Effects of smoking marijuana, tobacco or cocaine alone or in combination on DNA damage in human alveolar macrophages

Role of Cannabinoids in Oral Cancer

Cannabinoids have incited scientific interest in different conditions, including malignancy, due to increased exposure to cannabis. Furthermore, cannabinoids are increasingly used to alleviate cancer-related symptoms. This review paper aims to clarify the recent findings on the relationship between cannabinoids and oral cancer, focusing on the molecular mechanisms that could link cannabinoids with oral cancer pathogenesis. In addition, we provide an overview of the current and future perspectives on the management of oral cancer patients using cannabinoid compounds. Epidemiological data on cannabis use and oral cancer development are conflicting. However, in vitro studies assessing the effects of cannabinoids on oral cancer cells have unveiled promising anti-cancer features, including apoptosis and inhibition of cell proliferation. Downregulation of various signaling pathways with anti-cancer effects has been identified in experimental models of oral cancer cells exposed to cannabinoids. Furthermore, in some countries, several synthetic or phytocannabinoids have been approved as medical adjuvants for the management of cancer patients undergoing chemoradiotherapy. Cannabinoids may improve overall well-being by relieving anxiety, depression, pain, and nausea. In conclusion, the link between cannabinoid compounds and oral cancer is complex, and further research is necessary to elucidate the potential risks or their protective impact on oral cancer.

Genotoxicity of Marijuana in Mono-Users

Marijuana (Cannabis sp.) is among the most recurred controlled substances in the world, and there is a growing tendency to legalize its possession and use; however, the genotoxic effects of marijuana remain under debate. A clear definition of marijuana's genotoxic effects remains obscure by the simultaneous consumption of tobacco and other recreational substances. In order to assess the genotoxic effects of marijuana and to prevent the bias caused by the use of substances other than cannabis, we recruited marijuana users that were sub-divided into three categories: (1) users of marijuana-only (M), (2) users of marijuana and tobacco (M+T), and (3) users of marijuana plus other recreative substances or illicit drugs (M+O), all the groups were compared against a non-user control group. We quantified DNA damage by detection of γH2AX levels and quantification of micronuclei (MN), one of the best-established methods for measuring chromosomal DNA damage. We found increased levels of γH2AX in peripheral blood lymphocytes from the M and M+T groups, and increased levels of MNs in cultures from M+T group. Our results suggest a DNA damage increment for M and M+T groups but the extent of chromosomal damage (revealed here by the presence of MNs and NBuds) might be related to the compounds found in tobacco. We also observed an elevated nuclear division index in all marijuana users in comparison to the control group suggesting a cytostatic dysregulation caused by cannabis use. Our study is the first in Mexico to assess the genotoxicity of marijuana in mono-users and in combination with other illicit drugs.

Addictions Causing Head-and-Neck Cancers

Head-and-neck cancers pose a serious economic burden, with most countries investing significant resources to reduce the incidence, primarily focusing on understanding addictive etiologies. The traditional literature focused on tobacco and alcohol use, with few studies on contemporary factors such as e-cigarette, waterpipe smoking, and human papillomavirus. This article attempts to collate and present an update on the globally identified etiologic factors.

The aim of this study was to identify and review the addictive etiologic factors causing head-and-neck cancers.

An electronic search was performed on Medline, Embase, and Google Scholar to identify the etiologies causing head-and-neck cancers and narrowed down on those driven by addiction. Further, we identified their constituents, mechanism of action, and the risks attributable to various forms of products.

Substances identified included smoked and chewed tobacco, alcohol, mate, marijuana, areca nut and betel quid, and viruses. An alarming majority of youth are now utilizing these substances. Furthermore, migrant movements have led to the spread of traditional practices across the regions, especially from the Asian subcontinent.

Ironically, despite modern advances and technology, we still see that a large proportion of population succumb to these cancers, emphasizing the need for more effective and targeted policies to combat this menace at the grassroots level.

Genomic Instability in Peripheral Blood and Buccal Mucosal Cells of Marijuana Smokers: The Impact of Tobacco Smoke

BACKGROUND

The aim of this study was to evaluate cytotoxic, mutagenic and genotoxic effects on buccal mucosa and peripheral blood cells from marijuana and tobacco smokers.

METHODS

For this purpose, a total of 45 volunteers were distributed into four groups: CTRL group (control): individuals who did not smoke marijuana or tobacco (n = 11); Group M: Marijuana smokers (n = 13); Group T: Tobacco smokers (n = 13); Group M + T: Smokers of both marijuana and tobacco (n = 08).

