Targeting Lactobacillus johnsonii to reverse chronic kidney disease

Tanshinone IIA reduces tubulointerstitial fibrosis by suppressing GSDMD-mediated pyroptosis

CONTEXT

Tanshinone IIA (Tan IIA), a bioactive compound derived from the traditional Chinese herb Salvia miltiorrhiza (Family Lamiaceae, Authority Bunge), is well-known for its protective effects in various kidney diseases. However, its role in obstructive nephropathy has not been thoroughly investigated.

OBJECTIVE

This study aimed to explore the protective effects of Tan IIA in a mouse model of unilateral ureteral obstruction (UUO) and to elucidate the cellular and molecular mechanisms underlying these effects.

MATERIALS AND METHODS

Gasdermin D (GSDMD) knockout mice and their wild-type (WT) littermates underwent UUO surgery, with Tan IIA treatment administered 24 h prior. Human proximal tubular cells (HK-2 cells) were treated with TGF-β1 to induce fibrosis (50 ng/mL for 24 h), followed by Tan IIA treatment (5 μM) for an additional 3 h.

RESULTS

Tan IIA significantly reduced the expression of extracellular matrix (ECM) components, including collagen I, α-smooth muscle actin (α-SMA), vimentin and fibronectin, in UUO mice. Tan IIA attenuated GSDMD-mediated pyroptosis. However, in GSDMD knockout mice subjected to UUO, the protective effects of Tan IIA on ECM gene expression and collagen deposition in the tubular interstitium were reduced. In vitro studies showed that Tan IIA reduced GSDMD activation and fibronectin protein expression in HK-2 cells.

DISCUSSION AND CONCLUSIONS

Tan IIA may mitigate GSDMD-mediated pyroptosis in renal tubular epithelial cells (RTECs) and reduce kidney fibrosis, highlighting its potential as a therapeutic strategy to prevent the progression of kidney disease after ureteral obstruction.

Targeted modulation of intestinal barrier and mucosal immune-related microbiota attenuates IgA nephropathy progression

IgA nephropathy (IgAN) is related to the balance of gut microbiota. However, it is unclear whether changes in the gut microbiota can cause IgAN or attenuate its progression. This study employed IgAN and human microbiota-associated (HMA)-IgAN models to investigate the impact of IgAN on gut microbiota alteration and the mechanisms by which gut microbiota might trigger IgAN. Furthermore, this study examined the effects of chitooligosaccharides (COS) and COS formulation (COSF) with microbiota-targeting function on enhancing intestinal barrier and renal functions. These results revealed that IgAN led to a reduction in α-diversity and structural alterations in the gut microbiota, characterized by an increase in Shigella sonnei, Streptococcus danieliae, Desulfovibrio fairfieldensis, and a decrease in Bifidobacterium pseudolongum and Clostridium leptum. There was also an imbalance in intestinal B-cell immunity and a decrease in the level of tight junction proteins (ZO-1 and Occludin). Intestinal barrier and mucosal immune-related microbiota (Clostridium leptum, unclassified Lachnospiraceae NK4Al36 group, unclassified Clostridia vadinBB60 group, unclassified Oscillospiraceae, and unclassified Roseburia) were enriched through targeted modulation with COS/COSF, enhancing intestinal ZO-1 expression and reducing APRIL/BAFF overexpression, thereby reducing renal damage in IgAN. In conclusion, this study clarified the kidney-gut crosstalk between gut microbiota and IgAN, providing scientific evidence for developing microbiota-targeted food interventions to improve IgAN outcomes.

