Cardiac Remodeling Post-myocardial Infarction Research Articles

SIRT1-dependent regulation of mitochondrial metabolism participates in miR-30a-5p-mediated cardiac remodeling post-myocardial infarction

SIRT1-dependent regulation of mitochondrial metabolism participates in miR-30a-5p-mediated cardiac remodeling post-myocardial infarction

Complement factor D deficiency ameliorates adverse cardiac remodelling by inhibiting C5a-C5aR mediated ISGs+ neutrophil activation post myocardial infarction

Abstract Background Exaggerated inflammatory response after myocardial infarction (MI) exacerbates myocardial injury and adverse cardiac remodeling, leading to heart failure. Current management of MI involves myocardial protection and antifibrotic therapy but do not target the inflammatory response per se. Complement factor D (CFD) is an upstream rate-limiting enzyme of complement system activation, which is the early event of inflammatory response post MI. We hypothesize that CFD can be an important modulator of the inflammation-remodeling cascade post MI, but the specific mechanism remains elusive. Purpose To investigate the role and mechanism of CFD in regulating inflammatory expansion and adverse remodeling post MI. Methods We generated Cfd-AKO (Cfdfl/fl Adipoq-cre) mice using the Cre-LoxP recombination system, as CFD is mainly secreted by adipocytes. Immune status and cardiac remodeling progress were assessed by cardiovascular magnetic resonance (CMR), histology, flow cytometry, immunofluorescence, and ELISA. Single cell RNA sequencing (scRNA-seq) analyzed non­cardiomyocytes isolated from Cfd-AKO and WT mice post MI or sham operation. Genetic ablation and co-culture experiments dissected the functional molecular properties and intercellular communication. An CFD inhibitor ACH-4471 was used to explore the role of CFD in ischemia-reperfusion (IR) injury. Results The survival of Cfd-AKO mice was strongly improved, while ventricular arrhythmia induction rates and number of episodes were significantly reduced compared with those of WT mice. CMR imaging showed that Cfd-AKO mice had higher ejection fraction and reduced left ventricular dilation than WTs. Masson trichrome and picrosirius red staining revealed that besides smaller infarct size, the extent of fibrosis in the border and distal remote area decreased in Cfd-AKO mice. Cfd loss reduced myocardial injury, inhibited the release of inflammatory factors, and limits the amplification of complement components C3a and C5a post MI. ScRNA-seq revealed that CFD modulated neutrophil chemotactic ability and pro-inflammatory function by inducing interferon-stimulated genes expressing (ISG+) neutrophil CXCL10 expression. Mechanistically, CFD activates the ISG transcriptional profile via the C5a/C5aR dependent STAT1/2-IRF9 pathway. Activated neutrophils promote myofibroblast transformation through IL1β/IL1R dependent intercellular communication, thus facilitating pathological fibrosis. Early pharmacological blocking of CFD in mice IR injury models inhibited inflammation, reduced infarct size and ameliorated cardiac dysfunction. Conclusions We demonstrate the crucial role of CFD in cardiac remodeling post MI. This process is critically regulated by C5a-C5aR, an important component of complement-inflammation cascade. This CFD-C5a mediated neutrophil pro-inflammatory and pro-fibrotic dual activity represents a novel pathway and an attractive therapeutic window for heart failure post MI.CFD in cardiac remodelling post MI

KIAA1199/CEMIP knockdown attenuates cardiac remodeling post myocardial infarction by activating TSP4 pathway in mice

BackgroundExcessive activation of cardiac fibroblasts (CFs) significantly contributes to adverse cardiac remodeling post-myocardial infarction (MI). CEMIP, initially recognized as an enzyme involved in hyaluronic acid (HA) degradation, has also been implicated in the activation of pulmonary fibroblasts. Nevertheless, the role and mechanism of CEMIP in adverse cardiac remodeling following MI remain largely unexplored. Materials and methodsRNA sequencing (RNA-seq) was performed on cardiac tissue harvested from the infarct/peri-infarct region of mice 28 days post-MI. RNA-seq was conducted on primary cardiac fibroblasts (CFs) transfected with adenovirus overexpressing CEMIP. Adeno-associated virus serotype 9 (AAV9) was engineered for in vivo CEMIP knockdown to elucidate its impact on cardiac remodeling. Immunoprecipitation coupled with mass spectrometry (IP-MS) and co-immunoprecipitation (co-IP) were employed to elucidate the mechanism by which CEMIP affected cardiac remodeling. Key findingsRNA-seq of fibrotic heart tissue at day 28 post-MI revealed a significant upregulation of CEMIP. In vitro, CEMIP facilitated the activation of cardiac fibroblasts. In vivo, knockdown of CEMIP markedly reduced cardiac fibrosis and improved cardiac function post-MI. IP-MS and co-immunoprecipitation (co-IP) confirmed that CEMIP interacted with TSP4 through the G8 domain. Further experiments confirmed that CEMIP promoted TSP4 degradation in lysosomes in an ACTN4-dependent manner, thereby activating the FAK signaling pathway. SignificanceOur findings suggest that CEMIP significantly contributes to cardiac remodeling post-MI, which might be a novel approach for treating cardiac fibrosis following MI.