RESULTS

Smokers of both marijuana and tobacco led an increase of micronucleated cells on buccal mucosa when compared to control group. The occurrence of karyolysis showed significant changes in this group as well. The comet assay data revealed genetic damage in peripheral blood cells for all groups of smokers.

CONCLUSION

In summary, our results showed that marijuana and /or tobacco are able to induce genetic damage and cytotoxicity in oral and peripheral blood cells.

A review of the additive health risk of cannabis and tobacco co-use

INTRODUCTION

Cannabis and tobacco are the most widely used substances, and are often used together. The present review examines the toxicant exposure associated with co-use (e.g., carbon monoxide, carcinogens), co-use via electronic nicotine delivery systems (ENDS), and problematic methodological issues present across co-use studies.

METHOD

An extensive literature search through PubMed was conducted and studies utilizing human subjects and in vitro methods were included. Keywords included tobacco, cigarette, e-cigarette, ENDS, smoking, or nicotine AND marijuana OR cannabis OR THC.

RESULTS

Co-use may pose additive risk for toxicant exposure as certain co-users (e.g., blunt users) tend to have higher breath carbon monoxide levels and cannabis smoke can have higher levels of some carcinogens than tobacco smoke. Cannabis use via ENDS is low and occurs primarily among established tobacco or cannabis users, but its incidence may be increasing and expanding to tobacco/cannabis naïve individuals. There are several methodological issues across co-use research including varying definitions of co-use, sample sizes, lack of control for important covariates (e.g., time since last cigarette), and inconsistent measurement of outcome variables.

CONCLUSIONS

There are some known additive risks for toxicant exposure as a result of co-use. Research utilizing consistent methodologies is needed to further establish the additive risk of co-use. Future research should also be aware of novel technologies (e.g., ENDS) as they likely alter some toxicant exposure when used alone and with cannabis.

Tobacco and e-cigarette products initiate Kupffer cell inflammatory responses

Kupffer cells are liver resident macrophages that are responsible for screening and clearing blood of pathogens and foreign particles. It has recently been shown that Kupffer cells interact with platelets, through an adhesion based mechanism, to aid in pathogen clearance and then these platelets re-enter the general systemic circulation. Thus, a mechanism has been identified that relates liver inflammation to possible changes in the systemic circulation. However, the role that Kupffer cells play in cardiovascular disease initiation/progression has not been elucidated. Thus, our objective was to determine whether or not Kupffer cells are responsive to a classical cardiovascular risk factor and if these changes can be transmitted into the general systemic circulation. If Kupffer cells initiate inflammatory responses after exposure to classical cardiovascular risk factors, then this provides a potential alternative/synergistic pathway for cardiovascular disease initiation. We aimed to elucidate the prevalence of this potential pathway. We hypothesized that Kupffer cells would initiate a robust inflammatory response after exposure to tobacco cigarette or e-cigarette products and that the inflammatory response would have the potential to antagonize other salient cells for cardiovascular disease progression. To test this, Kupffer cells were incubated with tobacco smoke extracts, e-cigarette vapor extracts or pure nicotine. Complement deposition onto Kupffer cells, Kupffer cell complement receptor expression, oxidative stress production, cytokine release and viability and density were assessed after the exposure. We observed a robust inflammatory response, oxidative stress production and cytokine release after Kupffer cells were exposed to tobacco or e-cigarette extracts. We also observed a marginal decrease in cell viability coupled with a significant decrease in cell density. In general, this was not a function of the extract formulation (e.g. tobacco vs. e-cigarette products or the formulation of the cigarette product). These results indicate that Kupffer cells are responsive to classical cardiovascular risk factors and that an inflammatory response is initiated that may pass into the general systemic circulation.

