Cardiac rupture during acute myocardial infarction : Autopsy study (2004-2020)

INTRODUCTION

Cardiac rupture is a rare but critical complication of myocardial infarction with an incidence of 1 to 3% of cases. We aimed in this autopsy study to analyze the anatomical, epidemiological, cardiac, and coronary profiles of cardiac rupture in the Monastir region.

METHODS

We conducted a descriptive study with retrospective data collection of all cases of myocardial infarction complicated by a cardiac rupture over seventeen years (2004-2020).

RESULTS

Thirty-one cases were included in this study. The mean age of the cases was 67 years with a male predominance. Sixteen cases (57%) had cardiovascular risk factors. The most common symptomatology reported before death was acute chest pain in 57% of cases. Fourteen cases (45%) corresponded to the definition of sudden cardiac death. At autopsy, the heart had a mean weight of 452.78 grams. A large hemopericardium was associated in 90% of cases. Myocardial rupture involved the posterior wall of the left ventricle in 50% of cases. The myocardial rupture occurred at a site of acute myocardial infarction in 86% of cases and on a myocardial scar in 14% of cases. The coronary study showed double or triple vessel atherosclerotic coronary artery disease in 57% of cases with fresh thrombi at the infarct-related coronary in 11% of cases.

CONCLUSIONS

Our analysis found that cardiac rupture mostly involved elderly subjects with underlying cardiovascular risk factors. Our findings sustain that age is a determining prognostic factor after acute coronary syndrome with the need for further education and awareness-raising efforts to speed up access to care for these patients.

[The role of Cardiovascular Magnetic Resonance in Interventional Cardiology]

Cardiovascular magnetic resonance has emerged as a very helpful tool for the interventional cardiologists not only in the assessment and treatment of coronary artery disease, but also in the evaluation of various structural cardiac diseases. The main pulse sequences are standardised, acquired during short breath-holds, and include steady-state free precession cines, dynamic myocardial first-pass perfusion imaging during contrast injection, and late enhancement imaging for the identification of myocardial substrates. Less than 30-minute CMR studies are now available for the most common clinical indications. More recently, T1 and T2 parametric myocardial maps are promising for detailed myocardial tissue characterisation (edema, replacement fibrosis, diffuse interstitial fibrosis). Technical aspects will not be addressed with particular emphasis on clinical applications.

[Evaluating the performance of Tunisian regional hospitals. Study Protocol of management delays of ST elevation myocardial infarction]

RESEARCH PROBLEM

ST Elevation Myocardial Infarction (STEMI+) is an absolute emergency. The young age of patients and the difficulty of access to care remain the main characteristics of STEMI+ management in Tunisia. In the governorate of Béja, located in the Northwestern region of Tunisia, given the lack of a cardiology interventional room in the hospital and in the private establishments of the region and the distance from the specialized centers of at least 127 km, the patient is beyond 90 min of the transfer. This delay in care generates a heavy burden of morbidity and mortality. The main objective of this study will be to audit the delays of management of patients presenting STEMI+ at the regional hospital of Béja (Tunisia) in accordance with the recommendations of learned societies. Secondarily, we will identify factors associated with delayed presentation after the onset of clinical symptoms. Investigation process : it will be a descriptive, exhaustive and prospective study, including patients admitted to the emergency and/or the cardiology department of the regional hospital of Béja for STEMI+ during the study period. For each patient admitted for STEMI, the following data will be collected : sociodemographic characteristics; medical history; cardiovascular risk factors; diagnostic and therapeutic management modalities; intra-hospital evolution; survival at 01 months in relation to the current coronary episode and the estimation of the different management delays.

RESEARCH PLAN

ethical considerations will be respected, as well as the confidentiality and anonymity of the data. The study will last one year from the 1st september 2022 to 31 august 2023. The results will allow us to describe the delays of management of patients with STEMI+ in the region of Béja (Tunisia). At least 2 publications in international scientific journals are planned.

Effect of soya phosphatidylcholine and possible underlying mechanism on ischemia/reperfusion injury in isolated perfused rat heart: an experimental and computational study

This study was designed to assess the effect of soya phosphatidylcholine (SPC) against ischemia/reperfusion (I/R) injury and the possible underlying mechanism using experimental and computational studies. I/R injury was induced by global ischemia for 30 min followed by reperfusion for 120 min. The perfusion of the SPC was performed for 10 min before inducing global ischemia. In the mechanistic study, the involvement of specific cellular pathways was identified using various inhibitors such as ATP-dependent potassium channel (KATP) inhibitor (glibenclamide), protein kinase C (PKC) inhibitor (chelerythrine), non-selective nitric oxide synthase inhibitor (L-NAME), and endothelium remover (Triton X-100). The computational study of various ligands was performed on toll-like receptor 4 (TLR4) protein using AutoDock version 4.0. SPC (100 μM) significantly decreased the levels of cardiac damage markers and %infarction compared with the vehicle control (VC). Furthermore, cardiodynamics (indices of left ventricular contraction (dp/dtmax), indices of left ventricular relaxation (dp/dtmin), coronary flow, and antioxidant enzyme levels were significantly improved as compared with VC. This protective effect was attenuated by glibenclamide, chelerythrine, and Triton X-100, but it was not attenuated by L-NAME. The computational study showed a significant bonding affinity of SPC to the TLR4-MD2 complex. Thus, SPC reduced myocardial I/R injury in isolated perfused rat hearts, which might be governed by the KATP channel, PKC, endothelium response, and TLR4-MyD88 signaling pathway.

