Angina: contemporary diagnosis and management

Stratified medicine for acute and chronic coronary syndromes: A patient-tailored approach

The traditional approach to management of cardiovascular disease relies on grouping clinical presentations with common signs and symptoms into pre-specified disease pathways, all uniformly treated according to evidence-based guidelines ("one-size-fits-all"). The goal of precision medicine is to provide the right treatment to the right patients at the right time, combining data from time honoured sources (e.g., history, physical examination, imaging, laboratory) and those provided by multi-omics technologies. In patients with ischemic heart disease, biomarkers and intravascular assessment can be used to identify endotypes with different pathophysiology who may benefit from distinct treatments. This review discusses strategies for the application of stratified management to patients with acute and chronic coronary syndromes.

INOCA: Ischemia in non-obstructive coronary arteries

This article provides a summary of the clinical spectrum of no obstructive coronary arteries. We describe the pathologies, invasive and noninvasive assessment, and management strategies.

The clinical value of β-blockers in patients with stable angina

Stable angina, one manifestation of chronic coronary syndrome (CCS), is characterised by intermittent episodes of insufficient blood supply to the myocardium, provoking symptoms of myocardial ischaemia, particularly chest pain. These attacks usually occur during exercise or stress. Anti-ischaemic drugs are the mainstay of pharmacologic management of CCS with symptoms of angina. β-blockers reduce heart rate and myocardial contractility, thus reducing myocardial oxygen consumption. These drugs have been shown to ameliorate the frequency of anginal attacks and to improve exercise capacity in these patients. Current management guidelines include β-blockers as a first-line management option for most patients with CCS and symptoms of myocardial ischaemia, alongside dihydropyridine calcium channel blockers (CCB). The presence of comorbid angina and heart failure is a strong indication for starting with a β-blocker. β-blockers are also useful in the management of angina symptoms accompanied by a high heart rate, hypertension (with or without a renin-angiotensin-aldosterone-system [RAS] blocker or CCB), or microvascular angina (with a RAS blocker and a statin). A β-blocker is not suitable for a patient with low heart rate (<50 bpm), although use of a β-blocker may be supported by a pacemaker if the β-blocker is strongly indicated) and should be used at a low dose only in patients with low blood pressure.

Role of non-invasive coronary imaging in stable angina

Chest pain represents a symptom of significant clinical concern due to the potential for lethal etiologies. Accordingly, it is critical to ascertain the presence of stable angina through various diagnostic tests to inform subsequent therapeutic strategies. Stable angina, while potentially progressing to more severe conditions if left untreated, suffers from a paucity of research regarding its management compared to other more fatal causes of chest pain. Recent advancements in radiological imaging necessitate a re-evaluation of the array and functionality of diagnostic tests, with particular emphasis on prioritizing non-invasive methods such as electrocardiography and echocardiography. This study undertakes a comprehensive review of the literature pertaining to various diagnostic tests for stable angina. We conclude that the management of a patient presenting with chest pain encompasses a continuum of care, beginning with a detailed patient history to estimate pre-test probability and culminating in computed tomography coronary angiography. This continuum is highly individualized, taking into account patient-specific variables, disease burden, and test indications. In an era of rapid research advancement, our findings delineate the optimal sequence of initial diagnostic tests, emphasizing the role of current non-invasive imaging modalities as outlined in standard clinical guidelines.

A non-interventional cardiologist's guide to coronary chronic total occlusions

Coronary chronic total occlusions (CTO) are present in up to one-third of patients with coronary artery disease (CAD). It is thus essential for all clinical cardiologists to possess a basic awareness and understanding of CTOs, including optimal evaluation and management. While percutaneous coronary intervention (PCI) for CTO lesions has many similarities to non-CTO PCI, there are important considerations pertaining to pre-procedural evaluation, interventional techniques, procedural complications, and post-procedure management and follow-up unique to patients undergoing this highly specialized intervention. Distinct from other existing topical reviews, the current manuscript focuses on key knowledge relevant to non-interventional cardiologists.

