Soluble CD40 ligand promotes macrophage foam cell formation in the etiology of atherosclerosis

Co-stimulators CD40-CD40L, a potential immune-therapy target for atherosclerosis: A review

The interaction between CD40 and CD40 ligand (CD40L) a crucial co-stimulatory signal for activating adaptive immune cells, has a noteworthy role in atherosclerosis. It is well-known that atherosclerosis is linked to immune inflammation in blood vessels. In atherosclerotic lesions, there is a multitude of proinflammatory cytokines, adhesion molecules, and collagen, as well as smooth muscle cells, macrophages, and T lymphocytes, particularly the binding of CD40 and CD40L. Therefore, research on inhibiting the CD40-CD40L system to prevent atherosclerosis has been ongoing for more than 30 years. However, it's essential to note that long-term direct suppression of CD40 or CD40L could potentially result in immunosuppression, emphasizing the critical role of the CD40-CD40L system in atherosclerosis. Thus, specifically targeting the CD40-CD40L interaction on particular cell types or their downstream signaling pathways may be a robust strategy for mitigating atherosclerosis, reducing potential side effects. This review aims to summarize the potential utility of the CD40-CD40L system as a viable therapeutic target for atherosclerosis.

Platelet activation: a promoter for psoriasis and its comorbidity, cardiovascular disease

Psoriasis is a chronic inflammatory skin disease with a prevalence of 0.14% to 1.99%. The underlying pathology is mainly driven by the abnormal immune responses including activation of Th1, Th17, Th22 cells and secretion of cytokines. Patients with psoriasis are more likely to develop cardiovascular disease (CVD) which has been well recognized as a comorbidity of psoriasis. As mediators of hemostasis and thromboinflammation, platelets play an important part in CVD. However, less is known about their pathophysiological contribution to psoriasis and psoriasis-associated CVD. A comprehensive understanding of the role of platelet activation in psoriasis might pave the path for more accurate prediction of cardiovascular (CV) risk and provide new strategies for psoriasis management, which alleviates the increased CV burden associated with psoriasis. Here we review the available evidence about the biomarkers and mechanisms of platelet activation in psoriasis and the role of platelet activation in intriguing the common comorbidity, CVD. We further discussed the implications and efficacy of antiplatelet therapies in the treatment of psoriasis and prevention of psoriasis-associated CVD.

Biomarkers to monitor the prognosis, disease severity, and treatment efficacy in coronary artery disease

INTRODUCTION

Coronary Artery Disease (CAD) is a prevalent condition characterized by the presence of atherosclerotic plaques in the coronary arteries of the heart. The global burden of CAD has increased significantly over the years, resulting in millions of deaths annually and making it the leading health-care expenditure and cause of mortality in developed countries. The lack of cost-effective strategies for monitoring the prognosis of CAD warrants a pressing need for accurate and efficient markers to assess disease severity and progression for both reducing health-care costs and improving patient outcomes.

AREA COVERED

To effectively monitor CAD, prognostic biomarkers and imaging techniques play a vital role in risk-stratified patients during acute treatment and over time. However, with over 1,000 potential markers of interest, it is crucial to identify the key markers with substantial utility in monitoring CAD progression and evaluating therapeutic interventions. This review focuses on identifying and highlighting the most relevant markers for monitoring CAD prognosis and disease severity. We searched for relevant literature using PubMed and Google Scholar.

EXPERT OPINION

By utilizing the markers discussed, health-care providers can improve patient care, optimize treatment plans, and ultimately reduce health-care costs associated with CAD management.

Advances in immunotherapy modalities for atherosclerosis

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. Atherosclerosis is the pathological basis of atherosclerotic cardiovascular disease (ASCVD). Atherosclerosis is now understood to be a long-term immune-mediated inflammatory condition brought on by a complicated chain of factors, including endothelial dysfunction, lipid deposits in the artery wall, and monocyte-derived macrophage infiltration, in which both innate immunity and adaptive immunity play an indispensable role. Recent studies have shown that atherosclerosis can be alleviated by inducing a protective immune response through certain auto-antigens or exogenous antigens. Some clinical trials have also demonstrated that atherosclerotic is associated with the presence of immune cells and immune factors in the body. Therefore, immunotherapy is expected to be a new preventive and curative measure for atherosclerosis. In this review, we provide a summary overview of recent progress in the research of immune mechanisms of atherosclerosis and targeted therapeutic pathways.

