Reactive Oxygen Species and Redox Signaling in Chronic Kidney Disease

Integrated approach to reducing polypharmacy in older people: exploring the role of oxidative stress and antioxidant potential therapy

Increased life expectancy, attributed to improved access to healthcare and drug development, has led to an increase in multimorbidity, a key contributor to polypharmacy. Polypharmacy is characterised by its association with a variety of adverse events in the older persons. The mechanisms involved in the development of age-related chronic diseases are largely unknown; however, altered redox homeostasis due to ageing is one of the main theories. In this context, the present review explores the development and interaction between different age-related diseases, mainly linked by oxidative stress. In addition, drug interactions in the treatment of various diseases are described, emphasising that the holistic management of older people and their pathologies should prevail over the individual treatment of each condition.

Therapeutic potential of bark extracts from Macaranga denticulata on renal fibrosis in streptozotocin-induced diabetic rats

Macaranga denticulata (MD) bark is commonly utilized in traditional medicine for diabetes prevention and treatment. The bark extract of MD is rich in prenyl or farnesyl flavonoids and stilbenes, which possess antioxidant properties. Although data suggest the potential therapeutic benefits of the use of MD in treating diabetic nephropathy (DN), the precise mechanisms underlying MD-initiated protective effects against DN are not well understood. This study aimed to assess the renoprotective properties of MD extract by examining renofibrosis inhibition, oxidative stress, and inflammation utilizing streptozotocin-induced DN male Sprague - Dawley rats. Diabetic rats were intraperitoneally injected with streptozotocin (STZ) to induce diabetes. After 6 days, these rats were orally administered MD extract (200 mg/kg/day) or metformin (200 mg/kg/day) for 14 days. The administration of MD extract significantly lowered blood glucose levels, restored body weight, and reduced urine levels of various biomarkers associated with kidney functions. Histopathological analysis revealed protective effects in both kidneys and pancreas. Further, MD extract significantly restored abnormalities in advanced glycation end products, oxidative stress biomarkers, and proinflammatory cytokine levels in STZ-treated rats. MD extract markedly reduced renal fibrosis biomarker levels, indicating recovery from renal injury, and reversed dysregulation of sirtuins and claudin-1 in the kidneys of rats with STZ-induced diabetes. In conclusion, data demonstrated the renoprotective role of MD extract, indicating plant extract's ability to suppress oxidative stress and regulate proinflammatory pathways during pathological changes in diabetic nephropathy.

Butin Protects Keratinocytes From Particulate Matter 2.5 and Ultraviolet B-Mediated Damages

BACKGROUND

Butin is a naturally occurring compound with a wide range of medicinal properties, including anti-inflammatory, anti-arthritic, and antioxidant properties. Particulate matter 2.5 (PM2.5) and ultraviolet B (UVB) radiation contribute to skin cell damage via the induction of oxidative stress.

METHODS

This study sought to assess the protective effects of butin against damage triggered by PM2.5 and UVB in human HaCaT keratinocytes. Assessments were performed to evaluate cell viability, apoptosis, and cellular component damage.

RESULTS

Butin exhibited its protective ability via the inhibition of PM2.5-induced reactive oxygen species generation, lipid peroxidation, DNA damage, protein carbonylation, and mitochondrial damage. Butin reduced the PM2.5-induced c-Fos and phospho-c-Jun protein levels as well as mitogen-activated protein kinase. Furthermore, butin mitigated PM2.5- and UVB-induced apoptosis.

CONCLUSION

Butin had the potential as a pharmaceutical candidate for treating skin damage caused by PM2.5 and UVB exposure.

Sildenafil and furosemide nanoparticles as a novel pharmacological treatment for acute renal failure in rats

Hospitalized patients often develop acute renal failure (ARF), which causes severe morbidity and death. This research investigates the potential renoprotective benefits of sildenafil and furosemide in glycerol-induced ARF, and measures kidney function metrics in response to nanoparticle versions of these medications. Inducing ARF is commonly done by injecting 50% glycerol intramuscularly. Rats underwent a 24-h period of dehydration and starvation before slaughter for renal function testing. We investigated urine analysis, markers of oxidative stress, histology of kidney tissue, immunohistochemistry analysis of caspase-3 and interleukin-1 beta (IL-1 β), kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL), which are specific indicators of kidney tissue damage. The results of our study showed that the combination of sildenafil and furosemide, using both traditional and nanoparticle formulations, had a greater protective effect on the kidneys compared to using either drug alone. The recovery of renal tissue indicators, serum markers, and urine markers, which are indicative of organ damage, provides evidence of improvement. This was also indicated by the reduction in KIM-1 and NGAL tubular expression. The immunohistochemistry tests showed that the combination therapy, especially with the nanoforms, greatly improved the damaged cellular changes in the kidneys, as shown by higher levels of caspase-3 and IL-1β. According to the findings, a glycerol-induced rat model demonstrates that sildenafil and furosemide, either alone or in combination, in conventional or nanoparticulate forms, improve ARF dysfunction. The synergistic nanoparticulate compositions show remarkable effectiveness. This observation highlights the possible therapeutic implications for ARF treatment.

Exploring the effects of 4-chloro-o-phenylenediamine on human fibrinogen: A comprehensive investigation via biochemical, biophysical and computational approaches

Fibrinogen (Fg), an essential plasma glycoprotein involved in the coagulation cascade, undergoes structural alterations upon exposure to various chemicals, impacting its functionality and contributing to pathological conditions. This research article explored the effects of 4-Chloro-o-phenylenediamine (4-Cl-o-PD), a common hair dye component (IUPAC = 1-Chloro-3,4-diaminobenzene), on human fibrinogen through comprehensive computational, biophysical, and biochemical approaches. The formation of a stable ligand-protein complex is confirmed through molecular docking and molecular dynamics simulations, revealing possible interaction having a favorable -4.8 kcal/mol binding energy. Biophysical results, including UV-vis and fluorescence spectroscopies, corroborated with the computational findings, whereas Fourier transform infrared spectroscopy (FT-IR) and circular dichroism spectroscopy (CD) provide insights into the alterations of secondary structures upon interaction with 4-Cl-o-PD. Anilinonaphthalene-sulfonic acid (ANS) fluorescence showed a partially unfolded protein, with enhanced α to β-sheet transition as evidenced by thioflavin T (ThT) spectroscopy and microscopy. Moreover, biochemical assays confirmed the formation of carbonyl compounds that may be responsible for the oxidation of methionine residues in fibrinogen. Electrophoresis and electron microscopy confirmed the formation of aggregates. Our findings elucidate the interaction pattern of 4-Cl-o-PD with Fg, leading to structural perturbation, which may have potential implications for fibrinogen misfolding or its aggregation. Protein aggregation or its misfolded products affect peripheral tissues and the central nervous system. Many chronic progressive diseases, like type II diabetes mellitus, Alzheimer's disease, Parkison's disease, and Creutzfeldt-Jakob disease are associated with intrinsically aberrant disordered proteins. Understanding these interactions may offer new perspectives on the safety and biocompatibility of dye compounds, which may contribute to developing improved strategies for acquired amyloidogenesis.

Imperatorin ameliorates ferroptotic cell death, inflammation, and renal fibrosis in a unilateral ureteral obstruction mouse model

BACKGROUND

Imperatorin is a naturally occurring furocoumarin derivative found in traditional Chinese medicine Angelica dahurica for its anticancer, antihypertensive, and antidiabetic properties. Chronic kidney disease (CKD) is a global health issue, characterized by a high prevalence, significant morbidity and mortality, and a range of related complications.

OBJECTIVE

This study aims to investigate the protective effects of imperatorin treatment and the specific underlying mechanisms in progressive CKD.

METHODS

Imperatorin was orally administrated for 14 consecutive days to mice with unilateral ureteral obstruction (UUO) to investigate the renal pathological alternations, pro-inflammatory mediators, antioxidant response, and ferroptotic death signaling. Imperatorin was also tested in the erastin-induced injury of renal proximal tubular cells (NRK-52E). Cell viability, ferroptosis protein markers, erastin-induced oxidative stress, and lipid peroxidation were assessed.

RESULTS

In vivo, imperatorin treatment alleviated kidney histology alternations and attenuated the protein expression of fibrotic markers. Furthermore, imperatorin administration reduced inflammatory cell infiltration, and alleviated the oxidative stress burden by downregulating protein markers such as catalase, superoxide dismutase 2 (SOD-2), NADPH oxidase 4 (NOX-4), and thioredoxin reductase 1 (Trxr-1). It also mitigated ferroptosis markers such as glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11/cystine transporter (SLC7A11/xCT), and transferrin receptor 1 (TFR-1), and attenuated renal cell apoptosis. In vitro, imperatorin treatment effectively decreased erastin-induced feroptotic cell death, restored the antioxidant enzyme levels, and mitigated lipid peroxidation as well as the expression of ferroptosis-related markers (XCT, GPX4, and p-p53) in a dose-dependent manner.

