Oxidative Stress in the Pathogenesis and Evolution of Chronic Kidney Disease: Untangling Ariadne's Thread

Inflammatory indexes and anemia in chronic kidney disease: correlation and survival analysis of the National Health and Nutrition Examination Survey 2005-2018

BACKGROUND

There is currently no research on the correlation between novel inflammatory indexes systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and the risk of anemia in chronic kidney disease (CKD) population, as well as survival analysis in CKD with anemia.

METHODS

This investigation encompassed 4444 adult subjects out of the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2018. The study utilized multi-variable logistic regression to assess the relationship between SII, NLR, PLR, and anemia risk occurrence in CKD population. Survival differences in CKD patients with anemia, based on varying levels of SII, NLR, and PLR were evaluated employing Kaplan-Meier and Cox proportional hazards models.

RESULTS

The adjusted logistic regression model demonstrates that SII, NLR, and PLR are associated with the risk of anemia occurrence in CKD population. Kaplan-Meier's analysis reveals significant differences in survival rates among CKD patients with anemia stratified by NLR levels. The adjusted Cox proportional hazards model shows that the higher NLR group has a 30% elevated risk of all-cause mortality contrasted with lower group (hazard ratio, HR: 1.30, confidence interval (CI) [1.01, 1.66], p value <.04). Restricted cubic spline (RCS) demonstrates no nonlinear relationship between NLR and all-cause mortality. Lastly, sub-cohort analysis indicates that in populations with diabetes, hypertension, and hyperuricemia, NLR levels have a greater impact on all-cause mortality.

CONCLUSIONS

Controlling inflammation may reduce the occurrence of anemia in CKD populations, with NLR serving to be a potential prognostic indicator for survival results within CKD patients suffering from co-morbid anemia.

Advances in Traditional Chinese Medicine research in diabetic kidney disease treatment

CONTEXT

Diabetic kidney disease (DKD) is a prominent complication arising from diabetic microangiopathy, and its prevalence and renal impact have placed it as the primary cause of end-stage renal disease. Traditional Chinese Medicine (TCM) has the distinct advantage of multifaceted and multilevel therapeutic attributes that show efficacy in improving clinical symptoms, reducing proteinuria, protecting renal function, and slowing DKD progression. Over recent decades, extensive research has explored the mechanisms of TCM for preventing and managing DKD, with substantial studies that endorse the therapeutic benefits of TCM compounds and single agents in the medical intervention of DKD.

OBJECTIVE

This review lays the foundation for future evidence-based research efforts and provide a reference point for DKD investigation.

METHODS

The relevant literature published in Chinese and English up to 30 June 2023, was sourced from PubMed, Cochrane Library, VIP Database for Chinese Technical Periodicals (VIP), Wanfang Data, CNKI, and China Biology Medicine disc (CBM). The process involved examining and summarizing research on TCM laboratory tests and clinical randomized controlled trials for DKD treatment.

RESULTS AND CONCLUSIONS

The TCM intervention has shown the potential to inhibit the expression of inflammatory cytokines and various growth factors, lower blood glucose levels, and significantly affect insulin resistance, lipid metabolism, and improved renal function. Furthermore, the efficacy of TCM can be optimized by tailoring personalized treatment regimens based on the unique profiles of individual patients. We anticipate further rigorous and comprehensive clinical and foundational investigations into the mechanisms underlying the role of TCM in treating DKD.

Evaluating the lipid accumulation product index as a predictor for kidney stone prevalence: insights from NHANES 2007-2018

PURPOSE

This study aimed to explore the relationship between the lipid accumulation product (LAP) index and kidney stone prevalence, utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2018.

METHODS

An observational study was executed employing the NHANES dataset from 2007 to 2018. Analytical methods encompassed multivariate logistic regression, restricted cubic splines (RCS), subgroup analysis, and interaction tests. Predictions were made using the receiver operating characteristic (ROC) curve and the area under the curve (AUC) values.

RESULTS

The analysis included 9744 adults aged 20 years and older. Multivariate logistic regression identified a significant positive association between log2-transformed LAP (treated as a continuous variable) and kidney stone risk across all models, with odds ratios (ORs) exceeding 1 and p values less than 0.001. Categorically, ORs escalated with increasing LAP levels, indicating a dose-response relationship. The RCS analysis confirmed a linear positive correlation between log2-transformed LAP and kidney stone risk. Subgroup analyses revealed that the log2-transformed LAP-kidney stones relationship was consistent, unaffected by stratification across the examined variables. In addition, LAP index (AUC = 0.600) proved to be a more effective predictor of kidney stones compared to body mass index (AUC = 0.584).

CONCLUSION

Elevated LAP levels are positively correlated with a higher incidence of kidney stones, signifying its potential as a risk marker for this condition. Future research should investigate the mechanisms underlying this relationship. LAP can be used as a new anthropometric index to predict kidney stones, and its predictive ability is stronger than body mass index.

Association between preterm delivery and the risk of maternal renal disease: A systematic review and meta‑analysis

The present systematic review and meta-analysis aimed to generate high-quality evidence on the association between preterm delivery (PTD) and subsequent risk of renal disease in the mother. A literature search was conducted on PubMed, Embase, CENTRAL and Scopus until the 15th of May 2023 for studies reporting an adjusted association between PTD and the risk of maternal renal disease. A total of seven studies were eligible. The pooled analysis found that women with PTD had a statistically significant increased risk of chronic kidney disease in the long term [hazard ratio (HR): 1.82 95% confidence interval (CI): 1.38, 2.40; I2=85%]. Similarly, the meta-analysis also found a statistically significant increased risk of end-stage renal disease (ESRD) amongst women with PTD as compared with those without PTD (HR: 2.22 95% CI: 1.95, 2.53; I2=0%). Overall, the pooled analysis showed a significantly higher incidence of renal disorders with PTD (HR: 1.98; 95% CI: 1.57, 2.50; I2=88%). The results were unchanged on sensitivity analysis. Women with PTD could be at increased risk of future chronic kidney disease and ESRD. The small number of studies and retrospective nature of data are important limitations. Further studies are needed to supplement the available evidence.

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.

CYP2E1 mediated advanced oxidation protein products exacerbate acetaminophen induced drug-derived liver injury in vitro and in vivo

Drug-induced liver injury (DILI) is prevalent in the treatment of chronic kidney disease (CKD). Advanced oxidation protein products (AOPPs) are markers of CKD progression and participate in the occurrence and development of liver diseases. However, the mechanisms underlying the regulation of DILI in CKD have not been established. Herein, we demonstrate the involvement of Cytochrome p450 2E1 (CYP2E1) in DILI induced by AOPPs is exacerbated by exposure to acetaminophen (APAP). We used a adenine-induced CKD model, a model of DILI induced by APAP, and the AOPPs model was generated by intraperitoneal injection. The decline in renal function was associated with a significantly increased concentration of Scr, BUN and AOPPs, and renal tissue fibrosis. The ALT, AST, and AOPPs levels and liver tissue necrosis increased significantly in CKD model group compared with the sodium carboxymethyl cellulose (CMCNa) group. In the AOPPs model, compared to the PBS controls, ALT, AST, and AOPP levels, and liver tissue necrosis increased significantly. In HepG2 or L0-2 cell lines, cell survival was significantly reduced in the AOPP + APAP treatment and CYP2E1 protein expression was increased. FPS-ZM1 or NAC attenuated the hepatocyte toxicity induced by AOPP + APAP and suppression of CYP2E1 expression. AOPPs exacerbated APAP-induced DILI through CYP2E1 signaling pathways. Protein uremic toxins, such as AOPPs, can modify drug toxicity in patients with CKD. This study provides new a rationale to reduce the generation of DILIs in clinical treatment in patients with CKD. AOPPs targeting may present a novel approach to reduce the occurrence of DILI.

Podocyte Death in Diabetic Kidney Disease: Potential Molecular Mechanisms and Therapeutic Targets

Cell deaths maintain the normal function of tissues and organs. In pathological conditions, the abnormal activation or disruption of cell death often leads to pathophysiological effects. Diabetic kidney disease (DKD), a significant microvascular complication of diabetes, is linked to high mortality and morbidity rates, imposing a substantial burden on global healthcare systems and economies. Loss and detachment of podocytes are key pathological changes in the progression of DKD. This review explores the potential mechanisms of apoptosis, necrosis, autophagy, pyroptosis, ferroptosis, cuproptosis, and podoptosis in podocytes, focusing on how different cell death modes contribute to the progression of DKD. It recognizes the limitations of current research and presents the latest basic and clinical research studies targeting podocyte death pathways in DKD. Lastly, it focuses on the future of targeting podocyte cell death to treat DKD, with the intention of inspiring further research and the development of therapeutic strategies.

