Nitrosative Stress Biomarkers in the Non-Stimulated and Stimulated Saliva, as well as Gingival Crevicular Fluid of Patients with Periodontitis: Review and Clinical Study

The Effect of Antidepressant Treatment on Neurocognitive Functions, Redox and Inflammatory Parameters in the Context of COVID-19

Inflammation is an important component of the etiopathology of depression that uses oxidative and nitrosative stress (O&NS) and elevated inflammatory markers. SARS-CoV-2 infection is also associated with abnormal inflammatory processes, which may impair effective treatment of depression in COVID-19 survivors. In the presented study, thirty-three hospitalized patients with major depressive disorder (MDD) were started on antidepressant treatment, and twenty-one were re-evaluated after 4-6 weeks. The control group consisted of thirty healthy volunteers. All participants underwent neuropsychiatric evaluation, biochemical blood and urine analyses. The results of the research demonstrated positive correlations of the Hamilton Depression Rating Scale (HAM-D) scores with serum catalase (CAT) and urinary S-Nitrosothiols levels, and the Beck Depression Inventory (BDI) scores with serum reduced glutathione (GSH) and superoxide dismutase (SOD) levels. Depressed patients with a history of COVID-19 prior to the treatment had higher urinary nitric oxide (NO) levels and lower serum glutathione peroxidase (GPx) levels. In the control group, COVID-19 survivors had higher levels of urinary N-formylkynurenine (NFK). Our results suggest that the antidepressant treatment has a modulating effect on O&NS, reduces depressive symptoms and improves cognitive functions The present study does not indicate that clinical response to antidepressant treatment is associated with COVID-19 history and baseline SARS-CoV-2 antibody levels. Nevertheless, further research in this area is needed to systematize antidepressant treatment in COVID-19 survivors.

Enzymatic antioxidants activity in gingival crevicular fluid and saliva in advanced periodontitis

AIM

Enzymatic antioxidants are the primary line of defense against oxidative and nitrosative stress. However, their involvement in the progression of periodontitis is still not well understood. The study aimed to determine the activity of enzymatic antioxidants in the gingival crevicular fluid (GCF) and saliva of patients with periodontitis.

MATERIALS AND METHODS

The study group of 56 patients with periodontitis (stage III and IV) and 28 healthy controls were involved. The modified plaque index, probing depth, the clinical attachment level, the percentage of sites with bleeding on probing, papilla bleeding index, and maximum value of tooth mobility (Periotest®) were tested. Saliva (stimulated and non-stimulated) and GCF were collected from the participants, and activity of peroxidase, catalase, superoxide dismutase, and glutathione reductase were determined colorimetrically.

RESULTS

Lower activity of peroxidase (p < 0.0001), catalase (p < 0.0001), superoxide dismutase (p = 0.0188), and glutathione reductase (p < 0.0001) was noted in non-stimulated saliva of patients with periodontitis compared to healthy subjects. Peroxidase (p < 0.0001), catalase (p < 0.0001) and superoxide dismutase (p < 0.0001) showed lower activity in stimulated saliva of patients with periodontitis compared to healthy subjects. The peroxidase (p < 0.0029), catalase (p < 0.0001), and glutathione reductase (p = 0.0028) activity in GCF of stage III + IV were significantly higher compared to healthy controls. Superoxide dismutase (p < 0.0001) showed lower activity in GCF of patients with periodontitis.

CONCLUSIONS

The demonstrated decrease in activity of all analyzed enzymatic antioxidants in non-stimulated saliva may result from long-lasting periodontitis and exhaustion of the safeguard mechanism against reactive oxygen species.

