Background
The major concern in patients who have suffered from cardiac arrest (CA) and undergone successful extracorporeal cardiopulmonary resuscitation (E‐CPR) is poor neurological outcomes. In ...this study, we aimed to introduce a rat model of selective brain perfusion (SBP) during E‐CPR to improve the neurological outcome after CA.
Methods
The rats underwent 7 min of untreated asphyxial CA and then were resuscitated with E‐CPR for 30 min. The right external jugular vein and right femoral artery were separately cannulated to the E‐CPR outflow and inflow. The right common carotid artery was cannulated from the proximal to the distal side for SBP. Subsequently, rats were removed from E‐CPR, wounds were closed, and 90 min of intensive care were provided. Neurological deficit scores were tested after 4 h of recovery when the rats were mechanical ventilation‐free. S100 calcium‐binding protein B (S100B) and glial fibrillary acidic protein (GFAP) were detected through immunohistochemistry (IHC) of brain tissue.
Results
The rats that received SBP while resuscitated by E‐CPR showed markedly better neurological performances after 4‐h recovery than those resuscitated by E‐CPR only. The IHC staining of GFAP and S100B in the hippocampus was low in the rats receiving SBP during E‐CPR, but only GFAP showed significant differences.
Conclusions
We successfully developed a novel and reproducible rat model of SBP while resuscitated by E‐CPR to ameliorate the neurological performances after CA. This achievement might have opportunities for studying how to improve the neurological outcome in the clinical condition.
Extracorporeal cardiopulmonary resuscitation with selective brain perfusion system in a rat model.
High-dose intravenous iron supplementation is associated with adverse cardiovascular outcomes in patients with CKD, but the underlying mechanism is unknown. Our study investigated the causative role ...of iron sucrose in leukocyte-endothelium interactions, an index of early atherogenesis, and subsequent atherosclerosis in the mouse remnant kidney model. We found that expression levels of intracellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and adhesion of U937 cells increased in iron-treated human aortic endothelial cells through upregulated NADPH oxidase (NOx) and NF-κB signaling. We then measured mononuclear-endothelial adhesion and atherosclerotic lesions of the proximal aorta in male C57BL/6 mice with subtotal nephrectomy, male apolipoprotein E-deficient (ApoE(-/-)) mice with uninephrectomy, and sham-operated mice subjected to saline or parenteral iron loading. Iron sucrose significantly increased tissue superoxide production, expression of tissue cell adhesion molecules, and endothelial adhesiveness in mice with subtotal nephrectomy. Moreover, iron sucrose exacerbated atherosclerosis in the aorta of ApoE(-/-) mice with uninephrectomy. In patients with CKD, intravenous iron sucrose increased circulating mononuclear superoxide production, expression of soluble adhesion molecules, and mononuclear-endothelial adhesion compared with healthy subjects or untreated patients. In summary, iron sucrose aggravated endothelial dysfunction through NOx/NF-κB/CAM signaling, increased mononuclear-endothelial adhesion, and exacerbated atherosclerosis in mice with remnant kidneys. These results suggest a novel causative role for therapeutic iron in cardiovascular complications in patients with CKD.
Soluble epoxide hydrolase (sEH) is a bifunctional enzyme with COOH-terminal hydrolase and NH2-terminal lipid phosphatase activities. It is expressed in various cell types in the brain and is involved ...in the pathogenesis of inflammatory and neurodegenerative diseases. Alzheimer's disease (AD) is a progressive neuroinflammatory and neurodegenerative disease. However, the pathological significance of sEH and underlying molecular mechanism in AD remain unclear.
To examine the role of sEH in pathogenesis of AD, we used wild-type (WT) mice, soluble epoxide hydrolase deficient (sEH
) and two mouse models of AD, including amyloid precursor protein (APP)/presenilin 1 (PS1) transgenic (APP/PS1 Tg) and APP/PS1 Tg/sEH
mice. Western blotting analysis and immunohistochemistry assay were performed to evaluate the protein expression. Locomotion, nesting building ability, Y-maze, and Morris water maze tests were conducted to study mouse behavior. The levels of interleukin (IL)-1β, IL-4, IL-6, and IL-10 and the activities of NF-κB and nuclear factor of activated T cells (NFAT) were measured by commercial assay kits. The quantitative protein level profiling in the brain lysate was analyzed using LC-MS/MS approaches.
