Oxidative stress and dysregulation of superoxide dismutase and NADPH oxidase in renal insufficiency

Moringa oleifera leaves extract loaded gold nanoparticles offers a promising approach in protecting against experimental nephrotoxicity

Cisplatin is one of the most important antitumor drugs, however; it has numerous adverse effects like nephrotoxicity which is considered one of cisplatin uses . The study was planned to evaluate the nephroprotective effect of M. oleifera leaves extract loaded gold nanoparticles (Au-NPs) against cisplatin-induced nephrotoxicity in rats. Initially, total phenolic contents (TPC) and the antioxidant activity of the M. oleifera leaves extract were evaluated and recorded 8.50 mg/g and 39.89 % respectively. After that, the dry leaves of M. oleifera were grinded into fine powder and extracted using water extraction system. Then, different volumes (0.5, 1 and 2 mL) of M. Oleifera were blended with constant volume of Au-NPs (1 mL). Both Au-NPs and M. oleifera extract loaded Au-NPs were investigated using transmission electron microscope (TEM) that illustrated the deposition of M. Oleifera onto Au-NPs. The experimental study was performed on seventy male albino rats alienated into seven groups. Group I healthy rats, group II injected with one dose of cisplatin (CisPt), groups from III to VII treated groups received CisPt then received M. Oleifera leaves extract alone and /or Au-NPs with different ratios and concentrations. After the experiment' time, serum urea and creatinine, kidney injury molecule-1 (KIM-1), advanced oxidation protein products (AOPP), monocyte chemoattractant protein-1 (MCP-1), tumor necrotic factor-α (TNF-α), and interleukin-6 (IL-6) were evaluated as markers of renal nephrotoxicity. The kidneys of rats were excised for malondialdehyde (MDA), nitric oxide (NO), and superoxide dismutase (SOD) assessments. Induction of CisPt showed a highly significant disturbance in oxidant/anti-oxidant balance and inducing inflammatory cascades supporting nephrotoxicity, while treatment with M. Oleifera leaves extract, Au-NPs, and the different concentrations of the extract loaded on Au-NPs had a crucial role in attenuating oxidative stress, enhancing antioxidant systems, and reducing inflammatory biomarkers, although the most significant results showed a powerful scavenging activity against nephrotoxicity induced by CisPt was obtained with M. Oleifera leaves extract loaded on Au-NPs with a concentration of 2:1 respectively.

N-Acetylcysteine Alleviates the Progression of Chronic Kidney Disease: A Three-Year Cohort Study

Background and Objectives: The prevalence of chronic kidney disease (CKD) is approximately 10% of the population in many countries. CKD progresses to end-stage renal disease (ESRD), resulting in adverse outcomes, prolonged hospitalization, and increased healthcare costs. Therefore, reducing CKD progression to ESRD is recognized as an important health issue. Materials and Methods: Data from the study participants with stage 3 to stage 5 CKD (n = 7668) were collected from the National Health Insurance (NHI) program in Taiwan (1 November 2014 to 31 December 2020). CKD patients who had ingested or not ingested N-acetylcysteine (NAC) for three years were divided into the study group (NAC users; n = 165) and the control group (NAC non-users; n = 165) to explore whether NAC use could alleviate CKD progression and reduce the risks associated with hemodialysis in CKD patients. Results: The levels of serum creatinine (SCr) and estimated globular filtration rate (eGFR) were nearly unchanged and/or slightly changed in NAC users, but the SCr levels were slightly increased, and the eGFR levels were significantly decreased in NAC non-users at the six-month interval during the three years. A statistical difference was observed between the two groups for both levels from 12 months to 36 months. The incidence rate of hemodialysis was significantly lower in NAC users than in non-NAC users (4.8% vs. 12.7%, Wald test = 5.947, p = 0.015, OR = 34.9). These results indicated that NAC use may improve renal function of CKD patients by modulating SCr and eGFR and, in turn, reducing the risk of hemodialysis. Conclusions: We investigated whether NAC could be used to reduce CKD progression to ESRD. For the three-year retrospective study, the incidence rate of hemodialysis was significantly lower in NAC users than in non-NAC users via modulating SCr and eGRF levels. NAC use might be a useful clinical approach for reducing CKD progression to ESRD.

Differential Modulation of Markers of Oxidative Stress and DNA Damage in Arterial Hypertension

Patients with arterial hypertension have an increased risk of developing tumors, particularly renal cell carcinoma. Arterial hypertension is linked to DNA damage via the generation of oxidative stress, in which an upregulated renin-angiotensin-aldosterone system plays a crucial role. The current study investigated surrogates of oxidative stress and DNA damage in a group of hypertensive patients (HypAll, n = 64) and subgroups of well (HypWell, n = 36) and poorly (HypPoor, n = 28) controlled hypertensive patients compared to healthy controls (n = 8). In addition, a longitudinal analysis was performed with some of the hypertensive patients. Markers for oxidative stress in plasma (SHp, D-ROM, and 3-nitrotyrosine) and urine (8-oxodG, 15-F2t-isoprostane, and malondialdehyde) and markers for DNA damage in lymphocytes (γ-H2AX and micronuclei) were measured. In HypAll, all markers of oxidative stress except malondialdehyde were increased compared to the controls. After adjustment for age, this association was maintained for the protein stress markers SHp and 3-nitrotyrosine. With regard to the markers for DNA damage, there was no difference between HypAll and the controls. Further, no significant differences became apparent in the levels of both oxidative stress and DNA damage between HypWell and HypPoor. Finally, a positive correlation between the development of blood pressure and oxidative stress was observed in the longitudinal study based on the changes in D-ROM and systolic blood pressure. In conclusion, we found increased oxidative stress in extensively treated hypertensive patients correlating with the level of blood-pressure control but no association with DNA damage.

Fibroblast Growth Factor 23 and Muscle Wasting: A Metabolic Point of View

Protein energy wasting (PEW), mostly characterized by decreased body stores of protein and energy sources, particularly in the skeletal muscle compartment, is highly prevalent in patients with moderate to advanced chronic kidney disease (CKD). Fibroblast growth factor 23 (FGF23) is an endocrine hormone secreted from bone and has systemic actions on skeletal muscle. In CKD, FGF23 is elevated and its coreceptor α-klotho is suppressed. Multiple lines of evidence suggest that FGF23 is interconnected with various mechanisms of skeletal muscle wasting in CKD, including systemic and local inflammation, exaggerated oxidative stress, insulin resistance (IR), and abnormalities in adipocytokine metabolism. Investigation of metabolic actions of FGF23 on muscle tissue could provide new insights into metabolic and nutritional abnormalities observed in patients with CKD.

Renal fibrosis in type 2 cardiorenal syndrome: An update on mechanisms and therapeutic opportunities

Cardiorenal syndrome (CRS) is a state of coexisting heart failure and renal insufficiency in which acute or chronic dysfunction of the heart or kidney lead to acute or chronic dysfunction of the other organ.It was found that renal fibrosis is an important pathological process in the progression of type 2 CRS to end-stage renal disease, and progressive renal impairment accelerates the deterioration of cardiac function and significantly increases the hospitalization and mortality rates of patients. Previous studies have found that Hemodynamic Aiteration, RAAS Overactivation, SNS Dysfunction, Endothelial Dysfunction and Imbalance of natriuretic peptide system contribute to the development of renal disease in the decompensated phase of heart failure, but the exact mechanisms is not clear. Therefore, in this review, we focus on the molecular pathways involved in the development of renal fibrosis due to heart failure and identify the canonical and non-canonical TGF-β signaling pathways and hypoxia-sensing pathways, oxidative stress, endoplasmic reticulum stress, pro-inflammatory cytokines and chemokines as important triggers and regulators of fibrosis development, and summarize the therapeutic approaches for the above signaling pathways, including SB-525334 Sfrp1, DKK1, IMC, rosarostat, 4-PBA, etc. In addition, some potential natural drugs for this disease are also summarized, including SQD4S2, Wogonin, Astragaloside, etc.

Redox Signaling in Chronic Kidney Disease-Associated Cachexia

Redox signaling alterations contribute to chronic kidney disease (CKD)-associated cachexia. This review aims to summarize studies about redox pathophysiology in CKD-associated cachexia and muscle wasting and to discuss potential therapeutic approaches based on antioxidant and anti-inflammatory molecules to restore redox homeostasis. Enzymatic and non-enzymatic systems of antioxidant molecules have been studied in experimental models of kidney diseases and patients with CKD. Oxidative stress is increased by several factors present in CKD, including uremic toxins, inflammation, and metabolic and hormone alterations, leading to muscle wasting. Rehabilitative nutritional and physical exercises have shown beneficial effects for CKD-associated cachexia. Anti-inflammatory molecules have also been tested in experimental models of CKD. The importance of oxidative stress has been shown by experimental studies in which antioxidant therapies ameliorated CKD and its associated complications in the 5/6 nephrectomy model. Treatment of CKD-associated cachexia is a challenge and further studies are necessary to investigate potential therapies involving antioxidant therapy.

