‘To prove this is the industry's best hope’: big tobacco's support of research on the genetics of nicotine addiction

Background New molecular techniques focus a genetic lens upon nicotine addiction. Given the medical and economic costs associated with smoking, innovative approaches to smoking cessation and prevention must be pursued; but can sound research be manipulated by the tobacco industry? Methodology The chronological narrative of this paper was created using iterative reviews of primary sources (the Legacy Tobacco Documents), supplemented with secondary literature to provide a broader context. The empirical data inform an ethics and policy analysis of tobacco industry‐funded research. Findings The search for a genetic basis for smoking is consistent with industry's decades‐long plan to deflect responsibility away from the tobacco companies and onto individuals' genetic constitutions. Internal documents reveal long‐standing support for genetic research as a strategy to relieve the tobacco industry of its legal responsibility for tobacco‐related disease. Conclusions Industry may turn the findings of genetics to its own ends, changing strategy from creating a ‘safe’ cigarette to defining a ‘safe’ smoker.     

Tobacco consumption and its association with illicit drug use among men in Bangladesh

AIMS: This study examined the association of tobacco consumption (smoking and chewing) with illicit drug use among Bangladesh males. DESIGN: Cross-sectional survey data from the Bangladesh Demographic and Health Survey 2004 were used. SETTING: Bangladesh. PARTICIPANTS: A total of 4297 males aged 15-54 years. MEASUREMENTS: Age, education, religion, marital status, place of residence; tobacco consumption such as cigarette and bidi smoking, chewing sada, pata, tobacco leaves, gul, betel quid with zarda; taking illicit drugs such as ganja, charas, heroin, pethedine, phensidyl; having sexually transmitted diseases (STDs). FINDINGS: Overall prevalence of tobacco consumption was 59%. Bidi smoking (29.6%), cigarette smoking (27.8%) and chewing betel quid with tobacco/zarda (17.5%) were predominant. Overall prevalence of illicit drug use was 4%. Ganja was the main drug (3%), followed by phensidyl (0.8%), heroin (0.3%) and charas (0.3%). Age, education, place of residence, marital status, having STDs, premarital and extra-marital sex were associated significantly with tobacco smoking. Almost all variables were also associated significantly with illicit drug use. Smoking cigarettes and bidi and eating tobacco leaves/shada pata/gul showed significantly positive associations with illicit drug use when adjusted for other variables. CONCLUSIONS: Tobacco consumption is common and associated positively with the illicit drug use among males in Bangladesh.     

The impact of strategic funding by the tobacco industry of medical expert witnesses appearing for the defence in the Aho Finnish product liability case

AIMS: To identify and evaluate tobacco industry strategies to recruit medical expert witnesses. METHODS: A systematic search was made of internal tobacco industry documents available on the Internet and at British American Tobacco Guildford Depository. Litigation by a plaintiff with laryngeal cancer against the tobacco industry in Finland was used as a case study of tobacco industry strategies to manipulate science and its use and deployment in defending a product liability claim. RESULTS: Thirty-three of 45 medical expert witnesses for the defence received research funding before or after testifying. One strategy was to employ those scientists as witnesses with whom the industry had worked since the 1960s. The older witnesses testified to the existence of a controversy which they had, in fact, helped to create. Those appearing in Helsinki District court apparently downplayed the importance of their involvement with the industry. Another strategy was the use of research funding to establish contacts with new potential witnesses, to strengthen existing contacts or to pay back helpful experts. CONCLUSIONS: The tobacco industry funded the majority of expert witnesses appearing for it, beyond simple recompense for the time involved. This may have unconsciously influenced the testimony given by the witnesses. This funding should be considered in court, but links between experts and the industry were often downplayed or, in some cases, the financial ties were being forged at the time and were not revealed. It would be helpful to establish norms to guide courts to understand the influences exerted by the tobacco industry in the preparation of cases requiring expert evidence.     

Snus and risk of gastroesophageal reflux. A population-based case-control study: the HUNT study

Objective: Tobacco smoking is a risk factor for gastroesophageal reflux, but whether other tobacco products increase the risk is unclear. The aim of this study was to investigate if snus increases the risk of gastroesophageal reflux symptoms (GERS).

Material and methods: The study was based on the third Nord-Trøndelag health study (HUNT3), a population-based study of all adult residents in Nord-Trøndelag County, Norway, performed in 2006–2009. The association between self-reported severe heartburn/regurgitation and snus use was assessed by logistic regression.

Results: Compared to never snus users, daily snus users had a reduced risk of GERS (OR 0.77, 95% confidence interval [CI] 0.64–0.93), while previous snus users and those using?<2 boxes of snus/month had an increased risk (OR 1.20, 95% CI 1.00–1.46 and OR 1.41, 95% CI 1.02–1.96, respectively). There was no association between age when starting using snus and GERS. Snus users who started using snus to quit or cut down on cigarette smoking, who started using both snus and cigarettes or cigarettes alone had an increased risk of GERS. Snus users?<30 years of age had an increased risk of GERS (OR 1.49, 95% CI 1.02–2.16), while those aged between 50–60 and 60–70 years had a reduced risk (OR 0.67, 95% CI 0.49–0.93 and OR 0.51, 95% CI 0.28–0.94, respectively).

