The role of lipotoxicity in smoke cardiomyopathy

Rhodiola and Salidroside Attenuate Oxidative Stress-Triggered H9c2 Cardiomyoblast Apoptosis Through IGF1R-Induced ERK1/2 Activation

Oxidative stress is a pivotal factor in the pathogenesis of various cardiovascular diseases. Rhodiola, a traditional Chinese medicine, is recognized for its potent antioxidant properties. Salidroside, a phenylpropanoid glycoside derived from Rhodiola rosea, has shown remarkable antioxidant capabilities. This study aimed to elucidate the potential protective mechanisms of Rhodiola and salidroside against H2O2-induced cardiac apoptosis in H9c2 cardiomyoblast cells. H9c2 cells were exposed to H2O2 for 4 h, and subsequently treated with Rhodiola or salidroside for 24 h. Cell viability and apoptotic pathways were assessed. The involvement of insulin-like growth factor 1 receptor (IGF1R) and the activation of extracellular regulated protein kinases 1/2 (ERK1/2) were investigated. H2O2 (100 μM) exposure significantly induced cardiac apoptosis in H9c2 cells. However, treatment with Rhodiola (12.5, 25, and 50 μg/mL) and salidroside (0.1, 1, and 10 nM) effectively attenuated H2O2-induced cytotoxicity and apoptosis. This protective effect was associated with IGF1R-activated phosphorylation of ERK1/2, leading to the inhibition of Fas-dependent proteins, HIF-1α, Bax, and Bak expression in H9c2 cells. The images from hematoxylin and eosin staining and immunofluorescence assays also revealed the protective effects of Rhodiola and salidroside in H9c2 cells against oxidative damage. Our findings suggest that Rhodiola and salidroside possess antioxidative properties that mitigate H2O2-induced apoptosis in H9c2 cells. The protective mechanisms involve the activation of IGF1R and subsequent phosphorylation of ERK1/2. These results propose Rhodiola and salidroside as potential therapeutic agents for cardiomyocyte cytotoxicity and apoptosis induced by oxidative stress in heart diseases. Future studies may explore their clinical applications in cardiac health.

Omega-3 supplementation attenuates doxorubicin-induced cardiotoxicity but is not related to the ceramide pathway

Cardiotoxicity is the serious side effect of doxorubicin treatment. Ceramides are formed from the degradation of sphingolipids in cell membranes and play an important role in signaling and modulating biological processes. There is evidence that omega-3 fatty acid administration can act on this pathway. To evaluate the role of the ceramide pathway in the pathophysiology of doxorubicin-induced cardiotoxicity and the effect of omega-3 fatty acid supplementation in the attenuation of chronic doxorubicin-induced cardiotoxicity in rats. Sixty male Wistar rats were divided into four groups: Control (C), Doxorubicin (D), Omega-3 fatty acids (W), and Doxorubicin + Omega-3 fatty acids (DW). The groups received omega-3 fatty acids (400 mg/kg/day, via gavage) or water for 6 weeks and doxorubicin (3.5 mg/kg, intraperitoneal) or saline once a week for 4 weeks. Doxorubicin-treated animals showed increases in left atrium and left ventricle diameters, serum triglycerides and cholesterol, malondialdehyde, and protein carbonylation. We also observed a decrease in left ventricular shortening fraction and nSMase1 expression in the heart. Omega-3 fatty acid supplementation attenuated the structural and functional alterations caused by doxorubicin and decreased protein carbonylation. In contrast to doxorubicin, omega-3 fatty acids increased neutral nSMase activity in animals that both received and did not receive doxorubicin but with no effect on nSMase1 protein expression. Omega-3 fatty acid supplementation attenuated the cardiotoxicity caused by doxorubicin. The ceramide pathway may be involved in the pathophysiology of cardiotoxicity, but it is not the mechanism by which omega-3 fatty acids attenuated cardiac dysfunction.

