Investigation of the role of 8-OHdG and oxidative stress in papillary thyroid carcinoma

The effects of iodine 131 treatment on chromosomal and oxidative DNA damage in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is a common endocrine cancer with a good prognosis. Radioactive iodine is thought to be useful for individuals who have had a total or almost total thyroidectomy, but its effects are still controversial. The effects of radioactive iodine-131 (I-131) treatment on oxidative and chromosomal damage in PTC patients were examined in this study, which was carried out with 16 patients newly diagnosed with PTC and 20 healthy control subjects with similar age and gender. Blood samples were taken from patients with PTC at five sampling times (before total thyroidectomy, after total thyroidectomy, and seven days, six months, and one year after treatment) and from control subjects. The cytokinesis block micronucleus cytome (CBMN-cyt) assay parameters in peripheral blood lymphocytes of patients with PTC and controls were evaluated and plasma 8-hydroxydeoxyguanosine (8-OHdG) levels were measured. Furthermore, genome instability and oxidative DNA damage in peripheral blood lymphocytes and plasma of patients with PTC were evaluated before total thyroidectomy (n=16), after total thyroidectomy (before I-131 treatment) (n=16), seven days (n=10), six months (n=5), and one year after treatment (n=5). The numbers of CBMN-cyt assay parameters (micronucleus; MN and nucleoplasmic bridges; NPB) and 8-OHdG levels in patients with PTC were determined to be significantly higher than in those of the control subjects and these values significantly decreased after total thyroidectomy (before I-131 treatment). While the number of MN, apoptotic, and necrotic cells increased after I-131 treatment, it significantly decreased after six months and one year after treatment. The results achieved in this study suggest that I-131 treatment may pose a threat to cells and that radioactive iodine therapy should be avoided (if possible) for patients with PTC after total thyroidectomy.

Enhancing Angioinvasion Assessment in Papillary Thyroid Cancer Via a Biomarker Panel Involving TAC, 8-OHdG, and Sortilin

CONTEXT

Papillary thyroid cancer (PTC) aggressiveness and metastatic potential are closely associated with angioinvasion. Identifying angioinvasion accurately is imperative for treatment planning and prognosis.

OBJECTIVE

This study explores serum biomarkers, including 8-hydroxydeoxyguanosine (8-OHdG) and oxidative status markers (total oxidative capacity, total antioxidant capacity [TAC], and sortilin), as potential indicators of angioinvasion in PTC.

DESIGN

A cross-sectional study involving 50 angioinvasive patients with PTC (study group) and 30 patients with PTC with low-risk features (reference group). Serum levels of biomarkers were analyzed to determine their association with angioinvasion.

SETTING

Patients were recruited from Department of Endocrinology, Diabetology, and Internal Diseases, Medical University of Bialystok, Poland, ensuring representation from a diverse clinical context.

PATIENTS OR OTHER PARTICIPANTS

Participants included patients with PTC, with 50 in the study group and 30 in the reference group. Selection criteria, matching characteristics, and participant completion rates were duly recorded.

INTERVENTION(S)

Serum biomarkers were measured to evaluate their association with PTC angioinvasion.

MAIN OUTCOME MEASURE(S)

Primary outcome measures included serum levels of 8-OHdG, total oxidative capacity, TAC, and sortilin.

RESULTS

Serum levels of 8-OHdG and sortilin were significantly elevated in angioinvasive PTC, whereas TAC showed a notable decrease (all P < .01). A regression panel combining TAC, 8-OHdG, and sortilin demonstrated a high area under the curve value (0.963) for angioinvasion discernment.

CONCLUSION

Measuring TAC, 8-OHdG, and sortilin levels may serve as potential biomarkers for identifying angioinvasion in PTC. The combined assessment of these biomarkers enhances angioinvasion discernment, aiding risk stratification and personalized treatment decisions. Further validation studies are required before integrating these biomarkers into routine clinical practice. The study adheres to the provided structure, providing concise and supported conclusions based on the results.

The role of DNA and RNA guanosine oxidation in cardiovascular diseases

Cardiovascular diseases (CVD) persist as a prominent cause of mortality worldwide, with oxidative stress constituting a pivotal contributory element. The oxidative modification of guanosine, specifically 8-oxoguanine, has emerged as a crucial biomarker for oxidative stress, providing novel insights into the molecular underpinnings of CVD. 8-Oxoguanine can be directly generated at the DNA (8-oxo-dG) and RNA (8-oxo-G) levels, as well as at the free nucleotide level (8-oxo-dGTP or 8-oxo-GTP), which are produced and can be integrated through DNA replication or RNA transcription. When exposed to oxidative stress, guanine is more readily produced in RNA than in DNA. A burgeoning body of research surrounds 8-oxoguanine, exhibits its accumulation playing a pivotal role in the development of CVD. Therapeutic approaches targeting oxidative 8-Oxoguanine damage to DNA and RNA, encompassing the modulation of repair enzymes and the development of small molecule inhibitors, are anticipated to enhance CVD management. In conclusion, we explore the noteworthy elevation of 8-oxoguanine levels in patients with various cardiac conditions and deliberate upon the formation and regulation of 8-oxo-dG and 8-oxo-G under oxidative stress, as well as their function in CVD.

