Effect of cigarette smoking on nitric oxide, structural, and mechanical properties of mouse arteries

Exploring the Molecular Link Between Diabetes and Erectile Dysfunction Through Single-Cell Transcriptome Analysis

Erectile dysfunction (ED) is a pathophysiological condition in which the patients cannot achieve an erection during sexual activity, and it is often overlooked yet prevalent among diabetic men, globally affecting approximately 35-75% of diabetic individuals. The precise mechanisms through which diabetes contributes to ED remain elusive, but the existing literature suggests the potential involvement of nerve and vascular damage that affects the penile supply. In the present review, we reanalyze the existing human single-cell transcriptomic data from patients having diabetes mellitus-associated ED with normal erections. The analysis validates the expression of genes associated with antioxidative pathways, growth factors, adipokines, angiogenesis, vascular functions, penile erection, sexual function, and inflammation in diverse cell types from healthy individuals and those with ED. Our transcriptomic analysis reveals alterations in the expression of adiponectin receptors in the pathogenesis of ED compared to their counterparts in healthy subjects. This comprehensive review sheds light on the molecular underpinnings of ED in the context of diabetes, providing an in-depth understanding of the biological and cellular alterations involved and paving the way for possible targeted therapeutic discoveries in the field of diabetes-associated male infertility.

Effect of cigarette smoking on smoking biomarkers, blood pressure and blood lipid levels among Sri Lankan male smokers

Study purpose

The aim of this study was to determine the fractional exhaled nitric oxide (FeNO) levels, exhaled breath carbon monoxide (eCO) levels, blood pressure, blood lipid levels between smokers and non-smokers and to determine the association of smoking intensity with the above parameters.

Methods

This descriptive study was conducted in selected periurban areas of the Colombo District, Sri Lanka. Adult male current tobacco smokers (n=360), aged between 21 and 60 years were studied and compared with anthropometrically matched male non-smokers (n=180). Data were collected by interviewer-administered questionnaire, clinical assessment and measurement of FeNO by FENO monitor and eCO bySmokerlyser.

Results

Smokers had significantly lower mean FeNO levels and higher mean eCO values compared with non-smokers. Presentation of palpitations was higher among the smokers and a significantly positive correlation was identified between palpitations and eCO levels. There was a significantly positive correlation between the systolic blood pressure of smokers with the duration of smoking (DS), Brinkman Index (BI), Body Mass Index (BMI) and there was a significantly negative correlation with FeNO levels. The mean arterial pressure was positively correlated with the DS, BI and BMI. There was a significantly negative correlation between FeNO and the number of cigarettes smoked per day, DS and BI of smokers. Significantly higher total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), very LDL-C, TC: HDL ratio and low high density lipoprotein cholesterol (HDL-C) level was observed among smokers compared with the non-smokers.

Conclusions

Tobacco smoking was found to impact blood pressure and serum lipid levels thus enhancing the cardiovascular risk among smokers. The levels of eCO and FeNO are useful biomarkers for determining the intensity of smoking. The results indicate the necessity for urgent measures to stop cigarette smoking in Sri Lanka.

Erectile Dysfunction in Men with Chronic Obstructive Pulmonary Disease

Erectile dysfunction (ED) seems to be a widespread sexual issue in men affected by chronic obstructive pulmonary disease (COPD). Multiple causes appear to be involved such as hormonal imbalance, smoking habit, chronic inflammation, endothelial dysfunction, chronic hypoxia, psychiatric disorders (depression and anxiety), and medications. ED can have a significant impact on COPD men and consequently on their quality of life, which is usually already compromised. Given this situation, however, pneumologists usually do not properly care for the sexuality of COPD patients especially because men can be reluctant to talk about their intimate issues. The aim of this narrative review is to briefly summarize the evidence emerging from literature and to provide a wide point of view about sexual dysfunction in COPD men.

Structural and functional remodeling of the female Apoe-/- mouse aorta due to chronic cigarette smoke exposure

Despite a decline in popularity over the past several decades, cigarette smoking remains a leading cause of cardiovascular morbidity and mortality. Yet, the effects of cigarette smoking on vascular structure and function are largely unknown. To evaluate changes in the mechanical properties of the aorta that occur with chronic smoking, we exposed female apolipoprotein E-deficient mice to mainstream cigarette smoke daily for 24 wk, with room air as control. By the time of euthanasia, cigarette-exposed mice had lower body mass but experienced larger systolic/diastolic blood pressure when compared with controls. Smoking was associated with significant wall thickening, reduced axial stretch, and circumferential material softening of the aorta. Although this contributed to maintaining intrinsic tissue stiffness at control levels despite larger pressure loads, the structural stiffness became significantly larger. Furthermore, the aorta from cigarette-exposed mice exhibited decreased ability to store elastic energy and augment diastolic blood flow. Histological analysis revealed a region-dependent increase in the cross-sectional area due to smoking. Increased smooth muscle and extracellular matrix content led to medial thickening in the ascending aorta, whereas collagen deposition increased the thickness of the descending thoracic and abdominal aorta. Atherosclerotic lesions were larger in exposed vessels and featured a necrotic core overlaid by a thinned fibrous cap and macrophage infiltration, consistent with a vulnerable phenotype. Collectively, our data indicate that cigarette smoking decreases the mechanical functionality of the aorta, inflicts morphometric alterations to distinct segments of the aorta, and accelerates the progression of atherosclerosis.NEW & NOTEWORTHY We studied the effects of chronic cigarette smoking on the structure and function of the aorta in a mouse model of nose-only aerosol inhalation. Our data indicated that exposure to cigarette smoke impairs vascular function by reducing the ability of the aorta to store elastic energy and by decreasing aortic distensibility. Combined with a more vulnerable atherosclerotic phenotype, these findings reveal the biomechanical mechanisms that support the development of cardiovascular disease due to cigarette smoking.

