Pravastatin has cholesterol-lowering independent effects on the artery wall of atherosclerotic monkeys

Regulating NETs contributes to a novel antiatherogenic effect of MTHSWD via inhibiting endothelial injury and apoptosis

Neutrophil extracellular traps (NETs) are implicated in the occurrence and progression of atherosclerosis (AS), which can result in adverse cardiovascular events. We investigated the potential mechanism of action of Modified Taohong Siwu Decoction (MTHSWD) against AS based on its effect on NETs. A model of unstable plaque in AS was established by tandem stenosis (TS) of the right common carotid artery in ApoE-/- mice combined with a western diet (WD). The research found that MTHSWD reduced the weight of mice with AS to varying degrees, and significantly decreased the levels of plasma total cholesterol (TC) and triglycerides (TG). Meanwhile, we found that MTHSWD not only significantly improved cardiac EF, FS, cardiac hypertrophy, and ventricular remodeling, but also ameliorated the silent and depressed hypoactivity state caused by AS in ApoE-/- mice. Additionally, the study revealed that MTHSWD improved the severity of AS, protected the vascular structure, increased plaque stability and vessel patency. It also significantly reduced vascular cell apoptosis, platelet aggregation, and the presence of inflammatory cells such as neutrophils (NEUs), as well as the expression of neutrocyte elastase (NE) and myeloperoxidase (MPO), which are components of NETs. Subsequently, NEUs studies have shown that MTHSWD not only significantly reduces the dsDNA content of NETs, but also lowers the expression of NETs components NE and citH3. NETs treating the human umbilical vein endothelial cells (HUVECs) demonstrated that NETs differentially increased the protein expression of endothelial inflammatory adhesion factors CD62P, VCAM-1 and ICAM-1, while significantly decreasing the viability of HUVECs. Pharmacological treatment discovered that MTHSWD significantly improved HUVECs viability impaired by NETs, and promoted the growth and proliferation of endothelial cells. Furthermore, it significantly reduced early and late apoptosis of HUVECs caused by NETs, decreased the expression of pro-apoptotic proteins BAX and Cleaved-Caspase-3, and increased the expression of anti-apoptotic protein Bcl-2. Thus, study suggests that MTHSWD may improve body weight, lipid levels, cardiac function, vigour, and the severity of AS in ApoE-/- AS mice. The novel effect of MTHSWD against AS may be attributed to the inhibition of endothelial injury and apoptosis through the regulation of NETs. This, in turn, reduces the levels of platelets, inflammatory cells, and components of NETs in AS plaques, achieving a benign cycle that protects endothelial cells and vascular structure and function. This result provides some clues and evidence for studying the mechanism of action and clinical application of MTHSWD and its active ingredients against AS.

Undertreatment or Overtreatment With Statins: Where Are We?

Statins, in addition to healthy lifestyle interventions, are the cornerstone of lipid-lowering therapy. Other low-density lipoprotein (LDL)-lowering drugs include ezetimibe, bile acid sequestrants, and PCSK9 inhibitors. As new evidence emerges from new clinical trials, therapeutic goals change, leading to renewed clinical guidelines. Nowadays, LDL goals are getting lower, leading to the "lower is better" paradigm in LDL-cholesterol (LDL-C) management. Several observational studies have shown that LDL-C control in real life is suboptimal in both primary and secondary preventions. It is critical to enhance the adherence to guideline recommendations through shared decision-making between clinicians and patients, with patient engagement in selecting interventions based on individual values, preferences, and associated conditions and comorbidities. This narrative review summarizes the evidence regarding the benefits of lipid-lowering drugs in reducing cardiovascular events, the pleiotropic effect of statins, real-world data on overtreatment and undertreatment of lipid-lowering therapies, and the changing LDL-C in targets in the clinical guidelines of dyslipidemias over the years.

Tropoelastin: an in vivo imaging marker of dysfunctional matrix turnover during abdominal aortic dilation

Aims

Dysfunctional matrix turnover is present at sites of abdominal aortic aneurysm (AAA) and leads to the accumulation of monomeric tropoelastin rather than cross-linked elastin. We used a gadolinium-based tropoelastin-specific magnetic resonance contrast agent (Gd-TESMA) to test whether quantifying regional tropoelastin turnover correlates with aortic expansion in a murine model. The binding of Gd-TESMA to excised human AAA was also assessed.

Methods and results

We utilized the angiotensin II (Ang II)-infused apolipoprotein E gene knockout (ApoE^-/-) murine model of aortic dilation and performed in vivo imaging of tropoelastin by administering Gd-TESMA followed by late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) and T₁ mapping at 3 T, with subsequent ex vivo validation. In a cross-sectional study (n = 66; control = 11, infused = 55) we found that Gd-TESMA enhanced MRI was elevated and confined to dilated aortic segments (control: _LGE=0.13 ± 0.04 mm², control _R1= 1.1 ± 0.05 s^-1 vs. dilated _LGE=1.0 ± 0.4 mm², dilated _R1 =2.4 ± 0.9 s^-1) and was greater in segments with medium (8.0 ± 3.8 mm³) and large (10.4 ± 4.1 mm³) compared to small (3.6 ± 2.1 mm³) vessel volume. Furthermore, a proof-of-principle longitudinal study (n = 19) using Gd-TESMA enhanced MRI demonstrated a greater proportion of tropoelastin: elastin expression in dilating compared to non-dilating aortas, which correlated with the rate of aortic expansion. Treatment with pravastatin and aspirin (n = 10) did not reduce tropoelastin turnover (0.87 ± 0.3 mm² vs. 1.0 ± 0.44 mm²) or aortic dilation (4.86 ± 2.44 mm³ vs. 4.0 ± 3.6 mm³). Importantly, Gd-TESMA-enhanced MRI identified accumulation of tropoelastin in excised human aneurysmal tissue (n = 4), which was confirmed histologically.

Conclusion

Tropoelastin MRI identifies dysfunctional matrix remodelling that is specifically expressed in regions of aortic aneurysm or dissection and correlates with the development and rate of aortic expansion. Thus, it may provide an additive imaging marker to the serial assessment of luminal diameter for surveillance of patients at risk of or with established aortopathy.

Sustained Focal Vascular Inflammation Accelerates Atherosclerosis in Remote Arteries

OBJECTIVE

Evidence from preclinical and clinical studies has demonstrated that myocardial infarction promotes atherosclerosis progression. The impact of focal vascular inflammation on the progression and phenotype of remote atherosclerosis remains unknown. Approach and Results: We used a novel ApoE^-/- knockout mouse model of sustained arterial inflammation, initiated by mechanical injury in the abdominal aorta. Using serial in vivo molecular MRI and ex vivo histology and flow cytometry, we demonstrate that focal arterial inflammation triggered by aortic injury, accelerates atherosclerosis in the remote brachiocephalic artery. The brachiocephalic artery atheroma had distinct histological features including increased plaque size, plaque permeability, necrotic core to collagen ratio, infiltration of more inflammatory monocyte subsets, and reduced collagen content. We also found that arterial inflammation following focal vascular injury evoked a prolonged systemic inflammatory response manifested as a persistent increase in serum IL-6 (interleukin 6). Finally, we demonstrate that 2 therapeutic interventions-pravastatin and minocycline-had distinct anti-inflammatory effects at the plaque and systemic level.