Meta-Analysis of Assessment of Total Oxidative Stress and Total Antioxidant Capacity in Patients with Periodontitis

Background

Periodontitis is intricately linked to oxidative stress-antioxidant (redox) imbalance. The antioxidant system scavenges the oxygen free radicals in biological fluids in patients with periodontitis. However, little is still known about the free radicals mediated oxidative stress and reductive ability of the antioxidant system. Thus, the present meta-analysis aims to quantitatively review the literature that assessed the oxidative stress marker total oxidative stress (TOS) and total antioxidant capacity (TAC) in various biological fluids of patients with periodontitis. Methodology. Electronic databases were searched for studies that assessed TOS and TAC levels in various biological samples of patients with periodontitis.

Results

From the 1,812 articles identified, 1,754 were excluded based on title and abstract screening due to irrelevance to the topic of interest. A full-text assessment of the remaining 58 articles led to the selection of 42 articles that satisfied the inclusion criteria. Of these, only 24 studies had consistent data for quantitative analysis. The periodontitis group displayed significantly elevated TOS levels (p < 0.05) in serum, gingival crevicular fluid (GCF), and saliva samples in the studies evaluated. In contrast, the periodontitis group exhibited significantly attenuated TAC levels (p < 0.01) compared to healthy controls in plasma, serum, and GCF samples of the studies evaluated, which was insignificant in salivary samples (p=0.433). At the same time, the periodontitis group displayed insignificantly elevated TAC levels after periodontal therapy (p=0.130).

Conclusions

The present meta-analysis showed significantly higher TOS and lower TAC in periodontitis, reflecting the elevated oxidative stress level than the control group. Clinical Relevance. Scientific rationale for the study: The imbalance between oxidants and antioxidants (oxidative stress (OS)) plays a critical role in the onset and progression of periodontitis; the assessment of the relationship between OS-related biomarkers in regional samples and systemic samples of patients with periodontitis helps us to evaluate the periodontal disease progression. The OS biomarker levels can be used to assess periodontal disease and therapeutic efficacy.

Impact of Circulating Cell-Free DNA (cfDNA) as a Biomarker of the Development and Evolution of Periodontitis

In the last few decades, circulating cell-free DNA (cfDNA) has been shown to have an important role in cell apoptosis or necrosis, including in the development and evolution of several tumors and inflammatory diseases in humans. In this regard, periodontitis, a chronic inflammatory disease that can induce the destruction of supporting components of the teeth, could represent a chronic inflammatory stimulus linked to a various range of systemic inflammatory diseases. Recently, a possible correlation between periodontal disease and cfDNA has been shown, representing new important diagnostic-therapeutic perspectives. During the development of periodontitis, cfDNA is released in biological fluids such as blood, saliva, urine and other body fluids and represents an important index of inflammation. Due to the possibility of withdrawing some of these liquids in a non-invasive way, cfDNA could be used as a possible biomarker for periodontal disease. In addition, discovering a proportional relationship between cfDNA levels and the severity of periodontitis, expressed through the disease extent, could open the prospect of using cfDNA as a possible therapeutic target. The aim of this article is to report what researchers have discovered in recent years about circulating cfDNA in the development, evolution and therapy of periodontitis. The analyzed literature review shows that cfDNA has considerable potential as a diagnostic, therapeutic biomarker and therapeutic target in periodontal disease; however, further studies are needed for cfDNA to be used in clinical practice.

