Specific NLRP3 Inhibition Protects Against Diabetes-Associated Atherosclerosis.

Low-grade persistent inflammation is a feature of diabetes-driven vascular complications, in particular activation of the Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome to trigger the maturation and release of the inflammatory cytokine interleukin-1ß (IL-1ß). We investigated whether inhibiting the NLRP3 inflammasome, through the use of the specific small-molecule NLRP3 inhibitor MCC950, could reduce inflammation, improve vascular function, and protect against diabetes-associated atherosclerosis in the streptozotocin-induced diabetic apolipoprotein E-knockout mouse. Diabetes led to an approximately fourfold increase in atherosclerotic lesions throughout the aorta, which were significantly attenuated with MCC950 (P < 0.001). This reduction in lesions was associated with decreased monocyte-macrophage content, reduced necrotic core, attenuated inflammatory gene expression (IL-1ß, tumor necrosis factor-α, intracellular adhesion molecule 1, and MCP-1; P < 0.05), and reduced oxidative stress, while maintaining fibrous cap thickness. Additionally, vascular function was improved in diabetic vessels of mice treated with MCC950 (P < 0.05). In a range of cell lines (murine bone marrow-derived macrophages, human monocytic THP-1 cells, phorbol 12-myristate 13-acetate-differentiated human macrophages, and aortic smooth muscle cells from humans with diabetes), MCC950 significantly reduced IL-1ß and/or caspase-1 secretion and attenuated leukocyte-smooth muscle cell interactions under high glucose or lipopolysaccharide conditions. In summary, MCC950 reduces plaque development, promotes plaque stability, and improves vascular function, suggesting that targeting NLRP3-mediated inflammation is a novel therapeutic strategy to improve diabetes-associated vascular disease.

Serum Amyloid A Stimulates Vascular and Renal Dysfunction in Apolipoprotein E-Deficient Mice Fed a Normal Chow Diet.

Elevated serum amyloid A (SAA) levels may promote endothelial dysfunction, which is linked to cardiovascular and renal pathologies. We investigated the effect of SAA on vascular and renal function in apolipoprotein E-deficient (ApoE-/-) mice. Male ApoE-/- mice received vehicle (control), low-level lipopolysaccharide (LPS), or recombinant human SAA by i.p. injection every third day for 2 weeks. Heart, aorta and kidney were harvested between 3 days and 18 weeks after treatment. SAA administration increased vascular cell adhesion molecule (VCAM)-1 expression and circulating monocyte chemotactic protein (MCP)-1 and decreased aortic cyclic guanosine monophosphate (cGMP), consistent with SAA inhibiting nitric oxide bioactivity. In addition, binding of labeled leukocytes to excised aorta increased as monitored using an ex vivo leukocyte adhesion assay. Renal injury was evident 4 weeks after commencement of SAA treatment, manifesting as increased plasma urea, urinary protein, oxidized lipids, urinary kidney injury molecule (KIM)-1 and multiple cytokines and chemokines in kidney tissue, relative to controls. Phosphorylation of nuclear-factor-kappa-beta (NFκB-p-P65), tissue factor (TF), and macrophage recruitment increased in kidneys from ApoE-/- mice 4 weeks after SAA treatment, confirming that SAA elicited a pro-inflammatory and pro-thrombotic phenotype. These data indicate that SAA impairs endothelial and renal function in ApoE-/- mice in the absence of a high-fat diet.

A novel synthetic small molecule DMFO targets Nrf2 in modulating proinflammatory/antioxidant mediators to ameliorate inflammation.