Polycyclic aromatic hydrocarbon-aryl hydrocarbon receptor signaling regulates chronic inflammation in lung-gut axis

Polycyclic aromatic hydrocarbons (PAHs) are broadly identified in environmental pollutants and also formed during the heat processing of meat, including grilling, roasting, smoking, and frying, particularly at high temperatures. Besides, the PAHs influence inflammatory response through activation of aryl hydrocarbon receptor (AhR) signaling. Recently, the role of the PAHs/AhR axis in inflammatory diseases has attracted major attention in the regulation of lung function, gut barrier function, and systemic inflammation. Many experiments have been conducted to determine the role of the PAHs/AhR/cytochrome P450 1A1 signaling activation on elevation of inflammation in the lung-gut axis. In contrast, several dietary AhR ligands can improve inflammatory function by modulating the AhR signaling, thereby strengthening the intestinal barrier. This review includes the pivotal roles of xenobiotic and diet-derived AhR ligands in the regulation of chronic lung diseases and systemic inflammation and their relevance in the lung-gut axis.

Cardiorenal syndrome: clinical diagnosis, molecular mechanisms and therapeutic strategies

As the heart and kidneys are closely connected by the circulatory system, primary dysfunction of either organ usually leads to secondary dysfunction or damage to the other organ. These interactions play a major role in the pathogenesis of a clinical entity named cardiorenal syndrome (CRS). The pathophysiology of CRS is complicated and involves multiple body systems. In early studies, CRS was classified into five subtypes according to the organs associated with the vicious cycle and the acuteness and chronicity of CRS. Increasing evidence shows that CRS is associated with a variety of pathological mechanisms, such as haemodynamics, neurohormonal changes, hypervolemia, hypertension, hyperuraemia and hyperuricaemia. In this review, we summarize the classification and currently available diagnostic biomarkers of CRS. We highlight the recently revealed molecular pathogenesis of CRS, such as oxidative stress and inflammation, hyperactive renin‒angiotensin‒aldosterone system, maladaptive Wnt/β-catenin signalling pathway and profibrotic TGF‒β1/Smad signalling pathway, as well as other pathogeneses, such as dysbiosis of the gut microbiota and dysregulation of noncoding RNAs. Targeting these CRS-associated signalling pathways has new therapeutic potential for treating CRS. In addition, various chemical drugs, natural products, complementary therapies, blockers, and agonists that protect against CRS are summarized. Since the molecular mechanisms of CRS remain to be elucidated, no single intervention has been shown to be effective in treating CRS. Pharmacologic therapies designed to block CRS are urgently needed. This review presents a critical therapeutic avenue for targeting CRS and concurrently illuminates challenges and opportunities for discovering novel treatment strategies for CRS.

Saliva urea nitrogen for detection of kidney disease in adults: A meta-analysis of diagnostic test accuracy

BACKGROUND

Kidney disease affects millions globally, especially in low and middle-income countries where access to diagnostic testing is limited. Saliva urea nitrogen (SUN) has been proposed as a simple, non-invasive alternative to traditional serum-based diagnostics.

OBJECTIVE

This study aimed to evaluate the diagnostic accuracy of SUN for detecting kidney disease in adults through a systematic review and meta-analysis.

METHODS

This review adhered to the PRISMA-DTA guidelines. A comprehensive search of five databases was conducted without language or date restrictions. Study quality was assessed using the QUADAS-2 tool. STATA version 17 was used for analysis. A random-effects model was used to estimate pooled sensitivity, specificity, and diagnostic odds ratios (DOR). Subgroup analysis was conducted based on the reference test used (serum creatinine or blood urea nitrogen). Heterogeneity was assessed using the I² statistic, and meta-regression explored sources of heterogeneity.

RESULTS

Seven studies (n = 1,933) met the inclusion criteria. In the serum creatinine (sCr) subgroup (2 studies), SUN showed pooled sensitivity of 0.44 (95% CI: 0.38-0.49), specificity 0.96 (95% CI: 0.95-0.98), DOR 18.89 (95% CI: 15.19-23.57), and AUC ~ 0.90. In the blood urea nitrogen (BUN) subgroup (5 studies), sensitivity was 0.83 (95% CI: 0.69-0.91), specificity 0.88 (95% CI: 0.78-0.94), DOR 37 (95% CI: 15-91), and AUC 0.93. Heterogeneity was moderate in the BUN subgroup (bivariate I² = 51%), with 42% of variability attributed to threshold effects. Meta-regression identified study country (p = 0.01), and reference test used (p = 0.02) as contributors to heterogeneity in sensitivity, while comorbidity (p = 0.001) significantly affected specificity.