CONCLUSION

Our finding demonstrated for the first time, that imperatorin treatment holds therapeutic potential in a UUO mouse model of CKD and inhibits the erastin-induced oxidative stress, ferroptosis, and subsequent lipid peroxidation in vitro. This highlights the potential of imperatorin as a future therapeutic target for ferroptosis to improve the progression of CKD.

Evaluating nephrotoxicity reduction in a novel polymyxin B formulation: insights from a 3D kidney-on-a-chip model

This study aimed to assess the nephrotoxicity associated with VRP-034 (novel formulation of polymyxin B [PMB]) compared to marketed PMB in a three-dimensional (3D) kidney-on-a-chip model. To model the human kidney proximal tubule for analysis, tubular structures were established using 23 triple-channel chips seeded with RPTEC/hTERT1 cells. These cells were exposed to VRP-034 or PMB at seven concentrations (1-200 µM) over 12, 24, and 48 h. A suite of novel kidney injury biomarkers, cell health, and inflammatory markers were quantitatively assessed in the effluent. Additionally, caspase and cytochrome C levels were measured, and cell viability was evaluated using calcein AM and ethidium homodimer-1 (EthD-1). Exposure to marketed PMB resulted in significantly elevated levels (P < 0.05) of four key biomarkers (KIM-1, cystatin C, clusterin, and OPN) compared to VRP-034, particularly at clinically relevant concentrations of ≥10 µM. At 25 µM, all biomarkers demonstrated a significant increase (P < 0.05) with marketed PMB exposure compared to VRP-034. Inflammatory markers (interleukin-6 and interleukin-8) increased significantly (P < 0.05) with marketed PMB at concentrations of ≥5 µM, relative to VRP-034. VRP-034 displayed superior cell health outcomes, exhibiting lower lactate dehydrogenase release, while ATP levels remained comparable. Morphological analysis revealed that marketed PMB induced more severe damage, disrupting tubular integrity. Both treatments activated cytochrome C, caspase-3, caspase-8, caspase-9, and caspase-12 in a concentration-dependent manner; however, caspase activation was significantly reduced (P < 0.05) with VRP-034. This study demonstrates that VRP-034 significantly reduces nephrotoxicity compared to marketed PMB within a 3D microphysiological system, suggesting its potential to enable the use of full therapeutic doses of PMB with an improved safety profile, addressing the need for less nephrotoxic polymyxin antibiotics.

Mechanisms and therapeutic targets of carbon monoxide poisoning: A focus on reactive oxygen species

Carbon monoxide (CO) poisoning presents a substantial public health challenge that necessitates the identification of its pathological mechanisms and therapeutic targets. CO toxicity arises from tissue hypoxia-ischemia secondary to carboxyhemoglobin formation, and cellular damage mediated by CO at the cellular level. The mitochondria are the major targets of neuronal damage caused by CO. Under normal physiological conditions, mitochondria produce reactive oxygen species (ROS), which are byproducts of aerobic metabolism. While low ROS levels are crucial for essential cellular functions, including signal transduction, differentiation, responses to hypoxia and immunity, transcriptional regulation, and autophagy, excess ROS become pathological and exacerbate CO poisoning. This review presents the evidence of elevated ROS being associated with the progression of CO poisoning. Antioxidant treatments targeting ROS removal have been proven effective in mitigating CO poisoning, underscoring their therapeutic potential. In this review, we highlight the latest advances in the understanding of the role and the clinical implications of ROS in CO poisoning. We focus on cellular sources of ROS, the molecular mechanisms underlying mitochondrial oxidative stress, and potential therapeutic strategies for targeting ROS in CO poisoning.

Paricalcitol prevents renal tubular injury induced by ischemia-reperfusion: Role of oxidative stress, inflammation and AT1R

The vitamin D receptor (VDR) is associated with antioxidative and anti-inflammatory effects and modulation of the renin-angiotensin-aldosterone system. This study evaluated whether VDR agonist paricalcitol protects renal ischemia-reperfusion (IR) induced tubular injury in rats by evaluating: 1) ATP-dependent tubular Na+ transport; 2) renal redox signaling; 3) renal content of proinflammatory cytokines TNF-α and IL-6; and 4) renal content of renin and angiotensin II receptor type 1 (AT1R). Paricalcitol prevented IR-induced tubular injury, evidenced by the prevention of histopathological changes and renal fibrosis with preservation of the activity of ATP-dependent Na+ transporters in the renal cortex. Paricalcitol decreased renal oxidative stress by reducing NADPH oxidase activity and increasing catalase. Paricalcitol also decreased the renal content of TNF-α, IL-6, and AT1R. The NADPH oxidase inhibitor apocynin did not present additive protection to paricalcitol-induced effects. The protective effects of paricalcitol on tubular injury induced by renal IR may dependent on the modulation of redox and proinflammatory signaling and renal angiotensin II/AT1R signaling.

Natural polysaccharides as promising reno-protective agents for the treatment of various kidney injury

Renal injury, a prevalent clinical outcome with multifactorial etiology, imposes a substantial burden on society. Currently, there remains a lack of effective management and treatments. Extensive research has emphasized the diverse biological effects of natural polysaccharides, which exhibit promising potential for mitigating renal damage. This review commences with the pathogenesis of four common renal diseases and the shared mechanisms underlying renal injury. The renoprotective roles of polysaccharides in vivo and in vitro are summarized in the following five aspects: anti-oxidative stress effects, anti-apoptotic effects, anti-inflammatory effects, anti-fibrotic effects, and gut modulatory effects. Furthermore, we explore the structure-activity relationship and bioavailability of polysaccharides in relation to renal injury, as well as investigate their utility as biomaterials for alleviating renal injury. The clinical experiments of polysaccharides applied to patients with chronic kidney disease are also reviewed. Broadly, this review provides a comprehensive perspective on the research direction of natural polysaccharides in the context of renal injury, with the primary aim to serve as a reference for the clinical development of polysaccharides as pharmaceuticals and prebiotics for the treatment of kidney diseases.

Metabolism and bioenergetics in the pathophysiology of organ fibrosis

Fibrosis is the tissue scarring characterized by excess deposition of extracellular matrix (ECM) proteins, mainly collagens. A fibrotic response can take place in any tissue of the body and is the result of an imbalanced reaction to inflammation and wound healing. Metabolism has emerged as a major driver of fibrotic diseases. While glycolytic shifts appear to be a key metabolic switch in activated stromal ECM-producing cells, several other cell types such as immune cells, whose functions are intricately connected to their metabolic characteristics, form a complex network of pro-fibrotic cellular crosstalk. This review purports to clarify shared and particular cellular responses and mechanisms across organs and etiologies. We discuss the impact of the cell-type specific metabolic reprogramming in fibrotic diseases in both experimental and human pathology settings, providing a rationale for new therapeutic interventions based on metabolism-targeted antifibrotic agents.

The main molecular mechanisms of ferroptosis and its role in chronic kidney disease

The term ferroptosis, coined in 2012, has been widely applied in various disease research fields. Ferroptosis is a newly regulated form of cell death distinct from apoptosis, necrosis, and autophagy, the mechanisms of which have been extensively studied. Chronic kidney disease, characterized by renal dysfunction, is a common disease severely affecting human health, with its occurrence and development influenced by multiple factors and leading to dysfunction in multiple systems. It often lacks obvious clinical symptoms in the early stages, and thus, diagnosis is typically made in the later stages, complicating treatment. While research on ferroptosis and acute kidney injury has made continuous progress, studies on the association between ferroptosis and chronic kidney disease remain limited. This review aims to summarize chronic kidney disease, investigate the mechanism and regulation of ferroptosis, and attempt to elucidate the role of ferroptosis in the occurrence and development of chronic kidney disease.