Correlation between Insulin Resistance with Soluble CD40 Ligand and Plasminogen Activator Inhibitor-1 Plasma in Pre-diabetic Patients

BACKGROUND: The main condition of pre-diabetes is insulin resistance that can lead to a prothrombotic state. AIM: This study aims to correlate insulin resistance with soluble CD40 ligand (sCD40L) and plasminogen activator inhibitor-1 (PAI-1) plasma in pre-diabetic patients. METHODS: This study is an analytic observational study with a cross-sectional approach. HOMA-IR assessed insulin resistance, and prothrombotic factors were assessed by PAI-1 and soluble CD40L. PAI-1 and sCD40L were examined by ELISA. These indicators were assessed on 30 pre-diabetic patients. RESULTS: Thirty subjects included in this study with a mean age of 31.47 (5.03) years old, consist of 19 (63%) men and 11 (37%) women. The mean HOMA-IR was 3.69 (1.12), PAI-1 was 10.25 (3.72) ng/mL, and the PAI-1 levels were increased (>8.4 ng/mL) in 70% of the subjects. The mean of sCD40L levels was 4495.7 (1136.3) pg/ml, and sCD40L levels were increased (>4000 pg/ml) in 63% of subject. There was a significant correlation between HOMA-IR levels and sCD40L (r = 0.636, p < 0.05) and between of HOMA-IR and PAI-1 (r = 0.742, p < 0.05). Moderate correlation was found between sCD40L levels and plasma PAI-1 (r = 0.592, p < 0.05) in pre-diabetic patient. The correlation between three variables was HOMA-IR had a significant effect on PAI-1 levels through sCD40L (t = 2.010, p < 0.05, structure loading factor = 0.286). CONCLUSION: Insulin resistance has a strong and significant correlation with sCD40L and PAI-1 levels in pre-diabetic patients.

Immune Checkpoint Therapies and Atherosclerosis: Mechanisms and Clinical Implications: JACC State-of-the-Art Review

Immune checkpoint inhibitor therapy has revolutionized the treatment of advanced malignancies in recent years. Numerous reports have detailed the myriad of possible adverse inflammatory effects of immune checkpoint therapies, including within the cardiovascular system. However, these reports have been largely limited to myocarditis. The critical role of inflammation and adaptive immunity in atherosclerosis has been well characterized in preclinical studies, and several emerging clinical studies indicate a potential role of immune checkpoint targeting therapies in the development and exacerbation of atherosclerosis. In this review, we provide an overview of the role of T-cell immunity in atherogenesis and describe the molecular effects and clinical associations of both approved and investigational immune checkpoint therapy on atherosclerosis. We also highlight the role of cholesterol metabolism in oncogenesis and discuss the implications of these associations on future treatment and monitoring of atherosclerotic cardiovascular disease in the oncologic population receiving immune checkpoint therapy.

NOS1-mediated macrophage and endothelial cell interaction in the progression of atherosclerosis

Atherosclerosis is a chronic inflammatory disease arising due to an imbalance in lipid metabolism and maladaptive immune response driven by the accumulation of cholesterol-laden macrophages in the artery wall. Interactions between monocytes/macrophages and endothelial cells play an essential role in the pathogenesis of atherosclerosis. In our current study, nitric oxide synthase 1 (NOS1)-derived nitric oxide (NO) has been identified as a regulator of macrophage and endothelial cell interaction. Oxidized LDL (OxLDL) activates NOS1, which results in the expression of CD40 ligand in macrophages. OxLDL-stimulated macrophages produce some soluble factors which increase the CD40 receptor expression in endothelial cells. This increases the interaction between the macrophages and endothelial cells, which leads to an increase in the inflammatory response. Inhibition of NOS1-derived NO might serve as an effective strategy to reduce foam cell formation and limit the extent of atherosclerotic plaque expansion.

Differential Responsiveness of the Platelet Biomarkers, Systemic CD40 Ligand, CD62P, and Platelet-Derived Growth Factor-BB, to Virally-Suppressive Antiretroviral Therapy

