Eight-Week Consumption of High-Sucrose Diet Has a Pro-Oxidant Effect and Alters the Function of the Salivary Glands of Rats

Assessment of the toxic effects of levetiracetam on biochemical, functional, and redox parameters of salivary glands in male Wistar rats

Levetiracetam (LEV) is an anticonvulsant for epilepsy. The toxic effects of this medication in tissues have been associated with redox state imbalance, which can lead to salivary gland dysfunction. Therefore, the current work investigated the effects of LEV on the biochemical, functional, and redox parameters of the parotid and submandibular glands in rats. For this, male Wistar rats (Rattus norvegicus albinus) were randomly divided into 3 groups (n = 10/group): Control (0.9% saline solution), LEV100 (100 mg/kg), and LEV300 (300 mg/kg). After 21 consecutive days of intragastric gavage treatments, pilocarpine stimulated saliva secretion was collected for salivary biochemical analysis. The extracted salivary glands were utilized for histomorphometry and redox state analyses. Our results showed that LEV300 increased plasma hepatotoxicity markers and reduced salivary amylase activity and the acinar surface area of the parotid gland. Total oxidant capacity and oxidative damage to lipids and proteins were higher in the parotid gland, while total antioxidant capacity and uric acid levels were reduced in the submandibular gland of the LEV100 group compared to Control. On the other hand, total oxidant capacity, oxidative damage to lipids and proteins, total antioxidant capacity, and uric acid levels were lower in both salivary glands of the LEV300 group compared to Control. Superoxide dismutase and glutathione peroxidase activities were lower in the salivary glands of treated animals compared to Control. In conclusion our data suggest that treatment with LEV represents a potentially toxic agent, that contributes to drug-induced salivary gland dysfunction.

Mitochondrial Redox Balance of Fibroblasts Exposed to Ti-6Al-4V Microplates Subjected to Different Types of Anodizing

Despite the high biocompatibility of titanium and its alloys, the need to remove titanium implants is increasingly being debated due to the potential for adverse effects associated with long-term retention. Therefore, new solutions are being sought to enhance the biocompatibility of titanium implants. One of them is to increase the thickness of the passive layer of the implant made of titanium dioxide. We were the first to evaluate the effect of hard-anodized (type II) Ti-6Al-4V alloy discs on the cytotoxicity, mitochondrial function, and redox balance of fibroblasts mitochondria compared to standard-anodized (type III) and non-anodized discs. The study used fibroblasts obtained from human gingival tissue. The test discs were applied to the bottom of 12-well plates. Cells were cultured for 24 h and 7, 14, and 21 days and mitochondria were isolated. We demonstrated the occurrence of oxidative stress in the mitochondria of fibroblasts of all tested groups, regardless of the presence and type of anodization. Type II anodization prevented changes in complex II activity (vs. control). The lowest degree of citrate synthase inhibition occurred in mitochondria exposed to titanium discs with type II anodization. In the last phase of culture, the presence of type II anodization reduced the degree of cytochrome c oxidase inhibition compared to the other tests groups and the control group, and prevented apoptosis. Throughout the experiment, the release of titanium, aluminium, and vanadium ions from titanium discs with a hard-anodized passive layer was higher than from the other titanium discs, but decreased with time. The obtained results proved the existence of dysfunction and redox imbalance in the mitochondria of fibroblasts exposed to hard-anodized titanium discs, suggesting the need to search for new materials perhaps biodegradable in tissues of the human body.

Iron supplementation does not aggravate impaired glucose tolerance and sugar overload-induced genotoxicity in rats

High sugar intake is a major risk factor for metabolic disorders. Genotoxicity is an important factor in diabetes onset, and iron (Fe) may be an aggravating element. However, this relationship is still poorly established. Thus, this study evaluated whether Fe supplementation could aggravate obesity, impaired glucose tolerance, and sugar overload-induced genotoxicity in rats. A total of 24 rats were treated with different diets: standard diet (SD, n = 8), invert sugar overload (320 g/L, HSD, n = 8), or Fe plus invert sugar overload (2.56 mg/L of Fe²⁺, Fe-HSD, n = 8) for four months. After treatment, the Fe-HSD group showed no excessive weight gain or impaired glucose tolerance. DNA damage in blood, as assessed by comet assay, gradually increased in HSD during treatment (p < 0.001), whereas Fe-HSD showed a nonlinear increase in DNA damage. Moreover, Fe-HSD presented 0.6-fold more DNA damage compared with SD (p = 0.0055) in the 1st month of treatment. At months 2 and 3, results show a ≥ 1.4-fold increase in HSD and Fe-HSD DNA damage, respectively, compared with SD (p < 0.01). At the end of the experiment, only HSD DNA damage differed from SD (1.5-fold more, p = 0.0196). Fe supplementation did not aggravate the invert sugar-induced DNA damage (p > 0.05). In the pancreas, results showed no differences in DNA damage. Mutagenicity, evaluated by micronucleus testing, was not observed regardless of treatment (p = 0.428). Fe supplementation, in the evaluated concentration, did not aggravate weight gain, impaired glucose tolerance, and sugar overload-induced genotoxicity in rats.

Assessment of redox state and biochemical parameters of salivary glands in rats treated with anti-obesity drug sibutramine hydrochloride

OBJECTIVES

To investigate the effects of anti-obesity drug sibutramine hydrochloride (SB) on redox state and biochemical parameters in the salivary glands.

MATERIALS AND METHODS

Adult male Wistar rats were randomly divided into the following groups (n = 8 per group): control rats treated with vehicle (C) and rats treated with SB (10 mg/kg/day) by intragastric gavage for 28 days. The parotid (PG) and submandibular (SMG) glands were processed using histomorphometric analysis, and total protein, amylase, mucin, and oxidative damage to lipids were determined by measuring the formation of thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), uric acid (UA), total glutathione (tGSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and AKT phosphorylation.

RESULTS

SB decreased the acinar area, and increased the stromal area in PG, while no effect on the morphometric parameters was observed in SMG. SB also increased oxidative damage to lipids (TBARs). The SB group showed lower total protein, amylase, TAC, UA, tGSH, SOD, CAT, and GPx than the C group in PG, while in SMG, SB decreased total protein, mucin, tGSH, SOD, CAT, and GPx. However, increased AKT phosphorylation observed in both salivary glands suggests that SB exerts low-intensity oxidative stress.

