levels of the cardiac congestive markers natriuretic peptide a(NPPA) and natriuretic peptide b (NPPB). In addition, RKT did not alter the plasma concentration of ghrelin and sirtuin 1 (Sirt1), which have been reported to be stimulated by RKT. This study showed that pre-treatment of RKT for myocardial I/R injury partially suppressed inflammation-related cytokines. However, further studies are needed on the effect of RKT on the reduction of myocardial infarction size.

An inflammation resolution-promoting intervention prevents atrial fibrillation caused by left ventricular dysfunction.

Recent studies suggest that bioactive mediators called resolvins promote an active resolution of inflammation. Inflammatory signalling is involved in the development of the substrate for atrial fibrillation (AF). The aim of this study is to evaluate the effects of resolvin-D1 on atrial arrhythmogenic remodelling resulting from left ventricular (LV) dysfunction induced by myocardial infarction (MI) in rats. MI was produced by left anterior descending coronary artery ligation. Intervention groups received daily intraperitoneal resolvin-D1, beginning before MI surgery (early-RvD1) or Day 7 post-MI (late-RvD1) and continued until Day 21 post-MI. AF vulnerability was evaluated by performing an electrophysiological study. Atrial conduction was analysed by using optical mapping. Fibrosis was quantified by Masson's trichrome staining and gene expression by quantitative polymerase chain reaction and RNA sequencing. Investigators were blinded to group identity. Early-RvD1 significantly reduced MI size (17 ± 6%, vs. 39 ± 6% in vehicle-MI) and preserved LV ejection fraction; these were unaffected by late-RvD1. Transoesophageal pacing induced atrial tachyarrhythmia in 2/18 (11%) sham-operated rats, vs. 18/18 (100%) MI-only rats, in 5/18 (28%, P < 0.001 vs. MI) early-RvD1 MI rats, and in 7/12 (58%, P < 0.01) late-RvD1 MI rats. Atrial conduction velocity significantly decreased post-MI, an effect suppressed by RvD1 treatment. Both early-RvD1 and late-RvD1 limited MI-induced atrial fibrosis and prevented MI-induced increases in the atrial expression of inflammation-related and fibrosis-related biomarkers and pathways. RvD1 suppressed MI-related atrial arrhythmogenic remodelling. Early-RvD1 had MI sparing and atrial remodelling suppressant effects, whereas late-RvD1 attenuated atrial remodelling and AF promotion without ventricular protection, revealing atrial-protective actions unrelated to ventricular function changes. These results point to inflammation resolution-promoting compounds as novel cardio-protective interventions with a particular interest in attenuating AF substrate development.

Magnetic vagus nerve stimulation alleviates myocardial ischemia-reperfusion injury by the inhibition of pyroptosis through the M2AChR/OGDHL/ROS axis in rats.

Myocardial ischemia-reperfusion (I/R) injury is accompanied by an imbalance in the cardiac autonomic nervous system, characterized by over-activated sympathetic tone and reduced vagal nerve activity. In our preceding study, we pioneered the development of the magnetic vagus nerve stimulation (mVNS) system. This system showcased precise vagus nerve stimulation, demonstrating remarkable effectiveness and safety in treating myocardial infarction. However, it remains uncertain whether mVNS can mitigate myocardial I/R injury and its specific underlying mechanisms. In this study, we utilized a rat model of myocardial I/R injury to delve into the therapeutic potential of mVNS against this type of injury. Our findings revealed that mVNS treatment led to a reduction in myocardial infarct size, a decrease in ventricular fibrillation (VF) incidence and a curbing of inflammatory cytokine release. Mechanistically, mVNS demonstrated beneficial effects on myocardial I/R injury by inhibiting NLRP3-mediated pyroptosis through the M2AChR/OGDHL/ROS axis. Collectively, these outcomes highlight the promising potential of mVNS as a treatment strategy for myocardial I/R injury.

