Risk Factors for Potential Drug-Drug Interactions in Patients on Chronic Peritoneal Dialysis.

INTRODUCTION: The prevalence of potential drug-drug interactions (pDDIs) is becoming a major safety concern, as it has been previously linked to a significant number of adverse drug events and could have serious consequences for patients, including death. This is especially relevant for patients with chronic renal failure, as they are particularly vulnerable to drug-drug interactions. The aim of this study was to evaluate the prevalence and associated factors of pDDIs in patients receiving chronic peritoneal dialysis. METHODS: An observational, cross-sectional study was conducted on consecutive peritoneal dialysis patients attending four tertiary care hospitals for regular monthly examination. The primary outcome was the number of pDDIs identified using Lexicomp. Potential predictors were determined using multiple linear regression. RESULTS: Total number of patients included in the study was 140. The results showed that pDDIs were highly prevalent, especially in patients who use antiarrhythmics (p = 0.001), have diabetes mellitus (p = 0.001), recently started peritoneal dialysis (p = 0.003), or have higher number of prescribed drugs (p < 0.001). Number of prescribed drugs (p < 0.001) remained a significant predictor of high-risk pDDIs in addition to the female gender (p = 0.043). CONCLUSION: Clinicians should be particularly cautious when prescribing multiple medications to high-risk patients, such as peritoneal dialysis patients, to mitigate the risk of drug-drug interactions and associated adverse health outcomes.

The role of melatonin in preventing amiodarone-induced rat liver damage.

Long-term exposure to amiodarone, an antiarrhythmic drug, can induce different organ damage, including liver. Cell damage included by amiodarone is a consequence of mitochondrial damage, reactive oxygen species production, and cell energy depletion leading to programmed cell death. In the present study, hepatoprotective potential of neurohormone melatonin (50 mg/kg/day) was evaluated in a chronic experimental model of liver damage induced by a 4-week application of amiodarone (70 mg/kg/day). The obtained results indicate that amiodarone induces an increase in xanthine oxidase activity, as well as the content of the lipid and protein oxidatively modified products and p53 levels. Microscopic analysis further corroborated the biochemical findings revealing hepatocyte degeneration, apoptosis, and occasional necrosis, with the activation of Kupffer cells. Coadministration of melatonin and amiodaron prevented an increase in certain damage associated parameters, due to its multiple targets. In conclusion, the application of melatonin together with amiodarone prevented an increase in tissue oxidative damage parameters and moderately prevented liver cell apoptosis, indicating that the damage of hepatocytes provoked by amiodarone supersedes the protective properties of melatonin in a given dose.

Biomarker Phenotypes in Heart Failure with Preserved Ejection Fraction Using Hierarchical Clustering-A Pilot Study.

OBJECTIVES: We hypothesized the existence of distinct phenotype-based groups within the very heterogeneous population of patients of heart failure with preserved ejection fraction (HFpEF) and using an unsupervised hierarchical clustering applied to plasma concentration of various biomarkers. We sought to characterize them as "biomarker phenotypes" and to conclude differences in their overall characteristics. SUBJECTS AND METHODS: A cross-sectional study was conducted on 75 patients with HFpEF. An agglomerative hierarchical clustering was performed using the concentrations of cardiac remodeling biomarkers, BNP and cystatin C. RESULTS: According to the obtained heat map of this analysis, we concluded two distinctive biomarker phenotypes within the HFpEF. The "remodeled phenotype" presented with significantly higher concentrations of cardiac remodeling biomarkers and cystatin C (p < 0.001), higher prevalence of myocardial infarction (p = 0.047), STEMI (p = 0.045), atrial fibrillation (p = 0.047) and anemia: lower erythrocytes count (p=0.037), hemoglobin concentration (p = 0.034) and hematocrit (p = 0.046), compared to "non-remodeled phenotype". Echocardiography showed that patients within "remodeled phenotype" had significantly increased parameters of left ventricular remodeling: left ventricular mass index (p < 0.001), left ventricular mass (p = 0.001), diameters of the interventricular septum (p = 0.027) and posterior wall (p = 0.003) and function alterations, intermediate pauses duration >2.0 seconds (p < 0.006). CONCLUSION: Unsupervised hierarchical clustering applied to plasma concentration of various biomarkers in patients with HFpEF enables the identification of two biomarker phenotypes, significantly different in clinical characteristics and cardiac structure and function, whereas one phenotype particularly relates to patients with reduced ejection fraction. These findings imply distinct underlying pathophysiology within a unique cohort of HFpEF.

