Legumain in cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, having become a global public health problem, so the pathophysiological mechanisms and therapeutic strategies of CVDs need further study. Legumain is a powerful enzyme that is widely distributed in mammals and plays an important role in a variety of biological processes. Recent research suggests that legumain is associated with the occurrence and progression of CVDs. In this review, we provide a comprehensive overview of legumain in the pathogenesis of CVDs. The role of legumain in CVDs, such as carotid atherosclerosis, pulmonary hypertension, coronary artery disease, peripheral arterial disease, aortic aneurysms and dissection, is discussed. The potential applications of legumain as a biomarker of these diseases are also explored. By understanding the role of legumain in the pathogenesis of CVDs, we aim to support new therapeutic strategies to prevent or treat these diseases.

Plasma legumain in familial hypercholesterolemia: associations with statin use and cardiovascular risk markers

Legumain is known to be regulated in atherosclerotic disease and may have both pro- and anti-atherogenic properties. The study aimed to explore legumain in individuals with familial hypercholesterolemia (FH), a population with increased cardiovascular risk. Plasma legumain was measured in 251 subjects with mostly genetically verified FH, of which 166 were adults (≥18 years) and 85 were children and young adults (<18 years) and compared to 96 normolipidemic healthy controls. Plasma legumain was significantly increased in the total FH population compared to controls (median 4.9 versus 3.3 pg/mL, respectively, p < 0.001), whereof adult subjects with FH using statins had higher levels compared to non-statin users (5.7 versus 3.9 pg/mL, respectively, p < 0.001). Children and young adults with FH (p = 0.67) did not have plasma legumain different from controls at the same age. Further, in FH subjects, legumain showed a positive association with apoB, and markers of inflammation and platelet activation (i.e. fibrinogen, NAP2 and RANTES). In the current study, we show that legumain is increased in adult subjects with FH using statins, whereas there was no difference in legumain among children and young adults with FH compared to controls. Legumain was further associated with cardiovascular risk markers in the FH population. However the role of legumain in regulation of cardiovascular risk in these individuals is still to be determined.

The Mammalian Cysteine Protease Legumain in Health and Disease

The cysteine protease legumain (also known as asparaginyl endopeptidase or δ-secretase) is the only known mammalian asparaginyl endopeptidase and is primarily localized to the endolysosomal system, although it is also found extracellularly as a secreted protein. Legumain is involved in the regulation of diverse biological processes and tissue homeostasis, and in the pathogenesis of various malignant and nonmalignant diseases. In addition to its proteolytic activity that leads to the degradation or activation of different substrates, legumain has also been shown to have a nonproteolytic ligase function. This review summarizes the current knowledge about legumain functions in health and disease, including kidney homeostasis, hematopoietic homeostasis, bone remodeling, cardiovascular and cerebrovascular diseases, fibrosis, aging and senescence, neurodegenerative diseases and cancer. In addition, this review addresses the effects of some marketed drugs on legumain. Expanding our knowledge on legumain will delineate the importance of this enzyme in regulating physiological processes and disease conditions.

High Plasma Levels of Legumain in Patients with Complex Coronary Lesions

Aim: The degradation of the vascular extracellular matrix is important for atherosclerosis. The cysteine protease legumain was shown to be upregulated in atherosclerotic plaques, especially unstable plaques. However, no study has reported blood legumain levels in patients with coronary artery disease (CAD).

Methods: We investigated plasma legumain and C-reactive protein (CRP) levels in 372 patients undergoing elective coronary angiography.

