1
|
Christen SE, Hermann L, Bekka E, Vonwyl C, Hammann F, van der Velpen V, Eap CB, Benowitz NL, Haschke M, Liakoni E. Pharmacokinetics and Pharmacodynamics of Inhaled Nicotine Salt and Free-Base Using an E-cigarette: A Randomized Crossover Study. Nicotine Tob Res 2024; 26:1313-1321. [PMID: 38597729 PMCID: PMC11417154 DOI: 10.1093/ntr/ntae074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 01/16/2024] [Accepted: 04/08/2024] [Indexed: 04/11/2024]
Abstract
INTRODUCTION Popular "pod-style" e-cigarettes commonly use nicotine salt-based e-liquids that cause less irritation when inhaled and can deliver higher nicotine concentrations than free-base nicotine. This study investigated the pharmacokinetic and pharmacodynamic effects of different nicotine formulations (salt vs. free-base) and concentrations that might influence systemic nicotine absorption and appeal of e-cigarettes. AIMS AND METHODS In this randomized, double-blind, within-subject crossover study, 20 non-nicotine-naïve participants were switched among three e-liquids (free-base nicotine 20 mg/mL, nicotine salt 20 mg/mL, nicotine salt 40 mg/mL) using a refillable pod system and a standardized vaping protocol (one puff every 30 seconds, 10 puffs total). Serum nicotine concentrations and vital signs were assessed over 180 minutes; direct effects, craving, satisfaction, withdrawal, and respiratory symptoms were measured using questionnaires. CYP2A6 genotypes and the nicotine metabolite ratio were also assessed. RESULTS Eleven (55%) participants were male and the median age was 23.5 years (range 18-67). All three formulations differed significantly in peak serum nicotine concentration (baseline adjusted Cmax, median (range): 12.0 ng/mL (1.6-27.3), 5.4 ng/mL (1.9-18.7), and 3.0 ng/mL (1.3-8.8) for nicotine salt 40 mg/mL, nicotine salt 20 mg/mL and free-base 20 mg/mL, respectively). All groups reached Cmax 2.0-2.5 minutes (median) after their last puff. Differences in subjective effects were not statistically significant. No serious adverse events were observed. CONCLUSIONS Free-base 20 mg/mL formulations achieved lower blood nicotine concentrations than nicotine salt 20 mg/mL, while 40 mg/mL nicotine salt yielded concentrations similar to cigarette smoking. The findings can inform regulatory policy regarding e-liquids and their potential use in smoking cessation. IMPLICATIONS Nicotine salt formulations inhaled by an e-cigarette led to higher nicotine delivery compared to nicotine-free-base formulations with the same nicotine concentration. These findings should be considered in future regulatory discussions. The 40 mg/mL nicotine salt formulation showed similar nicotine delivery as combustible cigarettes, albeit at concentrations over the maximum limit for e-liquids allowed in the European Union. Nicotine delivery resembling combustible cigarettes might be beneficial for smokers willing to quit to adequately alleviate withdrawal symptoms. However, increased nicotine delivery can also pose a public health risk, raising concerns about abuse liability, especially among youth and nonsmokers.
Collapse
Affiliation(s)
- Samuel E Christen
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Graduate School for Health Sciences, University of Bern, Bern, Switzerland
| | - Laura Hermann
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Elias Bekka
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Celina Vonwyl
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Graduate School for Health Sciences, University of Bern, Bern, Switzerland
| | - Felix Hammann
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Vera van der Velpen
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | - Chin B Eap
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Department of Psychiatry, Centre for Psychiatric Neuroscience, Lausanne University Hospital, University of Lausanne, Prilly, Switzerland
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
- Center for Research and Innovation in Clinical Pharmaceutical Sciences, University of Lausanne, Lausanne, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, University of Lausanne, Lausanne, Switzerland
| | - Neal L Benowitz
- Department of Medicine, University of California at San Francisco, San Francisco, CA, USA
| | - Manuel Haschke
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | - Evangelia Liakoni
- Clinical Pharmacology and Toxicology, Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| |
Collapse
|
2
|
Yu W, Chen Z, Li Y, Jiang S, Zhang L, Shao XM, Xiao D. In utero chronic intermittent nicotine aerosol exposure increases ischemic heart injury in adult offspring via programming of Angiotensin II receptor-derived TGFβ/ROS/Akt signaling pathway. Reprod Toxicol 2024; 128:108650. [PMID: 38945500 DOI: 10.1016/j.reprotox.2024.108650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/13/2024] [Accepted: 06/21/2024] [Indexed: 07/02/2024]
Abstract
BACKGROUND In utero cigarette smoking/nicotine exposure during pregnancy significantly affects fetal development and increases the risk of cardiovascular disease late in life. However, the underlying molecular mechanisms remain largely unknown. We tested the hypothesis that fetal nicotine aerosol exposure reprograms ischemia-sensitive gene expressions, resulting in increased heart susceptibility to ischemic injury and cardiac dysfunction in adulthood. METHODS Pregnant rats were exposed to chronic intermittent nicotine aerosol (CINA) or saline aerosol control from gestational day 4 to day 21. Experiments were performed on 6-month-old adult offspring. RESULTS CINA exposure increased ischemia-induced cardiac injury and cardiac dysfunction compared to the control group, which was associated with over- expression of angiotensin II receptor (ATR) protein in the left ventricle (LV) of adult offspring. Meanwhile, CINA exposure up-regulated cardiac TGF-β/SMADs family proteins in the LV. In addition, CINA exposure enhanced cardiac reactive oxygen species (ROS) production and increased the DNA methylation level. The levels of phosphorylated-Akt were upregulated but LC3B-II/I protein abundances were downregulated in the hearts isolated from the CINA-treated group. CONCLUSION Fetal nicotine aerosol exposure leads to cardiac dysfunction in response to ischemic stimulation in adulthood. Two molecular pathways are implicated. First, fetal CINA exposure elevates cardiac ATR levels, affecting the TGFβ-SMADs pathway. Second, heightened Angiotensin II/ATR signaling triggers ROS production, leading to DNA hypermethylation, p-Akt activation, and autophagy deficiency. These molecular shifts in cardiomyocytes result in the development of a heart ischemia-sensitive phenotype and subsequent dysfunction in adult offspring.
Collapse
Affiliation(s)
- Wansu Yu
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA; Department of Geriatrics, Jiangsu Provincial Key Laboratory of Geriatrics, First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zewen Chen
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA; Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangzhou, China
| | - Yong Li
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Siyi Jiang
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA; Department of Hematology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Lubo Zhang
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Xuesi M Shao
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA
| | - DaLiao Xiao
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| |
Collapse
|
3
|
Vivarelli F, Morosini C, Rullo L, Losapio LM, Lacorte A, Sangiorgi S, Ghini S, Fagiolino I, Franchi P, Lucarini M, Candeletti S, Canistro D, Romualdi P, Paolini M. Effects of unburned tobacco smoke on inflammatory and oxidative mediators in the rat prefrontal cortex. Front Pharmacol 2024; 15:1328917. [PMID: 38333013 PMCID: PMC10851081 DOI: 10.3389/fphar.2024.1328917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/04/2024] [Indexed: 02/10/2024] Open
Abstract
Although the Food and Drug Administration has authorized the marketing of "heat-not-burn" (HnB) electronic cigarettes as a modified risk tobacco product (MRTP), toxicological effects of HnB smoke exposure on the brain are still unexplored. Here, paramagnetic resonance of the prefrontal cortex (PFC) of HnB-exposed rats shows a dramatic increase in reactive radical species (RRS) yield coupled with an inflammatory response mediated by NF-κB-target genes including TNF-α, IL-1β, and IL-6 and the downregulation of peroxisome proliferator-activated receptor (PPAR) alpha and gamma expression. The PFC shows higher levels of 8-hydroxyguanosine, a marker of DNA oxidative damage, along with the activation of antioxidant machinery and DNA repair systems, including xeroderma pigmentosum group C (XPC) protein complex and 8-oxoguanine DNA glycosylase 1. HnB also induces the expression of drug-metabolizing enzymes such as CYP1A1, CYP2A6, CYP2B6, and CYP2E, particularly involved in the biotransformation of nicotine and several carcinogenic agents such as aldehydes and polycyclic aromatic hydrocarbons here recorded in the HnB stick smoke. Taken together, these effects, from disruption of redox homeostasis, inflammation, PPAR manipulation along with enhanced bioactivation of neurotoxicants, and upregulation of cMYC protooncogene to impairment of primary cellular defense mechanisms, suggest a possible increased risk of brain cancer. Although the HnB device reduces the emission of tobacco toxicants, our findings indicate that its consumption may carry a risk of potential adverse health effects, especially in non-smokers so far. Further studies are needed to fully understand the long-term effects of these devices.
