Statin treatment is associated with reduced toll-like receptor 4 immunohistochemical expression on carotid atherosclerotic plaques: a novel effect of statins

Tongxinluo Capsule Combined with Atorvastatin for Coronary Heart Disease: A Systematic Review and Meta-Analysis

Introduction

Coronary heart disease (CHD) is a common clinical cardiovascular disease, and its morbidity and mortality rates are increasing, which brings a serious burden to the family and society. Dyslipidemia is one of the most important risk factors for CHD. However, it is difficult to reduce blood lipids to an ideal state with the administration of a statin alone. Tongxinluo capsule (TXLC), as a Chinese patent medicine, has received extensive attention in the treatment of CHD in recent years. This systematic review and meta-analysis aim to provide evidence-based medicine for TXLC combined with atorvastatin in the treatment of CHD.

Objective

To evaluate systematically the effectiveness and safety of TXLC combined with atorvastatin in the treatment of CHD.

Methods

Seven English and Chinese electronic databases (PubMed, Cochrane Library, Embase, CNKI, VIP, CBM, and Wanfang) were searched from inception to January 2020, to search for randomized controlled trials (RCTs) on TXLC combined with atorvastatin in the treatment of CHD. Two researchers independently screened the literature according to the literature inclusion and exclusion criteria and performed quality assessment and data extraction on the included RCTs. We performed a systematic review following Cochrane Collaboration Handbook and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and using a measurement tool to assess the methodological quality of systematic reviews (AMSTAR 2). The quality of outcomes was evaluated by the Grading of Recommendations Assessment, Development and Evaluation (GRADE). And meta-analysis was performed by Review Manager 5.2.

Results

A total of 15 RCTs with 1,578 participants were included in this review. Compared to atorvastatin treatment, TXLC combined with atorvastatin treatment showed potent efficacy when it came to the effectiveness of clinical treatment (RR = 1.24; 95% CI, 1.18, 1.29; P < 0.00001), total cholesterol (TC; MD = −1.21; 95% CI, −1.53, −0.89; P < 0.00001), triacylglycerol (TG; MD = −0.73; 95% CI, −0.81, −0.65; P < 0.00001), high-density lipoprotein cholesterol (HDL-C; MD = 0.27; 95% CI, 0.23, 0.31; P < 0.00001), low-density lipoprotein cholesterol (LDL-C; MD = –0.72; 95% CI, –0.80, −0.64; P < 0.00001), C-reactive protein (CRP; SMD = −2.06; 95% CI, −2.56, −1.57; P < 0.00001), frequency of angina pectoris (SMD = −1.41; 95% CI, −1.97, −0.85; P < 0.00001), duration of angina pectoris (MD = −2.30; 95% CI, −3.39, −1.21; P < 0.0001), and adverse reactions (RR = 0.84; 95% CI, 0.51, 1.39; P=0.50). No serious adverse events or reactions were mentioned in these RCTs. According to the PRISMA guidelines, although all studies were not fully reported in accordance with the checklist item, the reported items exceeded 80% of all items. With the AMSTAR 2 standard, the methodological quality assessment found that 9 studies were rated low quality and 6 studies were rated critically low quality. Based on the results of the systematic review, the GRADE system recommended ranking method was used to evaluate the quality of evidence and the recommendation level. The results showed that the level of evidence was low, and the recommendation intensity was a weak recommendation.

Conclusions

TXLC combined with atorvastatin in the treatment of CHD can effectively improve the effectiveness of clinical treatment, significantly reduce the frequency and duration of angina pectoris, decrease blood lipids, and improve inflammatory factors. However, due to the low quality of the literature included in these studies and the variability of the evaluation methods of each study, there is still a need for a more high-quality, large sample, multicenter clinical randomized control for further demonstration.

Fatty acids: facts vs. fiction

During the last 100 years official dietary guidelines have recommended an increased consumption of fats derived from seeds while decreasing the consumption of traditional fats, especially saturated fats. These recommendations are being challenged by recent studies. Furthermore, the increased use of refining processes in fat production had deleterious health effects. Today, the number of high-quality studies on fatty acids is large enough to make useful recommendations on clinical application and everyday practice. Saturated fats have many beneficial functions and palmitic acid appears to be problematic only when it is synthesized due to excess fructose consumption. Trans fatty acids were shown to be harmful when they are manmade but beneficial when of natural origin. Conjugated linoleic acid has many benefits but the isomer mix that is available in supplement form differs from its natural origin and may better be avoided. The ω3 fatty acid linolenic acid has rather limited use as an anti-inflammatory agent - a fact that is frequently overlooked. On the other hand, the targeted use of long chain ω3 fatty acids based on blood analysis has great potential to supplement or even be an alternative to various pharmacological therapies. At the same time ω6 fatty acids like linoleic acid and arachidonic acid have important physiological functions and should not be avoided but their consumption needs to be balanced with long chain ω3 fatty acids. The quality and quantity of these fats together with appropriate antioxidative protection are critical for their positive health effects.

