Gut-kidney Axis Research Articles

Polysaccharide isolated from Dioscorea septemloba improves hyperuricemia and alleviates renal fibrosis through gut-kidney axis in mice

Hyperuricemia (HUA) is a common metabolic disorder that often accompanies kidney diseases such as tubule damage and renal interstitial fibrosis. The preventive and therapeutic effects of Dioscorea septemloba, an anti-HUA herb, polysaccharide of which was considered as the main active ingredient on HUA, need to be explored. The major polysaccharide component, BXP, was purified from Dioscorea septemloba, with an average molecular weight of 10.432 kDa. Structural analysis inferred that BXP backbone was composed of t-β-D-Glcp-(1 → 4)-α-D-Glcp-(1 → 4)-α-D-Glcp-(1 → 4, 3)-β-D-Glcp-(1→, along with the side chain of →1)-α-D-Glcp-(6, 4 → 3, 4)-β-D-Glcp-(1→. The HUA mouse model was further established to clarify the underlying effect of BXP on HUA alleviation. As results shown, BXP decreased serum uric acid by inhibiting XOD and regulating urate transporter expression (GLUT9, OAT3, OAT1, URAT1 and ABCG2) in HUA mice, as well as relieving kidney and liver damage. Moreover, results of microbiome and metabolomics indicated that BXP improved the abundance of gut bacteria and reversed the Lipids-related metabolism disorder caused by HUA. This study indicated that BXP had potential to alleviate HUA and kidney disease through the gut-kidney axis in mice.

Effects of Abelmoschus manihot (L.) and its combination with irbesartan in the treatment of diabetic nephropathy via the gut–kidney axis

BackgroundClinical observations have recently shown that Abelmoschus manihot (L.) in the form of Huangkui capsule (HKC) and in combination with irbesartan (EB) is an effective therapy for diabetic nephropathy (DN) in patients with type 2 diabetes (T2D). The present study aims to explore the mechanisms underlying the therapeutic efficacies of HKC and its combination with EB in DN via the gut-kidney axis.MethodsHKC, EB, and their combination or vehicle were administered in db/db mice, which is an animal model for the study of T2D and DN. Comparative analyses of the gut microbiota, serum metabolites, and kidney transcriptomics before and after drug administration were performed.ResultsAfter treatment with HKC, EB, and their combination for 4 weeks, the urinary albumin-to-creatinine ratios decreased significantly in the db/db mice with DN. In terms of the gut microbiota, the abundances of Faecalitalea, Blautia, and Streptococcus increased but those of Bacteroidetes, Firmicutes, Enterobacteriaceae, and Desulfovibrio decreased. Parallelly, serum metabolites, mainly including quercetin 3′-glucuronide and L-dopa, were elevated while cortisol and cytochalasin B were reduced. Furthermore, the S100a8, S100a9, Trem1, and Mmp7 genes in the kidneys were downregulated. These altered elements were associated with proteinuria/albuminuria reduction. However, EB had no effects on the changes in blood pressure and specific differentially expressed genes in the kidneys.ConclusionThe present study provides experimental evidence that HKC regulates the gut microbiota, circulating metabolites, and renal gene activities, which are useful for better understanding of the action mechanisms of A. manihot in the treatment of DN through the gut-kidney axis.

Mizhuo Guanchangye enema delays the decline of renal function in rats with chronic kidney disease by intervening in the TLR4/MyD88/NF-κB pathway

BackgroundChronic kidney disease (CKD) is a prevalent chronic condition that poses a significant threat to human health. There is a close connection between the gut and kidneys, jointly influencing the onset and progression of CKD through the “gut-kidney axis.” Traditional Chinese medicine has shown potential in CKD treatment, but the specific mechanisms require further investigation.ObjectivesThis study aims to explore the protective effects of Mizhuo Enema (MZGCY) on kidney function in CKD rats by regulating the TLR4/MyD88/NF-κB signaling pathway.MethodsThe researcher employed a CKD rat model, which was divided into four groups: Control, Model, half-dose Mizhuo Guanchangye (1/2 MZGCY), and full-dose Mizhuo Guanchangye (MZGCY). Post enema administration, assessments were conducted on kidney function indicators, which included blood urea nitrogen (BUN), serum creatinine (SCR), and 24-h urinary protein. Additionally, measurements were taken for intestinal toxic substances such as indoxyl sulfate (IS) and lipopolysaccharide (LPS), as well as inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Examinations of pathological changes in both the intestines and kidneys were also performed. During this process, immunofluorescence was utilized to detect the expression levels of proteins toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), and nuclear factor kappa B (NF-κB) in the intestinal tissues.ResultsIt was found that after enema treatment, the BUN, SCR, and 24-h urinary protein levels in the MZGCY and 1/2 MZGCY groups significantly decreased, indicating notable improvement in kidney function. Compared to the model group, the IS, LPS, IL-6, and TNF-α levels in the MZGCY and 1/2 MZGCY groups were significantly reduced. Immunofluorescence showed a marked decrease in the expression of TLR4, MyD88, and NF-κB proteins in the intestines of the MZGCY group.ConclusionMZGCY significantly reduces the levels of intestinal toxins and inflammatory factors in the serum of CKD rats by interfering with the TLR4/MyD88/NF-κB signaling pathway, thereby improving intestinal and renal pathological changes and delaying CKD progression. This study demonstrates that MZGCY has significant renal protective effects, providing a new potential approach for CKD treatment.

