Coronary artery disease (CAD) is the leading cause of death worldwide. The efficacy and safety of statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) in primary and secondary prevention of CAD are confirmed in several large studies. It is well known that statins have some pleiotropic, anti-atherosclerotic effects. We review the molecular mechanisms underlying the beneficial effects of statins revealed in recently published studies. Endothelial cell injury is regarded as the classic stimulus for the development of atherosclerotic lesions. In addition, the inflammatory process plays an important role in the aetiology of atherosclerosis. In particular, chronic inflammation plays a key role in coronary artery plaque instability and subsequent occlusive thrombosis. Our previous reports and others have demonstrated beneficial effects of statins on endothelial dysfunction and chronic inflammation in CAD. A better understanding of the molecular mechanism underlying the effectiveness of statins against atherosclerosis may provide a novel therapeutic agent for the treatment of coronary atherosclerosis. The present review summarizes the cellular and molecular mechanism of statins against coronary atherosclerosis.

INTRODUCTION

As coronary artery disease (CAD) continues to be a leading cause of death around the world, primary and secondary prevention are of great importance. Chronic inflammation of the arterial wall is a key element in the pathogenesis of atherosclerosis [1]. Sites of atherosclerotic plaque development in the arterial wall are characterized by monocyte infiltration [2]. Low-density lipoprotein-cholesterol (LDL-C) is an established risk factor of CAD. The efficacy and safety of statins [3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors], which decrease levels of LDL-C, are confirmed in the treatment of CAD. Many clinical trials have indicated that statins reduce LDL-C levels without increasing complications, and improve prognosis. In addition to lipid lowering, statins have some pleiotropic effects of the anti-atherosclerotic effects, as supported by evidence from both experimental and clinical studies. Clinical studies demonstrate that statins reduce circulating C-reactive protein (CRP), proinflammatory cytokines such as interleukin (IL)-1, IL-6 and tumour necrosis factor α (TNF-α), and cell adhesion molecule levels in patients with cardiovascular risk factors [3,4]. In addition, some clinical studies have shown that statins consistently improve endothelial function in patients with CAD or cardiovascular risk factors [57]. Effects of statins on endothelial dysfunction and inflammation have been considered responsible for the protective effects of these agents in patients with CAD. The anti-inflammatory properties of statins are also likely to account for their role in primary and secondary prevention of stroke [8,9], improvement of short-term outcomes in patients with acute coronary syndrome (ACS) [10], reduction of the risk of atrial fibrillation post-coronary artery bypass grafting (CABG) [11] and in patients with heart failure [12], all of which have a less clear association with LDL lowering. The study Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) demonstrated that statin treatment reduces cardiovascular risk in primary prevention, even in healthy individuals with elevated CRP levels [13].

It has also been reported that the impact of statins on hepatic LDL-receptor-related protein 1 expression and its regulation by sterol response element-binding protein-2 is considered a mechanism of action for the cardiovascular protective effects of statins [14]. These observations suggest that statins have not only a lipid-lowering effect but also beneficial pleiotropic effects of many kinds on cardiovascular diseases such as CAD, stroke and atrial fibrillation post-CABG.

In the present review, we summarize the current knowledge about the cellular and molecular mechanisms of statins in coronary atherosclerosis. The main focus is on clinical evidence, and key observations from animal experiments and basic science are included. The present review starts with the mechanism of endothelial dysfunction and chronic inflammation in coronary atherosclerosis, and then deals with the relationship between cellular and molecular mechanism of statins and their anti-atherosclerotic effects, with acceptance of the concept that the two features are closely connected.

LIPID-LOWERING EFFECTS OF STATINS AND CARDIOVASCULAR RISK REDUCTION FROM CLINICAL TRIALS

Large randomized clinical studies have established the beneficial effects of lipid lowering in the primary and secondary prevention of CAD [1518]. A summary of the important randomized clinical trials on statins in primary and secondary prevention of CAD is provided in Table 1 [7,13,15,1724]. Some of these trials showed early clinical evidence for the beneficial effects of statins independent of their lipid-lowering properties. The Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID) trial showed that pravastatin treatment reduced coronary mortality risk even in patients with LDL-C <100 mg/dl [18]. The Myocardial Ischaemia Reduction with Aggressive Cholesterol Lowering (MIRACL) trial yielded evidence of atorvastatin's anti-inflammatory effects in patients with ACS [7]. Treatment with high-dose atorvastatin for 16 weeks in patients with ACS, starting 24–96 h after hospital admission, significantly reduced ischaemic events [7]. The MIRACL trial also demonstrated that baseline inflammatory markers such as CRP and serum amyloid α independently predicted the risk for stroke, and atorvastatin reduced the levels of these biomarkers [25,26]. The Atorvastatin for Reduction of MYocardial Damage during Angioplasty (ARMYDA–RECAPTURE) trial showed that additional loading with high-dose atorvastatin before percutaneous coronary intervention reduced myocardial injury and cardiovascular mortality in patients who were already on chronic statin treatment [27]. Clinical reports on short-term treatment of patients with CAD also showed that statin therapy using simvastatin or atorvastatin, but not ezetimibe, is associated with improved endothelial vasodilator function, although LDL-C levels were significantly reduced in all four groups (ezetimibe, ezetimibe as an add-on to chronic simvastatin, escalation from chronic 10–40 mg/day of atorvastatin or new monotherapy with 40 mg/day of atorvastatin) [28].

Table 1
Important large randomized clinical trials on statins and clinical outcomes in the context of CAD
StudyPopulationTreatmentOutcome
4S [184444 patients with CAD Simvastatin vs placebo Simvastatin reduced risk for coronary death 
WOSCOPS [166595 men without CAD Pravastatin vs placebo Pravastatin reduced coronary events and coronary mortality 
LIPID [179014 patients with CAD Pravastatin vs placebo Pravastatin reduced coronary mortality risk 
MIRACL [73086 patients with ACS Atorvastatin vs placebo Atorvastatin reduced risk for recurrent ischaemic events 
ASCOT–LLA [1919 342 patients with hypertension Atorvastatin vs placebo Atorvastatin reduced risk for primary events 
CARE [204159 patients with MI Pravastatin vs placebo Pravastatin reduced risk for non-fatal AMI 
TNT [2210 001 patients with CAD Atorvastatin (high vs low dose) Reduced risk for MACEs with high-dose treatment 
MEGA study [143866 patients with hypercholesterolaemia Pravastatin + diet vs diet Pravastatin reduced risk for CAD 
JUPITER [1317 802 participants (LDL <130 mg/day, CRP >2.0 mg/l) Rosuvastatin vs placebo Rosuvastatin reduced risk for MACEs 
PROVE IT–TIMI22 [234162 patients with ACS Atorvastatin vs pravastatin Atorvastatin reduced risk for death or CV events 
StudyPopulationTreatmentOutcome
4S [184444 patients with CAD Simvastatin vs placebo Simvastatin reduced risk for coronary death 
WOSCOPS [166595 men without CAD Pravastatin vs placebo Pravastatin reduced coronary events and coronary mortality 
LIPID [179014 patients with CAD Pravastatin vs placebo Pravastatin reduced coronary mortality risk 
MIRACL [73086 patients with ACS Atorvastatin vs placebo Atorvastatin reduced risk for recurrent ischaemic events 
ASCOT–LLA [1919 342 patients with hypertension Atorvastatin vs placebo Atorvastatin reduced risk for primary events 
CARE [204159 patients with MI Pravastatin vs placebo Pravastatin reduced risk for non-fatal AMI 
TNT [2210 001 patients with CAD Atorvastatin (high vs low dose) Reduced risk for MACEs with high-dose treatment 
MEGA study [143866 patients with hypercholesterolaemia Pravastatin + diet vs diet Pravastatin reduced risk for CAD 
JUPITER [1317 802 participants (LDL <130 mg/day, CRP >2.0 mg/l) Rosuvastatin vs placebo Rosuvastatin reduced risk for MACEs 
PROVE IT–TIMI22 [234162 patients with ACS Atorvastatin vs pravastatin Atorvastatin reduced risk for death or CV events 

AMI, acute myocardial infarction; CV, cardiovascular; MACE, major adverse cardiac event; MI, myocardial infarction.

Although both the pleiotropic and the lipid-lowering effects of statins play an important role in the prevention of CAD, these studies provide strong evidence that statin treatment could be extended to individuals without hyperlipidaemia for prevention of CAD due to its anti-inflammatory effects, improved endothelial dysfunction, coronary plaque stabilization and other vasoprotective effects.

TELOMERE BIOLOGY IN ENDOTHELIAL PROGENITOR CELLS

The metabolic syndrome is a cluster of insulin resistance, impaired glucose tolerance, dyslipidaemia, obesity and elevated blood pressure; it has reached epidemic proportions in industrialized countries [29]. A large cohort study has revealed that the metabolic syndrome is associated with an increased risk of CAD [30]. These classic risk factors for atherosclerosis induce endothelial injury, and impaired endothelial function is a predictor of risk for subsequent cardiovascular events [31]. Oxidative stress plays a critical role in the pathogenesis of CAD in patients with the metabolic syndrome [32]. Oxidative stress has been implicated in the development of atherosclerosis through a variety of mechanisms, especially those leading to endothelial dysfunction [33,34]. Oxidative stress also induces damage to or apoptosis of endothelial cells [35].