Oxidative Stress and Erectile Dysfunction: Pathophysiology, Impacts, and Potential Treatments

Erectile dysfunction (ED) is a prevalent condition affecting men's sexual health, with oxidative stress (OS) having recently been identified as a significant contributing causative factor. This narrative review aims to elucidate the role of OS in the pathophysiology of ED, focusing on impact, mechanisms, and potential therapeutic interventions. Key findings indicate that OS disrupts endothelial function and nitric oxide (NO) signaling, crucial for erectile function. Various sources of reactive oxygen species (ROS) and their detrimental effects on penile tissue are discussed, including aging, diabetes mellitus, hypertension, hyperlipidemia, smoking, obesity, alcohol consumption, psychological stress, hyperhomocysteinemia, chronic kidney disease, and sickle cell disease. Major sources of ROS, such as NADPH oxidase, xanthine oxidase, uncoupled endothelial NO synthase (eNOS), and mitochondrial electron transport, are identified. NO is scavenged by these ROS, leading to endothelial dysfunction characterized by reduced NO availability, impaired vasodilation, increased vascular tone, and inflammation. This ultimately results in ED due to decreased blood flow to penile tissue and the inability to achieve or maintain an erection. Furthermore, ROS impact the transmission of nitrergic neurotransmitters by causing the death of nitrergic neurons and reducing the signaling of neuronal NO synthase (nNOS), exacerbating ED. Therapeutic approaches targeting OS, including antioxidants and lifestyle modifications, show promise in ameliorating ED symptoms. The review underscores the need for further research to develop effective treatments, emphasizing the interplay between OS and vascular health in ED. Integrating pharmacological and non-pharmacological strategies could enhance clinical outcomes for ED patients, advocating for OS management in ED treatment protocols to improve patient quality of life.

Effects of dietary compounds on nuclear factor erythroid 2-related factor 2 (Nrf2) modulation in chronic kidney disease: a systematic review of clinical trials

Nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important transcription factor that activates antioxidant genes and increases detoxifying enzymes. Studies have shown that dietary compounds can activate the Nrf2 expression and improve the antioxidant response in patients with exacerbated oxidative stress, such as chronic kidney disease (CKD). We aimed to evaluate the efficacy of nutritional interventions on Nrf2 expression and phase II antioxidant enzymes in clinical trials in CKD. We searched PubMed, Lilacs, Embase, Scopus, and Cochrane Library databases of published clinical trials and the Cochrane tool was used for the quality assessment of the studies included. We reported this review according to the PRISMA and it was registered in PROSPERO (42023389619). Thirty-nine studies were included in this review; nine evaluated the Nrf2 expression and three showed an increase in its expression. Twenty-three studies found an increase in the antioxidant enzyme levels, including superoxide dismutase, catalase, and glutathione peroxidase. Moreover, a high risk of bias was found in most of the studies and high heterogeneity in the designs, type, and duration of supplementation administered. These results suggest that dietary supplementations have a promising effect on the antioxidant enzyme response, however, it is recommended that further studies should be carried out.

Increased Prorenin Expression in the Kidneys May Be Involved in the Abnormal Renal Function Caused by Prolonged Environmental Exposure to Microcystin-LR

Toxic algae in eutrophic lakes produce cyanotoxic microcystins. Prior research on the effect of microcystin-LR in the kidney utilized intraperitoneal injections, which did not reflect natural exposure. Oral microcystin-LR research has focused on renal function and histopathology without examining the molecular mechanisms. The present study aimed to evaluate the mechanism of microcystin-LR in the kidneys via oral administration in WKAH/HkmSlc rats over 7 weeks, alongside stimulation of the proximal tubular cells. Although there were no differences in the concentrations of plasma albumin, blood urea nitrogen, and creatinine, which are parameters of renal function, between the control and microcystin-LR-administrated rats, prorenin expression was significantly increased in the renal cortex of the rats administered microcystin-LR and the microcystin-LR-treated proximal tubular cells. The expression levels of (pro)renin receptor (PRR), transforming growth factor-β1 (TGFβ1), and α-smooth muscle actin (α-SMA) in the renal cortex did not differ significantly between the control and microcystin-LR-administered rats. However, the expression levels of prorenin were significantly positively correlated with those of PRR, TGFβ1, and α-SMA in the renal cortex of rats administered microcystin-LR. Additionally, a significant positive correlation was observed between the expression levels of TGFβ1 and α-SMA. Collectively, increased prorenin expression caused by the long-term consumption of microcystin-LR may initiate a process that influences renal fibrosis and abnormal renal function by regulating the expression levels of PRR, TGFβ1, and α-SMA.

Dose and Time Effects of Renin-Angiotensin Inhibitors on Patients With Advanced Stages 4 to 5 of Diabetic Kidney Disease

Context

Limited evidence exists regarding the cumulative dosing and duration impact of renin-angiotensin system inhibitors (RASis) on cardiorenal and mortality outcomes in patients with advanced stages (predominantly in stage 5 and a minority in stage 4) of diabetic kidney disease (DKD).

Objective

To retrospectively investigate whether there are dose- and time-dependent relationships between RASis and cardiorenal and mortality outcomes in this population.

Methods

Using Taiwan's national health insurance data in 2000-2017, we analyzed 2196 RASi users and 2196 propensity-matched nonusers among 8738 patients living with diabetes and newly diagnosed with advanced chronic kidney disease (23% stage 4, 77% stage 5). Cox proportional hazards regression models were used to estimate adjusted hazard ratios (aHRs) and 95% CI.

Results

RASi use was significantly associated with reduced risks of all-cause mortality (aHR, 0.53; 95% CI 0.47-0.60) and cardiovascular mortality (0.68; 0.56-0.83) with the degree of benefit depending on therapeutic dosage and duration, despite a nonsignificant increase in acute kidney injury risk (1.16; 0.98-1.38) and a significant increase in hyperkalemia risk (1.45; 1.19-1.77). Significant differences in proteinuria risk (1.32; 1.21-1.43) were observed, while there were no significant differences in end-stage renal disease risk (1.01; 0.88-1.15) and no dose- or time-response relationships for either end-stage renal disease or proteinuria risks. Sensitivity analyses confirmed cardiovascular and survival benefits, even in patients with stage 5 DKD.

Conclusion

This real-world study suggests that RASi use in advanced stages 4 to 5 DKD may provide dose- and time-dependent cardioprotection and improved survival, without excess renal harms.

The Complex Immunological Alterations in Patients with Type 2 Diabetes Mellitus on Hemodialysis

It is widely known that diabetes mellitus negatively impacts both the innate immunity (the inflammatory response) and the acquired immunity (the humoral and cellular immune responses). Many patients with diabetes go on to develop chronic kidney disease, which will necessitate hemodialysis. In turn, long-term chronic hemodialysis generates an additional chronic inflammatory response and impairs acquired immunity. The purpose of this paper is to outline and compare the mechanisms that are the basis of the constant aggression towards self-components that affects patients with diabetes on hemodialysis, in order to find possible new therapeutic ways to improve the functionality of the immune system. Our study will take a detailed look at the mechanisms of endothelial alteration in diabetes and hemodialysis, at the mechanisms of inflammatory generation and signaling at different levels and also at the mechanisms of inflammation-induced insulin resistance. It will also discuss the alterations in leukocyte chemotaxis, antigen recognition and the dysfunctionalities in neutrophils and macrophages. Regarding acquired immunity, we will outline the behavioral alterations of T and B lymphocytes induced by diabetes mellitus and chronic hemodialysis.

Advanced glycosylation end products promote the progression of CKD-MBD in rats, and its natural inhibitor, quercetin, mitigates disease progression

Chronic kidney disease-mineral and bone metabolism disorder (CKD-MBD) is a common chronic kidney disease (CKD)-associated complication that increases the risk of metabolic bone diseases, fractures, osteoblastic trans-differentiation of vascular smooth muscle cells, and cardiovascular events. SD rats were randomised into five groups with six rats per group: sham, CKD, CKD + advanced glycosylation end products (AGEs), CKD + Quercetin, and CKD + AGEs + Quercetin. The protective effects of AGEs and quercetin on SD rats were assessed by renal function, renal pathology, bone metabolism, osteoblastic trans-differentiation of vascular smooth muscle cells, and the receptor for AGE (RAGE) expression. Compared with the control group, rats in the CKD and CKD + AGEs groups had significantly lower body weight, higher serum AGEs levels, impaired renal function, increased levels of oxidative stress in the kidney and bone marrow tissues, lower femoral bone mineral density (BMD), callus mineralised volume fraction (mineralised bone volume/total volume), abnormal serum bone metabolism levels, and increased renal tissue, bone tissue, and abdominal aorta RAGE expression levels, and the RAGE downstream NF-κB signalling pathway was upregulated. Quercetin significantly improved renal dysfunction, attenuated serum AGE levels, reduced oxidative stress levels in the kidney and bone marrow tissues, and downregulated RAGE expression in the kidney, bone, and abdominal aorta and the RAGE downstream NF-κB signalling pathway in rats with CKD. AGEs are involved in the pathogenesis of CKD-MBD by promoting osteoblastic trans-differentiation of vascular smooth muscle cells and abnormal bone metabolism. Quercetin plays a role in the prevention and treatment of CKD-MBD by reducing the production of AGEs.

