Protective effects of baicalin on diethyl nitrosamine-induced liver cirrhosis by suppressing oxidative stress and inflammation.

Baicalin (BA) is a natural product extract with anti-inflammatory, antioxidant, and hepatoprotective properties. Given that the exact underlying mechanisms responsible for the impact of BA on liver cirrhosis remain ambiguous, a detailed investigation is sorely needed. Accordingly, a rat liver cirrhosis model was established via the intraperitoneal injection of diethyl nitrosamine (DEN, 100 mg/kg). Following the modeling, these rats were given BA (100 mg/kg) or N-acetylcysteine (NAC, 150 mg/kg) alone or in combination. The pathological morphology of rat liver tissues in each group was observed by hematoxylin and eosin staining and Masson's trichrome staining. The expression of fibrosis-related proteins was evaluated by Western blot, and the levels of liver function-related biochemical indexes, oxidative stress-related indexes, and inflammatory factors in the serum by enzyme-linked immunosorbent assays (ELISA). The level of mitochondrial reactive oxygen species was measured by flow cytometry. The results depicted that in the rat model of DEN-induced liver cirrhosis, BA reduced the expression of fibrosis-related proteins (collagen type I alpha 1, α-smooth muscle actin, and transforming growth factor-ß1), thereby alleviating the structural fibrosis of liver tissue. Furthermore, BA could diminish the level of mitochondrial reactive oxygen species, and the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), interleukin (IL)-1ß, IL-6, tumor necrosis factor-α (TNF-α), and monocyte chemotactic protein-1 (MCP-1), while promoting albumin, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels. Notably, all these effects of BA above were strengthened following the combined treatment of BA and NAC. On the whole, BA suppresses liver fibrosis by inhibiting oxidative stress and inflammation, thereby exerting a hepatoprotective effect.

NITROSAMINES IN COMMONLY PRESCRIBED ANTIHYPERTENSIVES AND THE (UN)CONTROLLED DRUG-INDUCED SKIN CANCER: SIMULTANEOUS DEVELOPMENT OF CUTANEOUS MELANOMA AND MULTIPLE BCC AFTER CONCOMITANT ADMINISTRATION OF BISOPROLOL AND FUROSEMIDE.

The era of nitrosogenesis is the era that is conditioned by the permanent and prolonged intake of carcinogens/mutagens, also known as nitrosamines/NDSRIs in the context of polymedication/polycontamination in polymorbid patients. Until recently, the favoured and universally accepted thesis by the scientific community that polymorbidity determines the risk of developing cancer has been shown to be weakly substantiated and superseded by the more modern notion that: it is the polycontamination with carcinogens in the context of concomitant medication/ polymorbidity that determines to a large extent the risk of developing heterogeneous cancers, including skin cancer: keratinocytic and melanocytic. The FDA is the organization that first pulled back the curtain on the backstage back in 2018 on this topic. It was not until 2023 that the FDA again catalogued over 250 drugs that are affected by contamination with carcinogens/mutagens/NDSRIs having varying carcinogenic potencies graded between 1 to 5. The expectations of clinicians and patients globally at the moment remain hopeful that the diplomatic recommendations of regulators will soon be replaced by more restrictive regimes and sanctions. The reason for the need to clarify this issue quickly is due to the following circumstances: 1) The reassuring calls and analyses of the regulators that the minimum intake of carcinogens ( nitrosamines or intake within reference values) , could not become a threat to the health of patients even after 70 years of intake, appear to be rather inconsistent; 2) Lack of any official data on any drug batch that has at least been declared by the FDA/EMA (if declared at all) as potentially contaminated; 3) Another not insignificant reason is that a number of scientific publications are indicative of exactly the opposite: short-term concomitant intake of polycontaminated drugs leads to short-term cancer development while shortening cumulative survival and quality of life for those affected. Only the transparency of the results of checks carried out on the presence of carcinogens in drug batches can guarantee peace of mind, and this in turn can be guaranteed by the regulatory authorities. 4) In parallel, the number of clinical data indicating an association between the intake of potentially nitrosamine-contaminated drugs (mainly for high blood pressure, but not only) and - in particular - keratinocytic and/or melanocytic skin cancer is growing avalanche-like. The dramatic increase in skin cancer in general/ worldwide is in absolute contradiction to the continuous explanations that the most important factor in the generation of skin cancer is ultraviolet light and sunburn: the incidence of skin cancer is increasing despite the widespread intensive use of sunscreen protection creams, the lack of any sun exposure in certain groups of patients, and its occurrence in areas not exposed to solar radiation. It follows only that solar radiation is not the only and perhaps not the most important factor determining the occurrence and progression of skin cancer. We report another concomitant intake of potentially nitrosamine contaminated blood pressure medications: bisoprolol and furosemide, taken over a period of 7 years that resulted in the concurrent occurrence of a medium-thickness cutaneous melanoma and 2 basal cell carcinomas. Successful surgical treatment of the tumors was performed, and the role of concurrent administration of ˝hypothetical˝ class 4 carcinogens within the framework of polymedication, polycontamination, and polymorbidity is discussed.

