Aliskiren inhibits atherosclerosis development and improves plaque stability in APOE*3Leiden.CETP transgenic mice with or without treatment with atorvastatin

Efficacy of a novel PCSK9 inhibitory peptide alone and with evinacumab in a mouse model of atherosclerosis

Atherosclerosis is the major cause of cardiovascular disease. This study evaluated the effect of lipid lowering using a novel peptide inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9) and a monoclonal antibody against angiopoietin-like 3 (evinacumab), either alone or in combination in APOE∗3-Leiden.CETP mice fed a Western diet. Effects on body weight, plasma lipids, atherosclerotic lesion size, severity, composition, and morphology were assessed. Treatment with PCSK9 inhibitory peptide significantly decreased both cholesterol and triglycerides (-69% and -68%, respectively). Similar reductions were seen in evinacumab-treated mice (-44% and -55%, respectively). The combination of evinacumab and PCSK9 inhibitory peptide lowered these levels to a larger extent than evinacumab alone (cholesterol: -74%; triglycerides: -81%). Reductions occurred in non-HDL-C without changes in HDL-C. Atherosclerotic lesion size was significantly reduced in all treatment groups compared to vehicle controls (evinacumab: -72%; PCSK9 inhibitory peptide: -97%; combination: -98%). Similarly, all interventions improved atherosclerotic lesion severity, with more undiseased segments and fewer severe lesions. Evaluation of the composition of severe atherosclerotic plaques revealed significant improvement in lesion stability in mice treated with both evinacumab and PCSK9 inhibitory peptide, attributable to decreased macrophage content and increased collagen content. Additionally, evaluation of lipid concentrations in cynomolgus monkeys revealed the beneficial effects of the PCSK9 inhibitory peptide on total cholesterol and LDL-C levels. Treatment with a novel PCSK9 inhibitory peptide alone or with evinacumab shows great potential to reduce and stabilize atherosclerotic lesions.

Effects of repeated weight cycling on non-alcoholic steatohepatitis in diet-induced obese mice

Lifestyle interventions remain the treatment of choice for patients with obesity and metabolic complications, yet are difficult to maintain and often lead to cycles of weight loss and regain (weight cycling). Literature on weight cycling remains controversial and we therefore investigated the association between weight cycling and metabolic complications using preexistent obese mice. Ldlr-/-.Leiden mice received a high-fat diet (HFD) for 20 weeks to induce obesity. Subsequently, weight-cycled mice were switched between the healthy chow diet and HFD for four 2-week periods and compared to mice that received HFD for the total study period. Repeated weight cycling tended to decrease body weight and significantly reduced fat mass, whereas adipose tissue inflammation was similar relative to HFD controls. Weight cycling did not significantly affect blood glucose or plasma insulin levels yet significantly reduced plasma free fatty acid and alanine transaminase/aspartate transaminase levels. Hepatic macrovesicular steatosis was similar and microvesicular steatosis tended to be increased upon weight cycling. Weight cycling resulted in a robust decrease in hepatic inflammation compared to HFD controls while hepatic fibrosis and atherosclerosis development were not affected. These results argue against the postulate that repeated weight cycling leads to unfavorable metabolic effects, when compared to a continuous unhealthy lifestyle, and in fact revealed beneficial effects on hepatic inflammation, an important hallmark of non-alcoholic steatohepatitis.

Semaglutide Has Beneficial Effects on Non-Alcoholic Steatohepatitis in Ldlr-/-.Leiden Mice

