Reduction of In-Stent Restenosis by Cholesteryl Ester Transfer Protein Inhibition

Proteomic Analysis and 2-Hydroxyisobutyrylation Profiling in Metabolic Syndrome Induced Restenosis

Restenosis is the primary complication following stenting for coronary and peripheral arterial disease, posing an ongoing clinical challenge. Metabolic syndrome (MetS), characterized by metabolic disturbances, has been identified as an independent predictor for postoperative restenosis in coronary and carotid arteries, potentially due to endothelial dysfunction and augmented oxidative stress in cells, while its specific regulatory mechanism is still largely unknown. Lysine 2-hydroxyisobutyrylation (Khib), a recently identified posttranslational modification, plays a crucial role in transcriptional regulation and cellular metabolism. However, there is a lack of comprehensive analysis of the proteome and Khib modifications within restenotic vessels in the context of MetS, as well as in the understanding of the associated pathophysiology. In this study, we observed a significant upregulation of Khib in restenotic arteries induced by MetS, confirmed by animal and cellular experiments. Further, using high-throughput liquid chromatography-mass spectrometry, we catalogued 15,558 Khib sites across 2568 proteins, implicating a multitude of biological functions. Analysis revealed 2007 Khib sites on 1002 proteins with considerable differential modifications which are present within the cytoplasm and nucleus. Interestingly, proteins located in the mitochondria, endoplasmic reticulum, and cell membrane also exhibit distinct expression and modification profiles to varying extents that related to vascular smooth muscle contraction, platelet activation, and the PI3K-Akt signaling pathway. Notably, the level of COL1A1 protein detected in the protein-protein interaction pathway network and the level of Khib modification are diametrically opposed, suggesting a significant role in the disease's pathogenesis. This study provides the first comprehensive proteomic and Khib modification overview of MetS-related in-stent restenosis vasculature, offering key insights to inform novel therapeutic approaches for restenosis mitigation.

Using XGBoost for Predicting In-Stent Restenosis Post-DES Implantation: Role of Lymphocyte-to-Monocyte Ratio and Residual Cholesterol

Objective

This study aims to investigate their correlation and predictive utility for in-stent restenosis (ISR) in patients with acute coronary syndrome (ACS) following percutaneous coronary intervention (PCI).

Methods

We collected medical records of 668 patients who underwent PCI treatment from January 2022 to December 2022. Based on follow-up results (ISR defined as luminal narrowing ≥ 50% on angiography), all participants were divided into ISR and non-ISR groups. The XGBoost machine learning (ML) model was employed to identify the optimal predictive variables from a set of 31 variables. Discriminatory ability was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC), while calibration and performance of the prediction models were assessed using the Hosmer-Lemeshow (HL) test and calibration plots. Clinical utility of each model was evaluated using decision curve analysis (DCA).

Results

In the XGBoost importance ranking of predictive factors, LMR and RC ranked first and fourth, respectively. The AUC of the entire XGBoost ML model was 0.8098, whereas the model using traditional stepwise backward regression, comprising five predictive factors, had an AUC of 0.706. The XGBoost model showed superior predictive performance with a higher AUC, indicating better discrimination and predictive accuracy for ISR compared to traditional methods.

Conclusion

LMR and RC are identified as cost-effective and reliable biomarkers for predicting ISR risk in ACS patients following drug-eluting stent (DES) implantation. LMR and RC represent cost-effective and reliable biomarkers for predicting ISR risk in ACS patients following drug-eluting stent implantation. Enhances the accuracy and clinical utility of ISR prediction models, offering clinicians a robust tool for risk stratification and personalized patient management.

MiR-199a-5p Deficiency Promotes Artery Restenosis in Peripheral Artery Disease by Regulating ASMCs Function via Targeting HIF-1α and E2F3

BACKGROUND

Restenosis (RS) poses a significant concern, leading to recurrent ischemia and the potential for amputation following intraluminal angioplasty in the treatment of Peripheral Artery Disease (PAD). Through microRNA microarray analysis, the study detected a significant downregulation of miR-199a-5p within arterial smooth muscle cells (ASMCs) associated with RS.