Marijuana: respiratory tract effects

Marijuana is the most commonly used drug of abuse in the USA. It is commonly abused through inhalation and therefore has effects on the lung that are similar to tobacco smoke, including increased cough, sputum production, hyperinflation, and upper lobe emphysematous changes. However, at this time, it does not appear that marijuana smoke contributes to the development of chronic obstructive pulmonary disease. Marijuana can have multiple physiologic effects such as tachycardia, peripheral vasodilatation, behavioral and emotional changes, and possible prolonged cognitive impairment. The carcinogenic effects of marijuana are unclear at this time. Studies are mixed on the ability of marijuana smoke to increase the risk for head and neck squamous cell carcinoma, lung cancer, prostate cancer, and cervical cancer. Some studies show that marijuana is protective for development of malignancy. Marijuana smoke has been shown to have an inhibitory effect on the immune system. Components of cannabis are under investigation as treatment for autoimmune diseases and malignancy. As marijuana becomes legalized in many states for medical and recreational use, other forms of tetrahydrocannabinol (THC) have been developed, such as food products and beverages. As most research on marijuana at this time has been on whole marijuana smoke, rather than THC, it is difficult to determine if the currently available data is applicable to these newer products.

Marijuana smoke condensate induces p53-mediated apoptosis in human lung epithelial cells

Since the largely abused worldwide used of marijuana, there have been many ongoing debates regarding the adverse health effects of marijuana smoking. Marijuana smoking was recently proved to cause pulmonary toxicity by inducing genotoxic effects or generating reactive oxygen species. Because p53, a tumor suppressor gene, has an important pathophysiologic role in the regulation of lung epithelial cell DNA damage responses, we hypothesized that p53 may be involved in the oxidative stress-mediated apoptosis induced by marijuana smoking. First, we confirmed that marijuana smoke condensate (MSC) induces oxidative stress in BEAS-2B cells. We observed that reactive oxygen species (ROS) generation was increased by MSC in the DCFH-DA assay. Also, antioxidant enzyme (superoxide dismutase, catalase) activity and their mRNA expressions were up-regulated by MSC. Second, we investigated p53 involvement in the MSC-induced apoptotic pathway in BEAS-2B cells. The results showed that MSC increased caspase-3 activation and DNA fragmentation as markers of apoptosis. In addition, the mRNA levels of apoptosis-related genes (p53 and Bax) were increased by MSC and phospho-p53, along with the increase of Bax protein expression by MSC. Apoptosis and apoptosis-related gene expression were partially blocked by an inhibitor of p53-dependent transcriptional activation (pifithrin-α). The results indicate that p53 plays a role in MSC-induced apoptosis. Taken together, the findings of the present study suggest that MSC partially induces p53-mediated apoptosis through ROS generation in human lung epithelial cells and this may have broader implications for our understanding of pulmonary diseases.

A global toxicogenomic analysis investigating the mechanistic differences between tobacco and marijuana smoke condensates in vitro

Like tobacco smoking, habitual marijuana smoking causes numerous adverse pulmonary effects. However, the mechanisms of action involved, especially as compared to tobacco smoke, are still unclear. To uncover putative modes of action, this study employed a toxicogenomics approach to compare the toxicological pathways perturbed following exposure to marijuana and tobacco smoke condensate in vitro. Condensates of mainstream smoke from hand-rolled tobacco and marijuana cigarettes were similarly prepared using identical smoking conditions. Murine lung epithelial cells were exposed to low, medium and high concentrations of the smoke condensates for 6h. RNA was extracted immediately or after a 4h recovery period and hybridized to mouse whole genome microarrays. Tobacco smoke condensate (TSC) exposure was associated with changes in xenobiotic metabolism, oxidative stress, inflammation, and DNA damage response. These same pathways were also significantly affected following marijuana smoke condensate (MSC) exposure. Although the effects of the condensates were largely similar, dose-response analysis indicates that the MSC is substantially more potent than TSC. In addition, steroid biosynthesis, apoptosis, and inflammation pathways were more significantly affected following MSC exposure, whereas M phase cell cycle pathways were more significantly affected following TSC exposure. MSC exposure also appeared to elicit more severe oxidative stress than TSC exposure, which may account for the greater cytotoxicity of MSC. This study shows that in general MSC impacts many of the same molecular processes as TSC. However, subtle pathway differences can provide insight into the differential toxicities of the two complex mixtures.

The Role of p53 in Marijuana Smoke Condensates-induced Genotoxicity and Apoptosis

OBJECTIVES

Marijuana is one of the most frequently abused drug in Korea and its adverse health effects are controversial. p53 is known to be crucial in regulating the DNA damage responses, and adverse effects can occur when it is regulated by marijuana smoke. We evaluated a role of p53 on genotoxic effect and apoptosis in lung cancer cells exposed to marijuana smoke condensates (MSCs).