Factors Associated with Potentially Inappropriate Prescribing in Patients on Peritoneal Dialysis.

INTRODUCTION: Inappropriate prescribing is common in patients with end-stage kidney disease, especially in those over 65 years of age. Our study aimed to reveal potentially inappropriate drug prescribing in patients on peritoneal dialysis (PD) and explore factors associated with this phenomenon. METHODS: The research was designed as an observational, cross-sectional study on a convenient sample of 145 consecutive patients with PD who attended the four tertiary-care hospitals in Serbia. The main outcome was the extent of inappropriate prescribing, as assessed by the medication appropriateness index, and potential predictors were tested by multiple linear regression. RESULTS: Inappropriate prescribing was a widespread phenomenon among patients on PD. The main factors that promote inappropriate prescribing in this subgroup of patients on kidney replacement therapy are comorbidities (p = 0.000), increased body weight (p = 0.022), a number of prescribed drugs (p = 0.000), and arterial hypertension on examination (p = 0.030). On the other hand, drinking alcohol and higher systolic blood pressure were associated with a lower inappropriate prescribing. CONCLUSION: In order to prevent the occurrence of inappropriate prescribing and its severe health or economic consequences, clinicians should pay special attention when prescribing new drugs to high-risk patients.

Erythropoietin Resistance Development in Hemodialysis Patients: The Role of Oxidative Stress.

Oxidative stress (OS) is considered a significant risk factor for the development of anemia in patients treated by regular hemodialysis (HD). Moreover, OS represents a risk factor for the development of erythropoietin (EPO) resistance in these patients. The aim of this study was to examine the role of OS regarding EPO resistance development in patients treated by regular HD. 96 patients treated with standard HD and on-line hemodiafiltration were included in this study. The patients were treated with short-acting and long-acting EPOs for anemia. The concentration of superoxide anion radical, hydrogen peroxide, thiobarbituric acid reactive substances, and nitric oxide in the form of nitrites and the activity of catalase, superoxide dismutase and reduced glutathione were measured in patients' blood spectrophotometrically. Standard biochemical analysis, inflammatory markers, nutritional status, HD parameters, and erythropoietin resistance index were also determined. Patients with resistance to short-acting EPO had significantly lower concentration of hemoglobin in the blood and hematocrit value, a significantly higher serum ferritin concentration, and significantly lower catalase activity in erythrocytes than patients without EPO resistance. Patients with resistance to long-acting EPO have a significantly lower hemoglobin concentration in the blood, hematocrit values, and serum concentration of prealbumin and vitamin D, as well as significantly higher concentration of C-reactive protein, superoxide anion, and hydrogen peroxide concentration than those without resistance. OS significantly contributes to EPO resistance development. OS, higher ferritin and CRP levels, lower hemoglobin, hematocrit and prealbumin levels, and vitamin D deficiency represent significant risk factors for EPO resistance development in HD patients.

A Retrospective Comparative Study of Serbian Underground Coalmining Injuries.

BACKGROUND: During 2011, a study was undertaken to assess safety conditions in Serbian underground coalmines by analysis of injury data. The study covered all Serbian coalmines, identified week spots from the aspect of safety, and recommended possible courses of action. Since then, Serbia has made changes to safety and health legislation; all coalmines introduced new preventive measures, adopted international standards, and made procedures for risk management. After 10 years a new study has been performed to analyze the impact of these changes. MATERIALS AND METHODS: In this study, the injuries that have occurred in the Serbian underground coal mines over the last 20 years were analyzed. Statistical data analysis was performed by IBM SPSS Statistics v23. The injuries that occurred in the last ten years were compared with the results of the previous study (2000-2009). The average values of injury rates for both periods were compared for each of the categories (severity, age, body part, qualification), and the results were presented as absolute difference or percentile difference. RESULTS: The results showed reduction in the number of injuries in the category of 20-30 years old workers, where the new training procedures for workers, which were set by mandatory legal regulations, certainly contributed. They also showed an increase in the number of injuries in the category of old workers, which indicates that the law did not have a positive effect on this category. CONCLUSION: The total number of injuries is still high; therefore, it is necessary to introduce mechanization and automation in mines and have a better policy for older workers who retire later nowadays.