Diabetes Mellitus and Thyroid Cancers: Risky Correlation, Underlying Mechanisms and Clinical Prevention

The incidences of thyroid cancer and diabetes are rapidly increasing worldwide. The relationship between thyroid cancer and diabetes is a popular topic in medicine. Increasing evidence has shown that diabetes increases the risk of thyroid cancer to a certain extent. This mechanism may be related to genetic factors, abnormal thyroid-stimulating hormone secretion, oxidative stress injury, hyperinsulinemia, elevated insulin-like growth factor-1 levels, abnormal secretion of adipocytokines, and increased secretion of inflammatory factors and chemokines. This article reviews the latest research progress on the relationship between thyroid cancer and diabetes, including the association between diabetes and the risk of developing thyroid cancer, its underlying mechanisms, and potential anti-thyroid cancer effects of hypoglycemic drugs. It providing novel strategies for the prevention, treatment, and improving the prognosis of thyroid cancer.

Could Oxidative Stress Play a Role in the Development and Clinical Management of Differentiated Thyroid Cancer?

Increased oxidative stress (OS) has been implicated as a relevant risk factor for cancer progression. Furthermore, patients diagnosed with differentiated thyroid cancer (DTC) have been characterized by an increased OS status. Therefore, assessing OS status could potentially be considered a useful tool in DTC clinical management. This measurement could be particularly valuable in personalizing treatment protocols and determining new potential medical targets to improve commonly used therapies. A literature review was conducted to gather new information on DTC clinical management, with a particular focus on evaluating the clinical utility of OS. These meta-analyses concentrate on novel approaches that employ the measurement of oxidative-antioxidant status, which could represent the most promising area for implementing clinical management.

Oxidative stress mediates the associations between phthalate exposures and thyroid cancer/benign nodule risk

Epidemiological studies have suggested that phthalate exposures are associated with increased risks of thyroid cancer and benign nodule, while the underlying mechanisms are largely unknown. Here, we explored the mediation effects of oxidative stress (OS) biomarkers in the associations between phthalate exposures and the risks of thyroid cancer and benign nodule. Urine samples collected from 143 thyroid cancer, 136 nodule patients, and 141 healthy controls were analyzed for 8 phthalate metabolites and 3 OS biomarkers [8-hydroxy-2-deoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), and 8-iso-prostaglandin F_2α (8-isoPGF_2α)]. Multivariable linear or logistic regression models were used to explore the associations of OS biomarkers with phthalate metabolite concentrations and the risks of thyroid cancer and nodule. The mediation role of OS biomarkers was also investigated. Urinary monoethyl phthalate (MEP), monomethyl phthalate (MMP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP), mono (2-ethylhexyl) phthalate (MEHP), and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) were positively associated with at least 2 OS biomarkers (all P-values<0.01), and part of these positive associations varied in different subgroups. All 3 OS biomarkers were positively associated with the risks of thyroid nodule and cancer (P-values<0.001). The mediation analysis showed that OS biomarkers significantly mediated the associations between urinary MEHOP concentration and nodule, as well as between urinary MMP, MEHP, and MEHHP concentrations and cancer and nodule, with the estimated proportions of mediation ranging from 15.8% to 85.6%. Our results suggest that OS is a potential mediating mechanism through which phthalate exposures induce thyroid carcinogenesis and nodular formation.

Research progress in human biological monitoring of aromatic hydrocarbon with emphasis on the analytical technology of biomarkers

Aromatic hydrocarbons are unsaturated compounds containing carbon and hydrogen that form single aromatic ring, or double, triple, or multiple fused rings. This review focuses on the research progress of aromatic hydrocarbons represented by polycyclic aromatic hydrocarbons (including halogenated polycyclic aromatic hydrocarbons), benzene and its derivatives including toluene, ethylbenzene, xylenes (o-, m- and p-), styrene, nitrobenzene, and aniline. Due to the toxicity, widespread coexistence, and persistence of aromatic hydrocarbons in the environment, accurate assessment of exposure to aromatic hydrocarbons is essential to protect human health. The effects of aromatic hydrocarbons on human health are mainly derived from three aspects: different routes of exposure, the duration and relative toxicity of aromatic hydrocarbons, and the concentration of aromatic hydrocarbons which should be below the biological exposure limit. Therefore, this review discusses the primary exposure routes, toxic effects on humans, and key populations, in particular. This review briefly summarizes the different biomarker indicators of main aromatic hydrocarbons in urine, since most aromatic hydrocarbon metabolites are excreted via urine, which is more feasible, convenient, and non-invasive. In this review, the pretreatment and analytical techniques are compiled systematically for the qualitative and quantitative assessments of aromatic hydrocarbons metabolites such as gas chromatography and high-performance liquid chromatography with multiple detectors. This review aims to identify and monitor the co-exposure of aromatic hydrocarbons that provides a basis for the formulation of corresponding health risk control measures and guide the adjustment of the exposure dose of pollutants to the population.