Delivery of liquid metal particles and tanshinone IIA into the pericardial cavity for myocardial infarction treatment.

Owing to their inherent flexibility and excellent biocompatibility, liquid metals (LMs) have been explored at the frontiers of clinical therapy. Herein, a LM and tanshinone IIA (TA) drugs were dispersed into sodium alginate (SA) solution by ultrasonication to prepare SA/LM/TA, which is an injectable biomaterial for stable drug release and intrapericardial injection for the treatment of myocardial infarction (MI). The SA/LM/TA has a low viscosity and can be injected smoothly using a syringe. In rat models of MI, we demonstrated that SA/LM/TA injection in the pericardial cavity is a biosafe and effective method to deliver a carrier containing LM particles and TA drugs for MI treatment. After injection, the drug release is slow and stable in the pericardial cavity, increasing the cardiac retention of drugs. After surgery and treatment for 7 days, the cardiac function of rats improved compared with the control group and the TA direct injection group. The intrapericardial injection of SA/LM/TA improves cardiac functions and mitigates cardiac remodeling post myocardial infarction of rats. Overall, the present study establishes a therapeutic strategy for treatment of myocardial infarction by intrapericardial injection of SA/LM/TA and expands the application categories of LM biomaterials in disease treatments.

Enhancing autophagic flux via FYCO1 confers protection against adverse cardiac remodeling in response to myocardial ischemia

Abstract Background Dysregulation of autophagy is known to have detrimental effects on cardiac function. Yet, the autophagy-lysosome pathway in the context of ischemia is still widely unexplored. Fyco1 is highly expressed in the heart and facilitates transport of autophagosomes in cardiomyocytes, thereby enhancing global autophagic flux. Purpose The purpose of our study was to study the potentially beneficial effects of activation of autophagy via FYCO1 on cardiac remodeling post myocardial infarction. Methods FYCO1-Tg mice were crossbred with RFP-EGFP-LC3-Tg reporter mice (FYCO1-TGxRGFP) to enable analysis of autophagic flux in vivo using confocal microscopy. Myocardial ischemia was induced by permanent ligation of left anterior descending artery (LAD). Mice were analyzed 3 and 30 days post LAD ligation. Cardiac function (ejection fraction, EF) was measured by echocardiography. Fibrosis and Infarct size (%) were assessed in Masson’s Trichrome staining. Autophagy activity was analysed by Western blot for p62 and LC3 II. Furthermore, Evans blue/TTC staining was performed to assess the area at risk and to define perfused, ischemic and necrotic area post LAD ligation. Results Under conditions of FYCO1 overexpression isolated cardiomyocytes were capable to remain a status of activated autophagy in hypoxia; presented with significantly increased protein levels of p62 (ctrl: 1±0,02; OE: 3,1±0,4) and LC3 II (ctrl: 1±0,05; OE: 5,5±0,4). In FYCO1-TGxRGFP mice we observed an overall increased autophagic flux demonstrated by significantly increased p62 expression (WT LAD: 2,9±0,4; TG LAD:4,0±0,5) and LC3 II protein levels (WT LAD: 1,6±0,2; TG LAD:14,0±1,4) post LAD ligation. While WT mice revealed accumulation of autolysosomes 30 days post LAD ligation as assessed by confocal microscopy (WT autophagosomes: 1±0,4; WT autolysosomes: 38,6±3,8), in FYCO1-TGxRGFP mice the ratio between autophagosomes and autolysosomes remained even (TG autophagosomes:43,3±5,1; TG autolysosomes: 73,5±12,4), suggesting preservation of adequate autophagic flux. In Evans blue/TTC staining, FYCO1-TGxRGFP mice demonstrated comparable ischemic but a markedly decreased necrotic area (ischemic: 1,9±1,8%; necrotic: 37,1±11,5%) of the LV as compared to WT (ischemic: 2,1±1,9%; necrotic: 53,4±31,4%). Fibrosis (WT: 19,6±1,8%; TG: 10,6±1,6%) and infarct size (WT: 34,5 ±3,9%; TG: 5,5±2%) was found significantly decreased in FYCO1-TGxRGFP-mice. Importantly, global heart function of FYCO1-TGxRGFP-mice was significantly improved post LAD compared to WT (EF WT: 36,7±6,3%; TG: 46,3±18,3%). Conclusion Our study demonstrates that activation of autophagy via FYCO1 protects against accumulation of autolysosomes and therefore protects against adverse cardiac remodeling and improves cardiac function post myocardial ischemia. These findings may offer translational potential in enhancing autophagic flux in the context of myocardial ischemia.