Fecal bile acid dysmetabolism and reduced ursodeoxycholic acid correlate with novel microbial signatures in feline chronic kidney disease.

Microbial-derived secondary bile acids (SBAs) are reabsorbed and sensed via host receptors modulating cellular inflammation and fibrosis. Feline chronic kidney disease (CKD) occurs with progressive renal inflammation and fibrosis, mirroring the disease pathophysiology of human CKD patients. Prospective cross-sectional study compared healthy cats (n = 6) with CKD (IRIS Stage 2 n = 17, Stage 3 or 4 n = 11). Single timepoint fecal samples from all cats underwent targeted bile acid metabolomics. 16S rRNA gene amplicon sequencing using DADA2 with SILVA taxonomy characterized the fecal microbiota. CKD cats had significantly reduced fecal concentrations (median 12.8 ng/mg, Mann-Whitney p = 0.0127) of the SBA ursodeoxycholic acid (UDCA) compared to healthy cats (median 39.4 ng/mg). Bile acid dysmetabolism characterized by <50% SBAs was present in 8/28 CKD and 0/6 healthy cats. Beta diversity significantly differed between cats with <50% SBAs and > 50% SBAs (PERMANOVA p < 0.0001). Twenty-six amplicon sequence variants (ASVs) with >97% nucleotide identity to Peptacetobacter hiranonis were identified. P. hiranonis combined relative abundance was significantly reduced (median 2.1%) in CKD cats with <50% SBAs compared to CKD cats with >50% SBAs (median 13.9%, adjusted p = 0.0002) and healthy cats with >50% SBAs (median 15.5%, adjusted p = 0.0112). P. hiranonis combined relative abundance was significantly positively correlated with the SBAs deoxycholic acid (Spearman r = 0.5218, adjusted p = 0.0407) and lithocholic acid (Spearman r = 0.5615, adjusted p = 0.0156). Three Oscillospirales ASVs and a Roseburia ASV were also identified as significantly correlated with fecal SBAs. The gut-kidney axis mediated through microbial-derived SBAs appears relevant to the spontaneous animal CKD model of domestic cats. This includes reduced fecal concentrations of the microbial-derived SBA UDCA, known to regulate inflammation and fibrosis and be reno-protective. Microbes correlated with fecal SBAs include bai operon containing P. hiranonis, as well as members of Oscillospirales, which also harbor a functional bai operon. Ultimately, CKD cats represent a translational opportunity to study the role of SBAs in the gut-kidney axis, including the potential to identify novel microbial-directed therapeutics to mitigate CKD pathogenesis in veterinary patients and humans alike.

Peritoneal dialysis promotes microbial-driven biosynthesis pathways of sesquiterpenes and triterpenes compounds in end-stage renal disease patients

The concept of the gut-kidney axis is gaining significant attention due to the close relationship between gut microbiota and kidney disease. Peritoneal dialysis is recognized as a crucial renal replacement therapy for end-stage renal disease (ESRD). The alterations in gut microbiota and related mechanisms after receiving this dialysis method are not fully understood. This study conducted shotgun metagenomic sequencing on fecal samples from 11 end-stage renal disease patients who did not receive dialysis (ESRD_N) and 7 patients who received peritoneal dialysis (ESRD_P). After quality control and correlation analysis of the data, our study is aimed at exploring the impact of peritoneal dialysis on the gut microbiota and health of ESRD patients. Our research findings indicate that the complexity and aggregation characteristics of gut microbiota interactions increase in ESRD_P. In addition, the gut microbiota drives the biosynthesis pathways of sesquiterpenes and triterpenes in ESRD_P patients, which may contribute to blood purification and improve circulation. Therefore, our research will lay the foundation for the prevention and treatment of ESRD.

Oxaluria in inflammatory bowel diseases (review)