METHODS

The p53-related genotoxicity and apoptosis of MSCs were evaluated using in vitro bioassay, viz., comet assay, cytokinesis-block micronucleus assay and apoptosis assay. We used two cell lines with differential p53 expression (p53-wildtype (WT) H460 and p53-null H1299).

RESULTS

MSCs significantly increased DNA breakages and chromosomal changes in p53-WT H460 and p53-null H1299 cells. The genotoxicity induced by MSCs in p53-null H1299 cells showed greater sensitivity than p53-WT H460 cells. Moreover, MSCs showed a significant increase in reactive oxygen species production and apoptosis. The apoptotic responses induced by MSCs were higher in p53-WT H460 cells than in p53-null H1299 cells. Significantly increased mRNA expression or apoptosis related genes, including p53, caspase-3, and Bax/Bcl-2 ratio were observed in the p53-WT H460 cells exposed to MSCs.

CONCLUSIONS

These results suggest that MSCs induce DNA/chromosomal damages and apoptosis in human lung cancer cells and p53 plays an important role in the cellular response to MSCs. The present study may have border implications for our understanding of pulmonary diseases.

Evaluation of the DNA damaging potential of cannabis cigarette smoke by the determination of acetaldehyde derived N2-ethyl-2'-deoxyguanosine adducts

Acetaldehyde is an ubiquitous genotoxic compound that has been classified as a possible carcinogen to humans. It can react with DNA to form primarily a Schiff base N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dG) adduct. An online column-switching valve liquid chromatography tandem mass spectrometry (LC-MS/MS) selected reaction monitoring (SRM) method was developed for the determination of N(2)-ethylidene-dG adducts in DNA following reduction with sodium cyanoborohydride (NaBH(3)CN) to the chemically stable N(2)-ethyl-2'-deoxyguanosine (N(2)-ethyl-dG) adduct. Accurate quantitation of the adduct was obtained by the addition of the [(15)N(5)]N(2)-ethyl-dG stable isotope-labeled internal standard prior to enzymatic hydrolysis of the DNA samples to 2'-deoxynucleosides with the incorporation of NaBH(3)CN in the DNA hydrolysis buffer. The method required 50 microg of hydrolyzed DNA on column for the analysis, and the limit of detection for N(2)-ethyl-dG was 2.0 fmol. The analysis of calf thymus DNA treated in vitro with acetaldehyde (ranging from 0.5 to 100 mM) or with the smoke generated from 1, 5, and 10 cannabis cigarettes showed linear dose-dependent increases in the level of N(2)-ethyl-dG adducts (r = 0.954 and r = 0.999, respectively). Similar levels (332.8 +/- 21.9 vs 348.4 +/- 19.1 adducts per 10(8) 2'-deoxynucleosides) of N(2)-ethyl-dG adducts were detected following the exposure of calf thymus DNA to 10 tobacco or 10 cannabis cigarettes. No significant difference was found in the levels of N(2)-ethyl-dG adducts in human lung DNA obtained from nonsmokers (n = 4) and smokers (n = 4) with the average level observed as 13.3 +/- 0.7 adducts per 10(8) 2'-deoxynucleosides. No N(2)-ethyl-dG adducts were detected in any of the DNA samples following analysis with the omission of NaBH(3)CN from the DNA hydrolysis buffer. In conclusion, these results provide evidence for the DNA damaging potential of cannabis smoke, implying that the consumption of cannabis cigarettes may be detrimental to human health with the possibility to initiate cancer development.

Biomarkers of induced active and passive smoking damage

In addition to the well-known link between smoking and lung cancer, large epidemiological studies have shown a relationship between smoking and cancers of the nose, oral cavity, oropharynx, larynx, esophagus, pancreas, bladder, kidney, stomach, liver, colon and cervix, as well as myeloid leukemia. Epidemiological evidence has reported a direct link between exposure of non-smokers to environmental tobacco smoke and disease, most notably, lung cancer. Much evidence demonstrates that carcinogenic-DNA adducts are useful markers of tobacco smoke exposure, providing an integrated measurement of carcinogen intake, metabolic activation, and delivery to the DNA in target tissues. Monitoring accessible surrogate tissues, such as white blood cells or bronchoalveolar lavage (BAL) cells, also provides a means of investigating passive and active tobacco exposure in healthy individuals and cancer patients. Levels of DNA adducts measured in many tissues of smokers are significantly higher than in non-smokers. While some studies have demonstrated an association between carcinogenic DNA adducts and cancer in current smokers, no association has been observed in ex or never smokers. The role of genetic susceptibility in the development of smoking related-cancer is essential. In order to establish whether smoking-related DNA adducts are biomarkers of tobacco smoke exposure and/or its carcinogenic activity we summarized all data that associated tobacco smoke exposure and smoking-related DNA adducts both in controls and/or in cancer cases and studies where the effect of genetic polymorphisms involved in the activation and deactivation of carcinogens were also evaluated. In the future we hope we will be able to screen for lung cancer susceptibility by using specific biomarkers and that subjects of compared groups can be stratified for multiple potential modulators of biomarkers, taking into account various confounding factors.