Sex-related differences in SIRT3-mediated mitochondrial dynamics in renal ischemia/reperfusion injury

The prevalence of renal ischemia/reperfusion injury (IRI) in premenopausal women is considerably lower than that in age-matched men. This suggests that sex-related differences in mitochondrial function and homeostasis may contribute to sexual dimorphism in renal injury, though the mechanism remains unclear. Mouse model of unilateral left renal IRI with contralateral kidney enucleation, Ovariectomy in female mice, and a human embryonic kidney (HEK) cell model of hypoxia-reoxygenation were used to study how estrogen affects the sexual dimorphism of renal IRI through SIRT3 in vitro and in vivo, respectively. Here, we demonstrate differential expression of renal SIRT3 may induce sexual dimorphism in IRI using the renal IRI model. Higher SIRT3 level in female mice was associated with E2-induced protection of renal tubular epithelium, reduced mitochondrial reactive oxygen species (ROS), and IRI resistance. In hypoxia-reoxygenated HEK cells, SIRT3 knockdown increased oxidative stress, shifted the interconnected mitochondrial network toward fission, exacerbated hypoxia/reoxygenation-induced endoplasmic reticulum stress (ERS), and abolished the protective effects of E2 on IRI. Mechanistically, the SIRT3 level is E2-dependent and that E2 increases the SIRT3 protein level via estrogen receptor. SIRT3 targeted an i-AAA protease, yeast mitochondrial AAA metalloprotease (YME1L1), and hydrolyzed long optic atrophy 1 (L-OPA) to short-OPA1 (S-OPA1) by deacetylating YME1L1, regulating mitochondrial dynamics toward fusion to reduce oxidative stress and ERS. These findings explored the mechanism by how estrogen alleviates renal IRI and providing a basis for potential therapeutic interventions targeting SIRT3.

Oxidative balance score and associations with dyslipidemia and mortality among US adults: A mortality follow-up study of a cross-sectional cohort

BACKGROUND

Oxidative stress has been implicated in the pathogenesis and progression of dyslipidemia. We aimed to investigate the association between the oxidative balance score, and dyslipidemia, as well as to assess the mortality risk associated with oxidative balance score in patients with dyslipidemia.

METHODS

We performed a mortality follow-up study of a cross-sectional cohort of 26,118 adults from the National Health and Nutrition Examination Survey 1999-2018. The total oxidative balance score was calculated by 16 dietary nutrients (dietary oxidative balance score) and four lifestyle factors (lifestyle oxidative balance score). Weighted Cox proportional hazard model was applied to determine the relationship between oxidative balance score and all-cause or cardiovascular disease (CVD) mortality within the dyslipidemia group.

RESULTS

During a median follow-up of 118 months, 2448 all-cause deaths (766 CVD-related) occurred. A significant negative correlation was observed between total oxidative balance score, dietary oxidative balance score, lifestyle oxidative balance score, and dyslipidemia. The multivariable-adjusted odds ratios and 95% CIs for dyslipidemia were 0.86 (0.77-0.97), 0.80 (0.72-0.91), and 0.63 (0.56-0.70), respectively, when comparing the second, third, and fourth quartiles of total oxidative balance score to the reference lowest quartile (P for trend <0.0001). Increasing total oxidative balance score was inversely associated with all-cause (hazard ratio [HR] = 0.98, 95% CI 0.98-0.99) and CVD-specific mortality (HR = 0.98, 95% CI 0.97-0.99) in participants with dyslipidemia.

CONCLUSIONS

Oxidative balance score is inversely associated with dyslipidemia and linked to all-cause and CVD-related mortality, highlighting the potentially protective role of an antioxidant-rich diet against dyslipidemia.

Causal relationships between vitamin E and multiple kidney diseases: evidence from trans-ethnic Mendelian randomization study

PURPOSE

The association between vitamin E and the risk of kidney disease is well documented in observational studies, but the role of vitamin E in kidney disease remain inconclusive. Here, we evaluated the causal effect of vitamin E on the risk of multiple kidney diseases, including chronic kidney disease, membranous nephropathy, diabetic nephropathy, IgA nephropathy, and dialysis.

METHODS

We conducted a two-sample Mendelian randomization analysis from large-scale trans-ancestry genome-wide association studies to determine whether there was a significant causal relationship between vitamin E and multiple kidney diseases in European, American, and Asian ancestry. Instrumental genetic variants associated with vitamin E were selected, and summary statistic-based methods of inverse variance weighted, MR Egger, weighted median, simple mode, and weighted mode methods were conducted. Pleiotropy and sensitivity were assessed.

RESULTS

We obtained 87 instrumental genetic variants in European ancestry and found no causal relationship between vitamin E and chronic kidney disease, membranous nephropathy, diabetic nephropathy, IgA nephropathy, and dialysis with no heterogeneity and pleiotropy. We obtained 18 instrumental genetic variants in Asian ancestry and vitamin E had no causal relationship with membranous nephropathy, diabetic nephropathy, and IgA nephropathy with no heterogeneity and pleiotropy. In African ancestry, 25 instrumental genetic variants were obtained and no causal relationship was identified with no heterogeneity and pleiotropy.

CONCLUSION

Our study first suggested plausible non-causal associations between vitamin E and multiple kidney diseases among different ancestry.

Neonatal hyperoxia exposure leads to developmental programming of cardiovascular and renal disease in adult rats

Premature infants are often exposed to hyperoxia. However, there is limited data regarding the mechanistic underpinnings linking neonatal hyperoxia exposure and its contribution to cardio-renal dysfunction in adults born preterm. Our objective was to determine whether neonatal hyperoxia induces systemic vascular stiffness and cardio-renal dysfunction in adulthood. Newborn rats were randomly assigned to room air (RA) or hyperoxia (85% O2) from postnatal day 1 to 14, then recovered in RA until 1 year of life. Arterial stiffness, cardio-renal histomorphometry, and fibrosis in the aorta, heart, and kidney were assessed. RNA-sequencing (RNA-seq) of the aorta and kidney was also done. Adult rats exposed to neonatal hyperoxia had increased aortic and mesenteric artery stiffness as demonstrated by wire and pressure myography. They also had cardiomyocyte hypertrophy, glomerulomegaly, and tubular injury. Hyperoxia exposure altered the transcriptome profile associated with fibrosis and matrix remodeling in the aorta and kidney. There was also increased TGF-β1 levels and fibrosis in the aorta, left ventricle, and kidney. In conclusion, neonatal hyperoxia exposure was associated with systemic vascular and cardio-renal alterations in 1-year-old rats. Further studies to determine how targeted therapies could reprogram cardio-renal injury after neonatal hyperoxia exposure are indicated.

Aerobic training increases renal antioxidant defence and reduces angiotensin II levels, mitigating the high mortality in SHR-STZ model

OBJECTVE

The purpose of the research was to investigate the effects of aerobic training on renal function, oxidative stress, intrarenal renin-angiotensin system, and mortality of hypertensive and diabetic (SHR-STZ) rats.

MATERIALS AND METHODS

Blood pressure, creatinine, urea levels, urinary glucose, urine volume, and protein excretion were reduced in trained SHR-STZ rats.

RESULTS

Aerobic training not only attenuated oxidative stress but also elevated the activity of antioxidant enzymes in the kid'ney of SHR-STZ rats. Training increased intrarenal levels of angiotensin-converting enzymes (ACE and ACE2) as well as the neprilysin (NEP) activity, along with decreased intrarenal angiotensin II (Ang II) levels. Aerobic training significantly improved the survival of STZ-SHR rats.

CONCLUSION

The protective role of aerobic training was associated with improvements in the renal antioxidative capacity, reduced urinary protein excretion along with reduced intrarenal Ang II and increased NEP activity. These findings might reflect a better survival under the combined pathological conditions, hypertension, and diabetes.

The key role of altered tubule cell lipid metabolism in kidney disease development

Kidney epithelial cells have very high energy requirements, which are largely met by fatty acid oxidation. Complex changes in lipid metabolism are observed in patients with kidney disease. Defects in fatty acid oxidation and increased lipid uptake, especially in the context of hyperlipidemia and proteinuria, contribute to this excess lipid build-up and exacerbate kidney disease development. Recent studies have also highlighted the role of increased de novo lipogenesis in kidney fibrosis. The defect in fatty acid oxidation causes energy starvation. Increased lipid uptake, synthesis, and lower fatty acid oxidation can cause toxic lipid build-up, reactive oxygen species generation, and mitochondrial damage. A better understanding of these metabolic processes may open new treatment avenues for kidney diseases by targeting lipid metabolism.

Potential role of molecular hydrogen therapy on oxidative stress and redox signaling in chronic kidney disease

Oxidative stress plays a key role in chronic kidney disease (CKD) development and progression, inducing kidney cell damage, inflammation, and fibrosis. However, effective therapeutic interventions to slow down CKD advancement are currently lacking. The multifaceted pharmacological effects of molecular hydrogen (H2) have made it a promising therapeutic avenue. H2 is capable of capturing harmful •OH and ONOO- while maintaining the crucial reactive oxygen species (ROS) involved in cellular signaling. The NRF2-KEAP1 system, which manages cell redox balance, could be used to treat CKD. H2 activates this pathway, fortifying antioxidant defenses and scavenging ROS to counteract oxidative stress. H2 can improve NRF2 signaling by using the Wnt/β-catenin pathway and indirectly activate NRF2-KEAP1 in mitochondria. Additionally, H2 modulates NF-κB activity by regulating cellular redox status, inhibiting MAPK pathways, and maintaining Trx levels. Treatment with H2 also attenuates HIF signaling by neutralizing ROS while indirectly bolstering HIF-1α function. Furthermore, H2 affects FOXO factors and enhances the activity of antioxidant enzymes. Despite the encouraging results of bench studies, clinical trials are still limited and require further investigation. The focus of this review is on hydrogen's role in treating renal diseases, with a specific focus on oxidative stress and redox signaling regulation, and it discusses its potential clinical applications.

