Glimepiride, a novel soluble epoxide hydrolase inhibitor, protects against heart failure via increasing epoxyeicosatrienoic acids.

BACKGROUND: Epoxyeicosatrienoic acids (EETs), which exert multiple endogenous protective effects, are hydrolyzed into less active dihydroxyeicosatrienoic acids (DHETs) by soluble epoxide hydrolase (sEH). However, commercial drugs related to EETs or sEH are not yet in clinical use. METHODS: Firstly, the plasma concentration of EETs and DHETs of 316 patients with heart failure (HF) were detected and quantitated by liquid chromatography-tandem mass spectrometry. Then, transverse aortic constriction (TAC)-induced HF was introduced in cardiomyocyte-specific Ephx2-/- mice. Moreover, Western blot, real-time PCR, luciferase reporter, ChIP assays were employed to explore the underlying mechanism. Finally, multiple sEH inhibitors were designed, synthesized, and validated in vitro and in vivo. RESULTS: The ratios of DHETs/EETs were increased in the plasma from patients with HF. Meanwhile, the expression of sEH was upregulated in the heart of patients and mice with HF, especially in cardiomyocytes. Cardiomyocyte-specific Ephx2-/- mice ameliorated cardiac dysfunction induced by TAC. Consistently, Ephx2 knockdown protected Angiotensin II (AngII)-treated cardiomyocytes via increasing EETs in vitro. Mechanistically, AngII could enhance the expression of transcript factor Krüppel-like factor 15 (KLF15), which in turn upregulated sEH. Importantly, glimepiride was identified as a novel sEH inhibitor, which benefited from the elevated EETs during HF. CONCLUSIONS: Glimepiride attenuates HF in mice in part by increasing EETs. CLINICAL TRIAL IDENTIFIER: NCT03461107 (https://clinicaltrials.gov).

CYP450 Epoxygenase Metabolites, Epoxyeicosatrienoic Acids, as Novel Anti-Inflammatory Mediators.

Inflammation plays a crucial role in the initiation and development of a wide range of systemic illnesses. Epoxyeicosatrienoic acids (EETs) are derived from arachidonic acid (AA) metabolized by CYP450 epoxygenase (CYP450) and are subsequently hydrolyzed by soluble epoxide hydrolase (sEH) to dihydroxyeicosatrienoic acids (DHETs), which are merely biologically active. EETs possess a wide range of established protective effects on many systems of which anti-inflammatory actions have gained great interest. EETs attenuate vascular inflammation and remodeling by inhibiting activation of endothelial cells and reducing cross-talk between inflammatory cells and blood vessels. EETs also process direct and indirect anti-inflammatory properties in the myocardium and therefore alleviate inflammatory cardiomyopathy and cardiac remodeling. Moreover, emerging studies show the substantial roles of EETs in relieving inflammation under other pathophysiological environments, such as diabetes, sepsis, lung injuries, neurodegenerative disease, hepatic diseases, kidney injury, and arthritis. Furthermore, pharmacological manipulations of the AA-CYP450-EETs-sEH pathway have demonstrated a contribution to the alleviation of numerous inflammatory diseases, which highlight a therapeutic potential of drugs targeting this pathway. This review summarizes the progress of AA-CYP450-EETs-sEH pathway in regulation of inflammation under different pathological conditions and discusses the existing challenges and future direction of this research field.

[Endogenous protective effects of arachidonic acid epoxygenase metabolites, epoxyeicosatrienoic acids, in cardiovascular system].

The morbidity and mortality of cardiovascular diseases are increasing annually, which is one of the primary causes of human death. Recent studies have shown that epoxyeicosatrienoic acids (EETs), endogenous metabolites of arachidonic acid (AA) via CYP450 epoxygenase, possess a spectrum of protective properties in cardiovascular system. EETs not only alleviate cardiac remodeling and injury in different pathological models, but also improve subsequent hemodynamic disturbances and cardiac dysfunction. Meanwhile, various studies have demonstrated that EETs, as endothelial-derived hyperpolarizing factors, regulate vascular tone by activating various ion channels on endothelium and smooth muscle, which in turn can lower blood pressure, improve coronary blood flow and regulate pulmonary artery pressure. In addition, EETs are protective in endothelium, including inhibiting inflammation and adhesion of endothelial cells, attenuating platelet aggregation, promoting fibrinolysis and revascularization. EETs can also prevent aortic remodeling, including attenuating atherosclerosis, adventitial remodeling, and aortic calcification. Therefore, it is clinically important to study the physiological and pathophysiological effects of EETs in the cardiovascular system to further elucidate the mechanisms, as well as provide new strategy for the prevention and treatment of cardiovascular diseases. This review summarizes the endogenous cardioprotective effects and mechanisms of EETs in order to provide a new insight for research in this field.