Cannabis smoke condensate II: influence of tobacco on tetrahydrocannabinol levels

Medicinal cannabis has attracted a lot of attention in recent times. Various forms of administration are used, of which smoking is very common but the least desirable. Smoking cannabis generates a large amount of unwanted side products, of which carcinogenic compounds are the most dangerous. A common practice among recreational drug users, and to a lesser degree patients who uses cannabis as medicine, is to mix the cannabis material with commercially available tobacco in order to increase the burning efficiency of the cigarette and to reduce the overall costs of the cigarette. In this study cannabis material has been mixed with tobacco in order to determine whether tobacco has an influence on the amount of and ratio between tetrahydrocannabinol (THC), cannabigerol (CBG), and cannabinol (CBN) administered while smoking. A small-scale smoking machine has been used and cannabis mixed with various ratios of tobacco was smoked. The trapped smoke was quantitatively analyzed by high-performance liquid chromatography (HPLC) and the amount of THC, CBG, and CBN was determined for each cigarette. We have found that tobacco increases the amount of THC inhaled per gram of cannabis from 32.70 +/- 2.29 mg/g for a 100% cannabis cigarette to 58.90 +/- 2.30 mg/g for a 25% cannabis cigarette. This indicates that tobacco increases the vaporization efficiency of THC by as much as 45% under the conditions tested.

Cannabis use and cancer of the head and neck: case-control study

Objective

To investigate whether cannabis smoking increases the risk of head and neck cancer.

Design

Case-control study.

Subjects and Methods

Cases of head and neck cancer ≤55 years identified from hospital databases and the Cancer Registry, and controls randomly selected from the electoral roll completed interviewer-administered questionnaires. Logistic regression was used to estimate the relative risk of head and neck cancer.

Results

There were 75 cases and 319 controls. An increased risk of cancer was found with increasing tobacco use, alcohol consumption, and decreased income but not increasing cannabis use. The highest tertile of cannabis use (>8.3 joint years) was associated with a nonsignificant increased risk of cancer (relative risk = 1.6, 95% confidence interval, 0.5-5.2) after adjustment for confounding variables.

Conclusions

Cannabis use did not increase the risk of head and neck cancer; however, because of the limited power and duration of use studied, a small or longer-term effect cannot be excluded.

Antioxidant and antigenotoxic activities of Angelica keiskei, Oenanthe javanica and Brassica oleracea in the Salmonella mutagenicity assay and in HCT116 human colon cancer cells

Epidemiological studies indicate that consumption of green-yellow vegetables rich in chlorophyll, vitamin C, vitamin E, and carotenoids reduce the risk of cancer. We sought to examine the antigenotoxic and antioxidant properties of chlorophyll-rich methanol extracts of Angelica keiskei, Oenanthe javanica, and Brassica oleracea (kale). In the Salmonella mutagenicity assay, A. keiskei caused dose-dependent inhibition against three heterocyclic amine mutagens in the presence of S9, O. javanica was antimutagenic only at the highest concentration in the assay (2 mg/plate), and B. oleracea showed no consistent inhibitory activity at non-toxic levels. None of the extracts were effective against three direct-acting mutagens in the absence of S9. Extracts of A. keiskei and, to a lesser extent O. javanica, inhibited two of the major enzymes that play a role in the metabolic activation of heterocyclic amines, based on ethoxyresorufin-O-deethylase and methoxyresorufin-O-demethylase assays in vitro. All three plant extracts were highly effective in assays which measured ferric reducing/antioxidant power, oxygen radical absorbance capacity, and Fe2+/H2O2-mediated DNA nicking. Finally, using the 'comet' assay, all three plant extracts protected against H2O2-induced genotoxic damage in human HCT116 colon cancer cells. These findings provide support for the antigenotoxic and antioxidant properties of chlorophyll-rich extracts of A. keiskei, O. javanica, and B. oleracea, through mechanisms that include inhibition of carcinogen activation and scavenging of reactive oxygen species.

