Background Marijuana leaf vaporizers, which heat plant material and sublimate Δ‐9‐tetrahydrocannabinol without combustion, are popular alternatives to smoking cannabis that are generally perceived to be less harmful. We have shown that smoke from tobacco and marijuana, as well as aerosol from e‐cigarettes and heated tobacco products, impair vascular endothelial function in rats measured as arterial flow‐mediated dilation (FMD). Methods and Results We exposed 8 rats per group to aerosol generated by 2 vaporizer systems (Volcano and handheld Yocan) using marijuana with varying Δ‐9‐tetrahydrocannabinol levels, in a single pulsatile exposure session of 2 s/min over 5 minutes, and measured changes in FMD. To model secondhand exposure, we exposed rats for 1 minute to diluted aerosol approximating release of uninhaled Volcano aerosol into typical residential rooms. Exposure to aerosol from marijuana with and without cannabinoids impaired FMD by ≈50%. FMD was similarly impaired by aerosols from Yocan (237 °C), and from Volcano at both its standard temperature (185 °C) and the minimum sublimation temperature of Δ‐9‐tetrahydrocannabinol (157 °C), although the low‐temperature aerosol condition did not effectively deliver Δ‐9‐tetrahydrocannabinol to the circulation. Modeled secondhand exposure based on diluted Volcano aerosol also impaired FMD. FMD was not affected in rats exposed to clean air or water vapor passed through the Volcano system. Conclusions Acute direct exposure and modeled secondhand exposure to marijuana leaf vaporizer aerosol, regardless of cannabinoid concentration or aerosol generation temperature, impair endothelial function in rats comparably to marijuana smoke. Our findings indicate that use of leaf vaporizers is unlikely to reduce the vascular risk burden of smoking marijuana.

Aims Acute myocardial infarction (MI) causes inflammation, collagen deposition, and reparative fibrosis in response to myocyte death and, subsequently, a pathological myocardial remodelling process characterized by excessive interstitial fibrosis, driving heart failure (HF). Nonetheless, how or when to limit excessive fibrosis for therapeutic purposes remains uncertain. Galectin-3, a major mediator of organ fibrosis, promotes cardiac fibrosis and remodelling. We performed a preclinical assessment of a protein inhibitor of galectin-3 (its C-terminal domain, Gal-3C) to limit excessive fibrosis resulting from MI and prevent ventricular enlargement and HF. Methods and results Gal-3C was produced by enzymatic cleavage of full-length galectin-3 or by direct expression of the truncated form in Escherichia coli. Gal-3C was intravenously administered for 7 days in acute MI models of young and aged rats, starting either pre-MI or 4 days post-MI. Echocardiography, haemodynamics, histology, and molecular and cellular analyses were performed to assess post-MI cardiac functionality and pathological fibrotic progression. Gal-3C profoundly benefitted left ventricular ejection fraction, end-systolic and end-diastolic volumes, haemodynamic parameters, infarct scar size, and interstitial fibrosis, with better therapeutic efficacy than losartan and spironolactone monotherapies over the 56-day study. Gal-3C therapy in post-MI aged rats substantially improved pump function and attenuated ventricular dilation, preventing progressive HF. Gal-3C in vitro treatment of M2-polarized macrophage-like cells reduced their M2-phenotypic expression of arginase-1 and interleukin-10. Gal-3C inhibited M2 polarization of cardiac macrophages during reparative response post-MI. Gal-3C impeded progressive fibrosis post-MI by down-regulating galectin-3-mediated profibrotic signalling cascades including a reduction in endogenous arginase-1 and inducible nitric oxide synthase (iNOS). Conclusion Gal-3C treatment improved long-term cardiac function post-MI by reduction in the wound-healing response, and inhibition of inflammatory fibrogenic signalling to avert an augmentation of fibrosis in the periinfarct region. Thus, Gal-3C treatment prevented the infarcted heart from extensive fibrosis that accelerates the development of HF, providing a potential targeted therapy.

