Oxidative stress is progressively enhanced with advancing stages of CKD

A Novel Kidney Failure Prediction Model in Individuals With CKD: Impact of Serum Bilirubin Levels

CONTEXT

Predicting the progression of chronic kidney disease (CKD) to end-stage kidney disease (ESKD) is crucial for improving patient outcomes.

OBJECTIVE

To reveal the highly predictive activity of serum bilirubin levels for the progression of CKD to ESKD, and to develop and validate a novel ESKD prediction model incorporating serum bilirubin levels.

METHODS

We assessed the relative importance of 20 candidate predictors for ESKD, including serum bilirubin levels, in a CKD cohort (15 ≤ estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m2), and subsequently developed a prediction model using the selected variables. The development cohort comprised 4103 individuals with CKD who underwent follow-up at Kyushu University Hospital, Japan, from 2008 to 2018. The primary outcome was incident ESKD, defined as an eGFR < 15 mL/min/1.73 m2, chronic dialysis, or renal transplantation.

RESULTS

The mean follow-up time was 7.0 ± 4.2 years, during which 489 individuals (11.9%) progressed to ESKD. The Cox proportional hazard model selected eGFR, serum bilirubin, proteinuria, age, diabetes, gender, hypertension, serum albumin, and hemoglobin in order of their importance. The predictive performance of the model was optimized by incorporating these 9 variables in discrimination evaluated by time-dependent area under the curve (AUC). This model also demonstrated excellent calibration. Additionally, this model exhibited excellent predictive performance in both discrimination (2-year AUC: 0.943, 5-year AUC: 0.935) and calibration in a validation cohort (n = 2799).

CONCLUSION

Serum bilirubin levels were strong predictors for the progression of CKD to ESKD. Our novel model that incorporates serum bilirubin levels could accurately predict ESKD in individuals with CKD.

Exercise and tissue fibrosis: recent advances in therapeutic potential and molecular mechanisms

Tissue fibrosis represents an aberrant repair process, occurring because of prolonged injury, sustained inflammatory response, or metabolic disorders. It is characterized by an excessive accumulation of extracellular matrix (ECM), resulting in tissue hardening, structural remodeling, and loss of function. This pathological phenomenon is a common feature in the end stage of numerous chronic diseases. Despite the advent of novel therapeutic modalities, including antifibrotic agents, these have only modest efficacy in reversing established fibrosis and are associated with adverse effects. In recent years, a growing body of research has demonstrated that exercise has significant benefits and potential in the treatment of tissue fibrosis. The anti-fibrotic effects of exercise are mediated by multiple mechanisms, including direct inhibition of fibroblast activation, reduction in the expression of pro-fibrotic factors such as transforming growth factor-β (TGF-β) and slowing of collagen deposition. Furthermore, exercise has been demonstrated to assist in maintaining the dynamic equilibrium of tissue repair, thereby indirectly reducing tissue damage and fibrosis. It can also help maintain the dynamic balance of tissue repair by improving metabolic disorders, exerting anti-inflammatory and antioxidant effects, regulating cellular autophagy, restoring mitochondrial function, activating stem cell activity, and reducing cell apoptosis, thereby indirectly alleviating tissue. This paper presents a review of the therapeutic potential of exercise and its underlying mechanisms for the treatment of a range of tissue fibrosis, including cardiac, pulmonary, renal, hepatic, and skeletal muscle. It offers a valuable reference point for non-pharmacological intervention strategies for the comprehensive treatment of fibrotic diseases.

Efficacy of antioxidant intervention and exercise intervention for lipid peroxidation in dialysis patients: a meta-analysis

Background

Lipid peroxidation is a major factor known to contribute to occurrence of cardiovascular events in dialysis patients. This study aims to investigate whether antioxidant interventions can improve lipid peroxidation damage in dialysis patients.

Methods

A comprehensive search in PubMed, Embase, and the Cochrane Library was conducted to identify eligible randomized controlled trials (RCTs) up to June 2024. Endpoints of interest included biomarkers related to Lipid peroxidation. The results from eligible studies were performed using RevMan 5.3 and Stata17.0 software.

Results

A total of 25 RCTs were included, involving eight interventions such as vitamin C supplementation, vitamin E supplementation, vitamin E-coated dialyzer, ω-fatty acid supplementation, curcumin supplementation, pomegranate juice supplementation, exercise intervention, and multiple antioxidant interventions. Outcome indicators included malondialdehyde (MDA) and oxidized low-density lipoprotein (Ox-LDL). The meta-analysis revealed that vitamin E supplementation caused significant reductions in MDA (p = 0.01). Treatment with vitamin E-coated dialyzer markedly decreased MDA levels (p < 0.0001). Curcumin supplementation significantly reduced Ox-LDL levels (p = 0.03). Exercise intervention decreased MDA levels (p < 0.0001). Multiple antioxidant interventions significantly decreased MDA (p = 0.01).

Conclusion

Supplementation of vitamin E, vitamin E-coated dialyzer treatment, curcumin supplementation, exercise intervention, and multiple antioxidant interventions can effectively reduce the level of lipid peroxidation biomarkers in dialysis patients.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO (CRD42023455399).

Relationship between renal oxidative stress levels and disease severity in patients with chronic kidney disease assessed by [Cu-64]ATSM PET/MRI

The purpose of the study was to investigate renal oxidative stress (OS) and its relationship with disease severity in patients with chronic kidney disease (CKD) using positron emission tomography coupled with magnetic resonance imaging (PET/MRI), employing 64Cu-diacetyl-bis(N4-methylthiosemicarbazonate) (64Cu-ATSM) as the PET tracer for OS imaging. Thirty patients with CKD (66.4 ± 8.2 y.o.) and seven healthy controls (HC) subjects (58.3 ± 3.8 y.o.) underwent 64Cu-ATSM PET/MRI. Participants were categorized into three groups based on their estimated glomerular filtration rate (eGFR): HC, mild CKD (stages 2-3a), and advanced CKD (stages 3b-5). All subjects underwent 30-min dynamic PET/MRI starting with the injection of 64Cu-ATSM to evaluate renal blood flow (RBF) and OS levels. RBF (mL/min/100 g) images were calculated from the first 3 min PET data, and standardized uptake value (SUV) images were obtained from delayed frames of 15-30 min after injection. The 64Cu-ATSM SUV images were corrected to RBF-adjusted SUV using individual RBF images to estimate the OS levels of individual kidneys using the following equation: adjusted OS index (aOSi) = (SUV/RBF)x100. Significant correlation was observed between eGFR and RBF (r = 0.81, P < 0.001). RBF in patients with advanced CKD is significantly lower than that in HC (P < 0.001) and patients with mild CKD (P = 0.004). 64Cu-ATSM SUV did not differ significantly among the three groups (P = 0.171). 64Cu-ATSM SUVs did not correlate with creatinine in the HC subjects or in the patients with CKD. However, these values did correlate with eGFR (r = 0.33, P = 0.049) in all subjects, whereas the CKD patients showed no significant correlation. Following RBF correction, the aOSi demonstrated significant correlations with creatinine (r = 0.75, P < 0.001), eGFR (r= -0.65, P < 0.001), and CKD stages (r = 0.57, P < 0.001) in all subjects. This preliminary study has revealed that 64Cu-ATSM PET may provide a estimate of renal OS reasonably in CKD patients noninvasively. Increased aOSi values were correlated with the CKD stages and creatinine levels, suggesting that OS increases with the severity of renal dysfunction.

Advances in kidney disease: pathogenesis and therapeutic targets

Chronic kidney disease (CKD) is a global public health issue characterized by progressive loss of kidney function, of which end-stage kidney disease (ESKD) is the last stage. The global increase in the prevalence of CKD is linked to the increasing prevalence of traditional risk factors, including obesity, hypertension, and diabetes mellitus, as well as metabolic factors, particularly insulin resistance, dyslipidemia, and hyperuricemia. Mortality and comorbidities, such as cardiovascular complications, rise steadily as kidney function deteriorates. Patients who progress to ESKD require long-term kidney replacement therapy, such as transplantation or hemodialysis/peritoneal dialysis. It is currently understood that a crucial aspect of CKD involves persistent, low-grade inflammation. In addition, increased oxidative and metabolic stress, endothelial dysfunction, vascular calcification from poor calcium and phosphate metabolism, and difficulties with coagulation are some of the complex molecular pathways underlying CKD-related and ESKD-related issues. Novel mechanisms, such as microbiome dysbiosis and apolipoprotein L1 gene mutation, have improved our understanding of kidney disease mechanisms. High kidney disease risk of Africa has been linked to APOL1 high-risk alleles. The 3-fold increased risk of ESKD in African Americans compared to European Americans is currently mainly attributed to variants in the APOL1 gene in the chromosome 22q12 locus. Additionally, the role of new therapies such as SGLT2 inhibitors, mineralocorticoid receptor antagonists, and APOL1 channel function inhibitors offers new therapeutic targets in slowing down the progression of chronic kidney disease. This review describes recent molecular mechanisms underlying CKD and emerging therapeutic targets.