Adjunct remote ischemic conditioning to PCI in ST-segment elevation myocardial infraction patients: Systematic review and meta-analysis

Abstract Introduction ST-segment elevation myocardial infarction (STEMI) is the most dangerous presentation of the acute coronary syndrome (ACS). Throughout the last three decades, clinicians have been attempting to reduce the short and long-term major adverse cardiac events (MACE) associated with STEMI. Remote ischemic conditioning (RIC) is one of the new adjunctive modalities to PCI in treating STEMI patients whereby brief reversible episodes of ischemia and reperfusion are applied to the tissue (by alternative cycles of inflation and deflation of a blood pressure cuff on the upper or lower limb) confers global protection and renders remote tissues resistant to ischemia/reperfusion injury. This review aims to provide reliable evidence from published randomized controlled trials (RCTs) regarding whether RIC is beneficial for STEMI patients or not. Methods We followed the PRISMA guidelines during the preparation of this systematic review and meta-analysis. A computer literature search for (PubMed, Web of Science, Scopes, and Google Scholar) was carried out. We included RCT, comparing the remote ischemic conditioning, regardless of its timing of application to PCI, with either placebo or sham procedure, in terms of both short-term and long-term cardio protection. Outcomes of myocardial salvage index, myocardial infarction size, and left ventricular ejection fraction were pooled as the standardized mean difference between the two groups from baseline to endpoint. Results 11 RCTs (7151 patients), were included in this analysis. The overall effect on short-term outcomes, was in favor of PCI only in terms of myocardial salvage index(P value=0.04, 95% CI [0.00-0.08]), and left ventricular ejection fraction(P value=0.05, 95% CI [0.02,2.16]), while the adjunctive application of remote ischemic conditioning was beneficial in terms of: myocardial infarct size ( P value=0.004, 95% CI [-3.22,-0.62]). Regarding the long-term outcomes, the overall effect did not show any benefit in either of the two groups in terms of: major adverse cardiac and cerebrovascular events (MACCE) (P value=0.13, 95% CI [0.48,1.10]), hospitalization for heart failure (P value=1.00, 95% CI [0.83,1.20]), and cardiac death (P value=0.91, 95% CI [0.73,1.32]). Conclusion The adjunctive application of RIC to PCI during treatment of STEMI patients showed a beneficial effect only on short-term reduction of myocardial infarct size, nevertheless, it was not of benefit regarding the other short and long-term metrics of myocardial salvage and left ventricular function.

Abstract 14605: Association of SGLT-2 Inhibition With Size of Myocardial Infarction in Patients With Type 2 Diabetes Mellitus

Introduction: Preclinical data suggest that sodium-glucose-cotransporter-2 inhibitors (SGLT-2i) reduce the size of myocardial infarction (MI). This study aimed to assess the association of SGLT-2i use with the size of MI and clinical outcome. Methods: In a retrospective single center cohort study, patients with diagnosed diabetes mellitus type 2 who were admitted for MI and treated with PCI between November 2015 and November 2022 were analyzed and grouped according to SGLT-2i use. Following PCI, serial high sensitivity troponin T (cTn, Roche) measurements were performed according to in-house protocol. The primary outcome was the size of MI determined by the peak cTn normalized on the endangered myocardial area (EMA) calculated according to culprit lesion localization and coronary arterial dominance. Secondary outcomes were in-hospital adverse events (i.e. in-hospital death or stroke) and length of intensive care unit (ICU) treatment. The propensity score method was used to assess the association with outcomes. Results: 631 patients were identified: 85 with ongoing SGLT-2i therapy and 537 with other antidiabetic medication. Patients using SGLT-2i were younger (median age [years]: 67 [interquartile range, IQR 59-73] vs. 73 [64-79], p&lt;0.01) and had a higher eGFR at admission (75 [57-91] vs. 68 [49-88] ml/min/1.73m 2 , p=0.03). The median cTn samples per patient was 6 (5-8). There was no significant difference in the peak cTn levels between the two groups (SGLT-2i use vs. no SGLT-2i use: 53 (12-173) vs. 65 (20-174) х the upper limit of normal [ULN], p=0.26). After augmented inverse-probability weighted propensity score matching, ongoing SGLT-2i therapy was significantly associated with a reduced MI size (difference between means: -2.19 [95% confidence interval, -4.07 to -0.31] x ULN/EMA (1/%), p=0.02). SGLT-2i use was associated with less in-hospital adverse events (-4.69 [-8.70 to -0.69] %, p=0.02) and with less days on ICU (-0.27 [-0.53 to -0.01] days, p=0.045). Conclusion: In this retrospective cohort study of patients with DM presenting with MI, prior prescription of SGLT-2i was associated with reduced MI size and fewer adverse events during hospitalization. This might indicate that SGLT2i reduces the size of MI.