Background: Increasing cannabis legalization has led to a surge in cannabis use. To understand the consequences for cardiovascular health, we have initiated the CANnabis: Does It Damage Endothelium (CANDIDE) study. Here, we report results of an interim analysis. Aims: To investigate the effects of chronic cannabis product use on endothelial function. Approach: We recruited 44 healthy non-tobacco smokers/vapers, 21-50 yrs, in 3 groups based on chronic cannabis use: cannabis smokers, THC edible users, and nonusers. Participants underwent assessment of brachial artery flow-mediated dilation (FMD) and carotid-femoral pulse wave velocity (PWV). Human umbilical vein endothelial cells (ECs) were exposed to sera from each individual with and without VEGF to determine serum effects on endothelial NO production. Human lung microvascular ECs were also exposed to the individual sera and cell permeability was measured by electric cell-substrate impedance sensing. Results: FMD and VEGF-stimulated NO levels were both significantly lower in cannabis smokers than nonusers (5.7±3.3% vs 12.0±8.0%, p=.037, and 1.1±0.3 nM vs 1.5±0.3 nM, p=.018, respectively; figure), comparable effects to what we have reported for tobacco smokers. In contrast, FMD, but not VEGF-stimulated NO levels, was lower in the THC edible users than nonusers (5.0±4.1% vs 12.0±8.0%, p=.031, and 1.6±0.3 nM vs 1.5±0.3 nM, p=.54). There were no significant differences in other functional properties (p>.48). CD31 and IL-1β, which are circulating inflammatory biomarkers that we showed are elevated in tobacco smokers, were not elevated in cannabis smokers. The inflammatory biomarker PTX3 was lower in cannabis smokers than nonusers (p=.038). Conclusion: Chronic cannabis use impairs endothelial function but may reduce inflammation. Our findings suggest that the impairment caused by smoking cannabis vs edible THC use occurs via distinct mechanisms differing in the involvement of endothelial NO production.