Semaglutide, a glucagon-like peptide-1 receptor agonist, is an antidiabetic medication that has recently been approved for the treatment of obesity as well. Semaglutide is postulated to be a promising candidate for the treatment of non-alcoholic steatohepatitis (NASH). Here, Ldlr-/-.Leiden mice received a fast-food diet (FFD) for 25 weeks, followed by another 12 weeks on FFD with daily subcutaneous injections of semaglutide or vehicle (control). Plasma parameters were evaluated, livers and hearts were examined, and hepatic transcriptome analysis was performed. In the liver, semaglutide significantly reduced macrovesicular steatosis (-74%, p < 0.001) and inflammation (-73%, p < 0.001) and completely abolished microvesicular steatosis (-100%, p < 0.001). Histological and biochemical assessment of hepatic fibrosis showed no significant effects of semaglutide. However, digital pathology revealed significant improvements in the degree of collagen fiber reticulation (-12%, p < 0.001). Semaglutide did not affect atherosclerosis relative to controls. Additionally, we compared the transcriptome profile of FFD-fed Ldlr-/-.Leiden mice with a human gene set that differentiates human NASH patients with severe fibrosis from those with mild fibrosis. In FFD-fed Ldlr-/-.Leiden control mice, this gene set was upregulated as well, while semaglutide predominantly reversed this gene expression. Using a translational model with advanced NASH, we demonstrated that semaglutide is a promising candidate with particular potential for the treatment of hepatic steatosis and inflammation, while for the reversal of advanced fibrosis, combinations with other NASH agents may be necessary.

Atorvastatin Attenuates Diet-Induced Non-Alcoholic Steatohepatitis in APOE*3-Leiden Mice by Reducing Hepatic Inflammation

Patients with metabolic syndrome are often prescribed statins to prevent the development of cardiovascular disease. Conversely, data on their effects on non-alcoholic steatohepatitis (NASH) are lacking. We evaluated these effects by feeding APOE*3-Leiden mice a Western-type diet (WTD) with or without atorvastatin to induce NASH and hepatic fibrosis. Besides the well-known plasma cholesterol lowering (-30%) and anti-atherogenic effects (severe lesion size -48%), atorvastatin significantly reduced hepatic steatosis (-22%), the number of aggregated inflammatory cells in the liver (-80%) and hepatic fibrosis (-92%) compared to WTD-fed mice. Furthermore, atorvastatin-treated mice showed less immunohistochemically stained areas of inflammation markers. Atorvastatin prevented accumulation of free cholesterol in the form of cholesterol crystals (-78%). Cholesterol crystals are potent inducers of the NLRP3 inflammasome pathway and atorvastatin prevented its activation, which resulted in reduced expression of the pro-inflammatory cytokines interleukin (IL)-1β (-61%) and IL-18 (-26%). Transcriptome analysis confirmed strong reducing effects of atorvastatin on inflammatory mediators, including NLRP3, NFκB and TLR4. The present study demonstrates that atorvastatin reduces hepatic steatosis, inflammation and fibrosis and prevents cholesterol crystal formation, thereby precluding NLRP3 inflammasome activation. This may render atorvastatin treatment as an attractive approach to reduce NAFLD and prevent progression into NASH in dyslipidemic patients.

Alirocumab, evinacumab, and atorvastatin triple therapy regresses plaque lesions and improves lesion composition in mice

Atherosclerosis-related CVD causes nearly 20 million deaths annually. Most patients are treated after plaques develop, so therapies must regress existing lesions. Current therapies reduce plaque volume, but targeting all apoB-containing lipoproteins with intensive combinations that include alirocumab or evinacumab, monoclonal antibodies against cholesterol-regulating proprotein convertase subtilisin/kexin type 9 and angiopoietin-like protein 3, may provide more benefit. We investigated the effect of such lipid-lowering interventions on atherosclerosis in APOE*3-Leiden.CETP mice, a well-established model for hyperlipidemia. Mice were fed a Western-type diet for 13 weeks and thereafter matched into a baseline group (euthanized at 13 weeks) and five groups that received diet alone (control) or with treatment [atorvastatin; atorvastatin and alirocumab; atorvastatin and evinacumab; or atorvastatin, alirocumab, and evinacumab (triple therapy)] for 25 weeks. We measured effects on cholesterol levels, plaque composition and morphology, monocyte adherence, and macrophage proliferation. All interventions reduced plasma total cholesterol (37% with atorvastatin to 80% with triple treatment; all P < 0.001). Triple treatment decreased non-HDL-C to 1.0 mmol/l (91% difference from control; P < 0.001). Atorvastatin reduced atherosclerosis progression by 28% versus control (P < 0.001); double treatment completely blocked progression and diminished lesion severity. Triple treatment regressed lesion size versus baseline in the thoracic aorta by 50% and the aortic root by 36% (both P < 0.05 vs. baseline), decreased macrophage accumulation through reduced proliferation, and abated lesion severity. Thus, high-intensive cholesterol-lowering triple treatment targeting all apoB-containing lipoproteins regresses atherosclerotic lesion area and improves lesion composition in mice, making it a promising potential approach for treating atherosclerosis.