Inflammation is a protective immune response against invading pathogens, however, dysregulated inflammation is detrimental. As the complex inflammatory response involves multiple mediators, including the involvement of reactive oxygen species, concomitantly targeting proinflammatory and antioxidant check-points may be a more rational strategy. We report the synthesis and anti-inflammatory/antioxidant activity of a novel indanedione derivative DMFO. DMFO scavenged reactive oxygen species (ROS) in in-vitro radical scavenging assays and in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. In acute models of inflammation (carrageenan-induced inflammation in rat paw and air pouch), DMFO effectively reduced paw oedema and leucocyte infiltration with an activity comparable to diclofenac. DMFO stabilised mast cells (MCs) in in-vitro A23187 and compound 48/80-induced assays. Additionally, DMFO stabilised MCs in an antigen (ovalbumin)-induced MC degranulation model in-vivo, without affecting serum IgE levels. In a model of chronic immune-mediated inflammation, Freund's adjuvant-induced arthritis, DMFO reduced arthritic score and contralateral paw oedema, and increased the pain threshold with an efficacy comparable to diclofenac but without being ulcerogenic. Additionally, DMFO significantly reduced serum TNFα levels. Mechanistic studies revealed that DMFO reduced proinflammatory genes (IL1ß, TNFα, IL6) and protein levels (COX2, MCP1), with a concurrent increase in antioxidant genes (NQO1, haem oxygenase 1 (HO-1), Glo1, Nrf2) and protein (HO-1) in LPS-stimulated macrophages. Importantly, the anti-inflammatory/antioxidant effect on gene expression was absent in primary macrophages isolated from Nrf2 KO mice suggesting an Nrf2-targeted activity, which was subsequently confirmed using siRNA transfection studies in RAW macrophages. Therefore, DMFO is a novel, orally-active, safe (even at 2 g/kg p.o.), a small molecule which targets Nrf2 in ameliorating inflammation.

Nrf2 Activation Is a Potential Therapeutic Approach to Attenuate Diabetic Retinopathy.

Purpose: Oxidative stress is a causal factor in the development of diabetic retinopathy; however, clinically relevant strategies to treat the disease by augmenting antioxidant defense mechanisms have not been fully explored. We hypothesized that boosting nuclear factor erythroid-2-related factor 2 (Nrf2) antioxidant capacity with the novel Nrf2 activator dh404, would protect the retina in diabetes including vision-threatening breakdown of the blood-retinal barrier (BRB) and associated damage to macroglial Müller cells. Methods: Sprague-Dawley rats were randomized to become diabetic or nondiabetic and administered dh404 by gavage for 10 weeks. Complementary in vitro studies were performed in cultured Müller cells exposed to hyperglycemia. Results: In diabetes, dh404 prevented vascular leakage into the retina and vitreous cavity as well as upregulation of the vascular permeability and angiogenic factors, VEGF, and angiopoietin-2, and inflammatory mediators, including TNF-α and IL-6. Müller cells, which maintain BRB integrity and become gliotic in diabetes with increased immunolabeling for glial fibrillary acidic protein, were protected by dh404. In diabetes, dh404 bolstered the antioxidant capacity of the retina with an increase in hemeoxygenase-1, nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NADH/NADPH) quinine oxidoreductase-1, and Nrf2. Further, dh404 attenuated the diabetes-induced increase in oxidative stress as measured by dihydroethidium and 8-oxo-2'-deoxyguanosine (8-OHdG) immunolabeling as well as NADPH oxidase isoform expression. Studies in Müller cells supported these findings with dh404 attenuating the hyperglycemia-induced increase in vascular permeability, angiogenic and inflammatory mediators, and oxidative stress. Conclusions: Our data demonstrate the ability of dh404 to protect the retina against diabetes-induced damage and potentially prevent vision loss.

NFκB Inhibition Mitigates Serum Amyloid A-Induced Pro-Atherogenic Responses in Endothelial Cells and Leukocyte Adhesion and Adverse Changes to Endothelium Function in Isolated Aorta.

The acute phase protein serum amyloid A (SAA) is associated with endothelial dysfunction and early-stage atherogenesis. Stimulation of vascular cells with SAA increases gene expression of pro-inflammation cytokines and tissue factor (TF). Activation of the transcription factor, nuclear factor kappa-B (NFκB), may be central to SAA-mediated endothelial cell inflammation, dysfunction and pro-thrombotic responses, while targeting NFκB with a pharmacologic inhibitor, BAY11-7082, may mitigate SAA activity. Human carotid artery endothelial cells (HCtAEC) were pre-incubated (1.5 h) with 10 µM BAY11-7082 or vehicle (control) followed by SAA (10 µg/mL; 4.5 h). Under these conditions gene expression for TF and Tumor Necrosis Factor (TNF) increased in SAA-treated HCtAEC and pre-treatment with BAY11-7082 significantly (TNF) and marginally (TF) reduced mRNA expression. Intracellular TNF and interleukin 6 (IL-6) protein also increased in HCtAEC supplemented with SAA and this expression was inhibited by BAY11-7082. Supplemented BAY11-7082 also significantly decreased SAA-mediated leukocyte adhesion to apolipoprotein E-deficient mouse aorta in ex vivo vascular flow studies. In vascular function studies, isolated aortic rings pre-treated with BAY11-7082 prior to incubation with SAA showed improved endothelium-dependent vasorelaxation and increased vascular cyclic guanosine monophosphate (cGMP) content. Together these data suggest that inhibition of NFκB activation may protect endothelial function by inhibiting the pro-inflammatory and pro-thrombotic activities of SAA.

