Colchicine in atrial fibrillation: are old trees in bloom?

Colchicine is a widely used drug that was originally used to treat gout and rheumatic diseases. In recent years, colchicine has shown high potential in the cardiovascular field. Atrial fibrillation (AF) is a cardiovascular disease with a high incidence. One of the most frequent complications following cardiovascular surgery is postoperative atrial fibrillation (POAF), which affects patient health and disease burden. This article reviews the research status of colchicine in AF and summarizes the relevant progress.

Efficacy and Safety of Different Dosing Regimens of Colchicine in Patients With Coronary Artery Disease: A Network Meta-analysis of 15 Randomized Controlled Trials

ABSTRACT

Several meta-analyses have investigated the effects of different doses of colchicine in treating coronary artery disease, but all dosing regimens were never compared in a single study. We aimed to compare the efficacy and safety of 3 dosing regimens of colchicine in patients with coronary artery disease. PubMed, EMBASE, the Cochrane Library, and SCOPUS were searched for randomized controlled trials involving different colchicine doses. Major adverse cardiac events (MACE), all-cause and cardiovascular mortality, recurrent myocardial infarction (MI), stroke, gastrointestinal adverse events (AEs), discontinuation, and hospitalization were evaluated using risk ratio (RR) with 95% confidence interval (CI). A total of 15 randomized controlled trial involving 13,539 patients were included. Pooled results calculated with STATA 14.0 showed that low-dose colchicine significantly reduced MACE (RR, 0.51; 95% CI, 0.32-0.83), recurrent MI (RR, 0.56; 95% CI, 0.35-0.89), stroke (RR, 0.48; 95% CI, 0.23-1.00), and hospitalization (RR, 0.44; 95% CI, 0.22-0.85), whereas high and loading doses significantly increased gastrointestinal AEs (RR, 2.84; 95% CI, 1.26-6.24) and discontinuation (RR, 2.73; 95% CI, 1.07-6.93), respectively. Sensitivity analyses confirmed that 3 dosing regimens did not reduce all-cause and cardiovascular mortality but significantly increased the gastrointestinal AEs, and high dose significantly increased AEs-related discontinuation; loading dose resulted in more discontinuation than low dose. Although differences between 3 dosing regimens of colchicine are not significant, low dose is more effective in reducing MACE, recurrent MI, stroke, and hospitalization than the control, whereas high and loading doses increase gastrointestinal AEs and discontinuation, respectively.

Molecular Mechanisms of Inflammasome in Ischemic Stroke Pathogenesis

Ischemic stroke (also called cerebral ischemia) is one of the leading causes of death and severe disability worldwide. NLR inflammasomes play a crucial role in sensing cell damage in response to a harmful stimuli and modulating the inflammatory response, promoting the release of pro-inflammatory cytokines such as IL-18 and IL-1β following ischemic injury. Therefore, a neuroprotective effect is achieved by inhibiting the expression, assembly, and secretion of inflammasomes, thus limiting the extent of brain detriment and neurological sequelae. This review aims to illustrate the molecular characteristics, expression levels, and assembly of NLRP3 (nucleotide-binding oligomerization domain-like receptor [NLR] family pyrin-domain-containing 3) inflammasome, the most studied in the literature, in order to discover promising therapeutic implications. In addition, we provide some information regarding the contribution of NLRP1, NLRP2, and NLRC4 inflammasomes to ischemic stroke pathogenesis, highlighting potential therapeutic strategies that require further study.

Therapeutic potential of colchicine in cardiovascular medicine: a pharmacological review

Colchicine is an ancient herbal drug derived from Colchicum autumnale. It was first used to treat familial Mediterranean fever and gout. Based on its unique efficacy as an anti-inflammatory agent, colchicine has been used in the therapy of cardiovascular diseases including coronary artery disease, atherosclerosis, recurrent pericarditis, vascular restenosis, heart failure, and myocardial infarction. More recently, colchicine has also shown therapeutic efficacy in alleviating cardiovascular complications of COVID-19. COLCOT and LoDoCo2 are two milestone clinical trials that confirm the curative effect of long-term administration of colchicine in reducing the incidence of cardiovascular events in patients with coronary artery disease. There is growing interest in studying the anti-inflammatory mechanisms of colchicine. The anti-inflammatory action of colchicine is mediated mainly through inhibiting the assembly of microtubules. At the cellular level, colchicine inhibits the following: (1) endothelial cell dysfunction and inflammation; (2) smooth muscle cell proliferation and migration; (3) macrophage chemotaxis, migration, and adhesion; (4) platelet activation. At the molecular level, colchicine reduces proinflammatory cytokine release and inhibits NF-κB signaling and NLRP3 inflammasome activation. In this review, we summarize the current clinical trials with proven curative effect of colchicine in treating cardiovascular diseases. We also systematically discuss the mechanisms of colchicine action in cardiovascular therapeutics. Altogether, colchicine, a bioactive constituent from an ancient medicinal herb, exerts unique anti-inflammatory effects and prominent cardiovascular actions, and will charter a new page in cardiovascular medicine.