A biochemical and histology experimental approach to investigate the adverse effect of chronic lead acetate and dietary furan on rat lungs

Despite lead widespread environmental pollution, its effect on humans and livestock's respiratory systems remains inadequately investigated. Similarly, furan is industrially relevant with enormous environmental presence. Lead and furan can be ingested -via lead pipes contaminated water and heat-treated food respectively. Thus, humans are inadvertently exposed continuously. Lead toxicity is well studied, and furan have earned a position on the IARC's list of carcinogens. Here, we evaluate the effect of co-exposure to lead and furan on rat lungs. Thirty Wistar rats were grouped randomly into six cohorts (n = 6) consisting of a control group, furan alone group, lead acetate (PbAc) alone group and three other groups co-exposure to graded PbAc (1, 10 & 100 µg/L) alongside a constant furan (8 mg/kg) dose. After twenty-eight days, enzymatic and non-enzymatic antioxidant, oxidative stress and inflammatory biomarkers were biochemically evaluated. The ELISA-based technique was used to measure oxidative-DNA damage (8-OHG), tumour protein 53 (TP53) expressed and tumour necrotic factor-alpha (TNF-α) level. Dose-dependent increases (p < 0.05) in reactive oxygen and nitrogen species, malondialdehyde, nitric oxide, myeloperoxidase, TNF-α and TP53 level, with an associated decrease (p < 0.05) in enzymatic and non-enzymatic antioxidants were observed in the furan, PbAc and the co-treated rats relative to the control. In addition, PbAc and furan treatment impaired the histoarchitectural structures of rat lungs, exemplified by pro-inflammatory cell infiltration and trafficking into the bronchioles and alveolar spaces. Co-exposure to furan and PbAc may contribute to lung dysfunction via loss of redox balance, genomic damage/instability, inflammation and disrupted histoarchitectural features.

Urinary concentrations of phenols, oxidative stress biomarkers and thyroid cancer: Exploring associations and mediation effects

Phenols have been shown to influence the cellular proliferation and function of thyroid in experimental models. However, few human studies have investigated the association between phenol exposure and thyroid cancer, and the underlying mechanisms are also poorly understood. We conducted a case-control study by age- and sex-matching 143 thyroid cancer and 224 controls to investigate the associations between phenol exposures and the risk of thyroid cancer, and further to explore the mediating role of oxidative stress. We found that elevated urinary triclosan (TCS), bisphenol A (BPA) and bisphenol S (BPS) levels were associated with increased risk of thyroid cancer (all P for trends < 0.05), and the adjusted odds ratios (ORs) comparing the extreme exposure groups were 3.52 (95% confidence interval (CI): 2.08, 5.95), 2.06 (95% CI: 1.06, 3.97) and 7.15 (95% CI: 3.12, 16.40), respectively. Positive associations were also observed between urinary TCS, BPA and BPS and three oxidative stress biomarkers measured by 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F_2α (8-isoPGF_2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), as well as between urinary 8-isoPGF_2α and HNE-MA and the risk of thyroid cancer. Mediation analysis showed that urinary 8-isoPGF_2α mediated 28.95%, 47.06% and 31.08% of the associations between TCS, BPA and BPS exposures and the risk of thyroid cancer, respectively (all P < 0.05). Our results suggest that exposure to TCS, BPA and BPS may be associated with increased risk of thyroid cancer and lipid peroxidation may be an intermediate mechanism. Further studies are warranted to confirm the findings.

Early life parameters and personality affect oxidative status during adulthood in an altricial rodent

It is increasingly recognized that alterations of the cellular oxidative status might be an important cost underlying challenging early life conditions. For example, an increased litter size can impose challenges as the offspring will face increased competition for maternal resources. Within a litter, individuals with relatively higher starting mass typically show higher growth rates, which can lead to increased oxidative damage. We investigated the long-term consequences of these early life parameters on the oxidative status in mature mound-building mice (Mus spicilegus). Individual differences in the animals' exploration tendency were assessed by repeated open field and novel object tests. We predicted less exploratory phenotypes, which typically show a higher stress responsiveness, to be particularly susceptible to possible effects of these early life parameters on oxidative status. We quantified oxidative damage of DNA (8-hydroxy-2'-deoxyguanosine levels, 8-OHdG) and proteins (protein carbonyl content, PCC), and activities of the antioxidants catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) in liver and skeletal muscle tissue. 8-OHdG levels were positively associated with CAT and SOD in both tissues, indicating that increased oxidative DNA damage was associated with an upregulation of antioxidant production. Hepatic DNA damage after maturity was increased in animals from larger litters. In less exploratory animals, DNA damage and the activity of CAT and SOD in the muscle were increased, but only in individuals with higher relative starting mass (measured on postnatal day 9). This interaction may be explained by the typically higher adrenocortical activity in less exploratory phenotypes and by the higher growth in relatively heavier pups, two factors known to increase oxidative stress. These findings contribute to enlightening the complex interplay between early life conditions, personality, and oxidative status.

PRDX4 Potentially Predicts the Postoperative Outcome in Advanced Papillary Thyroid Carcinoma

Background: Peroxiredoxin 4 (PRDX4), a secreted antioxidant enzyme, can protect against hepatocellular carcinoma and lung adenocarcinoma, but its role in papillary thyroid carcinoma (PTC) is still unclear. In this study, we investigated the association of the PRDX4 expression with the prognosis of patients with advanced PTC. Methods: We conducted a retrospective case-control study at Kanazawa Medical University Hospital. We selected PTC patients over 55 years of age who received surgery from 2006 to 2014. The PRDX4 expression was immunohistochemically analyzed in paraffin-embedded tumor specimens of 70 patients with stages Ⅱ–Ⅳ advanced PTC. We also investigated the key roles of PRDX4 in a human PTC cell line (K-1) in vitro. Result: The weak expression of PRDX4 was found to be significantly associated with recurrence. In a multivariate analysis, the weak expression of PRDX4—rather than other pathological features of high invasiveness—predicted a poor prognosis. In vitro, the viability of human PTC cells was significantly suppressed after PRXD4 plasmid transfection. Conclusion: The weak expression of PRDX4 can predict recurrence with a potential poor prognosis in advanced PTC.