Harmful Impact of Tobacco Smoking and Alcohol Consumption on the Atrial Myocardium

Tobacco smoking and alcohol consumption are widespread exposures that are legal and socially accepted in many societies. Both have been widely recognized as important risk factors for diseases in all vital organ systems including cardiovascular diseases, and with clinical manifestations that are associated with atrial dysfunction, so-called atrial cardiomyopathy, especially atrial fibrillation and stroke. The pathogenesis of atrial cardiomyopathy, atrial fibrillation, and stroke in context with smoking and alcohol consumption is complex and multifactorial, involving pathophysiological mechanisms, environmental, and societal aspects. This narrative review summarizes the current literature regarding alterations in the atrial myocardium that is associated with smoking and alcohol.

Sex differences in cardiac remodeling post myocardial infarction with acute cigarette smoking

Background

Whether cigarette smoking affects the heart post-myocardial infarction (MI) in a sex-dependent way remains controversial. Using a mouse model, we investigated cardiac remodeling under the influence of acute cigarette smoke (CS) exposure following ischemic injury in both sexes.

Methods

Ten cigarettes were smoked twice daily for 2 weeks followed by MI and then 1 additional week post permanent LAD ligation. Cardiac function, histology, and infarct size were assessed, and inflammatory markers quantified by RT–PCR. Statistical comparisons were performed using an unpaired t test or ANOVA followed by Tukey post hoc test.

Results

We observed that cigarette smoking exacerbated both left and right ventricular remodeling only in males at an early stage of post-MI. Females did not display a significant structural and/or functional alteration within 7 days of cardiac remodeling post-MI upon CS exposure. Worsened right ventricular remodeling in males was independent of pulmonary congestion. CS-exposed males exhibited enhanced increases in left ventricular end systolic and diastolic volumes, as well as reductions in ejection fraction and fractional area changes of left ventricular base. At day 7, infarct size was increased by cigarette smoking in males only, which was accompanied by enhanced collagen deposition in both the infarcted and peri-infarcted areas. Both IL-6 and TNF-α mRNA expression significantly increased in CS-exposed MI male group only at day 7 post-MI suggestive of prolonged inflammation.

Conclusions

These findings indicate that CS exposure worsens the progression of cardiac remodeling post-MI in male sex in a significant manner compared to female sex at least at early stages.

Sodium-Glucose Cotransporter 2 Inhibitors and Cardiac Remodeling

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have evident cardiovascular benefits in patients with type 2 diabetes with or at high risk for atherosclerotic cardiovascular disease, heart failure with reduced ejection fraction, heart failure with preserved ejection fraction (only empagliflozin and dapagliflozin have been investigated in this group so far), and chronic kidney disease. Prevention and reversal of adverse cardiac remodeling is one of the mechanisms by which SGLT2 inhibitors may exert cardiovascular benefits, especially heart failure-related outcomes. Cardiac remodeling encompasses molecular, cellular, and interstitial changes that result in favorable changes in the mass, geometry, size, and function of the heart. The pathophysiological mechanisms of adverse cardiac remodeling are related to increased apoptosis and necrosis, decreased autophagy, impairments of myocardial oxygen supply and demand, and altered energy metabolism. Herein, the accumulating evidence from animal and human studies is reviewed investigating the effects of SGLT2 inhibitors on these mechanisms of cardiac remodeling.

Electronic and Tobacco Cigarettes Alter Polyunsaturated Fatty Acids and Oxidative Biomarkers

[Figure: see text].

Pera orange (Citrus sinensis) and Moro orange (Citrus sinensis (L.) Osbeck) juices attenuate left ventricular dysfunction and oxidative stress and improve myocardial energy metabolism in acute doxorubicin-induced cardiotoxicity in rats

OBJECTIVES

Doxorubicin is a highly effective chemotherapeutic agent for treating several types of cancer; however, it can induce cardiotoxicity. We evaluated the influence of Pera and Moro orange juices on cardiac remodeling induced by acute administration of doxorubicin in rats.