Efficacy and Safety of Colchicine in Prevention of Secondary Cardiovascular Outcomes Among Patients With Coronary Vessel Disease: A Meta-Analysis

Coronary vessel disease (CVD) is a class of diseases that impacts the blood vessels and heart and is one of the leading causes of disability and death. CVD includes cerebrovascular disease and coronary heart disease, both illnesses of the vessels transporting the oxygenated blood to the brain or heart. Colchicine is an inexpensive and old drug with strong anti-inflammatory effects. Numerous randomized control trials (RCTs) have demonstrated the effectiveness of low-dose colchicine for the prevention of severe cardiovascular events without showing any signs of serious adverse effects within the regime of treatment. In the current meta-analysis, we aim to assess the efficacy and safety of colchicine for secondary cardiovascular outcome prevention among patients with clinically proven CVD. The current meta-analysis was carried out using the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. PUBMED, Cochrane, and EMBASE databases were used to search for RCTs comparing colchicine and placebos for the prevention of secondary cardiovascular outcomes. The primary efficacy endpoint was mortality due to cardiovascular disease, stroke, urgent coronary revascularization, and myocardial infarction. Secondary efficacy outcomes included death due to all-cause mortality. Seven RCTs were reviewed, with a pooled sample size of 12114, out of which 6099 were randomized to the colchicine group, and 6015 were randomized to the control group. The decrease in cardiovascular events, including myocardial infarction, stroke, urgent coronary revascularization, and cardiac-related death, was significantly lower in patients randomized to colchicine (p-value<0.05). The incidence of safety outcomes did not vary significantly different between groups (p>0.05). In patients with CVD, compared to standard medical therapy, colchicine significantly decreases the risk of cardiovascular events such as cardiovascular-related death, myocardial infarction, stroke, and urgent coronary revascularizations.

Atherosclerosis: Pathogenesis and Key Cellular Processes, Current and Emerging Therapies, Key Challenges, and Future Research Directions

Atherosclerosis is the principal cause of cardiovascular disease that continues to be a substantial drain on healthcare systems, being responsible for about 31% of all global deaths. Atherogenesis is influenced by a range of factors, including oxidative stress, inflammation, hypertension, and hyperlipidemia, and is ultimately driven by the accumulation of low-density lipoprotein cholesterol within the arterial wall of medium and large arteries. Lipoprotein accumulation stimulates the infiltration of immune cells (such as monocytes/macrophages and T-lymphocytes), some of which take up the lipoprotein, leading to the formation of lipid-laden foam cells. Foam cell death results in increased accumulation of dead cells, cellular debris and extracellular cholesterol, forming a lipid-rich necrotic core. Vascular smooth muscle cells from the arterial media also migrate into the intima layer and proliferate, taking up the available lipids to become foam cells and producing extracellular matrix proteins such as collagen and elastin. Plaque progression is characterized by the formation of a fibrous cap composed of extracellular matrix proteins and smooth muscle cells, which acts to stabilize the atherosclerotic plaque. Degradation, thinning, and subsequent rupture of the fibrous cap leads to lumen-occlusive atherothrombosis, most commonly resulting in heart attack or stroke. This chapter describes the pathogenesis of atherosclerosis, current and emerging therapies, key challenges, and future directions of research.

Key Roles of Inflammation in Atherosclerosis: Mediators Involved in Orchestrating the Inflammatory Response and Its Resolution in the Disease Along with Therapeutic Avenues Targeting Inflammation

Inflammation is a critical driver of all stages of atherosclerosis, from lesion development to plaque rupture. Cytokines are mediators of the immune response and in atherosclerosis, the balance of anti- and pro-inflammatory cytokines is tipped in favor of the latter, resulting in persistent and unresolved inflammation. Although reducing plasma cholesterol levels mainly via the use of statins has positively impacted patient outcomes and reduced mortality rates, the presence of significant residual inflammation and cardiovascular risk posttherapy emphasizes the prevailing risk of primary and secondary events driven by inflammation independently of hyperlipidemia. Given the dominant role of inflammation in driving pathogenesis, alternative therapeutic avenues beyond targeting lowering of plasma lipids are required. This chapter will discuss the role of inflammation and pro-inflammatory cytokines in driving atherogenesis and disease progression, the therapeutic potential of targeting cytokines for atherosclerosis and promising avenues in this area.