CONCLUSIONS

We show for the first time that focal arterial inflammation in response to vascular injury enhances systemic vascular inflammation, accelerates remote atheroma progression and induces plaques more inflamed, lipid-rich, and collagen-poor in the absence of ischemic myocardial injury. This inflammatory cascade is modulated by pravastatin and minocycline treatments, which have anti-inflammatory effects at both plaque and systemic levels that mitigate atheroma progression.

Effects of NIX-mediated mitophagy on ox-LDL-induced macrophage pyroptosis in atherosclerosis

Pyroptosis is a form of cell death that is uniquely dependent on caspase-1. Pyroptosis involved in oxidized low-density lipoprotein (ox-LDL)-induced human macrophage death through the promotion of caspase-1 activation is important for the formation of unstable plaques in atherosclerosis. The mitochondrial outer membrane protein NIX directly interacts with microtubule-associated protein 1 light chain 3 (LC3). Although we previously showed that NIX-mediated mitochondrial autophagy is involved in the clearance of damaged mitochondria, how NIX contributes to ox-LDL-induced macrophage pyroptosis remains unknown. Here, immunoperoxidase staining Nix expression decreased in human atherosclerosis. When we silenced NIX expression in murine macrophage cell, active caspase-1, and mature interleukin-1β expression levels were increased and LC3 was reduced. In addition, LDH release and acridine orange and ethidium bromide staining indicated that damage to macrophage cell membranes induced by ox-LDL was substantially worse. Moreover, intracellular reactive oxygen species and NLRP3 inflammasome levels increased. Taken together, these results demonstrated that NIX inhibits ox-LDL-induced macrophage pyroptosis via autophagy in atherosclerosis.

Comparative effects of atorvastatin 80 mg and rosuvastatin 40 mg on the levels of serum endocan, chemerin, and galectin-3 in patients with acute myocardial infarction

OBJECTIVE

Endocan, chemerin, and galectin-3 are discrete biomarkers associated with cardiovascular diseases and acting through different pathophysiological pathways. The aim of this study is to investigate and compare the effects of high doses of atorvastatin and rosuvastatin on serum endocan, chemerin, and galectin-3 levels in patients with acute myocardial infarction (AMI).

METHODS

Sixty-three patients with AMI were randomized to receive atorvastatin (80 mg/day) or rosuvastatin (40 mg/day) after percutaneous revascularization. Serum levels of endocan, chemerin, and galectin-3 were evaluated at baseline and after 4-week therapy.

RESULTS

Endocan levels were not decreased statistically significantly with atorvastatin 80 mg, but rosuvastatin 40 mg markedly decreased the levels of endocan according to baseline [from 110.27 (86.03-143.69) pg/mL to 99.22 (78.30-122.87) pg/mL with atorvastatin 80 mg and from 110.73 (77.28-165.22) pg/mL to 93.40 (70.48-115.13) pg/mL with rosuvastatin 40 mg, p=0.242 for atorvastatin 80 mg and p=0.014 for rosuvastatin 40 mg]. Chemerin levels significantly decreased in both groups according to baseline [from 264.90 (196.00-525.95) ng/mL to 135.00 (105.95-225.65) ng/mL with atorvastatin 80 mg and from 309.95 (168.87-701.27) ng/mL to 121.25 (86.60-212.65) ng/mL with rosuvastatin 40 mg, p<0.001, respectively, for both groups]. Galectin-3 levels did not change markedly with atorvastatin 80 mg, but they decreased with rosuvastatin 40 mg [from 17.00 (13.10-22.25) ng/mL to 19.30 (15.25-23.45) ng/mL with atorvastatin 80 mg, p=0.721, and from 18.25 (12.82-23.82) ng/mL to 16.60 (10.60-20.15) ng/mL with rosuvastatin 40 mg, p=0.074]. There were no significant between-group differences in terms of absolute and percentage changes of endocan, chemerin, and galectin-3 at 4 weeks.

CONCLUSION

We reported that both statins similarly decreased the endocan levels, whereas rosuvastatin seems to have more prominent effects on the reduction of the chemerin and galectin-3 levels in patients with AMI.

Rapid improvement in carotid adventitial angiogenesis and plaque neovascularization after rosuvastatin therapy in statin treatment-naïve subjects

BACKGROUND

Statin therapy can improve plaque stability. However, the time course of effects of statin on adventitial angiogenesis and plaque neovascularization has not been studied.

OBJECTIVE

The objective of the study was to investigate whether statin therapy reduces plaque neovascularization, associated with adventitial angiogenesis, over 24 months as assessed by using carotid dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

METHODS

Forty-three lipid treatment-naïve subjects with asymptomatic carotid atherosclerosis received rosuvastatin (5-20 mg/d) to lower low-density lipoprotein cholesterol to <80 mg/dL for 24 months. Carotid DCE-MRI was performed at baseline, 3, 12 and 24 months. Vascularity (V_p = fractional plasma volume) and vascular permeability (K^trans = transfer constant) derived from kinetic modeling of DCE-MRI were measured in both adventitia and plaque.

RESULTS

Adventitia V_p and adventitia K^trans were significantly correlated with plaque V_p and plaque K^trans at baseline. Rosuvastatin significantly reduced both adventitial and plaque V_p significantly at 3 months from 0.121 ± 0.064 to 0.085 ± 0.049 (P = .008) and from 0.096 ± 0.052 to 0.067 ± 0.043 (P = .013). Adventitial and plaque V_p continued to decrease by 43% and 34% at 12 months and by 49% and 45% at 24 months. However, the continued reductions from 3 to 12 months and from 12 to 24 months were not statistically significant. Adventitial and plaque K^trans showed similar trends, but nonstatistically significant decreases during the 24 months of treatment.

CONCLUSIONS

Rosuvastatin therapy rapidly and significantly decreased adventitial and plaque neovascularization at 3 months followed by continued, but nonstatistically significant, decreases at 12 and 24 months.

Statin Effects on Incidence, Treatment Success, and Mortality of Clostridium difficile Infections

PURPOSE

To review the effects of statin use in patients at risk for or diagnosed with Clostridium difficile infection (CDI) on CDI incidence, treatment success, and mortality.

METHODS

A literature search was performed through January 2019 using the following terms: statins, HMG-CoA inhibitors, Clostridium difficile, Clostridium difficile associated diarrhea, and Clostridium difficile infection. Additional references were identified from a review of literature citations. Studies evaluating statin effects on C difficile-related outcomes were included.

RESULTS

A total of 8 studies were identified for inclusion in this review. All studies were retrospective. Five studies reported the association between statin use and the development of CDI, suggesting that statins may decrease risk of CDI development in patients already on statin. In one study, there was an improved treatment response against CDI with the use of statin. Three retrospective studies evaluated statin use and mortality from CDI and only one study found significant mortality benefit in statin users.

CONCLUSIONS

Statin use may have a protective effect against the development of CDI and improve CDI treatment success; however, it is unclear if use confers a mortality benefit. Current data remain sparse and larger, prospective studies are needed to confirm current results and identify the specific population that may benefit the most from this intervention.