NKRF in Cardiac Fibroblasts Protects against Cardiac Remodeling Post-Myocardial Infarction via Human Antigen R.

Myocardial infarction (MI) remains the leading cause of death worldwide. Cardiac fibroblasts (CFs) are abundant in the heart and are responsible for cardiac repair post-MI. NF-κB-repressing factor (NKRF) plays a significant role in the transcriptional inhibition of various specific genes. However, the NKRF action mechanism in CFs remains unclear in cardiac repair post-MI. This study investigates the NKRF mechanism in cardiac remodeling and dysfunction post-MI by establishing a CF-specific NKRF-knockout (NKRF-CKO) mouse model. NKRF expression is downregulated in CFs in response to pathological cardiac remodeling in vivo and TNF-α in vitro. NKRF-CKO mice demonstrate worse cardiac function and survival and increased infarct size, heart weight, and MMP2 and MMP9 expression post-MI compared with littermates. NKRF inhibits CF migration and invasion in vitro by downregulating MMP2 and MMP9 expression. Mechanistically, NKRF inhibits human antigen R (HuR) transcription by binding to the classical negative regulatory element within the HuR promoter via an NF-κB-dependent mechanism. This decreases HuR-targeted Mmp2 and Mmp9 mRNA stability. This study suggests that NKRF is a therapeutic target for pathological cardiac remodeling.

Cardiac patches made of brown adipose-derived stem cell sheets and conductive electrospun nanofibers restore infarcted heart for ischemic myocardial infarction.

Cell sheet engineering has been proven to be a promising strategy for cardiac remodeling post-myocardial infarction. However, insufficient mechanical strength and low cell retention lead to limited therapeutic efficiency. The thickness and area of artificial cardiac patches also affect their therapeutic efficiency. Cardiac patches prepared by combining cell sheets with electrospun nanofibers, which can be transplanted and sutured to the surface of the infarcted heart, promise to solve this problem. Here, we fabricated a novel cardiac patch by stacking brown adipose-derived stem cells (BADSCs) sheet layer by layer, and then they were combined with multi-walled carbon nanotubes (CNTs)-containing electrospun polycaprolactone/silk fibroin nanofibers (CPSN). The results demonstrated that BADSCs tended to generate myocardium-like structures seeded on CPSN. Compared with BADSCs suspension-containing electrospun nanofibers, the transplantation of the CPSN-BADSCs sheets (CNBS) cardiac patches exhibited accelerated angiogenesis and decreased inflammation in a rat myocardial infarction model. In addition, the CNBS cardiac patches could regulate macrophage polarization and promote gap junction remodeling, thus restoring cardiac functions. Overall, the hybrid cardiac patches made of electrospun nanofibers and cell sheets provide a novel solution to cardiac remodeling after ischemic myocardial infarction.

Inhibition of intraflagellar transport protein-88 promotes epithelial-to-mesenchymal transition and reduces cardiac remodeling post-myocardial infarction

