Assessment of exposure and DNA damage from second-hand smoke using potential biomarker in urine: cigarettes and heated tobacco products.

Second-hand smoke exposure is an established cause of several adverse health effects. Tobacco smoke exposure in the environment has been improved by the WHO Framework Convention on Tobacco Control. However, concerns have been raised regarding the health effects of heated tobacco products. Analysis of tobacco smoke biomarkers is critical for assessing the health effects of second-hand tobacco smoke exposure. In this study, nicotine metabolites (nicotine, cotinine, trans-3'-hydroxycotinine) and carcinogenic 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol were analysed in the urine of non-smokers with or without passive exposure to cigarettes and heated tobacco products. In addition, 7-methylguanine and 8-hydroxy-2'-deoxyguanosine were simultaneously measured as DNA damage markers. The results revealed higher levels of urinary nicotine metabolites and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in participants exposed to second-hand tobacco smoke (both cigarettes and heated tobacco products) at home. In addition, the urinary levels of 7-methylguanine and 8-hydroxy-2'-deoxyguanosine tended to be higher in the second-hand tobacco smoke-exposed group. The urinary levels of nicotine metabolites and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol were high in workplaces with no protection against passive smoking. These biomarkers will be useful for evaluating passive exposure to tobacco products.

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.

Diurnal and day-to-day variation of urinary oxidative stress marker 8-hydroxy-2'-deoxyguanosine.

The urinary 8-hydroxy-2'-deoxyguanosine levels have been widely used as a biomarker of oxidative stress. The purpose of this study is to investigate the diurnal and day-to-day variations of urinary 8-hydroxy-2'-deoxyguanosine levels. For the diurnal variation, the urine samples were collected at the time of awakening and every 2 h, from 10:00 to 22:00, from 6 healthy participants. For the day-to-day variation, the urine samples were collected at the time of awakening for 35 consecutive days, from 27 healthy participants. As a result, no differences were observed in the diurnal urinary 8-hydroxy-2'-deoxyguanosine levels, and each subject had a characteristic 8-hydroxy-2'-deoxyguanosine level. On the other hand, the daily 8-hydroxy-2'-deoxyguanosine values showed a certain range of variation reflecting lifestyle factors, such as stress status, exercise, sleep time, drinking and diet. In conclusion, urinary 8-hydroxy-2'-deoxyguanosine may be a useful biomarker to control and prevent oxidative stress-related diseases, if the certain range of day-to-day variations of urinary 8-hydroxy-2'-deoxyguanosine is known. Even with only one measurement per year, the baseline urinary 8-hydroxy-2'-deoxyguanosine level could be achieved in a few years by incorporating the 8-hydroxy-2'-deoxyguanosine measurement as part of an annual health check. As the number of subjects was limited, further studies are needed for practical applications.

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.

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

Oxidative stress is a risk factor for lifestyle-related diseases, such as cancer. Investigations of the factors that increase or decrease oxidative stress contribute to disease prevention. In the present study, we focused on the 8-hydroxyguanine (8-OHGua) in saliva, as a new oxidative stress biomarker. The relationship between lifestyles and salivary 8-OHGua levels in 541 Japanese subjects was analyzed. The salivary 8-OHGua levels were significantly elevated in older persons, as well as those who smoke, have hypertension, or excess visceral fat. By contrast, statistically significant lower levels of 8-OHGua were observed in persons who moderately exercised or recently drank green tea or coffee. The direct collection of saliva, without any special collecting device, was suitable for the 8-OHGua analysis. The present results suggest that oxidative stress can be measured in a non-invasive manner with easily collectable saliva, and the salivary 8-OHGua may be a useful biomarker for lifestyle-related disease prevention.

[Workers' Lifestyles and Urinary 8-hydroxydeoxyguanosine as an Oxidative Stress Marker].

Oxidative stress in biological components has become recognized as one of the causative factors of various diseases. In this study, we investigated the effects of worker lifestyle and fatigue on the levels of urinary 8-hydroxydeoxyguanosine (8-OHdG), a marker of oxidative stress. Our results revealed that urinary 8-OHdG level was increased by alcohol intake and decreased by snack intake and adequate sleep time on the day before the survey. A decrease in urinary 8-OHdG level was also observed in parallel with a decrease in workload. Urinary 8-OHdG monitoring is expected to be useful for disease prevention in the future.