Pathways Linking Oral Bacteria, Nitric Oxide Metabolism, and Health

Nitrate-reducing oral bacteria have gained a lot of interest due to their involvement in nitric oxide (NO) synthesis and its important cardiometabolic outcomes. Consortia of nitrate-metabolizing oral bacteria associated with cardiometabolic health and cognitive function have been recently identified. Longitudinal studies and clinical trials have shown that chronic mouthwash use is associated with increased blood pressure and increased risk for prediabetes/diabetes and hypertension. Concurrently, recent studies are beginning to shed some light on the complexity of nitrate reduction pathways of oral bacteria, such as dissimilatory nitrate reduction to ammonium (DNRA), which converts nitrite into ammonium, and denitrification, which converts nitrite to NO, nitrous oxide, and dinitrogen. These pathways can affect the composition and metabolism of the oral microbiome; consequently, salivary nitrate and nitrite metabolism have been proposed as targets for probiotics and oral health. These pathways could also affect systemic NO levels because NO generated through denitrification can be oxidized back to nitrite in the saliva, thus facilitating flux along the NO₃^--NO₂^--NO pathway, while DNRA converts nitrite to ammonium, leading to reduced NO. It is, therefore, important to understand which pathway predominates under different oral environmental conditions, since the clinical consequences could be different for oral and systemic health. Recent studies show that oral hygiene measures such as tongue cleaning and dietary nitrate are likely to favor denitrifying bacteria such as Neisseria, which are linked with better cardiometabolic health. A vast body of literature demonstrates that redox potential, carbon-to-nitrate ratio, and nitrate-to-nitrite ratio are key environmental drivers of the competing denitrification and DNRA pathways in various natural and artificial ecosystems. Based on this information, a novel behavioral and microbial model for nitric oxide metabolism and health is proposed, which links lifestyle factors with oral and systemic health through NO metabolism.

Cross-Talk Between Nitrosative Stress, Inflammation and Hypoxia-Inducible Factor in Patients with Adrenal Masses

Background

Adrenal masses are the most common of all human tumors. The role of nitrosative stress and inflammation in cancer development has already been demonstrated. However, it is not known whether they are involved in the pathogenesis of adrenal tumors. The aim of the study was to investigate a cross-talk between nitrosative stress, inflammation and hypoxia-inducible factor (HIF-1α) in 75 patients with different types of adrenal masses (non-functional incidentaloma, pheochromocytoma and Cushing's/Conn's adenoma).

Methods

The plasma concentrations of total nitric oxide (NO), S-nitrosothiols, peroxynitrite nitrotyrosine and the activity of serum myeloperoxidase (MPO) were measured spectrophotometrically, whereas concentrations of interleukin 1 beta (IL-1β), tumor necrosis factor α (TNF-α) and hypoxia-inducible factor 1 alpha (HIF-1α) were measured using commercial ELISA kits. The control group consisted of 50 healthy people matched by age and sex to the study group. The number of subjects was determined a priori based on our previous experiment (power of the test = 0.9; α = 0.05).

Results

We found significantly higher nitrosative stress (↑nitric oxide, ↑peroxynitrite, ↑S-nitrosothiols and ↑nitrotyrosine) in the plasma of patients with adrenal tumors, which was accompanied by increased inflammatory (↑myeloperoxidase, ↑interleukin 1 beta and ↑tumor necrosis factor α) and hypoxia (HIF-1α) biomarkers. Peroxynitrite and nitrotyrosine were positively correlated with aldosterone level. Nitrosative stress was also associated with inflammation and HIF-1α. Interestingly, plasma nitrotyrosine and serum MPO differentiated patients with adrenal tumor from healthy individuals with high sensitivity and specificity. Moreover, using multivariate regression analysis, we showed that ONOO^- and IL-1β depended on cortisol level, while ONOO^-, nitrotyrosine and HIF-1α were associated with aldosterone. Unfortunately, none of the assessed biomarkers differentiated between tumor types studied, suggesting that the severity of nitrosative damage and inflammation are similar in patients with incidentaloma, pheochromocytoma, and Cushing's or Conn's adenoma.

Conclusion

Adrenal tumors are associated with increased protein nitration/S-nitrosylation and inflammation.

The Significance of Redox Biomarkers in the Evaluation of the Antioxidant Profile In Vitro and In Vivo

The present Special Issue of Antioxidants, entitled The Significance of Redox Biomarkers in the Evaluation of the Antioxidant Profile In Vitro and In Vivo, ten research articles emphasize the significance of adopting reliable redox biomarkers to determine the antioxidant activities of bioactive compounds in vitro and to assess blood and tissue redox status in vivo [...].

