Vasospasm of atherosclerotic coronary arteries precipitates acute ischemic myocardial damage in myocardial infarction-prone strain of the Watanabe heritable hyperlipidemic rabbits

Comparison of clinical outcomes in patients with mixed angina and pure vasospastic angina

OBJECTIVE

This study investigated differences in clinical outcomes between mixed angina (MA) and pure vasospastic angina (PVA).

METHODS

A total of 524 vasospastic angina patients who did or did not have >50% coronary artery stenosis from January 2005 to January 2021 were divided into two groups (Group 1: PVA, N  = 399; Group 2: MA, N  = 125) and then three groups [Group 1: PVA, N  = 399; Group 2: MA without percutaneous coronary intervention (PCI), N  = 67; Group 3: MA with PCI, N  = 58] for assessment. We recorded the incidence of major adverse cardiac and cerebrovascular events (MACCE: the composite of death, myocardial infarction, nonfatal stroke or rehospitalization) during 3-year clinical follow-up.

RESULTS

Compared to the PVA group, there were significant differences in MACCE (20.8% vs. 11.8%, P  = 0.011) and rehospitalization (20.0% vs. 9.8%, P  = 0.002) in the MA group. Kaplan-Meier analysis showed that patients in the MA with PCI group had the highest cumulative incidence rate of MACCE during the 3-year follow-up (log-rank P  < 0.001).

CONCLUSION

Compared with the PVA patients, MA patients had significantly worse clinical outcomes during long-term follow-up.

Dioscin alleviates myocardial infarction injury via regulating BMP4/NOX1-mediated oxidative stress and inflammation

BACKGROUND

Dioscin, a steroidal saponin natural product, has various pharmacological activities, such as anti-inflammatory, antioxidant, lipid-lowering. However, little is known about its effects on myocardial infarction (MI) injury. Thus, the study aimed to investigate the protective effects and possible mechanisms of dioscin.

METHODS

We evaluated protective effects of Dioscin on HL-1 cells after hypoxia based on MTT and ROS in vitro. In vivo, we ligated left anterior descending (LAD) of C57BL/6 mice to establish MI model and assess serum levels of LDH, CK-MB, cTnI, SOD, MDA and CAT treated by dioscin. In addition, myocardial damages were reflected by H&E, masson and ultrastructural examination and Electrocardiograph (ECG) was detected in MI mice. And the BMP4/NOX1 pathway was measured by western blotting, immunofluorescence assay and Real-time PCR. Furthermore, to investigate cardio-protective effects of dioscin via targeting BMP4, we transfected siBMP4 into HL-1 cells in vitro and injected BMP4 siRNA though tail veins in vivo.

RESULTS

In vitro, dioscin significantly increased the viability of HL-1 cells and inhibited ROS level under hypoxia. In vivo, dioscin markedly reduced the elevation of ST segment and alleviated myocardial infarct area in mice. In terms of serology, dioscin evidently decreased LDH, CK-MB, cTnI, MDA levels, and increased SOD level. In addition, dioscin improved the pathological status of myocardial tissue and restrained the production of collagen fibers. Mechanism study proved that dioscin notablely regulated the levels of Nrf2, Keap1, HO-1, p-NF-κB, nNF-κB, TNF-α, IL-1β and IL-6 by down-regulating the protein levels of BMP4 and NOX1 against oxidative stress and inflammation. Further investigation showed that siBMP4 transfection diminished hypoxia and MI-induced oxidative and inflammation injury. The transfection decreased LDH, CK-MB and cTnI levels, improved ischemia T-wave inversion and reduced striated muscle necrosis, nucleus dissolution, collagen fibrosis and mitochondrial swelling in mice. In addition, siBMP4 decreased ROS and MDA levels, increased SOD and CAT levels and down-regulated mRNA levels of TNF-α, IL-1β and IL-6. Moreover, BMP4, NOX1 and nNF-κB protein levels were decreased and Nrf2 levels were increased by siBMP4.

CONCLUSION

Our study confirmed that dioscin showed an outstanding anti-myocardial infarction effect via regulating BMP4/NOX1-mediated oxidative stress and inflammation, which has a promising application value and development prospect against MI injury in the future.

Vasospastic Angina: A Contemporary Review of its Pathophysiology, Diagnosis and Management

Nearly 40% of patients presenting to the catheter laboratory with angina have non-obstructed coronary arteries (ANOCA), an umbrella term that encompasses distinct pathophysiological entities, such as coronary artery spasm. Coronary artery spasm leads to sudden reversible coronary flow attenuation, which clinically manifests as vasospastic angina (VSA). VSA is associated with poor quality of life and an increased risk of major adverse cardiac events. However, the pathophysiological mechanisms underlying this phenomenon are incompletely understood, which has resulted in limited therapeutic options for patients afflicted with this condition. The past decade has seen a surge in new research being conducted in the field of ANOCA and VSA. This review article provides a comprehensive summary of the underlying pathophysiological mechanisms of VSA and the current therapeutic options. We also appraise the current diagnostic approach in patients with suspected VSA.

Layered Plaque in Organic Lesions in Patients With Coronary Artery Spasm

Background

Coronary artery spasm plays a vital role in the pathogenesis of coronary plaques. We sought to investigate the plaque characteristics of co‐existing organic lesions in patients with coronary artery spasm in comparison to those without coronary artery spasm by intracoronary optical coherence tomography (OCT).

