Search Results (215)

Nicotine is the main psychoactive component of tobacco and is considered to be the main substance responsible for the development of tobacco addiction. The main enzyme responsible for nicotine metabolism, CYP2A6, catalyzes the conversion of nicotine to cotinine and the subsequent metabolism of cotinine to trans-3′-hydroxycotinine. CYP2A6 activity is known to be modulated by various compounds, such as quercetin. This repeated-measures study examined the effects of short-term quercetin supplementation on urinary nicotine metabolism biomarkers in adult users of conventional and alternative nicotine products. Seventy-two participants completed a two-week study protocol involving first-morning urine collection at four time points: baseline, immediately after three days of quercetin supplementation (500 mg/day), seven days after supplementation, and ten days after supplementation. Urinary nicotine, cotinine, and trans-3′-hydroxycotinine concentrations were measured, and the nicotine metabolite ratio was calculated as trans-3′-hydroxycotinine/cotinine. Repeated-measures analysis of variance was used to evaluate biomarker changes over time according to sex, nicotine product type, and self-reported nicotine consumption intensity. Quercetin supplementation did not consistently alter nicotine metabolism biomarkers, while a descriptive increase in median urinary nicotine concentration after supplementation was observed in participants reporting lower daily nicotine consumption compared with other groups. These findings suggest that further studies are warranted to better clarify the effects of quercetin on nicotine metabolism across different levels of nicotine exposure. Full article

Chronic oxidative stress is a molecular hallmark of cardiovascular–kidney–metabolic (CKM) syndrome, yet its contribution to CKM-associated anemia beyond erythropoietin deficiency and iron restriction is poorly characterized. The serum copper-to-zinc (Cu/Zn) ratio reflects impaired Cu/Zn-SOD1 antioxidant capacity and inflammatory trace-element imbalance, but its relationships with circulating redox biomarkers and its hematological relevance in CKM syndrome has never been explored in a community-dwelling cohort of older adults. We analyzed 2391 NHANES 2011–2016 participants ≥ 50 years of age with CKM stage I-IV. To explore whether the serum Cu/Zn ratio was associated with oxidative stress and immunomodulatory biomarkers as well as with the odds of anemia, we used survey-weighted Spearman correlations, linear regression (outcome: hemoglobin), and logistic regression (outcome: anemia); multivariate models were adjusted for a panel of antioxidant or immunomodulatory biomarkers (selenium, vitamin D), pro-oxidant biomarkers (lead, cadmium, cotinine, uric acid), red cell distribution width (RDW) as a composite biomarker of erythrocyte stress, neutrophil-to-lymphocyte ratio (NLR), CKM stage, and comorbidities. The molecular targets of the nine biomarkers were mapped onto a protein–protein interaction network using the STRING database v12.0 to contextualize regression findings within a systems biology framework. Anemia was present in 205 participants (8.6%). The Cu/Zn ratio was inversely correlated with the antioxidant marker selenium (r = −0.19; p < 0.001) and positively correlated with the pro-oxidant markers RDW (r = +0.21; p < 0.001) and cadmium (r = +0.10; p < 0.001), consistent with its role as a hub within the CKM redox network. In fully adjusted models, a higher Cu/Zn ratio was independently associated with prevalent anemia (OR = 2.94; 95% CI: 1.61–5.37) and lower hemoglobin (β = −0.55 g/dL); among included biomarkers, selenium and cadmium were independently protective (OR = 0.76 per 10 µg/L and 0.23 per µg/dL, respectively), and RDW and uric acid were independently harmful (OR = 2.20 per 1% and 1.33 per mg/dL, respectively). The Cu/Zn ratio correlated with both antioxidant depletion and pro-oxidant accumulation in CKM syndrome and was independently associated with anemia within this oxidative network. Together with selenium, cadmium, RDW, and uric acid, it defines an oxidative stress-driven hematological pathway that may contribute to the development and progression of anemia in patients with CKM syndrome. Full article