Facile synthesis of bromelain copper nanoparticles to improve the primordial therapeutic potential of copper against acute myocardial infarction in diabetic rats

Our current investigation comprises the synthesis and pharmacological impact of bromelain copper nanoparticles (BrCuNP) against diabetes mellitus (DM) and associated ischemia/reperfusion (I/R) - induced myocardial infarction. Bromelain is a proteolytic enzyme obtained from Ananas comosus L. Merr., which has blood platelet aggregation inhibiting and arterial thrombolytic potential. Moreover, copper is well-known to facilitate glucose metabolism and strengthen cardiac muscle and antioxidant activity; although, chronic or long-term exposure to high doses of copper may lead to copperiedus. To restrict these potential hazards, we synthesized herbal nano-formulation which convincingly indicated the improved primordial therapeutic potential of copper by reformulating the treatment carrier with bromelain, resulting in facile synthesis of BrCuNP. DM was induced by administration of double cycle repetitive dose of low dose streptozotocin (20 mg/kg, i.p.) in high-fat diet- fed animals. DM and associated myocardial I/R injury were estimated by increased serum levels of total cholesterol, low-density lipoprotein, very low-density lipoprotein, lactate dehydrogenase, creatine kinase myocardial band, cardiac troponin, thiobarbituric acid reactive substances, tumor necrosis factor α, interleukin 6, and reduced serum level of high-density lipoprotein and nitrite/nitrate concentration. However, treatment with BrCuNP ameliorates various serum biomarkers by approving cardioprotective potential against DM- and I/R-associated injury. Furthermore, upturn of histopathological changes were observed in cardiac tissue of BrCuNP-treated rats in comparison to disease models.

Mes ennemis, les facteurs de risque My enemies, the risk factors

We have to distinguish between non-modifiable risk factors such as age, gender, heredity, (we cannot fight against these enemies), and modifiable risk factors (avoidable) such as hypertension, smoking, diabetes, and dyslipidemia. Environmental factors, bad diet, sedentary lifestyle, and smoking are the basis of these risk factors. Cardiovascular disease due to these risk factors is clinically silent during a given period, then symptoms occur which can eventually lead to death. Nine risk factors explain the occurrence of 90 % of myocardial infarctions (MI), their correction avoid 80 % of MI. Despite the presence of several studies proving that secondary prevention reduces coronary mortality, the management of cardiovascular risk factors is not optimal.

Effect of Empagliflozin and Liraglutide on the Nucleotide-Binding and Oligomerization Domain-Like Receptor Family Pyrin Domain-Containing 3 Inflammasome in a Rodent Model of Type 2 Diabetes Mellitus

OBJECTIVES

Chronic inflammation has been identified as an important driver of cardiovascular disease in type 2 diabetes (T2D) and can lead to a higher risk of cardiovascular events and rehospitalization. Empagliflozin or liraglutide represent 2 classes of drugs with proven efficacy in the treatment of T2D to reduce macrovascular complications; however, the exact mechanism behind their cardioprotective properties remains incompletely understood. The nucleotide-binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is implicated in the progression of cardiovascular disease and linked to the progression of cardiovascular risk factors, such as T2D.

METHODS

We set out to determine whether the sodium-glucose cotransporter-2 inhibitor, empagliflozin, or the glucagon-like peptide-1 receptor antagonist, liraglutide, modified components of NLRP3 in a rodent model of T2D, which recapitulates many of the features of humans with T2D. Empagliflozin and liraglutide were used for 8 weeks in a 32-week-old rat model of T2D and compared with an age- and sex-matched control. After treatment, left ventricular tissue samples and blood plasma were obtained for immunoblotting and an interleukin-1β enzyme-linked immunossay. NLRP3, apoptosis-associated speck-like protein, pro-caspase-1 as well as the cleaved caspase-1 subunits p12 and p10 were assessed by Western blot.

RESULTS

Goto-Kakizaki rats demonstrated increased NLRP3 inflammasome activation, but neither empagliflozin nor liraglutide demonstrated any impact across the NLRP3 inflammasome pathways or interleukin-1β levels.

CONCLUSIONS

The data suggest that the cardioprotective benefits demonstrated by sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor antagonists occur independently of the NLRP3 inflammasome.