Results: CAD was found in 225 patients. Compared with patients without CAD, those with CAD had higher CRP levels (median 0.60 [0.32, 1.53] vs. 0.46 [0.22, 0.89] mg/L, P < 0.001), but no difference was found in legumain levels between patients with and without CAD (median 5.08 [3.87, 6.82] vs. 4.99 [3.84, 6.88] ng/mL). A stepwise increase in CRP was found depending on the number of > 50% stenotic vessels: 0.55 mg/L in 1-vessel, 0.71 mg/L in 2-vessel, and 0.86 mg/L in 3-vessel diseases (P < 0.001). However, legumain did not differ among 1-, 2-, and 3-vessel diseases (5.20, 4.93, and 5.01 ng/mL, respectively). Of 225 patients with CAD, 40 (18%) had complex lesions. No difference was found in CRP levels between patients with CAD with and without complex lesions (0.60 [0.34, 1.53] vs. 0.60 [0.32, 1.51] mg/L). Notably, legumain levels were higher in patients with CAD with complex lesions than without such lesions (6.05 [4.64, 8.64] vs. 4.93 [3.76, 6.52] ng/mL, P < 0.01). In multivariate analysis, legumain levels were not a factor for CAD, but were a factor for complex lesions. The odds ratio for complex lesions was 2.45 (95% CI = 1.26–4.79) for legumain > 5.5 ng/mL.

Conclusion: Plasma legumain levels were associated with the presence of complex coronary lesions.

Increased Legumain/Smad3 expression in atherosclerotic plaque of rat thoracic aorta

OBJECTIVES

The purpose of this study was to investigate the role of legumain in the formation and stability of atherosclerotic plaque, as well as to explore the association between legumain with Smad3 pathway in a rat atherosclerosis model.

METHODS

Rat with thoracic aorta atherosclerosis was established and received treatment with statin (n = 15 each) or controls (n = 10). Serum level of legumain was determined by enzyme-linked immunosorbent assay. Legumain and Smad3 aortic expression levels were assessed by immunohistochemistry and fluorescence microscopy. Protein and mRNA levels were analyzed using Western blot analysis and reverse transcriptase coupled polymerase chain reaction, respectively.

RESULTS

The atherosclerotic group showed higher serum legumain level than control and statin group. Expression of legumain and Smad3 in macrophages and foam cells was increased in atherosclerotic group compared to control and statin group. The protein and mRNA levels of legumain and Smad3 were significantly attenuated by statin treatment (p < 0.05). For all groups, legumain expression was correlated linearly with Smad3 at mRNA (coefficient: 0.94) and protein (coefficient: 097) level.

CONCLUSIONS

Legumain and Smad3 expression is highly expressed in mainly atherosclerotic plaque macrophages and linearly related, which is attenuated by statin therapy, suggesting legumain a potential Smad3 pathway-related marker of atherosclerosis.

Legumain Promotes Atherosclerotic Vascular Remodeling

Legumain, a recently discovered cysteine protease, is increased in both carotid plaques and plasma of patients with carotid atherosclerosis. Legumain increases the migration of human monocytes and human umbilical vein endothelial cells (HUVECs). However, the causal relationship between legumain and atherosclerosis formation is not clear. We assessed the expression of legumain in aortic atheromatous plaques and after wire-injury-induced femoral artery neointimal thickening and investigated the effect of chronic legumain infusion on atherogenesis in Apoe^-/- mice. We also investigated the associated cellular and molecular mechanisms in vitro, by assessing the effects of legumain on inflammatory responses in HUVECs and THP-1 monocyte-derived macrophages; macrophage foam cell formation; and migration, proliferation, and extracellular matrix protein expression in human aortic smooth muscle cells (HASMCs). Legumain was expressed at high levels in atheromatous plaques and wire injury-induced neointimal lesions in Apoe^-/- mice. Legumain was also expressed abundantly in THP-1 monocytes, THP-1 monocyte-derived macrophages, HASMCs, and HUVECs. Legumain suppressed lipopolysaccharide-induced mRNA expression of vascular cell adhesion molecule-1 (VCAM1), but potentiated the expression of interleukin-6 (IL6) and E-selectin (SELE) in HUVECs. Legumain enhanced the inflammatory M1 phenotype and oxidized low-density lipoprotein-induced foam cell formation in macrophages. Legumain did not alter the proliferation or apoptosis of HASMCs, but it increased their migration. Moreover, legumain increased the expression of collagen-3, fibronectin, and elastin, but not collagen-1, in HASMCs. Chronic infusion of legumain into Apoe^-/- mice potentiated the development of atherosclerotic lesions, accompanied by vascular remodeling, an increase in the number of macrophages and ASMCs, and increased collagen-3 expression in plaques. Our study provides the first evidence that legumain contributes to the induction of atherosclerotic vascular remodeling.