METHODS

We allocated 120 male Wistar rats into six groups: control (C), Pera orange juice (PO), Moro orange juice (MO), doxorubicin (D), doxorubicin + Pera orange juice (DPO), and doxorubicin + Moro orange juice (DMO). Groups PO and DPO received Pera orange juice, MO and DMO received Moro orange juice, and C and D received water with maltodextrin (100 g/L) for 4 wk. Subsequently, groups D, DPO, and DMO received 20 mg/kg doxorubicin and C, PO, and MO received saline. Echocardiogram and euthanasia were performed 48 h after doxorubicin injection. Juice and animal-serum flavonoid identification and quantification were evaluated by liquid chromatography/electrospray ionization multistage mass spectrometry. Oxidative stress and myocardial metabolism were evaluated by spectrophotometry.

RESULTS

Systolic and diastolic left ventricular dysfunction increased oxidative stress and pathologic changes in myocardial energy metabolism of rats treated with doxorubicin. Intake of both orange juices improved left ventricular function, decreased oxidative stress, and attenuated the myocardial energy metabolism changes. Moro orange juice had a more pronounced effect than Pera orange juice in glutathione peroxidase activity, citrate synthase, and β-hydroxyacyl-CoA dehydrogenase activity.

CONCLUSIONS

Pera and Moro orange juices attenuated cardiac remodeling induced by doxorubicin, improved myocardial energy metabolism, and attenuated oxidative stress. However, Moro orange juice was more effective than Pera orange juice in modifying energy metabolism.

Vitamin D Supplementation Induces Cardiac Remodeling in Rats: Association with Thioredoxin-Interacting Protein and Thioredoxin

BACKGROUND

Vitamin D (VD) has been shown to play an important role in cardiac function. However, this vitamin exerts a biphasic "dose response" curve in cardiovascular pathophysiology and may cause deleterious effects, even in non-toxic doses. VD exerts its cellular functions by binding to VD receptor. Additionally, it was identified that the thioredoxin-interacting protein (TXNIP) expression is positively regulated by VD. TXNIP modulate different cell signaling pathways that may be important for cardiac remodeling.

OBJECTIVE

To evaluate whether VD supplementation lead to cardiac remodeling and if TXNIP and thioredoxin (Trx) proteins are associated with the process.

METHODS

A total of 250 Male Wistar rats were allocated into three groups: control (C, n=21), with no VD supplementation; VD3 (n = 22) and VD10 (n=21), supplemented with 3,000 and 10,000 IU of VD/ kg of chow respectively, for two months. The groups were compared by one-way analysis of variance (ANOVA) and Holm-Sidak post hoc analysis, (variables with normal distribution), or by Kruskal-Wallis test and Dunn's test post hoc analysis. The significance level for all tests was 5%.

RESULTS

TXNIP protein expression was higher and Trx activity was lower in VD10. The animals supplemented with VD showed increased lipid hydroperoxide and decreased superoxide dismutase and glutathione peroxidase. The protein Bcl-2 was lower in VD10. There was a decrease in fatty acid β-oxidation, tricarboxylic acid cycle and electron transport chain with shift to increase in glycolytic pathway.

CONCLUSION

VD supplementation led to cardiac remodeling and this process may be modulated by TXNIP and Trx proteins and consequently oxidative stress.