Nonhuman Primates and Translational Research-Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States. Human epidemiological studies provide challenges for understanding mechanisms that regulate initiation and progression of CVD due to variation in lifestyle, diet, and other environmental factors. Studies describing metabolic and physiologic aspects of CVD, and those investigating genetic and epigenetic mechanisms influencing CVD initiation and progression, have been conducted in multiple Old World nonhuman primate (NHP) species. Major advantages of NHPs as models for understanding CVD are their genetic, metabolic, and physiologic similarities with humans, and the ability to control diet, environment, and breeding. These NHP species are also genetically and phenotypically heterogeneous, providing opportunities to study gene by environment interactions that are not feasible in inbred animal models. Each Old World NHP species included in this review brings unique strengths as models to better understand human CVD. All develop CVD without genetic manipulation providing multiple models to discover genetic variants that influence CVD risk. In addition, as each of these NHP species age, their age-related comorbidities such as dyslipidemia and diabetes are accelerated proportionally 3 to 4 times faster than in humans.In this review, we discuss current CVD-related research in NHPs focusing on selected aspects of CVD for which nonprimate model organism studies have left gaps in our understanding of human disease. We include studies on current knowledge of genetics, epigenetics, calorie restriction, maternal calorie restriction and offspring health, maternal obesity and offspring health, nonalcoholic steatohepatitis and steatosis, Chagas disease, microbiome, stem cells, and prevention of CVD.

Study of Endothelio- and Osteoprotective Effects of Combination of Rosuvastatin with L-Norvaline in Experiment

The experiment was carried out on 120 female white Wistar rats, to study the endothelio- and osteoprotective action of the combination of rosuvastatin with L-norvaline in the model of experimental osteoporosis. It was found that, after ovariectomy in rats, endothelial dysfunction of the vessels of the microcirculatory bed of bone tissue develops, leading to the appearance of osteoporosis, but the combination of the studied drugs prevents the decrease in the level of microcirculation in the bone tissue, thereby preventing the thinning of bone trabeculae and preventing the occurrence of microfractures in them.

Diet-Modulated Lipoprotein Metabolism and Vascular Inflammation Evaluated by 18F-fluorodeoxyglucose Positron Emission Tomography

Vascular inflammation plays a central role in atherosclerosis, from initiation and progression to acute thrombotic complications. Modified low-density lipoproteins (LDLs) and apoB-containing particles stimulate plaque inflammation by interacting with macrophages. Loss of function of high-density lipoprotein (HDL) for preventing LDL particles from oxidative modification in dyslipidemic states may amplify modified LDL actions, accelerating plaque inflammation. Diets are one of the most important factors that can affect these processes of lipoprotein oxidation and vascular inflammation. Recently, ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has emerged as a reliable noninvasive imaging modality for identifying and quantifying vascular inflammation within atherosclerotic lesions based on the high glycolytic activity of macrophages infiltrating active atherosclerotic plaques. Vascular inflammation evaluated by FDG PET has been positively related to metabolic syndrome components and traditional risk factors of cardiovascular disease, including high-sensitivity C-reactive protein, body mass index, and insulin resistance. A positive association of vascular inflammation with endothelial dysfunction, resistin levels, pericardial adipose tissue, and visceral fat area has also been reported. In contrast, HDL cholesterol and adiponectin have been inversely related to vascular inflammation detected by FDG PET. Because of its reproducibility, serial FDG PET shows potential for tracking the effects of dietary interventions and other systemic and local antiatherosclerotic therapies for plaque inflammation.

Pravastatin polarizes the phenotype of macrophages toward M2 and elevates serum cholesterol levels in apolipoprotein E knockout mice

Objective

Statins are clinically used for protection against cardiovascular disease with lipid-lowering and anti-inflammatory properties. These properties tip the balance of macrophage polarization, which is an essential process in the development and progression of atherosclerosis. This study aimed to investigate the effect of pravastatin on atherosclerosis of the aorta in apolipoprotein E knockout (apoE-KO) mice without high lipid feeding.

Methods

Six 8-week-old apoE-KO male mice were randomly divided into two groups: a control group and a pravastatin (40 mg·kg⁻¹·day⁻¹)-treated group. At 35 weeks, the mice were sacrificed and the size of plaques on the aorta was assessed by Oil Red O staining. M1 and M2 macrophages were identified by inducible nitric oxide synthase and arginase-I, respectively, using immunohistochemistry.

Results

Pravastatin increased the size of atherosclerotic plaques in apoE-KO mice without high lipid feeding. The ratio of M1/M2 macrophages increased in atherosclerotic plaques, which might slow the process of atherosclerosis, while blood cholesterol levels were elevated.

Conclusion

Our study suggests that pravastatin polarizes the phenotype of macrophages toward M2 in atherosclerotic lesions, despite an increase in serum cholesterol levels in ApoE-KO mice.

Importance of the lipid-related pathways in the association between statins, mortality, and cardiovascular disease risk: The Multi-Ethnic Study of Atherosclerosis

PURPOSE

Estimating how much of the impact of statins on coronary heart diseases (CHD), cardiovascular disease (CVD), and mortality risk is attributable to their effect on low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and triglycerides.

METHODS

A semi-parametric g-formula estimator together with data from the Multi-Ethnic Study of Atherosclerosis (a prospective multi-center cohort study) was utilized to perform a mediation analysis. A total of 5280 participants, men and women of various race/ethnicities from multiple sites across the United States, were considered in the current study.

RESULTS

The adherence adjusted total relative risk reduction (RRR) estimate (95% confidence interval) of statins on CHD was 14% (-16%, 37%), and the indirect component through LDL was 23% (-4%, 58%). For CVD, the total RRR was 23% (2%, 40%), and the indirect component through LDL was 5% (-13%, 25%). The total RRR of mortality was 18% (-1%, 35%), and the indirect component through LDL was -4% (-17%, 12%). The estimated indirect components through HDL and triglycerides were close to zero with narrow confidence intervals for all 3 outcomes.

CONCLUSIONS

The estimated effect of statins on mortality, CVD, and CHD appeared to be independent of their estimated effect on HDL and triglycerides. Our study provides evidence that the preventive effect of statins on CHD could be attributed in large part to their effect on LDL. Our g-formula estimator is a promising approach to elucidate pathways, even if it is hard to make firm conclusions for the LDL pathway on mortality and CVD.

Pleiotropic Effects of Statins on the Cardiovascular System

The statins have been used for 30 years to prevent coronary artery disease and stroke. Their primary mechanism of action is the lowering of serum cholesterol through inhibiting hepatic cholesterol biosynthesis thereby upregulating the hepatic low-density lipoprotein (LDL) receptors and increasing the clearance of LDL-cholesterol. Statins may exert cardiovascular protective effects that are independent of LDL-cholesterol lowering called pleiotropic effects. Because statins inhibit the production of isoprenoid intermediates in the cholesterol biosynthetic pathway, the post-translational prenylation of small GTP-binding proteins such as Rho and Rac, and their downstream effectors such as Rho kinase and nicotinamide adenine dinucleotide phosphate oxidases are also inhibited. In cell culture and animal studies, these effects alter the expression of endothelial nitric oxide synthase, the stability of atherosclerotic plaques, the production of proinflammatory cytokines and reactive oxygen species, the reactivity of platelets, and the development of cardiac hypertrophy and fibrosis. The relative contributions of statin pleiotropy to clinical outcomes, however, remain a matter of debate and are hard to quantify because the degree of isoprenoid inhibition by statins correlates to some extent with the amount of LDL-cholesterol reduction. This review examines some of the currently proposed molecular mechanisms for statin pleiotropy and discusses whether they could have any clinical relevance in cardiovascular disease.

