Tobacco smoking and cytokine levels in human epicardial adipose tissue: Impact of smoking cessation

Effect of smoking behaviour and related blood DNA methylation on visceral adipose tissues

BACKGROUND

Recent studies have found that tobacco smoking is associated with fat distribution, yet limited research has focused on its relationship with visceral adipose tissues (VATs). Furthermore, the cellular and molecular mechanisms underlying the interactions among smoking, epigenetic modifications, and VATs remain unknown.

METHOD

We performed univariable Mendelian randomization (MR) analysis to elucidate the causal relationship between smoking behaviours and VATs, including epicardial and pericardial adipose tissue (EPAT), liver fat (LF), and pancreas fat (PF). This approach could minimize the impact of confounders and reverse causality through utilizing genetic variants to proxy the smoking behaviours. Mediation MR analysis were conducted to detect potential mediators. Additionally, summary-data-based MR (SMR) and colocalization analysis were performed to explore the association between smoking-related DNA methylation and VATs.

RESULTS

We identified a convincing association between smoking initiation and increased EPAT (beta: 0.15, 95% CI: 0.06, 0.23, p = 7.01 × 10-4) and LF area (beta: 0.15, 95% CI = 0.05, 0.24, p = 2.85 × 10-3), respectively. Further mediation analysis suggested type 2 diabetes mellitus (T2DM) as a potential mediator within these co-relationships. When further exploring the associations between the smoking related DNA methylation and VATs, we identified that WT1 methylation at cg05222924 was significantly linked to a lower EPAT area (beta: -0.12, 95% CI: -0.16, -0.06, PFDR = 2.24 × 10-3), while GPX1 methylation at cg18642234 facilitated the deposition of EPAT (beta: 0.15, 95% CI: 0.10, 0.20, PFDR = 1.66 × 10-4).

CONCLUSION

Our study uncovered a significant causal effect between smoking and VATs, with T2DM identified as a potential mediator. Further investigation into DNA methylation yielded novel insights into the pathogenic role of smoking on EPAT.

Resistin concentrations in perivascular adipose tissue as a highly sensitive marker of smoking status in patients with advanced coronary artery disease requiring coronary artery bypass grafting

Background

Smoking is a significant risk factor for numerous diseases, including coronary artery disease (CAD). Chronic inflammation from smoking affects endothelial function and may alter adipokine secretion, particularly resistin, in perivascular adipose tissue (PVAT). This study investigated the association between resistin concentrations in PVAT and smoking status in CAD patients undergoing coronary artery bypass grafting (CABG).

Methods

The study included 110 patients with advanced CAD scheduled for CABG. Patients were categorized into never-smokers and ever-smokers, with the latter further divided into current and past smokers. Resistin concentrations in PVAT and plasma, along with plasma interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP) concentrations, were measured using ELISA.

Result

Significant differences in PVAT resistin concentrations were observed between never-smokers and ever-smokers (p < 0.0001), as well as between never-smokers and both current (p < 0.0001) and past smokers (p < 0.0001). PVAT resistin concentrations correlated positively with the number of pack-years (p < 0.0001) and plasma resistin (p < 0.0001) and IL-6 concentrations (p < 0.0001). Plasma resistin, IL-6, and hs-CRP concentrations were higher in ever-smokers compared with never-smokers. Multiple regression analysis indicated that smoking is significantly correlated with higher PVAT resistin concentrations, with increased pack-years (p = 0.0002), higher plasma resistin concentrations (p < 0.0001), and IL-6 concentrations (p < 0.0001), all contributing to elevated PVAT resistin.

Conclusion

Smoking status in advanced CAD patients requiring CABG is positively associated with PVAT resistin concentrations, with a clear demonstration of dose-dependency.

