Chronic Kidney Disease and Gut Microbiota: What Is Their Connection in Early Life?

Assessment of the causal relationship between inflammatory bowel diseases and chronic kidney diseases: A two-sample bidirectional mendelian randomization study among European population

BACKGROUND

Kidney function can be impaired in patients with inflammatory bowel diseases (IBD), including Crohn's diseases (CD) and ulcerative colitis (UC). However, the causal relationship between IBD and chronic kidney diseases (CKD) remains unclear.

METHODS

We determined the causal association between IBD and CKD by performing two-sample bidirectional mendelian randomization (MR) analyses. Independent genetic variants were selected as instrumental variables (IVs) of the exposure from open-access genome-wide association studies (GWAS) among European ancestry. IVs-outcome estimates were extracted from three separate GWAS for IBD and two for CKD, respectively. Inverse-variance-weighted model was used as the primary MR method. The pleiotropic effect and heterogeneity were evaluated. For either direction, analyses were performed per outcome database and were subsequently meta-analysed.

RESULTS

Genetically predicted IBD was associated with higher risk of CKD (OR: 1.045, 95% CI: 1.016-1.073, P = 0.002) by including 42 344 IBD cases and 229 164 controls. Further analyses showed genetic liability to CD increased the risk of CKD (OR: 1.057, 95% CI: 1.027-1.087, p < 0.001) whereas UC did not (OR: 0.999, 95% CI:0.969-1.031, p = 0.970). In contrast, genetically predicted CKD was not associated with IBD (OR: 1.010, 95% CI: 0.965-1.056, p = 0.676), UC (OR: 1.011, 95% CI: 0.948-1.078, p = 0.746) and CD (OR: 1.024; 95% CI: 0.963-1.089, p = 0.447).

CONCLUSIONS

We concluded that CD, but not UC, can increase the risk of CKD causally. CD, but not UC, can increase the risk of chronic kidney disease causally. These findings enhance our understanding of the differential impact of IBD subtypes on CKD. It may be necessary to monitor kidney function regularly in patients with CD.

Drugs with a negative impact on cognitive functions (part 3): antibacterial agents in patients with chronic kidney disease

The relationship between chronic kidney disease (CKD) and cognitive function has received increased attention in recent years. Antibacterial agents (ABs) represent a critical component of therapy regimens in patients with CKD due to increased susceptibility to infections. Following our reviewing work on the neurocognitive impact of long-term medications in patients with CKD, we propose to focus on AB-induced direct and indirect consequences on cognitive function. Patients with CKD are predisposed to adverse drug reactions (ADRs) due to altered drug pharmacokinetics, glomerular filtration decline, and the potential disruption of the blood-brain barrier. ABs have been identified as a major cause of ADRs in vulnerable patient populations. This review examines the direct neurotoxic effects of AB classes (e.g. beta-lactams, fluoroquinolones, aminoglycosides, and metronidazole) on the central nervous system (CNS) in patients with CKD. We will mainly focus on the acute effects on the CNS associated with AB since they are the most extensively studied effects in CKD patients. Moreover, the review describes the modulation of the gut microbiota by ABs, potentially influencing CNS symptoms. The intricate brain-gut-kidney axis emerges as a pivotal focus, revealing the interplay between microbiota alterations induced by ABs and CNS manifestations in patients with CKD. The prevalence of antibiotic-associated encephalopathy in patients with CKD undergoing intravenous AB therapy supports the use of therapeutic drug monitoring for ABs to reduce the number and seriousness of ADRs in this patient population. In conclusion, elucidating AB-induced cognitive effects in patients with CKD demands a comprehensive understanding and tailored therapeutic strategies that account for altered pharmacokinetics and the brain-gut-kidney axis.

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.