Characterization of a lytic polysaccharide monooxygenase from Aspergillus fumigatus shows functional variation among family AA11 fungal LPMOs.

The discovery of oxidative cleavage of recalcitrant polysaccharides by lytic polysaccharide monooxygenases (LPMOs) has affected the study and industrial application of enzymatic biomass processing. Despite being widespread in fungi, LPMOs belonging to the auxiliary activity (AA) family AA11 have been understudied. While these LPMOs are considered chitin active, some family members have little or no activity toward chitin, and the only available crystal structure of an AA11 LPMO lacks features found in bacterial chitin-active AA10 LPMOs. Here, we report structural and functional characteristics of a single-domain AA11 LPMO from Aspergillus fumigatus, AfAA11A. The crystal structure shows a substrate-binding surface with features resembling those of known chitin-active LPMOs. Indeed, despite the absence of a carbohydrate-binding module, AfAA11A has considerable affinity for α-chitin and, more so, ß-chitin. AfAA11A is active toward both these chitin allomorphs and enhances chitin degradation by an endoacting chitinase, in particular for α-chitin. The catalytic activity of AfAA11A on chitin increases when supplying reactions with hydrogen peroxide, showing that, like LPMOs from other families, AfAA11A has peroxygenase activity. These results show that, in stark contrast to the previously characterized AfAA11B from the same organism, AfAA11A likely plays a role in fungal chitin turnover. Thus, members of the hitherto rather enigmatic family of AA11 LPMOs show considerable structural and functional differences and may have multiple roles in fungal physiology.

Quantifying Oxidation of Cellulose-Associated Glucuronoxylan by Two Lytic Polysaccharide Monooxygenases from Neurospora crassa.

Family AA9 lytic polysaccharide monooxygenases (LPMOs) are abundant in fungi, where they catalyze oxidative depolymerization of recalcitrant plant biomass. These AA9 LPMOs cleave cellulose and some also act on hemicelluloses, primarily other (substituted) ß-(1→4)-glucans. Oxidative cleavage of xylan has been shown for only a few AA9 LPMOs, and it remains unclear whether this activity is a minor side reaction or primary function. Here, we show that Neurospora crassa LPMO9F (NcLPMO9F) and the phylogenetically related, hitherto uncharacterized NcLPMO9L from N. crassa are active on both cellulose and cellulose-associated glucuronoxylan but not on glucuronoxylan alone. A newly developed method for simultaneous quantification of xylan-derived and cellulose-derived oxidized products showed that NcLPMO9F preferentially cleaves xylan when acting on a cellulose-beechwood glucuronoxylan mixture, yielding about three times more xylan-derived than cellulose-derived oxidized products. Interestingly, under similar conditions, NcLPMO9L and the previously characterized McLPMO9H, from Malbranchea cinnamomea, showed different xylan-to-cellulose preferences, giving oxidized product ratios of about 0.5:1 and 1:1, respectively, indicative of functional variation among xylan-active LPMOs. Phylogenetic and structural analysis of xylan-active AA9 LPMOs led to the identification of characteristic structural features, including unique features that do not occur in phylogenetically remote AA9 LPMOs, such as four AA9 LPMOs whose lack of activity toward glucuronoxylan was demonstrated in the present study. Taken together, the results provide a path toward discovery of additional xylan-active LPMOs and show that the huge family of AA9 LPMOs has members that preferentially act on xylan. These findings shed new light on the biological role and industrial potential of these fascinating enzymes. IMPORTANCE Plant cell wall polysaccharides are highly resilient to depolymerization by hydrolytic enzymes, partly due to cellulose chains being tightly packed in microfibrils that are covered by hemicelluloses. Lytic polysaccharide monooxygenases (LPMOs) seem well suited to attack these resilient copolymeric structures, but the occurrence and importance of hemicellulolytic activity among LPMOs remain unclear. Here, we show that certain AA9 LPMOs preferentially cleave xylan when acting on a cellulose-glucuronoxylan mixture, and that this ability is the result of protein evolution that has resulted in a clade of AA9 LPMOs with specific structural features. Our findings strengthen the notion that the vast arsenal of AA9 LPMOs in certain fungal species provides functional versatility and that AA9 LPMOs may have evolved to promote oxidative depolymerization of a wide variety of recalcitrant, copolymeric plant polysaccharide structures. These findings have implications for understanding the biological roles and industrial potential of LPMOs.