Methods and Results

We included 39 patients who presented with a symptom suspected of coronary spastic angina and had an organic lesion, defined as ≥plaque burden of 50% assessed by OCT. Coronary artery spasm was diagnosed by positive acetylcholine provocation test, or by spontaneous spasm detected during coronary angiography. A total of 51 vessels with an organic lesion were identified. Of these, coronary artery spasm was observed in 30 vessels (spasm), while not in 21 vessels (non‐spasm). Organic lesions in the spasm vessels, compared with those in the non‐spasm vessels, had a higher prevalence of layered plaque (93% versus 38%, P<0.001), macrophages (80% versus 43%, P=0.016), and intraplaque microchannels (73% versus 24%, P<0.001), and lower prevalence of macrocalcification (23% versus 62%, P=0.009) as assessed by OCT.

Conclusions

Layered plaque, macrophages, and intraplaque microchannels, were frequently observed in organic lesions in patients with coronary artery spasm. These findings suggest that coronary artery spasm induces local thrombus formation as well as active inflammatory response, therefore increasing the risk of rapid plaque progression and ischemic events in patients with coronary artery spasm.

The role of carbonic anhydrase III and autophagy in type 2 diabetes with cardio-cerebrovascular disease

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases among the elderly people. The T2DM increases the risk of cardio-cerebrovascular disease (CCD), and the main pathological change of the CCD is atherosclerosis (AS). Meanwhile, the carbonic anhydrases (CAs) are involved in the formation and progression of plaques in AS. However, the exact physiological mechanism of carbonic anhydrase III (CAIII) has not been clear yet, and there are also no correlation study between CAIII protein and T2DM with CCD. The 8-week old diabetic mice (db/db^-/- mice) and wild-type mice (wt mice) were feed by a normal diet till 32 weeks, and detected the carotid artery vascular opening angle using the method of biomechanics; The changes of cerebral cortex and myocardium were watched by the ultrastructure, and the autophagy were observed by electron microscope; The tissue structure, inflammation and cell injury were observed by Hematoxylin and eosin (HE) staining; The apoptosis of cells were observed by TUNEL staining; The protein levels of CAIII, IL-17, p53 were detected by immunohistochemical and Western Blot, and the Beclin-1, LC3, NF-κB were detected by Western Blot. All statistical analysis is performed using PRISM software. Compared with wt mice, db/db^-/- mice' carotid artery open angle increased significantly. Electron microscope results indicated that autophagy in db/db^-/- mice cerebral cortex and heart tissue decreased and intracellular organelle ultrastructure were damaged. HE staining indicated that, db/db^-/- mice' cerebral cortex and heart tissue stained lighter, inflammatory cells infiltration, cell edema were obvious, myocardial fibers were disorder, and myocardial cells showed different degrees of degeneration. Compared with wt mice, TUNEL staining showed that there was obviously increase in db/db^-/- mice cortex and heart tissue cell apoptosis. The results of immunohistochemistry and Western Blot indicated that CAIII, Beclin-1 and LC3II/I expression levels conspicuously decreased in cortex and heart tissue of db/db^-/- mice, and the expression level of IL-17, NF-κB and p53 obviously increased. The carotid artery' vascular stiffness was increased and which was probably related with formation of AS in diabetic mice. And the autophagy participated in the occurrence and development of diabetic CCD. CAIII protein might somehow be involved in the regulation of autophagy probably through affecting cell apoptosis and inflammation, but the underlying mechanism remains to be further studied.

Curcumin Conjugated Gold Nanoclusters as Perspective Therapeutics for Diabetic Cardiomyopathy

Accumulation of lipids in the myocardium contributes to the development of cardiac dysfunctions and various chronic diseases, such as diabetic cardiomyopathy (DCM). Curcumin (Cur) can relieve lipid accumulation problems, but its efficiency is limited by poor water solubility and biocompatibility. Herein, gold nanoclusters (AuNCs) were used to improve the efficiency of Cur, and the conjugates Curcumin-AuNCs (AuCur) were developed. In the treatment of high-fat-induced myocardial cell damage, we found that AuCur could effectively reduce intracellular lipid accumulation, the increase of reactive oxygen species (ROS), the increase of mitochondrial division, and the increase of apoptosis compared with Cur. AuCur decreased the expression of the peroxisome proliferator-activated receptors-α subtype (PPARα), and the therapeutic effect of AuCur was canceled when the expression of PPARα was enhanced. For the above reasons, AuCur treated the toxic effect of high lipid on cardiomyocytes by regulating PPARα, providing a new idea and method for the treatment of DCM.

Effect of Significant Coronary Artery Stenosis on Prognosis in Patients with Vasospastic Angina: A Propensity Score-Matched Analysis

Vasospastic angina (VA) is a functional disease of the coronary artery and occurs in an angiographically normal coronary artery. However, it may also occur with coronary artery stenosis. We investigated the effect of coronary artery stenosis on clinical outcomes in VA patients. Study data were obtained from a prospective multicenter registry that included patients who had symptoms of VA. Patients were classified into two groups according to presence of significant coronary artery stenosis. Among 1920 patients with VA, 189 patients were classified in the "significant stenosis" group. The one-year composite clinical events rate was significantly higher in the significant stenosis group than in the "no significant stenosis" group (5.8% vs. 1.4%, respectively; p < 0.001). Additionally, the prevalence of ACS was significantly greater in the "significant stenosis" group (4.8% vs. 0.9%, respectively; p < 0.001). After propensity score matching, the adverse effects of significant stenosis remained. In addition, significant stenosis was independently associated with a 6.67-fold increased risk of ACS in VA patients. In conclusion, significant coronary artery stenosis can increase the adverse clinical outcomes in VA patients at long-term follow-up. Clinicians should manage traditional risk factors associated with atherosclerosis and control vasospasm as well as reduce the burden of atherosclerosis.