Neuromuscular electrical stimulation but not photobiomodulation therapy improves cardiovascular parameters of rats with heart failure

The aim of the present study was to analyze the effect of neuromuscular electrical stimulation (NMES) and photobiomodulation (PBMT) on the cardiovascular parameters, hemodynamic function, arterial baroreflex sensitivity (BRS), and autonomic balance (ANS) of rats with heart failure (HF). Male Wistar rats (220-290 g) were organized into five groups: Sham (n = 6), Control-HF (n = 5), NMES-HF (n = 6), PBMT-HF (n = 6), and NMES + PBMT-HF (n = 6). Myocardial infarction (MI) was induced by left coronary artery ligation. Animals were subjected to an eight-week NMES and PBMT protocol. Statistical analysis included the General Linear Model (GLM) followed by a Bonferroni post-hoc test. Rats of the NMES-HF group showed a higher MI area than the Control-HF (P = 0.003), PBMT-HF (P = 0.002), and NMES + PBMT-HF (P = 0.012) groups. NMES-HF and NMES + PBMT-HF showed higher pulmonary congestion (P = 0.004 and P = 0.02) and lower systolic pressure (P = 0.019 and P = 0.002) than the Sham group. NMES + PBMT-HF showed lower mean arterial pressure (P = 0.02) than the Sham group. Control-HF showed a higher heart rate than the NMES-HF and NMES + PBMT-HF (P = 0.017 and P = 0.013) groups. There was no difference in the BRS and ANS variables between groups. In conclusion, eight-week NMES isolated or associated with PBMT protocol reduced basal heart rate, systolic and mean arterial pressure, without influence on baroreflex sensibility and autonomic control, and no effect of PBMT was seen in rats with HF.

After the storm: an objective appraisal of the efficacy of c-kit+ cardiac progenitor cells in preclinical models of heart disease

The falsification of data related to c-kit+ cardiac progenitor cells (CPCs) by a Harvard laboratory has been a veritable tragedy. Does this fraud mean that CPCs are not beneficial in models of ischemic cardiomyopathy? At least 50 studies from 26 laboratories independent of the Harvard group have reported beneficial effects of CPCs in mice, rats, pigs, and cats. The mechanism of action remains unclear. Our group has shown that CPCs do not engraft in the diseased heart, do not differentiate into new cardiac myocytes, do not regenerate dead myocardium, and thus work via paracrine mechanisms. A casualty of the misconduct at Harvard has been the SCIPIO trial, a collaboration between the Harvard group and the group in Louisville. The retraction of the SCIPIO paper was caused exclusively by issues with data generated at Harvard, not those generated in Louisville. In the retraction notice, the Lancet editors stated: "Although we do not have any reservations about the clinical work in Louisville that used the preparations from Anversa's laboratory in good faith, the lack of reliability regarding the laboratory work at Harvard means that we are now retracting this paper". We must be careful not to dismiss all work on CPCs because of one laboratory's misconduct. An unbiased review of the literature supports the therapeutic potential of CPCs for heart failure at the preclinical level.

Butyrate improves cardiac function and sympathetic neural remodeling following myocardial infarction in rats

Increased inflammation is found in cardiac sympathetic neural remodeling with malignant ventricular arrhythmia (VA) following myocardial infarction (MI). Butyrate, as a microbiota-derived short-chain fatty acid, can inhibit inflammation and myocardial hypertrophy. However, the role of butyrate in sympathetic neural remodeling after MI is unknown. This study aimed to investigate whether butyrate could improve cardiac dysfunction and VA following MI by regulating inflammation and sympathetic neural remodeling. MI rats were randomized to administrate the butyrate or vehicle through intraperitoneal injection to undergo the study. Our data demonstrated that butyrate treatment preserved the partial cardiac function at 7 days post-MI. Butyrate downregulated the expression of essential for inflammatory response in the infarct border zone at 3 days post-MI. Particularly, butyrate promoted expression of M2 macrophage markers. Increased expressions of nerve growth factor and norephinephrine at 7 days after MI were inhibited in butyrate-treated rats. Furthermore, butyrate significantly decreased the density of nerve fibers for growth-associated protein-43 and tyrosine hydroxylase and resulted in fewer episodes of inducible VA. In conclusion, butyrate administration ameliorated cardiac function and VA after MI possibly through promoting M2 macrophage polarization to suppress inflammatory responses and inhibit sympathetic neural remodeling and may present an effective pharmacological strategy for the prevention of MI-related remodeling.

Cardioprotective effects of (E)-4-hydroxy-N'-(1-(3-oxo-3H-benzo[f]chromen-2-yl)ethylidene)benzohydrazide: a newly synthesized coumarin hydrazone against isoproterenol-induced myocardial infarction in a rat model