NLRP3 inflammasome activation and its inhibitory drugs in connection with COVID-19 infection

SARS-CoV-2 virus belongs to the beta coronavirus family that cause the inflammatory condition, acute pneumonia, and acute respiratory distress syndrome (ARDS). ARDS is the most important reason of mortality in patients, characterized as a highly increased levels of pro-inflammatory cytokine secretion. Inflammasome is a complex, which has an essential role in inflammatory situation, and NOD, LRR- and pyrin domain-containing protein 3 (NLRP3) is the most studied inflammasome that is considered to play vital roles in the virus infection and its pathogenesis. Our search language was limited to English and the search was performed in Web of Science, PubMed and Embase. Based on published articles, our current narrative review first explains the structure of the SARS-Cov2 virus and then describes the function of the NLRP3 inflammasome in relation to COVID-19 and drugs effective in controlling it. The NLRP3 inflammasome activation related to the initiation of inflammatory cascade including important cytokines production and releases such as IL-6, TNF-α and IL-1β. Thus, targeting the NLRP3 as a member of the innate immune system may be helpful for the reduction of ARDS clinical symptoms in COVID-19 patients.

Drug delivery systems as immunomodulators for therapy of infectious disease: Relevance to COVID-19

The emergence of SARS-CoV-2, and the ensuing global pandemic, has resulted in an unprecedented response to identify therapies that can limit uncontrolled inflammation observed in patients with moderate to severe COVID-19. The immune pathology behind COVID-19 is complex and involves the activation and interaction of multiple systems including, but not limited to, complement, inflammasomes, endothelial as well as innate and adaptive immune cells to bring about a convoluted profile of inflammation, coagulation and tissue damage. To date, therapeutic approaches have focussed on inhibition of coagulation, untargeted immune suppression and/or cytokine-directed blocking agents. Regardless of recently achieved improvements in individual patient outcomes and survival rates, improved and focussed approaches targeting individual systems involved is needed to further improve prognosis and wellbeing. This review summarizes the current understanding of molecular and cellular systems involved in the pathophysiology of COVID-19, and their contribution to pathogen clearance and damage to then discuss possible therapeutic options involving immunomodulatory drug delivery systems as well as summarising the complex interplay between them.

Role of pyroptosis in atherosclerosis and its therapeutic implications

Atherosclerosis is a significant cardiovascular burden and a leading cause of death worldwide, recognized as a chronic sterile inflammatory disease. Pyroptosis is a novel proinflammatory regulated cell death, characterized by cell swelling, plasma membrane bubbling, and robust release of proinflammatory cytokines (such as interleukin IL-1β and IL-18). Mounting studies have addressed the crucial contribution of pyroptosis to atherosclerosis and clarified the candidate therapeutic agents targeting pyroptosis for atherosclerosis. Herein, we review the initial characterization of pyroptosis, the detailed mechanisms of pyroptosis, current evidence about pyroptosis and atherosclerosis, and potential therapeutic strategies that target pyroptosis in the development of atherosclerosis.

Colchicine in Patients With Acute Coronary Syndrome

Background:

Inflammation plays a crucial role in clinical manifestations and complications of acute coronary syndromes (ACS). Colchicine, a commonly used treatment for gout, has recently emerged as a novel therapeutic option in cardiovascular medicine owing to its anti-inflammatory properties. We sought to determine the potential usefulness of colchicine treatment in patients with ACS.

Methods:

This was a multicenter, randomized, double-blind, placebo-controlled trial involving 17 hospitals in Australia that provide acute cardiac care service. Eligible participants were adults (18–85 years) who presented with ACS and had evidence of coronary artery disease on coronary angiography managed with either percutaneous coronary intervention or medical therapy. Patients were assigned to receive either colchicine (0.5 mg twice daily for the first month, then 0.5 mg daily for 11 months) or placebo, in addition to standard secondary prevention pharmacotherapy, and were followed up for a minimum of 12 months. The primary outcome was a composite of all-cause mortality, ACS, ischemia-driven (unplanned) urgent revascularization, and noncardioembolic ischemic stroke in a time to event analysis.