Does lack of glutathione peroxidase 1 gene expression exacerbate lung injury induced by neonatal hyperoxia in mice?

Supplemental oxygen (O2) increases the risk of lung injury in preterm infants, owing to an immature antioxidant system. Our objective was to determine whether impairing antioxidant defense by decreasing glutathione peroxidase 1 (GPx1) gene expression increases the injurious effects of hyperoxia (Hyp). GPx1+/+ and GPx1-/- C57Bl/6J mice were exposed to 21% O2 (Air) or 40% O2 (Hyp) from birth to postnatal day 7 (P7d); they were euthanized on P7d or maintained in air until adulthood [postnatal day 56 (P56d)] to assess short-term and long-term effects, respectively. We assessed lung architecture, three markers of pulmonary oxidative stress (P7d, P56d), macrophages in lung tissue (P7d), immune cells in bronchoalveolar lavage fluid (BALF; P56d), and GPx1-4 and catalase gene expression in lung tissue (P7d, P56d). On P7d, macrophages were decreased by lack of GPx1 expression and further decreased by hyperoxia. GPx1 expression was increased in GPx1+/+Hyp mice and decreased in both GPx1-/- groups. On P56d, heme oxygenase-1 was increased by hyperoxia when GPx1 was absent. There were significantly more immune cells from Hyp groups than from the GPx1+/+Air group and a greater proportion of lymphocytes in GPx1-/-Hyp mice. GPx1 expression was significantly decreased in GPx1-/- mice; GPx2-4 and catalase expression was increased in GPx1-/-Hyp mice compared with other groups. Tissue fraction was decreased in GPx1-/-Air mice; bronchiolar smooth muscle was decreased in GPx1-/- mice. GPx1 does not clearly exacerbate hyperoxia-induced increases in oxidative stress or lung injury but may alter pulmonary immune function. Increased expression of GPx2-4 and catalase in GPx1-/-Hyp mice suggests gene redundancy within the model.

A potent Nrf2 activator, dh404, bolsters antioxidant capacity in glial cells and attenuates ischaemic retinopathy.

An imbalance in oxidative stress and antioxidant defense mechanisms contributes to the development of ischaemic retinopathies such as diabetic retinopathy and retinopathy of prematurity (ROP). Currently, the therapeutic utility of targeting key transcription factors to restore this imbalance remains to be determined. We postulated that dh404, an activator of nuclear factor erythroid-2 related factor 2 (Nrf2), the master regulator of oxidative stress responses, would attenuate retinal vasculopathy by mechanisms involving protection against oxidative stress-mediated damage to glia. Oxygen-induced retinopathy (OIR) was induced in neonatal C57BL/6J mice by exposure to hyperoxia (phase I) followed by room air (phase II). dh404 (1 mg/kg/every second day) reduced the vaso-obliteration of phase I OIR and neovascularization, vascular leakage and inflammation of phase II OIR. In phase I, the astrocytic template and vascular endothelial growth factor (VEGF) expression necessary for physiological angiogenesis are compromised resulting in vaso-obliteration. These events were attenuated by dh404 and related to dh404's ability to reduce the hyperoxia-induced increase in reactive oxygen species (ROS) and markers of cell damage as well as boost the Nrf2-responsive antioxidants in cultured astrocytes. In phase II, neovascularization and vascular leakage occurs following gliosis of Müller cells and their subsequent increased production of angiogenic factors. dh404 reduced Müller cell gliosis and vascular leakage in OIR as well as the hypoxia-induced increase in ROS and angiogenic factors with a concomitant increase in Nrf2-responsive antioxidants in cultured Müller cells. In conclusion, agents such as dh404 that reduce oxidative stress and promote antioxidant capacity offer a novel approach to lessen the vascular and glial cell damage that occurs in ischaemic retinopathies.

Are reactive oxygen species still the basis for diabetic complications?