Cocaine cardiovascular toxicity

Cocaine abuse kills thousands every year. Preexisting coronary artery disease appears to account for many of the deaths, but often the mechanism is much more complex. There exists a widely held but utterly mistaken notion that cocaine-related deaths are due to drug overdose. Except in the case of drug couriers ("body packers") with massive drug exposure, death is not dose related, and cocaine blood levels cannot be used to predict toxicity. Most deaths occur after prolonged drug use, which initiates a series of changes at the molecular, cellular, and tissue levels. All of these changes favor sudden death. Potentially lethal myocardial alterations include hypertrophy, fibrosis, and microangiopathy. Recently it has become clear that genetic causes, such as fully or partially expressed congenital long QT syndrome, may also play a role. The relative importance of each of these factors is reviewed.

The safety of cannabinoids for the treatment of multiple sclerosis

The evidence for the therapeutic efficacy of cannabinoids in the treatment of multiple sclerosis (MS) is increasing but is not as yet convincing. Although several trials have reported no significant effect, the majority of the evidence which supports a beneficial effect on spasticity and pain is based on subjective measurements in trials where unblinding was likely to be a problem. The available clinical trial data suggest that the adverse side effects associated with using cannabis-based medicinal extracts (CBMEs) are generally mild, such as dry mouth, dizziness, somnolence, nausea and intoxication, and in no case did toxicity develop. However, most of these trials were run over a period of months and it is possible that other adverse side effects, not seen in these short-term studies, could develop with long-term use. Despite the evidence that cannabinoids can disrupt cognitive function and promote depression, on the basis of current data, such adverse effects seem unlikely to be associated with the use of CBMEs. Likewise, there is no evidence to suggest that their effects on balance and motor control, or immune function, may be clinically significant. There is, however, reason to be concerned about the use of therapeutic cannabinoids by people predisposed to psychosis and by pregnant women, given the increasing evidence of their adverse effects on the fetus. In conclusion, given the modest therapeutic effects of cannabinoids demonstrated so far, and the risk of long-term adverse side effects, there is reason to be cautious about their use in the treatment of MS.

Marijuana Use and Risk of Oral Squamous Cell Carcinoma

Previous laboratory investigations, case reports, and a hospital-based case-control study have suggested that marijuana use may be a risk factor for squamous cell head and neck cancer. We conducted a population-based case-control study to determine whether marijuana use is associated with the development of oral squamous cell carcinoma (OSCC). Case subjects (n = 407) were 18-65-year-old residents of three counties in western Washington State who were newly diagnosed with OSCC from 1985 through 1995. Control subjects (n = 615), who were similar to the cases with respect to age and sex, were selected from the general population using random-digit telephone dialing. Lifetime histories of marijuana use and exposure to known OSCC risk factors were ascertained using a structured questionnaire. Information on genetic polymorphisms in glutathione S-transferase enzymes was obtained from assays on participant DNA. Odds ratios for associations with features of marijuana use were adjusted for sex, education, birth year, alcohol consumption, and cigarette smoking. A similar proportion of case subjects (25.6%) and control subjects (24.4%) reported ever use of marijuana (adjusted odds ratio, 0.9; 95% confidence interval, 0.6-1.3). There were no trends in risk observed with increasing duration or average frequency of use or time since first or last use. No subgroup defined by known or suspected OSCC risk factors (age, cigarette smoking, alcohol consumption, and genetic polymorphisms) showed an increased risk. Marijuana use was not associated with OSCC risk in this large, population-based study.

Pulmonary effects of illicit drug use

The lungs are at considerable risk from the use of injected or inhaled illicit drugs. The extent and clinical significance of illicit drug induced lung damage is not known completely. Drug use leads to an increase in infectious pulmonary disease, historically in relation to nonsterile injection techniques, and, more recently, in relation to HIV infection and its pulmonary manifestations. Barotrauma related to "smoking topography" or errant injections also represents a real risk of drug use. Although granulomatous disease that involves the pulmonary vasculature and interstitium is probably common in injection drug users, the clinical consequence of such is difficult to estimate. What effect smoked or injected illicit drugs have on short- and long-term pulmonary function also is hard to ascertain. The ubiquitous use of tobacco among users of illicit drugs certainly has confounding effects. Given that illicit drug use is common and that the "popular" drugs of abuse change from generation to generation, the pulmonary physician must remain informed about, and alert for, the effects of drugs of abuse.