NITROSOGENESIS OF SKIN (HUMAN) CANCER- THE HIDDEN TRUTH OF A NEVERENDING STORY: NITROSAMINE CONTAMINATION IN OLMESARTAN, VALSARTAN AND HCT AS MAIN RISK FACTOR FOR THE DEVELOPMENT OF KERATINOCYTE CANCER.

The pathogenesis of skin cancer remains shrouded in mystery. Nevertheless, a substantial amount of new data is now available to provide a logical explanation regarding the possible link between 1) the occurrence of single or multiple acquired/somatic mutations and 2) the generation and progression of skin cancer, as well as 3) the potential association of the above two facts with the availability of nitrosamines in drugs for hypertension, diabetes, gastritis, acne, tuberculosis, various other antibiotics, etc. The nitrosogenesis of skin cancer is slowly but surely being established as a significant concept that could not be ignored for longer periods of time. It should only be analysed in detail with a view to future prevention for the benefit of public health. The nitrosogenesis of skin cancer is slowly but surely being established as a significant concept that cannot be ignored for longer periods of time. It should only be analysed in detail with a view to future prevention for the benefit of public health. Although this information has been known for decades (but in relation to the development of other cancers), there is still no comparative analysis of the mutations that occur after ingestion of a particular mutagen, also known as nitrosamine. This analysis could to some extent highlight/support or reject to some extent the thesis of the role of nitrosamines and genetic instability leading to the subsequent generation of a malignant cell clone. The notion of skin cancer nitrosogenesis should become a priority concept very soon, but it should also become an evidential memory, a byword, and an equivalent of the ignorance with which modern civilization has treated its own health for decades within the processes of globalization. It is these processes that include nitrosamines as a major component of the "medicinal and nutritional menu" of patients. It remains unclear at present why regulatory authorities are making endless attempts to legalise the availability of a number of mutagens/human carcinogens in the most commonly distributed medicines worldwide. And to persuade "others" that there is no risk from their permanent, controlled and long-term intake. The newly introduced regulatory norms in practice concern the potential/permissive availability of nitrosamines in a serious number of drugs: drugs with radically different mechanisms of action such as: ranitidine, metformin, ACE inhibitors, beta blockers, thiazide diuretics, sartans, rifampicin, but also probably a number of others. However, the occurrence of identical, similar patterns of cancers (skin cancers) following their administration (after ingestion of different classes of drugs) makes the ubiquitous permissive availability of nitrosamines (in each class of these drugs) the most potent and most likely pathogenetic inducer of cancer. These comparative patterns of skin tumor occurrence should have even stronger evidentiary value than even so-called prospective follow-ups. Nitrosamines are and remain one of the best studied mutagens/carcinogens that can alter/modify the human genome. A fact underlined repeatedly over the years (also based on in vivo data, repeatedly ignored) and a fact that, according to the literature, concerns mainly tire industry workers (British rubber workers). It is in this category of patients and after exposure to high doses of nitrosamines (potential inhalation intake) that high mortality has been found in bladder, lung, stomach, oesophageal cancer, multiple myeloma, leukaemia, prostate cancer, pancreatic cancer, and liver cancer. Similar international observations (in vivo/Sweden) concerning intensive human exposure (Swedish rubber workers) to high doses of nitrosamines in a working atmosphere (inhalation type of carcinogen uptake) emphasize the resulting direct subsequent risk of other alarming symptoms such as: nasal bleeds, eye and throat symptoms, hoarseness, cough, nausea, headache, and altered levels of eosinophils and total immunoglobulin G (IgG), compared with unexposed patients. The neglect of these important observations over the years has led to the ubiquitous and currently difficult to counteract and unpunished prevalence of nitrosamines in even the most commonly distributed drugs worldwide (except in the food industry). It is precisely because of this fact that it should come as no surprise to anyone that there is new evidence of an avalanche in the number of new cancers after ingestion of potentially nitrosamine-contaminated preparations. Skin cancer could be seen in the near future precisely as a model of a side reaction after application or long-term contact with mutagens called nitrosamines. Based on the above, and wishing to add to the worldwide data on the heterogeneous cancers that occur after contact with nitrosamines, we draw the attention of the scientific community to the risk of developing keratinocytic cancer after ingestion of nitrosamine-contaminated drugs: sartans and thiazide diuretics. We believe that the role of the generic substance in these drugs could also contribute to some extent to the progression of an already present tumour branch, but this influence is rather minor and without significant clinical relevance. We present a patient who had been taking 2 sartans (valsartan/ olmesartan) over the years as monotherapy and in combination with hydrochlorothiazide, who developed over time and within this intake two forms of keratinocytic cancer: verrucous carcinoma and basal cell carcinoma. The focus of discussion concerns a newly introduced medical concept: nitrosogenesis of skin cancer. The detailed study of nitrosogenesis should be a major, primary task for regulators, researchers, clinicians, and pharmaceutical companies.