Targeted Therapies for Microvascular Disease

Coronary microvascular dysfunction (CMD) is a common cause of ischemia but no obstructive coronary artery disease that results in an inability of the coronary microvasculature to meet myocardial oxygen demand. CMD is challenging to diagnose and manage due to a lack of mechanistic research and targeted therapy. Recent evidence suggests we can improved patient outcomes by stratifying antianginal therapies according to the diagnosis revealed by invasive assessment of the coronary microcirculation. This review article appraises the evidence for management of CMD, which includes treatment of cardiovascular risk, antianginal therapy and therapy for atherosclerosis.

The invasive investigation of INOCA in the coronary catheterization lab

Over half of all patients with angina have no angiographically demonstratable obstructive coronary disease, with a significant proportion of these patients having undiagnosed microvascular dysfunction and/or vasospastic angina. In chronic coronary syndrome, ischemia with non-obstructive coronary artery disease (INOCA) often remains undiagnosed, or uninvestigated. INOCAmay occur due to vasospastic angina and microvascular dysfunction and require invasive assessment in the coronary catheterization lab. To evaluate INOCA coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) are used to assess microvascular dysfunction before acetylcholine provocation testing for coronary spasm. This review provides an overview of the invasive investigation of INOCA in the coronary catheterization lab for patients with angina to be optimally managed.

Enhanced External Counterpulsation for the Treatment of Angina With Nonobstructive Coronary Artery Disease

Angina and nonobstructive coronary artery disease (ANOCA) is associated with poor outcomes and limited treatment options. Enhanced external counterpulsation (EECP) is a noninvasive treatment that involves applying external inflatable cuffs to the lower extremities to increase blood flow during diastole, followed by deflation during systole. Although EECP is approved for treatment in patients with refractory angina due to obstructive coronary artery disease, its effectiveness in treating patients with ANOCA with refractory angina is limited to small studies. We assessed the efficacy of EECP treatment in patients with ANOCA (defined as ≤50% stenosis in any major epicardial vessels) with refractory anginaby measuring changes in Canadian Cardiovascular Society (CCS) angina class, 6-minute walk test, Duke Activity Status Index (DASI), Seattle Angina Questionnaire 7 (SAQ7), and weekly anginal episodes pre-EECP and post-EECP treatment. A total of 101 patients with ANOCA with CCS class III/IV angina completed a full course of EECP treatment at 2 large EECP centers. In 101 patients with ANOCA the mean age (SD) of 60.6 (11.3) years and 62.4% of the cohort were women. We found significant improvements post-EECP treatment in CCS angina class (mean (SD) 3.4 (0.5) to 2.4 (2.9), p <0.001), 6-minute walk test (median 1200 (IQR 972 to 1411) to 1358 (1170 to 1600), p <0.001), DASI (mean (SD) 15.2 (11.6) to 31.5 (16.3), p <0.001), SAQ7 (mean (DS) 36.2 (24.7) to 31.5 (16.3), p <0.001), and weekly anginal episodes (mean (SD) 5.3 (3.5) to 2.4 (2.9), p <0.001). After EECP treatment, 71 patients (70.3%) had an improvement of ≥1 CCS angina class, including 33 (32.7%) patients improving by ≥2 CCS classes. In conclusion, in patients with ANOCA, EECP therapy reduces CCS angina class and improves exercise tolerance and capacity; and should be considered a part of optimal medical therapy.

Targeted Therapies for Microvascular Disease

Coronary microvascular dysfunction (CMD) is a common cause of ischemia but no obstructive coronary artery disease that results in an inability of the coronary microvasculature to meet myocardial oxygen demand. CMD is challenging to diagnose and manage due to a lack of mechanistic research and targeted therapy. Recent evidence suggests we can improved patient outcomes by stratifying antianginal therapies according to the diagnosis revealed by invasive assessment of the coronary microcirculation. This review article appraises the evidence for management of CMD, which includes treatment of cardiovascular risk, antianginal therapy and therapy for atherosclerosis.