The epicardium is a potential source of cardiac progenitors to support reparative angiogenesis after myocardial infarction (MI) through epithelial-to-mesenchymal transition (EMT). Primary cilia are recognized as hubs of cellular signaling, and their presence can alter downstream pathways to modulate EMT. The present study aimed to examine the effects of inhibiting intraflagellar transport protein-88 (Ift88), a protein vital to ciliary assembly, on epicardial EMT and cardiac remodeling post-MI. Epicardium derived cells (EPDCs) were cultured from E13.5 heart explants and treated with adenoviral vector encoding short-hairpin RNA against the mouse Ift88 (Ad-shIft88) to disassemble the primary cilium. Effects of Ad-shIft88 on epicardial EMT and cardiac remodeling were examined in mice post-MI. Our results show that Ad-shIft88 enhanced EMT of cultured EPDCs. In adult mice, intra-myocardial administration of Ad-shIft88 increased the number of Wilms tumor 1 (Wt1) positive cells in the epicardium and myocardium, promoted expression of genes associated with epicardial EMT, and enhanced capillary and arteriolar densities post-MI. Additionally, intra-myocardial Ad-shIft88 treatment attenuated cardiac hypertrophy and improved myocardial function three weeks post-MI. In conclusion, knockdown of Ift88 improves epicardial EMT, neovascularization and cardiac remodeling in the ischemic heart. Our study highlights the primary cilium as a potential therapeutic target post-MI.

Synthetic Fibroblasts: Terra Incognita in Cardiac Regeneration.

Ischemic heart disease, a major risk factor for myocardial infarction (MI), occurs when the blood vessels supplying oxygen-rich blood to the heart become partially or fully occluded by lipid-rich plaques, resulting in myocardial cell death, remodeling, and scarring. In addition, MI occurs as result of lipid-rich plaque rupture, resulting in thrombosis and vessel occlusion. Cardiac fibroblasts (CFs) and CF-derived growth factors are crucial post-MI in myocardial remodeling. Information regarding the regenerative phenotypes of CFs is scarce; however, regenerative CFs are translationally relevant in myocardial regeneration following MI. The emerging technologies in regenerative cardiology offer cutting-edge translational opportunities, including synthetic cells. In this review, we critically reviewed the current knowledge and the ongoing research efforts on application of synthetic cells for improving cardiac regeneration post-MI. Impact statement Synthetic cells offer tremendous regenerative potential in otherwise deleterious cardiac remodeling postmyocardial infarction. Understanding the role of fibroblasts in cardiac healing and the therapeutic applications of synthetic cells would open a multitude of novel cardiac regenerative approaches. The novel concept of synthetic fibroblasts that emulate native cardiac fibroblasts can provide an effective solution in cardiac healing.

Sex differences in cardiac remodeling post myocardial infarction with acute cigarette smoking

BackgroundWhether cigarette smoking affects the heart post-myocardial infarction (MI) in a sex-dependent way remains controversial. Using a mouse model, we investigated cardiac remodeling under the influence of acute cigarette smoke (CS) exposure following ischemic injury in both sexes.MethodsTen cigarettes were smoked twice daily for 2 weeks followed by MI and then 1 additional week post permanent LAD ligation. Cardiac function, histology, and infarct size were assessed, and inflammatory markers quantified by RT–PCR. Statistical comparisons were performed using an unpaired t test or ANOVA followed by Tukey post hoc test.ResultsWe observed that cigarette smoking exacerbated both left and right ventricular remodeling only in males at an early stage of post-MI. Females did not display a significant structural and/or functional alteration within 7 days of cardiac remodeling post-MI upon CS exposure. Worsened right ventricular remodeling in males was independent of pulmonary congestion. CS-exposed males exhibited enhanced increases in left ventricular end systolic and diastolic volumes, as well as reductions in ejection fraction and fractional area changes of left ventricular base. At day 7, infarct size was increased by cigarette smoking in males only, which was accompanied by enhanced collagen deposition in both the infarcted and peri-infarcted areas. Both IL-6 and TNF-α mRNA expression significantly increased in CS-exposed MI male group only at day 7 post-MI suggestive of prolonged inflammation.ConclusionsThese findings indicate that CS exposure worsens the progression of cardiac remodeling post-MI in male sex in a significant manner compared to female sex at least at early stages.

Intramyocardial injected human umbilical cord-derived mesenchymal stem cells (HucMSCs) contribute to the recovery of cardiac function and the migration of CD4+ T cells into the infarcted heart via CCL5/CCR5 signaling