Background: Secondhand exposure to heated tobacco products (HTPs) is increasingly common, but its impact on human milk composition is unclear. We investigated whether secondhand exposure to HTP aerosols affects major human milk components and cotinine concentrations in lactating women. Methods: This observational study included 15 lactating women whose household members used HTPs (secondhand HTP exposure group) and 33 lactating women who did not live with any smokers (non-exposed group). Human milk was analyzed for macronutrients, total solids, energy, lactoferrin, secretory immunoglobulin A (sIgA), calcium, inorganic phosphorus, zinc, and cotinine. Cotinine was measured in all women in the secondhand HTP exposure group and in three women in the non-exposed group. Results: Background characteristics did not differ significantly between groups. No significant differences were observed in lipid, protein, total solids, energy, true protein, lactoferrin, calcium, inorganic phosphorus, or zinc. Carbohydrate concentration differed significantly between the non-exposed and secondhand HTP exposure groups (non-exposed vs. secondhand HTP exposure: 8.20 vs. 8.10 g/dL, p = 0.032), although the absolute difference was small. sIgA tended to be higher in the secondhand HTP exposure group (non-exposed vs. secondhand HTP exposure: 1244 vs. 1706 μg/mL, p = 0.072). Cotinine concentrations did not differ significantly between groups; qualitative cotinine tests were negative in all samples. Conclusions: Secondhand exposure to HTPs was not associated with clear differences in major human milk components or cotinine concentrations. However, the findings should be interpreted cautiously because of the small sample size and limited cotinine assessment. Larger studies with objective exposure assessment and infant follow-up are needed. Full article

Background/Objectives: Pregnancy is characterized by profound metabolic and physiological adaptations that influence systemic redox balance. Longitudinal data assessing trimester-specific changes in antioxidant status and oxidative stress markers remain limited. Methods: In this longitudinal study, plasma levels of non-enzymatic antioxidants (vitamins A, C, E, and carotenoids) and oxidative stress markers (malondialdehyde, conjugated dienes, protein carbonyls, and DNA strand breaks) were analyzed in 31 healthy non-smoking pregnant women during the first, second, and third trimester. Environmental tobacco smoke exposure was evaluated using urinary cotinine. Statistical analyses were performed using Friedman repeated-measures tests followed by Dunn’s post hoc comparisons with Benjamini–Hochberg false discovery rate correction. Results: Vitamin A was the only antioxidant that consistently decreased across all trimesters and represented the only antioxidant marker showing a consistent decline. In contrast, α-tocopherol, γ-tocopherol, xanthophylls, and lycopene increased significantly during gestation, whereas vitamin C remained relatively stable. Markers of oxidative damage, including malondialdehyde, conjugated dienes, protein carbonyls, and DNA strand breaks, showed significant trimester-dependent increases. Total antioxidant capacity (FRAP) remained unchanged throughout pregnancy. Conclusions: Physiological pregnancy is characterized by coordinated, marker-specific adaptations in systemic redox balance. Vitamin A was the only antioxidant showing a consistent decline across gestation, whereas several lipid-soluble antioxidants increased and total antioxidant capacity remained stable. These findings indicate that pregnancy is associated with increased oxidative activity accompanied by preservation of systemic antioxidant capacity rather than global antioxidant depletion. Full article

Background: This study was conducted to identify genetic risk variants associated with nicotine addiction in the CHRNA5, HTR2A, DRD4, and CYP2A6 genes among electronic cigarette users who also smoke combustible cigarettes (dual users), and to assess potential genotoxic and cytotoxic damage in the oral mucosal cells of the study population. Methods: We included dual e-cig users (ECIG, n = 70), combustible cigarette smokers (CCU, n = 24), and non-smokers and non-e-cig users (NS, n = 110). Genetic variants in CHRNA5, HTR2A, DRD4, and CYP2A6 were genotyped. Micronucleus analysis was performed on oral mucosal cells to detect cellular abnormalities. Results: The ECIG group demonstrated greater nicotine addiction on the Fagerström Test for Nicotine Dependence (FTND, 5.5 vs. 1, p = 0.023). Salivary cotinine levels were significantly higher in the ECIG group compared to the CCU group (39 vs. 12 ng/mL, p < 0.001). The carriers of the A allele (rs16969968/CHRNA5) had higher FTND scores, carriers of the C allele (rs1800955/DRD4) used electronic cigarettes more frequently each day, and carriers of the T allele (rs4105144/CYP2A6) started using nicotine products at a younger age. The number of micronuclei and cellular abnormalities in the oral mucosa was higher in the ECIG and CCU groups compared to the NS group. Conclusions: Salivary cotinine levels and FTND are higher in dual e-cigarette users than in combustible cigarette users. Dual users exhibit risk alleles in the CHRNA5, DRD4, and CYP2A6 genes, which are associated with traits linked to increased nicotine addiction. Dual e-cigarette use poses comparable genotoxic risks to combustible smoking. Full article