The current study was carried out to evaluate the effect of pretreatment and co-treatment with a newly synthesized coumarin hydrazone, (E)-4-hydroxy-N'-(1-(3-oxo-3H-benzo[f]chromen-2-yl)ethylidene)benzohydrazide (hereinafter EK6), against isoproterenol-induced myocardial infarction in rats. Changes in biochemistry, cardiac biomarkers, electrocardiography, and histopathology after treatment with EK6 or acenocoumarol (Sintrom) were studied. Animals were randomly divided into 4 groups: vehicle control (C), isoproterenol + Sintrom (ISO + Sin), isoproterenol + EK6 (ISO + EK6), and isoproterenol (ISO). Myocardial infarction was induced by subcutaneous ISO administration at a dose of 85 mg·kg^-1·day^-1 with a drug-free interval of 24 h on days 6 and 7. Treatment with ISO led to significant elevation (p < 0.05) in serum levels of cardiac injury biomarkers, namely cardiac troponin-T, lactate dehydrogenase, creatine kinase-MB, alanine aminotransferase, and aspartate aminotransferase compared with levels in the vehicle control. A change in the lipid profile was also observed as a significant increase in total cholesterol and triglycerides. Furthermore, ISO caused significant alterations in the electrocardiogram pattern, including significant ST-segment elevation, significant decreased R wave amplitude, and significant increase in heart rate (16%) as well as marked changes in the histopathology of the heart tissue. Pretreatment and co-treatment with newly synthesized coumarin hydrazone restored all ISO-induced biochemical, lipid, cardiac, and histopathological changes in rats with myocardial infarction.

N-acetyl-seryl-aspartyl-lysyl-proline treatment protects heart against excessive myocardial injury and heart failure in mice

Myocardial infarction (MI) in mice results in cardiac rupture at 4-7 days after MI, whereas cardiac fibrosis and dysfunction occur later. N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) has anti-inflammatory, anti-fibrotic, and pro-angiogenic properties. We hypothesized that Ac-SDKP reduces cardiac rupture and adverse cardiac remodeling, and improves function by promoting angiogenesis and inhibiting detrimental reactive fibrosis and inflammation after MI. C57BL/6J mice were subjected to MI and treated with Ac-SDKP (1.6 mg/kg per day) for 1 or 5 weeks. We analyzed (1) intercellular adhesion molecule-1 (ICAM-1) expression; (2) inflammatory cell infiltration and angiogenesis; (3) gelatinolytic activity; (4) incidence of cardiac rupture; (5) p53, the endoplasmic reticulum stress marker CCAAT/enhancer binding protein homology protein (CHOP), and cardiomyocyte apoptosis; (6) sarcoplasmic reticulum Ca2+ ATPase (SERCA2) expression; (7) interstitial collagen fraction and capillary density; and (8) cardiac remodeling and function. Acutely, Ac-SDKP reduced cardiac rupture, decreased ICAM-1 expression and the number of infiltrating macrophages, decreased gelatinolytic activity, p53 expression, and myocyte apoptosis, but increased capillary density in the infarction border. Chronically, Ac-SDKP improved cardiac structures and function, reduced CHOP expression and interstitial collagen fraction, and preserved myocardium SERCA2 expression. Thus, Ac-SDKP decreased cardiac rupture, ameliorated adverse cardiac remodeling, and improved cardiac function after MI, likely through preserved SERCA2 expression and inhibition of endoplasmic reticulum stress.

Sitagliptin protects diabetic rats with acute myocardial infarction through induction of angiogenesis: role of IGF-1 and VEGF

Angiogenesis is regulated in a tissue-specific manner in all patients, especially those with diabetes. In this study, we describe a novel molecular pathway of angiogenesis regulation in diabetic rats with myocardial infarction (MI) and examine the cardioprotective effects of different doses of sitagliptin. Male rats were divided into 5 groups: normal vehicle group, diabetic group, diabetic + MI, diabetic + MI + 5 mg/kg sitagliptin, and diabetic + MI + 10 mg/kg sitagliptin. Isoproterenol in diabetic rats resulted in significant (p < 0.05) disturbance to the electrocardiogram, cardiac histopathological manifestations, and an increase in inflammatory markers compared with the vehicle and diabetic groups. Treatment with sitagliptin improved the electrocardiogram and histopathological sections, upregulated vascular endothelial growth factor (VEGF) and transmembrane phosphoglycoprotein protein (CD34) in cardiac tissues, and increased serum insulin-like growth factor 1 (IGF-1) and decreased cardiac tissue homogenate for interleukin 6 (IL-6) and cyclooxygenase 2 (COX-2). A relationship was found between serum IGF-1 and cardiac VEGF and CD34 accompanied by an improvement in cardiac function of diabetic rats with MI. Therefore, the observed effects of sitagliptin occurred at least partly through an improvement in angiogenesis and the mitigation of inflammation. Consequently, these data suggest that sitagliptin may contribute, in a dose-dependent manner, to protection against acute MI in diabetic individuals.