Protective effects of pioglitazone in renal ischemia-reperfusion injury (RIRI): focus on oxidative stress and inflammation

BACKGROUND

Renal ischemia-reperfusion injury (RIRI) is a critical phenomenon that compromises renal function and is the most serious health concern related to acute kidney injury (AKI). Pioglitazone (Pio) is a known agonist of peroxisome proliferator-activated receptor-gamma (PPAR-γ). PPAR-γ is a nuclear receptor that regulates genes involved in inflammation, metabolism, and cellular differentiation. Activation of PPAR-γ is associated with antiinflammatory and antioxidant effects, which are relevant to the pathophysiology of RIRI. This study aimed to investigate the protective effects of Pio in RIRI, focusing on oxidative stress and inflammation.

METHODS

We conducted a comprehensive literature search using electronic databases, including PubMed, ScienceDirect, Web of Science, Scopus, and Google Scholar.

RESULTS

The results of this study demonstrated that Pio has antioxidant, anti-inflammatory, and anti-apoptotic activities that counteract the consequences of RIRI. The study also discussed the underlying mechanisms, including the modulation of various pathways such as TNF-α, NF-κB signaling systems, STAT3 pathway, KIM-1 and NGAL pathways, AMPK phosphorylation, and autophagy flux. Additionally, the study presented a summary of various animal studies that support the potential protective effects of Pio in RIRI.

CONCLUSION

Our findings suggest that Pio could protect the kidneys from RIRI by improving antioxidant capacity and decreasing inflammation. Therefore, these findings support the potential of Pio as a therapeutic strategy for preventing RIRI in different clinical conditions.

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.

Nutritional Strategies against Diabetic Nephropathy: Insights from Animal Studies and Human Trials

Diabetic nephropathy (DN), defined as continuously elevated urinary albumin and a diminished estimated glomerular filtration rate, is a serious complication of both type 1 diabetes and type 2 diabetes and is the main cause of end-stage kidney disease. Patients with end-stage renal disease require chronic kidney dialysis and/or a kidney transplantation. Research highlights the role of diet in modulating specific signaling pathways that are instrumental in the progression of DN. Nutrient-sensitive pathways, affected by nutritional compounds and dietary components, offer a novel perspective on the management of DN by influencing inflammation, oxidative stress, and nutrient metabolism. Animal models have identified signaling pathways related to glucose metabolism, inflammation responses, autophagy, and lipid metabolism, while human population studies have contributed to the clinical significance of designing medical and nutritional therapies to attenuate DN progression. Here, we will update recent progress in research into the renoprotective or therapeutic effects of nutritional compounds, and potential nutrition-modulated pathways.

Anticancer Therapies Based on Oxidative Damage: Lycium barbarum Inhibits the Proliferation of MCF-7 Cells by Activating Pyroptosis through Endoplasmic Reticulum Stress

Lycium barbarum, commonly recognized as goji berry or wolfberry, is highly appreciated not only for its organoleptic and nutritional properties but also as an important source of bioactive compounds such as polysaccharides, carotenoids, phenolics, and various other non-nutritive compounds. These constituents give it a multitude of health benefits, including antioxidant, anti-inflammatory, and anticancer properties. However, the precise biochemical mechanisms responsible for its anticancer effects remain unclear, and the comprehensive composition of goji berry extracts is often insufficiently explored. This study aimed to investigate the biochemical pathways modulated in breast cancer cells by an ethanolic extract of Lycium barbarum fruit (LBE). Following metabolomic profiling using UHPLC-HRMS/MS, we assessed the antitumoral properties of LBE on different breast cancer cell lines. This investigation revealed that LBE exhibited cytotoxic effects, inducing a pro-oxidant effect that triggered pyroptosis activation through endoplasmic reticulum (ER) stress and subsequent activation of the P-IRE1α/XBP1/NLRP3 axis in MCF-7 cells. In addition, LBE did not display cytotoxicity toward healthy human cells but demonstrated antioxidant properties by neutralizing ROS generated by doxorubicin. These findings underscore the potential of LBE as a highly promising natural extract in cancer therapy.

HOXD10 attenuates renal fibrosis by inhibiting NOX4-induced ferroptosis

In chronic kidney disease (CKD), renal fibrosis is an unavoidable result of various manifestations. However, its pathogenesis is not yet fully understood. Here, we revealed the novel role of Homeobox D10 (HOXD10) in CKD-related fibrosis. HOXD10 expression was downregulated in CKD-related in vitro and in vivo fibrosis models. UUO model mice were administered adeno-associated virus (AAV) containing HOXD10, and HOXD10 overexpression plasmids were introduced into human proximal tubular epithelial cells induced by TGF-β1. The levels of iron, reactive oxygen species (ROS), lipid ROS, the oxidized glutathione/total glutathione (GSSG/GSH) ratio, malonaldehyde (MDA), and superoxide dismutase (SOD) were determined using respective assay kits. Treatment with AAV-HOXD10 significantly attenuated fibrosis and renal dysfunction in UUO model mice by inhibiting NOX4 transcription, ferroptosis pathway activation, and oxidative stress. High levels of NOX4 transcription, ferroptosis pathway activation and profibrotic gene expression induced by TGF-β1/erastin (a ferroptosis agonist) were abrogated by HOXD10 overexpression in HK-2 cells. Moreover, bisulfite sequencing PCR result determined that HOXD10 showed a hypermethylated level in TGF-β1-treated HK-2 cells. The binding of HOXD10 to the NOX4 promoter was confirmed by chromatin immunoprecipitation (ChIP) analysis and dual-luciferase reporter assays. Targeting HOXD10 may represent an innovative therapeutic strategy for fibrosis treatment in CKD.

Role of Uremic Toxins, Oxidative Stress, and Renal Fibrosis in Chronic Kidney Disease

Affecting millions of people worldwide, chronic kidney disease is a serious medical problem. It results in a decrease in glomerular filtration rate below 60 mL/min/1.73 m, albuminuria, abnormalities in urine sediment and pathologies detected by imaging studies lasting a minimum of 3 months. Patients with CKD develop uremia, and as a result of the accumulation of uremic toxins in the body, patients can be expected to suffer from a number of medical consequences such as progression of CKD with renal fibrosis, development of atherosclerosis or increased incidence of cardiovascular events. Another key element in the pathogenesis of CKD is oxidative stress, resulting from an imbalance between the production of antioxidants and the production of reactive oxygen species. Oxidative stress contributes to damage to cellular proteins, lipids and DNA and increases inflammation, perpetuating kidney dysfunction. Additionally, renal fibrogenesis involving the accumulation of fibrous tissue in the kidneys occurs. In our review, we also included examples of forms of therapy for CKD. To improve the condition of CKD patients, pharmacotherapy can be used, as described in our review. Among the drugs that improve the prognosis of patients with CKD, we can include: GLP-1 analogues, SGLT2 inhibitors, Finerenone monoclonal antibody-Canakinumab and Sacubitril/Valsartan.

WWP2 Regulates Renal Fibrosis and the Metabolic Reprogramming of Profibrotic Myofibroblasts

Key Points

WWP2 expression is elevated in the tubulointerstitium of fibrotic kidneys and contributes to CKD pathogenesis and progression. WWP2 uncouples the profibrotic activation and cell proliferation in renal myofibroblasts. WWP2 controls mitochondrial respiration in renal myofibroblasts through the metabolic regulator peroxisome proliferator-activated receptor gamma coactivator 1-alpha.

Background

Renal fibrosis is a common pathologic end point in CKD that is challenging to reverse, and myofibroblasts are responsible for the accumulation of a fibrillar collagen–rich extracellular matrix. Recent studies have unveiled myofibroblasts' diversity in proliferative and fibrotic characteristics, which are linked to different metabolic states. We previously demonstrated the regulation of extracellular matrix genes and tissue fibrosis by WWP2, a multifunctional E3 ubiquitin–protein ligase. Here, we investigate WWP2 in renal fibrosis and in the metabolic reprograming of myofibroblasts in CKD.