Collapse
Affiliation(s)
- Fabio Vivarelli
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Camilla Morosini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Laura Rullo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Loredana Maria Losapio
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Antonio Lacorte
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Stefano Sangiorgi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Severino Ghini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | | | - Paola Franchi
- Department of Chemistry “G. Ciamician”, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Marco Lucarini
- Department of Chemistry “G. Ciamician”, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Sanzio Candeletti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Donatella Canistro
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| | - Moreno Paolini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, Bologna, Italy
| |
Collapse
|
4
|
Han S, Liu C, Chen H, Fu Y, Zhang Y, Miao R, Ren P, Yu P, Shi Z, Tian Y, Wang H, Liu T, Hou H, Hu Q. Pharmacokinetics of freebase nicotine and nicotine salts following subcutaneous administration in male rats. Drug Test Anal 2023; 15:1099-1106. [PMID: 36059224 DOI: 10.1002/dta.3363] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 07/12/2022] [Accepted: 08/28/2022] [Indexed: 11/08/2022]
Abstract
Nicotine lactate, nicotine tartrate, nicotine benzoate, and freebase nicotine (FBN) are four forms of nicotine salt systems that are present in tobacco products. However, few in vivo studies have compared their pharmacological (pK) efficacies, which are important for understanding their roles in the addiction and abuse of tobacco and nicotine products. In this work, the pK of the above nicotine salt systems was studied by subcutaneously injecting their aqueous solutions in rats and obtaining blood samples from the jugular vein. Nicotine levels in the blood were analyzed by LC-MS/MS. The results demonstrated that rapid nicotine absorption occurred in all nicotine systems. Of them, NB had the smallest Tmax , while FBN had the largest Tmax . The nicotine metabolic rate and clearance decreased for FBN, indicating that nicotine retention in the body was higher than for the other three salt-based systems. Compared with nicotine salts, FBN could reach and maintain a higher concentration in the animal model. Additionally, as the benzoic acid ratios increased, the Cmax of the nicotine benzoate (NB) in the plasma decreased. This indicates that the lower the pH, the lower the Cmax . When different concentrations of NB were used, the higher the NB concentration, the greater the Cmax and AUC(0-t) . These results demonstrate that nicotine adsorption by NB in the animal model depended on both pH and concentration. This baseline information could be used to explain different clinical pharmacological observations in humans, though this study only considered the effects of nicotine on pharmacokinetics in vivo.
Collapse
Affiliation(s)
- Shulei Han
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Chuan Liu
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
| | - Huan Chen
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Ya'ning Fu
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Yuan Zhang
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Ruijuan Miao
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Peipei Ren
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Pengpeng Yu
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Zhihao Shi
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Yushan Tian
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Hongjuan Wang
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Tong Liu
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Hongwei Hou
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| | - Qingyuan Hu
- China National Tobacco Quality Supervision and Test Center, Zhengzhou, China
- Key Laboratory of Tobacco Biological Effects, Zhengzhou, China
| |
Collapse
|
5
|
Wen X, Chung MV, Liszewski KA, Todoro LD, Giancarlo EM, Zhang W, Berkelhamer SK, Goniewicz ML. Cigarette Smoking Abstinence Among Pregnant Individuals Using E-Cigarettes or Nicotine Replacement Therapy. JAMA Netw Open 2023; 6:e2330249. [PMID: 37698863 PMCID: PMC10498331 DOI: 10.1001/jamanetworkopen.2023.30249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 07/16/2023] [Indexed: 09/13/2023] Open
Abstract
Importance Smoking cigarettes during pregnancy can impair maternal and child health, and pregnant individuals have increasingly used electronic cigarettes (e-cigarettes) for various reasons, including quitting smoking. Objective To assess smoking abstinence rates among pregnant individuals who used e-cigarettes compared with those who used nicotine replacement therapy (NRT). Design, Setting, and Participants This cohort study is a secondary data analysis of phase 8 of the US Pregnancy Risk Assessment Monitoring System, conducted between 2016 and 2020. Eligible participants included pregnant individuals who smoked combustible cigarettes within the 3 months before pregnancy and either used e-cigarettes or NRT during pregnancy. Data analysis was conducted from March 2022 to April 2023. Exposures Combustible cigarette use within 3 months before pregnancy and use of either e-cigarettes or NRT during pregnancy. Main Outcomes and Measures The primary outcome was the individual's self-reported smoking abstinence status during the last 3 months of pregnancy. Weighted percentages were reported and weighted multivariable logistic regression models were used to examine the association of e-cigarette use vs NRT with smoking abstinence. A propensity score was used to control for confounding by sociodemographics, pregnancy characteristics, prepregnancy smoking intensity, depression, behavioral support, and hookah use. Results The cohort included 1329 pregnant individuals (759 ≥25 years [60.2%]; 766 non-Hispanic White individuals [79.8%]) of whom 781 had an education level of high school or lower (61.4%), and 952 had an annual household income of $48 000 or less (81.5%). Of the 1329 individuals, 890 (unweighted percentage, 67.0%) were existing e-cigarette users, 67 (unweighted percentage, 5.0%) were new e-cigarette users, and 372 (unweighted percentage, 28.0%) were NRT users. Compared with individuals who used NRT during pregnancy, individuals who used e-cigarettes had a higher rate of smoking abstinence in late pregnancy (456 individuals [50.8%] vs 67 individuals [19.4%]; propensity score adjusted odds ratio [OR], 2.47; 95% CI, 1.17-5.20; P = .02). In the secondary analysis stratified by the timing of e-cigarette use initiation, existing users of e-cigarettes who initiated before pregnancy had a higher smoking abstinence rate than NRT users (446 users [53.1%] vs 67 users [19.4%]; adjusted OR, 2.61; 95% CI, 1.23-5.51; P = .01). However, new e-cigarette users who initiated use during pregnancy had a similar smoking abstinence rate in late pregnancy when compared with NRT users (10 users [20.6%] vs 67 users [19.4%]; adjusted OR, 1.13; 95% CI, 0.22-5.87; P = .88). Conclusions and Relevance These findings suggest that individuals who used e-cigarettes during pregnancy had a higher smoking abstinence rate in late pregnancy than individuals who used NRT, especially for those who initiated e-cigarette use before pregnancy, indicating that replacement of cigarettes with e-cigarettes during pregnancy may be a viable strategy for harm reduction.
Collapse
Affiliation(s)
- Xiaozhong Wen
- Division of Behavioral Medicine, Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo
| | - Minseon V. Chung
- Division of Behavioral Medicine, Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo
| | - Kayla A. Liszewski
- Division of Behavioral Medicine, Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo
| | - Lauren D. Todoro
- Division of Behavioral Medicine, Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo
| | - Eve M. Giancarlo
- Division of Behavioral Medicine, Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo
| | - Wenxin Zhang
- Division of Behavioral Medicine, Department of Pediatrics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo
| | | | - Maciej L. Goniewicz
- Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| |
Collapse
|
6
|
Granata S, Canistro D, Vivarelli F, Morosini C, Rullo L, Mercatante D, Rodriguez-Estrada MT, Baracca A, Sgarbi G, Solaini G, Ghini S, Fagiolino I, Sangiorgi S, Paolini M. Potential Harm of IQOS Smoke to Rat Liver. Int J Mol Sci 2023; 24:12462. [PMID: 37569836 PMCID: PMC10419033 DOI: 10.3390/ijms241512462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
The Food and Drug Administration has recently classified the IQOS electronic cigarette as a modified-risk tobacco product. However, IQOS cigarettes still release various harmful constituents typical of conventional cigarettes (CCs), although the concentrations are markedly lower. Here, we investigated the damaging effects of IQOS smoking on the liver. Male Sprague Dawley rats were exposed, whole body, 5 days/week for 4 weeks to IQOS smoke (4 sticks/day), and hepatic xenobiotic metabolism, redox homeostasis and lipidomic profile were investigated. IQOS boosted reactive radicals and generated oxidative stress. Exposure decreased cellular reserves of total glutathione (GSH) but not GSH-dependent antioxidant enzymes. Catalase and xanthine oxidase were greater in the exposed group, as were various hepatic CYP-dependent monooxygenases (CYP2B1/2, CYP1A1, CYP2A1, CYP2E1-linked). Respiratory chain activity was unaltered, while the number of liver mitochondria was increased. IQOS exposure had an impact on the hepatic lipid profile. With regard to the expression of some MAP kinases commonly activated by CC smoking, IQOS increased the p-p38/p38 ratio, while erythroid nuclear transcription factor 2 (Nrf2) was negatively affected. Our data suggest that IQOS significantly impairs liver function, supporting the precautionary stance taken by the WHO toward the use of these devices, especially by young people and pregnant women.