HomeArteriosclerosis, Thrombosis, and Vascular BiologyVol. 43, No. 12Impairment of Endothelial Function by Cigarette Smoke and e-Cigarette Aerosol Requires RAGE No AccessResearch ArticleRequest AccessFull TextAboutView Full TextView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toNo AccessResearch ArticleRequest AccessFull TextImpairment of Endothelial Function by Cigarette Smoke and e-Cigarette Aerosol Requires RAGE Daniel D. Han, Poonam Rao, Huiliang Qiu, Mina Navabzadeh, Xiaoyin Wang, Natasha Goyal, Leila Mohammadi, Abel Huang, Bryanna G. Perez, Suzaynn F. Schick and Matthew L. Springer Daniel D. HanDaniel D. Han https://orcid.org/0000-0001-6742-915X Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. Now with School of Medicine and Dentistry, University of Rochester, NY (D.D.H.). , Poonam RaoPoonam Rao https://orcid.org/0000-0001-6829-6133 Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. Center for Tobacco Control Research and Education (P.R., M.L.S.), University of California, San Francisco. Now with CHRISTUS Good Shepherd/Texas A&M University Internal Medicine Residency Program, Longview (P.R.). , Huiliang QiuHuiliang Qiu https://orcid.org/0000-0001-8625-8974 Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. Now with Department of Cardiovascular Diseases, Physiology and Biomedical Engineering, Mayo Clinic Arizona, Scottsdale (H.Q.). , Mina NavabzadehMina Navabzadeh https://orcid.org/0000-0003-2667-8015 Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. , Xiaoyin WangXiaoyin Wang https://orcid.org/0000-0002-6667-5209 Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. , Natasha GoyalNatasha Goyal https://orcid.org/0009-0007-7929-3270 Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. , Leila MohammadiLeila Mohammadi https://orcid.org/0000-0001-9586-1468 Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. , Abel HuangAbel Huang https://orcid.org/0000-0003-1767-0337 Division of Occupational and Environmental Medicine, Department of Medicine (A.H., B.G.P., S.F.S.), University of California, San Francisco. , Bryanna G. PerezBryanna G. Perez Division of Occupational and Environmental Medicine, Department of Medicine (A.H., B.G.P., S.F.S.), University of California, San Francisco. , Suzaynn F. SchickSuzaynn F. Schick Division of Occupational and Environmental Medicine, Department of Medicine (A.H., B.G.P., S.F.S.), University of California, San Francisco. and Matthew L. SpringerMatthew L. Springer Correspondence to: Matthew L. Springer, PhD, Division of Cardiology, University of California, San Francisco, Box 0124, 513 Parnassus Ave, San Francisco, CA 94143. Email E-mail Address: [email protected] https://orcid.org/0000-0002-6689-8234 Division of Cardiology, Department of Medicine (D.D.H., P.R., H.Q., M.N., X.W., N.G., L.M., M.L.S.), University of California, San Francisco. Cardiovascular Research Institute (M.L.S.), University of California, San Francisco. Center for Tobacco Control Research and Education (P.R., M.L.S.), University of California, San Francisco. Originally published5 Oct 2023https://doi.org/10.1161/ATVBAHA.123.319514Arteriosclerosis, Thrombosis, and Vascular Biology. 2023;43:2369–2371FootnotesFor Sources of Funding and Disclosures, see page 2370.Correspondence to: Matthew L. Springer, PhD, Division of Cardiology, University of California, San Francisco, Box 0124, 513 Parnassus Ave, San Francisco, CA 94143. Email matt.springer@ucsf.eduREFERENCES1. Mohammadi L, Han DD, Xu F, Huang A, Derakhshandeh R, Rao P, Whitlatch A, Cheng J, Keith RJ, Hamburg NM, et al. Chronic E-cigarette use impairs endothelial function on the physiological and cellular levels.Arterioscler Thromb Vasc Biol. 2022; 42:1333–1350. doi: 10.1161/ATVBAHA.121.317749LinkGoogle Scholar2. Nabavizadeh P, Liu J, Rao P, Ibrahim S, Han DD, Derakhshandeh R, Qiu H, Wang X, Glantz SA, Schick SF, et al. Impairment of endothelial function by cigarette smoke is not caused by a specific smoke constituent, but by vagal input from the airway.Arterioscler Thromb Vasc Biol. 2022; 42:1324–1332. doi: 10.1161/ATVBAHA.122.318051LinkGoogle Scholar3. Rao P, Han DD, Tan K, Mohammadi L, Derakhshandeh R, Navabzadeh M, Goyal N, Springer ML. Comparable impairment of vascular endothelial function by a wide range of electronic nicotine delivery devices.Nicotine Tob Res. 2022; 24:1055–1062. doi: 10.1093/ntr/ntac019CrossrefMedlineGoogle Scholar4. Jin L, Lynch J, Richardson A, Lorkiewicz P, Srivastava S, Theis W, Shirk G, Hand A, Bhatnagar A, Srivastava S, et al. Electronic cigarette solvents, pulmonary irritation, and endothelial dysfunction: role of acetaldehyde and formaldehyde.Am J Physiol Heart Circ Physiol. 2021; 320:H1510–H1525. doi: 10.1152/ajpheart.00878.2020CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails December 2023Vol 43, Issue 12 Advertisement Article Information Metrics © 2023 American Heart Association, Inc.https://doi.org/10.1161/ATVBAHA.123.319514PMID: 37795616 Originally publishedOctober 5, 2023 Keywordsanimalsdilatationelectronic nicotine delivery systemsendothelial cellspermeabilityratssmokingPDF download Advertisement Subjects Echocardiography Translational Studies Ultrasound Vascular Biology

Background: The harmful vascular effects of smoking are well established, but the effects of chronic use of electronic cigarettes (e-cigarettes) on endothelial function are less understood. We hypothesized that e-cigarette use causes changes in blood milieu that impair endothelial function. Methods: Endothelial function was measured in chronic e-cigarette users, chronic cigarette smokers, and nonusers. We measured effects of participants’ sera, or e-cigarette aerosol condensate, on NO and H2O2 release and cell permeability in cultured endothelial cells (ECs). Results: E-cigarette users and smokers had lower flow-mediated dilation (FMD) than nonusers. Sera from e-cigarette users and smokers reduced VEGF (vascular endothelial growth factor)-induced NO secretion by ECs relative to nonuser sera, without significant reduction in endothelial NO synthase mRNA or protein levels. E-cigarette user sera caused increased endothelial release of H2O2, and more permeability than nonuser sera. E-cigarette users and smokers exhibited changes in circulating biomarkers of inflammation, thrombosis, and cell adhesion relative to nonusers, but with distinct profiles. E-cigarette user sera had higher concentrations of the receptor for advanced glycation end products (RAGE) ligands S100A8 and HMGB1 (high mobility group box 1) than smoker and nonuser sera, and receptor for advanced glycation end product inhibition reduced permeability induced by e-cigarette user sera but did not affect NO production. Conclusions: Chronic vaping and smoking both impair FMD and cause changes in the blood that inhibit endothelial NO release. Vaping, but not smoking, causes changes in the blood that increase microvascular endothelial permeability and may have a vaping-specific effect on intracellular oxidative state. Our results suggest a role for RAGE in e-cigarette-induced changes in endothelial function.