Kinetic Characterization of a Putatively Chitin-Active LPMO Reveals a Preference for Soluble Substrates and Absence of Monooxygenase Activity.

Enzymes known as lytic polysaccharide monooxygenases (LPMOs) are recognized as important contributors to aerobic enzymatic degradation of recalcitrant polysaccharides such as chitin and cellulose. LPMOs are remarkably abundant in nature, with some fungal species possessing more than 50 LPMO genes, and the biological implications of this diversity remain enigmatic. For example, chitin-active LPMOs have been encountered in biological niches where chitin conversion does not seem to take place. We have carried out an in-depth kinetic characterization of a putatively chitin-active LPMO from Aspergillus fumigatus (AfAA11B), which, as we show here, has multiple unusual properties, such as a low redox potential and high oxidase activity. Furthermore, AfAA11B is hardly active on chitin, while being very active on soluble oligomers of N-acetylglucosamine. In the presence of chitotetraose, the enzyme can withstand considerable amounts of H2O2, which it uses to efficiently and stoichiometrically convert this substrate. The unique properties of AfAA11B allowed experiments showing that it is a strict peroxygenase and does not catalyze a monooxygenase reaction. This study shows that nature uses LPMOs for breaking glycosidic bonds in non-polymeric substrates in reactions that depend on H2O2. The quest for the true substrates of these enzymes, possibly carbohydrates in the cell wall of the fungus or its competitors, will be of major interest.

The Discriminatory Ability of Renalase and Biomarkers of Cardiac Remodeling for the Prediction of Ischemia in Chronic Heart Failure Patients With the Regard to the Ejection Fraction.

Background: Renalase has been implicated in chronic heart failure (CHF); however, nothing is known about renalase discriminatory ability and prognostic evaluation. The aims of the study were to assess whether plasma renalase may be validated as a predictor of ischemia in CHF patients stratified to the left ventricular ejection fraction (LVEF) and to determine its discriminatory ability coupled with biomarkers representing a range of heart failure (HF) pathophysiology: brain natriuretic peptide (BNP), soluble suppressor of tumorigenicity (sST2), galectin-3, growth differentiation factor 15 (GDF-15), syndecan-1, and cystatin C. Methods: A total of 77 CHF patients were stratified according to the LVEF and were subjected to exercise stress testing. Receiver operating characteristic curves were constructed, and the areas under curves (AUC) were determined, whereas the calibration was evaluated using the Hosmer-Lemeshow statistic. A DeLong test was performed to compare the AUCs of biomarkers. Results: Independent predictors for ischemia in the total HF cohort were increased plasma concentrations: BNP (p = 0.008), renalase (p = 0.012), sST2 (p = 0.020), galectin-3 (p = 0.018), GDF-15 (p = 0.034), and syndecan-1 (p = 0.024), whereas after adjustments, only BNP (p = 0.010) demonstrated predictive power. In patients with LVEF <45% (HFrEF), independent predictors of ischemia were BNP (p = 0.001), renalase (p < 0.001), sST2 (p = 0.004), galectin-3 (p = 0.003), GDF-15 (p = 0.001), and syndecan-1 (p < 0.001). The AUC of BNP (0.837) was statistically higher compared to those of sST2 (DeLong test: p = 0.042), syndecan-1 (DeLong: p = 0.022), and cystatin C (DeLong: p = 0.022). The AUCs of renalase (0.753), galectin-3 (0.726), and GDF-15 (0.735) were similar and were non-inferior compared to BNP, regarding ischemia prediction. In HFrEF patients, the AUC of BNP (0.980) was statistically higher compared to those of renalase (DeLong: p < 0.001), sST2 (DeLong: p < 0.004), galectin-3 (DeLong: p < 0.001), GDF-15 (DeLong: p = 0.001), syndecan-1 (DeLong: p = 0.009), and cystatin C (DeLong: p = 0.001). The AUC of renalase (0.814) was statistically higher compared to those of galectin-3 (DeLong: p = 0.014) and GDF-15 (DeLong: p = 0.046) and similar to that of sST2. No significant results were obtained in the patients with LVEF >45%. Conclusion: Plasma renalase concentration provided significant discrimination for the prediction of ischemia in patients with CHF and appeared to have similar discriminatory potential to that of BNP. Although further confirmatory studies are warranted, renalase seems to be a relevant biomarker for ischemia prediction, implying its potential contribution to ischemia-risk stratification.