Impact of whole-body versus nose-only inhalation exposure systems on systemic, respiratory, and cardiovascular endpoints in a 2-month cigarette smoke exposure study in the ApoE-/- mouse model

Cigarette smoking is one major modifiable risk factor in the development and progression of chronic obstructive pulmonary disease and cardiovascular disease. To characterize and compare cigarette smoke (CS)-induced disease endpoints after exposure in either whole-body (WB) or nose-only (NO) exposure systems, we exposed apolipoprotein E-deficient mice to filtered air (Sham) or to the same total particulate matter (TPM) concentration of mainstream smoke from 3R4F reference cigarettes in NO or WB exposure chambers (EC) for 2 months. At matching TPM concentrations, we observed similar concentrations of carbon monoxide, acetaldehyde, and acrolein, but higher concentrations of nicotine and formaldehyde in NOEC than in WBEC. In both exposure systems, CS exposure led to the expected adaptive changes in nasal epithelia, altered lung function, lung inflammation, and pronounced changes in the nasal epithelial transcriptome and lung proteome. Exposure in the NOEC caused generally more severe histopathological changes in the nasal epithelia and a higher stress response as indicated by body weight decrease and lower blood lymphocyte counts compared with WB exposed mice. Erythropoiesis, and increases in total plasma triglyceride levels and atherosclerotic plaque area were observed only in CS-exposed mice in the WBEC group but not in the NOEC group. Although the composition of CS in the breathing zone is not completely comparable in the two exposure systems, the CS-induced respiratory disease endpoints were largely confirmed in both systems, with a higher magnitude of severity after NO exposure. CS-accelerated atherosclerosis and other pro-atherosclerotic factors were only significant in WBEC.

Chronic cigarette smoke exposure triggers a vicious cycle of leukocyte and endothelial-mediated oxidant stress that results in vascular dysfunction

Although there is a strong association between cigarette smoking exposure (CSE) and vascular endothelial dysfunction (VED), the underlying mechanisms by which CSE triggers VED remain unclear. Therefore, studies were performed to define these mechanisms using a chronic mouse model of cigarette smoking (CS)-induced cardiovascular disease mirroring that in humans. C57BL/6 male mice were subjected to CSE for up to 48 wk. CSE impaired acetylcholine (ACh)-induced relaxation of aortic and mesenteric segments and triggered hypertension, with mean arterial blood pressure at 32 and 48 wk of exposure of 122 ± 6 and 135 ± 5 mmHg compared with 99 ± 4 and 102 ± 6 mmHg, respectively, in air-exposed mice. CSE led to monocyte activation with superoxide generation in blood exiting the pulmonary circulation. Macrophage infiltration with concomitant increase in NADPH oxidase subunits p22^phox and gp91^phox was seen in aortas of CS-exposed mice at 16 wk, with further increase out to 48 wk. Associated with this, increased superoxide production was detected that decreased with Nox inhibition. Tetrahydrobiopterin was progressively depleted in CS-exposed mice but not in air-exposed controls, resulting in endothelial nitric oxide synthase (eNOS) uncoupling and secondary superoxide generation. CSE led to a time-dependent decrease in eNOS and Akt expression and phosphorylation. Overall, CSE induces vascular monocyte infiltration with increased NADPH oxidase-mediated reactive oxygen species generation and depletes the eNOS cofactor tetrahydrobiopterin, uncoupling eNOS and triggering a vicious cycle of oxidative stress with VED and hypertension. Our study provides important insights toward understanding the process by which smoking contributes to the genesis of cardiovascular disease and identifies biomarkers predictive of disease.NEW & NOTEWORTHY In a chronic model of smoking-induced cardiovascular disease, we define underlying mechanisms of smoking-induced vascular endothelial dysfunction (VED). Smoking exposure triggered VED and hypertension and led to vascular macrophage infiltration with concomitant increase in superoxide and NADPH oxidase levels as early as 16 wk of exposure. This oxidative stress was accompanied by tetrahydrobiopterin depletion, resulting in endothelial nitric oxide synthase uncoupling with further superoxide generation triggering a vicious cycle of oxidative stress and VED.

Pharmacology and perspectives in erectile dysfunction in man

Penile erection is a perfect example of microcirculation modulated by psychological factors and hormonal status. It is the result of a complex neurovascular process that involves the integrative synchronized action of vascular endothelium; smooth muscle; and psychological, neuronal, and hormonal systems. Therefore, the fine coordination of these events is essential to maintain penile flaccidity or allow erection; an alteration of these events leads to erectile dysfunction (ED). ED is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity. A great boost to this research field was given by commercialization of phosphodiesterase-5 (PDE5) inhibitors. Indeed, following the discovery of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost, and many preclinical and clinical papers have been published in the last 10 years. This review is structured to provide an overview of the mediators and peripheral mechanism(s) involved in penile function in men, the drugs used in therapy, and the future prospective in the management of ED. Indeed, 30% of patients affected by ED are classified as "nonresponders," and there is still an unmet need for therapeutic alternatives. A flowchart suggesting the guidelines for ED evaluation and the ED pharmacological treatment is also provided.

Circulating markers of nitric oxide homeostasis and cardiometabolic diseases: insights from population-based studies

Emerging data suggest that impaired nitric oxide (NO) homeostasis has a key role in development of cardiometabolic disorders. The association between circulating levels of NO metabolites, i.e. nitrate and nitrite (NOx), and risk of chronic diseases has not yet been fully clarified. This work aims to address epidemiologic aspects of NO metabolism and discusses different physiologic and pathophysiologic conditions influencing circulating NOx. Further, cross-sectional associations of serum NOx with metabolic disorders are described and along the way, potential short-term and long-term power of serum NOx for predicting cardiometabolic outcomes are reviewed. Results from population-based studies show that circulating NOx is affected by aging, smoking habits, pregnancy, menopause status, thyroid hormones, and various pathologic conditions including type 2 diabetes, insulin resistance, hypertension, and renal dysfunction. Lifestyle factors, especially dietary habits, but also smoking habits and the degree of physical activity influence NO homeostasis and the circulating levels of NOx. Elevated serum NOx, due to increased iNOS activity, is associated with increased incidence of metabolic syndrome, different obesity phenotypes, and cardiovascular events.

Relation of smoking and endothelial dysfunction markers in systemic hypertension

Aim. Assessment of the markers levels of endothelial dysfunction (ED): stable metabolites of nitric oxide (NOx), endothelin-1 (E1), homocysteine (HC), von Willebrand factor (vWF) and tissue plasminogen activator (tPA) in blood plasma of smoker and nonsmoker patients with arterial hypertension (AH) of low and moderate risk, not taking antihypertension therapy regularly.

Material and methods. Totally, 124 AH patients included, 45 males and 79 females, mean age 51,4±6,5 y.o., mean AH duration 7,9±7,3 y. Controls included 35 healthy volunteers (20 males, 15 females). Concentration of NOx in plasma was measured with spectrophotometry, and of vWF, HC, E1 and tPA — with immune enzyme assay.