Salivary Biomarkers of Oxidative Stress and Inflammation in Stroke Patients: From Basic Research to Clinical Practice

Cerebral stroke is a serious worldwide health problem, as can be seen by the global epidemic of the disease. In this disorder, when the blood flow is compromised by ruptures or blocked arteries, sudden death of neurons is observed as a result of a lack of oxygen and nutrients. Numerous severe problems and frequent complications also exist in stroke patients; therefore, there is an urgent need to develop new therapeutic, diagnostic, and prognostic methods for the disease. At present, the diagnosis of stroke is based on a neurological examination, medical history, and neuroimaging, due to the fact that rapid and noninvasive diagnostic tests are unavailable. Nevertheless, oxidative stress and inflammation are considered key factors in stroke pathogenesis. Oxygen free radicals are responsible for oxidation of lipids, proteins, and DNA/RNA, which in turn contributes to oxidative damage of the brain. Toxic products of the oxidation reactions act cytostatically on the cell by damaging cell membranes and leading to neuronal death by apoptosis or necrosis. Thus, it seems that redox/inflammatory biomarkers might be used in the diagnosis of the disease. Nowadays, saliva is of increasing interest in clinical laboratory medicine. Redox biomarkers could be obtained easily, noninvasively, cheaply, and stress-free from saliva. This minireview is aimed at presenting the current knowledge concerning the use of salivary biomarkers of oxidative stress and inflammation in the diagnosis and prognosis of stroke.

Salivary Outer Membrane Vesicles and DNA Methylation of Small Extracellular Vesicles as Biomarkers for Periodontal Status: A Pilot Study

Periodontitis is an inflammatory disease, associated with a microbial dysbiosis. Early detection using salivary small extracellular vesicles (sEVs) biomarkers may facilitate timely prevention. sEVs derived from different species (i.e., humans, bacteria) are expected to circulate in saliva. This pilot study recruited 22 participants (seven periodontal healthy, seven gingivitis and eight periodontitis) and salivary sEVs were isolated using the size-exclusion chromatography (SEC) method. The healthy, gingivitis and periodontitis groups were compared in terms of salivary sEVs in the CD9+ sEV subpopulation, Gram-negative bacteria-enriched lipopolysaccharide (LPS+) outer membrane vesicles (OMVs) and global DNA methylation pattern of 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC) and N6-Methyladenosine (m6dA). It was found that LPS+ OMVs, global 5mC methylation and four periodontal pathogens (T. denticola, E. corrodens, P. gingivalis and F. nucleatum) that secreted OMVs were significantly increased in periodontitis sEVs compared to those from healthy groups. These differences were more pronounced in sEVs than the whole saliva and were more superior in distinguishing periodontitis than gingivitis, in comparison to healthy patients. Of note, global 5mC hypermethylation in salivary sEVs can distinguish periodontitis patients from both healthy controls and gingivitis patients with high sensitivity and specificity (AUC = 1). The research findings suggest that assessing global sEV methylation may be a useful biomarker for periodontitis.

Salivary Gland Dysfunction in Patients with Chronic Heart Failure Is Aggravated by Nitrosative Stress, as Well as Oxidation and Glycation of Proteins