CONCLUSIONS

SB impaired enzymatic and non-enzymatic antioxidant defenses in the salivary glands of rats.

CLINICAL RELEVANCE

Chronic treatment with SB could mitigate salivary gland dysfunction due to disturbance of redox state.

Quantitative Scintigraphy Evaluated the Relationship between 131I Therapy and Salivary Glands Function in DTC Patients: A Retrospective Analysis

Purpose

Quantitative scintigraphy to evaluate salivary gland function changes in patients with differentiated thyroid cancer (DTC) after iodine-131 (¹³¹I) treatment.

Methods

A total of 458 patients with DTC grouped by sex and age were included. Salivary gland scintigraphy was performed to evaluate salivary gland function before and after ¹³¹I treatment. The uptake fraction (UF), uptake index (UI), and excretion fraction (EF) of two pairs of parotid glands and submandibular glands were measured and compared. The Chi-square test was conducted according to function impairment count.

Results

Salivary gland function in different age groups and sexes were quite different, especially for women <55 years old, who had decreased UF, UI, and EF of all four glands without basal injury. The secretion or uptake function of some salivary glands with basic function impairment before ¹³¹I treatment was increased after iodine treatment. Only a small percentage of males showed reduced functional parameters after several treatments. The most significant difference in the count of impairment for the four salivary glands were the first and third examinations, which was more evident in women. The submandibular gland had the most significant reduction in uptake.

Conclusion

Changes in salivary gland function are more common in young females being treated for DTC. Impairment of salivary gland function is correlated with the number of treatments and the cumulative dose of ¹³¹I. Some salivary gland functions impaired before ¹³¹I treatment were enhanced in the early treatment.

Effects of orchiectomy and testosterone replacement therapy on redox balance and salivary gland function in Wistar rats

The objective of this study was to investigate the effects of orchiectomy (ORX) and testosterone replacement therapy (TRT) on redox balance and function of salivary glands. Forty-five young adult male Wistar rats (3 months old) were either castrated bilaterally or underwent fictitious surgery (SHAM) and were subsequently distributed into 3 groups: SHAM, ORX, and TRT (castrated rats that received an intramuscular injection of testosterone cypionate 10 mg/kg/weekly). All treatments started 4 weeks after castration (4 months old) and lasted 4 weeks (5 months old). At the end of treatment, pilocarpine-induced salivary secretion was collected to analyze salivary flow rate and biochemistry composition, and the parotid (PG) and submandibular (SMG) glands were sampled for redox balance markers and histomorphometric analyses. ORX increased salivary flow rate, calcium, phosphate, and chloride, and decreased total protein and amylase, while not changing the salivary buffer capacity, pH, sodium, and potassium compared to SHAM. TRT restored all salivary parameters to SHAM values. ORX increased oxidative lipid and protein damage, total antioxidant capacity, and uric acid in both salivary glands compared to SHAM. Superoxide dismutase, catalase, and glutathione peroxidase activities were greater only in the SMG of the ORX group in relation to SHAM. ORX decreased duct and acini area, while increasing connective tissue in the PG. On the other hand, ORX reduced duct area and increased acini area in the SMG compared to SHAM. TRT restored the redox balance and histomorphometric parameters to close to SHAM values in both salivary glands. Orchiectomy-induced salivary gland dysfunction was characterized by an increase in the salivary flow rate and changes in the secretion of total protein, amylase, and electrolytes, which are key factors, considered important for maintaining oral health status. To sum up, orchiectomy impaired the redox balance of the salivary glands. Our results also showed that TRT reversed the oxidative damage, morphological alterations, and salivary gland dysfunction induced by orchiectomy. Therefore, these results suggest an important action of testosterone on the redox balance and secretory ability of salivary glands.

Human dental pulp stem cells attenuate streptozotocin-induced parotid gland injury in rats

OBJECTIVE

Diabetes mellitus causes deterioration in the body, including serious damage of the oral cavity related to salivary gland dysfunction, characterised by hyposalivation and xerostomia. Human dental pulp stem cells (hDPSCs) represent a promising therapy source, due to the easy, minimally invasive surgical access to these cells and their high proliferative capacity. It was previously reported that the trophic support mediated by these cells can rescue the functional and structural alterations of damaged salivary glands. However, potential differentiation and paracrine effects of hDPSCs in diabetic-induced parotid gland damage have not been investigated. Our study aimed to investigate the therapeutic effects of intravenous transplantation of hDPSCs on parotid gland injury in a rat model of streptozotocin (STZ)-induced type 1 diabetes.

METHODS

Thirty Sprague-Dawley male rats were randomly categorised into three groups: control, diabetic (STZ), and transplanted (STZ + hDPSCs). The hDPSCs or the vehicles were injected into the rats' tail veins, 7 days after STZ injection. Fasting blood glucose levels were monitored weekly. A glucose tolerance test was performed, and the parotid gland weight, salivary flow rate, oxidative stress indices, parotid gland histology, and caspase-3, vascular endothelial growth factor, proliferating cell nuclear antigen, neuronal nitric oxide synthase, endothelial nitric oxide synthase, and tetrahydrobiopterin biosynthetic enzyme expression levels in parotid tissues were assessed 28 days post-transplantation.

RESULTS

Transplantation of hDPSCs decreased blood glucose, improved parotid gland weight and salivary flow rate, and reduced oxidative stress. The cells migrated to the STZ-injured parotid gland and differentiated into acinar, ductal, and myoepithelial cells. Moreover, hDPSCs downregulated the expression of caspase-3 and upregulated the expression of vascular endothelial growth factor and proliferating cell nuclear antigen, likely exerting pro-angiogenic and anti-apoptotic effects and promoting endogenous regeneration. In addition, the transplanted cells enhanced the parotid nitric oxide-tetrahydrobiopterin pathway.

CONCLUSIONS

Our results showed that hDPSCs migrated to and survived within the STZ-injured parotid gland, where functional and morphological damage was prevented due to the restoration of normal glucose levels, differentiation into parotid cell populations, and stimulation of paracrine-mediated regeneration. Thus, hDPSCs may have potential in the treatment of diabetes-induced parotid gland injury.

N-acetylcysteine supplementation did not reverse mitochondrial oxidative stress, apoptosis, and inflammation in the salivary glands of hyperglycemic rats

Background/objectives

Previous studies have shown that N-acetylcysteine (NAC) supplementation with the simultaneous inclusion of HFD prevents salivary glands from oxidative stress and mitochondrial dysfunction. In this experiment, we examined if NAC supplementation could reverse the harmful effect of HFD on mitochondrial function, reduce the severity of apoptosis, and the activity of pro-oxidative enzymes in the salivary glands of rats with confirmed hyperglycemia.

