Impact of more intense smoking parameters and flavor variety on toxicant levels in emissions of a Heated Tobacco Product.

INTRODUCTION: IQOS HEETS are promoted as reduced risk alternatives to cigarettes. Although some studies have investigated the chemical composition of HEETS emissions, little is known on whether toxicant levels in such emissions are affected by different puffing parameters and flavor varieties. This has important implications when assessing actual human exposure, since IQOS users develop a specific and personalized puffing behavior and may use different HEETS variants. METHODS: This study measured the levels of nicotine, Total Particulate Matter (TPM), carbonyl compounds and tobacco-Specific Nitrosamines (TSNAs) in the emissions of nine differently flavored HEETS and two cigarettes (1R6F and Marlboro Red, MR). Emissions from Yellow HEETS, 1R6F and MR were collected using the World Health Organization Intense (WHOI) smoking regime and four more intense smoking regimes. RESULTS: Yellow HEETS aerosol contained lower levels of toxicants compared to 1R6F and MR smoke. More intense smoking regimes increased carbonyls release in cigarette smoke, whereas only higher puff frequency led to lower levels of toxicants in Yellow HEETS aerosol. Some HEETS varieties exhibited higher levels of formaldehyde and TSNAs in their aerosol compared to Yellow HEETS. CONCLUSIONS: Puff frequency was identified as the only smoking parameter that significantly lowered the release of almost all toxicants in Yellow HEETS, whereas a combination of higher puff volume and puff duration led to increased levels of some carbonyls. Differences in toxicants levels between various commercially-available HEETS have important implications when assessing their health impact, as their consumption might induce different toxicant exposure and health effects. IMPLICATIONS: HEETS release about half as much nicotine and substantially lower levels of toxicants compared to cigarettes. Literature data showed that puffing intensity is increased in cigarette smokers switching to HEETS, maybe in reaction to these lower nicotine levels. Our results show a differential impact of increased puff frequency, puff duration and puff volume in the release of toxicants from HEETS. Thus, industry-independent studies on puff topography are critical to make choices for the most relevant puffing regime for HTP regulation. Regulators should consider evaluating the health impact of multiple HEETS varieties, as the tobacco filler composition significantly affects the release of certain toxicants.

Impact of sub-acute acrolein inhalation on the molecular regulation of mitochondrial metabolism in rat lung.

Nowadays, mitochondria are recognized as key players in the pathogenesis of a variety of smoking-associated lung diseases. Acrolein, a component of cigarette smoke, is a known driver of biological mechanisms underlying smoking-induced respiratory toxicity. The impact of sub-acute acrolein inhalation in vivo on key processes controlling mitochondrial homeostasis in cells of the airways however is unknown. In this study, we investigated the activity/abundance of a myriad of molecules critically involved in mitochondrial metabolic pathways and mitochondrial quality control processes (mitochondrial biogenesis and mitophagy) in the lungs of Sprague-Dawley rats that were sub-acutely exposed to filtered air or 3 ppm acrolein by whole-body inhalation (5 h/day, 5 days/week for 4 weeks). Acrolein exposure induced a general inflammatory response in the lung as gene expression analysis revealed an increased expression of Icam1 and Cinc1 (p < 0.1; p < 0.05). Acrolein significantly decreased enzyme activity of hydroxyacyl-Coenzyme A dehydrogenase (p < 0.01), and decreased Pdk4 transcript levels (p < 0.05), suggestive of acrolein-induced changes in metabolic processes. Investigation of constituents of the mitochondrial biogenesis pathways and mitophagy machinery revealed no pronounced alterations. In conclusion, sub-acute inhalation of acrolein did not affect the regulation of mitochondrial metabolism and quality control, which is in contrast to more profound changes after acute exposure in other studies.

Acrolein inhalation acutely affects the regulation of mitochondrial metabolism in rat lung.