Systemic biomarkers of inflammation, including cytokines and chemokines, are potentially useful in the management of both HIV infection and non-AIDS-defining disorders. However, relatively little is known about the utility of measurement of circulating biomarkers of platelet activation as a strategy to monitor the efficacy of combination antiretroviral therapy (cART), as well as the persistence of systemic inflammation following virally-suppressive therapy in HIV-infected persons. These issues have been addressed in the current study to which a cohort consisting of 199 HIV-infected participants was recruited, 100 of whom were cART-naïve and the remainder cART-treated and virally-suppressed. Fifteen healthy control participants were included for comparison. The study focused on the effects of cART on the responsiveness of three biomarkers of platelet activation, specifically soluble CD40 ligand (sCD40L), sCD62P (P-selectin), and platelet-derived growth factor-BB (PDGF-BB), measured using multiplex suspension bead array technology. Most prominently sCD40L in particular, as well as sCD62P, were significantly elevated in the cART-naïve group relative to both the cART-treated and healthy control groups. However, levels of PDGF-BB were of comparable magnitude in both the cART-naïve and -treated groups, and significantly higher than those of the control group. Although remaining somewhat higher in the virally-suppressed group relative to healthy control participants, these findings identify sCD40L, in particular, as a potential biomarker of successful cART, while PDGF-BB may be indicative of persistent low-level antigenemia.

CD40/CD40L and Related Signaling Pathways in Cardiovascular Health and Disease-The Pros and Cons for Cardioprotection

The CD40-CD40 ligand (CD40L) dyad represents a scientific and clinical field that has raised many controversies in the past and cannot be clearly defined as being an either beneficial or harmful pathway. Being crucially involved in physiological immunological processes as well as pathological inflammatory reactions, the signaling pathway has been recognized as a key player in the development of both autoimmune and cardiovascular disease. Even though the possibilities of a therapeutic approach to the dyad were recognized decades ago, due to unfortunate events, detailed in this review, pharmacological treatment targeting the dyad, especially in patients suffering from atherosclerosis, is not available. Despite the recent advances in the treatment of classical cardiovascular risk factors, such as arterial hypertension and diabetes mellitus, the treatment of the associated low-grade inflammation that accounts for the progression of atherosclerosis is still challenging. Low-grade inflammation can be detected in a significant portion of patients that suffer from cardiovascular disease and it is therefore imperative to develop new therapeutic strategies in order to combat this driver of atherosclerosis. Of note, established cardiovascular drugs such as angiotensin-converting enzyme inhibitors or statins have proven beneficial cardiovascular effects that are also related to their pleiotropic immunomodulatory properties. In this review, we will discuss the setbacks encountered as well as new avenues discovered on the path to a different, inflammation-centered approach for the treatment of cardiovascular disease with the CD40-CD40L axis as a central therapeutic target.

Besieging the Tumoral Sites: Could It Be an Alternative Therapeutic Strategy in Ductal Pancreatic Adenocarcinoma?

Pancreatic ductal adenocarcinoma is characterized by its high morbidity, and curative drugs are still lacking. In addition to immunotherapy, other molecular targeted therapeutics, such as stroma depleting agents, have been evaluated, given the abundant desmoplastic stroma that is considered a protective shield for tumor cells. However, the unexpected poor outcome has raised the debate on whether desmoplasia promotes or restrains tumor cell spread. After reviewing these key points in this paper, an approach taking advantage of desmoplasia and immune cells to besiege the tumoral sites will be proposed. Based on the available literature, the feasibility and potential limitations of this strategy will be discussed.

The CD40-CD40L Dyad as Immunotherapeutic Target in Cardiovascular Disease

Chronic inflammation drives the development of atherosclerosis. Despite optimal treatment of classical cardiovascular risk factors, a substantial portion of the population has elevated inflammatory biomarkers and develops atherosclerosis-related complications, indicating that a residual inflammatory risk drives atherosclerotic cardiovascular disease in these patients. Additional anti-inflammatory therapeutic strategies are therefore required. The co-stimulatory molecule CD40 and its ligand CD40L (CD154) have a central role in the regulation of the inflammatory response during the development of atherosclerosis by modulating the interaction between immune cells and between immune cells and non-immune cells. In this review, we discuss the role of the CD40-CD40L dyad in atherosclerosis, and we discuss recent studies on the therapeutic potential of novel CD40-CD40L targeting strategies in cardiovascular medicine.

Tumour necrosis factor superfamily members in ischaemic vascular diseases

Current treatment of ischaemic vascular diseases such as coronary and peripheral artery disease includes angioplasty and bypass grafting, as well as lipid lowering therapies and control of other cardiovascular risk factors. Numerous members of the tumour necrosis factor superfamily (TNFSF) have recently shown emerging roles in both the protection and progression of such diseases. Understanding the role TNFSF members play in ischaemic vascular disease may provide insight into the development of novel therapeutics to prevent or treat diseases relating to atherosclerosis and ischaemia. This review summarizes the most recent findings relating to TNFSF members and the mechanisms that precede ischaemic vascular disease progression, particularly endothelial dysfunction, chronic inflammation, and atherosclerotic plaque development. This review also explores recent translational research on the role of TNFSF therapies in cardiovascular disease.