Results. To evaluate the relation of smoking and ED markers levels, AH patients and controls were selected to subgroups according to smoking status: smoker (35,5%) and non-smoker (64,5%) AH patients; smoker (38%) and non-smoker (62%) controls. In smoker AH patients comparing to non-smoking there were significantly higher concentrations of NOx — 48,2±18,8 mcM/L and 40,3±21,2 mcM/L, respectively (р<0,05), E1 — 1,2±0,16 and 0,6±0,2 fM/L, resp. (р<0,05), HC — 25,7±6,04 and 16,2±6,5 mcM/L, resp. (р<0,05), vWF — 1,39±0,7 and 1,1±0,6 mg/dL, resp (р<0,05) and tPA — 13,05±6,2 and 8,5±6,2 mcM/L, resp. (р<0,05). There was correlation in the AH group, of NOx concentration and smoking (r=0,46, р<0,05), and tobacco smoking duration (r=0,83, р<0,05). Also, there were positive correlations of HC and smoking (r=0,4, p<0,05). In control group smokers had higher HC — 20,7±5,3 and 17,2±4,7 mcM/L, resp. (р<0,05), vWF — 1,3±0,8 and 0,8±0,6 mg/dL, resp. (р<0,05) and tPA — 11,1±6,5 and 6,6±5,2 mcM/L, resp. (р<0,05). There were no significant changes in NOx and E1.

Conclusion. In smokers of both AH and control groups the levels of HC, vWF and tPA were significantly higher in comparison with nonsmokers. In smoker AH patients the mean concentrations of NOx and E1 are higher than in non-smoker patients. Levels of ED are related with not only the fact of smoking itself (р<0,05), but smoking duration (р<0,05).

17-α Hydroxyprogesterone Caproate for the Prevention of Recurrent Preterm Birth: One Size May Not Fit All

Spontaneous preterm birth is a syndrome with many causes and thus unresponsive to a single intervention. It logically follows that patients with a prior spontaneous preterm birth are a heterogeneous group unlikely to respond equally to a single preventive intervention such as 17-α hydroxyprogesterone caproate. Further confounding this issue is our fundamental lack of knowledge about the mechanism(s) by which 17-α hydroxyprogesterone caproate reduces preterm birth. Recently, studies demonstrating that responders and nonresponders can be identified based on obstetric history, genotype, physical characteristics, and behavioral factors have begun to provide clues into both 17-α hydroxyprogesterone caproate's mechanism and the pathophysiology of recurrent preterm birth and may allow for more targeted therapy. These studies lend support to speculation that inflammation or nitric oxide metabolism may be common threads between 17-α hydroxyprogesterone caproate's mechanism and preterm birth prevention. It will remain critically important to avoid the temptation to regard prior spontaneous preterm birth as a single disease entity amenable to a single treatment.

[Effects of chronic tabacco smoking on the cerebral blood flow]

AIM

To study an effect of chronic smoking on cerebral hemodynamics and cerebrovascular reactivity in different segments of the arterial system of the brain in men.

MATERIAL AND METHODS

Male patients enrolled in the study were divided into two groups: controls (n=11) and smokers (n=24) with index 30.7 pack-year smoking history. Haemorheological parameters: viscosity of blood, aggregation of erythrocytes, hematocrit, fibrinogen were evaluated in both groups. Using carotid duplex ultrasound (MyLab 50 Esaote, Italy), intima-media thickness (IMT) of common carotid arteries (CCA) was measured. Parameters of cerebral hemodynamics were evaluated using transcranial Doppler ultrasound (Nicolet Companion Biomedikal, USA). Tests of the cerebrovascular reactivity were used to study arteries of three levels: common carotid arteries, middle cerebral arteries (MCA) and pial arteries.

RESULTS

An increase in erythrocytes, hemoglobin, hematocrit, viscosity of blood, aggregation of erythrocytes and fibrinogen was found in the group of smokers compared to the control group. There were an increase in IMT of CCA by more than 50% and a decrease in the mean flow velocity in CCA in smokers. Also smoking decreased MCA mean flow velocity, but this decrease was 2-3 times smaller than in the common carotid arteries. Vasoconstrictor reactions prevailed in MCA, as indicated by the increase in the peripheral vascular resistance index. An increase in vasospastic reactions in pial arteries in smokers was discovered. At the same time, the vasodilatation reaction was maintained or not significantly reduced in pial arteries.

CONCLUSION

Chronic smoking is one of the significant factors causing changes in haemorheological parameters, damage of vascular wall, initiation of atherogenesis and disturbance of cerebral hemodynamics. The study of velocity characteristics and peripheral vascular resistance indices in the group of smokers revealed different reactions of different segments of the brain arterial system.

Effect of tobacco smoke on hydrogen sulfide-induced rat thoracic aorta relaxation

Levels of hydrogen sulfide (H₂S), a gaseous signaling molecule, are reduced in the serum of individuals who smoke. We hypothesized that tobacco smoke influenced smooth muscle relaxation by decreasing H₂S levels and this effect could also influence expression of cystathionine γ-lyase (CSE) and sulfonylurea receptor-2 (SUR-2). The aim of this study was to explore the effect of tobacco smoke on H₂S-mediated rat thoracic aorta relaxation and its possible mechanism. Thirty-two Sprague-Dawley rats were divided into four groups: control (C) group, short-term smoker (SS) group, mid-term smoker (MS) group, and long-term smoker (LS) group. H₂S concentrations in serum, action of H₂S on rat aortic vascular relaxation, and expression of CSE and SUR-2 in thoracic aortic smooth muscle were measured. Although there was no significant difference in H₂S between the C and the SS groups, concentration of H₂S was significantly reduced in both the LS and MS groups compared to control (P<0.01). Furthermore, H₂S was significantly lower in the LS than in the MS group (P<0.05). Rat aortic vascular relaxation was lower in all three treatment groups compared to the control, with the most significant decrease observed in the LS group (P<0.05 compared to the MS group). Expression of CSE and SUR-2 was reduced in the LS and MS groups compared to control (P<0.05), with the lowest levels observed in the LS group (P<0.05). Therefore, tobacco smoke reduced expression of CSE and SUR-2 in rat thoracic aorta, which may inhibit H₂S production and vascular dilation.

Exposure to cigarette smoke abrogates the beneficial effect of ischemic postconditioning

Cigarette smoking is one of the risk factors for coronary artery disease. Although conditioning decreases infarct size in hearts from healthy animals, comorbidities may render it ineffective. We investigated the effects of cigarette smoke (CS) exposure on intracellular myocardial signaling, infarct size after ischemia-reperfusion, and the potential interference with ischemic conditioning. Exposure of mice to CS increased blood pressure, caused cardiac hypertrophy, and upregulated the nitric oxide synthatse (NOS)/soluble guanylate cyclase (sGC)/cGMP pathway. To test the effect of CS exposure on the endogenous cardioprotective mechanisms, mice were subjected to regional myocardial ischemia and reperfusion with no further intervention or application of preconditioning (PreC) or postconditioning (PostC). Exposure to CS did not increase the infarction compared with the room air (RA)-exposed group. PreC was beneficial for both CS and RA vs. nonconditioned animals. PostC was effective only in RA animals, while the infarct size-limiting effect was not preserved in the CS group. Differences in oxidative stress markers, Akt, and endothelial NOS phosphorylation and cGMP levels were observed between RA and CS groups subjected to PostC. In conclusion, exposure to CS does not per se increase infarct size. The beneficial effect of ischemic PreC is preserved in mice exposed to CS, as it does not affect the cardioprotective signaling; in contrast, PostC fails to protect CS-exposed mice due to impaired activation of the Akt/eNOS/cGMP axis that occurs in parallel to enhanced oxidative stress.

