Deoxyribonuclease partially ameliorates thioacetamide-induced hepatorenal injury.

Several recent studies have shown that liver injury is associated with the release of DNA from hepatocytes. This DNA stimulates innate immunity and induces sterile inflammation, exacerbating liver damage. Similar mechanisms have been described for acute renal injury. Deoxyribonuclease degrades cell-free DNA and can potentially prevent some of the induced tissue damage. This study analyzed the effects of thioacetamide-induced hepatorenal injury on plasma DNA in rats. Plasma DNA of both nuclear and mitochondrial origin was higher in thioacetamide-treated animals. Administration of deoxyribonuclease resulted in a mild, nonsignificant decrease in total plasma DNA and plasma DNA of mitochondrial origin but not of nuclear origin. This was accompanied by a decrease in bilirubin, creatinine, and blood urea nitrogen as markers of renal function. In conclusion, the study confirmed the hepatotoxic and nephrotoxic effect of thioacetamide. The associated increase in cell-free DNA seems to be involved in hepatorenal pathogenesis because treatment with deoxyribonuclease resulted in a partial prevention of hepatorenal injury. Further experiments will focus on the effects of long-term treatment with deoxyribonuclease in other clinically more relevant models. Clinical studies should test endogenous deoxyribonuclease activity as a potential risk determinant for kidney or liver failure.NEW & NOTEWORTHY Thioacetamide-induced hepatorenal injury resulted in higher plasma cell-free DNA. Deoxyribonuclease decreased average cell-free DNA of mitochondrial origin but not nuclear origin. Deoxyribonuclease partially prevented hepatorenal injury in rats.

The renal effects of prenatal testosterone in rats.

PURPOSE: Previous studies have shown that prenatal testosterone affects the development of not only reproductive organs but also the brain and even glucose metabolism. Whether prenatal testosterone influences the kidney development is largely unknown. We analyzed whether testosterone modulation during prenatal development would affect renal function and the number of nephrons in adult offspring. MATERIALS AND METHODS: Pregnant rats were treated with olive oil, testosterone (2 mg/kg), the androgen receptor blocker flutamide (5 mg/kg) or testosterone plus flutamide via daily intramuscular injections from gestation day 14 until delivery. Renal histology and functional parameters were assessed in male and female adult offspring. Macerated kidneys were used for nephron counting. RESULTS: Prenatal testosterone administration increased proteinuria in male rats by 256%. A similar 134% effect in female rats was not statistically significant. This effect was prevented when flutamide was co-administered. In male rats prenatal testosterone increased blood urea nitrogen. In female rats flutamide increased creatinine clearance. In male rats prenatal testosterone and flutamide led to higher and lower, respectively, interstitial collagen deposition in adulthood. CONCLUSIONS: Prenatal testosterone induces proteinuria in adulthood. This effect is mediated via androgen receptor. Additional effects seem to be sex specific. Further studies should focus on the timing and dosing of testosterone as well as the applicability to human development.

Salivary markers of oxidative stress in patients with obstructive sleep apnea treated with continuous positive airway pressure.

PURPOSE: Obstructive sleep apnea syndrome (OSAS) is characterized by elevated oxidative stress. Measurement of oxidative stress in saliva seems to be promising in long-term treatment monitoring of OSAS patients. In this study, our aim was to investigate whether short-term continuous positive airway pressure (CPAP) treatment would influence oxidative stress in saliva. METHODS: Patients with diagnosed OSAS (16 women, 28 men) underwent polysomnography during the first night and CPAP treatment during the second night. Saliva samples were taken in the evening and morning on both days. Markers of oxidative stress and antioxidant status were analyzed in saliva. RESULTS: Evening concentrations of the salivary thiobarbituric acid reacting substances (p < 0.001), advanced glycation end-products (p < 0.001), and advanced oxidation protein products (p < 0.01) were significantly lower than morning values during the diagnostic night. However, salivary concentrations of none of the oxidative stress markers were significantly influenced by the CPAP treatment. No changes in salivary antioxidant status after CPAP therapy were found. CONCLUSION: Salivary markers of oxidative stress and antioxidant status do not change significantly after one night treatment with CPAP. On the contrary, after 1 month with CPAP therapy, reduced markers of oxidative stress were reported. Therefore, the future studies should be focused on finding the optimal sampling frequency to clarify the potential of saliva for the monitoring of OSAS treatment.