Serum irisin level in myocardial infarction patients with or without heart failure

This study aimed to assess serum irisin level in myocardial infarction (MI) with or without heart failure (HF) and the possible relation between irisin and cardiac markers, tumor necrosis factor-α (TNF-α) and lipid profile. Eighty-six subjects were included (33 patients had MI, 33 patients had MI with HF, and 20 controls). Body mass index (BMI), waist/hip ratio (WHR), systolic and diastolic blood pressure (SBP and DBP), heart rate, and left ventricular ejection fraction (LVEF) were measured. Blood samples were withdrawn on admission for measuring irisin, cardiac markers, TNF-α, total cholesterol (TC), triglycerides (TGs), low-density lipoprotein-cholesterol concentration (LDL-C), and high-density lipoprotein-cholesterol concentration (HDL-C). Patients with MI and HF had reduced serum irisin, LVEF, and HDL-C and higher levels of BMI, WHR, SBP, DBP, troponin-I, creatine kinase-MB (CK-MB), TNF-α, TC, TGs, and LDL-C compared with control. Negative correlations were observed between irisin and BMI, WHR, SBP, DBP, troponin-I, CK-MB, TNF-α, TC, TGs, and LDL-C. However, positive association was noticed between irisin and LVEF and HDL-C. Irisin might be a useful biomarker in diagnosis of MI with or without HF. It could have anti-inflammatory and hypolipidemic effects. Further studies are needed to elucidate the role of irisin as a promising prophylactic or therapeutic agent in cardiovascular diseases.

Polyethylene-glycol-coated gold nanoparticles improve cardiac function after myocardial infarction in mice

Gold nanoparticles (AuNPs) are widely used for drug delivery because of their unique biological properties, such as their safety and ability to prolong drug action. Some studies have demonstrated that AuNPs accumulate in the heart, especially during pathological processes. Therefore, it is very important to understand the effect of AuNPs on the heart. Myocardial infarction (MI) is a major cause of morbidity and mortality; however, the effect of AuNPs on MI remains unclear. In the present study, we carried out a comprehensive evaluation of AuNPs on acute MI. The results showed that AuNPs accumulated in infarcted hearts, decreased infarction size, improved systolic function, and inhibited cardiac fibrosis and TNF-α accumulation. Our work indicated that AuNPs have cardioprotective effects and can be used in drug delivery systems for the treatment of cardiac diseases.

A high omega-3 fatty acid diet rapidly changes the lipid composition of cardiac tissue and results in cardioprotection

The present study was designed to ascertain the effects of 3 diets with different omega-3/6 fatty acid ratios on infarct size and the modifications that these diets induce in the lipid composition of cardiac tissue. Sprague-Dawley rats were fed omega-3/6 fatty acid diets with 1:1, 1:5, or 1:20 ratios for at least 10 days, followed by occlusion of the left anterior descending artery for 40 min and 24 h of reperfusion. Infarct size was significantly smaller in the 1:1 group than in the other groups. Significantly higher concentrations of the omega-3 fatty acids eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid were found in the 1:1 group than in the other groups. Omega-6 polyunsaturated fatty acid levels were similar between groups, although they were higher in the 1:5 and 1:20 groups than in the 1:1 group. Margaric acid concentrations were higher in the 1:1 group than in the other groups. Docosahexaenoic acid levels in cardiac tissue and infarct size were significantly correlated with no other significant links being apparent. The present study indicated that a 1:1 omega-3/6 fatty acid ratio protected against ischemia and was associated with increased omega-3 fatty acid composition of cardiac tissue.

[Emergency treatment of myocardial infarction in women]

Acute myocardial infarction (MI) affects mainly men. In women, chest pain is less typical, delaying the diagnosis and increasing the time before treatment is delivered. Morbidity-mortality is greater notably due to a modification of the myocardial reperfusion strategy. The acute care of MI is almost identical for men and women. Knowing more about the epidemiology of women with MI enables prevention strategies to be targeted.

Specific plasma oxylipins increase the odds of cardiovascular and cerebrovascular events in patients with peripheral artery disease

Oxylipins and fatty acids may be novel therapeutic targets for cardiovascular disease. The objective was to determine if plasma oxylipins or fatty acids can influence the odds of cardiovascular/cerebrovascular events. In 98 patients (25 female, 73 male) with peripheral artery disease, the prevalence of transient ischemic attacks, cerebrovascular accidents, stable angina, and acute coronary syndrome was n = 16, 10, 16, and 24, respectively. Risk factors such as being male, diagnosed hypertension, diabetes mellitus, and hyperlipidemia were not associated with events. Plasma fatty acids and oxylipins were analyzed with gas chromatography and HPLC-MS/MS, respectively. None of 24 fatty acids quantified were associated with events. In contrast, 39 plasma oxylipins were quantified, and 8 were significantly associated with events. These 8 oxylipins are known regulators of vascular tone. For example, every 1 unit increase in Thromboxane B₂/Prostaglandin F_1α and every 1 nmol/L increase in plasma 16-hydroxyeicosatetraenoic acid, thromboxane B2, or 11,12-dihydroxyeicosatrienoic acid (DiHETrE) increased the odds of having had ≥2 events versus no event (p < 0.05). The greatest predictor was plasma 8,9-DiHETrE, which increased the odds of acute coronary syndrome by 92-fold. In conclusion, specific oxylipins were highly associated with clinical events and may represent specific biomarkers and (or) therapeutic targets of cardiovascular disease.

Noninvasive approach to mend the broken heart: Is "remote conditioning" a promising strategy for application in humans?