Effect of hypoxia and uremia on oxidative stress on erythrocytes from hemodialysis patients

Oxidative stress (OS) is essential in uremia-associated comorbidities, including renal anemia. Complications experienced by hemodialysis (HD) patients, such as hypoxemia and uremic toxins accumulation, induce OS and premature death of red blood cells (RBC). We aimed to characterize reactive oxygen species (ROS) production and antioxidant pathways in HD-RBC and RBC from healthy controls (CON-RBC) and evaluate the role of uremia and hypoxia in these pathways. ROS production, xanthine oxidase (XO) and superoxide dismutase (SOD) activities, glutathione (GSH), and heme oxygenase-1 (HO-1) levels were measured using flow cytometry or spectrophotometry in CON-RBC and HD-RBC (pre- and post-HD), at baseline and after 24 h incubation with uremic serum (S-HD) and/or under hypoxic conditions (5% O₂ ). Ketoprofen was used to inhibit RBC uremic toxins uptake. HD-RBC showed higher ROS levels and lower XO activity than CON-RBC, particularly post-HD. GSH levels were lower, while SOD activity and HO-1 levels of HD-RBC were higher than control. Hypoxia per se triggered ROS production in CON-RBC and HD-RBC. S-HD, on top of hypoxia, increased ROS levels. Inhibition of uremic toxins uptake attenuated ROS of CON and HD-RBC under hypoxia and uremia. CON-RBC in uremia and hypoxia showed lower GSH levels than cells in normoxia and non-uremic conditions. Redox mechanisms of HD-RBC are altered and prone to oxidation. Uremic toxins and hypoxia play a role in unbalancing these systems. Hypoxia and uremia participate in the pathogenesis of OS in HD-RBC and might induce RBC death and thus compound anemia.

The Association of Blood Urea Nitrogen to Creatinine Ratio and the Prognosis of Critically Ill Patients with Cerebral Infarction: A Cohort Study

Background

To evaluate the association between blood urea nitrogen (BUN) to creatinine (Cr) (BUN/Cr) ratio and the in-hospital mortality of critically ill patients with cerebral infarction in intensive care unit (ICU).

Methods

In this cohort study, the data of 3059 participants with cerebral infarction were collected from the Medical Information Mart for Intensive Care (MIMIC)-III and the MIMIC-IV database. After propensity score matching (PSM) on age and gender, 2085 people were involved in and divided into the alive group (n = 1390) and the dead group (n = 695) based on the results of follow-up. Multivariate logistic analyses were applied to identify the confounders and the association between BUN/Cr and mortality of cerebral infarction.

Results

The median follow-up time was 10.5 days. Among 2778 participants, 695 were dead at the end of follow-up. Univariate analysis revealed that BUN/Cr [risk ratio (RR) = 1.01, 95% confidence interval (CI): 1.01-1.02] might be associated with the in-hospital mortality of cerebral infarction patients. After adjusting for respiratory failure, malignant cancer, anticoagulation, liver disease, white blood cell (WBC), red cell distribution width (RDW), glucose, bicarbonate, and temperature, BUN/Cr had week correlation with the increased risk of in-hospital mortality of cerebral infarction patients (RR = 1.01, 95% CI: 1.01-1.02).

Conclusion

This study evaluated the association between BUN/Cr and the in-hospital mortality of cerebral infarction patients in ICU and found that BUN/Cr had weak correlation with the increased risk of in-hospital mortality of patients with cerebral infarction in ICU especially in males and those with respiratory failure, malignant cancer, and without liver disease, as well as those receiving anticoagulation.

Evaluated Glomerular Filtration Rate Is Associated With Non-alcoholic Fatty Liver Disease: A 5-Year Longitudinal Cohort Study in Chinese Non-obese People

Objective

Evidence regarding the association between evaluated glomerular filtration rate (eGFR) and non-alcoholic fatty liver disease (NAFLD) is still limited. On that account, the purpose of our research is to survey the link of evaluated eGFR on NAFLD.

Methods

This study is a retrospective cohort study. Which consecutively and non-selectively collected a total of 16,138 non-obese participants in a Chinese hospital from January 2010 to December 2014. We then used the Cox proportional-hazards regression model to explore the relationship between baseline eGFR and NAFLD risk. A Cox proportional hazards regression with cubic spline functions and smooth curve fitting (the cubic spline smoothing) was used to identify the non-linear relationship between eGFR and NAFLD. Additionally, we also performed a series of sensitivity analyses and subgroup analyses. Data had been uploaded to the DATADRYAD website.

Results

The mean age of the included individuals was 43.21 ± 14.95 years old, and 8,467 (52.47%) were male. The mean baseline eGFR was 98.83 ± 22.80 mL/min per 1.73m2. During a median follow-up time of 35.8 months, 2,317 (14.36%) people experienced NAFLD. After adjusting covariates, the results showed that eGFR was negatively associated with incident NAFLD (HR = 0.983, 95%CI: 0.980, 0.985). There was also a non-linear relationship between eGFR and NAFLD, and the inflection point of eGFR was 103.489 mL/min per 1.73 m2. The effect sizes (HR) on the left and right sides of the inflection point were 0.988 (0.984, 0.991) and 0.971 (0.963, 0.979), respectively. And the sensitive analysis demonstrated the robustness of our results. Subgroup analysis showed that eGFR was more strongly associated with incident NAFLD in diastolic blood pressure (DBP) < 90 mmHg, fasting plasma glucose (FPG) ≤ 6.1 mmol/L, high-density lipoprotein cholesterol (HDL-c) < 1 mmol/L, and alanine aminotransferase (ALT) ≥ 40 U/L participants. In contrast, the weaker association was probed in those with DBP ≥ 90 mmHg, ALT < 40 U/L, FPG > 6.1 mmol/L, and HDL-c ≥ 1 mmol/L.

Conclusion

This study demonstrates a negative and non-linear association between eGFR and incident NAFLD in the Chinese non-obese population. eGFR is strongly related to NAFLD when eGFR is above 103 mL/min per 1.73 m2. From a therapeutic perspective, it makes sense to maintain eGFR levels within the inflection point to 130 mL/min/1.73 m2.

ANOM Approach for Statistical Evaluation of Some Antioxidant Enzyme Activities

Free radicals are chemical molecules that are more reactive and have an unpaired electron. Free radicals formed inside the cell oxidize biomolecules, leading to cell death and tissue damage. Antioxidants are molecules that can stabilize or inactivate free radicals before they damage the cell. In this study; the availability of Malondialdehyde, Superoxide dismutase, Catalase and Reduced glutathione levels as markers for related diseases was evaluated by examining whether and in what range they may vary in some diseases. In study, nine groups consist of prostate cancer, cirrhosis, liver transplantation, chronic kidney damage, acute kidney injury, X-ray exposure, CT exposure, MR exposure and Osteonecrosis. Analysis of means is a method developed to compare group means with the overall mean and presents the results graphically in an easy-to-understand manner without the required for any post hoc test. In addition, related characteristics were categorized as “low and high” and Nonlinear Principal Component Analysis was conducted to visually present their relationship with related disease types in two-dimensional space. The upper and lower decision lines were found 3.123 and 2.794 μmol/L, respectively for Malondialdehyde. Those with cirrhosis, chronic kidney disease, acute kidney disease and tomography exposure were included in the upper and lower decision lines. Those with prostate cancer, osteonecrosis, and X-ray exposure were above the upper decision line and are found higher than the overall mean. Those with lung transplantation and MR exposure appear to be below the lower decision line and lower than the overall mean. The present study provides the first comprehensive assessment of the availability of Malondialdehyde, Superoxide dismutase, Catalase and Reduced glutathione levels as markers for some related diseases. This study has shown that Analysis of means can be used as an alternative graphical procedure for multiple group comparisons with an overall mean in the studies regarding as biochemical characteristics and relating diseases. In addition, Nonlinear Principal Component Analysis can be useful aid for decision marker in some biochemical characteristics and related diseases.

Tissue Sodium Accumulation: Pathophysiology and Clinical Implications

Excessive sodium intake has been well established as a risk factor for the development and progression of cardiovascular and renal diseases. Its adverse effects are achieved by renal sodium retention and related volume expansion and by inducing low-grade inflammation and oxidative stress (OS) in the target tissues. This review presents the recent concept of nonosmotic sodium storage in the skin interstitium, the subsequent dissociation of sodium and volume homeostasis, and the cellular response to the increased tissue sodium concentration. Furthermore, data are shown on the sodium barrier and buffering potential of the endothelial glycocalyx that may protect the functional integrity of the endothelium when it is challenged by an increased sodium load. Finally, examples will be given of the involvement of oxygen free radicals (OFR) in sodium-induced tissue damage, and some clinical entities will be mentioned that are causally associated with sodium/volume retention and OS.

Cardio-Oncology: A Myriad of Relationships Between Cardiovascular Disease and Cancer

Cardiovascular disease (CVD) and cancer are the leading causes of death worldwide. With an increasing number of the elderly population, and early cancer screening and treatment, the number of cancers cases are rising, while the mortality rate is decreasing. However, the number of cancer survivors is increasing yearly. With the prolonged life span of cancer patients, the adverse effects of anti-tumor therapy, especially CVD, have gained enormous attention. The incidence of cardiovascular events such as cardiac injury or cardiovascular toxicity is higher than malignant tumors' recurrence rate. Numerous clinical studies have also shifted their focus from the study of a single disease to the interdisciplinary study of oncology and cardiology. Previous studies have confirmed that anti-tumor therapy can cause CVD. Additionally, the treatment of CVD is also related to the tumors incidence. It is well established that the increased incidence of CVD in cancer patients is probably due to an unmodified unhealthy lifestyle among cancer survivors or cardiotoxicity caused by anti-cancer therapy. Nevertheless, some patients with CVD have a relatively increased cancer risk because CVD and malignant tumors are highly overlapping risk factors, including gender, age, hypertension, diabetes, hyperlipidemia, inflammation, and obesity. With advancements in the diagnosis and treatment, many patients simultaneously suffer from CVD and cancer, and most of them have a poor prognosis. Therefore, clinicians should understand the relationship between CVD and tumors, effectively identify the primary and secondary prevention for these diseases, and follow proper treatment methods.