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

The aim of this study is to evaluate whether the alterations in glucose metabolism and insulin resistance are mechanisms presented in cardiac remodelling induced by the toxicity of cigarette smoke. Male Wistar rats were assigned to the control group (C; n = 12) and the cigarette smoke-exposed group (exposed to cigarette smoke over 2 months) (CS; n = 12). Transthoracic echocardiography, blood pressure assessment, serum biochemical analyses for catecholamines and cotinine, energy metabolism enzymes activities assay; HOMA index (homeostatic model assessment); immunohistochemistry; and Western blot for proteins involved in energy metabolism were performed. The CS group presented concentric hypertrophy, systolic and diastolic dysfunction, and higher oxidative stress. It was observed changes in energy metabolism, characterized by a higher HOMA index, lower concentration of GLUT4 (glucose transporter 4) and lower 3-hydroxyl-CoA dehydrogenase activity, suggesting the presence of insulin resistance. Yet, the cardiac glycogen was depleted, phosphofructokinase (PFK) and lactate dehydrogenase (LDH) increased, with normal pyruvate dehydrogenase (PDH) activity. The activity of citrate synthase, mitochondrial complexes and ATP synthase (adenosine triphosphate synthase) decreased and the expression of Sirtuin 1 (SIRT1) increased. In conclusion, exposure to cigarette smoke induces cardiac remodelling and dysfunction. The mitochondrial dysfunction and heart damage induced by cigarette smoke exposure are associated with insulin resistance and glucose metabolism changes.

Short-Term Cigarette Smoking in Rats Impairs Physical Capacity and Induces Cardiac Remodeling

Despite the strong evidence on the cardiac and renal damages after chronic exposure to cigarette smoke, there is a paucity of data on its short-term effects. The study evaluated the short-term effects of cigarette smoking on left ventricular (LV) remodeling, in vitro myocardial and renal function. Female Wistar rats were randomized to control (C) and cigarette smoking rats for eight weeks. Physical capacity was assessed using an adapted model of exhaustive swim; left ventricle (LV) morphology and function were also evaluated. Renal function was assessed by creatinine clearance and urine protein. The in vitro myocardial performance was analyzed in isolated papillary muscles. Rats exhibited reduced physical capacity after short-term cigarette smoking. Although there was no change on LV function, reduced chamber diameter was found in the smoking group associated with an increased LV wall thickness. There was augmented cardiac mass compared to C that was confirmed by increased cardiomyocyte nucleus volume, but in vitro myocardial performance and renal function were unchanged. A short-term cigarette smoking induces cardiac remodeling without abnormalities in function. The smoking group still preserved renal function and in vitro myocardial performance. However, the reduced physical capacity may suggest an impairment of the cardiac reserve.

The flavoring and not the nicotine content is a decisive factor for the effects of refill liquids of electronic cigarette on the redox status of endothelial cells

•

The pattern of the effect on Ea.hy926 redox status differs among flavored e-liquids.

•

Tobacco flavored e-liquids increase ROS generation with concomitant increase in TBARS.

•

Vanilla flavored e-liquids profile depends on the nicotine content.

•

Apple/mint flavored e-liquids activate the cellular antioxidant defense.

•

Flavorings and not the nicotine content play a key role in free radical generation.

Electronic cigarettes are constantly gaining ground as they are considered less harmful than conventional cigarettes, and there is also the perception that they may serve as a potential smoking cessation tool. Although the acute effects of electronic cigarette use have been extensively studied, the long-term potential adverse effects on human health remain largely unknown. It has been well-established that oxidative stress is involved in the development of various pathological conditions. So far, most studies on e-cigarettes concern the effects on the respiratory system while fewer have focused on the vascular system. In the present study, we attempted to reveal the effects of electronic cigarette refill liquids on the redox state of human endothelial cells (EA.hy926 cell line). For this purpose, the cytotoxic effect of three e-liquids with different flavors (tobacco, vanilla, apple/mint) and nicotine concentrations (0, 6, 12, 18 mg/ml) were initially examined for their impact on cell viability of EA.hy926 cells. Then, five redox biomarkers [reduced form of glutathione (GSH), reactive oxygen species (ROS), total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS) and protein carbonyls (CARBS)] were measured. The results showed a disturbance in the redox balance in favor of free radicals in tobacco flavored e-liquids while vanilla flavored e-liquids exhibited a more complex profile depending on the nicotine content. The most interesting finding of the present study concerns the apple/mint flavored e-liquids that seemed to activate the cellular antioxidant defense and, thus, to protect the cells from the adverse effects of free radicals. Conclusively, it appears that the flavorings and not the nicotine content play a key role in the oxidative stress-induced toxicity of the e-liquids.