Methods

We used kidney samples from patients with CKD and WWP2 -null kidney disease mice models and leveraged single-cell RNA sequencing analysis to detail the cell-specific regulation of WWP2 in fibrotic kidneys. Experiments in primary cultured myofibroblasts by bulk-RNA sequencing, chromatin immunoprecipitation sequencing, metabolomics, and cellular metabolism assays were used to study the metabolic regulation of WWP2 and its downstream signaling.

Results

The tubulointerstitial expression of WWP2 was associated with fibrotic progression in patients with CKD and in murine kidney disease models. WWP2 deficiency promoted myofibroblast proliferation and halted profibrotic activation, reducing the severity of renal fibrosis in vivo . In renal myofibroblasts, WWP2 deficiency increased fatty acid oxidation and activated the pentose phosphate pathway, boosting mitochondrial respiration at the expense of glycolysis. WWP2 suppressed the transcription of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), a metabolic mediator of fibrotic response, and pharmacologic inhibition of PGC-1α partially abrogated the protective effects of WWP2 deficiency on myofibroblasts.

Conclusions

WWP2 regulates the metabolic reprogramming of profibrotic myofibroblasts by a WWP2-PGC-1α axis, and WWP2 deficiency protects against renal fibrosis in CKD.

The role of mitochondrial dysfunction in kidney injury and disease

Mitochondria are the main sites of aerobic respiration in the cell and mainly provide energy for the organism, and play key roles in adenosine triphosphate (ATP) synthesis, metabolic regulation, and cell differentiation and death. Mitochondrial dysfunction has been identified as a contributing factor to a variety of diseases. The kidney is rich in mitochondria to meet energy needs, and stable mitochondrial structure and function are essential for normal kidney function. Recently, many studies have shown a link between mitochondrial dysfunction and kidney disease, maintaining mitochondrial homeostasis has become an important target for kidney therapy. In this review, we integrate the role of mitochondrial dysfunction in different kidney diseases, and specifically elaborate the mechanism of mitochondrial reactive oxygen species (mtROS), autophagy and ferroptosis involved in the occurrence and development of kidney diseases, providing insights for improved treatment of kidney diseases.

Renoprotective effects of Schoenoplectus tabernaemontani rhizomes aqueous extracts against Adriamycin-induced nephropathy in rats

In recent years, chronic kidney disease (CKD) has emerged as an increasingly significant issue due to the growing prevalence and high treatment costs. While recorded the positive diuretic effect of Schoenoplectus tabernaemontani, there is a lack of reports on its efficacy in treating CKD. The pharmacological effects and mechanisms of Schoenoplectus tabernaemontani rhizomes aqueous extracts (STE) in CKD were investigated by inducing a rodent model of CKD via injection of Adriamycin (ADR; 7.5 mg/kg) into the tail vein of Wistar rats. In summary, our findings suggest that STE has a beneficial effect on anti-renal fibrosis and can reverse ADR-induced renal injury by suppressing oxidative stress and inflammation. Therefore, STE holds promising potential as a treatment option for CKD.

Association between composite dietary antioxidant index and kidney stone prevalence in adults: data from National Health and Nutrition Examination Survey (NHANES, 2007-2018)

Background

The high prevalence of kidney stones in adults worldwide has prompted research into potential interventions, one of which involves exploring the consumption of antioxidants that may confer protective effects. However, the relationship between the composite dietary antioxidant index (CDAI), a crucial measure used to assess an individual's overall antioxidant capacity from daily dietary intake, and kidney stones remains unclear. Therefore, we conducted cross-sectional analysis to examine the association between CDAI and kidney stone prevalence.

Methods

The analysis was conducted utilizing data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2018. Antioxidant intake was derived from two 24-h dietary recalls surveys, while CDAI, a comprehensive measure that includes antioxidants like vitamins A, C, and E, zinc, selenium, and carotenoids, was calculated. Multivariate logistic regression and restricted cubic spline (RCS) regression were utilized to examine the association between CDAI and the prevalence of kidney stones.

Results

The study included a total of 28,516 participants, with 2,748 individuals having a history of kidney stones. The median of CDAI was -0.01 (-2.02, 2.37). Individuals in the fourth quartile of CDAI exhibited a significantly lower prevalence of kidney stones compared to those in the first quartile (Odds Ratio [OR] = 0.769 [0.633-0.935]), even after adjusting for potential confounding factors (including age, sex, race, education level, poverty income ratio, smoking status, drinking status, body mass index (BMI), energy intake levels, physical activity level, serum calcium concentration, estimated glomerular filtration rate (eGFR), hypertension, diabetes and supplement use). The RCS analysis revealed a non-linear relationship between CDAI and kidney stone prevalence, with inflection points identified at 0.06 (p for non-linearity = 0.039). Subgroup analysis demonstrated consistent CDAI-kidney stone prevalence associations across all subsets. Furthermore, a significant inverse correlation was observed between CDAI and inflammatory markers.

Conclusion

This study provides evidence supporting a reciprocal correlation between adult dietary antioxidant intake, as measured by CDAI, and kidney stone prevalence. These findings emphasize the potential benefits of consuming dietary antioxidants in lowering the risk of kidney stone formation.

Modulation of Sirtuin 3 by N-Acetylcysteine Preserves Mitochondrial Oxidative Phosphorylation and Restores Bisphenol A-Induced Kidney Damage in High-Fat-Diet-Fed Rats

Bisphenol A (BPA) and high-fat diets (HFD) are known to adversely affect the kidneys. However, the combined effects of both cases on kidney health and the potential benefits of N-acetylcysteine (NAC) in mitigating these effects have not been investigated. To explore these aspects, male Wistar rats were fed with HFD and allocated to receive a vehicle or BPA. At week twelve, the BPA-exposed rats were subdivided to receive a vehicle or NAC along with BPA until week sixteen. Rats fed HFD and exposed to BPA showed renal dysfunction and structural abnormalities, oxidative stress, inflammation, and mitochondrial dysfunction, with alterations in key proteins related to mitochondrial oxidative phosphorylation (OXPHOS), bioenergetics, oxidative balance, dynamics, apoptosis, and inflammation. Treatment with NAC for 4 weeks significantly improved these conditions. The findings suggest that NAC is beneficial in protecting renal deterioration brought on by prolonged exposure to BPA in combination with HFD, and modulation of sirtuin 3 (SIRT3) signaling by NAC appears to play a key role in the preservation of homeostasis and integrity within the mitochondria by enhancing OXPHOS activity, maintaining redox balance, and reducing inflammation. This study provides valuable insights into potential therapeutic strategies for preserving kidney health in the face of environmental and dietary challenges.

Role and Mechanism of Growth Differentiation Factor 15 in Chronic Kidney Disease

GDF-15 is an essential member of the transforming growth factor-beta superfamily. Its functions mainly involve in tissue injury, inflammation, fibrosis, regulation of appetite and weight, development of tumor, and cardiovascular disease. GDF-15 is involved in various signaling pathways, such as MAPK pathway, PI3K/AKT pathway, STAT3 pathway, RET pathway, and SMAD pathway. In addition, several factors such as p53, ROS, and TNF-α participate the regulation of GDF-15. However, the specific mechanism of these factors regulating GDF-15 is still unclear and more research is needed to explore them. GDF-15 mainly improves the function of kidneys in CKD and plays an important role in the prediction of CKD progression and cardiovascular complications. In addition, the role of GDF-15 in the kidney may be related to the SMAD and MAPK pathways. However, the specific mechanism of these pathways remains unclear. Accordingly, more research on the specific mechanism of GDF-15 affecting kidney disease is needed in the future. In conclusion, GDF-15 may be a therapeutic target for kidney disease.

Box A of HMGB1 Maintains the DNA Gap and Prevents DDR-induced Kidney Injury in D-galactose Induction Rats

BACKGROUND/AIM

Disability and mortality rates for renal failure are still increasing. DNA damage and oxidative stress intoxication from body metabolism, high blood glucose, or the environment cause significant kidney damage. Recently, we reported that Box A of HMGB1 (Box A) acts as molecular scissors, producing DNA gaps that prevent DNA damage in kidney cell lines and ultimately reverse aging phenotypes in aging rat models. The present study aimed to demonstrate the potency of Box A in preventing D-galactose (D-gal)-induced kidney injury.

MATERIALS AND METHODS

A Box A expression plasmid was constructed and administered to a rat model. D-gal was injected subcutaneously for eight weeks. Serum was collected to study renal function, and white blood cells were collected for DNA gap measurement. Kidney tissue was also collected for γ-H2AX and NF-κB immunostaining; Senescence-associated (SA)-beta-gal staining; and analysis of the mRNA expression of p16INK4A, TNF-α, and IL-6. Moreover, histopathology analysis was performed using hematoxylin & eosin and Masson trichome staining.