The spatiotemporal and paradoxical roles of NRF2 in renal toxicity and kidney diseases

Over 10% of the global population is at risk to kidney disorders. Nuclear factor erythroid-derived 2-related factor 2 (NRF2), a pivotal regulator of redox homeostasis, orchestrates antioxidant response that effectively counters oxidative stress and inflammatory response in a variety of acute pathophysiological conditions, including acute kidney injury (AKI) and early stage of renal toxicity. However, if persistently activated, NRF2-induced transcriptional cascade may disrupt normal cell signaling and contribute to numerous chronic pathogenic processes such as fibrosis. In this concise review, we assembled experimental evidence to reveal the cell- and pathophysiological condition-specific roles of NRF2 in renal chemical toxicity, AKI, and chronic kidney disease (CKD), all of which are closely associated with oxidative stress and inflammation. By incorporating pertinent research findings on NRF2 activators, we dissected the spatiotemporal roles of NRF2 in distinct nephrotoxic settings and kidney diseases. Herein, NRF2 exhibits diverse expression patterns and downstream gene profiles across distinct kidney regions and cell types, and during specific phases of nephropathic progression. These changes are directly or indirectly connected to altered antioxidant defense, damage repair, inflammatory response, regulated cell death and fibrogenesis, culminating ultimately in either protective or deleterious outcomes. The spatiotemporal and paradoxical characteristics of NRF2 in mitigating nephrotoxicity suggest that translational application of NRF2 activation strategy for prevention and interventions of kidney injury are unlikely to be straightforward - right timing and spatial precision must be taken into consideration.

Association of composite dietary antioxidant index with mortality risk among adults with chronic kidney disease in NHANES

At present, the relationship between the intake of antioxidants in food and the mortality rate of patients with chronic kidney disease (CKD), especially the association with the mortality rate of specific causes, is not clear. This study included 6379 adult CKD patients from the National Health and Nutrition Examination Survey (2001-2018). Use the Cox proportional hazards model, restricted cubic spline (RCS) model, and stratified and sensitivity analysis to evaluate the relationship between the Composite Dietary Antioxidant Index (CDAI) and mortality in patients with chronic kidney disease. During the follow-up period, 2381 all-cause deaths were recorded, including 719 deaths from cardiovascular disease, 132 deaths from cerebrovascular disease, and 430 deaths from cancer. We found that compared to the lowest quartile of CDAI, the weighted multivariate hazard ratio of participants in the highest quartile was 0.83 (95% confidence interval: 0.72, 0.96) for all-cause mortality, Cardiovascular mortality was 0.91 (95% confidence interval: 0.70, 1.18), Cerebrovascular death was 0.51 (95% confidence interval: 0.24, 1.07), Death due to cancer was 0.64 (95% confidence interval: 0.45, 0.92). RCS analysis shows a non-linear relationship between CDAI and all-cause mortality and cancer mortality. At the same time, there is no non-linear relationship between CDAI and cardiovascular mortality and cerebrovascular mortality. Stratified analysis shows that race and BMI are influencing factors for CDAI-CKD mortality. Sensitivity analysis confirmed the robustness of the results. Our research findings emphasize the potential advantages of an antioxidant diet in reducing the risk of mortality in CKD patients.

Unraveling Ferroptosis: A New Frontier in Combating Renal Fibrosis and CKD Progression

Chronic kidney disease (CKD) is a global health concern caused by conditions such as hypertension, diabetes, hyperlipidemia, and chronic nephritis, leading to structural and functional kidney injury. Kidney fibrosis is a common outcome of CKD progression, with abnormal fatty acid oxidation (FAO) disrupting renal energy homeostasis and leading to functional impairments. This results in maladaptive repair mechanisms and the secretion of profibrotic factors, and exacerbates renal fibrosis. Understanding the molecular mechanisms of renal fibrosis is crucial for delaying CKD progression. Ferroptosis is a type of discovered an iron-dependent lipid peroxidation-regulated cell death. Notably, Ferroptosis contributes to tissue and organ fibrosis, which is correlated with the degree of renal fibrosis. This study aims to clarify the complex mechanisms of ferroptosis in renal parenchymal cells and explore how ferroptosis intervention may help alleviate renal fibrosis, particularly by addressing the gap in CKD mechanisms related to abnormal lipid metabolism under the ferroptosis context. The goal is to provide a new theoretical basis for clinically delaying CKD progression.

Therapeutic Potential of Oligo-Fucoidan in Mitigating Peritoneal Dialysis-Associated Fibrosis

Peritoneal dialysis (PD) serves as a home-based kidney replacement therapy with increasing utilization across the globe. However, long-term use of high-glucose-based PD solution incites repeated peritoneal injury and inevitable peritoneal fibrosis, thus compromising treatment efficacy and resulting in ultrafiltration failure eventually. In the present study, we utilized human mesothelial MeT-5A cells for the in vitro experiments and a PD mouse model for in vivo validation to study the pathophysiological mechanisms underneath PD-associated peritoneal fibrosis. High-glucose PD solution (Dianeal 4.25%, Baxter) increased protein expression of mesothelial-mesenchymal transition (MMT) markers, such as N-cadherin and α-SMA in MeT-5A cells, whereas it decreased catalase expression and stimulated the production of reactive oxygen species (ROS). Furthermore, macrophage influx and increased serum pro-inflammatory cytokines, such as IL-1β, MCP-1, and TNF-α, were observed in the PD mouse model. Interestingly, we discovered that oligo-fucoidan, an oligosaccharide extract from brown seaweed, successfully prevented PD-associated peritoneal thickening and fibrosis through antioxidant effect, downregulation of MMT markers, and attenuation of peritoneal and systemic inflammation. Hence, oligo-fucoidan has the potential to be developed into a novel preventive strategy for PD-associated peritoneal fibrosis.

Evaluation of oxidative stress in dogs and cats with chronic kidney disease

BACKGROUND

Oxidative stress is a potential contributor to chronic kidney disease (CKD) progression but has not been evaluated in dogs and cats with CKD.

HYPOTHESIS

Oxidative stress is higher in animals with CKD compared with healthy controls and decreases with the advancing CKD stage. The aim of this study was to determine the presence and intensity of oxidative stress in dogs and cats at different CKD stages.

ANIMALS

Sixty dogs and 30 cats with naturally acquired CKD; 10 dogs and 14 cats, healthy controls.

METHODS

Analytical cross-sectional study. Oxidative stress was evaluated by measuring the urinary concentration of F2-isoprostane (uF2-IsoPs) normalized to urinary creatinine.

RESULTS

Urinary F2-isoprostanes normalized to urinary creatinine of healthy dogs and of dogs with CKD Stages 1 to 4 was 3.3 ng/mg, 4.7 ng/mg (range, 1.0-73.4), 2.4 ng/mg (range, 0.4-7.8), 0.52 ng/mg (range, 0.01-2.9), and 0.37 ng/mg (range, 0.01-0.6), respectively. Urinary F2-isoprostanes differed among CKD stages (P < .001), but not compared with controls. uF2-IsoPs of healthy cats and cats with CKD Stages 1 to 4 was 0.68 ng/mg (range, 0.2-1.4), 0.97 ng/mg (range, 0.4-1.8), 0.6 ng/mg (range, 0.002-2.0), 0.94 ng/mg (range, 0.3-2.3), and 0.2 ng/mg (range, 0.01-0.4). Urinary F2-isoprostanes differed among stages (P = .05) but not compared with healthy controls.

CONCLUSION AND CLINICAL IMPORTANCE

Oxidative stress might be present in dogs and cats with CKD. Its magnitude declines as the disease progresses, therefore, it should be considered a potential therapeutic target mostly at the early stages of the disease.

Serum peroxiredoxin-4, a biomarker of oxidative stress, associates with new-onset chronic kidney disease: A population-based cohort study

BACKGROUND

Chronic Kidney Disease (CKD), is often detected late due to its asymptomatic nature in the early stage of the disease. Overproduction of reactive oxygen species contributes to various pathological processes through oxidative stress (OS), impacting on cellular structures and functions with previous studies suggesting a link between OS and CKD progression. This study investigated the association between serum peroxiredoxin-4 (Prx4), a biomarker of oxidative stress, and the development of CKD in the general population.