Results:

A total of 795 patients were recruited between December 2015 and September 2018 (mean age, 59.8±10.3 years; 21% female), with 396 assigned to the colchicine group and 399 to the placebo group. Over the 12-month follow-up, there were 24 events in the colchicine group compared with 38 events in the placebo group ( P =0.09, log-rank). There was a higher rate of total death (8 versus 1; P =0.017, log-rank) and, in particular, noncardiovascular death in the colchicine group (5 versus 0; P =0.024, log-rank). The rates of reported adverse effects were not different (colchicine 23.0% versus placebo 24.3%), and they were predominantly gastrointestinal symptoms (colchicine, 23.0% versus placebo, 20.8%).

Conclusions:

The addition of colchicine to standard medical therapy did not significantly affect cardiovascular outcomes at 12 months in patients with ACS and was associated with a higher rate of mortality.

Registration:

URL: https://www.anzctr.org.au ; Unique identifier: ACTRN12615000861550.

Randomized comparison between bare-metal stent plus colchicine versus drug-eluting stent alone in prevention of clinical adverse events after percutaneous coronary intervention

The use of colchicine is associated with a significant reduction of cardiac adverse events in patients with coronary artery disease. Past small randomized trials with oral immunosuppressive or anti-inflammatory therapies have demonstrated a reduction of adverse clinical events after bare metal stent implantation. The potential role of adjunctive colchicine after bare-metal stent implantation, compared with drug-eluting stent alone, is unknown. The primary end point of the study will be to compare cost-effectiveness at 1 year of follow-up of coronary intervention with bare-metal stent implantation plus 1 mg of colchicine during 3 months versus percutaneous coronary intervention with drug-eluting stent implantation alone. ClinicalTrials.gov identifier: NCT04382443.

The hidden role of NLRP3 inflammasome in obesity-related COVID-19 exacerbations: Lessons for drug repurposing

COVID-19, the illness caused by SARS-CoV-2, has a wide-ranging clinical spectrum that, in the worst-case scenario, involves a rapid progression to severe acute respiratory syndrome and death. Epidemiological data show that obesity and diabetes are among the main risk factors associated with high morbidity and mortality. The increased susceptibility to SARS-CoV-2 infection documented in obesity-related metabolic derangements argues for initial defects in defence mechanisms, most likely due to an elevated systemic metabolic inflammation ("metaflammation"). The NLRP3 inflammasome is a master regulator of metaflammation and has a pivotal role in the pathophysiology of either obesity or diabetes. Here, we discuss the most recent findings suggesting contribution of NLRP3 inflammasome to the increase in complications in COVID-19 patients with diabesity. We also review current pharmacological strategies for COVID-19, focusing on treatments whose efficacy could be due, at least in part, to interference with the activation of the NLRP3 inflammasome. LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.

Inflammation and cardiovascular diseases: lessons from seminal clinical trials

Inflammation has been long regarded as a key contributor to atherosclerosis. Inflammatory cells and soluble mediators play critical roles throughout arterial plaque development and accordingly, targeting inflammatory pathways effectively reduces atherosclerotic burden in animal models of cardiovascular (CV) diseases. Yet, clinical translation often led to inconclusive or even contradictory results. The Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS) followed by the Colchicine Cardiovascular Outcomes Trial (COLCOT) were the first two randomized clinical trials to convincingly demonstrate the effectiveness of specific anti-inflammatory treatments in the field of CV prevention, while other phase III trials-including the Cardiovascular Inflammation Reduction Trial one using methotrexate-were futile. This manuscript reviews the main characteristics and findings of recent anti-inflammatory Phase III trials in cardiology and discusses their similarities and differences in order to get further insights into the contribution of specific inflammatory pathways on CV outcomes. CANTOS and COLCOT demonstrated efficacy of two anti-inflammatory drugs (canakinumab and colchicine, respectively) in the secondary prevention of major adverse CV events (MACE) thus providing the first confirmation of the involvement of a specific inflammatory pathway in human atherosclerotic CV disease (ASCVD). Also, they highlighted the NOD-, LRR-, and pyrin domain-containing protein 3 inflammasome-related pathway as an effective therapeutic target to blunt ASCVD. In contrast, other trials interfering with a number of inflammasome-independent pathways failed to provide benefit. Lastly, all anti-inflammatory trials underscored the importance of balancing the risk of impaired host defence with an increase in infections and the prevention of MACE in CV patients with residual inflammatory risk.

Targeted pharmacotherapy for ischemia reperfusion injury in acute myocardial infarction

INTRODUCTION

Achieving reperfusion immediately after acute myocardial infarction improves outcomes; despite this, patients remain at a high risk for mortality and morbidity at least for the first year after the event. Ischemia-reperfusion injury (IRI) has a complex pathophysiology and plays an important role in myocardial tissue injury, repair, and remodeling.