Asahara et al. [36] have identified that normal adults have a small number of circulating endothelial progenitor cells (EPCs) in their peripheral blood. It has also been reported that patients at risk of CAD have a decreased number of circulating EPCs with impaired activity [37]. EPCs are regarded as having a key role in the maintenance of vascular integrity and the replacement of apoptotic or damaged endothelial cells in response to various cardiovascular risk factors, such as metabolic syndrome [38,39]. Cell division is associated with telomere shortening, leading to senescence once the telomere length has reached a critical threshold [40]. Telomeres are composed of non-coding, double-stranded repeats of a G-rich, tandem, DNA-sequence TTAGGG extending over 6–15 kbp at the end of eukaryotic chromosomes, and are necessary for both successful DNA replication and chromosomal integrity [40]. Telomere shortening is modulated by the rate of cell turnover and oxidative stress [41]. Our previous study reported that the telomere length of EPCs was significantly shorter in CAD patients compared with control individuals [42]. The telomere length of EPCs was weakly negatively correlated with oxidative DNA stress [8-hydroxyl-2′-deoxyguanosine mean fluorescent intensity (MFI)] [42]. In addition, telomere shortening and oxidative DNA damage in EPCs were higher in CAD patients with than in those without the metabolic syndrome [42]. From these observations, EPC telomere shortening via oxidative DNA damage may play an important role in the pathogenesis of CAD. In addition, the metabolic syndrome may be one of the triggers for increased oxidative DNA damage and EPC telomere shortening in CAD patients.

The report of Spyridopoulos et al. [43] has revealed a beneficial effect of statins on telomere biology in cultured EPCs. A clinical trial using an intravascular ultrasound method for imaging coronary vessel walls (measurement of atheroma burden) showed a reduced progression of coronary atheroma burden after intensive lipid-lowering therapy with atorvastatin, whereas moderate lipid-lowering therapy with pravastatin showed an increase in coronary atheroma burden in patients with CAD [44]. On the basis of these reports, this property of intensive lipid-lowering therapy with statins may contribute to biologically relevant activities, including EPC telomere biology and angiogenesis. We therefore carried out a prospective and randomized study (intensive lipid-lowering therapy with 10 mg/day of atorvastatin vs moderate lipid-lowering therapy with 10 mg/day of pravastatin) [45]. Intensive lipid-lowering therapy increased EPC numbers and prevented EPC telomere shortening, whereas moderate lipid-lowering therapy did not change EPC numbers or prevent EPC telomere shortening (Figure 1). In addition, treatment with atorvastatin affected inhibition of EPC telomere shortening compared with pravastatin in our in vitro study using human cultured EPCs (Figure 2). From these reports, intensive lipid-lowering therapy may prevent EPC telomere erosion in patients with CAD, possibly contributing to the beneficial effects of intensive lipid-lowering therapy in this disorder.

Effect of intensive (n=50) and moderate (n=50) lipid-lowering therapy on relative telomere length (RTL) and oxidative DNA stress (8-hydroxyl-2′-deoxyguanosine MFI) of EPCs in patients with CAD

Figure 1
Effect of intensive (n=50) and moderate (n=50) lipid-lowering therapy on relative telomere length (RTL) and oxidative DNA stress (8-hydroxyl-2′-deoxyguanosine MFI) of EPCs in patients with CAD

Intensive lipid-lowering therapy (A) did not change the RTL and (C) significantly decreased 8-hydroxyl-2′-deoxyguanosine MFI, whereas moderate lipid-lowering therapy (B) shortened the RTL and (D) did not change 8-hydroxyl-2′-deoxyguanosine MFI. (This Figure was reproduced from Satoh et al. [45].)

Figure 1
Effect of intensive (n=50) and moderate (n=50) lipid-lowering therapy on relative telomere length (RTL) and oxidative DNA stress (8-hydroxyl-2′-deoxyguanosine MFI) of EPCs in patients with CAD

Intensive lipid-lowering therapy (A) did not change the RTL and (C) significantly decreased 8-hydroxyl-2′-deoxyguanosine MFI, whereas moderate lipid-lowering therapy (B) shortened the RTL and (D) did not change 8-hydroxyl-2′-deoxyguanosine MFI. (This Figure was reproduced from Satoh et al. [45].)

Effect of atorvastatin and pravastatin on telomere length in cultured EPCs stimulated with oxidative stress (t-BHP and BSO)

Figure 2
Effect of atorvastatin and pravastatin on telomere length in cultured EPCs stimulated with oxidative stress (t-BHP and BSO)

Control value is defined as 100%. Relative telomere length (RTL) was decreased in tert-butyl hydroperoxide (t-BHP)- or L-buthionine sulfoximine (BSO)-stimulated EPCs treated with drug vehicle (0.05% DMSO) compared with controls. Percentage changes in RTL were lower in t-BHP- or BSO-stimulated EPCs treated with atorvastatin and pravastatin than in those treated with vehicle. In addition, percentage changes in the RTL were lower in t-BHP- or BSO-stimulated EPCs treated with atorvastatin compared with those treated with pravastatin. (This Figure was reproduced from Satoh et al. [45].)

Figure 2
Effect of atorvastatin and pravastatin on telomere length in cultured EPCs stimulated with oxidative stress (t-BHP and BSO)

Control value is defined as 100%. Relative telomere length (RTL) was decreased in tert-butyl hydroperoxide (t-BHP)- or L-buthionine sulfoximine (BSO)-stimulated EPCs treated with drug vehicle (0.05% DMSO) compared with controls. Percentage changes in RTL were lower in t-BHP- or BSO-stimulated EPCs treated with atorvastatin and pravastatin than in those treated with vehicle. In addition, percentage changes in the RTL were lower in t-BHP- or BSO-stimulated EPCs treated with atorvastatin compared with those treated with pravastatin. (This Figure was reproduced from Satoh et al. [45].)

ACTIVATION OF TOLL-LIKE RECEPTOR 4 SIGNALLING IN CORONARY ATHEROSCLEROSIS

Toll-like receptors (TLRs) have been identified as key recognition components of pathogen-associated molecular patterns (PAMPs) controlling innate immune responses in mammals [46]. A family of TLRs has been defined as a key component of many kinds of PAMP recognition machinery [46]. Ten TLRs have been reported in mammalian species, and these appear to recognize distinct PAMPs controlling innate immune responses [47]. When TLRs on monocyte/macrophages are activated, this leads to activation of the nuclear factor (NF)-κB pathway, which brings about the production of proinflammatory cytokines and expression of co-stimulatory molecules, resulting in the induction of acquired immunity [4850]. Our previous reports have demonstrated that an activation of the TLR4 signal is involved in the downstream release of inflammatory cytokines in circulating monocytes obtained from patients with CAD [51,52]. In addition, expression of TLR4 in infiltrating macrophages within the coronary arteries may be an important factor underlying coronary plaque destabilization and rupture in CAD [53]. In agreement with these reports, our previous study showed an increase in TLR4 levels (both mRNA and protein levels) in the CAD group compared with the non-CAD group [53]. A mouse model has demonstrated that loss of TLR4 reduced the severity of atherosclerosis and altered the atherosclerotic plaque [54]. It has been suggested that there is a potential pathophysiological link between activation of the TLR4 signal and the progression of coronary atherosclerosis.

It is already known that statins exert potent anti-atherosclerotic effects, which are mediated not only by their anti-hyperlipidaemic properties but also by their anti-inflammatory properties [55,56]. In particular, administration of atorvastatin attenuated the activation of TLR4 expression and its downstream pathway, including NF-κB signalling in a lipopolysaccharide (LPS)-stimulated human cell line [57]. A prospective, randomized and open-label study showed a high simvastatin dose or a combination of low-dose simvastatin with ezetimibe reduced, to a similar extent, TLR2, TLR4 membrane expression, and LPS-induced IL-6 and IL-1β production in monocytes of patients with hypercholesterolaemia [58].

ENDOTHELIAL SENESCENCE BIOLOGY

The integrity and functional activity of the endothelial monolayer are essential for protection against the initiation of atherosclerosis [59]. In particular, senescence of endothelial cells may play an important role in the pathogenesis of atherosclerotic disorders including CAD [6062]. It has been reported that circulating EPCs may have a key role in the maintenance of endothelial integrity and the replacement of apoptotic or damaged endothelial cells [36,38]. Our previous report has also demonstrated that a decreased EPC count due to telomere shortening may be involved in the pathogenesis of CAD [42,45].

Silent information regulator 1 (SIRT1), a member of the class of proteins referred to as sirtuins, is a mammalian homologue of yeast Sir2 and belongs to the Sir2 family [63]. SIRT1 is identified as an NAD-dependent deacetylase that is responsible for maintenance of chromatin silencing and genome stability [64]. SIRT1 has recently been reported to be a novel modulator of vascular endothelial cell homoeostasis, and shown to exert anti-atherosclerotic effects against endothelial dysfunction by preventing stress-induced senescence in in vitro models [65,66].