Abnormal left ventricular global strain during exercise-test in young healthy smokers

BACKGROUND

It is unknown how much precociously the cigarette smoking (CS) may compromise the integrity of the cardiovascular (CV) system. Myocardial function can be routinely assessed by conventional echocardiography, but abnormalities are only detected when somewhat a remodelling has already occurred. These limitations could be overcome by strain imaging.

METHODS

We evaluated whether young smokers with normal left ventricular (LV) geometry, wall motion and ejection fraction may present abnormalities in myocardial deformation, both at rest and during physical effort. We selected 50 young smokers with no additional CV risk factors, and 60 non-smokers to undergo a standardized exercise-test. Consistently, we evaluated the CV adaptation to exercise by both conventional echocardiography and speckle-tracking analysis (2D-STE).

RESULTS

We found no difference between smokers and controls regarding baseline characteristics; as expected, smokers presented with lower HDL-cholesterol (p < 0.005), and higher fibrinogen, C-reactive protein (CRP), and interleukin-6 (p < 0.001). Conventional echocardiography parameters were not different between groups, while we detected a different behaviour of global longitudinal strain (GLS), global circumferential strain (GCS) and twist by 2D-STE during exercise-test. Indeed, GLS, GCS and twist behaved differently during exercise test in smokers with respect to controls. We found an association between CS, inflammation and LV mechanics changes uncovered by physical effort, and regression analysis confirmed that the intensity of the exposure to cigarette smoking, together with the inflammatory status (CRP, fibrinogen and Il-6) plasma levels, drive this impairment.

CONCLUSIONS

We confirm strain imaging (2D-STE) as a very useful tool to identify early changes in cardiac mechanics, as adaptation to exercise; our findings may reflect a very precocious functional abnormality in active smokers, likely long before structural damage occurs.

Cocoa Flavonoids Reduce Inflammation and Oxidative Stress in a Myocardial Ischemia-Reperfusion Experimental Model

: Consumption of flavonoid-rich nutraceuticals has been associated with a reduction in coronary events. The present study analyzed the effects of cocoa flavonols on myocardial injury following acute coronary ischemia-reperfusion (I/R). A commercially available cocoa extract was identified by chromatographic mass spectrometry. Nineteen different phenolic compounds were identified and 250 mg of flavan-3-ols (procyanidin) were isolated in 1 g of extract. Oral administration of cocoa extract in incremental doses from 5 mg/kg up to 25 mg/kg daily for 15 days in Sprague Dawley rats (n = 30) produced a corresponding increase of blood serum polyphenols and become constant after 15 mg/kg. Consequently, the selected dose (15 mg/kg) of cocoa extract was administered orally daily for 15 days in a treated group (n = 10) and an untreated group served as control (n = 10). Both groups underwent surgical occlusion of the left anterior descending coronary artery and reperfusion. Cocoa extract treatment significantly reversed membrane peroxidation, nitro-oxidative stress, and decreased inflammatory markers (IL-6 and NF-kB) caused by myocardial I/R injury and enhanced activation of both p-Akt and p-Erk1/2. Daily administration of cocoa extract in rats is protective against myocardial I/R injury and attenuate nitro-oxidative stress, inflammation, and mitigates myocardial apoptosis.

Lipid damage is the best marker of oxidative injury during the cardiac remodeling process induced by tobacco smoke

BACKGROUND

Oxidative stress is one potential mechanism that explain the direct effects of smoking on cardiac remodeling process. However, no study has compared different myocardial products of macromolecule oxidation after tobacco smoke exposure. Thus, the aim of this study was to investigate the lipid hydroperoxide (LH) levels, protein carbonyl concentrations and DNA damage in cardiac tissue of rats exposed to tobacco smoke.