Conclusions: Daily snus users had a reduced risk of GERS. However, previous snus users and subgroups of snus users had an increased risk of GERS indicating reverse causality, such that snus use could increase the risk of GERS.     

The case for the plain packaging of tobacco products

AIMS: The Framework Convention on Tobacco Control (FCTC) requires nations that have ratified the convention to ban all tobacco advertising and promotion. In the face of these restrictions, tobacco packaging has become the key promotional vehicle for the tobacco industry to interest smokers and potential smokers in tobacco products. This paper reviews available research into the probable impact of mandatory plain packaging and internal tobacco industry statements about the importance of packs as promotional vehicles. It critiques legal objections raised by the industry about plain packaging violating laws and international trade agreements. METHODS: Searches for available evidence were conducted within the internal tobacco industry documents through the online document archives; tobacco industry trade publications; research literature through the Medline and Business Source Premier databases; and grey literature including government documents, research reports and non-governmental organization papers via the Google internet search engine. RESULTS: Plain packaging of all tobacco products would remove a key remaining means for the industry to promote its products to billions of the world's smokers and future smokers. Governments have required large surface areas of tobacco packs to be used exclusively for health warnings without legal impediment or need to compensate tobacco companies. CONCLUSIONS: Requiring plain packaging is consistent with the intention to ban all tobacco promotions. There is no impediment in the FCTC to interpreting tobacco advertising and promotion to include tobacco packs.     

Effects of nicotine deprivation on urges to drink and smoke in alcoholic smokers

Aim This study examined the effect of nicotine deprivation on alcohol and smoking urges in a sample of alcohol‐dependent smokers in early recovery. Design Using a within‐subjects design, participants underwent two cue‐reactivity laboratory sessions in which they rated their urges for alcohol and cigarettes during the following three trials: baseline, neutral cue and mood induction combined with alcohol beverage cue exposure. One session was completed after 34 hours of nicotine deprivation and another in a non‐deprived state. Participants Forty alcohol‐dependent heavy smokers recruited from a substance abuse day treatment program. Measurements Self‐reported urge to drink, urge to smoke and salivation. Findings Results showed that during the non‐deprived session, alcohol cue presentations were associated with significant increases in urges to drink and urges to smoke. Acute nicotine deprivation led to increased smoking urges, but was not associated with increased urges to drink alcohol. Conclusions Findings suggest that the acute effects of smoking cessation are unlikely to increase risk of relapse to alcohol in alcoholic patients who are undergoing treatment.     

INAUGURAL ARTICLE by a Recently Elected Academy Member:Natural history-driven,plant-mediated RNAi-based study reveals CYP6B46’s role in a nicotine-mediated antipredator herbivore defense