CONCLUSION

SUN shows high diagnostic specificity and a good overall accuracy, particularly when compared to BUN, and may serve as a practical non-invasive screening tool in low- resource settings. While heterogeneity was present, SUN remains a promising diagnostic alternative and warrants further validation in diverse clinical populations.

Balancing Stone Prevention and Kidney Function: A Therapeutic Dilemma

Managing nephrolithiasis in chronic kidney disease (CKD) poses a therapeutic challenge: preventing stone recurrence while preserving kidney function. Standard urological interventions and preventive strategies, such as high fluid intake, thiazides, and potassium citrate, cut recurrence by 50-60% in healthy kidneys but risk fluid overload, hyperkalemia, and diminished efficacy in CKD as glomerular filtration rate (GFR) declines. Often, stone prevention and CKD care are addressed separately, leaving clinicians without unified guidance for this rising patient group. This review explores the bidirectional relationship between nephrolithiasis and CKD, integrating pathophysiology and therapeutic strategies into a practical, decision-oriented framework. It offers tailored interventions based on GFR category, stone type, and comorbid conditions, emphasizing the potential for dual-purpose therapies. Going beyond previous reviews, it connects clinical practice with existing research gaps, offering tools to balance outcomes and guide future studies.

Tryptophan Indole Derivatives: Key Players in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a complex clinical syndrome characterized by insulin resistance and associated with abnormal amino acid metabolism. Tryptophan is an aromatic dietary amino acid that affects T2DM by regulating glycolipid metabolism and insulin resistance. When tryptophan reaches the intestine, it is converted by gut microbiota and tryptophanase into indole derivatives such as indoleacetic acid, indolepropionic acid, and indolealdehyde. These indole derivatives may enhance insulin sensitivity, stimulate insulin secretion, and exert functions such as lowering blood glucose, regulating hepatic oxidative stress, reducing intestinal inflammation, and improving islet cell morphology by acting on the aryl hydrocarbon receptor (AHR) or Pregnane X receptor (PXR). In summary, this review aims to examine the interactions between tryptophan indole derivatives and T2DM thoroughly, elucidate potential therapeutic approaches, and pinpoint areas for further research.

Huangkui capsules regulate tryptophan metabolism to improve diabetic nephropathy through the Keap1/Nrf2/HO-1 pathway

Background

Diabetic nephropathy (DN) is a serious complication of diabetes and one of the leading causes of end-stage renal disease. Huangkui capsule (HKC), a traditional Chinese patent medicine, is widely used in clinical practice for the treatment of chronic glomerulonephritis. However, the therapeutic effects and underlying mechanisms of HKC in DN remain poorly understood.

Methods

DN was induced in db/db mice, which were randomly divided into the DN, HKC-L, HKC-H and IRB groups, and db/m mice served as the Control group. Biochemical indices of blood and urine samples from the mice were measured, and HE staining, Masson staining and PAS staining were used to verify the anti-DN effect of HKC. The levels of ROS and the expression of Nrf2 pathway-related proteins and mRNAs were detected. Metabonomic analysis was used to investigate the role of tryptophan metabolism in the regulation of DN by HKC. HK-2 cells were used to establish a model of high-glucose (HG) injury in vitro, and HKC treatment was given for supplementary verification. Sarpogrelate hydrochloride (SH) combined with HKC, a 5-HT2AR inhibitor, was used to verify the effect of the 5-HT pathway in an in vitro model.

Results

Treatment with HKC significantly inhibited the increase in blood glucose and Urinary albumin/creatinine ratio (UACR), improved kidney injury signs in mice, reduced the level of ROS and improved oxidative stress injury through the Keap1/ Nrf2/HO-1 pathway. Metabonomic analysis revealed that tryptophan metabolism is involved in the process by which HKC improves DN, and HKC can regulate the 5-HT pathway to improve the renal injury by oxidative stress regulation. HKC treatment also significantly improved the renal and oxidative stress injuries in HG HK-2 cell model through the Nrf2 pathway in vitro. SH administration revealed that inhibiting 5-HT2AR could significantly inhibit the synthesis of 5-HT and improve the renal injury induced by HG.

