Increase of chymase-dependent angiotensin II-forming activity in circulating mononuclear leukocytes after acute myocardial infarction chymase activity after acute myocardial infarction

Differential gene expression patterns in ST-elevation Myocardial Infarction and Non-ST-elevation Myocardial Infarction

The ST-elevation Myocardial Infarction (STEMI) and Non-ST-elevation Myocardial Infarction (NSTEMI) might occur because of coronary artery stenosis. The gene biomarkers apply to the clinical diagnosis and therapeutic decisions in Myocardial Infarction. The aim of this study was to introduce, enrich and estimate timely the blood gene profiles based on the high-throughput data for the molecular distinction of STEMI and NSTEMI. The text mining data (50 genes) annotated with DisGeNET data (144 genes) were merged with the GEO gene expression data (5 datasets) using R software. Then, the STEMI and NSTEMI networks were primarily created using the STRING server, and improved using the Cytoscape software. The high-score genes were enriched using the KEGG signaling pathways and Gene Ontology (GO). Furthermore, the genes were categorized to determine the NSTEMI and STEMI gene profiles. The time cut-off points were identified statistically by monitoring the gene profiles up to 30 days after Myocardial Infarction (MI). The gene heatmaps were clearly created for the STEMI (high-fold genes 69, low-fold genes 45) and NSTEMI (high-fold genes 68, low-fold genes 36). The STEMI and NSTEMI networks suggested the high-score gene profiles. Furthermore, the gene enrichment suggested the different biological conditions for STEMI and NSTEMI. The time cut-off points for the NSTEMI (4 genes) and STEMI (13 genes) gene profiles were established up to three days after Myocardial Infarction. The study showed the different pathophysiologic conditions for STEMI and NSTEMI. Furthermore, the high-score gene profiles are suggested to measure up to 3 days after MI to distinguish the STEMI and NSTEMI.

Impact of early pericardial fluid chymase activation after cardiac surgery

Introduction

Chymase is a highly destructive serine protease rapidly neutralized in the circulation by protease inhibitors. Here we test whether pericardial fluid (PCF) chymase activation and other inflammatory biomarkers determine intensive care unit length of stay, and explore mechanisms of chymase delivery by extracellular vesicles to the heart.

Methods

PCF was collected from adult patients (17 on-pump; 13 off-pump) 4 h after cardiac surgery. Extracellular vesicles (EVs) containing chymase were injected into Sprague-Dawley rats to test for their ability to deliver chymase to the heart.

Results

The mean intensive care unit (ICU) stay and mean total length of stay was 2.17 ± 3.8 days and 6.41 ± 1.3 days respectively. Chymase activity and 32 inflammatory markers did not differ in on-pump vs. off-pump cardiac surgery. Society of Thoracic Surgeons Predicted Risk of Morbidity and Mortality Score (STS-PROM), 4-hour post-surgery PCF chymase activity and C-X-C motif chemokine ligand 6 (CXCL6) were all independent predictors of ICU and total hospital length of stay by univariate analysis. Mass spectrometry of baseline PCF shows the presence of serine protease inhibitors that neutralize chymase activity. The compartmentalization of chymase within and on the surface of PCF EVs was visualized by immunogold labeling and transmission electron microscopy. A chymase inhibitor prevented EV chymase activity (0.28 fmol/mg/min vs. 14.14 fmol/mg/min). Intravenous injection of PCF EVs obtained 24 h after surgery into Sprague Dawley rats shows diffuse human chymase uptake in the heart with extensive cardiomyocyte damage 4 h after injection.

Discussion

Early postoperative PCF chymase activation underscores its potential role in cardiac damage soon after on- or off-pump cardiac surgery. In addition, chymase in extracellular vesicles provides a protected delivery mechanism from neutralization by circulating serine protease inhibitors.

The Angiotensin-(1-12)/Chymase axis as an alternate component of the tissue renin angiotensin system

The identification of an alternate extended form of angiotensin I composed of the first twelve amino acids at the N-terminal of angiotensinogen has generated new knowledge of the importance of noncanonical mechanisms for renin independent generation of angiotensins. The human sequence of the dodecapeptide angiotensin-(1-12) [N-Asp¹-Arg²-Val³-Tyr⁴-Ile⁵-His⁶-Pro⁷-Phe⁸-His⁹-Leu¹⁰-Va^l1-Ile¹²-COOH] is an endogenous substrate that in the rat has been documented to be present in multiple organs including the heart, brain, kidney, gut, adrenal gland, and the bone marrow. Newer studies have confirmed the existence of Ang-(1-12) as an Ang II-forming substrate in the blood and heart of normal and diseased patients. Studies to-date document that angiotensin II generation from angiotensin-(1-12) does not require renin participation while chymase rather than angiotensin converting enzyme shows high catalytic activity in converting this tissue substrate into angiotensin II directly.