Sex differences of oxidative stress markers in young healthy subjects are marker-specific in plasma but not in saliva.

BACKGROUND: Several studies showed there are sex differences in oxidative stress. An observational study analysing oxidative stress markers in young healthy men and women is lacking. Moreover, it is unclear whether the differences are related to sex hormones. AIM: The primary goal was to analyse differences in oxidative stress markers with regard to sex in plasma of young healthy subjects and whether differences are related to sex hormones. The secondary study compared oxidative stress markers in plasma with salivary samples. METHODS: Plasma and saliva samples were analysed from 158 young healthy probands. Established spectro-photometric/fluorometric methods were used to quantify oxidative stress markers. Sex hormones were measured using ELISA kits. RESULTS: In plasma, malondialdehyde and advanced glycation end products were significantly higher in women. Advanced oxidation protein products and the ferric reducing ability of plasma were higher in men. Sex hormones were not associated with oxidative stress markers. In saliva, analysed markers of antioxidant status were higher in men, but no sex differences were found in other markers. CONCLUSION: Observed parameters showed marker-specific sex differences in plasma, but these differences were not related to sex hormones. Plasma and saliva concentrations of biomarkers did not correlate, reflecting oral but not systemic conditions.

Phage survival: the biodegradability of M13 phage display library in vitro.

Administration of bacteriophages is used for phage therapy modulation of gut microbiome or for in vivo phage display. The aim of the study was to analyze the survival of M13 phage in different body fluids and tissues in vitro. The survival of M13 phage was measured in vitro in human blood, saliva, urine, artificial gastric juice (AGJ), and mouse homogenates of stomach, jejunum, and colon after defined time points (5, 15, or 45 Min). The plates were inspected after overnight incubation and the plaques were counted. No phage was recovered after 5 Min of incubation with AGJ. In urine, the phage survival was decreased by 44% after 5 Min of incubation (P = 0.004). In saliva, the recovered titer was decreased by 33% and 88% (P < 0.05) after 15 and 45 Min, respectively. Phage coincubation with jejunum homogenate led to significant decrease of phage titer by 72% (P < 0.01) after 15 Min and by 99% (P < 0.001) after 45 Min. Decreased survival of M13 phage depending on time of incubation was proved under several in vitro conditions, with low pH in the AGJ having the most detrimental effect on phage survival. Phage pharmacokinetics described in vitro might have applications for the use of bacteriophages in vivo.

Molecular actions of sex hormones in the brain and their potential treatment use in anxiety disorders.

Anxiety disorders are one of the most prevalent mood disorders that can lead to impaired quality of life. Current treatment of anxiety disorders has various adverse effects, safety concerns, or restricted efficacy; therefore, novel therapeutic targets need to be studied. Sex steroid hormones (SSHs) play a crucial role in the formation of brain structures, including regions of the limbic system and prefrontal cortex during perinatal development. In the brain, SSHs have activational and organizational effects mediated by either intracellular or transmembrane G-protein coupled receptors. During perinatal developmental periods, the physiological concentrations of SSHs lead to the normal development of the brain; however, the early hormonal dysregulation could result in various anxiety diorders later in life. Sex differences in the prevalence of anxiety disorders suggest that SSHs might be implicated in their development. In this review, we discuss preclinical and clinical studies regarding the role of dysregulated SSHs signaling during early brain development that modifies the risk for anxiety disorders in a sex-specific manner in adulthood. Moreover, our aim is to summarize potential molecular mechanisms by which the SSHs may affect anxiety disorders in preclinical research. Finally, the potential effects of SSHs in the treatment of anxiety disorders are discussed.

Behavioral Changes During Development of Chronic Kidney Disease in Rats.

