Salivary 8-hydroxyguanine as a lifestyle-related oxidative stress biomarker in workers

Evaluation and comparison of DNA alkylation and oxidative damage in e-cigarette and heated tobacco users

OBJECTIVES

This study, aimed to determine and compare DNA damage in e-cigarette and HTP (IQOS) users by assessing DNA-adducts, which are biomarkers of various DNA alkylation and oxidation.

METHODS

For the evaluation of DNA alkylation, N3-Ethyladenine (N3-EtA) and N3-Methyladenine (N3-MeA) adducts were used. DNA oxidation was assessed using, 8-hydroxy-2'-deoxyguanosine(8-OHdG). The urinary cotinine, N3-MeA, N3-EtA, and 8-OHdG concentrations of the cigarette smokers (n:39), e-cigarette users (n:28), IQOS users (n:20), passive smokers (n:32), and nonsmokers(n:41) who lived Ankara, Turkiye were determined using, liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

In light of the detected 8-OHdG levels, e-cigarette (3.19 ng/g creatinine) and IQOS (4.38 ng/g creatinine) users had higher oxidative DNA damage than healthy nonsmokers (2.51 ng/g creatinine). Alkylated DNA-adducts were identified in the urine of e-cigarette (N3-MeA: 3.92 ng/g creatinine; N3-EtA: 0.23 ng/g creatinine) and IQOS (N3-MeA: 7.54 ng/g creatinine; N3-EtA: 0.29 ng/g creatinine) users. In the generation of N3-MeA adducts, a significant difference was found between IQOS users and e-cigarette users (p < 0.05). Also, DNA alkylation in flavored e-cigarette users (N3-MeA: 4.51 ng/g creatinine; N3-EtA: 0.27 ng/g creatinine) was higher than in non-flavored e-cigarette users (N3-MeA: 2.27 ng/g creatinine; N3-EtA: 0.06 ng/g creatinine). The highest cotinine levels were found in cigarette smokers (16.1316 ng/g creatinine). No significant difference was found when e-cigarette (1163.02 ng/g creatinine) and IQOS smokers were compared (1088.3 ng/g creatinine).

CONCLUSION

People who use e-cigarettes and IQOS may be at higher risk of genotoxicity than those who do not use and are not exposed to any tobacco products. Furthermore, the usage of flavoring additives in e-cigarettes contributed to additional genotoxic damage risks.

Comprehensive assessment of Zingiber sianginensis: Phytometabolomic analysis and its impact on oxidative stress biomarkers

In India, ginger is highly valued for cultural and medicinal purposes. Besides traditional uses, ginger has been proven for its efficacy in cancer, chemotherapy-induced nausea, bacterial infections, neuroinflammation, and oxidative stress. This study focuses on Zingiber sianginensis, a rare ginger species in the Siang region of Arunachal Pradesh, India. This study studied pharmacognostical evaluation, phytometabolomics analysis, and its effect on oxidative stress biomarkers. Microscopic and chemical tests were employed for pharmacognostical evaluation, revealing distinctive characteristics of Zingiber sianginensis, such as non-close collateral vascular bundles and unique cork layers. Chemical tests, including the phloroglucinol and hydrochloric acid test, differentiated Zingiber sianginensis from Zingiber officinale Roscoe. Phytometabolomics analysis, using Gas Chromatography-Mass Spectrometry (GC/MS) and Liquid Chromatography-Electrospray Ionisation-Quadrupole Time of Flight-Mass Spectrometry (LC-ESI-QTOF-MS/MS) techniques, identified a diverse range of metabolites in Zingiber sianginensis, including polyphenols, monoterpenoids, diterpenoids, sesquiterpenoids, and organic compounds. The LC-ESI-QTOF-MS/MS analysis revealed 158 compounds, verified through cross-referencing with established databases. Heavy metal analysis by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) confirmed that Zingiber sianginensis complies with safety standards, showing concentrations of heavy metals within acceptable limits. The isolation and characterization of compounds from Zingiber sianginensis identified natural products such as (R)-(-)- alpha-Curcumene (1), 1-Dehydro-[10]-gingerdione (2), 6-Shogaol (3), and 6-Gingerol (4). Quantification of 6-gingerol revealed that Zingiber sianginensis contains approximately twice the amount compared to Zingiber officinale Roscoe's, suggesting its potential as a source for higher 6-gingerol content. The hydroalcoholic extract of Zingiber sianginensis exhibited antioxidant properties, reducing oxidative stress biomarkers in human dermal fibroblast cells treated with rotenone. Allantoin and 3-bromotyrosine levels significantly decreased, indicating the extract's potential in combating oxidative stress-related disorders. Overall, this comprehensive study provides valuable insights into the pharmacognostical, phytometabolomic, and safety aspects of Zingiber sianginensis, highlighting its potential as a source of bioactive compounds with health benefits.