This prospective observational study investigated secondhand smoke (SHS) exposure levels across gestational stages and identified longitudinal associated factors among pregnant women in Darkhan-Uul Province, Mongolia. Participants recruited between October 2019 and September 2020 answered a self-administered questionnaire and provided spot urine samples at each trimester. SHS exposure was assessed via urinary cotinine (UC) levels, and generalized estimating equations were used to identify associated factors. The final sample included 526 participants. UC levels ≥ 5 ng/mL were observed in 40.1%, 32.0%, and 29.0% of participants in the first, second, and third trimesters, respectively. Compared to the first trimester, the risk of SHS exposure was significantly lower in the second (adjusted odds ratio [AOR]: 0.70; 95% confidence interval [CI]: 0.54–0.91) and third trimesters (AOR: 0.59; 95% CI: 0.45–0.77). Additionally, compared to smoke-free households, those permitting smoking in designated areas (AOR: 1.70; 95% CI: 1.28–2.26) or having no restrictions (AOR: 2.54; 95% CI: 1.29–4.96) showed higher odds of exposure. These results highlight the importance of household smoking restrictions and should be disseminated among pregnant women, their families, and healthcare providers to reduce risk of SHS exposure. Full article

Background/Objectives: Cigarette smoking is a major risk factor for periodontitis, but the salivary host-response profile associated with smoking-related periodontal inflammation remains incompletely characterized. This study compared salivary NETosis-related and oxidative-inflammatory biomarkers among current smokers, former smokers, and never-smokers with periodontitis. Methods: This cross-sectional study included 159 systemically healthy adults with periodontitis (53 per group: current smokers, former smokers, never-smokers). Individuals with systemic diseases or concomitant medications that could interfere were excluded. Unstimulated whole saliva was analyzed for NETosis-related biomarkers (MPO-DNA complexes, citrullinated histone H3, neutrophil elastase, cell-free DNA) and oxidative-inflammatory markers (MMP-8, IL-1β, IL-6, TNF-α, 8-OHdG, total antioxidant capacity). Results: Salivary MPO-DNA complexes differed significantly among groups (current smokers 33.52 ± 9.96, former smokers 26.90 ± 8.38, never-smokers 19.20 ± 7.50 ng/mL; p < 0.001, η² = 0.317). The composite NETosis score (η² = 0.702) and oxidative-inflammatory score (η² = 0.718) showed the same graded pattern. Biochemical verification confirmed clear group separation (salivary cotinine: current smokers 312.3 ± 77.0, former smokers 9.7 ± 5.1, never-smokers 3.2 ± 1.4 ng/mL). Smoking exposure was positively correlated with biomarker levels and the severity of periodontal disease. Smoking status remained independently associated with MPO-DNA complexes and the NETosis score after covariate adjustment. Conclusions: Current smoking was associated with an enhanced salivary NETosis-related and oxidative-inflammatory phenotype. Former smokers displayed an intermediate profile. Salivary MPO-DNA complexes and composite biomarker scores warrant further investigation as candidate non-invasive indicators of smoking-associated periodontal inflammatory burden, pending diagnostic performance analyses and prospective validation. Full article