RESULTS

Pretreatment with Box A administration prevented the reduction of DNA gaps and the consequences of the DNA damage response, which include elevated serum creatinine; high serum BUN; an increased positive SA-beta-gal staining area; overexpression of p16INK4A, NF-κB and senescence-associated secretory phenotype molecules, including IL-6, TNF-α; and histological alterations, including tubular dilation and collagen accumulation.

CONCLUSION

Box A effectively prevents DNA gap reduction and all D-gal-induced kidney pathological changes at the molecular, histological, and physiological levels. Therefore, Box A administration is a promising novel therapeutic strategy to prevent DNA-damaging agent-induced kidney failure.

Integrative transcriptomic and proteomic profile revealed inhibition of oxidative phosphorylation and peroxisomes during renal interstitial fibrosis

Effective therapies of chronic kidney disease (CKD) are lacking due to the unclear molecular pathogenesis. Previous single omics-studies have described potential molecular regulation mechanism of CKD only at the level of transcription or translation. Therefore, this study generated an integrated transcriptomic and proteomic profile to provide deep insights into the continuous transcription-translation process during CKD. The comprehensive datasets identified 14,948 transcripts and 6423 proteins, 233 up-regulated and 364 down-regulated common differentially expressed genes of transcriptome and proteome were selected to further combined bioinformatics analysis. The obtained results revealed reactive oxygen species (ROS) metabolism and antioxidant system due to imbalance of mitochondria and peroxisomes were significantly repressed in CKD. Overall, this study presents a valuable multi-omics analysis that sheds light on the molecular mechanisms underlying CKD. SIGNIFICANCE: Chronic kidney disease (CKD) is a progressive and irreversible condition that results in abnormal kidney function and structure, and is ranked 18th among the leading causes of death globally, leading to a significant societal burden. Hence, there is an urgent need for research to detect new, sensitive, and specific biomarkers. Omics-based studies offer great potential to identify underlying disease mechanisms, aid in clinical diagnosis, and develop novel treatment strategies for CKD. Previous studies have mainly focused on the regulation of gene expression or protein synthesis in CKD, thereby compelling us to conduct a meticulous analysis of transcriptomic and proteomic data from the UUO mouse model. Here, we have performed a unified analysis of CKD model by integrating transcriptomes and protein suites for the first time. Our study contributes to a deeper understanding of the pathogenesis of CKD and provides a basis for subsequent disease management and drug development.

Causal relationship between basal metabolic rate and kidney function: a bidirectional two-sample mendelian randomization study

Background

The relationship between basal metabolic rate (BMR) and Chronic kidney disease (CKD) remains unclear and controversial. In this study, we investigated the causal role of BMR in renal injury, and inversely, whether altered renal function causes changes in BMR.

Methods

In this two-sample mendelian randomization (MR) study, Genetic data were accessed from published genome-wide association studies (GWAS) for BMR ((n = 454,874) and indices of renal function, i.e. estimated glomerular filtration rate (eGFR) based on creatinine (n =1, 004, 040), CKD (n=480, 698), and blood urea nitrogen (BUN) (n =852, 678) in European. The inverse variance weighted (IVW) random-effects MR method serves as the main analysis, accompanied by several sensitivity MR analyses. We also performed a reverse MR to explore the causal effects of the above indices of renal function on the BMR.

Results

We found that genetically predicted BMR was negatively related to eGFR, (β= -0.032, P = 4.95*10-12). Similar results were obtained using the MR-Egger (β= -0.040, P = 0.002), weighted median (β= -0.04, P= 5.35×10-11) and weighted mode method (β= -0.05, P=9.92×10-7). Higher BMR had a causal effect on an increased risk of CKD (OR =1.36, 95% CI = 1.11-1.66, P =0.003). In reverse MR, lower eGFR was related to higher BMR (β= -0.64, P = 2.32×10-6, IVW analysis). Bidirectional MR supports no causal association was observed between BMR and BUN. Sensitivity analyses confirmed these findings, indicating the robustness of the results.

Conclusion

Genetically predicted high BMR is associated with impaired kidney function. Conversely, genetically predicted decreased eGFR is associated with higher BMR.

Oxidative Stress: A Culprit in the Progression of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the principal culprit behind chronic kidney disease (CKD), ultimately developing end-stage renal disease (ESRD) and necessitating costly dialysis or kidney transplantation. The limited therapeutic efficiency among individuals with DKD is a result of our finite understanding of its pathogenesis. DKD is the result of complex interactions between various factors. Oxidative stress is a fundamental factor that can establish a link between hyperglycemia and the vascular complications frequently encountered in diabetes, particularly DKD. It is crucial to recognize the essential and integral role of oxidative stress in the development of diabetic vascular complications, particularly DKD. Hyperglycemia is the primary culprit that can trigger an upsurge in the production of reactive oxygen species (ROS), ultimately sparking oxidative stress. The main endogenous sources of ROS include mitochondrial ROS production, NADPH oxidases (Nox), uncoupled endothelial nitric oxide synthase (eNOS), xanthine oxidase (XO), cytochrome P450 (CYP450), and lipoxygenase. Under persistent high glucose levels, immune cells, the complement system, advanced glycation end products (AGEs), protein kinase C (PKC), polyol pathway, and the hexosamine pathway are activated. Consequently, the oxidant-antioxidant balance within the body is disrupted, which triggers a series of reactions in various downstream pathways, including phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), transforming growth factor beta/p38-mitogen-activated protein kinase (TGF-β/p38-MAPK), nuclear factor kappa B (NF-κB), adenosine monophosphate-activated protein kinase (AMPK), and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling. The disease might persist even if strict glucose control is achieved, which can be attributed to epigenetic modifications. The treatment of DKD remains an unresolved issue. Therefore, reducing ROS is an intriguing therapeutic target. The clinical trials have shown that bardoxolone methyl, a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, blood glucose-lowering drugs, such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists can effectively slow down the progression of DKD by reducing oxidative stress. Other antioxidants, including vitamins, lipoic acid, Nox inhibitors, epigenetic regulators, and complement inhibitors, present a promising therapeutic option for the treatment of DKD. In this review, we conduct a thorough assessment of both preclinical studies and current findings from clinical studies that focus on targeted interventions aimed at manipulating these pathways. We aim to provide a comprehensive overview of the current state of research in this area and identify key areas for future exploration.

The preventive effect of Gastrodia elata Blume extract on vancomycin-induced acute kidney injury in rats

BACKGROUND

Gastrodia elata Blume (GEB), a traditional medicinal herb, has been reported to have pharmacological effect including protection against liver, neuron and kidney toxicity. However, explanation of its underlying mechanisms remains a great challenge. This study investigated the protective effects of GEB extract on vancomycin (VAN)-induced nephrotoxicity in rats and underlying mechanisms with emphasis on the anti-oxidative stress, anti-inflammation and anti-apoptosis. The male Sprague-Dawley rats were randomly divided three groups: control (CON) group, VAN group and GEB group with duration of 14 days.

RESULTS

The kidney weight and the serum levels of blood urea nitrogen and creatinine in the GEB group were lower than the VAN group. Histological analysis using hematoxylin & eosin and periodic acid Schiff staining revealed pathological changes of the VAN group. Immunohistochemical analysis revealed that the expression levels of N-acetyl-D-glucosaminidase, myeloperoxidase and tumor necrosis factor-alpha in the GEB group were decreased when compared with the VAN group. The number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells, phosphohistone and malondialdehyde levels were lower in the GEB group than VAN group. The levels of total glutathione in the GEB group were higher than the VAN group.

CONCLUSIONS

The findings of this study suggested that GEB extract prevents VAN-induced renal tissue damage through anti-oxidation, anti-inflammation and anti-apoptosis.

Wnt/β-catenin Pathway Aggravates Renal Fibrosis by Activating PUM2 Transcription to Repress YME1L-mediated Mitochondrial Homeostasis

Chronic kidney disease (CKD) affects more than 10% of people worldwide and is a leading cause of death. However, the pathogenesis of CKD remains elusive. The oxidative stress and mitochondrial membrane potential were detected using Enzyme-linked immunosorbent assay and JC-1 assay. Co-immunoprecipitation, dual-luciferase assay, chromatin IP, RNA IP and RNA pull-down were used to validate the interactions among genes. Exploiting a H2O2-induced fibrosis model in vitro, PUM2 expression was upregulated in Human kidney 2 cell (HK-2) cells, along with reduced cell viability, enhanced oxidative stress, impaired mitochondrial potential, and upregulated expressions of fibrosis-associated proteins. While PUM2 knockdown reversed the H2O2-induced injury in HK-2 cells. Mechanically, Wnt/β-catenin pathway activated PUM2 transcription via TCF4. It was further identified that Wnt/β-catenin pathway inhibited YME1L expression through PUM2-mediated destabilizing of its mRNA. PUM2 aggravated H2O2-induced oxidative stress, mitochondrial dysfunction, and renal fibrosis in HK-2 cell via suppressing YME1L expression. Our study revealed that Wnt/β-catenin aggravated renal fibrosis by activating PUM2 transcription to repress YME1L-mediated mitochondrial homeostasis, providing novel insights and potential therapeutic targets for the treatment of kidney fibrosis.