Conclusion

Our study demonstrate that HKC can inhibit kidney injury and oxidative stress injury in db/db mice and HK-2 cells by regulating tryptophan metabolism and the Keap1/Nrf2/HO-1 pathway, which provides new insight for the clinical use of HKC for treatment of DN.

Poricoic Acid A Protects Against High-Salt-Diet Induced Renal Fibrosis by Modulating Gut Microbiota and SCFA Metabolism

The gut microbiota serves a critical role in the development of chronic kidney disease (CKD). High salt intake has been known to cause hypertension and CKD, however, it is still unclear whether it also affects gut microbiota in CKD mice. This article first studied the salutary effects of poricoic acid A (PAA), a natural triterpenoid from Poria cocos, on high salt diet-induced CKD in kunming mice. It was demonstrated that the administration of PAA by oral gavage (20 mg/kg·bw) could decrease the kidney index and urinary protein levels, prevent the kidney tubule dilated and renal fibrosis, and activated the expression of adenosine monophosphate-activated protein kinase (AMPK) in kidney. In addition, 16 S rRNA-based microbiota analysis indicated that PAA ameliorated intestinal microbiota dysbiosis caused by high-salt-diet and particularly enhanced the abundances of beneficial microbiota, such as Lactobacillus and Akkermansia, followed by a significant increase in the levels of short-chain fatty acids (SCFAs). Meanwhile, PAA improved intestinal barrier damage and increased the expression of intestinal tight junction protein. In summary, these experiments demonstrated that PAA enhances the growth of probiotics while decreasing the abundance of endotoxin-producing bacteria. This dual action contributes to the amelioration of intestinal mucosal barrier dysfunction and mitigates the impact of a high-salt diet on renal interstitial fibrosis in mice.

Perturbed gut microbiota and serum metabolites are associated with progressive renal fibrosis

Introduction

The intricate pathogenesis of renal fibrosis necessitates identifying biomarkers at various stages to facilitate targeted therapeutic interventions, which would enhance patient survival rates and significantly improve prognosis.

Methods

We investigated the changes in gut microbiota and serum metabolites during the early, middle, and late stages of renal fibrosis in rats using 16S rDNA sequencing and UPLC-QTOF/MS-based metabolomics.

Results

We identified 5, 21, and 14 potential gut microbial markers and 19, 23, and 31 potential metabolic markers in the MOD1, MOD2, and MOD4 groups, respectively. Bifidobacterium was identified as a shared microbial marker between the MOD1 and MOD2 groups; Prevotellaceae_NK3B31_group and Bacteroides were identified as shared microbial markers between the MOD2 and MOD4 groups. The pathways of arachidonic acid metabolism and retinol metabolism were found to play a significant role in the modulation of renal fibrosis at 1, 2, and 4 weeks. Notably, the metabolic biomarkers 8,9-EET and 5(S)-HPETE within these pathways emerged as critical determinants influencing renal fibrosis.

Discussion

Our findings demonstrated that the severity of renal fibrosis is associated with dysbiosis of the gut microbiota and alterations in serum metabolites.

Fecal Calprotectin as a Prognostic Biomarker for Mortality and Renal Outcomes in Chronic Kidney Disease

BACKGROUND/OBJECTIVES

Fecal calprotectin (FC) is a biomarker of intestinal inflammation widely used in the assessment of gastrointestinal disorders. However, its role in chronic kidney disease (CKD) remains unclear. Given the growing recognition of the gut-kidney axis in CKD pathophysiology, this study aimed to investigate the association between FC levels, systemic inflammation, renal outcomes, and mortality in CKD patients.

METHODS

We enrolled a total of 515 CKD patients who underwent fecal calprotectin measurement between 2016 and 2023. After applying the exclusion criteria (inflammatory bowel disease, ongoing renal replacement therapy, or incomplete laboratory data), 260 patients were included in the final analysis and stratified into low-FC (<102 μg/g, n = 130) and high-FC (≥102 μg/g, n = 130) groups based on the median FC value. Factors associated with kidney disease progression and patient survival were analyzed.