AIM: to analyse and synthesize Russian and foreign literature, to get acquainted with the concept of oxaluria, its types, transport mechanisms of oxalate transport in the intestine and the relationship between hyperoxaluria and inflammatory bowel diseases in order to identify possible options for therapeutic action on the mechanisms of development of these pathologies. MATERIALS AND METHODS: the literature review was based on the Internet data, including bibliographic directories, books, journals, and original articles. The literature sources used for the article reflect the essence of the described problem to the fullest extent possible and can be useful for both practicing physicians and students of medical universities. RESULTS: the gastrointestinal tract through epithelial transport of oxalate plays an exclusive role in oxalate homeostasis and hyperoxaluria. Metabolism of dietary oxalate and the formation of endogenous oxalate, its secretion, absorption, transport and biodegradation by intestinal microflora may influence the excretion of this compound by the kidneys. Knowledge of the interrelated relationships of the gut-kidney axis, mechanisms of transport, transport and biodegradation of oxalate, especially in inflammatory bowel disease, is of great importance for understanding the pathophysiology of hyperoxaluria as a risk factor for urinary stone formation with a point of pharmacological action in the gut. This literature review introduces the concept and forms of oxaluria, shows the classification of oxaluria, describes each form, and broadly explains the metabolism and mechanisms of oxalate transport in the human body. Special attention is given to intestinal hyperoxaluria and anion exchangers belonging to the large multifunctional SLC26 gene family, most of which are expressed throughout the gastrointestinal tract. The authors emphasise their current role in intestinal oxalate transport, as well as methods of possible drug action on the mechanisms of hyperoxaluria. CONCLUSION: a multidisciplinary approach is needed to address the problems of intestinal hyperoxaluria and, consequently, the treatment of urolithiasis. The role of newly identified intestinal and renal anion exchangers is not fully understood, hence the targets and mechanisms of action on these types of exchangers with the possibility of preventing the development of urolithiasis are not fully understood. Further randomised studies on the problem under investigation are needed.

Mendelian insights: Irritable bowel syndrome as a predictor of upper urinary tract calculi.

Patients with irritable bowel syndrome (IBS) have a notably higher rate of consultations in urology clinics compared to other clinics. They often present with symptoms such as lumbar pain, dysuria, and urinary difficulty that are also associated with upper urinary tract calculi (UUTC). UUTC are the leading cause of nephrectomy in non-oncological cases, early screening for high-risk populations is deemed necessary. We investigated the relationship between IBS and UUTC using a two-sample Mendelian randomization (MR) approach, with the primary analysis conducted using the inverse variance weighting method. To enhance the robustness of our findings, we conducted sensitivity analyses employing Cochran Q test, MR-Egger intercept, and MR-PRESSO. Additionally, we included type 2 diabetes in a multivariate Mendelian randomization analysis for further exploration. Our two-sample MR analysis, employing the inverse variance weighting method, suggested a positive association between IBS and UUTC, with an odds ratio of 1.47, a 95% confidence interval from 1.01 to 2.15, and a P-value of .442. Both weighted median and MR Egger analyses also indicated that IBS may be a risk factor for UUTC, although the results were not statistically significant. The Cochran Q test revealed no evidence of heterogeneity (P > .05). The MR-Egger intercept and MR-PRESSO analyses did not support the presence of pleiotropy (P > .05), and no outliers were detected by MR-PRESSO. Sensitivity analyses reinforce the reliability of our findings. Multivariate MR analysis further confirmed that IBS is a risk confirmed factor for UUTC, with significant results (P < .05). IBS is identified as one of the etiological factors for UUTC, enhancing our understanding of the gut-kidney axis. The specific mechanisms underlying this association warrant further investigation. Clinicians should consider the importance of monitoring for UUTC in patients with IBS.

Gut microbiota alterations in renal transplant recipients and the risk of urinary tract infection and delayed graft function: A preliminary prospective study.

The implication of gut microbiota in the gut-kidney axis affects the pathophysiology of chronic kidney disease (CKD). Gut microbiota composition changes during CKD. We aimed to determine the relative frequency of important gut microbiota members in end-stage renal disease (ERSD) patients before and after renal transplantation compared to healthy subjects. Fifteen kidney transplant patients and 10 healthy subjects were recruited in this case-control prospective study. Fecal samples were taken sequentially from all patients before kidney transplantation, 1 week, and 1 month after it. The relative frequency of Lactobacillus spp., Bifidobacterium spp., Akkermansia muciniphila, Bacteroides fragilis, Escherichia coli, and Faecalibacterium pruasnitzii were determined through quantitative PCR. The obtained data was statistically analyzed by Stata software (Stata Corporation, USA). The mean log number of all bacteria was significantly higher in healthy individuals than kidney transplant recipients (p < 0.001) except for Lactobacillus where the mean levels were almost identical in the two groups (p = 0.67). Moreover, 20% (3) of patients developed a urinary tract infection. Besides, 2 (13.33%) patients were diagnosed with delayed graft function. There were no statistically significant differences regarding changing trends in bacteria log number of Akkermansia muciniphila (p = 0.12), Bacteroid fragilis (p = 0.75), Bifidobacterium (p = 0.99), Escherichia coli (p = 0.5), Faecalibacterium (p = 0.98), and Lactobacilli (p = 0.93) between patients with and without delayed graft function (DGF). Gut microbiota composition in patients with ESRD was significantly different from those without it. However, the microbiota profile did not significantly differ in patients with and without DGF.

The Efficacy and Safety of Probiotic Combinations Lobun Forte® Versus Renadyl® in Patients With Chronic Kidney Disease: A Comparative, Phase IV, Randomized, Open-Label, Active-Controlled, Parallel Study.