Introduction: E-cigarette use is known to induce vascular impairment by altering vasomotor and cellular functions of the vascular wall, but the molecular mechanism of e-cigarette-induced vascular impairment is largely unexplored. We investigated whether inhibition of RAGE prevents impairment of vasomotor function from acute e-cigarette exposure Hypothesis: Impairment of endothelial vasodilatory function requires the activation of RAGE. Methods: Anesthetized rats (n=8/group) were exposed to aerosols from flavorless tank style e-cigarettes with and without freebase nicotine (12 mg/ml) or air in a single session of 10 cycles of pulsatile 5s exposure over 5 minutes. For each exposure condition, groups received either 1 mg/kg of RAGE inhibitor FPS-ZM1 or vehicle i.p. 1 hour before exposure (i.e., total of 6 groups). Femoral artery flow-mediated dilation (FMD) was measured using micro-ultrasound before and after exposure. Results: Exposure to e-cigarette aerosol with and without nicotine impaired FMD in vehicle groups (8.3±2.7% pre-exposure vs 4.7±2.4% post-exposure, p=0.01; 9.3±4.6% pre- vs 4.8±2.7% post-, p=0.03, respectively), with no change in air control (9.7±3.2% pre- vs 9.3±3.5% post-, p=0.81). Post-exposure FMD in both aerosol groups with vehicle was lower than that in the air group with vehicle (p=0.01 for each aerosol vs air). However, FPS-ZM1 prevented the FMD impairment by aerosol exposure (with nicotine 9.1±3.5% pre- vs 8.9±2.1% post-, p=0.90; without nicotine 9.5±4.3% pre- vs 7.1±2.0% post-, p=0.17), with no change in air control (7.6±2.7% pre- vs 7.4±3.1% post-, p=0.86). Post-exposure FMD values in both aerosol groups receiving FPS-ZM1 were comparable to the air control (p=0.4 and 0.8, respectively). There were no significant difference in post-exposure FMD in the air groups receiving FPS-ZM1 or vehicle (p>0.99). Conclusions: RAGE mediates e-cigarette-induced acute impairment of endothelial vasodilatory function.

Background The emergence of a plethora of new tobacco products marketed as being less harmful than smoking, such as electronic cigarettes and heated tobacco products, and the increased popularity of recreational marijuana have raised concerns about the potential cardiovascular risk associated with their use. Objective The purpose of this study was to investigate whether the use of novel tobacco products or marijuana can cause the development of proarrhythmic substrate and eventually lead to arrhythmias. Methods Rats were exposed to smoke from tobacco, marijuana, or cannabinoid-depleted marijuana, to aerosol from electronic cigarettes or heated tobacco products, or to clean air once per day for 8 weeks, following by assays for blood pressure, cardiac function, ex vivo electrophysiology, and histochemistry. Results The rats exposed to tobacco or marijuana products exhibited progressively increased systolic blood pressure, decreased cardiac systolic function with chamber dilation, and reduced overall heart rate variability, relative to the clean air negative control group. Atrial fibrillation and ventricular tachycardia testing by ex vivo optical mapping revealed a significantly higher susceptibility to each, with a shortened effective refractory period and prolonged calcium transient duration. Histological analysis indicated that in all exposure conditions except for air, exposure to smoke or aerosol from tobacco or marijuana products caused severe fibrosis with decreased microvessel density and higher level of sympathetic nerve innervation. Conclusion These pathophysiological results indicate that tobacco and marijuana products can induce arrhythmogenic substrates involved in cardiac electrical, structural, and neural remodeling, facilitating the development of arrhythmias.

