Model studies linking carbon monoxide and/or nicotine to arteriosclerosis and cardiovascular disease

Interrelation of Cadmium, Smoking, and Cardiovascular Disease (from the National Health and Nutrition Examination Survey)

Cadmium biomarker levels are associated with both cigarette smoking and cardiovascular disease. In this cross-sectional survey, we explore whether the association between cadmium and cardiovascular disease differs between cigarette smoking states. A cross-sectional analysis using the National Health and Nutrition Examination Survey in 2003 to 2012 was performed accounting for the nationally representative complex sampling design. All participants 45 to 79 years old with blood and urinary cadmium levels were included (n = 12,511). We explored the inter-relationships of blood and urine cadmium levels with cigarette smoking and a composite cardiovascular outcome that included self-reported myocardial infarction or stroke or both. We used multivariable logistic regressing models to further adjust for age, income, gender, hypercholesterolemia, body mass index, diabetes, smoking intensity, and time period of smoking cessation. Of the 12,511 participants, 1,330 (8.5%) had previous myocardial infarction or stroke or both. The crude prevalence ratio (PR) comparing those in the lowest tertile of blood cadmium with those in the highest tertile for the composite outcome was 1.73 (95% confidence interval [CI] 1.49 to 2.01). After adjustment for age, gender, income, self-reported diabetes, self-reported hypercholesterolemia, body mass index, and smoking status, the PR was 1.54 (95% CI 1.30 to 1.84). The adjusted PRs for each smoking subgroup were 1.54 (95% CI 1.09 to 2.18) for never-smokers, 1.57 (95% CI 1.11 to 2.23) for current smokers, and 1.31 (95% CI 0.96 to 1.78) for former smokers. These descriptive data from a nationally representative sample suggest that cadmium is related to cardiovascular outcomes even after adjustment for smoking status.

Smoking and smoking cessation -- the relationship between cardiovascular disease and lipoprotein metabolism: a review

Cigarette smoking is generally accepted as the most preventable cause of death in the United States today. Individuals who smoke experience a wide range of physiologic side effects that increase the risk of cardiovascular disease (CVD), including insulin resistance, elevated catecholamine levels which contribute to an elevated heart rate and blood pressure, and hypercholesterolemia. The link between hypercholesterolemia and cardiovascular disease has been extensively researched and is undeniable. What is more, this link is strengthened in smokers as cigarette smoking is known to increase total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL), while acting to decrease the cardio-protective high-density lipoprotein (HDL). Alterations in the enzymes that control lipid transport may be a key underlying mechanism contributing to these health destroying effects. This review examines the current literature related to: (1) smoking, lipoproteins, and lipid-related enzymes; (2) the impact of nicotine, carbon monoxide and free radicals on physiologic parameters related to health; and (3) metabolic issues involving smoking cessation and nicotine replacement therapy.

Influence of smoking during pregnancy on haemostasis in healthy full term neonates

BACKGROUND

Clinical and experimental researches have linked smoking to disturbances of coagulation and fibrinolysis. Several potential mechanisms are incriminated involving inflammation, fibrinogen synthesis and clotting factors. Based on the fact that the majority of tobacco components cross the placental barrier, the objective of our current study is to investigate the influence of smoking during pregnancy on neonatal haemostasis.

STUDY DESIGN

The study was based on a comparative evaluation of coagulation and fibronolysis between healthy full term infants of women who smoked during pregnancy and a control group. Subjects consisted of 39 newborns of smoking and 43 newborns of nonsmoking mothers. Blood samples were obtained shortly after birth and before the administration of vitamin K. Investigation included: PT, INR, aPTT, fibrinogen, coagulation factors II, V, VII, VIII, IX, X, XI, XII, vWillebrand (vWF), protein C and S, APCr, anti-thrombin (AT), t-PA and PAI-1. The independent t- test was used to compare the differences between the values of coagulation and fibrinolytic parameters at the p<0.05 level.

RESULTS

We discovered a statistically significant decrease in factor II and protein S levels and an elevation in t-PA and factor VIII concentrations in newborns of smoking mothers, without clinical manifestations of altered haemostasis. There were no significant differentiations in other coagulation or fibrinolytic parameters.

CONCLUSION

The alteration in factor II, protein S, t-PA and factor VIII in neonates exposed in utero to tobacco smoke is not accompanied by loss in the balance between coagulation and fibrinolytic pathways.