Legumain suppresses OxLDL-induced macrophage apoptosis through enhancement of the autophagy pathway

OBJECTIVE

Autophagy plays a prominent role in the pathogenesis of plaques formation and progression of atherosclerosis (AS). The cysteine protease legumain is known to participate in atherogenesis, but its function and underlying mechanism in AS macrophages remain unclear.

METHODS

The expressions of legumain in plaques isolated from AS patients and in macrophages stimulated with oxLDL were examined. Moreover, we effectively altered legumain expression in macrophages to characterize the effect of legumain on oxLDL-induced macrophage apoptosis. The expression of apoptotic and autophagic factors was analysed.

RESULTS

Legumain was present in plaques, and its expression was upregulated in macrophages treated with oxLDL. Suppressing legumain significantly increased oxLDL-induced macrophage apoptosis and the expression of caspase 3, caspase 9 and Bax. However, legumain overexpression decreased macrophage apoptosis upon oxLDL exposure and the levels of caspase 3, caspase 9 and Bax. In addition, recombinant legumain protein suppressed macrophage apoptosis. Biochemical experiments revealed that legumain deficiency decreased the levels of Beclin1 and LC3, whereas increased legumain expression increased the levels of Beclin1 and LC3 significantly.

CONCLUSION

Legumain regulates oxLDL-induced macrophage apoptosis by enhancing the autophagy pathway, which may also influence the vulnerability of atherosclerotic plaques.

Role of simvastatin and RORα activity in the macrophage apoptotic pathway

Objective:

Atherosclerosis is a chronic inflammatory condition and is one of the main causes of death worldwide. Macrophages play important roles in the formation of atherosclerotic plaques. Apoptosis is progressively observed while plaques develop, although the precise mechanisms and outcomes of apoptosis in atherosclerosis development and progression are still contradictory. This study was conducted to explore the effects of simvastatin and retinoic acid receptor-related orphan receptor alpha (RORa) ligands on apoptosis in human acute monocytic leukemia (THP-1) macrophage cells.

Methods:

Briefly, the occupancy of RORa in the promoter regions of apoptotic pathway genes was demonstrated in THP-1 cell lines using chromatin immunoprecipitation (ChIP) analysis. In order to modulate RORa activity, THP-1 macrophage cells were treated with specific ligands (CPG52608 and SR1001) and then viability as well as count of THP-1 macrophage cells were analyzed.

Results:

We observed that simvastatin and both RORa ligands had a tendency to decrease THP-1 macrophage cell viability in culture. When compared with non-treated controls, simvastatin significantly decreased cell viability (p=0.04) and cell count (p=0.03). However, this negative effect of simvastatin seemed to be partly prevented by RORa ligands. In addition, bioinformatics analysis of ChIP-on-chip data demonstrated that several genes that are involved in the apoptotic pathway were likely RORa target genes. These genes were involved in the regulation of apoptosis through various pathways.

Conclusion:

In summary, our study suggest that simvastatin-mediated macrophage apoptosis might be modulated by SR1001 administration. However, involvement of RORa in this modulation through potential apoptotic target genes remains elusive.

Increased levels of legumain in plasma and plaques from patients with carotid atherosclerosis

BACKGROUND AND AIMS

The cysteine protease legumain has been shown to be up-regulated in unstable atherosclerotic plaques. This study aims to further elucidate legumain in atherosclerosis, by examining legumain in plasma and carotid plaques from patients with carotid stenosis. Furthermore, legumain secretion from monocyte-derived macrophages treated with atherogenic lipids during macrophage polarization was studied.

METHODS

Plasma levels of legumain from patients with carotid stenosis (n = 254), healthy controls (n = 91), and secreted from monocyte-derived macrophages were assessed by enzyme-linked-immunosorbent assay. Quantitative PCR and immunoblotting of legumain were performed on isolated plaques and legumain localization was visualized by immunohistochemistry and fluorescence microscopy. Monocyte-derived macrophages polarized to M1 or M2 macrophages were treated with VLDL, oxLDL or cholesterol crystals (CC) and the level of legumain analysed.