Electronic Cigarette Use and the Risk of Cardiovascular Diseases

Electronic cigarettes or e-cigarettes are the most frequently used tobacco product among adolescents. Despite the widespread use of e-cigarettes and the known detrimental cardiac consequences of nicotine, the effects of e-cigarettes on the cardiovascular system are not well-known. Several in vitro and in vivo studies delineating the mechanisms of the impact of e-cigarettes on the cardiovascular system have been published. These include mechanisms associated with nicotine or other components of the aerosol or thermal degradation products of e-cigarettes. The increased hyperlipidemia, sympathetic dominance, endothelial dysfunction, DNA damage, and macrophage activation are prominent effects of e-cigarettes. Additionally, oxidative stress and inflammation are unifying mechanisms at many levels of the cardiovascular impairment induced by e-cigarette exposure. This review outlines the contribution of e-cigarettes in the development of cardiovascular diseases and their molecular underpinnings.

Effects of Cigarette Smoking on Influenza Virus/Host Interplay

Cigarette smoking has been shown to increase the risk of respiratory infection, resulting in the exacerbation of infectious disease outcomes. Influenza viruses are a major respiratory viral pathogen, which are responsible for yearly epidemics that result in between 20,000 and 50,000 deaths in the US alone. However, there are limited general summaries on the impact of cigarette smoking on influenza pathogenic outcomes. Here, we will provide a systematic summarization of the current understanding of the interplay of smoking and influenza viral infection with a focus on examining how cigarette smoking affects innate and adaptive immune responses, inflammation levels, tissues that contribute to systemic chronic inflammation, and how this affects influenza A virus (IAV) disease outcomes. This summarization will: (1) help to clarify the conflict in the reports on viral pathogenicity; (2) fill knowledge gaps regarding critical anti-viral defenses such as antibody responses to IAV; and (3) provide an updated understanding of the underlying mechanism behind how cigarette smoking influences IAV pathogenicity.

Chronic Inflammation and Cancer: The Role of Endothelial Dysfunction and Vascular Inflammation

Long-lasting subclinical inflammation is associated with a wide range of human diseases, particularly at a middle and older age. Recent reports showed that there is a direct causal link between inflammation and cancer development, as several cancers were found to be associated with chronic inflammatory conditions. In patients with cancer, healthy endothelial cells regulate vascular homeostasis, and it is believed that they can limit tumor growth, invasiveness, and metastasis. Conversely, dysfunctional endothelial cells that have been exposed to the inflammatory tumor microenvironment can support cancer progression and metastasis. Dysfunctional endothelial cells can exert these effects via diverse mechanisms, including dysregulated adhesion, permeability, and activation of NF-κB and STAT3 signaling. In this review, we highlight the role of vascular inflammation in predisposition to cancer within the context of two common disease risk factors: obesity and smoking. In addition, we discuss the molecular triggers, pathophysiological mechanisms, and the biological consequences of vascular inflammation during cancer development and metastasis. Finally, we summarize the current therapies and pharmacological agents that target vascular inflammation and endothelial dysfunction.

Increased Pericardial Adipose Tissue in Smokers

BACKGROUND

Pericardial adipose tissue (PAT), a visceral fat depot directly located to the heart, is associated with atherosclerotic and inflammatory processes. The extent of PAT is related to the prevalence of coronary heart disease and might be used for cardiovascular risk prediction. This study aimed to determine the effect of smoking on the extent of PAT.

METHODS

We retrospectively examined 1217 asymptomatic patients (490 females, age 58.3 ± 8.3 years, smoker n = 573, non-smoker n = 644) with a multislice CT scanner and determined the PAT volume. Coronary risk factors were determined at inclusion, and a multivariate analysis was performed to evaluate the influence of smoking on PAT independent from accompanying risk factors.

RESULTS

The mean PAT volume was 215 ± 107 mL in all patients. The PAT volume in smokers was significantly higher compared to PAT volume in non-smokers (231 ± 104 mL vs. 201 ± 99 mL, p = 0.03). Patients without cardiovascular risk factors showed a significantly lower PAT volume (153 ± 155 mL, p < 0.05) compared to patients with more than 1 risk factor. Odds ratio was 2.92 [2.31, 3.61; p < 0.001] for elevated PAT in smokers.