A recent study has reported that treatment with statins, such as atorvastatin, pravastatin and pitavastatin, inhibits endothelial senescence and enhances SIRT1 in human umbilical vein endothelial cells stimulated with hydrogen peroxide [67]. An in vitro model using cultured endothelial cells reported that knockdown of SIRT1 mitigated the antioxidant and anti-inflammatory vascular effects against oxidative stress in cultured coronary vascular endothelial cells [68]. An experimental model with diabetic atherosclerosis has reported that SIRT1 mRNA levels in an abdominal aorta obtained from diabetic rats were significantly lower than those from non-diabetic rats [69]. However, it remains unknown whether statins have these anti-senescent properties in EPCs obtained from patients with CAD. Our previous report demonstrated that SIRT1 levels (both mRNA and protein levels) were lower in EPCs obtained from patients with CAD than in control individuals [70]. In addition, to evaluate the effects of statins (atorvastatin or rosuvastatin) on SIRT1 levels, we carried out a prospective, randomized and single-blinded study (atorvastatin vs rosuvastatin). This clinical study showed that the atorvastatin group had markedly increased SIRT1 levels, whereas the rosuvastatin group showed no change in SIRT1 levels (Figure 3) [70]. This study suggested that impairment of SIRT1 regulation may contribute to EPC senescence, and thereby play an important role in the progression of coronary atherosclerosis. In addition, statins, in particular atorvastatin, up-regulate SIRT1 expression in CAD, possibly contributing to the beneficial effects of statins on endothelial function in this disorder [70]

Effect of atorvastatin (n=35) and rosuvastatin (n=35) on levels of SIRT1 in patients with CAD

Figure 3
Effect of atorvastatin (n=35) and rosuvastatin (n=35) on levels of SIRT1 in patients with CAD

Representative examples are shown in (A) and (B). Treatment with atorvastatin significantly increased both (C) SIRT1 mRNA and (D) SIRT1 protein levels compared with rosuvastatin. (This Figure was reproduced from Tabuchi et al. [70].)

Figure 3
Effect of atorvastatin (n=35) and rosuvastatin (n=35) on levels of SIRT1 in patients with CAD

Representative examples are shown in (A) and (B). Treatment with atorvastatin significantly increased both (C) SIRT1 mRNA and (D) SIRT1 protein levels compared with rosuvastatin. (This Figure was reproduced from Tabuchi et al. [70].)

NLRP3 INFLAMMASOME ACTIVATION IN CAD

It is well known that chronic inflammation of the arterial wall is a key element in the pathogenesis of atherosclerosis [1]. In particular, sites of atherosclerotic plaque development in the arterial wall are characterized by infiltration of monocytes [2]. As shown in the section above, these cells of the innate immune system are activated through TLRs and release proinflammatory cytokines such as IL-1β and IL-18 [71]. It has been reported that both IL-1β and IL-18 are potent proatherogenic cytokines [72,73]. Clinical reports have shown that increases in IL-1β and IL-18 levels are related to clinical severity in patients with CAD [74,75]. In addition, knocking out IL-1β and IL-18 in atherosclerosis-prone ApoE−/− mice leads to attenuation of coronary atherosclerosis development [76,77].

A recent report showed that the NLRP-3 inflammasome (i.e. nucleotide-binding domain, leucine-rich-containing family, pyrin-domain containing-3) is activated in response to a variety of signals that are indicative of damage to the host, including tissue damage, metabolic stress and infection [78]. The NLRP-3 inflammasome contributes to the pathogenesis of metabolic diseases as a sensor for metabolic danger and also plays a central role in chronic inflammation, resulting in IL-1β and IL-18 maturation [79,80]. The NLRP-3 inflammasome can be activated by various kinds of host-derived molecules including excess ATP, glucose, reactive oxygen species and cholesterol crystals [81]. In particular, cholesterol crystal-induced NLRP-3 inflammasome activation in macrophages may represent an important link between cholesterol metabolism and inflammation in atherosclerotic lesions [82].

Our previous study showed that levels of the NLRP-3 inflammasome were higher in patients with CAD than in control individuals (Figure 4A) [83]. Plasma levels of IL-1β and IL-18 were higher in patients with CAD than in control individuals, and were positively correlated with NLRP-3 inflammasome levels (Figures 4B and 4C) [83]. In addition, a randomized clinical study using statins showed the atorvastatin group to have a marked decrease, not only in NLRP-3 inflammasome but also in plasma levels of IL-1β and IL-18, whereas the rosuvastatin group showed no change in these levels (Figure 4D) [83]. An in vitro study demonstrated that treatment with atorvastatin diminished IL-1β and IL-18 levels via repression of the NLRP-3 inflammasome, compared with treatment with rosuvastatin in our in vitro study using human monocytes [83]. From this study, the activation of the NLRP-3 inflammasome may contribute to chronic inflammation via maturation of IL-1β and IL-18, and may be related to progression of coronary atherosclerosis. In addition, statins, in particular atorvastatin, down-regulate IL-1β and IL-18 maturation via inhibition of the NLRP-3 inflammasome in CAD, possibly contributing to the beneficial effects of statins on chronic inflammation in this disorder.

Levels of the NLRP-3 inflammasome in CAD and non-CAD groups: comparison of levels of NLRP3 inflammasome mRNA and NLRP-3 inflammasome MFI between CAD and non-CAD groups

Figure 4
Levels of the NLRP-3 inflammasome in CAD and non-CAD groups: comparison of levels of NLRP3 inflammasome mRNA and NLRP-3 inflammasome MFI between CAD and non-CAD groups

Comparison of levels of IL-1β and IL-18 between (A) CAD and (B) non-CAD groups. (C) Correlation of the NLRP-3 inflammasome, IL-1β and IL-18 in all participants. (D) Effect of atorvastatin (n=30) and rosuvastatin (n=30) on NLRP-3 inflammasome levels in patients with CAD. (This Figure was reproduced from Satoh et al. [83].)

Figure 4
Levels of the NLRP-3 inflammasome in CAD and non-CAD groups: comparison of levels of NLRP3 inflammasome mRNA and NLRP-3 inflammasome MFI between CAD and non-CAD groups

Comparison of levels of IL-1β and IL-18 between (A) CAD and (B) non-CAD groups. (C) Correlation of the NLRP-3 inflammasome, IL-1β and IL-18 in all participants. (D) Effect of atorvastatin (n=30) and rosuvastatin (n=30) on NLRP-3 inflammasome levels in patients with CAD. (This Figure was reproduced from Satoh et al. [83].)

BIOLOGY OF THE miRNAs

It has been reported that miRNAs are small, non-coding RNAs that negatively or positively regulate protein expression at the post-transcriptional level [84]. Through specific targeting of the 3′-UTRs of multicellular eukaryotic miRNAs, miRNAs down-regulate gene expression by either inducing degradation of target mRNA or impairing its translation [84,85]. This section introduces some important miRNAs for the pathogenesis of coronary atherosclerosis.

The miRNAs miR-221 and miR-222

It has also been demonstrated that miR-221 and miR-222 may control proliferation and differentiation of CD34-positive haematopoietic progenitor cells [86]. In addition, selective depletion of miR-221 and miR-222 in vitro has been shown to critically affect the specific endothelial cell miRNA expression pattern, suggesting that both miR-221 and miR-222 may play an important role as transcription factors in endothelial cells [87]. Another study demonstrated an anti-angiogenic function of miR-221 and miR-222 in human endothelial cells [88]. An miR-221- and miR-222-transfected endothelial cell model has shown that miR-221 and miR-222 inhibit cell migration, tube formation and wound healing in endothelial cells in vitro [89]. Both miR-221 and miR-222 belong to the same family, and are located in close proximity to chromosome Xp11.3 [9092]. Our previous study analysed levels of miR-221 and miR-222 in EPCs obtained from patients with CAD compared with control individuals [93]. In addition, this study carried out a prospective, randomized and single-blinded (researchers were blinded to patients' treatment groups) study in two treatment groups [10 mg/day of atorvastatin (n=22) or 10 mg/day of pravastatin] [93]. Levels of both miR-221 and miR-222 in EPCs were higher in patients with CAD than in control individuals [93]. Treatment with atorvastatin decreased miR-221/-222 levels, whereas treatment with pravastatin did not alter them (Figure 5) [92]. Changes in LDL-C levels were positively correlated with changes in miR-221/-222 levels in the atorvastatin group, but not in the pravastatin group [93]. This study demonstrates that miR-221/-222 levels decrease and EPC numbers increase after treatment with atorvastatin, but not after treatment with pravastatin, possibly contributing to the beneficial effects of lipid-lowering therapy with atorvastatin in this disorder

Effect of atorvastatin (n=22) and pravastatin (n=22) on miR-221/-222 levels in EPCs in patients with CAD

Figure 5
Effect of atorvastatin (n=22) and pravastatin (n=22) on miR-221/-222 levels in EPCs in patients with CAD

(A, C) Treatment with atorvastatin significantly decreased miR-221/-222 levels, whereas (B, D) treatment with pravastatin did not change miR-221 or miR-222 levels. (This Figure was reproduced from Minami [93], © 2009, with the permission of John Wiley & Sons.)