RESULTS

Patients with carotid stenosis had significantly higher levels of plasma legumain compared with healthy controls (median 2.0 versus 1.5 ng/ml, respectively; p = 0.003), although there was no correlation between the level of legumain and the degree of stenosis, and legumain was not an independent factor to identify patients with carotid plaques. Moreover, patients with symptoms the last 2 months had higher expressions of mature legumain, cystatin C and E/M, and the macrophage markers CD80 (M1) and CD163 (M2). Legumain co-localized with both M1 and M2 macrophages within plaques, whereas legumain mRNA expression was significantly higher (p < 0.0001) in plaques compared to non-atherosclerotic arteries (controls). Furthermore, in vitro studies showed significantly increased secretion of legumain from pro-inflammatory M1 compared to pro-resolving M2 macrophages (p = 0.014), and particularly in M1 treated with CC. In plaques, legumain was localized to structures resembling foam cells.

CONCLUSIONS

Legumain is increased in both plasma and plaques of patients with carotid stenosis and might be a new and early biomarker of atherosclerosis.

New advances in the treatment of generalized anxiety disorder: the multimodal antidepressant vortioxetine

Generalized Anxiety Disorder (GAD) is a persistent condition characterized by chronic anxiety, exaggerated worry and tension, mainly comorbid with Major Depressive Disorder (MDD). Currently, selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors are recommended as first-line treatment of GAD. However, some patients may not respond to the treatment or discontinue due to adverse effects. Vortioxetine (VRX) is a multimodal antidepressant with a unique mechanism of action, by acting as 5-HT3A, 5-HT1D and 5-HT7 receptor antagonist, partial agonist at the 5-HT1A and 5-HT1B receptors and inhibitor at the 5-HT transporter. Preliminary clinical trials showed contrasting findings in terms of improvement of the anxiety symptomatology and/or cognitive impairment. Here, we aim to systematically review the evidence currently available on the efficacy, safety and tolerability of VRX in the treatment of GAD. The generalizability of results on the efficacy of VRX in patients with anxiety symptomatology and GAD is limited due to few and contrasting RCTs so far available. Only two studies, of which one prevention relapse trial, reported a significant improvement in anxiety symptomatology compared to three with negative findings.

Statins and myocardial infarction: Type, dose, and administration time: Does it matter?

Patients with ST-elevation myocardial infarction (STEMI) constitute a vulnerable group that demands the careful assessment and application of all the up-to-date clinical and experimental knowledge, with final aim, the improvement of their prognosis. Statins are an indispensable part of the primary and secondary prevention of coronary artery disease (CAD), not only due to their strong hypolipidemic effect, but also due to their numerous pleiotropic properties that play an important role in the treatment of CAD, especially when the more vulnerable group of STEMI patients is addressed. Nevertheless, there are still issues that require further discussion and clarification, such as the type of statin, the dose of the regimen, the administration time, and the treatment duration.

Combined use of probucol and cilostazol with atorvastatin attenuates atherosclerosis in moderately hypercholesterolemic rabbits

Background

Atherosclerotic cardiovascular disease is one of the major diseases that seriously impacts human health. Combined drug therapy may be efficacious in delaying the occurrence of cardiovascular events.

Aim

The current study was designed to investigate whether combined use of probucol (an anti-oxidant agent) with cilostazol (a platelet aggregation inhibitor) would increase the inhibitory effect of statins (a lipid-lowering agent) on atherosclerosis in moderately hypercholesterolemic rabbits.

Methods and Results

Thirty Japanese white rabbits were fed with a high cholesterol diet for 12 weeks, which was supplemented with either 0.005 % atorvastatin alone or 0.005 % atorvastatin plus 0.3 % probucol and 0.3 % cilostazol. Except for high-density lipoprotein cholesterol, no difference was found in plasma lipids among vehicle, statin, and the combined treatment group. However, atherosclerotic lesions were significantly reduced by statin treatment compared with vehicle. Moreover, we found that the anti-atherogenic effect of statin was further enhanced by the combined treatment, which was due to increased anti-inflammatory and anti-oxidant properties.