Personalized Clinical Phenotyping through Systems Medicine and Artificial Intelligence

Personalized Medicine (PM) has shifted the traditional top-down approach to medicine based on the identification of single etiological factors to explain diseases, which was not suitable for explaining complex conditions. The concept of PM assumes several interpretations in the literature, with particular regards to Genetic and Genomic Medicine. Despite the fact that some disease-modifying genes affect disease expression and progression, many complex conditions cannot be understood through only this lens, especially when other lifestyle factors can play a crucial role (such as the environment, emotions, nutrition, etc.). Personalizing clinical phenotyping becomes a challenge when different pathophysiological mechanisms underlie the same manifestation. Brain disorders, cardiovascular and gastroenterological diseases can be paradigmatic examples. Experiences on the field of Fondazione Policlinico Gemelli in Rome (a research hospital recognized by the Italian Ministry of Health as national leader in "Personalized Medicine" and "Innovative Biomedical Technologies") could help understanding which techniques and tools are the most performing to develop potential clinical phenotypes personalization. The connection between practical experiences and scientific literature highlights how this potential can be reached towards Systems Medicine using Artificial Intelligence tools.

Coronary Plaque Characteristics and Cut-Off Stenosis for Developing Spasm in Patients with Vasospastic Angina

Coronary plaque distribution, frequency and cut-off value of percent stenosis for developing vasospasm are uncertain in patients with vasospastic angina (VA). We enrolled 2960 patients who received coronary angiography (CAG) and ergonovine provocation test prospectively in 11 university hospitals in Korea. A total of 1836 patients with VA and 867 without VA were included. Plaque and % stenosis were defined as ≥1% luminal narrowing and mean of each segmental stenosis. Overall frequency of plaque and % diameter stenosis was compared among VA-patients with index coronary spasm positive, those with index arterial spasm negative/other arterial spasm positive (INOP) and non-VA patients. Diameter stenosis associated with the spasm positivity was investigated. Overall plaque frequency and % stenosis were higher in VA patients than non-VA patients. Plaque frequency was 27.6% (243/881) in spasm positive at LAD, 16.4% (157/955) in LAD INOP and 12.6% (109/867) in non-VA with statistic difference (P < 0.001). Same trend for higher rate was observed in LCx and RCA. For % stenosis, 36.6 vs 32.4% (p = 0.010) in LAD, 36.1 vs. 28% (p < 0.001) in LCx and 35.3 vs.30.0% (p = 0.047) in RCA, respectively. Diameter stenosis of LAD with spasm positive vs. LAD INOP vs. non-VA were 38.3%, 34.0%, 32% (P = 0.002) with similar pattern in LCx and RCA. By multivariate logistic regression analysis, coronary stenosis of LAD ≥ 35% or LCx ≥35% or RCA ≥ 40% were independent predictor of developing spasm (OR 2.019, 95% CI 1.315–3.100, P = 0.001). In conclusions, spastic coronary artery had more plaque frequency, higher % stenosis than in non-spastic coronary in VA patients. The spasm related and unrelated coronary in VA patients had more plaque than in matched and unmatched coronary arteries in non-VA patients. Coronary stenosis ≥35% in LAD and LCx was an independent predictor of developing spasm.

The relationship between residual cholesterol risk and plaque characteristics in patients with acute coronary syndrome: Insights from an optical coherence tomography study

BACKGROUND AND AIMS

The impact of residual cholesterol risk (RCR) on plaque characteristics is not fully understood. The study aims to explore the relationship between RCR and plaque features in patients presenting with acute coronary syndrome (ACS).

METHODS

All ACS patients undergoing pre-intervention optical coherence tomography (OCT) with high-sensitivity C-reactive protein (hs-CRP) <2 mg/L on admission were retrospectively enrolled from January to December 2017, at Beijing Anzhen Hospital, Capital Medical University. RCR was defined as low density lipoprotein cholesterol (LDL-C) ≥1.8 mmol/L. Patients were divided into the RCR and non-RCR groups according to baseline LDL-C.

RESULTS

A total of 90 patients (94 vessels) were included, with 50 in the RCR group and 40 in the non-RCR group, respectively. Compared with the non-RCR group, patients in the RCR group were younger (54.0 ± 11.04 vs. 58.4 ± 9.59, p = 0.049) and had a higher incidence of multivessel disease (6.0% vs. 2.5%, p = 0.028). With regard to plaque characteristics, fibrous plaque (0.0% vs 12.5%, p = 0.003) was less and fibroatheroma (79.6% vs. 50.0%, p = 0.028) was more frequently seen in the RCR group. Patients in the RCR group were more prone to present with plaque rupture (24.1% vs 5.0%, p = 0.008). Cholesterol crystal (22.2% vs 12.5%, p = 0.226) and thin-cap fibroatheroma (25.9% vs. 12.5%, p = 0.109) were more common in the RCR group, though without statistical difference. Multivariate logistic regression showed that RCR (odds ratio [OR]: 7.95, p = 0.011) and smoking (OR: 4.08, p = 0.026) were independent risk factors of plaque rupture in our patients.

CONCLUSIONS

ACS patients with RCR are more likely to have atherosclerotic plaque and plaque rupture, indicating a more vulnerable plaque phenotype.