METHODS

This study featured data from the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) cohort, involving 5341 participants without CKD at baseline who underwent extensive prospective health evaluations. Serum Prx4 levels were quantified using an immunoluminometric assay. The primary outcome was new-onset CKD as defined by the composite of urinary albumin excretion (UAE) > 30 mg/24-h, an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2, or both.

RESULTS

Baseline median Prx4 level was 0.65 [interquartile range (IQR): 0.42-1.04] U/L, median eGFR was 98 [IQR: 87-108] mL/min/1.73 m2, and median UAE was 8.1 [IQR: 6.0-12.1] mg/L. During a median follow-up of 10.4 [IQR: 6.3-11.4] years, 867 (16.2 %) patients developed new-onset CKD. Higher Prx4 levels were significantly associated with an increased risk of CKD (hazard ratio (HR) per doubling: 1.29 [95 % confidence interval (CI): 1.21-1.37], p < 0.001), also after adjustment for risk factors including sex, smoking status, systolic blood pressure, high-sensitive C-reactive protein, chronic heart failure, diabetes mellitus and dyslipidemia (HR per doubling: 1.16 [1.06-1.24], p < 0.001). Sensitivity analyses confirmed the robustness of these findings.

CONCLUSIONS

This study supports the hypothesis that systemic oxidative stress, reflected by higher serum Prx4 levels, is significantly associated with the risk of developing CKD in the general population. These findings suggest that Prx4 could be a valuable biomarker for early risk stratification and prevention strategies in CKD management.

Association of oxidative balance score with all-cause mortality among individuals with chronic kidney disease: a cohort study

BACKGROUND

The Oxidative Balance Score (OBS) is employed for evaluating the body's overall level of oxidative stress. This study aimed to investigate the association between OBS and mortality in individuals with chronic kidney disease (CKD) using a cohort study design.

METHODS

We used data from adult participants(≥ 20 years old) in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. CKD is diagnosed based on the Kidney Disease Improving Global Outcomes (KDIGO) guidelines. OBS, which consists of 16 dietary factors and 4 lifestyle factors, categorized into pro-oxidants and antioxidants, with a total score range of 0 to 40 .The OBS was divided into four quartiles (Q1 to Q4), with Q1 (5-12), Q2 (13-18), Q3 (19-24), and Q4 (25-36). We excluded patients with missing data on OBS, CKD, and key covariates.Cox regression analysis were used to examine the relationship between OBS and all-cause mortality in CKD patients. Sensitivity analyses included subgroup analysis and multiple imputation.

RESULTS

We included a total of 3,984 patients with CKD. During an average follow-up period of 103 months, 1,263 cases (31.7%) of all-cause mortality were recorded. In the fully adjusted model, compared to Q1 the hazard ratios (HRs) and 95% confidence intervals (CIs) for Q4 were as follows: OBS 0.80 (0.68, 0.95) (p = 0.012), dietary OBS 0.78 (0.66, 0.92) (p = 0.003), and lifestyle OBS 0.83 (0.70, 0.99) (p = 0.038). Our sensitivity analyses further confirmed the robustness of these results.

CONCLUSIONS

Higher OBS was negatively correlated with all-cause mortality risk in American adults with CKD.

The Double Burden: Deciphering Chronic Limb-Threatening Ischemia in End-Stage Renal Disease

BACKGROUND

Chronic limb-threatening ischemia (CLTI) in patients with end-stage renal disease (ESRD) poses significant challenges in clinical management due to its unique pathology and poor treatment outcomes. This review calls for a tailored classification and risk assessment for these patients to guide better revascularization choices with early minor amputation as a first-line strategy in advanced stages.

METHODS

This review consolidates key findings from recent literature on CLTI in ESRD, focusing on disease mechanisms, treatment options, and patient outcomes. It evaluates the literature to clarify the decision-making process for managing CLTI in ESRD.

RESULTS

CLTI in ESRD patients often results in worse clinical outcomes, such as nonhealing wounds, increased limb loss, and higher mortality rates. While the literature reveals ongoing debates regarding the optimal revascularization method, recent retrospective studies and meta-analyses suggest potential benefits of endovascular treatment (EVT) over open bypass surgery (OB) in reducing mortality and wound complications, with comparable amputation-free survival rates.

CONCLUSIONS

The selection of revascularization methods in ESRD patients with CLTI is complex, necessitating individualized strategies. The importance of early detection and timely intervention is critical to decelerate disease progression and improve revascularization outcomes. There is a shift in these treatment strategies toward less invasive endovascular procedures, acknowledging the limitations these patients face with open revascularization surgeries. Considering early minor amputations after revascularization could prevent worse consequences, reflecting a shift in the approach to managing CLTI in ESRD patients.

Association of the oxidative balance score and chronic kidney disease: insights from the national health and nutrition examination survey 2009-2018

Introduction

Oxidative stress plays a pivotal role in the pathogenesis of chronic kidney disease (CKD). The oxidative balance score (OBS) was devised to quantify the overall oxidative state, integrating pro-oxidant and antioxidant influences from both dietary intake and lifestyle practices. The aim of this study was to delve into the relationship between the OBS and CKD within the adult population of the United States.

Methods

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2009-2018, we derived the OBS from 16 dietary and four lifestyle factors. We employed weighted multivariate regression to probe the link between OBS and CKD. Additionally, we undertook subgroup analyses and applied Restricted Cubic Spline Regression (RCS) for further data analyses.

Results

This study encompassed 19,444 participants. Logistic regression analysis consistently demonstrated a protective effect of higher OBS on CKD. In Model 3, each unit increase in OBS was associated with a 2% reduction in the risk of CKD (95% CI: 0.97-0.99, p < 0.001) and a 4% reduction in the risk of reduced estimated glomerular filtration rate (eGFR) (95% CI: 0.95-0.98, p < 0.001). The highest OBS quintile (Q4) also showed significant reductions in the risk of CKD (OR: 0.66, 95% CI: 0.53-0.82, p < 0.001) and reduced eGFR (OR: 0.51, 95% CI: 0.37-0.69, p < 0.001) in Model 3. RCS analysis revealed a linear relationship between OBS and CKD. Subgroup analyses indicated significant associations between OBS and CKD in most subgroups, except for those without hypertension or with cardiovascular disease. Additionally, interaction analyses demonstrated that age, hypertension, and diabetes significantly modify the association between OBS and CKD risk.

Conclusion

An elevated OBS, reflecting a predominance of antioxidants, correlates with a diminished CKD risk in the American adult demographic. These insights emphasize the potential influence of oxidative equilibrium on the development of CKD.

Living donors kidney transplantation and oxidative stress: Nitric oxide as a predictive marker of graft function

BACKGROUND

Glomerular filtration rate is the best indicator of renal function and a predictor of graft and patient survival after kidney transplantation.

METHODS

In a single-centre prospective analysis, we assessed the predictive performances of 4 oxidative stress biomarkers in estimating graft function at 6 months and 1 year after kidney transplantation from living donors. Blood samples were achieved on days (D-1, D1, D2, D3, D6 and D8), months (M1, M3 and M6) and after one year (1Y). For donors, a blood sample was collected on D-1. Malondialdehyde (MDA), nitric oxide (NO), glutathione s-transferase (GST), myeloperoxydase (MPO), and creatinine (Cr) were measured by spectrophotometric essays. The estimated glomerular filtration rate by the modification of diet in renal disease equation (MDRD-eGFR) was used to assess renal function in 32 consecutive donor-recipient pairs. Pearson's and Spearman's correlations have been applied to filter out variables and covariables that can be used to build predictive models of graft function at six months and one year. The predictive performances of NO and MPO were tested by multivariable stepwise linear regression to estimate glomerular filtration rate at six months.

RESULTS

Three models with the highest coefficients of determination stand out, combining the two variables nitric oxide at day 6 and an MDRD-eGFR variable at day 6 or MDRD-eGFR at day 21 or MDRD-eGFR at 3 months, associated for the first two models or not for the third model with donor age as a covariable (P = 0.000, r2 = 0.599, r2adj = 0.549; P = 0.000, r2 = 0.548, r2adj = 0.497; P = 0.000, r2 = 0.553, r2adj = 0.517 respectively).

CONCLUSION

Quantification of nitric oxide at day six could be useful in predicting graft function at six months in association with donor age and the estimated glomerular filtration rate in recipient at day 6, day 21 and 3 months after transplantation.