AREAS COVERED

In this review, the authors discuss the various mechanisms and their pharmacological agents currently available for reducing myocardial ischemia-reperfusion injury (IRI). They review important original investigations and trials in various clinical databases for treatments targeting IRI.

EXPERT OPINION

Encouraging results observed in many preclinical studies failed to show similar success in attenuating myocardial IRI in large-scale clinical trials. Identification of critical risk factors for IRI and targeting them individually rather than one size fits all approach should be the major focus of future research. Various newer therapies like tocilizumab, anakinra, colchicine, revacept, and therapies targeting the reperfusion injury salvage kinase pathway, survivor activating factor enhancement, mitochondrial pathways, and angiopoietin-like peptide 4 hold promise for the future.

[Kidney disease care for the elderly]

In our aging population, kidney disease management needs to take into account the frailty of the elderly. Standardized geriatric assessments can be proposed to help clinicians apprehend this dimension in their daily practice. These tools allow to better identify frail patients and offer them more personalized and harmless treatments. This article aims to focus on the kidney diseases commonly observed in elderly patients and analyze their specific nephrogeriatric care modalities. It should be noticed that all known kidney diseases can be also observed in the elderly, most often with a quite similar clinical presentation. This review is thus focused on the diseases most frequently and most specifically observed in elderly patients (except for monoclonal gammopathy associated nephropathies, out of the scope of this work), as well as the peculiarities of old age nephrological care.

Cholesterol-embolization syndrome: current perspectives

Cholesterol-embolization syndrome (CES) is a multisystemic disease with various clinical manifestations. CES is caused by embolization of cholesterol crystals (CCs) from atherosclerotic plaques located in the major arteries, and is induced mostly iatrogenically by interventional and surgical procedures; however, it may also occur spontaneously. Embolized CCs lead to both ischemic and inflammatory damage to the target organ. Therefore, anti-inflammatory agents, such as corticosteroids and cyclophosphamide, have been investigated as treatment for CES in several studies, with conflicting results. Recent research has revealed that CES is actually a kind of autoinflammatory disease in which inflammasome pathways, such as NLRP3 and IL1, are induced by CCs. These recent findings may have clinical implications such that colchicine and IL1 inhibitors, namely canakinumab, may be beneficial in the early stages of CES.

Ultramorphological analysis of plaque advancement and cholesterol crystal formation in Ldlr knockout mouse atherosclerosis

BACKGOUND AND AIMS

The low-density lipoprotein receptor-deficient (Ldlr^-/-) mouse has been utilized by cardiovascular researchers for more than two decades to study atherosclerosis. However, there has not yet been a systematic effort to document the ultrastructural changes that accompany the progression of atherosclerotic plaque in this model.

METHODS

Employing several different staining and microscopic techniques, including immunohistochemistry, as well as electron and polarized microscopy, we analyzed atherosclerotic lesion development in Ldlr^-/- mice fed an atherogenic diet over time.

RESULTS

Lipid-like deposits occurred in the subendothelial space after only one week of atherogenic diet. At two weeks, cholesterol crystals (CC) formed and increased thereafter. Lipid, CC, vascular smooth muscles cells, and collagen progressively increased over time, while after 4 weeks, relative macrophage content decreased. Accelerated accumulation of plate- and needle-shaped CC accompanied plaque core necrosis. Lastly, CC were surrounded by cholesterol microdomains, which co-localized with CC through all stages of atherosclerosis, indicating that the cholesterol microdomains may be a source of CC.

CONCLUSIONS

Here, we have documented, for the first time in a comprehensive way, atherosclerotic plaque morphology and composition from early to advanced stages in the Ldlr^-/- mouse, one of the most commonly used animal models utilized in atherosclerosis research.

Why Colchicine Should Be Considered for Secondary Prevention of Atherosclerosis: An Overview

PURPOSE

Colchicine is a widely available, inexpensive drug with a range of antiinflammatory properties that may make it suitable for the secondary prevention of atherosclerosis. This review examines how past and contemporary approaches to antiinflammatory therapy for atherosclerosis have led to a better understanding of the nature of the disease and sets out the reasons why colchicine has the potential to become a cornerstone therapy in its management.

METHODS

We performed a literature search using PubMed, the Cochrane library, and clinical trial registries to identify completed and ongoing clinical studies on colchicine in coronary artery disease, and a PubMed search to identify publications on the mechanism of action of colchicine relevant to atherosclerosis.