Exposure of the airways to cigarette smoke (CS) is the primary risk factor for developing several lung diseases such as Chronic Obstructive Pulmonary Disease (COPD). CS consists of a complex mixture of over 6000 chemicals including the highly reactive α,ß-unsaturated aldehyde acrolein. Acrolein is thought to be responsible for a large proportion of the non-cancer disease risk associated with smoking. Emerging evidence suggest a key role for CS-induced abnormalities in mitochondrial morphology and function in airway epithelial cells in COPD pathogenesis. Although in vitro studies suggest acrolein-induced mitochondrial dysfunction in airway epithelial cells, it is unknown if in vivo inhalation of acrolein affects mitochondrial content or the pathways controlling this. In this study, rats were acutely exposed to acrolein by inhalation (nose-only; 0-4 ppm), 4 h/day for 1 or 2 consecutive days (n = 6/group). Subsequently, the activity and abundance of key constituents of mitochondrial metabolic pathways as well as expression of critical proteins and genes controlling mitochondrial biogenesis and mitophagy were investigated in lung homogenates. A transient decreasing response in protein and transcript abundance of subunits of the electron transport chain complexes was observed following acrolein inhalation. Moreover, acrolein inhalation caused a decreased abundance of key regulators associated with mitochondrial biogenesis, respectively a differential response on day 1 versus day 2. Abundance of components of the mitophagy machinery was in general unaltered in response to acrolein exposure in rat lung. Collectively, this study demonstrates that acrolein inhalation acutely and dose-dependently disrupts the molecular regulation of mitochondrial metabolism in rat lung. Hence, understanding the effect of acrolein on mitochondrial function will provide a scientifically supported reasoning to shortlist aldehydes regulation in tobacco smoke.

Gastrointestinal digestion of dietary advanced glycation endproducts increases their pro-inflammatory potential.

Thermal treatment of food products leads to the formation of dietary advanced glycation endproducts (dAGEs). It was previously shown that dAGEs induce TNF-α secretion in human macrophage-like cells. To what extent gastrointestinal digestion of dAGEs influences these pro-inflammatory effects and what the implications of these pro-inflammatory characteristics further down the human gastrointestinal tract are, are currently unknown. In one of our previous studies, dAGEs were digested using the TNO gastroIntestinal Model and analysed for dAGE quantity after digestion. In the current study both digested and undigested dAGEs were used to expose human macrophage-like cells, which were subsequently analysed for TNF-α secretion. In addition, the obtained digests were fractionated, and human macrophage-like cells were exposed to the different fractions to determine whether specific fractions induce TNF-α secretion. The results show that digested dAGEs have an increased pro-inflammatory effect on human macrophage-like cells compared to undigested dAGEs. This paper therefore shows that the digestion of food-components, and specifically dAGEs, plays an important role in determining their biological activity.

Subchronic inhalation of mixtures of cigarette smoke constituents in Xpa-/-p53+/- knock-out mice: a comparison of intermittent with semi-continuous exposure to acetaldehyde, formaldehyde, and acrolein.

We investigated whether inhaling peak concentrations of aldehydes several times daily is more damaging than semi-continuously inhaling low-dose aldehydes. We exposed Xpa-/-p53+/- knock-out mice either intermittently or semi-continuously to mixed acetaldehyde, formaldehyde, and acrolein. The intermittent regimen entailed exposure to the aldehydes 7 min every 45 min, 12 times/day, 5 days/week, corresponding to concentrations inhaled by smokers. Semi-continuously exposed animals received half the dose of aldehydes in 8h/day, 5 days/week. Some mice in each group were sacrificed after 13 weeks of exposure; the rest breathed clean air until the end of 1 year. Mice injected intratracheally with benzo[a]pyrene formed a positive control group. The nasal cavity, lungs, and any macroscopically abnormal organs of all mice were analysed histopathologically. After 13 weeks of exposure, the subacute, overall, histopathological changes induced by the inhalation differed noticeably between the intermittently and semi-continuously treated Xpa-/-p53+/- knock-out mice. After 13 weeks of mixed aldehyde exposure, atrophy of the olfactory epithelium generally appeared, but disappeared after 1 year (adaptation and/or recovery). Respiratory epithelial metaplasia of the olfactory epithelium occurred at a higher incidence at 1 year. Except for a significantly greater number of tumours observed in knock-out mice compared to wild mice (semi-continuous aldehyde exposure and controls), no differences between the semi-continuous and intermittent exposure groups were observed.