THE NITROSAMINE CONTAMINATION IN BETA BLOCKERS (BISOPROLOL/METOPROLOL), ACE INHIBITORS (LISINOPRIL/PERINDOPRIL), THIAZIDES DIURETICS (HCT), CALCIUM CHANNEL BLOCKERS (AMLODIPINE/FELODIPINE), SARTANS (CANDESARTAN) AND ТHE SUBSEQUENT SKIN CANCER DEVELOPMENT AND PROGRESSION: APOCALYPSE NOW.

The problem of contamination of the most commonly used medicines with nitrosamines is worsening worldwide. According to recent literature data, this "contamination" is the cause not only of skin cancer (keratinocytic/melanoma) but also of gastrointestinal neoplasms, brain tumours, neuroblastoma, rectal carcinoma, acute lymphoblastic leukaemia, and many others. It is these clinical manifestations that are associated with/ or already directly linked to the nitrosamine content of drugs and food products used by patients in previous periods. And it is this permissive availability/contamination that could prove to be the most likely, powerful inducer of acquired mutations underlying the worldwide cancer pandemic. Of further concern is the evidence of contamination of newer classes of medications by nitrosamines- namely: beta blockers, calcium antagonists and selective serotonin reuptake inhibitors (SSRIs). In practice, mankind faces the problem of certainly over 1 billion patients taking nitrosamine-contaminated drugs: 280 million patients with depression (antidepressants), over 1 billion patients with arterial hypertension (antihypertensive drugs), over half a billion patients with type 2 diabetes mellitus (oral antidiabetic drugs/metformin/ sitagliptin), over 4 billion patients with gastritis (ranitidine), over 5 million with tuberculosis (rifampicin), and probably a number of others. The calculations are apocalyptic, since even if only 20-30% of the groups were affected, the number of patients taking these drugs would, by a rough calculation, currently amount to over 1 billion. And there are certainly other classes of drugs yet to be announced. It is for this reason that we should not be surprised that the data on the development of keratinocyte cancer after intake of nitrosamine-contaminated preparations is growing at a breakneck pace. This data indirectly but strongly confirms the importance of a newly introduced concept in the medical science : Nitrosogenesis of skin cancer. A concept, until recently unknown, incomprehensible, but at the same time frightening and gradually accepted, imposing itself and which with each passing day is gaining more and more scientific significance and "visibility", "scientific tangibility, receptivity, and acceptability." This article presents, for the first time in the world literature, patients who developed single/multiple forms of keratinocytic cancer (partly in combination with melanoma precursors-dysplastic moles) after administration of two new classes of potentially nitrosamine-contaminated antihypertensive drugs: beta blockers (bisoprolol, metoprolol) and calcium antagonists (amlodipine, felodipine). For the first time in the scientific literature, the contributory pro-carcinogenic role of another potentially nitrosamine-contaminated ACE inhibitor- lisinopril , as well as that of candesartan: in the development of keratinocytic cancer is also discussed. For the first time in the world literature, the conclusion regarding the pathogenetic relationship between the intake of potentially contaminated drugs (from different drug groups) and cancer development is based on the model of the equivalent clinical manifestation of skin tumors (rather than on controlled long-term prospective analyses). Nitrosamine contamination in these drug groups appears to be the sole and major unifying factor or causative agent for these manifestations.

Dietary Phytochemicals as Potential Chemopreventive Agents against Tobacco-Induced Lung Carcinogenesis.

Lung cancer is the second most common cancer in the world. Cigarette smoking is strongly connected with lung cancer. Benzo[a]pyrene (BaP) and 4-(N-methyl-N-nitrosamine)-1-(3-pyridyl)-butanone (NNK) are the main carcinogens in cigarette smoking. Evidence has supported the correlation between these two carcinogens and lung cancer. Epidemiology analysis suggests that lung cancer can be effectively prevented through daily diet adjustments. This review aims to summarize the studies published in the past 20 years exploring dietary phytochemicals using Google Scholar, PubMed, and Web of Science databases. Dietary phytochemicals mainly include medicinal plants, beverages, fruits, vegetables, spices, etc. Moreover, the perspectives on the challenges and future directions of dietary phytochemicals for lung cancer chemoprevention will be provided. Taken together, treatment based on the consumption of dietary phytochemicals for lung cancer chemoprevention will produce more positive outcomes in the future and offer the possibility of reducing cancer risk in society.