Proteomic Analysis Identifies Dysregulated Proteins in Albuminuria: A South African Pilot Study

Albuminuria may precede decreases in the glomerular filtration rate (GFR) and both tests are insensitive predictors of early stages of kidney disease. Our aim was to characterise the urinary proteome in black African individuals with albuminuria and well-preserved GFR from South Africa. This case-controlled study compared the urinary proteomes of 52 normoalbuminuric (urine albumin: creatinine ratio (uACR) < 3 mg/mmol) and 56 albuminuric (uACR ≥ 3 mg/mmol) adults of black African ethnicity. Urine proteins were precipitated, reduced, alkylated, digested, and analysed using an Evosep One LC (Evosep Biosystems, Odense, Denmark) coupled to a Sciex 5600 Triple-TOF (Sciex, Framingham, MA, USA) in data-independent acquisition mode. The data were searched on SpectronautTM 15. Differentially abundant proteins (DAPs) were filtered to include those with a ≥2.25-fold change and a false discovery rate ≤ 1%. Receiver-operating characteristic curves were used to assess the discriminating abilities of proteins of interest. Pathway analysis was performed using Enrichr software. As expected, the albuminuric group had higher uACR (7.9 vs. 0.55 mg/mmol, p < 0.001). The median eGFR (mL/min/1.73 m2) showed no difference between the groups (111 vs. 114, p = 0.707). We identified 80 DAPs in the albuminuria group compared to the normoalbuminuria group, of which 59 proteins were increased while 21 proteins were decreased in abundance. We found 12 urinary proteins with an AUC > 0.8 and a p < 0.001 in the multivariate analysis. Furthermore, an 80-protein model was developed that showed a high AUC ˃ 0.907 and a predictive accuracy of 91.3% between the two groups. Pathway analysis found that the DAPs were involved in insulin growth factor (IGF) functions, innate immunity, platelet degranulation, and extracellular matrix organization. In albuminuric individuals with a well-preserved eGFR, pathways involved in preventing the release and uptake of IGF by insulin growth factor binding protein were significantly enriched. These proteins are indicative of a homeostatic imbalance in a variety of cellular processes underlying renal dysfunction and are implicated in chronic kidney disease.

Antioxidative effects of molybdenum and its association with reduced prevalence of hyperuricemia in the adult population

The relationship between molybdenum and kidney-related disease outcomes, including hyperuricemia, is not well investigated. This study aims to determine whether molybdenum and its antioxidative property are associated with systemic inflammation and kidney-related disease parameters including hyperuricemia. Urinary molybdenum's epidemiological relationship to hyperuricemia and kidney-disease related outcomes was evaluated in 15,370 adult participants in the National Health and Nutrition Examination Survey (NHANES) collected between 1999 and 2016. Individuals' urinary molybdenum levels were corrected to their urinary creatinine concentrations. The association between urinary molybdenum-to-creatinine ratio and kidney-disease related outcomes were assessed by multivariable linear and logistic regression analyses, adjusting for covariates including age, sex, ethnicity, diabetes mellitus, hypertension, body mass index, and estimated glomerular filtration rate. Antimony and tungsten were used as control trace metals. Experimentally, HK-2 cell was used to assess molybdenum's antioxidative properties. HK-2 cells were challenged with H2O2-induced oxidative stress. Oxidative stress was measured using a fluorescent microplate assay for reactive oxygen species (ROS) and antioxidation levels were assessed by measuring the expression of manganese superoxide dismutase. In the adult NHANES population, urinary molybdenum-to-creatinine ratio was significantly associated with decreased serum uric acid (β, -0.119; 95% CI, -0.148 to -0.090) concentrations, and decreased prevalence of hyperuricemia (OR, 0.73; 95% CI, 0.64-0.83) and gout (OR, 0.71; 95% CI, 0.52-0.94). Higher urinary molybdenum levels were associated with lower levels of systemic oxidative stress (gamma-glutamyltransferase levels; β, -0.052; 95% CI, -0.067 to -0.037) and inflammation (C-reactive protein levels; β, -0.184; 95% CI, -0.220 to -0.148). In HK-2 cells under H2O2-induced oxidative stress, molybdenum upregulated manganese superoxide dismutase expression and decreased oxidative stress. Urinary molybdenum levels are associated with decreased prevalence of hyperuricemia and gout in adult population. Molybdenum's antioxidative properties might have acted as an important mechanism for the reduction of systemic inflammation, ROS, and uric acid levels.

Understanding the Role of Sex Hormones in Cardiovascular Kidney Metabolic Syndrome: Toward Personalized Therapeutic Approaches

Cardiovascular kidney metabolic (CKM) syndrome represents a complex interplay of cardiovascular disease (CVD), chronic kidney disease (CKD), and metabolic comorbidities, posing a significant public health challenge. Gender exerts a critical influence on CKM syndrome, affecting the disease severity and onset through intricate interactions involving sex hormones and key physiological pathways such as the renin-angiotensin system, oxidative stress, inflammation, vascular disease and insulin resistance. It is widely known that beyond the contribution of traditional risk factors, men and women exhibit significant differences in CKM syndrome and its components, with distinct patterns observed in premenopausal women and postmenopausal women compared to men. Despite women generally experiencing a lower incidence of CVD, their outcomes following cardiovascular events are often worse compared to men. The disparities also extend to the treatment approaches for kidney failure, with a higher prevalence of dialysis among men despite women exhibiting higher rates of CKD. The impact of endogenous sex hormones, the correlations between CKM and its components, as well as the long-term effects of treatment modalities using sex hormones, including hormone replacement therapies and gender-affirming therapies, have drawn attention to this topic. Current research on CKM syndrome is hindered by the scarcity of large-scale studies and insufficient integration of gender-specific considerations into treatment strategies. The underlying mechanisms driving the gender disparities in the pathogenesis of CKM syndrome, including the roles of estrogen, progesterone and testosterone derivatives, remain poorly understood, thus limiting their application in personalized therapeutic interventions. This review synthesizes existing knowledge to clarify the intricate relationship between sex hormones, gender disparities, and the progression of CVD within CKM syndrome. By addressing these knowledge gaps, this study aims to guide future research efforts and promote tailored approaches for effectively managing CKD syndrome.

Potentials of Natural Antioxidants in Reducing Inflammation and Oxidative Stress in Chronic Kidney Disease

Chronic kidney disease (CKD) presents a substantial global public health challenge, with high morbidity and mortality. CKD patients often experience dyslipidaemia and poor glycaemic control, further exacerbating inflammation and oxidative stress in the kidney. If left untreated, these metabolic symptoms can progress to end-stage renal disease, necessitating long-term dialysis or kidney transplantation. Alleviating inflammation responses has become the standard approach in CKD management. Medications such as statins, metformin, and GLP-1 agonists, initially developed for treating metabolic dysregulation, demonstrate promising renal therapeutic benefits. The rising popularity of herbal remedies and supplements, perceived as natural antioxidants, has spurred investigations into their potential efficacy. Notably, lactoferrin, Boerhaavia diffusa, Amauroderma rugosum, and Ganoderma lucidum are known for their anti-inflammatory and antioxidant properties and may support kidney function preservation. However, the mechanisms underlying the effectiveness of Western medications and herbal remedies in alleviating inflammation and oxidative stress occurring in renal dysfunction are not completely known. This review aims to provide a comprehensive overview of CKD treatment strategies and renal function preservation and critically discusses the existing literature's limitations whilst offering insight into the potential antioxidant effects of these interventions. This could provide a useful guide for future clinical trials and facilitate the development of effective treatment strategies for kidney functions.

Oleanolic acid and its analogues: promising therapeutics for kidney disease

Kidney diseases pose a significant threat to human health due to their high prevalence and mortality rates. Worryingly, the clinical use of drugs for kidney diseases is associated with more side effects, so more effective and safer treatments are urgently needed. Oleanolic acid (OA) is a common pentacyclic triterpenoid that is widely available in nature and has been shown to have protective effects in kidney disease. However, comprehensive studies on its role in kidney diseases are still lacking. Therefore, this article first explores the botanical sources, pharmacokinetics, derivatives, and safety of OA, followed by a summary of the anti-inflammatory, immunomodulatory, anti-oxidative stress, autophagy-enhancing, and antifibrotic effects of OA and its analogues in renal diseases, and an analysis of the molecular mechanisms, aiming to provide further insights for the development of novel drugs for the treatment of kidney diseases.

Oxidative stress in patients with coronavirus disease and end-stage renal disease: a pilot study

BACKGROUND

Oxidative stress, an imbalance between reactive oxygen species production and antioxidant capacity, increases in patients with coronavirus disease (COVID-19) or renal impairment. We investigated whether combined COVID-19 and end-stage renal disease (ESRD) would increase oxidative stress levels compared to each disease alone.

METHODS

Oxidative stress was compared among three groups. Two groups comprised patients with COVID-19 referred to the hospital with or without renal impairment (COVID-ESRD group [n = 18]; COVID group [n = 17]). The third group (ESRD group [n = 18]) comprised patients without COVID-19 on maintenance hemodialysis at a hospital.