Toxicity of the Pesticides Imidacloprid, Difenoconazole and Glyphosate Alone and in Binary and Ternary Mixtures to Winter Honey Bees: Effects on Survival and Antioxidative Defenses

To explain losses of bees that could occur after the winter season, we studied the effects of the insecticide imidacloprid, the herbicide glyphosate and the fungicide difenoconazole, alone and in binary and ternary mixtures, on winter honey bees orally exposed to food containing these pesticides at concentrations of 0, 0.01, 0.1, 1 and 10 µg/L. Attention was focused on bee survival, food consumption and oxidative stress. The effects on oxidative stress were assessed by determining the activity of enzymes involved in antioxidant defenses (superoxide dismutase, catalase, glutathione-S-transferase, glutathione reductase, glutathione peroxidase and glucose-6-phosphate dehydrogenase) in the head, abdomen and midgut; oxidative damage reflected by both lipid peroxidation and protein carbonylation was also evaluated. In general, no significant effect on food consumption was observed. Pesticide mixtures were more toxic than individual substances, and the highest mortalities were induced at intermediate doses of 0.1 and 1 µg/L. The toxicity was not always linked to the exposure level and the number of substances in the mixtures. Mixtures did not systematically induce synergistic effects, as antagonism, subadditivity and additivity were also observed. The tested pesticides, alone and in mixtures, triggered important, systemic oxidative stress that could largely explain pesticide toxicity to honey bees.

Inflammation and Cardiovascular Disease Associated With Hemodialysis for End-Stage Renal Disease

Chronic kidney disease (CKD) and cardiac insufficiency often co-exist, particularly in uremic patients on hemodialysis (HD). The occurrence of abnormal renal function in patients with cardiac insufficiency is often indicative of a poor prognosis. It has long been established that in patients with cardiac insufficiency, poorer renal function tends to indicate poorer cardiac mechanics, including left atrial reserve strain, left ventricular longitudinal strain, and right ventricular free wall strain (Unger et al., Eur J Heart Fail, 2016, 18(1), 103–12). Similarly, patients with chronic kidney disease, particularly uremic patients on HD, often have cardiovascular complications in addition to abnormal endothelial function with volume overload, persistent inflammatory states, calcium overload, and imbalances in redox responses. Cardiac insufficiency due to uremia is therefore mainly due to multifaceted non-specific pathological changes rather than pure renal insufficiency. Several studies have shown that the risk of adverse cardiovascular events is greatly increased and persistent in all patients treated with HD, especially in those who have just started HD treatment. Inflammation, as an important intersection between CKD and cardiovascular disease, is involved in the development of cardiovascular complications in patients with CKD and is indicative of prognosis (Chan et al., Eur Heart J, 2021, 42(13), 1244–1253). Therefore, only by understanding the mechanisms underlying the sequential development of inflammation in CKD patients and breaking the vicious circle between inflammation-mediated renal and cardiac insufficiency is it possible to improve the prognosis of patients with end-stage renal disease (ESRD). This review highlights the mechanisms of inflammation and the oxidative stress that co-exists with inflammation in uremic patients on dialysis, as well as the mechanisms of cardiovascular complications in the inflammatory state, and provides clinical recommendations for the anti-inflammatory treatment of cardiovascular complications in such patients.

The Effects of Blueberry Phytochemicals on Cell Models of Inflammation and Oxidative Stress

Blueberries have been extensively studied for the health benefits associated with their high phenolic content. The positive impact of blueberry consumption on human health is associated in part with modulation of proinflammatory molecular pathways and oxidative stress. Here, we review in vitro studies examining the anti-inflammatory and antioxidant effects of blueberry phytochemicals, discuss the results in terms of relevance to disease and health, and consider how different blueberry components modulate cellular mechanisms. The dampening effects of blueberry-derived molecules on inflammation and oxidative stress in cell models have been demonstrated through downregulation of the NF-κB pathway and reduction of reactive oxygen species (ROS) and lipid peroxidation. The modulatory effects of blueberry phytochemicals on the mitogen-activated protein kinase (MAPK) pathway and antioxidant system are not as well described, with inconsistent observations reported on immune cells and between models of endothelial, dermal, and ocular inflammation. Although anthocyanins are often reported as being the main bioactive compound in blueberries, no individual phytochemical has emerged as the primary compound when different fractions are compared; rather, an effect of whole blueberry extracts or synergy between different phenolic and nonphenolic extracts seems apparent. The major molecular mechanisms of blueberry phytochemicals are increasingly defined in cell models, but their relevance in more complex human systems needs further investigation using well-controlled clinical trials, in which systemic exposures to blueberry-associated molecules are measured concurrently with physiologic indices of inflammation and oxidative stress.

Collecting Duct-Specific CR6-Interacting Factor-1-Deletion Aggravates Renal Inflammation and Fibrosis Induced by Unilateral Ureteral Obstruction

Although inflammation and fibrosis, which are key mechanisms of chronic kidney disease, are associated with mitochondrial damage, little is known about the effects of mitochondrial damage on the collecting duct in renal inflammation and fibrosis. To generate collecting duct-specific mitochondrial injury mouse models, CR6-interacting factor-1 (CRIF1) flox/flox mice were bred with Hoxb7-Cre mice. We evaluated the phenotype of these mice. To evaluate the effects on unilateral ureteral obstruction (UUO)-induced renal injury, we divided the mice into the following four groups: a CRIF1flox/flox (wild-type (WT)) group, a CRIF1flox/flox-Hob7 Cre (CRIF1-KO) group, a WT-UUO group, and a CRIF1-KO UUO group. We evaluated the blood and urine chemistries, inflammatory and fibrosis markers, light microscopy, and electron microscopy of the kidneys. The inhibition of Crif1 mRNA in mIMCD cells reduced oxygen consumption and membrane potential. No significant differences in blood and urine chemistries were observed between WT and CRIF1-KO mice. In UUO mice, monocyte chemoattractant protein-1 and osteopontin expression, number of F4/80 positive cells, transforming growth factor-β and α-smooth muscle actin staining, and Masson's trichrome staining were significantly higher in the kidneys of CRIF1-KO mice compared with the kidneys of WT mice. In sham mice, urinary 8-hydroxydeoxyguanosine (8-OHDG) was higher in CRIF1-KO mice than in WT mice. Moreover, CRIF1-KO sham mice had increased 8-OHDG-positive cell recruitment compared with WT-sham mice. CRIF1-KO-UUO kidneys had increased recruitment of 8-OHDG-positive cells compared with WT-UUO kidneys. In conclusion, collecting duct-specific mitochondrial injury increased oxidative stress. Oxidative stress associated with mitochondrial damage may aggravate UUO-induced renal injury.

Tear And Serum Superoxide Dismutase And Catalase Activities In Hypertensive Retinopathy

The objective was to determine the changes in SOD and catalase activity, markers of oxidative stress/antioxidant balance in serum and tear of patients with hypertensive retinopathy and to identify whether there was a correlation between their levels and HR degree of hypertensive retinopathy (HR). Material and Methods — 90 hypertensive patients were divided in three groups, according to the Keith-Wagener classification: GI-36, GII-35 and GIII-19. SOD was assessed using the Dubinina and Matyushin method and catalase according to Koroliuk, both in modification of Gudumac V. The results were presented by median and interquartile range. The groups were compared using Kruskal-Wallis and Mann-Whitney nonparametric tests, and the Spearman correlation coefficient was calculated (SPSS 23.0). Results — Showed a statistically significant difference of SOD in serum (p=0.035) and tear (p=0.027) between groups. SOD decreased from GI until GIII in serum (-8%, p=0.032) and tear (-16%, p=0.031). In addition, it showed a weak significant negative correlation with the HR degree both in serum (r=-0.246, p=0.019) and tear (r=-0.284, p=0.007), while the correlation attested between serum and tear SOD levels was significant moderate and positive (r=0.336, p=0.001). It was noted a significant catalase elevation in the tear (p=0.033). In serum it was not correlated with HR degree, while in tear showed a significant weak strength, positive correlation (r=0.261, p=0.013). No correlations were found between serum and tear catalase levels. Conclusion — A progressive significant decrease in SOD levels and a tendency to increase of catalase activity was identified as HR advanced both in serum and in tear. The enhancement in the severity of HR was correlated with decreased SOD activity in tear and serum and increased catalase level in tear.

