Cardiac reprogramming reduces inflammatory macrophages and improves cardiac function in chronic myocardial infarction.

Cardiomyocytes (CMs) have little regenerative capacity. After myocardial infarction (MI), scar formation and myocardial remodeling proceed in the infarct and non-infarct areas, respectively, leading to heart failure (HF). Prolonged activation of cardiac fibroblasts (CFs) and inflammatory cells may contribute to this process; however, therapies targeting these cell types remain lacking. Cardiac reprogramming converts CFs into induced CMs, reduces fibrosis, and improves cardiac function in chronic MI through the overexpression of Mef2c/Gata4/Tbx5/Hand2 (MGTH). However, whether cardiac reprogramming reduces inflammation in infarcted hearts remains unclear. Moreover, the mechanism through which MGTH overexpression in CFs affects inflammatory cells remains unknown. Here, we showed that inflammation persists in the myocardium until three months after MI, which can be reversed with cardiac reprogramming. Single-cell RNA sequencing demonstrated that CFs expressed pro-inflammatory genes and exhibited strong intercellular communication with inflammatory cells, including macrophages, in chronic MI. Cardiac reprogramming suppressed the inflammatory profiles of CFs and reduced the relative ratios and pro-inflammatory signatures of cardiac macrophages. Moreover, fluorescence-activated cell sorting analysis (FACS) revealed that cardiac reprogramming reduced the number of chemokine receptor type 2 (CCR2)-positive inflammatory macrophages in the non-infarct areas in chronic MI, thereby restoring myocardial remodeling. Thus, cardiac reprogramming reduced the number of inflammatory macrophages to exacerbate cardiac function after MI.

MRP1-Dependent Extracellular Release of Glutathione Induces Cardiomyocyte Ferroptosis After Ischemia-Reperfusion.

BACKGROUND: The membrane components of cardiomyocytes are rich in polyunsaturated fatty acids, which are easily oxidized. Thus, an efficient glutathione-based lipid redox system is essential for maintaining cellular functions. However, the relationship between disruption of the redox system during ischemia-reperfusion (IR), oxidized lipid production, and consequent cell death (ferroptosis) remains unclear. We investigated the mechanisms underlying the disruption of the glutathione-mediated reduction system related to ferroptosis during IR and developed intervention strategies to suppress ferroptosis. METHODS: In vivo fluctuations of both intra- and extracellular metabolite levels during IR were explored via microdialysis and tissue metabolome analysis. Oxidized phosphatidylcholines were assessed using liquid chromatography high-resolution mass spectrometry. The areas at risk following IR were assessed using triphenyl-tetrazolium chloride/Evans blue stain. RESULTS: Metabolomic analysis combined with microdialysis revealed a significant release of glutathione from the ischemic region into extracellular spaces during ischemia and after reperfusion. The release of glutathione into extracellular spaces and a concomitant decrease in intracellular glutathione concentrations were also observed during anoxia-reperfusion in an in vitro cardiomyocyte model. This extracellular glutathione release was prevented by chemical inhibition or genetic suppression of glutathione transporters, mainly MRP1 (multidrug resistance protein 1). Treatment with MRP1 inhibitor reduced the intracellular reactive oxygen species levels and lipid peroxidation, thereby inhibiting cell death. Subsequent in vivo evaluation of endogenously oxidized phospholipids following IR demonstrated the involvement of ferroptosis, as levels of multiple oxidized phosphatidylcholines were significantly elevated in the ischemic region 12 hours after reperfusion. Inhibition of the MRP1 transporter also alleviated intracellular glutathione depletion in vivo and significantly reduced the generation of oxidized phosphatidylcholines. Administration of MRP1 inhibitors significantly attenuated infarct size after IR injury. CONCLUSIONS: Glutathione was released continuously during IR, primarily in an MRP1-dependent manner, and induced ferroptosis. Suppression of glutathione release attenuated ferroptosis and reduced myocardial infarct size following IR.

Immune and Inflammatory Networks in Myocardial Infarction: Current Research and Its Potential Implications for the Clinic.

Despite recent scientific and technological advances, myocardial infarction (MI) still represents a major global health problem, leading to high morbidity and mortality worldwide. During the post-MI wound healing process, dysregulated immune inflammatory pathways and failure to resolve inflammation are associated with maladaptive left ventricular remodeling, progressive heart failure, and eventually poor outcomes. Given the roles of immune cells in the host response against tissue injury, understanding the involved cellular subsets, sources, and functions is essential for discovering novel therapeutic strategies that preserve the protective immune system and promote optimal healing. This review discusses the cellular effectors and molecular signals across multi-organ systems, which regulate the inflammatory and reparative responses after MI. Additionally, we summarize the recent clinical and preclinical data that propel conceptual revolutions in cardiovascular immunotherapy.