Abstract 15064: Programmed Death-Ligand 1 Attenuates Myocardial Injury Following Myocardial Infarction

Introduction: Myocardial infarction (MI) represents a major global cause of morbidity and mortality. Immune therapy to mitigate the secondary injury to myocardial tissues following MI is lacking. Programmed death-1 (PD-1) is an inhibitory protein expressed by immune cells during activation. Programmed death-ligand 1 (PDL1) binds to PD-1 and limits collateral damage in diseases with chronic inflammatory response. The objective of this study was to evaluate the impact of PDL1 on myocardial injury following MI. Methods: 56 C57BL/6 male and female mice underwent left anterior descending artery (LAD) ligation. Mice were randomized to receive 50 μg of PDL1 (14 intramyocardial, 14 intraperitoneal) or PBS (12 intramyocardial, 16 intraperitoneal) immediately after LAD ligation. Echocardiography was obtained at baseline and 2 weeks after MI. Mice hearts were then explanted and sectioned for Masson’s trichrome staining. An additional 25 mice after MI without treatment were terminated on postoperative day 1, 3, 5, 7, and 14. Peripheral blood and myocardium were stained for CD45, CD11b, Ly6c, and PD-1 for flow cytometry. Results: Myocardial infarct size reduction was observed after PDL1 treatment ( Fig. A-C ). Compared with controls, PDL1 delivered intramyocardially significantly improved ejection fraction from 29.8 ± 12.4 % to 41.4 ± 14.0 % (p = 0.04), and when delivered intraperitoneally, from 32.5 ± 9.4 % to 47.7 ± 8.0 % (p &lt; 0.0001, Fig. D ). In the myocardium, the percentage of monocytes that were PD-1+ surged from 0.2 ± 0.2 % on day 1 to 83.8 ± 17.7 % on day 3 and remained elevated 14 days after MI at 31.5 ± 23.6 % ( Fig. E ). Conclusions: PDL1 can attenuate myocardial injury and partially preserve cardiac function following MI in a rodent model. PD-1+ monocytes may be one of the key mediators of secondary myocardial injury after MI. Future studies will determine the mechanism of how PDL1 salvage myocardial damage to help develop a potential novel therapy.

Cardioprotective Effect of Empagliflozin and Circulating Ketone Bodies During Acute Myocardial Infarction.

SGLT2i (sodium-glucose cotransporter-2 inhibitors) improve clinical outcomes in patients with heart failure, but the mechanisms of action are not completely understood. SGLT2i increases circulating levels of ketone bodies, which has been demonstrated to enhance myocardial energetics and induce reverse ventricular remodeling. However, the role of SGLT2i or ketone bodies on myocardial ischemia reperfusion injury remains in the dark. The objective of this study is to investigate the cardioprotective potential of empagliflozin and ketone bodies during acute myocardial infarction (MI). We used a nondiabetic porcine model of ischemia reperfusion using a percutaneous occlusion of proximal left anterior descending artery for 45 minutes. Animals received 1-week pretreatment with either empagliflozin or placebo prior to MI induction. Additionally, a third group received intravenous infusion of the ketone body beta-hydroxybutyrate BOHB (beta-hydroxybutyrate) during the MI induction. Acute effects of the treatments were assessed 4-hour post-MI by cardiac magnetic resonance and histology (thioflavin for area at risk, triphenyltetrazolium chloride staining for MI size). All animals were euthanized immediately postcardiac magnetic resonance, and heart samples were collected. The area at risk was similar in all groups. Empagliflozin treatment increased BOHB levels. Empagliflozin-treated animals showed significantly higher myocardial salvage, smaller MI size (both by cardiac magnetic resonance and histology), less microvascular obstruction, and improved cardiac function (left ventricle ejection fraction and strain). Furthermore, empagliflozin-treated animals demonstrated reduced biomarkers of cardiomyocyte apoptosis and oxidative stress compared with placebo. The BOHB group showed similar results to the empagliflozin group. One-week pretreatment with empagliflozin ameliorates ischemia reperfusion injury, reduces MI size and microvascular obstruction, increases myocardial salvage, preserves left ventricle systolic function, and lowers apoptosis and oxidative stress. Periprocedural intravenous infusion of BOHB during myocardial ischemia also induces cardioprotection, suggesting a role for BOHB availability as an additional mechanism within the wide spectrum of actions of SGLT2i.

Exercise training combined with alprostadil improves myocardial infarction and coronary microcirculation disorder in aged rats by inhibiting mitogen-activated protein kinase (MAPK) signaling pathway activation.