MELANOMA AND DYSPLASTIC NEVI DEVELOPMENT AFTER RANITIDINE/RILMENIDINE/МOXONIDINE, LERCANIDIPINE, ROSUVASTATIN AND VERAPAMIL/TRANDOLAPRIL - NEW DATA/CASE SERIES. THE POTENTIAL ROLE OF NITROSAMINE/NDSRIS CONTAMINATION IN POLYMEDICATION AS SUBSTANTIAL SKIN CANCER TRIGGERING FACTOR.

The idea of drug-induced/exogenic Nitrosogenesis is driven by the possibility of prolonged exposure of the human body to the influence of nitrosamines within the drug intake - substances or contaminants that have been proven to be carcinogenic or mutagenic one.Until recently, there was a complete lack of data in the scientific literature on the relationship between cancer, polymedication and polycontamination with nitrosamines. In the last decade, melanoma has been described repeatedly in the medical literature as a possible side-effect within the intake of possibly with nitrosamines contaminated medications such as: Valsartan, Hydrochlorothiazide, Amlodipine, Nebivolol, Bisoprolol and Perindopril. However, the contribution of the currently presented new data (5 new patients) is also due to the establishment of the possible pathogenetic role (with respect to melanoma) of several completely new drugs, previously unknown to the scientific community (potentially/actually contaminated with carcinogens/nitrosamines), such as: Ranitidine, Rosuvastatin, Lercanidipine, Rilmenidine, Trandolapril, Moxonidine and Verapamil.The leading and connecting link in shared new and old drug combinations of heterogeneous drug classes (polymedication) and melanoma development and progression remains again one and the same: the possible availability of nitroso component in the frame of exogenous nitrosogenesis according to the official FDA lists of 2023.The number of drugs shared as contaminated with nitrosamines after whose intake melanomas occur is increasing. Nitrosogenesis remains a new beginning, a new understanding and new interpretation of the carcinogenesis concerning melanoma, but probably also of cancer in general. Its further elucidation looks more than promising and is yet to come. More than worrying at the moment remains the fact that the scientific community has to clarify if: 1) peak concentrations of nitrosamines or NDSRIs within the framework of monomedication or 2) normal concentrations within the polymedication (catalogued in the list of FDA/ 2023 as potentially contaminated with hypothetical carcinogens), could hide relatively short-term risk of the development of real tumors: cutaneous melanomas and/or their precursor lesions. The validation of the concept of Nitrosogenesis and its relationship to Сarcinogenesis, is achieved in practice on the basis of the following facts: that it is the occurrence of the same monomorphic clinical pattern (melanoma/dysplastic nevi), developing after the intake of drugs with different mechanism of action, contaminated with nitrosamines/NDSRIs. The unifying link between the intake of certain drugs and the development of certain tumours remains the presence of nitrosamines. Ingredients that are present in drug preparations, identified as availability and as carcinogenic potency, but not yet reflected in packaging or prescriptions. The question remains: why?

Combinatory lung tumor inhibition by myo-inositol and iloprost/rapamycin: association with immunomodulation.

Although both preclinical and clinical studies have suggested that myo-inositol (MI) may be a safe and effective lung cancer chemopreventive agent, its efficacy is moderate. To test whether the chemopreventive agents iloprost (IL) or rapamycin enhance the lung tumor inhibitory effects of MI, A/J mice were treated with the tobacco smoke carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and, beginning one week after the end of NNK treatment, given MI, IL, rapamycin, MI + IL or MI + rapamycin for 17 weeks. Analyses of the number and size of tumors on the surface of the lung have indicated that MI, IL, rapamycin, MI + IL and MI + rapamycin reduced the multiplicity of NNK-induced lung tumors by 41, 34, 46, 79 and 67%, respectively, and larger tumors (lung tumors with a diameter of 1-2 or >2 mm) were absent in the MI + IL and MI + rapamycin groups. These results clearly indicated that MI + IL and MI + rapamycin are more effective than MI alone in inhibiting the formation and growth of lung tumors. Assessment of the immunomodulatory effects of the drugs showed that whereas MI + rapamycin and MI + IL increased the infiltration of lung tumors by CD4+ and CD8+ T cells, MI + rapamycin reduced the expression of the immune checkpoint protein programmed-death ligand-1 (PD-L1). Moreover, all treatments, except IL, increased apoptosis, whereas cell proliferation was markedly suppressed in all treated groups. In summary, these results suggest that IL and rapamycin could enhance the efficacy of MI in lung cancer chemoprevention trials.