Chronic kidney disease (CKD) often leads to gut microbiota imbalance, accelerating disease progression and increasing uremic toxins and inflammation. We conducted a randomized clinical trial comparing outcomes between two multi-strain probiotic supplements Lobun Forte® (Sanzyme P Ltd, Hyderabad, India) containing Streptococcus thermophilus, Lactobacillus acidophilus, Bifidobacterium longum, and Bacillus coagulans and Renadyl® (Kibow Biotech, LLC., Pennsylvania, United States) containing S. thermophilus, L. acidophilus, and B. longum. Sixty patients with stage 3-4 CKD were randomized to receive either Lobun Forte (n=30) or Renadyl (n=30) for six months, with each supplement providing 45 billion CFU/capsule, twice daily. Primary outcomes included quality of life (QoL) (Short-Form 8 (SF-8) score), reductions in uremic toxins (p-cresyl sulfate (PCS), 3-indoxyl sulfate (IS), indole-3-acetic acid (IAA)), blood urea nitrogen (BUN), serum creatinine, and serum uric acid. Secondary outcomes assessed oxidative stress, inflammatory biomarkers, and estimated glomerular filtration rate (eGFR). Results: Both Lobun Forte and Renadyl groups showed significant improvements in QoL, with Lobun Forte achieving a 53.5% improvement (16.43 point increase) and Renadyl a 51.1% improvement (15.27 point increase) in SF-8 scores (p < 0.0001). Thelevels of IS decreased significantly in both groups (p < 0.0001), with Lobun Forte reducing IS by 29.72% and Renadyl by 24.20%. In terms of other uremic toxins, Lobun Forte showed non-significant (p > 0.05) reductions in mean PCS (7.63%) and IAA (15.57%), whereas Renadyl demonstrated a significant (p = 0.0314) decrease in PCS (20.75%) and a non-significant (p > 0.05) reduction in IAA (12.35%). Both groups showed significant (p < 0.0001) reductions in BUN and serum creatinine levels. Serum uric acid levels showed a significant (p = 0.0448) reduction with Lobun Forte while Renadyl exhibited a non-significant reduction (p = 0.1034). Lobun Forte significantly (p = 0.0359) reduced mean high-sensitivity C-reactive protein (hsCRP) levels, while Renadyl showed a non-significant reduction (p = 0.0876). Both groups had non-significant reductions in interleukin-6 and tumor necrosis factor-alpha levels (p > 0.05). Further, both groups experienced significant (p < 0.0001) increases in mean glutathione levels and nitric oxide levels. Additionally, Renadyl resulted in a significant reduction in mean malondialdehyde, whereas Lobun Forte showed a non-significant reduction. Both probiotics significantly (p < 0.0001) improved eGFR, with Lobun Forte increasing it by 40.4% and Renadyl by 36.9%. Both probiotics were well tolerated, with a favorable safety profile throughout the study. Conclusion: Both Lobun Forte and Renadyl effectively improve the quality of life in patients with stage 3-4 CKD by modulation of uremic toxins, renal parameters, inflammatory biomarkers, oxidative biomarkers, and eGFR. These findings suggest that both probiotics may help delay CKD progression by modulating the gut-kidney axis.

Renoprotective effects of empagliflozin in high-fat diet-induced obesity-related glomerulopathy by regulation of gut-kidney axis.

The increasing prevalence of obesity-related glomerulopathy (ORG) poses a significant threat to public health. Sodium-glucose cotransporter-2 (SGLT2) inhibitors effectively reduce body weight and total fat mass in individuals with obesity and halt the progression of ORG. However, the underlying mechanisms of their reno-protective effects in ORG remain unclear. We established a high-fat diet-induced ORG model using C57BL/6J mice, which were divided into three groups: normal chow diet (NCD group), high-fat diet (HFD) mice treated with placebo (ORG group), and HFD mice treated with empagliflozin (EMPA group). We conducted 16S ribosomal RNA gene sequencing of feces and analyzed metabolites from kidney, feces, liver, and serum samples. ORG mice showed increased urinary albumin creatinine ratio, cholesterol, triglyceride levels, and glomerular diameter compared with NCD mice (all P < 0.05). EMPA treatment significantly alleviated these parameters (all P < 0.05). Multitissue metabolomics analysis revealed lipid metabolic reprogramming in ORG mice, which was significantly altered by EMPA treatment. MetOrigin analysis showed a close association between EMPA-related lipid metabolic pathways and gut microbiota alterations, characterized by reduced abundances of Firmicutes and Desulfovibrio and increased abundance of Akkermansia (all P < 0.05). The metabolic homeostasis of ORG mice, especially in lipid metabolism, was disrupted and closely associated with gut microbiota alterations, contributing to the progression of ORG. EMPA treatment improved kidney function and morphology by regulating lipid metabolism through the gut-kidney axis, highlighting a novel therapeutic approach for ORG. NEW & NOTEWORTHY Our study uncovered that empagliflozin (EMPA) potentially protects renal function and morphology in obesity-related glomerulopathy (ORG) mice by regulating the gut-kidney axis. EMPA's reno-protective effects in ORG mice are associated with the lipid metabolism, especially in glycerophospholipid metabolism and the pantothenate/CoA synthesis pathways. EMPA's modulation of gut microbiota appears to be pivotal in suppressing glycerol 3-phosphate and CoA synthesis. The insights into gut microbiota-host metabolic interactions offer a novel therapeutic approach for ORG.