Association between serum alkaline phosphatase and coronary artery calcification in a sample of primary cardiovascular prevention patients

BACKGROUND AND AIMS

A high level of serum alkaline phosphatase (ALP) is associated with an increased risk of mortality and myocardial infarction. ALP hydrolyses inorganic pyrophosphate, which is a strong inhibitor of calcium phosphate deposition. The aim of this study was to determine whether ALP is associated with the coronary artery calcium score (CACS).

METHODS

We examined the association of CACS, assessed by computed tomography scanning, and ALP, in 500 patients consecutively recruited, free of cardiovascular disease. The CACS were categorized into two groups: no calcification (CACS = 0) (n = 187) and with calcification (CACS>0) (n = 313). ALP activity was divided into three tertile groups: low ALP level (<55 IU/L), intermediate (55-66 IU/L) and high ALP level (>66 IU/L).

RESULTS

The mean age was 60.9 ± 10.8 years, 49.6% of the patients were women. ALP ranged from 22 to 164 IU/L (mean 62.6 IU/L, SD 19.3). In univariate analysis, traditional cardiovascular risk factors, statin use (p = 0.001), and ALP (p = 0.001) were significantly associated with CACS. After adjusting for cardiovascular risk factors, only age (p = 0.001) and sex (p = 0.001) were independently associated with CACS. Compared to the tertile group with low levels of ALP, the intermediate tertile group [OR 2.11, 95% CI (1.12; 3.96), p = 0.02], as well as the high tertile group [OR 3.89, 95% CI (2.01; 7.54), p = 0.001)], was independently associated with CACS.

CONCLUSIONS

In patients free of cardiovascular disease, high ALP levels are positively and independently associated with coronary artery calcification. The metabolic pathway of ALP and inorganic pyrophosphate could be a target for new therapies against vascular calcification.

Perioperative Statin Therapy for Patients Undergoing Coronary Artery Bypass Grafting

Coronary artery bypass grafting is associated with an intense systemic inflammatory response, which is linked to postoperative complications. Beyond lipid lowering, statins exert a constellation of beneficial actions, including an antiinflammatory role, known as pleiotropic effects. There is increasing evidence that perioperative statin therapy improves outcomes in patients undergoing coronary artery bypass grafting. Statins are underused in the coronary artery bypass grafting population, because perioperative discontinuation remains a common practice. This article provides an extensive review of the available literature on the effect of perioperative statin therapy on post–coronary artery bypass grafting outcomes and weighs the evidence for the concerns about increased incidence of statin-related adverse effects in this setting.

Longer duration of statin therapy is associated with decreased carotid plaque vascularity by magnetic resonance imaging

OBJECTIVE

Plaque neovasculature is a major route for lipoprotein and leukocyte ingress into plaques, and has been identified as a risk factor for carotid plaque disruption. Vp, a variable derived from pharmacokinetic modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), correlates with plaque neovasculature density. Because lipid-lowering therapy has been associated with regression of neovasculature in animal models, we sought to determine clinical correlates of carotid plaque neovasculature (as assessed by Vp) in participants on statin therapy for established cardiovascular disease.

METHODS

98 participants from an AIM-HIGH sub-study underwent DCE-MRI of their carotid arteries. Expert readers who were blinded to all clinical variables analyzed the MR images to measure carotid plaque Vp in all participants. Associations between Vp and duration of statin therapy and other clinical risk factors were analyzed.

RESULTS

Prior duration of statin treatment at enrollment ranged from <1 year (21%) 1-5 years (40%) and >5 years (39%). In univariate analyses, shorter duration of statin therapy (P = 0.01), the presence of metabolic syndrome (P = 0.02), and higher body mass index (P = 0.01) and lipoprotein(a) (P = 0.01) were all significantly associated with higher baseline Vp values. In multivariate analyses, significant associations remained between shorter duration of statin therapy (P = 0.004) and lipoprotein(a) (P = 0.04).

CONCLUSIONS

These are the first human, in vivo findings suggesting a relationship between duration of statin therapy and regression of carotid plaque neovasculature. Future longitudinal studies are warranted both to confirm this finding and to address whether changes in neovasculature may translate into change in risk for plaque disruption. CLINICALTRIALS.

GOV IDENTIFIERS

NCT00880178, NCT01178320 and NCT00120289.

Biochemistry of Statins

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Elevated blood lipids may be a major risk factor for CVD. Due to consistent and robust association of higher low-density lipoprotein (LDL)-cholesterol levels with CVD across experimental and epidemiologic studies, therapeutic strategies to decrease risk have focused on LDL-cholesterol reduction as the primary goal. Current medication options for lipid-lowering therapy include statins, bile acid sequestrants, a cholesterol-absorption inhibitor, fibrates, nicotinic acid, and omega-3 fatty acids, which all have various mechanisms of action and pharmacokinetic properties. The most widely prescribed lipid-lowering agents are the HMG-CoA reductase inhibitors, or statins. Since their introduction in the 1980s, statins have emerged as the one of the best-selling medication classes to date, with numerous trials demonstrating powerful efficacy in preventing cardiovascular outcomes (Kapur and Musunuru, 2008 [1]). The statins are commonly used in the treatment of hypercholesterolemia and mixed hyperlipidemia. This chapter focuses on the biochemistry of statins including their structures, pharmacokinetics, and mechanism of actions as well as the potential adverse reactions linked to their clinical uses.

Simvastatin Attenuates Oxidative Stress, NF-κB Activation, and Artery Calcification in LDLR-/- Mice Fed with High Fat Diet via Down-regulation of Tumor Necrosis Factor-α and TNF Receptor 1

Simvastatin (SIM) is anti-inflammatory. We used low density lipoprotein receptor knockout (LDLR-/-) mice and human aortic smooth muscle cells (HASMCs) as model systems to study the effect of SIM on arterial calcification and to explore the potential mechanisms contributing to this protective effect. High-fat diet (HFD) caused the LRLR -/- to develop dyslipidemia, diabetics, atherosclerosis and aortic smooth muscle calcification. SIM, N-acetyl cysteine (NAC, a ROS scavenger) and apocynin (APO, a NADPH oxidase inhibitor) did not significantly retard the development of dyslipidemia or diabetic. However, those treatments were still effective in attenuating the HFD-induced atherosclerosis and aortic smooth muscle calcification. These findings suggest that the protective effect of SIM against aortic calcification is not contributed by the cholesterol lowering effect. SIM, NAC and APO were found to attenuate the HFD induced elevation of serum TNF-α, soluble TNFR1 (sTNFR1), 3-nitro-tyrosine. We hypothesized that the pro-inflammatory cytokine, oxidative stress and TNFR1 played a role in inducing aortic calcification. We used HASMC to investigate the role of TNF-α, oxidative stress and TNFR1 in inducing aortic calcification and to elucidate the mechanism contributes the protective effect of SIM against aortic calcification. We demonstrated that treating HASMC with TNF-α induced cell Ca deposit and result in an increase in ALP, NADPH oxidase activity, NF-kB subunit p65, BMP2, MSX2, and RUNX2 expression. SIM suppressed the TNF-α induced activation of NADPH oxidase subunit p47, the above-mentioned bone markers and TNFR1 expression. Furthermore, p65, p47 and TNFR1 siRNAs inhibited the TNF-α-mediated stimulation of BMP-2, MSX2, RUNX2 expression. SIM, APO, and NAC either partially inhibit or completely block the TNF-α induced H2O2 or superoxide production. These results suggest that SIM may, independent of its cholesterol-lowering effect, suppresses the progression of vascular diseases through the inhibition of the inflammation mediators TNF-α and TNFR1.