We aimed to explore the effects and mechanisms of exercise training combined with alprostadil (ALPR) treatment on myocardial infarction (MI) in aged rats. Male Wistar rats were randomly divided into five groups. One day after MI induction, an automatic biochemical analyzer was used to measure cardiac troponin I (cTnI), cardiac troponin T (cTnT), and creatine kinase MB isoenzyme (CK-MB) serum levels. One week after MI induction, echocardiography was performed to examine the left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF), and left ventricular fraction shortening (LVFS) rates of the rats. Parameters such as body weight (BW), heart mass index, and the heart weight (HW)/tibia length (TL) ratio of the rats were also calculated. Western blot was performed to assess angiogenesis and mitogen-activated protein kinase (MAPK) signal-related protein expression. Compared with the MI group, the LVEDD and LVESD in the Trained + ALPR group were significantly decreased, while LVEF, LVFS, HW/BW, and HW/TL were significantly increased. Additionally, the Trained + ALPR group exhibited decreased levels of cTnI, cTnT, and CK-MB and significantly reduced MI size and myocardial injury. Moreover, compared with the Trained or ALPR group, the Trained + ALPR group showed upregulated energy metabolism, increased microvessel density, and better efficacy. Finally, the Trained + ALPR group showed a significant increase in angiogenesis-related proteins and a significant reduction in MAPK signaling pathway-related protein activity. Exercise training combined with ALPR improved MI in elderly rats by inhibiting MAPK signaling, promoting angiogenesis, and increasing metabolism.

Probiotic Therapy with Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis Results in Infarct Size Limitation in Rats with Obesity and Chemically Induced Colitis

In this study, we investigated the effect of three different probiotics, namely, a combination of Lactobacillus acidophilus (LA-5) and Bifidobacterium animalis subsp. lactis (BB-12), Saccharomyces boulardii, and Enterococcus faecium L3 on myocardial infarct size in rats with diet-induced obesity (DIO) and chemically-induced colitis (CIC). Potential associations between the effects of probiotics on myocardial ischemia-reperfusion injury and gut microbiome patterns as well as the serum levels of pro- and anti-inflammatory cytokines, lipopolysaccharide, and short chain fatty acids were also studied. Intragastric administration of lyophilized Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis at a dose of 1.2 × 108 CFU/mL for 15 days resulted in myocardial infarct size reduction in rats with DIO, CIC, and antibiotic-induced dysbiosis. This cardioprotective effect was associated with specific changes in cytokine concentrations, namely reduced levels of IL-1β, TNF-α, IL-2, and IL-8. At the same time, the use of Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis was accompanied by a significant reduction in lipopolysaccharide level, suggesting normalization of intestinal epithelial barrier permeability. However, the cardioprotective effect of Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis is not secondary to improved healing of the intestinal mucosa in CIC, as evidenced by the lack of difference in histopathological scores.

Mammalian Target of Rapamycin Inhibition in Patients With ST-Segment Elevation Myocardial Infarction

BackgroundEarly inflammation following acute ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (PCI) affects myocardial infarct (MI) size and left ventricular remodeling. The mammalian target of rapamycin (mTOR) is involved in the enhanced inflammatory response and its inhibition has exerted beneficial effects on MI size in preclinical models of acute MI. ObjectivesThe CLEVER-ACS (Controlled Level Everolimus in Acute Coronary Syndromes) trial evaluated the effects of targeting inflammation by mTOR inhibition in patients with STEMI undergoing PCI. MethodsCLEVER-ACS was a randomized, multicenter, international, double-blind, placebo-controlled trial. A total of 150 patients with STEMI undergoing PCI were randomly assigned to oral everolimus (days 1-3: 7.5 mg daily; days 4-5: 5.0 mg daily) or placebo for 5 days. The primary endpoint was the change in MI size. The secondary endpoint was the change in microvascular obstruction (MVO) from baseline (12 hours to 5 days after PCI) to 30 days as assessed by cardiac magnetic resonance imaging. ResultsThe changes in MI size from baseline to 30 days, the primary endpoint, were –14.2 g (95% CI: –17.4 to –11.1 g) and –12.3 g (95% CI: –16.0 to –8.7 g) in the everolimus and placebo groups (P = 0.99). Corresponding changes in MVO were –4.8 g (95% CI: –6.7 to –2.9 g) and –6.3 g (95% CI: –8.7 to –4.0 g) in the everolimus and placebo groups (P = 0.14). Adverse events did not differ between the study groups. ConclusionsAmong STEMI patients undergoing PCI, early mTOR inhibition with everolimus did not reduce MI size or MVO at 30 days. (CLEVER-ACS [Controlled Level Everolimus in Acute Coronary Syndromes; NCT01529554)

Yixin Ningshen Tablet Alleviates Comorbidity of Myocardial Infarction and Depression by Enhancing Myocardial Energy Metabolism and Increasing Availability of Monoamine Neurotransmitter.