OBJECTIVE

This research aims to explore the possible function and the underlying mechanisms of miR-199a-5p in the context of RS.

METHODS

Primary ASMCs were extracted from the femoral arteries of both healthy individuals and patients with PAD or RS. The expression levels of miR-199a-5p were assessed using both qRT-PCR and in situ hybridization techniques. To examine the impacts of miR-199a-5p, a series of experiments were performed, including flow cytometry, TUNEL assay, EdU assay, CCK8 assay, Transwell assay, and wound closure assay. A rat carotid balloon injury model was employed to elucidate the mechanism through which miR-199a-5p mitigated neointimal hyperplasia.

RESULTS

MiR-199a-5p exhibited downregulation in RS patients and was predominantly expressed within ASMCs. Elevated the expression of miR-199a-5p resulted in an inhibitory effect of proliferation and migration in ASMCs. Immunohistochemistry and a dual-luciferase reporter assay uncovered that RS exhibited elevated expression levels of both HIF-1α and E2F3, and they were identified as target genes regulated by miR-199a-5p. The co-transfection of lentiviruses carrying HIF-1α and E2F3 alongside miR-199a-5p further elucidated their role in the cellular responses mediated by miR-199a-5p. In vivo, the delivery of miR-199a-5p via lentivirus led to the mitigation of neointimal formation following angioplasty, achieved by targeting HIF-1α and E2F3.

CONCLUSION

MiR-199a-5p exhibits promise as a prospective therapeutic target for RS since it alleviates the condition by inhibiting the proliferation and migration of ASMCs via its regulation of HIF-1α and E2F3.

Predictive Value of COPD History on In-Stent Restenosis in Coronary Arteries Following Percutaneous Coronary Intervention

Objective

Chronic obstructive pulmonary disease (COPD) is a prevalent chronic respiratory disease that poses a significant health risk to individuals. Patients with COPD are predisposed to a higher incidence of coronary artery disease (CAD) than the general population. This study aims to investigate the correlation between COPD and the incidence of in-stent restenosis (ISR) after percutaneous coronary intervention (PCI).

Methods

This study retrospectively analyzed the clinical data and laboratory test results of patients who underwent PCI at our hospital between January 2018 and December 2021 to investigate the relationship between COPD and drug-Eluting Stents (DES) postoperative ISR. We employed the best subset method to select the most suitable combination of predictive factors, utilizing the data, and verified the precision of the model by means of internal validation. We ultimately assessed the performance of the prediction model using an ROC curve.

Results

The research indicates that COPD is an independent risk factor for ISR after PCI (OR=2.437, 95% CI [1.336, 4.495], P=0.004). The analysis revealed an area under the receiver operating characteristic (ROC) curve of 0.783 for the training group and 0.705 for the testing group, indicating a model fitting for both groups (both > 0.5).

Conclusion

COPD history is a dependable predictor of stent restenosis post percutaneous coronary intervention.

Association of serum apoA-I with in-stent restenosis in coronary heart disease

Background

Despite use of drug-eluting stents (DES), in-stent restenosis (ISR) continues adversely affecting clinical outcomes of patients undergoing percutaneous coronary intervention (PCI). Apolipoprotein A-I (apoA-I) has athero-protective effects. However, there is a paucity of clinical data regarding the association between apoA-I and ISR. We sought to investigate whether serum apoA-I is related to ISR after DES-based PCI.

Methods

In this retrospective case control study, 604 consecutive patients who underwent DES implantation before were enrolled. Patients who underwent repeat angiography within 12 months were included in the early ISR study (n = 205), while those beyond 12 months were included in the late ISR study (n = 399). ISR was defined as the presence of > 50% diameter stenosis at the stent site or at its edges. Clinical characteristics were compared between ISR and non-ISR patients in the early and late ISR study, respectively, after adjusting for confounding factors by multivariate logistic regression, stratified analysis, and propensity score matching. The predictive value was assessed by univariate and multivariate logistic regression analysis, receiver operating characteristic (ROC) curve analysis, and quartile analysis.