Collapse
Affiliation(s)
- Silvia Granata
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
- Department of Medicine and Surgery, University of Milan–Bicocca, Via Cadore 48, 20900 Monza, Italy
| | - Donatella Canistro
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
| | - Fabio Vivarelli
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
| | - Camilla Morosini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
| | - Laura Rullo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
| | - Dario Mercatante
- Department of Agricultural and Food Sciences, Alma Mater Studiorum, University of Bologna, Viale Giuseppe Fanin, 40-50, 40127 Bologna, Italy; (D.M.); (M.T.R.-E.)
| | - Maria Teresa Rodriguez-Estrada
- Department of Agricultural and Food Sciences, Alma Mater Studiorum, University of Bologna, Viale Giuseppe Fanin, 40-50, 40127 Bologna, Italy; (D.M.); (M.T.R.-E.)
- Inter-Departmental Centre for Agri-Food Industrial Research, Alma Mater Studiorum, University of Bologna, Via Quinto Bucci 336, 47521 Cesena, Italy
| | - Alessandra Baracca
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio, 48, 40126 Bologna, Italy; (A.B.); (G.S.); (G.S.)
| | - Gianluca Sgarbi
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio, 48, 40126 Bologna, Italy; (A.B.); (G.S.); (G.S.)
| | - Giancarlo Solaini
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Via Irnerio, 48, 40126 Bologna, Italy; (A.B.); (G.S.); (G.S.)
| | - Severino Ghini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
| | - Ivan Fagiolino
- Gruppo CSA—S.p.A., Via al Torrente 22, 47923 Rimini, Italy;
| | - Stefano Sangiorgi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
| | - Moreno Paolini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy; (S.G.); (D.C.); (C.M.); (L.R.); (S.G.); (S.S.); (M.P.)
| |
Collapse
|
7
|
Alkhlaif Y, Shelton KL. Assessment of Abuse-Related Discriminative Stimulus Effects of Nicotine Aerosol in Rodents. J Pharmacol Exp Ther 2023; 385:171-179. [PMID: 36918277 PMCID: PMC10201579 DOI: 10.1124/jpet.122.001520] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/30/2023] [Accepted: 02/24/2023] [Indexed: 03/16/2023] Open
Abstract
The rapid increase in e-cigarette use highlights the importance of developing relevant, predictive animal models exploring their potential health implications. The goal of the present study was to examine the abuse-related effects of brief, repeated e-cigarette aerosol exposures in rodents modeling human e-cigarette user behavior. We evaluated the discriminative stimulus effects of brief, repeated puffs of inhaled nicotine in rats that had been trained to discriminate injected nicotine from saline. Locomotor activity measurement following exposure to injected and aerosolized nicotine was also assessed as an additional behavioral outcome. We hypothesized that the stimulus effects of nicotine aerosol were central nervous system (CNS)-mediated and comparable to that produced by an injected nicotine training stimulus. We further hypothesized that number of aerosol puffs and the e-liquid nicotine concentration which was aerosolized would impact the substitution of nicotine aerosol for injected nicotine. Both nicotine injections and exposures to nicotine aerosol produced a dose-dependent effect on locomotor activity. Nicotine aerosol under our puffing conditions produced e-liquid nicotine concentration-dependent and puff-number-dependent complete substitution for the injected nicotine training condition. The nicotinic antagonist, mecamylamine, completely blocked nicotine-appropriate responding produce by the training dose of 0.3 mg/kg injected nicotine as well as that resulting from exposure to aerosol puffs generated by e-liquid containing 3 mg/ml nicotine, demonstrating that the stimulus of inhaled nicotine was most likely CNS-mediated and not due to olfactory stimulus properties. Overall, the results support the hypothesis that an aerosol exposure drug discrimination model in rodents has applicability to studying the abuse-related effects of e-cigarettes. SIGNIFICANCE STATEMENT: Animal models of nicotine aerosol exposure using testing conditions resembling human e-cigarette use are lacking. In this study, we test a novel preclinical model of nicotine vaping in rodents which allows for the exploration of the abuse-related effects of e-cigarettes. This model has the potential to contribute both to our understanding of the abuse-related pharmacological effects of e-cigarettes as well as aid in the development of rationale, evidence-based e-cigarette regulatory policies.
Collapse
Affiliation(s)
- Yasmin Alkhlaif
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
| | - Keith L Shelton
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
| |
Collapse
|
8
|
Johnson NL, Patten T, Ma M, De Biasi M, Wesson DW. Chemosensory Contributions of E-Cigarette Additives on Nicotine Use. Front Neurosci 2022; 16:893587. [PMID: 35928010 PMCID: PMC9344001 DOI: 10.3389/fnins.2022.893587] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
While rates of smoking combustible cigarettes in the United States have trended down in recent years, use of electronic cigarettes (e-cigarettes) has dramatically increased, especially among adolescents. The vast majority of e-cigarette users consume "flavored" products that contain a variety of chemosensory-rich additives, and recent literature suggests that these additives have led to the current "teen vaping epidemic." This review, covering research from both human and rodent models, provides a comprehensive overview of the sensory implications of e-cigarette additives and what is currently known about their impact on nicotine use. In doing so, we specifically address the oronasal sensory contributions of e-cigarette additives. Finally, we summarize the existing gaps in the field and highlight future directions needed to better understand the powerful influence of these additives on nicotine use.
Collapse
Affiliation(s)
- Natalie L. Johnson
- Department of Pharmacology and Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States
| | - Theresa Patten
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Minghong Ma
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Mariella De Biasi
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Daniel W. Wesson
- Department of Pharmacology and Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, University of Florida, Gainesville, FL, United States
| |
Collapse
|
9
|
De Luca SN, Brassington K, Chan SMH, Dobric A, Mou K, Seow HJ, Vlahos R. Ebselen prevents cigarette smoke-induced cognitive dysfunction in mice by preserving hippocampal synaptophysin expression. J Neuroinflammation 2022; 19:72. [PMID: 35351173 PMCID: PMC8966248 DOI: 10.1186/s12974-022-02432-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/13/2022] [Indexed: 11/26/2022] Open
Abstract
Background Cigarette smoking (CS) is the leading cause of chronic obstructive pulmonary disease (COPD). The “spill-over” of pulmonary inflammation into the systemic circulation may damage the brain, leading to cognitive dysfunction. Cessation of CS can improve pulmonary and neurocognitive outcomes, however, its benefit on the neuroinflammatory profile remains uncertain. Here, we investigate how CS exposure impairs neurocognition and whether this can be reversed with CS cessation or an antioxidant treatment. Methods Male BALB/c mice were exposed to CS (9 cigarettes/day for 8 weeks) followed by 4 weeks of CS cessation. Another cohort of CS-exposed mice were co-administrated with a glutathione peroxidase mimetic, ebselen (10 mg/kg) or vehicle (5% CM-cellulose). We assessed pulmonary inflammation, spatial and working memory, and the hippocampal microglial, oxidative and synaptic profiles. Results CS exposure increased lung inflammation which was reduced following CS cessation. CS caused spatial and working memory impairments which were attributed to hippocampal microglial activation and suppression of synaptophysin. CS cessation did not improve memory deficits or alter microglial activation. Ebselen completely prevented the CS-induced working and spatial memory impairments, which was associated with restored synaptophysin expression without altering microglial activation. Conclusion We were able to model the CS-induced memory impairment and microglial activation seen in human COPD. The preventative effects of ebselen on memory impairment is likely to be dependent on a preserved synaptogenic profile. Cessation alone also appears to be insufficient in correcting the memory impairment, suggesting the importance of incorporating antioxidant therapy to help maximising the benefit of cessation.