Role of mechanical stress and neutrophils in the pathogenesis of plaque erosion

Mechanical stress is a well-recognized driver of plaque rupture. Likewise, investigating the role of mechanical forces in plaque erosion has recently begun to provide some important insights, yet the knowledge is by far less advanced. The most significant example is that of shear stress, which has early been proposed as a possible driver for focal endothelial death and denudation. Recent findings using optical coherence tomography, computational sciences and mechanical models show that plaque erosion occurs most likely around atheromatous plaque throats with specific stress pattern. In parallel, we have recently shown that neutrophil-dependent inflammation promotes plaque erosion, possibly through a noxious action on ECs. Most importantly, spontaneous thrombosis - associated or not with EC denudation - can be impacted by hemodynamics, and it is now established that neutrophils promote thrombosis and platelet activation, highlighting a potential relationship between, mechanical stress, inflammation, and EC loss in the setting of coronary plaque erosion. Here, we review our current knowledge regarding the implication of both mechanical stress and neutrophils, and we discuss their implication in the promotion of plaque erosion via EC loss and thrombosis.

The impact of antiplatelet therapy on patients with vasospastic angina: A multicenter registry study of the Japanese Coronary Spasm Association

BACKGROUND

Antiplatelet therapy (APT) is generally used in patients with coronary artery disease. However, for patients with vasospastic angina (VSA), the impact of APT is not fully understood.

METHODS

In a multicenter registry study of the Japanese Coronary Spasm Association (n = 1429), patients with or without APT were compared. The primary endpoint was major adverse cardiac events (MACEs), defined as cardiac death, non-fatal myocardial infarction, unstable angina, heart failure and appropriate ICD (Implantable cardioverter defibrillator) shock. Propensity score matching and a multivariable cox proportional hazard model were used to adjust for selection bias for treatment and potential confounding factors.

RESULTS

In the whole population, 669 patients received APT, while 760 patients did not receive APT. Patients with APT had a greater prevalence of comorbidities, such as hypertension, diabetes, dyslipidemia and smoking, than those without APT. The prevalences of previous myocardial infarction, spontaneous ST changes, significant organic stenosis and medications including calcium channel blocker, nitrate, statin and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker were greater in patients with APT than those without APT. After propensity matching (n = 335 for both groups), during the median follow-up period of 32 months, the incidence rate of MACE was comparable between the patients with and without APT (P = 0.24). MACEs occurred in 5.7% of patients with APT and in 3.6% of those without APT (P = 0.20). All-cause death occurred in 0.6% of patients with APT and 1.8% of those without APT (p = 0.16).

CONCLUSION

In this multicenter registry study, anti-platelet therapy exerted no beneficial effects for VSA patients.

Dare to Compare. Development of Atherosclerotic Lesions in Human, Mouse, and Zebrafish

Cardiovascular diseases, such as atherosclerosis, are the leading cause of death worldwide. Although mice are currently the most commonly used model for atherosclerosis, zebrafish are emerging as an alternative, especially for inflammatory and lipid metabolism studies. Here, we review the history of in vivo atherosclerosis models and highlight the potential for future studies on inflammatory responses in lipid deposits in zebrafish, based on known immune reactions in humans and mice, in anticipation of new zebrafish models with more advanced atherosclerotic plaques.

The History of the WHHL Rabbit, an Animal Model of Familial Hypercholesterolemia (I) - Contribution to the Elucidation of the Pathophysiology of Human Hypercholesterolemia and Coronary Heart Disease

Animal models that closely resemble both human disease findings and their onset mechanism have contributed to the advancement of biomedical science. The Watanabe heritable hyperlipidemic (WHHL) rabbit and its advanced strains (the coronary atherosclerosis-prone and the myocardial infarction-prone WHHL rabbits) developed at Kobe University (Kobe, Japan), an animal model of human familial hypercholesterolemia, have greatly contributed to the elucidation of the pathophysiology of human lipoprotein metabolism, hypercholesterolemia, atherosclerosis, and coronary heart disease, as described below. 1) The main part of human lipoprotein metabolism has been elucidated, and the low-density lipoprotein (LDL) receptor pathway hypothesis derived from studies using fibroblasts was proven in vivo. 2) Oxidized LDL accumulates in the arterial wall, monocyte adhesion molecules are expressed on arterial endothelial cells, and monocyte-derived macrophages infiltrate the arterial intima, resulting in the formation and progression of atherosclerosis. 3) Coronary lesions differ from aortic lesions in lesion composition. 4) Factors involved in the development of atherosclerosis differ between the coronary arteries and aorta. 5) The rupture of coronary lesions requires secondary mechanical forces, such as spasm, in addition to vulnerable plaques. 6) Specific lipid molecules in the blood have been identified as markers of the progression of coronary lesions. At the end of the breeding of the WHHL rabbit family at Kobe University, this review summarizes the history of the development of the WHHL rabbit family and their contribution to biomedical science.