Epigallocatechin gallate, a potential immunomodulatory agent of tea components, diminishes cigarette smoke condensate-induced suppression of anti-Legionella pneumophila activity and cytokine responses of alveolar macrophages

Even though cigarette smoking has been shown to suppress immune responses in the lungs, little is known about the effect of cigarette smoke components on respiratory infections. In the present study, the effects of cigarette smoke condensate (CSC) on bacterial replication in alveolar macrophages and the immune responses of macrophages to infection were examined. Furthermore, a possible immunotherapeutic effect of epigallocatechin gallate (EGCg), a major form of tea catechins, on the CSC-induced suppression of antimicrobial activity and immune responses of alveolar macrophages was also determined. The treatment of murine alveolar macrophage cell line (MH-S) cells with CSC significantly enhanced the replication of Legionella pneumophila in macrophages and selectively down-regulated the production of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) induced by bacterial infection. The treatment of macrophages with EGCg not only overcame the CSC-induced suppression of antimicrobial activity but also strengthened the resistance of macrophages to infection. EGCg also markedly up-regulated the CSC-suppressed IL-6 and TNF-alpha production by macrophages in response to infection. The results of exogenous TNF-alpha treatment and neutralization treatment with anti-TNF-alpha and anti-gamma-interferon (IFN-gamma) antibodies and the determination of IFN-gamma mRNA levels indicate that CSC-suppressed macrophages can be activated by EGCg to inhibit L. pneumophila growth by up-regulation of TNF-alpha and IFN-gamma production. Thus, this study revealed that CSC selectively alters the immune responses of macrophages to L. pneumophila infection and leads to an enhancement of bacterial replication in macrophages. In addition, the tea catechin EGCg can diminish such suppressive effects of CSC on alveolar macrophages.

Induction and regulation of the carcinogen-metabolizing enzyme CYP1A1 by marijuana smoke and delta (9)-tetrahydrocannabinol

Induction of the carcinogen-metabolizing enzyme cytochrome P4501A1 (CYP1A1) is a key step in the development of tobacco-related cancers. To determine if marijuana smoke activates CYP1A1, a murine hepatoma cell line expressing an inducible CYP1A1 gene (Hepa-1) was exposed in vitro to tar extracts prepared from either tobacco, marijuana, or placebo marijuana cigarettes. Marijuana tar induced higher levels of CYP1A1 messenger RNA (mRNA) than did tobacco tar, yet resulted in much lower CYP1A1 enzyme activity. These differences between marijuana and tobacco were primarily due to Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the psychoactive component of marijuana. Here we show that Delta(9)-THC acts through the aryl hydrocarbon receptor complex to activate transcription of CYP1A1. A 2-microg/ml concentration of Delta(9)-THC produced an average 2.5-fold induction of CYP1A1 mRNA, whereas a 10- microg/ml concentration of Delta(9)-THC produced a 4.3-fold induction. No induction was observed in Hepa-1 mutants lacking functional aryl-hydrocarbon receptor or aryl-hydrocarbon receptor nuclear translocator genes. At the same time, Delta(9)-THC competitively inhibited the CYP1A1 enzyme, reducing its ability to metabolize other substrates. Spiking tobacco tar with Delta(9)-THC resulted in a dose-dependent decrease in the ability to generate CYP1A1 enzyme activity as measured by the ethoxyresorufin-o-deethylase (EROD) assay. This inhibitory effect was confirmed by Michaelis-Menton kinetic analyses using recombinant human CYP1A1 enzyme expressed in insect microsomes. This complex regulation of CYP1A1 by marijuana smoke and the Delta(9)-THC that it contains has implications for the role of marijuana as a cancer risk factor.

Recent trends in lung cancer mortality in the United States

BACKGROUND

Previous age-period-cohort analyses of lung cancer incidence and mortality rates in the United States have demonstrated a decrease in risk by birth cohort through 1950, consistent with declining trends in smoking prevalence. This study was conducted to examine recent lung cancer trends, including trends among the cohorts born after 1950.

METHODS

Lung cancer mortality rates from 1970 through 1997 for whites aged 24--83 years and for blacks aged 30--83 years were investigated. Using age--period--cohort analyses with 2-year age and 2-year calendar-period intervals, we examined changes in the slope of the trends in birth-cohort and calendar-period effects. All statistical tests are two-sided.