RESULTS

The total oxidative stress in the COVID-ESRD group was lower than in the COVID group (p = 0.047). The total antioxidant status was higher in the COVID-ESRD group than in the ESRD (p < 0.001) and COVID (p < 0.001) groups after controlling for covariates. The oxidative stress index was lower in the COVID-ESRD group than in the ESRD (p = 0.001) and COVID (p < 0.001) groups. However, the three oxidative parameters did not differ significantly between the COVID and COVID-ESRD groups.

CONCLUSIONS

The role of reactive oxygen species in the pathophysiology of COVID-19 among patients withESRD appears to be non-critical. Therefore, the provision of supplemental antioxidants may not confer a therapeutic advantage, particularly in cases of mild COVID-19 in ESRD patients receiving hemodialysis. Nonetheless, this area merits further research.

Oxidative damage in the gastrocnemius predicts long-term survival in patients with peripheral artery disease

Patients with peripheral artery disease (PAD) have increased mortality rates and a myopathy in their affected legs which is characterized by increased oxidative damage, reduced antioxidant enzymatic activity and defective mitochondrial bioenergetics. This study evaluated the hypothesis that increased levels of oxidative damage in gastrocnemius biopsies from patients with PAD predict long-term mortality rates. Oxidative damage was quantified as carbonyl adducts in myofibers of the gastrocnemius of PAD patients. The oxidative stress data were grouped into tertiles and the 5-year, all-cause mortality for each tertile was determined by Kaplan-Meier curves and compared by the Modified Peto test. A Cox-regression model was used to control the effects of clinical characteristics. Results were adjusted for age, sex, race, body mass index, ankle-brachial index, smoking, physical activity, and comorbidities. Of the 240 study participants, 99 died during a mean follow up of 37.8 months. Patients in the highest tertile of oxidative damage demonstrated the highest 5-year mortality rate. The mortality hazard ratios (HR) from the Cox analysis were statistically significant for oxidative damage (lowest vs middle tertile; HR = 6.33; p = 0.0001 and lowest vs highest; HR = 8.37; p < 0.0001). Survival analysis of a contemporaneous population of PAD patients identifies abundance of carbonyl adducts in myofibers of their gastrocnemius as a predictor of mortality rate independently of ankle-brachial index, disease stage and other clinical and myopathy-related covariates.

Exercise in Diabetic Nephropathy: Protective Effects and Molecular Mechanism

Diabetic nephropathy (DN) is a serious complication of diabetes, and its progression is influenced by factors like oxidative stress, inflammation, cell death, and fibrosis. Compared to drug treatment, exercise offers a cost-effective and low-risk approach to slowing down DN progression. Through multiple ways and mechanisms, exercise helps to control blood sugar and blood pressure and reduce serum creatinine and albuminuria, thereby alleviating kidney damage. This review explores the beneficial effects of exercise on DN improvement and highlights its potential mechanisms for ameliorating DN. In-depth understanding of the role and mechanism of exercise in improving DN would pave the way for formulating safe and effective exercise programs for the treatment and prevention of DN.

Updates on New Therapies for Patients with CKD

Individuals diagnosed with chronic kidney disease (CKD) continue to increase globally. This group of patients experience a disproportionately higher risk of cardiovascular (CV) events compared to the general population. Despite multiple guidelines-based medical management, patients with CKD continue to experience residual cardiorenal risk. Several potential mechanisms explain this excessive CV risk observed in individuals with CKD. Several new drugs have become available that could potentially transform CKD care, given their efficacy in this patient population. Nevertheless, use of these drugs presents certain benefits and challenges that are often underrecognized by prescribing these drugs. In this review, we aim to provide a brief discussion about CKD pathophysiology, limiting our discussion to recent published studies. We also explore benefits and limitations of newer drugs, including angiotensin receptor/neprilysin inhibitors (ARNI), sodium glucose transporter 2 inhibitors (SGLT2i), glucagon-like peptides-1 (GLP-1) agonists and finerenone in patients with CKD. Despite several articles covering this topic, our review provides an algorithm where subgroups of patients with CKD might benefit the most from such drugs based on the selection criteria of the landmark trials. Patients with CKD who have nephrotic range proteinuria beyond 5000 mg/g, or those with poorly controlled blood pressure (systolic ≥160 mm Hg or diastolic ≥100 mm Hg) remain understudied.

Kidney Transplant Recipients Show Limited Lung Diffusion Capacity but Similar Hydrogen Peroxide Exhalation as Healthy Matched Volunteers: A Pilot Study

Patients with end-stage chronic kidney disease show higher systemic oxidative stress and exhale more hydrogen peroxide (H2O2) than healthy controls. Kidney transplantation reduces oxidative stress and H2O2 production by blood polymorphonuclear leukocytes (PMNs). Kidney transplant recipients (KTRs) may be predisposed to an impairment of lung diffusing capacity due to chronic inflammation. Lung function and H2O2 concentration in the exhaled breath condensate (EBC) were compared in 20 KTRs with stable allograft function to 20 healthy matched controls. Serum interleukin eight (IL-8) and C-reactive protein (CRP), blood cell counts, and spirometry parameters did not differ between groups. However, KTRs showed lower total lung diffusing capacity for carbon monoxide, corrected for hemoglobin concentration (TLCOc), in comparison to healthy controls (92.1 ± 11.5% vs. 102.3 ± 11.9% of predicted, p = 0.009), but similar EBC H2O2 concentration (1.63 ± 0.52 vs. 1.77 ± 0.50 µmol/L, p = 0.30). The modality of pre-transplant renal replacement therapy had no effect on TLCOc and EBC H2O2. TLCOc did not correlate with time after transplantation. In this study, TLCOc was less reduced in KTRs in comparison to previous reports. We suggest this fact and the non-elevated H2O2 exhalation exhibited by KTRs, may result perhaps from the evolution of the immunosuppressive therapy.

Cardiomyopathy in chronic kidney disease: clinical features, biomarkers and the contribution of murine models in understanding pathophysiology

The cardiorenal syndrome (CRS) is described as a multi-organ disease encompassing bidirectionally heart and kidney. In CRS type 4, chronic kidney disease (CKD) leads to cardiac injury. Different pathological mechanisms have been identified to contribute to the establishment of CKD-induced cardiomyopathy, including a neurohormonal dysregulation, disturbances in the mineral metabolism and an accumulation of uremic toxins, playing an important role in the development of inflammation and oxidative stress. Combined, this leads to cardiac dysfunction and cardiac pathophysiological and morphological changes, like left ventricular hypertrophy, myocardial fibrosis and cardiac electrical changes. Given that around 80% of dialysis patients suffer from uremic cardiomyopathy, the study of cardiac outcomes in CKD is clinically highly relevant. The present review summarizes clinical features and biomarkers of CKD-induced cardiomyopathy and discusses underlying pathophysiological mechanisms recently uncovered in the literature. It discloses how animal models have contributed to the understanding of pathological kidney-heart crosstalk, but also provides insights into the variability in observed effects of CKD on the heart in different CKD mouse models, covering both "single hit" as well as "multifactorial hit" models. Overall, this review aims to support research progress in the field of CKD-induced cardiomyopathy.

A Study of Oxidative Stress, Inflammation, and Endothelial Dysfunction in Diabetic and Nondiabetic Chronic Kidney Disease Pre-Dialysis Patients

Background

Oxidative stress, inflammation, and endothelial dysfunction represent a key triad for the development and progression of atherosclerosis. Due to chronic low-grade inflammation in chronic kidney disease (CKD), concentrations of various inflammatory, endothelial, and oxidative stress markers are elevated, increasing the risk of atherosclerosis. The present study was undertaken to compare oxidative stress, inflammation, and endothelial dysfunction in diabetic and nondiabetic CKD pre-dialysis patients.

Materials and Methods

This was an observational study on 120 CKD pre-dialysis patients: 60 with diabetes and 60 without diabetes. Markers of oxidative stress were measured in blood - malondialdehyde (MDA), ferric reducing ability of plasma (FRAP), paroxonase-1 (PON-1), ischemia-modified albumin (IMA); inflammation - interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP); and endothelial dysfunction - nitric oxide (NO), carotid wall intima-media thickness (CIMT). Comparisons between the two groups for continuous variables were made with the Student's unpaired t-test or Mann-Whitney test and for categorical values with χ2-test, as appropriate.

Results

MDA, IMA, IL-6, hsCRP, NO, and CIMT were significantly higher, while FRAP and PON-1 were significantly lower in the diabetic group when compared to nondiabetic group (P < 0.001). The number of atherosclerotic plaques was also significantly higher in the diabetic group compared to nondiabetic group.