Qualitative and Quantitative Effects of Fatty Acids Involved in Heart Diseases.

Fatty acids (FAs) have structural and functional diversity. FAs in the heart are closely associated with cardiac function, and their qualitative or quantitative abnormalities lead to the onset and progression of cardiac disease. FAs are important as an energy substrate for the heart, but when in excess, they exhibit cardio-lipotoxicity that causes cardiac dysfunction or heart failure with preserved ejection fraction. FAs also play a role as part of phospholipids that compose cell membranes, and the changes in mitochondrial phospholipid cardiolipin and the FA composition of plasma membrane phospholipids affect cardiomyocyte survival. In addition, FA metabolites exert a wide variety of bioactivities in the heart as lipid mediators. Recent advances in measurement using mass spectrometry have identified trace amounts of n-3 polyunsaturated fatty acids (PUFAs)-derived bioactive metabolites associated with heart disease. n-3 PUFAs have a variety of cardioprotective effects and have been shown in clinical trials to be effective in cardiovascular diseases, including heart failure. This review outlines the contributions of FAs to cardiac function and pathogenesis of heart diseases from the perspective of three major roles and proposes therapeutic applications and new medical perspectives of FAs represented by n-3 PUFAs.

Pharmacokinetics of hydrogen after ingesting a hydrogen-rich solution: A study in pigs.

Drinking hydrogen (H2)-rich water is a common way to consume H2. Although many studies have shown efficacy of drinking H2-rich water in neuropsychiatric and endocrine metabolic disorders, their authenticity has been questioned because none examined the associated pharmacokinetics of H2. Therefore, we performed the first study to investigate the pharmacokinetics of H2 in pigs given an H2-rich glucose solution with the aim to extrapolate the findings to humans. We inserted blood collection catheters into the jejunal and portal veins, suprahepatic inferior vena cava, and carotid artery of 4 female pigs aged 8 weeks. Then, within 2 min we infused 500 ml of either H2-rich or H2-free glucose solution into the jejunum via a percutaneous gastrostomy tube and measured changes in H2 concentration in venous and arterial blood over 120 min. After infusion of the H2-rich glucose solution, H2 concentration in the portal vein peaked at 0.05 mg/L and remained at more than 0.016 mg/L (H2 saturation level, 1%) after 1 h; it also increased after infusion of H2-free glucose solution but remained below 0.001 mg/L (H2 saturation level, 0.06%). We assume that H2 was subsequently metabolized in the liver or eliminated via the lungs because it was not detected in the carotid artery. In conclusion, drinking highly concentrated H2-rich solution within a short time is a good way to increase H2 concentration in portal blood and supply H2 to the liver.

Time-Series Transcriptome Analysis Reveals the miR-27a-5p-Ppm1l Axis as a New Pathway Regulating Macrophage Alternative Polarization After Myocardial Infarction.

BACKGROUND: Timely differentiation of monocytes into M2-like macrophages is important in the cardiac healing process after myocardial infarction (MI), but molecular mechanisms governing M2-like macrophage differentiation at the transcriptional level after MI have not been fully understood.Methods and Results:A time-series microarray analysis of mRNAs and microRNAs in macrophages isolated from the infarcted myocardium was performed to identify the microRNAs involved in regulating the process of differentiation to M2-like macrophages. Correlation analysis revealed 7 microRNAs showing negative correlations with the progression of polarity changes towards M2-like subsets. Next, correlation coefficients for the changes in expression of mRNAs and miRNAs over time were calculated for all combinations. As a result, miR-27a-5p was extracted as a possible regulator of the largest number of genes in the pathway for the M2-like polarization. By selecting mouse mRNAs and human mRNAs possessing target sequences of miR-27a-5p and showing expression patterns inversely correlated with that of miR-27a-5p, 8 potential targets of miR-27a-5p were identified, includingPpm1l. Using the mouse bone marrow-derived macrophages undergoing differentiation into M2-like subsets by interleukin 4 stimulation, we confirmed that miR-27a-5p suppressed M2-related genes by negatively regulatingPpm1lexpression. CONCLUSIONS: Ppm1land miR-27a-5p may be the key molecules regulating M2-like polarization, with miR-27a-5p inhibiting the M2-like polarization through downregulation ofPpm1lexpression.

Peripheral pulmonary stenosis with Noonan syndrome treated by balloon pulmonary angioplasty.