Cardiovascular Consequences of Childhood Secondhand Tobacco Smoke Exposure: Prevailing Evidence, Burden, and Racial and Socioeconomic Disparities: A Scientific Statement From the American Heart Association

BACKGROUND

Although public health programs have led to a substantial decrease in the prevalence of tobacco smoking, the adverse health effects of tobacco smoke exposure are by no means a thing of the past. In the United States, 4 of 10 school-aged children and 1 of 3 adolescents are involuntarily exposed to secondhand tobacco smoke (SHS), with children of minority ethnic backgrounds and those living in low-socioeconomic-status households being disproportionately affected (68% and 43%, respectively). Children are particularly vulnerable, with little control over home and social environment, and lack the understanding, agency, and ability to avoid SHS exposure on their own volition; they also have physiological or behavioral characteristics that render them especially susceptible to effects of SHS. Side-stream smoke (the smoke emanating from the burning end of the cigarette), a major component of SHS, contains a higher concentration of some toxins than mainstream smoke (inhaled by the smoker directly), making SHS potentially as dangerous as or even more dangerous than direct smoking. Compelling animal and human evidence shows that SHS exposure during childhood is detrimental to arterial function and structure, resulting in premature atherosclerosis and its cardiovascular consequences. Childhood SHS exposure is also related to impaired cardiac autonomic function and changes in heart rate variability. In addition, childhood SHS exposure is associated with clustering of cardiometabolic risk factors such as obesity, dyslipidemia, and insulin resistance. Individualized interventions to reduce childhood exposure to SHS are shown to be at least modestly effective, as are broader-based policy initiatives such as community smoking bans and increased taxation.

PURPOSE

The purpose of this statement is to summarize the available evidence on the cardiovascular health consequences of childhood SHS exposure; this will support ongoing efforts to further reduce and eliminate SHS exposure in this vulnerable population. This statement reviews relevant data from epidemiological studies, laboratory-based experiments, and controlled behavioral trials concerning SHS and cardiovascular disease risk in children. Information on the effects of SHS exposure on the cardiovascular system in animal and pediatric studies, including vascular disruption and platelet activation, oxidation and inflammation, endothelial dysfunction, increased vascular stiffness, changes in vascular structure, and autonomic dysfunction, is examined.

CONCLUSIONS

The epidemiological, observational, and experimental evidence accumulated to date demonstrates the detrimental cardiovascular consequences of SHS exposure in children.

IMPLICATIONS

Increased awareness of the adverse, lifetime cardiovascular consequences of childhood SHS may facilitate the development of innovative individual, family-centered, and community health interventions to reduce and ideally eliminate SHS exposure in the vulnerable pediatric population. This evidence calls for a robust public health policy that embraces zero tolerance of childhood SHS exposure.

Improvement in blood pressure after short-term inorganic nitrate supplementation is attenuated in cigarette smokers compared to non-smoking controls

Dietary supplementation with inorganic nitrate (NO₃^-) has been reported to improve cardiovascular health indices in healthy adults. Cigarette smoking increases circulating thiocyanate (SCN^-), which has been suggested to competitively inhibit salivary nitrate (NO₃^-) uptake, a rate-limiting step in dietary NO₃^- metabolism. Therefore, this study tested the hypothesis that dietary NO₃^- supplementation would be less effective at increasing the circulating plasma nitrite concentration ([NO₂^-]) and lowering blood pressure in smokers (S) compared to non-smokers (NS). Nine healthy smokers and eight healthy non-smoking controls reported to the laboratory at baseline (CON) and following six day supplementation periods with 140 mL day^-1 NO₃^--rich (8.4 mmol NO₃^- day^-1; NIT) and NO₃^--depleted (0.08 mmol NO₃^- day^-1; PLA) beetroot juice in a cross-over experiment. Plasma and salivary [SCN^-] were elevated in smokers compared to non-smokers in all experimental conditions (P < 0.05). Plasma and salivary [NO₃^-] and [NO₂^-] were elevated in the NIT condition compared to CON and PLA conditions in smokers and non-smokers (P < 0.05). However, the change in salivary [NO₃^-] (S: 3.5 ± 2.1 vs. NS: 7.5 ± 4.4 mM), plasma [NO₃^-] (S: 484 ± 198 vs. NS: 802 ± 199 μM) and plasma [NO₂^-] (S: 218 ± 128 vs. NS: 559 ± 419 nM) between the CON and NIT conditions was lower in the smokers compared to the non-smokers (P < 0.05). Salivary [NO₂^-] increased above CON to a similar extent with NIT in smokers and non-smokers (P > 0.05). Systolic blood pressure was lowered compared to PLA with NIT in non-smokers (P < 0.05), but not smokers (P > 0.05). These findings suggest that dietary NO₃^- metabolism is compromised in smokers leading to an attenuated blood pressure reduction compared to non-smokers after NO₃^- supplementation. These observations may provide novel insights into the cardiovascular risks associated with cigarette smoking and suggest that this population may be less likely to benefit from improved cardiovascular health if they increase dietary NO₃^- intake.

Effect of passive heat stress on arterial stiffness in smokers versus non-smokers

In non-smokers, passive heat stress increases shear stress and vasodilation, decreasing arterial stiffness. Smokers, who reportedly have arterial dysfunction, may have similar improvements in arterial stiffness with passive heat stress. Therefore, we examined the effects of an acute bout of whole-body passive heat stress on arterial stiffness in smokers vs. non-smokers. Thirteen smokers (8.8 ± 5.5 [median = 6] cigarettes per day for > 4 years) and 13 non-smokers matched for age, mass, height, and exercise habits (27 ± 8 years; 78.8 ± 15.4 kg; 177.6 ± 6.7 cm) were passively heated to 1.5 °C core temperature (T C) increase. At baseline and each 0.5 °C T C increase, peripheral (pPWV) and central pulse wave velocity (cPWV) were measured via Doppler ultrasound. No differences existed between smokers and non-smokers for any variables (all p >  .05), except cPWV slightly increased from baseline (526.7 ± 81.7 cm · s(-1)) to 1.5 °C ΔT C (579.7 ± 69.8 cm · s(-1); p < 0.005), suggesting heat stress acutely increased central arterial stiffness. pPWV did not change with heating (grand mean: baseline = 691.9 ± 92.9 cm · s(-1); 1.5 °C ΔT C = 691.9 ± 79.5 cm · s(-1); p > 0.05). Changes in cPWV and pPWV during heating correlated (p < 0.05) with baseline PWV in smokers (cPWV: r = -0.59; pPWV: r = -0.62) and non-smokers (cPWV: r = -0.45; pPWV: r = -0.77). Independent of smoking status, baseline stiffness appears to mediate the magnitude of heating-induced changes in arterial stiffness.

