The role of glucose metabolism and insulin resistance in cardiac remodelling induced by cigarette smoke exposure

GPS2 ameliorates cigarette smoking-induced pulmonary vascular remodeling by modulating the ras-Raf-ERK axis

BACKGROUND

Mitogen-activated protein kinase (MAPK)signaling-mediated smoking-associated pulmonary vascular remodeling (PVR) plays an important role in the pathogenesis of group 3 pulmonary hypertension (PH). And G protein pathway suppressor 2 (GPS2) could suppress G-protein signaling such as Ras and MAPK, but its role in cigarette smoking -induced PVR (CS-PVR) is unclear.

METHODS

An in vivo model of smoke-exposed rats was constructed to assess the role of GPS2 in smoking-induced PH and PVR. In vitro, the effects of GPS2 overexpression and silencing on the function of human pulmonary arterial smooth cells (HPASMCs) and the underlying mechanisms were explored.

RESULTS

GPS2 expression was downregulated in rat pulmonary arteries (PAs) and HPASMCs after CS exposure. More importantly, CS-exposed rats with GPS2 overexpression had lower right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), and wall thickness (WT%) than those without. And enhanced proliferation and migration of HPASMCs induced by cigarette smoking extract (CSE) can be evidently inhibited by overexpressed GPS2. Besides, GPS2siRNA significantly enhanced the proliferation, and migration of HPASMCs as well as activated Ras and Raf/ERK signaling, while these effects were inhibited by zoledronic acid (ZOL). In addition, GPS2 promoter methylation level in rat PAs and HPASMCs was increased after CS exposure, and 5-aza-2-deoxycytidine (5-aza) inhibited CSE-induced GPS2 hypermethylation and downregulation in vitro.

CONCLUSIONS

GPS2 overexpression could improve the CS-PVR, suggesting that GPS2 might serve as a novel therapeutic target for PH-COPD in the future.

miR-153-3p via PIK3R1 Is Involved in Cigarette Smoke-Induced Neurotoxicity in the Brain

Cigarettes contain various chemicals that cause damage to nerve cells. Exposure to cigarette smoke (CS) causes insulin resistance (IR) in nerve cells. However, the mechanisms for a disorder in the cigarette-induced insulin signaling pathway and in neurotoxicity remain unclear. Therefore, we evaluated, by a series of pathology analyses and behavioral tests, the neurotoxic effects of chronic exposure to CS on C57BL/6 mice. Mice exposed to CS with more than 200 mg/m3 total particulate matter (TPM) exhibited memory deficits and cognitive impairment. Pathological staining of paraffin sections of mouse brain tissue revealed that CS-exposed mice had, in the brain, neuronal damage characterized by thinner pyramidal and granular cell layers and fewer neurons. Further, the exposure of SH-SY5Y cells to cigarette smoke extract (CSE) resulted in diminished insulin sensitivity and reduced glucose uptake in a dose-dependent fashion. The PI3K/GSK3 insulin signaling pathway is particularly relevant to neurotoxicity. microRNAs are involved in the PI3K/GSK3β/p-Tau pathway, and we found that cigarette exposure activates miR-153-3p, decreases PI3K regulatory subunits PIK3R1, and induces Tau hyperphosphorylation. Exposure to an miR-153 inhibitor or to a PI3K inhibitor alleviated the reduced insulin sensitivity caused by CS. Therefore, our results indicate that miR-153-3p, via PIK3R1, causes insulin resistance in the brain, and is involved in CS-induced neurotoxicity.

Cardiac function, myocardial fat deposition, and lipid profile in young smokers: a cross-sectional study

Background

There is a possibility that cardiac morphometric characteristics are associated with the lipid profile, that is, the composition and concentration of triglycerides, total cholesterol, HDL, LDL, and others lipoproteins in young smokers without comorbidities. Thus, this study aimed to evaluate the association of cardiac morphometric characteristics, myocardial fat deposition, and smoking cessation with the lipid profile of young smokers.

Methods

A clinical and laboratory evaluation of lipids and the smoking status was performed on 57 individuals, including both a smoker group and a control group. Cardiac magnetic resonance imaging (MRI) with proton spectroscopy was performed to identify cardiac changes and triglyceride (TG) deposition in myocardial tissue.

Results

No differences were observed between the groups (control vs. smokers) in relation to the amount of myocardial TG deposition (p = 0.47); however, when TG deposition was correlated with cardiac MRI variables, a positive correlation was identified between smoking history and myocardial TG deposition [hazard ratio (95% CI), 0.07 (0.03-0.12); p = 0.002]. Furthermore, it was observed that the smoking group had lower high-density lipoprotein cholesterol [51 (45.5-59.5) mg/dl vs. 43 (36-49.5) mg/dl, p = 0.003] and higher TG [73 (58-110) mg/dl vs. 122 (73.5-133) mg/dl, p = 0.01] and very-low-density lipoprotein cholesterol [14.6 (11.6-22.2) mg/dl vs. 24.4 (14.7-26.6) mg/dl, p = 0.01] values. In the control and smoking groups, a negative correlation between TGs and the diameter of the aortic root lumen and positive correlation with the thickness of the interventricular septum and end-diastolic volume (EDV) of both the right ventricle (RV) and left ventricle (LV) were noted. Moreover, in the RV, positive correlations with the end-systolic volume (ESV) index (ESVI), stroke volume (SV), ESV, and EDV were observed. Regarding serum free fatty acids, we found a negative correlation between their values and the diameter of the lumen of the ascending aortic vessel. Lipoprotein lipase showed a positive correlation with the SV index of the RV and negative correlation with the diameter of the lumen of the ascending aortic vessel.