Collapse
|
10
|
Lu L, Xiang M, Lu H, Tian Z, Gao Y. Progress in quantification of nicotine content and form distribution in electronic cigarette liquids and aerosols. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2022; 14:359-377. [PMID: 35037007 DOI: 10.1039/d1ay01679b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Each electronic cigarette (e-cigarette) is a battery-powered system which converts electronic cigarette liquids (e-liquids) into the inhalable phase by heating the solution when it is in use. After four generations of development, e-cigarettes tend to be more customized and user-operable. The main components in the e-liquid and the aerosol are vegetable glycerin, propylene glycol, nicotine, organic acid and some flavor ingredients. Among them, nicotine is closely associated with the irritation and physiological satisfaction caused by tobacco products, and it is the core functional substance of e-cigarettes. For this reason, the quantification of nicotine content and nicotine form distribution mainly focuses on the components of the e-liquid and the released aerosol. Up to now, various technologies and methods have been applied in the analysis and research of nicotine content and nicotine form distribution in the e-liquid and its aerosol. GC-MS is often used as the most viable tool for the analysis of volatile organic compounds and can be widely applied in the measurement of nicotine related chemicals; there are a number of quantitation strategies using LC-MS, LC-MS/MS or 1H NMR for the analysis of e-cigarette samples. We also reviewed the four main methods for determining the distribution of nicotine forms, which are pH value derivation, solvent extraction, SPME and NMR methods. These research methods are of great significance to the upgrading and development of e-cigarette products.
Collapse
Affiliation(s)
- Lehua Lu
- Shanghai New Tobacco Product Research Institute, Xiupu Road 3733, Shanghai 201315, China.
| | - Menghui Xiang
- School of Chemical Science & Engineering, Shanghai Key Laboratory of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China.
| | - Haoran Lu
- School of Chemical Science & Engineering, Shanghai Key Laboratory of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China.
| | - Zhixin Tian
- School of Chemical Science & Engineering, Shanghai Key Laboratory of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, China.
| | - Yihan Gao
- Shanghai New Tobacco Product Research Institute, Xiupu Road 3733, Shanghai 201315, China.
| |
Collapse
|
11
|
Vivarelli F, Canistro D, Cirillo S, Elias RJ, Granata S, Mussoni M, Burattini S, Falcieri E, Turrini E, Fimognari C, Buschini A, Lazzaretti M, Beghi S, Girotti S, Sangiorgi S, Bolelli L, Ghini S, Ferri EN, Fagiolino I, Franchi P, Lucarini M, Mercatante D, Rodriguez-Estrada MT, Lorenzini A, Marchionni S, Gabriele M, Longo V, Paolini M. Unburned Tobacco Cigarette Smoke Alters Rat Ultrastructural Lung Airways and DNA. Nicotine Tob Res 2021; 23:2127-2134. [PMID: 34036368 DOI: 10.1093/ntr/ntab108] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/20/2021] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Recently, the Food and Drug Administration authorized the marketing of IQOS Tobacco Heating System as a Modified Risk Tobacco Product based on an electronic heat-not-burn technology that purports to reduce the risk. METHODS Sprague-Dawley rats were exposed in a whole-body mode to IQOS aerosol for 4 weeks. We performed the chemical characterization of IQOS mainstream and we studied the ultrastructural changes in trachea and lung parenchyma of rats exposed to IQOS stick mainstream and tissue pro-inflammatory markers. We investigated the reactive oxygen species amount along with the markers of tissue and DNA oxidative damage. Moreover, we tested the putative genotoxicity of IQOS mainstream through Ames and alkaline Comet mutagenicity assays. RESULTS Here, we identified irritating and carcinogenic compounds including aldehydes and polycyclic aromatic hydrocarbons in the IQOS mainstream as sign of incomplete combustion and degradation of tobacco, that lead to severe remodelling of smaller and largest rat airways. We demonstrated that IQOS mainstream induces lung enzymes that activate carcinogens, increases tissue reactive radical concentration; promotes oxidative DNA breaks and gene level DNA damage; and stimulates mitogen activated protein kinase pathway which is involved in the conventional tobacco smoke-induced cancer progression. CONCLUSIONS Collectively, our findings reveal that IQOS causes grave lung damage and promotes factors that increase cancer risk. IMPLICATIONS IQOS has been proposed as a safer alternative to conventional cigarettes, due to depressed concentration of various harmful constituents typical of traditional tobacco smoke. However, its lower health risks to consumers have yet to be determined. Our findings confirm that IQOS mainstream contains pyrolysis and thermogenic degradation by-products, the same harmful constituents of traditional cigarette smoke, and, for the first time, we show that it causes grave lung damage and promotes factors that increase cancer risk in the animal model.
Collapse
Affiliation(s)
- Fabio Vivarelli
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Donatella Canistro
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Silvia Cirillo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Ryan J Elias
- Department of Food Science, College of Agricultural Sciences, Pennsylvania State University, University Park, PA, USA
| | - Silvia Granata
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Matilde Mussoni
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Sabrina Burattini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Elisabetta Falcieri
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Eleonora Turrini
- Department for Life Quality Studies, Alma Mater Studiorum-University of Bologna, Rimini, Italy
| | - Carmela Fimognari
- Department for Life Quality Studies, Alma Mater Studiorum-University of Bologna, Rimini, Italy
| | - Annamaria Buschini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Mirca Lazzaretti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Sofia Beghi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Stefano Girotti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Stefano Sangiorgi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Luca Bolelli
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Severino Ghini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Elida Nora Ferri
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | | | - Paola Franchi
- Department of Chemistry "G. Ciamician," Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Marco Lucarini
- Department of Chemistry "G. Ciamician," Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Dario Mercatante
- Department of Agricultural and Food Sciences, Alma Mater Studiorum-University di Bologna, Bologna, Italy
| | - Maria Teresa Rodriguez-Estrada
- Department of Agricultural and Food Sciences, Alma Mater Studiorum-University di Bologna, Bologna, Italy
- Inter-Departmental Centre for Agri-Food Industrial Research, Alma Mater Studiorum-University of Bologna, Cesena, Italy
| | - Antonello Lorenzini
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Silvia Marchionni
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| | - Morena Gabriele
- Department of Agricultural Biology and Biotechnology, CNR, Pisa, Italy
| | - Vincenzo Longo
- Department of Agricultural Biology and Biotechnology, CNR, Pisa, Italy
| | - Moreno Paolini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna,Italy
| |
Collapse
|
12
|
Adverse effects of fetal exposure of electronic-cigarettes and high-fat diet on male neonatal hearts. Exp Mol Pathol 2020; 118:104573. [PMID: 33212125 PMCID: PMC8501912 DOI: 10.1016/j.yexmp.2020.104573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 10/30/2020] [Accepted: 11/11/2020] [Indexed: 11/21/2022]
Abstract
Epidemiological studies have shown an increased risk of cardiovascular diseases in children born to mothers who smoked during pregnancy. The cardiovascular risk in the offspring associated with in utero nicotine exposure is further exaggerated by maternal obesity. The consumption of electronic cigarettes (e-cigarettes) is alarmingly increasing among adolescents and young adults without the knowledge of their harmful health effects. There has also been a substantial increase in e-cigarette use by women of reproductive age. This study investigates the detrimental effects of gestational exposure of e-cigarette and a high-fat diet (HFD) on neonatal hearts. Time-mated pregnant mice were fed a HFD and exposed to saline or e-cigarette aerosol with 2.4% nicotine from embryonic day 4 (E4) to E20. We demonstrated that in utero exposure of e-cigarettes and HFD from E4 to E20 triggers cardiomyocyte (CM) apoptosis in the offspring at postnatal day1 (PND1), PND3, and PND14. Induction of CM apoptosis following gestational exposure of e-cigarettes and HFD was associated with inactivation of AMP-activated protein kinase (AMPK), increased cardiac oxidative stress coupled with perturbation of cardiac BAX/ BCL-2 ratio and activation of caspase 3 at PND 14. Electron microscopy further revealed that left ventricles of pups at PND14 after e-cigarette exposure exhibited apoptotic nuclei, convoluted nuclear membranes, myofibrillar derangement, and enlarged mitochondria occasionally showing signs of crystolysis, indicative of cardiomyopathy and cardiac dysfunction. Our results show profound adverse effects of prenatal exposure of e-cigarette plus HFD in neonatal hearts that may lead to long-term adverse cardiac consequences in the adult.
Collapse
|
13
|
Gholap VV, Kosmider L, Golshahi L, Halquist MS. Nicotine forms: why and how do they matter in nicotine delivery from electronic cigarettes? Expert Opin Drug Deliv 2020; 17:1727-1736. [PMID: 32842785 DOI: 10.1080/17425247.2020.1814736] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Unregulated e-cigarette devices and their nicotine content have amplified the potential of e-cigarettes as addictive agents. Several e-cigarette-related parameters have been identified altering nicotine's absorption profile, so their potential effects on addiction should be considered. Of these factors, nicotine forms (protonated and free base) play a significant role in the addiction potential yet their impact on nicotine's absorption has been studied with limited research. AREAS COVERED Current review aims to emphasize on the possible mechanism behind different absorption profiles of nicotine forms considering their physical states (droplet and vapor phase) and the aerosol particle size, their analysis in e-cigarette research and the regulatory attention warranted by them to combat nicotine addiction in the population due to e-cigarettes. EXPERT OPINION The protonated form of nicotine is being correlated with the smooth sensory effects and high nicotine absorption as compared to free base nicotine. With the introduction of nicotine salts, which yield mostly the protonated form, the youth popularity of e-cigarettes has spiked exponentially. While it is important to control nicotine levels in e-cigarette products, attention should also be given to the nicotine forms present in these products in order to address nicotine addiction in the population.