Results

In the early ISR study, 8.8% (18 of 205) patients developed ISR. Serum apoA-I in the ISR group was lower than that in the non-ISR group (1.1 ± 0.26 vs. 1.24 ± 0.23, P < 0.05). On multivariate logistic regression analysis, apoA-I was an independent risk factor for early ISR. Incidence of early ISR showed negative correlation with apoA-I and could be predicted by the combined use of apoA-I and glycosylated hemoglobin (HbA1c) level. In the late ISR study, 21.8% (87 of 399) patients developed ISR. On subgroup analysis, late ISR showed negative correlation with apoA-I irrespective of intensive lipid lowering; on multivariate logistic regression analysis, apoA-I was also an independent risk factor for late ISR. In patients with intensive lipid lowering, combined use of apoA-I, stenting time, and diabetes predicted the incidence of late ISR.

Conclusions

ApoA-I was an independent risk factor for ISR, and showed a negative correlation with ISR after DES-based PCI. Combined use of apoA-I and clinical indicators may better predict the incidence of ISR under certain circumstances.

Plasma Proteome Profiling of Patients With In-stent Restenosis by Tandem Mass Tag-Based Quantitative Proteomics Approach

Background

Despite the widespread application of new drug-eluting stents, a considerable portion of patients experience in-stent restenosis (ISR). To date, the pathophysiologic mechanisms of ISR remain poorly understood.

Methods

In this study, we collected plasma samples from ISR patients (n = 29) and non-ISR patients (n = 36) after drug-eluting stent implantation, as well as from healthy controls (HCs) (n = 32). Our goal was to investigate differences in plasma protein profiles using tandem mass tag (TMT) labeling coupled with liquid chromatography and tandem mass spectrometry. The proteomic data were validated by enzyme-linked immunosorbent assay (ELISA). Bioinformatic analyses were conducted to analyze potential pathways and protein-protein interaction (PPI) involved in ISR.

Results

A total of 1,696 proteins were identified, of which 278 differed in protein abundance between non-ISR and HCs, 497 between ISR and HCs, and 387 between ISR and non-ISR, respectively. Bioinformatic analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and PPI, further demonstrated that differentially abundant proteins between ISR and non-ISR are involved in several crucial biological processes and signaling pathways, such as focal adhesion, platelet activation, Rap1 signaling, regulation of actin cytoskeleton, and cholesterol metabolism. Among the identified differentially abundant proteins in ISR, 170 were increased in abundance relative to both non-ISR patients and HCs. Some of these proteins were identified to have critical functions for atherosclerosis development and might be involved in ISR pathology. Among these proteins, 3 proteins with increased abundance including fetuin-B, apolipoprotein C-III (APOC3), and cholesteryl ester transfer protein (CETP) were confirmed by ELISA.

Conclusions

This is the first study provided a comprehensive proteomic profile to understand ISR pathology, which may help identify early diagnostic biomarkers and therapeutic targets.

Glycyrrhizic Acid Attenuates Balloon-Induced Vascular Injury Through Inactivation of RAGE Signaling Pathways

Percutaneous coronary intervention is a well-established technique used to treat coronary artery disease, but the risk of coronary artery in-stent restenosis following percutaneous coronary intervention is still high. Previous studies revealed that high mobility group protein B1 (HMGB1) plays a critical role in neointima formation. In this study, we aimed to investigate the role of glycyrrhizic acid (GA), an HMGB1 inhibitor, in the process of neointima formation and the potential mechanisms. We investigated the role of GA in neointima formation through an iliac artery balloon injury model in rabbits. Proliferation, migration, and phenotype transformation of human vascular smooth muscle cells (VSMCs) were observed. Besides, inflammation and receptor for advanced glycosylation end products (RAGE) signaling pathways were studied. The results indicate that GA attenuated neointima formation and downregulated HMGB1 expression in injured artery in rabbits. HMGB1 promoted proliferation, migration, and phenotype transformation through the activation of RAGE signaling pathways in VSMCs, and blockade of HMGB1 by GA (1, 10, and 100 μM) could attenuate those processes and reduce proliferation of human VSMCs. In conclusion, the HMGB1 inhibitor GA might be useful to treat proliferative vascular diseases by downregulating RAGE signaling pathways. Our results indicate a new and promising therapeutic agent for restenosis.