To investigate the therapeutic effect of Yixin Ningshen Tablet (YXNS) on comorbidity of myocardial infarction (MI) and depression in rats and explore the underlying mechanism. The Sprague-Dawley rats were randomly divided into 5 groups with 7 rats in each group according to their weights, including control, model, fluoxetine (FLXT, 10 mg/kg), low-dose YXNS (LYXNS, 100 mg/kg), and high-dose YXNS (HYXNS, 300 mg/kg) groups. All rats were pretreated with corresponding drugs for 12 weeks. The rat model of MI and depression was constructed by ligation of left anterior descending coronary artery and chronic mild stress stimulation. The echocardiography, sucrose preference test, open field test, and forced swim test were performed. Myocardial infarction (MI) area and myocardial apoptosis was also detected. Serum levels of interleukin (IL)-6, IL-1β, tumor necrosis factor-α (TNF-α), 5-hydroxytryptamine (5-HT), adrenocorticotrophic hormone (ACTH), corticosterone (CORT), and norepinephrine (NE) were determined by enzyme linked immunosorbent assay. The proteins of adenosine 5'-monophosphate -activated protein kinase (AMPK), p-AMPK, peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and nuclear respiratory factor 1 (NRF1) in heart were detected by Western blot analysis. The expression levels of TNF-α, IL-6, indoleamine 2,3-dioxygenase (IDO1), kynurenine 3-monooxygenase (KMO), and kynureninase (KYNU) in hippocampus were detected by real-time quantitative polymerase chain reaction. Compared with the model group, the cardiac function of rats treated with YXNS improved significantly (P<0.01). Meanwhile, YXNS effectively reduced MI size and cardiomyocytes apoptosis of rats (P<0.01 or P<0.05), promoted AMPK phosphorylation, and increased PGC-1α protein expression (P<0.01 or P<0.05). HYXNS significantly increased locomotor activity of rats, decreased the levels of TNF-α, IL-6 and IL-1β, and increased the serum levels of 5-HT, NE, ACTH, and CORT (all P<0.05). Moreover, HYXNS decreased the mRNA expressions of IDO1, KMO and KYNU (P<0.05). YXNS can relieve MI by enhancing myocardial energy metabolism. Meanwhile, YXNS can alleviate depression by resisting inflammation and increasing availability of monoamine neurotransmitters. It may be used as a potential drug to treat comorbidity of MI and depression.

Nerolidol attenuates isoproterenol-induced acute myocardial infarction in rats.

Cardiovascular diseases have high morbidity and mortality rates, and their treatment is not effective in reducing the damage caused by myocardial infarction (MI). This study aimed to investigate whether nerolidol (NRD), a sesquiterpene alcohol, could attenuate MI in an isoproterenol-treated rat model. MI was induced by the administration of two doses of isoproterenol (ISO, 100mg/kg, i.p.) with an interval of 24h between doses.The animals were divided into four groups: control (CTR) (vehicle - NaCl 0.9% + Tween 80 0.2%), MI (ISO + vehicle), MI + NRD (50 mg/kg) and MI + NRD (100 mg/kg). An electrocardiogram was performed, and contractile parameters, cardiac enzymes, infarction size, and antioxidant parameters in the heart were measured to evaluate the effects of NRD. The ISO group showed a significant rise in ST segment, QTc, and heart rate associated with a reduction in left ventricular developed pressure (LVDP), + dP/dt, and -dP/dt. In addition, there were increases in levels of creatine kinase (CK), creatine kinase-myocardial band (CK-MB), lactate dehydrogenase (LDH), and thiobarbituric acid (TBARS); reductions in superoxide dismutase (SOD) and catalase (CAT) activities; and an increase in the infarction size. Interestingly, NRD significantly attenuated almost all the parameters of ISO-induced MI mentioned above. Our results suggest that nerolidol attenuates MI caused by ISO by a marked reduction in myocardial infarct size and suppression of oxidative stress. CK total, creatine kinase total; CK-MB, creatine kinase myocardial band; LDH, lactate dehydrogenase; SOD, superoxide dismutase; CAT, catalase. CTR (vehicle group), MI (100mg/kg of isoproterenol), ISO + NRD 50 (50mg/kg of nerolidol), and ISO + NRD 100 (100mg/kg of nerolidol).