Strategies to address diabetic kidney disease burden in Mexico: a narrative review by the Mexican College of Nephrologists

Chronic kidney disease (CKD) is a growing global public health challenge worldwide. In Mexico, CKD prevalence is alarmingly high and remains a leading cause of morbidity and mortality. Diabetic kidney disease (DKD), a severe complication of diabetes, is a leading determinant of CKD. The escalating diabetes prevalence and the complex regional landscape in Mexico underscore the pressing need for tailored strategies to reduce the burden of CKD. This narrative review, endorsed by the Mexican College of Nephrologists, aims to provide a brief overview and specific strategies for healthcare providers regarding preventing, screening, and treating CKD in patients living with diabetes in all care settings. The key topics covered in this review include the main cardiometabolic contributors of DKD (overweight/obesity, hyperglycemia, arterial hypertension, and dyslipidemia), the identification of kidney-related damage markers, and the benefit of novel pharmacological approaches based on Sodium-Glucose Co-Transporter-2 Inhibitors (SGLT2i) and Glucagon-Like Peptide-1 Receptor Agonists (GLP-1 RA). We also address the potential use of novel therapies based on Mineralocorticoid Receptor Antagonists (MRAs) and their future implications. Emphasizing the importance of multidisciplinary treatment, this narrative review aims to promote strategies that may be useful to alleviate the burden of DKD and its associated complications. It underscores the critical role of healthcare providers and advocates for collaborative efforts to enhance the quality of life for millions of patients affected by DKD.

Pediatric nephrotic syndrome: The interplay of oxidative stress and inflammation

Background

The pathophysiological mechanisms crucial in the development of nephrotic syndrome (NS) in the pediatric population are still not fully understood. This study aimed to investigate the relationship between hypertension, oxidative stress, and inflammation in pediatric patients during the acute phase of the disease.

Methods

The study included 33 children, aged 2 to 9 years, with nephrotic syndrome. Blood samples were collected during the acute phase and remission. Parameters of oxidative status were determined, including total oxidative status (TOS), advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB), sulfhydryl groups (-SH), paraoxonase 1 (PON1), and total antioxidant status (TAS) in serum, measured spectrophotometrically. Inflam - matory parameters such as pentraxin 3 (PTX3), leptin, program med cell death ligand 1 (PD-L1), and E-cadherin were determined using enzyme-linked immunosorbent assay (ELISA).

Results

Patients with nephrotic syndrome and hypertension had significantly higher levels of advanced oxidation protein products and total antioxidant status (p=0.029 and p=0.003, respectively). During the acute phase of the disease, lower activity of sulfhydryl groups and paraoxonase 1 was observed compared to remission (p<0.001, for both). Pentraxin 3 levels were higher, while leptin levels were lower during the acute phase (p<0.001, for both). Pentraxin 3 correlated with advanced oxidation protein products and total antioxidant status during the acute phase but not in remission (rs=0.42, p=0.027 and rs=0.43, p=0.025, respectively). A negative correlation between Advanced oxidation protein products and leptin was observed during the acute phase, which disappeared in remission (rs=-0.42, p=0.028).

Conclusions

Results of this study show that hypertension influences oxidative stress markers, and decreased antioxidant capacity may contribute to nephrotic syndrome development. Pentraxin 3 appears as a potential disease activity marker, indicating a dynamic connection between inflammation and oxidative stress. Leptin may also play a role in oxidative stress in nephrotic syndrome.

Exploring Therapeutic Potential of Catalase: Strategies in Disease Prevention and Management

The antioxidant defense mechanisms play a critical role in mitigating the deleterious effects of reactive oxygen species (ROS). Catalase stands out as a paramount enzymatic antioxidant. It efficiently catalyzes the decomposition of hydrogen peroxide (H2O2) into water and oxygen, a potentially harmful byproduct of cellular metabolism. This reaction detoxifies H2O2 and prevents oxidative damage. Catalase has been extensively studied as a therapeutic antioxidant. Its applications range from direct supplementation in conditions characterized by oxidative stress to gene therapy approaches to enhance endogenous catalase activity. The enzyme's stability, bioavailability, and the specificity of its delivery to target tissues are significant hurdles. Furthermore, studies employing conventional catalase formulations often face issues related to enzyme purity, activity, and longevity in the biological milieu. Addressing these challenges necessitates rigorous scientific inquiry and well-designed clinical trials. Such trials must be underpinned by sound experimental designs, incorporating advanced catalase formulations or novel delivery systems that can overcome existing limitations. Enhancing catalase's stability, specificity, and longevity in vivo could unlock its full therapeutic potential. It is necessary to understand the role of catalase in disease-specific contexts, paving the way for precision antioxidant therapy that could significantly impact the treatment of diseases associated with oxidative stress.

Associations between oxidative balance score and chronic kidney disease events in US adults: a population-based study

Oxidative Balance Scores (OBS) are utilized to assess an individual's antioxidant status, encompassing both dietary and lifestyle factors that contribute to oxidative balance. This study investigates the relationship between OBS and chronic kidney disease (CKD) prevalence among U.S. adults, utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. The study involved a cross-sectional analysis of 13,373 individuals from NHANES, focusing on adults aged 20 years or older. OBS was calculated using 20 components, including dietary and lifestyle factors. CKD was identified based on albumin-to-creatinine ratio and estimated glomerular filtration rate, with patients stratified into mild, moderate, and high-risk groups. Statistical analysis included logistic regression models and restricted cubic splines to explore the OBS-CKD relationship. Our findings indicate a statistically significant negative correlation between OBS and CKD prevalence, particularly in mild and moderate-risk groups. Higher OBS quartiles were associated with a decreased likelihood of CKD (OR 0.70; 95% CI 0.53-0.92; P = 0.013). Restricted cubic splines indicated a non-linear, inverse association between OBS and CKD odds for the overall population (P for nonlinearity = 0.017). For mild and moderate CKD risk groups, the relationships were less pronounced (P for nonlinearity = 0.053 and 0.184, respectively), suggesting variability in the OBS-CKD link across different risk levels. The study highlights the potential of elevated OBS as a primary prevention measure for CKD, particularly in individuals with mild to moderate risk. These findings underscore the importance of antioxidant status in CKD risk management and encourage further research into the role of dietary and lifestyle factors in CKD prevention.

Donor-Dependent Variations in Systemic Oxidative Stress and Their Association with One-Year Graft Outcomes in Kidney Transplantation

INTRODUCTION

Oxidative stress has been implicated in complications after kidney transplantation (KT), including delayed graft function (DGF) and rejection. However, its role in long-term posttransplant outcomes remains unclear.

METHODS

We investigated oxidative damage and antioxidant defense dynamics, and their impact on the graft outcomes, in 41 KT recipients categorized by type of donation over 12 months. Oxidative status was determined using OxyScore and AntioxyScore indexes, which comprise several circulating biomarkers of oxidative damage and antioxidant defense. Donor types included donation after brain death (DBD [61.0%]), donation after circulatory death (DCD [26.8%]), and living donation (LD [12.1%]).

RESULTS

There was an overall increase in oxidative damage early after transplantation, which was significantly higher in DCD as compared to DBD and LD recipients. The multivariate adjustment confirmed the independent association of OxyScore and type of deceased donation with DGF, donor kidney function, and induction therapy with antithymocyte globulin. There were no differences in terms of antioxidant defense. Lower oxidative damage at day 7 predicted better graft function at 1-year posttransplant only in DBD recipients.

CONCLUSION

DCD induced greater short-term oxidative damage after KT, whereas the early levels of oxidative damage were predictive of the graft function 1 year after KT among DBD recipients.

The impact of hypoxia preconditioning on mesenchymal stem cells performance in hypertensive kidney disease

BACKGROUND

Autologous mesenchymal stem cells (MSCs) have emerged as a therapeutic option for many diseases. Hypertensive kidney disease (HKD) might impair MSCs' reparative ability by altering the biomolecular properties, but the characteristics of this impairment are unclear. In our previous pre-clinical studies, we found hypoxic preconditioning (HPC) enhanced angiogenesis and suppressed senescence gene expression. Thus, we hypothesize that HPC would improve human MSCs by enhancing their functionality and angiogenesis, creating an anti-inflammatory and anti-senescence environment.

METHODS

MSC samples (n = 12 each) were collected from the abdominal fat of healthy kidney donors (HC), hypertensive patients (HTN), and patients with hypertensive kidney disease (HKD). MSCs were harvested and cultured in Normoxic (20% O2) or Hypoxic (1% O2) conditions. MSC functionality was measured by proliferation assays and cytokine released in conditioned media. Senescence was evaluated by senescence-associated beta-galactosidase (SA-beta-gal) activity. Additionally, transcriptome analysis using RNA-sequencing and quantitative PCR (qPCR) were performed.