Exercise intervention as a protective modulator against metabolic disorders in cigarette smokers

[Purpose] assess the impact of exercise intensity on desire to smoke, serum cotinine, stress hormones, total antioxidant capacity, and oxidative free radicals as potential markers of cardiopulmonary metabolic disorders were measured.in cigarette smokers. [Subjects and Methods] The participants (150 randomly selected healthy men, aged 18–55 years) were classified into 4 smoking groups: control (non-smokers; N= 30); mild (N = 33); moderate (N = 42), and heavy (N = 45). The participants were assigned to either moderate (8 weeks) or short-term (20–45 min) exercise training. The desire to smoke, Mood and Physical Symptoms Scale, and Subjective Exercise Experiences Scale scores, cotinine, stress hormones (cortisol and testosterone), free radicals (malondialdehyde, nitric oxide), and total antioxidant capacity were evaluated. [Results] Significant increases in serum cotinine, cortisol, testosterone, nitric oxide, and malondialdehyde levels and a reduction in total antioxidant capacity activity were observed in all smoker groups; heavy smokers showed a higher change in metabolites. In all smoker groups, both short and moderate- intensity exercises significantly reduce cotinine, cortisol, testosterone, and malondialdehyde and increased nitric oxide levels and total antioxidant capacity activity; further, the desire to smoke, Mood and Physical Symptoms Scale, and Subjective Exercise Experiences Scale scores were reduced. This supports the ability of exercise to increase nitric oxide bioavailability, enhance of blood vessels function and ultimately decrease the incidence of cardiopulmonary disorders. [Conclusion] Exercise interventions with varying intensities may be used as nicotine replacement therapy or protective aids against smoking-related cardiopulmonary disorders.

Acute stimulation of mesenchymal stem cells with cigarette smoke extract affects their migration, differentiation, and paracrine potential

Mesenchymal stem cells (MSCs) are known to play a key role in tissue regeneration, while smoking cigarettes is described to impair it. This work focuses on the effect cigarette smoke extract (CSE) has on the migration, differentiation, and paracrine potential of human adipose derived MSCs (AdMSCs). To mimic native conditions in vitro, AdMSCs were cultured in either monolayer or three-dimensional pellet cultures. While constant exposure to high concentrations of CSE had lethal effects on AdMSCs, lower concentrations of CSE impaired cell migration when compared to control conditions. The secretion of key interleukins was downregulated when CSE was exposed to the cells at low concentrations. Moreover, in this work AdMSCs were exposed to CSE while simultaneously being induced to differentiate into adipocytes, osteoblasts, and chondrocytes to determine the effect of CSE on the cells potential to differentiate. While adipogenic differentiation showed no significant variation, AdMSCs exposed to osteogenic and chondrogenic supplements showed both early and late genetic level variation when acutely exposed to low concentrations of CSE. Our results indicate that even a small amount of cigarette smoke can have detrimental effects on the regenerative potential of MSCs.

Effect of Diet and Age on Arterial Stiffening Due to Atherosclerosis in ApoE(-/-) Mice

This work analyzes the progressive stiffening of the aorta due to atherosclerosis development of both ApoE(-/-) and C57BL/6J mice fed on a Western (n = 5) and a normal (n = 5) chow diet for the ApoE(-/-) group and on a normal chow diet (n = 5) for the C57BL/6J group. Sets of 5 animals from the three groups were killed after 10, 20, 30 and 40 weeks on their respective diets (corresponding to 17, 27, 37 and 47 weeks of age). Mechanical properties (inflation test and axial residual stress measurements) and histological properties were compared for both strains, ApoE(-/-) on the hyper-lipidic diet and both ApoE(-/-) and C57BL/6J on the normal diet, after the same period and after different periods of diet. The results indicated that the aorta stiffness in the ApoE(-/-) and C57BL/6J mice under normal diet remained approximately constant irrespective of their age. However, the arterial stiffness in the ApoE(-/-) on the hyper-lipidic diet increased over time. Statistical differences were found between the group after 10 weeks and the groups after 30 and 40 weeks of a hyper-lipidic diet. Comparing the hyper-lipidic and normal diet mice, statistical differences were also found between both diets in all cases after 40 weeks of diet, frequently after 30 weeks, and in some cases after 20 weeks. The early stages of lesion corresponded to the first 2 weeks of diet. Advanced lesions were found at 30 weeks and, finally, the aorta was completely damaged after 40 weeks of diet. In conclusion, we found substantial changes in the mechanical properties of the aorta walls of the ApoE(-/-) mice fed with the hyper-lipidic diet compared to the normal chow diet groups for both the ApoE(-/-) and C57BL/6J groups. These findings could serve as a reference for the study of changes in the arterial wall properties in cases of atherosclerosis.

Effects of cigarette smoking on erectile dysfunction

Cigarette smoking is a leading cause of preventable morbidity and mortality in the United States. Although public policies have resulted in a decreased number of new smokers, smoking rates remain stubbornly high in certain demographics with 20% of all American middle-aged men smoking. In addition to the well-established harmful effects of smoking (i.e. coronary artery disease and lung cancer), the past three decades have led to a compendium of evidence being compiled into the development of a relationship between cigarette smoking and erectile dysfunction. The main physiologic mechanism that appears to be affected includes the nitric oxide signal transduction pathway. This review details the recent literature linking cigarette smoking to erectile dysfunction, epidemiological associations, dose dependency and the effects of smoking cessation on improving erectile quality.