Non-Acid Fluid Exposure and Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) accounts for the large majority of esophageal cancer cases worldwide. In this review, we examine the potential role of non-acidic fluid (NAF) exposure in ESCC carcinogenesis. Esophageal NAF consists of a mixture of salivary, esophageal, gastric, and duodenal fluids, containing inflammatory constituents such as digestive enzymes and bile acids that induce DNA damage, as well as known carcinogens such as acetaldehyde and N-nitrosamines. Exposure to NAF can occur in the setting of increased non-acid reflux, decreased gastric acidity, and decreased esophageal fluid clearance. Non-acid reflux has been associated with ESCC in small observational studies, and in animal models bile reflux can promote the development of ESCC. Associations have been found between increased ESCC risk and atrophic gastritis, a history of partial gastrectomy, and proton pump inhibitor use, all of which raise the pH of refluxate. Additionally, a minimally or non-acidic gastric environment contains an altered microbiome that can increase the production of acetaldehyde and N-nitrosamines. Esophageal motility disorders such as achalasia and opioid-induced esophageal dysfunction result in increased stasis and exposure to these potentially proinflammatory constituents of NAF. NAF may promote the development of ESCC via multiple mechanisms and is an understudied area of research.

Patterns of Carbon-Bound Exogenous Compounds in Patients with Lung Cancer and Association with Disease Pathophysiology.

Asymptomatic anthracosis is the accumulation of black carbon particles in adult human lungs. It is a common occurrence, but the pathophysiologic significance of anthracosis is debatable. Using in situ high mass resolution matrix-assisted laser desorption/ionization (MALDI) fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry imaging analysis, we discovered noxious carbon-bound exogenous compounds, such as polycyclic aromatic hydrocarbons (PAH), tobacco-specific nitrosamines, or aromatic amines, in a series of 330 patients with lung cancer in highly variable and unique patterns. The characteristic nature of carbon-bound exogenous compounds had a strong association with patient outcome, tumor progression, the tumor immune microenvironment, programmed death-ligand 1 (PD-L1) expression, and DNA damage. Spatial correlation network analyses revealed substantial differences in the metabolome of tumor cells compared with tumor stroma depending on carbon-bound exogenous compounds. Overall, the bioactive pool of exogenous compounds is associated with several changes in lung cancer pathophysiology and correlates with patient outcome. Given the high prevalence of anthracosis in the lungs of adult humans, future work should investigate the role of carbon-bound exogenous compounds in lung carcinogenesis and lung cancer therapy. SIGNIFICANCE: This study identifies a bioactive pool of carbon-bound exogenous compounds in patient tissues associated with several tumor biological features, contributing to an improved understanding of drivers of lung cancer pathophysiology.

Telmisartan (and/or nitrosamine) - induced occult melanoma: first reported case in world literature.

Introduction: The known connections between the terms 'sartans' and 'melanoma' has grown recently in the clinical field, suggesting that the relationship between these concepts is very likely to be significant, rather than hypothetical or unfeasible. This is because: 1) the presence of angiotensin receptors in melanoma tissue, melanocytes and skin is a known fact; 2) the influence of sartans on the processes of melanogenesis has already been presented in recent published scientific papers; 3) key in vitro studies have shown that angiotensin receptor blockers (sartans) could potentiate carcinogenesis in the direction of melanoma and metastases; and 4) clinical examples of the occurrence of melanoma after starting therapy with sartans have become numerous and difficult to ignore.Areas covered: We report the first case of occult melanoma in an 87-year-old Bulgarian patient, this manifested in the form of a solitary metastasis on the left arm, which occurred after long-term therapy with telmisartan.Expert opinion: The fact that nitrosamines have a proven carcinogenic effect and are the cause of heterogeneous neoplasms shows that they have the potential to be possible melanoma triggers. The multifactorial pathogenesis of melanoma could certainly be clarified after the 'crystallization' of this currently serious issue.

Mitotic Spindle Apparatus Abnormalities in Chronic Obstructive Pulmonary Disease Cells: A Potential Pathway to Lung Cancer.

Chronic obstructive pulmonary disease (COPD) is a long-term lung disease characterized by irreversible lung damage resulting in airflow limitation, abnormal permanent air-space enlargement, and emphysema. Cigarette smoking is the major cause of COPD with 15% to 30% of smokers developing either disease. About 50% to 80% of patients with lung cancer have preexisting COPD and smokers who have COPD are at an increased risk for developing lung cancer. Therefore, COPD is considered an independent risk for lung cancer, even after adjusting for smoking. A crucial early event in carcinogenesis is the induction of the genomic instability through alterations in the mitotic spindle apparatus. To date, the underlying mechanism by which COPD contributes to lung cancer risk is unclear. We hypothesized that tobacco smoke carcinogens induce mitotic spindle apparatus abnormalities and alter expression of crucial genes leading to increased genomic instability and ultimately tumorigenesis. To test our hypothesis, we assessed the genotoxic effects of a potent tobacco-smoke carcinogen [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, (NNK)] on bronchial epithelial cells from patients with COPD and normal bronchial epithelial cells and identified genes associated with mitotic spindle defects and chromosome missegregation that also overlap with lung cancer. Our results indicate that exposure to NNK leads to a significantly altered spindle orientation, centrosome amplification, and chromosome misalignment in COPD cells as compared with normal epithelial cells. In addition, we identified several genes (such as AURKA, AURKB, and MAD2L2) that were upregulated and overlap with lung cancer suggesting a potential common pathway in the transition from COPD to lung cancer.