Despite the wealth of pre-clinical support for a role for reactive oxygen and nitrogen species (ROS/RNS) in the aetiology of diabetic complications, enthusiasm for antioxidant therapeutic approaches has been dampened by less favourable outcomes in large clinical trials. This has necessitated a re-evaluation of pre-clinical evidence and a more rational approach to antioxidant therapy. The present review considers current evidence, from both pre-clinical and clinical studies, to address the benefits of antioxidant therapy. The main focus of the present review is on the effects of direct targeting of ROS-producing enzymes, the bolstering of antioxidant defences and mechanisms to improve nitric oxide availability. Current evidence suggests that a more nuanced approach to antioxidant therapy is more likely to yield positive reductions in end-organ injury, with considerations required for the types of ROS/RNS involved, the timing and dosage of antioxidant therapy, and the selective targeting of cell populations. This is likely to influence future strategies to lessen the burden of diabetic complications such as diabetes-associated atherosclerosis, diabetic nephropathy and diabetic retinopathy.

Ebselen by modulating oxidative stress improves hypoxia-induced macroglial Müller cell and vascular injury in the retina.

Oxidative stress is an important contributor to glial and vascular cell damage in ischemic retinopathies. We hypothesized that ebselen via its ability to reduce reactive oxygen species (ROS) and augment nuclear factor-like 2 (Nrf2) anti-oxidants would attenuate hypoxia-induced damage to macroglial Müller cells and also lessen retinal vasculopathy. Primary cultures of rat Müller cells were exposed to normoxia (21% O2), hypoxia (0.5% O2) and ebselen (2.5 µM) for up to 72 h. Oxygen-induced retinopathy (OIR) was induced in C57BL/6J mice while control mice were housed in room air. Mice received vehicle (saline, 5% dimethyl sulfoxide) or ebselen (10 mg/kg) each day between postnatal days 6-18. In cultured Müller cells, flow cytometry for dihydroethidium revealed that ebselen reduced the hypoxia-induced increase in ROS levels, whilst increasing the expression of Nrf2-regulated anti-oxidant genes, heme oxygenase 1, glutathione peroxidase-1, NAD(P)H dehydrogenase quinone oxidoreductase 1 and glutamate-cysteine ligase. Moreover, in Müller cells, ebselen reduced the hypoxia-induced increase in protein levels of pro-angiogenic and pro-inflammatory factors including vascular endothelial growth factor, interleukin-6, monocyte chemoattractant-protein 1 and intercellular adhesion molecule-1, and the mRNA levels of glial fibrillary acidic protein (GFAP), a marker of Müller cell injury. Ebselen improved OIR by attenuating capillary vaso-obliteration and neovascularization and a concomitant reduction in Müller cell gliosis and GFAP. We conclude that ebselen protects against hypoxia-induced injury of retinal Müller cells and the microvasculature, which is linked to its ability to reduce oxidative stress, vascular damaging factors and inflammation. Agents such as ebselen may be potential treatments for retinopathies that feature oxidative stress-mediated damage to glia and the microvasculature.

Limiting reductive stress for treating in-stent stenosis: the heart of the matter?

Restenosis after balloon angioplasty and stenting (BAS) remains an unsolved clinical dilemma for patients with coronary artery disease. A better understanding of the mechanisms that drive this phenomenon is likely to lead to more effective treatments. In this issue of the JCI, Ali et al. uncover a critical redox axis with the antioxidant enzyme glutathione peroxidase-1 (GPX1) at its hub and identify potential new therapeutic targets, such as ROS1 tyrosine kinase. This study represents a potential new approach to finding a treatment for BAS, with implications that may extend beyond BAS to other vasculopathies involving vascular remodeling.

Derivative of bardoxolone methyl, dh404, in an inverse dose-dependent manner lessens diabetes-associated atherosclerosis and improves diabetic kidney disease.

Oxidative stress and inflammation are inextricably linked and play essential roles in the initiation and progression of diabetes complications such as diabetes-associated atherosclerosis and nephropathy. Bolstering antioxidant defenses is an important mechanism to lessen oxidative stress and inflammation. In this study, we have used a novel analog of the NFE2-related factor 2 (Nrf2) agonist bardoxolone methyl, dh404, to investigate its effects on diabetic macrovascular and renal injury in streptozotocin-induced diabetic apolipoprotein E(-/-) mice. We show that dh404, at lower but not higher doses, significantly lessens diabetes-associated atherosclerosis with reductions in oxidative stress (in plasma, urine, and vascular tissue) and proinflammatory mediators tumor necrosis factor-α, intracellular adhesion molecule-1, vascular cell adhesion molecule-1, and monocyte chemotactic protein-1 (MCP-1). We demonstrate that dh404 attenuates functional (urinary albumin-to-creatinine ratio) and structural (mesangial expansion) glomerular injury and improves renal tubular injury. Liver functional and structural studies showed that dh404 is well tolerated. Complementary in vitro studies in normal rat kidney cells showed that dh404 significantly upregulates Nrf2-responsive genes, heme oxygenase-1, NAD(P)H quinone oxidoreductase 1, and glutathione-S transferase, with inhibition of transforming growth factor-ß-mediated profibrotic fibronectin, collagen I, and proinflammatory interleukin-6. Higher doses of dh404 were associated with increased expression of proinflammatory mediators MCP-1 and nuclear factor-κB. These findings suggest that this class of compound is worthy of further study to lessen diabetes complications but that dosage needs consideration.