Subjects/methods

Wistar rats were fed the standard or high-fat (HFD) diet for 10 weeks. After 6 weeks of the experiment, HFD rats were diagnosed with hyperglycemia and for the next 4 weeks, the animals were given NAC intragastrically. In the mitochondrial fraction of the parotid (PG) and submandibular salivary glands (SMG), we assessed redox status, inflammation, and apoptosis.

Results

The inclusion of NAC increased the activity of mitochondrial complexes I and II + III as well as decreased the concentration of interleukin-1β, tumor necrosis factor α, and caspase-3, but only in the parotid glands of rats with hyperglycemia compared to the HFD group. However, N-acetylcysteine supplementation did not reduce the activity of caspase-9 or the Bax/Bcl-2 ratio in PG and SMG mitochondria. In both salivary glands we observed reduced activity of cytochrome c oxidase, NADPH oxidase, and xanthine oxidase, as well as hindered production of ROS and lower ADP/ATP radio, but the levels of these parameters were not comparable to the control group.

Conclusions

We demonstrated that NAC supplementation restores the glutathione ratio only in the mitochondria of the submandibular salivary glands. The supply of NAC did not significantly affect the other measured parameters. Our results indicate that NAC supplementation provides little protection against free radicals, apoptosis, and inflammation in the salivary gland mitochondria of HFD rats. Stimulated salivary secretion in hyperglycaemic rats supplemented with NAC seems to be closely related to mitochondrial respiratory capacity and appropriate ATP level.

Electromagnetic Fields Modify Redox Balance in the Rat Gastrointestinal Tract

Objective: The aim of the study was to assess the influence of electromagnetic fields with divergent physical properties on the prooxidative and antioxidative balances in homogenates of the tongue, salivary glands, esophagus, stomach, and small and large intestines of rats.

Material and Methods: Forty rats were randomly divided into four equal groups, namely, a control group, a group exposed to low-frequency electromagnetic fields (LF-EMFs; frequency: 50 Hz; intensity: 10 kV/m; magnetic induction: 4.3 pT), a group exposed to radiofrequency electromagnetic fields (RF-EMFs) emitted by mobile phones (frequency: 900 MHz), and a group exposed simultaneously to LF-EMFs and RF-EMFs emitted by mobile phones. After 28 consecutive days of the experiment, the following pro- and antioxidative markers were assessed in the gastrointestinal tract homogenates: superoxide dismutase (SOD) and its two isoenzymes (Mn-SOD, Cu,Zn-SOD) catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), total antioxidative capacity (TAC), total oxidative status (TOS), and malondialdehyde (MDA).

Results: In rats exposed to LF-EMFs, higher concentrations of the markers of prooxidant processes, MDA or TOS, were observed in the salivary glands, esophagus, and small intestine homogenates in comparison with the control group. Additionally, in the group of rats opposite to the control, antioxidant activity was observed. The main differences included a higher activity of Cu,Zn-SOD in homogenates of the tongue, salivary glands, and esophagus as well as decreased activity of CAT in homogenates of the tongue, esophagus, and small intestine. In animals exposed to RF-EMFs, the concentration of TOS was higher in the large intestine than in control rats. The main difference of antioxidant activity was presented by decreased Cu,Zn-SOD in homogenates of the salivary glands, stomach, small and large intestine as well as CAT in homogenates of the tongue, esophagus, stomach, and small and large intestine. Moreover, in rats exposed simultaneously to LF-EMFs and RF-EMFs, a lower concentration of TOS was observed. Antioxidant activity was presented by a decreased activity of CAT in homogenates of the tongue, esophagus, stomach, and small and large intestine in comparison to the control group.

Conclusion: Among those applied in the study, electromagnetic fields of a low-frequency caused the most significant disturbances of oxidative stress in the rat gastrointestinal tract.

Salivary Redox Biomarkers in Insulin Resistance: Preclinical Studies in an Animal Model

Insulin resistance (IR) is a condition of impaired tissue response to insulin. Although there are many methods to diagnose IR, new biomarkers are still being sought for early and noninvasive diagnosis of the disease. Of particular interest in laboratory diagnostics is saliva collected in a stress-free, noninvasive, and straightforward manner. The purpose of the study was to evaluate the diagnostic utility of salivary redox biomarkers in preclinical studies in an animal model. The study was conducted on 20 male Wistar rats divided into two equal groups: a standard diet and a high-fat diet (HFD). In all rats fed the HFD, IR was confirmed by an elevated homeostasis model assessment (HOMA-IR) index. We have shown that IR is responsible for the depletion of the enzymatic (↓superoxide dismutase) and nonenzymatic (↓ascorbic acid, ↓reduced glutathione (GSH)) antioxidant barrier at both the central (serum/plasma) and salivary gland (saliva) levels. In IR rats, we also demonstrated significantly higher concentrations of protein/lipid oxidation (↑protein carbonyls, ↑4-hydroxynoneal (4-HNE)), glycation (↑advanced glycation end products), and nitration (↑3-nitrotyrosine) products in both saliva and blood plasma. Salivary nonenzymatic antioxidants and oxidative stress products generally correlate with their blood levels, while GSH and 4-HNE have the highest correlation coefficient. Salivary GSH and 4-HNE correlate with body weight and BMI and indices of carbohydrate metabolism (glucose, insulin, HOMA-IR) and proinflammatory adipokines (leptin, resistin, TNF-α). These biomarkers differentiate IR from healthy controls with very high sensitivity (100%) and specificity (100%). The high diagnostic utility of salivary GSH and 4-HNE is also confirmed by multivariate regression analysis. Summarizing, saliva can be used to assess the systemic antioxidant status and the intensity of systemic oxidative stress. Salivary GSH and 4-HNE may be potential biomarkers of IR progression. There is a need for human clinical trials to evaluate the diagnostic utility of salivary redox biomarkers in IR conditions.