RESULTS

At baseline, normoxic HTN-MSCs had higher proliferation capacity compared to HC. However, HPC augmented proliferation in HC. HPC did not affect the release of pro-angiogenic protein VEGF, but increased EGF in HC-MSC, and decreased HGF in HC and HKD MSCs. Under HPC, SA-β-gal activity tended to decrease, particularly in HC group. HPC upregulated mostly the pro-angiogenic and inflammatory genes in HC and HKD and a few senescence genes in HKD.

CONCLUSIONS

HPC has a more favorable functional effect on HC- than on HKD-MSC, reflected in increased proliferation and EGF release, and modest decrease in senescence, whereas it has little effect on HTN or HKD MSCs.

Association between chronic renal disease and psoriasis risk in diabetes patients: A Korean population-based study

Background Several studies have reported that psoriasis has a positive correlation with type 2 diabetes mellitus (DM). Understanding the risk of psoriasis in diabetic patients is significant because it allows for early intervention and potential insights into the common pathways between the two conditions. Objectives We analysed the risk of psoriasis according to the estimated glomerular filtration rate (eGFR) and proteinuria level in DM patients using Korean population-based data. Methods This study was a retrospective cohort study using data collected from the country in the form of exploratory data analysis. A total of 927,234 participants diagnosed with DM were enrolled. Patients under the age of 20 with existing psoriasis or psoriasis developed within 1 year and missing data were excluded. The development of psoriasis was the primary outcome within a follow-up period of 7.83 ± 1.68 years. Results Of the 840,395 final participants, 28,010 (3.33%) patients developed psoriasis. In multivariate-adjusted Cox proportional hazards regression models, the DM patients with eGFR < 30 had a higher risk of psoriasis after adjustment (eGFR 60-90, hazard ratio [HR] 1 (Ref.); eGFR < 30, HR 1.173, 95% CI 1.089-1.264). In addition, there was an increased psoriatic risk of patients with DM and proteinuria after adjustment (negative, HR 1 (Ref.); 2+, HR 1.164, 95% CI 1.080-1.254; 3+, HR 1.433, 95% CI 1.273-1.613; 4+, HR 1.508, 95% CI 1.177-1.931). Limitations The severity of psoriasis was not measured since the occurrence of psoriasis was the outcome. Details of oral hypoglycaemic agents such as type and dose were not investigated. Conclusion This study showed that a decrease in eGFR and aggravation of proteinuria increase the risk of psoriasis in diabetic patients. Therefore, by using eGFR and proteinuria as predictive risk factors of psoriasis in DM patients, early and proactive treatment may play a vital role in managing diabetic patients.

Therapeutic potentials of glucose-dependent insulinotropic polypeptide (GIP) in T2DM: Past, present, and future

Type 2 diabetes mellitus (T2DM) is a worldwide health problem that has raised major concerns to the public health community. This chronic condition typically results from the cell's inability to respond to normal insulin levels. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the primary incretin hormones secreted from the intestinal tract. While clinical research has extensively explored the therapeutic potential of GLP-1R in addressing various T2DM-related abnormalities, the possibility of GIPR playing an important role in T2DM treatment is still under investigation. Evidence suggests that GIP is involved in the pathophysiology of T2DM. This chapter focuses on examining the role of GIP as a therapeutic molecule in combating T2DM, comparing the past, present, and future scenarios. Our goal is to delve into how GIP may impact pancreatic β-cell function, adipose tissue uptake, and lipid metabolism. Furthermore, we will elucidate the mechanistic functions of GIP and its receptors in relation to other clinical conditions like cardiovascular diseases, non-alcoholic fatty liver diseases, neurodegenerative diseases, and renal disorders. Additionally, this chapter will shed light on the latest advancements in pharmacological management for T2DM, highlighting potential structural modifications of GIP and the repurposing of drugs, while also addressing the challenges involved in bringing GIP-based treatments into clinical practice.

Association between exposure to metalworking fluid aerosols, occupational noise and chronic kidney disease: a cross-sectional study in China

BACKGROUND

Chronic kidney disease (CKD) carries a high public health burden yet little is known about the relationship between metalworking fluid (MWF) aerosols, occupational noise and CKD. We aimed to explore the relationship between occupational MWF aerosols, occupational noise and CKD.

METHODS

A total of 2,738 machinists were sampled from three machining companies in Wuxi, China, in 2022. We used the National Institute for Occupational Safety and Health (NIOSH) method 5524 to collect individual samples for MWF aerosols exposure, and the Chinese national standard (GBZ/T 189.8-2007) method to test individual occupational noise exposure. The diagnostic criteria for CKD were urinary albumin/creatinine ratio (UACR) of ≥ 30 mg/g and reduced renal function (eGFR < 60 mL.min- 1. 1.73 m- 2) lasting longer than 3 months. Smooth curve fitting was conducted to analyze the associations of MWF aerosols and occupational noise with CKD. A segmented regression model was used to analyze the threshold effects.

RESULTS

Workers exposed to MWF aerosols (odds ratio [OR] = 2.03, 95% confidence interval [CI]: 1.21-3.41) and occupational noise (OR = 1.77, 95%CI: 1.06-2.96) had higher prevalence of CKD than nonexposed workers. A nonlinear and positive association was found between increasing MWF aerosols and occupational noise dose and the risk of CKD. When daily cumulative exposure dose of MWF aerosols exceeded 8.03 mg/m3, the OR was 1.24 (95%CI: 1.03-1.58), and when occupational noise exceeded 87.22 dB(A), the OR was 1.16 (95%CI: 1.04-1.20). In the interactive analysis between MWF aerosols and occupational noise, the workers exposed to both MWF aerosols (cumulative exposure ≥ 8.03 mg/m3-day) and occupational noise (LEX,8 h ≥ 87.22 dB(A)) had an increased prevalence of CKD (OR = 2.71, 95%CI: 1.48-4.96). MWF aerosols and occupational noise had a positive interaction in prevalence of CKD.

CONCLUSIONS

Occupational MWF aerosols and noise were positively and nonlinearly associated with CKD, and cumulative MWF aerosols and noise exposure showed a positive interaction with CKD. These findings emphasize the importance of assessing kidney function of workers exposed to MWF aerosols and occupational noise. Prospective and longitudinal cohort studies are necessary to elucidate the causality of these associations.

Comparison between intermittent claudication versus chronic limb-threatening ischemia in peripheral arterial disease: a retrospective multicenter cohort study

Purpose

The anatomical distribution, characteristics of lesions, and treatment modalities for peripheral artery disease (PAD) are diverse. Endovascular intervention is popular for symptomatic PAD, for both intermittent claudication (IC) and chronic limb-threatening ischemia (CLTI). We aimed to investigate the endovascular devices used by comparing patients with PAD referred for endovascular revascularization with IC and CLTI.

Methods

We identified 736 patients with PAD enrolled in the multicenter PAD registry in South Korea from 2019 to 2022. Of these patients, 636 received endovascular treatment at the time of this study. After excluding missing data, we analyzed 506 patients with IC or CLTI. Patients' characteristics, target lesions, and endovascular device data such as type, length, balloon diameter, and stent, were examined. Procedure outcomes of the aortoiliac, femoropopliteal, and below-the-knee lesions were analyzed.

Results

Patients with CLTI were more likely to have diabetes mellitus, below-the-knee interventions, and multilevel PAD than the IC group. Patients with IC had more aortoiliac artery lesions and underwent atherectomies than the CLTI group (63.3% and 61.1% vs. 39.7% and 40.6%, respectively; P < 0.001). In patients with femoropopliteal lesions, those with CLTI were more revascularized with stents than the patients with IC, without significant differences (35.3% vs. 29.1%, P = 0.161). Compared to the IC group, the CLTI patients showed significantly worse rates of primary patency, amputation, and mortality (P = 0.029, P < 0.001, and P < 0.001, respectively).

Conclusion

Among Korean patients with PAD, there is a significant difference in baseline and lesion characteristics, endovascular strategies, and short-term follow-up outcomes among those with IC and CLTI.

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.

Design and discovery of a highly potent ultralong-acting GLP-1 and glucagon co-agonist for attenuating renal fibrosis

The role of co-agonists of glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR) in chronic kidney disease (CKD) remains unclear. Herein we found that GLP-1R and GCGR expression levels were lower in the kidneys of mice with CKD compared to healthy mice and were correlated with disease severity. Interestingly, GLP-1R or GCGR knockdown aggravated the progression of kidney injury in both diabetic db/db mice and non-diabetic mice undergoing unilateral ureteral obstruction (UUO). Based on the importance of GLP-1R and GCGR in CKD, we reported a novel monomeric peptide, 1907-B, with dual-agonism on both GLP-1R and GCGR. The data confirmed that 1907-B had a longer half-life than long-acting semaglutide in rats or cynomolgus monkeys (∼2-3 fold) and exhibited better therapeutic contribution to CKD than best-in-class monoagonists, semaglutide, or glucagon, in db/db mice and UUO mice. Various lock-of-function models, including selective pharmacological activation and genetic knockdown, confirmed that 1907-B's effects on ameliorating diabetic nephropathy in db/db mice, as well as inhibiting kidney fibrosis in UUO mice, were mediated through GLP-1 and glucagon signaling. These findings highlight that 1907-B, a novel GLP-1R and GCGR co-agonist, exerts multifactorial improvement in kidney injuries and is an effective and promising therapeutic option for CKD treatment.