Oncostatin M reduces atherosclerosis development in APOE*3Leiden.CETP mice and is associated with increased survival probability in humans

Objective

Previous studies indicate a role for Oncostatin M (OSM) in atherosclerosis and other chronic inflammatory diseases for which inhibitory antibodies are in development. However, to date no intervention studies with OSM have been performed, and its relation to coronary heart disease (CHD) has not been studied.

Approach and results

Gene expression analysis on human normal arteries (n = 10) and late stage/advanced carotid atherosclerotic arteries (n = 127) and in situ hybridization on early human plaques (n = 9) showed that OSM, and its receptors, OSM receptor (OSMR) and Leukemia Inhibitory Factor Receptor (LIFR) are expressed in normal arteries and atherosclerotic plaques. Chronic OSM administration in APOE*3Leiden.CETP mice (n = 15/group) increased plasma E-selectin levels and monocyte adhesion to the activated endothelium independently of cholesterol but reduced the amount of inflammatory Ly-6C^High monocytes and atherosclerotic lesion size and severity. Using aptamer-based proteomics profiling assays high circulating OSM levels were shown to correlate with post incident CHD survival probability in the AGES‐Reykjavik study (n = 5457).

Conclusions

Chronic OSM administration in APOE*3Leiden.CETP mice reduced atherosclerosis development. In line, higher serum OSM levels were correlated with improved post incident CHD survival probability in patients, suggesting a protective cardiovascular effect.

Ultrasound Microbubble Delivery Targeting Intraplaque Neovascularization Inhibits Atherosclerotic Plaque in an APOE-deficient Mouse Model

BACKGROUND/AIM

Intraplaque neovascularization is often associated with plaque formation, development and instability, and clinical symptoms in atherosclerosis. The aim of the present study was to investigate a new strategy for treating athrosclerosis by ultrasound-targeted microbubble delivery (UTMD) targeting intraplaque neovascularization in an APOE-deficient mouse model of atherosclerosis.

MATERIALS AND METHODS

A mouse model of atherosclerosis was induced by feeding Apoe^-/- mice a hypercholesterolemic diet and was verified with hematoxylin and eosin staining and intercellular adhesion molecule 1 (ICAM-1) expression. Targeted microbubbles (MB) were prepared by conjugating microbubbles with biotinylated antibody to ICAM1 (MBi) or with both biotinylated anti-ICAM1 and the angiogenesis inhibitor Endostar (MBie). The targeted microbubbles were analyzed with epifluorescence microscopy and flow cytometry. The animals with induced atherosclerotic plaques received MBi or MBie followed by UTMD treatment. Endostar treatment alone was given to other animals for comparison. Morphological assessment of atherosclerotic plaques was performed after treatment. The expression of angiogenesis marker CD31 was detected by immunohistochemical analysis.

RESULTS

Atherosclerotic plaques developed in the entire aorta with significant intraplaque ICAM-1 expression in the APOE-deficient mice following a 30-week hypercholesterolemic diet. Microbubbles were successfully conjugated with anti-ICAM-1 and Endostar, with a conjugation rate of 98.3% and 63.5%, respectively. UTMD with MBie significantly reduced the area of atherosclerotic plaque as compared to the model control (p<0.05). Treatment with Endostar and UTMD with MBie significantly reduced CD31 expression compared with the model control group (p<0.01). Greater significant inhibitory effect on CD31 expression was found in the group treated with UTMD and MBie compared to the Endostar- and UTMD with MBi groups (p<0.01).

