Intranasal oxytocin in a genetic animal model of autism.

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders mainly characterized by deficient sociability and repetitive behaviors. Effective treatment for the core symptoms of ASD is still lacking. Behavioral interventions show limited effectiveness, while pharmacotherapy focuses on the amelioration of secondary symptomatology. Oxytocin (OXT) is a neuropeptide known for its prosocial impact, making it a candidate drug for ASD treatment. Its alleviating effect has been and still is widely researched, but outcomes reported by clinical studies are ambiguous. We examined the effect of daily intranasal OXT (0.8 IU/kg) administration for 4 weeks on the ASD-like phenotype in Shank3-/- adult mice. Animals treated with OXT spent twice as much time interacting with the social partner as early as after 2 weeks of treatment. Furthermore, OXT-treated mice exhibited reduced explorative behavior by 50%, after 4 weeks of treatment, and a 30% reduction in repetitive behavior, 4 weeks after treatment termination. One-fold higher sociability and 30% reduced exploration due to OXT lasted up to 4 weeks following the treatment termination. However, social disinterest was elevated by roughly 10% as well, indicating a form of social ambivalence. Obtained results support the therapeutic potential of intranasally administered OXT in alleviating social shortfalls in a genetic model of ASD. Subsequent research is necessary to elucidate the benefits and risks of the long-term OXT administration, as well as its applicability in other ASD models and the potential treatment effect on social communication, which was not measured in the present study.

The Effect of Cross-Sex Fecal Microbiota Transplantation on Metabolism and Hormonal Status in Adult Rats.

Increasing evidence of sexual dimorphism in the pathophysiology of metabolic complications caused by sex steroids is under investigation. The gut microbiota represents a complex microbial ecosystem involved in energy metabolism, immune response, nutrition acquisition, and the health of host organisms. Gender-specific differences in composition are present between females and males. The purpose of this study was to use cross-sex fecal microbiota transplantation (FMT) for the detection of sex-dependent metabolic, hormonal, and gut microbiota changes in female and male recipients. Healthy non-obese female and male Wistar rats were divided into donor, same-sex, and cross-sex recipient groups. After a 30-day period of FMT administration, biochemical markers (glucose and lipid metabolism) and sex hormones were measured, and the gut microbiota was analyzed. The cross-sex male recipients displayed a significantly lower testosterone concentration compared to the males that received same-sex FMT. Sex-dependent changes caused by cross-sex FMT were detected, while several bacterial taxa correlated with plasma testosterone levels. This study represents the first to study the effect of cross-sex changes in the gut microbiome concerning metabolic and hormonal changes/status in adult non-obese Wistar rats. Herein, we present cross-sex FMT as a potential tool to modify sex-specific pathologies.

DNA in fresh urine supernatant is not affected by additional centrifugation and is protected against deoxyribonuclease.

Urinary DNA is widely studied as a non-invasive marker for monitoring of kidneys after transplantation or the progression of urinary tract tumors. The quantity of urinary DNA especially of mitochondrial origin has been reported to mirror kidney damage in various renal diseases and their models. Processing of samples might affect urinary DNA concentrations but the details are not clear. Samples of urine were collected from fifteen healthy volunteers. DNA was extracted from the whole urine, but also from the supernatant after centrifugation at 1600 g and 16000 g. In addition, we have analyzed the DNA in the microparticles in the pellet after the last spin. DNA was measured using fluorometry and real time PCR targeting nuclear and mitochondrial sequences. Addition of deoxyribonuclease to aliquots of samples enabled the characterization of DNA protection. Centrifugation at 1600 g decreased the concentration of extracted DNA by 66% at least in samples with higher DNA in whole urine. Interestingly, the additional spin at 16000 g did not result in a significant decrease in DNA concentration in the supernatant despite detectable microparticle-associated DNA. Deoxyribonuclease decreases total and nuclear DNA by 26% and 31% in whole urine. The majority of urinary mitochondrial DNA seems to be protected against deoxyribonuclease. Our results indicate high variability in urinary DNA even in healthy probands. Extracellular urinary DNA is partially bound to cell debris or microparticles, but a considerable part is still in the supernatant and is protected against cleavage. Further research should identify the nature of the protection, especially for mitochondrial DNA. Better understanding of the biology of urinary DNA should help its clinical interpretation.