Anti-proliferative and apoptotic effects of hull-less pumpkin extract on human papillary thyroid carcinoma cell line

Papillary thyroid carcinoma (PTC) is one of the most common cancers of the endocrine system. Previous studies have shown that the extract of hull-less pumpkin seed (HLPS) has a significant anti-cancer effect. The aim of this study was to evaluate the effect of this plant extract on the proliferation of PTC cells. In this study, an extract of this plant was prepared by soxhlet extraction method and analyzed by Gas Chromatography-Mass Spectrometry. The cytotoxicity of PTX and plant extract was investigated using the methylthiazol tetrazolium (MTT) method. For careful investigation of morphological alteration, we used hematoxylin and eosin and Giemsa stinging. Based on MTT assay test, the IC₅₀ value of paclitaxel (PTX) was significantly less than the hydro-alcoholic extract of HLPS at all of the incubation time. Our results of histological staining showed that HLPS and PTX induced significant morphological alteration in the PTC cultured cell that consistent with cell death. Comparing the groups treated by PTX or HLPS with control group showed significant differences. It seems that HLPS extract has an apparent effect on treatment of PTC, at least in laboratory condition, albeit for realistic decision about the effect of HLPS on PTC, more molecular investigations are necessary.

Redox Status and Antioxidative Cofactor Metals Influence Clinical and Pathological Characteristics of Papillary Thyroid Carcinoma and Colloid Goiter

Papillary thyroid carcinoma (PTC) is the endocrine neoplasm that occurs the most often worldwide, and its molecular pathophysiology is still not well characterized. Redox status is recognized as an important factor of carcinogenesis, but its influence on the PTC's clinical course needs to be better elucidated. The aim of this research was to determine the tissue redox status of 65 PTC and 45 colloid goiter (CG) patients together with antioxidative cofactor metal profiling. The malondialdehyde (MDA) concentration was used to access the prooxidation level, while antioxidant mechanisms were estimated by assaying the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). The antioxidative cofactor metals included quantification of Se, Cu, Zn, and Mn concentration. PTC tissues had normal prooxidation levels and increased GPx and GR activity. The activity of SOD has been significantly reduced in multicentric PTC dissemination and increased in smokers. SOD activity was directly dependent on MDA levels in CG tissues. CG patients with retrosternal goiter had reduced MDA concentration and SOD activity. Numerous correlations between redox parameters in PTC tissues reveal good co-activation of antioxidative mechanisms and cooperative response on prooxidation. PTC tissues had decreased Se levels and increased concentration of Cu and Mn in comparison to other tissues. MDA concentration and SOD activity were significant predictors of PTC's multicentric dissemination and for the existence of lymph node metastases, respectively. Particularly, the concentration of Cu predicted the retrosternal localization in CG patients. Significant findings presented in this study provide a possibility for development of novel prognostic molecular biomarkers of PTC and CG.

A methylomics-associated nomogram predicts recurrence-free survival of thyroid papillary carcinoma

Background

Thyroid papillary carcinoma (TPC) is the most common type of thyroid cancer (TC). The prognosis of TPC patients with tumor‐cell metastasis is poor. Therefore, this study aims to develop a model for predicting TPC patients' recurrence‐free survival (RFS).

Methods

We included 546 TPC patients who were clinically and pathologically diagnosed with TPC. The methylation biomarkers that associate with RFS were explored. These 546 samples were divided into training dataset (first 70%) and validation dataset (remaining 30%) randomly. The training dataset was used to identify prognostic biomarkers and construct risk prediction model, in addition, the validation dataset was used to verify the predictive performance of the model. We used Cox proportional hazard analysis and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis to identify the significant predictive biomarkers, and establish the relapse risk prediction model from the identified biomarkers.

Results

A 6‐DNA methylation signature yielded a high evaluative performance for RFS. The Kaplan‐Meier analysis indicated that the 6‐DNA methylation signature could significantly distinguish the high‐ and low‐risk patients in training, validation and entire sets. In addition, a nomogram was constructed based on risk score, metastasis status and residual tumor status, and C‐index, receiver operating characteristic (ROC) and the calibration plots analysis which demonstrated the good performance and clinical utility of the nomogram.

Conclusions

The results suggested that the 6‐DNA methylation signature is the independent prognostic marker for RFS and functioned as a significant tool for guiding the clinical treatment of TPC patients.

Effects of Tomato Juice Intake on Salivary 8-Oxo-dG Levels as Oxidative Stress Biomarker after Extensive Physical Exercise

Reactive oxygen species (ROS) at a normal level are important molecules involved in several cellular processes including immune response and cell signalling. Overproduction of ROS may lead to elevated oxidative stress and consequently to age-related diseases. Most of the studies related to oxidative stress in humans have been done on blood samples. However, blood sampling might be painful, requires special qualified personnel, and has to be performed at medical centers. An alternative to blood is saliva. Saliva sampling is noninvasive and can be performed by the donor. Biomarker determination in saliva is becoming an important part of laboratory diagnosis, but method development is needed before it can be used in the clinics. In the present investigation, 16 donors performed extensive physical exercise by cycling and keeping their heart rate at 80% of maximum for 20 minutes. The physical activity was repeated 3 times: before tomato juice intake, after daily intake of 100 ml tomato juice during 3 weeks, and finally 3 weeks after finishing tomato juice intake (washout period). The level of the stress biomarker, salivary 8-oxo-dG, was determined before and after the physical activity. The results indicate that (a) 20 min extensive physical activity increases the level of 8-oxo-dG in saliva significantly (p = 0.0078) and (b) daily intake of 100 ml tomato juice may inhibit (p = 0.052) overproduction of salivary 8-oxo-dG by 20 min physical activity. We conclude that the 20 min extensive physical activity increases the level of salivary 8-oxo-dG in healthy donors and 100 ml daily intake of tomato juice may inhibit the increase of 8-oxo-dG in saliva.