Conclusion

Our study showed increased oxidative stress, inflammation, endothelial dysfunction, and atherosclerosis in diabetic CKD pre-dialysis patients when compared to nondiabetic CKD pre-dialysis patients and in late stages when compared to early stages of CKD in both groups, indicating increased cardiovascular risk in late stages and diabetic CKD pre-dialysis patients.

Epithelial Transport in Disease: An Overview of Pathophysiology and Treatment

Epithelial transport is a multifaceted process crucial for maintaining normal physiological functions in the human body. This comprehensive review delves into the pathophysiological mechanisms underlying epithelial transport and its significance in disease pathogenesis. Beginning with an introduction to epithelial transport, it covers various forms, including ion, water, and nutrient transfer, followed by an exploration of the processes governing ion transport and hormonal regulation. The review then addresses genetic disorders, like cystic fibrosis and Bartter syndrome, that affect epithelial transport. Furthermore, it investigates the involvement of epithelial transport in the pathophysiology of conditions such as diarrhea, hypertension, and edema. Finally, the review analyzes the impact of renal disease on epithelial transport and highlights the potential for future research to uncover novel therapeutic interventions for conditions like cystic fibrosis, hypertension, and renal failure.

Human peritoneal tight junction, transporter and channel expression in health and kidney failure, and associated solute transport

Next to the skin, the peritoneum is the largest human organ, essentially involved in abdominal health and disease states, but information on peritoneal paracellular tight junctions and transcellular channels and transporters relative to peritoneal transmembrane transport is scant. We studied their peritoneal localization and quantity by immunohistochemistry and confocal microscopy in health, in chronic kidney disease (CKD) and on peritoneal dialysis (PD), with the latter allowing for functional characterizations, in a total of 93 individuals (0-75 years). Claudin-1 to -5, and -15, zonula occludens-1, occludin and tricellulin, SGLT1, PiT1/SLC20A1 and ENaC were consistently detected in mesothelial and arteriolar endothelial cells, with age dependent differences for mesothelial claudin-1 and arteriolar claudin-2/3. In CKD mesothelial claudin-1 and arteriolar claudin-2 and -3 were more abundant. Peritonea from PD patients exhibited increased mesothelial and arteriolar claudin-1 and mesothelial claudin-2 abundance and reduced mesothelial and arteriolar claudin-3 and arteriolar ENaC. Transperitoneal creatinine and glucose transport correlated with pore forming arteriolar claudin-2 and mesothelial claudin-4/-15, and creatinine transport with mesothelial sodium/phosphate cotransporter PiT1/SLC20A1. In multivariable analysis, claudin-2 independently predicted the peritoneal transport rates. In conclusion, tight junction, transcellular transporter and channel proteins are consistently expressed in peritoneal mesothelial and endothelial cells with minor variations across age groups, specific modifications by CKD and PD and distinct associations with transperitoneal creatinine and glucose transport rates. The latter deserve experimental studies to demonstrate mechanistic links.Clinical Trial registration: The study was performed according to the Declaration of Helsinki and is registered at www.clinicaltrials.gov (NCT01893710).

The effect of aerobic exercise on oxidative stress in patients with chronic kidney disease: a systematic review and meta-analysis with trial sequential analysis

PURPOSE

The purpose of this study was to investigate how aerobic exercise affects oxidative stress (OS) in patients with chronic kidney disease (CKD).

METHODS

Retrieval dates range from the date the database was established to 19 July 2023, without languages being restricted. A meta-analysis and sensitivity analysis were conducted using RevMan 5.3 and Stata 16.0.

RESULTS

The meta-analysis showed that, compared to usual activity or no exercise, aerobic exercise significantly reduced the oxidative markers malondialdehyde (MDA) (mean differences (MD) - 0.96 (95% CI -1.33, - 0.59); p < 0.00001), advanced oxidation protein product (AOPP) (MD - 3.49 (95% CI - 5.05, - 1.93); p < 0.00001), F2-isoprostanes (F2-iso) (MD - 11.02 (95% CI - 17.79, - 4.25); p = 0.001). Aerobic exercise also increased the antioxidant marker superoxide dismutase (SOD) in CKD patients (standardized mean differences (SMD) 1.30 (95% CI 0.56, 2.04); p = 0.0005). Subgroup analysis showed a significant increase in glutathione peroxidase (GPX) in patients aged ≥60 years (SMD 2.11 (95% CI 1.69, 2.54); p < 0.00001). The change in total antioxidant capacity (TAC) after aerobic exercise was insignificant in patients with CKD. The trial sequential analysis supported aerobic exercise's effectiveness in improving MDA, SOD, AOPP, and F2-iso in patients with CKD.

CONCLUSION

The results of this review suggest that aerobic exercise improves OS indicators (MDA, SOD, AOPP, and F2-iso) in CKD patients compared to conventional treatment or no exercise and that the effects on GPX and TAC indicators need further confirmation. For better validation of benefits and exploration of the best aerobic exercise regimen to improve OS status with CKD, further studies with high methodological quality and large sample sizes are needed.

A review of research progress on mechanisms of peritoneal fibrosis related to peritoneal dialysis

Peritoneal dialysis (PD) is an effective alternative treatment for patients with end-stage renal disease (ESRD) and is increasingly being adopted and promoted worldwide. However, as the duration of peritoneal dialysis extends, it can expose problems with dialysis inadequacy and ultrafiltration failure. The exact mechanism and aetiology of ultrafiltration failure have been of great concern, with triggers such as biological incompatibility of peritoneal dialysis solutions, uraemia toxins, and recurrent intraperitoneal inflammation initiating multiple pathways that regulate the release of various cytokines, promote the transcription of fibrosis-related genes, and deposit extracellular matrix. As a result, peritoneal fibrosis occurs. Exploring the pathogenic factors and molecular mechanisms can help us prevent peritoneal fibrosis and prolong the duration of Peritoneal dialysis.

New potential biomarkers for early chronic kidney disease diagnosis in patients with different glucose tolerance status

Background

The purpose of the present study was to investigate the role of oxidative stress, platelet activation, and endocan levels in renal dysfunction in normal glucose tolerance (NGT) patients with 1-h plasma glucose values ≥155 mg/dl (NGT ≥ 155), compared to NGT < 155, impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM) newly diagnosed subjects. We enlisted 233 patients subjected to an oral glucose tolerance test (OGTT).

Materials and methods

The serum levels of platelet activation (glycoprotein VI and sP-selectin), oxidative stress biomarkers (8-isoprostane and Nox-2), and endocan were evaluated using an ELISA test.

Results

Among NGT < 155 patients and the T2DM group, there was a statistically significant increase in 8-isoprostane (p < 0.0001), Nox-2 (p < 0.0001), glycoprotein VI (p < 0.0001), and sP-selectin (p < 0.0001) serum levels. Higher serum endocan levels were found with the worsening of metabolic profile (p < 0.0001); specifically, NGT ≥ 155 patients presented higher serum endocan values when compared to NGT < 155 patients (p < 0.0001). From the multivariate linear regression analysis, 1-h glucose resulted in the major predictor of estimated glomerular filtration rate (e-GFR) justifying 23.6% of its variation (p < 0.0001); 8-isoprostane and Nox-2 added respectively another 6.0% (p < 0.0001) and 3.2% (p = 0.001).

Conclusion

Our study confirmed the link between 1-h post-load glucose ≥155 mg/dl during OGTT and the possible increased risk for chronic kidney disease (CKD) in newly diagnosed patients. The novelty is that we demonstrated a progressive increase in oxidative stress, platelet activation, and serum endocan levels with the worsening of metabolic profile, which becomes evident early during the progression of CKD.

A Rodent Model of Human-Dose-Equivalent 5-Fluorouracil: Toxicity in the Liver, Kidneys, and Lungs

5-Fluorouracil (5-FU) is a chemotherapy drug widely used to treat a range of cancer types, despite the recurrence of adverse reactions. Therefore, information on its side effects when administered at a clinically recommended dose is relevant. On this basis, we examined the effects of the 5-FU clinical treatment on the integrity of the liver, kidneys, and lungs of rats. For this purpose, 14 male Wistar rats were divided into treated and control groups and 5-FU was administered at 15 mg/kg (4 consecutive days), 6 mg/kg (4 alternate days), and 15 mg/kg on the 14th day. On the 15th day, blood, liver, kidney, and lung samples were collected for histological, oxidative stress, and inflammatory evaluations. We observed a reduction in the antioxidant markers and an increase in lipid hydroperoxides (LOOH) in the liver of treated animals. We also detected elevated levels of inflammatory markers, histological lesions, apoptotic cells, and aspartate aminotransferase. Clinical treatment with 5-FU did not promote inflammatory or oxidative alterations in the kidney samples; however, histological and biochemical changes were observed, including increased serum urea and uric acid. 5-FU reduces endogenous antioxidant defenses and increases LOOH levels in the lungs, suggesting oxidative stress. Inflammation and histopathological alterations were also detected. The clinical protocol of 5-FU promotes toxicity in the liver, kidneys, and lungs of healthy rats, resulting in different levels of histological and biochemical alterations. These results will be useful in the search for new adjuvants to attenuate the adverse effects of 5-FU in such organs.