CONCLUSION

UTMD targeting intraplaque neovascularization was found to inhibit atherosclerotic plaque in a mouse model of atherosclerosis, suggesting the potential of microbubble-mediated ultrasound technology in aiding drug delivery for atherosclerosis treatment.

The BCR-ABL1 Inhibitors Imatinib and Ponatinib Decrease Plasma Cholesterol and Atherosclerosis, and Nilotinib and Ponatinib Activate Coagulation in a Translational Mouse Model

Treatment with the second and third generation BCR-ABL1 tyrosine kinase inhibitors (TKIs) increases cardiovascular risk in chronic myeloid leukemia (CML) patients. We investigated the vascular adverse effects of three generations of TKIs in a translational model for atherosclerosis, the APOE*3Leiden.CETP mouse. Mice were treated for sixteen weeks with imatinib (150 mg/kg BID), nilotinib (10 and 30 mg/kg QD) or ponatinib (3 and 10 mg/kg QD), giving similar drug exposures as in CML-patients. Cardiovascular risk factors were analyzed longitudinally, and histopathological analysis of atherosclerosis and transcriptome analysis of the liver was performed. Imatinib and ponatinib decreased plasma cholesterol (imatinib, −69%, p < 0.001; ponatinib 3 mg/kg, −37%, p < 0.001; ponatinib 10 mg/kg−44%, p < 0.001) and atherosclerotic lesion area (imatinib, −78%, p < 0.001; ponatinib 3 mg/kg, −52%, p = 0.002; ponatinib 10 mg/kg, −48%, p = 0.006), which were not affected by nilotinib. In addition, imatinib increased plaque stability. Gene expression and pathway analysis demonstrated that ponatinib enhanced the mRNA expression of coagulation factors of both the contact activation (intrinsic) and tissue factor (extrinsic) pathways. In line with this, ponatinib enhanced plasma levels of FVII, whereas nilotinib increased plasma FVIIa activity. While imatinib showed a beneficial cardiovascular risk profile, nilotinib and ponatinib increased the cardiovascular risk through induction of a pro-thrombotic state.

Innovative pharmaceutical interventions in cardiovascular disease: Focusing on the contribution of non-HDL-C/LDL-C-lowering versus HDL-C-raising: A systematic review and meta-analysis of relevant preclinical studies and clinical trials

Non-HDL-cholesterol is well recognised as a primary causal risk factor in cardiovascular disease. However, despite consistent epidemiological evidence for an inverse association between HDL-C and coronary heart disease, clinical trials aimed at raising HDL-C (AIM-HIGH, HPS2-THRIVE, dal-OUTCOMES) failed to meet their primary goals. This systematic review and meta-analysis investigated the effects of established and novel treatment strategies, specifically targeting HDL, on inhibition of atherosclerosis in cholesteryl ester transfer protein-expressing animals, and the prevention of clinical events in randomised controlled trials. Linear regression analyses using data from preclinical studies revealed associations for TC and non-HDL-C and lesion area (R(2)=0.258, P=0.045; R(2)=0.760, P<0.001), but not for HDL-C (R(2)=0.030, P=0.556). In clinical trials, non-fatal myocardial infarction risk was significantly less in the treatment group with pooled odd ratios of 0.87 [0.81; 0.94] for all trials and 0.85 [0.78; 0.93] after excluding some trials due to off-target adverse events, whereas all-cause mortality was not affected (OR 1.05 [0.99-1.10]). Meta-regression analyses revealed a trend towards an association between between-group differences in absolute change from baseline in LDL-C and non-fatal myocardial infarction (P=0.066), whereas no correlation was found for HDL-C (P=0.955). We conclude that the protective role of lowering LDL-C and non-HDL-C is well-established. The contribution of raising HDL-C on inhibition of atherosclerosis and the prevention of cardiovascular disease remains undefined and may be dependent on the mode of action of HDL-C-modification. Nonetheless, treatment strategies aimed at improving HDL function and raising apolipoprotein A-I may be worth exploring.