Cigarette smoke contains a high concentration of carcinogenic substances to which smokers are regularly exposed. Passive smoking is seriously harmful to the health of non-smoking humans and animals. Domestic cats are particularly vulnerable because of their constant grooming activity, which can promote oral ingestion of smoke-derived residues. Cotinine, a nicotine metabolite, is a reliable biomarker for tobacco exposure. Considering these observations, our study aimed to (1) characterize cytological alterations in oral mucosal epithelial cells by conventional morphology and automated digital cytomorphometry; (2) quantify urinary cotinine concentration and investigate its possible correlation with oral epithelial cytological alterations. To this aim, oral smears were collected from 30 cats divided into two groups (20 exposed; 10 non-exposed). Smears were stained with May–Grünwald–Giemsa and Papanicolaou to assess inflammation and dysplasia; digital cytomorphometric analysis was used to quantify the nucleus-to-cytoplasm (N/C) ratio. Urinary cotinine was measured by ELISA. Our results showed that exposed cats had significantly higher urinary cotinine levels and higher N/C ratios (p < 0.01) than non-exposed controls, along with mild-to-severe inflammation and dysplastic-like epithelial alterations. These findings support urinary cotinine as a valid biomarker of household tobacco smoke exposure in domestic cats and suggest that such exposure may be correlated with early cytological and cytomorphometric changes in the oral mucosa. Further studies are needed to better investigate the relationship between exposure duration and cytological, cytomorphometric, and molecular alterations. Full article

Background/Objectives: Oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs) remain major clinical challenges due to late diagnosis and limited prognostic markers. This study evaluated salivary interleukin-6 (IL-6) and cotinine as potential biomarkers for oral epithelial transformation and exposure to risk factors. Methods: From 267 individuals with histopathologically confirmed OPMDs or OSCC, 47 patients met the inclusion criteria and were enrolled (18 OPMDs, 29 OSCC). A control group comprised 40 individuals without oral mucosal pathology. Unstimulated saliva samples were collected and analyzed for IL-6 and cotinine concentrations. Biomarker levels were compared among groups and evaluated in relation to smoking exposure, alcohol use, and clinicopathological parameters. Results: Salivary IL-6 and cotinine levels differed significantly among groups (p < 0.05), with the highest concentrations observed in OSCC patients, intermediate levels in OPMDs, and the lowest levels in controls. Cotinine levels were significantly higher in smokers and individuals with greater tobacco exposure in both study groups, whereas IL-6 concentrations were not significantly associated with smoking or alcohol consumption. No correlation between IL-6 and cotinine was found in OPMDs or OSCC; however, a moderate negative correlation was observed in controls. Conclusions: Salivary IL-6 and cotinine demonstrate potential as complementary, non-invasive biomarkers for assessing oral epithelial transformation and tobacco exposure. Their combined evaluation may support risk stratification and early detection in patients with OPMDs. Full article

Maternal Smoking During Pregnancy (MSDP) remains a major source of fetal toxicant exposure. We applied adductomics to profile reactive adducts at the human serum albumin cysteine-34 (HSA-Cys³⁴) locus, which integrates longer-term exposures. HSA-Cys³⁴ adducts formed by acrylonitrile and ethylene oxide, two tobacco-related toxicants previously linked to smoking in adults, were quantified and compared with cotinine and MSDP status. Their relationships with other reactive adducts were also examined. Neonatal dried blood spots (DBS) from 110 children were analyzed. Cotinine and 55 Cys³⁴ adducts were measured by Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS). Associations were evaluated using linear regression, chi-square tests, and principal component analysis. Eighteen adducts differed significantly by MSDP status after Bonferroni correction (p ≤ 9.1 × 10⁻⁴). S-acrylonitrile was markedly elevated in exposed newborns, including those whose mothers reported smoking cessation after early pregnancy (p < 0.001). S-acrylonitrile correlated with 31 adducts related to oxidative stress and thiol metabolism, whereas cotinine correlated with eight. S-ethylene oxide, though detectable in DBS, showed no consistent association with MSDP. Adductomics analysis of newborn DBS sensitively captures molecular signatures of prenatal tobacco exposure and related oxidative stress. Acrylonitrile adducts appear to better reflect cumulative MSDP exposure than cotinine, highlighting the utility of adductomics for improved exposure assessment and mechanistic insight. Full article