BackgroundHuman umbilical cord-derived mesenchymal stem cells (HucMSCs) have been recognized as a promising cell for treating myocardial infarction (MI). Inflammatory response post MI is critical in determining the cardiac function and subsequent adverse left ventricular remodeling. However, the local inflammatory effect of HucMSCs after intramyocardial injection in murine remains unclear.MethodsHucMSCs were cultured and transplanted into the mice after MI surgery. Cardiac function of mice were analyzed among MI-N.S, MI-HucMSC and MI-HucMSC-C–C Motif Chemokine receptor 5 (CCR5) antagonist groups, and angiogenesis, fibrosis and hypertrophy, and immune cells infiltration of murine hearts were evaluated between MI-N.S and MI-HucMSC groups. We detected the expression of inflammatory cytokines and their effects on CD4+ T cells migration.ResultsHucMSCs treatment can significantly improve the cardiac function and some cells can survive at least 28 days after MI. Intramyocardial administration of HucMSCs also improved angiogenesis and alleviated cardiac fibrosis and hypertrophy. Moreover, we found the much higher numbers of CD4+ T cells and CD4+FoxP3+ regulatory T cells (Tregs) in the heart with HucMSCs than that with N.S treatment on day 7 post MI. In addition, the protein level of C–C Motif Chemokine Ligand 5 (CCL5) greatly increased in HucMSCs treated heart compared to MI-N.S group. In vitro, HucMSCs inhibited CD4+ T cells migration and addition of CCL5 antibody or CCR5 antagonist significantly reversed this effect. In vivo results further showed that addition of CCR5 antagonist can reduce the cardioprotective effect of HucMSCs administration on day 7 post MI injury.ConclusionThese findings indicated that HucMSCs contributed to cardiac functional recovery and attenuated cardiac remodeling post MI. Intramyocardial injection of HucMSCs upregulated the CD4+FoxP3+ Tregs and contributed to the migration of CD4+ T cells into the injured heart via CCL5/CCR5 pathway.

Curcumin Ameliorates Cardiac Fibrosis by Regulating Macrophage-Fibroblast Crosstalk via IL18-P-SMAD2/3 Signaling Pathway Inhibition.

Ethnopharmacological relevance: Curcumin is a bright yellow chemical produced by plants of the Curcuma longa species. Chemically, curcumin is a diarylheptanoid, belonging to the group of curcuminoids. The therapeutic potential of curcumin has been widely investigated, including its utilization in various of cardiovascular diseases. However, its effect in cardiac remodeling post myocardial infarction and underlying mechanism remains to be uncover. Aim: To evaluate the therapeutic effect and underlying mechanism of curcumin on cardiac fibrosis after myocardial infarction via macrophage-fibroblast crosstalk. Methods: Male C57BL/6 (C57) mice were subjected to left anterior descending coronary artery ligation to establish myocardial infarction and intragastrically fed vehicle or curcumin (50 mg/kg or 100 mg/kg) for 4 weeks. In parallel, neonatal rat cardiac fibroblasts were isolated and co-cultured with liposaccharide (LPS− or LPS+) curcumin-treated macrophages, followed by TGF-β stimulation for 24 h. Cardiac function was determined by 2-dimensional echocardiography, and cardiac fibrosis was measured by picrosirius red staining. Apoptosis of macrophages was investigated by flow cytometry; all pro-fibrotic protein expression (EDA-Fibronectin, Periostin, Vimentin, and α-SMA) as well as TGF-βR1 downstream signaling activation reflected by phosphorylated SMAD2/3 (p-SMAD2 and p-SMAD3) were demonstrated by western blotting. Results: Curcumin significantly ameliorated the inflammation process subsequent to myocardial infarction, reflected by decreased expression of CD68+ and CD3+ cells, accompanied by dramatically improved cardiac function compared with the placebo group. In addition, cardiac fibrosis is inhibited by curcumin administration. Interestingly, no significant reduction in fibrotic gene expression was observed when isolated cardiac fibroblasts were directly treated with curcumin in vitro; however, pro-fibrotic protein expression was significantly attenuated in CF, which was co-cultured with LPS-stimulated macrophages under curcumin treatment compared with the placebo group. Mechanistically, we discovered that curcumin significantly downregulated pro-inflammatory cytokines in macrophages, which in turn inhibited IL18 expression in co-cultured cardiac fibroblasts using bulk RNA sequencing, and the TGF-β1-p-SMAD2/3 signaling network was also discovered as the eventual target downstream of IL18 in curcumin-mediated anti-fibrosis signaling. Conclusion: Curcumin improves cardiac function and reduces cardiac fibrosis after myocardial infarction. This effect is mediated by the inhibition of macrophage-fibroblast crosstalk in the acute phase post-MI and retrained activation of IL18-TGFβ1-p-SMAD2/3 signaling in cardiac fibroblasts.

Augmented early aged neutrophil infiltration contributes to late remodeling post myocardial infarction.