Nontraditional Risk Factors for Progression Through Chronic Kidney Disease Risk Categories: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND

There may be nontraditional pathways of chronic kidney disease (CKD) progression that are complementary to classical pathways. Therefore, we aimed to examine nontraditional risk factors for incident CKD and its progression.

METHODS

We used the generally healthy population (n = 4382) starting at age 27-41 years in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, which is an observational longitudinal study. Nontraditional risk factors included forced vital capacity, inflammation, serum urate, and serum carotenoids. CKD risk category was classified using the estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) measured in 1995-1996 and repeated every 5 years for 20 years: No CKD, low risk, moderate risk, high risk, and very high risk.

RESULTS

At baseline, 84.8% had no CKD (eGFR ≥60 mL/min/1.73 m2 and UACR <10 mg/g), 10.3% were in the low risk (eGFR ≥60 and UACR 10-29), and 4.9% had CKD (eGFR <60 and/or UACR ≥ 30). Nontraditional risk factors were significantly associated with the progression of CKD to higher categories. Hazard ratios per standard deviation of the predictor for incident CKD and its progression from the No CKD and low and moderate risk into CKD were inverse for forced vital capacity and serum carotenoids and positive for serum urate, GlycA, and C-reactive protein, the first 3 even after adjustment for conventional risk factors.

CONCLUSION

Several nontraditional markers were significantly associated with an increased risk of progression to higher CKD categories in generally healthy young to middle-aged adults.

Distinct dietary risk factors for incident osteoporotic fractures in early and late postmenopausal phase women

INTRODUCTION

Available evidence on favorable nutritional factors for preventing osteoporosis remains controversial. Considering the recent increases in life expectancy, we investigated the relationship between incident osteoporotic fractures and dietary habits in early and late postmenopausal phase women.

MATERIALS AND METHODS

Subjects were Japanese postmenopausal outpatients recruited at a primary care institution in Nagano Prefecture (Nagano Cohort Study). Patients with critical or acute illness or secondary osteoporosis were not included in this study. In total, 1,071 participants were prospectively followed for a mean of 5.8 years. The cohort was divided into early (≤ 70 years) and late (> 70 years) postmenopausal phases based on median age. Dietary nutrient intake was estimated by the food frequency questionnaire method. According to baseline nutrient intake characteristics, we focused on protein/energy and Ca/NaCl intake ratios, which were also divided by the median values.

RESULTS

Kaplan-Meier plots revealed a significantly higher occurrence of fractures for the high protein/energy intake group in early postmenopausal subjects (P = 0.009), whereas the low Ca/NaCl intake group in late postmenopausal subjects exhibited a significantly earlier occurrence of fractures (P = 0.002). Multivariate Cox regression uncovered significant independent risks of higher protein/energy (HR 1.35; 95% CI 1.04-1.74) and lower Ca/NaCl (HR 0.79; 95% CI 0.63-0.99) intake ratios for incident osteoporotic fractures in the early and late postmenopausal cohorts, respectively.

CONCLUSION

Distinct dietary risk factors for osteoporotic fractures were identified in early and late postmenopausal phase women. Appropriate nutritional guidance according to patient age will be important for maintaining bone health and quality of life.

Effects of Antioxidant Combinations on the Renal Toxicity Induced Rats by Gold Nanoparticles

This study investigated some possible mechanisms underlying the nephrotoxic effect of gold nanoparticles (AuNPs) in rats and compared the protective effects of selected known antioxidants-namely, melanin, quercetin (QUR), and α-lipoic acid (α-LA). Rats were divided into five treatment groups (eight rats per group): control, AuNPs (50 nm), AuNPs + melanin (100 mg/kg), AuNPs + QUR (200 mg/kg), and AuNPs + α-LA (200 mg/kg). All treatments were administered i.p., daily, for 30 days. AuNPs promoted renal glomerular and tubular damage and impaired kidney function, as indicated by the higher serum levels of creatinine (Cr), urinary flow, and urea and albumin/Cr ratio. They also induced oxidative stress by promoting mitochondrial permeability transition pore (mtPTP) opening, the expression of NOX4, increasing levels of malondialdehyde (MDA), and suppressing glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). In addition, AuNPs induced renal inflammation and apoptosis, as evidenced by the increase in the total mRNA and the cytoplasmic and nuclear levels of NF-κB, mRNA levels of Bax and caspase-3, and levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Treatment with melanin, QUR, and α-lipoic acid (α-LA) prevented the majority of these renal damage effects of AuNPs and improved kidney structure and function, with QUR being the most powerful. In conclusion, in rats, AuNPs impair kidney function by provoking oxidative stress, inflammation, and apoptosis by suppressing antioxidants, promoting mitochondrial uncoupling, activating NF-κB, and upregulating NOX4. However, QUR remains the most powerful drug to alleviate this toxicity by reversing all of these mechanisms.

Chronic Kidney Disease as a Comorbidity in Heart Failure

Heart failure (HF) is one of the greatest problems in healthcare and it often coexists with declining renal function. The pathophysiology between the heart and the kidneys is bidirectional. Common mechanisms leading to the dysfunction of these organs result in a vicious cycle of cardiorenal deterioration. It is also associated with difficulties in the treatment of aggravating HF and chronic kidney disease (CKD) and, as a consequence, recurrent hospitalizations and death. As the worsening of renal function has an undeniably negative impact on the outcomes in patients with HF, searching for new treatment strategies and identification of biomarkers is necessary. This review is focused on the pathomechanisms in chronic kidney disease in patients with HF and therapeutic strategies for co-existing CKD and HF.

Tracing angiotensin II's yin-yang effects on cardiovascular-renal pathophysiology

Adverse changes in cardiovascular and renal systems are major contributors to overall morbidity and mortality. Human cardiovascular and renal systems exhibit a complex network of positive and negative feedback that is reflected in the control of vascular tone via angiotensin II (Ang II) based signaling. This review will examine in some depth, the multiple components and processes that control the status and reflect the health of these various cardiovascular and renal systems, such as pathways associated to monomeric G proteins, RhoA/Rho kinase system and ERK, oxidative stress and NO balance. It will specifically emphasize the "yin-yang" nature of Ang II signaling by comparing and contrasting the effects and activity of various systems, pathways and components found in hypertension to those found in Gitelman's and Bartter's syndromes (GS/BS), two rare autosomal recessive tubulopathies characterized by electrolytic imbalance, metabolic alkalosis, sodium wasting and prominent activation of the renin-angiotensin-aldosterone system. Notwithstanding the activation of the renin-angiotensin-aldosterone system, GS/BS are normo-hypotensive and protected from cardiovascular-renal remodeling and therefore can be considered the mirror image, the opposite of hypertension.

Association between the Oxidative Balance Score and Incident Chronic Kidney Disease in Adults

Oxidative stress is a novel risk factor for chronic kidney disease (CKD). The oxidative balance score (OBS) was developed to represent the overall oxidative balance based on dietary and lifestyle pro-oxidant and antioxidant components. The aim of this study is to verify the relationship between the OBS and the incidence of CKD. Data from 5795 participants without CKD at the baseline survey of the Korean Genome and Epidemiology Study were analyzed. Participants were classified into sex-specific OBS tertiles. During the mean follow-up period of 13.6 years, 286 men and 382 women newly developed CKD. The Cox proportional hazard spline curve revealed an inverse dose-response association between the OBS and incident CKD in both men and women. Multiple Cox proportional hazard regression analysis revealed that the adjusted hazard ratios (95% confidence intervals) for sex-specific highest (T3) and middle (T2) OBS tertile groups were 0.80 (0.59-1.08) and 0.70 (0.51-0.95), respectively, in men and 0.76 (0.59-0.98) and 0.73 (0.55-0.96), respectively, in women, with the sex-specific lowest OBS tertile group (T1) as the reference. These results suggest that a healthy diet and lifestyle that increases the OBS may help prevent CKD in both men and women.