Collapse
Affiliation(s)
- Vinit V Gholap
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University , Richmond, Virginia, USA
| | - Leon Kosmider
- Department of General and Inorganic Chemistry, Medical University of Silesia , Sosnowiec, Poland
| | - Laleh Golshahi
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia, USA
| | - Matthew S Halquist
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University , Richmond, Virginia, USA
| |
Collapse
|
14
|
Patten T, De Biasi M. History repeats itself: Role of characterizing flavors on nicotine use and abuse. Neuropharmacology 2020; 177:108162. [PMID: 32497589 DOI: 10.1016/j.neuropharm.2020.108162] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 12/13/2022]
Abstract
The popularity of e-cigarettes has skyrocketed in recent years, and most vapers use flavored e-cigarette products. Consumption of flavored e-cigarettes exceeds that of combustible cigarettes and other tobacco products among adolescents, who are particularly vulnerable to becoming nicotine dependent. Flavorings have been used by the tobacco industry since the 17th century, but the use of flavors by the e-cigarette industry to create products with "characterizing" flavors (i.e. flavors other than tobacco or menthol) has sparked a public health debate. This review addresses the possibility that characterizing flavors make nicotine more appealing, rewarding and addictive. It also discusses ways in which preclinical and clinical studies could improve our understanding of the mechanisms by which flavors may alter nicotine reward and reinforcement. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
Collapse
Affiliation(s)
- Theresa Patten
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Mariella De Biasi
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
| |
Collapse
|
15
|
Ho J, Sciuscio D, Kogel U, Titz B, Leroy P, Vuillaume G, Talikka M, Martin E, Pospisil P, Lebrun S, Xia W, Lee T, Chng YX, Phillips BW, Veljkovic E, Guedj E, Xiang Y, Ivanov NV, Peitsch MC, Hoeng J, Vanscheeuwijck P. Evaluation of toxicity of aerosols from flavored e-liquids in Sprague-Dawley rats in a 90-day OECD inhalation study, complemented by transcriptomics analysis. Arch Toxicol 2020; 94:2179-2206. [PMID: 32367274 PMCID: PMC7303093 DOI: 10.1007/s00204-020-02759-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 04/22/2020] [Indexed: 01/08/2023]
Abstract
The use of flavoring substances is an important element in the development of reduced-risk products for adult smokers to increase product acceptance and encourage switching from cigarettes. In a first step towards characterizing the sub-chronic inhalation toxicity of neat flavoring substances, a study was conducted using a mixture of the substances in a base solution of e-liquid, where the standard toxicological endpoints of the nebulized aerosols were supplemented with transcriptomics analysis. The flavor mixture was produced by grouping 178 flavors into 26 distinct chemical groups based on structural similarities and potential metabolic and biological effects. Flavoring substances predicted to show the highest toxicological effect from each group were selected as the flavor group representatives (FGR). Following Organization for Economic Cooperation and Development Testing Guideline 413, rats were exposed to three concentrations of the FGR mixture in an e-liquid composed of nicotine (23 µg/L), propylene glycol (1520 µg/L), and vegetable glycerin (1890 µg/L), while non-flavored and no-nicotine mixtures were included as references to identify potential additive or synergistic effects between nicotine and the flavoring substances. The results indicated that the inhalation of an e-liquid containing the mixture of FGRs caused very minimal local and systemic toxic effects. In particular, there were no remarkable clinical (in-life) observations in flavored e-liquid-exposed rats. The biological effects related to exposure to the mixture of neat FGRs were limited and mainly nicotine-mediated, including changes in hematological and blood chemistry parameters and organ weight. These results indicate no significant additive biological changes following inhalation exposure to the nebulized FGR mixture above the nicotine effects measured in this sub-chronic inhalation study. In a subsequent study, e-liquids with FGR mixtures will be aerosolized by thermal treatment and assessed for toxicity.
Collapse
Affiliation(s)
- Jenny Ho
- PMI S&I, Philip Morris International Research Laboratories Pte. Ltd., Science Park II, Singapore, Singapore
| | - Davide Sciuscio
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Ulrike Kogel
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Bjoern Titz
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Patrice Leroy
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Gregory Vuillaume
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Marja Talikka
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Elyette Martin
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Pavel Pospisil
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Stefan Lebrun
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Wenhao Xia
- PMI S&I, Philip Morris International Research Laboratories Pte. Ltd., Science Park II, Singapore, Singapore
| | - Tom Lee
- PMI S&I, Philip Morris International Research Laboratories Pte. Ltd., Science Park II, Singapore, Singapore
| | - Yun Xuan Chng
- PMI S&I, Philip Morris International Research Laboratories Pte. Ltd., Science Park II, Singapore, Singapore
| | - Blaine W Phillips
- PMI S&I, Philip Morris International Research Laboratories Pte. Ltd., Science Park II, Singapore, Singapore
| | - Emilija Veljkovic
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Emmanuel Guedj
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Yang Xiang
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Nikolai V Ivanov
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Manuel C Peitsch
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Julia Hoeng
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland
| | - Patrick Vanscheeuwijck
- PMI S&I, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000, Neuchâtel, Switzerland.
| |
Collapse
|
16
|
Gholap VV, Heyder RS, Kosmider L, Halquist MS. An Analytical Perspective on Determination of Free Base Nicotine in E-Liquids. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2020; 2020:6178570. [PMID: 32257508 PMCID: PMC7085884 DOI: 10.1155/2020/6178570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/04/2020] [Indexed: 05/09/2023]
Abstract
In electronic cigarette users, nicotine delivery to lungs depends on various factors. One of the important factors is e-liquid nicotine concentration. Nicotine concentration in e-liquids ranges from 0 to >50 mg/mL. Furthermore, nicotine exists in protonated and unprotonated ("free base") forms. The two forms are believed to affect the nicotine absorption in body. Therefore, in addition to total nicotine concentration, e-liquids should be characterized for their free base nicotine yield. Two approaches are being used for the determination of free base nicotine in e-liquids. The first is applying a dilution to e-liquids followed by two methods: Henderson-Hasselbalch theory application or a Liquid-Liquid Extraction. The second is the without-dilution approach followed by 1H NMR method. Here, we carried out controlled experiments using five e-liquids of different flavors using these two approaches. In the dilution approach, the Henderson-Hasselbalch method was tested using potentiometric titration. The accuracy was found to be >98% for all five e-liquid samples (n = 3). A Liquid-Liquid Extraction was carried out using toluene or hexane as extraction solvent. The Liquid-Liquid Extraction technique was found to be limited by solvent interactions with flavors. Solvent extractions resulted in flavor dependent inaccuracies in free base nicotine determination (5 to 277% of calculated values). The without-dilution approach was carried out using 1H NMR as described by Duell et al. This approach is proposed to offer an independent and alternative scale. None of the methods have established a strong correlation between pre- and postvaporization free base nicotine yield. Here we present comparative results of two approaches using analytical techniques. Such a comparison would be helpful in establishing a standardized method for free base nicotine determination of e-liquids.