Toll-like receptor 4 (TLR4) antagonists as potential therapeutics for intestinal inflammation

Gastrointestinal inflammation is a hallmark of highly prevalent disorders, including cancer treatment-induced mucositis and ulcerative colitis. These disorders cause debilitating symptoms, have a significant impact on quality of life, and are poorly managed. The activation of toll-like receptor 4 (TLR4) has been proposed to have a major influence on the inflammatory signalling pathways of the intestinal tract. Inhibition of TLR4 has been postulated as an effective way to treat intestinal inflammation. However, there are a limited number of studies looking into the potential of TLR4 antagonism as a therapeutic approach for intestinal inflammation. This review surveyed available literature and reported on the in vitro, ex vivo and in vivo effects of TLR4 antagonism on different models of intestinal inflammation. Of the studies reviewed, evidence suggests that there is indeed potential for TLR4 antagonists to treat inflammation, although only a limited number of studies have investigated treating intestinal inflammation with TLR4 antagonists directly. These results warrant further research into the effect of TLR4 antagonists in the intestinal tract.

Innate Immune Receptors, Key Actors in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death in the industrialized world. Most CVDs are associated with increased inflammation that arises mainly from innate immune system activation related to cardiac damage. Sustained activation of the innate immune system frequently results in maladaptive inflammatory responses that promote cardiovascular dysfunction and remodeling. Much research has focused on determining whether some mediators of the innate immune system are potential targets for CVD therapy. The innate immune system has specific receptors-termed pattern recognition receptors (PRRs)-that not only recognize pathogen-associated molecular patterns, but also sense danger-associated molecular signals. Activation of PRRs triggers the inflammatory response in different physiological systems, including the cardiovascular system. The classic PRRs, toll-like receptors (TLRs), and the more recently discovered nucleotide-binding oligomerization domain-like receptors (NLRs), have been recently proposed as key partners in the progression of several CVDs (e.g., atherosclerosis and heart failure). The present review discusses the key findings related to the involvement of TLRs and NLRs in the progression of several vascular and cardiac diseases, with a focus on whether some NLR subtypes (nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain-containing receptor 3 and nucleotide-binding oligomerization domain-containing protein 1) can be candidates for the development of new therapeutic strategies for several CVDs.

Anti-inflammatory Action of Statins in Cardiovascular Disease: the Role of Inflammasome and Toll-Like Receptor Pathways

Atherosclerosis is one type of cardiovascular disease (CVD) in which activation of the NLRP3 inflammasome and toll-like receptor (TLR) pathways is implicated. One of the most effective treatments for atherosclerosis is the use of statin medications. Recent studies have indicated that statins, in addition to their lipid-lowering effects, exert inhibitory and/or stimulatory effects on the NLRP3 inflammasome and TLRs. Some of the statins lead to activation of the inflammasome and subsequently cause secretion of IL-1β and IL-18. Thus, these actions may further aggravate the disease. On the other hand, some statins cause inhibition of the inflammasome or TLRs and along with lipid-lowering, help to improve the disease by reducing inflammation. In this article, we discuss these contradictory studies and the mechanisms of action of statins on the NLRP3 inflammasome and TLR pathways. The dose-dependent effects of statins on the NLRP3 complex are related to their chemistry, pharmacokinetic properties, and danger signals. Lipophilic statins have more pleiotropic effects on the NLRP3 complex in comparison to hydrophilic statins. Statins can suppress TLR4/MyD88/NF-ĸB signaling and cause an immune response shift to an anti-inflammatory response. Furthermore, statins inhibit the NF-ĸB pathway by decreasing the expression of TLRs 2 and 4. Statins are cost-effective drugs, which should have a continued future in the treatment of atherosclerosis due to both their immune-modulating and lipid-lowering effects.