Prediction and causal inference of hyperuricemia using gut microbiota

Hyperuricemia (HUA) is a symptom of high blood uric acid (UA) levels, which causes disorders such as gout and renal urinary calculus. Prolonged HUA is often associated with hypertension, atherosclerosis, diabetes mellitus, and chronic kidney disease. Studies have shown that gut microbiota (GM) affect these chronic diseases. This study aimed to determine the relationship between HUA and GM. The microbiome of 224 men and 254 women aged 40 years was analyzed through next-generation sequencing and machine learning. We obtained GM data through 16S rRNA-based sequencing of the fecal samples, finding that alpha-diversity by Shannon index was significantly low in the HUA group. Linear discriminant effect size analysis detected a high abundance of the genera Collinsella and Faecalibacterium in the HUA and non-HUA groups. Based on light gradient boosting machine learning, we propose that HUA can be predicted with high AUC using four clinical characteristics and the relative abundance of nine bacterial genera, including Collinsella and Dorea. In addition, analysis of causal relationships using a direct linear non-Gaussian acyclic model indicated a positive effect of the relative abundance of the genus Collinsella on blood UA levels. Our results suggest abundant Collinsella in the gut can increase blood UA levels.

Hesperidin alleviates zinc-induced nephrotoxicity via the gut-kidney axis in swine

Introduction

Zinc (Zn) is an essential trace element in animals, but excessive intake can lead to renal toxicity damage. Thus, the exploration of effective natural antagonists to reduce the toxicity caused by Zn has become a major scientific problem.

Methods

Here, we found that hesperidin could effectively alleviate the renal toxicity induced by Zn in pigs by using hematoxylin-eosin staining, transmission electron microscope, immunohistochemistry, fluorescence quantitative PCR, and microfloral DNA sequencing.

Results

The results showed that hesperidin could effectively attenuate the pathological injury in kidney, and reduce autophagy and apoptosis induced by Zn, which evidenced by the downregulation of LC3, ATG5, Bak1, Bax, Caspase-3 and upregulation of p62 and Bcl2. Additionally, hesperidin could reverse colon injury and the decrease of ZO-1 protein expression. Interestingly, hesperidin restored the intestinal flora structure disturbed by Zn, and significantly reduced the abundance of Tenericutes (phylum level) and Christensenella (genus level).

Discussion

Thus, altered intestinal flora and intestinal barrier function constitute the gut-kidney axis, which is involved in hesperidin alleviating Zn-induced nephrotoxicity. Our study provides theoretical basis and practical significance of hesperidin for the prevention and treatment of Zn-induced nephrotoxicity through gut-kidney axis.

Preventive effect of Lactobacillus johnsonii YH1136 against uric acid accumulation and renal damages

Background

Hyperuricemia (HUA) is a prevalent metabolic disorder whose development is associated with intestinal microbiota. Therefore, probiotics have emerged as a potential and safe approach for lowering uric acid (UA) levels. However, the underlying mechanisms of many effective probiotic strains remain unknown.

Methods and results

C57BL/6 mice were randomly divided into two groups: control and model groups. The model group received 12 weeks of potassium oxonate. Through 16s sequencing we found that HUA resulted in a significant decrease in the total diversity of all intestinal segments. When each intestinal segment was analyzed individually, the reduction in diversity was only significant in the cecum and colon sections. RDA analysis showed that lactobacilli in the rat colon exhibited a strong correlation with model group, suggesting that Lactobacillus may play an important role in HUA. Consequently, the preventive effects of Lactobacillus johnsonii YH1136 against HUA were investigated. C57BL/6 mice were randomly divided into three groups: control, model and YH1136 groups. The results showed that administering Lactobacillus johnsonii YH1136 effectively reduced serum UA levels in vivo by inhibiting hepatic xanthine oxidase (XOD) activity and promoting renal ABCG2 transporter expression. Moreover, supplementation with Lactobacillus johnsonii YH1136 significantly ameliorated pathological damage in the kidney and liver, thereby reducing UA accumulation.

Conclusion

Hyperuricemia is accompanied by an altered composition of multiple gut bacteria, of which Lactobacillus is a key genus. Lactobacillus johnsonii YH1136 may ameliorate renal involvement in HUA via the gut-kidney axis.

Can the Evidence-Based Use of Probiotics (Notably Saccharomyces boulardii CNCM I-745 and Lactobacillus rhamnosus GG) Mitigate the Clinical Effects of Antibiotic-Associated Dysbiosis?

