Plaque-stabilizing effect of angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker in a rabbit plaque model

Angiotensin Receptor-Neprilysin Inhibitor Effects on Atherosclerotic Cardiovascular Disease Events: A Meta-Analysis of Randomized Controlled Trials

Sacubitril-valsartan is an angiotensin receptor-neprilysin inhibitor (ARNI) associated with a decreased risk of death and hospitalization for selected patients with heart failure (HF). However, its association with improved atherosclerotic cardiovascular disease (ASCVD) events remains unclear. We performed a meta-analysis to evaluate the association of ARNI with ASCVD events in patients with HF. We systematically searched PubMed, Embase, Cochrane, and ClinicalTrials.gov for studies comparing ARNIs with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) in terms of myocardial infarction, stroke, angina pectoris, peripheral artery disease, and the composite end point in patients with HF. A total of 8 randomized controlled trials were included, with 17,541 patients assigned to either the ARNI (8,764 patients) or ACEi/ARB (8,777 patients) groups. The incidence of composite end point (risk ratio [RR] 1.03, 95% confidence interval [CI] 0.93 to 1.13, p = 0.63), myocardial infarction (RR 1.02, 95% CI 0.81 to 1.30, p = 0.85), angina pectoris (RR 0.96, 95% CI 0.80 to 1.17, p = 0.70), and stroke (RR 0.99, 95% CI 0.85 to 1.16, p = 0.93) were not statistically different between the ARNI and ACEi/ARB groups. However, ARNI was associated with a higher incidence of peripheral artery disease (RR 1.63, 95% CI 1.05 to 2.52, p = 0.03). In conclusion, this meta-analysis found no association between ARNI therapy and improved ASCVD events in patients with HF.

The immunomodulatory effects of antihypertensive therapy: A review

Hypertension remains the leading preventable risk factor for stroke and coronary artery disease, significantly contributing to all-cause global mortality and predisposing patients to renal and heart failure, as well as peripheral vascular disease. Due to the widespread usage of antihypertensive drugs, global mean blood pressure has remained unchanged or even slightly decreased over the past four decades. However, considering the broad spectrum of mechanisms involved in the action of antihypertensive drugs and the prevalence of their target receptors on immune cells, possible immunomodulatory effects which may exert beneficial effects of lowering blood pressure but also potentially alter immune function should be considered. In this review, we attempt to assess the consequences to immune system function of administering the five most commonly prescribed groups of antihypertensive drugs and to explain the mechanisms behind those interactions. Finally, we show potential gaps in our understanding of the effects of antihypertensive drugs on patient health. With regard to the widespread use of these drugs in the adult population worldwide, the discussed results may be of vital importance to evidence-based decision-making in daily clinical practice.

Influence of myocardial bridge on atherosclerotic plaque distribution and characteristics evaluated by near-infrared spectroscopy intravascular ultrasound

BACKGROUND

This study aims to clarify whether myocardial bridge (MB) could influence atherosclerotic plaque characteristics assessed using near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) imaging.

METHODS

One hundred and sixteen patients who underwent percutaneous coronary intervention (PCI) using NIRS-IVUS imaging were included. MB was defined as an echo-lucent band surrounding left anterior descending artery (LAD). In MB patients, LAD was divided into three segments: proximal, MB, and distal segments. In non-MB patients, corresponding three segments were defined based on the average length of the above segments. Segmental maximum plaque burden and lipid content derived from NIRS-IVUS imaging in the section of maximum plaque burden were evaluated in each segment. Lipid content of atherosclerotic plaque was evaluated as lipid core burden index (LCBI) and maxLCBI_4mm. LCBI is the fraction of pixels indicating lipid within a region multiplied by 1000, and the maximum LCBI in any 4-mm region was defined as maxLCBI_4mm.