Long-term impacts of endocrine-disrupting chemicals exposure on kidney function: A community-based cohort study

This study explores the extended renal effects of endocrine-disrupting chemicals (EDCs) exposure, a linkage already established with adverse health outcomes, notably chronic kidney disease. To delve deeper, the Chang Gung Community Research Center conducted a longitudinal study with 887 participants. Among them, 120 individuals were scrutinized based on EDC scores, analyzing 17 urinary EDCs and renal function. Findings revealed elevated mono-(2-ethylhexyl) phthalate (MEHP) and bisphenol A levels in higher EDC exposure cases. MEHP notably correlated with increased urinary albumin-to-creatinine ratio (UACR), predicting a > 15% decline in estimated glomerular filtration rate. Higher MEHP levels also hinted at declining renal function. UACR escalation linked significantly with specific EDCs: MEHP, methylparaben, nonylphenol, and 4-tert-octylphenol. This research underscores enduring renal hazards tied to environmental EDC exposure, particularly MEHP, emphasizing the urgent call for robust preventive public health strategies.

Associations Between Individual and Combined Metal Exposures in Whole Blood and Kidney Function in U.S. Adults Aged 40 Years and Older

The effects of metal exposure on kidney function have been reported in previous literature. There is limited and inconsistent information on the associations between individual and combined exposures to metals and kidney function among the middle-aged and older population. The aim of this study was to clarify the associations of exposure to individual metals with kidney function while accounting for potential coexposure to metal mixtures and to evaluate the joint and interactive associations of blood metals with kidney function. A total of 1669 adults aged 40 years and older were enrolled in the present cross-sectional study using the 2015-2016 National Health and Nutrition Examination Survey (NHANES). Single-metal and multimetal multivariable logistic regression models, quantile G-computation, and Bayesian kernel machine regression models (BKMR) were fitted to explore the individual and joint associations of whole blood metals [lead (Pb), cadmium (Cd), mercury (Hg), cobalt (Co), manganese (Mn), and selenium (Se)] with the odds of decreased estimated glomerular filtration rate (eGFR) and albuminuria. A decreased eGFR was defined as an eGFR ≤ 60 mL/min per 1.73 m2, and albuminuria was categorized as a urinary albumin-creatinine ratio (UACR) of ≥ 30.0 mg/g. The results from quantile G-computation and BKMR indicated positive associations between exposure to the metal mixture and the prevalence of decreased eGFR and albuminuria (all P values < 0.05). These positive associations were mainly driven by blood Co, Cd, and Pb. Furthermore, blood Mn was identified as an influential element contributing to an inverse correlation with kidney dysfunction within metal mixtures. Increasing blood Se levels were negatively associated with the prevalence of decreased eGFR and positively associated with albuminuria. In addition, a potential pairwise interaction between Mn-Co on decreased eGFR was identified by BKMR analysis. Findings from our study suggested a positive association between exposure to the whole blood metal mixture and decreased kidney function, with blood Co, Pb, and Cd being the main contributors to this association, while Mn demonstrated an inverse relationship with renal dysfunction. However, as our study was cross-sectional in nature, further prospective studies are warranted to better understand the individual and combined effects of metals on kidney function.

Serum peroxiredoxin-4, a biomarker of oxidative stress, is associated with the development of nephropathy in patients with type 2 diabetes (Zodiac-65)

Oxidative stress is implicated in the development and progression of type 2 diabetes (T2D). Peroxiredoxin-4 is an antioxidant protein, which may serve as biomarker of oxidative stress, and has previously been associated with new-onset T2D. In this study, we investigated associations between circulating peroxiredoxin-4 and the risk of developing new-onset microvascular complications in T2D patients. Serum peroxiredoxin-4 was measured in 536 patients with T2D with (n = 257) and without (n = 279) baseline microvascular complications who participated in a primary-care based cohort study (Zwolle Outpatient Diabetes project Integrating Available Care [ZODIAC] study). Over a median follow-up of 3.4 years, 38 (13.6%) developed nephropathy, defined as albuminuria in two consecutive urine samples. In multivariable Cox proportional hazards regression analyses, peroxiredoxin-4 was associated with new-onset nephropathy (hazard ratio [HR] per doubling 1.78 [95% CI: 1.27-2.49], P < 0.001) after adjustment for potential confounding factors, including age, sex, disease duration, HbA1c levels, macrovascular complications, systolic blood pressure, and even high-sensitive C-reactive protein. There was no interaction of peroxiredoxin-4 with hs-CRP impacting on new-onset nephropathy. No significant associations were found with new-onset retinopathy or neuropathy. In conclusion, circulating peroxiredoxin-4 associates positively with an increased risk of developing nephropathy in T2D independent and irrespective of low-grade inflammation.

Role of ferroptosis in chronic kidney disease

Chronic kidney disease (CKD) has historically been a significant global health concern, profoundly impacting both life and well-being. In the process of CKD, with the gradual loss of renal function, the incidence of various life-threatening complications, such as cardiovascular diseases, cerebrovascular accident, infection and stroke, is also increasing rapidly. Unfortunately, existing treatments exhibit limited ability to halt the progression of kidney injury in CKD, emphasizing the urgent need to delve into the precise molecular mechanisms governing the occurrence and development of CKD while identifying novel therapeutic targets. Renal fibrosis, a typical pathological feature of CKD, plays a pivotal role in disrupting normal renal structures and the loss of renal function. Ferroptosis is a recently discovered iron-dependent form of cell death characterized by lipid peroxide accumulation. Ferroptosis has emerged as a potential key player in various diseases and the initiation of organ fibrosis. Substantial evidence suggests that ferroptosis may significantly contribute to the intricate interplay between CKD and its progression. This review comprehensively outlines the intricate relationship between CKD and ferroptosis in terms of iron metabolism and lipid peroxidation, and discusses the current landscape of pharmacological research on ferroptosis, shedding light on promising avenues for intervention. It further illustrates recent breakthroughs in ferroptosis-related regulatory mechanisms implicated in the progression of CKD, thereby providing new insights for CKD treatment. Video Abstract.

Zic family member 3 attenuates oxidative stress-induced vascular smooth muscle cell apoptosis in patients with chronic kidney disease

Neointimal hyperplasia is reportedly essential for arteriovenous fistulas (AVF) in patients undergoing hemodialysis. Oxidative stress is vital in the progression of uremic venous intimal hyperplasia. Studies have suggested that zinc ions obstruct vascular calcification in patients with chronic kidney disease (CKD). Recent studies have shown that the zinc finger protein, Zic family member 3 (ZIC3), is crucial for the earliest cardiovascular progenitors. ZIC3 mutations are associated with congenital heart disease. However, the mechanism of action of ZIC3 in vascular intimal hyperplasia in CKD remains unelucidated. Venous specimens were collected during primary AVF surgery and traumatic amputation, and serum samples were collected from patients with CKD and healthy controls. Mouse vascular smooth muscle cells (VSMCs) were treated with hydrogen peroxide (H2O2) to clarify the role of ZIC3 in CKD. ZIC3 expression was reduced in the veins of patients with uremia and the serum of those with CKD. Zic3 and Bcl2 levels were significantly decreased in mouse VSMCs treated with H2O2·H2O2 inhibited mouse VSMC activity, upregulated Bax, and cleaved caspase 3 expression. Following Zic3 overexpression, Bcl2 expression level and cell viability were elevated, whereas Bax and cleaved caspase 3 expression levels were downregulated. In contrast, Zic3 knockdown yielded the opposite results. Therefore, ZIC3 could be a new therapeutic target in venous neointimal hyperplasia of CKD.

Can curcumin supplementation break the vicious cycle of inflammation, oxidative stress, and uremia in patients undergoing peritoneal dialysis?

BACKGROUND & AIMS

Turmeric (a source of curcumin) is an excellent food to modulate oxidative stress, inflammation, and gut dysbiosis in patients with chronic kidney disease (CKD). However, no studies report the benefits of curcumin in patients undergoing peritoneal dialysis (PD). This study aims to evaluate the effects of curcuminoid supplementation on oxidative stress, inflammatory markers, and uremic toxins originating from gut microbiota in patients with CKD undergoing PD.

METHODS

This longitudinal, randomized, single-blind, placebo-controlled trial evaluated 48 patients who were randomized into two groups: Curcumin (three capsules of 500 mg of Curcuma longa extract, with 98.42 % total curcuminoids) or placebo (three capsules of 500 mg of starch) for twelve weeks. In the peripheral blood mononuclear cells (PBMCs), the transcriptional expression levels of Nrf2, HOX-1 and NF-κB were evaluated by quantitative real-time PCR. Oxidative stress was evaluated by malondialdehyde (MDA) and total Thiol (T-SH). TNF-α and IL-6 plasma levels were measured by ELISA. P-cresyl sulphate plasma level, a uremic toxin, was evaluated by high-performance liquid chromatography (HPLC) with fluorescent detection.