Currently, there are no satisfactory interventions to protect the heart against the detrimental effects of ischemia-reperfusion injury. Although ischemic preconditioning (PC) is the most powerful form of intrinsic cardioprotection, its application in humans is limited to planned interventions, due to its short duration and technical requirements. However, many organs/tissues are capable of producing "remote" PC (RPC) when subjected to brief bouts of ischemia-reperfusion. RPC was first described in the heart where brief ischemia in one territory led to protection in other area. Later on, RPC started to be used in patients with acute myocardial infarction, albeit with ambiguous results. It is hypothesized that the connection between the signal triggered in remote organ and protection induced in the heart can be mediated by humoral and neural pathways, as well as via systemic response to short sublethal ischemia. However, although RPC has a potentially important clinical role, our understanding of the mechanistic pathways linking the local stimulus to the remote organ remains incomplete. Nevertheless, RPC appears as a cost-effective and easily performed intervention. Elucidation of protective mechanisms activated in the remote organ may have therapeutic and diagnostic implications in the management of myocardial ischemia and lead to development of pharmacological RPC mimetics.

Carotid versus coronary atherosclerosis burdens in acute compared with chronic symptomatic coronary artery disease

Prediction of coronary events remains elusive. Carotid atherosclerosis may be a surrogate for coronary risk, as carotid and coronary diseases occur simultaneously - albeit at times with a weak association - depending on clinical presentation. We investigated carotid and coronary atherosclerosis in men with new-onset unstable coronary artery disease (CAD) presenting with acute ST-segment elevation myocardial infarction (STEMI) vs. long-standing severe chronic stable angina (CSA). Bilateral carotid artery and 3-vessel coronary artery atherosclerosis burdens were measured within 1 month, respectively, by 3D-volumetric carotid magnetic resonance imaging and coronary angiography-derived modified CASS-50 score. Men with STEMI (n = 50) and long-standing CSA (n = 50), matched for age, were enrolled (58.6 ± 8.8 years). All of them had carotid atherosclerosis. Atherosclerosis burden was greater in the carotid arteries of STEMI vs. CSA (wall volume: 196.2 ± 44.4 vs. 169.2 ± 38.0 mm³/4 mm, p = 0.002), but greater in the coronary arteries of CSA vs. STEMI (modified CASS-50 score: 3 vs. 1, p < 0.0001). Normalized wall index (NWI) of internal carotid was associated with modified CASS-50 score in STEMI (ρ = 0.40, p = 0.022) and in CSA (ρ = -0.39, p = 0.031). Carotid atherosclerosis was observed in all CAD patients, and atherosclerosis burden in carotid and in coronary arteries varied according to clinical presentation.

Simulated microgravity increases myocardial susceptibility to ischemia-reperfusion injury via a deficiency of AMP-activated protein kinase

Gravitation is an important factor in maintaining cardiac contractility. Our study investigated whether simulated microgravity increases myocardial susceptibility to ischemia-reperfusion (IR) injury. Using the Langendorff-perfused heart model with 300 beats/min pacing, 4-week tail suspension (SUS) and control (CON) male Sprague-Dawley rats (n = 10 rats/group) were subjected to 60 min of left anterior descending coronary artery (LAD) occlusion followed by 120 min of reperfusion. Left ventricular end-systolic pressure (LVESP), left ventricular end-diastolic pressure (LVEDP), creatine kinase (CK) and lactate dehydrogenase (LDH) activity, and infarct size were assessed. Data demonstrated that there were significantly increased LVEDP, CK, LDH, and infarct size in SUS compared with CON (P < 0.05), accompanied by decreased LVESP (P < 0.05). Furthermore, TUNEL-positive cardiomyocytes were higher in SUS than that in CON (P < 0.01), and AMP-activated protein kinase (AMPK) phosphorylation and Bcl-2/Bax in SUS were less compared with CON (P < 0.05). Similarly, isolated hearts pre-treated with A-769662 exhibited better recovery of cardiac function, increased AMPK phosphorylation, and reduced necrosis and apoptosis. Furthermore, AMPKα protein showed a significant suppression in 4-week hindlimb unweighting rats. These results suggest that AMPK deficiency increases myocardial susceptibility to IR injury in rats subjected to simulated microgravity.

Peroxisome proliferator-activated receptors (PPAR) downregulate the expression of pro-inflammatory molecules in an experimental model of myocardial infarction