A Study of Global Quality Scale and Reliability Scores for Chest Pain: An Instagram-Post Analysis

INTRODUCTION

Utilized in the healthcare sector, social media offers numerous benefits. However, its drawbacks encompass the variable quality of unregulated and unsupervised content. Thus, we aimed to evaluate the information in content related to chest pain found across Instagram and analyze the quality and reliability of chest pain-related content via Instagram posts.

METHODOLOGY

Instagram posts with content related to chest pain were analyzed with the help of a structured questionnaire that included the Global Quality Scale (GQS) and DISCERN score (DS). To collect Instagram posts, several distinct hashtags were employed: #chestpain, #chestpains, #angina, #anginatreatment, #heartattack, #heartattacksurvivor, #heartattackprevention.

RESULTS

A total of 262 posts were included, of which 29.7% of the total posts (n=78) contained information that describes the etiology of the disease. 27.8% of the total posts (n = 73) enclosed promotional content. Posts were found to be uploaded by doctors (18.7%), hospitals (15.6%), patients (17.9%), dieticians (11.1%), healthcare organizations (9.2%), and others (27.5%). Both Global Quality and DISCERN scores were statistically significant with a p-value of 0.001.

CONCLUSIONS

The findings of this study revealed that most of the Instagram content on chest pain posted via physicians were highly reliable and had a better global quality score. Information regarding various causes, symptoms and preventive measures on Instagram can be considered as an acceptable source for patients to surf on. A major limitation is that only English content was analyzed. In the future, the use of higher quality posts produced by healthcare professionals could potentially contribute to enhancing patient education via Instagram.

Implementation and Outcomes of an Advanced Nurse Practitioner Telephone Chest Pain Clinic Developed in Response to the COVID-19 Pandemic

Introduction

During the COVID-19 pandemic, a virtual telephone advanced nurse practitioner (ANP) led chest pain clinic was set up because face-to-face clinic visits had ceased.

Methods

This retrospective cohort analysis compared the ANP virtual chest pain clinic to the face-to-face nurse specialist-led clinic.

Results

Autonomous nursing management was significantly higher in the virtual clinic, and significantly fewer patients were referred for functional testing. Coronary arterial disease (CAD) diagnosis did not differ.

Conclusion

ANP autonomy and experience enabled continued chest pain assessment and CAD diagnosis via a virtual telephone clinic.

Material basis and integrative pharmacology of danshen decoction in the treatment of cardiovascular diseases

BACKGROUND

Cardiovascular diseases (CVDs) are among the primary and predominant threats to human health with increasing incidence. Danshen Decoction (DSD) as an adjuvant therapy can benefit CVDs patients by improving clinical efficacy.

PURPOSE

The purpose of this study was to identify the active components and potential pharmacological mechanisms of DSD by combining mass spectrometry with a network pharmacology strategy and to review the use of DSD in the treatment of CVDs.

METHOD

First, the composition of DSD was analyzed by ultrahigh-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS). Second, the network pharmacology method was used to elucidate the underlying material basis and possible pharmacological mechanism of DSD for the treatment of CVDs. Finally, clinical and experimental studies on DSD in the past ten years were retrieved from the PubMed and CNKI database, and the content of these studies was used to summarize the latest progress in DSD treatment of CVDs.

OUTCOME

A total of 35 compounds were found in DSD by manual identification from the analysis of MS, which may be the material basis for the therapeutic effect of DSD. After taking the intersection of 2086 targets related to CVDs, these 35 compounds are considered to play a role in the treatment of CVDs through 210 targets including signal transducer and activator of transcription 3 (STAT3), sarcoma (SRC) and phosphoinositide-3-kinase regulatory subunit (PIK3R), and a total of 168 signaling pathways were involved in the regulation of CVDs by DSD, including PI3K-AKT signaling pathway, Alzheimer disease, and Rap1 signaling pathway. A total of 29 clinical studies using DSD in the treatment of CVDs were included in the literature review, and these studies showed the positive significance of DSD as adjuvant therapy, while 14 experimental studies included in the literature review also demonstrated the effectiveness of DSD in the treatment of CVDs.