The Impact of One-week Dietary Supplementation with Kava on Biomarkers of Tobacco Use and Nitrosamine-based Carcinogenesis Risk among Active Smokers.

Tobacco smoking is the primary risk factor for lung cancer, driven by the addictive nature of nicotine and the indisputable carcinogenicity of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) as well as other compounds. The integration of lung cancer chemoprevention with smoking cessation is one potential approach to reduce this risk and mitigate lung cancer mortality. Experimental data from our group suggest that kava, commonly consumed in the South Pacific Islands as a beverage to promote relaxation, may reduce lung cancer risk by enhancing NNK detoxification and reducing NNK-derived DNA damage. Building upon these observations, we conducted a pilot clinical trial to evaluate the effects of a 7-day course of kava on NNK metabolism in active smokers. The primary objective was to compare urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL plus its glucuronides, major metabolites of NNK) before and after kava administration as an indicator of NNK detoxification. Secondary objectives included determining kava's safety, its effects on DNA damage, tobacco use, and cortisol (a biomarker of stress). Kava increased urinary excretion of total NNAL and reduced urinary 3-methyladenine in participants, suggestive of its ability to reduce the carcinogenicity of NNK. Kava also reduced urinary total nicotine equivalents, indicative of its potential to facilitate tobacco cessation. Plasma cortisol and urinary total cortisol equivalents were reduced upon kava use, which may contribute to reductions in tobacco use. These results demonstrate the potential of kava intake to reduce lung cancer risk among smokers.

Lifetime cumulative exposure to rubber dust, fumes and N-nitrosamines and non-cancer mortality: a 49-year follow-up of UK rubber factory workers.

OBJECTIVES: To examine associations between occupational exposures to rubber dust, rubber fumes and N-nitrosamines and non-cancer mortality. METHODS: A cohort of 36 441 males aged 35+ years employed in British rubber factories was followed-up to 2015 (94% deceased). Competing risk survival analysis was used to assess risks of dying from non-cancer diseases (respiratory, urinary, cerebrovascular, circulatory and digestive diseases). Occupational exposures to rubber dust, rubber fumes, N-nitrosamines were derived based on a population-specific quantitative job-exposure matrix which in-turn was based on measurements in the EU-EXASRUB database. RESULTS: Exposure-response associations of increased risk with increasing exposure were found for N-nitrosomorpholine with mortality from circulatory diseases (subdistribution hazard ratio (SHR) 1.17; 95% CI 1.12 to 1.23), ischaemic heart disease (IHD) (SHR 1.19; 95% CI 1.13 to 1.26), cerebrovascular disease (SHR 1.19; 95% CI 1.07 to 1.32) and exposures to N-nitrosodimethylamine with respiratory disease mortality (SHR 1.41; 95% CI 1.30 to 1.53). Increased risks for mortality from circulatory disease, IHD and digestive diseases were found with higher levels of exposures to rubber dust, rubber fumes and N-nitrosamines sum, without an exposure-dependent manner. No associations were observed between rubber dust, rubber fumes and N-nitrosamines exposures with mortality from asthma, urinary disease, bronchitis, emphysema, liver disease and some digestive diseases. CONCLUSIONS: In a cohort of rubber factory workers with 49 years of follow-up, increased risk for mortality from circulatory, cerebrovascular, respiratory and digestive diseases were found to be associated with cumulative occupational exposures to specific agents.

Consumption of drinking water N-Nitrosamines mixture alters gut microbiome and increases the obesity risk in young male rats.

N-nitrosamines (NAs) are an emerging group of disinfection by-products that occur as a mixture in drinking water. Although the potency of the individual NA components in drinking water is negligible, their combined effect is rarely reported. We tested whether multicomponent NAs mixtures at environmentally relevant levels would produce significant effects when each component was combined at extremely low concentrations i.e. a million times lower than its No Observed Effect Concentration (NOEC). Mixture L (the maximum values detected in drinking water) or mixture M (one order of magnitude higher than detected) were fed to male and female Sprague-Dawley (SD) rats since PND 28 for seven days. We found that the body weight gains and the triglyceride (TG) levels increased significantly in mixture M treated male rats. Correspondingly, an obesogenic microbiota profile was obtained in the mixture M treated young male rat: Firmicutes/Bacteroidetes and the obesity-related taxa including Alistipes, Ruminococcus were enriched. Collectively, this is the first in vivo demonstration of NAs mixtures at environmentally relevant levels. Despite the complicated relationship between gut microbiota and obesity, our study has demonstrated that changes in gut microbiota may contribute to the development of obesity after the exposure. Our results highlight that changes in gut microbiota could be a risk factor for obesity, which emphasizes the need to include gut microbiota in the traditional mammalian risk assessment.