Manduca sexta (Ms) larvae are known to efficiently excrete ingested nicotine when feeding on their nicotine-producing native hostplant, Nicotiana attenuata. Here we describe how ingested nicotine is co-opted for larval defense by a unique mechanism. Plant-mediated RNAi was used to silence a midgut-expressed, nicotine-induced cytochrome P450 6B46 (CYP6B46) in larvae consuming transgenic N. attenuata plants producing MsCYP6B46 dsRNA. These and transgenic nicotine-deficient plants were planted into native habitats to study the phenotypes of larvae feeding on these plants and the behavior of their predators. The attack-behavior of a native wolf spider (Camptocosa parallela), a major nocturnal predator, provided the key to understanding MsCYP6B46’s function: spiders clearly preferred CYP6B46-silenced larvae, just as they had preferred larvae fed nicotine-deficient plants. MsCYP6B46 redirects a small amount (0.65%) of ingested nicotine from the midgut into hemolymph, from which nicotine is exhaled through the spiracles as an antispider signal. CYP6B46-silenced larvae were more susceptible to spider-attack because they exhaled less nicotine because of lower hemolymph nicotine concentrations. CYP6B46-silenced larvae were impaired in distributing ingested nicotine from midgut to hemolymph, but not in the clearing of hemolymph nicotine or in the exhalation of nicotine from hemolymph. MsCYP6B46 could be a component of a previously hypothesized pump that converts nicotine to a short-lived, transportable, metabolite. Other predators, big-eyed bugs, and antlion larvae were insensitive to this defense. Thus, chemical defenses, too toxic to sequester, can be repurposed for defensive functions through respiration as a form of defensive halitosis, and predators can assist the functional elucidation of herbivore genes.Plants produce a pharmacopeia of potent chemical defenses that prevent the attack of unadapted herbivores and thwart the growth of adapted ones. Frequently, lepidopteran herbivores co-opt these diet-acquired toxins for their own defensive purposes. The eastern tent caterpillar (Malacosoma americanum) regurgitates hydrogen cyanide and benzaldehyde ingested from their cyanogenic hostplants when attacked by ants (1). The Atala butterfly (Eumaeus atala) acquires a toxic azoxyglycoside from its cycad hosts and becomes unpalatable to bird and ant predators (2). Similarly, rattlebox moths (Utetheisa ornatrix) co-opt pyrrolizidine alkaloids that their larvae sequester while feeding on rattlebox legume hostplants (Crotalaria spp.) to deter predatory spiders (3). Prey frequently advertise their toxic status with warning colorations, odors, and behaviors, and predators readily learn these aposematic signals to avoid consuming toxic prey (4). The molecular mechanisms of how herbivores co-opt plant defenses for their own defense remain largely unexplored.The pyridine alkaloid nicotine is a defense metabolite of several Nicotiana spp. Nicotine is extremely effective against herbivores because of its ability to poison the essential neuromuscular junction common to all animals that use muscles to move: the acetylcholine receptor (5, 6). Nicotiana spp. hostplants respond to the herbivore attack with large increases in nicotine accumulation (7). However, the tobacco hornworm (Manduca sexta, Ms), a specialist lepidopteran herbivore that feeds on nicotine-producing Nicotiana plants, tolerates doses of nicotine that are lethal for unadapted herbivores (8). More endoparasitoid wasps (Cotesia congregata) emerged as adults from parasitized M. sexta larvae fed on low nicotine varieties of cultivated tobacco than from larvae fed on nicotine-rich varieties (9). The generalist predatory argentine ant (Iridomyrmex humilis) also preferred M. sexta larvae reared on artificial diets (AD) without nicotine over those reared on high nicotine diets, and were deterred by topical nicotine treatments (10). These results suggest that M. sexta larvae might be able to use this diet-derived toxin for their own protection. How this happens remains a mystery, as the larvae’s resistance of ingested nicotine does not appear to include sequestration and storage of this toxin.The exact mechanisms responsible for M. sexta’s nicotine resistance remain unclear, but both efficient excretion and metabolism appear to be involved. Some researchers have focused on the polar metabolites of nicotine, such as cotinine and the N-oxides of both nicotine and cotinine, which are commonly found in the urine and blood of human smokers (8, 11, 12); cytochrome P450s (CYPs) are thought to mediate nicotine’s oxidation to these metabolites (8, 11, 13–15), but other researchers have been unable to find the oxides in M. sexta’s excretions and propose that nicotine is rapidly excreted without modification (16–18). Although this theory is widely accepted, most studies have not been able to recover all of the ingested nicotine in the frass and nicotine can be found in the hemolymph of larvae feeding on nicotine-containing diets. Hence, within these physiological limits of M. sexta’s excretory-based tolerance lie opportunities for the defensive use of nicotine. Whether nicotine-resistance and co-option are regulated by a common mechanism remains unknown.Here we examine how M. sexta larvae co-opt diet-ingested nicotine for their own defense. In a previous unbiased microarray study, we found that a midgut-expressed cytochrome P450 (CYP6B46) was strongly down-regulated in larvae that were fed genetically modified hostplants with suppressed nicotine production (19, 20). To evaluate if this CYP6B46 is involved in nicotine resistance and co-option, we used a reverse genetics approach, plant-mediated RNA interference (PMRi) (20, 21), to silence this gene in larvae feeding on nicotine-containing, native coyote tobacco (Nicotiana attenuata) hostplants transformed to harbor the silencing construct. Lepidopteran herbivores appear to lack the RNA-dependent RNA polymerase required to sustain gene silencing by RNAi; however, a continuous supply of double-stranded (ds)RNA administered via the hostplant (or diet) effectively silences genes in these herbivores (21, 22).N. attenuata plants were transformed with an expression vector containing a 300-bp fragment of CYP6B46 in an inverted repeat (ir) orientation. Continuous dsRNA ingestion efficiently silenced CYP6B46 in the midguts of larvae feeding on these plants in a highly target-sequence–specific manner, as the most similar CYP expressed in larval midguts, CYP6B45, was not cosilenced (20). These PMRi plants were planted into the native habitat of both hostplant and larvae, the Great Basin Desert, Utah, which teems with larval predators—such as bugs, mantids, ants, antlions, spiders, and lizards—but lacks the Argentine ants and C. congregata endoparasitoids previously reported to be nicotine-sensitive. One of these predators, a wolf spider [Camptocosa parallela (Lycosidae)], selectively attacked CYP6B46-silenced larvae just as it did larvae feeding on nicotine-free hostplants. The particular predatory behavior of these spiders revealed the function of MsCYP6B46 in externalizing ingested nicotine for defensive use. The combination of natural history studies and the plant- and herbivore-reverse genetic procedures can fruitfully dissect the molecular mechanisms governing the tritrophic interactions.