Preclinical evidence for combining the 5-HT2C receptor agonist lorcaserin and varenicline as a treatment for nicotine dependence.

Varenicline, a nicotinic acetylcholine receptor partial agonist, is used to treat nicotine dependence. Lorcaserin, a 5-HT2C receptor agonist has been approved in some countries to treat obesity. Based on preclinical and preliminary clinical evidence, lorcaserin may have potential to treat nicotine dependence. These experiments examined in rats the effects of combining varenicline (0.5 or 1 mg/kg) and lorcaserin (0.3, 0.6 and 1 mg/kg) on nicotine self-administration, reinstatement of nicotine seeking, responding for food and impulsive action. Both drugs alone reduced nicotine self-administration. Combining varenicline and 0.6 mg/kg lorcaserin reduced responding to a greater extent than either drug alone. In a relapse model, extinguished nicotine seeking was reinstated by a priming injection of nicotine and nicotine-associated cues. Reinstatement was reduced by varenicline (1 mg/kg) and by lorcaserin (0.3 mg/kg). Combining lorcaserin (0.3 mg/kg) with varenicline (0.5 or 1 mg/kg) reduced reinstatement to a greater degree than either drug alone. Both drugs had minimal effects on responding for food, alone or in combination. In the five-choice serial reaction time test, varenicline (0.5 or 1 mg/kg) increased impulsivity, measured as increased premature responding. This effect was reduced by lorcaserin (0.3 mg/kg). Plasma levels of varenicline or lorcaserin were not altered by co-administration of the other drug. Varenicline and lorcaserin have additive effects on nicotine self-administration, and on nicotine seeking. Lorcaserin prevents impulsivity induced by varenicline. This pattern of effects suggests that co-administration of varenicline and lorcaserin has potential as a treatment for nicotine dependence that may exceed the value of either drug alone.

Permeability Barriers for Nicotine and Mannitol in Porcine Buccal Mucosa Studied by High-Resolution MALDI Mass Spectrometry Imaging.

Improved nicotine permeability across buccal mucosa may enable more effective oromucosal nicotine replacement therapy products. It is essential to know the location and composition of the main barrier for drug diffusion to enhance the drug permeability. Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) is a rapidly evolving technique that can be used to image the spatial distribution of drugs and drug metabolites in tissue cryo-sections, without prior labeling of the drug. In this study, the distribution of nicotine and mannitol in porcine buccal mucosa was imaged with 10 µm spatial resolution after apical as well as submucosal application of the drugs in order to localize the main permeability barrier(s). This was supported by ex vivo permeability studies across separated porcine buccal epithelium and submucosa. Lastly, the metabolism of nicotine in porcine buccal mucosa was evaluated by imaging of the main metabolite, cotinine. The results showed that the main permeability barrier to both nicotine and mannitol was located in the outer fourth of the epithelium. Further, it was shown that cotinine was sparsely distributed in excised porcine buccal mucosa, indicating that nicotine metabolism in excised porcine buccal mucosa was negligible. MALDI MSI was shown to be a useful method for imaging spatial distribution of drugs in buccal mucosa.

Nicotine Metabolism-informed Care for Smoking Cessation: A Pilot Precision RCT.