A Recombinant Dimethylarginine Dimethylaminohydrolase-1-Based Biotherapeutics to Pharmacologically Lower Asymmetric Dimethyl Arginine, thus Improving Postischemic Cardiac Function and Cardiomyocyte Mitochondrial Activity.

High serum levels of asymmetric dimethyl arginine (ADMA) are associated with cardiovascular disease and mortality. Pharmacological agents to specifically lower ADMA and their potential impact on cardiovascular complications are not known. In this study, we aimed to investigate the effect of specific lowering of ADMA on myocardial response to ischemia-reperfusion injury (I/R) and direct effects on cardiomyocyte function. Effects of recombinant dimethylarginine dimethylaminohydrolase (rDDAH)-1 on I/R injury were determined using isolated mouse heart preparation. Respiration capacity and mitochondrial reactive oxygen species (ROS) generation were determined on mouse cardiomyocytes. Our results show that lowering ADMA by rDDAH-1 treatment resulted in improved recovery of cardiac function and reduction in myocardial infarct size in mouse heart response to I/R injury (control 22.24 ±4.60% versus rDDAH-1 15.90 ±4.23%, P < 0.01). In mouse cardiomyocytes, rDDAH-1 treatment improved ADMA-induced dysregulation of respiration capacity and decreased mitochondrial ROS. Furthermore, in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes with impaired contractility under hypoxia and high ADMA, rDDAH-1 treatment improved recovery and beating frequency (P < 0.05). rDDAH-1 treatment selectively modified I/R-induced myocardial cytokine expression, resulting in reduction in proinflammatory cytokine IL-17A (P < 0.001) and increased expression of anti-inflammatory cytokines IL-10 and IL-13 (P < 0.01). Further in vitro studies showed that IL-17A was the predominant and common cytokine modulated by ADMA-DDAH pathway in heart, cardiomyocytes, and endothelial cells. These studies show that lowering ADMA by pharmacological treatment with rDDAH-1 reduced I/R injury, improved cardiac function, and ameliorated cardiomyocyte bioenergetics and beating activity. These effects may be attributable to ADMA lowering in cardiomyocytes and preservation of cardiomyocyte mitochondrial function. SIGNIFICANCE STATEMENT: The pathological role of asymmetric dimethyl arginine (ADMA) has been demonstrated by its association with cardiovascular disease and mortality. Currently, pharmacological drugs to specifically lower ADMA are not available. The present study provides the first evidence that lowering of ADMA by recombinant recombinant dimethylarginine dimethylaminohydrolase (rDDAH)-1 improved postischemic cardiac function and cardiomyocyte bioenergetics and beating activity. Our studies suggest that lowering of ADMA by pharmacologic treatment offers opportunity to develop new therapies for the treatment of cardiovascular and renal disease.

Remote Ischaemic Conditioning in STEMI Patients in Sub-Saharan AFRICA: Rationale and Study Design for the RIC-AFRICA Trial

PurposeDespite evidence of myocardial infarct size reduction in animal studies, remote ischaemic conditioning (RIC) failed to improve clinical outcomes in the large CONDI-2/ERIC-PPCI trial. Potential reasons include that the predominantly low-risk study participants all received timely optimal reperfusion therapy by primary percutaneous coronary intervention (PPCI). Whether RIC can improve clinical outcomes in higher-risk STEMI patients in environments with poor access to early reperfusion or PPCI will be investigated in the RIC-AFRICA trial.MethodsThe RIC-AFRICA study is a sub-Saharan African multi-centre, randomized, double-blind, sham-controlled clinical trial designed to test the impact of RIC on the composite endpoint of 30-day mortality and heart failure in 1200 adult STEMI patients without access to PPCI. Randomized participants will be stratified by whether or not they receive thrombolytic therapy within 12 h or arrive outside the thrombolytic window (12–24 h). Participants will receive either RIC (four 5-min cycles of inflation [20 mmHg above systolic blood pressure] and deflation of an automated blood pressure cuff placed on the upper arm) or sham control (similar protocol but with low-pressure inflation of 20 mmHg and deflation) within 1 h of thrombolysis and applied daily for the next 2 days. STEMI patients arriving greater than 24 h after chest pain but within 72 h will be recruited to participate in a concurrently running independent observational arm.ConclusionThe RIC-AFRICA trial will determine whether RIC can reduce rates of death and heart failure in higher-risk sub-optimally reperfused STEMI patients, thereby providing a low-cost, non-invasive therapy for improving health outcomes.