CONCLUSION

DSD plays a role in the treatment of CVDs through a variety of active ingredients. Large-scale clinical research and more in-depth experimental research will help to further reveal the mechanism of DSD in the treatment of CVDs.

Targeted Therapies for Microvascular Disease

Coronary microvascular dysfunction (CMD) is a common cause of ischemia but no obstructive coronary artery disease that results in an inability of the coronary microvasculature to meet myocardial oxygen demand. CMD is challenging to diagnose and manage due to a lack of mechanistic research and targeted therapy. Recent evidence suggests we can improved patient outcomes by stratifying antianginal therapies according to the diagnosis revealed by invasive assessment of the coronary microcirculation. This review article appraises the evidence for management of CMD, which includes treatment of cardiovascular risk, antianginal therapy and therapy for atherosclerosis.

Computing intracoronary blood flow rate under incomplete boundary conditions: Combing coronary anatomy and fractional flow reserve

BACKGROUND

Accurate measurement of intracoronary blood flow rate is of great significance for the diagnosis of ischemic heart disease (IHD). Computational fluid dynamic (CFD) method, combining coronary angiography images and fractional flow reserve (FFR), provides a new way to calculate the mean flow rate. However, due to the incomplete boundary conditions obtained by FFR, side branches were ignored which was likely to have a significant impact on the accuracy. In this paper, a novel CFD based method for calculating the mean intracoronary flow rate under incomplete pressure boundary conditions was proposed, in order to improve the accuracy by including the side branches.

METHODS

A pressure-flow curve based flow resistance model was employed to model resistance of the epicardial arteries. A series of steady flow simulations were performed to extract the parameters of the flow resistance model, which implicitly specified constraints for splitting flow between branches and thus enabled the mean intracoronary blood flow rate to be calculated in two or more branches under incomplete pressure boundary conditions. Simulation experiments were designed to validate the proposed method in both idealized and reconstructed 3D models of coronary branches, and the impact of the assumed coefficient of the Murray's Law for splitting flow between branches was also investigated.

RESULTS

The mean percentage error of the proposed method was +2.05%±0.04% for idealized models and +2.24%±0.01% for reconstructed models, and it was much lower than that of the method ignoring side branches (+38.48%±10.45% for idealized models and +30.54%±6.12% for reconstructed models). When the assumed coefficient of the Murray's Law was inconsistent with the real blood flow condition, the percentage errors still maintained less than about 3.00%.

CONCLUSIONS

The proposed method provided an easy and accurate way to measure the mean intracoronary flow rate and would facilitate the accurate diagnosis of IHD.

Analysis of acupoint selection and prescription rules of acupuncture for treatment of stable angina pectoris based on a Traditional Chinese Medicine inheritance calculation platform: A systematic review

The use of acupuncture to treat stable angina pectoris is increasing popularity. Based on the prevalence of this treatment over the past 20 years, the rule of acupoint selection and prescription were summarized in this study. The China National Knowledge Infrastructure, China Academic Journal Database, Chinese Science and Technology Periodical Database, PubMed and Web of Science were used for literature search clinical studies on acupuncture in the treatment of stable angina pectoris conducted over the past 20 years were identified, 225 studies were included. Prescriptions were entered into the Traditional Chinese Medicine heritage calculation platform and association rule analysis and complex entropy clustering analysis were performed. Of the sixty-seven acupoints were regularly used and PC6, BL15 and RN17 were the most common. Commonly used meridians were the foot sun bladder meridian, Renmai and hand Shaoyin pericardium meridian; Get the basic prescription of PC6, RN17 and BL15and have two new prescriptions: BL15, ST36 and GB39; DU10, DU11 and RN17. All acupoints act on the heart through neural regulation mechanism. There are many clinical practice guidelines worldwide for writing acupuncture into the recommended therapy. Acupuncture has a clear therapeutic effect on stable angina pectoris. In the treatment of stable angina pectoris, all acupoints directly or indirectly act on the heart, dredge meridians and relieve angina symptoms.