Framing Cause-Effect Relationship of Acute Coronary Syndrome in Patients with Chronic Kidney Disease

The main causes of death in patients with chronic kidney disease (CKD) are of cardiovascular nature. The interaction between traditional cardiovascular risk factors (CVRF) and non-traditional risk factors (RF) triggers various complex pathophysiological mechanisms that will lead to accelerated atherosclerosis in the context of decreased renal function. In terms of mortality, CKD should be considered equivalent to ischemic coronary artery disease (CAD) and properly monitored. Vascular calcification, endothelial dysfunction, oxidative stress, anemia, and inflammatory syndrome represents the main uremic RF triggered by accumulation of the uremic toxins in CKD subjects. Proteinuria that appears due to kidney function decline may initiate an inflammatory status and alteration of the coagulation—fibrinolysis systems, favorizing acute coronary syndromes (ACS) occurrence. All these factors represent potential targets for future therapy that may improve CKD patient’s survival and prevention of CV events. Once installed, the CAD in CKD population is associated with negative outcome and increased mortality rate, that is the reason why discovering the complex pathophysiological connections between the two conditions and a proper control of the uremic RF are crucial and may represent the solutions for influencing the prognostic. Exclusion of CKD subjects from the important trials dealing with ACS and improper use of the therapeutical options because of the declined kidney functioned are issues that need to be surpassed. New ongoing trials with CKD subjects and platelets reactivity studies offers new perspectives for a better clinical approach and the expected results will clarify many aspects.

Blood urea nitrogen, blood urea nitrogen to creatinine ratio and incident stroke: The Dongfeng-Tongji cohort

BACKGROUND AND AIMS

It remains unclear whether extreme levels of blood urea nitrogen (BUN) and BUN to creatinine ratio (BUN/Cr) can increase future risk of stroke. We conducted this study to investigate the associations of BUN and BUN/Cr with incident stroke and its subtypes.

METHODS

A total of 26,835 and 26,379 participants with a mean follow-up of 7.9 years were included to investigate the associations of BUN and BUN/Cr with incident stroke, respectively. Cox proportional hazard models were used to evaluate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident stroke and its subtypes.

RESULTS

Compared with participants in the third quintile of BUN, the adjusted HRs (95% CIs) for participants in the lowest quintile were 1.21 (1.04-1.40), 1.41 (1.18-1.68) and 1.36 (0.97-1.91) for total, ischemic and hemorrhagic stroke, respectively; while for those in the highest quintile, the corresponding HRs (95% CIs) were 1.16 (1.01-1.32), 1.30 (1.11-1.53), and 1.24 (0.90-1.71). The associations remained robust when restricting the analyses to participants within clinically normal range of BUN. For BUN/Cr, compared with participants in the third quintile, participants in the lowest quintile had significant higher risks of stroke (HRs [95% CIs] were 1.19 [1.04-1.37], 1.26 [1.07-1.48], and 1.22 [0.90-1.67] for total, ischemic and hemorrhagic stroke).

CONCLUSIONS

Both high and low levels of BUN were associated with higher risks of total and ischemic stroke. Low level of BUN/Cr was associated with excess risks of total and ischemic stroke.

Cardiorenal Syndrome: An Important Subject in Nephrocardiology

Coexisting dysfunction of heart and kidney, the cardiorenal syndrome, is a common condition and is associated with worsening of outcomes and complexities of diagnostic, preventive, and therapeutic approaches. The knowledge of the physiology of heart and kidney and their interaction with each other and with other organ systems has progressed significantly in recent years, resulting in a better understanding of the pathogenesis of cardiorenal syndrome. A robust knowledge of the pathophysiology and of the latest practical advancements about cardiorenal syndrome is necessary for cardiologists, nephrologists, and other practitioners who provide medical care to the patients with heart and kidney diseases.

Dynamic regulation of anti-oxidation following donation repairing after circulatory determined death renal transplantation with prolonged non-heart-beating time

Donation after circulatory-determined death (DCD) is an important part of renal transplantation. Therefore, DCD renal transplantation animal model should be established to study the mechanism of organ injury. Here, we established a stable DCD rat renal transplantation model and investigated the dynamic regulation of graft self-repairing and antioxidant capacities with different non-heart-beating times (NHBTs). Male Sprague-Dawley rats were randomly divided into four groups with the NHBT of the donors from 0 to 15, 30, and 45 minutes. Recipients in long NHBT groups had a significantly lower survival rate and poorer graft function than those in short NHBT groups. Grafts from the 15-minute and 30-minute NHBT groups showed light and severe injury respectively at an early stage after transplantation and recovered within 7 days after transplantation, whereas the self-repairing of the grafts in the 45-minute NHBT group was delayed. The expressions of proliferating cell nuclear antigen (PCNA) and von Willebrand factor (vWF) were dependent on NHBT. The expression of antioxidant proteins paralleled graft recovery. In conclusion, the recipients can up-regulate antioxidant capacity to enhance graft self-repairing in DCD renal transplantation. Prolonged NHBT can delay the self-repairing and antioxidation of grafts.

Implications of oxidative stress in chronic kidney disease: a review on current concepts and therapies

Moderate levels of endogenous reactive oxygen species (ROS) are important for various cellular activities, but high levels lead to toxicity and are associated with various diseases. Levels of ROS are maintained as a balance between oxidants and antioxidants. Accumulating data suggest that oxidative stress is a major factor in deterioration of renal function. In this review, we highlight the possible mechanism by which oxidative stress can lead to chronic kidney disease (CKD). This review also describes therapies that counter the effect of oxidative stress in CKD patients. Numerous factors such as upregulation of genes involved in oxidative phosphorylation and ROS generation, chronic inflammation, vitamin D deficiency, and a compromised antioxidant defense mechanism system cause progressive detrimental effects on renal function that eventually lead to loss of kidney function. Patients with renal dysfunction are highly susceptible to oxidative stress, as risk factors such as diabetes, renal hypertension, dietary restrictions, hemodialysis, and old age predispose them to increased levels of ROS. Biomolecular adducts (DNA, proteins, and lipids) formed due to reaction with ROS can be used to determine oxidative stress levels. Based on the strong correlation between oxidative stress and CKD, reversal of oxidative stress is being explored as a major therapeutic option. Xanthine oxidase inhibitors, dietary antioxidants, and other agents that scavenge free radicals are gaining interest as treatment modalities in CKD patients.

Vascular pathologies in chronic kidney disease: pathophysiological mechanisms and novel therapeutic approaches

Cardiovascular disease (CVD) is a major cause of death in patients with chronic kidney disease (CKD). Both conditions are rising in incidence as well as prevalence, creating poor outcomes for patients and high healthcare costs. Recent data suggests CKD to be an independent risk factor for CVD. Accumulation of uremic toxins, chronic inflammation, and oxidative stress have been identified to act as CKD-specific alterations that increase cardiovascular risk. The association between CKD and cardiovascular mortality is markedly influenced through vascular alterations, in particular atherosclerosis and vascular calcification (VC). While numerous risk factors promote atherosclerosis by inducing endothelial dysfunction and its progress to vascular structural damage, CKD affects the medial layer of blood vessels primarily through VC. Ongoing research has identified VC to be a multifactorial, cell-mediated process in which numerous abnormalities like mineral dysregulation and especially hyperphosphatemia induce a phenotype switch of vascular smooth muscle cells to osteoblast-like cells. A combination of pro-calcifying stimuli and an impairment of inhibiting mechanisms like fetuin A and vitamin K-dependent proteins like matrix Gla protein and Gla-rich protein leads to mineralization of the extracellular matrix. In view of recent studies, intercellular communication pathways via extracellular vesicles and microRNAs represent key mechanisms in VC and thereby a promising field to a deeper understanding of the involved pathomechanisms. In this review, we provide an overview about pathophysiological mechanisms connecting CKD and CVD. Special emphasis is laid on vascular alterations and more recently discovered molecular pathways which present possible new therapeutic targets.

Catalytic Antioxidants in the Kidney

Reactive oxygen species and reactive nitrogen species are highly implicated in kidney injuries that include acute kidney injury, chronic kidney disease, hypertensive nephropathy, and diabetic nephropathy. Therefore, antioxidant agents are promising therapeutic strategies for kidney diseases. Catalytic antioxidants are defined as small molecular mimics of antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, and some of them function as potent detoxifiers of lipid peroxides and peroxynitrite. Several catalytic antioxidants have been demonstrated to be effective in a variety of in vitro and in vivo disease models that are associated with oxidative stress, including kidney diseases. This review summarizes the evidence for the role of antioxidant enzymes in kidney diseases, the classifications of catalytic antioxidants, and their current applications to kidney diseases.

Linking chronic kidney disease and Parkinson's disease: a literature review

Chronic kidney disease (CKD) has been typically implicated in cardiovascular risk, considering the function the kidney has related to blood pressure, vitamin D, red blood cell metabolism, and electrolyte and acid-base regulation. However, neurological consequences are also attributed to this disease. Among these, recent large epidemiological studies have demonstrated an increased risk for Parkinson's disease (PD) in patients with CKD. Multiple studies have evaluated individually the association of blood pressure, vitamin D, and red blood cell dysmetabolism with PD, however, no study has reviewed the potential mechanisms related to these components in context of CKD and PD. In this review, we explored the association of CKD and PD and linked the components of the former to propose potential pathways explaining a future increased risk for PD, where renin-angiotensin system, oxidative stress, and inflammation have a main role. Potential preventive and therapeutic interventions based on these associations are also explored. More preclinical studies are needed to confirm the potential link of CKD conditions and future PD risk, whereas more interventional studies targeting this association are warranted to confirm their potential benefit in PD.