Collapse
Affiliation(s)
- Vinit V. Gholap
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond 23298, VA, USA
| | - Rodrigo S. Heyder
- Department of Pharmaceutics, Pharmaceutical Engineering, School of Pharmacy, Virginia Commonwealth University, Richmond 23298, VA, USA
| | - Leon Kosmider
- Department of General and Inorganic Chemistry, Medical University of Silesia, Katowice FOPS in Sosnowiec, Jagiellonska 4, 41-200 Sosnowiec, Poland
| | - Matthew S. Halquist
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond 23298, VA, USA
| |
Collapse
|
17
|
Shao XM, Fang ZT. Severe Acute Toxicity of Inhaled Nicotine and e-Cigarettes. Chest 2020; 157:506-508. [DOI: 10.1016/j.chest.2019.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/05/2019] [Indexed: 11/24/2022] Open
|
18
|
Boué S, Goedertier D, Hoeng J, Iskandar A, Kuczaj AK, Marescotti D, Mathis C, May A, Phillips B, Peitsch MC, Schlage WK, Sciuscio D, Tan WT, Vanscheeuwijck P. State-of-the-art methods and devices for generation, exposure, and collection of aerosols from e-vapor products. TOXICOLOGY RESEARCH AND APPLICATION 2020. [DOI: 10.1177/2397847320979751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
E-vapor products (EVP) have become popular alternatives for cigarette smokers who would otherwise continue to smoke. EVP research is challenging and complex, mostly because of the numerous and rapidly evolving technologies and designs as well as the multiplicity of e-liquid flavors and solvents available on the market. There is an urgent need to standardize all stages of EVP assessment, from the production of a reference product to e-vapor generation methods and from physicochemical characterization methods to nonclinical and clinical exposure studies. The objective of this review is to provide a detailed description of selected experimental setups and methods for EVP aerosol generation and collection and exposure systems for their in vitro and in vivo assessment. The focus is on the specificities of the product that constitute challenges and require development of ad hoc assessment frameworks, equipment, and methods. In so doing, this review aims to support further studies, objective evaluation, comparison, and verification of existing evidence, and, ultimately, formulation of standardized methods for testing EVPs.
Collapse
Affiliation(s)
- Stéphanie Boué
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Didier Goedertier
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Julia Hoeng
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Anita Iskandar
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Arkadiusz K Kuczaj
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Diego Marescotti
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Carole Mathis
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Anne May
- Consultants in Science, Epalinges, Switzerland
| | - Blaine Phillips
- Philip Morris International (PMI) Research & Development, Philip Morris International Research Laboratories Pte. Ltd, Science Park II, Singapore
| | - Manuel C Peitsch
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | | | - Davide Sciuscio
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Wei Teck Tan
- Philip Morris International (PMI) Research & Development, Philip Morris International Research Laboratories Pte. Ltd, Science Park II, Singapore
| | - Patrick Vanscheeuwijck
- Philip Morris International (PMI) Research & Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| |
Collapse
|
19
|
Shao XM, Friedman TC. Pod-mod vs. conventional e-cigarettes: nicotine chemistry, pH, and health effects. J Appl Physiol (1985) 2019; 128:1056-1058. [PMID: 31854246 DOI: 10.1152/japplphysiol.00717.2019] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
- Xuesi M Shao
- Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California
| | - Theodore C Friedman
- Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California
| |
Collapse
|
20
|
A mouse model for chronic intermittent electronic cigarette exposure exhibits nicotine pharmacokinetics resembling human vapers. J Neurosci Methods 2019; 326:108376. [PMID: 31361999 DOI: 10.1016/j.jneumeth.2019.108376] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 02/04/2023]
Abstract
Electronic cigarettes (E-cig) use is increasing rapidly, particularly among youths. Animal models for E-cig exposure with pharmacokinetics resembling human E-cig users are lacking. We developed an E-cig aerosol exposure system for rodents and a chronic intermittent delivery method that simulates E-cig users who vape episodically during wakefulness and abstain during sleep. Mice were exposed to E-cig in a programmed schedule at very low, low, medium, or high doses defined by duration of each puff, number of puffs per delivery episode and frequency of episodes in the dark phase of a 12/12-h circadian cycle for 9 consecutive days. The plasma nicotine/cotinine levels and their time courses were determined using LC/MS-MS. We assessed the body weight, food intake and locomotor activity of Apolipoprotein E null (ApoE-/-) mice exposed to chronic intermittent E-cig aerosol. Plasma nicotine and cotinine levels were positively correlated with exposure doses. Nicotine and cotinine levels showed a circadian variation as they increased with time up to the maximum nicotine level of 21.8 ± 7.1 ng/mL during the daily intermittent E-cig exposure in the 12-h dark phase and then declined during the light phase when there was no E-cig delivery. Chronic E-cig exposure to ApoE-/- mice decreased body weight, food intake and increased locomotion. Our rodent E-cig exposure system and chronic intermittent exposure method yield clinically relevant nicotine pharmacokinetics associated with behavioral and metabolic changes. The methodologies are essential tools for in vivo studies of the health impacts of E-cig exposure on CNS, cardiovascular, pulmonary, hepatic systems, metabolism and carcinogenesis.
Collapse
|
21
|
Espinoza-Derout J, Hasan KM, Shao XM, Jordan MC, Sims C, Lee DL, Sinha S, Simmons Z, Mtume N, Liu Y, Roos KP, Sinha-Hikim AP, Friedman TC. Chronic intermittent electronic cigarette exposure induces cardiac dysfunction and atherosclerosis in apolipoprotein-E knockout mice. Am J Physiol Heart Circ Physiol 2019; 317:H445-H459. [PMID: 31172811 DOI: 10.1152/ajpheart.00738.2018] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Electronic cigarettes (e-cigarettes), also known as electronic nicotine delivery systems, are a popular alternative to conventional nicotine cigarettes, both among smokers and those who have never smoked. In spite of the widespread use of e-cigarettes and the proposed detrimental cardiac and atherosclerotic effects of nicotine, the effects of e-cigarettes on these systems are not known. In this study, we investigated the cardiovascular and cardiac effects of e-cigarettes with and without nicotine in apolipoprotein-E knockout (ApoE-/-) mice. We developed an e-cigarette exposure model that delivers nicotine in a manner similar to that of human e-cigarettes users. Using commercially available e-cigarettes, bluCig PLUS, ApoE-/- mice were exposed to saline, e-cigarette without nicotine [e-cigarette (0%)], and e-cigarette with 2.4% nicotine [e-cigarette (2.4%)] aerosol for 12 wk. Echocardiographic data show that mice treated with e-cigarette (2.4%) had decreased left ventricular fractional shortening and ejection fraction compared with e-cigarette (0%) and saline. Ventricular transcriptomic analysis revealed changes in genes associated with metabolism, circadian rhythm, and inflammation in e-cigarette (2.4%)-treated ApoE-/- mice. Transmission electron microscopy revealed that cardiomyocytes of mice treated with e-cigarette (2.4%) exhibited ultrastructural abnormalities indicative of cardiomyopathy. Additionally, we observed increased oxidative stress and mitochondrial DNA mutations in mice treated with e-cigarette (2.4%). ApoE-/- mice on e-cigarette (2.4%) had also increased atherosclerotic lesions compared with saline aerosol-treated mice. These results demonstrate adverse effects of e-cigarettes on cardiac function in mice.NEW & NOTEWORTHY The present study is the first to show that mice exposed to nicotine electronic cigarettes (e-cigarettes) have decreased cardiac fractional shortening and ejection fraction in comparison with controls. RNA-seq analysis reveals a proinflammatory phenotype induced by e-cigarettes with nicotine. We also found increased atherosclerosis in the aortic root of mice treated with e-cigarettes with nicotine. Our results show that e-cigarettes with nicotine lead to detrimental effects on the heart that should serve as a warning to e-cigarette users and agencies that regulate them.
Collapse
Affiliation(s)
- Jorge Espinoza-Derout
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Kamrul M Hasan
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Xuesi M Shao
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Maria C Jordan
- David Geffen School of Medicine at University of California, Los Angeles, California
| | - Carl Sims
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Desean L Lee
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Satyesh Sinha
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Zena Simmons
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Norma Mtume
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Yanjun Liu
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Kenneth P Roos
- David Geffen School of Medicine at University of California, Los Angeles, California
| | - Amiya P Sinha-Hikim
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| | - Theodore C Friedman
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, California.,David Geffen School of Medicine at University of California, Los Angeles, California
| |
Collapse
|
22
|
Hasan KM, Friedman TC, Shao X, Parveen M, Sims C, Lee DL, Espinoza-Derout J, Sinha-Hikim I, Sinha-Hikim AP. E-cigarettes and Western Diet: Important Metabolic Risk Factors for Hepatic Diseases. Hepatology 2019; 69:2442-2454. [PMID: 30664268 PMCID: PMC6636679 DOI: 10.1002/hep.30512] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 01/15/2019] [Indexed: 01/18/2023]
Abstract
The use of electronic nicotine delivery systems (ENDS), also known as e-cigarettes, with a variety of e-liquids/e-juices, is increasing at an alarming rate among adolescents who do not realize the potential harmful health effects. This study examines the harmful effects of ENDS on the liver. Apolipoprotein E null (ApoE-/-) mice on a western diet (WD) were exposed to saline or ENDS with 2.4% nicotine aerosol for 12 weeks using our mouse ENDS exposure model system, which delivers nicotine to mice and leads to equivalent serum cotinine levels found in human cigarette users. ApoE-/- mice on a WD exposed to ENDS exhibited a marked increase in hepatic lipid accumulation compared with ApoE-/- on a similar diet exposed to saline aerosol. The detrimental effects of ENDS on hepatic steatosis were associated with significantly greater oxidative stress, increased hepatic triglyceride levels, and increased hepatocyte apoptosis, independent of adenosine monophosphate-activated protein kinase signaling. In addition, hepatic RNA sequencing analysis revealed that 433 genes were differentially expressed in ENDS-exposed mice on WD compared with saline-exposed mice. Functional analysis indicates that genes associated with lipid metabolism, cholesterol biosynthesis, and circadian rhythm were most significantly altered in the liver in response to ENDS. Conclusion: These results demonstrate profound adverse effects of ENDS on the liver. This is important information for regulatory agencies as they regulate ENDS.