The Cholesteryl Ester Transfer Protein Inhibitor, des-Fluoro-Anacetrapib, Prevents Vein Bypass-induced Neointimal Hyperplasia in New Zealand White Rabbits

Coronary artery bypass grafting is among the most commonly performed of all cardiovascular surgical procedures. However, graft failure due to stenosis reduces the long-term benefit of the intervention. This study asks if elevating plasma high density lipoprotein cholesterol (HDL-C) levels by inhibition of cholesteryl ester transfer protein (CETP) activity with des-fluoro-anacetrapib, an analog of the CETP inhibitor anacetrapib, prevents vein bypass-induced neointimal hyperplasia. NZW rabbits were placed on a normal chow diet or chow containing 0.14% (wt/wt) des-fluoro-anacetrapib for 6 weeks. Bypass grafting of the jugular vein to the common carotid artery was performed 2 weeks after starting dietary des-fluoro-anacetrapib supplementation. The animals were euthanised 4 weeks post-bypass grafting. Relative to control, dietary supplementation with des-fluoro-anacetrapib reduced plasma CETP activity by 89 ± 6.9%, increased plasma apolipoprotein A-I levels by 24 ± 5.5%, increased plasma HDL-C levels by 93 ± 26% and reduced intimal hyperplasia in the grafted vein by 38 ± 6.2%. Des-fluoro-anacetrapib treatment was also associated with decreased bypass grafting-induced endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), endothelial dysfunction, and smooth muscle cell (SMC) proliferation in the grafted vein. In conclusion, increasing HDL-C levels by inhibiting CETP activity is associated with inhibition of intimal hyperplasia in grafted veins, reduced inflammatory responses, improved endothelial function, and decreased SMC proliferation.

High-Density Lipoproteins and Apolipoprotein A-I Improve Stent Biocompatibility

Revascularization because of coronary artery disease is commonly achieved by percutaneous coronary intervention with stent deployment. Refinement in interventional techniques, major improvements in stent design (particularly drug-eluting stents), and adjunctive pharmacotherapy with dual antiplatelet regimens have led to marked reductions in the overall rates of stent failure. However, even with the advancements made in the latest generation of drug-eluting stents, unresolved biological problems persist including delayed re-endothelialization and neoatherosclerosis, which can promote late expansion of the neointima and late stent thrombosis. Novel strategies are still needed beyond what is currently available to specifically address the pathobiological processes that underpin the residual risk for adverse clinical events. This review focuses on the emerging evidence that HDL (high-density lipoproteins) and its main apo (apolipoprotein), apoA-I, exhibit multiple vascular biological functions that are associated with an improvement in stent biocompatibility. HDL/apoA-I have recently been shown to inhibit in-stent restenosis in animal models of stenting and suppress smooth muscle cell proliferation in in vitro studies. Reconstituted HDL also promotes endothelial cell migration, endothelial progenitor cell mobilization, and re-endothelialization. Furthermore, reconstituted HDL decreases platelet activation and HDL cholesterol is inversely associated with the risk of thrombosis. Finally, reconstituted HDL/apoA-I suppresses key inflammatory mechanisms that initiate in-stent neoatherosclerosis and can efflux cholesterol from plaque macrophages, an important function of HDLs that prevents plaque progression. These unique multifunctional effects of HDL/apoA-I suggest that, if translated appropriately, have the potential to improve stent biocompatibility. This may provide an alternate and more efficacious therapeutic pathway for the translation of HDL.