Dysbiosis corresponds to the disruption of a formerly stable, functionally complete microbiota. In the gut, this imbalance can lead to adverse health outcomes in both the short and long terms, with a potential increase in the lifetime risks of various noncommunicable diseases and disorders such as atopy (like asthma), inflammatory bowel disease, neurological disorders, and even behavioural and psychological disorders. Although antibiotics are highly effective in reducing morbidity and mortality in infectious diseases, antibiotic-associated diarrhoea is a common, non-negligible clinical sign of gut dysbiosis (and the only visible one). Re-establishment of a normal (functional) gut microbiota is promoted by completion of the clinically indicated course of antibiotics, the removal of any other perturbing external factors, the passage of time (i.e. recovery through the microbiota's natural resilience), appropriate nutritional support, and-in selected cases-the addition of probiotics. Systematic reviews and meta-analyses of clinical trials have confirmed the strain-specific efficacy of some probiotics (notably the yeast Saccharomyces boulardii CNCM I-745 and the bacterium Lactobacillus rhamnosus GG) in the treatment and/or prevention of antibiotic-associated diarrhoea in children and in adults. Unusually for a probiotic, S. boulardii is a eukaryote and is not therefore directly affected by antibiotics-making it suitable for administration in cases of antibiotic-associated diarrhoea. A robust body of evidence from clinical trials and meta-analyses shows that the timely administration of an adequately dosed probiotic (upon initiation of antibiotic treatment or within 48 h) can help to prevent or resolve the consequences of antibiotic-associated dysbiosis (such as diarrhoea) and promote the resilience of the gut microbiota and a return to the pre-antibiotic state. A focus on the prescription of evidence-based, adequately dosed probiotics should help to limit unjustified and potentially ineffective self-medication.

The Kidney-Gut Axis as a Novel Target for Nutritional Intervention to Counteract Chronic Kidney Disease Progression

A well-balanced diet is integral for overall health, aiding in managing key risk factors for kidney damage like hypertension while supplying necessary precursors for metabolite production. Dietary choices directly influence the composition and metabolic patterns of the gut microbiota, showing promise as therapeutic tools for addressing various health conditions, including chronic kidney diseases (CKD). CKD pathogenesis involves a decline in the glomerular filtration rate and the retention of nitrogen waste, fostering gut dysbiosis and the excessive production of bacterial metabolites. These metabolites act as uremic toxins, contributing to inflammation, oxidative stress, and tissue remodeling in the kidneys. Dietary interventions hold significance in reducing oxidative stress and inflammation, potentially slowing CKD progression. Functional ingredients, nutrients, and nephroprotective phytoconstituents could modulate inflammatory pathways or impact the gut mucosa. The "gut-kidney axis" underscores the impact of gut microbes and their metabolites on health and disease, with dysbiosis serving as a triggering event in several diseases, including CKD. This review provides a comprehensive overview, focusing on the gut-liver axis, and explores well-established bioactive substances as well as specific, less-known nutraceuticals showing promise in supporting kidney health and positively influencing CKD progression.

A Network Pharmacology and Molecular-Docking-Based Approach to Identify the Probable Targets of Short-Chain Fatty-Acid-Producing Microbial Metabolites against Kidney Cancer and Inflammation

(1) Background: A large and diverse microbial population exists in the human intestinal tract, which supports gut homeostasis and the health of the host. Short-chain fatty acid (SCFA)-secreting microbes also generate several metabolites with favorable regulatory effects on various malignancies and immunological inflammations. The involvement of intestinal SCFAs in kidney diseases, such as various kidney malignancies and inflammations, has emerged as a fascinating area of study in recent years. However, the mechanisms of SCFAs and other metabolites produced by SCFA-producing bacteria against kidney cancer and inflammation have not yet been investigated. (2) Methods: We considered 177 different SCFA-producing microbial species and 114 metabolites from the gutMgene database. Further, we used different online-based database platforms to predict 1890 gene targets associated with metabolites. Moreover, DisGeNET, OMIM, and Genecard databases were used to consider 13,104 disease-related gene targets. We used a Venn diagram and various protein-protein interactions (PPIs), KEGG pathways, and GO analyses for the functional analysis of gene targets. Moreover, the subnetwork of protein-protein interactions (through string and cytoscape platforms) was used to select the top 20% of gene targets through degree centrality, betweenness centrality, and closeness centrality. To screen the possible candidate compounds, we performed an analysis of the ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties of metabolites and then found the best binding affinity using molecular docking simulation. (3) Results: Finally, we found the key gene targets that interact with suitable compounds and function against kidney cancer and inflammation, such as MTOR (with glycocholic acid), PIK3CA (with 11-methoxycurvularin, glycocholic acid, and isoquercitrin), IL6 (with isoquercitrin), PTGS2 (with isoquercitrin), and IGF1R (with 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine, isoquercitrin), showed a lower binding affinity. (4) Conclusions: This study provides evidence to support the positive effects of SCFA-producing microbial metabolites that function against kidney cancer and inflammation and makes integrative research proposals that may be used to guide future studies.