The therapeuatic effect of Endostar on soft carotid plaque neovascularization in patients with non-small cell lung cancer

The purpose of this study was to investigate the effect of the angiogenesis inhibitor Endostar on carotid plaque neovascularization in patients with non-small cell lung cancer (NSCLC) using contrast-enhanced ultrasound (CEUS). Ninety-one patients who had NSCLC with soft carotid plaques were selected for treatment either with the NP regimen (vinorelbine + cisplatin) (43 patients) or with the ENP regimen (Endostar + NP) (48 patients). Plaque thickness and neovascularization of the plaque were assessed before and at 1 month after treatment using CEUS. Enhanced intensity (EI) of CEUS was used for quantification of plaque neovascularization. There was no significant changes in any group in thickness of plaque between recruitment and 1 month after treatment (P > 0.05 for all). There was no significant change in the EI of plaque in the controls or NP groups at 1 month after treatment (P > 0.05), while EI in the ENP group was significantly reduced at 1 month after treatment (P < 0.01) and significantly lower than that in the controls or NP group at 1 month after treatment (P < 0.001 both). This study indicates that carotid soft plaque neovascularization in patients with NSCLC can be reduced by anti-angiogenesis treatment.

PCSK9 inhibition fails to alter hepatic LDLR, circulating cholesterol, and atherosclerosis in the absence of ApoE

LDL cholesterol (LDL-C) contributes to coronary heart disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases LDL-C by inhibiting LDL-C clearance. The therapeutic potential for PCSK9 inhibitors is highlighted by the fact that PCSK9 loss-of-function carriers exhibit 15-30% lower circulating LDL-C and a disproportionately lower risk (47-88%) of experiencing a cardiovascular event. Here, we utilized pcsk9(-/-) mice and an anti-PCSK9 antibody to study the role of the LDL receptor (LDLR) and ApoE in PCSK9-mediated regulation of plasma cholesterol and atherosclerotic lesion development. We found that circulating cholesterol and atherosclerotic lesions were minimally modified in pcsk9(-/-) mice on either an LDLR- or ApoE-deficient background. Acute administration of an anti-PCSK9 antibody did not reduce circulating cholesterol in an ApoE-deficient background, but did reduce circulating cholesterol (-45%) and TGs (-36%) in APOE*3Leiden.cholesteryl ester transfer protein (CETP) mice, which contain mouse ApoE, human mutant APOE3*Leiden, and a functional LDLR. Chronic anti-PCSK9 antibody treatment in APOE*3Leiden.CETP mice resulted in a significant reduction in atherosclerotic lesion area (-91%) and reduced lesion complexity. Taken together, these results indicate that both LDLR and ApoE are required for PCSK9 inhibitor-mediated reductions in atherosclerosis, as both are needed to increase hepatic LDLR expression.

Anacetrapib reduces progression of atherosclerosis, mainly by reducing non-HDL-cholesterol, improves lesion stability and adds to the beneficial effects of atorvastatin

BACKGROUND

The residual risk that remains after statin treatment supports the addition of other LDL-C-lowering agents and has stimulated the search for secondary treatment targets. Epidemiological studies propose HDL-C as a possible candidate. Cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from atheroprotective HDL to atherogenic (V)LDL. The CETP inhibitor anacetrapib decreases (V)LDL-C by ∼15-40% and increases HDL-C by ∼40-140% in clinical trials. We evaluated the effects of a broad dose range of anacetrapib on atherosclerosis and HDL function, and examined possible additive/synergistic effects of anacetrapib on top of atorvastatin in APOE*3Leiden.CETP mice.