Decreased renal function due to chronic kidney disease (CKD) is associated with anxiety and cognitive decline. Although these mental disorders are often obvious in late stage renal disease patients, they might be unnoticeable or are neglected in early stages of the CKD development. Associations between renal and cognitive dysfunction have been indicated by studies performed mainly in patients undergoing dialysis, which itself represents a stress and decreased quality of life. However, experimental and causal studies are scarce. Our aim was to investigate dynamic changes in behavioral traits during the progression of CKD in an animal model. Thirty 12-week old male rats were used in this experiment. CKD was induced by a subtotal (5/6) nephrectomy. Two, 4, and 6 months after surgical induction of CKD, the open field, the light-dark box and the novel object recognition tests were conducted to assess the locomotor activity, anxiety-like behavior and the memory function of rats. Blood urea nitrogen (BUN), plasma concentration of creatinine (CREAT), albumin to creatinine ratio in urine (ACR) along with the renal histology were assessed to monitor the development and severity of CKD. In comparison to control rats, 5/6 nephrectomized rats had by 46-66% higher concentration of BUN during the whole follow-up period, as well as by 52% and by 167% higher CREAT and ACR, respectively, 6 months after surgery. Although the effect of time was observed in some behavioral parameters, nephrectomy did not significantly influence either locomotor activity, or anxiety-like behavior, or memory function of animals. Two and 4 months after surgery, animals moved shorter distance and spent less time in the center zone. However, the open-field ambulation returned back to the baseline level 6 months after CKD induction. Although nephrectomized rats displayed impaired kidney function as early as 2 months after surgery, no significant differences were found between the CKD and the control rats in any of the observed behaviors. Further studies are needed in order to evaluate whether behavioral abnormalities are related to severity of CKD or might be attributed to psychosocial aspect of end-stage renal disease and decreased quality of life in dialysis patients.

Oxidative Stress and Antioxidants in the Diagnosis and Therapy of Periodontitis.

Oxidative stress has been implicated in the pathogenesis of numerous diseases. However, large interventional studies with antioxidants failed to show benefits in the prevention or treatment of cardiovascular diseases, cancer, or diabetes mellitus. Numerous clinical studies have confirmed the association of oxidative stress markers and periodontitis. Technical and biological variability is high for most of the analyzed markers and none of them seems to be optimal for routine clinical use. In a research setting, analysis of a palette of oxidative stress markers is needed to cover lipid peroxidation, protein oxidation, and the antioxidant status. The source of reactive oxygen species and their role in the pathogenesis of periodontitis remains unclear. Interventional experiments indicate that oxidative stress might be more than just a simple consequence of the inflammation. Small studies have confirmed that some antioxidants could have therapeutic value at least as an addition to the standard non-surgical treatment of periodontitis. A clear evidence for the efficiency of antioxidant treatment in large patient cohorts is lacking. Potentially, because lowering of oxidative stress markers might be a secondary effect of anti-inflammatory or antibacterial agents. As the field of research of oxidative stress in periodontitis gains attraction and the number of relevant published papers is increasing a systematic overview of the conducted observational and interventional studies is needed. This review summarizes the currently available literature linking oxidative stress and periodontitis and points toward the potential of adjuvant antioxidant treatment, especially in cases where standard treatment fails to improve the periodontal status.

Variability of salivary markers of oxidative stress and antioxidant status in young healthy individuals.

OBJECTIVES: Salivary advanced glycation end-products (AGEs), advanced oxidation protein products (AOPP), total antioxidant capacity (TAC), and ferric reducing ability of saliva (FRAS) are increased in various diseases. Little data exist for these markers in the healthy population. The aim of this study was to assess the inter-individual and intra-individual variability of AGEs, AOPP, TAC, and FRAS in the saliva of young healthy individuals. METHODS: Unstimulated saliva samples were collected from 16 females and 18 males daily over a period of 30 days. Markers were measured using spectrophotometric and spectrofluorometric microplate-based methods. RESULTS: All salivary markers measured were significantly higher in men than in women (P < 0.05 for AGEs; P < 0.001 for AOPP, TAC, and FRAS). The inter-individual variability was approximately 60% for AGEs and AOPP and 30-40% for TAC and FRAS in both genders. The inter-individual variability of FRAS was higher in men vs. women (P < 0.01). Intra-individual variability ranged from 20% for TAC, to 30% for AGES and FRAS and 45% for AOPP. DISCUSSION: Intra-individual variability of salivary AGEs, AOPP, TAC, and FRAS indicates that their use is currently limited to large cohort studies. Identifying the underlying factors related to the high inter-individual and intra-individual variability is needed. Sex differences should be considered in future studies.