Figure 5
Effect of atorvastatin (n=22) and pravastatin (n=22) on miR-221/-222 levels in EPCs in patients with CAD

(A, C) Treatment with atorvastatin significantly decreased miR-221/-222 levels, whereas (B, D) treatment with pravastatin did not change miR-221 or miR-222 levels. (This Figure was reproduced from Minami [93], © 2009, with the permission of John Wiley & Sons.)

Let-7i

A recent in vitro study has reported that let-7i, a member of the let-7 family of miRNAs, targets TLR4 mRNA and limits the expression of this pathogen molecular pattern receptor, resulting in decreased TLR4 expression [94]. It has therefore been suggested that the expression of let-7i directly regulates TLR4 expression through the RNA interference pathway. Moreover, a decrease in let-7i expression is associated with microbial infection-induced up-regulation of TLR4 in infected cells [94]. A human cell-line model has also shown that a decrease in let-7i expression resulted in up-regulation of TLR4, followed by an increase in NF-κB signalling [94]. In addition, let-7i directly regulates not only TLR4 expression but also NF-κB gene expression in the TLR4 downstream pathway [95]. Our clinical randomized study showed that treatment with atorvastatin increased let-7i levels and reduced TLR4 levels in patients with CAD, whereas treatment with rosuvastatin had no impact on either let-7i or TLR4 levels [96]. Mason et al. [97] demonstrated that atorvastatin is more lipophilic and would therefore be more likely to permeate through cell membranes than rosuvastatin. It was already known that statins exert potent anti-atherosclerotic effects, which are mediated not only by their anti-hyperlipidaemic properties but also by their anti-inflammatory properties [55,56]. In particular, administration of atorvastatin attenuated the activation of TLR4 expression and its downstream pathway, including NF-κB signalling in an LPS-stimulated human cell line [57]. Atorvastatin has an antioxidant effect and can down-regulate NADPH oxidase activity [98]. An in vitro study has demonstrated that an active metabolite of atorvastatin inhibited membrane cholesterol domain formation as a function of oxidative stress, suggesting that atorvastatin may have the most effective antioxidant properties among the statins [97]. From these observations, treatment with atorvastatin affects let-7i expression in monocytes, thus down-regulating the TLR4 signalling pathway as an anti-atherosclerotic effect in CAD patients.

SIRT1-related miRNAs and miR-34a

The miRNA miR-34a binds directly to SIRT1 mRNA and regulates cell apoptosis by repressing SIRT1 in a cultured cell model, suggesting that miR-34a may be a negative regulator of SIRT1 [99,100]. Our previous study reported that levels of miR-34a in EPCs were higher in the CAD group than in control individuals, and were negatively correlated with SIRT1 protein levels [70]. A randomized clinical study showed the atorvastatin group to have markedly decreased miR-34a and increased SIRT1 levels and EPC counts, whereas the rosuvastatin group showed no change in these levels (Figure 6) [70]. In addition, treatment with atorvastatin up-regulated SIRT1 levels via repression of miR-34a compared with treatment with rosuvastatin in an in vitro study using cultured EPCs transfected with miR-34a [70]. Statins, in particular atorvastatin, up-regulate SIRT1 expression via inhibition of miR-34a in CAD, possibly contributing to the beneficial effects of statins on endothelial function in this disorder.

Effect of atorvastatin (n=35) and rosuvastatin (n=35) on number of EPCs and levels of miR-34a in patients with CAD

Figure 6
Effect of atorvastatin (n=35) and rosuvastatin (n=35) on number of EPCs and levels of miR-34a in patients with CAD

Representative examples are shown in (A). (B) Treatment with atorvastatin significantly increased the number of EPCs (CD34/KDR-positive cells) compared with rosuvastatin. (C) Treatment with atorvastatin decreased levels of miR-34a compared with rosuvastatin. (This Figure was reproduced from Tabuchi et al. [70].)

Figure 6
Effect of atorvastatin (n=35) and rosuvastatin (n=35) on number of EPCs and levels of miR-34a in patients with CAD

Representative examples are shown in (A). (B) Treatment with atorvastatin significantly increased the number of EPCs (CD34/KDR-positive cells) compared with rosuvastatin. (C) Treatment with atorvastatin decreased levels of miR-34a compared with rosuvastatin. (This Figure was reproduced from Tabuchi et al. [70].)

STATIN SIDE EFFECTS

When doctors prescribe statins for non-hyperlipidaemic patients with cardiovascular disease on the basis of the pleiotropic effects of statins, they have to be alert to the unwanted side effects of statin use, such as muscle pain, rhabdomyolysis, liver damage, digestive problems, rash or flushing, and neurological side effects

CONCLUSIONS

On the basis of our current knowledge, the cellular and molecular mechanisms of statins against coronary atherosclerosis appear to be well established. The LDL-independent pleiotropic effects of statins have a beneficial impact on endothelial senescence and immune response via miRNA biology (Figure 7).

Schematic view of beneficial effects of statins on coronary atherosclerosis

Figure 7
Schematic view of beneficial effects of statins on coronary atherosclerosis

VSMC, vascular smooth muscle cell.

Figure 7
Schematic view of beneficial effects of statins on coronary atherosclerosis

VSMC, vascular smooth muscle cell.

These cellular and molecular mechanisms of statins may identify new therapeutic targets, including vascular biology, and will facilitate the identification of patients with CAD who should get specific benefits from statin therapy. Therefore, early initiation of statin treatment may be indicated for primary or secondary prevention of CAD.

Further studies are needed to determine whether the cellular and molecular mechanisms of statins are related to clinical prognosis in patients with CAD.

Abbreviations

     
  • ACS

    acute coronary syndrome

  •  
  • CABG

    coronary artery bypass grafting

  •  
  • CAD

    coronary artery disease

  •  
  • CRP

    C-reactive protein

  •  
  • EPC

    endothelial progenitor cell

  •  
  • HMG-CoA

    3-hydroxy-3-methylglutaryl-coenzyme A

  •  
  • LDL-C

    low-density lipoprotein-cholesterol

  •  
  • IL

    interleukin

  •  
  • LPS

    lipopolysaccharide

  •  
  • MFI

    mean fluorescent intensity

  •  
  • NF-κB

    nuclear factor κB

  •  
  • PAMP

    pathogen-associated molecular pattern

  •  
  • SIRT1

    silent information regulator 1

  •  
  • TLR

    toll-like receptor

  •  
  • TNF-α

    tumour necrosis factor α

References

References
1
Libby
 
P.
 
Inflammation in atherosclerosis
Nature
2002
, vol. 
420
 (pg. 
868
-
874
)
[PubMed]
2
Weber
 
C.
Soehnlein
 
O.
 
ApoE controls the interface linking lipids and inflammation in atherosclerosis
J. Clin. Invest.
2011
, vol. 
121
 (pg. 
3825
-
3827
)
[PubMed]
3
Ascer
 
E.
Bertolami
 
M.C.
Venturinelli
 
M.L.
Buccheri
 
V.
Souza
 
J.
Nicolau
 
J.C.
Ramires
 
J.A.
Serrano
 
C.V.
 
Atorvastatin reduces proinflammatory markers in hypercholesterolemic patients
Atherosclerosis
2004
, vol. 
177
 (pg. 
161
-
166
)
[PubMed]
4
van de Ree
 
M.A.
Huisman
 
M.V.
Princen
 
H.M.
Meinders
 
A.E.
Kluft
 
C.
DALI study group
 
Strong decrease of high sensitivity C-reactive protein with high-dose atorvastatin in patients with type 2 diabetes mellitus
Atherosclerosis
2003
, vol. 
166
 (pg. 
129
-
135
)
[PubMed]
5
Järvisalo
 
M.J.
Toikka
 
J.O.
Vasankari
 
T.
Mikkola
 
J.
Viikari
 
J.S.
Hartiala
 
J.J.
Raitakari
 
O.T.
 
HMG CoA reductase inhibitors are related to improved systemic endothelial function in coronary artery disease
Atherosclerosis
1999
, vol. 
147
 (pg. 
237
-
242
)
[PubMed]
6
Dupuis
 
J.
Tardif
 
J.C.
Cernacek
 
P.
Théroux
 
P.
 
Cholesterol reduction rapidly improves endothelial function after acute coronary syndromes. The RECIFE (reduction of cholesterol in ischemia and function of the endothelium) trial
Circulation
1999
, vol. 
99
 (pg. 
3227
-
3233
)
[PubMed]
7
Schwartz
 
G.G.
Olsson
 
A.G.
Ezekowitz
 
M.D.
Ganz
 
P.
Oliver
 
M.F.
Waters
 
D.
Zeiher
 
A.
Chaitman
 
B.R.
Leslie
 
S.
Stern
 
T.
Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study investigators
 
Effects of atorvastatin on early recurrent ischemic events in acute coronary syndromes: the MIRACL study: a randomized controlled trial
JAMA
2001
, vol. 
285
 (pg. 
1711
-
1718
)
[PubMed]
8
Amarenco
 
P.
Goldstein
 
L.B.
Szarek
 
M.
Sillesen
 
H.
Rudolph
 
A.E.
Callahan
 
A.
Hennerici
 
M.
Simunovic
 
L.
Zivin
 
J.A.
Welch
 
K.M.
SPARCL investigators
 
Effects of intense low density lipoprotein cholesterol reduction in patients with stroke or transient ischemic attack: the Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial
Stroke
2007
, vol. 
38
 (pg. 
3198
-
3204
)
[PubMed]
9
Byington
 
R.P.
Davis
 
B.R.
Plehn
 
J.F.
White
 
H.D.
Baker
 
J.
Cobbe
 
S.M.
Shepherd
 
J.
 