Investigation of the Presence of DNA in Human Blood Plasma Small Extracellular Vesicles.

Extracellular DNA (ecDNA) is DNA outside of cells, which is a result of various mechanisms. EcDNA is believed to be a cause of various pathogeneses as well as their potential biomarker. EcDNA is believed to also be part of small extracellular vesicles (sEVs) from cell cultures. If ecDNA is present in sEVs in plasma, their membrane may protect it from degradation by deoxyribonucleases. Moreover, sEVs play a role in the intercellular communication, and they can therefore transfer ecDNA between cells. The aim of this study was to investigate the presence of ecDNA in sEVs isolated from fresh human plasma by the ultracentrifugation and density gradient, which serves to exclude the co-isolation of non-sEVs compartments. The novelty of the current study is the investigation of the localization and subcellular origin of the ecDNA associated with sEVs in plasma, as well as the estimation of the approximate concentration. The cup-shaped sEVs were confirmed by transmission electron microscopy. The highest concentration of particles was in the size of 123 nm. The presence of the sEVs markers CD9 and TSG101 was confirmed by western blot. It was found that 60-75% of DNA is on the surface of sEVs, but a part of the DNA is localized inside the sEVs. Moreover, both nuclear and mitochondrial DNA were present in plasma EVs. Further studies should focus on the potential harmful autoimmune effect of DNA carried by plasma EVs or specifically sEVs.

Endogenous DNase Activity in an Animal Model of Acute Liver Failure.

Deoxyribonucleases (DNases) cleave extracellular DNA (ecDNA) and are under intense research as interventions for diseases associated with high ecDNA, such as acute live injury. DNase I treatment decreases morbidity and mortality in this animal model. Endogenous DNase activity has high interindividual variability. In this study, we tested the hypothesis that high endogenous DNase activity is beneficial in an animal model of acute liver failure. DNase activity was measured in the plasma of adult male mice taken before i.p. injection of thioacetamide to induce acute liver failure. The survival of mice was monitored for 48 h. Mice were retrospectively divided into two groups based on the median DNase activity assessed using the gel-based single-radial enzyme diffusion assay. In acute liver failure, mice with a higher baseline DNase activity had lower mortality after 48 h (by 25%). Different protection of ecDNA against nucleases by vesicles or DNA-binding proteins could play a role and should be further evaluated. Similarly, the role of endogenous DNase activity should be analyzed in other disease models associated with high ecDNA.

Variability of endogenous deoxyribonuclease activity and its pathophysiological consequences.

Deoxyribonucleases (DNases) are enzymes that cleave DNA. Some DNases are secreted outside of cells where they can cleave extracellular DNA (ecDNA). High concentration of ecDNA is associated with diseases such as sepsis, preeclampsia, and systemic lupus. DNA can be released from dying cells and is immunogenic. DNases cleave ecDNA and might prevent activation of the immune system. Low DNase activity could be disadvantageous in diseases where high amounts of ecDNA are released from dying cells. The relationship between DNase activity and ecDNA remains unknown. The lack of standard values in DNase activity makes the studies difficult to compare. This review focuses on summarizing methods for DNase activity measurements, the possible implication of decreased DNase activity in diseases, and the impact on diseases associated with a high concentration of ecDNA.

Dynamics of Plasma and Urinary Extracellular DNA in Acute Kidney Injury.