Curcumin‑loaded PEG‑PDLLA nanoparticles for attenuating palmitate‑induced oxidative stress and cardiomyocyte apoptosis through AMPK pathway

Curcumin (CUR) has the ability to attenuate oxidative stress in the myocardium and to protect the myocardium from lipotoxic injury owing to its lipid-reducing properties. However, the use of CUR is limited due to its hydrophobicity and instability. In this study, CUR-loaded nanoparticles (CUR NPs) were developed using an amphiphilic copolymer, monomethoxy poly (ethylene glycol)-b-poly (DL-lactide), as a vehicle material. CUR NPs with high drug loading and small size were prepared under optimized conditions. The effects of CUR NPs on palmitate-induced cardiomyocyte injury were investigated and the possible protective mechanism of CUR NPs was also examined. It was found that CUR NPs were able to control the release of CUR and to deliver CUR to H9C2 cells, and they could prevent palmitate-treated H9C2 cells from apoptosis. In addition, CUR NPs could regulate the Bax and Bcl-2 levels of palmitate-treated H9C2 cells back to their respective normal levels. A prospective mechanism for the function of CUR NPs is that they may activate the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin complex-1/p-p70 ribosomal protein S6 kinase signaling pathway, regulate the expression of downstream proteins and resist the palmitate-induced cardiomyocyte injury. Results suggest that CUR NPs can attenuate palmitate-induced oxidative stress in cardiomyocytes and protect cardiomyocytes from apoptosis through the AMPK pathway. In view of the safety and efficiency of these CUR NPs, they have potential for application in protecting the myocardium from lipotoxic injury.

Distribution of atherosclerotic lesions in various arteries of WHHLMI rabbits, an animal model of familial hypercholesterolemia

In WHHLMI rabbits, arterial lesions develop spontaneously in various arteries even with standard chow. Here, we examined the development of arterial lesions in various arteries to demonstrate standard characteristics of arterial lesions in WHHLMI rabbits. For WHHLMI rabbits at 6, 12, 20, and 30 months of age, lesion areas and areas of arterial lumen surfaces were measured using image analysis software. Histopathological sections of arterial lesions were stained with elastic van Gieson staining. Arterial lesions developed around bifurcations and expanded with aging. In the aorta, atheromatous lesions were severe in the thoracic aorta but were mild in the distal part of the abdominal aorta. Carotid artery lesions progressed in the proximal region and at bifurcations, and the histopathological features were similar to those of coronary lesions. Pulmonary artery lesions contained many foam cells. Fibrous lesions were observed in the proximal and distal areas of the renal arteries, at the bifurcation of the iliac-femoral artery and mesenteric artery, and around the anastomosis of vertebral arteries. Lesions in the celiac artery contained foam cells and/or lipid droplets within fibrous lesions. In a pair of right and left arteries, the arterial lesions tended to progress more in the right artery. Gender did not affect analysis of arterial lesions. In conclusion, the arterial lesions expanded from bifurcations, and the morphological features of the arterial lesions varied depending on the type of artery. These results serve as reference data for arterial lesions in studies using WHHLMI rabbits.

The related factors for the recovery and maintenance time of sinus rhythm in hospitalized patients with cardiopulmonary resuscitation: A single-center retrospective case-control study

No matter in or outside hospital, the success rate of cardiopulmonary resuscitation (CPR) is very low. The sign of successful CPR is the recovery of spontaneous circulation. The premise of the recovery of spontaneous circulation is the recovery and maintenance of sinus rhythm, but there is still no related research.We aim to study the factors for the recovery and maintenance time of sinus rhythm in patients with CPR.A single-center retrospective case-control study.Ethical review was obtained (ethical approval number: 20180031).The second affiliated hospital of Xi'an Jiaotong University, Xi'an Shaanxi, China.From January 2011 to December 2016, totally 344 cases met the inclusion and exclusion criteria, sinus rhythm recovered group (SR group) (n = 130 cases), sinus rhythm unrecovered group (SUR group) (n = 214 cases).The multivariate logistic regression analysis showed that red blood cell counts (OR = 1.30, 95% CI:1.04-1.63, P = .02), rescue time (OR = 0.95, 95% CI:0.94-0.97, P <.001), the usage of norepinephrine (OR = 2.14, 95% CI:1.06-4.35, P = .04) were important factor for the recovery of sinus rhythm in patients with CPR. Multivariate linear regression analysis showed that the dosage of epinephrine, the usage of naloxone and diagnosis were important factors for maintenance time of sinus rhythm after resuscitation, P <.05. The rescue time had high accuracy to predict the recovery of sinus rhythm, the area under the receiver operator characteristic (ROC) curve (AUC) was 0.84 (0.80, 0.88), sensitivity and specificity are respectively 71.54% and 93.46%.Red blood cell counts, the rescue time and the usage of norepinephrine might be important factors for the recovery of sinus rhythm, and the dosage of epinephrine, the usage of naloxone and the diagnosis might be important factors for the maintenance time of sinus rhythm in patients with CPR.

Sudden coronary death in the young: Evidence of contractile phenotype of smooth muscle cells in the culprit atherosclerotic plaque

BACKGROUND

Culprit coronary atherosclerotic plaques (APs) from young sudden cardiac death (SCD) victims are mostly non-atheromatous, i.e., consisting of proliferative smooth muscle cells (SMCs). Coronary vasospasm has been advocated to explain plaque instability in the absence of thrombosis. Our aim was to characterize the SMC phenotype in the intima and media of coronary arteries from young SCD victims.