Reduction of stroke events with pravastatin: the Prospective Pravastatin Pooling (PPP) Project
Circulation
2001
, vol. 
103
 (pg. 
387
-
392
)
[PubMed]
10
Kinlay
 
S.
Schwartz
 
G.G.
Olsson
 
A.G.
Rifai
 
N.
Sasiela
 
W.J.
Szarek
 
M.
Ganz
 
P.
Libby
 
P.
Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study investigators
 
Effect of atorvastatin on risk of recurrent cardiovascular events after an acute coronary syndrome associated with high soluble CD40 ligand in the Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) Study
Circulation
2004
, vol. 
110
 (pg. 
386
-
391
)
[PubMed]
11
Song
 
Y.B.
On
 
Y.K.
Kim
 
J.H.
Shin
 
D.H.
Kim
 
J.S.
Sung
 
J.
Lee
 
S.H.
Kim
 
W.S.
Lee
 
Y.T.
 
The effects of atorvastatin on the occurrence of postoperative atrial fibrillation after off-pump coronary artery bypass grafting surgery
Am. Heart J.
2008
, vol. 
156
 (pg. 
e9
-
e16
)
[PubMed]
12
Maggioni
 
A.P.
Fabbri
 
G.
Lucci
 
D.
Marchioli
 
R.
Franzosi
 
M.G.
Latini
 
R.
Nicolosi
 
G.L.
Porcu
 
M.
Cosmi
 
F.
Stefanelli
 
S.
, et al. , 
GISSI-HF investigators
 
Effects of rosuvastatin on atrial fibrillation occurrence: ancillary results of the GISSI-HF trial
Eur. Heart J.
2009
, vol. 
30
 (pg. 
2327
-
2336
)
[PubMed]
13
Ridker
 
P.M.
Danielson
 
E.
Fonseca
 
F.A.
Genest
 
J.
Gotto
 
A.M.
Kastelein
 
J.J.
Koenig
 
W.
Libby
 
P.
Lorenzatti
 
A.J.
MacFadyen
 
J.G.
, et al. , 
JUPITER study group
 
Rosuvastatin to prevent vascular events in men and women with elevated C reactive protein
N. Engl. J. Med.
2008
, vol. 
359
 (pg. 
2195
-
2207
)
[PubMed]
14
Moon
 
J.H.
Kang
 
S.B.
Park
 
J.S.
Lee
 
B.W.
Kang
 
E.S.
Ahn
 
C.W.
Lee
 
H.C.
Cha
 
B.S.
 
Up-regulation of hepatic low-density lipoprotein receptor-related protein 1: a possible novel mechanism of antiatherogenic activity of hydroxymethylglutaryl-coenzyme A reductase inhibitor atorvastatin and hepatic LRP1 expression
Metabolism
2011
, vol. 
60
 (pg. 
930
-
940
)
[PubMed]
15
Nakamura
 
H.
Arakawa
 
K.
Itakura
 
H.
Kitabatake
 
A.
Goto
 
Y.
Toyota
 
T.
Nakaya
 
N.
Nishimoto
 
S.
Muranaka
 
M.
Yamamoto
 
A.
, et al. , 
MEGA study group
 
Primary prevention of cardiovascular disease with pravastatin in Japan (MEGAStudy): a prospective randomised controlled trial
Lancet
2006
, vol. 
368
 (pg. 
1155
-
1163
)
[PubMed]
16
Downs
 
J.R.
Clearfield
 
M.
Weis
 
S.
Whitney
 
E.
Shapiro
 
D.R.
Beere
 
P.A.
Langendorfer
 
A.
Stein
 
E.A.
Kruyer
 
W.
Gotto
 
A.M.
 
Primary prevention of acute coronary events with lovastatin in men and women with average cholesterol levels: results of AFCAPS/TexCAPS. Air Force/Texas Coronary Atherosclerosis Prevention Study
JAMA
1998
, vol. 
279
 (pg. 
1615
-
1622
)
[PubMed]
17
Shepherd
 
J.
Cobbe
 
S.M.
Ford
 
I.
Isles
 
C.G.
Lorimer
 
A.R.
MacFarlane
 
P.W.
McKillop
 
J.H.
Packard
 
C.J.
West of Scotland Coronary Prevention Study Group
 
Prevention of coronary heart disease with pravastatin in men with hypercholesterolemia
N. Engl. J. Med.
1995
, vol. 
333
 (pg. 
1301
-
1307
)
[PubMed]
18
The Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) study group
Prevention of cardiovascular events and death with pravastatin in patients with coronary heart disease and a broad range of initial cholesterol levels
N. Engl. J. Med.
1998
, vol. 
339
 (pg. 
1349
-
1357
)
[PubMed]
19
The Scandinavian Simvastatin Survival Study (4S)
Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease
Lancet
1994
, vol. 
344
 (pg. 
1383
-
389
)
[PubMed]
20
Sever
 
P.S.
Dahlöf
 
B.
Poulter
 
N.R.
Wedel
 
H.
Beevers
 
G.
Caulfield
 
M.
Collins
 
R.
Kjeldsen
 
S.E.
Kristinsson
 
A.
McInnes
 
G.T.
, et al. , 
ASCOT investigators
 
Prevention of coronary and stroke events with atorvastatin in hypertensive patients who have average or lower-than-average cholesterol concentrations, in the Anglo-Scandinavian Cardiac Outcomes Trial–Lipid Lowering Arm (ASCOT-LLA): a multicentre randomised controlled trial
Lancet
2003
, vol. 
361
 (pg. 
1149
-
1158
)
[PubMed]
21
Sacks
 
F.M.
Pfeffer
 
M.A.
Moye
 
L.A.
Rouleau
 
J.L.
Rutherford
 
J.D.
Cole
 
T.G.
Brown
 
L.
Warnica
 
J.W.
Arnold
 
J.M.
Wun
 
C.C.
, et al. , 
Cholesterol and Recurrent Events Trial investigators
 
The effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels
N. Engl. J. Med.
1996
, vol. 
335
 (pg. 
1001
-
1009
)
[PubMed]
22
Cannon
 
C.P.
Braunwald
 
E.
McCabe
 
C.H.
Rader
 
D.J.
Rouleau
 
J.L.
Belder
 
R.
Joyal
 
S.V.
Hill
 
K.A.
Pfeffer
 
M.A.
Skene
 
A.M.
Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis in Myocardial Infarction 22 investigators
 
Intensive versus moderate lipid lowering with statins after acute coronary syndromes
N. Engl. J. Med.
2004
, vol. 
350
 (pg. 
1495
-
1504
)
[PubMed]
23
LaRosa
 
J.C.
Grundy
 
S.M.
Waters
 
D.D.
Shear
 
C.
Barter
 
P.
Fruchart
 
J.C.
Gotto
 
A.M.
Greten
 
H.
Kastelein
 
J.J.
Shepherd
 
J.
, et al. , 
Treating to New Targets (TNT) investigators
 
Intensive lipid lowering with atorvastatin in patients with stable coronary disease
N. Engl. J. Med.
2005
, vol. 
352
 (pg. 
1425
-
1435
)
[PubMed]
24
Ray
 
K.K.
Cannon
 
C.P.
McCabe
 
C.H.
Cairns
 
R.
Tonkin
 
A.M.
Sacks
 
F.M.
Jackson
 
G.
Braunwald
 
E.
PROVE IT–TIMI 22 investigators
 
Early and late benefits of high-dose atorvastatin in patients with acute coronary syndromes: results from the PROVE IT–TIMI 22 trial
J. Am. Coll. Cardiol.
2005
, vol. 
46
 (pg. 
1405
-
1410
)
[PubMed]
25
Kinlay
 
S.
Schwartz
 
G.G.
Olsson
 
A.G.
Rifai
 
N.
Szarek
 
M.
Waters
 
D.D.
Libby
 
P.
Ganz
 
P.
Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study investigators
 
Inflammation, statin therapy, and risk of stroke after an acute coronary syndrome in the MIRACL study
Arterioscler. Thromb. Vasc. Biol.
2008
, vol. 
28
 (pg. 
142
-
147
)
[PubMed]
26
Kinlay
 
S.
Schwartz
 
G.G.
Olsson
 
A.G.
Rifai
 
N.
Leslie
 
S.J.
Sasiela
 
W.J.
Szarek
 
M.
Libby
 
P.
Ganz
 
P.
 
Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering Study Investigators. High-dose atorvastatin enhances the decline in inflammatory markers in patients with acute coronary syndromes in the MIRACL study
Circulation
2003
, vol. 
108
 (pg. 
1560
-
1566
)
[PubMed]
27
Di Sciascio
 
G.
Patti
 
G.
Pasceri
 
V.
Gaspardone
 
A.
Colonna
 
G.
Montinaro
 
A.
 
