Influence of smoking and smoking cessation on levels of urinary 11-dehydro thromboxane B2

Biomarkers of Exposure and Potential Harm in Two Weeks of Smoking Abstinence: Changes in Biomarkers of Platelet Function, Oxidative Stress, and Inflammation

: Chronic cigarette smoking is a major risk factor for many serious diseases. While complete cessation of smoking is the best option to reduce harm from smoking, adverse impacts of smoking on health could persist for several years after cessation. Therefore, Biomarkers of Potential Harm (BoPH) are useful in interim evaluations of the beneficial effects of smoking cessation or switching to potentially lower-risk tobacco products. A 14-day smoking abstinence study was conducted under clinical confinement conditions and enrolled 70 subjects into younger (24–34 years, n = 33) and older (35–60 years, n = 37) age cohorts. Biomarkers of Exposure (BoE), which indicate exposure to nicotine and other toxicants, were measured at baseline, 7 and 14 days. Several BoPH including previously identified eicosanoids (leukotriene 4 (LTE4) and 2,3-dinor thromboxane 2 (2,3-d-TXB2) and others were evaluated. Significant declines in BoE, LTE4, 2,3-d-TXB2, neutrophils, WBC and select RBC, and arterial blood gas parameters were observed in both age cohorts at Days 7 and 14 compared to baseline, while other BoPH (e.g., FeNO) showed age-related effects. Rapid and reproducible reductions in LTE4, 2,3-d-TXB2 WBC, and neutrophil counts were consistently detected following smoking abstinence, indicating the value of these markers as useful BoPH.

Commonalities in Metabolic Reprogramming between Tobacco Use and Oral Cancer

Tobacco use is a major public health concern and is linked to myriad diseases, including cancer. The link between tobacco use and oral cancer, specifically, is very strong, making tobacco use one of the primary risk factors for oral cancer. While this association is well known, the underlying biochemical changes that result from tobacco use, and how this links to metabolic phenotypes of oral cancer, is not well understood. To address this knowledge gap, a combination of literature reviews and metabolomics studies were performed to identify commonalities in metabolic perturbations between tobacco use and oral cancers. Metabolomics analysis was performed on pooled reference urine from smokers and non-smokers, healthy and malignant oral tissues, and cultured oral cells with or without treatment of the well-known tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Alterations in amino acid metabolism, carbohydrates/oxidative phosphorylation, fatty acid oxidation, nucleotide metabolism, steroid metabolism, and vitamin metabolism were found to be shared between tobacco use and oral cancer. These results support the conclusion that tobacco use metabolically reprograms oral cells to support malignant transformation through these pathways. These metabolic reprogramming events may be potential targets to prevent or treat oral cancers that arise from tobacco use.

Real-World Evidence of Differences in Biomarkers of Exposure to Select Harmful and Potentially Harmful Constituents and Biomarkers of Potential Harm Between Adult E-Vapor Users and Adult Cigarette Smokers

INTRODUCTION

Real-world evidence regarding likely long-term health effects of e-vapor products (EVP) under actual use conditions relative to cigarette smoking is not well studied.

METHODS

In this cross-sectional, observational study, biomarkers of exposure (BOE) to select harmful and potentially harmful constituents and biomarkers of potential harm (BOPH) relevant to smoking-related diseases were measured in exclusive adult EVP users (AEVP, n = 144) and exclusive adult cigarette smokers (AS, n = 73). AEVP used their own brand of EVP for 6+ months following 10+ years of cigarette smoking and AS smoked own brand of cigarettes for 10+ years. Subject recruitment and informed consent were obtained online and urine/blood samples were collected at local clinical laboratories, representing a new paradigm for collecting real-world evidence.

RESULTS

The levels of total NNAL (NNK metabolite), 3-hydroxypropyl mercapturic acid (acrolein metabolite), and carboxyhemoglobin (carbon monoxide measure) were 46% to 86% lower in AEVP compared with AS (p ≤ .0001) as was nicotine equivalents (nicotine and its five metabolites; 36%, p < .01). The levels of some BOPH were significantly lower in AEVP compared with AS for 11-dehydrothromboxane-B2 (29%, p = .04; platelet activation), 8-epi-prostaglandin F2α (23%, p = .02; oxidative stress) and soluble intercellular adhesion molecule-1 (16%, p = .02; endothelial function).

CONCLUSIONS

This study demonstrates the feasibility of a new approach for collecting real-world evidence. Substantially lower levels of BOEs (NNK, nicotine, acrolein, carbon monoxide) and favorable differences in BOPHs (platelet activation, oxidative stress, endothelial function) suggest EVP users may have lower health risks than cigarette smokers.

IMPLICATIONS

Cigarette smoking causes serious diseases. Switching from a combustible tobacco product to a noncombustible product is a potential harm reduction pathway for adult smokers unable or unwilling to quit. Real-world evidence regarding the relative risk of EVP use compared with cigarettes is not well established. This study provides data specific to BOE to tobacco smoke constituents and biomarkers of potential harm collected under actual use conditions in a real-world setting. The totality of evidence suggests that exclusive EVP use may present lower health risk compared with smoking cigarettes.

Statistical analysis plan for "A randomised, controlled study to evaluate the effects of switching from cigarette smoking to using a tobacco heating product on health effect indicators in healthy subjects"

Tobacco harm reduction strategies aim to substitute smoking with potentially reduced risk products (PRRPs) such as e-cigarettes and tobacco-heating products (THPs). The health benefits of switching from smoking to PRRPs is unknown. A randomised controlled trial is being conducted to increase understanding of the health effects of switching from smoking to a THP in a 12-month long ambulatory study (ISRCTN81075760). Here we describe the study endpoints and the statistical analysis plan. Endpoints are divided into biomarkers of exposure (BoE) to tobacco smoke constituents and health effect indicators related to risk of lung cancer, cardiovascular and obstructive lung disease. These have been selected on the basis of extensive literature evidence. Three primary endpoints, augmentation index (risk factor for cardiovascular disease), total NNAL (linked to lung cancer) and 8-Epi-PGF2α type III (indicator of oxidative stress linked to various diseases), and multiple secondary endpoints will be analysed at 90, 180, and 360 days. Changes from baseline will be compared between study arms by specific contrasts in mixed models. Study wise multiple comparisons adjustments will be performed to account for multiplicity of timepoints and comparisons within timepoints. Generalisability of outcomes will be tested by a sensitivity analysis adjusting for age and gender. Importantly, an ancillary analysis will be performed to assess product compliance during the study based on plasma levels of CEVal, a surrogate marker for acrylonitrile exposure. The rationale underlying the selection of BoEs and health effect indicators, coupled with the statistical analysis plan will be central to understanding the potential health effects of replacing smoking with THP use for one year.