RESULTS

There was an unexpected, statistically significant moderation in the rate of decrease of the birth-cohort trend in lung cancer mortality for whites born after 1950, with a corresponding smaller and statistically nonsignificant moderation for blacks. These data are consistent with smoking initiation rates: Rates of both cigarette and marijuana smoking initiation increased for children aged 12--17 years from 1965 through 1977. There was a statistically significant decrease in the slope of the calendar-period trend for lung cancer mortality in 1990 for both whites and blacks that was observed primarily in people 55 years of age and older.

CONCLUSIONS AND IMPLICATIONS

The birth-cohort pattern of lung cancer mortality after 1950 appears to reflect the early impact of teenage cigarette smoking on lung cancer risk in people under the age of 45 years, although a contribution from marijuana smoking cannot be ruled out. This result provides additional support for increasing smoking cessation and prevention programs for teenagers. The calendar-period decrease in lung cancer mortality after 1990 may reflect the long-term benefits of reductions in tobacco carcinogens in cigarettes and increases in smoking cessation beginning around 1960.

Chronic inhaled cocaine abuse may predispose to the development of pancreatic adenocarcinoma

BACKGROUND

The acute and chronic effects of cocaine over various organ systems have been well documented. A more recent approach to the effects of this drug has focused on the immunological consequences of its exposure, with results that indicate a possible carcinogenic effect.

METHODS

A chart review was made in order to search for young pancreatic adenocarcinoma patients (arbitrarily defined as younger than 40) who made use of inhaled cocaine. This age was chosen because of a higher probability of cocaine addiction than at older ages.

RESULTS

Of the 198 patients with pancreatic adenocarcinoma, 13 were younger than 40 years (range 19 to 37) and 5 of these had abused inhaled cocaine for about a decade. One patient had abused marijuana, and there was no information on drug usage in the other 7 patient charts.

CONCLUSION

Although this is a very small series, we believe there might be a possibility that chronic cocaine exposure predisposes to the development of pancreatic adenocarcinoma. Further studies are necessary.

Mutagenicity, developmental toxicity and carcinogenicity of cannabis

Data on the mutagenicity, developmental toxicity and carcinogenicity of cannabis are reviewed in this article. The available evidence on the possible mutagenic effects of cannabinoids is still inconclusive. There is no consensus on the induction of point mutations, while some experimental results suggest that cannabinoids may cause chromosomal damage. Concerning the developmental effects of cannabis, an increased embryolethality and somatic growth retardation have been observed in animals, as well as changes in motor behaviour, after perinatal exposure to cannabinoids. An elevated risk for infertility has been suggested for women smoking marijuana. On the other hand, intrauterine exposure to cannabinoids may be followed by changes of behaviour later in childhood. Finally, the experimental work concerning the possible carcinogenic action of cannabinoids has shown that cannabis acts as a tumour promotor in animals. Epidemiological studies have incriminated cannabis smoking for the development of head and neck carcinomas and for carcinomas of the respiratory tract in humans, but several confounding factors have rendered this evidence inconclusive. At least part of the great popularity of cannabis smoking is due to the widespread belief that it is harmless. However, the studies presented in this review show that, despite their low acute toxicity profile, cannabinoids represent several risks in terms of chronic toxicity.

Marijuana. Respiratory tract effects

Daily marijuana smoking has been clearly shown to have adverse effects on pulmonary function and produce respiratory symptomatology (cough, wheeze, and sputum production) similar to that of tobacco smokers. Based on the tobacco experience, decrements in pulmonary function may be predictive of the future development of chronic obstructive pulmonary disease (COPD). However, in the absence of alpha-1-antitrypsin deficiency, the habitual marijuana-only smoker would likely have to smoke 4-5 joints per day for a span of at least 30 yr in order to develop overt manifestations of COPD. The mutagenic/carcinogenic properties of marijuana smoke are also well-established. The potential for induction of laryngeal, oropharyngeal, and possibly bronchogenic carcinoma from marijuana has been documented by several case reports and observational series. Despite this, a relative risk ratio for the development of these tumors has not yet been quantified. Based on a higher frequency of case reports for upper airway cancer compared to bronchogenic carcinoma, marijuana smoking may have a more deleterious effect on the upper respiratory tract. However, this hypothesis remains speculative at best, pending confirmation by longitudinal studies.