Efficacy of atorvastatin reload in patients on chronic statin therapy undergoing percutaneous coronary intervention: results of the ARMYDA-RECAPTURE (Atorvastatin for Reduction of Myocardial Damage During Angioplasty) randomized trial
J. Am. Coll. Cardiol.
2009
, vol. 
54
 (pg. 
558
-
565
)
[PubMed]
28
Fichtlscherer
 
S.
Schmidt-Lucke
 
C.
Bojunga
 
S.
Rössig
 
L.
Heeschen
 
C.
Dimmeler
 
S.
Zeiher
 
A.M.
 
Differential effects of short-term lipid lowering with ezetimibe and statins on endothelial function in patients with CAD: clinical evidence for ‘pleiotropic’ functions of statin therapy
Eur. Heart J.
2006
, vol. 
27
 (pg. 
1182
-
1190
)
[PubMed]
29
Ford
 
E.S.
Giles
 
W.H.
Dietz
 
W.H.
 
Prevalence of the metabolic syndrome among US adults: findings from the third National Health and Nutrition Examination Survey
JAMA
2002
, vol. 
287
 (pg. 
356
-
359
)
[PubMed]
30
Malik
 
S.
Wong
 
N.D.
Franklin
 
S.S.
Kamath
 
T.V.
L'Italien
 
G.J.
Pio
 
J.R.
Williams
 
G.R.
 
Impact of the metabolic syndrome on mortality from coronary heart disease, cardiovascular disease, and all causes in United States adults
Circulation
2004
, vol. 
110
 (pg. 
1245
-
1250
)
[PubMed]
31
Halcox
 
J.P.
Schenke
 
W.H.
Zalos
 
G.
Mincemoyer
 
R.
Prasad
 
A.
Waclawiw
 
M.A.
Nour
 
K.R.
Quyyumi
 
A.A.
 
Prognostic value of coronary vascular endothelial dysfunction
Circulation
2002
, vol. 
106
 (pg. 
653
-
658
)
[PubMed]
32
Keaney
 
J.F.
Larson
 
M.G.
Vasan
 
R.S.
Wilson
 
P.W.
Lipinska
 
I.
Corey
 
D.
Massaro
 
J.M.
Sutherland
 
P.
Vita
 
J.A.
Benjamin
 
E.J.
Framingham Study
 
Obesity and systemic oxidative stress: clinical correlates of oxidative stress in the Framingham Study
Arterioscler. Thromb. Vasc. Biol.
2003
, vol. 
23
 (pg. 
434
-
439
)
[PubMed]
33
D'Agnillo
 
F.
Wood
 
F.
Porras
 
C.
Macdonald
 
V.W.
Alayash
 
A.I.
 
Effects of hypoxia and glutathione depletion on hemoglobin- and myoglobin-mediated oxidative stress toward endothelium
Biochim. Biophys. Acta
2000
, vol. 
1495
 (pg. 
150
-
159
)
[PubMed]
34
Berliner
 
J.A.
Territo
 
M.C.
Sevanian
 
A.
Ramin
 
S.
Kim
 
J.A.
Bamshad
 
B.
Esterson
 
M.
Fogelman
 
A.M.
 
Minimally modified LDL stimulates monocyte endothelial interaction
J. Clin. Invest.
1990
, vol. 
85
 (pg. 
1260
-
1266
)
[PubMed]
35
Aoki
 
M.
Nata
 
T.
Morishita
 
R.
Matsushita
 
H.
Nakagami
 
H.
Yamamoto
 
K.
Yamazaki
 
K.
Nakabayashi
 
M.
Ogihara
 
T.
Kaneda
 
Y.
 
Endothelial apoptosis induced by oxidative stress through activation of NF-kappaB: antiapoptotic effect of antioxidant agents on endothelial cells
Hypertension
2001
, vol. 
38
 (pg. 
48
-
55
)
[PubMed]
36
Asahara
 
T.
Murohara
 
T.
Sullivan
 
A.
Silver
 
M.
van der Zee
 
R.
Li
 
T.
Witzenbichler
 
B.
Schatteman
 
G.
Isner
 
J.M.
 
Isolation of putative progenitor endothelial cells for angiogenesis
Science
1997
, vol. 
275
 (pg. 
964
-
967
)
[PubMed]
37
Werner
 
N.
Kosiol
 
S.
Schiegl
 
T.
Ahlers
 
P.
Walenta
 
K.
Link
 
A.
Böhm
 
M.
Nickenig
 
G.
 
Circulating endothelial progenitor cells and cardiovascular outcomes
N. Engl. J. Med.
2005
, vol. 
353
 (pg. 
999
-
1007
)
[PubMed]
38
Shi
 
Q.
Rafii
 
S.
Wu
 
M.H.
Wijelath
 
E.S.
Yu
 
C.
Ishida
 
A.
Fujita
 
Y.
Kothari
 
S.
Mohle
 
R.
Sauvage
 
L.R.
, et al 
Evidence for circulating bone marrow-derived endothelial cells
Blood
1998
, vol. 
92
 (pg. 
362
-
367
)
[PubMed]
39
Walter
 
D.H.
Rittig
 
K.
Bahlmann
 
F.H.
Kirchmair
 
R.
Silver
 
M.
Murayama
 
T.
Nishimura
 
H.
Losordo
 
D.W.
Asahara
 
T.
Isner
 
J.M.
 
Statin therapy accelerates reendothelialization: a novel effect involving mobilization and incorporation of bone marrow-derived endothelial progenitor cells
Circulation
2002
, vol. 
105
 (pg. 
3017
-
3024
)
[PubMed]
40
Rafii
 
S.
Lyden
 
D.
 
Therapeutic stem and progenitor cell transplantation for organ vascularization and regeneration
Nat. Med.
2003
, vol. 
9
 (pg. 
702
-
712
)
[PubMed]
41
Blackburn
 
E.H.
 
Switching and signaling at the telomere
Cell
2001
, vol. 
106
 (pg. 
661
-
673
)
[PubMed]
42
Satoh
 
M.
Ishikawa
 
Y.
Takahashi
 
Y.
Itoh
 
T.
Minami
 
Y.
Nakamura
 
M.
 
Association between oxidative DNA damage and telomere shortening in circulating endothelial progenitor cells obtained from metabolic syndrome patients with coronary artery disease
Atherosclerosis
2008
, vol. 
198
 (pg. 
347
-
353
)
[PubMed]
43
Spyridopoulos
 
I.
Haendeler
 
J.
Urbich
 
C.
Brummendorf
 
T.H.
Oh
 
H.
Schneider
 
M.D.
Zeiher
 
A.M.
Dimmeler
 
S.
 
Statins enhance migratory capacity by upregulation of the telomere repeat-binding factor TRF2 in endothelial progenitor cells
Circulation
2004
, vol. 
110
 (pg. 
3136
-
3142
)
[PubMed]
44
Nissen
 
S.E.
Tuzcu
 
E.M.
Schoenhagen
 
P.
Brown
 
B.G.
Ganz
 
P.
Vogel
 
R.A.
Crowe
 
T.
Howard
 
G.
Cooper
 
C.J.
Brodie
 
B.
, et al. , 
REVERSAL investigators
 
Effect of intensive compared with moderate lipid-lowering therapy on progression of coronary atherosclerosis: a randomized controlled trial
JAMA
2004
, vol. 
291
 (pg. 
1071
-
1080
)
[PubMed]
45
Satoh
 
M.
Minami
 
Y.
Takahashi
 
Y.
Tabuchi
 
T.
Itoh
 
T.
Nakamura
 
M.
 
Effect of intensive lipid-lowering therapy on telomere erosion in endothelial progenitor cells obtained from patients with coronary artery disease
Clin. Sci.
2009
, vol. 
116
 (pg. 
827
-
835
)
[PubMed]
46
Takeda
 
K.
Kaisho
 
T.
Akira
 
S.
 
Toll-like receptors
Annu. Rev. Immunol.
2003
, vol. 
21
 (pg. 
335
-
376
)
[PubMed]
47
Medzhitov
 
R.
 
Toll-like receptors and innate immunity
Nat. Rev. Immunol.
2001
, vol. 
1
 (pg. 
135
-
145
)
[PubMed]
48
Akira
 
S.
Takeda
 
K.
Kaisho
 
T.
 
Toll-like receptors: critical proteins linking innate and acquired immunity
Nat. Immunol.
2001
, vol. 
2
 (pg. 
675
-
680
)
[PubMed]
49
Medzhitov
 
R.
Preston-Hurlburt
 
P.
Janeway
 
C.A.
 
A human homologue of the Drosophila Toll protein signals activation of adaptive immunity
Nature
1997
, vol. 
388
 (pg. 
394
-
397
)
[PubMed]
50
Modlin
 
R.L.
Brightbill
 
H.D.
Godowski
 
P.
 
The Toll of innate immunity on microbial pathogens
N. Engl. J. Med.
1999
, vol. 
340
 (pg. 
1834
-
1835
)
[PubMed]
51
Satoh
 
M.
Shimoda
 
Y.
Maesawa
 
C.
Akatsu
 
T.
Ishikawa
 
Y.
Minami
 
Y.
Itoh
 
T.
Nakamura
 
M.
 