An Overview of Chronic Kidney Disease Pathophysiology: The Impact of Gut Dysbiosis and Oral Disease

Chronic kidney disease (CKD) is a severe condition and a significant public health issue worldwide, carrying the burden of an increased risk of cardiovascular events and mortality. The traditional factors that promote the onset and progression of CKD are cardiometabolic risk factors like hypertension and diabetes, but non-traditional contributors are escalating. Moreover, gut dysbiosis, inflammation, and an impaired immune response are emerging as crucial mechanisms in the disease pathology. The gut microbiome and kidney disease exert a reciprocal influence commonly referred to as "the gut-kidney axis" through the induction of metabolic, immunological, and endocrine alterations. Periodontal diseases are strictly involved in the gut-kidney axis for their impact on the gut microbiota composition and for the metabolic and immunological alterations occurring in and reciprocally affecting both conditions. This review aims to provide an overview of the dynamic biological interconnections between oral health status, gut, and renal pathophysiology, spotlighting the dynamic oral-gut-kidney axis and raising whether periodontal diseases and gut microbiota can be disease modifiers in CKD. By doing so, we try to offer new insights into therapeutic strategies that may enhance the clinical trajectory of CKD patients, ultimately advancing our quest for improved patient outcomes and well-being.

Gutted: constipation in children with chronic kidney disease and on dialysis

Functional constipation is a common problem in otherwise healthy children. Children with chronic kidney disease (CKD) and on dialysis have additional disease-related risk factors including the uremic milieu, fluid and dietary restrictions, and decreased physical activity, as well as treatment-related risk factors such as dialysis therapy and polypharmacy that contribute to and compound the problem. Constipation causes significant distress for children and their caregivers. In children on peritoneal dialysis, severe constipation can impede catheter function and ultrafiltration. Accumulating evidence points to a possible bidirectional relationship between constipation and CKD, potentially mediated by gut dysbiosis with consequent increased generation of gut-derived uremic toxins and disruption of intestinal epithelium integrity leading to translocation of noxious luminal contents into the circulation inducing systemic inflammation. Effective management of constipation is required but there is little published data on the safety and effectiveness of treatments in adults or children with CKD. In this review, we discuss the diagnosis and epidemiology of functional constipation, provide an overview of its pathophysiology, summarize the therapeutic management, and reflect on the challenges in children with CKD.

Probiotics mitigate kidney damage after exposure to Sri Lanka's local groundwater from chronic kidney disease with uncertain etiology (CKDu) prevalent area in zebrafish

Groundwater in Sri Lanka, contaminated with environmental toxins, is suspected to potentially induce chronic kidney disease of uncertain etiology (CKDu) in humans. This study aims to elucidate the potential mitigating effects of probiotics on kidney damage induced by exposure to this local groundwater (LW) in zebrafish. We used zebrafish as a model organism and exposed them to local groundwater to evaluate the risk of CKDu. Probiotics were then added at a concentration of 108 colony-forming units per milliliter (CFU/mL). Our findings revealed that exposure to local groundwater resulted in abnormalities, such as tail deletion and spinal curvature in zebrafish larvae. However, the addition of probiotics mitigated these effects, improving the hatching rate, heart rate, length, weight, deformity rate, survival rate, and abnormal behavior of zebrafish. It also positively influenced the differential expression levels of kidney development and immunity-related genes (dync2h1, foxj1, pkd2, gata3, slc20a1, il1β, and lyso). Furthermore, exposure to LW decreased both the diversity and abundance of microbiota in zebrafish larvae. However, treatment with probiotics, such as L. plantarum and L. rhamnosus partially restored the disrupted gut microbiota and significantly impacted the cellular process pathways of the microbial community, as determined by KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis. In conclusion, this study highlights the risks associated with Sri Lanka's local groundwater from a CKDu prevalent area and confirms the beneficial effects of different probiotics. These findings may provide new insights into bacterial function in host kidney health.