INTRODUCTION:Electronic nicotine delivery systems (ENDS; ie, vaping devices) such as e-cigarettes, heated tobacco products, and newer coil-less ultrasonic vaping devices are promoted as less harmful alternatives to combustible cigarettes. However, their cardiovascular effects are understudied. We investigated whether exposure to aerosol from a wide range of ENDS devices, including a new ultrasonic vaping device, impairs endothelial function. AIMS AND METHODS:We measured arterial flow-mediated dilation (FMD) in rats (n = 8/group) exposed to single session of 10 cycles of pulsatile 5-second exposure over 5 minutes to aerosol from e-liquids with and without nicotine generated from a USONICIG ultrasonic vaping device, previous generation e-cigarettes, 5% nicotine JUUL pods (Virginia Tobacco, Mango, Menthol), and an IQOS heated tobacco product; with Marlboro Red cigarette smoke and clean air as controls. We evaluated nicotine absorption and serum nitric oxide levels after exposure, and effects of different nicotine acidifiers on platelet aggregation. RESULTS:Aerosol/smoke from all conditions except air significantly impaired FMD. Serum nicotine varied widely from highest in the IQOS group to lowest in USONICIG and previous generation e-cig groups. Nitric oxide levels were not affected by exposure. Exposure to JUUL and similarly acidified nicotine salt e-liquids did not affect platelet aggregation rate. Despite lack of heating coil, the USONICIG under airflow conditions heated e-liquid to ~77°C. CONCLUSIONS:A wide range of ENDS, including multiple types of e-cigarettes with and without nicotine, a heated tobacco product, and an ultrasonic vaping device devoid of heating coil, all impair FMD after a single vaping session comparably to combusted cigarettes. IMPLICATIONS:The need to understand the cardiovascular effects of various ENDS is of timely importance, as we have seen a dramatic increase in the use of these products in recent years, along with the growing assumption among its users that these devices are relatively benign. Our conclusion that a single exposure to aerosol from a wide range of ENDS impairs endothelial function comparably to cigarettes indicates that vaping can cause similar acute vascular functional impairment to smoking and is not a harmless activity.

BACKGROUND:Exposure to tobacco or marijuana smoke, or e-cigarette aerosols, causes vascular endothelial dysfunction in humans and rats. We aimed to determine what constituent, or class of constituents, of smoke is responsible for endothelial functional impairment. METHODS:We investigated several smoke constituents that we hypothesized to mediate this effect by exposing rats and measuring arterial flow-mediated dilation (FMD) pre- and post-exposure. We measured FMD before and after inhalation of sidestream smoke from research cigarettes containing normal and reduced nicotine level with and without menthol, as well as 2 of the main aldehyde gases found in both smoke and e-cigarette aerosol (acrolein and acetaldehyde), and inert carbon nanoparticles. RESULTS:FMD was reduced by all 4 kinds of research cigarettes, with extent of reduction ranging from 20% to 46% depending on the cigarette type. While nicotine was not required for the impairment, higher nicotine levels in smoke were associated with a greater percent reduction of FMD (41.1±4.5% reduction versus 19.2±9.5%; P=0.047). Lower menthol levels were also associated with a greater percent reduction of FMD (18.5±9.8% versus 40.5±4.8%; P=0.048). Inhalation of acrolein or acetaldehyde gases at smoke-relevant concentrations impaired FMD by roughly 50% (P=0.001). However, inhalation of inert carbon nanoparticles at smoke-relevant concentrations with no gas phase also impaired FMD by a comparable amount (P<0.001). Bilateral cervical vagotomy blocked the impairment of FMD by tobacco smoke. CONCLUSIONS:There is no single constituent or class of constituents responsible for acute impairment of endothelial function by smoke; rather, we propose that acute endothelial dysfunction by disparate inhaled products is caused by vagus nerve signaling initiated by airway irritation.