Myocardial infarction (MI) has been associated with an inflammatory response and a rise in TNF-α, interleukin (IL)-1β, and IL-6. Peroxisome proliferator-activated receptors (PPARs) promote a decreased expression of inflammatory molecules. We aimed to study whether PPAR stimulation by clofibrate decreases inflammation and reduces infarct size in rats with MI. Male Wistar rats were randomized into 3 groups: control, MI + vehicle, and MI + clofibrate (100 mg/kg). Treatment was administered for 3 consecutive days, previous to 2 h of MI. MI induced an increase in protein expression, mRNA content, and enzymatic activity of inducible nitric oxide synthase (iNOS). Additionally, MI incited an increased expression of matrix metalloproteinase (MMP)-2 and MMP-9, intercellular adhesion molecule (ICAM)-1, and IL-6. MI also elevated the nuclear content of nuclear factor-κB (NF-κB) and decreased IκB, both in myocyte nuclei and cytosol. Clofibrate treatment prevented MI-induced changes in iNOS, MMP-2 and MMP-9, ICAM-1, IL-6, NF-κB, and IκB. Infarct size was smaller in clofibrate-treated rats compared to MI-vehicle animals. In silico analysis exhibited 3 motifs shared by genes from renin-angiotensin system, PPARα, iNOS, MMP-2 and MMP-9, ICAM-1, and VCAM-1, suggesting a cross regulation. In conclusion, PPARα-stimulation prevents overexpression of pro-inflammatory molecules and preserves viability in an experimental model of acute MI.

[Follow-up care of patients after heart attack]

Survivors of a myocardial infarction are at increased risk for future cardiac events, including recurrent infarction, heart failure, arrhythmia, stroke, and sudden cardiac death. The primary care physician needs to be aware of the potential risks and complications facing these patients. Secondary preventive measures after myocardial infarction include an optimal medical therapy (dual antiplatelet therapy, Statin, ACE-inhibitor, and in most cases a beta-blocker) and life style modifications (quit smoking, regular physical activity, Mediterranean-style diet). Patients should be informed about how to recognize and react to cardiac symptoms.

Cardioprotective effect of pioglitazone in diabetic and non-diabetic rats subjected to acute myocardial infarction involves suppression of AGE-RAGE axis and inhibition of apoptosis

Insulin resistance increases risk of cardiovascular diseases. This work investigated the protective effect of pioglitazone on myocardial infarction (MI) in non-diabetic and diabetic rats, focusing on its role on advanced glycated endproducts (AGEs) and cardiac apoptotic machinery. Male rats were divided into 2 experiments: experiment I and II (non-diabetic and diabetic rats) were assigned as saline, MI (isoproterenol, 85 mg/kg, daily), and MI+pioglitazone (5, 10, and 20 mg/kg). Injection of isoproterenol in diabetic rats produced greater ECG disturbances compared to non-diabetic rats. Treatment with pioglitazone (5 mg/kg) reduced the infarct size and improved some ECG findings. Pioglitazone (10 mg/kg) enhanced ECG findings, improved the histopathological picture and downregulated apoptosis in cardiac tissues. Whereas the higher dose of pioglitazone (20 mg/kg) did not improve most of the measured parameters but rather worsened some of them, such as proapoptotic markers. Importantly, a positive correlation was found between serum AGEs and cardiac AGE receptors (RAGEs) versus caspase 3 expression in the two experiments. Therefore, the current effect of pioglitazone was, at least in part, mediated through downregulation of AGE-RAGE axis and inhibition of apoptosis. Consequently, these data suggest that pioglitazone, at optimized doses, may have utility in protection from acute MI.

Preserved recovery of cardiac function following ischemia-reperfusion in mice lacking SIRT3

Lack of the mitochondrial deacetylase sirtuin 3 (SIRT3) impairs mitochondrial function and increases the susceptibility to induction of the mitochondrial permeability transition pore. Because these alterations contribute to myocardial ischemia-reperfusion (IR) injury, we hypothesized that SIRT3 deficiency may increase cardiac injury following myocardial IR. Hearts of 10-week-old mice were perfused in the isolated working mode and subjected to 17.5 min of global no-flow ischemia, followed by 30 min of reperfusion. Measurements before ischemia revealed a decrease in cardiac power (-20%) and rate pressure product (-15%) in SIRT3(-/-) mice. Mitochondrial state 3 respiration (-15%), ATP synthesis (-39%), and ATP/O ratios (-29%) were decreased in hearts of SIRT3(-/-) mice. However, percent recovery of cardiac power (WT 94% ± 9%; SIRT3(-/-) 89% ± 9%) and rate pressure product (WT 89% ± 16%; SIRT3(-/-) 96% ± 3%) following IR was similar in both groups. Myocardial infarct size was not increased in SIRT3(-/-) mice following permanent ligation of the left anterior descending coronary artery (LAD). Left ventricular pressure and dP/dtmax, and mitochondrial respiration and ATP synthesis were not different between groups following LAD ligation. Thus, despite pre-existing defects in cardiac function and mitochondrial respiratory capacity in SIRT3(-/-) mice, SIRT3 deficiency does not additionally impair cardiac function following IR or following myocardial infarction.