Risk assessment of khat use in the Netherlands: a review based on adverse health effects, prevalence, criminal involvement and public order.

In preparing a decision about the legal status of khat in the Netherlands, the Dutch Minister of Health requested CAM (Coordination point Assessment and Monitoring new drugs) to assess the overall risk of khat in the Netherlands. The present paper is a redraft of a report which formed the scientific basis of the risk evaluation procedure (October 2007). This report reviews the scientific data about khat available in the international literature. In addition, the report contains some information specific for the Netherlands (prevalence, availability of khat and public order aspects). The main psychoactive compounds in khat leaves are cathine and cathinone, which are some 2- to 10-fold less active than amphetamine. Acute health problems are rarely seen, and are usually related with malnutrition, social and financial problems. Khat has a low addictive potential. Chronic toxicity of khat is modest when used in low amounts, whereas at high levels, khat use is associated with adverse effects, like hypertension, heart rhythm disorders, insomnia and loss of appetite. In addition, khat users show a higher prevalence of cancers in the digestive tract. At population level, khat does not lead to specific health risks in the Netherlands, as its use is confined to East-African immigrants. A relationship between khat use and psychiatric disorders has been suggested, but the reports are contradictory, and such studies are presumably heavily confounded by posttraumatic and social stress. In the Netherlands (and other countries), khat use occasionally leads to minor disturbance of civil order in the public domain (loud talking, spitting), but is not related to criminal activities. Following the assessment, CAM estimated the overall risk potential of khat use in the Netherlands as very low. A similar conclusion may be drawn for countries with a comparable prevalence of khat use and khat related public order disturbance.

Significance of ammonium compounds on nicotine exposure to cigarette smokers.

The tobacco industry publicly contends that ammonia compounds are solely used as tobacco additive for purposes of tobacco flavoring, process conditioning and reduction of its subjective harshness and irritation. However, neither objective scientific reports, nor the contents of a large number of internal tobacco company documents support this contention. The present review focuses on the hypothesis that addition of ammonium compounds to tobacco enhances global tobacco use due to smoke alkalization and enhanced free-nicotine nicotine exposure. Obviously, ammonia enhances the alkalinity of tobacco smoke. Consequently, the equilibrium shifts from non-volatile nicotine salts to the volatile free base that is more readily absorbed from the airways. The observed change in the kinetics of nicotine (i.e., shorter t(1/2) and higher c(max)) after ammoniation is, however, predominantly due to the higher concentration of nicotine in the smoke, rather than to an increase in the absorption rate of free-base nicotine in the respiratory tract. Although several findings support the hypothesis, additional studies are required and suggested to provide a proper, objective and independent scientific judgment about the effect of tobacco ammoniation on nicotine bioavailability. Scientific and public awareness of the effects of tobacco-specific ammonia compounds may stimulate global control, legislation and restriction of their use in cigarette manufacture.

Skin and liver diseases induced in flounder (Platichthys flesus) after long-term exposure to contaminated sediments in large-scale mesocosms.