METHODS

Male Wistar rats were divided into two groups: group C (control, n = 14) composed of animals not exposed to cigarette smoke; group ETS (exposed to tobacco smoke, n = 14) composed by animals exposed to cigarette smoke. The animals were exposed to 2 month of ETS and morphological, biochemical and functional analyses were performed.

RESULTS

Cardiac cotinine levels were elevated in the ETS group. In addition, the myocyte cross-sectional area was higher in the ETS group. (C = 266.6 ± 23.2 μm2 and ETS = 347.5 ± 15.1 μm2, p <  0.001). Cardiac LH was higher in the ETS group than in group C (C = 196.4 ± 51.5 nmol/g and ETS = 331.9 ± 52.9 nmol/g, p <  0.001). However, there were no between-group differences in cardiac protein carbonyl concentration or DNA damage.

CONCLUSIONS

Therefore, our results suggest that, in this model, lipid damage is a good marker of oxidative damage during the cardiac remodeling process induced by 2 months of exposure to tobacco smoke.

Childhood and adult exposure to secondhand tobacco smoke and cardiac structure and function: results from Echo-SOL

Objective

To describe the relationship of household secondhand smoke (SHS) exposure and cardiac structure and function.

Methods

Participants (n=1069; 68 % female; age 45–74 years) without history of tobacco use, coronary artery disease or severe valvular disease were included. Past childhood (starting at age <13 years), adolescent/adult and current exposure to household SHS was assessed. Survey linear regression analyses were used to model the relationship of SHS exposure and echocardiographic measures of cardiac structure and function, adjusting for covariates (age, sex, study site, alcohol use, physical activity and education).

Results

SHS exposure in childhood only was associated with reduced E/A velocity ratio (β=−0.06 (SE 0.02), p=0.008). SHS exposure in adolescence/adult only was associated with increased left ventricular ejection fraction (LVEF) (1.2 (0.6), p=0.04), left atrial volume index (1.7 (0.8), p=0.04) and decreased isovolumic relaxation time (−0.003 (0.002), p=0.03). SHS exposure in childhood and adolescence/adult was associated with worse left ventricular global longitudinal strain (LVGLS) (two-chamber) (0.8 (0.4), p= 0.049). Compared with individuals who do not live with a tobacco smoker, individuals who currently live with at least one tobacco smoker had reduced LVEF (−1.4 (0.6), p=0.02), LVGLS (average) (0.9 (0.40), p=0.03), medial E′ velocity (−0.5 (0.2), p=0.01), E/A ratio (−0.09 (0.03), p=0.003) and right ventricular fractional area change (−0.02 (0.01), p=0.01) with increased isovolumic relaxation time (0.006 (0.003), p=0.04).

Conclusions

Past and current household exposure to SHS was associated with abnormalities in cardiac systolic and diastolic function. Reducing household SHS exposure may be an opportunity for cardiac dysfunction prevention to reduce the risk of future clinical heart failure.

Spondias mombin supplementation attenuated cardiac remodelling process induced by tobacco smoke

The objective of this study was to investigate the influence of Spondias mombin (SM) supplementation on the cardiac remodelling process induced by exposure to tobacco smoke (ETS) in rats. Male Wistar rats were divided into 4 groups: group C (control, n = 20) comprised animals not exposed to cigarette smoke and received standard chow; group ETS (n = 20) comprised animals exposed to cigarette smoke and received standard chow; group ETS100 (n = 20) received standard chow supplemented with 100 mg/kg body weight/d of SM; and group ETS250 (n = 20) received standard chow supplemented with 250 mg/kg body weight/d of SM. The observation period was 2 months. The ETS animals had higher values of left cardiac chamber diameters and of left ventricular mass index. SM supplementation attenuated these changes. In addition, the myocyte cross‐sectional area (CSA) was lower in group C compared with the ETS groups; however, the ETS250 group had lower values of CSA compared with the ETS group. The ETS group also showed higher cardiac levels of lipid hydroperoxide (LH) compared with group C; and, groups ETS100 and ETS250 had lower concentrations of LH compared with the ETS group. Regarding energy metabolism, SM supplementation decreased glycolysis and increased the β‐oxidation and the oxidative phosphorylation. There were no differences in the expression of Nrf‐2, SIRT‐1, NF‐κB, interferon‐gamma and interleukin 10. In conclusion, our results suggest that ETS induced the cardiac remodelling process. In addition, SM supplementation attenuated this process, along with oxidative stress reduction and energy metabolism modulation.