Early and reliable markers of acute kidney injury (AKI) are essential. One such candidate marker of tissue damage is extracellular DNA (ecDNA). The aim of our present study is to describe the unknown dynamics of ecDNA in an animal model of AKI. Glycerol-induced nephropathy was used to model AKI in adult male Wistar rats (n = 93). Blood and urine samples were collected 1, 3, and 24 h after model induction. Total ecDNA and its sub-cellular origin was assessed. In the plasma, total ecDNA and nuclear ecDNA were significantly increased in the AKI group already after 1 h (160% and 270%, respectively, p = 0.02 and p = 0.04). Both nuclear and mitochondrial ecDNA were higher after 3 h (180% and 170%, respectively, p = 0.002 and p = 0.005). Urinary ecDNA concentrations in the AKI group were significantly increased only 24 h after model induction (130% for total ecDNA, p = 0.009; 210% for nuclear ecDNA, p = 0.02; and 200% for mitochondrial ecDNA, p = 0.0009). Our results indicate that plasma ecDNA has the potential to serve as an early and sensitive, albeit non-specific marker of AKI. Further studies should elucidate the source of ecDNA and the dynamics of ecDNA in other animal models of AKI and patients with AKI.

Circulating extracellular DNA is in association with continuous metabolic syndrome score in healthy adolescents.

Obesity is associated with chronic low-grade inflammation that eventually leads to metabolic complications. Extracellular DNA (ecDNA) is a damage-associated molecular pattern. Extracellular mitochondrial DNA can activate innate immunity. We hypothesized that ecDNA, especially of mitochondrial origin, could be associated with components of the metabolic syndrome in young healthy probands. In a cross-sectional study, healthy adolescents (n = 1,249) provided blood samples. Anthropometric data, blood pressure, and blood counts were assessed. In addition, biochemical analysis of sera or plasma was conducted, including the quantification of advanced oxidation protein products (AOPPs) as a marker of oxidative stress induced by neutrophil or monocyte activation. Plasma ecDNA was isolated and measured by fluorometry. Nuclear and mitochondrial DNA were quantified by real-time PCR. Males had higher total plasma ecDNA [15 (11-21) vs. 11 (8-17) ng/mL; median (interquartile range)], nuclear [1,760 (956-3,273) vs. 1,153 (600-2,292) genome equivalents (GE)/mL], and mitochondrial [37,181 (14,836-90,896) vs. 30,089 (12,587-72,286) GE/mL] DNA. ecDNA correlated positively with the continuous metabolic syndrome score (r = 0.158 for males and r = 0.134 for females). Stronger correlations were found between ecDNA of mitochondrial origin and AOPP (r = 0.202 and 0.186 for males and females, respectively). Multivariate regression analysis revealed associations of nuclear DNA with leukocyte and erythrocyte counts. The results of this study of healthy adolescents show that circulating ecDNA is associated with the risk of metabolic syndrome, not with obesity per se. The association between mitochondrial ecDNA and AOPP requires further attention as it supports a potential role of mitochondria-induced sterile inflammation in the pathogenesis of the metabolic syndrome.

Deoxyribonuclease activity negative correlates with extracellular DNA in uncomplicated singleton pregnancies in the third trimester.

OBJECTIVES: It is not clear, which factors affect extracellular DNA (ecDNA) concentrations in healthy women with singleton uncomplicated pregnancies, although deoxyribonucleases (DNases) are hypothesized to be responsible for the cleavage of plasma ecDNA. The aim of this study was to analyze potential determinants of total ecDNA including plasma DNase activity. METHODS: Plasma samples were collected from 48 healthy women with singleton uncomplicated pregnancies in the third trimester (gestation week 37). DNA was isolated and quantified using fluorometry and real time PCR. DNase activity was assessed using the single radial enzyme-diffusion method. RESULTS: Neither ecDNA, nor DNase activity were affected by maternal age or BMI. DNase activity negatively correlated with total plasma ecDNA (r=-0.40, p=0.007). Similar associations were found for ecDNA of nuclear and mitochondrial origin, but not with fetal DNA quantified using Y-targeted PCR in male fetus-bearing pregnancies. CONCLUSIONS: The role of plasma ecDNA of fetal and maternal origin is studied in the pathogenesis of pregnancy-complications. The results indicate that plasma DNase activity could negatively regulate ecDNA concentrations and should, thus, be analyzed in preeclampsia, preterm birth and other ecDNA-related pregnancy complications.