Background/Objectives: Heated tobacco products (HTPs) are a gateway to nicotine addiction for non-smokers, especially young people. The short- and long-term health effects of using heated tobacco products are not yet fully understood. The study aimed to assess the effect of heated tobacco use on blood pressure and heart rate in young, healthy individuals aged 18–30. The study also assessed exposure to tobacco smoke by measuring salivary cotinine concentration. Methods: The case–control study was conducted in 2022–2025 among 200 healthy individuals aged 18–30 years: 70 I-Quit-Ordinary-Smoking users (IQOS), 65 daily traditional cigarette smokers (DS), and 65 non-smokers (NS). The research tool was a questionnaire containing information on the use of tobacco products. The participants completed a questionnaire and then underwent blood pressure measurements, anthropometric measurements, and saliva collection for cotinine levels. Results: The average age of initiation of IQOS use was 18.5 years, and smoking had continued for an average of 2.3 years. The average age of initiation of smoking traditional cigarettes was 16.3 years, and smoking had continued for 4.4 years. There were no statistically significant differences in median values between systolic blood pressure (SBP) and diastolic blood pressure (DBP) between the IQOS, DS, and NS groups (p > 0.05). High SBP values ≥ 140 mm Hg were observed in 10% of the IQOS users, 18.5% of the daily smokers of conventional cigarettes, and 12.3% of the non-smokers. High DBP values ≥ 90 mm Hg were observed in 11.4% of IQOS, 7.7% of DS, and 7.7% of NS. The cigarette smokers demonstrated significantly higher median cotinine levels compared to the IQOS users and non-smokers: 153.7 vs. 64.3 vs. 0.5 ng/mL (p < 0.01). Salivary cotinine levels were positively correlated (ρ = 0.38; p < 0.01) with the daily number of heated tobacco sticks among IQOS users (weak correlation), as well as among DS (ρ = 0.42; p < 0.01) with a higher daily number of cigarettes (moderate correlation). Conclusions: Long-term studies are needed to determine the health effects of heated tobacco products among young people in Poland. Furthermore, the potential impact of HTP aerosols on passive smokers should be examined. Further studies should consider the use of salivary cotinine as a biomarker. Full article

Nicotine exposure from e-cigarette use remains a growing public health concern, necessitating reliable biomarkers and analytical approaches for long-term exposure assessment. This study aimed to investigate the feasibility of detecting and classifying cotinine, the primary metabolite of nicotine, in fingernails of e-cigarette users using Fourier transform infrared (FTIR) spectroscopy coupled with chemometric analysis. Fingernail samples were collected and extracted from 30 e-cigarette users and 30 non-smokers. Infrared spectra were acquired in attenuated total reflectance mode and analysed using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) for classification and prediction. Distinct spectral features associated with cotinine were observed in smoker samples, particularly an absorption band near 1277 cm⁻¹ corresponding to C–N stretching vibrations. Quantitative analysis revealed significantly higher cotinine concentrations in smokers compared with non-smokers (p < 0.05, Mann–Whitney U test). Chemometric modelling achieved complete discrimination between groups, with the PLS-DA model demonstrating excellent predictive performance and an area under the receiver operating characteristic (ROC) curve of 1.0. These findings indicate that FTIR spectroscopy combined with chemometric tools provides a rapid and effective approach for cotinine detection in fingernails, supporting its potential application in nicotine exposure assessment. Full article