CYP2J2 metabolites, epoxyeicosatrienoic acids, attenuate Ang II-induced cardiac fibrotic response by targeting Gα12/13.

The arachidonic acid-cytochrome P450 2J2-epoxyeicosatrienoic acid (AA-CYP2J2-EET) metabolic pathway has been identified to be protective in the cardiovascular system. This study explored the effects of the AA-CYP2J2-EET metabolic pathway on cardiac fibrosis from the perspective of cardiac fibroblasts and underlying mechanisms. In in vivo studies, 8-week-old male CYP2J2 transgenic mice (aMHC-CYP2J2-Tr) and littermates were infused with angiotensin II (Ang II) or saline for 2 weeks. Results showed that CYP2J2 overexpression increased EET production. Meanwhile, impairment of cardiac function and fibrotic response were attenuated by CYP2J2 overexpression. The effects of CYP2J2 were associated with reduced activation of the α subunits of G12 family G proteins (Gα12/13)/RhoA/Rho kinase (ROCK) cascade and elevation of the NO/cyclic guanosine monophosphate (cGMP) level in cardiac tissue. In in vitro studies, cardiac fibroblast activation, proliferation, migration, and collagen production induced by Ang II were associated with activation of the Gα12/13/RhoA/ROCK pathway, which was inhibited by exogenous 11,12-EET. Moreover, silencing of Gα12/13 or RhoA exerted similar effects as 11,12-EET. Furthermore, inhibitory effects of 11,12-EET on Gα12/13 were blocked by NO/cGMP pathway inhibitors. Our findings indicate that enhancement of the AA-CYP2J2-EET metabolic pathway by CYP2J2 overexpression attenuates Ang II-induced cardiac dysfunction and fibrosis by reducing the fibrotic response of cardiac fibroblasts by targeting the Gα12/13/RhoA/ROCK pathway via NO/cGMP signaling.

Epoxyeicosatrienoic acids regulate macrophage polarization and prevent LPS-induced cardiac dysfunction.

Macrophages, owning tremendous phenotypic plasticity and diverse functions, were becoming the target cells in various inflammatory, metabolic and immune diseases. Cytochrome P450 epoxygenase 2J2 (CYP2J2) metabolizes arachidonic acid to form epoxyeicosatrienoic acids (EETs), which possess various beneficial effects on cardiovascular system. In the present study, we evaluated the effects of EETs treatment on macrophage polarization and recombinant adeno-associated virus (rAAV)-mediated CYP2J2 expression on lipopolysaccharide (LPS)-induced cardiac dysfunction, and sought to investigate the underlying mechanisms. In vitro studies showed that EETs (1µmol/L) significantly inhibited LPS-induced M1 macrophage polarization and diminished the proinflammatory cytokines at transcriptional and post-transcriptional level; meanwhile it preserved M2 macrophage related molecules expression and upregulated anti-inflammatory cytokine IL-10. Furthermore, EETs down-regulated NF-κB activation and up-regulated peroxisome proliferator-activated receptors (PPARα/γ) and heme oxygenase 1 (HO-1) expression, which play important roles in regulating M1 and M2 polarization. In addition, LPS treatment in mice induced cardiac dysfunction, heart tissue damage and infiltration of M1 macrophages, as well as the increase of inflammatory cytokines in serum and heart tissue, but rAAV-mediated CYP2J2 expression increased EETs generation in heart and significantly attenuated the LPS-induced harmful effects, which mechanisms were similar as the in vitro study. Taken together, the results indicate that CYP2J2/EETs regulates macrophage polarization by attenuating NF-κB signaling pathway via PPARα/γ and HO-1 activation and its potential use in treatment of inflammatory diseases.

The roles of eicosanoids in myocardial diseases.