RESULTS

Patients in the high-FC group (≥102 μg/g) were significantly older (72.8 ± 14.63 vs. 64.02 ± 18.15 years, p < 0.0001) and had a higher prevalence of diabetes mellitus (55.38% vs. 42.31%, p = 0.0349), heart failure (21.54% vs. 7.69%, p = 0.0016), and history of acute kidney injury (33.85% vs. 18.46%, p = 0.0048). Elevated FC was independently associated with increased mortality risk (hazards ratio [HR] 1.658, 95% confidence interval [CI] 1.034-2.658, p = 0.0357) with higher mortality rates (48.36 vs. 18.46 per 100,000 person-years). Subgroup analyses revealed stronger associations between FC and mortality in males (HR 2.160, 95% CI 1.046-4.463, p = 0.0375), elderly patients (≥75 years) (HR 2.122, 95% CI 1.209-3.725, p = 0.0088), and non-diabetic patients (HR 2.487, 95% CI 1.141-5.421, p = 0.0219). While FC was not significantly associated with end-stage kidney disease (ESKD) progression (odds ratio [OR] 1.289, 95% CI 0.455-3.650, p = 0.6323), higher FC levels paradoxically predicted slower estimated glomerular filtration rate (eGFR) decline (OR 2.763, 95% CI 1.139-6.699, p = 0.0245). Combined analysis revealed patients with both elevated FC and high-sensitivity C-reactive protein (hs-CRP) had the highest mortality risk (HR 3.504, 95% CI 1.163-10.554, p < 0.0001) compared to those with low levels of both markers.

CONCLUSIONS

FC is a potential prognostic biomarker for mortality in CKD patients, independently of traditional inflammatory markers. Further research is warranted to elucidate the mechanisms underlying its paradoxical relationship with renal outcomes and its potential role in risk stratification and therapeutic targeting in CKD.

Metabolomic profiling of adenine-induced CKD: pathway interconnections and kidney injury

Chronic kidney disease (CKD) is acknowledged as one of the largest public health problems in the world, characterized by a complex and diverse pathogenesis. Adenine-induced CKD, a classical model with multiple injury mechanisms, has been extensively employed in CKD research. However, the complete elucidation of the mechanisms underlying adenine-induced CKD remains elusive. In this study, the impacts of adenine (200 mg/kg/day) intake on the urine metabolome of rats were initially investigated using non-targeted metabolomics, and then targeted metabolomics was used to quantitatively verify key metabolites on crucial metabolic pathways. Interestingly, the interconnectedness of two significant pathways was discovered and validated through molecular biology techniques. The results found that adenine can cause significant perturbations in purine metabolism and the biosynthetic pathways of phenylalanine, tyrosine, and tryptophan. Subsequent targeted metabolomic analysis revealed a significant reduction in amino acid and hypoxanthine and creatinine levels in the kidneys of CKD rats, accompanied by an increase in xanthine level. Further analysis found that purine pathway can increase ROS production and affect the level of aromatic amino acid transporter SLC7A5, thus influencing the biosynthesis pathway of phenylalanine, tyrosine and tryptophan, ultimately contributing to kidney injury. This discovery provides offers novel insights into the underlying pathological mechanism of adenine-induced CKD. The development of chronic kidney disease is induced by multiple pathways of aromatic amino acid metabolism and purine metabolism.