Conclusions

These data demonstrated that combined drug treatment exhibits potent athero-protective effects via pleiotropic functions, such as anti-inflammatory and anti-oxidative stress, which is independent of the lipid-lowering effect.

Legumain expression, activity and secretion are increased during monocyte-to-macrophage differentiation and inhibited by atorvastatin

Macrophages express several lysosomal cysteine proteases such as cathepsins and legumain. In this study, we assessed the expression, activity and secretion of legumain in cellular models of monocytes/macrophages. Macrophages were derived from M-CSF- or GM-CSF/IFNγ-stimulated human primary monocytes (M2 and M1, respectively), PMA-treated human THP-1 cells, or murine RAW264.7 macrophages. In both primary monocytes and THP-1 cells, monocyte-to-macrophage differentiation caused highly increased cellular expression and activity of legumain. Also, secretion of legumain from macrophages, but not from monocytes, was observed. Notably, M2 macrophages expressed significantly higher levels of active legumain than M1 macrophages, which are not previously reported. Legumain mRNA has been shown to be down-regulated in monocytes isolated from patients treated with the HMG-CoA reductase inhibitor atorvastatin. Interestingly, in our study, the active legumain produced by M2 macrophages was found to be inhibited by atorvastatin, which was reflected in aberrant cellular expression and processing.

Degradation of acetoacetyl-CoA synthetase, a ketone body-utilizing enzyme, by legumain in the mouse kidney

Acetoacetyl-CoA synthetase (AACS) is a ketone body-utilizing enzyme, which is responsible for the synthesis of cholesterol and fatty acids from ketone bodies in lipogenic tissues, such as the liver and adipocytes. To explore the possibility of AACS regulation at the protein-processing level, we investigated the proteolytic degradation of AACS. Western blot analysis showed that the 75.1kDa AACS was cleaved to form a protein of approximately 55kDa in the kidney, which has considerable high activity of legumain, a lysosomal asparaginyl endopeptidase. Co-expression of AACS and legumain in HEK 293 cells generated the 55kDa product from AACS. Moreover, incubation of recombinant AACS with recombinant legumain resulted in the degradation of AACS. Knockdown of legumain with short-hairpin RNA against legumain using the hydrodynamics method led to a decrease in the 55kDa band of AACS in mouse kidney. These results suggest that legumain is involved in the processing of AACS through the lysosomal degradation pathway in the kidney.

Simvastatin inhibits glucose metabolism and legumain activity in human myotubes

Simvastatin, a HMG-CoA reductase inhibitor, is prescribed worldwide to patients with hypercholesterolemia. Although simvastatin is well tolerated, side effects like myotoxicity are reported. The mechanism for statin-induced myotoxicity is still poorly understood. Reports have suggested impaired mitochondrial dysfunction as a contributor to the observed myotoxicity. In this regard, we wanted to study the effects of simvastatin on glucose metabolism and the activity of legumain, a cysteine protease. Legumain, being the only known asparaginyl endopeptidase, has caspase-like properties and is described to be involved in apoptosis. Recent evidences indicate a regulatory role of both glucose and statins on cysteine proteases in monocytes. Satellite cells were isolated from the Musculus obliquus internus abdominis of healthy human donors, proliferated and differentiated into polynuclear myotubes. Simvastatin with or without mevalonolactone, farnesyl pyrophosphate or geranylgeranyl pyrophosphate were introduced on day 5 of differentiation. After 48 h, cells were either harvested for immunoblotting, ELISA, cell viability assay, confocal imaging or enzyme activity analysis, or placed in a fuel handling system with [¹⁴C]glucose or [³H]deoxyglucose for uptake and oxidation studies. A dose-dependent decrease in both glucose uptake and oxidation were observed in mature myotubes after exposure to simvastatin in concentrations not influencing cell viability. In addition, simvastatin caused a decrease in maturation and activity of legumain. Dysregulation of glucose metabolism and decreased legumain activity by simvastatin points out new knowledge about the effects of statins on skeletal muscle, and may contribute to the understanding of the myotoxicity observed by statins.

Does combination therapy with statins and fibrates prevent cardiovascular disease in diabetic patients with atherogenic mixed dyslipidemia?