METHODS AND RESULTS

A total of 38 coronary artery segments were studied: (a) 18 APs from young (≤40 years old) SCD patients, (b) 9 APs from old (>40 years old) SCD patients, (c) 11 non-atherosclerotic coronary arteries from young patients (≤40 years old). Markers of differentiated SMCs such as α-smooth muscle actin (α-SMA), smooth muscle myosin heavy chains (SMMHCs), and heavy-caldesmon (h-CaD), were assessed in intima and media by immunohistochemistry and quantified morphometrically. In the intima, their expression was higher in non-atherosclerotic arteries (44.37 ± 3.03% for α-SMA, 14.21 ± 2.01% for SMMHCs, 8.90 ± 1.33% for h-CaD) and APs from young SCD victims (38.95 ± 2.29% for α-SMA, 11.92 ± 1.92% for SMMHCs, 8.93 ± 1.12% for h-CaD) compared with old patients (22.01 ± 3.56% for α-SMA, 6.39 ± 0.7% for SMMHCs, 3.00 ± 0.57% for h-CaD; all P statistically significant). The media of non-atherosclerotic arteries and APs from young SCD victims exhibited strong positivity for the differentiation markers unlike that of old patients.

CONCLUSIONS

SMCs of coronary APs as well as from the underlying media from young SCD victims exhibit strong contractile phenotype. In the setting of critical stenosis, both intima and media SMC contractility might contribute to transient coronary spasm leading to myocardial ischemia and SCD.

Progression of calcific aortic valve sclerosis in WHHLMI rabbits

BACKGROUND AND AIMS

Aortic valve stenosis (AS) is the most common valvular heart disease and can be life-threatening. The pathogenesis of aortic valve calcification remains largely unknown, primarily due to the lack of an adequate animal model. The high-cholesterol diet-induced AS model in rabbits is one of the established models, but it has the significant limitation of liver dysfunction leading to low survival rates. We hypothesized that a myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbit, an animal model of familial hypercholesterolemia and atherosclerosis, is a useful animal model of AS.

METHODS

WHHLMI rabbits, aged 20 months and 30 months (n = 19), and control Japanese White rabbits (n = 4), aged 30 months, were used and evaluated by echocardiography under anesthesia. Pathological evaluation and quantitative analyses by polymerase chain reaction (PCR) were also performed.

RESULTS

The lipid profile was similar between 20 months and 30 months. Two rabbits died due to spontaneous myocardial infarction during the study. Thirty-month-old WHHLMI rabbits exhibited significantly smaller aortic valve area (0.22 ± 0.006 cm²vs. 0.12 ± 0.01 cm², p < 0.05) and higher maximal transvalvular pressure gradient (7.0 ± 0.32 vs. 9.9 ± 0.95 mmHg, p < 0.05) than 20 month-old rabbits. Macroscopic examination of excised aortic valves demonstrated thickened and degenerated valve leaflets at 30 months. Histological evaluation confirmed thickened leaflets with calcified nodules at 30 months. Real-time PCR of resected aortic valve also showed increased expression level of calcification-related molecules including osteopontin, Sox9, Bmp2, RANKL, osteoprotegerin, and Runx2 (p < 0.05 each) in 30-month-old rabbits.

CONCLUSIONS

WHHLMI rabbits may be useful models of early-stage AS in vivo.

The Coronary Artery Running Pattern is One of the Causes of Individual Differences in the Progression of Coronary Atherosclerosis in WHHLMI Rabbits, an Animal Model for Coronary Atherosclerosis

AIMS

The relationship between the coronary artery running pattern and development of coronary lesions was re-examined herein using WHHLMI rabbits, an animal model of spontaneous coronary atherosclerosis.

METHODS

The coronary artery running pattern was analyzed using an X-ray computed tomography (CT) apparatus after perfusion. Pathological sections were prepared (Victoria blue-HE staining) at 100 µm intervals from the origin of the left circumflex artery (LCX). The severity of coronary lesions was evaluated based on cross-sectional narrowing (lesion area/inner area of the internal elastic lamina).

RESULTS

In the CT analysis, the angle of the main curvature of the LCX negatively correlated with the percentage of sections with lesions and cross-sectional narrowing. The percentage of sections with lesions was significantly higher in acute angle-type LCX than in obtuse angle-type LCX. Cross-sectional narrowing was also significantly greater in acute angle-type LCX than in obtuse angle-type LCX. The percentage of fibrous lesions was high at the proximal region of LCX, whereas that of lipid-rich lesions was high at the curvature. In 24 months age group, the percentage of sections with calcification in acute angle-type LCX was about twice that in obtuse angle-type LCX.

CONCLUSIONS

Individual differences were observed in the angle of the main curvature of the LCX, which affected the occurrence and extension of atherosclerotic lesions.

Acute Coronary Syndromes: The Way Forward From Mechanisms to Precision Treatment

Well into the 21st century, we still triage acute myocardial infarction on the basis of the presence or absence of ST-segment elevation, a century-old technology. Meanwhile, we have learned a great deal about the pathophysiology and mechanisms of acute coronary syndromes (ACS) at the clinical, pathological, cellular, and molecular levels. Contemporary imaging studies have shed new light on the mechanisms of ACS. This review discusses these advances and their implications for clinical management of the ACS for the future. Plaque rupture has dominated our thinking about ACS pathophysiology for decades. However, current evidence suggests that a sole focus on plaque rupture vastly oversimplifies this complex collection of diseases and obscures other mechanisms that may mandate different management strategies. We propose segmenting coronary artery thrombosis caused by plaque rupture into cases with or without signs of concomitant inflammation. This distinction may have substantial therapeutic implications as direct anti-inflammatory interventions for atherosclerosis emerge. Coronary artery thrombosis caused by plaque erosion may be on the rise in an era of intense lipid lowering. Identification of patients with of ACS resulting from erosion may permit a less invasive approach to management than the current standard of care. We also now recognize ACS that occur without apparent epicardial coronary artery thrombus or stenosis. Such events may arise from spasm, microvascular disease, or other pathways. Emerging management strategies may likewise apply selectively to this category of ACS. We advocate this more mechanistic approach to the categorization of ACS to provide a framework for future tailoring, triage, and therapy for patients in a more personalized and precise manner.