Neutrophils oscillate in number and phenotype after being released from bone marrow. Myocardial infarction (MI) outcome is associated with the time-of-day of ischemia onset. However, the underlying contributive factors of neutrophils to cardiac remodeling post MI remain unknown. We examined neutrophil infiltration into the heart and cardiac function and remodeling in C57BL/6J MI model created by permanent coronary ligation at different zeitgeber times (ZT). We found that cell surface markers (CD62L, CXCR2, CXCR4) of neutrophils in peripheral blood lost diurnal oscillation 24h post MI. Meanwhile, circadian gene Bmal1, Nr1d1, and Clock mRNA expression displayed disrupted diurnal patterns. Flow cytometry showed augmented aged neutrophil (CD11b+Ly6G+CD62Llow) infiltration into the heart along with increased circulating aged neutrophils in MI groups with more infiltration at ZT5 (p<0.05), but no difference for aged neutrophil infiltration at different ZT points in late stage. Infiltrated neutrophils had significantly higher CXCL2 and CXCR2 but lower CXCR4 gene expression (p<0.05). Mice that underwent ligation at ZT5 had high mortality rate and large infarct size. Echocardiography showed that those mice had significantly larger end diastolic and systolic volume and lower ejection fraction (p<0.05). Immunohistology revealed that those mice displayed more fibrosis, cardiomyocyte hypertrophy, and less angiogenesis compared to ZT13 or ZT21 group (p<0.05). However, treatment with anti-CXCL2 antibody significantly reduced LV dilatation, fibrosis, hypertrophy and improved cardiac function. These results indicate greater aged neutrophil infiltration into the heart contributes to cardiac hypertrophy, fibrosis, and dysfunction which suggests that blocking neutrophil aging may be a therapeutic alternative following acute myocardial infarction.

Plaque and remodeling markers in coronary thrombi

Abstract Background Matrix Metalloproteinases (MMPs) and their inhibitors are considered to be of importance in development of atherosclerotic coronary artery disease. MMP-9 has been associated with unstable atherosclerotic plaques and rupture, as well as left ventricular remodeling after myocardial infarction (MI), whereas MMP-2 seems to be more related to progression of stable plaques. MMP activity is modulated by Tissue Inhibitors of Metalloproteinases (TIMPs). TIMP-1 has been associated with cardiac remodeling post MI, and TIMP-2 has been discussed to inhibit plaque development and destabilization. The extracellular MMP Inducer, EMMPRIN, stimulates both MMPs and TIMPs, and has been found upregulated on the surface of monocytes in patients with acute MI, and associated with MMP-9 activity. Purpose To study whether genes encoding MMP-2, MMP-9, TIMP-1, TIMP-2 and EMMPRIN are expressed in coronary thrombi and in circulating leukocytes from STEMI patients, and whether these are related to the degree of myocardial injury measured by troponin T, and time from symptoms to PCI. Methods Intracoronary thrombi were aspirated from 33 patients with ST-elevation myocardial infarction (STEMI) treated with primary PCI. The thrombi were snap-frozen in RNA-later solution for gene expression analyses. Peripheral blood samples with Pax-gene tubes were drawn at end of the PCI procedure. RNA was isolated from the thrombi and leukocytes, and the actual genes relatively quantified by RT PCR. Peak troponin T was collected from clinical records. Results Genes coding for the five different markers were present in 84–100% of the thrombi. Median peak troponin T was 3434 m/L. The expression of TIMP-1 in the thrombi correlated significantly to peak troponin T (r=0.393, p=0.026), and dividing peak troponin T values into quartiles, the median value of TIMP-1 mRNA in Q4 was 2.5-fold higher compared to Q1–3 (p=0.107). Peak troponin T also correlated to the expression of TIMP-1 in circulating leukocytes (r=0.469, p=0.006), and in Q4 of troponin T, the median value was 1.6-fold higher compared to Q1–3 (p=0.056). There were no significant correlations between the other measured genes and troponin T, and also no associations of any genes expressed in the thrombi or in circulating leukocytes to time from symptom to PCI (median 152 min). Conclusion Genes coding for MMP-2, MMP-9, TIMP-1, TIMP-2 and EMMPRIN were highly expressed in human coronary thrombi. The positive correlation between peak troponin T and the expression of TIMP-1 both in thrombi and in circulating leukocytes at time of PCI in patients with STEMI, may indicate that the role of TIMP-1 is important in cardiac remodeling immediately post-MI. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Stein Erik Hagens Foundation for Clinical Heart Research