Disease development in flounder (Platichthys flesus) was studied over a period of 3 years in three large mesocosms (40 m x 40 m x 3 m). Two of the mesocosms contained clean sand and the third, sharing a common water circulation with one of the clean-sand mesocosms, was stocked with contaminated dredged spoil. In this way, one of the clean-sand mesocosms was indirectly polluted via the water phase, and analysis of contaminant concentrations in sediments and flounder tissues showed that it had a status intermediate between the other two. Random samples of the flounder populations from the indirectly polluted and reference mesocosms were examined every 2 months for epidermal diseases (lymphocystis, skin ulcers, fin rot) and then released. In addition, every 6 months, random samples of fish from all three mesocosms were sacrificed for histological and chemical investigation. With regard to the development of epidermal disease, the results showed little difference between the reference mesocosm and the indirectly polluted mesocosm, with the exception that lymphocystis was significantly elevated in the indirectly polluted mesocosm. Although pollution may be a risk factor in the etiology of this disease, such a relationship would probably be obscured under field conditions due to variation arising from other factors. Histopathological analysis of the livers revealed in total four cases of hepatocellular adenoma (1.5% of sampled population) in fish from the polluted mesocosms, the first occurring after 2.5 years of exposure in fish from the indirectly polluted mesocosm. Furthermore, several other liver lesions, including foci of cellular alteration and hydropic vacuolated lesions, developed during the course of the experiment before tumor formation was apparent. Prevalences of these conditions were very much lower in the reference mesocosm than in the two polluted mesocosms. Densities of melanomacrophage centers in the liver showed a similar trend. The findings clearly indicate that long-term exposure to chemically contaminated dredged spoil can induce liver neoplasia and other liver lesions in flounder at contaminant levels comparable to those found in the natural environment.

Nitric oxide and biopterin in depression and stress.

Depression has been hypothesized to be related to the reduced biosynthesis of neurotransmitters such as serotonin, noradrenalin and dopamine. Much past research has also been devoted to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in depression. The present article reviews the evidence linking tetrahydrobiopterin, a co-factor in the biosynthesis of neurotransmitters, and nitric oxide, an apparent neuroendocrine modulator of the HPA axis, to the immune system and to neuronal control within affective disorder and stress. On the basis of this review, it is suggested that future psychoneuroimmunological research should more fully explore the possible role of tetrahydrobiopterin and nitric oxide in depressive disorders.

Embryotoxicity of carbamazepine in rat postimplantation embryo culture after in vitro exposure via three different routes.

Postimplantation rat embryo culture is used widely for studies of embryotoxic effects on the isolated embryo after in vitro exposure to xenobiotic compounds. In this study, the relevance of three routes of exposure of the embryo in vitro was evaluated using the embryotoxic anticonvulsant carbamazepine. Embryotoxic effects were assessed, and analyses in conceptus tissues were done to reveal uptake and metabolism of the compound. Exposure via the culture medium resulted in neural tube defects and general retardation of growth and development. After injections into the amniotic or exocoelomic space, local membrane adhesions were found. Intra-amniotic exposure caused adhesions of the amniotic membrane with the embryonic neural plate, resulting in trapping of the membrane in the closing neural tube, as well as in open neural tube defects occurring in various areas of the neural tube. Only after exposure via the culture medium were amounts of carbamazepine detectable in the embryonic tissue, correlating with the systemic effects found. It is concluded that uptake from the culture medium via the yolk sac circulation is the relevant exposure route to be used for embryotoxicity effect assessment.

Influence of contaminated particles on the bioaccumulation of hydrophobic organic micropollutants in fish.

The influence of contaminated particles on the bioconcentration of hydrophobic chemicals by fish is dependent on the hydrophobicity of the chemicals. This has been shown for polychlorinated benzenes and biphenyls (ranging over three orders of magnitude in octan-1-ol/water partition coefficient) which are sorbed on very low organic carbon content particles. For chemicals with low to moderate hydrophobicity, the amount of the chemical which is sorbed, relative to the amount which is dissolved, determines the influence that contaminated particles have on the uptake of the chemicals by fish. In this present experiment, for lower chlorinated benzenes and biphenyls, the amount dissolved in water are high compared with the amounts which are present in the sorbed state, and the influence of contaminated particles on their uptake by fish is negligible. For more hydrophobic chemicals, which have lower aqueous solubilities, such as penta and hexachlorobenzene, and tri and tetrachlorobiphenyls, contaminated particles can have a much greater influence on the uptake by fish. If the number of contaminated particles is sufficiently high, the low aqueous solubilities, in combination with relatively high rates of desorption or dissolution, enable the particles to act as a source of the hydrophobic chemicals. For extremely hydrophobic chemicals, the rates of dissolution or desorption determine the rates of uptake of the chemical by the fish. Hence, during relatively short periods of exposure, there is no influence of contaminated particles on the bioaccumulation.