Cardiac computed tomography-derived coronary artery volume to myocardial mass

In the absence of disease impacting the coronary arteries or myocardium, there exists a linear relationship between vessel volume and myocardial mass to ensure balanced distribution of blood supply. This balance may be disturbed in diseases of either the coronary artery tree, the myocardium, or both. However, in contemporary evaluation the coronary artery anatomy and myocardium are assessed separately. Recently the coronary lumen volume to myocardial mass ratio (V/M), measured noninvasively using coronary computed tomography angiography (CTCA), has emerged as an integrated measure of myocardial blood supply and demand in vivo. This has the potential to yield new insights into diseases where this balance is altered, thus impacting clinical diagnoses and management. In this review, we outline the scientific methodology underpinning CTCA-derived measurement of V/M. We describe recent studies describing alterations in V/M across a range of cardiovascular conditions, including coronary artery disease, cardiomyopathies and coronary microvascular dysfunction. Lastly, we highlight areas of unmet research need and future directions, where V/M may further enhance our understanding of the pathophysiology of cardiovascular disease.

Diagnostik, Therapie und die Bedeutung der Lebensqualität von Patienten mit chronischem Koronarsyndrom

Hintergrund: Das Krankheitsbild der chronischen koronaren Herzkrankheit hat sich in den vergangenen Jahren erheblich gewandelt. Davon zeugt nicht zuletzt die Neudefinition der Erkrankung als chronisches Koronarsyndrom (chronic coronary syndrome, CCS) im Jahr 2019. Vor dem Hintergrund dieser Entwicklung war das primäre Ziel der Versorgungsstudie ALTHEA, einen Einblick in die aktuelle Versorgung von Patienten mit CCS und stabiler Angina pectoris (AP) in der hausärztlichen Praxis in Deutschland zu erhalten.

Methode: ALTHEA ist eine bundesweit durchgeführte Querschnittstudie unter Verwendung eines strukturierten Fragebogens bestehend aus geschlossenen Single- bzw. Multiple-Choice-Fragen. Der Fragebogen umfasste 10 Fragen zu den Bereichen Diagnostik, symptomatische Therapie und Lebensqualität von Patienten mit Verdacht auf bzw. mit diagnostiziertem CCS und stabiler AP. Die Befragung richtete sich an Hausärzte.

Ergebnisse: Die Befragung fand von April bis September 2021 statt. Angesprochen wurden bundesweit 1.050 Hausärzte, mit dem Ziel eine möglichst repräsentative Stichprobe zu erhalten. Von diesen haben 1.021 teilgenommen. Die Befragten gaben mehrheitlich an, bei Verdacht auf CCS eine apparative Diagnostik eigenständig durchzuführen, zu einem hohen Anteil einschließlich eines Belastungs-EKGs. Hinsichtlich des Therapieziels gewichtete die Mehrheit der Befragten eine Verbesserung der Lebensqualität höher als eine Prognoseverbesserung. Die überwiegende Mehrheit der befragten Hausärzte gab zudem an, bei symptomatischen Patienten mit Verdacht auf CCS eigenständig eine symptomatische Therapie einzuleiten und deren Erfolg im weiteren Krankheitsverlauf zu kontrollieren. Bei der Bewertung der verfügbaren Antianginosa zeigten sich Präferenzen in Bezug auf Wirksamkeit (Betablocker), Verträglichkeit (Ranolazin) und Einfluss auf die Lebensqualität (Ranolazin).

Schlussfolgerungen: Die Versorgungsstudie macht deutlich, dass sich Hausärzte in der gegenwärtigen Versorgung von Patienten mit Verdacht auf CCS und stabiler AP als wichtige Lotsen der Kardiologie verstehen. Sie übernehmen grundlegende Aufgaben in Diagnostik und symptomatischer Therapie, die zum Teil eine deutliche Schnittmenge mit dem Aufgabenbereich der Kardiologen bilden. Demnach zeigt die Studie bei der Versorgung dieser Patienten eine enge Verzahnung von Allgemeinmedizin und Kardiologie.