Effects of different models of sucrose intake on the oxidative status of the uterus and ovary of rats

The aim of the study was to assess the effect of different models of sucrose intake on carbohydrate-lipid metabolism and changes in oxidant balance in the ovaries and uterus of rats. Animals were divided into three groups: I—basic feed, II—feed contains 8% of sucrose, III—alternately every second week the basic feed and modified feed contains 16% of sucrose. The diet containing 8% of sucrose was found to result in an increased activity of antioxidant enzymes in the blood, with unchanged malonylodialdehyde concentration. Variable sucrose administration pattern intensified oxidative stress in the blood and led to disturbed redox equilibrium in the rat uterus, even at a comparable long-term sucrose uptake as in the group II. This was manifested as a reduced superoxide dismutase activity (in the blood and uterus) and a higher malonylodialdehyde concentration (in the uterus). The changes observed could have been a result of metabolic disorders (higher amount of visceral fat, higher glucose concentration, higher index of homeostasis model assessment of insulin resistance, and reduced HDL-cholesterol concentration) and endocrine disorders (higher oestrogen concentrations). Changes in the antioxidant status in the rats kept on the alternating diet, may underpin the failure of fertilised egg implantation in the uterine tissue and pregnancy completion.

Gemigliptin suppresses salivary dysfunction in streptozotocin-induced diabetic rats

Patients with diabetes commonly experience hyposalivation, which induces discomfort in eating, swallowing, dryness, smell, and speaking, as well as increases the incidence of periodontal disease. Dipeptidyl peptidase-4 (DPP4) inhibitors are frequently used as antidiabetic drugs that lower glucose levels by utilizing similar mechanisms; however, additional protective functions of each gliptin have been discovered. In this study, the protective roles of gemigliptin, a DPP4 inhibitor, against salivary dysfunction under diabetic conditions were investigated. Streptozotocin-induced diabetic rats received gemigliptin 10 mg/kg or 100 mg/kg via oral gavage for 3 weeks. The weights of salivary gland tissues, saliva secretion, and antioxidant capacity in salivary glands were reduced after diabetes induction, but were significantly preserved following gemigliptin treatment. In salivary gland analysis, expression of apoptotic proteins, as well as amylase and aquaporin-5 (AQP5) protein expression, were increased following gemigliptin treatment. Furthermore, the number of TUNEL-positive cells decreased after gemigliptin treatment. Therefore, gemigliptin has protective roles against salivary dysfunction observed in diabetes, mediated via antioxidant, anti-apoptotic, and salivary secretion mechanisms. These results may help in selecting a suitable drug for patients with diabetes experiencing salivary dysfunction.

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.

Pleiotropic Properties of Valsartan: Do They Result from the Antiglycooxidant Activity? Literature Review and In Vitro Study

Valsartan belongs to angiotensin II type 1 (AT1) receptor blockers (ARB) used in cardiovascular diseases like heart failure and hypertension. Except for its AT1-antagonism, another mechanism of drug action has been suggested in recent research. One of the supposed actions refers to the positive impact on redox balance and reducing protein glycation. Our study is aimed at assessing the antiglycooxidant properties of valsartan in an in vitro model of oxidized bovine serum albumin (BSA). Glucose, fructose, ribose, glyoxal (GO), methylglyoxal (MGO), and chloramine T were used as glycation or oxidation agents. Protein oxidation products (total thiols, protein carbonyls (PC), and advanced oxidation protein products (AOPP)), glycooxidation products (tryptophan, kynurenine, N-formylkynurenine, and dityrosine), glycation products (amyloid-β structure, fructosamine, and advanced glycation end products (AGE)), and albumin antioxidant activity (total antioxidant capacity (TAC), DPPH assay, and ferric reducing antioxidant power (FRAP)) were measured in each sample. In the presence of valsartan, concentrations of protein oxidation and glycation products were significantly lower comparing to control. Moreover, albumin antioxidant activity was significantly higher in those samples. The drug's action was comparable to renowned antiglycation agents and antioxidants, e.g., aminoguanidine, metformin, Trolox, N-acetylcysteine, or alpha-lipoic acid. The conducted experiment proves that valsartan can ameliorate protein glycation and oxidation in vitro in various conditions. Available animal and clinical studies uphold this statement, but further research is needed to confirm it, as reduction of protein oxidation and glycation may prevent cardiovascular disease development.

Salivary Gland Dysfunction in Stroke Patients Is Associated with Increased Protein Glycoxidation and Nitrosative Stress

Stroke is one of the leading causes of disability and death worldwide. Despite intensive medical care, many of the complaints directly threatening the patient's life marginalize their dental needs after the stroke. Recent studies indicate reduced saliva secretion in stroke patients in addition to the increased incidence of caries and periodontal disease. Since oxidative stress plays a vital role in the pathogenesis of salivary gland hypofunction and neurodegenerative disorders (including stroke), this is the first to evaluate the relationship between salivary gland activity and protein glycoxidation and nitrosative damage. The content of glycation and protein oxidation products and nitrosative stress was assessed in nonstimulated (NWS) and stimulated (SWS) whole saliva of stroke patients with normal salivary secretion and hyposalivation (reduced saliva production). The study included 30 patients in the stroke's subacute phase and 30 healthy controls matched by age and sex. We have shown that stroke patients with hyposalivation show increased contents of protein glycation (↑Amadori products and ↑advanced glycation end products), glycoxidation (↑dityrosine), and nitration (↑nitrotyrosine) products compared to stroke cases with normal salivary secretion and control group. Interestingly, higher oxidative/nitrosative stress was found in NWS, which strongly correlates with salivary flow rate, total protein content, and salivary amylase activity. Such relationships were not observed in the control group. Summarizing, oxidative and nitrosative stress may be one of the mechanisms responsible for the impairment of saliva secretion in stroke patients. However, extraglandular sources of salivary oxidative stress in stroke patients cannot be excluded. Further studies to assess salivary gland hypofunction in stroke cases are necessary.

[Features of free radical processes in the liver of rats with a nutrient imbalance]

The activity of free radical processes in liver mitochondria was investigated in rats kept on high-sucrose and low protein/high-sucrose diets. Excess of dietary sucrose caused intensification of free radical processes in liver mitochondria as evidenced by increased hydroxyl radical generation, accumulation of primary (conjugated dienes, ketodienes) and secondary products (TBA-reactive products) of lipid peroxidation, increased cholesterol/phospholipids ratio and also accumulation of oxidative modification products of proteins (carbonyl derivatives). Additional nutritional protein deficiency (low protein/high-sucrose diet) enhanced destructive changes in liver mitochondria. This suggests a critical role of nutrient protein supplementation for maintaining the functional activity of mitochondria. The established changes can be considered as one of possible mechanisms of functional liver activity violation in conditions of nutrient imbalance.