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.

Pilot clinical study of ascorbic acid treatment in cardiac catheterization.

Clinical radiodiagnosis and radiotherapy sometimes induce tissue damage and/or increase the risk of cancer in patients. However, in radiodiagnosis, a reduction in the exposure dose causes a blockier image that is not acceptable for diagnosis. Approximately 70% of DNA damage is induced via reactive oxygen species and/or radicals created during X-ray irradiation. Therefore, treatment with anti-oxidants and/or radical scavengers is considered to be effective in achieving a good balance between image quality and damage. However, few studies have examined the effect of using radical scavengers to reduce radiation damage in the clinical setting. In this study, we administrated 20 mg/kg ascorbic acid (AA) to patients before cardiac catheterization (CC) for diagnostic purposes. We analyzed changes in the number of phosphorylated H2AX (γH2AX) foci (a marker of DNA double-strand breaks) in lymphocytes, red blood cell glutathione levels, blood cell counts, and biochemical parameters. Unfortunately, we did not find satisfactory evidence to show that AA treatment reduces γH2AX foci formation immediately after CC. AA treatment did, however, cause a higher reduced/oxidized glutathione ratio than in the control arm immediately after CC. This is a preliminary study, but this result suggests that reducing radiation damage in clinical practice can be achieved using a biological approach.

Pyrimidine Ring-Opened Product from Oxidative DNA Damage of 5-Formyl-2'-deoxyuridine.

After thymidine (dT) was treated with a Fenton-type reagent and further incubated for a long period (6 days) under physiological conditions (37 °C, pH 7.4), a new product, named dT*, was detected by HPLC in addition to the free thymine base and the known oxidative dT damage, 5-formyl-2'-deoxyuridine (f5dU). dT* was found to be formed from f5dU. The structure of dT* was determined to be 3-amino-2-carbamoyl-2-propenal-N3-2'-deoxyriboside, a pyrimidine ring-opened product from f5dU, on the basis of 1H- and 13C NMR analyses and mass spectra. From the model compound 1-methyl-5-formyluracil, a similar ring-opened product was formed after the incubation. dT* was also detected in DNA treated with a Fenton-type reagent or γ-rays, followed by the prolonged incubation. dT* will be a new promising marker of oxidative DNA damage. The possible role of this product in oxy-radical-induced mutagenesis is discussed.

Ratio between estimated glomerular filtration rates of creatinine and cystatin C predicts overall survival in patients with hepatocellular carcinoma.

AIM: Hepatocellular carcinoma (HCC) patients with sarcopenia have a poor survival, but there are no predictive markers for survival relating to muscle mass and liver function. Therefore, we investigated whether the ratio between estimated glomerular filtration rates of serum creatinine (Scre) and serum cystatin C (Scys) (eGFRcre/eGFRcys) can be used as a predictive marker of survival in HCC patients. METHODS: First, the correlation between Scre/Scys ratio and muscle mass was examined in 50 patients with chronic liver disease. Second, a change in Scre/Scys ratio relating to liver function was investigated in cirrhotic rats. Finally, the relationship between the eGFRcre/eGFRcys ratio and survival was assessed in 86 HCC patients. RESULTS: The Scre/Scys ratio was correlated with skeletal muscle mass index (r = 0.331, P = 0.019) and psoas muscle area index (r = 0.397, P = 0.004) in chronic liver disease patients. In cirrhotic rats, Scre and Scre/Scys ratio were decreased corresponding with liver function. Thirty-five of 86 HCC patients died within the average follow-up period of 35 months. The patients with an eGFRcre/eGFRcys ratio <1.26 had significantly longer rates of survival compared to patients with an eGFRcre/eGFRcys ratio ≥1.26 (28.8 vs. 18.5 months, P = 0.001). Using multivariate Cox regression analyses, the patient-related eGFRcre/eGFRcys ratio (hazard ratio [HR], 4.178; P = 0.007), as well as the tumor-related factors α-fetoprotein (HR, 1.000; P < 0.001) and Barcelona Clinic Liver Cancer stage (HR, 2.589; P < 0.001), were independent predictors of survival. CONCLUSION: The Scre/Scys ratio is associated with muscle mass and liver function. Furthermore, the eGFRcre/eGFRcys ratio could serve as a useful predictive marker for survival of HCC.