The Role of Potential Oxidative Biomarkers in the Prognosis of Acute Ischemic Stroke and the Exploration of Antioxidants as Possible Preventive and Treatment Options

Ischemic strokes occur when the blood supply to a part of the brain is interrupted or reduced due to arterial blockage, and it often leads to damage to brain cells or death. According to a myriad of experimental studies, oxidative stress is an important pathophysiological mechanism of ischemic stroke. In this narrative review, we aimed to identify how the alterations of oxidative stress biomarkers could suggest a severity-reflecting diagnosis of ischemic stroke and how these interactions may provide new molecular targets for neuroprotective therapies. We performed an eligibility criteria-based search on three main scientific databases. We found that patients with acute ischemic stroke are characterized by increased oxidative stress markers levels, such as the total antioxidant capacity, F2-isoprostanes, hydroxynonenal, total and perchloric acid oxygen radical absorbance capacity (ORACTOT and ORACPCA), malondialdehyde (MDA), myeloperoxidase, and urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine. Thus, acute ischemic stroke is causing significant oxidative stress and associated molecular and cellular damage. The assessment of these molecular markers could be useful in diagnosing ischemic stroke, finding its causes, predicting its severity and outcomes, reducing its impact on the cellular structures of the brain, and guiding preventive treatment towards antioxidant-based therapy as novel therapeutic alternatives.

8-oxoguanine and 8-oxodeoxyguanosine Biomarkers of Oxidative DNA Damage: A Review on HPLC-ECD Determination

Reactive oxygen species (ROS) are continuously produced in living cells due to metabolic and biochemical reactions and due to exposure to physical, chemical and biological agents. Excessive ROS cause oxidative stress and lead to oxidative DNA damage. Within ROS-mediated DNA lesions, 8-oxoguanine (8-oxoG) and its nucleotide 8-oxo-2'-deoxyguanosine (8-oxodG)-the guanine and deoxyguanosine oxidation products, respectively, are regarded as the most significant biomarkers for oxidative DNA damage. The quantification of 8-oxoG and 8-oxodG in urine, blood, tissue and saliva is essential, being employed to determine the overall effects of oxidative stress and to assess the risk, diagnose, and evaluate the treatment of autoimmune, inflammatory, neurodegenerative and cardiovascular diseases, diabetes, cancer and other age-related diseases. High-performance liquid chromatography with electrochemical detection (HPLC-ECD) is largely employed for 8-oxoG and 8-oxodG determination in biological samples due to its high selectivity and sensitivity, down to the femtomolar range. This review seeks to provide an exhaustive analysis of the most recent reports on the HPLC-ECD determination of 8-oxoG and 8-oxodG in cellular DNA and body fluids, which is relevant for health research.

Urinary biomarkers for secondhand smoke and heated tobacco products exposure

Concerns have recently grown about the health effects of secondhand smoke exposure and heated tobacco products. The analysis of tobacco smoke biomarkers is critical to assess the health effects of tobacco smoke exposure. For this purpose, the simultaneous determinations of exposure markers and health effect markers would provide a better evaluation of smoke exposure. In this study, nicotine metabolites (nicotine, cotinine, trans-3'-hydroxycotinine) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in urine were analyzed as exposure markers. The DNA damage markers, 7-methylguanine and 8-hydroxy-2'-deoxyguanosine, were simultaneously measured as health effect markers. The results revealed significant levels of urinary nicotine metabolites and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in the subjects exposed to secondhand smoke and heated tobacco products. In addition, the urinary levels of 7-methylguanine and 8-hydroxy-2'-deoxyguanosine tended to be high for secondhand smoke and heated tobacco products exposures, as compared to those of non-smokers. These biomarkers will be useful for evaluating tobacco smoke exposure.