CONCLUSION

PAT as an individual marker of atherosclerotic activity and inflammatory burden was elevated in smokers. The finding was independent from metabolic risk factors and might therefore illustrate the increased inflammatory activity in smokers in comparison to non-smokers.

Smoking habits and progression of coronary and aortic artery calcification: A 5-year follow-up of community-dwelling Japanese men

BACKGROUND AND AIMS

To examine whether smoking habits, including smoking amount and cessation duration at baseline, are associated with atherosclerosis progression.

METHODS

At baseline (2006-08, Japan), we obtained smoking status, amount of smoking and time since cessation for quitters in a community-based random sample of Japanese men initially aged 40-79 years and free of cardiovascular disease. Coronary artery calcification (CAC) and aortic artery calcification (AAC) as biomarker of atherosclerosis was quantified using Agatston's method at baseline and after 5 years of follow-up. We defined progression of CAC and AAC (yes/no) using modified criteria by Berry.

RESULTS

A total of 781 participants was analyzed. Multivariable adjusted odds ratios (ORs) of CAC and AAC progression for current smokers were 1.73 (95% CI, 1.09-2.73) and 2.47 (1.38-4.44), respectively, as compared to never smokers. In dose-response analyses, we observed a graded positive relationship of smoking amount and CAC progression in current smokers (multivariable adjusted ORs: 1.23, 1.72, and 2.42 from the lowest to the highest tertile of pack-years). Among the former smokers, earlier quitters (≥10.7 years) had similar ORs of the progression of CAC and AAC to that of participants who had never smoked.

CONCLUSIONS

Compared with never smokers, current smokers especially those with greater pack-years at baseline had higher risk of atherosclerosis progression in community-dwelling Japanese men. Importantly, the residual adverse effect appears to be present for at least ten years after smoking cessation. The findings highlight the importance of early avoidance or minimizing smoking exposure for the prevention of atherosclerotic disease.

Environmental Tobacco Smoke Exposure Estimated Using the SHSES Scale and Epicardial Adipose Tissue Thickness in Hypertensive Patients

The aim of the study was to assess the relationship between environmental tobacco smoke exposure (ETS) and epicardial adipose tissue thickness (EATT) in hypertensive patients. A total of 96 patients with essential hypertension were recruited for this study. The group consisted of 48 females and 48 males with the mean age of 69.32 ± 9.54 years. ETS was assessed with The Secondhand Smoke Exposure Scale (SHSES). EATT was assessed in 128-slice dual source coronary computed tomography angiography. In accordance to SHSES scale patients were divided into subgroups: subgroup A-no ETS exposure (SHSES = 0 points, n = 48), subgroup B-low ETS exposure (SHSES = 1-3 points, n = 11), subgroup C-medium ETS exposure (SHSES = 4-7 points, n = 20) and subgroup D-high ETS exposure (SHSES = 8-11 points, n = 17). Within the study group the mean EATT was 5.75 ± 1.85 mm and the mean SHSES score was 3.05 ± 3.74. EATT was statistically significantly higher in subgroup D than in subgroups A and B (A: 5.28 ± 1.64 mm, B: 5.04 ± 2.64 mm, D: 7.04 ± 2.64 mm, p_A-D and p_B-D < 0.05). There was a positive linear correlation between the exposure to ETS expressed by the SHSES scale and EATT (r = 0.44, p < 0.05). Regression analysis showed that higher SHSES score, higher BMI, and higher systolic and diastolic blood pressure are independent risk factors for higher EATT values. Contrary, the use of ACE inhibitors and β-blockers appeared to be independent protecting factor against higher EATT values. There is an unfavorable positive relationship between ETS exposure estimated using the SHSES scale and EATT in hypertensive patients.