Aortic remodelling in chronic nicotine-administered rat

Vascular remodelling is an adaptive mechanism, which counteracts pressure changes in blood circulation. Nicotine content in cigarette increases the risk of hypertension. The exact relationship between nicotine and vascular remodelling still remain unknown. Current study was aimed to determine the effect of clinically relevant dosage of nicotine (equivalent to light smoker) on aortic reactivity, oxidative stress markers and histomorphological changes. Twelve age-matched male Sprague-Dawley rats were randomly divided into two groups, i.e.: normal saline as control or 0.6 mg/kg nicotine for 28 days (i.p., n=6 per group). On day-29, the rats were sacrificed and the thoracic aorta was dissected immediately for further studies. Mean arterial pressure (MAP) and pulse pressure (PP) of nicotine-treated vs. control were significantly increased (p<0.05). Nicotine-treated group showed significant (p<0.05) increase tunica media thickness, and decrease in lumen diameter, suggesting vascular remodelling which lead to prior hypertension state. The phenylephrine (PE)-induced contractile response in nicotine group was significantly higher than control group (ED50=1.44×10(5) M vs. 4.9×10(6) M) (p<0.05~0.001). However, nicotine-treated rat showed significantly lower endothelium-dependent relaxation response to acetylcholine (ACh) than in control group (ED50=6.17×10(7) M vs. 2.82×10(7) M) (p<0.05), indicating loss of primary vascular function. Malondialdehyde (MDA), a lipid peroxidation marker was significantly higher in nicotine group. Superoxide dismutase (SOD) enzymatic activity and glutathione (GSH) were all reduced in nicotine group (p<0.05) vs. control, suggesting nicotine induces oxidative imbalance. In short, chronic nicotine administration impaired aortic reactivity, probably via redox imbalance and vascular remodelling mechanism.

Smoking and Cardiovascular Disease

Smoking represents one of the most important preventable risk factors for the development of atherosclerosis. The present review aims at providing a comprehensive summary of published data from clinical and animal studies, as well as results of basic research on the proatherogenic effect of smoking. Extensive search and review of literature revealed a vast amount of data on the influence of cigarette smoke and its constituents on early atherogenesis, particularly on endothelial cells. Vascular dysfunction induced by smoking is initiated by reduced nitric oxide (NO) bioavailability and further by the increased expression of adhesion molecules and subsequent endothelial dysfunction. Smoking-induced increased adherence of platelets and macrophages provokes the development of a procoagulant and inflammatory environment. After transendothelial migration and activation, macrophages take up oxidized lipoproteins arising from oxidative modifications and transdifferentiate into foam cells. In addition to direct physical damage to endothelial cells, smoking induces tissue remodeling, and prothrombotic processes together with activation of systemic inflammatory signals, all of which contribute to atherogenic vessel wall changes. There are still great gaps in our knowledge about the effects of smoking on cardiovascular disease. However, we know that smoking cessation is the most effective measure for reversing damage that has already occurred and preventing fatal cardiovascular outcomes.

Could spatial heterogeneity in human vocal fold elastic properties improve the quality of phonation?

The physical mechanisms leading to the acoustic and perceptual qualities of voice are not well understood. This study examines the spatial distribution of biomechanical properties in human vocal folds and explores the consequences of these properties on phonation. Vocal fold lamina propria specimens isolated from nine excised human male larynges were tested in uniaxial tension (six from non-smokers, three from smokers). An optical method was employed to determine the local stretch, from which the elastic modulus of three segments in the anterior-posterior direction was calculated. Several specimens exhibited a significant heterogeneity in the modulus with the middle segment stiffer than the other segments. It was concluded that such modulus gradients are stronger in specimens from non-smokers than smokers. To understand the functional implications of a modulus gradient, the first eigenmode of vibration was calculated with a finite element model. With a modulus gradient, the vocal fold's eigenmode deflection was spread along the anterior-posterior length, whereas for a homogeneous modulus distribution, the deflection was more focused around the mid-coronal plane. Consequently, the strong modulus gradient may enable more complete glottal closure, which is important for normal phonation, while a more homogeneous modulus may be responsible for poor glottal closure and a perceived "breathy" voice.

Impact of smoking and smoking cessation on arterial stiffness in healthy participants

Smoking is associated with increased arterial stiffness. However, the impact of smoking cessation on arterial stiffness remains unknown. We investigated the effect of smoking cessation on arterial stiffness. Healthy participants (n = 209) were divided into nonsmoking (NSm, n = 96), quit smoking (QSm, n = 61), and maintained smoking groups (MSm, n = 52). Arterial stiffness indexes (ankle-brachial index [ABI] and brachial-ankle pulse wave velocity [baPWV]) were assessed at baseline, and after 6 and 12 months. Baseline, arterial stiffness was significantly higher in the MSm and QSm groups than in the NSm group (P < .001). In the QSm group, there was significant difference in ABI between baseline and 12 months (P = .03). No significant differences were shown in baPWV. Both ABI and baPWV were similar between QSm and MSm group at 12 months. However, there was significant difference between QSm and NSm groups (P < .001). This study shows that 12 months of smoking cessation is associated with improved arterial stiffness.

Chronic cigarette smoking causes hypertension, increased oxidative stress, impaired NO bioavailability, endothelial dysfunction, and cardiac remodeling in mice

Cigarette smoking is a major independent risk factor for cardiovascular disease. While the association between chronic smoking and cardiovascular disease is well established, the underlying mechanisms are incompletely understood, partly due to the lack of adequate in vivo animal models. Here, we report a mouse model of chronic smoking-induced cardiovascular pathology. Male C57BL/6J mice were exposed to whole body mainstream cigarette smoke (CS) using a SCIREQ "InExpose" smoking system (48 min/day, 5 days/wk) for 16 or 32 wk. Age-matched, air-exposed mice served as nonsmoking controls. Blood pressure was measured, and cardiac MRI was performed. In vitro vascular ring and isolated heart experiments were performed to measure vascular reactivity and cardiac function. Blood from control and smoking mice was studied for the nitric oxide (NO) decay rate and reactive oxygen species (ROS) generation. With 32 wk of CS exposure, mice had significantly less body weight gain and markedly higher blood pressure. At 32 wk of CS exposure, ACh-induced vasorelaxation was significantly shifted to the right and downward, left ventricular mass was significantly larger along with an increased heart-to-body weight ratio, in vitro cardiac function tended to be impaired with high afterload, white blood cells had significantly higher ROS generation, and the blood NO decay rate was significantly faster. Thus, smoking led to blunted weight gain, hypertension, endothelial dysfunction, leukocyte activation with ROS generation, decreased NO bioavailability, and mild cardiac hypertrophy in mice that were not otherwise predisposed to disease. This mouse model is a useful tool to enable further elucidation of the molecular and cellular mechanisms of smoking-induced cardiovascular diseases.