Atheroma Susceptible to Thrombosis Exhibit Impaired Endothelial Permeability In Vivo as Assessed by Nanoparticle-Based Fluorescence Molecular Imaging

BACKGROUND

The role of local alterations in endothelial functional integrity in atherosclerosis remains incompletely understood. This study used nanoparticle-enhanced optical molecular imaging to probe in vivo mechanisms involving impaired endothelial barrier function in experimental atherothrombosis.

METHODS AND RESULTS

Atherosclerosis was induced in rabbits (n=31) using aortic balloon injury and high-cholesterol diet. Rabbits received ultrasmall superparamagnetic iron oxide nanoparticles (CLIO) derivatized with a near-infrared fluorophore (CyAm7) 24 hours before near-infrared fluorescence imaging. Rabbits were then either euthanized (n=9) or underwent a pharmacological triggering protocol to induce thrombosis (n=22). CLIO-CyAm7 nanoparticles accumulated in areas of atheroma (P<0.05 versus reference areas). On near-infrared fluorescence microscopy, CLIO-CyAm7 primarily deposited in the superficial intima within plaque macrophages, endothelial cells, and smooth muscle cells. Nanoparticle-positive areas further exhibited impaired endothelial barrier function as illuminated by Evans blue leakage. Deeper nanoparticle deposition occurred in areas of plaque neovascularization. In rabbits subject to pharmacological triggering, plaques that thrombosed exhibited significantly higher CLIO-CyAm7 accumulation compared with nonthrombosed plaques (P<0.05). In thrombosed plaques, nanoparticles accumulated preferentially at the plaque-thrombus interface. Intravascular 2-dimensional near-infrared fluorescence imaging detected nanoparticles in human coronary artery-sized atheroma in vivo (P<0.05 versus reference segments).

CONCLUSIONS

Plaques that exhibit impaired in vivo endothelial permeability in cell-rich areas are susceptible to subsequent thrombosis. Molecular imaging of nanoparticle deposition may help to identify biologically high-risk atheroma.

Morphological features of coronary plaques in WHHLMI rabbits (Oryctolagus cuniculus), an animal model for familial hypercholesterolemia

In order to examine their suitability for studies on coronary atherosclerosis, we evaluated the features of coronary atherosclerotic plaques in myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits, a spontaneous animal model for coronary atherosclerosis and myocardial infarction. Coronary segments of the hearts of 187 WHHLMI rabbits (10–29 months old) were sectioned serially and stained histopathologically and immunohistologically. Progression of coronary lesions was prominent in rabbits that had died suddenly. The degree of coronary lesions of females was higher than that of males. Various types of atherosclerotic lesions were observed in the coronary arteries, such as plaques with a large lipid core covered by a thin fibrous cap, fatty streaks, early and advanced fibroatheromas, fibrous lesions, and advanced lesions with calcium accumulation and the vasa vasorum. In rabbits that had died suddenly, the frequencies of fibroatheromas or advanced lesions were higher than those of rabbits euthanized. Matrix metalloproteinase (MMP)-positive macrophages were detected in gaps among endothelial cells at the plaque surface, beneath the fibrous cap of thin-capped fibroatheromas, and at the bottom of the intimal plaques in which the tunica media was attenuated. Immunohistological results suggest that MMP-positive macrophages are involved in the initiation, progression, and destabilization of coronary plaques, in addition to vascular remodeling, even in WHHLMI rabbits. In conclusion, coronary lesions in WHHLMI rabbits resemble human atherosclerotic lesions, and thus, the WHHLMI rabbit is a suitable animal model for studies on human coronary plaques.

Thrombus and Plaque Erosion Characterized by Optical Coherence Tomography in Patients With Vasospastic Angina

INTRODUCTION AND OBJECTIVES

Vasospastic angina (VSA) can result in endothelial damage and thrombus formation. The aim of this study was to evaluate the incidence of thrombus and plaque characteristics at coronary spasm segments compared with nonspasm segments by using optical coherence tomography (OCT) in patients with suspected VSA.

METHODS

One hundred and eighty-three patients with suspected VSA were enrolled in this study. The ergonovine provocation test was performed in all patients for the diagnosis of VSA except in patients with spontaneous spasm. All target lesions were analyzed by OCT. Plaque erosion was defined as the presence of attached thrombus overlying an intact fibrous cap and visualized plaque on multiple adjacent OCT frames.

RESULTS

One hundred and nine spasm segments (93 patients) were compared with 55 nonspasm segments (39 patients). Thrombus was more frequently seen at spasm segments than at nonspasm segments (28.4% vs 7.3%; P = .026) and thrombus size was larger at spasm segments than at nonspasm segments (0.26 ± 0.50 mm² vs 0.04 ± 0.01 mm²; P = .023). Thin-cap fibroatheroma was more frequently seen at nonspasm segments than at spasm segments (16.4% vs 1.8%; P = .006). Plaque erosion was more prevalent at spasm segments than at nonspasm segments (25.7% vs 5.4%; P = .001).

CONCLUSIONS

Thrombus and plaque erosion were more common at spasm segments than at nonspasm segments assessed by OCT in patients with suspected VSA. These findings suggest the potential benefit and treatment role of antiplatelet therapy in vasospastic angina.