Activated toll-like receptor 4 in monocytes is associated with heart failure after acute myocardial infarction
Int. J. Cardiol.
2006
, vol. 
109
 (pg. 
226
-
234
)
[PubMed]
52
Satoh
 
M.
Shimoda
 
Y.
Akatsu
 
T.
Ishikawa
 
Y.
Minami
 
Y.
Nakamura
 
M.
 
Elevated circulating levels of heat shock protein 70 are related to systemic inflammatory reaction through monocyte Toll signal in patients with heart failure after acute myocardial infarction
Eur. J. Heart Fail.
2006
, vol. 
8
 (pg. 
810
-
815
)
[PubMed]
53
Ishikawa
 
Y.
Satoh
 
M.
Itoh
 
T.
Minami
 
Y.
Takahashi
 
Y.
Akamura
 
M.
 
Local expression of Toll-like receptor 4 at the site of ruptured plaques in patients with acute myocardial infarction
Clin. Sci.
2008
, vol. 
115
 (pg. 
133
-
140
)
[PubMed]
54
Michelsen
 
K.S.
Wong
 
M.H.
Shah
 
P.K.
Zhang
 
W.
Yano
 
J.
Doherty
 
T.M.
Akira
 
S.
Rajavashisth
 
T.B.
Arditi
 
M.
 
Lack of Toll-like receptor 4 or myeloid differentiation factor 88 reduces atherosclerosis and alters plaque phenotype in mice deficient in apolipoprotein E
Proc. Natl. Acad. Sci. U.S.A.
2004
, vol. 
101
 (pg. 
10679
-
10684
)
[PubMed]
55
Nissen
 
S. E.
Tuzcu
 
E.M.
Schoenhagen
 
P.
Crowe
 
T.
Sasiela
 
W.J.
Tsai
 
J.
Orazem
 
J.
Magorien
 
R.D.
O'Shaughnessy
 
C.
Ganz
 
P.
Reversal of Atherosclerosis with Aggressive Lipid Lowering (REVERSAL) investigators
 
Statin therapy, LDL cholesterol, C-reactive protein, and coronary artery disease
N. Engl. J. Med.
2005
, vol. 
352
 (pg. 
29
-
38
)
[PubMed]
56
Ridker
 
P.M.
Cannon
 
C.P.
Morrow
 
D.
Rifai
 
N.
Rose
 
L.M.
McCabe
 
C.H.
Pfeffer
 
M.A.
Braunwald
 
E.
Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis in Myocardial Infarction 22 (PROVE IT–TIMI 22) investigators
 
C-reactive protein levels and outcomes after statin therapy
N. Engl. J. Med.
2005
, vol. 
352
 (pg. 
20
-
28
)
[PubMed]
57
Yilmaz
 
A.
Reiss
 
C.
Weng
 
A.
Cicha
 
I.
Stumpf
 
C.
Steinkasserer
 
A.
Daniel
 
W.G.
Garlichs
 
C.D.
 
Differential effects of statins on relevant functions of human monocyte-derived dendritic cells
J. Leukoc. Biol.
2006
, vol. 
79
 (pg. 
529
-
538
)
[PubMed]
58
Moutzouri
 
E.
Tellis
 
C.C.
Rousouli
 
K.
Liberopoulos
 
E.N.
Milionis
 
H.J.
Elisaf
 
M.S.
Tselepis
 
A.D.
 
Effect of simvastatin or its combination with ezetimibe on Toll-like receptor expression and lipopolysaccharide-induced cytokine production in monocytes of hypercholesterolemic patients
Atherosclerosis
2012
, vol. 
225
 (pg. 
381
-
387
)
[PubMed]
59
Lusis
 
A.J.
 
Atherosclerosis
Nature
2000
, vol. 
407
 (pg. 
233
-
241
)
[PubMed]
60
Brandes
 
R.P.
Fleming
 
I.
Busse
 
R.
 
Endothelial aging
Cardiovasc. Res.
2005
, vol. 
66
 (pg. 
286
-
294
)
[PubMed]
61
Kudo
 
F.A.
Warycha
 
B.
Juran
 
P.J.
Asada
 
H.
Teso
 
D.
Aziz
 
F.
Frattini
 
J.
Sumpio
 
B.E.
Nishibe
 
T.
Cha
 
C.
, et al 
Differential responsiveness of early- and late-passage endothelial cells to shear stress
Am. J. Surg.
2005
, vol. 
190
 (pg. 
763
-
769
)
[PubMed]
62
Minamino
 
T.
Komuro
 
I.
 
Vascular cell senescence: contribution to atherosclerosis
Circ. Res.
2007
, vol. 
100
 (pg. 
15
-
26
)
[PubMed]
63
Frye
 
R.A.
 
Phylogenetic classification of prokaryotic and eukaryotic Sir2-like proteins
Biochem. Biophys. Res. Commun.
2000
, vol. 
273
 (pg. 
793
-
798
)
[PubMed]
64
Braunstein
 
M.
Rose
 
A.B.
Holmes
 
S.G.
Allis
 
C.D.
Broach
 
J.R.
 
Transcriptional silencing in yeast is associated with reduced nucleosome acetylation
Genes Dev.
1993
, vol. 
7
 (pg. 
592
-
604
)
[PubMed]
65
Potente
 
M.
Dimmeler
 
S.
 
Emerging roles of SIRT1 in vascular endothelial homeostasis
Cell Cycle
2008
, vol. 
7
 (pg. 
2117
-
2122
)
[PubMed]
66
Ota
 
H.
Akishita
 
M.
Eto
 
M.
Iijima
 
K.
Kaneki
 
M.
Ouchi
 
Y.
 
Sirt1 modulates premature senescence-like phenotype in human endothelial cells
J. Mol. Cell. Cardiol.
2007
, vol. 
43
 (pg. 
571
-
579
)
[PubMed]
67
Ota
 
H.
Eto
 
M.
Kano
 
M.R.
Kahyo
 
T.
Setou
 
M.
Ogawa
 
S.
Iijima
 
K.
Akishita
 
M.
Ouchi
 
Y.
 
Induction of endothelial nitric oxide synthase, SIRT1, and catalase by statins inhibits endothelial senescence through the Akt pathway
Arterioscler. Thromb. Vasc. Biol.
2010
, vol. 
30
 (pg. 
2205
-
2211
)
[PubMed]
68
Csiszar
 
A.
Labinskyy
 
N.
Jimenez
 
R.
Pinto
 
J.T.
Ballabh
 
P.
Losonczy
 
G.
Pearson
 
K.J.
de Cabo
 
R.
Ungvari
 
Z.
 
Anti-oxidative and anti-inflammatory vasoprotective effects of caloric restriction in aging: role of circulating factors and SIRT1
Mech. Ageing Dev.
2009
, vol. 
130
 (pg. 
518
-
527
)
[PubMed]
69
Yang
 
J.
Wang
 
N.
Zhu
 
Y.
Feng
 
P.
 
Roles of SIRT1 in high glucose-induced endothelial impairment: association with diabetic atherosclerosis
Arch. Med. Res.
2011
, vol. 
42
 (pg. 
354
-
360
)
[PubMed]
70
Tabuchi
 
T.
Satoh
 
M.
Itoh
 
T.
Nakamura
 
M.
 
MicroRNA-34a regulates the longevity-associated protein SIRT1 in coronary artery disease: effect of statins on SIRT1 and microRNA-34a expression
Clin. Sci.
2012
, vol. 
123
 (pg. 
161
-
171
)
[PubMed]
71
Satoh
 
M.
Ishikawa
 
Y.
Minami
 
Y.
Takahashi
 
Y.
Nakamura
 
M.
 
Role of Toll like receptor signaling pathway in ischemic coronary artery disease
Front. Biosci.
2008
, vol. 
13
 (pg. 
6708
-
6715
)
[PubMed]
72
Kawamura
 
A.
Baitsch
 
D.
Telgmann
 
R.
Feuerborn
 
R.
Weissen-Plenz
 
G.
Hagedorn
 
C.
Saku
 
K.
Brand-Herrmann
 
S.M.
von Eckardstein
 
A.
Assmann
 
G.
, et al 
Apolipoprotein E interrupts interleukin-1beta signaling in vascular smooth muscle cells
Arterioscler. Thromb. Vasc. Biol.
2007
, vol. 
27
 (pg. 
1610
-
1617
)
[PubMed]
73
Yearley
 
J.H.
Xia
 
D.
Pearson
 
C.B.
Carville
 
A.
Shannon
 
R.P.
Mansfield
 
K.G.
 
Interleukin-18 predicts atherosclerosis progression in SIV-infected and uninfected rhesus monkeys (Macaca mulatta) on a high-fat/high-cholesterol diet
Lab. Invest.
2009
, vol. 
89
 (pg. 
657
-
667
)
[PubMed]
74
Galea
 
J.
Armstrong
 
J.
Gadsdon
 
P.
Holden
 
H.
Francis
 
S.E.
Holt
 
C.M.
 