Standardized Aronia melanocarpa extract regulates redox status in patients receiving hemodialysis with anemia.

The aim of our study was to investigate the effects of one-month consumption of polyphenol-rich standardized Aronia melanocarpa extract (SAE) on redox status in anemic hemodialysis patients. The study included 30 patients (Hb < 110 g/l, hemodialysis or hemodiafiltration > 3 months; > 3 times week). Patients were treated with commercially available SAE in a dose of 30 ml/day, for 30 days. After finishing the treatment blood samples were taken to evaluate the effects of SAE on redox status. Several parameters of anemia and inflammation were also followed. After the completion of the treatment, the levels of superoxide anion radical and nitrites significantly dropped, while the antioxidant capacity improved via elevation of catalase and reduced glutathione. Proven antioxidant effect was followed by beneficial effects on anemia parameters (increased hemoglobin and haptoglobin concentration, decreased ferritin and lactate dehydrogenase concentration), but SAE consumption didn't improve inflammatory status, except for minor decrease in C-reactive protein. The consumption of SAE regulates redox status (reduce the productions of pro-oxidative molecules and increase antioxidant defense) and has beneficial effects on anemia parameters. SAE could be considered as supportive therapy in patients receiving hemodialysis which are prone to oxidative stress caused by both chronic kidney disease and hemodialysis procedure. Additionally, it could potentially be a good choice for supplementation of anemic hemodialysis patients. TRN: NCT04208451 December 23, 2019 "retrospectively registered".

Does HAS-BLED risk score underestimate the risk of bleeding in patients with triple antithrombotic therapy?

stroke or other thromboembolic complications in patients with atrial fibrillation (AF). On the other hand, dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) represents a cornerstone in the treatment of acute coronary syndrome. Atrial fibrillation is relatively common in patients with coronary artery disease and patients who undergo primary percutaneous coronary interventions (PCI) with stent implantation. They should be on triple antithrombotic therapy (TAT): preferably direct oral anticoagulants (DOAC) plus aspirin plus clopidogrel as it prevents ischemic as well as thromboembolic events. Before introducing OAT in patients with AF we must assess the risk of future bleeding episodes as OAT can lead to some life-threatening bleeding events. The most common risk score used for that purpose is HASBLED score. HAS-BLED score is valuable, proven tool in assessing future bleeding events in patients with AF. Nevertheless, it does not make the difference between dual and triple antithrombotic therapy which can be of great importance in preventing bleeding events.

Characterization of two family AA9 LPMOs from Aspergillus tamarii with distinct activities on xyloglucan reveals structural differences linked to cleavage specificity.

Aspergillus tamarii grows abundantly in naturally composting waste fibers of the textile industry and has a great potential in biomass decomposition. Amongst the key (hemi)cellulose-active enzymes in the secretomes of biomass-degrading fungi are the lytic polysaccharide monooxygenases (LPMOs). By catalyzing oxidative cleavage of glycoside bonds, LPMOs promote the activity of other lignocellulose-degrading enzymes. Here, we analyzed the catalytic potential of two of the seven AA9-type LPMOs that were detected in recently published transcriptome data for A. tamarii, namely AtAA9A and AtAA9B. Analysis of products generated from cellulose revealed that AtAA9A is a C4-oxidizing enzyme, whereas AtAA9B yielded a mixture of C1- and C4-oxidized products. AtAA9A was also active on cellopentaose and cellohexaose. Both enzymes also cleaved the ß-(1→4)-glucan backbone of tamarind xyloglucan, but with different cleavage patterns. AtAA9A cleaved the xyloglucan backbone only next to unsubstituted glucosyl units, whereas AtAA9B yielded product profiles indicating that it can cleave the xyloglucan backbone irrespective of substitutions. Building on these new results and on the expanding catalog of xyloglucan- and oligosaccharide-active AA9 LPMOs, we discuss possible structural properties that could underlie the observed functional differences. The results corroborate evidence that filamentous fungi have evolved AA9 LPMOs with distinct substrate specificities and regioselectivities, which likely have complementary functions during biomass degradation.