Beneficial effects of soy supplementation on postmenopausal atherosclerosis are dependent on pretreatment stage of plaque progression

OBJECTIVE

The objective of this study was to use a well-established monkey model of atherosclerosis to determine how life stage and preexisting atherosclerosis influence the effectiveness of high-isoflavone soy diet in inhibiting progression of atherosclerosis.

METHODS

For 34 months, premenopausal monkeys were fed an atherogenic diet, with protein derived primarily from either animal sources (casein-lactalbumin [CL], n = 37) or high-isoflavone soy beans (Soy, n = 34). Animals were ovariectomized and randomized to groups fed the same diet (CL-CL, n = 20; Soy-Soy, n = 17) or an alternate diet (CL-Soy, n = 17; Soy-CL, n = 17) for an additional 34 months. At ovariectomy, the left common iliac artery was removed to determine the amount of premenopausal atherosclerosis. At necropsy, the right common iliac artery and coronary arteries were collected, and atherosclerosis extent was quantified. CL-CL condition was considered "control."

RESULTS

Modeling Asian women who remain in Asia, monkeys fed soy protein both premenopausally and postmenopausally had a markedly reduced extent of coronary artery atherosclerosis relative to CL controls (P = 0.008). The subset of animals that modeled Asian women who migrate to a Western country (consuming soy premenopausally and CL postmenopausally) had increased progression of postmenopausal iliac artery atherosclerosis (P = 0.003) and was not protected against the development of coronary artery atherosclerosis relative to controls. Relevant to the administration of soy diets to postmenopausal Western women, monkeys fed CL premenopausally and switched to soy postmenopausally derived atheroprotective benefits only if they began the postmenopausal treatment period with relatively small (below the median) plaques. Relative to controls, this group (with small plaques at ovariectomy) had reduced progression of iliac atherosclerosis (P = 0.038) and smaller coronary artery plaques (P = 0.0001) that were less complicated (P = 0.05) relative to controls.

CONCLUSIONS

The results suggest that significant atheroprotective benefits of dietary soy are derived from treatment that begins premenopausally and continues postmenopausally or from treatment that is started during early postmenopause (when plaques are still small).

Effect of High-Dose Statin Therapy on Drug-Eluting Stent Strut Coverage

Objective—

The influence of high-dose statin therapy on the serial stent healing process has not been fully investigated. Using optical coherence tomography, the effect of high-dose statin therapy on stent strut coverage was evaluated in drug-eluting stent–treated patients.

Approach and Results—

Sixty patients were randomly assigned to 2 groups according to the statin dose (atorvastatin 40 mg as high-dose statin therapy [n=29] versus pravastatin 20 mg as low-dose statin therapy [n=31]). Serial optical coherence tomographic evaluation post procedure and at the 3-month and 12-month follow-ups was performed in 50 patients with 54 stents (23 atorvastatin-treated patients versus 27 pravastatin-treated patients). The percentage of uncovered struts was defined as the ratio of uncovered struts/total struts. The primary end point was the percentage of uncovered struts at the 12-month follow-up. The secondary end point was the percentage of uncovered struts at the 3-month follow-up and the comparative percentage change (Δ) of uncovered struts at the 3- and 12-month follow-ups between the different dose statin therapies. The percentage of uncovered struts was 7.4% (range, 4.3%–10.4%) in atorvastatin-treated patients versus 10.6% (range, 5.7%–22.6%) in pravastatin-treated patients at the 3-month follow-up ( P =0.13) and 1.3% (0.3%–3.8%) versus 2.5% (0.9%–9.7%), respectively, at the 12-month follow-up ( P =0.01). The percentage Δ of uncovered struts from 3 to 12 months of follow-up was −7.9±8.5% in atorvastatin-treated patients versus −9.3±12.5% in pravastatin-treated patients ( P =0.67).

Conclusions—

This study suggested that high-dose statin therapy might provide a beneficial effect for the vascular healing process after drug-eluting stent implantation.

An In Vitro Cynomolgus Vascular Surrogate System for Preclinical Drug Assessment and Human Translation

Objectives—

The predictive value of animal and in vitro systems for drug development is limited, particularly for nonhuman primate studies as it is difficult to deduce the drug mechanism of action. We describe the development of an in vitro cynomolgus macaque vascular system that reflects the in vivo biology of healthy, atheroprone, or advanced inflammatory cardiovascular disease conditions.

Approach and Results—

We compare the responses of the in vitro human and cynomolgus vascular systems to 4 statins. Although statins exert beneficial pleiotropic effects on the human vasculature, the mechanism of action is difficult to investigate at the tissue level. Using RNA sequencing, we quantified the response to statins and report that most statins significantly increased the expression of genes that promote vascular health while suppressing inflammatory cytokine gene expression. Applying computational pathway analytics, we identified statin-regulated biological themes, independent of cholesterol lowering, that provide mechanisms for off-target effects, including thrombosis, cell cycle regulation, glycogen metabolism, and ethanol degradation.

Conclusions—

The cynomolgus vascular system described herein mimics the baseline and inflammatory regional biology of the human vasculature, including statin responsiveness, and provides mechanistic insight not achievable in vivo.

Statins meditate anti-atherosclerotic action in smooth muscle cells by peroxisome proliferator-activated receptor-γ activation

The peroxisome proliferator-activated receptor-γ (PPARγ) is an important regulator of lipid and glucose metabolism, and its activation is reported to suppress the progression of atherosclerosis. We have reported that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) activate PPARγ in macrophages. However, it is not yet known whether statins activate PPARγ in other vascular cells. In the present study, we investigated whether statins activate PPARγ in smooth muscle cells (SMCs) and endothelial cells (ECs) and thus mediate anti-atherosclerotic effects. Human aortic SMCs (HASMCs) and human umbilical vein ECs (HUVECs) were used in this study. Fluvastatin and pitavastatin activated PPARγ in HASMCs, but not in HUVECs. Statins induced cyclooxygenase-2 (COX-2) expression in HASMCs, but not in HUVECs. Moreover, treatment with COX-2-siRNA abrogated statin-mediated PPARγ activation in HASMCs. Statins suppressed migration and proliferation of HASMCs, and inhibited lipopolysaccharide-induced expression of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) in HASMCs. These effects of statins were abrogated by treatment with PPARγ-siRNA. Treatment with statins suppressed atherosclerotic lesion formation in Apoe(-/-) mice. In addition, transcriptional activity of PPARγ and CD36 expression were increased, and the expression of MCP-1 and TNF-α was decreased, in the aorta of statin-treated Apoe(-/-) mice. In conclusion, statins mediate anti-atherogenic effects through PPARγ activation in SMCs. These effects of statins on SMCs may be beneficial for the prevention of atherosclerosis.

Early decrease in carotid plaque lipid content as assessed by magnetic resonance imaging during treatment of rosuvastatin

Background

Statin therapy has shown to deplete atherosclerotic plaque lipid content and induce plaque regression. However, how early the plaque lipid depletion can occur with low-density lipoprotein cholesterol (LDL-C) lowering in humans in vivo has not been fully described.