Collapse
Affiliation(s)
- Kamrul M. Hasan
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059
| | - Theodore C Friedman
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059,,David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
| | - Xuesi Shao
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059,,David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
| | - Meher Parveen
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059
| | - Carl Sims
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059
| | - Desean L. Lee
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059
| | - Jorge Espinoza-Derout
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059
| | - Indrani Sinha-Hikim
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059,,David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
| | - Amiya P. Sinha-Hikim
- Division of Endocrinology, Metabolism and Molecular Medicine, Department of Internal Medicine, Charles R. Drew University, Los Angeles, CA 90059,,David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
| |
Collapse
|
23
|
Shao XM, Liu S, Lee ES, Fung D, Pei H, Liang J, Mudgway R, Zhang J, Feldman JL, Zhu Y, Louie S, Xie XS. Chronic intermittent nicotine delivery via lung alveolar region-targeted aerosol technology produces circadian pharmacokinetics in rats resembling human smokers. J Appl Physiol (1985) 2018; 125:1555-1562. [PMID: 30236046 PMCID: PMC6295479 DOI: 10.1152/japplphysiol.00357.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/18/2018] [Accepted: 09/20/2018] [Indexed: 11/22/2022] Open
Abstract
Cigarette smoke is an aerosol containing microparticles that carry nicotine into the lung alveolar region where nicotine is rapidly absorbed into circulation. Nicotine exposure in smokers is a chronic intermittent process, with episodic intake during wakefulness and abstinence during sleep resulting in circadian fluctuation of blood nicotine levels. We developed an integrated platform where freely moving rodents can be exposed to episodic nicotine aerosol on an investigator-designed schedule. Plasma nicotine and its metabolite cotinine levels were determined with a LC-MS/MS method. We characterized the aerosol in the breathing zone of the rodent exposure chamber. The droplet-size distribution was within the respirable diameter range. The system can generate a wide range of nicotine concentrations in air that meet a variety of experimental needs. Rats were exposed to nicotine aerosol once every half hour in the dark phase of 12:12-h light-dark cycles for 10 days. We optimized the parameters of aerosol generation and exposure: plasma nicotine and cotinine concentrations reached 30-35 and 190-240 ng/ml, respectively. The nicotine levels and circadian patterns resembled the pharmacokinetic pattern of human smokers. In summary, we developed an aerosol system that can produce clinically relevant chronic intermittent nicotine exposure in unanesthetized, unrestrained rodents with route of administration and circadian blood pharmacokinetics resembling human smokers. This methodology is a novel tool for understanding the health effects of chronic intermittent nicotine exposure such as with tobacco cigarettes and electronic cigarettes for studies of behavior, pharmacology and toxicology, nicotine addiction, tobacco-related diseases, and teratogenicity, and for the discovery of therapeutics. NEW & NOTEWORTHY We developed a lung alveolar region-targeted aerosol method and a system that provides chronic intermittent nicotine exposure in freely moving rodents. The method produces in rodents clinically relevant nicotine exposure with the route and circadian pharmacokinetics resembling human smokers. This method is a novel tool for understanding the health impacts of chronic nicotine exposures such as with tobacco cigarettes and electronic cigarettes, for studying nicotine pharmacology, toxicology, addiction, and tobacco-related diseases, and for the discovery of therapeutics.
Collapse
Affiliation(s)
- Xuesi M Shao
- Department of Neurobiology, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Siyu Liu
- Titus Family Department of Clinical Pharmacy, University of Southern California School of Pharmacy , Los Angeles, California
| | - Eon S Lee
- Department of Environmental Health Sciences, UCLA Fielding School of Public Health , Los Angeles, California
| | - David Fung
- Department of Environmental Health Sciences, UCLA Fielding School of Public Health , Los Angeles, California
| | - Hua Pei
- Titus Family Department of Clinical Pharmacy, University of Southern California School of Pharmacy , Los Angeles, California
| | - Jing Liang
- Titus Family Department of Clinical Pharmacy, University of Southern California School of Pharmacy , Los Angeles, California
| | - Ross Mudgway
- Department of Neurobiology, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Jingxi Zhang
- AfaSci Research Laboratories, AfaSci, Incorporated, Redwood City, California
| | - Jack L Feldman
- Department of Neurobiology, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Yifang Zhu
- Department of Environmental Health Sciences, UCLA Fielding School of Public Health , Los Angeles, California
| | - Stan Louie
- Titus Family Department of Clinical Pharmacy, University of Southern California School of Pharmacy , Los Angeles, California
| | - Xinmin S Xie
- AfaSci Research Laboratories, AfaSci, Incorporated, Redwood City, California
| |
Collapse
|
24
|
Ahmad S, Zafar I, Mariappan N, Husain M, Wei CC, Vetal N, Eltoum IA, Ahmad A. Acute pulmonary effects of aerosolized nicotine. Am J Physiol Lung Cell Mol Physiol 2018; 316:L94-L104. [PMID: 30358437 DOI: 10.1152/ajplung.00564.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nicotine is a highly addictive principal component of both tobacco and electronic cigarette that is readily absorbed in blood. Nicotine-containing electronic cigarettes are promoted as a safe alternative to cigarette smoking. However, the isolated effects of inhaled nicotine are largely unknown. Here we report a novel rat model of aerosolized nicotine with a particle size (~1 μm) in the respirable diameter range. Acute nicotine inhalation caused increased pulmonary edema and lung injury as measured by enhanced bronchoalveolar lavage fluid protein, IgM, lung wet-to-dry weight ratio, and high-mobility group box 1 (HMGB1) protein and decreased lung E-cadherin protein. Immunohistochemical analysis revealed congested blood vessels and increased neutrophil infiltration. Lung myeloperoxidase mRNA and protein increased in the nicotine-exposed rats. Complete blood counts also showed an increase in neutrophils, white blood cells, eosinophils, and basophils. Arterial blood gas measurements showed an increase in lactate. Lungs of nicotine-inhaling animals revealed increased mRNA levels of IL-1A and CXCL1. There was also an increase in IL-1α protein. In in vitro air-liquid interface cultures of airway epithelial cells, there was a dose dependent increase in HMGB1 release with nicotine treatment. Air-liquid cultures exposed to nicotine also resulted in a dose-dependent loss of barrier as measured by transepithelial electrical resistance and a decrease in E-cadherin expression. Nicotine also caused a dose-dependent increase in epithelial cell death and an increase in caspase-3/7 activities. These results show that the nicotine content of electronic cigarettes may have adverse pulmonary and systemic effects.
Collapse
Affiliation(s)
- Shama Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Iram Zafar
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Nithya Mariappan
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Maroof Husain
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Chih-Chang Wei
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Nilam Vetal
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Isam A Eltoum
- Department of Pathology, University of Alabama at Birmingham , Birmingham, Alabama
| | - Aftab Ahmad
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| |
Collapse
|
25
|
Inhaled nicotine equivalent to cigarette smoking disrupts systemic and uterine hemodynamics and induces cardiac arrhythmia in pregnant rats. Sci Rep 2017; 7:16974. [PMID: 29209071 PMCID: PMC5717237 DOI: 10.1038/s41598-017-17301-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/23/2017] [Indexed: 01/09/2023] Open
Abstract
Maternal smoking with obligatory nicotine inhalation is associated with preterm delivery, low birth weight, fetal growth retardation and developmental defects. We tested the hypothesis that cigarette smoking-relevant nicotine inhalation during pregnancy impairs cardiovascular function and uterine hemodynamics with consequential fetal ischemia. Pregnant rats exposed to episodic inhaled nicotine via a novel lung alveolar region-targeted aerosol method produced nicotine pharmacokinetics resembling cigarette smoking in humans. This clinically relevant nicotine aerosol inhalation (NAI) induced transient reduction and irregular fluctuations in uterine artery blood flow associated with cardiac arrhythmia and high magnitude irregular fluctuations of systemic blood pressure. The arrhythmia included sinoatrial (SA) block, sinus arrest, 2° and 3° atrioventricular (A-V) block and supraventricular escape rhythm. These effects were blocked by the nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine. Resection of the ovarian nerve, which innervates uterine blood vessels, counteracted the NAI-induced reduction in uterine blood flow. We suggest that the rapid rise pattern of arterial blood nicotine concentration stimulates and then desensitizes autonomic nAChRs leading to disruptions of cardiac function as well as systemic and uterine hemodynamics that reduces uteroplacental blood flow, a mechanism underlying maternal smoking-associated pregnancy complications and developmental disorders. These findings challenge the safety of pure nicotine inhalation, i.e., E-cigarettes.