Analysis of fatal injuries in Serbian underground coal mines - 50 years review.

The study presented here analyzes mining accidents and fatal injuries in Serbian underground coal mines over a period of 50 years, in order to assess the effectiveness of legislation changes in the overall safety of work environment. Two distinct periods, prior to 2000 and after 2000 were compared. The data from the period after 2000 were further analyzed to provide better understanding of the results. In order to assess the overall state of safety in Serbian mines, the data on fatal injuries were also compared to the international data. It was found that the legislative changes are more easily accepted by the common workers than by the mine management. Consequently, the key recommendation for the safety of coal mine companies in Serbia is the investment in the new technology. Additionally, mine management should be in the focus of the mining inspection with a stronger penal policy regarding mine safety neglect.

Cardiac Remodeling Biomarkers as Potential Circulating Markers of Left Ventricular Hypertrophy in Heart Failure with Preserved Ejection Fraction.

Soluble suppressor of tumorigenicity 2 (sST2), galectin-3, growth differentiation factor (GDF)-15 and syndecan-1 represent biomarkers of cardiac remodeling, involved in heart failure (HF) progression. We hypothesize that their plasma concentrations, together with brain natriuretic peptide (BNP), are different in HF stratified by ejection fraction (EF), demonstrating correlations with echocardiographic parameters that indicate left ventricular (LV) hypertrophy; LV mass index (LVMI) and posterior wall and septum diameters. HF patients (n = 77) were classified according to EF: reduced EF < 40% (HFrEF), mid-range EF = 40-49% (HFmrEF), preserved EF > 50% (HFpEF). We found that plasma concentrations of four cardiac remodeling biomarkers were highest in HFrEF and lowest in HFpEF, p < 0.001. In HFpEF, remodeling biomarkers independently correlated with LVMI: sST2 (p = 0. 002), galectin-3 (p < 0.001), GDF-15 (p = 0.011), and syndecan-1 (p = 0.006), whereas galectin-3 correlated after multivariable adjustments (p = 0.001). Independent correlates of septum and posterior wall diameters, in HFpEF, were sST2 (p = 0.019; p = 0.026), galectin-3 (p = 0.011; p = 0.009), GDF-15 (p = 0.007; p = 0.001), and syndecan-1 (p = 0.005; p = 0.002). In HFrEF, only sST2, adjusted, correlated with LVMI (p = 0.010), whereas BNP correlated with LVMI (p = 0.002) and EF (p = 0.001). GDF-15 correlated with diastolic dysfunction in HFpEF (p = 0.046) and HFrEF (p = 0.024). Cardiac remodeling biomarkers are potential circulating indicators of LV hypertrophy in HFpEF, which may ensure timely recognition of disease progression among high-risk patients.

The partnership between renalase and ejection fraction as a risk factor for increased cardiac remodeling biomarkers in chronic heart failure patients.

Objective: Heart failure (HF) represents a huge socio-economic burden. It has been demonstrated, experimentally, that renalase, a newly discovered protein, prevents cardiac hypertrophy and adverse remodeling, which is seen in HF. We postulated the following aims: to investigate associations of renalase with biomarkers of cardiac remodeling: galectin-3, soluble suppression of tumorigenicity, (sST2), growth differentiation factor 15 (GDF-15) and syndecan-1, myocardial stretch (BNP) and cardio-renal axis (cystatin C) in HF patients with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) to determine whether renalase, in combination with left ventricular ejection fraction (LVEF), represents a risk factor for plasma elevation in biomarkers.Methods: We classified HF patients (n = 76) according to LVEF (preserved/reduced), applied a median plasma renalase (113 ng/mL) as a cut-off value (low/high) and created four subgroups of HF patients: HFpEF/low renalase (n = 19), HFrEF/low renalase (n = 19), HFrEF/high renalase (n = 32) and HFpEF/high renalase (n = 6). A control group (n = 35) consisted of healthy volunteers.Results: Plasma concentrations of evaluated biomarkers were determined using an ELISA technique and were highest in HF patients with reduced EF (p < .001, respectively), and renalase's positive correlations were obtained relating to all biomarkers: galectin-3 (r = 0.913; p < .001), sST2 (r = 0.965; p < .001), GDF-15 (r = 0.887; p < .001), syndecan-1 (r = 0.922; p < .001), BNP (r = 0.527; p < .001) and cystatin C (r = 0.844; p < .001) and strong and negative correlation with LVEF (r = -0.456, p < .001). Increased renalase, regardless of the EF (preserved/reduced), was shown to be an independent risk factor for an increase in all evaluated cardiac remodeling biomarkers, p < .001, respectively. However, increased renalase and reduced EF was the only independent risk factor for BNP and cystatin C elevation, p < .001, respectively. Results after multivariable adjustments (age/gender) were identical.Conclusion: When elevated plasma renalase and HF are present, regardless of EF being reduced or preserved, that represents a significant risk factor for increase in cardiac remodeling biomarker plasma concentrations. However, only elevated renalase and reduced EF demonstrated significance as a risk factor for BNP and cystatin C plasma elevation. Renalase may be considered a promising molecule for the improved predictive abilities of conventional biomarkers and is worthy of further investigation.