Possible differences in the mechanism of malignant transformation of HaCaT cells by arsenite and its dimethyl metabolites, particularly dimethylthioarsenics

BACKGROUND

As a confirmed human carcinogen, arsenic can cause skin cancer, lung cancer, etc. However, its carcinogenic mechanism is still unclear. In recent years, the oxidative stress hypothesis has become widely accepted. In mammals it has been found that arsenic can be converted to dimethylarsinous acid (DMAIII) and dimethylmonothioarsinic acid (DMMTAV) through a series of methylation and redox reactions. DMAIII and DMMTAV are highly toxic.

METHODS

Human keratinocytes (HaCaT) were exposed to different concentrations of NaAsO2 (IAsIII), DMMTAV and DMAIII for 24 h. Reactive oxygen species (hydrogen peroxide and superoxide), oxidative damage markers (8-hydroxydeoxyguanosine and malondialdehyde), and antioxidant markers (glutathione and superoxide dismutase) were measured. In addition, sulfane sulfurs were measured in HaCaT cells and a cell-free system.

RESULTS

In the DMMTAV and DMAIII treatment groups, the levels of hydrogen peroxide and superoxide in HaCaT cells were higher than in the IAsIII treatment groups at the same dose. Levels of 8-OHdG and MDA in the DMMTAV and DMAIII treatment groups were also higher than those in the IAsIII treatment groups at the same dose. However, in the DMMTAV and DMAIII treatment groups, the levels of GSH and SOD activity were lower than that in the IAsIII treatment groups. In DMMTAV-treated HaCaT cells, sulfane sulfurs were produced. Further, it was found that DMMTAV could react with DMDTAV to form persulfide in the cell-free system, which may explain the mechanism of the formation of sulfane sulfurs in DMMTAV-treated HaCaT cells.

CONCLUSIONS

DMMTAV and DMAIII more readily induce reactive oxygen species (ROS) and cause oxidative damage in HaCaT cells than inorganic arsenic. Further, the persulfide formed by the reaction of DMMTAV and DMDTAV produced from the metabolism of DMMTAV may induce a stronger reductive defense mechanism than GSH against the intracellular oxidative stress of DMMTAV. However, the cells exposed to arsenite are transformed by the continuous nuclear translocation of Nrf2 due to oxidative stress, and the persulfide from dimethylthioarsenics may promote Nrf2 by the combination with thiol groups, especially redox control key protein, Keap1, eventually cause nuclear translocation of sustained Nrf2.

Melatonin reduces high levels of lipid peroxidation induced by potassium iodate in porcine thyroid

Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO₃) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO₃ possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO₃ in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO₃ without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO₃ was used. Homogenates were incubated in presence of KIO₃ (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO₃ increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO₃ at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO₃ used in doses resulting in physiological iodine concentrations in the thyroid.

Relative telomere length and oxidative stress in musculoskeletal tumors

Telomeres are capped at the end of the chromosome and gradually shorten when the cell divides. When there is an oxidative stress, it can cause the DNA to be damaged. Hence, 8-hydroxy-2'-deoxyguanosine (8-OHdG) has been shown to be an indicator for oxidative DNA damage. This study aimed to determine the relative telomere length (RTL) and 8-OHdG levels in neoplastic tissues, adjacent non-neoplastic tissues, and blood leukocytes of musculoskeletal (MS) tumor patients. Neoplastic tissues were compared to adjacent non-neoplastic tissues in MS tumor patients (n = 46). Peripheral blood leukocytes (PBLs) of MS tumor subjects were compared to those of age-matched healthy controls (n = 107). RTL was evaluated by quantitative real-time polymerase chain reaction and 8-OHdG levels were quantified by enzyme-linked immunosorbent assay. The RTL in neoplastic tissues was significantly shorter than that in non-neoplastic tissues [1.12 (0.86-1.46) vs 1.45 (1.25-1.65), P = 0.001]. PBLs had lower RTL than non-neoplastic tissues in MS tumor patients [1.04 (0.85-1.13) vs 1.45 (1.25-1.65), P < 0.001]. However, there was no significant difference between RTL in PBLs and in neoplastic tissues. In addition, PBLs of MS tumor patients had higher RTL than those of the controls [1.04 (0.85-1.13) versus 0.78 (0.68-0.90), P < 0.001]. The 8-OHdG levels in neoplastic tissues were remarkably higher than those in non-neoplastic tissues [8.14 (6.81-11.37) nM/μg/μl vs. 3.79 (2.53-6.17) nM/μg/μl, P < 0.001]. Furthermore, plasma 8-OHdG levels in MS tumor patients were markedly greater than those in the controls [102.50 (73.16-133.50) nM vs. 41.09 (6.81-11.37) nM, P < 0.001]. Area under the curve (AUC) was 0.7536 (95% confident interval (CI) 0.6602-0.8469) when the cut-off value of RTL in PBLs was 0.97. Also, plasma 8-OHdG levels depicted that when the cut-off value was 38.67 nM, the AUC was 0.7723 (95% CI 0.6920-0.8527). Moreover, ROC curve analysis showed that both RTL and 8-OHdG appeared to improve the sensitivity (85.68%) and specificity (70.91%) with the AUC 0.8639 (95% CI 0.7500-0.9500). This study suggested that blood leukocyte RTL and plasma 8-OHdG could serve as promising non-invasive biomarkers to differentiate between MS tumor patients and healthy controls. Additionally, telomere attrition and increased oxidative DNA damage might play contributory roles in the pathogenesis of MS tumors.