Empagliflozin prevents from early cardiac injury post myocardial infarction in non-diabetic mice

ObjectivesSodium-glucose cotransporter 2 (SGLT2) inhibitors have been confirmed to reduce the rate of rehospitalization for heart failure and cardiovascular death in diabetic patients. The aim of our study was to investigate the cardioprotective role of SGLT2 inhibitors in early myocardial infarction (MI) of non-diabetic mice. MethodsC57BL/6 mice underwent left artery coronary artery descending (LAD) ligation to induce MI. Following the surgery, animals were randomized to receive saline or empagliflozin. Empagliflozin (EMPA) was administrated at 10 mg/kg per day by oral gavage for 2 weeks. Echocardiography, histological staining and qualitative RT-PCR were performed to assess the cardiac remodeling post MI. In vitro experiments were performed to evaluate the effect of empagliflozin on apoptosis, oxidative stress and mitochondrial membrane potential of cardiomyocyte subjected to hypoxic treatment. ResultsCompared with MI group, the empagliflozin treatment group showed improved cardiac function, reduced infarct size and interstitial fibrosis. Empagliflozin also inhibited cardiomyocyte apoptosis by alleviating oxidative stress and restoring mitochondrial membrane potential. Immunoblotting analysis revealed activated AMP-activated protein kinase (AMPK) signaling may mediated the cardioprotective role of empagliflozin. ConclusionsIn summary, empagliflozin could inhibit cardiomyocyte apoptosis and improve cardiac remodeling early MI, which provided insights into the benefic effect of empagliflozin on MI patients without diabetes.

Biophysical and Lipidomic Biomarkers of Cardiac Remodeling Post-Myocardial Infarction in Humans.

Few studies have analyzed the potential of biophysical parameters as markers of cardiac remodeling post-myocardial infarction (MI), particularly in human hearts. Fourier transform infrared spectroscopy (FTIR) illustrates the overall changes in proteins, nucleic acids and lipids in a single signature. The aim of this work was to define the FTIR and lipidomic pattern for human left ventricular remodeling post-MI. A total of nine explanted hearts from ischemic cardiomyopathy patients were collected. Samples from the right ventricle (RV), left ventricle (LV) and infarcted left ventricle (LV INF) were subjected to biophysical (FTIR and differential scanning calorimetry, DSC) and lipidomic (liquid chromatography–high-resolution mass spectrometry, LC–HRMS) studies. FTIR evidenced deep alterations in the myofibers, extracellular matrix proteins, and the hydric response of the LV INF compared to the RV or LV from the same subject. The lipid and esterified lipid FTIR bands were enhanced in LV INF, and both lipid indicators were tightly and positively correlated with remodeling markers such as collagen, lactate, polysaccharides, and glycogen in these samples. Lipidomic analysis revealed an increase in several species of sphingomyelin (SM), hexosylceramide (HexCer), and cholesteryl esters combined with a decrease in glycerophospholipids in the infarcted tissue. Our results validate FTIR indicators and several species of lipids as useful markers of left ventricular remodeling post-MI in humans.

Abstract 486: Chronic Periodontitis Induces Adverse Post-myocardial Wound Healing Through Activation of CD8+ T-cells

Increased risk of adverse cardiac remodeling post-myocardial infarction (MI) has been observed in patients with periodontal disease. Previously, we demonstrated that chronic inflammation induced by periodontal pathogen Porphyromonas gingivalis lipopolysaccharide (LPS) resets cardiac homeostasis, causing acceleration and exacerbation of the macrophage response post-MI. We hypothesize that chronic LPS activates a memory T-cell response resulting in adverse cardiac remodeling post-MI. Analysis of the mouse heart attack research tool (mHART) 1.0 identified 135 mice (5.4 ± 0.1 months of age) associated with the LPS study that had both echo and plasma data collected. Of these 26 mice also had tissue blocks in the mHART tissue bank. Mice were grouped as follows: 1) Saline day 0 unoperated mice (D0), 2) 28 day LPS day 0 unoperated mice (LPS), 3) Saline day 1 MI (MI), and 4) 28 day LPS day 1 MI (LPS+MI). Immunofluorescence of the left ventricle (LV) demonstrated that chronic LPS increased the number of memory CD8+ T-cells (CD3+CD8+CD27+) in the LV and remained elevated in the LPS+MI group compared to D0 and MI controls. Similar to chronic LPS, ligature-induced periodontitis (21 days) also showed upregulation of CD8+ T-cells in the LV along with changes in plasma proteins associated with interleukin, cytokine, chemokine receptor binding, peptide ligand-binding, inflammasome pathway, class A/1 rhodopsin-like receptors, G-protein coupled receptor ligand binding, and RUNX1 and FOXP3 control of Treg development and signaling. To dissect T-cell mediated signaling pathways, we constantly infused an MHC-I blocking antibody (MHCi; 0.2 μg/day; n=3) by osmotic mini-pumps implanted subcutaneously 7 days before (21 days after LPS infusion) and after MI surgery. Interestingly, MHCi attenuated the effector CD8+ T-cell response (CD3+CD8+CD44+) without affecting the memory response. MHCi also attenuated macrophage numbers within the infarct, thereby improving cardiac function at post-MI day 1. Our data showed the recruitment of effector but not memory CD8+ T-cells is regulating macrophage-mediated adverse post-MI remodeling in the setting of chronic periodontitis.