The pathophysiology of cigarette smoking and cardiovascular disease: an update

Cigarette smoking (CS) continues to be a major health hazard, and it contributes significantly to cardiovascular morbidity and mortality. Cigarette smoking impacts all phases of atherosclerosis from endothelial dysfunction to acute clinical events, the latter being largely thrombotic. Both active and passive (environmental) cigarette smoke exposure predispose to cardiovascular events. Whether there is a distinct direct dose-dependent correlation between cigarette smoke exposure and risk is debatable, as some recent experimental clinical studies have shown a non-linear relation to cigarette smoke exposure. The exact toxic components of cigarette smoke and the mechanisms involved in CS-related cardiovascular dysfunction are largely unknown, but CS increases inflammation, thrombosis, and oxidation of low-density lipoprotein cholesterol. Recent experimental and clinical data support the hypothesis that cigarette smoke exposure increases oxidative stress as a potential mechanism for initiating cardiovascular dysfunction.

How smoking affects blood pressure

The addictive effects of smoking are only partly known, but it is likely that hemodynamic effects of tobacco smoking may contribute to the habituation. It has since long been known that blood pressure and heart rate increase during smoking. These effects are specifically associated with nicotine while the other components of which more than a thousand have been isolated seem to be of minor importance. The rise in blood pressure is due both to an increase in cardiac output and total peripheral vascular resistance. The blood pressure rise appears immediately and occurs before any increase in circulating catecholamines. In hypertensive patients the blood pressure lowering effect of beta-blockers may be partly abolished by tobacco smoking whereas alpha-receptor blockers seem to maintain the antihypertensive efficacy in smokers. It is a paradox that while smoking acutely increases blood pressure, a slightly lower blood pressure level has been found among smokers than nonsmokers in larger epidemiological studies. Because blood pressure may increase after cessation of smoking, a smoke quitting program should not postpone initiation of antihypertensive treatment in patients otherwise in need of such treatment.

Successful heart transplantation from a victim of carbon monoxide poisoning

Heart transplantation has become a highly successful, life-saving treatment for a number of otherwise fatal heart diseases. A major limiting factor in the growth of transplantation surgery has been the relative lack of suitable donor organs, and the appropriate criteria for selection of donor organs have been a topic of significant interest. Despite relatively favorable survival rates in the few patients who have received organs from victims of many types of poisonings and drug overdoses, patients dying of toxicologic causes are not usually considered suitable organ donors. Some centers routinely reject such individuals. Criteria for donor selection continue to be vague, unclear, or nonexistent in regard to organ transplantation from victims of all types of poisoning and toxic exposures. Carbon monoxide (CO) is a ubiquitous poison, and although victims of CO poisoning have occasionally served as suitable organ donors, heart transplantation in this scenario is still a very rare event. We describe the successful transplantation of the heart from a CO poisoning victim--to our knowledge, only the third such transplantation. Because the emergency department is a critical site for organ procurement, emergency physicians must be aware that patients dying of CO exposure may be acceptable organ donors.

Responses of vascular smooth muscle cells to toxic insult: cellular and molecular perspectives for environmental toxicants

Over the past several decades emphasis has been given to the elucidation of mechanisms involved in the onset and progression of cardiovascular disorders. Stroke, hypertension, and atherosclerosis continue to rank as primary causes of death in the western world. In the case of atherosclerosis, the preferential localization of atheroma to large- and medium-sized blood vessels and the sequence of events leading to plaque development have been well defined. Damage to luminal endothelial and/or medial smooth muscle cells, migration of inflammatory cells, diffusion or local delivery of mediators within the vessel wall, proliferation of vascular smooth muscle cells, and cellular accumulation of lipids are now recognized as hallmarks of the pathologic process. Although these events have been established with a fair degree of certainty, the mechanisms responsible for initiation of the atherosclerotic process are not yet completely understood. Environmental chemicals have come under increasing scrutiny as evidence continues to accumulate suggesting that toxic insult plays an important role in the initiation and/or progression of atherosclerotic disorders. This review focuses on various aspects of xenobiotic-induced vascular injury with emphasis on the toxic effects of allylamine and benzo[a]pyrene in smooth muscle cells, the primary cellular component of atherosclerotic lesions. Both of these chemicals modulate growth and differentiation programs in aortic smooth muscle cells and have been implicated in the development of atherosclerotic-like lesions in laboratory animals. The major findings from recent studies examining the cellular and molecular basis of toxicant-induced phenotypic modulation of vascular smooth muscle cells to a proliferative state and the role of oxidative metabolism, phospholipid turnover, protein kinase C, ras-related signal transduction, and matrix interactions in the vasculotoxic response to allylamine and benzo[a]pyrene are discussed.