High-Sugar Diet Disrupts Hypothalamic but Not Cerebral Cortex Redox Homeostasis

Despite several reports on the relationship between metabolic and neurodegenerative diseases, the effect of a high-sugar diet (HSD) on brain function is still unknown. Given the crucial role of oxidative stress in the pathogenesis of these disorders, this study was the first to compare the effect of an HSD on the activity of prooxidative enzymes, enzymatic and non-enzymatic antioxidants, and protein oxidative damage in the brain structures regulating energy metabolism (hypothalamus) and cognitive functions (cerebral cortex). Male Wistar rats were randomly divided into two groups (n = 10)-control diet (CD) and high-sugar diet (HSD)-for 8 weeks. We showed a decrease in glutathione peroxidase and superoxide dismutase activity and an increase in catalase activity in the hypothalamus of HSD rats compared to controls. The activity of xanthine oxidase and NADPH oxidase and the contents of oxidation (protein carbonyls), glycoxidation (dityrosine, kynurenine and N-formylkynurenine) and protein glycation products (advanced glycation end products and Amadori products) were significantly higher only in the hypothalamus of the study group. The HSD was also responsible for the disruption of antioxidant systems and oxidative damage to blood proteins, but we did not show any correlation between systemic redox homeostasis and the brain levels. In summary, HSD is responsible for disorders of enzymatic antioxidant defenses only at the central (plasma/serum) and hypothalamic levels but does not affect the cerebral cortex. The hypothalamus is much more sensitive to oxidative damage caused by an HSD than the cerebral cortex.

Centella asiatica alleviates diabetes-induced changes in fatty acid profile and oxidative damage in rat testis

The in vivo effects of Centella asiatica L. Urban (Family: Apiaceae; CA) on diabetes-induced testicular fatty acid misdistribution and oxidative injury were investigated. Diabetic rats were treated with vehicle, CA or metformin daily for 14 days by oral gavage. Fatty acid (FA) content in testis was analysed using gas chromatography-flame ionisation detection while redox indices were measured as peroxide value (PV), malondialdehyde (MDA), oxygen radical antioxidant capacity (ORAC), reduced glutathione (GSH), glutathione S-transferase (GST) and glutathione peroxidase (GPx) activities. Diabetes increased omega-6 (61%), and decreased omega-3 (23%) and monounsaturated fatty acids (MUFA; 18%) compared to non-diabetic controls. Oxidative injury in diabetic rats was confirmed by increases in PV (112%) and MDA (77%) in addition to decreases in GSH (41%) and activities of GST (19%) & GPx (24%) compared to non-diabetic controls. CA treatment led to 17% reduction in omega-6 and 33% rise in MUFA compared to diabetic controls. Additionally, CA ameliorated the oxidative injury and improved antioxidant capacity by increasing GSH (49%), GST (16%) and GPx (23%) when compared to diabetic controls. Data suggest CA potential in alleviating the alterations caused by diabetes in testes through effects on omega-6 and MUFA; and via increased GSH level and dependent enzyme activities.

Effect of vitamin C and E on oxidative stress and antioxidant system in the salivary glands of STZ-induced diabetic rats

OBJECTIVE

We examined the effects of vitamin C and E supplementation in the prevention of oxidative stress in the salivary glands of STZ-induced diabetic rats.

DESIGN

Forty-eight male Wistar rats were divided into six groups (n = 8 in each): control (C), control supplemented with vitamin C (Cvc) and E (Cve), diabetic (D), and diabetic supplemented with vitamin C (Dvc) and E (Dve). Vitamin C (150 mg/kg) and E (300 mg/kg) were daily administered for 21 days. Serum ascorbic acid and α-tocopherol levels were quantified. Glandular levels of hydrogen peroxide (H₂O₂), superoxide anion (O₂^-), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), malondialdehyde (MDA) and the total antioxidant status (TAS) were estimated.

RESULTS

Vitamin C and E levels were reduced in D group. Vitamin C decreased the levels of O₂^- in the salivary gland of diabetic rats. Vitamin E increased the concentration of O₂^- in PA gland of diabetic animals. In the SM gland of the diabetic group, MDA, SOD, GPx and TAS increased. Dve presented reduced SOD activity and increased GR, GPx, and MDA. Dve increased GPx, Gr and TAS levels. In the PA gland, MDA, SOD, CAT, GPx, GR, and TAS were similar in C and D. TAS, SOD, CAT, GPx, and GR increased in Dvc. Vitamin E supplementation resulted in increased MDA and CAT levels and reduced SOD activity.

CONCLUSION

In the SM glands of the diabetic rats, vitamin C supplementation improved the antioxidant system, while vitamin E acted as pro-oxidant.

Salivary Gland Dysfunction, Protein Glycooxidation and Nitrosative Stress in Children with Chronic Kidney Disease

This study is the first to evaluate protein glycooxidation products, lipid oxidative damage and nitrosative stress in non-stimulated (NWS) and stimulated whole saliva (SWS) of children with chronic kidney disease (CKD) divided into two subgroups: normal salivary secretion (n = 18) and hyposalivation (NWS flow < 0.2 mL min-1; n = 12). Hyposalivation was observed in all patients with severe renal failure (4-5 stage CKD), while saliva secretion > 0.2 mL/min in children with mild-moderate CKD (1-3 stage) and controls. Salivary amylase activity and total protein content were significantly lower in CKD children with hyposalivation compared to CKD patients with normal saliva secretion and control group. The fluorescence of protein glycooxidation products (kynurenine, N-formylkynurenine, advanced glycation end products), the content of oxidative damage to lipids (4-hydroxynonneal, 8-isoprostanes) and nitrosative stress (peroxynitrite, nitrotyrosine) were significantly higher in NWS, SWS, and plasma of CKD children with hyposalivation compared to patients with normal salivary secretion and healthy controls. In CKD group, salivary oxidation products correlated negatively with salivary flow rate, -amylase activity and total protein content; however, salivary oxidation products do not reflect their plasma level. In conclusion, children with CKD suffer from salivary gland dysfunction. Oxidation of salivary proteins and lipids increases with CKD progression and deterioration of salivary gland function.

A Longitudinal Study of the Antioxidant Barrier and Oxidative Stress in Morbidly Obese Patients after Bariatric Surgery. Does the Metabolic Syndrome Affect the Redox Homeostasis of Obese People?