RESULTS

Twenty-four patients finished the study: 10 in the curcumin group (57.5 ± 11.6 years) and 14 in the placebo group (56.5 ± 10.0 years). The plasma levels of MDA were reduced after 12 weeks in the curcumin group (p = 0.01), while the placebo group remained unchanged. However, regarding the difference between the groups at the endpoint, no change was observed in MDA. Still, there was a trend to reduce the p-CS plasma levels in the curcumin group compared to the placebo group (p = 0.07). Likewise, the concentrations of protein thiols, mRNA expression of Nrf2, HOX-1, NF-κB, and cytokines plasma levels did not show significant changes.

CONCLUSION

Curcuminoid supplementation for twelve weeks attenuates lipid peroxidation and might reduce uremic toxin in patients with CKD undergoing PD. This study was registered on Clinicaltrials.gov as NCT04413266.

Effect and pharmacological mechanism of Salvia miltiorrhiza and its characteristic extracts on diabetic nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is a severe diabetic microvascular complication with an increasing prevalence rate and lack of effective treatment. Traditional Chinese medicine has been proven to have favorable efficacy on DN, especially Salvia miltiorrhiza Bunge (SM), one of the most critical and conventional herbs in the treatment. Over the past decades, studies have demonstrated that SM is a potential treatment for DN, and the exploration of the underlying mechanism has also received much attention.

AIM OF THIS REVIEW

This review aims to systematically study the efficacy and pharmacological mechanism of SM in the treatment of DN to understand its therapeutic potential more comprehensively.

MATERIALS AND METHODS

Relevant information was sourced from Google Scholar, PubMed, Web of Science, and CNKI databases.

RESULTS

Several clinical trials and systematic reviews have indicated that SM has definite benefits on the kidneys of diabetic patients. And many laboratory studies have further revealed that SM and its characteristic extracts, mainly including salvianolic acids and tanshinones, can exhibit pharmacological activity against DN by the regulation of metabolism, renal hemodynamic, oxidative stress, inflammation, fibrosis, autophagy, et cetera, and several involved signaling pathways, thereby preventing various renal cells from abnormal changes in DN, including endothelial cells, podocytes, epithelial cells, and mesangial cells.

CONCLUSION

As a potential drug for the treatment of DN, SM has multi-component, multi-target, and multi-pathway pharmacological effects. This work will not only verify the satisfactory curative effect of SM in the treatment of DN but also provide helpful insights for the development of new anti-DN drugs and the application of traditional Chinese medicine.

Kidney Fibrosis and Oxidative Stress: From Molecular Pathways to New Pharmacological Opportunities

Kidney fibrosis, diffused into the interstitium, vessels, and glomerulus, is the main pathologic feature associated with loss of renal function and chronic kidney disease (CKD). Fibrosis may be triggered in kidney diseases by different genetic and molecular insults. However, several studies have shown that fibrosis can be linked to oxidative stress and mitochondrial dysfunction in CKD. In this review, we will focus on three pathways that link oxidative stress and kidney fibrosis, namely: (i) hyperglycemia and mitochondrial energy imbalance, (ii) the mineralocorticoid signaling pathway, and (iii) the hypoxia-inducible factor (HIF) pathway. We selected these pathways because they are targeted by available medications capable of reducing kidney fibrosis, such as sodium-glucose cotransporter-2 (SGLT2) inhibitors, non-steroidal mineralocorticoid receptor antagonists (MRAs), and HIF-1alpha-prolyl hydroxylase inhibitors. These drugs have shown a reduction in oxidative stress in the kidney and a reduced collagen deposition across different CKD subtypes. However, there is still a long and winding road to a clear understanding of the anti-fibrotic effects of these compounds in humans, due to the inherent practical and ethical difficulties in obtaining sequential kidney biopsies and the lack of specific fibrosis biomarkers measurable in easily accessible matrices like urine. In this narrative review, we will describe these three pathways, their interconnections, and their link to and activity in oxidative stress and kidney fibrosis.

The nuclear factor kappa B signaling pathway is a master regulator of renal fibrosis

Renal fibrosis is increasingly recognized as a global public health problem. Acute kidney injury (AKI) and chronic kidney disease (CKD) both result in renal fibrosis. Oxidative stress and inflammation play central roles in progressive renal fibrosis. Oxidative stress and inflammation are closely linked and form a vicious cycle in which oxidative stress induces inflammation through various molecular mechanisms. Ample evidence has indicated that a hyperactive nuclear factor kappa B (NF-ƙB) signaling pathway plays a pivotal role in renal fibrosis. Hyperactive NF-ƙB causes the activation and recruitment of immune cells. Inflammation, in turn, triggers oxidative stress through the production of reactive oxygen species and nitrogen species by activating leukocytes and resident cells. These events mediate organ injury through apoptosis, necrosis, and fibrosis. Therefore, developing a strategy to target the NF-ƙB signaling pathway is important for the effective treatment of renal fibrosis. This Review summarizes the effect of the NF-ƙB signaling pathway on renal fibrosis in the context of AKI and CKD (immunoglobulin A nephropathy, membranous nephropathy, diabetic nephropathy, hypertensive nephropathy, and kidney transplantation). Therapies targeting the NF-ƙB signaling pathway, including natural products, are also discussed. In addition, NF-ƙB-dependent non-coding RNAs are involved in renal inflammation and fibrosis and are crucial targets in the development of effective treatments for kidney disease. This Review provides a clear pathophysiological rationale and specific concept-driven therapeutic strategy for the treatment of renal fibrosis by targeting the NF-ƙB signaling pathway.

Potential Underlying Mechanisms Explaining the Cardiorenal Benefits of Sodium-Glucose Cotransporter 2 Inhibitors

There is a bidirectional pathophysiological interaction between the heart and the kidneys, and prolonged physiological stress to the heart and/or the kidneys can cause adverse cardiorenal complications, including but not limited to subclinical cardiomyopathy, heart failure and chronic kidney disease. Whilst more common in individuals with Type 2 diabetes, cardiorenal complications also occur in the absence of diabetes. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) were initially approved to reduce hyperglycaemia in patients with Type 2 diabetes. Recently, these agents have been shown to significantly improve cardiovascular and renal outcomes in patients with and without Type 2 diabetes, demonstrating a robust reduction in hospitalisation for heart failure and reduced risk of progression of chronic kidney disease, thus gaining approval for use in treatment of heart failure and chronic kidney disease. Numerous potential mechanisms have been proposed to explain the cardiorenal effects of SGLT2i. This review provides a simplified summary of key potential cardiac and renal mechanisms underlying the cardiorenal benefits of SGT2i and explains these mechanisms in the clinical context. Key mechanisms related to the clinical effects of SGLT2i on the heart and kidneys explained in this publication include their impact on (1) tissue oxygen delivery, hypoxia and resultant ischaemic injury, (2) vascular health and function, (3) substrate utilisation and metabolic health and (4) cardiac remodelling. Knowing the mechanisms responsible for SGLT2i-imparted cardiorenal benefits in the clinical outcomes will help healthcare practitioners to identify more patients that can benefit from the use of SGLT2i.

Effect of octreotide on oxidative stress in the erythrocyte and kidney tissue in adriamycin-induced experimental nephrotic syndrome model

INTRODUCTION

Nephrotic syndrome (NS) is one of the reasons of end-stage kidney disease, and elucidating the pathogenesis and offer new treatment options is important. Oxidative stress might trigger pathogenesis systemically or isolated in the kidneys. Octreotide (OCT) has beneficial antioxidant effects. We aimed to investigate the source of oxidative stress and the effect of OCT on experimental NS model.

METHODS

Twenty-four non-uremic Wistar albino rats were divided into 3 groups. Control group, 2 mL saline intramuscular (im); NS group, adriamycin 5 mg/kg intravenous (iv); NS treatment group, adriamycin 5 mg/kg (iv) and OCT 200 mcg/kg (im) were administered at baseline (Day 0). At the end of 21 days, creatinine and protein levels were measured in 24-hour urine samples. Erythrocyte and renal catalase (CAT) and thiobarbituric acid reactive substance (TBARS) were measured. Renal histology was also evaluated.

RESULTS

There was no significant difference among the 3 groups in terms of CAT and TBARS in erythrocytes. Renal CAT level was lowest in NS group, and significantly lower than the control group. In treatment group, CAT level significantly increased compared with NS group. In terms of renal histology, tubular and interstitial evaluations were similar in all groups. Glomerular score was significantly higher in NS group compared with control group and it was significantly decreased in treatment group compared to NS group.

CONCLUSIONS

Oxidative stress in NS might be due to the decrease in antioxidant protection mechanism in kidney. Octreotide improves antioxidant levels and histology in renal tissue and might be a treatment option.