Oxalate (dys)Metabolism: Person-to-Person Variability, Kidney and Cardiometabolic Toxicity

Oxalate is a metabolic end-product whose systemic concentrations are highly variable among individuals. Genetic (primary hyperoxaluria) and non-genetic (e.g., diet, microbiota, renal and metabolic disease) reasons underlie elevated plasma concentrations and tissue accumulation of oxalate, which is toxic to the body. A classic example is the triad of primary hyperoxaluria, nephrolithiasis, and kidney injury. Lessons learned from this example suggest further investigation of other putative factors associated with oxalate dysmetabolism, namely the identification of precursors (glyoxylate, aromatic amino acids, glyoxal and vitamin C), the regulation of the endogenous pathways that produce oxalate, or the microbiota's contribution to oxalate systemic availability. The association between secondary nephrolithiasis and cardiovascular and metabolic diseases (hypertension, type 2 diabetes, and obesity) inspired the authors to perform this comprehensive review about oxalate dysmetabolism and its relation to cardiometabolic toxicity. This perspective may offer something substantial that helps advance understanding of effective management and draws attention to the novel class of treatments available in clinical practice.

The NOS/NO System in Renal Programming and Reprogramming

Nitric oxide (NO) is a gaseous signaling molecule with renoprotective properties. NO can be produced in NO synthase (NOS)-dependent or -independent manners. NO deficiency plays a decisive role in chronic kidney disease (CKD). Kidney development can be affected in response to adverse intrauterine conditions that induce renal programming, thereby raising the risk of developing CKD in adulthood. Conversely, detrimental programming processes could be postponed or halted prior to the onset of CKD by early treatments, namely reprogramming. The current review provides an overview of the NOS/NO research performed in the context of renal programming and reprogramming. NO deficiency has been increasingly found to interact with the different mechanisms behind renal programming, such as oxidative stress, aberrant function of the renin-angiotensin system, disturbed nutrient-sensing mechanisms, dysregulated hydrogen sulfide signaling, and gut microbiota dysbiosis. The supplementation of NOS substrates, the inhibition of asymmetric dimethylarginine (ADMA), the administration of NO donors, and the enhancement of NOS during gestation and lactation have shown beneficial effects against renal programming in preclinical studies. Although human data on maternal NO deficiency and offspring kidney disease are scarce, experimental data indicate that targeting NO could be a promising reprogramming strategy in the setting of renal programming.

Exploring a Complex Interplay: Kidney-Gut Axis in Pediatric Chronic Kidney Disease

The human intestinal microbiota is a highly intricate structure with a crucial role in promoting health and preventing disease. It consists of diverse microbial communities that inhabit the gut and contribute to essential functions such as food digestion, nutrient synthesis, and immune system development. The composition and function of the gut microbiota are influenced by a variety of factors, including diet, host genetics, and environmental features. In pediatric patients, the gut microbiota is particularly dynamic and vulnerable to disruption from endogenous and exogenous factors. Recent research has focused on understanding the interaction between the gut and kidneys. In individuals with chronic kidney disease, there is often a significant disturbance in the gut microbiota. This imbalance can be attributed to factors like increased levels of harmful toxins from the gut entering the bloodstream, inflammation, and oxidative stress. This review looks at what is known about the link between a child's gut-kidney axis, how dysbiosis, or an imbalance in the microbiome, affects chronic kidney disease, and what treatments, both pharmaceutical and non-pharmaceutical, are available for this condition.

Chronic Kidney Disease: Underlying Molecular Mechanisms-A Special Issue Overview

Chronic kidney disease (CKD) is an epidemic health issue that requires global attention [...].