Novel biomarkers related to oxidative stress and immunity in chronic kidney disease

Introduction

The incidence of chronic kidney disease (CKD) has been increasing in recent years, gradually becoming a global health crisis. Due to limited treatment options, novel molecular pathways are urgently required to advance the treatment and diagnosis of CKD.

Materials and methods

The characteristics of differentially expressed genes (DEGs) in CKD patients were analyzed using Gene Expression Omnibus (GEO) database, and genes related to oxidative stress were retrieved from the Genecard database. Subsequently, a comprehensive approach was applied, including immune infiltration analysis, weighted gene co-expression network analysis (WGCNA) and protein-protein interaction (PPI) network analysis, to identify hub genes among differentially expressed immune-related oxidative stress genes (DEIOSGs). Validation of hub genes was performed using an external data set, and diagnostic potential capability was evaluated through receiver operating curve (ROC) analysis. In animal experiments, the expression of hub genes in CKD was confirmed by inducing a CKD model through a 5/6 nephrectomy procedure. Finally, the relationship between these hub genes and clinical characteristics were assessed using the Nephroseq v5 database.

Results

29 DEIOSGs were identified by comprehensive bioinformatics analysis. PPI analysis screened the hub genes NCF2, S100A9, and SELL. ROC analysis demonstrated excellent diagnostic efficacy. Further validation from other databases and animal experiments confirmed a substantial upregulation in the expression of hub genes in CKD. Additionally, clinical correlation analysis established a clear link between hub gene expression and renal function deterioration.

Conclusions

Our study confirms NCF2, S100A9, and SELL as diagnostic biomarkers associated with immune response and oxidative stress in CKD, suggesting their potential as novel targets for CKD diagnosis and treatment.

Can blood morphology, oxidative stress, and cholinesterase activity determine health status of pigeon Columba livia f. urbana?

Environmental studies in Northern Poland are example of the functioning of ecophysiological relationships under anthropogenic impact. The aim of our studies was to investigate sex-dependent effects on the alterations in the concentration of chemical elements in soil samples collected from habitats of feral pigeon Columba livia f. urbana from Northern Poland, as well as feathers, biomarkers of oxidative stress, antioxidant defense, and total cholinesterase activity in tissues (liver, kidney, brain). Concentration of Si, Zn, and Pb in feathers of pigeons was significant. The levels of Si and Zn were higher in feathers of females from non-polluted, while higher Pb levels were found only in females from polluted areas (p = 0.000). This was confirmed by MANOVA of biomarkers of antioxidant defense, elements concentration, and revealing the order of effects: tissue type > environment > sex. Erythrocytes of males living in polluted areas were more fragile to hemolytic agents resulting in a higher percentage of hemolyzed erythrocytes. The effects of polluted environment on the level of carbonyl derivatives of oxidatively modified proteins compared to the effects of sex were more pronounced in the case of kidney (p = 0.000) and hepatic tissues (p = 0.000). Polluted areas were associated with significant increase in SOD activity in the brain and hepatic tissues of pigeons (p = 0.000). Health status of feral pigeons is significantly different in conditions of environmental destabilization.

Chronic kidney disease in a murine model of non-alcoholic steatohepatitis (NASH)

Clinical studies suggest that non-alcoholic steatohepatitis (NASH) is an independent risk factor for chronic kidney disease (CKD), but causality and mechanisms linking these two major diseases are lacking. To assess whether NASH can induce CKD, we have characterized kidney function, histological features, transcriptomic and lipidomic profiles in a well-validated murine NASH model. Mice with NASH progressively developed significant podocyte foot process effacement, proteinuria, glomerulosclerosis, tubular epithelial cell injury, lipid accumulation, and interstitial fibrosis. The progression of kidney fibrosis paralleled the severity of the histologic NASH-activity score. Significantly, we confirmed the causal link between NASH and CKD by orthotopic liver transplantation, which attenuated proteinuria, kidney dysfunction, and fibrosis compared with control sham operated mice. Transcriptomic analysis of mouse kidney cortices revealed differentially expressed genes that were highly enriched in mitochondrial dysfunction, lipid metabolic process, and insulin signaling pathways in NASH-induced CKD. Lipidomic analysis of kidney cortices further revealed that phospholipids and sphingolipids were the most significantly changed lipid species. Notably, we found similar kidney histological changes in human NASH and CKD. Thus, our results confirm a causative role of NASH in the development of CKD, reveal potential pathophysiologic mechanisms of NASH-induced kidney injury, and established a valuable model to study the pathogenesis of NASH-associated CKD. This is an important feature of fatty liver disease that has been largely overlooked but has clinical and prognostic importance.

Study on the chronic inflammatory injury caused by Ageratina adenophora on goat liver using metabolomics

Ageratina adenophora (A. adenophora) is an invasive plant that is harmful to animals. The plants toxic effects on the liver have been studied in detail, however, the inflammation aspects of the hepatotoxicity are rarely discussed in literature. Therefore, in this study, we investigated the level of inflammation and the associated changes in liver metabolism caused by A. adenophora ingestion. Goat were fed with A. adenophora powder which accounts for 40% of the forage for 90 d. After the feeding period, the liver tissues were collected and the level of inflammation was detected using H & E staining and the changes in metabolites by LC-MS/MS. The results indicated that A. adenophora changes the liver metabolites, The test group shown 153 different metabolites in liver of which 71 were upregulated and 82 down regulated. We also found two differential metabolic pathways: neuroactive ligand-receptor interaction and pyrimidine metabolism. The changes in the pathway suggested an association with inflammation and with pathological processes such as oxidative stress and apoptosis. In addition, we observed an increase in the levels of serum liver function indexes (AST and ALT), indicating the liver injury. Furthermore, inflammatory cell infiltration and cell degeneration were observed in histopathological sections. In conclusion, this study reveals that A. adenophora causes chronic inflammation and upregulate metabolites related to inflammation in the liver. The study complements the research content of A. adenophora hepatotoxicity and provides a basis for further research by analyzing changes in the liver metabolites.

Cardiac and Renal Fibrosis, the Silent Killer in the Cardiovascular Continuum: An Up-to-Date

Cardiovascular disease (CVD) and chronic kidney disease (CKD) often coexist and have a major impact on patient prognosis. Organ fibrosis plays a significant role in the pathogenesis of cardio-renal syndrome (CRS), explaining the high incidence of heart failure and sudden cardiac death in these patients. Various mediators and mechanisms have been proposed as contributors to the alteration of fibroblasts and collagen turnover, varying from hemodynamic changes to the activation of the renin-angiotensin system, involvement of FGF 23, and Klotho protein or collagen deposition. A better understanding of all the mechanisms involved has prompted the search for alternative therapeutic targets, such as novel inhibitors of the renin-angiotensin-aldosterone system (RAAS), serelaxin, and neutralizing interleukin-11 (IL-11) antibodies. This review focuses on the molecular mechanisms of cardiac and renal fibrosis in the CKD and heart failure (HF) population and highlights the therapeutic alternatives designed to target the responsible pathways.

Protective effects of l-carnitine on isoprenaline -induced heart and kidney dysfunctions: Modulation of inflammation and oxidative stress-related gene expression in rats

The aim of this study was to evaluate the effect of l-carnitine (L-CAR) treatment on isoprenaline (ISO) administered kidney and heart impairment in male Long Evans rats. Four groups of rats were engaged in this study such as control, ISO, control + L-CAR, and ISO + L-CAR, where n = 6 in each group. The rats were also provided with chow food and water ad libitum. At the end of the study, all rats were sacrificed, and blood and tissue samples were collected for bio-chemical analysis. Oxidative stress parameters and antioxidant enzyme activities were determined in plasma and tissues. Antioxidant and inflammatory genes expression were analyzed in the kidney cortex, and histopathological studies of kidney tissues were performed. This study showed that creatinine and uric acid in plasma were significantly increased in ISO-administered rats. l-carnitine treatment lowered the uric acid and creatinine level. ISO-administered rats showed increased lipid peroxidation and declined levels of antioxidant enzymes activities in kidneys and heart. l-carnitine treatment restored antioxidant enzymes activities and protect against oxidative stress in kidney and heart. This effect is correlated with the restoration of Nrf-2-HO-1 genes expression followed by increased SOD and catalase genes expression in the kidney. l-carnitine treatment also prevented the TNF-α, IL-6, and NF-кB expression in kidneys of ISO administered rats. Histopathology staining showed that l-carnitine treatment prevented kidney damage and collagen deposition in ISO administered rats. The result of this study exhibited that l-carnitine treatment reduced oxidative stress and increased antioxidant enzyme activities by enhancing antioxidant genes expression in ISO administered rats.