Effect of uremic serum on Th17/Treg cell balance and endoplasmic reticulum stress in rats

BACKGROUND/AIMS

The imbalance of T helper 17 (Th17) and regulatory T (Treg) cells exists in the occurrence and development of various diseases. Endoplasmic reticulum stress (ERS) is an important self-protective cellular response to harmful stimuli, such as uremic environment. The objective of this study was to investigate the Th17/Treg cell balance and ERS in a uremic environment and analyze the relationship between them.

METHODS

(1) The rat spleen lymphocytes were extracted and treated with thapsigargin (inducer of ERS) and sodium citrate. The proportion of Th17 and Treg cells were then detected. (2) The uremic serum-cultured lymphocytes were used and divided into three groups: non-uremic serum group, uremic serum group, and uremic serum + sodium citrate group. Afterward, the proportion of Th17/Treg cells and the expression of ERS-related proteins (GRP78 and CHOP) were detected.

RESULTS

Thapsigargin had no significant effect on the proportion of Th17 cells within a limited concentration range, but it could reduce the proportion of Treg cells, sodium citrate had a negative influence on the deviation of Th17/Treg cells treated with thapsigargin. Uremic serum treatment reduced the proportion of Treg cells, resulting in an increase of the Th17/Treg ratio. However, sodium citrate had no influence on the deviation of Th17/Treg cells treated by uremic serum. Sodium citrate reduced the elevation of ERS-related proteins induced by uremic serum.

CONCLUSIONS

Uremic serum can lead to the imbalance of Th17/Treg cells as well as ERS, suggesting that ERS is one of the mechanisms of the imbalance of Th17/Treg cells induced by uremic serum. Sodium citrate can inhibit ERS induced by uremic serum.

Chronic Kidney Disease as Oxidative Stress- and Inflammatory-Mediated Cardiovascular Disease

Generating reactive oxygen species (ROS) is necessary for both physiology and pathology. An imbalance between endogenous oxidants and antioxidants causes oxidative stress, contributing to vascular dysfunction. The ROS-induced activation of transcription factors and proinflammatory genes increases inflammation. This phenomenon is of crucial importance in patients with chronic kidney disease (CKD), because atherosclerosis is one of the critical factors of their cardiovascular disease (CVD) and increased mortality. The effect of ROS disrupts the excretory function of each section of the nephron. It prevents the maintenance of intra-systemic homeostasis and leads to the accumulation of metabolic products. Renal regulatory mechanisms, such as tubular glomerular feedback, myogenic reflex in the supplying arteriole, and the renin–angiotensin–aldosterone system, are also affected. It makes it impossible for the kidney to compensate for water–electrolyte and acid–base disturbances, which progress further in the mechanism of positive feedback, leading to a further intensification of oxidative stress. As a result, the progression of CKD is observed, with a spectrum of complications such as malnutrition, calcium phosphate abnormalities, atherosclerosis, and anemia. This review aimed to show the role of oxidative stress and inflammation in renal impairment, with a particular emphasis on its influence on the most common disturbances that accompany CKD.

Decreased biventricular myocardial deformation in fetuses with lower urinary tract obstruction

BACKGROUND

To observe myocardial deformations in fetuses with isolated lower urinary tract obstruction (LUTO) and identify the correlation between myocardial deformation and the severity of obstruction.

METHODS

The strain (S), strain rate in systole (SRs) and strain rate in diastole (SRd) of the left and right ventricles at the first examination were prospectively analyzed and compared between fetuses with isolated LUTO and gestational age (GA)-matched normal control fetuses. Multiple regression analyses were used to assess the obstructive factors for impaired strain and strain rate, and the independent variables included bladder volume, sum of the bilateral pelvic diameters, sum of the bilateral ureteral diameters, mean bilateral renal artery pulsatility index, and amniotic fluid index.

RESULTS

Thirty-six fetuses with isolated LUTO and 36 normal controls were enrolled. Overall, decreased S, SRs and SRd of both ventricles were noted in fetuses with LUTO (p < 0.001). Moreover, S and SR were significantly negatively related to distended bladder volume (p < 0.001).

CONCLUSIONS

Fetuses with LUTO demonstrated decreased left and right myocardial deformation, and this impaired cardiac dysfunction was correlated with the urinary bladder volume. Evaluating the myocardial deformation in fetal LUTO could provide information to aid in parental counselling and intervention monitoring.

The effect of nutraceuticals on multiple signaling pathways in cardiac fibrosis injury and repair

Cardiac fibrosis is one of the most common pathological conditions caused by different heart diseases, including myocardial infarction and diabetic cardiomyopathy. Cardiovascular disease is one of the major causes of mortality worldwide. Cardiac fibrosis is caused by different processes, including inflammatory reactions and oxidative stress. The process of fibrosis begins by changing the balance between production and destruction of extracellular matrix components and stimulating the proliferation and differentiation of cardiac fibroblasts. Many studies have focused on finding drugs with less adverse effects for the treatment of cardiovascular disease. Some studies show that nutraceuticals are effective in preventing and treating diseases, including cardiovascular disease, and that they can reduce the risk. However, big clinical studies to prove the therapeutic properties of all these substances and their adverse effects are lacking so far. Therefore, in this review, we tried to summarize the knowledge on pathways and mechanisms of several nutraceuticals which have shown their usefulness in the prevention of cardiac fibrosis.

Influence of Spray-Drying and Room Temperature Storage on the Anti- and Prooxidant Properties of Fermented Juçara Pulp

Many fruits and vegetables contain compounds with antioxidant properties, but the processing and storage conditions of the food industry may damage these beneficial compounds and produce free radicals that are associated with oxidative stress. This study aims to evaluate in vitro the antioxidant capacity and prooxidant effects of juçara pulp fermented with Lactobacillus reuteri or Lactobacillus plantarum before and after spray-drying with maltodextrin, gum arabic or gelatin and stored at 25 °C for 90 days. The antioxidant capacity was assessed by measuring the ability to scavenge reactive oxygen species (ROS) in the neutrophil respiratory burst and free radical 2,2-diphenyl-1-picryl-hydrazyl (DPPH), and by determining the total phenolic content. The prooxidant effects were analyzed as free radical formation measured by electronic paramagnetic resonance (EPR). Fermentation by both bacteria increased the antioxidant activity, while the spray-drying process decreased the content of phenolic compounds (65-85%) and the DPPH scavenging ability, depending on the carrier usage. All of the samples inhibited ROS in the neutrophil burst, and the juçara pulp fermented by L. reuteri and dried with gum arabic exhibited the best performance. Spray-drying did not influence the intensity or type of free radicals detected by EPR. However, storage at room temperature decreased the antioxidant capacity and increased free radical formation.

Chronic Inflammation in Peritoneal Dialysis: The Search for the Holy Grail?

Mortality and morbidity in chronic kidney disease (CKD) patients are unacceptably high. The annual mortality rate due to cardiovascular disease (CVD) is approximately 9%, which, for the middle-aged person, is at least 10- to 20-fold higher than for the general population. Classic risk factors for CVD are highly prevalent in CKD patients, but they cannot fully account for the excessive rate of CVD in this population. Instead, it has become increasingly clear that nontraditional risk factors, such as systemic inflammation, may play a key role in the development of atherosclerosis. It is well established that inflammatory markers are very powerful predictors of high CVD morbidity and mortality not only in the general population, but particularly in CKD patients. Signs of a sustained low-grade inflammation, such as increased levels of C-reactive protein (CRP), are present in the majority of stage 5 CKD patients, even in patients in clinically stable condition, and they are also commonly observed after the initiation of dialysis therapy. Dialysis therapy — hemodialysis as well as peritoneal dialysis (PD) — may itself contribute to systemic inflammation. Local intraperitoneal inflammation can also occur in patients treated with PD. These local effects may result in a low-grade inflammation, caused by the bioincompatibility of conventional glucose-based dialysis fluids, to intense inflammation associated with peritonitis. Given these circumstances, it is reasonable to hypothesize that strategies aiming to reduce inflammation are potentially important and novel, and could serve to reduce CVD, thereby lowering morbidity and mortality in patients with CKD. In this review we provide information supporting the hypothesis that systemic inflammation is tightly linked to the most common complications of CKD patients, in particular those on PD, and that local inflammation in PD may contribute to various related complications. The aims of this review are to discuss the reasons that make inflammation an attractive target for intervention in CKD, the particular aspects of the inflammation–CVD axis during PD treatment that are likely involved, and possible means for the detection and management of chronic inflammation in PD patients.

Oxidative Stress in Hemodialysis Pediatric Patients

BACKGROUND:

Oxidative stress may play a role in complications of hemodialysis patients as atherosclerosis, thrombosis, and inflammation.

AIM:

The aim of the study was to evaluate the oxidative stress in hemodialysis pediatric patients through measurement of oxidative stress enzymes as paraoxanase activity (PON), arylesterase activity (ASA), superoxide dismutase (SOD) and also non-enzymatic antioxidant vitamins as vitamins A, C and E levels.

METHODS:

The study included 50 hemodialysis pediatric patients with mean age 11.4 ± 5.4 years and 30 normal children of matched sex and age as a control group. Assessment of oxidative stresses was done using ELIZA technique.

RESULTS:

SOD, ASA, and vitamin C were significantly lower among hemodialysis patients in comparison to control group (p = 0.004, 0.004, > 0.001 respectively).