The influence of folic acid-induced acute kidney injury on cardiac function and redox status in rats.

The aim of this study was to evaluate the influence of acute kidney injury caused by high doses of folic acid on cardiac function and markers of oxidative stress in serum and isolated rat heart. Isolated hearts of Wistar albino rats (divided into two groups: control and folic acid group) were perfused according to Langendorff technique at basal coronary perfusion pressure CPP of 70 cm H2O. After a stabilization period, CPP was lowered to 60 cm H2O and then gradually increased to 80, 100, 120 and finally decreased to 40 cm H2O in order to establish coronary autoregulation. For each perfusion pressure value, the left ventricular function parameters were determined. Samples of coronary venous effluent were collected for determination of coronary flow and biomarkers of oxidative stress. The blood samples were collected in order to examine the values of serum urea, creatinine, Na, K, and parameters of oxidative stress and antioxidant defense system. Heart and kidney tissue samples were collected for histopathological examination. Folic acid group showed reduction of systolic and diastolic left ventricular pressure and increase of coronary flow and minimum left ventricular pressure development rate. In coronary flow, folic acid group showed increased levels of TBARS and reduction of H2O2 and NO2-. Serum ROS concentrations were lower in rats treated with folic acid, particularly levels of TBARS and NO2- in which values were significantly lower. The parameters of systemic antioxidative stress were at significantly high levels especially SOD and GSH. This study is the experimental confirmation of cardio-renal syndrome type 3, which represents the acute kidney injury that causes a damage of a heart function. The data suggest that negative effects of acute kidney injury on myocardium do not necessarily involve oxidative stress, which may lead to future investigations which will be based on inflammation as a one of the important factors in the organ crosstalk.

Association of Plasma Renalase and Left Ventricle Mass Index in Heart Failure Patients Stratified to the Category of the Ejection Fraction: A Pilot Study.

Heart failure represents a growing health problem, with increasing morbidity and mortality globally. According to the mechanisms involved in the pathogenesis of heart failure, many biomarkers have been proposed for the timely diagnosis and prognostication of patients with heart failure, but other than natriuretic peptides, none of them has gained enough clinical significance. Renalase, a new protein derived from kidneys was demonstrated to metabolize catecholamines and to have a cardioprotective role. The aim of the study was to determine whether renalase and brain natriuretic peptide (BNP) concentration could be used to differentiate heart failure patients stratified to the category of the ejection fraction and whether plasma renalase could be used as a biomarker for left ventricle hypertrophy in all subgroups of heart failure patients. We included patients diagnosed with heart failure and stratified them to the three subgroups according to the ejection fraction. Regarding echocardiographic parameters, HFmrEF had an intermediate profile in between HFrEF and HFpEF, with statistical significance in most evaluated parameters. BNP concentration was significantly different in all three subgroups (p < 0.001), and renalase was statistically higher in HFrEF (p = 0.007) compared to the HFmrEF and HFpEF, where its results were similar, without statistical significance. Renalase plasma concentration was demonstrated to be highly and positively associated with left ventricle mass index in HFrEF (p = 0.029), as well as increased plasma concentration of BNP (p = 0.006). In the HFmrEF group of patients, body mass index was positively associated with LVMI (p = 0.05), while in the patients with HFpEF, diabetes mellitus was demonstrated to have a positive association with LVMI (p = 0.043). These findings suggest that renalase concentration may be measured in order to differentiate patients with reduced ejection fraction. Plasma renalase concentrations positively correlated with left ventricle hypertrophy in patients with reduced ejection fraction, being strongly associated with increased left ventricular mass index.