Myocardial disease, the abnormalities of the cardiac muscle, is the leading cause of death in humans. Eicosanoids represent a large spectrum of lipid mediators with critical roles in physiological and pathophysiological conditions. Arachidonic acid (AA) is the major resource of eicosanoids and is metabolized via cyclooxygenases (COXs), lipoxygenases (LOXs), and cytochrome P450 (CYP) enzymes producing a diverse family of lipid mediators called eicosanoids, including prostanoids, leukotrienes (LTs), epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid (diHETEs), eicosatetraenoic acids (ETEs), and lipoxins (LXs). Beyond the well-established roles of eicosanoids in inflammation and vascular biology, a growing body of evidence showed that eicosanoids, especially CYP450 derived eicosanoids EETs, are preventive and therapeutic targets for many of the myocardial diseases. EETs not only ameliorate the cardiac injury and remodeling in different pathological models, but also attenuate subsequent hemodynamic disturbances and cardiac dysfunction. EETs have direct and indirect protective properties in the myocardium, and thus relieve dietetic cardiomyopathy and inflammatory cardiomyopathy. Moreover, EETs are capable to attenuate the ischemic cardiomyopathy, including the myocardial infarction and cardiac ischemic reperfusion injury. Multiple biological events and signaling networks are targeted during the myocardial protection of EETs, these are including mitochondria hemostasis, angiogenesis, oxidative stress, inflammatory response, metabolic regulation, endoplasmic reticulum (ER) stress and cell death. Additionally, eicosanoids from COX and LOX also have important roles in some of the myocardial diseases, such as cardiac hypertrophy and ischemic heart disease. This chapter summarizes the physiological and pathophysiological significance, and the signal mechanisms of the eicosanoids, especially the EETs, in myocardial diseases.

Vasospastic angina: Past, present, and future.

Vasospastic angina (VSA) is characterized by episodes of rest angina that are responsive to short-acting nitrates and are attributable to coronary artery vasospasm. The condition is underdiagnosed as the provocation test is rarely performed. VSA, the most important component of non-obstructive coronary artery disease, can present with angina, be asymptomatic, or can even present with fatal arrhythmias and cardiac arrest. Although most patients with VSA respond well to vasodilating medications, prognosis does not improve as expected in most patients, suggesting the existence elusive prognostic factors and pathogenesis that warrant further exploration. Moreover, patients with either severe or refractory VSA barely respond to conventional treatment and may develop life-threatening arrhythmias or suffer sudden cardiac death during ischemic attacks, which are associated with immune-inflammatory responses and have been shown to achieve remission following glucocorticoid and immunoglobulin treatments. Our recent work revealed that inflammation plays a key role in the initiation and development of coronary spasms, and that inflammatory cytokines have predictive value for diagnosis. In contrast to the existing literature, this review both summarizes the theoretical and clinical aspects of VSA, and also discusses the relationship between inflammation, especially myocarditis and VSA, in order to provide novel insights into the etiology, diagnosis, and treatment of VSA.

Epoxyeicosatrienoic acid: A potential therapeutic target of heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) reduces the quality of life, costs substantial medical resources, and has a high mortality. However, we lack an effective therapy for HFpEF due to our limited knowledge of its mechanism. Therefore, it is crucial to explore novel therapeutics, such as those with endogenous protective roles, and seek new targeted therapies. Epoxyeicosatrienoic acids (EETs) are endogenous bioactive metabolites of arachidonic acids produced by cytochrome P450 (CYP) epoxygenases. EETs can function as endogenous cardioprotective factors with potent inhibitory roles in inflammation, endothelial dysfunction, cardiac remodeling, and fibrosis, which are the fundamental mechanisms of HFpEF. This suggests that EETs have the potential function to protect against HFpEF. Therefore, we present an overview of the ever-expanding world of EETs and how they might help alleviate the pathophysiology underlying HFpEF to provide new insights for research in this field.

Chlorpromazine Efficiently Treats the Crisis of Pheochromocytoma: Four Case Reports and Literature Review.