Tobacco and marijuana smoke contains ~7,000 chemicals that cause disorders in cardiac autonomic function, vascular biology, and platelet function. Along with marijuana, e-cigarettes (e-cigs) and heat-not-burn tobacco products (e.g., IQOS) are often viewed as being less harmful than smoking tobacco. However, there are many unknowns about how marijuana, e-cigs, and IQOS impact cardiovascular physiology and platelet function over the long term. To explore cardiovascular effects of smoking/vaping, we exposed conscious rats to single (one time) and multiple (one time daily for 10 days) pulsatile mainstream smoking/vaping of e-cigs (JUUL), IQOS (American and Russian HeatSticks), marijuana (~10% THC), and cannabinoid-depleted (“placebo”) marijuana, relative to regular tobacco (Marlboro Red) smoking and air controls. Cardiac function was assessed by echocardiography pre- and post- single exposure. Platelet aggregation was measured to determine changes in platelet response immediately post-single exposure and one day after the last of multiple exposures. Single exposure induced acute effects on echocardiographic function with reduced ventricular end-diastolic volume (EDV) in IQOS and marijuana groups of both genders (Fig. A), potentially indicating incomplete ventricular relaxation between heart beats after exposure. However, marijuana caused adjustments of end-systolic volume (ESV) and EDV without changes in ejection fraction (EF) in females, with smaller ESV and reduced EDV. Tobacco, marijuana, and placebo marijuana smoking immediately increased collagen-induced platelet aggregation post-single exposure in female rats. Tobacco smoking, JUUL, IQOS, and both kinds of marijuana significantly increased platelet aggregation post-multiple exposure as compared to air controls in mixed genders (Fig. B). P values ≤ 0.1 are shown. Conclusion: smoking/vaping causes clinically relevant adverse effects on cardiac function and platelet aggregation.

Pathogenicity of cardiovascular disease (CVD) from smoking tobacco is well-known, but the CVD effects of vaping non-combustible tobacco products like e-cigarettes and heat-not-burn products (e.g., IQOS), and smoking marijuana (MJ), are less studied. We asked if 8 weeks of chronic use of e-cigs, IQOS, or MJ in rats would cause less adverse cardiac effects than tobacco cigarettes. We exposed SD rats to 1 session/day (10 puffs over 5 min) for 8 weeks with Marlboro Red cigarettes (Cig), JUUL, IQOS, 10% THC MJ (MJ), cannabinoid-depleted “placebo” MJ (pb-MJ), or air. We performed echocardiography and measured conscious systolic blood pressure (SBP) every 2 weeks. We then performed 24-hour conscious ECG telemetry and ex vivo optical mapping (OM) of arrhythmias and analyzed interstitial fibrosis. By 1 hour after exposure, SBP was acutely increased by all tobacco products and pb-MJ, while only marijuana reduced SBP. SBP of all non-air groups rose progressively over 8 weeks, exceeding 130 mmHg after 2 weeks, and 140 mmHg after 4 weeks. SBP increased by MJ was higher than those by JUUL, IQOS, or pb-MJ. Cardiac performance declined and ventricular mass increased. All non-air conditions led to reduced overall heart rate variability, including the total power, low and high frequency from the power spectrum, and SDNN, RMSSD, and NN9 from time-domain method. Poincaré plot suggested a similar distribution pattern of RR interval. Interestingly, when compared with air, reduced physical activity was found in all experimental groups. OM revealed that more arrhythmias were induced by electrical stimulation: Cig, JUUL, IQOS, pb-MJ, MJ had atrial fibrillation of 50%, 85.71%, 50%, 50%, 37.5% and left ventricular (LV) tachycardia of 62.5%, 71.43%, 37.5%, 37.5%, 75% respectively vs. 0% in air, P < .05. Sirius red fibrotic staining showed significantly more interstitial fibrosis of atria and LV in all groups compared to air. Although no significant difference in interstitial fibrosis was found among tobacco products, MJ promoted more LV fibrosis than pb-MJ. Therefore, the use of different non-cigarette tobacco products and marijuana can increase CVD risks by causing hypertension, reduced cardiac performance, increased LV hypertrophy, and susceptibility to arrhythmias.