The Effect of Melatonin on Periodontitis.

BACKGROUND: Periodontitis is a chronic disease with a complex etiology that includes bacterial colonization, excessive inflammation, and oxidative stress. The hormone melatonin has antioxidant properties and might contribute to alleviating chronic conditions by reducing oxidative stress. The aim of this study was to analyze the effect of exogenous melatonin on periodontitis in an animal model of the disease as well as in patients with periodontitis. METHODS: In rats with ligature-induced periodontitis, melatonin was administered in drinking water for two weeks. In the human study, patients with treatment-resistant periodontitis were asked to rinse their mouths with a solution containing melatonin or placebo every evening for two weeks. Periodontal status as well as salivary markers of oxidative stress were assessed at the end of the study. RESULTS: Neither radiography nor µCT revealed any significant effects of melatonin on alveolar bone loss. Gum recession was the only improved macroscopic measure in rats (p < 0.05). Analysis of salivary markers of oxidative stress revealed no effects of treatment in rats or humans despite clearly elevated melatonin concentrations in melatonin treated groups. CONCLUSION: Our results do not support the use of melatonin for the treatment of periodontitis. However, the negative outcome is limited by the short duration of the study and the chosen route of application as well as the dose of melatonin.

The age-dependent effect of pre-pubertal castration on anxiety-like behaviour in male rats.

Adolescence is considered to be a critical period of sex hormone action (re)organising the brain and determining the behavioural phenotype. Such organisational effects in the brain might be the cause of sex differences in some behavioural features. In this experiment, we aimed to examine the role of pubertal sex hormones in development of anxiety in male rats. Male rats underwent gonadectomy prior to puberty onset, and were tested for explorative and anxiety-like behaviour in adolescence as well as in young adulthood. In adolescence, but not in adulthood, gonadectomised rats spend by 50% more time (p < .05) in the centre zone of the open-field than sham-operated counterparts. Young adult gonadectomised rats showed approximately 1.5-fold greater exploratory activity, in both open field (p < .001) and elevated plus maze (p < .01), in comparison with young adult control rats. Our results indicate that pre-pubertal castration may have test-specific anxiolytic effect in adolescent male rats, and it may attenuate the decline in explorative behaviour in young adult males. These differences in short- and long-term effects of gonadectomy could explain some contradictory results of previous studies on the role of testosterone in anxiety-like behaviour of male rodents. Thus, the age-specific consequences of pre-pubertal hormone deprivation should be considered.

Urea and creatinine levels in saliva of patients with and without periodontitis.

Despite the fact that saliva contains measurable concentrations of urea and creatinine, it is not widely used in clinical nephrology. One of the reasons is the high inter- and intra-individual variability in the salivary markers of kidney function. We hypothesized that gingival bleeding in patients with periodontitis could contribute to this variability by increasing the concentration of salivary urea or creatinine. Samples were collected from 25 patients with periodontitis and 29 healthy controls. In addition, saliva samples from five healthy volunteers were artificially contaminated with blood. The concentration of urea, but not that of creatinine, was more than twice as high in patients with periodontitis than in controls. Artificial contamination of saliva with blood did not affect the salivary concentration of creatinine. Salivary urea increased only with very high levels of contamination (≥2.5% blood in saliva), but that did not occur in patients. In conclusion, periodontitis increases the concentration of salivary urea, but this is not likely to be a result of contamination with blood. Future studies should investigate the composition of the oral microbiome, specifically regarding how it affects the concentration of salivary urea. Salivary creatinine seems to be a more robust non-invasive marker of renal functions than salivary urea.