Inulin Supplementation Alleviates Ochratoxin A-Induced Kidney Injury through Modulating Intestinal Microbiota.

Ochratoxin A (OTA) is a prevalent mycotoxin found in feed that causes significant kidney injury in animals. Further investigation was needed to devise strategies for treating OTA-induced kidney damage through the gut-kidney axis. Evidence indicates the crucial role of intestinal microbiota in kidney damage development. Inulin, a dietary fiber, protects kidneys by modulating intestinal microbiota and promoting short-chain fatty acid (SCFA) production. However, its precise mechanism in OTA-induced kidney damage remained unclear. In this study, chickens were orally administered OTA and inulin for 2 weeks to investigate inulin's effects on OTA-induced kidney damage and underlying mechanisms. The alteration of intestinal microbiota, SCFAs contents, and SCFA receptors was further analyzed. Results demonstrated that inulin supplementation influenced intestinal microbiota, increased SCFAs production, and mitigated OTA-induced kidney damage in chickens. The importance of microbiota in mediating inulin's renal protection was further confirmed by antibiotic and fecal microbiota transplantation experiments. Additionally, inulin exhibited antioxidant and anti-inflammatory properties, alleviating NLRP3 inflammasome activation and pyroptosis. In summary, inulin protected chickens from OTA-induced kidney damage, which might provide a potential strategy to mitigate the harmful effects of mycotoxins through prebiotics and safeguard renal health.

Analysis of the microecological mechanism of diabetic kidney disease based on the theory of "gut-kidney axis": A systematic review.

Diabetic kidney disease (DKD) is one of the main microvascular complications of diabetes mellitus, as well as the leading cause of end-stage renal disease. Intestinal microbiota has emerged as a crucial regulator of its occurrence and development. Dysbiosis of the intestinal microbiota can disrupt the intestinal mucosal barrier, abnormal immunological response, reduction in short-chain fatty acid metabolites, and elevation of uremic toxins, all closely related to the occurrence and development of DKD. However, the underlying mechanisms of how intestinal microbiota and its metabolites influence the onset and progression of DKD has not been fully elucidated. In the current review, we will try to summarize the microecological mechanism of DKD by focusing on three aspects: the intestinal microbiota and its associated metabolites, and the "gut-kidney axis," and try to summarize therapies targeted at managing the intestinal microbiota, expecting to provide theoretical basis for the subsequent study of the relationship between intestinal homeostasis and DKD, and will open an emerging perspective and orientation for DKD treatment.

TMAO is involved in kidney-yang deficiency syndrome diarrhea by mediating the “gut-kidney axis”

BackgroundTrimethylamine-N-oxide (TMAO) is a harmful metabolite dependent on the intestinal microbiota and excreted through the kidneys. According to numerous investigations, rich circulation concentrations of TMAO have been linked to kidney and gastrointestinal disorders. Through the “gut-kidney axis” mediated by TMAO, this research attempted to clarify the microbiological causes of kidney-yang deficiency syndrome diarrhea. MethodsAdenine and Folium Sennae were used to create a mouse model of kidney-yang deficiency syndrome diarrhea. 16S rRNA sequencing was used to identify the traits of the intestinal mucosal microbiota. ELISA was used to assess TMAO, transforming growth factor-β1 (TGF-β1), interleukin-1β (IL-1β), and NOD-like receptor thermal protein domain associated protein 3 (NLRP3). Kidney tissue fibrosis was evaluated using Masson's trichrome staining, and immunohistochemical labeling was used to investigate the protein expression of occludin and Zonula Occludens-1(ZO-1) in small intestine tissue. Microbial activity was determined by using fluorescein diacetate (FDA) hydrolysis spectrophotometry. ResultsTMAO showed a positive correlation with NLRP3, IL-1β and TGF-β1, all of which exhibited substantial increases (P < 0.05). Significant renal fibrosis and decreased ZO-1 and occludin expression in small intestine tissues were detected in the model group. The sequencing results revealed alterations in both α and β diversities of small intestinal mucosal microbiota. Elevated TMAO concentrations were potentially associated with increasing Firmicutes/Bacteroidota (F/B) ratios, Streptococcus, Pseudomonas and unclassified Clostridia UCG 014, but with decreasing Rothia and RB41 abundances. ConclusionThis study establishes a link between intestinal microbiota dysbiosis and elevated TMAO concentrations. TMAO can activate inflammatory responses and cytokines, contributing to kidney-yang deficiency syndrome diarrhea via the “gut-kidney axis”. Moreover, TMAO may coincide with disruptions in the intestinal barrier and renal fibrosis. Dysfunction of the “gut-kidney axis” further elevates TMAO levels, perpetuating a vicious cycle.