An apolipoprotein A-I mimetic peptide designed with a reductionist approach stimulates reverse cholesterol transport and reduces atherosclerosis in mice.

Apolipoprotein A-I (apoA-I) mimetic peptides are considered a promising novel therapeutic approach to prevent and/or treat atherosclerosis. An apoA-I mimetic peptide ELK-2A2K2E was designed with a reductionist approach and has shown exceptional activity in supporting cholesterol efflux but modest anti-inflammatory and anti-oxidant properties in vitro. In this study we compared these in vitro properties with the capacity of this peptide to modify rates of reverse cholesterol transport and development of atherosclerosis in mouse models. The peptide enhanced the rate of reverse cholesterol transport in C57BL/6 mice and reduced atherosclerosis in Apoe(-/-) mice receiving a high fat diet. The peptide modestly reduced the size of the plaques in aortic arch, but was highly active in reducing vascular inflammation and oxidation. Administration of the peptide to Apoe(-/-) mice on a high fat diet reduced the levels of total, high density lipoprotein and non-high density lipoprotein cholesterol and triglycerides. It increased the proportion of smaller HDL particles in plasma at the expense of larger HDL particles, and increased the capacity of the plasma to support cholesterol efflux. Thus, ELK-2A2K2E peptide reduced atherosclerosis in Apoe(-/-) mice, however, the functional activity profile after chronic in vivo administration was different from that found in acute in vitro studies.

Targeted antioxidant therapies in hyperglycemia-mediated endothelial dysfunction.

Although intensive glycaemic and blood pressure control have reduced the risks of micro- and macrovascular complications, diabetes remains a major cause of cardiovascular events, end-stage renal failure, blindness and neuropathy. It is therefore imperative to understand the underlying mechanisms and to establish effective treatments to prevent, retard or reverse diabetic complications. One area of increased focus is the diabetic vascular endothelium. Hyperglycaemia triggers a cascade of events, not least an increase in reactive oxygen species (ROS) leading to enhanced oxidative stress, with its negative impact on endothelial function. In this review, we explore a unifying hypothesis that increased glucose-mediated ROS leads to endothelial dysfunction as the underpinning causative event triggering accelerated micro- and macrovascular complications. In particular, the consequences of deficiencies in the antioxidant enzyme, glutathione peroxidase, on endothelial dysfunction as a trigger of diabetic micro- and macrovascular complications, will be reviewed. Furthermore, novel antioxidant therapies will be highlighted. Specifically, use of Gpx1-mimetics holds promise as a targeted antioxidant approach and an alternative adjunct therapy to reduce diabetic complications.

Site-specific antiatherogenic effect of the antioxidant ebselen in the diabetic apolipoprotein E-deficient mouse.

OBJECTIVE: Recently we showed that lack of the antioxidant enzyme glutathione peroxidase-1 (GPx1) accelerates atherosclerosis and upregulates proatherogenic pathways in diabetic apoE/GPx1-deficient double-knockout mice, thereby establishing GPx1 as an important therapeutic target. In vivo studies now investigate ebselen, a seleno-organic GPx1-mimetic, for its potential to reduce diabetes-associated atherosclerosis. METHODS AND RESULTS: Lesions were significantly increased in diabetic apoE(-/-) aortas (P<0.001) compared with nondiabetic controls after 20 weeks of diabetes. Ebselen-gavage significantly reduced total aortic lesions (P<0.001), with significant regional reductions in the arch (P<0.001), thoracic (P<0.001), and abdominal regions (P<0.05), but not within the aortic sinus of diabetic apoE(-/-) mice. These reductions were accompanied by significantly lower nitrotyrosine and Nox2 levels, reduced proatherogenic cellularity (macrophages and SMCs), and reduced expression of the proatherogenic mediator RAGE. Within the aortic sinus, ebselen reduced nitrotyrosine, Nox2, and VEGF levels but had no effect on RAGE. Studies in HAECs show that ebselen abrogates H(2)O(2)-induced increases in P-IKK, P-JNK, TNF-alpha, and Nox2. CONCLUSIONS: Ebselen reduces atherosclerotic lesions in most regions of diabetic apoE(-/-) aorta, except within the aortic sinus, suggesting its effectiveness as a potential antiatherogenic therapy in diabetic-macrovascular disease. Ebselen may elicit its effect via modulation of transcription factors such as NF-kappaB and AP-1.