Schlüsselwörter: Angina pectoris, chronisches Koronarsyndrom, koronare Herzkrankheit, Diagnostik, symptomatische Therapie, Lebensqualität, hausärztliche Versorgung

Eingereicht am 10.1.2022 - Revision akzeptiert am 15.3.2022

Research Advances in Cardio-Cerebrovascular Diseases of Ligusticum chuanxiong Hort

Cardio-cerebrovascular diseases (CVDs) are a serious threat to human health and account for 31% of global mortality. Ligusticum chuanxiong Hort. (CX) is derived from umbellifer plants. Its rhizome, leaves, and fibrous roots are similar in composition but have different contents. It has been used in Japanese, Korean, and other traditional medicine for over 2000 years. Currently, it is mostly cultivated and has high safety and low side effects. Due to the lack of a systematic summary of the efficacy of CX in the treatment of CVDs, this article describes the material basis, molecular mechanism, and clinical efficacy of CX, as well as its combined application in the treatment of CVDs, and has been summarized from the perspective of safety. In particular, the pharmacological effect of CX in the treatment of CVDs is highlighted from the point of view of its mechanism, and the complex mechanism network has been determined to improve the understanding of CX's multi-link and multi-target therapeutic effects, including anti-inflammatory, antioxidant, and endothelial cells. This article offers a new and modern perspective on the impact of CX on CVDs.

What an Interventionalist Needs to Know About INOCA

Ischaemia with non-obstructed coronary artery disease (INOCA) remains a diagnostic and therapeutic challenge. An anatomical investigationbased approach to ischaemic heart disease fails to account for disorders of vasomotion. The main INOCA endotypes are microvascular angina, vasospastic angina, mixed (both) or non-cardiac symptoms. The interventional diagnostic procedure (IDP) enables differentiation between clinical endotypes, with linked stratified medical therapy leading to a reduced symptom burden and a better quality of life. Interventionists are therefore well placed to make a positive impact with more personalised care. Despite adjunctive tests of coronary function being supported by contemporary guidelines, IDP use in daily practice remains limited. More widespread adoption should be encouraged. This article reviews a stratified approach to INOCA, describes a streamlined approach to the IDP and highlights some practical and safety considerations.

Predicting Long-Term Mortality in Patients with Angina across the Spectrum of Dysglycemia: A Machine Learning Approach

We aimed to develop and validate a model for predicting mortality in patients with angina across the spectrum of dysglycemia. A total of 1479 patients admitted for coronary angiography due to angina were enrolled. All-cause mortality served as the primary endpoint. The models were validated with five-fold cross validation to predict long-term mortality. The features selected by least absolute shrinkage and selection operator (LASSO) were age, heart rate, plasma glucose levels at 30 min and 120 min during an oral glucose tolerance test (OGTT), the use of angiotensin II receptor blockers, the use of diuretics, and smoking history. This best performing model was built using a random survival forest with selected features. It had a good discriminative ability (Harrell’s C-index: 0.829) and acceptable calibration (Brier score: 0.08) for predicting long-term mortality. Among patients with obstructive coronary artery disease confirmed by angiography, our model outperformed the Global Registry of Acute Coronary Events discharge score for mortality prediction (Harrell’s C-index: 0.829 vs. 0.739, p < 0.001). In conclusion, we developed a machine learning model to predict long-term mortality among patients with angina. With the integration of OGTT, the model could help to identify a high risk of mortality across the spectrum of dysglycemia.