Establishing the Interrelations of the Laboratory Parameters in the Gut-Kidney Axis in Cats with Signs of Triple Phosphate Urolithiasis

Introduction. Efficient treatment of the feline urolithiasis much depends on the early diagnosis of the disease, however, the diagnostic algorithm of this type of pathology is extremely poor due to the various reasons, in particular, it does not take into account the interrelations in the gut-kidney axis. Analysis of the state of gastrointestinal tract functioning and the composition of the gut microbiota can improve the potential of diagnosing the urolithiasis, predict the risk, improve the prognosis and choose the correct treatment strategy. The aim of this publication is to establish the interrelations of the laboratory parameters in the gut-kidney axis in cats with struvite urolithiasis with the signs of cystolithiasis.Materials and Methods. The objects of the research were the outbred cats with the triple phosphate urolithiasis with the signs of cystolithiasis: 1st experimental group — females; 2nd experimental group — neutered males; the control group — clinically healthy animals of both sexes. The laboratory and clinical examinations of sick animals included: ultrasonography of abdominal organs; macroscopic and biochemical urine tests; microscopy of urine sediment and urine culture test without determination of antibiotic sensitivity; macroscopic, microscopic and simple chemical examinations of freshly excreted feces; bacteriological culture test of rectal flushes without determination of antibiotic sensitivity.Results. In the urine of cats of the experimental groups, under the activity of gram-negative microorganisms Escherichia coli (0.03±0.01×106 CFU (colony forming units) and 1.00±0.03×106 CFU) and gram-positive microorganisms Staphilococcus intermedius (1.05±0.07×106 CFU and 1.00±0.08×107 CFU) there were recorded within the microscope field of view: alkalization, development of hypersthenuria, proteinuria, hypercalciuria, hematuria, including microhematuria and leukocyturia, crystalluria. The results of coprological examinations in sick cats indicated the presence of stercobilin, well-digested muscle fibres, undigested and digested cellulose, extracellular and intracellular starch, as well as impurities of non-food origin (wool). The data of microbiological examinations of feces indicated the growth of Escherichia coli (1.00±0.05×105 CFU and 1.04±0.08×107 CFU). Along with the cystolytiasis, the acoustic shadowing of the gastrointestinal tract organs in the experimental animals revealed the hyperechogenicity of liver capsule and parenchyma and heterogeneity of the pattern.Discussion and Conclusion. The revealed character of the laboratory parameter changes in the experimental animals, such as the increase of protein and creatinine levels in urine and growth of Escherichia coli in feces, proved the existence of the pathogenetic relationship between the urogenital tract lesion caused by the gram-negative microorganisms and the gut microbiota in the gut-kidney axis. The results of our study of the sick animals’ urine indicated on the infection of the urogenital tract with the urease-producing microorganisms, which led to the alkalization of urine and formation of the infection struvite stones. Urolithiasis, in turn, had an impact on the gut microbiome due to the topographic proximity of the urogenital and gastrointestinal tracts: examination of feces in cats of the experimental group had confirmed the disorder of gastrointestinal tract functioning due to dysbiotic processes in the large intestine.

Regulation of kidney fibrosis by ILC3s via a gut-kidney axis.

Regulation of kidney fibrosis by ILC3s via a gut-kidney axis.

The influence of gut microbiota on membranous nephropathy: A two-sample Mendelian randomization study.

Therapeutic approaches that target the gut microbiota may be helpful in the potential prevention and treatment of membranous nephropathy (MN). Several studies demonstrated a correlation between gut microbiota and MN. However, the confounding evidence cannot prove a causal relationship between gut microbiota and MN. The aim of our study is to assess genome-wide association study data for a causal relationship between gut microbiota and MN using a two-sample Mendelian randomization (MR) approach. Inverse variance weighted (IVW) was used as the primary technique to determine the association of genetic variants from gut microbiota and MN patients. Besides, sensitivity analyses confirmed the accuracy of the results. Finally, we applied false discovery rate (FDR) correction to results with IVW < 0.05 during multiple hypothesis testing. The results from IVW estimates indicated that Bacillales exhibited a significant association with MN, acting as a risk factor (OR = 1.52, 95% CI: 1.14 - 2.02, p = 0.005). In addition, our univariable MR results showed that 7 bacterial taxa (Melainabacteria, Butyricicoccus, Catenibacterium, Ruminiclostridium5, RuminococcaceaeUCG003, RuminococcaceaeUCG013, and Gastranaerophilales) had suggestive associations with MN. The sensitivity analysis did not reveal any significant heterogeneity in the instrumental variables or horizontal pleiotropy. Our findings provided causal evidence for the effect of gut microbiota on MN patients and broadened the spectrum of bacterial taxa that might be involved in the pathogenesis of MN. These selected bacterial taxa hold promise as new biomarkers, which may aid in designing targeted therapeutic modalities for MN, improving our comprehension of the gut-kidney axis.