Osteopontin is proteolytically processed by matrix metalloproteinase 9

Osteopontin is robustly upregulated following myocardial infarction (MI), which suggests that it has an important role in post-MI remodeling of the left ventricle (LV). Osteopontin deletion results in increased LV dilation and worsened cardiac function. Thus, osteopontin exerts protective effects post-MI, but the mechanisms have yet to be defined. Matrix metalloproteinases (MMPs) regulate LV remodeling post-MI, and osteopontin is a known substrate for MMP-2, -3, -7, and -9, although the cleavage sites have not been mapped. Osteopontin-derived peptides can exert distinct biological functions that may depend on their cleavage sites. We mapped the MMP-9 cleavage sites via LC-MS/MS analysis using label-free and N-terminal labeling methods, and compared them with those of MMP-2, -3, and -7. Each MMP yielded a unique cleavage profile with few overlapping cleavage sites. Using synthetic peptides, we validated 3 sites for MMP-9 cleavage at amino acid positions 151-152, 193-194, and 195-196. Four peptides were synthesized based on the upstream- and downstream-generated fragments and were tested for biological activity in isolated cardiac fibroblasts. Two peptides increased cardiac fibroblast migration rates post-wounding (p < 0.05 compared with the negative control). Our study highlights the importance of osteopontin processing, and confirms that different cleavage sites generate osteopontin peptides with distinct biological functions.

Novel high-sensitivity troponin assay requires higher cut-off value to separate acute myocardial infarction from non-acute myocardial infarction in a high-risk population

PURPOSE

The novel high-sensitivity troponin T assay (hs-cTnT) has been validated for diagnosing AMI in the emergency room. However its utility in high-risk in-patient populations is unknown.

METHODS

We retrospectively reviewed admissions to a general cardiology unit that had 2 hs-cTnT measurements in the first 12 h of presentation. We assessed 8 diagnostic algorithms that used hs-cTnT concentration and changes in concentration (including the 99th percentile cut-off of 14 ng/L) for their diagnostic utility in separating AMI patients from cardiac/nonACS and non-cardiac chest-pain patients. UA was excluded.

RESULTS

There were 233 patients (mean age 67 years, 153 were males (66%)) admitted over a 2 month period, with AMI diagnosed in 118 of these patients (51%). The recommended 99th percentile cut-off had modest accuracy (65%), good sensitivity (88%), and poor specificity (25%); a higher cut-off of 75 ng/L had a better diagnostic accuracy of 73%, p < 0.05. While some hs-cTnT algorithms were either highly sensitive or specific, none were both.

CONCLUSION

In high-risk cardiology in-patients, no hs-cTnT concentration cut-off or change more accurately diagnosed and excluded AMI, although higher cut-offs had better diagnostic utility.

[A psychocardiology update on depression and coronary heart disease]

The prevalence of a major depressive disorder in patients after myocardial infarction is 20%. Depression is a risk factor for incident coronary heart disease and poor prognosis after myocardial infarction. Poor lifestyle habits and adherence to cardiac therapy as well as metabolic and pathophysiologic changes may partially explain this link. The threatening experience of an acute coronary event and immune and inflammatory changes may be unique features contributing to incident depression after myocardial infarction. While psychotherapy, antidepressants, and physical exercise may alleviate depressive symptoms in patients with coronary heart disease, cardiac rehabilitation additionally reduces mortality risk. Attempts are being undertaken to identify the cardiotoxic characteristics of depression to develop even more effective therapies in the future.

[Kinetics of cTnI and threshold values for the diagnosis of myocardial infarction after cardiac surgery with cardiopulmonary bypass]

Introduction

Méthodes

Résultats

Conclusion

[Myocardial infarction in the young adult--retrospective analysis of cases compile at the University Hospital of Dakar]

Abstract

Les données relatives à l’infarctus du myocarde chez le jeune adulte sont rares en Afrique noir. Nous rapportons une série rétrospective de 14 cas dninfarctus du myocarde chez l’adulte jeune noir africain. Pour analyser les caractéristiques épidémiologiques, cliniques, électriques, échographiques, biologiques, thérapeutiques et évolutives de l’infarctus aigu du myocarde chez le jeune adulte nous avons étudié de manière rétrospective les dossiers médicaux d’une série consécutive des patients admis entre Janvier 2003 et Décembre 2008 pour prise en charge d’infarctus aigu du myocarde. Quatre-vingt quatre (84) cas d’infarctus du myocarde ont été pris en charge durant la période d’étude ,14 patients (16,6%) avaient un âge inférieur ou égal à 40 ans. L’âge moyen était de 34 +ou-5ans (extrêmes 27ans et 40 ans). Les facteurs de risque cardiovasculaire étaient dominés par le sexe masculin (n=11), la dyslipidémie (n=7) et le tabagisme par cigarette (n=6). La contraception orale était absente chez le 1/3 des patients. Le délai moyen d’admission était tardif (15 plus ou moins 4 heures). L’IDM était antérieur dans la moitié des cas. L’acide acétylsalicylique, les inhibiteurs de l’enzyme de conversion Les bétabloquants et les statines étaient les médicaments les plus prescrits. La thrombolyse et l’angioplastie étaient respectivement réalisées chez 3 patients et 0 patient. 4 cas d’insuffisance cardiaque, 2 cas de bloc atrioventriculaire complet et 1 cas de décès étaient les principales complications. L’infarctus du myocarde concerne également le sujet jeune noir africain. Les facteurs de risque sont essentiellement représentés par le sexe, la dyslipidémie, le tabagisme et la contraception orale.