Sulfur-Containing Amino Acids, Hydrogen Sulfide, and Sulfur Compounds on Kidney Health and Disease

Hydrogen sulfide (H₂S) plays a decisive role in kidney health and disease. H₂S can ben synthesized via enzymatic and non-enzymatic pathways, as well as gut microbial origins. Kidney disease can originate in early life induced by various maternal insults throughout the process, namely renal programming. Sulfur-containing amino acids and sulfate are essential in normal pregnancy and fetal development. Dysregulated H₂S signaling behind renal programming is linked to deficient nitric oxide, oxidative stress, the aberrant renin-angiotensin-aldosterone system, and gut microbiota dysbiosis. In animal models of renal programming, treatment with sulfur-containing amino acids, N-acetylcysteine, H₂S donors, and organosulfur compounds during gestation and lactation could improve offspring's renal outcomes. In this review, we summarize current knowledge regarding sulfide/sulfate implicated in pregnancy and kidney development, current evidence supporting the interactions between H₂S signaling and underlying mechanisms of renal programming, and recent advances in the beneficial actions of sulfide-related interventions on the prevention of kidney disease. Modifying H₂S signaling is the novel therapeutic and preventive approach to reduce the global burden of kidney disease; however, more work is required to translate this into clinical practice.

The Impact of Nutrient Intake and Metabolic Wastes during Pregnancy on Offspring Hypertension: Challenges and Future Opportunities

Hypertension can have its origin in early life. During pregnancy, many metabolic alterations occur in the mother that have a crucial role in fetal development. In response to maternal insults, fetal programming may occur after metabolic disturbance, resulting in programmed hypertension later in life. Maternal dietary nutrients act as metabolic substrates for various metabolic processes via nutrient-sensing signals. Different nutrient-sensing pathways that detect levels of sugars, amino acids, lipids and energy are integrated during pregnancy, while disturbed nutrient-sensing signals have a role in the developmental programming of hypertension. Metabolism-modulated metabolites and nutrient-sensing signals are promising targets for new drug discovery due to their pathogenic link to hypertension programming. Hence, in this review, we pay particular attention to the maternal nutritional insults and metabolic wastes affecting fetal programming. We then discuss the role of nutrient-sensing signals linking the disturbed metabolism to hypertension programming. This review also summarizes current evidence to give directions for future studies regarding how to prevent hypertension via reprogramming strategies, such as nutritional intervention, targeting nutrient-sensing signals, and reduction of metabolic wastes. Better prevention for hypertension may be possible with the help of novel early-life interventions that target altered metabolism.

Chronic kidney disease-induced muscle atrophy: Molecular mechanisms and promising therapies

Chronic kidney disease (CKD) is a high-risk chronic catabolic disease due to its high morbidity and mortality. CKD is accompanied by many complications, leading to a poor quality of life, and serious complications may even threaten the life of CKD patients. Muscle atrophy is a common complication of CKD. Muscle atrophy and sarcopenia in CKD patients have complex pathways that are related to multiple mechanisms and related factors. This review not only discusses the mechanisms by which inflammation, oxidative stress, mitochondrial dysfunction promote CKD-induced muscle atrophy but also explores other CKD-related complications, such as metabolic acidosis, vitamin D deficiency, anorexia, and excess angiotensin II, as well as other related factors that play a role in CKD muscle atrophy, such as insulin resistance, hormones, hemodialysis, uremic toxins, intestinal flora imbalance, and miRNA. We highlight potential treatments and drugs that can effectively treat CKD-induced muscle atrophy in terms of complication treatment, nutritional supplementation, physical exercise, and drug intervention, thereby helping to improve the prognosis and quality of life of CKD patients.

Role of the Gut Microbiota in Children with Kidney Disease

Disruption of the composition and structure of the gut microbiota, namely dysbiosis, dictates the pathophysiology of kidney diseases. The bidirectional kidney-gut axis is of interest in chronic kidney disease (CKD); the uremic milieu leads to intestinal dysbiosis and gut microbial metabolites and toxins implicated in the loss of kidney function and increased comorbidity burden. Considering that kidney diseases can originate in childhood or even earlier in fetal life, identification of the pathogenetic connection between gut microbiota dysbiosis and the development of pediatric renal diseases deserves more attention. This review concentrates on the pathogenic link between dysbiotic gut microbiota and pediatric renal diseases, covering CKD, kidney transplantation, hemodialysis and peritoneal dialysis, and idiopathic nephrotic syndrome. Gut microbiota-targeted therapies including dietary intervention, probiotics, prebiotics, postbiotics and fecal microbial transplantation are discussed for their potential for the treatment of pediatric renal diseases. A deeper understanding of gut microbiota in pediatric renal diseases will aid in developing innovative gut microbiota-targeted interventions for preventing or attenuating the global burden of kidney diseases.