Gut microbiota dysbiosis in hyperuricaemia promotes renal injury through the activation of NLRP3 inflammasome

BackgroundThe prevalence of hyperuricaemia (HUA), a metabolic disorder characterized by elevated levels of uric acid, is on the rise and is frequently associated with renal injury. Gut microbiota and gut-derived uremic toxins are critical mediators in the gut-kidney axis that can cause damage to kidney function. Gut dysbiosis has been implicated in various kidney diseases. However, the role and underlying mechanism of the gut microbiota in HUA-induced renal injury remain unknown.ResultsA HUA rat model was first established by knocking out the uricase (UOX). HUA rats exhibited apparent renal dysfunction, renal tubular injury, fibrosis, NLRP3 inflammasome activation, and impaired intestinal barrier functions. Analysis of 16S rRNA sequencing and functional prediction data revealed an abnormal gut microbiota profile and activation of pathways associated with uremic toxin production. A metabolomic analysis showed evident accumulation of gut-derived uremic toxins in the kidneys of HUA rats. Furthermore, faecal microbiota transplantation (FMT) was performed to confirm the effects of HUA-induced gut dysbiosis on renal injury. Mice recolonized with HUA microbiota exhibited severe renal injury and impaired intestinal barrier functions following renal ischemia/reperfusion (I/R) surgery. Notably, in NLRP3-knockout (NLRP3−/−) I/R mice, the deleterious effects of the HUA microbiota on renal injury and the intestinal barrier were eliminated.ConclusionOur results demonstrate that HUA-induced gut dysbiosis contributes to the development of renal injury, possibly by promoting the production of gut-derived uremic toxins and subsequently activating the NLRP3 inflammasome. Our data suggest a potential therapeutic strategy for the treatment of renal diseases by targeting the gut microbiota and the NLRP3 inflammasome.-txnFZYkVzJbh2g8RkPjrkVideo Graphical

Targeting the Gut-Kidney Axis in Diarrhea with Kidney-Yang Deficiency Syndrome: The Role of Sishen Pills in Regulating TMAO-Mediated Inflammatory Response.

BACKGROUND Sishen Pills (SSPs) are commonly used to treat diarrhea with kidney-yang deficiency syndrome. Trimethylamine-N-oxide (TMAO) is produced through the metabolism of gut microbiota and can participate in diarrhea in kidney-yang deficiency syndrome by mediating the "gut-kidney axis" to transmit inflammatory factors. This study combined network pharmacology with animal experiments to explore whether SSPs can treat diarrhea with kidney-yang deficiency syndrome by affecting the interaction between TMAO and gut microbiota. MATERIAL AND METHODS A mouse model of diarrhea with kidney-yang deficiency syndrome was constructed by using adenine and Folium sennae decoction, and SSP decoction was used for treatment. This study utilized network pharmacology to predict the potential mechanisms of SSPs in treating diarrhea with kidney-yang deficiency syndrome. 16S rRNA high-throughput sequencing was used to analyze gut mucosal microbial characteristics. ELISA was used to measure TMAO, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), interleukin-1ß (IL-1ß), and transforming growth factor-ß1 (TGF-ß1) levels. We performed Masson and immunohistochemical (Occludin, ZO-1) staining of kidney and small intestinal tissues. The fluorescein diacetate (FDA) hydrolysis spectrophotometric method was used to assess the microbial activity in contents of the small intestine. RESULTS Network pharmacology analysis revealed that SSPs can modulate 108 target points involved in the development of diarrhea, including IL-1ß and TNF. The experimental results demonstrated that SSP decoction significantly improved the general behavioral profiles of the mice, and also reduced TMAO, NLRP3, IL-1ß, and TGF-ß1 levels (P<0.05). Correlation analysis revealed significant positive correlations between TMAO concentrations and NLRP3, IL-1ß and TGF-ß1 levels (P<0.05). Pathological analysis revealed improvements in renal fibrosis and increased expression of the Occludin and ZO-1 proteins in intestinal tissue. In the SSP group, there was a significant increase in microbial activity (P<0.001). According to the sequencing results, the characteristic bacteria of the SSP and NR groups included Succinatimonas hippei, uncultured Solirubrobacter sp., and Clostridium tyrobutyricum. Furthermore, TMAO, NLRP3, IL-1ß, and TGF-ß1 were significantly positively correlated (P<0.05) with Succinatimonas hippei and Clostridium tyrobutyricum. By modulating Firmicutes, Succinatimonas hippei, and Clostridium tyrobutyricum, SSP decoction lowers TMAO levels to alleviate diarrhea with kidney-yang deficiency syndrome. CONCLUSIONS TMAO likely plays a significant role in the "gut-kidney axis" of diarrhea with kidney-yang deficiency syndrome. By adjusting gut microbiota to reduce the inflammatory response that is transmitted through the "gut-kidney axis" as a result of elevated TMAO levels, SSP decoction can alleviate diarrhea with kidney-yang deficiency syndrome.