Differential packaging of inflammatory cytokines/ chemokines and oxidative stress modulators in U937 and U1 macrophages-derived extracellular vesicles upon exposure to tobacco constituents

Smoking, which is highly prevalent in HIV-infected populations, has been shown to exacerbate HIV replication, in part via the cytochrome P450 (CYP)-induced oxidative stress pathway. Recently, we have shown that extracellular vesicles (EVs), derived from tobacco- and/or HIV-exposed macrophages, alter HIV replication in macrophages by cell-cell interactions. We hypothesize that cigarette smoke condensate (CSC) and/or HIV-exposed macrophage-derived EVs carry relatively high levels of pro-oxidant and pro-inflammatory cargos and/or low levels of antioxidant and anti-inflammatory cargos, which are key mediators for HIV pathogenesis. Therefore, in this study, we investigated differential packaging of pro- and anti-inflammatory cytokines/chemokines and pro- and anti-oxidant contents in EVs after CSC exposure to myeloid cells (uninfected U937 and HIV-infected U1 cells). Our results showed that relatively long to short exposures with CSC increased the expression of cytokines in EVs isolated from HIV-infected U1 macrophages. Importantly, pro-inflammatory cytokines, especially IL-6, were highly packaged in EVs isolated from HIV-infected U1 macrophages upon both long and short-term CSC exposures. In general, anti-inflammatory cytokines, particularly IL-10, had a lower packaging in EVs, while packaging of chemokines was mostly increased in EVs upon CSC exposure in both HIV-infected U1 and uninfected U937 macrophages. Moreover, we observed higher expression of CYPs (1A1 and 1B1) and lower expression of antioxidant enzymes (SOD-1 and catalase) in EVs from HIV-infected U1 macrophages than in uninfected U937 macrophages. Together, they are expected to increase oxidative stress factors in EVs derived from HIV-infected U1 cells. Taken together, our results suggest packaging of increased level of oxidative stress and inflammatory elements in the EVs upon exposure to tobacco constituents and/or HIV to myeloid cells, which would ultimately enhance HIV replication in macrophages via cell-cell interactions.

Tumour necrosis factor like cytokine 1A levels and lesion complexity in non-smoking patients with coronary artery disease

Background: Tumour necrosis factor like cytokine 1A (TL1A), which is a member of tumour necrosis factor alpha superfamily (TNF-α), is a novel indicator of atherosclerosis.Objective: Smoking is an established stimulant of TNF-α. We aimed to investigate whether TLA1 plays a role in the presence and complexity of coronary artery atherosclerosis, exclusively in non-smoking patients with CAD.Methods: We enrolled 103 participants in the study, who underwent coronary angiography for stable angina pectoris. We divided the study population into 2 groups: The CAD group consisted of 62 patients with CAD and the control group consisted of 41 subjects with non-CAD. SYNTAX and Gensini scores, indicating CAD severity and complexity, were analysed as well as TLA1 levels.Results: TLA1 levels was higher in patients with CAD than those in controls (228[119-824] vs 178[15-418]pg/ml, p < 0.001). Presence of CAD (β ± SE = 106.29 ± 33.11, p = 0.002), Syntax score (β ± SE= 6.57 ± 1.75, p = 0.012), and Gensini score (β ± SE = 2.30 ± 0.65, p = 0.001) were found to be predictors of TL1A levels. Gensini score and Syntax score were positively correlated with TL1A levels (r = 0.420, p < 0.001, and r = 0.402, p < 0.001, respectively).Conclusions: Non-smoker CAD patients have higher TLA1 levels that are promising biomarker for diagnosing CAD and indicating CAD lesion complexity.

Statins Reduce Epicardial Adipose Tissue Attenuation Independent of Lipid Lowering: A Potential Pleiotropic Effect

Background

High epicardial adipose tissue (EAT) attenuation (Hounsfield units [HUs]) on computed tomography is considered a marker of inflammation and is associated with an increased risk of cardiovascular events. Statins reduce the volume of EAT, but it is unknown whether they affect EAT HUs.