Introduction: Varenicline doubles cessation over nicotine replacement therapy (NRT) patch for "normal," but not "slow," nicotine metabolizers, as assessed by the nicotine metabolite ratio (NMR). Metabolism-informed care (MIC) could improve outcomes by matching normal metabolizers with non-nicotine medication (e.g., varenicline) and slow metabolizers with NRT patch. Methods: We conducted a feasibility randomized controlled trial of MIC versus guideline based care (GBC) among 81 outpatient adult daily smokers with medical comorbidity. Participants reported perceptions of MIC, underwent blood draw for NMR, and received expert cessation counseling. For MIC participants, medication selection was informed by NMR result (normal (≥0.31) vs. slow (< 0.31)). The primary outcome was MIC feasibility, reflected by attitudes toward MIC and by match rates between NMR and medication. Secondary endpoints (cessation confidence, medication use, smoking status) were assessed over 6 months to inform future studies. Results: Participants were median age 53 years, 46% female, 28% black, and ~90% endorsed MIC. Despite high varenicline prescription rates (~60%) in both arms, NMR-medication matching was higher in MIC (84%) versus GBC (58%) participants (p=0.02); unadjusted odds ratio (OR) 3.67, 95% confidence interval [1.33, 11.00; p-value=0.02]. Secondary endpoints were similar at 1, 3, and 6 months. Conclusions: MIC, an NMR-based precision approach to smoking cessation, was acceptable to 90% of smokers and improved NMR-medication match rates more than 3-fold compared to GBC, even with generally high use of varenicline. These data support the feasibility of MIC, which could maximize efficacy of smoking cessation medication while minimizing side effects and cost. Implications: Among treatment-seeking daily smokers with medical comorbidity, most viewed metabolism-informed care (MIC), guided by the nicotine metabolism ratio (NMR), favorably, and were willing to accept MIC-guided medication. Compared to GBC participants (58%), more MIC participants (84%) were prescribed NMR-matched medication (i.e., normal metabolizers received varenicline; slow metabolizers received NRT patch). MIC increased the odds of optimized matching between NMR and medication more than 3-fold over GBC. Because the number needed to treat (NNT) to help one normal metabolizer quit smoking is only 4.9 for varenicline versus 26 for patch, broad implementation of MIC will improve drug efficacy in normal metabolizers as well as minimize side effects in slow metabolizers.

Online biological sample preparation with restricted access hybrid carbon nanotubes for determination of anti-smoking drugs.

Untreated samples were injected directly into a column switching system, an online SPE technique, using an extraction column packed with restricted access hybrid carbon nanotubes (RAHCNTs), a novel type of restricted access material, in an ultra-high performance liquid chromatography, coupled to a mass spectrometer (UHPLC-MS/MS). The synthesis of used restricted access material was relatively simple, quick, and reproducible, and had a high material yield. Compared to its predecessor, which is covered with bovine serum albumin (Restricted Access Carbon Nanotubes-RACNTs), RAHCNTs have improved performance when used for the analysis of organic compounds. These molecules have a greater adsorption capacity due to the insertion of hydrophilic monomers (tetraethyl orthosilicate (TEOS), 3-(trimethoxysilyl)propyl methacrylate (MPS), glycerol dimethacrylate (GDMA), and hydroxyethyl methacrylate (HEMA)) in the external layer. In addition, the formation of the hybrid material provides greater chemical and thermal stability, supporting wide pH and temperature ranges, and high concentrations of acidic and basic solutions. It also supports high proportions of organic solvents in the medium. Another significant advantage of the material is its longer lifetime, as it can be reused for approximately 500 analytical cycles without any loss of efficiency, versus 300 for RACNTs. In the method developed to determine anti-smoking drugs (varenicline and bupropion) simultaneously, as well as nicotine and some of their metabolites in human blood serum, the RAHCNTs were capable of retaining the analytes efficiently, whereas the macromolecules were excluded (almost 100%). The method was linear for all the determined analytes (coefficients of determination higher than 0.99), with limits of detection and quantification ranging from 0.6 to 2.5 µg L-1 and from 1.0 to 5.0 µg L-1, respectively. High extraction recovery values were obtained (higher than 88%), as well as inter and intra-assay accuracy and precision results that are in accordance with values recommended by the FDA. The method is promising for therapeutic monitoring and new personalized strategies for patients under antismoking treatment, using a small sample volume (100 µL). In addition, RAHCNTs are capable of simultaneously extracting analytes with very different physical-chemical characteristics.

Does the nicotine metabolite ratio moderate smoking cessation treatment outcomes in real-world settings? A prospective study.