Chronic Coronary Syndromes in Women: Challenges in Diagnosis and Management

Sex matters in science. This particularly applies to ischemic heart disease, which displays key differences in pathophysiology, presentation, and effectiveness in diagnostic strategies and management between women and men. However, underrepresentation of women in randomized trials has led to an evidence gap in clinical practice. Nevertheless, it has become clear that women present with a higher burden of symptoms and comorbidities, experience worse outcomes, but are less likely to have flow-limiting stenosis in epicardial coronary arteries than men. A major contributor to this paradox is coronary microvascular disease, a heterogeneous disorder with multifactorial etiology that predominantly affects women. There is a significant interplay between coronary microvascular disease, obstructive coronary artery disease, and the cardiovascular risk associated with it, with impaired vasomotor function often preceding the development of advanced atheroma. This novel concept has recently been referred to as chronic coronary syndromes, which better meets the female phenotype of ischemic heart disease, questioning current management recommendations that still largely apply to flow-limiting stenoses in epicardial coronary arteries typically found in men. The goal of this review is to highlight the most recent scientific advances in understanding chronic coronary syndromes in women. It provides practical advice with focus on challenges in diagnosis and management, and discusses perspectives towards the implementation of sex-specific, safer, and more effective therapeutic strategies.

Metformin protects cardiomyocytes against oxygen-glucose deprivation injury by promoting autophagic flux through AMPK pathway

Metformin has been shown to protect myocardial ischaemia/reperfusion or hypoxia/reoxygenation injury. In our current study, we investigated the effects of metformin on autophagy and its possible underlying mechanisms in in vivo myocardial infarction (MI) model and in vitro oxygen-glucose deprivation (OGD) model. A rat model of MI was made by ligating coronary artery in vivo study. Metformin (200 mg/kg/day) could improve cardiac function, prevent rats from MI-induced injury by reducing myocardial infarct size and apoptosis. Moreover, metformin furtherly promoted autophagy by increasing the protein expression of LC3-II, ATG5, ATG7 and Beclin1, and by involving AMPK pathway during MI. H9c2 cells were treated with metformin (4 mM) in vitro study to assess its effects after exposure to OGD. Metformin increased cell viability and inhibited OGD-induced LDH synthesis and cell apoptosis. Furthermore, metformin increased autophagosome formations as well as expression of autophagy-related proteins, promoted autophagic flux. In addition, metformin augmented the protein level of Bcl-2 and diminished the protein levels of Bax and cleaved caspase-3. Metformin also upregulated p-AMPK expression. Nevertheless, the above-mentioned effects of metformin on H9c2 cells were remarkably eliminated by compound C (an AMPK inhibitor). In summary, we displayed that metformin protected cardiomyocytes against OGD-induced injury and apoptosis by promoting autophagic flux through the AMPK pathway.

TBL2 methylation is associated with hyper-low-density lipoprotein cholesterolemia: a case-control study

Background

HMGCR, SCAP, SREBF1, SREBF2 and TBL2 are well-known genes that are involved in the process of lipid metabolism. However, it is not known whether epigenetic changes of these genes are associated with lipid metabolism. In this study, the methylation levels of the HMGCR, SCAP, SREBF1, SREBF2 and TBL2 genes were analyzed between samples from a hyper-low-density lipoprotein cholesterolemia (hyper-LDL) group and a control group to examine the association between the methylation levels of these genes and the risk of hyper-LDL.

Methods

In this study, a case-control approach was used to explore the association between DNA methylation and hyper-LDL. The DNA methylation levels of HMGCR, SCAP, SREBF1, SREBF2 and TBL2 genes and 231 CpG sites in the promoter regions of these genes were measured in 98 hyper-LDL participants and 89 participants without hypo-LDL.

Results

Compared with participants without hyper-LDL, patients with hyper-LDL TBL2 gene had lower methylation levels (11.93 vs. 12.02, P = 0.004). The methylation haplotypes with significant abundance in the TBL2 gene are tcttttttttt (P = 0.034), ctttttttcct (P = 0.025), ctctttctttt (P = 0.040), ccttttttttt (P = 0.028), and tctttttttttttttt.

Conclusion

The study demonstrates that participants with hyper-LDL have lower methylation of TBL2. The results suggest that DNA methylation of TBL2 can decrease the risk for hyper-LDL in humans.