Systematic review and meta-analysis of perioperative and long-term outcomes in patients receiving statin therapy before carotid endarterectomy

BACKGROUND

Carotid endarterectomy (CEA) is associated with perioperative stroke and mortality in a minority of cases. The aim of this systematic review and meta-analysis was to investigate the effect of pre-operative statins on perioperative outcomes in patients undergoing CEA for internal carotid artery (ICA) stenosis.

METHODS

A systematic review of PubMed, Medline, and the Cochrane Database of Systematic Reviews was performed. Studies were included which reported perioperative stroke and/or survival outcomes following CEA for ICA stenosis and compared patients who were and were not taking pre-operative statins. Relevant data were extracted and pooled using meta-analysis.

RESULTS

Seven studies met the inclusion criteria, comprising 21,387 patients. A total of 68.9% (14,976) were administered statins and 31.1% (6657) were statin-free. Pre-operative statin use was higher in patients with a history of cardiac disease (12.2 vs. 23.6% in the statin-free group), diabetes (31.6 vs. 25.1% in the statin-free group), and hypertension (83.5 vs. 72.2% in the statin-free group), while a greater proportion of statin-free patients had symptomatic disease (44.9 vs. 55.5% in the statin-free group). Statins were associated with reduced perioperative stroke in all patients (OR 0.57; 95% CI 0.34-0.95; p = 0.03) and in symptomatic patients (OR 0.57; 95% CI 0.35-0.93; p = 0.03). A trend towards lower perioperative mortality (OR 0.54; 95% CI 0.29, 1.03; p = 0.06) and significantly improved overall survival was observed in the statin group (HR 0.69; 95% CI 0.59-0.81; p < 0.001) at a mean follow-up of 62 months (range 27-76 months).

CONCLUSIONS

Administration of statins before CEA is associated with lower rates of perioperative stroke and improved overall survival. Compliance with optimal medical treatment associated with the use of pre-operative statins may limit the clinical significance of these findings. Future investigation to characterize the potential benefit of statin therapy in patients undergoing CEA for ICA stenosis is warranted.

Effect of statins on toll-like receptors: a new insight to pleiotropic effects

The toll-like receptors (TLRs) are a class of transmembrane-spanning receptors that are sentinels of both innate and adaptive immunity. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are the most commonly prescribed therapeutic agents for treating hypercholesterolemia globally. However, statin therapy appears to have pleiotropic effects including attenuation of chronic low-grade inflammation and modulation of TLR activity. Statins through abolition of TLR4 expression and regulation of the TLR4/Myd88/NF-κB signaling pathway may slow the progression of atherosclerosis and other inflammatory diseases. In this review, we have focused on the impact and mechanism of action of statins on cardiovascular and non-cardiovascular diseases.

MiR-370 inhibits vascular inflammation and oxidative stress triggered by oxidized low-density lipoprotein through targeting TLR4

Atherosclerosis, as a chronic cardiovascular disease, still remains a serious threat to human health. Inflammation and oxidative stress are commonly involved in various stages of atherosclerosis development. MicroRNAs are reported to play important roles in macrophages, which can respond to inflammation and oxidative stress. In our current study, we focused on the biological roles of miR-370 in atherosclerosis. According to the previously research, miR-370 was downregulated in AS mice models. Oxidized low-density lipoprotein (Ox-LDL) is regarded as a crucial regulator of atherosclerosis and we observed that miR-370 was decreased by ox-LDL dose-dependently and time-dependently in THP-1 cells. Then, it was found that miR-370 overexpression was able to inhibit inflammation molecules including IL-6 and IL-1β. Meanwhile, ROS levels, and malondialdehyde (MDA) were also restrained by miR-370 mimics in vitro. Toll-like receptor 4 (TLR4) has been implicated in many inflammation diseases. It can serve as a target of miR-370 and TLR4 expression was greatly increased in ox-LDL-incubated THP-1 cells in a time and dose dependent manner. The negative correlation was validated using a dual-luciferase reporter assay in our study. In conclusion, our present study revealed that miR-370 can reduce inflammatory reaction and inhibit the ROS production by targeting TLR4 in THP-1 cells.

Favourable impact of statin use on diastolic blood pressure levels: analysis of a large database of 24-hour ambulatory blood pressure monitoring

INTRODUCTION

Assumption of lipid-lowering drugs, mostly statins, is recommended at bed-time and evidence demonstrated a strong and independent correlation between night-time blood pressure (BP) and increased risk of cardiovascular events.

AIM

To evaluate the effects of statins on night-time BP levels.