Therapeutic mechanism exploration of polysaccharides from Dendrobium officinale on unilateral ureteral obstruction operation-induced renal fibrosis based on improving oxidative stress injury mediated by AhR/NOX4 pathway

Dendrobium officinale polysaccharides (DOP) has been reported to possess remarkable effects on improving renal function, oxidative stress damage and fibrotic diseases. However, the role and mechanism of DOP in preventing and treating renal fibrosis remain unclear. The purpose of this paper was to explore the therapeutic effects and underlying mechanisms of DOP on renal fibrosis. Firstly, renal fibrosis model was induced by unilateral ureteral obstruction operation (UUO) in male BALB/c mice. Subsequently, the anti-renal fibrosis effect of DOP was evaluated. It turned out that DOP significantly attenuated UUO induced renal fibrosis. The beneficial effects of DOP on renal fibrosis were concretely manifested in the relief of clinical symptoms, improvement of renal function, reduction of extracellular matrix collagen aggregation, attenuation of structural damage and inflammation, and decrement of profibrotic factors secretion. Meanwhile, DOP could also alleviate oxidative stress injury and inhibit the AhR/NOX4 pathway proteins expression. Furthermore, multivariate statistical analysis, AhR interference and overexpression experiments showed that the effect of DOP on alleviating renal fibrosis was closely related to the improvement of oxidative stress injury mediated by the AhR/NOX4 pathway. Overall, the data in the present paper indicated that DOP could alleviate renal fibrosis through improving AhR/NOX4 mediated oxidative stress injury.

[Linagliptin improves diabetic kidney disease in rats by promoting mitochondrial biogenesis through the AMPK/PGC-1α/TFAM pathway]

OBJECTIVE

To investigate whether linagliptin improves diabetic kidney disease (DKD) by promoting mitochondrial biosynthesis via activating adenosine monophosphate activated protein kinase/peroxisome proliferator-activated receptor gamma coactivator 1α/mitochondrial transcription factor A (AMPK/PGC-1α/TFAM) pathway.

METHODS

With 6 male SD rats feeding normal chow as the control group, 16 SD rat models of DKD induced by intraperitoneal injection of 45 mg/kg STZ and high-fat and high-glucose feeding for 4 weeks were randomized into DKD model group and linagliptin treatment group. The rats in the latter two groups were subjected to daily intragastric administration of vehicle or 5 mg/kg linagliptin (dissolved in 5 g/L sodium carboxymethylcellulose, final concentration of 2 mg/mL) for 12 weeks with further high-fat and high-glucose feeding. After the treatments, the rats were sacrificed and blood samples from the abdominal aorta and kidney tissues were collected for testing blood glucose, liver function and lipid metabolism; HE, PAS, Masson, Sirius red staining and electron microscopy were used to observe renal tissue damage. Renal expressions of transforming growth factor β1 (TGF-β1), fibronectin (FN) and collagen I (Col I) were detected by immunohistochemistry, and the changes in membrane potential (ΔψM) and ATP enzyme content were analyzed to assess mitochondrial damage; The expressions of AMPK/PGC-1α/TFAM pathway proteins were detected using Western blotting.

RESULTS

Compared with DKD model rats, the rats receiving linagliptin treatment showed significantly decreased blood glucose level (P < 0.01) and improved proteinuria (P < 0.05) with obviously alleviated renal ultrastructural damage and fibrosis, increased ATPase content and ΔψM (P < 0.0001), and enhanced renal expressions of P-AMPK/AMPK, PGC-1α and TFAM (P < 0.05).

CONCLUSIONS

Linagliptin improves proteinuria and renal fibrosis in rat models of DKD possibly by activating the AMPK/PGC-1α/TFAM pathway to promote mitochondrial biosynthesis.

Adenine model of chronic renal failure in rats to determine whether MCC950, an NLRP3 inflammasome inhibitor, is a renopreventive

BACKGROUND

Chronic renal failure (CRF) is defined by a significant decline in renal function that results in decreased salt filtration and inhibition of tubular reabsorption, which ultimately causes volume enlargement. This study evaluated the potential renopreventive effects of the NLRP3 inflammasome inhibitor MCC950 in adenine-induced CRF in rats due to conflicting evidence on the effects of MCC950 on the kidney.

METHODS

Since the majority of the kidney tubular abnormalities identified in people with chronic renal disease are comparable to those caused by adding 0.75 percent of adenine powder to a rat's diet each day for four weeks, this method has received broad approval as a model for evaluating kidney damage. Throughout the test, blood pressure was checked weekly and at the beginning. Additionally, oxidative stress factors, urine sample examination, histological modifications, and immunohistochemical adjustments of caspase-3 and interleukin-1 beta (IL-1) levels in renal tissues were carried out.

RESULTS

Results revealed that MCC950, an inhibitor of the NLRP3 inflammasome, had a renopreventive effect, which was demonstrated by a reduction in blood pressure readings and an improvement in urine, serum, and renal tissue indicators that indicate organ damage. This was also demonstrated by the decrease in neutrophil gelatinase-associated lipocalin tubular expression (NGAL). The NLRP3 inflammasome inhibitor MCC950 was found to significantly alleviate the worsening renal cellular alterations evidenced by increased expression of caspase-3 and IL-1, according to immunohistochemical tests.

CONCLUSION

The NLRP3 inflammasome inhibitor MCC950 demonstrated renopreventive effects in the CRF rat model, suggesting that it might be used as a treatment strategy to stop the progression of CRF.

Low intensity pulsed ultrasound ameliorates Adriamycin-induced chronic renal injury by inhibiting ferroptosis

OBJECTIVE

It is very important to develop a new therapeutic strategy to cope with the increasing morbidity and mortality of chronic kidney disease (CKD). As a kind of physical therapy, low intensity pulsed ultrasound (LIPUS) has remarkable anti-inflammatory and repair-promoting effects and is expected to become a new therapeutic method for CKD. This study aims to clarify the treatment effect of LIPUS on CKD-related renal inflammation and fibrosis, and to further explore the potential signal network of LIPUS treatment for ameliorating chronic renal injury.

METHODS

A rat model simulating the progress of CKD was established by twice tail-vein injection of Adriamycin (ADR). Under anesthesia, bilateral kidneys of CKD rats were continuously stimulated by LIPUS for four weeks. The parameters of LIPUS were 1.0 MHz, 60 mW/cm2, 50% duty cycle and 20 min/d.

RESULTS

LIPUS treatment effectively inhibited ADR-induced renal inflammation and fibrosis, and improved CKD-related to oxidative stress and ferroptosis. In addition, the therapeutic effect of LIPUS is closely related to the regulation of TGF-β1/Smad and Nrf2/keap1/HO-1 signalling pathways.

DISCUSSION

This study provides a new direction for further mechanism research and lays an important foundation for clinical trials.

Identification of key biomarkers of the glomerulus in focal segmental glomerulosclerosis and their relationship with immune cell infiltration based on WGCNA and the LASSO algorithm

OBJECTIVE

The aim of our study was to identify key biomarkers of glomeruli in focal glomerulosclerosis (FSGS) and analyze their relationship with the infiltration of immune cells.

METHODS

The expression profiles (GSE108109 and GSE200828) were obtained from the GEO database. The differentially expressed genes (DEGs) were filtered and analyzed by gene set enrichment analysis (GSEA). MCODE module was constructed. Weighted gene coexpression network analysis (WGCNA) was performed to obtain the core gene modules. Least absolute shrinkage and selection operator (LASSO) regression was applied to identify key genes. ROC curves were employed to explore their diagnostic accuracy. Transcription factor prediction of the key biomarkers was performed using the Cytoscape plugin IRegulon. The analysis of the infiltration of 28 immune cells and their correlation with the key biomarkers were performed.

RESULTS

A total of 1474 DEGs were identified. Their functions were mostly related to immune-related diseases and signaling pathways. MCODE identified five modules. The turquoise module of WGCNA had significant relevance to the glomerulus in FSGS. TGFB1 and NOTCH1 were identified as potential key glomerular biomarkers in FSGS. Eighteen transcription factors were obtained from the two hub genes. Immune infiltration showed significant correlations with T cells. The results of immune cell infiltration and their relationship with key biomarkers implied that NOTCH1 and TGFB1 were enhanced in immune-related pathways.

CONCLUSION

TGFB1 and NOTCH1 may be strongly correlated with the pathogenesis of the glomerulus in FSGS and are new candidate key biomarkers. T-cell infiltration plays an essential role in the FSGS lesion process.

The association between skipping breakfast and chronic kidney disease

BACKGROUND/OBJECTIVES

There are few reports on the relationship between skipping breakfast and chronic kidney disease (CKD). We examined the skipping breakfast-CKD relationship and the mediation effects of metabolic diseases (obesity, hypertension, and diabetes) on this relationship.