IL-33 induces type-2-cytokine phenotype but exacerbates cardiac remodeling post-myocardial infarction with eosinophil recruitment, worsened systolic dysfunction, and ventricular wall rupture

Myocardial infarction (MI) is the leading cause of mortality worldwide. Interleukin (IL)-33 (IL-33) is a cytokine present in most cardiac cells and is secreted on necrosis where it acts as a functional ligand for the ST2 receptor. Although IL-33/ST2 axis is protective against various forms of cardiovascular diseases, some studies suggest potential detrimental roles for IL-33 signaling. The aim of the present study was to examine the effect of IL-33 administration on cardiac function post-MI in mice. MI was induced by coronary artery ligation. Mice were treated with IL-33 (1 μg/day) or vehicle for 4 and 7 days. Functional and molecular changes of the left ventricle (LV) were assessed. Single cell suspensions were obtained from bone marrow, heart, spleen, and peripheral blood to assess the immune cells using flow cytometry at 1, 3, and 7 days post-MI in IL-33 or vehicle-treated animals. The results of the present study suggest that IL-33 is effective in activating a type 2 cytokine milieu in the damaged heart, consistent with reduced early inflammatory and pro-fibrotic response. However, IL-33 administration was associated with worsened cardiac function and adverse cardiac remodeling in the MI mouse model. IL-33 administration increased infarct size, LV hypertrophy, cardiomyocyte death, and overall mortality rate due to cardiac rupture. Moreover, IL-33-treated MI mice displayed a significant myocardial eosinophil infiltration at 7 days post-MI when compared with vehicle-treated MI mice. The present study reveals that although IL-33 administration is associated with a reparative phenotype following MI, it worsens cardiac remodeling and promotes heart failure.

Prevascularized, multiple-layered cell sheets of direct cardiac reprogrammed cells for cardiac repair.

We previously demonstrated that the efficiency of direct cardiac reprogramming from fibroblasts could be enhanced via mimicking of the in vivo cardiac microenvironment through coculture with cardiomyocytes and by providing electric cues. In the present study, we developed cell sheets using the direct cardiac reprogrammed cells and a nanothin, nanoporous poly(lactic-co-glycolic acid) membrane. Cell sheets were laid layer-by-layer and prevacularized with endothelial cells between the layers. These prevascularized, multilayered cell sheets were implanted on the epicardium of infarcted rat hearts, which led to an improvement in cardiac function and reduction in adverse cardiac remodeling post-myocardial infarction (MI). Thus, the in vivo mimicking direct cardiac reprogramming and prevascularization technique can enhance the efficiency of cell sheets in clinical applications and provide new opportunities to prevent heart failure following MI.

Implications of the transcription factor WT1 linked to the pathologic cardiac remodeling post-myocardial infarction

New advances in the treatment of acute myocardial infarction involve novel signalling pathways and cellular progeny. In this sense, regeneration is a novel tool that would contribute to post-infarction physiological ventricular remodeling. More specifically, re-expression of the WT1 transcription factor in the myocardial wall by ischaemia and infarction would be related to the invasion of cells with the capacity for regeneration. This mechanism seems not to be sufficient to restore muscle cells and lost vessels entirely. Of particular interest, the presence of the heat-shock response protein 70 (Hsp70) and its interaction with the vitamin D receptor would modulate the expression of WT1 positively. In this context, it is proposed that the activation of vitamin D receptors associated with Hsp70 could favour physiological cardiac remodeling and reduce the progression to heart failure.