CONCLUSION:

The study concluded that oxidative stress was common finding in hemodialysis pediatric patients which may play a role in complications encountered among these patients.

Reducing Pancreatic Fibrosis Using Antioxidant Therapy Targeting Nrf2 Antioxidant Pathway: A Possible Treatment for Chronic Pancreatitis

Chronic pancreatitis is the progressive inflammation of the pancreas resulting in the irreversible damage of pancreatic structure and function by means of fibrosis. Chronic pancreatitis is most commonly caused by alcohol consumption, although the direct molecular etiology is unknown. Recent studies suggest oxidative stress as a catalyst for pancreatic stellate cell activation leading to the deposition of collagenous extracellular matrix causing pancreatic fibrosis. We review the effect of oxidative stress on pancreatic fibrogenesis and indicate the molecular pathways involved in preventing oxidant-related cell damage. Likewise, we summarize existing antioxidative therapies for chronic pancreatitis and discuss a novel nuclear factor erythroid 2-related factor 2 activator, dimethyl fumarate, and its potential to reduce fibrogenesis by downregulating pancreatic stellate cell activation.

N-acetyl-l-cysteine exacerbates kidney dysfunction caused by a chronic high-sodium diet in renal ischemia and reperfusion rats

AIMS

To investigate the effect of long-term N-acetyl-l-cysteine (NAC) treatment in Wistar rats subjected to renal ischemia and reperfusion (IR) and a chronic high‑sodium diet (HSD).

MAIN METHODS

Adult male Wistar rats received an HSD (8.0% NaCl) or a normal‑sodium diet (NSD; 1.3% NaCl) and NAC (600 mg/L) or normal drinking water starting at 8 weeks of age. At 11 weeks of age, the rats from both diet and NAC or water treatment groups underwent renal IR or Sham surgery and were followed for 10 weeks. The study consisted of six animal groups: NSD + Sham + water; NSD + IR + water; NSD + IR + NAC; HSD + Sham + water; HSD + IR + water; and HSD + IR + NAC.

KEY FINDINGS

Tail blood pressure (tBP) increased with IR and NAC treatment in the NSD group but not in the HSD group. The serum creatinine level was higher after NAC treatment in both diet groups, and creatinine clearance was decreased in only the HSD + IR + NAC group. Albuminuria increased in the HSD + IR + water group and decreased in the HSD + IR + NAC group. Kidney mass was increased in the HSD + IR group and decreased with NAC treatment. Renal fibrosis was prevented with NAC treatment and cardiac fibrosis was decreased with NAC treatment in the HSD + IR group.

SIGNIFICANCE

NAC treatment promoted structural improvements, such as decreased albuminuria and fibrosis, in the kidney and heart. However, NAC could not recover kidney function or blood pressure from the effects of IR associated with an HSD. Therefore, in general, long-term NAC treatment is not effective and is deleterious to recovery of function after kidney injury.

Measuring and regulating oxygen levels in microphysiological systems: design, material, and sensor considerations

As microfabrication techniques and tissue engineering methods improve, microphysiological systems (MPS) are being engineered that recapitulate complex physiological and pathophysiological states to supplement and challenge traditional animal models. Although MPS provide unique microenvironments that transcend common 2D cell culture, without proper regulation of oxygen content, MPS often fail to provide the biomimetic environment necessary to activate and investigate fundamental pathways of cellular metabolism and sub-cellular level. Oxygen exists in the human body in various concentrations and partial pressures; moreover, it fluctuates dramatically depending on fasting, exercise, and sleep patterns. Regulating oxygen content inside MPS necessitates a sensitive biological sensor to quantify oxygen content in real-time. Measuring oxygen in a microdevice is a non-trivial requirement for studies focused on understanding how oxygen impacts cellular processes, including angiogenesis and tumorigenesis. Quantifying oxygen inside a microdevice can be achieved via an array of technologies, with each method having benefits and limitations in terms of sensitivity, limits of detection, and invasiveness that must be considered and optimized. This article will review oxygen physiology in organ systems and offer comparisons of organ-specific MPS that do and do not consider oxygen microenvironments. Materials used in microphysiological models will also be analyzed in terms of their ability to control oxygen. Finally, oxygen sensor technologies are critically compared and evaluated for use in MPS.

Poly(ADP-ribose) polymerase 1 accelerates vascular calcification by upregulating Runx2

Vascular calcification is highly prevalent in end-stage renal diseases and is predictive of cardiovascular events and mortality. Poly(ADP-ribose) polymerase 1 (PARP1) inhibition or deletion is vasoprotective in several disease models. Here we show that PARP activity is increased in radial artery samples from patients with chronic renal failure, in arteries from uraemic rats, and in calcified vascular smooth muscle cells (VSMCs) in vitro. PARP1 deficiency blocks, whereas PARP1 overexpression exacerbates, the transdifferentiation of VSMCs from a contractile to an osteogenic phenotype, the expression of mineralization-regulating proteins, and calcium deposition. PARP1 promotes Runx2 expression, and Runx2 deficiency offsets the pro-calcifying effects of PARP1. Activated PARP1 suppresses miRNA-204 expression via the IL-6/STAT3 pathway and thus relieves the repression of its target, Runx2, resulting in increased Runx2 protein. Together, these results suggest that PARP1 counteracts vascular calcification and that therapeutic agents that influence PARP1 activity may be of benefit to treat vascular calcification.

Vascular calcification is a hallmark of end stage renal disease. Here, Cheng et al. show that poly(ADP-ribose) polymerase (PARP) activity is increased in calcified arteries in patients and uremic rats, and that PARP1 promotes vascular calcification by suppressing miR-204 expression via IL-6/STAT3 signaling, thus relieving repression of the osteogenic regulator Runx2.

Class I histone deacetylase inhibitor MS-275 attenuates vasoconstriction and inflammation in angiotensin II-induced hypertension

Objective

Non-selective histone deacetylase (HDAC) inhibitors are known to improve hypertension. Here, we investigated the therapeutic effect and regulatory mechanism of the class I HDAC selective inhibitors, MS-275 and RGFP966, in angiotensin (Ang) II-induced hypertensive mice.

Methods and results

MS-275 inhibited the activity of HDAC1, HDAC2, and HDAC3, while RGFP966 weakly inhibited that of HDAC3 in a cell-free system. MS-275 and RGFP966 treatment reduced systolic blood pressure and thickness of the aorta wall in Ang II-induced hypertensive mice. MS-275 treatment reduced aorta collagen deposition, as determined by Masson’s trichrome staining. MS-275 decreased the components of the renin angiotensin system and increased vascular relaxation of rat aortic rings via the nitric oxide (NO) pathway. NO levels reduced by Ang II were restored by MS-275 treatment in vascular smooth muscle cells (VSMCs). However, MS-275 dose (3 mg·kg^-1·day^-1) was not enough to induce NO production in vivo. In addition, MS-275 did not prevent endothelial nitric oxide synthase (eNOS) uncoupling in the aorta of Ang II-induced mice. Treatment with MS-275 failed to inhibit Ang II-induced expression of NADPH oxidase (Nox)1, Nox2, and p47phox. MS-275 treatment reduced proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and monocyte chemoattractant protein (MCP)-1, as well as adhesion molecules. Histological analysis showed that Ang II-induced macrophage infiltration was reduced by MS-275 and RGFP966 administration.

Conclusions

Our results indicate that class I HDAC selective inhibitors may be good therapeutic agents for the treatment of hypertension through the regulation of vascular remodeling and vasoconstriction, as well as inflammation.

(Pro)renin Receptor Blockade Ameliorates Heart Failure Caused by Chronic Kidney Disease

BACKGROUND

The (pro)renin receptor [(P)RR)] is involved in the activation of local renin-angiotensin system and subsequent development of cardiovascular disease. We investigated the therapeutic effect of a (P)RR blocker, handle-region peptide (HRP), on chronic kidney disease (CKD)-associated heart failure.

METHODS AND RESULTS

CKD was induced in C57BL/6J mice by means of five-sixths nephrectomy. Eight weeks later, cardiac dysfunction and cardiac dilatation with hypertension developed. Mice were then assigned to 1 of the 3 following groups: vehicle, low-dose (0.01 mg·kg^-1·d^-1) HRP, or high-dose (0.3 mg·kg^-1·d^-1) HRP for 4 weeks. High-dose HRP treatment reversed left ventricular dilation and significantly improved cardiac dysfunction with ameliorated hypertension compared with the vehicle. The hearts with high-dose HRP treatment showed significant attenuation of cardiac fibrosis, cardiomyocyte hypertrophy, macrophage infiltration, and oxidative DNA damage. This treatment decreased the myocardial expressions of angiotensin (Ang) II, Ang II type 1 receptor, transforming growth factor β1, extracellular matrix-related proteins, and lipid peroxidation. Autophagy was activated in the cardiomyocyte from nephrectomized mice, but HRP treatment had no effect on cardiomyocyte autophagy.

CONCLUSIONS

This study indicates that (P)PR blockade is a beneficial strategy by suppressing cardiac fibrosis and hypertrophy to ameliorate heart failure caused by CKD.