Role of inflammation, immunity, and oxidative stress in hypertension: New insights and potential therapeutic targets

Hypertension is regarded as the most prominent risk factor for cardiovascular diseases, which have become a primary cause of death, and recent research has demonstrated that chronic inflammation is involved in the pathogenesis of hypertension. Both innate and adaptive immunity are now known to promote the elevation of blood pressure by triggering vascular inflammation and microvascular remodeling. For example, as an important part of innate immune system, classically activated macrophages (M1), neutrophils, and dendritic cells contribute to hypertension by secreting inflammatory cy3tokines. In particular, interferon-gamma (IFN-γ) and interleukin-17 (IL-17) produced by activated T lymphocytes contribute to hypertension by inducing oxidative stress injury and endothelial dysfunction. However, the regulatory T cells and alternatively activated macrophages (M2) may have a protective role in hypertension. Although inflammation is related to hypertension, the exact mechanisms are complex and unclear. The present review aims to reveal the roles of inflammation, immunity, and oxidative stress in the initiation and evolution of hypertension. We envisage that the review will strengthen public understanding of the pathophysiological mechanisms of hypertension and may provide new insights and potential therapeutic strategies for hypertension.

N-Acetylcysteine: more than preventing contrast-induced nephropathy in uremic patients-focus on the antioxidant and anti-inflammatory properties

Oxidative stress (OS) has been recognized as a pathophysiologic mechanism underlying the development and progression of chronic kidney disease (CKD). OS, which results from the disturbance of balance among pro-oxidants and antioxidants favoring the pro-oxidants, is present even in early CKD and increases progressively along with deterioration of kidney function to end-stage kidney disease (ESKD). In ESKD, OS is further exacerbated mainly due to dialysis procedures per se and predisposes to increased cardiovascular morbidity and mortality. Therefore, since OS plays a pivotal role in the pathogenesis and progression of atherosclerosis in uremic patients, several strategies aiming to ameliorate OS in these patients have been proposed. Among those, N-acetylcysteine (NAC), a thiol-containing antioxidant agent, has attracted special attention due to its pleiotropic functions and beneficial effect in various OS-related entities including paracetamol overdose and prevention of contrast-induced nephropathy. In this review, we present the currently available literature on the antioxidant and anti-inflammatory properties of NAC in CKD, including hemodialysis and peritoneal dialysis.

New mechanisms involved in the development of cardiovascular disease in chronic kidney disease

Chronic kidney disease (CKD) is a pathology with a high worldwide incidence and an upward trend affecting the elderly. When CKD is very advanced, the use of renal replacement therapies is required to prolong its life (dialysis or kidney transplantation). Although dialysis improves many complications of CKD, the disease does not reverse completely. These patients present an increase in oxidative stress, chronic inflammation and the release of extracellular vesicles (EVs), which cause endothelial damage and the development of different cardiovascular diseases (CVD). CKD patients develop premature diseases associated with advanced age, such as CVD. EVs play an essential role in developing CVD in patients with CKD since their number increases in plasma and their content is modified. The EVs of patients with CKD cause endothelial dysfunction, senescence and vascular calcification. In addition, miRNAs free or transported in EVs together with other components carried in these EVs promote endothelial dysfunction, thrombotic and vascular calcification in CKD, among other effects. This review describes the classic factors and focuses on the role of new mechanisms involved in the development of CVD associated with CKD, emphasizing the role of EVs in the development of cardiovascular pathologies in the context of CKD. Moreover, the review summarized the EVs' role as diagnostic and therapeutic tools, acting on EV release or content to avoid the development of CVD in CKD patients.

Association of serum lycopene concentrations with all-cause and cardiovascular mortality among individuals with chronic kidney disease: A cohort study

Background

Lycopene is one of the hydrocarbon carotenoids which is largely studied for its strong antioxidant and anti-inflammatory properties, as well as improvement of endothelial function and anti-arteriosclerosis effects. The use of lycopene has been shown to reduce mortality in the general population. However, few studies have examined the association between serum lycopene level and all-cause and cardiovascular mortality among participants with chronic kidney disease (CKD).

Method

This study included 7,683 adults with CKD from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994) and NHANES 2001-2006. Mortality status and cause of death were ascertained by linkage to National Death Index records through 31 December 2018. Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% CIs for mortality from all-cause and cardiovascular disease (CVD).

Result

During a median follow-up time of 309 months, there were 5,226 total deaths. The median (interquartile range) serum lycopene concentration was 20.0 (12.0, 32.0) μg/dl. After fully adjusted, restricted cubic spline analyses reported that higher serum lycopene concentrations were significantly associated with decreased risk of all-cause and CVD mortality in participants with CKD (P < 0.001, P = 0.001). When extreme quartiles of serum lycopene concentrations were compared, the multivariable-adjusted HR (95% CI) was 0.778 (0.714-0.848) for all-cause mortality (P < 0.001), and 0.791 (0.692-0.905) for CVD mortality (P < 0.001). Specifically, higher serum lycopene decreased the risk of all-cause and CVD mortality at both CKD stage 1-2 and stage 3-5. Further subgroup analyses and sensitivity analyses supported the current results.

Conclusion

Higher serum lycopene was independently associated with a decreased risk of all-cause and CVD mortality in patients with CKD. These findings suggested that maintain serum lycopene concentrations could lower mortality risk in CKD patients.

Association of oxidative stress with erectile dysfunction in community-dwelling men and men on dialysis

OBJECTIVES

To investigate the association between oxidative stress and erectile dysfunction (ED) in community-dwelling men and men on dialysis.

METHODS

This cross-sectional study included 398 community-dwelling men and 42 men on dialysis. Oxidative stress was assessed using 8-hydroxy-2'-deoxyguanosine (8-OHdG). Univariable and multivariable logistic regression analyses were performed to evaluate the association between oxidative stress and ED.

RESULTS

Spearman's rank correlation test showed no significant correlation between urine 8-OHdG levels and the 5-Item International Index of Erectile Function scores in community-dwelling men (ρ = -0.005, p = 0.917) and between plasma 8-OHdG levels and the Sexual Health Inventory for Men scores in men on dialysis (ρ = 0.166, p = 0.295). In community-dwelling men, univariable and multivariable analyses revealed that urine 8-OHdG level was not significantly associated with ED (odds ratio [OR]: 1.005, 95% confidence interval [CI]: 0.884-1.144, p = 0.934; OR: 0.930, 95% CI: 0.798-1.084, p = 0.353; respectively). In men on dialysis, univariable analyses revealed that plasma 8-OHdG level was not significantly associated with severe ED (OR: 0.967, 95% CI: 0.876-1.066, p = 0.498).

CONCLUSIONS

Oxidative stress was not significantly associated with ED prevalence and severity in community-dwelling men and men on dialysis.

Exercise Training Ameliorates Renal Oxidative Stress in Rats with Chronic Renal Failure

In patients with chronic kidney disease, exercise training with moderate intensity protects renal function and improves mortality. However, the mechanisms of the renal protective effects of exercise training in chronic kidney disease have not been clarified. This study investigated the effects of exercise training on renal NADPH oxidative and xanthine oxidase, which are major sources of reactive oxygen species, in rats with chronic renal failure. Six-week-old, male Sprague–Dawley rats were divided into the sham operation, 5/6 nephrectomy (Nx)+ sedentary, and Nx+ exercise training groups. The Nx+ exercise training group underwent treadmill running. After 12 weeks, systolic blood pressure, renal function, malondialdehyde, renal NADPH oxidase, and xanthine oxidase were examined. Nx induced hypertension, proteinuria, and renal dysfunction, and exercise training attenuated these disorders. Although the plasma levels of malondialdehyde were not different among the group, urinary levels were increased by Nx and decreased by exercise training. Renal activity and expression of NADPH oxidase and xanthine oxidase were increased by Nx and decreased by exercise training. These results indicate that exercise training attenuates hypertension and renal dysfunction and ameliorates NADPH oxidase and xanthine oxidase in rats with chronic renal failure, suggesting that the reduction of reactive oxygen species generation may be involved in the renal protective effects of exercise training.

Targeted biomarkers of progression in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is an increasingly significant health issue worldwide. Early stages of CKD can be asymptomatic and disease trajectory difficult to predict. Not everyone with CKD progresses to kidney failure, where kidney replacement therapy is the only life-sustaining therapy. Predicting which patients will progress to kidney failure would allow better use of targeted treatments and more effective allocation of health resources. Current diagnostic tests to identify patients with progressive disease perform poorly but there is a suite of new and emerging predictive biomarkers with great clinical promise.

METHODS

This narrative review describes new and emerging biomarkers of pathophysiologic processes of CKD development and progression, accessible in blood or urine liquid biopsies. Biomarkers were selected based on their reported pathobiological functions in kidney injury, inflammation, oxidative stress, repair and fibrosis. Biomarker function and evidence of involvement in CKD development and progression are reported.

CONCLUSION

Many biomarkers reviewed here have received little attention to date, perhaps because of conflicting conclusions of their utility in CKD. The functional roles of the selected biomarkers in the underlying pathobiology of progression of CKD are a powerful rationale for advancing and validating these molecules as prognosticators and predictors of CKD trajectory.