Microbial metabolites of proanthocyanidins reduce chemical carcinogen-induced DNA damage in human lung epithelial and fetal hepatic cells in vitro.

Seven selected microbial metabolites of proanthocyanidins (MMP), 3-phenylpropionic, 4-hydroxyphenyl acetic, 3-(4-hydroxyphenyl) propionic, p-coumaric, benzoic acid, pyrogallol (PG), and pyrocatechol (PC) were evaluated for their ability to reduce chemical carcinogen-induced toxicity in human lung epithelial cells (BEAS-2B) and human fetal hepatic cells (WRL-68). Cells pre-treated with MMP were exposed to a known chemical carcinogen, 4-[(acetoxymethyl) nitrosamino]-1-(3-pyridyl)-1-butanone (NNKOAc) to assess MMP-mediated cytoprotection and reduction of DNA damage. PG in BEAS-2B and PC in WRL-68 cells mitigated the NNKOAc-induced cytotoxicity. Pre-incubation of PG depicted significant protection against NNKOAc-induced DNA damage in BEAS-2B cells. PC in WRL-68 cells showed similar activity. To understand the mechanisms of PG- and PC-mediated DNA damage reduction, the effect on DNA damage response (DDR) proteins, cellular reactive oxygen species (ROS), total antioxidant capacity (TAC), glutathione peroxidase (GPx), and caspase activity were studied. PG and PC alter the DDR and may promote ATR-Chk1 and ATM-Chk2 pathways, respectively. Cellular oxidative stress induced by NNKOAc was mitigated by PG and PC through enhanced GPx expression and TAC. PG and PC suppressed the activation of the extrinsic apoptotic pathway (caspase 3 and 8) provoked by NNKOAc. MMP are beneficial in chemoprevention by reducing cellular DNA damage.

Job-exposure matrix for historical exposures to rubber dust, rubber fumes and n-Nitrosamines in the British rubber industry.

OBJECTIVES: To develop a quantitative historical job-exposure matrix (JEM) for rubber dust, rubber fumes and n-Nitrosamines in the British rubber industry for 1915-2002 to estimate lifetime cumulative exposure (LCE) for a cohort of workers with 49 years follow-up. METHODS: Data from the EU-EXASRUB database-rubber dust (n=4157), rubber fumes (n=3803) and n-Nitrosamines (n=10 115) collected between 1977 and 2002-were modelled using linear mixed-effects models. Sample year, stationary/personal measurement, industry sector and measurement source were included as fixed explanatory variables and factory as random intercept. Model estimates and extrapolations were used to construct a JEM covering all departments in both sectors of the rubber manufacturing industries for the years 1915-2002. JEM-estimates were linked to all cohort members to calculate LCE. Sensitivity analyses related to assumptions about extrapolation of time trends were also conducted. RESULTS: Changes in rubber dust exposures ranged from -6.3 %/year (crude materials/mixing) to -1.0 %/year (curing) and -6.5 %/year (crude materials/mixing) to +0.5 %/year (finishing, assembly and miscellaneous) for rubber fumes. Declines in n-Nitrosamines ranged from -17.9 %/year (curing) to -1.3 %/year (crude materials and mixing). Mean LCEs were 61 mg/m3-years (rubber dust), 15.6 mg/ m3-years (rubber fumes), 2483.2 µg/m3-years (n-Nitrosamines sum score), 18.6 µg/m3-years (N-nitrosodimethylamine) and 15.0 µg/m3-years (N-itrosomorpholine). CONCLUSIONS: All exposures declined over time. Greatest declines in rubber dust and fumes were found in crude materials and mixing and for n-Nitrosamines in curing/vulcanising and preprocessing. This JEM and estimated LCEs will allow for evaluation of exposure-specific excess cancer risks in the British rubber industry.

Lifetime exposure to rubber dusts, fumes and N-nitrosamines and cancer mortality in a cohort of British rubber workers with 49 years follow-up.