FINDINGS

A large body of data confirms that inflammation plays a pivotal role in atherosclerosis. The translation of this extensive knowledge into improved clinical outcomes has until recently been elusive. Findings from statin trials support the possibility that targeting inflammation may be beneficial, but this evidence has been inconclusive. Direct inhibition of atherosclerotic inflammation is being explored in current clinical trials. Targeted inhibition of interleukin 1β with canakinumab provided the proof of principle that limiting inflammation can improve outcomes in atherosclerotic vascular disease, but long-term treatment with a monoclonal antibody is unlikely to have widespread uptake. Other approaches using agents with a wider set of targets are being explored. Findings from observational studies suggest that methotrexate may reduce cardiovascular risk in patients with rheumatoid arthritis, but CIRT (Cardiovascular Inflammation Reduction Trial) demonstrated that methotrexate provided no cardiovascular benefit in patients with atherosclerotic vascular disease. Recent demonstration that cholesterol crystals trigger the NLRP3 (nucleotide oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3) inflammasome and the release of inflammatory cytokines that also drive uric acid crystal-induced inflammation indicates that the multiple actions of colchicine that make it effective in gout may be relevant to preventing inflammation and limiting inflammatory injury in atherosclerosis. The ongoing LoDoCo2 (Low Dose Colchicine2) and COLCOT (Colchicine Cardiovascular Outcomes Trial) trials and several other planned large-scale rigorous trials will determine the long-term tolerability and efficacy of low-dose colchicine for secondary prevention in patients with coronary disease.

IMPLICATION

Colchicine holds promise as an important, accessible drug that could be successfully repurposed for the secondary prevention of atherosclerotic cardiovascular disease should its tolerability and cardiovascular benefits be confirmed in ongoing clinical trials.

Lithium + Colchicine: A Potential Strategy to Reduce Pro-inflammatory Effects of Lithium Treatment

PURPOSE

Rosenblat and McIntyre (Acta Psychiatr Scand. 2015;132: 180-191) propose that immune disorders are important mediators between bipolar disorders and medical comorbidities. Rosenblat et al (Bipolar Disord. 2016;18:89-101) present a meta-analysis showing that adjunctive anti-inflammatory agents could evoke moderate antidepressant responses in bipolar disorders. We propose using the anti-inflammatory drug colchicine to improve the long-term safety and efficacy of lithium treatment for bipolar disorders.

METHODS

This report is based on searches of the PubMed and Web of Science databases.

RESULTS

Bipolar disorders are associated with significant medical comorbidities such as hypertension, overweight/obesity, diabetes mellitus, metabolic syndrome, and arteriosclerosis, accompanied by enhanced release of pro-inflammatory markers during changes in mood state. During lithium therapy, granulocyte-colony stimulating factor, CD34+ hematopoietic stem/progenitor cells, and neutrophil elastase enter the circulation with activated neutrophils to promote the extravascular migration of activated neutrophils and enhance tissue inflammation. Concurrent treatment with lithium and low-dose colchicine could facilitate the responsiveness of bipolar patients to lithium by reducing leukocyte tissue emigration, the release of neutrophil elastase, and the release of leukocyte pro-inflammatory cytokines such as IL-1β that are regulated by the NLRP3 inflammasome assembly complex.

CONCLUSIONS

Concurrent therapy with lithium and low-dose colchicine could reduce complications involving leukocyte-mediated inflammatory states in bipolar patients and promote patient acceptance and responsiveness to lithium therapy.

Frequency of Cholesterol Crystals in Culprit Coronary Artery Aspirate During Acute Myocardial Infarction and Their Relation to Inflammation and Myocardial Injury

Cholesterol crystals (CCs) have been associated with plaque rupture through mechanical injury and inflammation. This study evaluated the presence of CCs during acute myocardial infarction (AMI) and associated myocardial injury, inflammation, and arterial blood flow before and after percutaneous coronary intervention. Patients presenting with AMI (n = 286) had aspiration of culprit coronary artery obstruction. Aspirates were evaluated for crystal content, size, composition, and morphology by scanning electron microscopy, crystallography, and infrared spectroscopy. These were correlated with inflammatory biomarkers, cardiac enzymes, % coronary stenosis, and Thrombolysis in Myocardial Infarction (TIMI) blush and flow grades. Crystals were detected in 254 patients (89%) and confirmed to be cholesterol by spectroscopy. Of 286 patients 240 (84%) had CCs compacted into clusters that were large enough to be measured and analyzed. Moderate to extensive CC content was present in 172 cases (60%). Totally occluded arteries had significantly larger CC clusters than partially occluded arteries (p <0.05). Patients with CC cluster area >12,000 µm² had significantly elevated interleukin-1 beta (IL-1β) levels (p <0.01), were less likely to have TIMI blush grade of 3 (p <0.01), and more likely to have TIMI flow grade of 1 (p <0.01). Patients with recurrent AMI had smaller CC cluster area (p <0.04), lower troponin (p <0.02), and IL-1β levels (p <0.04). Women had smaller CC clusters (p <0.04). Macrophages in the aspirates were found to be attached to CCs. Coronary artery aspirates had extensive deposits of CCs during AMI. In conclusion, presence of large CC clusters was associated with increased inflammation (IL-1β), increased arterial narrowing, and diminished reflow following percutaneous coronary intervention.