Introduction: A growing body of research has linked e-cigarette (e-cig) use and vascular dysfunction. However, the molecular mechanism of endothelial function impairment from e-cig use is relatively unknown. We investigated how e-cig use affects endothelial permeability and its regulation by the receptor for advanced glycation end products (RAGE) pathway. Hypothesis: E-cig use increases endothelial permeability compared to both cigarette users and non-users via increasing ligands of RAGE. Methods: We recruited 120 healthy participants who either chronically use e-cigs (n=42), cigarettes (n=28), or no products (n=50), with no dual users. Serum levels of the RAGE ligand subunit S100A8 and the complete RAGE ligand calprotectin were quantified by Luminex and ELISA. Endothelial permeability was measured in cultured human lung microvascular endothelial cells (HMVEC-Ls) that were incubated in all participants’ sera individually by using electric cell-substrate impedance sensing (ECIS). 1 ug/mL of FPS-ZM1 (RAGE inhibitor) and TAK-242 (TLR4 inhibitor) diluted in DMSO were administered to HMVEC-Ls with individual sera. 200 pg/mL of calprotectin and DMSO were administered as positive and negative controls. Results: Incubation of HMVEC-Ls with e-cig users’ sera significantly increased endothelial permeability compared to sera from cigarette smokers and non-users. There was no significant difference in calprotectin serum levels, but S100A8 level was significantly and substantially higher in e-cig users’ sera than in smokers’ and non-user’s sera. Inhibition of RAGE, but not of TLR4, significantly reduced permeability only in e-cig users’ sera compared to vehicle. Conclusions: Endothelial permeability resulting from e-cig use relies on activation of the RAGE pathway and can be partially prevented by inhibition of RAGE.

Background: We reported that permeability of cultured microvascular endothelial cells is increased by incubation in e-cigarette (e-cig) users’ serum relative to that from smokers or non-users. It is unclear whether this is a direct effect of aerosol chemicals that reach the circulation, or an indirect response mediated by the e-cig users’ pulmonary epithelium. Hypothesis: Vaping increases microvascular endothelial permeability indirectly by signaling from alveolar epithelium. Methods: E-cig aerosol condensates were derived from e-liquids with and without nicotine (12 mg/mL free base), each containing menthol, vanillin, ethyl maltol, or cinnamaldehyde (2 mg/mL). Cell permeability was measured in human lung microvascular endothelial cells (HMVEC-Ls) using electric cell-substrate impedance sensing. Human Type II lung alveolar epithelial cells (ATII) were grown in serum-free air-liquid interface and exposed to e-cig aerosols with 0, 18, or 36 mg/mL nicotine (free base and salt), or air, 1 h/day for 3 days in an exposure chamber inside a CO 2 incubator. Results: Incubation of HMVEC-Ls with 0.3% v/v e-cig aerosol condensates from most e-liquids, with and without nicotine, decreased cell permeability (in contrast to the increased permeability that we reported from incubation with e-cig user serum). The exception was menthol + nicotine, which increased permeability (but reduced viability). When HMVEC-Ls were instead incubated with supernatant collected from ATII cells after exposure to e-cig aerosols, permeability was increased when supernatants were from exposure to aerosol with 36 mg/ml nicotine salt, but not 36 or 18 mg/mL freebase nicotine. Supernatants from similarly exposed ATII cells contained higher levels of the proinflammatory proteins MCP-1, IL-8, GROα, and MIP-1β when aerosol contained 36 mg/mL freebase nicotine (3/6 wells) or nicotine salt (5/6), but not 18 mg/ml nicotine (0/6). Conclusion: HVMEC-L permeability was not directly increased by e-cig aerosol condensate, but was increased by supernatant of alveolar epithelial cells exposed to high-nicotine aerosol, potentially mediated by elevated ATII cytokine production, indicating a potential indirect mechanism by which vaping increases pulmonary microvascular permeability.