Pheochromocytoma multisystem crisis (PMC) is a potentially lethal emergency due to catecholamine secretion. The condition manifests as severe hypertension to intractable cardiogenic shock and has a high mortality rate. This study explored the efficacy and safety of applying chlorpromazine on PMC patients. The study included seven patients (median age, 42 years; range, 14-57 years) diagnosed with pheochromocytoma. Four consecutive PMC patients were admitted to our critical care unit between 2016 and 2020 due to abdominal or waist pain, nausea, and vomiting. Their blood pressure (BP) fluctuated between 200-330/120-200 and 40-70/30-50 mmHg. Chlorpromazine (25 or 50 mg) was injected intramuscularly, followed by continuous intravenous infusion (2-8 mg/h). The patients' BP decreased to 100-150/60-100 mmHg within 1-3 h and stabilized within 3-5 days. Two weeks later, surgical tumor resection was successfully performed in all four patients. Similar clinical outcomes were also obtained in three patients with sporadic PMC reported in the literature who received chlorpromazine treatment, which reduced their BP readings from >200/100 mmHg to 120/70 mmHg. Our observations, combined with sporadic reports, showed that chlorpromazine efficiently controlled PMC. Thus, future studies on the use of chlorpromazine are warranted.

Single-case metanalysis of fat embolism syndrome.

BACKGROUND: Only one large series has been reported on fat embolism syndrome (FES), a condition caused by fat globules release into the circulation, primarily as consequence of bone fracture. Thus, more data on clinical features, therapies, and prognosis are needed. METHODS AND RESULTS: The study screened 1090 manuscripts in PubMed and Web of Science on cases of FES published from June 2010 to June 2020. The authors identified 124 studies and included in the pooled-analysis 135 patients (>14 years), plus one additional unpublished case managed in Tongji hospital. All had confirmed diagnosis of FES with complete clinical data. The median age at presentation was 39 years, and 82 (61.8%) were men. FES was predominantly associated with bone fractures (78, 57.4%), particularly femur fracture (59, 43.4%). The most common clinical finding at the onset was respiratory abnormalities in 34.6% of all clinical presentations. Therapies included respiratory supportive care in 127 (93.4%) patients, application of corticosteroids in 22 (16.2%) and anticoagulant in 5 (3.7%) cases. Overall mortality was 30.2% (N = 41), and logistic regression analysis showed that corticosteroid therapy was significantly associated with reduced mortality with an OR of 0.143 (95%CI 0.029-0.711), while age ≥ 65 years and non-orthopedic conditions were significantly associated with increased mortality with an OR of 4.816 (95%CI 1.638-14.160) and 4.785 (95%CI 1.019-22.474). CONCLUSIONS: FES has been associated with a larger mortality rate than previously observed, although publication bias can have led to overestimation of mortality. Finally, a potential protective effect of corticosteroid therapy has been suggested by the current analysis.

Adenosine 2A Receptor Activation Contributes to Ang II-Induced Aortic Remodeling by Promoting Macrophage Retention.

The A2AR (adenosine 2A receptor) plays a crucial role in the pathophysiological process of cardiovascular diseases, yet its effect on aortic remodeling remains unclear. We observed elevated adenosine and A2AR levels following infusion of mice with Ang II (angiotensin II), suggesting a potential role for the adenosine-A2AR system in macrophage accumulation and subsequent aortic remodeling. The effects and mechanisms of A2AR on macrophage dynamics during aortic remodeling were further investigated using mice with macrophage knockout of A2AR and by transplantation of A2AR-/- bone marrow. We demonstrated that macrophage knockout of A2AR inhibited macrophage accumulation and subsequent aortic remodeling by inhibiting macrophage retention. This was shown to occur via promotion of macrophage emigration to the draining lymph node. These effects correlated with restoration of the expression and surface content of CCR7 (CC chemokine receptor 7). Consistently, A2AR-/- bone marrow transplantation relieved Ang II-induced aortic remodeling, macrophage retention, and CCR7 downregulation and internalization, all of which were rescued by A2AR+/+ bone marrow transplantation. In addition, CCR7 antibody treatment blocked all the protective effects observed in A2AR-cKO mice, including attenuation of aortic remodeling and decreased macrophage retention. In in vitro studies, A2AR activation induced by Ang II suppressed macrophage migration to CCL19 (CC-chemokine ligand) 19 through downregulation and internalization of CCR7. In summary, A2AR activation contributes to Ang II-induced macrophage retention and subsequent aortic remodeling by inhibiting migration of macrophages to the draining lymph node through regulating CCR7 expression and internalization.