High susceptibility of atherosclerotic coronary arteries to the onset of vasospasm and angina pectoris-like symptoms due to coronary spasm in WHHLMI rabbits

We examined the relationship between atherosclerosis and the provocation of coronary spasm as well as the influence of coronary spasm on the onset of acute ischemic myocardial disease. Coronary spasm was provoked in anesthetized normal Japanese white (JW) rabbits and myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits, an animal model for coronary atherosclerosis and myocardial infarction, by injecting ergonovine during the infusion of norepinephrine through a marginal ear vein. A decrease in contrast flow in the left circumflex artery was observed on coronary angiograms. Ischemic changes were observed on the electrocardiograms of 29% (2/7) of JW and 79% (27/34, P=0.007) of WHHLMI rabbits. The frequency of coronary spasm was significantly high in rabbits with severe coronary plaques showing diffuse lesions. Left ventricle motility in vasospasm-positive rabbits, which was evaluated with echocardiograms, was decreased by 29% following the ergonovine injection (P<0.001), and every serum ischemic marker markedly increased 4 h after the provocation of vasospasm. These results demonstrate that atherosclerotic coronary arteries are positively related to the provocation of vasospasm, and vasospasm in severe atherosclerotic coronary segments evokes angina pectoris-like findings and/or non-fatal myocardial infarction. WHHLMI rabbits may be a novel animal model for angina pectoris and acute ischemic heart disease.

Angiotensin II Destabilizes Coronary Plaques in Watanabe Heritable Hyperlipidemic Rabbits

OBJECTIVE

Increased plasma concentrations of angiotensin II (Ang II) have been implicated in many cardiovascular diseases, such as atherosclerosis, aortic aneurysms, and myocardial infarction, in humans. However, it is not known whether high levels of plasma Ang II affect coronary plaque stability and subsequent myocardial infarction. This study was designed to examine whether elevated plasma Ang II can directly induce coronary events, such as acute coronary syndrome.

APPROACH AND RESULTS

To examine the above hypothesis, we infused Ang II (100 ng/min per kg [low group] and 200 ng/min per kg [high group]) or saline vehicle via osmotic minipumps into Watanabe heritable hyperlipidemic rabbits, a model of human familial hypercholesterolemia and atherosclerosis. Infusion of Ang II resulted in mortality rates of 50% and 92% in the low- and high-Ang II groups, respectively, whereas there were no deaths in the vehicle group. Pathological analysis revealed that Ang II-infused Watanabe heritable hyperlipidemic rabbits that died showed myocardial infarction. Furthermore, Ang II-infused Watanabe heritable hyperlipidemic rabbits exhibited coronary plaque erosion and rupture that were associated with thrombosis.

CONCLUSIONS

These findings suggest that increased blood levels of Ang II can destabilize coronary plaques and trigger the thrombosis, which possibly induces myocardial infarction. The model described in this study provides a novel means for the study of human acute coronary syndrome.

Inflammation and plaque vulnerability

Atherosclerosis is a maladaptive, nonresolving chronic inflammatory disease that occurs at sites of blood flow disturbance. The disease usually remains silent until a breakdown of integrity at the arterial surface triggers the formation of a thrombus. By occluding the lumen, the thrombus or emboli detaching from it elicits ischaemic symptoms that may be life-threatening. Two types of surface damage can cause atherothrombosis: plaque rupture and endothelial erosion. Plaque rupture is thought to be caused by loss of mechanical stability, often due to reduced tensile strength of the collagen cap surrounding the plaque. Therefore, plaques with reduced collagen content are thought to be more vulnerable than those with a thick collagen cap. Endothelial erosion, on the other hand, may occur after injurious insults to the endothelium instigated by metabolic disturbance or immune insults. This review discusses the molecular mechanisms involved in plaque vulnerability and the development of atherothrombosis.

OCT-Defined Morphological Characteristics of Coronary Artery Spasm Sites in Vasospastic Angina

OBJECTIVES

The aim of this study was to define the morphological features of coronary artery spasm sites using optical coherence tomography (OCT) in patients with vasospastic angina (VSA).

BACKGROUND

Plaque characteristics at coronary artery spasm sites have not been investigated systematically.

METHODS

Sixty-nine consecutive patients (80 spasm sites) presenting with VSA who underwent OCT imaging were included in this study. Fibrous cap disruption was identified by the discontinuation of fibrous cap with or without intraplaque cavity formation. OCT-defined erosion was established by the presence of thrombus with or without lumen irregularity overlying an intact fibrous cap on multiple adjacent OCT frames. Other morphological features such as the absence of thrombus with or without lumen irregularity and those not in the previously mentioned criteria were also documented.

RESULTS

Plaque was seen on OCT in 79 of the 80 spasm sites. Fibrous cap disruption was detected at 3 sites (4%). OCT-defined erosion was observed at 21 spasm sites (26%). Thrombus with lumen irregularity was observed in 20 sites, whereas 1 site had thrombus without lumen irregularity. Lumen irregularity without thrombus was observed at 49 spasm sites (61%). Spontaneous spasm was seen more frequently in patients with acute myocardial infarction and out-of-hospital cardiac arrest than in patients without these conditions (50.0% vs. 19.3%, p = 0.025).

CONCLUSIONS

Our results show that OCT-defined erosion at spasm sites occurred in more than one-fourth of patients in this study. Luminal irregularity was observed in nearly two-thirds of the patients without overlying thrombus. These findings suggest the potential role of antiplatelet therapy in VSA.