This is the first study to evaluate both the antioxidant barrier, glutathione metabolism, and oxidative damage to proteins and lipids in morbidly obese patients undergoing bariatric treatment. The study included 65 patients with class 3 obesity divided into two subgroups: morbidly obese patients without metabolic syndrome (OB) and obese patients with metabolic syndrome (OB + MS). Blood samples were collected before surgery as well as one, three, six, and twelve months after the bariatric treatment. Superoxide dismutase and reduced glutathione (GSH) were significantly decreased, whereas glutathione reductase and uric acid were enhanced in morbidly obese patients before bariatric surgery as compared to lean control. Moreover, in the OB group, we observed the increase of superoxide dismutase (SOD) and the decrease of uric acid (UA) after the bariatric treatment; however, these changes were not observed in the OB + MS group. The oxidative damage to proteins (advanced glycation end products, AGE; advanced oxidation protein products, AOPP) and lipids (8-isoprostanes, 8-isop; 4-hydroxynoneal) was higher in OB as well as OB + MS patients. We noticed that AGE and AOPP levels diminished after the bariatric treatment, whereas redox status (ratio of GSH to oxidized glutathione) was still reduced in the OB + MS group. Summarizing, morbid obesity is associated with disturbances in the antioxidant barrier and enhanced oxidative damage to proteins and lipids. Although bariatric surgery improves redox homeostasis in obese patients, those with metabolic syndrome show a continuous decrease in the antioxidant status. In patients undergoing bariatric treatment, antioxidant supplementation may be considered.

A Case-Control Study of Salivary Redox Homeostasis in Hypertensive Children. Can Salivary Uric Acid be a Marker of Hypertension?

Oxidative stress plays a critical role in the pathogenesis of hypertension; however, there are no data on salivary redox homeostasis and salivary gland function in children with hypertension. A total of 53 children with hypertension and age- and sex-matched controls were classified for the study. The antioxidant barrier and oxidative/nitrosative stress were evaluated in non-stimulated (NWS) and stimulated (SWS) whole saliva, plasma, and erythrocytes, with Student's t-test and Mann-Whitney U-test used for statistical analysis. We demonstrated that the activities of superoxide dismutase, catalase, and peroxidase were significantly higher in NWS, SWS, and erythrocytes of children with hypertension, similar to oxidative damage in proteins (advanced glycation end products) and lipids (malondialdehyde) as well as nitrosative stress markers (peroxynitrite and nitrotyrosine). The level of uric acid (UA) was significantly higher in NWS, SWS, and plasma of children with hypertension. UA concentration in SWS correlated positively with systolic and diastolic blood pressure and UA content in plasma. This parameter differentiates children with hypertension from healthy controls (AUC = 0.98) with a high degree of sensitivity (94%) and specificity (94%). Stimulated salivary flow was significantly lower in the hypertension group, similar to total protein content and salivary amylase activity. In summary, childhood hypertension is associated with hyposalivation as well as disturbances in antioxidant defense and enhanced oxidative/nitrosative damage both in the plasma/erythrocytes as well as saliva. Salivary UA may be a potential biomarker of hypertension in children.

Salivary Redox Biomarkers in Selected Neurodegenerative Diseases

Neurodegenerative diseases (NDDs), such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, are disorders, which cause irreversible and progressive deterioration of the central nervous system. The pathophysiology of NDDs is still not fully explained; nevertheless, oxidative stress is considered as a critical mediator of cerebral degeneration, brain inflammation, as well as neuronal apoptosis. Therefore, it is not surprising that redox biomarkers are increasingly used in the diagnosis of neurodegenerative diseases. As saliva is a very easy to obtain bioliquid, it seems promising to use this biomaterial in the diagnosis of NDDs. Saliva collection is easy, cheap, stress-free, and non-infectious, and it does not require the help of a specialised medical personnel. Additionally, the concentrations of many salivary redox biomarkers correlate with their content in blood serum as well as the degree of disease progression, which makes them non-invasive indicators of NDDs. This paper reviews the latest knowledge concerning the use of salivary redox biomarkers in the diagnosis and prognosis of selected neurodegenerative diseases.

Salivary Antioxidants and Oxidative Stress in Psoriatic Patients: Can Salivary Total Oxidant Status and Oxidative Status Index Be a Plaque Psoriasis Biomarker?

The aim of our research was to evaluate redox balance parameters and biomarkers of oxidative stress (OS) in nonstimulated and stimulated saliva as well as the blood of patients with plaque psoriasis compared to healthy controls. The study involved 40 patients with plaque psoriasis and 40 generally healthy subjects matched by age and gender to the study group patients. We assayed the concentration/activity of antioxidant enzymes: salivary peroxidase (Px), catalase (CAT), and superoxide dismutase (SOD) measured in unstimulated saliva (NWS), stimulated saliva (SWS), and erythrocytes. In plasma as well as NWS and SWS, we measured the concentration/activity of reduced glutathione (GSH), total antioxidant potential (TAC), total oxidative status (TOS), oxidative stress index (OSI), and markers of oxidative modification of proteins: advanced glycation end products (AGE), advanced oxidation protein products (AOPP), and lipid oxidation products: malondialdehyde (MDA) and total lipid hydroperoxide (LOOH). In NWS and SWS, we also evaluated the rate of reactive oxygen species (ROS) production. The concentration of Px, CAT, and SOD was significantly higher in NWS of patients with plaque psoriasis vs. healthy subjects. In SWS of psoriatic patients, we observed considerably higher concentration of Px and CAT, and in erythrocytes of patients with plaque psoriasis, the concentration of GPx and CAT was significantly higher compared to that in the controls. The levels of AOPP, AGE, MDA, and LOOH were considerably higher in NWS, SWS, and plasma of the study group compared to the controls. The concentration of total protein and salivary amylase was significantly lower in NWS and SWS of psoriatic patients compared to the healthy control. In the course of plaque psoriasis, we observed redox imbalances with prevalence of oxidation reactions. Mechanisms involved in the synthesis/secretion of proteins and activity of amylase were depressed in both glands of psoriatic patients; however, they were more inhibited in the parotid gland compared to the submandibular gland. TOS concentration and OSI value in NWS and SWS may serve as diagnostic biomarkers of plaque psoriasis.