Salivary markers of oxidative stress in oral diseases.

Saliva is an interesting alternative diagnostic body fluid with several specific advantages over blood. These include non-invasive and easy collection and related possibility to do repeated sampling. One of the obstacles that hinders the wider use of saliva for diagnosis and monitoring of systemic diseases is its composition, which is affected by local oral status. However, this issue makes saliva very interesting for clinical biochemistry of oral diseases. Periodontitis, caries, oral precancerosis, and other local oral pathologies are associated with oxidative stress. Several markers of lipid peroxidation, protein oxidation and DNA damage induced by reactive oxygen species can be measured in saliva. Clinical studies have shown an association with oral pathologies at least for some of the established salivary markers of oxidative stress. This association is currently limited to the population level and none of the widely used markers can be applied for individual diagnostics. Oxidative stress seems to be of local oral origin, but it is currently unclear whether it is caused by an overproduction of reactive oxygen species due to inflammation or by the lack of antioxidants. Interventional studies, both, in experimental animals as well as humans indicate that antioxidant treatment could prevent or slow-down the progress of periodontitis. This makes the potential clinical use of salivary markers of oxidative stress even more attractive. This review summarizes basic information on the most commonly used salivary markers of oxidative damage, antioxidant status, and carbonyl stress and the studies analyzing these markers in patients with caries or periodontitis.

Salivary markers of oxidative stress and antioxidant status: influence of external factors.

BACKGROUND: Salivary markers of oxidative stress and antioxidant status represent promising tool for the research of oral diseases. One of the criteria is the validation of these biomarkers from the perspective of the confounding and modifying factors. AIM: To examine the effect of circadian rhythm, tooth-brushing and ascorbic acid treatment on selected salivary markers of oxidative and carbonyl stress, and antioxidant status. SUBJECTS AND METHODS: Whole unstimulated saliva samples were collected from 19 healthy participants three times during a day, before and after tooth-brushing, and before and after the administration of vitamin C (250 mg). Advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS), advanced glycation end products (AGEs), ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) were measured. RESULTS: Salivary AGEs levels varied significantly during the day (p< 0.05) with the highest concentrations in the morning. FRAP levels varied during the day (p < 0.01) with the highest concentrations in the afternoon. Tooth-brushing decreased AGEs (p< 0.05) and TBARS levels (p< 0.01) and increased FRAP levels (p< 0.05). Single intake of vitamin C significantly decreased AGEs (p < 0.001) and increased both FRAP (p< 0.01) and TAC (p< 0.01) concentrations. CONCLUSION: Significant daily variations were observed in salivary AGEs and FRAP levels. Tooth-brushing and treatment with vitamin C decreased carbonyl stress and increased the antioxidant status. These results are important from the perspective of using saliva for the research of oral diseases.

Salivary markers of oxidative stress and their relation to periodontal and dental status in children.

BACKGROUND: Previous studies have shown that salivary thiobarbituric acid reactive substances are related to the periodontal status in adults. Such an analysis has not been done on children yet. The aim of our study was to analyze salivary markers of oxidative stress in relation to periodontal and dental status in children. METHODS: The periodontal and dental status of 82 consecutive pediatric dental patients was assessed. The oral hygiene index (OHI), the papillary bleeding index (PBI) and the caries index (CI) were assessed as clinical parameters. Markers of oxidative stress and antioxidant status were measured in whole saliva samples. RESULTS: Multivariate analysis of covariance showed that the variability of PBI explains 10.9% of the variance of salivary thiobarbituric acid reacting substances (TBARS). Advanced oxidation protein products (AOPP) were related to CI (eta 8.6%). Measures of antioxidant status (total antioxidant capacity and ferric reducing ability of saliva) were partially determined by OHI (13.6% and 7.2%) and PBI (16.9% and 7.9%). CONCLUSIONS: Antioxidant status in saliva is related to oral hygiene and periodontal status. Salivary TBARS are a potential sensitive marker of periodontitis in children, similarly to adults, at least on a population level. Salivary AOPP are related to caries. Potential diagnostic value of the analyzed markers should be analyzed in further interventional studies.