Type 2 diabetes mellitus (T2DM) is associated with the development and progression of cardiovascular disease (CVD). Statins have an established efficacy in the management of dyslipidemia primarily by decreasing the levels of low-density lipoprotein cholesterol and thus decreasing CVD risk. They also have a favorable safety profile. Despite the statin-mediated benefit of CVD risk reduction a residual CVD risk remains, especially in T2DM patients with high triglyceride (TG) and low high-density lipoprotein cholesterol (HDL-C) values. Fibrates decrease TG levels, increase HDL-C concentrations, and improve many other atherosclerosis-related variables. Fibrate/statin co-administration improves the overall lipoprotein profile in patients with mixed dyslipidemia and may reduce the residual CVD risk during statin therapy. However, limited data exists regarding the effects of statin/fibrate combination on CVD outcomes in patients with T2DM. In the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study the statin/fibrate combination did not significantly reduce the rate of CVD events compared with simvastatin/placebo in patients with T2DM. However, it did show a possible benefit in a pre-specified analysis in the subgroup of patients with high TG and low HDL-C levels. Furthermore, in the ACCORD study the simvastatin/fenofibrate combination significantly reduced the rate of progression of retinopathy compared with statin/placebo administration in patients with T2DM. The present review presents the available data regarding the effects of statin/fibrate combination in patients with T2DM and atherogenic mixed dyslipidemia.

Simvastatin but not bezafibrate decreases plasma lipoprotein-associated phospholipase A₂ mass in type 2 diabetes mellitus: relevance of high sensitive C-reactive protein, lipoprotein profile and low-density lipoprotein (LDL) electronegativity

OBJECTIVE

Plasma lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) levels predict incident cardiovascular disease, impacting Lp-PLA(2) as an emerging therapeutic target. We determined Lp-PLA(2) responses to statin and fibrate administration in type 2 diabetes mellitus, and assessed relationships of changes in Lp-PLA(2) with subclinical inflammation and lipoprotein characteristics.

METHODS

A placebo-controlled cross-over study (three 8-week treatment periods with simvastatin (40 mg daily), bezafibrate (400mg daily) and their combination) was carried out in 14 male type 2 diabetic patients. Plasma Lp-PLA(2) mass was measured by turbidimetric immunoassay.

RESULTS

Plasma Lp-PLA(2) decreased (-21 ± 4%) in response to simvastatin (p<0.05 from baseline and placebo), but was unaffected by bezafibrate (1 ± 5%). The drop in Lp-PLA(2) during combined treatment (-17 ± 3%, p<0.05) was similar compared to that during simvastatin alone. The Lp-PLA(2) changes during the 3 active lipid lowering treatment periods were related positively to baseline levels of high sensitive C-reactive protein, non-HDL cholesterol, triglycerides, the total cholesterol/HDL cholesterol ratio and less LDL electronegativity (p<0.02 to p<0.01), and inversely to baseline Lp-PLA(2) (p<0.01). LpPLA(2) responses correlated inversely with changes in non-HDL cholesterol, triglycerides and the total cholesterol/HDL cholesterol ratio during treatment (p<0.05 to p<0.02).

CONCLUSIONS

In type 2 diabetes mellitus, plasma Lp-PLA(2) is likely to be lowered by statin treatment only. Enhanced subclinical inflammation and more severe dyslipidemia may predict diminished LpPLA(2) responses during lipid lowering treatment, which in turn appear to be quantitatively dissociated from decreases in apolipoprotein B lipoproteins. Conventional lipid lowering treatment may be insufficient for optimal LpPLA(2) lowering in diabetes mellitus.