Free Radical Production, Inflammation and Apoptosis in Patients Treated With Titanium Mandibular Fixations-An Observational Study

Despite high biocompatibility of titanium and its alloys, this metal causes various side effects in the human body. It is believed that titanium biomaterials may induce an innate/adaptive immune response. However, still little is known about changes caused by titanium mandible implants, particularly with regard to bone healing. The latest studies showed disturbances in the antioxidant barrier, increased oxidative/nitrosative stress, as well as mitochondrial abnormalities in the periosteum covering titanium mandible fixations; nevertheless, the impact of titanium implants on free radical production, inflammation, and mandible apoptosis are still unknown. Because severe inflammation and apoptosis are among the main factors responsible for disturbances in osteointegration as well as implant rejection, this study is the first to evaluate pro-oxidant enzymes, cytokines as well as pro- and anti-apoptotic proteins in the periosteum of patients with a broken jaw, treated with titanium miniplates and miniscrews. The study group consisted of 29 patients with double-sided fracture of the mandible body requiring surgical treatment. We found significantly higher activity of NADPH oxidase and xanthine oxidase as well as enhanced rate of free radical production in the periosteum of patients in the study group compared to the control group. The markers of inflammation [interleukin 1 (IL-1), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), transforming growth factor β (TGF-β) and β-glucuronidase (GLU)] as well as apoptosis [Bax, Bax/Bcl-2 ratio, caspase-3 (CAS-3) and nitric oxide (NO)] were significantly elevated in periosteum covering titanium fixations compared to the control group. In the study group, we also demonstrated an increased content of titanium on the periosteum surface, which positively correlated with CAS-3 activity. The study led us to the conclusion that titanium mandible implants increase the production of pro-inflammatory cytokines, and enhance free radical generation in the periosteum covering titanium miniplates and miniscrews. Additionally, exposure to Ti6Al4V titanium alloy induces apoptosis in the mandible periosteum. However, no clinical signs of the said phenomena have been observed.

Salivary FRAP as A Marker of Chronic Kidney Disease Progression in Children

Chronic kidney disease (CKD) is one of the most common modern-age diseases in children. Kidney failure does not reveal any symptoms for a long time; therefore, new biomarkers are sought, preferably those reflecting an early stage of CKD. The aim of our study was to evaluate total antioxidant potential as a biomarker differentiating the degree of CKD advancement. The study included 30 children with CKD and a control group matched by age and gender. Non-stimulated saliva (NWS), stimulated saliva (SWS), plasma and urine were used as study material. Total antioxidant potential was determined spectrophotometrically using the FRAP method (ferric ion reducing antioxidant parameter) by measuring total FRAP and uric acid (UA)-independent FRAP (FRAP-UA). We demonstrated that total FRAP, FRAP-UA and UA were significantly higher in stimulated saliva, as well as urine of CKD patients compared to the controls. These biomarkers increase with the progression of chronic kidney disease and their concentration in SWS reflects their content in urine. Interestingly, salivary FRAP and uric acid clearly differentiate between various stages of CKD as well as between healthy and ill children. Special attention should be paid to total FRAP which-measured in SWS-distinguishes patients with mildly to moderately decreased kidney function from those with severe renal impairment (AUC = 1, sensitivity = 100%, specificity = 100%). Although salivary FRAP may be a potential CKD biomarker in children, further studies are needed in a larger group of patients.

The Impact of a Diet Containing Sucrose and Systematically Repeated Starvation on the Oxidative Status of the Uterus and Ovary of Rats

The effect of a sucrose diet and repeated one-day starvation on oxidative status in the ovary and uterus is still unknown. Our analysis focused on carbohydrate-lipid metabolism parameters and the changes in red blood cells, ovary and uterus superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and malonylodialdehyde (MDA) concentration in rats fed with a diet containing 16% of sucrose and subjected to systematic one-day starvation when using such a diet. It was found that a diet with 16% sucrose contributed to the increase of antioxidant enzyme activity in the blood (GPx and CAT) and uterus (SOD), without changes in MDA concentrations, which indicates an increase in reactive oxygen species (ROS) concentration in these tissues, being balanced by an increase in antioxidant enzyme activity. The introduction of a regular one-day starvation period into the diet intensified oxidative stress and led to a redox imbalance in the reproductive tissues of female rats. This was manifested by higher GPx activity, lower CAT activity and higher MDA concentration in the uterus and lower GPx and CAT activities and lower MDA concentration in the ovaries. The observed changes may be the cause of fertility disorders and possible problems with fertilised egg cell implantation into the uterine tissue.

Oxidative stress biomarkers in the serum and plasma of patients with non-alcoholic fatty liver disease (NAFLD). Can plasma AGE be a marker of NAFLD? Oxidative stress biomarkers in NAFLD patients

Still little is known about the redox abnormalities in patients with non-alcoholic fatty liver disease (NAFLD). The purpose of the study was to find the relationship between enzymatic and non-enzymatic antioxidants, redox homeostasis and oxidative damage in 67-patients with NAFLD. The study population was divided into patients with non-alcoholic fatty liver (early NAFLD, n = 29) and patients with non-alcoholic steatohepatitis (advanced NAFLD, n = 38). Redox biomarkers: enzymatic antioxidants (Cu - Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR)); non-enzymatic antioxidants and redox status (reduced glutathione (GSH), total antioxidant capacity (TAC)); and oxidative damage products (total oxidant status (TOS), advanced glycation end products (AGE), malondialdehyde (MDA), and DNA/RNA oxidative damage) were determined in the serum/plasma samples. The activity of SOD, GPx, GR and levels of GSH, TOS, AGE, MDA, and DNA/RNA oxidative damage were significantly elevated in early NAFLD and advanced NAFLD group compared to controls (p < .001). There was a positive correlation between AGE, TAC and ALT activity (R = 0.34, p = .04; R = 0.36, p = .03, respectively) in advanced NAFLD group. Interestingly, ROC analysis for AGE showed good discriminatory ratio for patients with minimal steatosis (BARD score 0-1) vs. moderate steatosis (BARD score 2-4), AUC = 0.76. Plasma AGE can be a potential non-invasive biomarker differentiating NAFLD patients.