Chronic heart failure (HF) is an important clinical, social, and economic problem. A key role in HF progression is played by oxidative stress. Free oxygen radicals, formed under the conditions of hypoxia and reperfusion, participate in myocardial stunning and other forms of post-reperfusion damage. HF patients also suffer from disorders connected with saliva secretion. However, still little is known about the mechanisms that impair the secretory function of salivary glands in these patients. In the presented study, we were the first to compare the antioxidant barrier, protein glycoxidation, and nitrosative/nitrative stress in non-stimulated (non-stimulated whole saliva (NWS)) and stimulated (SWS) saliva of HF patients. The study included 50 HF patients with normal saliva (NS) secretion (n = 27) and hyposalivation (HS) (n = 23), as well as an age- and gender-matched control group (n = 50). We demonstrated that, in NWS of HF patients with HS, the concentration of low-molecular-weight non-enzymatic antioxidants decreased (↓total polyphenols, ↓ascorbic acid, ↓reduced glutathione, ↓albumin) compared to HF patients with normal saliva (NS) secretion, as well as the control group (except albumin). We also observed increased content of protein glycoxidation products (↑dityrosine, ↑kynurenine, ↑glycophore) in NWS and SWS of HF patients with HS compared to healthy controls. Interestingly, the content of dityrosine, N-formylkynurenine, and glycophore in NWS was also significantly higher in HF patients with HS compared to those with NS secretion. The concentration of NO was considerably lower, while the levels of peroxynitrite and nitrotyrosine were significantly higher in NWS and SWS of HF subjects with HS compared to the controls. Salivary gland dysfunction occurs in patients with chronic HF with the submandibular salivary glands being the least efficient. Oxidative/nitrosative stress may be one of the mechanisms responsible for the impairment of salivary gland secretory function in HF patients.

Phloroglucinol Strengthens the Antioxidant Barrier and Reduces Oxidative/Nitrosative Stress in Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is one of the most commonly occurring diseases within western dietary patterns. Usually untreated, it may lead to type 2 diabetes mellitus (T2DM), steatohepatitis (NASH), and hepatocellular carcinoma (HCC). Besides its severe aftermath, up to now, there is no known therapeutic approach to this disease in everyday clinical practice. Most NAFLD patients are encouraged to do physical activities or diet change and remain without pharmacological treatment. In this study, we present phloroglucinol (PHG) as a novel and promising compound in NAFLD treatment. PHG significantly increased the level of enzymatic and nonenzymatic antioxidants both in palmitate and hydrogen peroxide-induced oxidative stress models. Strengthened antioxidative defense reduced the oxidative/nitrosative damage to cell proteins, lipids, and carbohydrates. Furthermore, PHG treatment reduced hepatic steatosis; lowered inflammatory markers, such as NF-κB or HIF-1α; and inhibited cell apoptosis. Moreover, PHG had a more comprehensive effect than other commonly used antioxidants: N-acetylcysteine (NAC) and α-lipoic acid (ALA), suggesting its clinical usability. Therefore, our paper supports the benefits of natural compounds as a therapeutical approach to NAFLD.

The Effect of Selected Dental Materials Used in Conservative Dentistry, Endodontics, Surgery, and Orthodontics as Well as during the Periodontal Treatment on the Redox Balance in the Oral Cavity

Oxidative stress (OS) is a redox homeostasis disorder that results in oxidation of cell components and thus disturbs cell metabolism. OS is induced by numerous internal as well as external factors. According to recent studies, dental treatment may also be one of them. The aim of our work was to assess the effect of dental treatment on the redox balance of the oral cavity. We reviewed literature available in PubMed, Medline, and Scopus databases, including the results from 2010 to 2020. Publications were searched according to the keywords: oxidative stress and dental monomers; oxidative stress and amalgam; oxidative stress and periodontitis, oxidative stress and braces, oxidative stress and titanium; oxidative stress and dental implants, oxidative stress and endodontics treatment, oxidative stress and dental treatment; and oxidative stress and dental composite. It was found that dental treatment with the use of composites, amalgams, glass-ionomers, materials for root canal filling/rinsing, orthodontic braces (made of various metal alloys), titanium implants, or whitening agents can disturb oral redox homeostasis by affecting the antioxidant barrier and increasing oxidative damage to salivary proteins, lipids, and DNA. Abnormal saliva secretion/composition was also observed in dental patients in the course of OS. It is suggested that the addition of antioxidants to dental materials or antioxidant therapy applied during dental treatment could protect the patient against harmful effects of OS in the oral cavity.