We demonstrated that the level of sEH was increased in the brain and predominantly appeared in hippocampal astrocytes of APP/PS1 Tg mice. Genetic ablation of sEH in APP/PS1 Tg mice delayed the progression of AD as evidenced by the alleviation in behavior outcomes and Aβ plaque deposition. In addition, loss of the function of sEH in APP/PS1 Tg mice increased astrogliosis and the production of astrocyte-derived anti-inflammatory cytokines including IL-1β, IL-4, and IL-10, as well as the activity of NF-kB and NFAT. Moreover, analysis of gene ontology in the AD brain revealed that important signaling pathways and processes related to AD pathogenesis such as translational regulation, oxidative stress, cytoskeleton reorganization, and small GTPase signal transduction were altered in APP/PS1 Tg/sEH
mice compared with APP/PS1 Tg mice.
Our results suggest that sEH is a crucial regulator in the progression of AD and might be a potential therapeutic target for the treatment of AD.
Hyperuricemia is closely associated with the mobility and mortality of patients with cardiovascular diseases. However, how hyperuricemia accelerates atherosclerosis progression is not well ...understood. The balance between asymmetric dimethylarginine (ADMA) and dimethylarginine dimethylaminotransferases (DDAHs) is crucial to regulate vascular homeostasis. Therefore, we investigated the role of the ADMA/DDAH pathway in hyperuricemia-induced endothelial dysfunction and atherosclerosis and the underlying molecular mechanisms in endothelial cells (ECs) and apolipoprotein E–knockout (apoe−/−) mice. Our results demonstrated that uric acid at pathological concentrations increased the intracellular levels of ADMA and downregulated DDAH-2 expression without affecting DDAH-1 expression. Excess uric acid also reduced NO bioavailability and increased monocyte adhesion to ECs, which were abolished by using the antioxidant N-acetylcysteine, the nicotinamide adenine dinucleotide phosphate oxidase inhibitor apocynin, or DDAH-2 overexpression. In apoe−/− mice, treatment with oxonic acid, a uricase inhibitor, increased the circulating level of uric acid, cholesterol, and lipid peroxidation; exacerbated systemic and aortic inflammation; and worsened atherosclerosis compared with vehicle-treated apoe−/− mice. Furthermore, oxonic acid–treated apoe−/− mice exhibited elevated ADMA plasma level and downregulated aortic expression of DDAH-2 protein. Notably, DDAH-2 overexpression in the ECs of apoe−/− mice prevented hyperuricemia-induced deleterious effects from influencing ADMA production, lipid peroxidation, inflammation, and atherosclerosis. Collectively, our findings suggest that hyperuricemia disturbs the balance of the ADMA/DDAH-2 axis, results in EC dysfunction, and, consequently, accelerates atherosclerosis.
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•Excess uric acid decreases DDAH-2 expression and increases ADMA production in endothelial cells.•Excess uric acid induces endothelial dysfunction by activates the NOX/ROS signaling pathway.•DDAH-2 overexpression abrogates the detrimental effects of excess uric acid on endothelial function.•DDAH-2 overexpression in endothelial cells prevents hyperuricemia-induced oxidative stress, inflammation and atherosclerosis.
Aim
CCN family member 1 (CCN1) is an extracellular matrix cytokine and appears in atherosclerotic lesions. However, we have no evidence to support the role of CCN1 in regulating cholesterol ...metabolism and atherosclerosis.
Methods
Apolipoprotein E‐deficient (apoE−/−) mice were used as in vivo model. Oxidized low‐density lipoprotein (oxLDL)‐induced macrophage‐foam cells were used as in vitro model. RT‐PCR and western blot analysis were used for evaluating gene and protein expression, respectively. Conventional assay kits were used for assessing the levels of cholesterol, triglycerides, and cytokines.