Health examination results and work environment factors affecting urinary 8-hydroxy-2'-deoxyguanosine levels

OBJECTIVE

Oxidative stress is considered to cause lifestyle-related diseases, including cancer. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) is widely analyzed as an oxidative stress marker. We extensively scrutinized the relationships between 8-OHdG levels and lifestyle choices as carcinogenic factors.

METHODS

In this study, we investigated health examination results and working conditions affecting urinary 8-OHdG levels in 503 male workers.

RESULTS

The urinary 8-OHdG level was positively associated with high blood sugar and leanness in smokers. In addition, urinary 8-OHdG tended to increase with organic solvent or hydrochloric acid exposure, as well as long working hours. On the other hand, the urinary 8-OHdG level was negatively associated with high plasma LDL-cholesterol levels in non-smokers and anemia.

CONCLUSION

According to the results, anemia decreased the oxidative stress, regardless of smoking status, while leanness or high blood sugar increased the oxidative stress in smokers, and the presence of plasma cholesterol contributed to the lower oxidative stress in non-smokers. Certain types of occupational exposure may cause oxidative stress. The measurement of urinary 8-OHdG at annual health checks may be a useful biomarker for preventing lifestyle- and work-related diseases.

Effects of smoking cessation on biological monitoring markers in urine

INTRODUCTION

Urinary nicotine and cotinine levels are often measured as biomarkers for tobacco smoke exposure. However, these biomarkers are not appropriate to evaluate the effects of quitting smoking for several days, because of their short half-lives. In this study, we focused on the changes in the urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) levels of 55 patients in a smoking cessation program, because of the long half-life. At the same time, urinary 7-methylguanine (m7Gua) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), as DNA damage markers of cigarette smoking, were also measured.

RESULTS

In the subjects who completed the quit-smoking program (18 subjects out of 55), the urinary nicotine and cotinine levels decreased to 1.7 and 0.2% at 8 weeks after the first visit to the clinic. By contrast, the NNAL levels decreased to 12.3% at 8 weeks after quitting smoking. During the same period, the urinary m7Gua levels significantly decreased, from 27.32 μg/mg creatinine to 14.17 μg/mg creatinine by the elimination of subjects who showed increased levels of NNAL during the smoking cessation program. The 8-OHdG levels were also reduced within the same period, but were not significantly different. From the all data analysis, the urinary levels of cotinine and NNAL positively correlated with the level of m7Gua.

CONCLUSIONS

NNAL may be an appropriate exposure marker for evaluating the smoking status of patients in a smoking cessation program. The urinary cotinine and NNAL levels positively correlated with the m7Gua levels.

Diurnal variation of salivary oxidative stress marker 8-hydroxyguanine

INTRODUCTION

Oxidative stress is a risk factor for life-style related diseases, including cancer. We recently reported that the oxidative stress marker 8-hydroxyguanine (8-OHGua) can be measured in saliva non-invasively. Understanding the diurnal pattern of salivary 8-OHGua levels is crucial for evaluating the oxidative stress. In this study, we analyzed the diurnal variation of salivary 8-OHGua levels.

FINDINGS

The salivary 8-OHGua levels were relatively stable in the daytime (10:00-22:00). The daytime 8-OHGua levels seemed to represent the individual oxidative stress status. The average amount and the variation of the salivary 8-OHGua levels immediately after awakening were higher than those of the daytime levels.

CONCLUSIONS

The 8-OHGua levels in saliva exhibited diurnal variation. The levels were higher at the time of awakening. At this point, the daytime levels of salivary 8-OHGua may be appropriate for evaluating the individual oxidative stress status. Further study is needed for understanding and utilizing the 8-OHGua levels at the time of awakening.