Inflammatory Biomarkers for Cardiovascular Risk Stratification in Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is a frequent autosomal genetic disease characterized by elevated concentrations of low-density lipoprotein cholesterol (LDL) from birth with increased risk of premature atherosclerotic complications. Accumulating evidence has shown enhanced inflammation in patients with FH. In vessels, the deposition of modified cholesterol lipoproteins triggers local inflammation. Then, inflammation facilitates fatty streak formation by activating the endothelium to produce chemokines and adhesion molecules. This process eventually results in the uptake of vascular oxidized LDL (OxLDL) by scavenger receptors in monocyte-derived macrophages and formation of foam cells. Further leukocyte recruitment into the sub-endothelial space leads to plaque progression and activation of smooth muscle cells proliferation. Several inflammatory biomarkers have been reported in this setting which can be directly synthetized by activated inflammatory/vascular cells or can be indirectly produced by organs other than vessels, e.g., liver. Of note, inflammation is boosted in FH patients. Inflammatory biomarkers might improve the risk stratification for coronary heart disease and predict atherosclerotic events in FH patients. This review aims at summarizing the current knowledge about the role of inflammation in FH and the potential application of inflammatory biomarkers for cardiovascular risk estimation in these patients.

Altered CD4+ T cell immunity in nurses occupationally exposed to viral pathogens

Pathogen exposure, including but not limited to herpesviruses, moulds the shape of the immune system, both at a basal state and in response to immune challenge. However, little is known about the impact of high exposure to other viruses on baseline immune signatures and how the immune system copes with repetitive exposures to maintain a balanced functionality. Here we investigated baseline immune signatures, including detailed T cell phenotyping, antigen-specific CD4⁺ and CD8⁺ T cell responses and cytokine profile in paediatric (PED) nurses, who have high occupational exposure to viral pathogens including varicella zoster virus (VZV) and respiratory viruses, and in neonatal intensive care unit (NICU) nurses, as a control group with infrequent occupational exposure. Our results show a lower CD4⁺ T cell response to two VZV proteins (IE62 and gE) and to tetanus toxoid (TT) in PED nurses who are cytomegalovirus (CMV)-seronegative, compared to CMV-seronegative NICU nurses, and that the decline might be more pronounced the more sustained the exposure. This decline might be due to an attrition of VZV- and TT-specific T cells as a result of the continuous pressure on the CD4⁺ T cell compartment. Moreover, our data suggest that the distinct T cell phenotypes known to be associated with CMV-seropositivity might be less prominent in PED nurses compared to NICU nurses, implying a plausible attenuating effect of occupational exposure on CMV-associated immunosenescence. Overall, this pilot study reveals an impact of occupational exposure to viral pathogens on CD4⁺ T cell immunity and supports further investigation in a larger cohort.

Beneficial impacts of regular exercise on platelet function in sedentary older adults: evidence from a randomized 6-mo walking trial

Platelet activation, including the formation of monocyte platelet aggregates (MPAs), contributes to atherosclerosis, thrombus formation, and acute coronary syndromes. Regular participation in exercise can lower cardiovascular risk, but little is known regarding the impact of exercise training on platelet function. We investigated the effect of 6 mo of walking exercise on platelet function in sedentary older adults without significant cardiovascular disease. Twenty-seven participants were randomly allocated to 6 mo of either: no-exercise ( n = 13) or 3 × 50 min/wk of supervised center-based walking ( n = 14). Circulating and agonist-induced MPAs were assessed using flow cytometry before [ month 0 (0M)] and after [ month 6 (6M)] the intervention. Circulating MPAs increased from 0M (3.7 ± 1.0%) to 6M (4.7 ± 1.6%) in the no-exercise group ( P = 0.009), whereas a nonsignificant decrease was observed in the walking group (0M 4.3 ± 1.7 vs. 6M 3.7 ± 1.2 %, P = 0.052). The change in MPAs between groups was significant ( P = 0.001). There were no differences between groups in platelet responses to agonists across the interventions (all P > 0.05). Collectively, these data suggest that the absence of regular exercise may increase MPAs, which are cellular mediators involved in atherosclerosis, while regular walking inhibits such increases. The thrombotic function of platelets appears to be relatively unaltered by exercise training. This study provides novel data related to the cardioprotective effects associated with participation in exercise. NEW & NOTEWORTHY Monocyte-platelet aggregates contribute to atherosclerosis and exercise can lower cardiovascular risk. This is the first study to discover that a lack of regular physical activity is associated with increased monocyte-platelet aggregates over a 6-mo intervention period. In contrast, walking exercise inhibits increased monocyte-platelet aggregates in the circulation. This study highlights a novel pathway by which regular participation in exercise exerts its cardioprotective effects.