Methods

We enrolled 43 lipid treatment naïve subjects with asymptomatic carotid atherosclerosis and LDL-C ≥ 100 and ≤ 250 mg/dl. Rosuvastatin 5–20 mg/day was used to lower LDL-C levels to < 80 mg/dl. Lipid profile and carotid MRI scans were obtained at baseline, 3, 12, and 24 months. Carotid plaque lipid-rich necrotic core (LRNC) and plaque burden were measured and compared between baseline and during treatment.

Results

Among the 32 subjects who completed the study, at 3 months, an average dose of rosuvastatin of 11 mg/day lowered LDL-C levels by 47% (125.2 ± 24.4 mg/dl vs. 66.7 ± 17.3 mg/dl, p < 0.001). There were no statistically significant changes in total wall volume, percent wall volume or lumen volume. However, LRNC volume was significantly decreased by 7.9 mm³, a reduction of 7.3% (111.5 ± 104.2 mm³ vs. 103.6 ± 95.8 mm³, p = 0.044). Similarly, % LRNC was also significantly decreased from 18.9 ± 11.9% to 17.9 ± 11.5% (p = 0.02) at 3 months. Both LRNC volume and % LRNC continued to decrease moderately at 12 and 24 months, although this trend was not significant.

Conclusions

Among a small number of lipid treatment naïve subjects, rosuvastatin therapy may induce a rapid and lasting decrease in carotid plaque lipid content as assessed by MRI.

Trial registration

ClinicalTrials.Gov numbers NCT00885872

Low-density lipoprotein-cholesterol-induced endothelial dysfunction and oxidative stress: the role of statins

SIGNIFICANCE

Cardiovascular diseases (CVD) represent a major public health burden. High low-density lipoprotein (LDL)-cholesterol is a recognized pathogenic factor for atherosclerosis, and its complications and statins represent the most potent and widely used therapeutic approach to prevent and control these disorders.

RECENT ADVANCES

A number of clinical and experimental studies concur to identify endothelial dysfunction as a primary step in the development of atherosclerosis, as well as a risk factor for subsequent clinical events. Oxidant stress resulting from chronic elevation of plasma LDL-cholesterol (LDL-chol) is a major contributor to both endothelial dysfunction and its complications, for example, through alterations of endothelial nitric oxide signaling.

CRITICAL ISSUES

Statin treatment reduces morbidity and mortality of CVD, but increasing evidence questions that this is exclusively through reduction of plasma LDL-chol. The identification of ancillary effects on (cardio)vascular biology, for example, through their modulation of oxidative stress, will not only increase our understanding of their mechanisms of action, with a potential broadening of their indication(s), but also lead to the identification of new molecular targets for future therapeutic developments in CVD.

FUTURE DIRECTIONS

Further characterization of molecular pathways targeted by statins, for example, not directly mediated by changes in plasma lipid concentrations, should enable a more comprehensive approach to the pathogenesis of (cardio)vascular disease, including, for example, epigenetic regulation and fine tuning of cell metabolism.

Contribution of the WHHL rabbit, an animal model of familial hypercholesterolemia, to elucidation of the anti-atherosclerotic effects of statins

This year marks the 40th year since the discovery of a mutant rabbit showing spontaneous hyperlipidemia, which is the proband of the Watanabe heritable hyperlipidemic (WHHL) rabbit strain, an animal model of familial hypercholesterolemia, and the first statin, a general term for inhibitors of 3-hydroxy-3-methylglutaryl CoA reductase, a rate limiting enzyme in cholesterol biosynthesis. Nowadays, statins are the primary drug of choice for treating cardiovascular disease. Although several reviews have described clinical trials and in vitro studies of statins, the anti-atherosclerotic effects of statins on animal models have not been comprehensively reviewed. This review summarized the contribution of WHHL rabbits to elucidating the anti-atherosclerotic effects of statins in vivo. Studies using WHHL rabbits verified that statins suppress plaque destabilization by reducing unstable components (foam cells derived from macrophages, foam cell debris, and extracellular lipid accumulation), preventing smooth muscle cell reductions, and increasing the collagen content of plaques. In addition, the expression of matrix metalloproteinases and tissue factor are decreased in intimal macrophages by statin treatment. Lipid-lowering effects of statins alter plaque biology by reducing the proliferation and activation of macrophages, a prominent source of the molecules responsible for plaque instability and thrombogenicity. Although statins remain the standard treatment for cardiovascular disease, new therapeutics are eagerly awaited. WHHL rabbits will continue to contribute to the development of therapeutics.

Statins in heart failure: do we need another trial?

Statins lower serum cholesterol and are employed for primary and secondary prevention of cardiovascular events. Clinical evidence from observational studies, retrospective data, and post hoc analyses of data from large statin trials in various cardiovascular conditions, as well as small scale randomized trials, suggest survival and other outcome benefits for heart failure. Two recent large randomized controlled trials, however, appear to suggest statins do not have beneficial effects in heart failure. In addition to lowering cholesterol, statins are believed to have many pleotropic effects which could possibly influence the pathophysiology of heart failure. Following the two large trials, evidence from recent studies appears to support the use of statins in heart failure. This review discusses the role of statins in the pathophysiology of heart failure, current evidence for statin use in heart failure, and suggests directions for future research.

Effect of statin therapy on the progression of coronary atherosclerosis

BACKGROUND

An increasing number of authors employing intravascular ultrasound (IVUS) and virtual histology (VH-IVUS) have investigated the effect of statin use on plaque volume (PV) and plaque composition. However, inconsistent results have been reported. Therefore, we conducted a meta-analysis to determine the appropriate regimen of statins to effectively stabilize vulnerable coronary plaques.

METHODS

Online electronic databases were carefully searched for all relevant studies. We compared mean values of PV and plaque composition between baseline and follow-up in patients receiving statin therapy. We pooled treatment effects and calculated mean differences (MD) with the 95% confidence interval (CI) using a random-effects model. By stratified analyses, we explored the influence of clinical presentation, dose and duration of statin treatment, and low-density lipoprotein-cholesterol (LDL-C) levels on the effects of statins.

RESULTS

Seventeen studies involving 2,171 patients were analyzed. Statin therapy significantly decreased PV (-5.3 mm(3); 95% CI: -3.3 mm(3) to -7.2 mm(3) P < 0.001), without heterogeneity. When considering the dose and duration of statins used, only subgroups employing a high dose and long duration demonstrated a significant reduction in PV (p < 0.001). A significant decrease in PV was noted if achieved LDL-C levels were <100 mg/dL (p < 0.001). Statin treatment could induce a twofold decrease in PV in patients with acute coronary syndrome (ACS) compared with that observed in patients with stable angina pectoris (SAP). A regressive trend was seen for necrotic core volume (MD: -2.1 mm(3); 95% CI: -4.7 mm(3) to 0.5 mm(3), P = 0.11). However, statin use did not induce a significant change for fibrotic, fibro-fatty, or dense calcium compositions.

CONCLUSIONS

Our meta-analysis demonstrated that statin therapy (especially that involving a high dose and long duration and achieving <100 mg/dL LDL-C levels) can significantly decrease PV in patients with SAP or ACS. These data suggested that statins can be used to reduce the atheroma burden for secondary prevention by appropriately selecting the statin regimen. No significant change in plaque composition was seen after statin therapy.