Oxidative DNA damage in the rat lung induced by intratracheal instillation and inhalation of nanoparticles.

Nanoparticles are widely used as useful industrial materials. Therefore, their possible adverse health effects must be appraised. We assessed and compared the oxidative DNA damage caused by four different nanoparticles (TiO2, NiO, ZnO and CeO2). The effects of the administration methods, intratracheal instillation and inhalation, were also evaluated. Rats were subjected to intratracheal instillations or 4 weeks of inhalation exposure to the nanoparticles, and the 8-hydroxydeoxyguanosine (8-OHdG) levels in the lung were analyzed by an HPLC-EC detector method. The 8-OHdG levels were increased in a dose-dependent manner with the inhalation of NiO. ZnO also increased the 8-OHdG levels with inhalation. In comparison with the control, the 8-OHdG levels were significantly and persistently higher with the CeO2 nanoparticle administration, by both intratracheal instillation and inhalation. In contrast, there were no significant differences in the 8-OHdG levels between the control and TiO2 nanoparticle-treated groups, with either intratracheal instillation or inhalation during the observation period. These results indicated that NiO, ZnO and CeO2 nanoparticles generate significant amounts of free radicals, and oxidative stress may be responsible for the lung injury caused by these nanoparticles. In addition, both intratracheal instillation and inhalation exposure induced similar tendencies of oxidative DNA damage with these nanoparticles.

Measurement of 8-hydroxyguanine as an oxidative stress biomarker in saliva by HPLC-ECD.

INTRODUCTION: Oxidative stress leads to many kinds of diseases. Currently, urinary 8-hydroxydeoxyguanosine (8-OHdG) is widely measured as an oxidative stress biomarker. There is a specific advantage if saliva can be used as the sample to measure the oxidative stress biomarker, because saliva is much easier to collect than urine. In this study, we investigated the measurement of 8-hydroxyguanine (8-OHGua) as an oxidative stress marker in saliva, by a column switching HPLC system equipped with an electrochemical detector (HPLC-ECD). FINDINGS: The 8-OHGua in saliva could be detected as a single peak by HPLC-ECD. The average level of 8-OHGua in saliva was 3.80 ng/mL in ordinary, non-smoking subjects. The salivary 8-OHGua levels of smokers were significantly higher than those of non-smokers. CONCLUSIONS: Salivary 8-OHGua may be a useful noninvasive and promising oxidative stress biomarker.

Antioxidant properties of green tea aroma in mice.

Green tea ('Sencha'), made from the leaves of Camellia sinensis, is the most well-researched antioxidant beverage. The major source of its antioxidant activity is polyphenols, consisting mainly of catechins (flavan-3-ols). However, little is known about the physiological effects of green tea aroma, which lacks catechins. In the present study, we performed inhalation experiments with green tea aroma to evaluate its antioxidant activity in mice. As a result, the urinary 8-hydroxydeoxyguanosine levels were significantly decreased in comparison with those of the non-treated group, and the serum antioxidant capacity was significantly increased by the inhalation administration of green tea aroma. Furthermore, the increase in the urinary 8-hydroxydeoxyguanosine levels due to whole-body X-ray irradiation was significantly suppressed by the inhalation of green tea aroma. This is the first study to show the antioxidant activity of green tea aroma in vivo.

Identification of octenal-related dA and dC adducts formed by reactions with a hemin-ω-6-fat peroxidation model system.

Deoxynucleosides were reacted in a lipid peroxidation model system, emulsified hemin-ethyl linoleate, and the adducts thus produced were analyzed by HPLC. Substantial amounts of stable adducts were detected in the dA- and dC-reaction mixtures. The structures of the major dA and dC adducts, other than the known 4-oxo-2-nonenal adducts, were determined to be etheno-type adducts, with a C6 side chain bearing an α-hydroxyl-group. These results suggested that the substance involved in adduct formation is 2,3-epoxyoctanal. This compound showed mutagenicity in Salmonella strains TA 100 and TA 104 without the S-9 mix. In addition, based on the structure of a minor dC adduct, another possibly involved mutagen, 4-oxo-2-octenal, was proposed. These mutagens may be formed during storage and cooking of food, or during digestion, and may be involved in human cancers.