Inflammatory Milieu and Cardiovascular Homeostasis in Children With Obstructive Sleep Apnea

Introduction

Biomarkers of atherosclerosis (pro-inflammatory cytokines and acute phase reactants) are elevated in children with obstructive sleep apnea (OSA). However, their association with cardiovascular endpoints in children are not understood. We hypothesized that biomarkers of atherosclerosis in children with OSA correlate with pulse transit time (PTT), a surrogate measure of vascular stiffness, with some positively influencing and others negatively influencing PTT.

Methods

Children with OSA and matched controls were recruited to the study. Pro-inflammatory cytokines and acute phase reactants were measured at 6:00 pm and 6:00 am. Polysomnography with beat-to-beat blood pressure was performed. PTT during wakefulness and stage 2 sleep was calculated. Diurnal variation of biomarkers and their associations with PTT was estimated. Factor analysis was used to determine the effect of groups of cytokines on PTT.

Results

One hundred fifty-five children participated in the study; 90 were healthy controls and 65 had OSA. Children with OSA exhibited a different diurnal variation of biomarkers than healthy controls, with pro-inflammatory cytokines peaking in the morning and acute phase reactants peaking in the afternoon. Structural equation modeling demonstrated that interleukins 6 and 8, tumor necrosis factor-α, and sCD40L had a shortening effect, while serum amyloid A, C-reactive protein, and adiponectin had a prolonging effect on PTT. As a result, there was no difference in PTT between the two groups.

Conclusion

The differential relationships of acute phase reactants and pro-inflammatory cytokines with PTT suggest that in children with OSA, these mediators may have opposing actions to maintain cardiovascular homeostasis.

Increased Levels of Oxidative Stress Markers, Soluble CD40 Ligand, and Carotid Intima-Media Thickness Reflect Acceleration of Atherosclerosis in Male Patients with Ankylosing Spondylitis in Active Phase and without the Classical Cardiovascular Risk Factors

Objective

The primary aim of the study was to assess levels of oxidative stress markers, soluble CD40 ligand (sCD40L), serum pregnancy-associated plasma protein-A (PAPP-A), and placental growth factor (PlGF) as well as carotid intima-media thickness (IMT) in patients with ankylosing spondylitis (AS) with active phase without concomitant classical cardiovascular risk factors.

Material and methods

The observational study involved 96 male subjects: 48 AS patients and 48 healthy ones, who did not differ significantly regarding age, BMI, comorbid disorders, and distribution of classical cardiovascular risk factors. In both groups, we estimated levels of oxidative stress markers, lipid profile, and inflammation parameters as well as sCD40L, serum PAPP-A, and PlGF. In addition, we estimated carotid IMT in each subject.

Results

The study showed that markers of oxidative stress, lipid profile, and inflammation, as well as sCD40L, PlGF, and IMT, were significantly higher in the AS group compared to the healthy group.

Conclusion

Our results demonstrate that ankylosing spondylitis may be associated with increased risk for atherosclerosis.

Relationship between monocyte-platelet aggregation and endothelial function in middle-aged and elderly adults

Low-grade inflammation, endothelial dysfunction, and platelet hyper-reactivity to agonists are associated with an increased risk of cardiovascular events. In vitro and animal studies infer an inverse mechanistic relationship between platelet activation and the production of endothelium-derived nitric oxide and prostacyclin. This concept is supported by evidence of an inverse relationship between endothelial function and platelet activation in high-risk cardiac patients. The aim of this study was to investigate what relationship, if any, exists between platelet and endothelial function in healthy, middle-aged, and elderly adults. In 51 participants (18 male, 33 post menopausal female), endothelial function was assessed by flow-mediated dilation (FMD). Platelet function was assessed by flow cytometric determination of glycoprotein IIb/IIIa activation (measured by PAC-1 binding), granule exocytosis (measured by surface P-selectin expression), and monocyte-platelet aggregates (MPAs), with and without stimulation by canonical platelet agonists adenosine diphosphate (ADP), arachidonic acid (AA), and collagen. Correlation analysis indicated there was no significant (all P => 0.05) relationship between FMD and any marker of in vivo platelet activation (MPAs R = 0.193, PAC-1 R = -0.113, anti-CD62P R = -0.078) or inducible platelet activation by ADP (MPA R = -0.128, anti-CD62P R = -0.237), AA (MPA R = -0.122, PAC-1 R = -0.045, anti-CD62P R = -0.142), or collagen (MPA R = 0.136, PAC-1 R = 0.174, anti-CD62P R = -0.077). Our findings contrast with two previous studies performed in high-risk cardiac patients, which reported inverse relationships between platelet activation and endothelial function, suggesting that some compensatory redundancy may exist in the relationship between platelet and endothelial function in preclinical populations.