Statins improve outcome in murine models of intracranial hemorrhage and traumatic brain injury: a translational approach

Traumatic brain injury (TBI) and intracerebral hemorrhage (ICH) are leading causes of neurological mortality and disability in the U.S. However, therapeutic options are limited and clinical management remains largely supportive. HMG-CoA reductase inhibitors (statins) have pleiotropic mechanisms of action in the setting of acute brain injury, and have been demonstrated to improve outcomes in preclinical models of ICH and TBI. To facilitate translation to clinical practice, we now characterize the optimal statin and dosing paradigm in murine models of ICH and TBI. In a preclinical model of TBI, mice received vehicle, simvastatin, and rosuvastatin at doses of 1 mg/kg and 5 mg/kg for 5 days after the impact. Immunohistochemistry, differential gene expression, and functional outcomes (rotarod and Morris water maze testing) were assessed to gauge treatment response. Following TBI, administration of rosuvastatin 1 mg/kg was associated with the greatest improvement in functional outcomes. Rosuvastatin treatment was associated with histological evidence of reduced neuronal degeneration at 24 h post-TBI, reduced microgliosis at day 7 post-TBI, and preserved neuronal density in the CA3 region at 35 days post-injury. Administration of rosuvastatin following TBI was also associated with downregulation of inflammatory gene expression in the brain. Following ICH, treatment with simvastatin 1 mg/kg was associated with the greatest improvement in functional outcomes, an effect that was independent of hemorrhage volume. Clinically relevant models of acute brain injury may be used to define variables such as optimal statin and dosing paradigms to facilitate the rational design of pilot clinical trials.

Digital tomosynthesis for aortic arch calcification evaluation: performance comparison with chest radiography with CT as the reference standard

BACKGROUND

Recently developed digital tomosynthesis has shown improved detection of pulmonary lesions with a radiation dose comparable to conventional CR but with a much lower radiation dose than CT.

PURPOSE

To compare the diagnostic performance of digital tomosynthesis (DT) with that of chest radiography (CR) for the detection of aortic arch calcification (AAC).

MATERIAL AND METHODS

The study included 100 patients who underwent multidetector computed tomography (MDCT), DT, and CR (DT and CR were obtained within one week of CT examination). We evaluated and compared the diagnostic performances of DT and CR for the detection of AAC with MDCT as the reference standard. The extent (four grades 0-3) of AAC on DT and CR was also compared with CT calcium score. Inter-observer agreement was analyzed by using kappa statistics.

RESULTS

On DT, overall accuracy for AAC was superior to that of CR (94% and 71%, respectively, P < 0.01). Inter-observer agreement was good with DT and CR (kappa values = 0.74 and 0.62, respectively) for the presence of AAC, and good with DT and moderate with CR (kappa value = 0.64 and 0.53, respectively) for AAC grading. The overall correlation coefficient on AAC grading between DT and CT (calcium score) was superior to that between CR and CT (0.90 and 0.60, respectively).

CONCLUSION

DT is superior to CR for detection and extent evaluation of AAC.

Role of endothelial nitric oxide in cerebrovascular regulation

Endothelial nitric oxide (NO) plays important roles in the vascular system. Animal models that show vascular dysfunction demonstrate the protective role of endothelial NO dependent pathways. This review focuses on the role of endothelial NO in the regulation of cerebral blood flow and vascular tone. We will discuss the importance of NO in cerebrovascular function using animal models with altered endothelial NO production under normal, ischemic and reperfusion conditions, as well as in hyperoxia. Pharmacological and genetic manipulations of the endothelial NO system demonstrate the essential roles of endothelial NO synthase in maintenance of vascular tone and cerebral perfusion under normal and pathological conditions.

Bicuspid aortic valve disease: the role of oxidative stress in Lrp5 bone formation

The bicuspid aortic valve is a common congenital cardiac anomaly, having a prevalence of 0.9% to 1.37% in the general population and a male preponderance ratio of 2:1. The recognition of a bicuspid aortic valve is clinically relevant because of its association with aortic stenosis or regurgitation, aortic aneurysm or dissection, and infective endocarditis. Although some patients with a bicuspid aortic valve may go undetected without clinical complications for a lifetime, the vast majority will require intervention, most often surgery, at some point. In fact, the natural history of bicuspid aortic valve is that of valve calcification and progressive stenosis that typically occur at a faster rate than in tricuspid aortic valves. This pattern of presentation supports the hypothesis that shear stress in patients with congenitally abnormal aortic valves may contribute to an earlier leaflet calcification. However, there is emerging research data showing that the valve calcification process might have a similar pathophysiologic process to that of vascular atherosclerosis. This review focuses on the current knowledge of the cellular mechanisms of bicuspid aortic valve.

Assessment of IgG antibodies to oxidized LDL in patients with acute coronary syndrome

OBJECTIVES

Circulating IgG antibodies to oxidized low-density lipoprotein (anti-oxLDL) have been implicated in the development of atherosclerotic plaques. In this study, we investigated the prognostic value of IgG anti-oxLDL antibodies in patients with acute coronary syndrome (ACS).

METHODS

In total 54 patients with ACS and 41 matched healthy controls were involved in this prospective study. Serum IgG anti-oxLDL levels were assessed by ELISA.

RESULTS

Higher IgG anti-oxLDL levels were found in patients with ACS versus controls (22.8 ± 23.3 vs. 7.5 ± 5.27 EU/ml, p < 0.0001). IgG anti-oxLDL concentrations were significantly higher in ACS patients with unstable clinical complications (circulatory insufficiency, malignant arrhythmias, recurring ischaemic pain, positive stress-test, need for urgent coronary intervention or sudden cardiac death) versus those without such complications (30.0 vs. 11.7 EU/ml, p < 0.001). Twelve patients (22%) were taking statins. Patients on statins had a significant reduction in clinical complications (33%) versus patients not receiving statin therapy (61%). IgG anti-oxLDL levels were also different in these two groups (11.4 vs. 25.8 EU/ml, respectively; p = 0.03). Serum IgG anti-oxLDL levels correlated with the subsequent development of unstable coronary events. Levels of anti-oxLDL significantly decreased in response to statin therapy, independently of its lipid-lowering effect.

CONCLUSIONS

Anti-oxLDL antibodies are involved in ACS. The association of anti-oxLDL with unstable clinical complications may indicate the role of this antibody in plaque destabilization.

Carotid artery atherosclerosis: effect of intensive lipid therapy on the vasa vasorum--evaluation by using dynamic contrast-enhanced MR imaging

PURPOSE

To investigate whether short-term, intensive lipid therapy leads to changes in microvascular characteristics, as measured by using dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained for this HIPAA-compatible study. Subjects with established coronary artery disease or carotid artery stenosis of 15% or greater determined by using ultrasonography and with levels of apolipoprotein B of 120 mg/dL (1.2 g/L) or greater were enrolled in an ongoing study (clinical trial NCT00715273). All received intensive lipid therapy to achieve targeted high- and low-density lipoprotein cholesterol levels and underwent serial serum monitoring including high-sensitivity C-reactive protein (HsCRP) level measurements. Carotid artery MR imaging examinations including morphologic and DCE MR images were obtained at baseline and 1 year after treatment. In subjects with advanced lesions (>2 mm thick), MR image analysis was performed, including measurement of lipid-rich necrotic core size and kinetic modeling of DCE MR images to assess changes in the transfer constant (K(trans)). The differences in K(trans) between baseline and 1-year follow-up were compared by using the Wilcoxon signed rank test, and associations were assessed by using the Spearman rank correlation coefficient.