Interleukin-1 beta in coronary arteries of patients with ischemic heart disease
Arterioscler. Thromb. Vasc. Biol.
1996
, vol. 
16
 (pg. 
1000
-
1006
)
[PubMed]
75
Blankenberg
 
S.
Tiret
 
L.
Bickel
 
C.
Peetz
 
D.
Cambien
 
F.
Meyer
 
J.
Rupprecht
 
H.J.
AtheroGene investigators
 
Interleukin-18 is a strong predictor of cardiovascular death in stable and unstable angina
Circulation
2002
, vol. 
106
 (pg. 
24
-
30
)
[PubMed]
76
Kirii
 
H.
Niwa
 
T.
Yamada
 
Y.
Wada
 
H.
Saito
 
K.
Iwakura
 
Y.
Asano
 
M.
Moriwaki
 
H.
Seishima
 
M.
 
Lack of interleukin-1beta decreases the severity of atherosclerosis in ApoE-deficient mice
Arterioscler. Thromb. Vasc. Biol.
2003
, vol. 
23
 (pg. 
656
-
660
)
[PubMed]
77
Elhage
 
R.
Jawien
 
J.
Rudling
 
M.
Ljunggren
 
H.G.
Takeda
 
K.
Akira
 
S.
Bayard
 
F.
Hansson
 
G.K.
 
Reduced atherosclerosis in interleukin-18 deficient apolipoprotein E-knockout mice
Cardiovasc. Res.
2003
, vol. 
59
 (pg. 
234
-
240
)
[PubMed]
78
Leemans
 
J.C.
Cassel
 
S.L.
Sutterwala
 
F.S.
 
Sensing damage by the NLRP3 inflammasome
Immunol. Rev.
2011
, vol. 
243
 (pg. 
152
-
162
)
[PubMed]
79
Schroder
 
K.
Zhou
 
R.
Tschopp
 
J.
 
The NLRP3 inflammasome: a sensor for metabolic danger?
Science
2010
, vol. 
327
 (pg. 
296
-
300
)
[PubMed]
80
Tschopp
 
J.
Schroder
 
K.
 
NLRP3 inflammasome activation: the convergence of multiple signalling pathways on ROS production?
Nat. Rev. Immunol.
2010
, vol. 
10
 (pg. 
210
-
215
)
[PubMed]
81
Schroder
 
K.
Tschopp
 
J.
 
The inflammasones
Cell
2010
, vol. 
140
 (pg. 
821
-
832
)
[PubMed]
82
Rajamäki
 
K.
Lappalainen
 
J.
Oörni
 
K.
Välimäki
 
E.
Matikainen
 
S.
Kovanen
 
P.T.
Eklund
 
K.K.
 
Cholesterol crystals activate the NLRP3 inflammasome in human macrophages: a novel link between cholesterol metabolism and inflammation
PLoS One
2010
, vol. 
5
 pg. 
e11765
 
[PubMed]
83
Satoh
 
M.
Tabuchi
 
T.
Itoh
 
T.
Nakamura
 
M.
 
NLRP3 inflammasome activation in coronary artery disease: results from prospective and randomized study of treatment with atorvastatin or rosuvastatin
Clin. Sci.
2014
, vol. 
126
 (pg. 
233
-
241
)
[PubMed]
84
Bartel
 
D.P.
 
MicroRNAs: genomics, biogenesis, mechanism, and function
Cell
2004
, vol. 
116
 (pg. 
281
-
97
)
[PubMed]
85
Kim
 
V.N.
 
Small RNAs: classification, biogenesis, and function
Mol. Cells
2005
, vol. 
19
 (pg. 
1
-
15
)
[PubMed]
86
Felli
 
N.
Fontana
 
L.
Pelosi
 
E.
Botta
 
R.
Bonci
 
D.
Facchiano
 
F.
Liuzzi
 
F.
Lulli
 
V.
Morsilli
 
O.
Santoro
 
S.
, et al 
MicroRNAs 221 and 222 inhibit normal erythropoiesis and erythroleukemic cell growth via kit receptor down-modulation
Proc. Natl. Acad. Sci. U.S.A.
2005
, vol. 
102
 (pg. 
18081
-
18086
)
[PubMed]
87
Tuccoli
 
A.
Poliseno
 
L.
Rainaldi
 
G.
 
miRNAs regulate miRNAs: coordinated transcriptional and post-transcriptional regulation
Cell Cycle
2006
, vol. 
5
 (pg. 
2473
-
2476
)
[PubMed]
88
Suarez
 
Y.
Fernandez-Hernando
 
C.
Pober
 
J.S.
Sessa
 
W.C.
 
Dicer dependent microRNAs regulate gene expression and functions in human endothelial cells
Circ. Res.
2007
, vol. 
100
 (pg. 
1164
-
1173
)
[PubMed]
89
Poliseno
 
L.
Tuccoli
 
A.
Mariani
 
L.
Evangelista
 
M.
Citti
 
L.
Woods
 
K.
Mercatanti
 
A.
Hammond
 
S.
Rainaldi
 
G.
 
MicroRNAs modulate the angiogenic properties of HUVECs
Blood
2006
, vol. 
108
 (pg. 
3068
-
3071
)
[PubMed]
90
Lewis
 
B.P.
Burge
 
C.B.
Bartel
 
DP.
 
Conserved seed pairing, often flanked by adenosines, indicates that thousands of human genes are microRNA targets
Cell
2005
, vol. 
120
 (pg. 
15
-
20
)
[PubMed]
91
Calin
 
G.A.
Sevignani
 
C.
Dumitru
 
C.D.
Hyslop
 
T.
Noch
 
E.
Yendamuri
 
S.
Shimizu
 
M.
Rattan
 
S.
Bullrich
 
F.
Negrini
 
M.
, et al 
Human microRNA genes are frequently located at fragile sites and genomic regions involved in cancers
Proc. Natl. Acad. Sci. U.S.A.
2004
, vol. 
101
 (pg. 
2999
-
3004
)
[PubMed]
92
Altuvia
 
Y.
Landgraf
 
P.
Lithwick
 
G.
Elefant
 
N.
Pfeffer
 
S.
Aravin
 
A.
Brownstein
 
M.J.
Tuschl
 
T.
Margalit
 
H.
 
Clustering and conservation patterns of human microRNAs
Nucleic Acids Res.
2005
, vol. 
33
 (pg. 
2697
-
2706
)
[PubMed]
93
Minami
 
Y.
Satoh
 
M.
Maesawa
 
C.
Takahashi
 
Y.
Tabuchi
 
T.
Itoh
 
T.
Nakamura
 
M.
 
Effect of atorvastatin on microRNA 221/222 expression in endothelial progenitor cells obtained from patients with coronary artery disease
Eur. J. Clin. Invest.
2009
, vol. 
39
 (pg. 
359
-
367
)
[PubMed]
94
Chen
 
X.M.
Splinter
 
P.L.
O'Hara
 
S.P.
LaRusso
 
N.F.
 
A cellular micro-RNA, let-7i, regulates Toll-like receptor 4 expression and contributes to cholangiocyte immune responses against Cryptosporidium parvum infection
J. Biol. Chem.
2007
, vol. 
282
 (pg. 
28929
-
28938
)
[PubMed]
95
O'Hara
 
S.P.
Splinter
 
P.L.
Gajdos
 
G.B.
Trussoni
 
C.E.
Fernandez-Zapico
 
M.E.
Chen
 
X.M.
LaRusso
 
N.F.
 
NFkappaB p50-CCAAT/enhancer-binding protein beta (C/EBPbeta)-mediated transcriptional repression of microRNA let-7i following microbial infection
J. Biol. Chem.
2010
, vol. 
285
 (pg. 
216
-
225
)
[PubMed]
96
Satoh
 
M.
Tabuchi
 
T.
Minami
 
Y.
Takahashi
 
Y.
Itoh
 
T.
Nakamura
 
M.
 
Expression of let-7i is associated with Toll-like receptor 4 signal in coronary artery disease: effect of statins on let-7i and Toll-like receptor 4 signal
Immunobiology
2012
, vol. 
217
 (pg. 
533
-
539
)
[PubMed]
97
Mason
 
R.P.
Walter
 
M.F.
Day
 
C.A.
Jacob
 
R.F.
 
Active metabolite of atorvastatin inhibits membrane cholesterol domain formation by an antioxidant mechanism
J. Biol. Chem.
2006
, vol. 
281
 (pg. 
9337
-
9345
)
[PubMed]
98
Wassmann
 
S.
Laufs
 
U.
Muller
 
K.
Konkol
 
C.
Ahlbory
 
K.
Baumer
 
A.T.
Bäumer
 
A.T.
Linz
 
W.
Böhm
 
M.
Nickenig
 
G.
 
Cellular antioxidant effects of atorvastatin in vitro and in vivo
Arterioscler. Thromb. Vasc. Biol.
2002
, vol. 
22
 (pg. 
300
-
305
)
[PubMed]
99
Yamakuchi
 
M.
Ferlito
 
M.
Lowenstein
 
CJ.
 
miR-34a repression of SIRT1 regulates apoptosis
Proc. Natl. Acad. Sci. U.S.A.
2008
, vol. 
105
 (pg. 
13421
-
13426
)
[PubMed]
100
Yamakuchi
 
M.
Lowenstein
 
C.J.
 
MiR-34, SIRT1 and p53: the feedback loop
Cell Cycle
2009
, vol. 
8
 (pg. 
712
-
715
)
[PubMed]