Poria cocos: traditional uses, triterpenoid components and their renoprotective pharmacology

Poria cocos and its surface layer of Poria cocos (Schw.) Wolf (Polyporaceae), are used in traditional Chinese medicine for its diuretic and renoprotective effects. Phytochemical studies have shown that lanostane and 3,4-seco-lanostane tetracyclic triterpenoids are the main components of P. cocos and its surface layer. Accumulating evidence shows that triterpenoid components in P. cocos and its surface layer contribute to their renoprotective effect. The surface layer of P. cocos showed a stronger diuretic effect than P. cocos. The ethanol extract of the surface layer and its components improved acute kidney injury, acute kidney injury-to-chronic kidney disease transition and chronic kidney disease such as diabetic kidney disease, nephrotic syndrome and tubulointerstitial nephropathy, and protected against renal fibrosis. It has been elucidated that P. cocos and its surface layer exert a diuretic effect and improve kidney diseases through a variety of molecular mechanisms such as aberrant pathways TGF-β1/Smad, Wnt/β-catenin, IκB/NF-κB and Keap1/Nrf2 signaling as well as the activation of renin-angiotensin system, matrix metalloproteinases, aryl hydrocarbon receptor and endogenous metabolites. These studies further confirm the renoprotective effect of P. cocos and its surface layer and provide a beneficial basis to its clinical use in traditional medicine.

Lactobacillus johnsonii Generates Cyclo(pro-trp) and Promotes Intestinal Ca2+ Absorption to Alleviate CKD-SHPT

Patients with chronic kidney disease (CKD) are at a high risk of developing secondary hyperparathyroidism (SHPT), which may cause organ dysfunction and increase patient mortality. The main clinical interventions for CKD-SHPT involve calcium supplements to boost absorption, but ineffective for some patients, and the reasons remain unclear. Here, CKD mice are divided into high and low groups based on intact parathyroid hormone (iPTH) levels. The high group exhibits significant changes in gut microbes, including a decrease in Lactobacillus, an increase in parathyroid hyperplasia, and a decrease in intestinal calcium. Fecal microbiota transplantation and L. johnsonii colonization indicate a link between gut microbes and CKD-SHPT. Clinically, higher L. johnsonii levels are correlated with milder hyperparathyroidism CKD-SHPT. The receiver operating characteristic (ROC) curve for L. johnsonii abundance and surgical risk is 0.81, with the calibration curve confirming predictive accuracy, and decision curve analysis revealing good clinical applicability. In vivo and in vitro experiments show that cyclo(pro-trp) enhance calcium inflow and lower iPTH levels in intestinal epithelial cells via a calcium-sensing receptor and transient receptor potential vanilloid 4 pathways. This study identified the crucial role of L. johnsonii in CKD-SHPT, unveiling a new mechanism for calcium imbalance and offering novel strategies for SHPT treatment and drug development.

Association between exposure to per- and polyfluoroalkyl substances and kidney function: a population study

Background

The relationship between per- and polyfluoroalkyl substances (PFAS) and kidney function markers remains uncertain.

Methods

We used PFAS detection data from 5,947 adults in NHANES 2005-2012. We employed multivariable linear regression models to examine associations between PFAS and estimated glomerular filtration rate (eGFR), urine creatinine (UCR), urine albumin (UAL), and urine albumin/creatinine ratio (UACR). To capture non-linear trends, restricted cubic splines were applied. The WQS (weighted quantile sum) and Q-gcomp (quantile g computation) models were used for the mixture analysis. Subgroup analyses were conducted to explore potential interactions.

Results

Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), 2-(N-methyl-perfluorooctane sulfonamido) acetic acid (N-MEFOSAA), and perfluorononanoic acid (PFNA) were negatively related to eGFR (β = -2.04, 95% CI = -2.85, -1.23; β = -0.97, 95% CI = -1.78, -0.16; β = -1.50, 95% CI = -2.24, -0.76; β = -0.49, 95% CI = -1.25, 0.27; β = -0.68, 95% CI = -1.46, 0.10). PFOA and PFOS were positive associated with UCR (β = 10.61, 95% CI = -1.89, 23.11; β = 12.98, 95% CI = 0.56, 25.41). PFOA, PFOS, PFHxS, PFNA, and PFUA were negatively related to UAL (β = -0.53, 95% CI = -0.73, -0.32; β = -0.39, 95% CI = -0.59, -0.18; β = -0.59, 95% CI = -0.78, -0.40; β = -0.42, 95% CI = -0.65, -0.19; β = -0.04, 95% CI = -0.22, 0.14). PFDA, PFOA, PFOS, PFHxS, and PFNA are significantly inversely associated with UACR (β = -0.01, 95% CI = -0.16, 0.14; β = -0.52, 95% CI = -0.69, -0.35; β = -0.50, 95% CI = -0.67, -0.33; β = -0.49, 95% CI = -0.64, -0.33; β = -0.27, 95% CI = -0.44, -0.10). Nonlinear relationships were found between PFAS and all kidney function indicators. Mixed PFAS exposure showed a negative association with eGFR, UAL and UACR, while showed a positive relationship with UCR. Interactions between PFASs and most subgroups were observed.