CD40 in coronary artery disease: a matter of macrophages?

Coronary artery disease (CAD), also known as ischemic heart disease (IHD), is the leading cause of mortality in the western world, with developing countries showing a similar trend. With the increased understanding of the role of the immune system and inflammation in coronary artery disease, it was shown that macrophages play a major role in this disease. Costimulatory molecules are important regulators of inflammation, and especially, the CD40L-CD40 axis is of importance in the pathogenesis of cardiovascular disease. Although it was shown that CD40 can mediate macrophage function, its exact role in macrophage biology has not gained much attention in cardiovascular disease. Therefore, the goal of this review is to give an overview on the role of macrophage-specific CD40 in cardiovascular disease, with a focus on coronary artery disease. We will discuss the function of CD40 on the macrophage and its (proposed) role in the reduction of atherosclerosis, the reduction of neointima formation, and the stimulation of arteriogenesis.

Soluble CD40L is associated with insulin resistance, but not with glucose tolerance in obese nondiabetic patients

OBJECTIVE

The soluble platelet secreted ligand CD40 (sCD40L) has a role in atherosclerosis progression. The aim of the present study was to investigate the link between the levels of sCD40L and some classical cardiovascular risk factors in obese nondiabetic patients.

METHODS

In the present cross-sectional study, we included76 patients with mean age of 50.7 ± 10.7 years. Oral glucose tolerance test (OGTT) was performed in all participants and levels of sCD40L were measured using enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

We found significantly higher levels in patients with insulin resistance compared to those without (6.4 ± 3.7 vs. 4.1 ± 2.4 ng/ml, р = 0.025) and only a tendency toward higher levels in prediabetes compared to normoglycemic patients (5.9 ± 3.6 vs. 5.3 ± 3.4 ng/ml). There was no correlation between sCD40L and platelet count, systolic and diastolic blood pressure and lipid profile.

CONCLUSIONS

The main factor for increased sCD40L plasma levels was the presence of insulin resistance and not the state of glucose tolerance.

Role of Kir2.1 in human monocyte-derived foam cell maturation

The role of K⁺ channels in macrophage immunomodulation has been well‐established. However, it remains unclear whether K⁺ channels are involved in the lipid uptake of macrophages. The expression and function of the inward rectifier potassium channel (Kir2.1, KCNJ2) in Human acute monocytic leukemia cell line (THP‐1) cells and human monocytes derived macrophages (HMDMs) were investigated using RT‐PCR and western blotting, and patch clamp technique. The expression of scavenger receptors in THP‐1–derived macrophages was detected using western blotting. Expressions of Kir2.1 mRNA and protein in HMDMs were significantly decreased by 60% (P < 0.05) and 90% (P < 0.001) on macrophage maturation, but overexpressed by approximately 1.3 (P > 0.05) and 3.8 times (P = 0.001) after foam cell formation respectively. Concurrently, the Kir2.1 peak current density in HMDMs, mature macrophages and foam cells, measured at −150 mV, were −22.61 ± 2.1 pA/pF, −7.88 ± 0.60 pA/pF and −13.39 ± 0.80 pA/pF respectively (P < 0.05). In association with an up‐regulation of Kir2.1 in foam cells, the SR‐A protein level was significantly increased by over 1.5 times compared with macrophages (P < 0.05). THP‐1 cells contained much less lipids upon Kir2.1 knockdown and cholesterol ester/total cholesterol ratio was 29.46 ± 2.01% (P < 0.05), and the SR‐BI protein level was increased by over 6.2 times, compared to that of macrophages (P < 0.001). Kir2.1 may participate in macrophage maturation and differentiation, and play a key role in lipid uptake and foam cell formation through modulating the expression of scavenger receptors.