Differential Effects of Lipid-lowering Drugs in Modulating Morphology of Cholesterol Particles

Treatment of dyslipidemia patients with lipid-lowering drugs leads to a significant reduction in low-density lipoproteins (LDL) level and a low to moderate level of increase in high-density lipoprotein (HDL) cholesterol in plasma. However, a possible role of these drugs in altering morphology and distribution of cholesterol particles is poorly understood. Here, we describe the in vitro evaluation of lipid-lowering drug effects in modulating morphological features of cholesterol particles using the plaque array method in combination with imaging flow cytometry. Image analyses of the cholesterol particles indicated that lovastatin, simvastatin, ezetimibe, and atorvastatin induce the formation of both globular and linear strand-shaped particles, whereas niacin, fibrates, fluvastatin, and rosuvastatin induce the formation of only globular-shaped particles. Next, purified very low-density lipoprotein (VLDL) and LDL particles incubated with these drugs showed changes in the morphology and image texture of cholesterol particles subpopulations. Furthermore, screening of 50 serum samples revealed the presence of a higher level of linear shaped HDL cholesterol particles in subjects with dyslipidemia (mean of 18.3%) compared to the age-matched normal (mean of 11.1%) samples. We also observed considerable variations in lipid-lowering drug effects on reducing linear shaped LDL and HDL cholesterol particles formation in serum samples. These findings indicate that lipid-lowering drugs, in addition to their cell-mediated hypolipidemic effects, may directly modulate morphology of cholesterol particles by a non-enzymatic mechanism of action. The outcomes of these results have potential to inform diagnosis of atherosclerosis and predict optimal lipid-lowering therapy.

Preventive Role of Tetraspanin CD9 in Systemic Inflammation of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is frequently associated with extrapulmonary complications, including cardiovascular disease, diabetes, and osteoporosis. Persistent, low-grade, systemic inflammation underlies these comorbid disorders. Tetraspanins, which have a characteristic structure spanning the membrane four times, facilitate lateral organization of molecular complexes and thereby form tetraspanin-enriched microdomains that are distinct from lipid rafts. Recent basic research has suggested a preventive role of tetraspanin CD9 in COPD. CD9-enriched microdomains negatively regulate LPS-induced receptor formation by preventing CD14 from accumulating into the rafts, and decreased CD9 in macrophages enhances inflammation in mice. Mice doubly deficient in CD9 and a related tetraspanin, CD81, show pulmonary emphysema, weight loss, and osteopenia, a phenotype akin to human COPD. A therapeutic approach to up-regulating CD9 in macrophages might improve the clinical course of patients with COPD with comorbidities.

Colchicine in cardiovascular disease: an ancient drug with modern tricks

From the dark history of being a poison and purgative, colchicine has risen to become one of the few irrefutable positives in the history of pharmacology in the management of myriad inflammatory conditions. Colchicine exerts its action through binding to tubulin, which in turn affects several cellular processes and pathways modulating the inflammatory response. Despite narrow therapeutic-toxicity window and the most common complaint of gastrointestinal upset, its list of medicinal use is expanding in recent years as we continue to unravel the mystery of this ancient remedy. In this review, we summarise the history of colchicine use, discuss its pharmacokinetics and mechanism of actions, and examine the most up-to-date evidence of colchicine in the treatment of various cardiac conditions with a focus on cardiovascular disease.

Colchicine in cardiac disease: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Colchicine has unique anti-inflammatory properties that may be beneficial in various cardiovascular conditions. This systematic review and meta-analysis of randomized controlled trials (RCTs) examines this issue.

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Database from inception to June 2014 for RCTs using colchicine in adult patients with cardiac diseases. Results were pooled using random effects.