Approaches and Methods to Measure Oxidative Stress in Clinical Samples: Research Applications in the Cancer Field

Reactive oxygen species (ROS) are common by-products of normal aerobic cellular metabolism and play important physiological roles in intracellular cell signaling and homeostasis. The human body is equipped with antioxidant systems to regulate the levels of these free radicals and maintain proper physiological function. However, a condition known as oxidative stress (OS) occurs, when ROS overwhelm the body's ability to readily detoxify them. Excessive amounts of free radicals generated under OS conditions cause oxidative damage to proteins, lipids, and nucleic acids, severely compromising cell health and contributing to disease development, including cancer. Biomarkers of OS can therefore be exploited as important tools in the assessment of disease status in humans. In the present review, we discuss different approaches used for the evaluation of OS in clinical samples. The described methods are limited in their ability to reflect on OS only partially, revealing the need of more integrative approaches examining both pro- and antioxidant reactions with higher sensitivity to physiological/pathological alternations. We also provide an overview of recent findings of OS in patients with different types of cancer. Identification of OS biomarkers in clinical samples of cancer patients and defining their roles in carcinogenesis hold great promise in promoting the development of targeted therapeutic approaches and diagnostic strategies assessing disease status. However, considerable data variability across laboratories makes it difficult to draw general conclusions on the significance of these OS biomarkers. To our knowledge, no adequate comparison has yet been performed between different biomarkers and the methodologies used to measure them, making it difficult to conduct a meta-analysis of findings from different groups. A critical evaluation and adaptation of proposed methodologies available in the literature should therefore be undertaken, to enable the investigators to choose the most suitable procedure for each chosen biomarker.

Electrochemical analysis of 8-hydroxy-2'-deoxyguanosine with enhanced sensitivity based on exonuclease-mediated functional nucleic acid

In this work, an electrochemical method for sensitive analysis of 8-hydroxy-2'-deoxyguanosine, a key biomarker that is widely used to study oxidative injury-related diseases, is proposed based on exonuclease-mediated functional nucleic acid. In the design, exonuclease can not only distinguish the existence of target, but also suppress the background noise, thus the sensitivity can be enhanced. Moreover, DNAzyme designed in the functional nucleic acid can further improve the sensitivity of the analysis during signal generation process. Therefore, exonuclease-mediated functional nucleic acid may ensure high sensitivity of the assay. Further studies reveal that the detection of 8-hydroxy-2'-deoxyguanosine can be achieved with a linearity from 0.01 nM to 7.0 μM and a detection limit of 6.82 pM. The new method has also been successfully applied to the determination of 8-OHdG in urine with good results, indicating its great potential for practical use.

8-Hydroxy-2’-deoxyguanosine as a biomarker of oxidative stress in acute exacerbation of chronic obstructive pulmonary disease

Background/aim

8-Hydroxy-2’-deoxyguanosine (8-OHdG) is a biomarker of oxidative stress and has been implicated in many diseases. The aim of this study was to investigate the clinical value of plasma 8-OHdG level in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Materials and methods

A total of 154 subjects were enrolled in this study, including 20 healthy volunteers, 24 COPD patients in the stable phase, and 110 AECOPD patients. Peripheral blood samples, demographic information, and clinical characteristics were collected from all subjects at the time of being recruited into the study. Plasma 8-OHdG level was detected by enzyme-linked immunosorbent a ss ay.

Results

8-OHdG was increased in patients with AECOPD compared to healthy subjects and patients with stable COPD, especially in smokers. It also increased with the GOLD stage, mMRC grade, CAT score, and group level of combined COPD assessment. Additionally, further analysis revealed that 8-OHdG was negatively correlated with FEV1, FEV1% predicted, and FEV1/FVC and positively correlated with C-reactive protein, procalcitonin, and neutrophil CD64.

Conclusion

8-OHdG is associated with spirometric severity, symptomatic severity, exacerbation risk, and inflammatory biomarkers in AECOPD patients, suggesting it as a promising biomarker for reflecting disease severity and guiding the choice of optimal therapeutic decision.

Serum 8-Oxo-dG as a Predictor of Sensitivity and Outcome of Radiotherapy and Chemotherapy of Upper Gastrointestinal Tumours

The level of oxidative stress is important in the initiation and progression of various age-related diseases, such as cancer. The level of oxidative stress may also play a significant role in cancer patients' response to treatment. We aimed to investigate whether serum 8-oxo-dG as a marker of oxidative stress is a predictor of tumour response. We used modified ELISA with a two-step filtration to analyse 8-oxo-dG in serum. The relationship between 8-oxo-dG levels, tumour response, and toxicity was studied in 19 oesophageal cancer patients who received radiotherapy and 16 gastric cancer patients who received chemotherapy. In the radiotherapy and the merged radio- and chemotherapy groups, the baseline levels of 8-oxo-dG were significantly lower in responder patients than in nonresponder patients and the increments after treatment were greater. In comparison with patients whose serum 8-oxo-dG levels decrease after treatment, patients with increasing levels had a longer median “progression-free survival.” Our results, although preliminary, suggest that serum levels of 8-oxo-dG may potentially be used to predict the sensitivity and outcome of radiotherapy and chemotherapy of upper gastrointestinal tumours. Patients with 8-oxo-dG levels that are low prior to treatment and subsequently increase after treatment may be more likely to benefit from the therapy.