RESULTS

MB was identified in 42 patients. MB was not associated with maximum plaque burden in proximal segment. LCBI and maxLCBI_4mm were significantly lower in patients with MB than those without in proximal segment. Multivariable analysis demonstrated both MB and maximum plaque burden in proximal segment to be independent predictors of LCBI in proximal segment.

CONCLUSIONS

Lipid content of atherosclerotic plaque assessed by NIRS-IVUS imaging was significantly smaller in patients with MB than those without. MB could be considered as a predictor of lipid content of atherosclerotic plaque when assessed by NIRS-IVUS imaging.

Effects of Valsartan on Restenosis in Patients with Arteriosclerosis Obliterans of the Lower Extremities Undergoing Interventional Therapy: A Prospective, Randomized, Single-Blind Trial

BACKGROUND The aim of this study was to further clarify the effects of valsartan on restenosis in patients with arteriosclerosis obliterans of the lower extremities. MATERIAL AND METHODS Patients with arteriosclerosis obliterans of the lower extremities undergoing continuous stent implantation in the superficial femoral artery were enrolled and randomly divided into an ARB group and a control group. Patients in the ARB group received valsartan orally in a single-blind manner and were followed up for 6 months. An evaluation was performed based on the criteria for clinical efficacies designed by the Committee of Vascular Disease, Chinese Association of Integrative Medicine. The total clinical effective rate was calculated, and ankle brachial index (ABI) of the patients was assessed. The concentrations of interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP) were measured using enzyme-linked immunosorbent assay. The in-stent restenosis of patients was examined by angiography. RESULTS One patient in the control group died due to acute cerebral hemorrhage 4 months after enrollment, and 1 patient was lost to follow-up due to acute myocardial infarction during follow-up 5 months after enrollment. Age, sex, Fontaine stage, and underlying diseases were comparable between the 2 groups. Hs-CRP (3.93±1.43) and IL-6 (11.26±2.29) levels were significant different in the ARB group compared with the control group. The postoperative follow-up showed that ABI was 0.98±0.20 in the ARB group and 0.62±0.48 in the control group. CONCLUSIONS Valsartan inhibited the increase in hs-CRP and IL-6 levels, improved clinical efficacies, increased ABI, and decreased the restenosis rate after the interventional therapy in patients with arteriosclerosis obliterans of the lower extremities.

Synergistic protective effects of a statin and an angiotensin receptor blocker for initiation and progression of atherosclerosis

Aim

Although the atheroprotective effects of statins and angiotensin II receptor blockers (ARBs) are well-established, little is known about their additive effects, especially during the early period of atherosclerosis. The aim of this study was to investigate whether combination of a statin and an ARB exerts synergistic anti-atherosclerotic effects, and to elucidate the mechanisms of combined effects.

Methods

Atherosclerotic plaques were developed in arteries of 23 rabbits using a high-cholesterol diet (HCD) and intra-arterial balloon inflation. Rabbits received one of five different treatment strategies for 4 weeks: positive control [n = 5, HCD]; negative control [n = 3, regular chow diet]; statin [n = 5, HCD and rosuvastatin 10 mg]; ARB [n = 5, HCD and olmesartan 20 mg]; and combination [n = 5, HCD and statin+ARB].

Results

Histological analysis demonstrated that development of atherosclerotic plaques was inhibited more in combination group than in statin group (P = 0.001). Although macrophage infiltration identified by RAM11 staining was not significantly different between combination and individual treatment groups (31.76±4.84% [combination] vs. 38.11±6.53% [statin; P = 0.35] or 35.14±2.87% [ARB; P = 0.62]), the relative proportion of pro-inflammatory M1-macrophages was significantly lower in combination group than in ARB group (3.20±0.47% vs. 5.20±0.78%, P = 0.02). Furthermore, M2-macrophage polarization was higher in combination group than in statin group (17.70±3.04% vs. 7.86±0.68%, P = 0.001).

Conclusion

Combination treatment with a statin and an ARB produced synergistic protective effects for atherosclerosis initiation and progression, which may be attributed to modulation of macrophage characteristics in the early period of atherosclerosis.