Specific Xylan Activity Revealed for AA9 Lytic Polysaccharide Monooxygenases of the Thermophilic Fungus Malbranchea cinnamomea by Functional Characterization.

The thermophilic biomass-degrader Malbranchea cinnamomea exhibits poor growth on cellulose but excellent growth on hemicelluloses as the sole carbon source. This is surprising considering that its genome encodes eight lytic polysaccharide monooxygenases (LPMOs) from auxiliary activity family 9 (AA9), enzymes known for their high potential in accelerating cellulose depolymerization. We characterized four of the eight (M. cinnamomea AA9s) McAA9s, namely, McAA9A, McAA9B, McAA9F, and McAA9H, to gain a deeper understanding about their roles in the fungus. The characterized McAA9s were active on hemicelluloses, including xylan, glucomannan, and xyloglucan, and furthermore, in accordance with transcriptomics data, differed in substrate specificity. Of the McAA9s, McAA9H is unique, as it preferentially cleaves residual xylan in phosphoric acid-swollen cellulose (PASC). Moreover, when exposed to cellulose-xylan blends, McAA9H shows a preference for xylan and for releasing (oxidized) xylooligosaccharides. The cellulose dependence of the xylan activity suggests that a flat conformation, with rigidity similar to that of cellulose microfibrils, is a prerequisite for productive interaction between xylan and the catalytic surface of the LPMO. McAA9H showed a similar trend on xyloglucan, underpinning the suggestion that LPMO activity on hemicelluloses strongly depends on the polymers' physicochemical context and conformation. Our results support the notion that LPMO multiplicity in fungal genomes relates to the large variety of copolymeric polysaccharide arrangements occurring in the plant cell wall.IMPORTANCE The Malbranchea cinnamomea LPMOs (McAA9s) showed activity on a broad range of soluble and insoluble substrates, suggesting their involvement in various steps of biomass degradation besides cellulose decomposition. Our results indicate that the fungal AA9 family is more diverse than originally thought and able to degrade almost any kind of plant cell wall polysaccharide. The discovery of an AA9 that preferentially cleaves xylan enhances our understanding of the physiological roles of LPMOs and enables the use of xylan-specific LPMOs in future applications.

Comparison of three seemingly similar lytic polysaccharide monooxygenases from Neurospora crassa suggests different roles in plant biomass degradation.

Many fungi produce multiple lytic polysaccharide monooxygenases (LPMOs) with seemingly similar functions, but the biological reason for this multiplicity remains unknown. To address this question, here we carried out comparative structural and functional characterizations of three cellulose-active C4-oxidizing family AA9 LPMOs from the fungus Neurospora crassa, NcLPMO9A (NCU02240), NcLPMO9C (NCU02916), and NcLPMO9D (NCU01050). We solved the three-dimensional structure of copper-bound NcLPMO9A at 1.6-Å resolution and found that NcLPMO9A and NcLPMO9C, containing a CBM1 carbohydrate-binding module, bind cellulose more strongly and were less susceptible to inactivation than NcLPMO9D, which lacks a CBM. All three LPMOs were active on tamarind xyloglucan and konjac glucomannan, generating similar products but clearly differing in activity levels. Importantly, in some cases, the addition of phosphoric acid-swollen cellulose (PASC) had a major effect on activity: NcLPMO9A was active on xyloglucan only in the presence of PASC, and PASC enhanced NcLPMO9D activity on glucomannan. Interestingly, the three enzymes also exhibited large differences in their interactions with enzymatic electron donors, which could reflect that they are optimized to act with different reducing partners. All three enzymes efficiently used H2O2 as a cosubstrate, yielding product profiles identical to those obtained in O2-driven reactions with PASC, xyloglucan, or glucomannan. Our results indicate that seemingly similar LPMOs act preferentially on different types of copolymeric substructures in the plant cell wall, possibly because these LPMOs are functionally adapted to distinct niches differing in the types of available reductants.