Smoking and apolipoproteins in adolescents. The Niño Jesus Group

The relation between smoking and blood lipids and apolipoproteins (A1,B100) were studied in a group of 1024 12- to 18-year-old school children in the Comunidad de Madrid. The percentage of smokers was 19% (17% for girls and 21% for boys). The average consumption of cigarettes per day was 7.83 +/- 5.06 in boys and 6.04 +/- 3.49 in girls (p less than 0.05). As compared with male nonsmokers, male smokers showed a higher mean level of low-density lipoprotein (LDL) cholesterol (112 versus 100 mg/dL, p less than 0.05), a higher LDL cholesterol to HDL-cholesterol ratio (2.27 versus 1.94, p less than 0.001), a higher mean level of apolipoprotein B100 (59 versus 53 mg/dL, p less than 0.05), and a higher apolipoprotein B100 to apolipoprotein A1 ratio (0.45 versus 0.40, p less than 0.01). Female smokers tended to show the same results, although significant differences were only found for LDL cholesterol to HDL cholesterol ratio and apolipoprotein B100 to apolipoprotein A1 ratio (1.8 versus 1.59 and 0.41 versus 0.38 respectively, both p less than 0.05). This work provides new data about the effects of smoking on apolipoproteins in adolescents and emphasizes on the need for preventive programs.

The effect of maternal smoke exposure on the ultrastructure of fetal peripheral blood vessels in the mouse

Ultrastructural changes have been found in umbilical blood vessels, placental blood vessels, and peripheral blood vessels of human fetuses whose mothers smoked during pregnancy. This study was undertaken to determine if similar changes could be found in peripheral blood vessels of mice fetuses whose mothers were exposed to cigarette smoke during pregnancy. Breeding mice of the C57BL/KsJ strain were placed in a smoking box similar to that described by Younoszai and exposed to cigarette smoke intermittently. This produces carbon monoxide levels in the adult mice similar to that found in human adults smoking one pack of cigarettes per day. Similarly caged mice of the same strain were used as controls. The female mice were not removed from their cage from pre-conception time until after delivery. Upon delivery each pup was sacrificed via neck fracture and the entire pup was immersed in a solution of 2.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.3. While still under solution, the rear leg muscles were dissected free, sliced, and immersed in the same preservative for four to five hours. They were then placed in fresh 2.5% glutaraldehyde mixture overnight. The tissues were post-fixed in osmium ferrocyanide and en-block stained with uranyl acetate in a graded series of alcohol. The tissues were infiltrated with and embedded in Spurr. Sections were taken via an ultramicrotome and post-stained with uranyl acetate and lead citrate. The sections were examined in a Philips 201 electron microscope at 60 KV. In the peripheral vessels of the fetuses from smoke-exposed mothers, endothelial blebbing (both surface-type and vacuole-type) was seen.(ABSTRACT TRUNCATED AT 250 WORDS)

The association of smoking with cardiomyopathy

We investigated the possibility that smoking has an association with ventricular wall-motion abnormalities that is independent of its known association with coronary occlusion. We studied 4763 men between the ages of 35 and 74 who had diagnostic coronary angiography and ventriculography. We considered three kinds of wall-motion abnormalities: hypokinesis in one to four ventricular segments, hypokinesis in five to six ventricular segments (diffuse hypokinesis), and akinetic or dyskinetic wall motion in at least one segment. Among men younger than 55, the relative risk of diffuse hypokinesis was 2.78 (1.1 to 6.99) for heavy smokers as compared with nonsmokers. Adjusting for the degree of coronary occlusion or eliminating subjects with a history of myocardial infarction did not change this relative risk. Among men who were 55 or older the relative risk (odds ratio for heavy smokers as compared with nonsmokers) was not significant (0.55 to 2.28). Regardless of age the relative risk of akinesis or dyskinesis, adjusted for coronary stenosis, was significant: 1.84 (1.28 to 2.65) for men under 55 and 1.57 (1.12 to 2.19) for men 55 or older. These results suggest that smoking is related to both cardiomyopathy and transmural myocardial infarction and that the relationships are largely separate from the association of smoking with coronary stenosis.

Cigarette smoking as a risk for cardiovascular disease III: Biochemical effects with higher nicotine yield cigarettes

Subjects who smoked a medium range nicotine yield cigarette were given a higher nicotine yield cigarette (an increase of 0.34 mg nicotine) to smoke ad libitum for two weeks. Plasma nicotine, cotinine, thiocyanate and blood carboxyhemoglobin levels were determined as well as various physiological parameters including heart rate and blood pressure. Increases in plasma nicotine were most directly correlated to heart rate when smokers were first challenged with a higher nicotine yield cigarette (r = 0.85); less directly correlated after a two-week acclimatization period (r = 0.42) and poorly related to their customary product (r = 0.23). Interestingly, it was noted that subjects did not compensate for higher nicotine yield by smoking fewer cigarettes per day when incremental nicotine changes were realistic. They did, however, show higher plasma nicotine, thiocyanate and an upward trend in plasma cotinine with the stronger cigarettes. These increases in cigarette constituents present in plasma, coupled with increasing correlation of heart rate and nicotine uptake, lead us to suggest that uptitration of smokers might cause them to establish new baseline levels. These findings have important health implications in light of recent suggestions to increase the nicotine yet decrease the tar of cigarettes in an attempt to overcome smoker compensation phenomena observed with low yield products.