Influence of survival time on the lethal body burden of 2,3,4,5-tetrachloroaniline in the guppy, Poecilia reticulata.

The lethal body burden (LBB) of 2,3,4,5-tetrachloroaniline in guppy (Poecilia reticulata), exposed for up to 14 days, has been determined at different aqueous concentrations of the test compound. It was found that the LBB is not constant during these 14 days, declining within the first 48 h to an approximately constant value. It is concluded that LBBs of organic compounds may not always be constant and may depend on survival time.

Use of lethal body burdens to indicate species differences in susceptibility to narcotic toxicants.

Lethal body burdens (LBB) for 1,2- and 1,4-dihalogenated benzenes (F, Cl or Br) are determined in rainbow trout of two age-classes. LBBs range from 0.3 to 2.4 mmol/kg. There are no significant differences between the two tested age-classes of rainbow trout. The rainbow trout data are compared to LBBs for 1,2- and 1,4-difluorobenzene in fathead minnow which range from 2.7 to 3.0 mmol/kg, and to LBBs of dichloro- and dibromobenzenes in guppy and fathead minnow [Sijm et al. 1993] which range from 2.7 to 8.0 mmol/kg. Rainbow trout are more susceptible to dihalogenated benzenes than fathead minnow. The LBB can be used as an instrument to examine the intrinsic toxicity of a chemical to a species, and to indicate the susceptibility of a species. Possible reasons for differences in susceptibility among species are discussed.

Exhaled nitric oxide: a novel biomarker of adverse respiratory health effects in epidemiological studies.

The sampling of exhaled breath is a noninvasive procedure that can be performed easily in adults, children, and patients with respiratory disease. Several studies have demonstrated increased exhaled nitric oxide in patients with pulmonary disease, including asthma. In addition, exhaled nitric oxide may be an elegant tool for monitoring of environmental health effects of air pollution and the prevalence of atopy in epidemiological surveys. Recent literature about exhaled nitric oxide is presented in this article. Technical, physiological, and behavioral confounding factors of exhaled nitric oxide measurement are outlined.

Air pollution is associated with increased level of exhaled nitric oxide in nonsmoking healthy subjects.

The authors sought to determine which air pollutant is responsible for the increase in exhaled nitric oxide observed in healthy subjects. Exhaled nitric oxide was measured in 16 nonsmoking healthy subjects on 14 workdays, during which there were varying air-pollution levels. Contamination of samples by ambient nitric oxide was excluded. The baseline value of exhaled nitric oxide, determined at times when outdoor air pollution was low, ranged from 7 to 43 ppb (mean = 28+/-5 ppb). The daily value of exhaled nitric oxide (range = 5-60 ppb) was associated positively with ambient carbon monoxide (r = .85) and nitric oxide (r = .81). Exposure during the morning hours to high levels of outdoor pollution was associated with increased exhaled nitric oxide (i.e., 50% above baseline), which persisted for up to 5 h (i.e., 32% above baseline). These results indicated that exhaled nitric oxide levels represent a useful biomonitor of individual exposure to air pollutants.

Traffic-related air pollution affects peak expiratory flow, exhaled nitric oxide, and inflammatory nasal markers.