METHODS AND RESULTS

Mice were fed a diet without or with ascending dosages of anacetrapib (0.03; 0.3; 3; 30 mg/kg/day), atorvastatin (2.4 mg/kg/day) alone or in combination with anacetrapib (0.3 mg/kg/day) for 21 weeks. Anacetrapib dose-dependently reduced CETP activity (-59 to -100%, P < 0.001), thereby decreasing non-HDL-C (-24 to -45%, P < 0.001) and increasing HDL-C (+30 to +86%, P < 0.001). Anacetrapib dose-dependently reduced the atherosclerotic lesion area (-41 to -92%, P < 0.01) and severity, increased plaque stability index and added to the effects of atorvastatin by further decreasing lesion size (-95%, P < 0.001) and severity. Analysis of covariance showed that both anacetrapib (P < 0.05) and non-HDL-C (P < 0.001), but not HDL-C (P = 0.76), independently determined lesion size.

CONCLUSION

Anacetrapib dose-dependently reduces atherosclerosis, and adds to the anti-atherogenic effects of atorvastatin, which is mainly ascribed to a reduction in non-HDL-C. In addition, anacetrapib improves lesion stability.

Alirocumab inhibits atherosclerosis, improves the plaque morphology, and enhances the effects of a statin

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition is a potential novel strategy for treatment of CVD. Alirocumab is a fully human PCSK9 monoclonal antibody in phase 3 clinical development. We evaluated the antiatherogenic potential of alirocumab in APOE*3Leiden.CETP mice. Mice received a Western-type diet and were treated with alirocumab (3 or 10 mg/kg, weekly subcutaneous dosing) alone and in combination with atorvastatin (3.6 mg/kg/d) for 18 weeks. Alirocumab alone dose-dependently decreased total cholesterol (−37%; −46%, P < 0.001) and TGs (−36%; −39%, P < 0.001) and further decreased cholesterol in combination with atorvastatin (−48%; −58%, P < 0.001). Alirocumab increased hepatic LDL receptor protein levels but did not affect hepatic cholesterol and TG content. Fecal output of bile acids and neutral sterols was not changed. Alirocumab dose-dependently decreased atherosclerotic lesion size (−71%; −88%, P < 0.001) and severity and enhanced these effects when added to atorvastatin (−89%; −98%, P < 0.001). Alirocumab reduced monocyte recruitment and improved the lesion composition by increasing the smooth muscle cell and collagen content and decreasing the macrophage and necrotic core content. Alirocumab dose-dependently decreases plasma lipids and, as a result, atherosclerosis development, and it enhances the beneficial effects of atorvastatin in APOE*3Leiden.CETP mice. In addition, alirocumab improves plaque morphology.

Osteoarthritis development is induced by increased dietary cholesterol and can be inhibited by atorvastatin in APOE*3Leiden.CETP mice--a translational model for atherosclerosis

OBJECTIVE

Hypercholesterolaemia, a risk factor for atherosclerosis (ATH), has been suggested to have a role in the development of osteoarthritis (OA). To test this hypothesis, the effect of cholesterol and different cholesterol-lowering treatments on OA was investigated in a mouse model resembling human lipoprotein metabolism.

METHODS

Female ApolipoproteinE*3Leiden.human Cholesteryl Ester Transfer Protein mice received a western-type diet with 0.1% (w/w) cholesterol (LC), 0.3% (w/w) cholesterol alone (HC) or treated with 3 mg/kg/day atorvastatin or 0.3 mg/kg/day ezetimibe. One group remained on chow (control). After 39 weeks, OA grades of the knees and the extent of ATH were determined. Plasma cholesterol levels were measured throughout the study.

RESULTS

LC and HC groups developed significantly more OA at the medial side than the control group in a dose-dependent manner. Atorvastatin but not ezetimibe treatment significantly suppressed OA development. As expected, features of ATH were significantly increased in the LC and HC groups compared with the control group and suppressed by atorvastatin (48%) and ezetimibe (55%) treatment. There were significant correlations between the development of OA on the medial side of the joint and cholesterol exposure (r=0.4) or ATH features (r=0.3).

CONCLUSIONS

Dietary cholesterol and accordingly increased plasma levels play a role in the development of OA. The correlation found between OA, cholesterol and ATH demonstrates that these variables are connected, but indicates the contribution of other ongoing processes in the development of OA. The suppressive effect on OA development of atorvastatin but not of ezetimibe, which had similar cholesterol exposure levels, corroborates these findings.