Methods and Results

We reviewed the chest computed tomographic scans of 420 postmenopausal women randomized to either 80 mg of atorvastatin or 40 mg of pravastatin daily and rescanned after 1 year to measure change in coronary artery calcium score. EAT HUs were measured near the proximal right coronary artery and remote from any area of coronary artery calcium. Computed tomographic images were also queried for subcutaneous adipose tissue (SubQ) attenuation (HUs) change over time. The mean patients’ age was 65±6 years. The baseline EAT HU value was higher than the SubQ HU value (−89.4±24.0 HU versus −123.3±30.4 HU; P<0.001). The EAT HU value decreased significantly in the entire cohort (−5.4±29.7 HU [−6% change]; P<0.001), but equally in the patients given atorvastatin and pravastatin (−6.35+31 HU and −4.55+28 HU; P=0.55). EAT HU change was not associated with change in total cholesterol, low‐density lipoprotein cholesterol, coronary artery calcium, and EAT volume (all P=not significant). Change in high‐density lipoprotein cholesterol was marginally associated with EAT HU change (P=0.07). Statin treatment did not induce a change in SubQ HUs.

Conclusions

Statins induced a decrease in EAT HUs over time, independent of intensity of low‐density lipoprotein cholesterol lowering. The positive effect on EAT and the neutral effect on SubQ suggest that statins induced a decrease in metabolic activity in EAT by reduction in cellularity, vascularity, or inflammation. The clinical significance of the observed change in EAT HUs remains to be demonstrated.

Epicardial fat, cardiovascular risk factors and calcifications in patients with chronic kidney disease

Background

Epicardial adipose tissue (EAT) exerts cardiopathogenic effects, but the independent association between EAT and cardiovascular (CV) calcification in patients with chronic kidney disease (CKD) remains controversial. We therefore assessed the association between EAT, CV risk factors and CV calcifications.

Methods

257 patients with CKD Stage 3 and/or overt proteinuria underwent quantification of EAT, coronary artery calcification and aortic valve calcification by computed tomography. Framingham and American College of Cardiology and American Heart Association (ACC-AHA) 10-year CV event risk scores were calculated for each patient.

Results

Using multivariable regression analysis, higher EAT was significantly associated with the majority of investigated risk factors {higher age: odds ratio [OR] 1.05/year [95% confidence interval (CI) 1.02-1.08]; male sex: OR 4.03 [95% CI 2.22-7.31]; higher BMI: OR 1.28/kg/m² [95% CI 1.20-1.37]; former smoking: OR 1.84 [95% CI 1.07-3.17]; lower high-density lipoprotein cholesterol: OR 0.98/mg/dL [95% CI 0.96-1.00] and lower estimated glomerular filtration rate: OR 0.98/mL/min/1.73 m² [95% CI 0.97-0.99]; all P < 0.05} and was not associated with diabetes mellitus, hypertensive nephropathy, total cholesterol and albuminuria. EAT was positively associated with higher ACC-AHA and Framingham risk scores. EAT correlated with coronary artery calcification and aortic valve calcification [Spearman ρ = 0.388 (95% CI 0.287-0.532) and r _rb = 0.409 (95% CI 0.310-0.556), respectively], but these correlations were dependent on CV risk factors.

Conclusions

The increase of EAT can be explained by individual CV risk factors and kidney function and correlates with 10-year risk for CV event scores, suggesting that EAT is a modifiable risk factor in patients with CKD. Although EAT correlates with CV calcifications, these relations depend on CV risk factors.

Clinical Characteristics of Nonobese Patients with Acute Coronary Syndrome and Increased Epicardial Fat Volume

Aim: Increased epicardial fat volume (EFV) is an independent risk factor for acute coronary syndrome (ACS). Although EFV increases with body mass index (BMI), some ACS patients have an increased EFV but normal BMI. We here investigated the clinical characteristics of nonobese ACS patients with an increased EFV.

Methods: A total of 197 Japanese patients hospitalized for ACS was evaluated for EFV, abdominal visceral fat area (VFA), and lipid and glucose profiles. Control subjects comprised 141 individuals who were suspected of having ACS but whose coronary computed tomography findings were normal.