Noonan syndrome is known to have various cardiovascular defects, which include pulmonary artery stenosis. Pulmonary artery stenosis is characterized by obstruction of pulmonary artery blood flow that can cause elevated pulmonary artery pressure and ventilation-perfusion inequality, which can cause dyspnea on exertion and eventually, heart failure. Although the etiology of pulmonary artery stenosis related to congenital diseases is still unknown, balloon pulmonary angioplasty has being reported to be effective to selected patients with Alagille and Williams syndromes, but not from Noonan syndrome despite of modest prevalence of pulmonary artery stenosis. Here, we report the first Noonan syndrome patient with pulmonary artery stenosis who underwent successful balloon pulmonary angioplasty. The strategy used in balloon pulmonary angioplasty was planned with careful morphologic evaluation by computed tomographic angiography, and performed with scoring balloons in a graded approach with multiple sessions. After balloon pulmonary angioplasty, we confirmed maintained dilation of lesions and symptom alleviation, suggesting that balloon pulmonary angioplasty can be performed safely on pulmonary artery stenosis in a Noonan syndrome patient.

MerTK Expression and ERK Activation Are Essential for the Functional Maturation of Osteopontin-Producing Reparative Macrophages After Myocardial Infarction.

Background We previously reported that osteopontin plays an essential role in accelerating both reparative fibrosis and clearance of dead cells (efferocytosis) during tissue repair after myocardial infarction (MI) and galectin-3hiCD206+ macrophages is the main source of osteopontin in post-MI heart. Interleukin-10- STAT3 (signal transducer and activator of transcription 3)-galectin-3 axis is essential for Spp1 (encoding osteopontin) transcriptional activation in cardiac macrophages after MI. Here, we investigated the more detailed mechanism responsible for functional maturation of osteopontin-producing macrophages. Methods and Results In post-MI hearts, Spp1 transcriptional activation occurred almost exclusively in MerTK (Mer tyrosine kinase)+ galectin-3hi macrophages. The induction of MerTK on galectin-3hi macrophages is essential for their functional maturation including efferocytosis and Spp1 transcriptional activity. MerTK+galectin-3hi macrophages showed a strong activation of both STAT3 and ERK (extracellular signal-regulated kinase). STAT3 inhibition suppressed the differentiation of osteopontin-producing MerTK+galectin-3hi macrophages, however, STAT3 activation was insufficient at inducing Spp1 transcriptional activity. ERK inhibition suppressed Spp1 transcriptional activation without affecting MerTK or galectin-3 expression. Concomitant activation of ERK is required for transcriptional activation of Spp1. In Il-10 knockout enhanced green fluorescent protein-Spp1 knock-in mice subjected to MI, osteopontin-producing macrophages decreased but did not disappear entirely. Interleukin-10 and macrophage colony-stimulating factor synergistically activated STAT3 and ERK and promoted the differentiation of osteopontin-producing MerTK+galectin-3hi macrophages in bone marrow-derived macrophages. Coadministration of anti-interleukin-10 plus anti-macrophage colony-stimulating factor antibodies substantially reduced the number of osteopontin-producing macrophages by more than anti-interleukin-10 antibody alone in post-MI hearts. Conclusions Interleukin-10 and macrophage colony-stimulating factor act synergistically to activate STAT3 and ERK in cardiac macrophages, which in turn upregulate the expression of galectin-3 and MerTK, leading to the functional maturation of osteopontin-producing macrophages.

Artificial intelligence to predict needs for urgent revascularization from 12-leads electrocardiography in emergency patients.

BACKGROUND: Patient with acute coronary syndrome benefits from early revascularization. However, methods for the selection of patients who require urgent revascularization from a variety of patients visiting the emergency room with chest symptoms is not fully established. Electrocardiogram is an easy and rapid procedure, but may contain crucial information not recognized even by well-trained physicians. OBJECTIVE: To make a prediction model for the needs for urgent revascularization from 12-lead electrocardiogram recorded in the emergency room. METHOD: We developed an artificial intelligence model enabling the detection of hidden information from a 12-lead electrocardiogram recorded in the emergency room. Electrocardiograms obtained from consecutive patients visiting the emergency room at Keio University Hospital from January 2012 to April 2018 with chest discomfort was collected. These data were splitted into validation and derivation dataset with no duplication in each dataset. The artificial intelligence model was constructed to select patients who require urgent revascularization within 48 hours. The model was trained with the derivation dataset and tested using the validation dataset. RESULTS: Of the consecutive 39,619 patients visiting the emergency room with chest discomfort, 362 underwent urgent revascularization. Of them, 249 were included in the derivation dataset and the remaining 113 were included in validation dataset. For the control, 300 were randomly selected as derivation dataset and another 130 patients were randomly selected for validation dataset from the 39,317 who did not undergo urgent revascularization. On validation, our artificial intelligence model had predictive value of the c-statistics 0.88 (95% CI 0.84-0.93) for detecting patients who required urgent revascularization. CONCLUSIONS: Our artificial intelligence model provides information to select patients who need urgent revascularization from only 12-leads electrocardiogram in those visiting the emergency room with chest discomfort.