Estrogen Receptors: Therapeutic Perspectives for the Treatment of Cardiac Dysfunction after Myocardial Infarction

Estrogen receptors (ER) mediate functions beyond their endocrine roles, as modulation of cardiovascular, renal, and immune systems through anti-inflammatory and anti-apoptotic effects, preventing necrosis of cardiomyocytes and endothelial cells, and attenuating cardiac hypertrophy. Estradiol (E2) prevents cardiac dysfunction, increases nitric oxide synthesis, and reduces the proliferation of vascular cells, yielding protective effects, regardless of gender. Such actions are mediated by ER (ER-alpha (ERα), ER-beta (ERβ), or G protein-coupled ER (GPER)) through genomic or non-genomic pathways, which regulate cardiovascular function and prevent tissue remodeling. Despite the extensive knowledge on the cardioprotective effects of estrogen, clinical studies conducted on myocardial infarction (MI) and cardiovascular diseases still include favorable and unfavorable profiles. The purpose of this review is to provide up-to-date information regarding molecular, preclinical, and clinical aspects of cardiovascular E2 effects and ER modulation as a potential therapeutic target for the treatment of MI-induced cardiac dysfunction.

Noncanonical Mechanisms for Direct Bone Marrow Generating Ang II (Angiotensin II) Predominate in CD68 Positive Myeloid Lineage Cells

Bone marrow (BM) Ang II (angiotensin II) is a major participant in the regulation of hematopoiesis and immunity. The novel tissue substrate Ang-(1-12) [angiotensin-(1-12)] and its cleaving enzyme chymase are an essential source of Ang II production in cardiac tissue. We hypothesized this noncanonical chymase-mediated Ang II-producing mechanism exists in the BM tissue. Immunohistostaining and flow cytometry confirmed the presence of Ang-(1-12) immunoreaction in the BM of SD (Sprague Dawley) rats. Chymase-mediated Ang II-producing activity in BM was ≈1000-fold higher than ACE (angiotensin-converting enzyme)-mediated Ang II-producing activity (4531±137 and 4.2±0.3 fmol/min per mg, respectively; n=6; P<0.001) and 280-fold higher than chymase activity in the left ventricle of 16.3±1.7 fmol/min per mg (P<0.001). Adding a selective chymase inhibitor, TEI-F00806, eliminated almost all ¹²⁵I-Ang II production. Flow cytometry demonstrated that delta median fluorescence intensity of chymase in cluster of differentiation 68 positive cells was significantly higher than that in cluster of differentiation 68 negative cells (1546±157 and 222±48 arbitrary units, respectively; P=0.0021). Cluster of differentiation 68 positive and side scatter low subsets, considered to be myeloid progenitors, express the highest chymase fluorescence intensity in rat BM. Chymase activity and cellular expression was similar in both male and female rats. In conclusion, myeloid lineage cells, especially myeloid progenitors, have an extraordinary Ang II-producing activity by chymase in the BM.

High Fib4 index in patients with suspected NASH is associated with elevation of chymase-dependent angiotensin II-forming activity in circulating mononuclear leucocytes

Fatal hepatic disease is closely related to non-alcoholic fatty liver disease, especially non-alcoholic steatohepatitis (NASH). NASH is associated with cardiovascular events because it develops on the background of lifestyle-related diseases. Chymase-dependent angiotensin II-forming activity (dAIIFA) in circulating mononuclear leucocytes (CML) is a marker of local angiotensin II production and inflammation. This study investigated the association between CML chymase dAIIFA and NASH. Cardiovascular outpatients were recruited and the Fib4 index (F4I) was calculated. Patients with an F4I > 2.67 were classified into the high F4I group and these patients were strongly suspected to have NASH, while patients with an F4I < 1.30 were classified into the low F4I group. Patient background factors were compared between these groups. CML chymase dAIIFA was measured by ELISA using Nma/Dnp-modified angiotensin I. Among 499 patients, 16% were classified into the high F4I group. Compared with the low F4I group, the high F4I group had a significantly higher age, pancytopenia, more frequent diabetes mellitus, lower diastolic blood pressure, lower estimated glomerular filtration rate, higher brain natriuretic peptide, lower plasma aldosterone concentration, higher total AIIFA, higher CML chymase dAIIFA, and higher pulse wave velocity. Contrary to expectations, the body mass index, triglycerides, and low-density lipoprotein cholesterol were relatively low in the high F4I group. Many cardiovascular outpatients have a high F4I and can probably be categorized as NASH. The high F4I patients had few features of metabolic syndrome and were suspected to have elevated tissue chymase dAIIFA contributing to inflammation in the liver as well as in cardiovascular organs.