Investigation of the human-gut-kidney axis by fecal proteomics, highlights molecular mechanisms affected in CKD

ObjectiveThe interplay of gut microbiota with the kidney system in chronic kidney disease (CKD), is characterized by increased concentrations of uric acid in the gut, which in turn, may increase bacterial uricase activity and may lead to the generation of uremic toxins. Nevertheless, knowledge on these underlying bidirectional molecular mechanisms is still limited. MethodsIn this exploratory study, proteomic analysis was performed on fecal samples, targeting to investigate this largely unexplored biological material as a source of information reflecting the gut-kidney axis. Specifically, fecal suspension samples from patients with CKD1 (n = 12) and CKD4 (n = 17) were analysed by LC-MS/MS, using both the Human and Bacterial UniProt RefSeq reviewed databases. ResultsThis fecal proteomic analysis collectively identified 701 human and 1011 bacterial proteins of high confidence. Differential expression analysis (CKD4/CKD1) revealed significant changes in human proteins (n = 8, including proteins such as galectin-3-binding protein and prolactin-inducible protein), that were found to be associated with inflammation and CKD. The differential protein expression of pancreatic alpha-amylase further suggested plausible reduced saccharolytic fermentation in CKD4/CKD1. Significant changes in bacterial proteins (n = 9, such as glyceraldehyde-3-phosphate dehydrogenase and enolase), participating in various carbohydrate and metabolic pathways important for the synthesis of butyrate, in turn suggested differential butyrate synthesis in CKD4/CKD1. Further, targeted quantification of fecal pancreatic alpha-amylase and butyrate in the same fecal suspension samples, supported these hypotheses. ConclusionCollectively, this exploratory fecal proteomic analysis highlighted changes in human and bacterial proteins reflecting inflammation and reduced saccharolytic fermentation in CKD4/CKD1, plausibly affecting the butyrate synthesis pathways in advanced stage kidney disease. Integrative multi-omics validation is planned.

#1620 Association of dietary live microbe intake with chronic kidney disease based on baseline characteristics of national population: NHANES 2011-2018

Abstract Background and Aims The gut microbiota plays a crucial role in a variety of diseases, including chronic kidney disease (CKD). The gut-kidney axis is mediated through metabolism dependent pathways. The relationship between CKD and the dietary consumption of live microbes has not been explicitly studied. Probiotic food intake may play a beneficial role in human health including the gut microbiota. However, in addition to probiotic foods, live micro-organisms are also found in other food products, such as raw vegetables and fruits. In this study, we adjusted for the potential association between dietary live microbiome intake and chronic kidney disease (CKD) in different baseline characteristics, including kidney function status. Method A total of 22,039 subjects were included in the study. We used data from the US National Health and Nutrition Examination Survey 2011-2018. Based on a 2-day 24-hour dietary recall, the dietary intake of the live microbiome was adjusted and the participants were categorized into three groups: low (&amp;lt;104 CFU/g), medium (104–107 CFU/g), or high (&amp;gt;107 CFU/g) dietary intake of live microbes, according to the classification system for the dietary intake of live microbes and participants’ 24-hour dietary recall data. Low intake was used as a reference. Stage 3 CKD with high risk of progression was defined by a combination of estimated glomerular filtration rate (GFR-EPI &amp;lt;60 mL/min/1.73 m2) and urinary albumin-to-creatinine ratio (uACR &amp;gt;30 mg/g was defined as microalbuminuria). CKD was defined by a combination of GFR-EPI &amp;lt;60 mL/min/1.73 m2 or uACR, &amp;gt;30 mg/g. Albuminuria was defined as uACR &amp;gt;300 mg/g. The analyses used weighted logistic regression models (crude model and first, adjusted for age, gender, race, education and second, adjusted for hypertension, diabetes, total cholesterol level, BMI, hemoglobin level, total calorie intake, GFR and serum creatinine level). Results After model adjustment (Model 2, p&amp;lt; 0.0001), women in the medium dietary live microbe intake group had a low prevalence of stage 3 CKD with high risk of progression in contrast to those in the low dietary live microbiome intake group (OR: 0.913, 95% Cl: 0.63-1.32, p&amp;lt; 0.01), between high and low group (OR: 0.333, 95% Cl: 0.13-0.86, p&amp;lt; 0.01). However there was no significant association in men. In model 2, patients in the medium dietary live microbiome intake group had a low prevalence of microalbuminuria in contrast to those in the low dietary live microbiome intake group (OR: 0.789, 95% Cl: 0.63-0.98, p&amp;lt; 0.05). In model 2, we also found the significant association with albuminuria between high and low (OR 0.784, 95% Cl: 0.63-0.98, p&amp;lt; 0.05), medium and low (OR: 0.572, 95% Cl: 0.33-0.98, p&amp;lt; 0.05) dietary live microbiome intake patient groups. In model 2, those in the medium dietary live microbe intake group had a low prevalence of CKD in contrast to those in the low dietary live microbiome intake group (OR: 0.896, 95% Cl: 0.82-0.98) p&amp;lt; 0.01), but there was no significant association between the high and low dietary live microbiome intake groups. Conclusion In this study, a medium or high dietary live microbiome intake was associated with a low prevalence of stage 3 CKD with ahigh risk of progression in women. A medium dietary live microbiome intake was associated with a low prevalence of chronic kidney disease or microalbuminuria in the population. A medium or high dietary live microbiome intake was associated with a low prevalence of albuminuria. A medium dietary live microbiome intake was associated with a low prevalence of microalbuminuria.