Effects of Pulmonary Hypertension and Right Ventricular Function in Short and Long-Term Kidney Function

BACKGROUND

Pulmonary hypertension is not uncommon in patients with renal disease and vice versa; therefore, it influences treatments and outcomes. There is a large body of literature on pulmonary hypertension in patients with kidney disease, its prognostic implications, economic burden, and management strategies. However, the converse, namely the hemodynamic effects of pulmonary hypertension on kidney function (acute and chronic kidney injury) is less studied and described. There is also increasing interest in the effects of pulmonary hypertension on kidney transplant outcomes. The relationship is a complex phenomenon and multiple body systems and mechanisms are involved in its pathophysiology. Although the definition of pulmonary hypertension has evolved over time with the understanding of multiple interplays between the heart, lungs, kidneys, etc; there is limited evidence to provide a specific treatment strategy when kidneys and lungs are affected at the same time. Nevertheless, available evidence appears to support new therapeutics and highlights the importance of individualized approach. There is sufficient research showing that the morbidity and mortality from PH are driven by the influence of the pulmonary hemodynamic dysfunction on the kidneys.

CONCLUSION

This concise review focuses on the effects of pulmonary hypertension on the kidneys, including, the patho-physiological effects of pulmonary hypertension on acute kidney injury, progression of CKD, effects on kidney transplant outcomes, progression of kidney disease in situations such as post LVAD implantation and novel diagnostic indices. We believe a review of this nature will fill in an important gap in understanding the prognostic implication of pulmonary hypertension on renal disease, and help highlight this important component of the cardio-reno-pulmonary axis.

Paricalcitol attenuates indoxyl sulfate-induced apoptosis through the inhibition of MAPK, Akt, and NF-kB activation in HK-2 cells

BACKGROUND/AIMS

Indoxyl sulfate (IS) is a uremic toxin and an important causative factor in the progression of chronic kidney disease. Recently, paricalcitol (19-nor-1,25-dihydroxyvitamin D2) was shown to exhibit protective effects in kidney injury. Here, we investigated the effects of paricalcitol treatment on IS-induced renal tubular injury.

METHODS

The fluorescent dye 2',7'-dichlorofluorescein diacetate was used to measure intracellular reactive oxygen species (ROS) following IS administration in human renal proximal tubular epithelial (HK-2) cells. The effects of IS on cell viability were determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays and levels of apoptosis-related proteins (Bcl-2-associated protein X [Bax] and B-cell lymphoma 2 [Bcl-2]), nuclear factor-κB (NF- κB) p65, and phosphorylation of mitogen-activated protein kinase (MAPK) and protein kinase B (Akt) were determined by semiquantitative immunoblotting. The promoter activity of NF-κB was measured by luciferase assays and apoptosis was determined by f low cytometry of cells stained with f luorescein isothiocyanate-conjugated Annexin V protein.

RESULTS

IS treatment increased ROS production, decreased cell viability and induced apoptosis in HK-2 cells. IS treatment increased the expression of apoptosis-related protein Bax, decreased Bcl-2 expression, and activated phosphorylation of MAPK, NF-κB p65, and Akt. In contrast, paricalcitol treatment decreased Bax expression, increased Bcl-2 expression, and inhibited phosphorylation of MAPK, NF-κB p65, and Akt in HK-2 cells. NF-κB promoter activity was increased following IS, administration and was counteracted by pretreatment with paricalcitol. Additionally, flow cytometry analysis revealed that IS-induced apoptosis was attenuated by paricalcitol treatment, which resulted in decreased numbers of fluorescein isothiocyanate-conjugated Annexin V positive cells.

CONCLUSION

Treatment with paricalcitol inhibited IS-induced apoptosis by regulating MAPK, NF-κB, and Akt signaling pathway in HK-2 cells.

Effects of hydroxyethyl starch 130/0.4 on the kidney tissue of rats with ureteral obstruction

Objective

This study was conducted since the effects of colloid solutions on the renal system remain controversial and need to be adequately studied in animals. We aimed to evaluate the effects of hydroxyethyl starch (Voluven) on the kidney tissue of rats with late renal failure due to ureteral obstruction.

Materials and methods

Rats were divided into four groups: Group C, control; Group HES, hydroxyethyl starch solution (HES) 130/0.4 (Voluven^®); Group UUO, unilateral ureteral obstruction (UUO); and Group UUO-HES, UUO-HES 130/0.4 (Voluven^®). In the groups with ureteral obstruction, the distal part of the right ureter was accessed and sutured through a lower abdominal incision under ketamine anesthesia. Any signs of late-stage renal failure were evaluated after three weeks. Rats in the HES group and the renal failure-HES group were administered with HES 130/0.4 as a single intravenous dose of 20 mL/kg. After a follow-up of 24 hours, intra-abdominal blood sample was collected, and the rats were sacrificed. Biochemical and histopathological parameters were then evaluated.

Results

Ureteral obstruction significantly increased urea and creatinine levels. In addition, when the UUO-HES and HES groups were compared, the administration of HES increased urea and creatinine levels in the UUO-HES group. Nitric oxide enzyme activity and malondialdehyde levels have significantly increased in the UUO groups. In addition, HES significantly increased nitric oxide activity and malondialdehyde levels in the UUO-HES group, in comparison with the HES group. The activity of caspases 3 and 8 was significantly increased in the UUO groups. In addition, HES significantly increased the activity of caspases 3 and 8 in the UUO-HES group, in comparison with the HES group. Light microscopy revealed significant changes in the UUO groups, especially in the obstructed kidneys.

Conclusion

If indicated, HES should be used with caution in cases of UUO, but not in the cases of bilateral ureteral obstruction. Other aspects of these findings, including the clinical significance and practical applications, merit further experimental and clinical investigation.

Superoxide via Sp3 mechanism increases renal renin activity, renal AT1 receptor function, and blood pressure in rats

We tested a hypothesis that superoxide, by inducing Sp3, increases renal renin activity, renal angiotensin II type 1 receptor (AT1R) function, and blood pressure (BP) in rats. Group 1 rats were treated with vehicle, saline. Group 2 rats were treated with superoxide dismutase (SOD) inhibitor diethylthiocarbamate (DETC). Group 3 rats were treated with DETC and an SOD mimetic, tempol. Group 4 rats were treated with tempol only. All four groups of rats were treated for 2 wk then anesthetized, and BP was recorded. Thereafter, diuresis and natriuresis in response to AT1R blocker candesartan were determined. When compared with vehicle rats, BP increased in DETC rats. The increased BP in DETC rats decreased with tempol. Diuresis and natriuresis in response to candesartan increased in controls, and this further increased in DETC rats and decreased with tempol. A second set of four groups of rats underwent the same treatment as above and were anesthetized, and their kidneys were obtained for biochemical studies. The levels of superoxide but not hydrogen peroxide increased, whereas SOD activities decreased further in the renal cortical tissues of DETC rats than vehicle rats. These effects were attenuated with tempol in DETC rats. Moreover, tissue renin activity and abundance of membranous AT1R proteins increased more in DETC rats than vehicle rats, and decreased with tempol in DETC rats. Furthermore, the levels of lysine-acetylated, but not serine-phosphorylated, Sp3 increased more in the nuclei of DETC rats than vehicle rats. The increased levels of Sp3 lysine acetylation decreased in DETC rats with tempol. Taken together, our results suggest that superoxide activates renal Sp3 via lysine acetylation increasing renin activity, AT1R function, and BP in rats.

Tempol, a superoxide dismutase mimetic agent, reduces cisplatin-induced nephrotoxicity in rats

Cisplatin (CP) is one of the most potent anti-cancer drugs used against different types of cancer. Its use is limited due to its nephrotoxicity. This study is aimed to evaluate the role of a super oxide dismutase (SOD) mimetic agent, tempol, in protection against CP nephrotoxicity in rats. Animals were divided into four groups: Group-1: Normal control group, Group-2: CP group (single dose of CP 6 mg/kg, i.p.), Group-3 and Group-4: Tempol-treated groups (50 mg/kg p.o. and 100 mg/kg p.o. respectively) daily for a week before CP injection and continued for an additional four days after CP injection. Urine and blood samples were collected for the evaluation of kidney function including serum creatinine, BUN, cystatin-c, and creatinine clearance. In addition, western blotting was used to determine urine lipocalin-2 content. Furthermore, kidney tissue was collected for the determination of oxidative stress markers, caspase-3 expression, and histopathological examination. We noticed that both doses of tempol significantly improved kidney function, which was deteriorated by CP injection. Tempol significantly elevated kidney glutathione (GSH) content and SOD activity, and decreased kidney lipid peroxidation and NOx production. Tempol also significantly decreased kidney caspase-3 expression which was elevated by CP toxicity. Thus, we conclude that tempol can protect against CP nephrotoxicity. We noticed that both doses of tempol are effective in ameliorating CP-nephrotoxicity.