Bariatric Surgery Normalizes Protein Glycoxidation and Nitrosative Stress in Morbidly Obese Patients

The results of recent studies indicate the key role of nitrosative stress and protein oxidative damage in the development of morbid obesity. Nevertheless, the effect of bariatric surgery on protein oxidation/glycation and nitrosative/nitrative stress is not yet known. This is the first study evaluating protein glycoxidation and protein nitrosative damage in morbidly obese patients before and after (one, three, six and twelve months) laparoscopic sleeve gastrectomy. The study included 50 women with morbid obesity as well as 50 age- and gender-matched healthy controls. We demonstrated significant increases in serum myeloperoxidase, plasma glycooxidative products (dityrosine, kynurenine, N-formyl-kynurenine, amyloid, Amadori products, glycophore), protein oxidative damage (ischemia modified albumin) and nitrosative/nitrative stress (nitric oxide, peroxy-nitrite, S-nitrosothiols and nitro-tyrosine) in morbidly obese subjects as compared to lean controls, whereas plasma tryptophan and total thiols were statistically decreased. Bariatric surgery generally reduces the abnormalities in the glycoxidation of proteins and nitrosative/nitrative stress. Noteworthily, in the patients with metabolic syndrome (MS+), we showed no differences in most redox biomarkers, as compared to morbidly obese patients without MS (MS−). However, two markers: were able to differentiate MS+ and MS− with high specificity and sensitivity: peroxy-nitrite (>70%) and S-nitrosothiols (>60%). Further studies are required to confirm the diagnostic usefulness of such biomarkers.

Salivary Redox Biomarkers in the Course of Caries and Periodontal Disease

Caries are a pathological process of extracorporeal nature, characterized by demineralization of inorganic substances as well as proteolysis triggered by acids produced by bacteria present in dental plaque, as a result of metabolism of sugars of both external and internal origin. Periodontal disease, on the other hand, is a multifactorial degenerative disease associated with inflammation, involving a group of tissues that surround the dental cervix and root of the tooth. It is believed that one of the mechanisms in the etiopathogenesis of caries and periodontitis are disorders of local and/or general oxidative stress (OS) parameters. Numerous clinical studies have confirmed the relationship between oxidative stress markers and oral diseases. In most analyzed studies, technical and biological variability was so high that none of the markers so far has proven suitable for routine clinical use. The aim of systematic reviews of the literature is to present the existing studies on OS parameters, mainly concerning the activity of antioxidant enzymes in saliva of patients with caries and periodontitis.

Gingival Crevicular Fluid Peptidome Profiling in Healthy and in Periodontal Diseases

Given its intrinsic nature, gingival crevicular fluid (GCF) is an attractive source for the discovery of novel biomarkers of periodontal diseases. GCF contains antimicrobial peptides and small proteins which could play a role in specific immune-inflammatory responses to guarantee healthy gingival status and to prevent periodontal diseases. Presently, several proteomics studies have been performed leading to increased coverage of the GCF proteome, however fewer efforts have been done to explore its natural peptides. To fill such gap, this review provides an overview of the mass spectrometric platforms and experimental designs aimed at GCF peptidome profiling, including our own data and experiences gathered from over several years of matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) based approach in this field. These tools might be useful for capturing snapshots containing diagnostic clinical information on an individual and population scale, which may be used as a specific code not only for the diagnosis of the nature or the stage of the inflammatory process in periodontal disease, but more importantly, for its prognosis, which is still an unmet medical need. As a matter of fact, current peptidomics investigations suffer from a lack of standardized procedures, posing a serious problem for data interpretation. Descriptions of the efforts to address such concerns will be highlighted.