The Impact of High-Fat Diet on Mitochondrial Function, Free Radical Production, and Nitrosative Stress in the Salivary Glands of Wistar Rats

Oxidative stress plays a crucial role in the salivary gland dysfunction in insulin resistance; however, the cause of increased free radical formation in these conditions is still unknown. Therefore, the aim of the study was to investigate the effect of high-fat diet (HFD) on the mitochondrial respiratory system, prooxidant enzymes, ROS production, and nitrosative/oxidative stress in the submandibular and parotid glands of rats. The experiment was performed on male Wistar rats divided into two groups (n = 10): control and HFD. The 8-week feeding of HFD affects glucose metabolism observed as significant increase in plasma glucose and insulin as well as HOMA-IR as compared to the control rats. The activity of mitochondrial Complex I and Complex II+III was significantly decreased in the parotid and submandibular glands of HFD rats. Mitochondrial cytochrome c oxidase (COX) activity and the hydrogen peroxide level were significantly increased in the parotid and submandibular glands of the HFD group as compared to those of the controls. HFD rats also showed significantly lower reduced glutathione (GSH) and reduced : oxidized glutathione (GSH : GSSG) ratio, as well as a higher GSSG level in the parotid glands of HFD rats. The activity of NADPH oxidase, xanthine oxidase, and levels of oxidative/nitrosative stress (malonaldehyde, nitric oxide, nitrotyrosine, and peroxynitrite) and inflammation/apoptosis (interleukin-1β and caspase-3) biomarkers were statistically elevated in the HFD group in comparison to the controls. HFD impairs mitochondrial function in both types of salivary glands by enhancing ROS production, as well as stimulating inflammation and apoptosis. However, free radical production, protein nitration, and lipid peroxidation were more pronounced in the parotid glands of HFD rats.

Short-term High Fructose Intake Reprograms the Transcriptional Clock Rhythm of the Murine Extraorbital Lacrimal Gland

Purpose

To determine whether high fructose intake (HFI) influences the daily transcriptional clock rhythms of murine extraorbital lacrimal glands (ELGs).

Methods

Timed ELGs were collected from two groups of C57BL/6J mice subjected to a 12-hour light/12-hour dark (LD) cycle for 10 days; the first group received water-only feeding and the second received water with 15% fructose. Total RNA was extracted and subjected to RNA sequencing. A JTK_CYCLE algorithm and computational software were used to determine the periodicity, rhythmicity, and amplitude of the cycling transcripts. The rhythmic transcripts from different conditions were analyzed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database.

Results

HFI feeding caused massive remodeling of the preexisting rhythmic genes in the normal control (NC)-fed ELGs. The induced transcripts in HFI-fed mice resulted in a profound reorganization of the coordinated transcriptional oscillations and KEGG pathways. Moreover, HFI feeding significantly altered the distribution of the KEGG pathways over an LD in the ELGs. Finally, we found that the ELGs have a robust core clock machinery and HFI feeding altered amplitude and the peak phase of clock gene transcriptional oscillation in ELGs.

Conclusions

Short-term HFI reprograms the daily transcriptomic oscillation of murine ELGs. This information may deepen our understanding of the outcomes of lacrimal glands altered by nutritional challenge.

Antioxidant Defense, Oxidative Modification, and Salivary Gland Function in an Early Phase of Cerulein Pancreatitis

Acute pancreatitis (AP) is a multifactorial disease characterized by necroinflammatory changes of the pancreas. Our study is the first study which evaluated the relationship between the free radical production, enzymatic and nonenzymatic antioxidants, oxidative damage, and secretory function of the salivary glands of AP rats. Male Wistar rats were divided equally into 2 groups: control (n = 9) and AP (n = 9). AP was induced by intraperitoneal injection with cerulein and confirmed by higher serum amylase and lipase. We have demonstrated that the superoxide dismutase and glutathione reductase activities, as well as reduced glutathione concentration, were significantly decreased in both the parotid and submandibular glands of AP rats as compared to the control rats. The production of free radicals evidenced as dichlorodihydrofluorescein assay and the activity of NADPH oxidase and xanthine oxidase and IL-1β concentration were significantly higher in the parotid and submandibular glands of AP rats compared to the controls. In AP rats, we also showed a statistical increase in oxidation modification products (advanced glycation end products and advanced oxidation protein products), salivary amylase activity, and significant decrease in the total protein content. However, we did not show apoptosis and any morphological changes in the histological examination of the salivary glands of AP rats. To sum up, cerulein-induced AP intensifies production of oxygen free radicals, impairs the redox balance of the salivary glands, and is responsible for higher oxidative damage to these glands. Interestingly, oxidative modification of proteins and dysfunction of the antioxidant barrier are more pronounced in the submandibular glands of AP rats.

Insulin Resistance and Oxidative Stress in the Brain: What's New?

The latest studies have indicated a strong relationship between systemic insulin resistance (IR) and higher incidence of neurodegeneration, dementia, and mild cognitive impairment. Although some of these abnormalities could be explained by chronic hyperglycaemia, hyperinsulinemia, dyslipidaemia, and/or prolonged whole-body inflammation, the key role is attributed to the neuronal redox imbalance and oxidative damage. In this mini review, we provide a schematic overview of intracellular oxidative stress and mitochondrial abnormalities in the IR brain. We highlight important correlations found so far between brain oxidative stress, ceramide generation, β-amyloid accumulation, as well as neuronal apoptosis in the IR conditions.

Glutathione Metabolism, Mitochondria Activity, and Nitrosative Stress in Patients Treated for Mandible Fractures

The aim of the study was to evaluate the effect of titanium bone fixations on mitochondrial activity, reactive oxygen species (ROS) production, glutathione metabolism, and selected markers of oxidative/nitrosative stress in the periosteum-like tissue of patients treated with mandible fractures. The study group consisted of 30 patients with bilateral fractures of the mandible body eligible for surgical treatment. Our study is the first one that indicates disturbances of mitochondrial activity as well as a higher production of ROS in the periosteum-like tissue covering titanium fixations of the mandible. We also found significantly higher levels of reduced glutathione and enhanced activity of glutathione reductase in the periosteum homogenates of patients in the study group compared to the control group. Levels of nitrosative (S-nitrosothiols, peroxynitrite, nitrotyrosine) and oxidative stress biomarkers (malondialdehyde, protein carbonyls, dityrosine, kynurenine, and N-formylkynurenine) were statistically elevated in periosteum-like tissue covering titanium fixations. Although exposure to titanium fixations induces local antioxidant mechanisms, patients suffer oxidative damage, and in the periosteum-like tissue the phenomenon of metallosis was observed. Titanium implants cause oxidative/nitrosative stress as well as disturbances in mitochondrial activity.