Short-term effects of continuous positive airway pressure on oxidative stress in severe sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) is associated with oxidative stress that is involved in the pathogenesis of cardiovascular and metabolic complications. The concentrations of salivary markers of oxidative stress in patients with OSA increase considerably during the night. The dynamics is not affected by continuous positive airway pressure (CPAP) in mild to moderate OSA. The aim of this study was to analyze the short-term effects of CPAP on salivary oxidative stress markers in patients with severe OSA. METHODS: Salivary samples were collected from 24 patients with apnea-hypopnea index higher than 30 during the first (diagnostic) night, who were treated by CPAP during the second (therapeutic) night. RESULTS: The salivary markers of oxidative stress (TBARS, AGEs, and AOPP) were higher in the morning after the diagnostic night when compared to the evening concentrations (p < 0.01 for TBARS and p < 0.05 for AGEs and AOPP). Treatment by CPAP significantly decreased the morning concentrations of TBARS, AOPP (p < 0.01 for both), and AGEs (p < 0.05). Also, TBARS and AGEs positively correlated with apnea-hypopnea index (r = 0.48 and 0.49, respectively; p < 0.05). Antioxidant statuss was not affected. CONCLUSION: Severe OSA is associated with increased levels of saliva markers for lipid peroxidation, protein oxidative damage, and carbonyl damage. Even short-term CPAP partially prevents oxidative and carbonyl stress during the night and this can be monitored non-invasively using saliva.

Sex, Age, and Bodyweight as Determinants of Extracellular DNA in the Plasma of Mice: A Cross-Sectional Study.

Extracellular DNA (ecDNA) is studied as a possible biomarker, but also as a trigger of the immune responses important for the pathogenesis of several diseases. Extracellular deoxyribonuclease (DNase) activity cleaves ecDNA. The aim of our study was to describe the interindividual variability of ecDNA and DNase activity in the plasma of healthy mice, and to analyze the potential determinants of the variability, including sex, age, and bodyweight. In this experiment, 58 adult CD1 mice (41 females and 31 males) of a variable age (3 to 16 months old) and bodyweight (females 25.7 to 52.1 g, males 24.6 to 49.6 g) were used. The plasma ecDNA was measured using a fluorometric method. The nuclear ecDNA and mitochondrial ecDNA were quantified using real-time PCR. The deoxyribonuclease activity was assessed using the single radial enzyme diffusion method. The coefficient of variance for plasma ecDNA was 139%, and for DNase 48%. Sex differences were not found in the plasma ecDNA (52.7 ± 73.0 ηg/mL), but in the DNase activity (74.5 ± 33.5 K.u./mL for males, and 47.0 ± 15.4 K.u./mL for females). There were no associations between plasma ecDNA and bodyweight or the age of mice. Our study shows that the variability of plasma ecDNA and DNase in adult healthy mice is very high. Sex, age, and bodyweight seem not to be major determinants of ecDNA variability in healthy mice. As ecDNA gains importance in the research of several diseases, it is of importance to understand its production and cleavage. Further studies should, thus, test other potential determinants, taking into account cleavage mechanisms other than DNase.

Cell-free DNA: the role in pathophysiology and as a biomarker in kidney diseases.

Cell-free DNA (cfDNA) is present in various body fluids and originates mostly from blood cells. In specific conditions, circulating cfDNA might be derived from tumours, donor organs after transplantation or from the foetus during pregnancy. The analysis of cfDNA is mainly used for genetic analyses of the source tissue -tumour, foetus or for the early detection of graft rejection. It might serve also as a nonspecific biomarker of tissue damage in critical care medicine. In kidney diseases, cfDNA increases during haemodialysis and indicates cell damage. In patients with renal cell carcinoma, cfDNA in plasma and its integrity is studied for monitoring of tumour growth, the effects of chemotherapy and for prognosis. Urinary cfDNA is highly fragmented, but the technical hurdles can now be overcome and urinary cfDNA is being evaluated as a potential biomarker of renal injury and urinary tract tumours. Beyond its diagnostic application, cfDNA might also be involved in the pathogenesis of diseases affecting the kidneys as shown for systemic lupus, sepsis and some pregnancy-related pathologies. Recent data suggest that increased cfDNA is associated with acute kidney injury. In this review, we discuss the biological characteristics, sources of cfDNA, its potential use as a biomarker as well as its role in the pathogenesis of renal and urinary diseases.