Functional, Cellular, and Molecular Remodeling of the Heart under Influence of Oxidative Cigarette Tobacco Smoke

Passive and active chronic cigarette smoking (CS) remains an international epidemic and a key risk factor for cardiovascular disease (CVD) development. CS-induced cardiac damage is divided into two major and interchangeable mechanisms: (1) direct adverse effects on the myocardium causing smoking cardiomyopathy and (2) indirect effects on the myocardium by fueling comorbidities such as atherosclerotic syndromes and hypertension that eventually damage and remodel the heart. To date, our understanding of cardiac remodeling following acute and chronic smoking exposure is not well elucidated. This manuscript presents for the first time the RIMD (oxidative stress (R), inflammation (I), metabolic impairment (M), and cell death (D)) detrimental cycle concept as a major player in CS-induced CVD risks and direct cardiac injury. Breakthroughs and latest findings in the field with respect to structural, functional, cellular, and molecular cardiac remodeling following chronic smoking exposure are summarized. This review also touches the genetics/epigenetics of smoking as well as the smoker's paradox and highlights the most currently prominent pharmacological venues to mitigate CS-induced adverse cardiac remodeling.

Green tea (Cammellia sinensis) attenuates ventricular remodeling after experimental myocardial infarction

BACKGROUND

Considering the high morbidity and mortality after myocardial infarction (MI), the study of compounds with potential benefits for cardiac remodeling is reasonable. Green tea (GT) (Cammellia sinensis) is the most consumed beverage in the world. The potential action mechanisms of GT include anti-inflammatory, anti-apoptotic, antioxidant, and lipid-lowering properties.

OBJECTIVE

This study analyzed the effects of GT on cardiac remodeling following coronary occlusion in rats.

METHODS

Male Wistar rats were divided into four groups: control (C), control green tea (GT), myocardial infarction (MI), and myocardial infarction and green tea (MI-GT). GT and MI-GT were fed with standard chow with 0.25% Polyphenon 60 (Sigma-Aldrich Canada, Oakville, ON, Canada). After 3months of observation, echocardiographic and isolated heart study, oxidative stress, energy metabolism, serum lipids, extracellular matrix, and apoptosis were evaluated.

RESULTS

GT reduced cardiac hypertrophy and improved systolic and diastolic dysfunction. Concerning oxidative stress, GT reduced protein carbonyl, increased Nrf-2, and restored antioxidant enzyme activity to the control pattern. Energy metabolism was affected by MI that presented with lower fatty acid oxidation and accumulation of triacylglycerol, increased serum lipids, impairment of the citric acid cycle, and oxidative phosphorylation. GT stimulated the glucose pathway and mitochondrial function after MI by increasing pyruvate dehydrogenase, Complex I, ATP synthase, and glycogen storage. In addition, MI changed the extracellular matrix including MMP-2 and TIMP-1 activity and increased apoptosis by 3-caspase, all of which were attenuated by GT.

CONCLUSION

GT attenuated cardiac remodeling after MI, associated with improvement in systolic and diastolic dysfunction. Oxidative stress, energy metabolism, apoptosis, and extracellular matrix alterations are all potential mechanisms by which GT may take part.