BACKGROUND AND AIMS: In smoking treatment trials comparing varenicline with transdermal nicotine replacement therapy (NRT), stratified by nicotine metabolite (3-hydroxycotinine/cotinine) ratio (NMR), the relative benefit of varenicline is greater among normal rather than slow metabolizers. This study tested if the relative effectiveness of varenicline and NRT is associated with NMR status in a natural treatment setting. A secondary aim was to test if this relationship is moderated by behavioural support. DESIGN: Prospective observational multi-centre study with 4-week and 52-week follow-up. SETTING: Nine English Stop Smoking Services (SSS). PARTICIPANTS: Data came from 1556 smokers (aged ≥ 16 years) attending SSS between March 2012 and March 2013. INTERVENTIONS: Participants received pharmacotherapy together with behavioural support. MEASUREMENTS: The primary outcome was carbon monoxide-verified continuous abstinence at both follow-up times. Main explanatory variables were (1) NMR status [slow (NMR < 0.31, n = 451) versus normal (NMR ≥ 0.31, n = 1105) metabolizers]; (2) pharmacotherapy (varenicline versus NRT) and (3) behavioural support (individual versus group-based treatment). Analyses adjusted for baseline socio-demographic, SSS, mental/physical health and smoking characteristics. FINDINGS: Of participants, 44.2% [95% confidence interval (CI) = 41.7-46.6%] and 8.0% (95% CI = 6.8-9.5%) were continuously abstinent at 4 and 52 weeks. Varenicline was more effective than NRT at 4 weeks (P < 0.001) but only marginally so at 52 weeks (P = 0.061). There was no or inclusive evidence that NMR status moderated relative efficacy of varenicline and NRT at 4- [P = 0.60, Bayes factor (BF) = 0.25] or 52-week follow-ups (P = 0.74, BF = 0.73). However, this relationship was moderated by behavioural support (p = 0.012): the relative benefit of varenicline over NRT at 52-week follow-up was greater in slow, not normal, metabolizers receiving group rather than individual support (P = 0.012). CONCLUSIONS: In a real-world setting, the nicotine metabolite ratio status of treatment-seeking smokers does not appear to contribute substantially to the differential effectiveness of varenicline and nicotine replacement therapy in Stop Smoking Services, when both pharmacotherapy and behavioural support are self-selected.

Tobacco Smoking: Risk to Develop Addiction, Chronic Obstructive Pulmonary Disease, and Lung Cancer.

BACKGROUND: The morbidity and mortality associated with tobacco smoking is well established. Nicotine is the addictive component of tobacco. Nicotine, through the non-neuronal α7nicotinic receptor, induces cell proliferation, neo-angiogenesis, epithelial to mesenchymal transition, and inhibits drug-induced apoptosis. OBJECTIVE: To understand the genetic, molecular and cellular biology of addiction, chronic obstructive pulmonary disease and lung cancer. METHODS: The search for papers to be included in the review was performed during the months of July- September 2018 in the following databases: PubMed (http://www.ncbi.nlm.nih.gov), Scopus (http://www.scopus.com), EMBASE (http://www.elsevier.com/online-tools/embase), and ISI Web of Knowledge (http://apps.webofknowledge.com/). The following searching terms: "nicotine", "nicotinic receptor", and "addiction" or "COPD" or "lung cancer" were used. Patents were retrieved in clinicaltrials.gov (https://clinicaltrials.gov/). All papers written in English were evaluated. The reference list of retrieved articles was also reviewed to identify other eligible studies that were not indexed by the above-mentioned databases. New experimental data on the ability of nicotine to promote transformation of human bronchial epithelial cells, exposed for one hour to Benzo[a]pyrene-7,8-diol-9-10-epoxide, are reported. RESULTS: Nicotinic receptors variants and nicotinic receptors upregulation are involved in addiction, chronic obstructive pulmonary disease and/or lung cancer. Nicotine through α7nicotinic receptor upregulation induces complete bronchial epithelial cells transformation. CONCLUSION: Genetic studies highlight the involvement of nicotinic receptors variants in addiction, chronic obstructive pulmonary disease and/or lung cancer. A future important step will be to translate these genetic findings to clinical practice. Interventions able to help smoking cessation in nicotine dependence subjects, under patent, are reported.