OBJECTIVES: To quantitatively evaluate exposure-response associations between occupational exposures to rubber dust, fumes and N-nitrosamines and cancer mortality in the UK rubber industry. METHODS: Competing risk survival analyses were used to examine cancer mortality risk in a cohort of 36 441 males aged 35+ years employed in the British rubber industry in 1967, followed up to 2015 (94% mortality). Exposure measurements are based on a population-specific quantitative job-exposure matrix for rubber dust, rubber fumes and N-nitrosamines from the EU-EXASRUB project. RESULTS: Exposure (lifetime cumulative (LCE))-response associations were found for N-nitrosomorphiline and all cancers (subdistribution HR (SHR) 1.48, 95% CI 1.39 to 1.57) and cancers of the bladder, stomach, multiple myeloma, oesophagus, prostate and pancreas, as well as for N-nitrosodimethylamine and all cancers (SHR 2.08, 95% CI 1.96 to 2.21) and cancers of the bladder, stomach, leukaemia, multiple myeloma, prostate and liver. LCE to the N-nitrosamines sum were associated with increased risks from all cancers (SHR 1.89, 95% CI 1.78 to 2.01) and cancers of the lung, non-Hodgkin's lymphoma and brain. LCE to rubber dust and fumes are associated with increased mortality from all cancers (rubber dust SHR 1.67, 95% CI 1.58 to 1.78; rubber fumes SHR 1.91, 95% CI 1.80 to 2.03) and cancers of the bladder, lung, stomach, leukaemia, multiple myeloma, non-Hodgkin's lymphoma, oesophagus, prostate, pancreas and liver. CONCLUSIONS: Consistent with previous studies, N-nitrosamines exposures are associated with mortality from cancers of the bladder, lung, stomach, leukaemia, multiple myeloma, oesophagus, prostate, pancreas and liver. The long follow-up with nearly complete mortality enabled estimations of lifetime cancer mortality risk from occupational exposures in the rubber industry.

Fruit and vegetable consumption, cigarette smoke, and leukocyte mitochondrial DNA copy number.

Background: Mitochondrial dysfunction is an important component of the aging process and has been implicated in the development of many human diseases. Mitochondrial DNA copy number (mtDNAcn), an indirect biomarker of mitochondrial function, is sensitive to oxidative damage. Few population-based studies have investigated the impact of fruit and vegetable consumption and cigarette smoke (2 major sources of exogenous antioxidants and oxidants) on leukocyte mtDNAcn. Objectives: We investigated the association between fruit and vegetable consumption, cigarette smoke, and leukocyte mtDNAcn based on data from the Nurses' Health Study (NHS). Methods: Data from 2769 disease-free women in the NHS were used to examine the cross-sectional associations between dietary sources of antioxidants, cigarette smoke, and leukocyte mtDNAcn. In vitro cell-based experiments were conducted to support the findings from the population-based study. Results: In the multivariable-adjusted model, both whole-fruit consumption and intake of flavanones (a group of antioxidants abundant in fruit) were positively associated with leukocyte mtDNAcn (P-trend = 0.005 and 0.02, respectively), whereas pack-years of smoking and smoking duration were inversely associated with leukocyte mtDNAcn (P-trend = 0.01 and 0.007, respectively). These findings are supported by in vitro cell-based experiments showing that the administration of naringin, a major flavanone in fruit, led to a substantial increase in mtDNAcn in human leukocytes, whereas exposure to nicotine-derived nitrosamine ketone, a key carcinogenic ingredient of cigarette smoke, resulted in a significant decrease in mtDNAcn of cells (all P < 0.05). Further in vitro studies showed that alterations in leukocyte mtDNAcn were functionally linked to the modulation of mitochondrial biogenesis and function. Conclusions: Fruit consumption and intake of dietary flavanones were associated with increased leukocyte mtDNAcn, whereas cigarette smoking was associated with decreased leukocyte mtDNAcn, which is a promising biomarker for oxidative stress-related health outcomes.

Evaluation of cytogenic damage in the form of micronuclei in oral exfoliated buccal cells in tobacco users.

BACKGROUND: Variety of substances such as tobacco, UV radiation, infrared rays, X-radiations, and chemicals on oral induction results in chromosomal aberrations and production of micronucleus (MN). Among them, tobacco-specific nitrosamines are potent mutagenic agents causing oral cancer. OBJECTIVE: The objective of the study is to compare the genotoxicity in buccal mucosal cells, i.e. the MN count of all groups and to find the incidence of micronucleated cells (MNCs) in accordance to duration and frequency of tobacco usage and timing of contact of tobacco in the oral mucosa. MATERIALS AND METHODS: Individuals without any oral diseases were divided into 3 groups having 25 in each group: smoking, chewing, and control. Smears were made from buccal exfoliated cells and stained with DNA-specific Feulgen stain. Frequency on MNC per 500 cells was assessed with one-way ANOVA and Tukey HSD multiple comparisons test and mean rank with Kruskal-Wallis test. RESULTS: The mean micronucleus MN revealed that chewers had 8.00, smokers had 7.20 and controls had 0.4. The ANOVA test for mean frequency of micronucleated cell MNC revealed High significance (<0.001) for between groups comparison. The mean rank by Kruskal Wallis test revealed the MNC increases as the duration and frequency of habit increases. An increase in MNC in accordance to time of contact with buccal mucosa increases as the duration and time increases. CONCLUSION: Estimation of MN serve as an indicator of genetic damage and points that tobacco in chewing form induce genotoxic effect. This is studied in an easily accessible tissue- buccal mucosa in a non invasive manner.