RESULTS

15 RCTs (n = 3431 patients, median treatment 3 and follow-up 15 months) were included. All but 2 used colchicine 1 mg/day. In 5 trials, n = 1301) at risk for cardiovascular disease (coronary artery disease, acute coronary syndrome or stroke, post-angioplasty [2 RCTs], or congestive heart failure), colchicine reduced composite cardiovascular outcomes by ~60 % (risk ratio [RR] 0.44, 95 % confidence interval [CI] 0.28-0.69, p = 0.0004; I(2) = 0 %) and showed a trend towards lower all-cause mortality (RR 0.50, 95 % CI 0.23-1.08, p = 0.08; I(2) = 0 %). In pericarditis or post-cardiotomy, colchicine decreased recurrent pericarditis or post-pericardiotomy syndrome (RR 0.50, 95 % CI 0.41-0.60, p < 0.0001; I(2) = 0 %; 8 RCTs, n = 1635), and post-pericardiotomy or ablation induced atrial fibrillation (RR 0.65, 95 % CI 0.51-0.82, p = 0.0003; I(2) = 31 %; 4 RCTs, n = 1118). The most common adverse event was diarrhea. Treatment discontinuation overall and due to adverse events (RR 4.34, 95 % CI 1.70-11.07, p = 0.002; I(2) = 29 %; 7 RCTs, 83/790 [10.5 %] vs. 11/697 [1.6 %]) was higher in colchicine-assigned patients.

CONCLUSIONS

Current RCT data suggests that colchicine may reduce the composite rate of cardiovascular adverse outcomes in a range of patients with established cardiovascular disease. Furthermore, colchicine reduces rates of recurrent pericarditis, post-pericardiotomy syndrome, and peri-procedural atrial fibrillation following cardiac surgery. Further RCTs evaluating the potential of colchicine for secondary prevention of cardiovascular events would be of interest.

Colchicine Acutely Suppresses Local Cardiac Production of Inflammatory Cytokines in Patients With an Acute Coronary Syndrome

BACKGROUND

Interleukin (IL)-1β, IL-18, and downstream IL-6 are key inflammatory cytokines in the pathogenesis of coronary artery disease. Colchicine is believed to block the NLRP3 inflammasome, a cytosolic complex responsible for the production of IL-1β and IL-18. In vivo effects of colchicine on cardiac cytokine release have not been previously studied. This study aimed to (1) assess the local cardiac production of inflammatory cytokines in patients with acute coronary syndromes (ACS), stable coronary artery disease and in controls; and (2) determine whether acute administration of colchicine inhibits their production.

METHODS AND RESULTS

Forty ACS patients, 33 with stable coronary artery disease, and 10 controls, were included. ACS and stable coronary artery disease patients were randomized to oral colchicine treatment (1 mg followed by 0.5 mg 1 hour later) or no colchicine, 6 to 24 hours prior to cardiac catheterization. Blood samples from the coronary sinus, aortic root (arterial), and lower right atrium (venous) were collected and tested for IL-1β, IL-18, and IL-6 using ELISA. In ACS patients, coronary sinus levels of IL-1β, IL-18, and IL-6 were significantly higher than arterial and venous levels (P=0.017, <0.001 and <0.001, respectively). Transcoronary (coronary sinus-arterial) gradients for IL-1β, IL-18, and IL-6 were highest in ACS patients and lowest in controls (P=0.077, 0.033, and 0.014, respectively). Colchicine administration significantly reduced transcoronary gradients of all 3 cytokines in ACS patients by 40% to 88% (P=0.028, 0.032, and 0.032, for IL-1β, IL-18, and IL-6, respectively).

CONCLUSIONS

ACS patients exhibit increased local cardiac production of inflammatory cytokines. Short-term colchicine administration rapidly and significantly reduces levels of these cytokines.

Colchicine for secondary prevention of cardiovascular disease

Preliminary evidence demonstrating that adding 0.5 mg of colchicine per day to statin and antiplatelet therapy reduced the risk of acute coronary events in patients with stable coronary artery disease has raised the hope that it may prove effective for the long-term secondary prevention of cardiovascular disease. The ability of colchicine to suppress blood levels of inflammatory mediators and prevent cholesterol-crystal-induced neutrophil-mediated inflammation implicated in the progression and instability of atherosclerosis adds plausibility to this clinical observation. Early intestinal intolerance in some patients is well recognized, but clinical experience gained over more than half a century with the continuous use of colchicine for the prevention of neutrophil-mediated inflammation in patients with familial Mediterranean fever and gout indicates that low-dose long-term therapy is safe. Nonetheless, before colchicine can be recommended for the secondary prevention of cardiovascular disease, further studies are required to confirm its safety and efficacy in a broad range of patients with coronary disease, and to determine whether doses of colchicine less than 0.5 mg/day might be effective and even better tolerated. Trials exploring the role of colchicine in the treatment of patients with acute coronary syndromes would also be of special interest but may require the use of doses higher than those used for long-term secondary prevention.