Neprilysin Inhibitor-Angiotensin II Receptor Blocker Combination Therapy (Sacubitril/valsartan) Suppresses Atherosclerotic Plaque Formation and Inhibits Inflammation in Apolipoprotein E- Deficient Mice

We assessed the effects of the sacubitril/valsartan combination drug (LCZ696), in comparison to valsartan alone, on the progression of atherosclerotic plaque formation and inflammatory gene expression in apolipoprotein E- deficient mice (apoE^−/− mice). Seventy-two apoE^−/− mice were fed a western diet and a constrictive silastic tube was used to elicit carotid lesion formation. The animals were separated into a control group, a valsartan group or an LCZ696 group (n = 24 in each group). Plaques in the carotid artery were harvested 12 weeks later for histological examination. The levels of pro-inflammatory genes in the plasma and lesions were detected using real-time PCR and ELISA. Valsartan or LCZ696 treatment remarkably inhibited the expression of pro-inflammatory genes, including interleukin-6, matrix metalloproteinase-8 and monocyte chemotactic protein-1, in comparison with the control group. Meanwhile, both valsartan and LCZ696 suppressed the formation of atherosclerotic plaques by decreasing plaque lipid content and cross-sectional plaque area and increasing the content of plaque collagen and fibrous cap thickness. In particular, LCZ696 performed the best in suppressing atherosclerosis and inhibiting the level of pro-inflammatory genes. LCZ696 significantly ameliorated atherosclerosis and inflammation in apoE^−/− mice compared with valsartan.

Effects of angiotensin receptor blockers on neointimal characteristics in angina patients requiring stent implantation: optical coherence tomography analysis

BACKGROUND

Angiotensin receptor blockers (ARBs) are known for its anti-inflammatory and anti-proliferative effects. The aim of the study was to evaluate long-term effects of ARBs on morphologic characteristics of stent restenosis in patients with coronary artery disease requiring stent implantation by optical coherence tomography (OCT).

METHODS

Patients with coronary artery disease having history of drug-eluting stent implantation (n = 407) were analyzed on the basis of ARB therapy as the ARB group (n = 162) and the non-ARB group (n = 245). Neointimal characterizations were performed at lesions with diameter stenosis >30% with OCT in each group. Major adverse cardiovascular events (MACEs), lumen area, stent area, neointimal area, neointimal thickness, nonapposed struts, uncovered struts, and intraluminal mass between two groups were also observed.

RESULTS

More patients in the ARB group revealed homogeneous and layered neointimal pattern (44.9% vs. 35.6%, P < 0.001, and 16.8% vs. 10.6%, P < 0.001, respectively), and whereas patients in the non-ARB group revealed heterogeneous neointimal pattern (1.1% vs. 7.6%, P < 0.001). Mean neointimal area (1.09 ± 1.00 mm2 vs. 1.38 ± 1.24 mm2) and mean neointimal thickness (140.6 ± 112.0 μm vs. 189.6 ± 423.1 μm) with OCT were smaller in the ARB group when compared to the non-ARB group. Percentage of covered stents was significantly higher in the ARB group when compared to the Non-ARB group (97.3% vs. 92.6%, P = 0.015). Other factors such as follow-up % diameter stenosis, late lumen loss, binary restenosis, MACEs, various neointimal characteristics analyzed by image analyzing software did not show significant differences.

CONCLUSION

The use of ARBs after drug-eluting stent implantation demonstrated difference in neointimal characteristics, less amount of neointimal area and fewer number of uncovered stent struts during the follow-up OCT, indicating the anti-proliferative and anti-inflammatory effects of ARBs.