RESULTS

Twenty-eight subjects with interpretable DCE MR imaging results at both baseline and 1-year follow-up were included. After 1 year of treatment, a significant reduction was found in mean K(trans) (0.085 min(-1) ± 0.037 [standard deviation] to 0.067 min(-1) ± 0.028, P = .02). Reduction in K(trans) was not significantly correlated with observed reductions in lipid-rich necrotic core size or reductions in HsCRP level.

CONCLUSION

These findings suggest that DCE MR imaging may be a useful imaging method for the assessment of the therapeutic response of the vasa vasorum in patients with atherosclerotic plaque.

Intravenous administration of pravastatin immediately after middle cerebral artery occlusion reduces cerebral oedema in spontaneously hypertensive rats

3-hydroxy-3-methyl-glutaryl-coenzyme-A (HMG-CoA) reductase inhibitors (statins) have been shown to protect against ischemic stroke by mechanisms that are independent of lowering serum cholesterol levels. In this study we investigated the potential neuroprotective effect of a single i.v. treatment with four increasing doses of pravastatin on permanent occlusion of middle cerebral artery (MCAo) in spontaneously hypertensive rats. Pravastatin was given 10 min after MCAo and its effect was determined 24 h later. Treatment results were evaluated in terms of infarct volume, homolateral hemisphere oedema, glial fibrillary acid (GFAP), vimentin (Vim) and endothelial NO synthase (eNOS) immunoreactivity and TUNEL positivity. Cerebral levels of eNOS were measured by western blot analysis. Pravastatin did not reduce cerebral infarct while it mitigated homolateral hemisphere oedema in a dose-dependent manner with respect to controls. No differences among groups were found regarding GFAP and Vim immunoreactivity and TUNEL positivity. Instead, pravastatin-treated animals presented a more marked cerebral eNOS immunoreactivity as compared with controls. In agreement with immunohistochemistry, immunoblot revealed dose-dependent increases in cerebral levels of eNOS in pravastatin rats. Our data confirm statin neuroprotection in cerebral ischemia. In particular, it is of great interest that a single i.v. Pravastatin administration reduced cerebral oedema by upregulating eNOS expression/activity. This, by increasing vascular NO bioavailability, could have produced proximal vasodilation and contributed to reducing perfusional deficit. It is worthy stressing how important the anti-oedema action is that pravastatin seems to exert. Indeed, cerebral oedema, when widespread and beyond limits of physiological compensation, causes endocranic hypertension and additional cerebral damage over time.

Pleiotropic effects of statins in atherosclerotic disease

Statins have an established role in the treatment of hypercholesterolemia and the prophylactic treatment of patients with atherosclerotic disease, and have been found to prevent secondary cardiovascular events and thereby reduce morbidity and mortality. Nevertheless, the pathophysiologic effect of statins on inflammatory responses and local atherosclerotic plaque morphology in humans remains a matter of debate. In particular the question is unanswered whether statin-induced alterations in plaque composition can be ascribed to LDL lowering or an anti-inflammatory pleiotropic effect. We will discuss the results of a recent study by Puato et al. concerning the effect of two different atorvastatin dosages and a nonstatin lipid-lowering drug on atherosclerotic plaque morphology.

Statins in traumatic brain injury

Traumatic brain injury (TBI) is a common cause of long-term neurological morbidity, with devastating personal and societal consequences. At present, no pharmacological intervention clearly improves outcomes, and therefore a compelling unmet clinical need remains. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or "statins," offer a potential novel therapeutic strategy for TBI. Statins are well tolerated, easy to administer, and have a long clinical track record in critically ill patients. Their side effects are well defined and easily monitored. Preclinical studies have shown significant benefit of statins in models of TBI and related disease processes, including cerebral ischemia, intracerebral hemorrhage, and subarachnoid hemorrhage. In fact, multiple mechanisms have been defined by which statins may exert benefit after acute brain injury. Statins are currently positioned to be translated into clinical trials in acute brain injury and have the potential to improve outcomes after TBI.

Statins have beneficial effects on platelet free radical activity and intracellular distribution of GTPases in hyperlipidaemia

In addition to lowering cholesterol, statins may alter endothelial release of the vasodilator NO and harmful superoxide free radicals. Statins also reduce cholesterol intermediates including isoprenoids. These are important for post-translational modification of substances including the GTPases Rho and Rac. By altering the membrane association of these molecules, statins affect intracellular positioning and hence activity of a multitude of substances. These include eNOS (endothelial NO synthase), which produces NO (inhibited by Rho), and NADPH oxidase, which produces superoxide (dependent on Rac). Statins may improve endothelial function by enhancing production of NO while decreasing superoxide production. A total of 40 hypercholesterolaemic patients were randomized to treatment with either atorvastatin or placebo; 20 normolipidaemic patients were also studied. Platelet nitrite, NO and superoxide were examined as was the cellular distribution of the GTPases Rho and Rac at baseline and after 8 weeks of treatment. Following atorvastatin therapy, platelet NO was increased (3.2 pmol/108 platelets) and superoxide output was attenuated [−3.4 pmol·min−1·(108 platelets)−1] when compared with placebo. The detection of both Rho and Rac was significantly reduced in the membranes of platelets, implying reduced activity. In conclusion, the results of the present study show altered NO/superoxide production following statin therapy. A potential mechanism for this is the change in the distribution of intracellular GTPases, which was considered to be secondary to decreases in isoprenoid intermediates, suggesting that the activity of the former had been affected by atorvastatin.

Statins inhibit cyclooxygenase-2 and matrix metalloproteinase-9 in human endothelial cells: anti-angiogenic actions possibly contributing to plaque stability

AIMS

Cyclooxygenase (COX)-2 expression is increased in inflammation and angiogenesis and also in atherosclerotic plaques, where it co-localizes with metalloproteinases (MMPs) involved in the fibrous cap weakening. Insight into the regulation of COX-2 and MMP-9 expression suggests the involvement of a Rho-dependent pathway. Because statins interfere with Rho activation, we investigated the statin effect on COX-2 and MMP expressions in the human endothelium.

METHODS AND RESULTS

Simvastatin and atorvastatin were incubated with endothelial cells for 12 h before stimulation with phorbol myristate acetate or tumour necrosis factor-alpha, for times suitable to assess the endothelial tube differentiation on Matrigel and COX-2 and MMPs activities, proteins, and mRNA expressions. At 0.1-10 micromol/L, both statins reduced COX-2 expression and activity, without affecting COX-1. The statin effect was reversed by mevalonate and geranylgeranyl-pyrophosphate and mimicked by the Rho inhibitor C3 transferase, indicating the involvement of Rho in the signal transduction pathway leading to COX-2 expression. In parallel, statins, as well as COX-2 inhibitors, reduced the MMP-9 stimulated release and the endothelial tubular differentiation.

CONCLUSION

In the human vascular endothelium, statins reduce COX-2 and MMP-9 expression and activity. Through this mechanism, statins exert an anti-angiogenic effect possibly contributing to the cholesterol-lowering-unrelated protective effects of statins against plaque inflammatory angiogenesis and rupture.