Dietary Resveratrol Butyrate Monoester Supplement Improves Hypertension and Kidney Dysfunction in a Young Rat Chronic Kidney Disease Model

Chronic kidney disease (CKD) remains a public health problem. Certain dietary supplements can assist in the prevention of CKD progression. In this regard, resveratrol is a polyphenol and has a potential therapeutic role in alleviating CKD. We previously utilized butyrate in order to improve the bioavailability of resveratrol via esterification and generated a resveratrol butyrate monoester (RBM). In this study, the hypothesis that RBM supplementation is able to protect against kidney dysfunction and hypertension was tested by using an adenine-induced CKD model. For this purpose, three-week-old male Sprague Dawley rats (n = 40) were equally categorized into: group 1-CN (sham control); group 2-CKD (adenine-fed rats); group 3-REV (CKD rats treated with 50 mg/L resveratrol); group 4-MEL (CKD rats treated with 25 mg/L RBM); and group 5-MEH (CKD rats treated with 50 mg/L RBM). At the end of a 12-week period, the rats were then euthanized. The adenine-fed rats displayed hypertension and kidney dysfunction, which were attenuated by dietary supplementation with RBM. The CKD-induced hypertension coincided with: decreased nitric oxide (NO) bioavailability; augmented renal protein expression of a (pro)renin receptor and angiotensin II type 1 receptor; and increased oxidative stress damage. Additionally, RBM and resveratrol supplementation shaped distinct gut microbiota profiles in the adenine-treated CKD rats. The positive effect of high-dose RBM was shown together with an increased abundance of the genera Duncaniella, Ligilactobacillus, and Monoglobus, as well as a decrease in Eubacterium and Schaedierella. Importantly, the mechanism of action of the RBM supplementation may be related to the restoration of NO, rebalancing of the RAS, a reduction in oxidative stress, and alterations to the gut microbiota. Moreover, RBM supplementation shows promise for the purposes of improving CKD outcomes and hypertension. As such, further translation to human studies is warranted.

Perinatal Oxidative Stress and Kidney Health: Bridging the Gap between Animal Models and Clinical Reality

Oxidative stress arises when the generation of reactive oxygen species or reactive nitrogen species overwhelms antioxidant systems. Developing kidneys are vulnerable to oxidative stress, resulting in adult kidney disease. Oxidative stress in fetuses and neonates can be evaluated by assessing various biomarkers. Using animal models, our knowledge of oxidative-stress-related renal programming, the molecular mechanisms underlying renal programming, and preventive interventions to avert kidney disease has grown enormously. This comprehensive review provides an overview of the impact of perinatal oxidative stress on renal programming, the implications of antioxidant strategies on the prevention of kidney disease, and the gap between animal models and clinical reality.

Perinatal Propionate Supplementation Protects Adult Male Offspring from Maternal Chronic Kidney Disease-Induced Hypertension

Emerging evidence supports that early-life disturbance of gut microbiota has an impact on adult disease in later life. Offspring hypertension can be programmed by maternal chronic kidney disease (CKD). Conversely, perinatal use of gut microbiota-targeted therapy has been implemented to reverse programming processes and prevent hypertension. Short-chain fatty acids (SCFAs), the major gut microbiota-derived metabolites, can be applied as postbiotics. Propionate, one of predominant SCFAs, has been shown to have antihypertensive property. We examined whether perinatal propionate supplementation can prevent offspring hypertension induced by maternal CKD. CKD was induced by chow supplemented with 0.5% adenine for 3 weeks before pregnancy. Propionate (P) was supplemented at 200 mmol/L in drinking water during pregnancy and lactation. Male offspring were divided into four groups (n = 7–8/group): control, CKD, control+propionate (CP), and CKD+propionate (CKDP). Maternal CKD-induced offspring hypertension was reversed by perinatal propionate supplementation. The protective effects of perinatal propionate treatment were related to increased propionate-generating bacteria Clostridium spp. and plasma propionate level, increased expression of renal G protein-coupled receptor 41 (GPR41, a SCFA receptor), augmentation of α-diversity, and shifts in gut microbiota composition. In summary, our results highlight that maternal CKD-induced offspring hypertension can be prevented by the use of gut microbial metabolite SCFAs in early life, which could shed light on the prevention of the current hypertension pandemic.