Results
We show predominant expression of CCN1 in foamy macrophages in atherosclerotic aortas of apoE−/−mice. In apoE−/− mice, CCN1 treatment worsened hyperlipidaemia, systemic inflammation, and the progression of atherosclerosis. In addition, CCN1 decreased the capacity of reverse cholesterol transport and downregulated the protein expression of ATP‐binding cassette transporter A1 (ABCA1) and ABCG1 in atherosclerotic aortas. Notably, CCN1 decreased the protein expression of cholesterol clearance‐related proteins, including ABCG5, ABCG8, liver X receptor α (LXRα), cholesterol 7α‐hydrolase and LDL receptor in liver, and exacerbated hepatic lipid accumulation. In macrophages, treatment with oxLDL increased CCN1 expression. Inhibition of CCN1 activity by neutralizing antibody or small interfering RNA attenuated the oxLDL‐induced lipid accumulation. In contrast, cotreatment with CCN1 or overexpression of CCN1 augmented oxLDL‐induced lipid accumulation by impairing apolipoprotein AI‐ and high‐density lipoprotein‐dependent cholesterol efflux, which was attributed to downregulation of LXRα‐dependent expression of ABCA1 and ABCG1.
Conclusion
Our findings suggest that CCN1 plays a pivotal role in regulating cholesterol metabolism and the development of atherosclerosis.
Scope
Curcumin, a potent antioxidant extracted from Curcuma longa, confers protection against atherosclerosis, yet the detailed mechanisms are not fully understood. In this study, we examined the ...effect of curcumin on lipid accumulation and the underlying molecular mechanisms in macrophages and apolipoprotein E‐deficient (apoE−/−) mice.
Methods and results
Treatment with curcumin markedly ameliorated oxidized low‐density lipoprotein (oxLDL)‐induced cholesterol accumulation in macrophages, which was due to decreased oxLDL uptake and increased cholesterol efflux. In addition, curcumin decreased the protein expression of scavenger receptor class A (SR‐A) but increased that of ATP‐binding cassette transporter (ABC) A1 and had no effect on the protein expression of CD36, class B receptor type I (SR‐BI), or ATP‐binding cassette transporter G1 (ABCG1). The downregulation of SR‐A by curcumin was via ubiquitin–proteasome–calpain‐mediated proteolysis. Furthermore, the curcumin‐induced upregulation of ABCA1 was mainly through calmodulin‐liver X receptor α (LXRα)‐dependent transcriptional regulation. Curcumin administration modulated the expression of SR‐A, ABCA1, ABCG1, and SR‐BI in aortas and retarded atherosclerosis in apoE−/− mice.
Conclusion
Our findings suggest that inhibition of SR‐A‐mediated oxLDL uptake and promotion of ABCA1‐dependent cholesterol efflux are two crucial events in suppression of cholesterol accumulation by curcumin in the transformation of macrophage foam cells.
ATP-binding cassette transporter A1 (ABCA1) plays a crucial role in exporting cholesterol from macrophages, a function relevant to its involvement in the prevention of atherosclerosis. Quercetin, one ...of flavonoids, has been described to reduce atherosclerotic lesion formation. This study is aimed to investigate the effect of quercetin on regulation of ABCA1 expression and to explore its underlying mechanisms in macrophages. The results show that quercetin markedly enhanced cholesterol efflux from macrophages in a concentration-dependent manner, which was associated with an increase in ABCA1 mRNA and protein expression. Remarkably, quercetin is able to stimulate the phosphorylation of p38 by up to 234-fold at 6 h via an activation of the transforming growth factor β-activated kinase 1 (TAK1) and mitogen-activated kinase kinase 3/6 (MKK3/6). Inhibition of p38 with a pharmacological inhibitor or small hairpin RNA (shRNA) suppressed the stimulatory effects of quercetin on ABCA1 expression and cholesterol efflux. Moreover, knockdown of p38 reduced quercetin-enhanced ABCA1 promoter activity and the binding of specificity protein 1 (Sp1) and liver X receptor α (LXRα) to the ABCA1 promoter using chromatin immunoprecipitation assays. These findings provide evidence that p38 signaling is essential for the regulation of quercetin-induced ABCA1 expression and cholesterol efflux in macrophages.
Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A, are widely used to treat hypercholesterolemia. In addition, statins have been suggested to reduce the risk of cardiovascular events owing ...to their pleiotropic effects on the vascular system, including vasodilation, anti-inflammation, anti-coagulation, anti-oxidation, and inhibition of vascular smooth muscle cell proliferation. The major beneficial effect of statins in maintaining vascular homeostasis is the induction of nitric oxide (NO) bioavailability by activating endothelial NO synthase (eNOS) in endothelial cells. The mechanisms underlying the increased NO bioavailability and eNOS activation by statins have been well-established in various fields, including transcriptional and post-transcriptional regulation, kinase-dependent phosphorylation and protein-protein interactions. However, the mechanism by which statins affect the metabolism of L-arginine, a precursor of NO biosynthesis, has rarely been discussed. Autophagy, which is crucial for energy homeostasis, regulates endothelial functions, including NO production and angiogenesis, and is a potential therapeutic target for cardiovascular diseases. In this review, in addition to summarizing the molecular mechanisms underlying increased NO bioavailability and eNOS activation by statins, we also discuss the effects of statins on the metabolism of L-arginine.
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•The regulatory mechanisms of statins in the regulation of eNOS expression and eNOS activity.•The role of L-arginine metabolism in the statins-elicited NO bioavailability.•The potential therapeutic effects of statins on the treatment of vascular diseases.
Oxidative stress and inflammation play important roles in the pathophysiology of acute kidney injury (AKI). Transient receptor potential ankyrin 1 (TRPA1) is a Ca2+-permeable ion channel that is ...sensitive to reactive oxygen species (ROS). The role of TRPA1 in AKI remains unclear. In this study, we used human and animal studies to assess the role of renal TRPA1 in AKI and to explore the regulatory mechanism of renal TRPA1 in inflammation via in vitro experiments. TRPA1 expression increased in the renal tubular epithelia of patients with AKI. The severity of tubular injury correlated well with tubular TRPA1 or 8-hydroxy-2'-deoxyguanosine expression. In an animal model, renal ischemia-reperfusion injury (IR) increased tubular TRPA1 expression in wild-type (WT) mice.
mice displayed less IR-induced tubular injury, oxidative stress, inflammation, and dysfunction in kidneys compared with WT mice. In the in vitro model, TRPA1 expression increased in renal tubular cells under hypoxia-reoxygenation injury (H/R) conditions. We demonstrated that H/R evoked a ROS-dependent TRPA1 activation, which elevated intracellular Ca
level, increased NADPH oxidase activity, activated MAPK/NF-κB signaling, and increased IL-8. Renal tubular TRPA1 may serve as an oxidative stress sensor and a crucial regulator in the activation of signaling pathways and promote the subsequent transcriptional regulation of IL-8. These actions might be evident in mice with IR or patients with AKI.
Background/Aims: Olanzapine, an atypical antipsychotic drug, has therapeutic effects for schizophrenia. However, clinical reports indicate that patients taking atypical antipsychotic drugs are at ...high risk of metabolic syndrome with unclear mechanisms. We investigated the effect of olanzapine on atherosclerosis and the mechanisms in apolipoprotein E-null (apoE-/-) mice. Methods: ApoE-/- mice were used as in vivo models. Western blot analysis was used to evaluate protein expression. Conventional assay kits were applied to assess the levels of cholesterol, triglycerides, free cholesterol, cholesteryl ester, fatty acids, glycerol, and cytokines. Results: Daily treatment with olanzapine (3 mg/kg body weight) for four weeks increased mean arterial blood pressure and the whitening of brown adipose tissue in mice. In addition, olanzapine impaired aortic cholesterol homeostasis and exacerbated hyperlipidemia and aortic inflammation, which accelerated atherosclerosis in mice. Moreover, lipid accumulation in liver, particularly total cholesterol, free cholesterol, fatty acids, and glycerol, was increased with olanzapine treatment in apoE-/- mice by upregulating the expression of de novo lipid synthesis-related proteins and downregulating that of cholesterol clearance- or very low-density lipoprotein secretion-related proteins. Conclusion: Olanzapine may exacerbate atherosclerosis by deregulating hepatic lipid metabolism and worsening hyperlipidemia and aortic inflammation.
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