Pentoxifylline Attenuates Cardiac Remodeling Induced by Tobacco Smoke Exposure

Background

Tobacco smoke exposure is an important risk factor for cardiac remodeling. Under this condition, inflammation, oxidative stress, energy metabolism abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative properties.

Objective

The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking.

Methods

Wistar rats were distributed in four groups: Control (C), Pentoxifylline (PX), Tobacco Smoke (TS), and PX-TS. After two months, echocardiography, invasive blood pressure measurement, biochemical, and histological studies were performed. The groups were compared by two-way ANOVA with a significance level of 5%.

Results

TS increased left atrium diameter and area, which was attenuated by PX. In the isolated heart study, TS lowered the positive derivate (+dp/dt), and this was attenuated by PX. The antioxidants enzyme superoxide dismutase and glutathione peroxidase were decreased in the TS group; PX recovered these activities. TS increased lactate dehydrogenase (LDH) and decreased 3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA) and citrate synthase (CS). PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased IL-10, ICAM-1, and caspase-3. PX did not influence these variables.

Conclusion

TS induced cardiac remodeling, associated with increased inflammation, oxidative stress, apoptosis, and changed energy metabolism. PX attenuated cardiac remodeling by reducing oxidative stress and improving cardiac bioenergetics, but did not act upon cardiac cytokines and apoptosis.

Change in left ventricular systolic function in patients with ST elevation myocardial infarction: Evidence for smoker's paradox or pseudo-paradox?

Background

The ‘smoker's paradox’ refers to the observation of favorable prognosis in current smokers following an acute ST elevation myocardial infarction (STEMI) in the era of fibrinolysis, however, several STEMI studies have demonstrated conflicting results in patients undergoing primary percutaneous coronary intervention (p-PCI).

Objective

Aim of the current study was to evaluate the impact of cigarette smoking on left ventricular function in STEMI patients undergoing p-PCI.

Methods

Our population is represented by 74 first-time anterior STEMI patients undergoing p-PCI, 37 of whom were smokers. We assessed left ventricular function by left ventricular ejection fraction (LVEF) on the second day after admission and at 3-month follow-up. Early predictors of adverse left ventricular remodelling after STEMI treated by p-PCI were examined.

Results

Basal demographics and comorbidities were similar between groups. Although the LVEF during the early phase was higher in smokers compared to non-smokers (44.95 ± 7.93% vs. 40.32 ± 7.28%; p = 0.011); it worsened in smokers at follow-up (mean decrease in LVEF: −2.70 ± 5.95%), whereas it improved in non-smokers (mean recovery of LVEF: +2.97 ± 8.45%). In univariate analysis, diabetes mellitus, peak troponin I, current smoking, and lower TIMI flow grade after p-PCI, pain-to-door time and door-to-balloon times were predictors of adverse left ventricular remodelling. After multivariate logistic regression analysis, smoking at admission, lower TIMI flow grade after p-PCI, the pain-to-door time and door-to-balloon times remained independent predictors of deterioration in LVEF.

Conclusion

True or persistent ‘smoker's paradox’ does not appear to be relevant among STEMI patients undergoing p-PCI. The ‘smoker's paradox’ is in fact a pseudo-paradox. Further studies with larger numbers may be warranted.

Cardiac Remodeling: Concepts, Clinical Impact, Pathophysiological Mechanisms and Pharmacologic Treatment

Cardiac remodeling is defined as a group of molecular, cellular and interstitial changes that manifest clinically as changes in size, mass, geometry and function of the heart after injury. The process results in poor prognosis because of its association with ventricular dysfunction and malignant arrhythmias. Here, we discuss the concepts and clinical implications of cardiac remodeling, and the pathophysiological role of different factors, including cell death, energy metabolism, oxidative stress, inflammation, collagen, contractile proteins, calcium transport, geometry and neurohormonal activation. Finally, the article describes the pharmacological treatment of cardiac remodeling, which can be divided into three different stages of strategies: consolidated, promising and potential strategies.