Introduction: Exposure to tobacco and marijuana smoke impairs vascular endothelial function. While the particulate phase of smoke is heavily implicated, the role of volatile constituents is unclear. Smoke contains aldehydes, which are known to cause endothelial dysfunction. We explored whether two aldehydes found in smoke, acrolein and acetaldehyde, can induce endothelial dysfunction. Hypothesis: Aldehydes in smoke impair endothelial function. Methods: We exposed 4 groups of anesthetized rats to 3 ppm acrolein and 10-11.5 ppm acetaldehyde gases (concentrations relevant to levels in secondhand smoke), Marlboro Red cigarette sidestream smoke at modest levels (600 μg/m 3 PM2.5) as a positive control, and clean air through the gas generation system as a negative control. Exposure was continuous for 10 minutes. Endothelial function (flow-mediated dilation; FMD) was quantified pre- and post-exposure by measuring femoral artery diameter with ultrasound before and after 5 min of transient ischemia and expressed as % vasodilation. Results: Impairment of FMD was observed for acrolein (10.8±1.7(SD)% vs. 5.8±2.9%, p=.001), acetaldehyde (8.8±2.0% vs. 6.0±2.5%, p=.001), and cigarette smoke (9.4±2.9% vs. 5.8±2.0%, p=.002), but not for air (7.9±2.0% vs. 9±3.2%, p=.44) (figure; each colored line denotes a rat pre- and post-exposure; bars denote means). Conclusions: Acrolein and acetaldehyde at levels found in secondhand smoke impair endothelial function. Our results suggest that despite a potential role of particles, volatile aldehydes may mediate part of the endothelial dysfunction caused by exposure to smoke.

Background: Extensive literature supports the harmful effects of cigarette smoke and its constituents on endothelial cells, but the effect of long-term electronic cigarette (e-cig) use on endotheli...

Implantation of bone marrow-derived cells (BMCs) into mouse hearts post-myocardial infarction (MI) limits cardiac functional decline. However, clinical trials of post-MI BMC therapy have yielded conflicting results. While most laboratory experiments use healthy BMC donor mice, clinical trials use post-MI autologous BMCs. Post-MI mouse BMCs are therapeutically impaired, due to inflammatory changes in BMC composition. Thus, therapeutic efficacy of the BMCs progressively worsens after MI but recovers as donor inflammatory response resolves. The availability of post-MI patient BM mononuclear cells (MNCs) from the TIME and LateTIME clinical trials enabled us to test if human post-MI MNCs undergo a similar period of impaired efficacy. We hypothesized that MNCs from TIME trial patients would be less therapeutic than healthy human donor MNCs when implanted into post-MI mouse hearts, and that therapeutic properties would be restored in MNCs from LateTIME trial patients. Post-MI SCID mice received MNCs from healthy donors, TIME patients, or LateTIME patients. Cardiac function improved considerably in the healthy donor group, but neither the TIME nor LateTIME group showed therapeutic effect. Conclusion: post-MI human MNCs lack therapeutic benefits possessed by healthy MNCs, which may partially explain why BMC clinical trials have been less successful than mouse studies.

Background: Smoking cigarettes decreases expression of eNOS in the endothelium, resulting in lower nitric oxide (NO) secretion and decreased flow-mediated dilation in the conducting arteries. In contrast, the effects of e-cigarettes (e-cigs) on endothelial function are just beginning to be studied and the mechanisms of action are unclear. Aim: To test the hypothesis that circulating factors from e-cigarette users decrease endothelial eNOS protein levels and NO secretion in primary endothelial cell cultures, relative to nonsmokers and cigarette smokers. Methods: 36 healthy individuals were recruited and grouped as nonsmokers (n=12), cigarette smokers (n=7), and e-cig users (n=17). Human umbilical vein endothelial cells (HUVECs) were cultured at 20,000 cells per well in 24-well culture plate. Serum samples from individual subjects and endothelial growth media were added at a 1:1 ratio to confluent cells and incubated for 12 hours (basal condition), followed by fresh medium containing VEGF at 50 ng/ml for 30 min (stimulated condition). The amount of NO liberated from cells was measured in culture supernatants by the chemilumin- escence method using a NO analyzer. Endothelial NO synthase (eNOS) protein levels in HUVECs was measured in cell lysates by ELISA. NO and eNOS results were normalized to cell number. Results: The cells treated with serum from e-cig users vs. nonsmokers produced less NO upon stimulation (P<.03) and contained less eNOS protein (P<.03). eNOS protein level was lower in the e-cig user serum group than in the cigarette smoker serum group (P<.05), although stimulated NO production was decreased less by e-cig user serum than by smoker serum. Lower eNOS levels in the cigarette group vs. non-smoker group was not significant, but stimulated NO was significantly lower in the cigarette group vs. nonsmoker (P<.006; see figure). Conclusion: Exposure of cultured endothelial cells to circulating factors from e-cig users, relative to non-users, leads to lower eNOS protein levels and decreased NO production.