Overexpression of teneurin transmembrane protein 1 is a potential marker of disease progression in papillary thyroid carcinoma

Although papillary thyroid cancer is a relatively indolent malignancy, its progression may be associated with dedifferentiation and resistance to radioactive iodine treatment. In this study, patterns of differentially expressed genes in association with disease progression were systemically evaluated. We firstly performed transcriptome analyses for four matched cancerous and noncancerous tissue pairs of the classical subtype of papillary thyroid cancer. Among the upregulated and downregulated genes, the expression of 164 and 183 genes increased and decreased, respectively, from stage I to stage IV. Functional enrichment and pathway analysis showed that angiogenesis pathway was upregulated, whereas oxidation-reduction and metabolism of reactive oxygen species were downregulated. Teneurin transmembrane protein 1 (TENM1) expression was highly upregulated in cancerous tissues and negative in benign thyroid tissues. By immunohistochemistry, TENM1 expression in papillary thyroid cancer was associated with the classical subtype (p = 0.018), extrathyroidal invasion (p = 0.001), BRAF V600E mutation (p < 0.001), and an advanced stage (p = 0.019). Taken together, our results indicate that distinct pathways are involved in papillary thyroid cancer progression, and TENM1 is a potential marker of cancer progression.

The plasma 8-OHdG levels and oxidative stress following cholecystectomy: a randomised multicentre study of patients with minilaparotomy cholecystectomy versus laparoscopic cholecystectomy

OBJECTIVE

The aim of the study was to evaluate the role of 8-OHdG (8-hydroxy-2'-deoxyguanosine) detecting oxidative stress response following cholecystectomy in a randomised multicentre study of patients with minilaparotomy cholecystectomy (MC) versus laparoscopic cholecystectomy (LC).

METHODS

Initially, 106 patients with non-complicated symptomatic gallstone disease were randomised into MC (n = 56) or LC (n = 50) groups. Plasma levels of the oxidative stress marker 8-OHdG measured at three time points; before (PRE), immediately after (POP1) and 6 h after operation (POP2).

RESULTS

The demographic variables and the surgical data were similar in the study groups. The plasma oxidative stress marker 8-OHdG concentrations following surgery in the MC versus LC patients were quite similar. There was no significant correlation between the individual values of the11-point numeric rating pain scale (NRS) versus the plasma 8-OHdG post-operatively in the MC and LC patients. However, there was a statistically significant correlation between the individual values of the plasma 8-OHdG (PRE) versus IL-10 (PRE) for the MC and LC patients (r = 0.214, p = 0.037). There was also a statistically significant correlation between the individual values of the plasma 8-OHdG (POP2) versus IL-1β (POP2) for the MC and LC patients (r = 0.25, p = 0.01).

CONCLUSION

Our results suggest that the oxidative stress marker 8-OHdG concentrations following surgery in MC versus LC patients were quite similar. A new finding with possible clinical relevance is a correlation between the individual plasma values of the 8-OHdG versus anti-inflammatory interleukin IL-10 and 8-OHdG versus IL-1β (proinflammatory) in the MC and LC patients suggesting that inflammation and oxidative stress are related.

Measuring Oxidative DNA Damage With 8-Hydroxy-2'-Deoxyguanosine Levels in Patients With Laryngeal Cancer

OBJECTIVES

8-Hydroxy-2'-deoxyguanosine is a biomolecule associated with DNA damage. We evaluated oxidative stress and DNA damage in patients with laryngeal cancer by measuring 8-hydroxy-2'-deoxyguanosine levels.

METHODS

This study enrolled 117 subjects, including 64 controls and 53 patients who had benign vocal cord lesions or laryngeal cancer. The benign excised lesions, tumor tissue, noncancerous laryngeal tissue, blood, and urine were subjected to high-performance liquid chromatography, and 8-hydroxy-2'-deoxyguanosine levels were compared between groups.

RESULTS

Blood and urine 8-hydroxy-2'-deoxyguanosine levels in patients with laryngeal carcinoma were significantly higher than in the controls ( P = .00002, P = .00001). The 8-hydroxy-2'-deoxyguanosine level was significantly higher in tumor tissues than in non-tumor tissue and benign vocal cord lesion tissues ( P = .00002, P = .000001).

CONCLUSIONS

We determined that laryngeal cancer was associated with oxidative stress, which may be quantified by measuring 8-hydroxy-2'-deoxyguanosine. For a patient with a suspicious laryngeal lesion, 8-hydroxy-2'-deoxyguanosine levels in blood and urine can provide advance information about the likely diagnosis.

Functional polymorphisms in antioxidant genes in Hurthle cell thyroid neoplasm - an association of GPX1 polymorphism and recurrent Hurthle cell thyroid carcinoma

Background

Hurthle cells of the thyroid gland are very rich in mitochondria and oxidative enzymes. As a high level oxidative metabolism may lead to higher level of oxidative stress and can be associated with an increased risk for cancer, we investigated whether common functional polymorphisms in antioxidant genes (SOD2, CAT, GPX, GSTP1, GSTM1 and GSTT1) are associated with the development or clinical course of Hurthle cell thyroid carcinoma (HCTC).