Effect of 7-ketocholesterol incorporation on substrate binding affinity and turnover rate of the organic cation transporter 2 (OCT2)

The organic cation transporter 2 (OCT2) is pivotal in the renal elimination of several positively charged molecules. OCT2 mode of transport is profoundly influenced by the level of membrane cholesterol. The aim of this study was to investigate the effect of oxidized cholesterol on OCT2 transport activity in human embryonic kidney 293 cells stably transfected with OCT2 (OCT2-HEK293) and in primary renal proximal tubular epithelial cells (RPTEC). Cholesterol was exchanged with 7-ketocholesterol, the main product of cholesterol auto-oxidation, by exposing cells to sterol-saturated methyl-β-cyclodextrin (mβcd). After a 30 min-exposure, approximately 50% of the endogenous cholesterol was replaced by 7-ketocholesterol without significant changes in total sterol level. In the presence of 7-ketocholesterol, [3H]1-methyl-4-phenylpyridinium (MPP+) uptake was significantly reduced in both cell lines. 7-ketocholesterol incorporation did not affect lipid raft integrity, nor OCT2 surface expression and spatial organization. The inhibitory effect of 7-ketocholesterol on MPP+ uptake was abolished by the presence of MPP+ in the trans-compartment. In the presence of 7-ketocholesterol, both Kt and Vmax of MPP+ influx decreased. Molecular docking using OCT2 structure in outward occluded conformation showed overlapping poses and similar binding energies between cholesterol and 7-ketocholesterol. The thermal stability of OCT2 was not changed when cholesterol was replaced with 7-ketocholesterol. We conclude that 7-ketocholesterol confers a higher rigidity to the carrier by reducing its conformational entropy, arguably as a result of changes in plasma membrane physical properties, thereby facilitating the achievement of a higher affinity state at the expense of the mobility and overall cycling rate of the transporter.

Oxidative stress and the role of redox signalling in chronic kidney disease

Chronic kidney disease (CKD) is a major public health concern, underscoring a need to identify pathogenic mechanisms and potential therapeutic targets. Reactive oxygen species (ROS) are derivatives of oxygen molecules that are generated during aerobic metabolism and are involved in a variety of cellular functions that are governed by redox conditions. Low levels of ROS are required for diverse processes, including intracellular signal transduction, metabolism, immune and hypoxic responses, and transcriptional regulation. However, excess ROS can be pathological, and contribute to the development and progression of chronic diseases. Despite evidence linking elevated levels of ROS to CKD development and progression, the use of low-molecular-weight antioxidants to remove ROS has not been successful in preventing or slowing disease progression. More recent advances have enabled evaluation of the molecular interactions between specific ROS and their targets in redox signalling pathways. Such studies may pave the way for the development of sophisticated treatments that allow the selective control of specific ROS-mediated signalling pathways.

The role of matrix metalloproteinase 9 in fibrosis diseases and its molecular mechanisms

Fibrosis is a process of tissue repair that results in the slow creation of scar tissue to replace healthy tissue and can affect any tissue or organ. Its primary feature is the massive deposition of extracellular matrix (mainly collagen), eventually leading to tissue dysfunction and organ failure. The progression of fibrotic diseases has put a significant strain on global health and the economy, and as a result, there is an urgent need to find some new therapies. Previous studies have identified that inflammation, oxidative stress, some cytokines, and remodeling play a crucial role in fibrotic diseases and are essential avenues for treating fibrotic diseases. Among them, matrix metalloproteinases (MMPs) are considered the main targets for the treatment of fibrotic diseases since they are the primary driver involved in ECM degradation, and tissue inhibitors of metalloproteinases (TIMPs) are natural endogenous inhibitors of MMPs. Through previous studies, we found that MMP-9 is an essential target for treating fibrotic diseases. However, it is worth noting that MMP-9 plays a bidirectional regulatory role in different fibrotic diseases or different stages of the same fibrotic disease. Previously identified MMP-9 inhibitors, such as pirfenidone and nintedanib, suffer from some rather pronounced side effects, and therefore, there is an urgent need to investigate new drugs. In this review, we explore the mechanism of action and signaling pathways of MMP-9 in different tissues and organs, hoping to provide some ideas for developing safer and more effective biologics.

Complex II ambiguities-FADH2 in the electron transfer system

The prevailing notion that reduced cofactors NADH and FADH2 transfer electrons from the tricarboxylic acid cycle to the mitochondrial electron transfer system creates ambiguities regarding respiratory Complex II (CII). CII is the only membrane-bound enzyme in the tricarboxylic acid cycle and is part of the electron transfer system of the mitochondrial inner membrane feeding electrons into the coenzyme Q-junction. The succinate dehydrogenase subunit SDHA of CII oxidizes succinate and reduces the covalently bound prosthetic group FAD to FADH2 in the canonical forward tricarboxylic acid cycle. However, several graphical representations of the electron transfer system depict FADH2 in the mitochondrial matrix as a substrate to be oxidized by CII. This leads to the false conclusion that FADH2 from the β-oxidation cycle in fatty acid oxidation feeds electrons into CII. In reality, dehydrogenases of fatty acid oxidation channel electrons to the Q-junction but not through CII. The ambiguities surrounding Complex II in the literature and educational resources call for quality control, to secure scientific standards in current communications of bioenergetics, and ultimately support adequate clinical applications. This review aims to raise awareness of the inherent ambiguity crisis, complementing efforts to address the well-acknowledged issues of credibility and reproducibility.

Natural Polyphenols in Cancer Management: Promising Role, Mechanisms, and Chemistry

BACKGROUND

Although cancers emerge rapidly and cancer cells divide aggressively, which affects our vital organ systems. Recently, cancer treatments are targeted immune systems mediating intrinsic cellular mechanisms. Natural efficacious polyphenols have been exhibited to help prevent most cancers and reverse the progression of cancers.

METHODS

Many resources have been used to know the promising role of polyphenols in preventing and treating cancers. The electronic databases include Science Direct, Google, Google Scholar, PubMed, and Scopus. The search was limited to the English language only.

RESULTS

Polyphenols have been reported as anti-metastatic agents that explore the promising role of these compounds in cancer prevention. Such agents act through many signaling pathways, including PI3K/Akt and TNF-induced signaling pathways. The chemical modifications of polyphenols and the structure-activity relationships (SARs) between polyphenols and anticancer activities have also been discussed.

CONCLUSION

Many research papers were reported to explain the anti-cancer potential of Polyphenols, The SARs between polyphenols and anti-cancer activities, which correlate structures of polyphenols with significant chemotherapeutic action. The mechanism of anti-cancer potential is to be added for searching for new anti-cancer natural products.

NRF2 Activation by AR-20007 Preserves Renal Tubular Epithelial Cells from Antimycin A-Induced Cell Death via Glutathione Metabolism Regulation

Oxidative stress plays a crucial role in the development and progression of various kidney diseases. Nuclear factor erythroid 2-related factor 2 (NRF2) is the primary transcription factor that protects cells from oxidative stress by regulating cytoprotective genes including those involved in the antioxidant glutathione (GSH) pathway. GSH maintains cellular redox status and affects redox signaling, cell proliferation, and cell death. Antimycin A, an inhibitor of complex III of the electron transport chain, causes oxidative stress and reduces GSH levels. In this study, we induced mitochondrial damage in rat renal proximal tubular cells using antimycin A and investigated cellular viability and levels of NRF2 and GSH. Treatment with antimycin A altered the expression of antioxidant genes, including reduction in the transcription of glutathione-cysteine ligase subunits (Gclc and Gclm) and glutathione reductase (Gsr1), followed by a reduction in total GSH content with a concomitant decrease in NRF2 protein expression. AR-20007, previously described as an NRF2 activator, stabilizes and increases NRF2 protein expression in cells. By stimulating NRF2, AR-20007 increased the expression of antioxidant and detoxifying enzymes, thereby enhancing protection against oxidative stress induced by antimycin A. These data suggest that NRF2 activation effectively inhibits antimycin A-induced oxidative stress and that NRF2 may be a promising therapeutic target for preventing cell death during acute kidney injury.

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.