Dietary tetrahydrocurcumin reduces renal fibrosis and cardiac hypertrophy in 5/6 nephrectomized rats

Tetrahydrocurcumin (THC) is the principal metabolite of curcumin and has antioxidant properties. In the present investigation, the effect of THC on renal and cardiovascular outcomes was studied in rats with chronic kidney disease (CKD). CKD rats were randomized following 5/6 nephrectomy to a special diet for 9 weeks which contained 1% THC (CKD+THC group). Low-dose polyenylphosphatidylcholine was used as a lipid carrier to increase bioavailability. Endpoints included tail blood pressure, normalized heart weight, plasma and urine biochemical data, and kidney tissue analyses. CKD animals demonstrated increased proteinuria, decreased creatinine clearance, hypertension, and cardiac hypertrophy. The antioxidant proteins CuZn SOD and glutathione peroxidase were decreased in the remnant kidney, while apoptosis (caspase-3) and fibrosis (alpha-SM actin) were increased. Renal fibrosis was confirmed histologically on trichrome staining. These pathologic changes were ameliorated in the CKD+THC group with significant decrease in proteinuria, hypertension, and kidney fibrosis. THC therapy restored levels of CuZn SOD and glutathione peroxidase. Consistent with prior reports, dietary THC did not improve nuclear Nrf2 levels. In summary, dietary THC therapy improved expression of antioxidant proteins in the remnant kidney, decreased renal fibrosis and proteinuria, and ameliorated hypertension in 5/6 nephrectomized rats.

Glycaemic control in type 2 diabetic patients with chronic kidney disease: the impacts on enzymatic antioxidants and soluble RAGE

Background

Chronic kidney disease (CKD) is characterised by long-term kidney damage and renal function decline. Diabetic CKD is the principal subtype of kidney disease in Malaysia and is associated with oxidative stress which plays an important role in development and progression of the disease. Glycaemic control slows down the progression of diabetic complications, including diabetic CKD. However, the implication of glycaemic control on enzymatic antioxidants and soluble RAGE (sRAGE) in CKD patients remains elusive. The aim of this study was to investigate the effect of glycaemic control on the levels or activities of glutathione peroxidase (GPx), superoxide dismutase (SOD) and sRAGE in CKD patients.

Methods

A total of 150 CKD patients and 64 non-CKD patients were enrolled. The type 2 diabetic patients in the recruited study participants were categorised based on their glycaemic control; poor glycaemic control (GC) with haemoglobin A1c (HbA1c) > 7% and good GC with HbA1c ≤ 7%. The levels or activities of GPx, SOD and sRAGE in plasma were measured. These biochemical parameters were analysed using Mann-Whitney U test and two-way analysis of variance (ANOVA).

Results

The activities of GPx and SOD as well as plasma level of sRAGE were not significantly different among the CKD patients with varying glycaemic control status. Irrespective of diabetes status and glycaemic control status, CKD patients also exhibited lower plasma SOD activities compared with non-CKD patients. Among the non-CKD patients, SOD activities were significantly higher in diabetic patients with good GC than diabetic patients with poor GC. Two-way ANOVA revealed that both CKD status and glycaemic control had an interaction effect on SOD activities in diabetic subjects with and without CKD. Follow-up analysis showed that SOD activities were significantly higher in non-CKD patients with good GC. There were no overall significant differences in GPx activities among the study participants. Furthermore, plasma sRAGE levels were higher in diabetic patients with CKD than those without CKD, regardless of glycaemic control status. There were no interaction effects between CKD status and glycaemic control status on GPx and sRAGE. Instead, CKD status showed significant main effects on these parameters, indicating significant differences between diabetic subjects with CKD and diabetic subjects without CKD.

Conclusion

Glycaemic control did not quantitatively alter GPx, SOD and sRAGE in diabetic CKD patients. Despite the advantages of good glycaemic control, a well-controlled diabetes in CKD did not modulate the activities of enzymatic antioxidants and sRAGE levels, therefore may not be the primary mechanism to handle oxidative stress.

Oxidative stress as a possible mechanism of statin-induced myopathy

Statins, inhibitors of hydroxy methyl glutaryl coenzyme-A (HMG-CoA) reductase, are the most widely used drugs for treating hypercholesterolemia. However, statins can cause disabling myopathy as their main adverse effect. Several molecular mechanisms underlie the statin-induced myopathy including the decrease in the levels of essential mevalonate and cholesterol derivatives. This review discusses a further mechanism involving the loss of other anti-oxidant defenses besides ubiquinone (Co-Q) in skeletal muscles which produce a significant amount of reactive oxygen species (ROS). Therefore, to maintain their function, skeletal muscles need a high level of anti-oxidants.

Anti-Hypertensive Effects of Acacia Polyphenol in Spontaneously Hypertensive Rats

We have previously demonstrated that acacia polyphenol (AP) exerts strong anti-obesity, anti-diabetic, and anti-atopic dermatitis effects. In the present study, we investigated the anti-hypertensive effects of AP. Spontaneously hypertensive rats (SHR) with hypertension and control Wistar Kyoto rats (WKY) were used. WKY and SHR were fed AP-containing food or AP-free food (control group) ad libitum for 4 weeks, and their blood pressures were measured. After AP administration, both systolic and diastolic blood pressures were significantly lower in the SHR group than in the control group. There were no differences in the systolic or diastolic blood pressure of WKY between the AP group and the control group. Angiotensin-converting enzyme (ACE) activity, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression, and superoxide dismutase (SOD) activity in SHR kidneys were not altered by AP administration. Blood SOD activity in SHR was significantly higher in the AP group than in the control group. AP exerts anti-hypertensive effects on hypertension but has almost no effect on normal blood pressure. The anti-hypertensive effects of AP may be related to the anti-oxidative effects of increased blood SOD activity.

Influence of different concentrations of uric acid on oxidative stress in steatosis hepatocytes

The development of nonalcoholic fatty liver disease (NAFLD) is caused by the steatosis of hepatocytes, which induces oxidative stress (OS). Thus, OS has an important role in the development of NAFLD. In the present study, the L-02 hepatocyte cell line was used to develop a steatosis cell model. The best model was determined using an MTT assay and the triglyceride levels. Model cells were treated with high concentrations of uric acid (UA; 0, 5, 10, 20 and 30 mg/dl) for 24, 48, 72 and 96 h. Indicators of oxidation were then measured, which included total superoxide dismutase (SOD), malonaldehyde (MDA) and reduced glutathione (GSH), and the transcriptional and translational levels of SOD1 and γ-glutamate-cysteine ligase (γ-GCLC) were also determined. In addition, the intracellular levels of aspartate aminotransferase and alanine aminotransferase (ALT) were detected. The activity of SOD1 decreased over time and the result was supported by the results of western blotting. The transcriptional levels of SOD1 in model cells was significantly higher than untreated cells at 48 h. With the decreased levels of SOD1 and GSH, MDA increased in a time-dependent manner. The content of GSH decreased with time as well, which was also reflected in the results of western blotting. The transcriptional levels of γ-GCLC in all UA-treated groups were lower when compared with those observed in the model group. The activity of ALT tended to increase, depending on the duration of treatment. Treatment with 5 and 10 mg/dl UA had an antioxidative effect on the model cells, and 30 mg/dl UA treatment for 48 h increased OS in the cells.

European contribution to the study of ROS: A summary of the findings and prospects for the future from the COST action BM1203 (EU-ROS)

The European Cooperation in Science and Technology (COST) provides an ideal framework to establish multi-disciplinary research networks. COST Action BM1203 (EU-ROS) represents a consortium of researchers from different disciplines who are dedicated to providing new insights and tools for better understanding redox biology and medicine and, in the long run, to finding new therapeutic strategies to target dysregulated redox processes in various diseases. This report highlights the major achievements of EU-ROS as well as research updates and new perspectives arising from its members. The EU-ROS consortium comprised more than 140 active members who worked together for four years on the topics briefly described below. The formation of reactive oxygen and nitrogen species (RONS) is an established hallmark of our aerobic environment and metabolism but RONS also act as messengers via redox regulation of essential cellular processes. The fact that many diseases have been found to be associated with oxidative stress established the theory of oxidative stress as a trigger of diseases that can be corrected by antioxidant therapy. However, while experimental studies support this thesis, clinical studies still generate controversial results, due to complex pathophysiology of oxidative stress in humans. For future improvement of antioxidant therapy and better understanding of redox-associated disease progression detailed knowledge on the sources and targets of RONS formation and discrimination of their detrimental or beneficial roles is required. In order to advance this important area of biology and medicine, highly synergistic approaches combining a variety of diverse and contrasting disciplines are needed.

Associations of estimated glomerular filtration rate and blood urea nitrogen with incident coronary heart disease: the Dongfeng-Tongji Cohort Study

Estimated glomerular filtration rate (eGFR) has been reported to be associated with risk of incident coronary heart disease (CHD), and blood urea nitrogen (BUN) has been shown to be a strong predictor of mortality in patients with heart failure (HF). However, such epidemiological evidence from Chinese population was still limited. We used Cox proportional-hazards regression models to investigate the associations of eGFR and BUN with risk of incident CHD in the prospective Dongfeng-Tongji (DFTJ) cohort. After fully adjusted for potential confounders, a 10-unit decline in eGFR was associated with higher risk for CHD (hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.01-1.09); compared with individuals with normal eGFR levels (eGFR ≥ 90 ml/min per 1.73 m2), individuals with a mild-to-severe eGFR decline (15 to 60 ml/min per 1.73 m2) were at significantly greater risk for CHD (HR 1.25, 95% CI 1.05-1.48; P = 0.011). Compared with individuals in the lowest tertile of BUN, those in the highest tertile were at significantly greater risk for CHD (HR 1.17, 95% CI 1.03-1.33; P = 0.014). In conclusion, a mild-to-severe decline in eGFR or a raised level of BUN might be associated with increased risk of incident CHD in middle-aged and elderly Chinese populations.