Lack of the antioxidant enzyme glutathione peroxidase-1 accelerates atherosclerosis in diabetic apolipoprotein E-deficient mice.

BACKGROUND: Recent clinical studies have suggested a major protective role for the antioxidant enzyme glutathione peroxidase-1 (GPx1) in diabetes-associated atherosclerosis. We induced diabetes in mice deficient for both GPx1 and apolipoprotein E (ApoE) to determine whether this is merely an association or whether GPx1 has a direct effect on diabetes-associated atherosclerosis. METHODS AND RESULTS: ApoE-deficient (ApoE-/-) and ApoE/GPx1 double-knockout (ApoE-/- GPx1-/-) mice were made diabetic with streptozotocin and aortic lesion formation, and atherogenic pathways were assessed after 10 and 20 weeks of diabetes. Aortic proinflammatory and profibrotic markers were determined by both quantitative reverse-transcription polymerase chain reaction analysis after 10 weeks of diabetes and immunohistochemical analysis after 10 and 20 weeks of diabetes. Sham-injected nondiabetic counterparts served as controls. Atherosclerotic lesions within the aortic sinus region, as well as arch, thoracic, and abdominal lesions, were significantly increased in diabetic ApoE-/- GPx1-/- aortas compared with diabetic ApoE-/- aortas. This increase was accompanied by increased macrophages, alpha-smooth muscle actin, receptors for advanced glycation end products, and various proinflammatory (vascular cell adhesion molecule-1) and profibrotic (vascular endothelial growth factor and connective tissue growth factor) markers. Quantitative reverse-transcription polymerase chain reaction analysis showed increased expression of receptors for advanced glycation end products (RAGE), vascular cell adhesion molecule-1, vascular endothelial growth factor, and connective tissue growth factor. Nitrotyrosine levels were significantly increased in diabetic ApoE-/- GPx1-/- mouse aortas. These findings were observed despite upregulation of other antioxidants. CONCLUSIONS: Lack of functional GPx1 accelerates diabetes-associated atherosclerosis via upregulation of proinflammatory and profibrotic pathways in ApoE-/- mice. Our study provides evidence of a protective role for GPx1 and establishes GPx1 as an important antiatherogenic therapeutic target in patients with or at risk of diabetic macrovascular disease.

Lack of the antioxidant glutathione peroxidase-1 does not increase atherosclerosis in C57BL/J6 mice fed a high-fat diet.

Oxidative stress is thought to contribute to the initiation and progression of atherosclerosis. As glutathione peroxidase-1 (Gpx1) is an antioxidant enzyme that detoxifies lipid hydroperoxides, we tested the impact of Gpx1 deficiency on atherosclerotic processes and antioxidant enzyme expression in mice fed a high-fat diet (HFD). After 12 weeks of HFD, atherosclerotic lesions at the aortic sinus were of similar size in control and Gpx1-deficient mice. However, after 20 weeks of HFD, lesion size increased further in control but not in Gpx1-deficient mice, even though plasma and aortic wall markers of oxidative damage did not differ between groups. In control mice, the expression of Gpx1 increased and that of Gpx3 decreased at the aortic sinus after 20 weeks of HFD, with no change in the expression of Gpx2, Gpx4, catalase, peroxiredoxin-6, glutaredoxin-1 and -2, or thioredoxin-1 and -2. By comparison, in Gpx1-deficient mice, the expression of antioxidant genes was unaltered except for a decrease in glutaredoxin-1 and an increase in glutaredoxin-2. These changes were associated with increased expression of the proinflammatory marker monocyte chemoattractant protein-1 in control mice but not in Gpx1-deficient mice. In summary, a specific deficiency in Gpx1 was not accompanied by an increase in markers of oxidative damage or increased atherosclerosis in a murine model of HFD-induced atherogenesis.