Chlorine gas exposure causes systemic endothelial dysfunction by inhibiting endothelial nitric oxide synthase-dependent signaling

Chlorine gas (Cl(2)) exposure during accidents or in the military setting results primarily in injury to the lungs. However, the potential for Cl(2) exposure to promote injury to the systemic vasculature leading to compromised vascular function has not been studied. We hypothesized that Cl(2) promotes extrapulmonary endothelial dysfunction characterized by a loss of endothelial nitric oxide synthase (eNOS)-derived signaling. Male Sprague Dawley rats were exposed to Cl(2) for 30 minutes, and eNOS-dependent vasodilation of aorta as a function of Cl(2) dose (0-400 ppm) and time after exposure (0-48 h) were determined. Exposure to Cl(2) (250-400 ppm) significantly inhibited eNOS-dependent vasodilation (stimulated by acetycholine) at 24 to 48 hours after exposure without affecting constriction responses to phenylephrine or vasodilation responses to an NO donor, suggesting decreased NO formation. Consistent with this hypothesis, eNOS protein expression was significantly decreased (∼ 60%) in aorta isolated from Cl(2)-exposed versus air-exposed rats. Moreover, inducible nitric oxide synthase (iNOS) mRNA was up-regulated in circulating leukocytes and aorta isolated 24 hours after Cl(2) exposure, suggesting stimulation of inflammation in the systemic vasculature. Despite decreased eNOS expression and activity, no changes in mean arterial blood pressure were observed. However, injection of 1400W, a selective inhibitor of iNOS, increased mean arterial blood pressure only in Cl(2)-exposed animals, suggesting that iNOS-derived NO compensates for decreased eNOS-derived NO. These results highlight the potential for Cl(2) exposure to promote postexposure systemic endothelial dysfunction via disruption of vascular NO homeostasis mechanisms.

Alteration of the material properties of the normal supraspinatus tendon by nicotine treatment in a rat model

BACKGROUND AND PURPOSE

Several studies have shown that nicotine has a detrimental effect on the development of rotator cuff tear. However, little is known about its mechanism. We evaluated the effect of nicotine on the maximum tensile load, the maximum tensile stress, and the elastic modulus of the supraspinatus tendon in a rat model.

METHODS

27 rats were randomly assigned to 3 groups. Subcutaneously implanted osmotic pumps delivered two different concentrations of nicotine solution (high dose: 45 ng/mL; low dose: 22.5 ng/mL) or saline solution (controls) over a 12-week period. The level of serum cotinine, a breakdown product of nicotine, was evaluated. We performed tensile testing using the left supraspinatus tendon in each rat. The maximum load of the supraspinatus tendon was measured, and the maximum tensile stress and elastic modulus were calculated.

RESULTS

Serum cotinine levels showed controlled systemic release of nicotine. The maximum tensile load and stress were similar in the three groups. The elastic modulus was, however, higher in the nicotine groups than in the control group.

INTERPRETATION

In a rat model, nicotine caused a change in the material properties of the supraspinatus tendon. This change may predispose to a tear in the supraspinatus tendon.

Using blood pressure telemetry to assess acute changes in arterial stiffness in rats after nitric oxide synthase inhibition or environmental tobacco smoke exposure

Although environmental tobacco smoke (ETS) exposure has been reported to acutely increase arterial stiffness in humans, understanding of the underlying mechanisms is unclear and few studies have measured these effects in experimental animals. One potential mechanism for the increased arterial stiffness is reduced nitric oxide (NO) bioactivity as a result of oxidative stress. Thus, the objective of this study was to determine whether acute changes in arterial stiffness could be detected using arterial pulse wave dP/dt in blood pressure telemetry implanted rats and to investigate the role of NO in regulating dP/dt. Intravenous injection of acetylcholine (0.91 ng/kg) decreased and norepinephrine (0.02 mg/kg) increased dP/dt compared to saline vehicle (0.5 mL/kg). Injection of the NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME; 30 mg/kg) decreased plasma nitrate/nitrite (NOx), but transiently increased dP/dt. ETS at low and high doses had no effect on dP/dt, but increased plasma NOx levels at high ETS exposure and increased plasma nitrotyrosine levels in both ETS groups. In conclusion, acute changes in NO production via acetylcholine or L-NAME alter the arterial pulse wave dP/dt consistently with the predicted changes in arterial stiffness. Although acute ETS appears to biologically inactivate NO, a concomitant increase in NO production at high ETS exposure may explain why dP/dt was not acutely altered by ETS in the current study.

Continuous smoking and progression of arterial stiffening: a prospective study

OBJECTIVES

We prospectively and longitudinally determined the effects of smoking on the progression of arterial stiffening as well as the involvement of inflammation in this process.

BACKGROUND

Smoking is an important avoidable risk factor for cardiovascular disease, and arterial stiffness might be involved in the pathophysiology. No prospective study has examined the effect of continuous smoking on the age-associated progression of arterial stiffening.

METHODS

In 2,054 Japanese subjects (40 +/- 8 years of age), brachial-ankle pulse wave velocity (baPWV) and serum C-reactive protein (CRP) levels were measured at the baseline and the end of a 5- to 6-year follow-up period.

RESULTS

The annual rate of change of the baPWV during the study period was significantly greater in the continuous heavy smokers (11.0 +/- 1.9 cm/s/year, n = 181) than in the never-smokers (5.5 +/- 0.6 cm/s/year, n = 1,018). This difference remained significant even after adjustments for covariates, including age (p < 0.05). In continuous smokers (n = 493), the mean number of cigarettes smoked/day during the study period showed a significant relationship with the changes in baPWV. No significant relationship was found between the change in baPWV and serum CRP levels.

CONCLUSIONS

Continuous smoking might accelerate the age-associated progression of structural stiffening of the large- to middle-size arteries. We also found a dose-response relationship between cigarette consumption and accelerated arterial stiffening. However, we failed to confirm any significant association between the rate of arterial stiffening and the serum CRP levels in the smokers.

Glutathione-S-transferase P protects against endothelial dysfunction induced by exposure to tobacco smoke

Exposure to tobacco smoke impairs endothelium-dependent arterial dilation. Reactive constituents of cigarette smoke are metabolized and detoxified by glutathione-S-transferases (GSTs). Although polymorphisms in GST genes are associated with the risk of cancer in smokers, the role of these enzymes in regulating the cardiovascular effects of smoking has not been studied. The P isoform of GST (GSTP), which catalyzes the conjugation of electrophilic molecules in cigarette smoke such as acrolein, was expressed in high abundance in the mouse lung and aorta. Exposure to tobacco smoke for 3 days (5 h/day) decreased total plasma protein. These changes were exaggerated in GSTP(-/-) mice. Aortic rings isolated from tobacco smoke-exposed GSTP(-/-) mice showed greater attenuation of ACh-evoked relaxation than those from GSTP(+/+) mice. The lung, plasma, and aorta of mice exposed to tobacco smoke or acrolein (for 5 h) accumulated more acrolein-adducted proteins than those tissues of mice exposed to air, indicating that exposure to tobacco smoke results in the systemic delivery of acrolein. Relative to GSTP(+/+) mice, modification of some proteins by acrolein was increased in the aorta of GSTP(-/-) mice. Aortic rings prepared from GSTP(-/-) mice that inhaled acrolein (1 ppm, 5 h/day for 3 days) or those exposed to acrolein in an organ bath showed diminished ACh-induced arterial relaxation more strongly than GSTP(+/+) mice. Acrolein-induced endothelial dysfunction was prevented by pretreatment of the aorta with N-acetylcysteine. These results indicate that GSTP protects against the endothelial dysfunction induced by tobacco smoke exposure and that this protection may be related to the detoxification of acrolein or other related cigarette smoke constituents.