Impaired Cholesterol-Uptake Capacity of HDL Might Promote Target-Lesion Revascularization by Inducing Neoatherosclerosis After Stent Implantation

Background We evaluated the importance of high-density lipoprotein (HDL) functionality for target-lesion revascularization in patients treated with coronary stents using a rapid cell-free assay system to evaluate the functional capacity of HDL to accept additional cholesterol (cholesterol-uptake capacity; CUC). Methods and Results From an optical coherence tomography (OCT) registry of patients treated with coronary stents, 207 patients were enrolled and their HDL was functionally evaluated by measuring the CUC. Follow-up OCT was performed (median duration, 24.5 months after stenting) to evaluate the presence of neoatherosclerosis. Clinical follow-up was performed to assess target-lesion revascularization for a median duration of 42.3 months after stent implantation. Neoatherosclerosis was identified in 37 patients (17.9%). Multivariate logistic regression analysis revealed that a decreased CUC was independently associated with neoatherosclerosis (odds ratio, 0.799; P<0.001). The CUC showed a significant inverse correlation with incidence of target-lesion revascularization (odds ratio, 0.887; P=0.003) and with lipid accumulation inside stents, suggesting that neoatherosclerosis contributes to the association between CUC and target-lesion revascularization. Conclusions Impaired HDL functionality, detected as decreased CUC, might lead to future stent failure by provoking atherogenic changes of the neointima within stents. Both quantitative and qualitative assessments of HDL might enable the improved prediction of clinical outcomes after stent implantation.

The effect of Telmisartan on the expression of connexin43 and neointimal hyperplasia in a rabbit iliac artery restenosis model

We established a rabbit iliac artery restenosis model to explore the impact of Telmisartan on the expression of Connexin43 (Cx43) and neointimal hyperplasia. Thirty New Zealand white rabbits were randomly divided into three groups: control group (n = 10), restenosis group (n = 10), and Telmisartan group (n = 10). The restenosis model was established by high-cholesterol diet combined with double-balloon injury of iliac arteries. In addition, Telmisartan at 5 mg/(kg day) was administered to the rabbits of Telmisartan group on the second day after the second balloon injury. All rabbits were killed at the end of the experiment followed by institution policy. Before sacrifice, blood samples were obtained to test serum angiotensinII (AngII). Iliac arteries were isolated for morphological analysis and determining the expression of Cx43 by HE staining, immunohistochemical analysis, reverse transcription-polymerase chain reaction (RT-PCR), and Western Blotting analysis. Then, the local AngII levels of arteries were measured by radioimmunoassay. As compared with controls, the expression of Cx43 mRNA (0.98 ± 0.08) vs. (1.27 ± 0.17), P < 0.01), and Cx43 protein [(0.75 ± 0.08) vs. (0.90 ± 0.08), P < 0.05] of restenosis group were increased, which were significantly higher than those of Telmisartan group [Cx43 mRNA: (1.27 ± 0.17) vs. (1.00 ± 0.20), P < 0.01; Cx43 protein: (0.90 ± 0.08) vs. (0.82 ± 0.05), P < 0.05]. Furthermore, The intima thickness [(266.12 ± 70.27) vs. (2.85 ± 0.19) μm, P < 0.01] and the local AngII [(115.6 ± 15.7) vs. (90.1 ± 7.7), P < 0.05] of restenosis group were raised when compared with controls. Telmisartan group exhibited thinner intima compared with restenosis group [(68.22 ± 24.37) vs. (266.12 ± 70.27), P < 0.01]. However, the local AngII levels between these two groups were approximate. In addition, the plasma concentration of AngII was not significantly different among three groups. In conclusion, Telmisartan can inhibit the expression of connexin43 and neointimal hyperplasia in iliac artery restenosis model.

Cholesteryl ester transfer protein and its inhibitors

Most of the cholesterol in plasma is in an esterified form that is generated in potentially cardioprotective HDLs. Cholesteryl ester transfer protein (CETP) mediates bidirectional transfers of cholesteryl esters (CEs) and triglycerides (TGs) between plasma lipoproteins. Because CE originates in HDLs and TG enters the plasma as a component of VLDLs, activity of CETP results in a net mass transfer of CE from HDLs to VLDLs and LDLs, and of TG from VLDLs to LDLs and HDLs. As inhibition of CETP activity increases the concentration of HDL-cholesterol and decreases the concentration of VLDL- and LDL-cholesterol, it has the potential to reduce atherosclerotic CVD. This has led to the development of anti-CETP neutralizing monoclonal antibodies, vaccines, and antisense oligonucleotides. Small molecule inhibitors of CETP have also been developed and four of them have been studied in large scale cardiovascular clinical outcome trials. This review describes the structure of CETP and its mechanism of action. Details of its regulation and nonlipid transporting functions are discussed, and the results of the large scale clinical outcome trials of small molecule CETP inhibitors are summarized.