METHODS

We analysed data derived from a large cohort of adult individuals, who consecutively underwent home, clinic and ambulatory BP monitoring at our Unit. All BP measurements were performed and BP thresholds were set according to recommendations from European guidelines. Study population was stratified according to statin use.

RESULTS

We included an overall sample of 5634 adult individuals (women 48.9%, age 60.5 ± 11.6 years, BMI 27.0 ± 4.6 kg/m, clinic BP 144.3 ± 18.4/90.9 ± 12.4 mmHg, 24-h BP 130.7 ± 13.4/79.0 ± 9.7 mmHg), among whom 17.3% received and 82.7% did not received statins. Treated outpatients were older, had higher BMI and prevalence of risk factors and comorbidities than those who were untreated (P < 0.001 for all). Patients treated with statins showed lower DBP levels at all BP measurements, including night-time (67.3 ± 9.4 vs. 70.9 ± 9.7 mmHg; P < 0.001) periods, than those observed in untreated patients. Also, statin use resulted an independent factor associated with 24-h [odds ratio (95% confidence interval): 1.513(1.295-1.767); P < 0.001] and night-time [odds ratio (95% confidence interval): 1.357(1.161-1.587); P < 0.001] BP control, even after adjusting for age, sex, BMI, diabetes, number of antihypertensive drugs (model 1) or presence/absence of antihypertensive treatment (model 2).

CONCLUSION

Statin use was associated with significantly lower DBP levels. These effects were independently observed, even after correction for cardiovascular risk factors and comorbidities, as well as number of antihypertensive drugs.

miR-223 Inhibits Lipid Deposition and Inflammation by Suppressing Toll-Like Receptor 4 Signaling in Macrophages

Atherosclerosis and its complications rank as the leading cause of death with the hallmarks of lipid deposition and inflammatory response. MicroRNAs (miRNAs) have recently garnered increasing interests in cardiovascular disease. In this study, we investigated the function of miR-223 and the underlying mechanism in atherosclerosis. In the atherosclerotic ApoE^−/− mice models, an obvious increase of miR-223 was observed in aortic atherosclerotic lesions. In lipopolysaccharide (LPS) activated macrophages, its expression was decreased. The miR-223 overexpression significantly attenuated macrophage foam cell formation, lipid accumulation and pro-inflammatory cytokine production, which were reversed by anti-miR-223 inhibitor transfection. Mechanism assay corroborated that miR-223 negatively regulated the activation of the toll-like receptor 4 (TLR4)-nuclear factor-κB (NF-κB) pathway. Pretreatment with a specific inhibitor of NF-κB (pyrrolidinedithiocarbamate, PDTC) strikingly abrogated miR-223 silence-induced lipid deposition and inflammatory cytokine production. Furthermore, PI3K/AKT was activated by miR-223 up-regulation. Pretreatment with PI3K/AKT inhibitor LY294002 strikingly ameliorated the inhibitory effects of miR-223 on the activation of TLR4 and p65, concomitant with the increase in lipid deposition and inflammatory cytokine production. Together, these data indicate that miR-223 up-regulation might abrogate the development of atherosclerosis by blocking TLR4 signaling through activation of the PI3K/AKT pathway, and provides a promising therapeutic avenue for the treatment of atherosclerosis.

Qingre quyu granule stabilizes plaques through inhibiting the expression of tenascin-C in patients with severe carotid stenosis

OBJECTIVE

To investigate the therapeutic effects of Qingre Quyu Granule (QQG) on the patients with severe carotid stenosis, and to explore the mechanism of it.

METHODS

Ninety-six patients with severe carotid stenosis were enrolled in the study and were classified into a QQG group (n=48) and a control group (n=48) randomly using consecutively numbered envelopes. The patients in the QQG group were given QQG and Western medicine, those in the control group were given Western medicine merely, the course of treatment was 16 weeks. All patients went through endarterectomy after treatment. Plaques were subjected to the analysis of CD3, CD68, soluble intercellular adhesion molecule 1 (ICAM-1), matrix metalloprotease-9 (MMP-9), CD40L, tenascin-C, and collagen content lipid content by immunohistochemistry or polarized light analysis.

RESULTS

By the end of experiment, the expressions of CD3, CD68, ICAM-1, MMP9, CD40L and tenascin-C on the plaques were statistically significant lower in the QQG group compared with the control group(P<0.01). The lipid content of the plaque was also significantly lower in the QQG group compared with the control group (P<0.01). The interstitial collagen in the tissue sections of the plaques was also significantly higher in the QQG group in comparison with the control group (P<0.01).