Effect of remote ischaemic conditioning on infarct size and remodelling in ST-segment elevation myocardial infarction patients: the CONDI-2/ERIC-PPCI CMR substudy

The effect of limb remote ischaemic conditioning (RIC) on myocardial infarct (MI) size and left ventricular ejection fraction (LVEF) was investigated in a pre-planned cardiovascular magnetic resonance (CMR) substudy of the CONDI-2/ERIC-PPCI trial. This single-blind multi-centre trial (7 sites in UK and Denmark) included 169 ST-segment elevation myocardial infarction (STEMI) patients who were already randomised to either control (n = 89) or limb RIC (n = 80) (4 × 5 min cycles of arm cuff inflations/deflations) prior to primary percutaneous coronary intervention. CMR was performed acutely and at 6 months. The primary endpoint was MI size on the 6 month CMR scan, expressed as median and interquartile range. In 110 patients with 6-month CMR data, limb RIC did not reduce MI size [RIC: 13.0 (5.1–17.1)% of LV mass; control: 11.1 (7.0–17.8)% of LV mass, P = 0.39], or LVEF, when compared to control. In 162 patients with acute CMR data, limb RIC had no effect on acute MI size, microvascular obstruction and LVEF when compared to control. In a subgroup of anterior STEMI patients, RIC was associated with lower incidence of microvascular obstruction and higher LVEF on the acute scan when compared with control, but this was not associated with an improvement in LVEF at 6 months. In summary, in this pre-planned CMR substudy of the CONDI-2/ERIC-PPCI trial, there was no evidence that limb RIC reduced MI size or improved LVEF at 6 months by CMR, findings which are consistent with the neutral effects of limb RIC on clinical outcomes reported in the main CONDI-2/ERIC-PPCI trial.

Down-regulation of VCAM-1 in bone mesenchymal stem cells reduces inflammatory responses and apoptosis to improve cardiac function in rat with myocardial infarction

BackgroundBone mesenchymal stem cells (BMSCs) has been well known to exert therapeutic potential for patients with myocardial infarction (MI). VCAM-1 can promote the migration of lymphocytes to the inflammatory zone. In the present study, we tried to explore whether VCAM-1 silenced-BMSCs have better therapeutic effects on MI. MethodsBMSCs were isolated and cultured followed by treatment of a lentivirus silencing VCAM-1 and NF-κB activator (PMA). Besides, MI rat models were also established and injected with treated BMSCs to detect the effect of VCAM-1 silenced-BMSCs in MI, as evidenced by detection of cardiac function, survival of rats within 72 h, infarct size and myocardial cell apoptosis. Moreover, the expression of NF-κB-regulated gene products was also determined. ResultsThe implantation of sh-VCAM-1 BMSCs into MI rats resulted in more reductions in myocardial infarct size as well as myocardial cell apoptosis, improved cardiac function, the number of survived rats within 72 h, and survival time within 72 h compared with the individual treatments of either BMSCs or control. In addition, transplanted BMSCs down-regulated the expression of NF-κB-p65, MMP-9, TNF-α, and Bax, and up-regulated VEGF and Bcl-2 in myocardial tissue, which could be further enhanced by sh-VCAM-1 and rescued by PMA. ConclusionOur study demonstrated that silencing VCAM-1 in BMSCs could inhibit inflammation and apoptosis, thus improving cardiac function in MI.

The circRNA CNEACR regulates necroptosis of cardiomyocytes through Foxa2 suppression.

Circular RNAs (circRNAs) are differentially expressed in various cardiovascular disease including myocardial ischemia-reperfusion (I/R) injury. However, their functional impact on cardiomyocyte cell death, in particular, in necrotic forms of death remains elusive. In this study, we found that the level of mmu_circ_000338, a cardiac- necroptosis-associated circRNA (CNEACR), was reduced in hypoxia-reoxygenation (H/R) exposed cardiomyocytes and I/R-injured mice hearts. The enforced expression of CNEACR attenuated the necrotic form of cardiomyocyte death caused by H/R and suppressed of myocardial necrosis in I/R injured mouse heart, which was accompanied by a marked reduction of myocardial infarction size and improved cardiac function. Mechanistically, CNEACR directly binds to histone deacetylase (HDAC7) in the cytoplasm and interferes its nuclear entry. This leads to attenuation of HDAC7-dependent suppression of forkhead box protein A2 (Foxa2) transcription, which can repress receptor-interacting protein kinase 3 (Ripk3) gene by binding to its promoter region. In addition, CNEACR-mediated upregulation of FOXA2 inhibited RIPK3-dependent necrotic/necroptotic death of cardiomyocytes. Our study reveals that circRNAs such as CNEACR can regulate the cardiomyocyte necroptosis associated activity of HDACs, promotes cell survival and improves cardiac function in I/R-injured heart. Hence, the CNEACR/HDAC7/Foxa2/ RIPK3 axis could be an efficient target for alleviating myocardial damage caused by necroptotic death in ischemia heart diseases.