The Renin-Angiotensin-aldosterone system in vascular inflammation and remodeling

The RAAS through its physiological effectors plays a key role in promoting and maintaining inflammation. Inflammation is an important mechanism in the development and progression of CVD such as hypertension and atherosclerosis. In addition to its main role in regulating blood pressure and its role in hypertension, RAAS has proinflammatory and profibrotic effects at cellular and molecular levels. Blocking RAAS provides beneficial effects for the treatment of cardiovascular and renal diseases. Evidence shows that inhibition of RAAS positively influences vascular remodeling thus improving CVD outcomes. The beneficial vascular effects of RAAS inhibition are likely due to decreasing vascular inflammation, oxidative stress, endothelial dysfunction, and positive effects on regeneration of endothelial progenitor cells. Inflammatory factors such as ICAM-1, VCAM-1, TNFα, IL-6, and CRP have key roles in mediating vascular inflammation and blocking RAAS negatively modulates the levels of these inflammatory molecules. Some of these inflammatory markers are clinically associated with CVD events. More studies are required to establish long-term effects of RAAS inhibition on vascular inflammation, vascular cells regeneration, and CVD clinical outcomes. This review presents important information on RAAS's role on vascular inflammation, vascular cells responses to RAAS, and inhibition of RAAS signaling in the context of vascular inflammation, vascular remodeling, and vascular inflammation-associated CVD. Nevertheless, the review also equates the need to rethink and rediscover new RAAS inhibitors.

Role of aliskiren on arterial stiffness and endothelial function in patients with primary hypertension

Arterial stiffness and endothelial dysfunction are important determinants of cardiovascular events in patients with arterial hypertension. There are few data regarding the role of aliskiren on the central hemodynamics and endothelial function in patients with uncontrolled arterial hypertension. The aim of this study was to assess the addition of aliskiren to other antihypertensive drug treatment for arterial stiffness and endothelial function. Thirty uncontrolled hypertensive patients (mean age, 60.4±12.2 years), without any other cardiovascular risk factors, were enrolled. Augmentation index (AIx) and carotid-femoral pulse wave velocity (cfPWV) by applanation tonometry and reactive hyperemia peripheral arterial tonometry (RH PAT) index using peripheral arterious tonometry at baseline and after 6 months of aliskiren titrated to 300 mg once a day was evaluated. The addition of aliskiren had no effect on values of central AIx (33.26±10.74% vs 28.86±10.74%; P=.36) but did significantly improve values of cfPWV (9.36±2.65 m/s vs 8.72±2.48 m/s; P=.04) and RH PAT index (1.64±0.57 vs 1.75±0.45; P=.05). In addition to improving systolic and diastolic blood pressure, the addition of aliskiren to concomitant antihypertensive drugs in uncontrolled hypertensive patients may be effective in improving aortic stiffness and endothelial function. These results encourage further studies to evaluate the use of aliskiren for cardiovascular prevention.

Renin-sensitive microRNAs correlate with atherosclerosis plaque progression

Recent trials with inhibition of the renin-angiotensin-aldosterone system (RAAS) in patients with established atherosclerosis have been equivocal. MicroRNAs (miRs) are known to affect multiple pathways relevant to atherosclerosis, including RAAS. We postulated that the use of a direct renin antagonist would result in differential regulation of miRs. We examined monocyte miR expression before and after treatment with renin antagonist, Aliskiren, in patients with established cardiovascular disease as part of a prospective, single-center, randomized, double-blind and placebo-controlled clinical trial (NCT01417104). After screening, patients (mean age 62±3 years) were randomized to placebo or Aliskiren. Three-dimensional dark-blood magnetic resonance imaging assessment of atherosclerosis in the thoracic and abdominal aorta was conducted at baseline and at study completion (19-36 weeks). MiR expression arrays were performed on RNA from peripheral blood mononuclear cells collected at baseline and 12 weeks following randomization to placebo or Aliskiren and showed that hsa-miR-106b-5p, 27a-3p and 18b-5p were significantly downregulated with Aliskiren. Baseline expression of these miRs positively correlated with normalized total wall volume in subjects taking Aliskiren (miR-106b, R=0.62; miR-27a, R=0.63; miR-18b, R=0.77; P<0.05). Hsa-miR-106b-5p, 27a-3p and 18b-5p may represent pathway-specific adaptations to renin inhibition relevant to atherosclerosis.