Decreased aortic elasticity in healthy 11-year-old children exposed to tobacco smoke

OBJECTIVE

The goal was to assess the relationship between passive smoking and arterial elasticity in children.

METHODS

Healthy 11-year-old children (N = 386) from an atherosclerosis prevention trial (Special Turku Coronary Risk Factor Intervention Project for Children) were studied. Aortic and carotid elasticities were determined by using M-mode ultrasound imaging based on measurements of blood pressure and arterial diameter changes during the cardiac cycle. The aortic stiffness index, Young's elastic modulus, and distensibility and the respective indices for the carotid artery were calculated. Exposure to tobacco smoke was measured by using serum cotinine concentrations, and children were classified into 3 groups, that is, the noncotinine group (n = 220; undetectable cotinine levels), the low-cotinine group (n = 127; cotinine levels of 0.2-1.6 ng/mL), and the top-decile cotinine group (n = 39; cotinine levels of > or =1.7 ng/mL).

RESULTS

Higher cotinine concentrations were associated with increased aortic stiffness index values. An increase in aortic Young's elastic modulus and a decrease in aortic distensibility were observed across the cotinine groups. In multivariate regression models, the cotinine level remained a significant explanatory variable regarding all aortic elasticity indices. Carotid elasticity indices showed no differences across the cotinine groups.

CONCLUSIONS

Childhood exposure to tobacco smoke (verified with serum cotinine levels) decreases aortic elastic properties in healthy children.

Relation of nitrite to structural and mechanical adaptation of arteries during postnatal development

Mammalian arteries undergo rapid remodeling during postnatal growth and development. The high wall shear stress at birth is an important mediator of postnatal endothelial nitric oxide (NO) and consequently of growth and remodeling. The objective of this study was to quantify the NO production in relation to geometric and mechanical remodeling of aorta and pulmonary artery during postnatal development. Fifty-one C57BL/6 mice aged from 1 to 33 days were divided into 8 age groups for measurements of nitrite (NO(x)). Systematic measurements of NO(x) in each rings were made in the main pulmonary artery and primary branch as well as along the length of aorta using the combination of a diazo coupling method and high-performance liquid chromatography. The NO(x) data on the aorta were correlated with data on the geometry (diameter, wall thickness) and mechanical properties (stress, strain, elastic modulus) in the same strain of mice under the same conditions. Our findings show postnatal age and vessel size affects the NO production; i.e., the NO(x) decreased with age and diameter. Furthermore, there is a significant positive correlation between strain and NO(x) but negative correlation between both wall thickness and elastic modulus and NO(x) levels. These findings suggest an important interplay between NO(x) and geometric and mechanical remodeling during postnatal growth and development.

Effects of cilostazol and pentoxifylline on forearm reactive hyperemia response, lipid profile, oxidative stress, and inflammatory markers in patients with intermittent claudication

Peripheral arterial disease may lead to lower limb claudication and increased risk of systemic vascular dysfunction. In this article, the authors have investigated the peripheral vascular dysfunction evaluating forearm blood flow using venous occlusion plethysmography, lipid profile, and C-reactive protein in 60 patients with moderate intermittent claudication treated during 20 weeks with placebo (n = 16), cilostazol (200 mg/d; n = 17), or pentoxifylline (1200 mg/d; n = 15) in a randomized double-blinded clinical trial, taking into account smoking. Forearm blood flow after reactive hyperemia response (FBF(h) ) or oral nitroglycerine spray to evaluate endothelial-dependent and endothelial-independent vasodilation, respectively, pain-free and maximal walking distance, levels of C-reactive protein, triglycerides, cholesterol, low-density lipoprotein, and high-density lipoprotein-cholesterol in plasma were determined. The results showed that there was an improvement in the high-density lipoprotein-cholesterol, pain-free and maximal walking distance, and FBF(h) independent of treatment in nonsmoking patients. Cilostazol increased high-density lipoprotein-cholesterol level, maximal walking distance, and FBF(h), whereas pentoxifylline reduced C-reactive protein level and increased maximal walking distance in total and nonsmoking groups. No treatment was effective in smokers.

Cigarette smoking and erectile dysfunction: focus on NO bioavailability and ROS generation

INTRODUCTION

Thirty million men in the United States suffer from erectile dysfunction (ED) and this number is expected to double by 2025. Considered a major public health problem, which seriously affects the quality of life of patients and their partners, ED becomes increasingly prevalent with age and chronic smoking is a major risk factor in the development of ED.

AIM

To review available evidence concerning the effects of cigarette smoking on vascular changes associated with decreased nitric oxide (NO) bioavailability and increased reactive oxygen species (ROS) generation.

METHODS

We examined epidemiological and clinical data linking cigarette smoking and ED, and the effects of smoking on vascular NO bioavailability and ROS generation.

MAIN OUTCOME MEASURES

There are strong parallels between smoking and ED and considerable evidence supporting the concept that smoking-related ED is associated with reduced bioavailability of NO because of increased ROS.

RESULTS

Cigarette smoking-induced ED in human and animal models is associated with impaired arterial flow to the penis or acute vasospasm of the penile arteries. Long-term smoking produces detrimental effects on the vascular endothelium and peripheral nerves and also causes ultrastructural damage to the corporal tissue, all considered to play a role in chronic smoking-induced ED. Clinical and basic science studies provide strong indirect evidence that smoking may affect penile erection by the impairment of endothelium-dependent smooth muscle relaxation or more specifically by affecting NO production via increased ROS generation. Whether nicotine or other products of cigarette smoke mediate all effects related to vascular damage is still unknown.

CONCLUSIONS

Smoking prevention represents an important approach for reducing the risk of ED. The characterization of the components of cigarette smoke leading to ED and the mechanisms by which these components alter signaling pathways activated in erectile responses are necessary for a complete comprehension of cigarette smoking-associated ED.