Lipopolysaccharide Lowers Cholesteryl Ester Transfer Protein by Activating F4/80+Clec4f+Vsig4+Ly6C- Kupffer Cell Subsets

BACKGROUND

Lipopolysaccharide (LPS) decreases hepatic CETP (cholesteryl ester transfer protein) expression albeit that the underlying mechanism is disputed. We recently showed that plasma CETP is mainly derived from Kupffer cells (KCs). In this study, we investigated the role of KC subsets in the mechanism by which LPS reduces CETP expression.

METHODS AND RESULTS

In CETP-transgenic mice, LPS markedly decreased hepatic CETP expression and plasma CETP concentration without affecting hepatic macrophage number. This was paralleled by decreased expression of the resting KC markers C-type lectin domain family 4, member f (Clec4f) and V-set and immunoglobulin domain containing 4 (Vsig4), while expression of the infiltrating monocyte marker lymphocyte antigen 6 complex locus C (Ly6C) was increased. Simultaneously, the ratio of plasma high-density lipoprotein-cholesterol over non-high-density lipoprotein-cholesterol transiently increased. After ablation hepatic macrophages via injection with liposomal clodronate, the reappearance of hepatic gene and protein expression of CETP coincided with Clec4f and Vsig4, but not Ly6C. Double-immunofluorescence staining showed that CETP co-localized with Clec4f⁺ KCs and not Ly6C⁺ monocytes. In humans, microarray gene-expression analysis of liver biopsies revealed that hepatic expression and plasma level of CETP both correlated with hepatic VSIG4 expression. LPS administration decreased the plasma CETP concentration in humans. In vitro experiments showed that LPS reduced liver X receptor-mediated CETP expression.

CONCLUSIONS

Hepatic expression of CETP is exclusively confined to the resting KC subset (ie, F4/80⁺Clec4f⁺Vsig4⁺Ly6C^-). LPS activated resting KCs, leading to reduction of Clec4f and Vsig4 expression and reduction of hepatic CETP expression, consequently decreasing plasma CETP and raising high-density lipoprotein (HDL)-cholesterol. This sequence of events is consistent with the anti-inflammatory role of HDL in the response to LPS and may be relevant as a defense mechanism against bacterial infections.

Present therapeutic role of cholesteryl ester transfer protein inhibitors

Therapeutic interventions aimed at increasing high-density lipoprotein (HDL) levels in order to reduce the residual cardiovascular (CV) risk of optimally drug treated patients have not provided convincing results, so far. Transfer of cholesterol from extrahepatic tissues to the liver appears to be the major atheroprotective function of HDL, and an elevation of HDL levels could represent an effective strategy. Inhibition of the cholesteryl ester transfer protein (CETP), raising HDL-cholesterol (HDL-C) and apolipoprotein A-I (apoA-I) levels, reduces low-density lipoprotein-cholesterol (LDL-C) and apoB levels, thus offering a promising approach. Despite the beneficial influence on cholesterol metabolism, off-target effects and lack of reduction in CV events and mortality (with torcetrapib, dalcetrapib and evacetrapib) highlighted the complex mechanism of CETP inhibition. After the failure of the above mentioned inhibitors in phase III clinical development, possibly due to the short duration of the trials masking benefit, the secondary prevention REVEAL trial has recently shown that the inhibitor anacetrapib significantly raised HDL-C (+104%), reduced LDL-C (-18%), with a protective effect on major coronary events (RR, 0.91; 95%CI, 0.85-0.97; p = 0.004). Whether LDL-C lowering fully accounts for the CV benefit or if HDL-C-rise is a crucial factor still needs to be determined, although the reduction of non-HDL (-18%) and Lp(a) (-25%), should be also taken into account. In spite of the positive results of the REVEAL Study, Merck decided not to proceed in asking regulatory approval for anacetrapib. Dalcetrapib (Dal-GenE study) and CKD-519 remain the two molecules within this area still in clinical development.