Identification of Risk Factors Influencing In-Stent Restenosis with Acute Coronary Syndrome Presentation

Although the angiographic rates of in-stent restenosis (ISR) at later months have reduced dramatically with the introduction of drug-eluting stents (DESs), some patients with ISR after implantation of DES present with acute coronary syndrome (ACS). Here, we sought to identify parameters influencing the likelihood of restenosis with ACS presentation after DES implantation. Stented patients (n=3,817) with DESs in the Korea University Anam Hospital percutaneous coronary intervention registry were reviewed retrospectively for inclusion. In this database, 247 age- and sex-matched patients (6.5%) with ISR were allocated to either the Stable ISR group (n=78) or the ACS ISR group (n=73). Predictors of in-stent restenosis were identified with Cox regression analyses. Age (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.02 to 1.27; p=0.026), diabetes (HR, 8.40; 95% CI, 1.30 to 54.1; p=0.025), use of aspirin (HR, 0.003; 95% CI, 0.0001 to 0.63; p=0.03), clopidogrel (HR, 0.005; 95% CI, 0.001 to 0.121; p=0.001), renin-angiotensin system (RAS) blocker (HR, 0.02; 95% CI, 0.003 to 0.14; p<0.001), use of first -generation DES (HR, 0.07; 95% CI, 0.009 to 0.59; p=0.014), and matrix metalloproteinase 2 (MMP-2) levels (HR, 1.120; 95% CI, 1.001 to 1.190; p=0.004) during follow-up angiograms were significant predictors of ISR with ACS presentation during the 3 year follow-up. Age, diabetes, the use of first generation DES, and increased MMP-2 levels were significant predictors of ISR with ACS presentation; moreover, the use of aspirin, clopidogrel, RAS blocker, and the use of second generation DESs prevented ISR with ACS presentation.

Stabilization of high-risk plaques

The prevalence of atherosclerotic cardiovascular diseases (ASCVDs) is increasing globally and they have become the leading cause of death in most countries. Numerous experimental and clinical studies have been conducted to identify major risk factors and effective control strategies for ASCVDs. The development of imaging modalities with the ability to determine the plaque composition enables us to further identify high-risk plaque and evaluate the effectiveness of different treatment strategies. While intensive lipid-lowering by statins can stabilize or even regress plaque by various mechanisms, such as the reduction of lipid accumulation in a necrotic lipid core, the reduction of inflammation, and improvement of endothelial function, there are still considerable residual risks that need to be understood. We reviewed important findings regarding plaque vulnerability and some encouraging emerging approaches for plaque stabilization.

Involvement of Angiotensin II Type 1 and 2 Receptors in Gelatinase Regulation in Human Carotid Atheroma in vitro

AIM

Matrix metalloproteinases (MMPs), angiotensin II (AII) and its receptors are implicated in atherosclerotic plaque instability, however the roles of the two receptor subtypes, ATR1 and ATR2, in MMP regulation remain uncertain. In this study, we investigated the effect of ATR1 and ATR2 blockade on the expression and activity of MMP-2, MMP-3 and MMP-9, in human carotid atheroma.

METHODS

Atheroma samples (n=36) were obtained from patients undergoing carotid endarterectomy. The effects of ATR1 (irbesartan), ATR2 (PD123319) and combined ATR1 and ATR2 blockade on the expression and activity of the MMPs and the expression of tissue inhibitors of metalloproteinases (TIMPs) were investigated in explant culture experiments. Paired atheroma samples were incubated with the intervention or media control for 4 days. Protein levels (MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2, TIMP-4, ATR1 and ATR2) were determined by ELISA. Overall gelatinase activity and specific activation were measured by chromogenic activity assays and zymography, respectively.

RESULTS

ATR1 blockade, but not ATR2 blockade significantly reduced TIMP-1, TIMP-2 and TIMP-4 expression in atheroma supernatant. Combined ATR1 and ATR2 blockade significantly reduced MMP-2, MMP-3 and MMP-9 expression. MMP-2 and MMP-9 relative activation, and overall MMP-9 catalytic capacity were significantly increased by ATR1 blockade.

CONCLUSIONS

Our findings suggest that ATR1 blockade reduces TIMP expression and increases gelatinase activity in human carotid atheroma.