Comprehensive Evaluation of the Oral Health Status, Salivary Gland Function, and Oxidative Stress in the Saliva of Patients with Subacute Phase of Stroke: A Case-Control Study

This is the first study to assess, comprehensively, the oral health status; salivary glands’ function and enzymatic and non-enzymatic antioxidant defense; and oxidative damage to proteins and lipids in the non-stimulated (NWS) and stimulated (SWS) whole saliva of stroke patients. The study included 30 patients in the subacute phase of the stroke and an age and gender-matched control group. We showed that the activity of antioxidant enzymes (catalase and salivary peroxidase) was significantly higher in both NWS and SWS of stroke patients, similarly to uric acid concentration. However, in the study group, the reduced glutathione (GSH) concentration in SWS decreased. The contents of protein glycooxidation products (advanced glycation end products (AGE) and protein oxidation products (AOPP)) and lipid hydroperoxides were significantly higher in NWS and SWS of stroke patients. In the study group there was also a decrease in stimulated saliva secretion and total protein content. Interestingly, products of protein and lipid oxidation correlate negatively with SWS flow. The ROC analysis showed that salivary GSH with 100% specificity and 100% sensitivity differentiates the analyzed groups (AUC = 1.0). To sum up, in subacute stroke patients there are redox imbalances and oxidative damage to proteins and lipids in non-stimulated and stimulated saliva. Stroke patients also suffer from salivary gland dysfunction.

Enhanced Salivary and General Oxidative Stress in Hashimoto's Thyroiditis Women in Euthyreosis

Hashimoto’s thyroiditis (HT) is one of the most common autoimmune diseases. Although HT is inextricably linked to oxidative stress, there have been no studies assessing salivary redox homeostasis or salivary gland function in patients with HT. This study is the first to compare antioxidant defense and oxidative stress biomarkers in non-stimulated (NWS) and stimulated (SWS) whole saliva and plasma/erythrocytes of HT patients compared to controls. The study included 45 women with HT in the euthyreosis period as well as an age- and gender-matched control group. We showed that NWS secretion was significantly lower in HT patients compared to healthy controls, similar to salivary amylase activity in NWS and SWS. Catalase and peroxidase activities were considerably higher in NWS and SWS of HT patients, while the concentrations of reduced glutathione and uric acid were significantly lower in comparison with healthy subjects. Total antioxidant potential was significantly lower, while total oxidant status and the level of oxidation products of proteins (advanced glycation end products, advanced oxidation protein products) and lipids (malondialdehyde, lipid hydroperoxides) were significantly higher in NWS, SWS and plasma of HT patients. In conclusion, in both salivary glands of women with HT in euthyreosis, the ability to maintain redox homeostasis was hindered. In HT patients we observed oxidative damage to salivary proteins and lipids; thus, some biomarkers of oxidative stress may present a potential diagnostic value.

Total Oxidant and Antioxidant Capacity of Gingival Crevicular Fluid and Saliva in Patients with Periodontitis: Review and Clinical Study

Periodontitis is inextricably linked to oxidative-reductive (redox) imbalance. However, little is still known about the resultant ability to scavenge oxygen free radicals in saliva and gingival crevicular fluid in patients with periodontitis. The multitude of enzymatic and non-enzymatic antioxidants and their synergistic effects cause an interest in the evaluation of the total antioxidative capacity. Thus, our study aimed to evaluate the total oxidative and antioxidative activity of gingival crevicular fluid and saliva in the periodontitis, as well as to relate these biomarkers to clinical indices of periodontopathy. Additionally, by calculating the oxidative stress index (OSI), the intensity of redox disturbances was also evaluated. Fifty-eight periodontitis patients were included in the study and divided into two subgroups depending on the severity of the disease. In the non-stimulated/stimulated saliva as well as a gingival crevicular fluid of the study group, we found significantly higher OSI and total oxidant status (TOS) as well as lower total antioxidant capacity (TAC). However, the ability to reduce iron ions (FRAP) was significantly lower only in stimulated and non-stimulated saliva of patients with periodontitis. The examined parameters correlated with the periodontium’s clinical condition, which indicates the exacerbation of the inflammatory process. However, TAC, TOS, OSI, and FRAP did not differentiate individual stages of periodontitis.