Methods

A retrospective study was performed in 139 patients treated by thyroid surgery for a Hurthle cell neoplasm. HCTC, Hurthle cell thyroid adenoma (HCTA) or Hurthle cell thyroid nodule (HCTN) were diagnosed by pathomorphology. DNA was extracted from cores of histologically confirmed normal tissue obtained from formalin-fixed paraffin-embedded specimens and genotyped for investigated polymorphisms. Logistic regression was used to compare genotype distributions between patient groups.

Results

HCTC, HCTA and HCTN were diagnosed in 53, 47 and 21 patients, respectively. Metastatic disease and recurrence of HCTC were diagnosed in 20 and 16 HCTC patients, respectively. Genotypes and allele frequencies of investigated polymorphisms did not deviate from Hardy-Weinberg equilibrium in patients with HCTC, HCTA and HCTN. Under the dominant genetic model we observed no differences in the genotype frequency distribution of the investigated polymorphisms when the HCTA and HCTN group was compared to the HCTC group for diagnosis of HCTC or for the presence of metastatic disease. However, GPX1 polymorphism was associated with the occurrence of recurrent disease (p = 0.040).

Conclusions

GPX1 polymorphism may influence the risk for recurrent disease in HCTC.

Oxidative stress and DNA damage in patients with migraine

BACKGROUND

Oxidative stress is implicated in the pathogenesis of migraine, but no published studies have examined both oxidative stress levels and oxidative DNA damage on the same patient group.

METHODS

In this study, total oxidant status (TOS); total antioxidant status (TAS); oxidative stress index (OSI); and 8-hydroxy-2'-deoxyguanosine (8-OHdG), which is an indicator of oxidative DNA damage, were measured in the plasma samples of 50 prophylactic unmediated migraineurs (11 with aura and 39 without aura) and 30 matched healthy volunteers.

RESULTS

No significant differences in TAS, TOS, and OSI values were observed between patients and controls. However, plasma 8-OHdG levels were found to be significantly higher in migraine patients than in the control group (p = 0.001); this increase in plasma 8-OHdG levels was more prominent in cases with migraine without aura than with aura (p = 0.001). Our results suggested an evidence of oxidative stress-related DNA damage in migraine.

CONCLUSION

DNA damage reflected by plasma 8-OHdG did not studied in migraine before. Therefore, further research on oxidative stress-related DNA damage and the extent of its clinical manifestations in migraine may provide additional data to our current knowledge.

Serum calprotectin: a new potential biomarker for thyroid papillary carcinoma

The aim of this study was to evaluate serum calprotectin levels and oxidative stress status in patients with papillary thyroid carcinoma (PTC) and the changes in their levels after total thyroidectomy. The study involved 30 patients with PTC and 30 healthy controls. Blood samples were obtained from the PTC patients before and 1 month after the operation. Preoperative and postoperative serum samples from PTC patients and healthy controls were analysed for calprotectin, total antioxidant status (TAS), total oxidant status (TOS) and lipid hydroperokside (LOOH). The preoperative calprotectin, TOS, OSI and LOOH levels of the patients with PTC were significantly higher compared to those of the control group (p < 0.001, for each). The levels of calprotectin decreased significantly in patients with PTC after the operation (p < 0.001), while TAS, TOS and OSI levels remained unchanged (p = 0.313, p = 0.085 and p = 0.163, respectively). Preoperative serum calprotectin levels were positively correlated with TOS, OSI and LOOH levels and negatively correlated with TAS levels in patients with PTC. In conclusion, serum calprotectin levels is increased in patients with PTC, and calprotectin is positively correlated with TOS and LOOH. Serum calprotectin levels is significantly decreased after total thyroidectomy.

Bioinformatics analyses of significant prognostic risk markers for thyroid papillary carcinoma

This study was aimed to identify the prognostic risk markers for thyroid papillary carcinoma (TPC) by bioinformatics. The clinical data of TPC and their microRNAs (miRNAs) and genes expression profile data were downloaded from The Cancer Genome Atlas. Elastic net-Cox's proportional regression hazards model (EN-COX) was used to identify the prognostic associated factors. The receiver operating characteristic (ROC) curve and Kaplan-Meier (KM) curve were used to screen the significant prognostic risk miRNA and genes. Then, the target genes of the obtained miRNAs were predicted followed by function prediction. Finally, the significant risk genes were performed literature mining and function analysis. Total 1046 miRNAs and 20531 genes in 484 cases samples were identified after data preprocessing. From the EN-COX model, 30 prognostic risk factors were obtained. Based on the 30 risk factors, 3 miRNAs and 11 genes were identified from the ROC and KM curves. The target genes of miRNA-342 such as B-cell CLL/lymphoma 2 (BCL2) were mainly enriched in the biological process related to cellular metabolic process and Disease Ontology terms of lymphoma. The target genes of miRNA-93 were mainly enriched in the pathway of G1 phase. Among the 11 prognostic risk genes, v-maf avian musculoaponeurotic fibrosarcoma oncogene homologue F (MAFF), SRY (sex-determining region Y)-box 4 (SOX4), and retinoic acid receptor, alpha (RARA) encoded transcription factors. Besides, RARA was enriched in four pathways. These prognostic markers such as miRNA-93, miRNA-342, RARA, MAFF, SOX4, and BCL2 may be used as targets for TPC chemoprevention.