SUBJECTS/METHODS

We analyzed the data of 21,138 participants aged ≥ 40 years from the Korea National Health and Nutrition Examination Survey 2013-2018. Skipping breakfast was defined as rarely eating breakfast over the past year. CKD was defined as decreased kidney function expressed by an estimated glomerular filtration rate of < 60 mL/min/1.73 m2. We used a complex sample logistic regression model to examine the relationship between skipping breakfast and CKD. We used Baron and Kenny's approach to examine whether metabolic diseases work as a mediator within the skipping breakfast-CKD relationships.

RESULTS

About 7.6% of participants skipped breakfast, and 5.5% had CKD. After adjusting for confounders, participants who skipped breakfast were at higher odds of having CKD (odds ratio 1.61; 95% confidence interval 1.07-2.42; p value 0.021) compared to those who did not skip breakfast. With full adjustments for confounders, skipping breakfast was not significantly associated with any metabolic diseases, while CKD was significantly associated with diabetes and hypertension.

CONCLUSION

We found that middle-aged or older people who skipped breakfast had a significantly higher odds of having CKD compared to those who did not skip breakfast. However, metabolic diseases did not mediate the relationship between skipping breakfast and CKD.

Circular RNAs: An emerging precise weapon for diabetic nephropathy diagnosis and therapy

Diabetic nephropathy (DN) is a prevalent chronic microvascular complication associated with diabetes mellitus and represents a major cause of chronic kidney disease and renal failure. Current treatment strategies for DN primarily focus on symptom alleviation, lacking effective approaches to halt or reverse DN progression. Circular RNA (circRNA), characterized by a closed-loop structure, has emerged as a novel non-coding RNA regulator of gene expression, attributed to its conservation, stability, specificity, and multifunctionality. Dysregulation of circRNA expression is closely associated with DN progression, whereby circRNA impacts kidney cell injury by modulating cell cycle, differentiation, cell death, as well as influencing the release of inflammatory factors and stromal fibronectin expression. Consequently, circRNA is considered a predictive biomarker and a potential therapeutic target for DN. This review provides an overview of the latest research progress in the classification, functions, monitoring methods, and databases related to circRNA. The paper focuses on elucidating the impact and underlying mechanisms of circRNA on kidney cells under diabetic conditions, aiming to offer novel insights into the prevention, diagnosis, and treatment of DN.

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.

Immunohistochemical analysis of renal oxidative damage in senior and geriatric cats with chronic kidney disease

Oxidative stress is a well-known cause of chronic kidney disease (CKD). In this study, renal oxidative damage in azotaemic and non-azotaemic aged cats with naturally occurring CKD was investigated using immunohistochemistry for 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 4-hydroxynonenal (4-HNE) as markers of oxidative tissue damage. Kidneys were obtained from aged (>10 years old) azotaemic (n = 13) and non-azotaemic (n = 7) cats. Immunoreactivity for 8-OHdG was found in the nuclei of glomeruli, proximal and distal tubules, loops of Henle and collecting ducts, whereas 4-HNE-positive signals were detected in the cytoplasm of distal nephrons in azotaemic and non-azotaemic cats. Quantitative analysis did not identify any significant differences between the azotaemic and non-azotaemic groups for any of the parameters examined. These results indicate that renal oxidative damage occurs in the kidneys of aged cats with CKD, regardless of whether they are azotaemic or non-azotaemic, emphasizing the importance of oxidative stress during early-stage CKD in senior and geriatric cats.

LncRNA H19: a novel player in the regulation of diabetic kidney disease

Diabetic kidney disease (DKD), one of the most severe complications of diabetes mellitus (DM), has received considerable attention owing to its increasing prevalence and contribution to chronic kidney disease (CKD) and end-stage kidney disease (ESRD). However, the use of drugs targeting DKD remains limited. Recent data suggest that long non-coding RNAs (lncRNAs) play a vital role in the development of DKD. The lncRNA H19 is the first imprinted gene, which is expressed in the embryo and down-regulated at birth, and its role in tumors has long been a subject of controversy, however, in recent years, it has received increasing attention in kidney disease. The LncRNA H19 is engaged in the pathological progression of DKD, including glomerulosclerosis and tubulointerstitial fibrosis via the induction of inflammatory responses, apoptosis, ferroptosis, pyroptosis, autophagy, and oxidative damage. In this review, we highlight the most recent research on the molecular mechanism and regulatory forms of lncRNA H19 in DKD, including epigenetic, post-transcriptional, and post-translational regulation, providing a new predictive marker and therapeutic target for the management of DKD.

High-sulfated derivative of polysaccharide from Ulva pertusa improves Adriamycin-induced nephrotic syndrome by suppressing oxidative stress

Nephrotic syndrome (NS) is characterized by proteinuria, hyperlipidemia, and hypoalbuminemia. Ulva pertusa, a green seaweed, is a nutritional supplement. In this study, the high-sulfated derivative of Ulva pertusa polysaccharide (HU) was prepared by combining U pertusa polysaccharide with chlorosulfonic acid. The NS rat model was established by tail vein single injection of Adriamycin (6.0 mg kg-1). Normal rats were used as the control group. NS rat models were treated with HU or U (173 mg kg-1 day-1). After treatment for 6 weeks, we assessed urine protein, renal function, and blood lipids, and observed morphology and histologic injury of the kidney and glomerular microstructure. Furthermore, we detected antioxidant enzyme activity and expression level of the Keap1/Nrf2 signaling pathway to explore the potential mechanism of HU. Results showed that HU not only alleviated hyperlipidemia and hypoalbuminemia, but also reduced urine protein by inhibiting podocyte detachment, thickening of the glomerular basement membrane, and expression of kidney fibrosis markers (collagens I and IV). In addition, HU enhanced antioxidant enzyme activity (GSH-Px, CAT, SOD) in both serum and the kidney, which may be due to upregulating the expression of Nrf2 and downregulating the expression of Keap1. In conclusion, HU appears to be effective in attenuating NS in rats through suppressing oxidative stress by regulating the Keap1/Nrf2 signaling pathway.

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.

Muscle Strength and Biochemical Markers as Predictors of Depression in Hemodialysis Patients: A Cross-Sectional Study

Patients with chronic renal failure, many of which treated with hemodialysis, present a high prevalence of impaired muscle strength which suggest that muscle mass parameters may be used as markers for changes in muscle in these patients. Measurement of handgrip strength (HGS) is a common, simple, and quick measure of muscle function an indicator of overall muscle strength which has been associated with physical activity and several anthropometric traits. Intercellular adhesion molecule-1 (ICAM-1) and insulin-like growth factor-1 (IGF-1) are biochemical markers associated with inflammatory processes which are a common consequence of dialysis. Additionally, hemodialysis patients frequently present signs of malnutrition and depression. This cross-sectional study aimed to evaluate if muscle and biochemical markers could be used to predict the risk of depression in hemodialysis patients. Several anthropometric parameters, nutrient intake, depression state and the serum levels of ICAM-1 and IGF-1 were determined and Pearson's correlation coefficient and/or Spearman's correlation coefficient were used to test the correlation between them. Our results do not show a correlation between HGF, IGF-1 and ICAM-1 with the depression status of the patients, but mid-arm muscle circumference (MAMC) was statistically and positively correlated with depression. Additionally, ICAM-1 levels were negatively correlated with HGS, MAMC, and IGF-1. Overall, the results of the present study suggest that HGS may be used as an indicator of cardiovascular diseases and MAMC may be a good predictor of the level of depression in hemodialysis patients, although further studies are required.

The Anti-Inflammatory Action of Pulsed Radiofrequency-A Hypothesis and Potential Applications

In 2013, it was reported that pulsed radiofrequency (PRF) could be applied to obtain a systemic anti-inflammatory effect. Patients with chronic pain and patients with an inflammatory condition from other disciplines could potentially profit from this finding. At that time, intravenous application was used, but since then, it became clear that it could be applied transcutaneously as well. This procedure was named RedoxPRF. This can be used both for regional and for systemic application. Recently, the basic element of the mode of action has been clarified from the analysis of the effects of PRF on a standard model of muscle injury in rats. The objective of this paper is to present a hypothesis on the mode of action of RedoxPRF now that the basic mechanism has become known. Cell stress causes an increased production of free radicals, disturbing the redox equilibrium, causing oxidative stress (OS) either directly or secondarily by other types of stress. Eventually, OS causes inflammation and an increased sympathetic (nervous) system activity. In the acute form, this leads to immune paralysis; in the chronic form, to immune tolerance and chronic inflammation. It is hypothesized that RedoxPRF causes a reduction of free radicals by a recombination of radical pairs. For systemic application, the target cells are the intravascular immune cells that pass through an activated area as on an assembly line. Hypothesis conclusions: 1. RedoxPRF treatment works selectively on OS. It has the unique position of having a point of engagement at the most upstream level of the train of events. 2. RedoxPRF has the potential of being a useful tool in the treatment of inflammatory diseases and possibly of stage 4 cancer. 3. In the treatment of chronic pain, RedoxPRF is an entirely new method because it is different from ablation as well as from stimulation. We propose the term "functional restoration". 4. Controlled studies must be conducted to develop this promising new field in medicine further.