Amniotic fluid cell-free DNA in preterm prelabor rupture of membranes.

INTRODUCTION: We evaluated the levels of cell-free nuclear DNA (nDNA) and cell-free mitochondrial DNA (mtDNA) in the amniotic fluid supernatant from pregnancies complicated by preterm prelabor rupture of membranes (PPROM) based on evidence of microbial invasion of the amniotic cavity (MIAC) and/or intra-amniotic inflammation (IAI). MATERIAL AND METHODS: A total of 155 women with PPROM were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis. The levels of cell-free nDNA and mtDNA in the amniotic fluid supernatant were assessed and quantified by real-time polymerase chain reaction. RESULTS: The levels of cell-free nDNA and mtDNA were higher in women with MIAC and IAI than in women without these conditions (nDNA: with MIAC: median 3.9 × 104 genome equivalent [GE]/mL vs without MIAC: median 1.2 × 104  GE/mL, with IAI: median: 5.3 × 104  GE/mL vs without IAI: median 1.2 × 104  GE/mL; mtDNA: with MIAC: median 9.2 × 105  GE/mL vs without MIAC: median 2.5 × 105  GE/mL, with IAI: median 1.1 × 106  GE/mL vs without IAI: median 2.5 × 105 ; all P values ≤ 0.01). Women with the microbial-associated IAI showed the highest levels of cell-free nDNA and mtDNA. CONCLUSIONS: Cell-free nDNA and mtDNA are constituents of the amniotic fluid supernatant from PPROM pregnancies. Both cell-free nDNA and mtDNA are involved in the intra-amniotic inflammatory response in women with PPROM.

17ß-Estradiol treatment reversed left ventricular dysfunction in castrated male rats: an echocardiographic study.

No data are available on heart function in chronic testosterone deficiency and on the effect of estrogen treatment. Eighteen 4-week-old male Lewis rats were randomly divided into 3 groups (n = 6): 1 group of sham-operated rats and 2 groups of castrated rats. Sixty-six weeks after surgery, 1 castrated group received a dose of 17ß-estradiol (10 µg/kg per day) and the remaining 2 groups received a placebo subcutaneously for 14 days. Left ventricular (LV) systolic and diastolic functions were measured by transthoracic echocardiography. Castration decreased LV ejection fraction (9%) and fractional shortening (15%) and deteriorated LV diastolic function (94%). 17ß-Estradiol treatment increased LV ejection fraction (15%) and fractional shortening (31%) and improved LV diastolic function (48%). Plasma testosterone concentrations were decreased in both castrated groups. In conclusion, chronic testosterone deficiency induced LV systolic and diastolic dysfunction; these disorders were reversed by short-term treatment with 17ß-estradiol.

Oxidative and carbonyl stress in pregnant women with obstructive sleep apnea.

PURPOSE: Pregnant women are particularly susceptible to sleep-disordered breathing. Obstructive sleep apnea (OSA) in pregnancy is associated with poor pregnancy and fetal outcomes. Oxidative stress caused by intermittent hypoxemia and reoxygenation may impact pregnancy health. We hypothesize that pregnant women with OSA have a pronounced oxidative stress profile. METHODS: A case-control study was performed to study oxidative stress markers in the serum of pregnant women with or without OSA. Patients with OSA were identified between 2003 and 2009. Contemporaneous controls were pregnant subjects without apnea, gasping, or snoring around the time of delivery. Serum markers of oxidative and carbonyl stress were measured by spectrophotometric/fluorometric methods. Multiple linear regression analysis was used with a model including age, body mass index at delivery, history of diabetes, and gestational age. RESULTS: Serum samples from 23 OSA cases and 41 controls were identified. Advanced oxidation protein products, a marker for oxidative stress, and advanced glycation end products (AGEs), a marker for carbonyl stress, were significantly lower in women with OSA than in controls (p value <0.0001). Total antioxidant capacity was higher in women with OSA in comparison to controls (p value <0.0001). The difference in AGEs remained significant even after adjusting for confounders. CONCLUSION: Contrary to our hypothesis, the results of this study suggest that pregnant women with OSA have higher antioxidant capacity and lower oxidative and carbonyl stress markers compared to controls, suggesting a possible protective effect of intermittent hypoxia. Whether OSA in pregnancy impacts oxidative stress differently than OSA in the general population remains to be confirmed.