CONCLUSION

QQG could stabilize carotid artery plaques through inhibiting pro-inflammation factors and restraining the tenascin-C and MMP9 pathway.

Macrophage Heterogeneity and Plasticity: Impact of Macrophage Biomarkers on Atherosclerosis

Cardiovascular disease (CVD) is a global epidemic, currently representing the worldwide leading cause of morbidity and mortality. Atherosclerosis is the fundamental pathophysiologic component of CVD, where the immune system plays an essential role. Monocytes and macrophages are key mediators in this aspect: due to their heterogeneity and plasticity, these cells may act as either pro- or anti-inflammatory mediators. Indeed, monocytes may develop heterogeneous functional phenotypes depending on the predominating pro- or anti-inflammatory microenvironment within the lesion, resulting in classic, intermediate, and non-classic monocytes, each with strikingly differing features. Similarly, macrophages may also adopt heterogeneous profiles being mainly M1 and M2, the former showing a proinflammatory profile while the latter demonstrates anti-inflammatory traits; they are further subdivided in several subtypes with more specialized functions. Furthermore, macrophages may display plasticity by dynamically shifting between phenotypes in response to specific signals. Each of these distinct cell profiles is associated with diverse biomarkers which may be exploited for therapeutic intervention, including IL-10, IL-13, PPAR-γ, LXR, NLRP3 inflammasomes, and microRNAs. Direct modulation of the molecular pathways concerning these potential macrophage-related targets represents a promising field for new therapeutic alternatives in atherosclerosis and CVD.

The effect of statin therapy withdrawal on monocyte subsets

BACKGROUND

Three functionally distinct monocyte subsets have been identified. Statins are of undoubted effect in atherosclerosis and have numerous pleiotropic effects that contribute to their clinical success, but the effect of these drugs on monocyte subsets is unclear. We hypothesised a beneficial effect of statins on key receptor expression by monocyte subsets.

MATERIAL AND METHODS

Effects of temporal (2 weeks) cessation of statin therapy by 66 patients with stable coronary artery disease on monocyte subsets [CD14++CD16-CCR2+ (Mon1), CD14++CD16+CCR2+ (Mon2) and CD14+CD16++CCR2- (Mon3)], their aggregates with platelets and their expression of a number of receptors involved in inflammation (IL-6 receptor), adhesion [vascular cell adhesion molecule (VCAM)], angiogenesis [vascular endothelial growth factor (VEGF)] and repair were assessed by flow cytometry.

RESULTS

Statin cessation did not lead to any significant changes in absolute numbers of monocyte subsets or the degree of their aggregation with platelets. All monocyte subsets showed significant downregulation of expression of vascular endothelial factor receptor 2, Tie2 and Toll-like receptor-4 (TLR4; all changes P < 0·01). Expression of CXCR4 was only reduced in Mon1 cells (P = 0·013). There was no significant change in the expression of CD14, CD16, CCR4, IL6 receptor and VCAM (all P = NS).

CONCLUSIONS

Statin withdrawal does not affect counts of any of monocyte subsets, but leads to downregulation of expression of TLR4 and receptors related to angiogenesis on all subsets, as well as a decrease in density of CXCR4 expression on 'classical' Mon1. These data provide further support of pleiotropic effects of statins and their effects on monocyte pro-angiogenic and proreparative characteristics.

Compliance and echographic carotid plaque evolution in patients with acute ischemic stroke treated with atorvastatin according to usual care

The aim of the paper is to assess the compliance and efficacy of atorvastatin treatment according to usual care on carotid atheromatous plaque and lipids during follow-up for one year in patients with acute ischemic stroke. Sixty-six patients were included. Morphological plaque characteristics were described and a complete blood analysis was performed at admission and at one year. Nineteen patients stopped treatment. Lipid reduction was significant in triglycerides, cholesterol and LDL cholesterol, with an increase in HDL cholesterol. Morphological characteristics of carotid plaque were not modified. In conclusion, an irregular compliance has been seen in patients with acute ischemic stroke treated with atorvastatin according to usual care. Nearly one-third of our patients stopped the treatment before the course of a year. The effect on lipids and its pleiotropic effect on atheromatous carotid artery disease might support the long-term use of atorvastatin, regardless of the dose, in patients with acute ischemic stroke.