Increased oxidative stress in foam cells obtained from hemodialysis patients

Premature atherosclerosis represents the main cause of mortality among end-stage renal disease patients (ESRD). Increased inflammation and oxidative stress are involved in initiation and progression of the atherosclerotic plaque. As foam cells are capable of producing significant amounts of inflammatory mediators and free radicals, we hypothesized that foam cells from uremic patients could produce more inflammation and oxidative stress than foam cells from normal people and be, somehow, involved in the accelerated atherosclerosis of uremia. To test this hypothesis, the levels of a few markers of inflammation and oxidative stress: Tumor necrosis factor-α, inducible nitric oxide synthase, malondialdehyde, nitric oxide by-products were measured in the supernatants of macrophage-derived foam cells cultures from 18 hemodialysis patients and 18 apparently healthy individuals controls. Malondialdehyde levels in the supernatant of cell cultures (macrophages stimulated or not with native and oxidized lipoprotein) were significantly increased in uremic patients; no statistically significant difference was found between the supernatant concentrations of nitric oxide by-products, inducible nitric oxide synthase activity, and tumor necrosis factor-α between patients and controls. Our results, obtained with human macrophages and macrophage-derived foam cells, are compatible with the theory that increased cellular oxidative stress and inflammatory activity in ESRD patients could accelerate the atherosclerotic process. The present culture protocol showed it is possible to use human mononuclear cells to evaluate the oxidative metabolism of foam cells, which are considered to be the initial step of atherosclerotic lesions.

Effect of atorvastatin therapy on oxidant-antioxidant status and atherosclerotic plaque formation

Background:

The aim of this study was to determine the oxidant–antioxidant status and lipid peroxidation products, as well as paraoxonase and atherosclerotic plaque formation, in a hypercholesterolemic atherosclerosis rabbit model to investigate the effects of atorvastatin in the atherosclerotic process.

Methods:

Forty male New Zealand rabbits were divided into four groups, ie, a control group receiving standard pellets, a group receiving atorvastatin therapy, a hypercholesterolemic group receiving an atherogenic diet, and a group receiving both an atherogenic diet and atorvastatin.

Results:

The atherogenic diet increased the levels of low-density lipoprotein (LDL) thiobarbituric acid reactive substances (1.84 vs 3.79 nmol/mg protein) and LDL-conjugated diene (147 vs 318 μmol/mg protein) after induction of oxidation by Cu²⁺, despite an increase of superoxide dismutase activity. Treatment with atorvastatin limited LDL oxidation significantly (LDL thiobarbituric acid reactive substances 2.19 nmol/mg protein, LDL-conjugated diene 222 μmol/mg protein). Paraoxonase, which prevents LDL oxidation and inactivates LDL-derived oxidized phospholipids, showed a pronounced decrease in the group receiving the atherogenic diet (110 U/L to 28 U/L), and atorvastatin treatment increased paraoxonase activity. Histological examination of arcus aorta tissues from the hypercholesterolemic group showed abundant plaque formation surrounding and obstructing the lumen, whereas treatment with atorvastatin prevented or limited plaque formation, keeping the plaque thin and localized.

Conclusion:

Atorvastatin has dramatic antiatherosclerotic effects, part of which seems to be due to the antioxidant features of the parent drug and/or its metabolites, favoring inhibition of LDL oxidation.

Long-term high-dose atorvastatin decreases brain oxidative and nitrosative stress in a preclinical model of Alzheimer disease: a novel mechanism of action

Alzheimer disease (AD) is an age-related neurodegenerative disorder characterized by progressive memory loss, inability to perform the activities of daily living and personality changes. Unfortunately, drugs effective for this disease are limited to acetylcholinesterase inhibitors that do not impact disease pathogenesis. Statins, which belong to the class of cholesterol-reducing drugs, were proposed as novel agents useful in AD therapy, but the mechanism underlying their neuroprotective effect is still unknown. In this study, we show that atorvastatin may have antioxidant effects, in aged beagles, that represent a natural higher mammalian model of AD. Atorvastatin (80 mg/day for 14.5 months) significantly reduced lipoperoxidation, protein oxidation and nitration, and increased GSH levels in parietal cortex of aged beagles. This effect was specific for brain because it was not paralleled by a concomitant reduction in all these parameters in serum. In addition, atorvastatin slightly reduced the formation of cholesterol oxidation products in cortex but increased the 7-ketocholesterol/total cholesterol ratio in serum. We also found that increased oxidative damage in the parietal cortex was associated with poorer learning (visual discrimination task). Thus, a novel pharmacological effect of atorvastatin mediated by reducing oxidative damage may be one mechanism underlying benefits of this drug in AD.