Conclusion

Several associations were observed regarding cardiac morphometric characteristics, myocardial fat deposition, and smoking cessation with the lipid profile of young smokers.

Exercise Training Upregulates Cardiac mtp Expression in Drosophila melanogaster with HFD to Improve Cardiac Dysfunction and Abnormal Lipid Metabolism

Current evidence suggests that the heart plays an important role in regulating systemic lipid homeostasis, and high-fat diet (HFD)-induced obesity is a major cause of cardiovascular disease, although little is known about the specific mechanisms involved. Exercise training can reportedly improve abnormal lipid metabolism and cardiac dysfunction induced by high-fat diets; however, the molecular mechanisms are not yet understood. In the present study, to explore the relationship between exercise training and cardiac mtp in HFD flies and potential mechanisms by which exercise training affects HFD flies, Drosophila was selected as a model organism, and the GAL4/UAS system was used to specifically knock down the target gene. Experiments revealed that HFD-fed Drosophila exhibited changes in body weight, increased triglycerides (TG) and dysregulated cardiac contractility, consistent with observations in mammals. Interestingly, inhibition of cardiac mtp expression reduced HFD-induced cardiac damage and mitigated the increase in triglycerides. Further studies showed that in HFD +w1118, HFD + Hand > w1118, and HFD+ Hand > mtpRNAi, cardiac mtp expression downregulation induced by HFD was treated by exercise training and mitochondrial β-oxidation capacity in cardiomyocytes was reversed. Overall, knocking down mtp in the heart prevented an increase in systemic TG levels and protected cardiac contractility from damage caused by HFD, similar to the findings observed after exercise training. Moreover, exercise training upregulated the decrease in cardiac mtp expression induced by HFD. Increased Had1 and Acox3 expression were observed, consistent with changes in cardiac mtp expression.

An integral perspective of canonical cigarette and e-cigarette-related cardiovascular toxicity based on the adverse outcome pathway framework

BACKGROUND

Nowadays, cigarette smoking remains the leading cause of chronic disease and premature death, especially cardiovascular disease. As an emerging tobacco product, e-cigarettes have been advocated as alternatives to canonical cigarettes, and thus may be an aid to promote smoking cessation. However, recent studies indicated that e-cigarettes should not be completely harmless to the cardiovascular system.

AIM OF REVIEW

This review aimed to build up an integral perspective of cigarettes and e-cigarettes-related cardiovascular toxicity.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review adopted the adverse outcome pathway (AOP) framework as a pivotal tool and aimed to elucidate the association between the molecular initiating events (MIEs) induced by cigarette and e-cigarette exposure to the cardiovascular adverse outcome. Since the excessive generation of reactive oxygen species (ROS) has been widely approved to play a critical role in cigarette smoke-related CVD and may also be involved in e-cigarette-induced toxic effects, the ROS overproduction and subsequent oxidative stress are regarded as essential parts of this framework. As far as we know, this should be the first AOP framework focusing on cigarette and e-cigarette-related cardiovascular toxicity, and we hope our work to be a guide in exploring the biomarkers and novel therapies for cardiovascular injury.

Electronic and Conventional Cigarette Exposure Aggravate Metabolic Parameters in High-Fat Diet-Induced Rats

BACKGROUND: The health implications of the perceived use of electronic cigarettes (e-cigarettes) are safer than conventional cigarettes on metabolic parameters are not clearly understood. The current study evaluates the metabolic parameters as the impact of cigarette and e-cigarette exposure in high-fat-diet (HFD)-induced rats. METHODS: Twenty-four male Wistar rats were divided into four groups: i) NC: normal control group; ii) HFD Alone; iii) HFD + Cig and iv) HFD + E-Cig, administered HFD followed by cigarette or e-cigarette exposure, respectively. Six cigarettes stick with nicotine 2 mg/stick and 2 ml of e-cigarette liquid with nicotine 6 mg/ml were used for 25 cycles of exposure. In the end, the rats were sacrificed and obtained blood for metabolic parameter analysis, consisting of lipid profile, glucose, uric acid, urea, creatinine, aspartate transaminase (AST), and alanine transaminase (ALT). Statistical analysis with One-Way ANOVA with post hoc was used for high-density lipoprotein (HDL), triglyceride, total cholesterol, glucose, uric acid, urea, and creatinine. Furthermore, Kruskal-Wallis with Mann-Whitney U was used for nonparametric data such as low-density lipoprotein (LDL), AST, and ALT. RESULTS: Data of all metabolic parameters were shown a significant increase in the group of HFD Alone, HFD + Cig, and HFD + E-Cig, otherwise HDL levels. Furthermore, HFD + Cig followed by HFD + E-Cig groups were significantly higher compared to HFD Alone group. CONCLUSION: E-cigarettes were shown to be less harmful than conventional cigarettes but did not guarantee it was safe. Both cigarettes and e-cigarettes aggravated metabolic parameters in HFD-induced rats.