Trimetazidine Inhibits Renal Tubular Epithelial Cells to Mesenchymal Transition in Diabetic Rats via Upregulation of Sirt1.

Trimetazidine (TMZ), as a metabolic regulator, is effective in treatment of coronary atherosclerotic heart disease with rare side effects in the clinic for long years. Interestingly, studies have shown that TMZ protects against several acute kidney injuries (AKI). However, the effect of TMZ on chronic kidney diseases (CKD) remains unknown. This study aimed to investigate the role of TMZ in diabetic nephropathy (DN) and its potential mechanisms. A rat model of DN was established in male Sprague-Dawley rats by streptozotocin (STZ) intraperitoneal injection. Experimental rats were separated into three groups: control, DN and DN + TMZ treatment. Metabolic parameters, pathological features and renal function markers were evaluated after 20 weeks of diabetes induction. In vitro experiments, the effect of TMZ on high fat and high glucose (HFG) induced or TGFß1-induced epithelial-to-mesenchymal transition (EMT) was examined in HK-2 cells. Our results showed that TMZ could maintain renal function without affecting hemodynamic and plasma metabolic levels in diabetic rats. The effect was associated with a reversion of pathological progression of DN, especially for tubulointerstitial fibrosis. EMT is an important contributor to renal fibrosis. In this study, we investigated the role of TMZ in the process of EMT in DN. Mechanistically; TMZ attenuated HFG-induced EMT by relieving oxidative stress via deacetylation forkhead box O1 (FoxO1) in a Sirt1-dependent pathway. And it suppressed TGFß1-induced EMT by deacetylating Smd4 in a Sirt1-dependent manner. Moreover, our study found that TMZ upregulated Sirt1 expression by increasing the expression of nicotinamide phosphoribosyl transferase (Nampt), which is a rate limiting enzyme for nicotinamide adenine dinucleotide (NAD+) generation by salvage pathway. And the increased NAD+ promoted Sirt1 expression. In conclusion, TMZ can prevent renal dysfunction and pathogenesis of tubulointerstitial fibrosis in DN, partly by inhibition of EMT via FoxO1/ROS pathway and TGFß/Smad pathway in a Nampt/NAD+/Sirt1 dependent manner.

Cardiomyocyte-specific expression of CYP2J2 prevents development of cardiac remodelling induced by angiotensin II.

AIMS: Cardiac remodelling is one of the key pathological changes that occur with cardiovascular disease. Previous studies have demonstrated the beneficial effects of CYP2J2 expression on cardiac injury. In the present study, we investigated the effects of cardiomyocyte-specific CYP2J2 expression and EET treatment on angiotensin II-induced cardiac remodelling and sought to determine the underlying molecular mechanisms involved in this process. METHODS AND RESULTS: Eight-week-old mice with cardiomyocyte-specific CYP2J2 expression (αMHC-CYP2J2-Tr) and wild-type (WT) control mice were treated with Ang-II. Ang-II treatment of WT mice induced changes in heart morphology, cardiac hypertrophy and dysfunction, as well as collagen accumulation; however, cardiomyocyte-specific expression of CYP2J2 attenuated these effects. The cardioprotective effects observed in α-MHC-CYP2J2-Tr mice were associated with peroxisome proliferator-activated receptor (PPAR)-γ activation, reduced oxidative stress, reduced NF-κB p65 nuclear translocation, and inhibition of TGF-ß1/smad pathway. The effects seen with cardiomyocyte-specific expression of CYP2J2 were partially blocked by treatment with PPAR-γ antagonist GW9662. In in vitro studies, 11,12-EET(1 µmol/L) treatment attenuated cardiomyocyte hypertrophy and remodelling-related protein (collagen I, TGF-ß1, TIMP1) expression by inhibiting the oxidative stress-mediated NF-κB pathway via PPAR-γ activation. Furthermore, conditioned media from neonatal cardiomyocytes treated with 11,12-EET inhibited activation of cardiac fibroblasts and TGF-ß1/smad pathway. CONCLUSION: Cardiomyocyte-specific expression of CYP2J2 or treatment with EETs protects against cardiac remodelling by attenuating oxidative stress-mediated NF-κBp65 nuclear translocation via PPAR-γ activation.