Tobacco smoke exposure not only increases the risks of lung cancer and cardiovascular disease, but can be a stressor contributing to mental illness. It is important to clarify the relationship between chronic tobacco smoke exposure and mental stress from the perspective of disease prevention. We developed a simple and highly sensitive method for simultaneously analyzing nine biomarkers: nicotine and cotinine (tobacco smoke exposure markers); cortisol, testosterone, and dehydroepiandrosterone (stress-related markers); and serotonin, melatonin, dopamine, and oxytocin (relaxation-related markers). Biomarkers were extracted and concentrated by in-tube solid-phase microextraction with a Supel-Q PLOT capillary, followed by separation and detection within 7 min using liquid chromatography–tandem mass spectrometry on a Discovery HS F5 column. Calibration curves using stable isotope-labeled internal standards showed good linearity (0.005–100 ng mL⁻¹) with detection limits of 0.09–13.5 pg mL⁻¹. Intra-day and inter-day precision had relative standard deviations below 7.2% and 15.5% (n = 6), respectively, with recovery rates of 84.0–108.8%. The automated method requires only ultrafiltration of hair methanol extract, enabling non-invasive pg-level analysis using just a few milligrams of hair. Hair analysis reflects an association between chronic tobacco smoke exposure and stress. This method is effective for analyzing the relationship between long-term tobacco smoke exposure and chronic stress. Full article

Background: Our recent studies indicate that astrocytes in a key mesocorticolimbic region play an important role in nicotine reinforcement. Nicotine self-administration elevated the astrocyte marker glial fibrillary acidic protein (GFAP) in the nucleus accumbens (NAc) core. Metabolic inhibition of astrocytes in the NAc core with fluorocitrate attenuated nicotine self-administration and disrupted local extracellular glutamate and dopamine transmission. Cotinine is the major neuroactive metabolite of nicotine, demonstrating its own reinforcing effects and contributing to the development of nicotine reinforcement. Mechanisms underlying cotinine reinforcement remain underexplored. The objective of this study was to investigate the potential involvement of astrocytes in cotinine reinforcement. Methods: GFAP protein expression was measured in key mesocorticolimbic regions with a Western blot following chronic cotinine self-administration. The effects of fluorocitrate on cotinine self-administration and extracellular glutamate and dopamine levels were determined. Results: GFAP protein levels were higher in rats undergoing chronic cotinine self-administration than in those with saline self-administration within the ventral tegmental area (VTA) but not the nucleus accumbens or the medial prefrontal cortex. Intra-VTA microinjection of fluorocitrate inhibited the maintenance of cotinine self-administration. Perfusion of fluorocitrate in the VTA reduced local extracellular levels of glutamate and dopamine. Conclusions: These results indicate that cotinine self-administration augmented GFAP expression in the VTA and that metabolic inhibition of VTA astrocytes attenuated cotinine self-administration and impaired extracellular dopamine and glutamate transmission. Overall, these findings suggest that astrocytes in the VTA may play an important role in cotinine reinforcement, potentially through regulation of local extracellular glutamate and dopamine transmission. Full article

The increasing use of electronic cigarettes (e-cigarettes) highlights the need for accessible and reliable biomarkers to assess nicotine exposure. Fingernails represent a non-invasive and stable keratin matrix capable of capturing the long-term incorporation of xenobiotics such as cotinine, the primary metabolite of nicotine. This study aimed to optimise cotinine extraction from fingernails using Response Surface Methodology (RSM) with a central composite design prior to quantification by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Three extraction variables were evaluated: NaOH concentration, extraction temperature, and extraction time. Numerical optimisation identified the optimal conditions as 3.74 M NaOH, 50 °C, and 40 min, yielding a predicted recovery of 84.06% with a high desirability value of 0.973. The calibration curve demonstrated excellent linearity (R² = 0.9998), with a limit of detection of 14.5 µg kg⁻¹ and a limit of quantification of 43.8 µg kg⁻¹. The RSM model exhibited strong predictive performance, with an R² of 0.9990, an adjusted R² of 0.9982, and a predicted R² of 0.9958, supported by a non-significant lack of fit and robust residual diagnostics. Application of the optimised protocol to real fingernail samples successfully differentiated e-cigarette smokers from non-smokers based on characteristic cotinine-associated FTIR spectral features and quantitative measurements, demonstrating the practical utility of the proposed method. Overall, this study establishes a rapid, chromatography-free, and cost-effective analytical approach for monitoring long-term nicotine exposure using keratin-based matrices. Full article