The authors used a longitudinal observational design, with repeated measures, to study the association between traffic-related air pollutants (i.e., nitric oxide, nitrogen dioxide, carbon monoxide, and Black Smoke) and respiratory symptoms. Subjects (N = 82) attended an elementary school in either Utrecht (i.e., urban children) or Bilthoven (i.e., suburban children). These two geographic areas differed with respect to levels of Black Smoke (means = 53 microg/m3 and 18 microg/m3, respectively). Levels of nitric oxide, nitrogen dioxide, carbon monoxide, and Black Smoke were consistently higher in Utrecht than in Bilthoven (mean daily ratios were 8, 1.5, 1.8, and 2.7, respectively). The authors compared mean levels of short-term effects of the aforementioned air pollutants on suburban and urban children. Urban children had higher mean levels (p = .05) of interleukin-8 (32%), urea (39%), uric acid (26%), albumin (15%), and nitric oxide metabolites (21%) in nasal lavage than did suburban children. Peak expiratory flow, exhaled nitric oxide levels, and nasal markers were associated with levels of particulate matter with diameters less than or equal to 10 microm, Black Smoke, nitrogen dioxide, and nitric oxide. With respect to per-unit increases in air pollution, urban children had more increased peak expiratory flow, higher levels of exhaled nitric oxide, and more increased release of uric acid, urea, and nitric oxide metabolites than suburban children. In summary, urban children had increased levels of inflammatory nasal markers, and their responses were more pronounced than were the suburban children's responses to the same increments of air pollution.

Sorption kinetics of chlorinated hydrophobie organic chemicals : Part I: The Use Of First-Order Kinetic Multi-Compartment Models.

This is the first of a two-part series describing the Sorption kinetics of hydrophobic organic chemicals. This paper discusses the use of first-order kinetic compartment models in environmental studies, of subjects such as bioaccumulation and sorption. A comprehensive mathematical description and model calculations are presented. Differences between these models and the pharmacokinetic compartment models will be indicated, emphasis being given to the use of the former in sorption studies.

Sorption kinetics of chlorinated hydrophobic organic chemicals : Part II: Desorption experiments.

This is the second of a two-part series describing the sorption kinetics of hydrophobic organic chemicals. Part I "The Use of First-Order Kinetic Multi-Compartment Models" is published in issue 1 of this journal, pp. 21-28. Sorption kinetics of chlorinated benzenes from a natural lake sediment have been investigated in gas-purge desorption experiments. Biphasic desorption curves, with an initial "fast" part and a subsequent "slow" part, were found for all tested chlorobenzenes. From these results first-order sorption uptake and desorption rate constants were calculated with a two-sediment compartment model, which is presented in the first paper.In three sets of experiments the sorption uptake period and sediment/water ratio were varied. Rate constants are not influenced by these experimental conditions, which supports the partitioning concept for the sorption of hydrophobic organic chemicals in sediments.

Gene expression pattern in spontaneously hypertensive rats exposed to urban particulate matter (EHC-93).

Epidemiological studies show associations of short-term exposure to particulate matter with morbidity and mortality. Although many studies investigate the health effects of ambient particulate matter, the associated mechanisms, and the causality, they often focus on classical parameters. The objective of the present study was to gain insight into the roles of a wide range of genes in this process. Particular attention has been paid to immediate oxidative stress in the lung. We isolated total lung RNA from spontaneously hypertensive male rats 2-40 h after exposure to reference EHC-93 (10 mg/kg). Our results show that exposure to particulate matter generates a time-dependent pattern of gene expression. From the 8799 genes or expressed sequence tags tested, we see that 132 genes were up- or downregulated shortly after exposure (i.e., 2-6 h), whereas after 15-21 h and 24-40 h, 46 and 56 genes showed altered expression, respectively. Focusing on the earliest point, 99 of the 132 genes were identified as unique. They include genes involved in an oxidative stress response (hemeoxygenase-1, metallothioneins, and thioredoxin reductase), an inflammatory response macrophage inflammatory protein-2, and tumor necrosis factor alpha), transcription factors belonging to the activating protein-1 family, and genes involved in cardiovascular functions. The present study, although not representing an ambient situation, is used to identify the biological pathways implicated in the initial injury response to PM exposure. Using Affymetrix chips, this study shows time-dependent gene expression, it identifies many genes that can be affected by exposure to particulate matter, and it confirms the involvement of oxidative stress in particulate-matter-related effects.