Collapse
|
26
|
Phillips B, Titz B, Kogel U, Sharma D, Leroy P, Xiang Y, Vuillaume G, Lebrun S, Sciuscio D, Ho J, Nury C, Guedj E, Elamin A, Esposito M, Krishnan S, Schlage WK, Veljkovic E, Ivanov NV, Martin F, Peitsch MC, Hoeng J, Vanscheeuwijck P. Toxicity of the main electronic cigarette components, propylene glycol, glycerin, and nicotine, in Sprague-Dawley rats in a 90-day OECD inhalation study complemented by molecular endpoints. Food Chem Toxicol 2017; 109:315-332. [PMID: 28882640 DOI: 10.1016/j.fct.2017.09.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 08/23/2017] [Accepted: 09/01/2017] [Indexed: 10/18/2022]
Abstract
While the toxicity of the main constituents of electronic cigarette (ECIG) liquids, nicotine, propylene glycol (PG), and vegetable glycerin (VG), has been assessed individually in separate studies, limited data on the inhalation toxicity of them is available when in mixtures. In this 90-day subchronic inhalation study, Sprague-Dawley rats were nose-only exposed to filtered air, nebulized vehicle (saline), or three concentrations of PG/VG mixtures, with and without nicotine. Standard toxicological endpoints were complemented by molecular analyses using transcriptomics, proteomics, and lipidomics. Compared with vehicle exposure, the PG/VG aerosols showed only very limited biological effects with no signs of toxicity. Addition of nicotine to the PG/VG aerosols resulted in effects in line with nicotine effects observed in previous studies, including up-regulation of xenobiotic enzymes (Cyp1a1/Fmo3) in the lung and metabolic effects, such as reduced serum lipid concentrations and expression changes of hepatic metabolic enzymes. No toxicologically relevant effects of PG/VG aerosols (up to 1.520 mg PG/L + 1.890 mg VG/L) were observed, and no adverse effects for PG/VG/nicotine were observed up to 438/544/6.6 mg/kg/day. This study demonstrates how complementary systems toxicology analyses can reveal, even in the absence of observable adverse effects, subtoxic and adaptive responses to pharmacologically active compounds such as nicotine.
Collapse
Affiliation(s)
- Blaine Phillips
- Philip Morris International Research Laboratories Pte. Ltd. (part of Philip Morris International Group of Companies), 50 Science Park Road, Singapore 117406, Singapore
| | - Bjoern Titz
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Ulrike Kogel
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Danilal Sharma
- Philip Morris International Research Laboratories Pte. Ltd. (part of Philip Morris International Group of Companies), 50 Science Park Road, Singapore 117406, Singapore
| | - Patrice Leroy
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Yang Xiang
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Grégory Vuillaume
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Stefan Lebrun
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Davide Sciuscio
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Jenny Ho
- Philip Morris International Research Laboratories Pte. Ltd. (part of Philip Morris International Group of Companies), 50 Science Park Road, Singapore 117406, Singapore
| | - Catherine Nury
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Emmanuel Guedj
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Ashraf Elamin
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Marco Esposito
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Subash Krishnan
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Walter K Schlage
- Biology Consultant, Max-Baermann-Str. 21, 51429 Bergisch Gladbach, Germany
| | - Emilija Veljkovic
- Philip Morris International Research Laboratories Pte. Ltd. (part of Philip Morris International Group of Companies), 50 Science Park Road, Singapore 117406, Singapore
| | - Nikolai V Ivanov
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Florian Martin
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Manuel C Peitsch
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Julia Hoeng
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland
| | - Patrick Vanscheeuwijck
- Philip Morris International Research and Development (part of Philip Morris International Group of Companies), Philip Morris Products S.A., Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
| |
Collapse
|
27
|
Phillips B, Esposito M, Verbeeck J, Boué S, Iskandar A, Vuillaume G, Leroy P, Krishnan S, Kogel U, Utan A, Schlage WK, Bera M, Veljkovic E, Hoeng J, Peitsch MC, Vanscheeuwijck P. Toxicity of aerosols of nicotine and pyruvic acid (separate and combined) in Sprague-Dawley rats in a 28-day OECD 412 inhalation study and assessment of systems toxicology. Inhal Toxicol 2015; 27:405-31. [PMID: 26295358 DOI: 10.3109/08958378.2015.1046000] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Toxicity of nebulized nicotine (Nic) and nicotine/pyruvic acid mixtures (Nic/Pyr) was characterized in a 28-day Organization for Economic Co-operation and Development 412 inhalation study with additional transcriptomic and lipidomic analyses. Sprague-Dawley rats were nose-only exposed, 6 h/day, 5 days/week to filtered air, saline, nicotine (50 µg/l), sodium pyruvate (NaPyr, 33.9 µg/l) or equimolar Nic/Pyr mixtures (18, 25 and 50 µg nicotine/l). Saline and NaPyr caused no health effects, but rats exposed to nicotine-containing aerosols had decreased body weight gains and concentration-dependent increases in liver weight. Blood neutrophil counts were increased and lymphocyte counts decreased in rats exposed to nicotine; activities of alkaline phosphatase and alanine aminotransferase were increased, and levels of cholesterol and glucose decreased. The only histopathologic finding in non-respiratory tract organs was increased liver vacuolation and glycogen content. Respiratory tract findings upon nicotine exposure (but also some phosphate-buffered saline aerosol effects) were observed only in the larynx and were limited to adaptive changes. Gene expression changes in the lung and liver were very weak. Nic and Nic/Pyr caused few significant changes (including Cyp1a1 gene upregulation). Changes were predominantly related to energy metabolism and fatty acid metabolism but did not indicate an obvious toxicity-related response. Nicotine exposure lowered plasma lipids, including cholesteryl ester (CE) and free cholesterol and, in the liver, phospholipids and sphingolipids. Nic, NaPyr and Nic/Pyr decreased hepatic triacylglycerol and CE. In the lung, Nic and Nic/Pyr increased CE levels. These data suggest that only minor biologic effects related to inhalation of Nic or Nic/Pyr aerosols were observed in this 28-day study.
Collapse
Affiliation(s)
- Blaine Phillips
- a Philip Morris International Research Laboratories Pte Ltd , Science Park II , Singapore and
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Nicotine-Cadmium Interaction Alters Exploratory Motor Function and Increased Anxiety in Adult Male Mice. JOURNAL OF NEURODEGENERATIVE DISEASES 2014; 2014:359436. [PMID: 26317007 PMCID: PMC4437340 DOI: 10.1155/2014/359436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 08/27/2014] [Indexed: 12/05/2022]
Abstract
In this study we evaluated the time dependence in cadmium-nicotine interaction and its effect on motor function, anxiety linked behavioural changes, serum electrolytes, and weight after acute and chronic treatment in adult male mice. Animals were separated randomly into four groups of n = 6 animals each. Treatment was done with nicotine, cadmium, or nicotine-cadmium for 21 days. A fourth group received normal saline for the same duration (control). Average weight was determined at 7-day interval for the acute (D1-D7) and chronic (D7-D21) treatment phases. Similarly, the behavioural tests for exploratory motor function (open field test) and anxiety were evaluated. Serum electrolytes were measured after the chronic phase. Nicotine, cadmium, and nicotine-cadmium treatments caused no significant change in body weight after the acute phase while cadmium-nicotine and cadmium caused a decline in weight after the chronic phase. This suggests the role of cadmium in the weight loss observed in tobacco smoke users. Both nicotine and cadmium raised serum Ca2+ concentration and had no significant effect on K+ ion when compared with the control. In addition, nicotine-cadmium treatment increased bioaccumulation of Cd2+ in the serum which corresponded to a decrease in body weight, motor function, and an increase in anxiety.
Collapse
|