Both transient and continuous corticosterone excess inhibit atherosclerotic plaque formation in APOE*3-leiden.CETP mice

Introduction

The role of glucocorticoids in atherosclerosis development is not clearly established. Human studies show a clear association between glucocorticoid excess and cardiovascular disease, whereas most animal models indicate an inhibitory effect of glucocorticoids on atherosclerosis development. These animal models, however, neither reflect long-term glucocorticoid overexposure nor display human-like lipoprotein metabolism.

Aim

To investigate the effects of transient and continuous glucocorticoid excess on atherosclerosis development in a mouse model with human-like lipoprotein metabolism upon feeding a Western-type diet.

Methods

Pair-housed female APOE*3-Leiden.CETP (E3L.CETP) mice fed a Western-type containing 0.1% cholesterol for 20 weeks were given corticosterone (50 µg/ml) for either 5 (transient group) or 17 weeks (continuous group), or vehicle (control group) in the drinking water. At the end of the study, atherosclerosis severity, lesion area in the aortic root, the number of monocytes adhering to the endothelial wall and macrophage content of the plaque were measured.

Results

Corticosterone treatment increased body weight and food intake for the duration of the treatment and increased gonadal and subcutaneous white adipose tissue weight in transient group by +35% and +31%, and in the continuous group by +140% and 110%. Strikingly, both transient and continuous corticosterone treatment decreased total atherosclerotic lesion area by −39% without lowering plasma cholesterol levels. In addition, there was a decrease of −56% in macrophage content of the plaque with continuous corticosterone treatment, and a similar trend was present with the transient treatment.

Conclusion

Increased corticosterone exposure in mice with human-like lipoprotein metabolism has beneficial, long-lasting effects on atherosclerosis, but negatively affects body fat distribution by promoting fat accumulation in the long-term. This indicates that the increased atherosclerosis observed in humans in states of glucocorticoid excess may not be related to cortisol per se, but might be the result of complex indirect effects of cortisol.

Effects of direct renin inhibition on atherosclerotic biomarkers in patients with stable coronary artery disease and type 2 diabetes mellitus

OBJECTIVES

To evaluate whether the direct renin inhibitor, aliskiren, has a more favorable effect compared to amlodipine on atherosclerotic biomarkers in patients with stable coronary artery disease and diabetes currently receiving standard secondary prevention therapy.

METHODS

A total of 38 patients were randomly assigned initially to either aliskiren (150 mg daily) or amlodipine (5 mg daily) for 2 weeks after which the dose of either medication was increased to its maximum daily dose for 4 additional weeks. Baseline and 6-week blood samples were analyzed for changes from baseline and between treatment groups for vascular and intracellular cell adhesion molecule, C-reactive protein, nitric oxide, plasminogen activator inhibitor 1, 8-isoprostane, and thiobarbituric acid reactive substances.

RESULTS

Thirty-one patients completed the study. More of the dropouts occurred in patients receiving aliskiren. Systolic blood pressure decreased in both treatment arms with no differences between the groups being noted. Plasminogen activator inhibitor 1, nitric oxide, and C-reactive protein concentrations increased in both groups from baseline but changes from baseline or between groups were not significant. Vascular and intracellular cell adhesion molecule, thiobarbituric acid reactive substances, and isoprostane concentrations decreased in each treatment arm from baseline, but these changes were not significant and no differences were noted between the groups.

CONCLUSIONS

Treatment with either aliskiren or amlodipine did not significantly alter surrogate biomarkers of atherosclerosis in patients with both diabetes and established cardiovascular disease already receiving appropriate secondary cardiovascular prevention therapy. The study is limited in its size and duration to see an effect.