Diabetic Aldehyde Dehydrogenase 2 Mutant (ALDH2*2) Mice Are More Susceptible to Cardiac Ischemic-Reperfusion Injury Due to 4-Hydroxy-2-Nonenal Induced Coronary Endothelial Cell Damage.

BackgroundAldehyde dehydrogenase‐2 (ALDH2), a mitochondrial enzyme, detoxifies reactive aldehydes such as 4‐hydroxy‐2‐nonenal (4HNE). A highly prevalent E487K mutation in ALDH2 (ALDH2*2) in East Asian people with intrinsic low ALDH2 activity is implicated in diabetic complications. 4HNE‐induced cardiomyocyte dysfunction was studied in diabetic cardiac damage; however, coronary endothelial cell (CEC) injury in myocardial ischemia‐reperfusion injury (IRI) in diabetic mice has not been studied. Therefore, we hypothesize that the lack of ALDH2 activity exacerbates 4HNE‐induced CEC dysfunction which leads to cardiac damage in ALDH2*2 mutant diabetic mice subjected to myocardial IRI.Methods and ResultsThree weeks after diabetes mellitus (DM) induction, hearts were subjected to IRI either in vivo via left anterior descending artery occlusion and release or ex vivo IRI by using the Langendorff system. The cardiac performance was assessed by conscious echocardiography in mice or by inserting a balloon catheter in the left ventricle in the ex vivo model. Just 3 weeks of DM led to an increase in cardiac 4HNE protein adducts and, cardiac dysfunction, and a decrease in the number of CECs along with reduced myocardial ALDH2 activity in ALDH2*2 mutant diabetic mice compared with their wild‐type counterparts. Systemic pretreatment with Alda‐1 (10 mg/kg per day), an activator of both ALDH2 and ALDH2*2, led to a reduction in myocardial infarct size and dysfunction, and coronary perfusion pressure upon cardiac IRI by increasing CEC population and coronary arteriole opening.ConclusionsLow ALDH2 activity exacerbates 4HNE‐mediated CEC injury and thereby cardiac dysfunction in diabetic mouse hearts subjected to IRI, which can be reversed by ALDH2 activation.

Colchicine-Containing Nanoparticles Attenuates Acute Myocardial Infarction Injury by Inhibiting Inflammation.

Anti-inflammatory therapy is important for reducing myocardial injury after acute myocardial infarction (MI). New anti-inflammatory drugs and their mechanism are necessary to be explored to improve clinical efficacy. We aimed to improve the efficacy of colchicine on attenuating MI injury by nano-drug delivery systems and to investigate the mechanism of anti-inflammatory. A colchicine-containing delivery system based on calcium carbonate nanoparticles (ColCaNPs) was synthesized. The protection against MI by ColCaNPs was evaluated using an in vivo rat model established by ligating the left anterior descending coronary artery. Macrophage polarization and the levels of inflammatory cytokines were determined using immunohistochemistry, Western blot, and ELISA analysis. ColCaNP treatment showed about a 45% reduction in myocardial infarct size and attenuating myocardial fibrosis compared with groups without drug intervention after MI. Furthermore, ColCaNPs significantly decreased the levels of CRP, TNF-α, and IL-1β in serum and the expression of proinflammatory cytokine in myocardial tissues after MI (p &lt; 0.05). We also found that ColCaNPs notably restrained pyroptosis and inhibited inflammatory response by modulating on M1/M2 macrophage polarization and suppressing TLR4/NFκB/NLRP3 signal pathway. Colchicine-containing nanoparticles can protect against MI injury in a clinically relevant rat model by reducing inflammation. In addition, calcium carbonate nanoparticles can increase the cardioprotective effects of colchicine.