Results: EFV was increased in ACS patients compared with control subjects (120 ± 47 versus 95 ± 45 mL, P < 0.01). ACS patients were divided into four groups based on average EFV (120 mL) and a BMI obesity cutoff of 25 kg/m². For the 30 nonobese ACS patients with an above-average EFV, EFV was positively correlated with VFA (r = 0.23, P = 0.031). These individuals were significantly older (74 ± 10 years) and tended to have a higher homeostasis model assessment–insulin resistance value (5.5 ± 3.8) compared with other ACS patients. Among nonobese study subjects, EFV was independently associated with ACS (odds ratio= 2.01, P = 0.021) and correlated with abdominal circumference (r = 0.26, P = 0.017).

Conclusion: Nonobese ACS patients with an increased EFV were elderly and tended to manifest insulin resistance. Measurement of EFV may prove informative for evaluation of ACS risk among elderly nonobese individuals with an increased abdominal girth.

Epicardial Adipose Tissue May Mediate Deleterious Effects of Obesity and Inflammation on the Myocardium

Epicardial adipose tissue has unique properties that distinguish it from other depots of visceral fat. Rather than having distinct boundaries, the epicardium shares an unobstructed microcirculation with the underlying myocardium, and in healthy conditions, produces cytokines that nourish the heart. However, in chronic inflammatory disorders (especially those leading to heart failure with preserved ejection fraction), the epicardium becomes a site of deranged adipogenesis, leading to the secretion of proinflammatory adipokines that can cause atrial and ventricular fibrosis. Accordingly, in patients at risk of heart failure with preserved ejection fraction, drugs that promote the accumulation or inflammation of epicardial adipocytes may lead to heart failure, whereas treatments that ameliorate the proinflammatory characteristics of epicardial fat may reduce the risk of heart failure. These observations suggest that epicardial adipose tissue is a transducer of the adverse effects of systemic inflammation and metabolic disorders on the heart, and thus, represents an important target for therapeutic interventions.

The influence of KIR gene presence/absence polymorphisms on the development of periodontal disease in smokers and non-smokers

Introduction

Periodontal diseases are highly prevalent inflammatory, multifactorial diseases. Smoking is one of the most important environmental risk factors for the development and severity of periodontal disease. Killer cell immunoglobulin-like receptors (KIRs) are members of the immunoglobulin (Ig) superfamily and play an essential role in the regulation of NK cell activity, allowing natural killer (NK) cells to sense and respond to human leukocyte antigen (HLA) class I. The aim of this study was to evaluate the influence of KIR gene presence/absence polymorphisms on the development of periodontal disease in smokers and non-smokers.

Material and methods

This study enrolled 400 Caucasian subjects (age range 25-69 years) from the West Pomeranian region of Poland. The subjects were categorized into four subgroups (smoking and non-smoking patients with periodontal disease; smoking and non-smoking subjects without periodontal disease - control subjects).

Results

The differences of KIR gene frequencies between non-smoking patients and non-smoking control subjects as well as smoking patients and control subjects were not statistically significant. In multivariate regression analysis advanced age of patients and smoking were independent factors associated with increased frequency of periodontal disease.

Conclusions

The results of this study suggest that the main factor associated with increased risk of periodontal disease is smoking, whereas KIR presence/absence polymorphism is not a significant factor involved in the pathogenesis of periodontal disease.

Cigarette Smoking and Adipose Tissue: The Emerging Role in Progression of Atherosclerosis

Smoking is an established risk factor for atherosclerosis through several underlying pathways. Moreover, in the development of atherosclerotic plaque formation, obesity, defined as excess fat mass accumulation, also plays a vital role in dyslipidemia and insulin resistance. Substantial evidence shows that cigarette smoking induces multiple pathological effects in adipose tissue, such as differentiation of adipocytes, lipolysis, and secretion properties in adipose tissue. Therefore, there is an emerging speculation in which adipose tissue abnormality induced by smoking or nicotine is likely to accelerate the progression of atherosclerosis. Herein, this review aims to investigate the possible interplay between smoking and adipose tissue dysfunction in the development of atherosclerosis.