Anti-cytokine therapy and plasma DNA in patients with rheumatoid arthritis.

BACKGROUND: Extracellular DNA (ecDNA) is increased in inflammation and it also induces inflammation. In patients with rheumatoid arthritis (RA), plasma ecDNA is higher than in healthy controls. Due to low specificity, it cannot be used for screening, but it might be useful for monitoring and prognosis of therapy success. The effect of treatment with biological disease-modifying antirheumatic drugs (bDMARDs) on plasma ecDNA in RA patients with regards to its subcellular origin has not been analyzed yet. The aim of this study was to describe the effects of bDMARDs on plasma ecDNA and its nuclear (nDNA) and mitochondrial (mtDNA) fractions in patients with RA. METHODS: Plasma samples of 32 patients with RA were collected before, as well as 3 and 6 months after starting the treatment with bDMARDs. Total plasma ecDNA was quantified fluorometrically. The subcellular origin of ecDNA was assessed using real time PCR. Treatment success was monitored using DAS28 and C-reactive protein (CRP). RESULTS: The clinical status of patients improved. Both DAS28 and CRP decreased by 52 and 73% after 3 months of treatment. Plasma ecDNA decreased significantly only after 6 months (by 26%). Real-time PCR showed that both, nDNA and mtDNA decreased by 63 and by 45% after 6 months. CONCLUSION: Treatment with bDMARDs decreases plasma ecDNA of both nuclear and mitochondrial origin. Dynamics of ecDNA is slower than dynamics of standard clinical markers. Therefore, it is likely to be not useful for monitoring of the disease progress, at least for RA.

Oxidative stress in the brain caused by acute kidney injury.

Uremic encephalopathy is a severe complication of renal failure. The underlying pathogenesis is unknown although several mechanisms have been suggested. Renal failure causes oxidative stress leading to cardiovascular complications. It has been suggested as the potential mediator of uremic encephalopathy as well, but it is largely unknown whether brain tissue itself undergoes oxidative damage in uremia. The aim of our experiment was to analyze oxidative stress markers in different brain regions in an animal model of acute kidney injury (AKI). AKI was induced by ischemia-reperfusion injury in male Wistar rats. Urine was collected in metabolic cages after 24 h. Samples of plasma and several brain regions were collected after 48 h. Markers of lipid peroxidation, protein oxidation and total antioxidant capacity were assessed. Renal failure was confirmed by high plasma creatinine, urea and urinary albumin to creatinine ratio. Our data confirmed increased systemic oxidative stress in the AKI group with plasma concentrations of markers of oxidative damage being twice as high compared to the sham-operated control group. No effect was seen in the urine. In the hippocampus, lipid and protein oxidation was higher, while antioxidant capacity was lower in the rats with AKI. Lipid oxidation markers in the frontal cortex were higher by 33%. No differences to controls were found in the cerebellum and hypothalamus. In conclusion, our results indicate that AKI leads to oxidative stress in the brain, especially in the hippocampus and in the frontal cortex. This kidney-brain crosstalk mediated by increased oxidative stress might explain some of the symptoms of uremic encephalopathy. The causes and consequences of oxidative damage observed in the brain during AKI remain to be elucidated.