Conclusion

Our study revealed significant associations between PFAS exposure and various kidney function indicators. These findings provide an epidemiological perspective on how PFAS may lead to kidney dysfunction.

5-aminolaevulinic acid with sodium ferrous citrate alleviated kidney injury and fibrosis in a unilateral ureteral obstruction model

PURPOSE

This study aimed to investigate the potential therapeutic effects of 5-aminolaevulinic acid (5-ALA) combined with sodium ferrous citrate (SFC) on kidney injury and fibrosis in a mouse model of unilateral ureteral obstruction (UUO)-induced chronic kidney disease (CKD).

METHODS

A murine UUO model was used to mimic human CKD. The mice received daily intragastric administration of 5-ALA/SFC for 7 and 14 consecutive days. Serum creatinine (Cr) and blood urea nitrogen (BUN) levels and histological evaluations were performed to assess the renal function parameters underlying 5-ALA/SFC treatment in the UUO model. Differentially expressed genes (DEGs) were analyzed by RNA sequencing (RNA-Seq), and the results were validated by quantitative real-time PCR (qRT-PCR). The severity of renal fibrosis was evaluated using Sirius red and Masson's trichrome (MT) staining techniques, while the expression of fibrosis-related genes was examined using western blotting and immunohistochemistry.

RESULTS

Our findings demonstrated that 5-ALA/SFC treatment improved UUO-induced renal dysfunction, attenuated tubular damage, and significantly reduced serum Cr and BUN levels as well as the mRNA expression and secretion of pro-inflammatory and programmed cell death-related cytokines in kidney tissues. Furthermore, 5-ALA/SFC suppressed renal tissue fibrosis and downregulated the mRNA and protein expression of fibrosis-related genes. Notably, treatment with 5-ALA/SFC led to the significant upregulation of protein expression levels of PPAR gamma-coactivator-1α (PGC-1α), indicating its role in inhibiting inflammation and fibrosis through the activation of the PGC-1α signaling pathway.

CONCLUSION

5-ALA/SFC exhibits renoprotective effects in UUO-induced CKD by attenuating inflammation, cell death, and suppressing renal fibrosis. These findings suggest a specific renal protective mechanism for 5-ALA/SFC, highlighting its potential as a novel therapeutic agent for human CKD treatment.

Lactobacillus paracasei Activates the KDM3A/VAMP1 Axis to Induce Autophagy in Renal Tubular Epithelial Cells in Chronic Kidney Disease

Chronic kidney disease (CKD) is anticipated to be the fifth cause of global death by 2040 due to the lack of therapeutic tools currently. Lactobacillus paracasei (L. paracasei) isolated from artisanal fermented beverages has been implicated to have health-promoting properties. This study was designed to investigate the effects of L. paracasei on the mechanisms underlying renal injury regulation during CKD. A mouse CKD model was developed by 5/6 nephrectomy, and a fibrotic cell model was induced on human kidney-2 (HK-2) cells using TGF-β1. L. paracasei alleviated renal injury in CKD mice and TGF-β1-induced inflammatory and fibrotic injury in HK-2 cells. L. paracasei exerted in vitro and in vivo benefits by inducing lysine-specific demethylase 3A (KDM3A), and the knockdown of KDM3A markedly attenuated the therapeutic benefit of L. paracasei. KDM3A activated vacuole membrane protein 1 (VMP1) by removing the H3K9me1/2 modification on its promoter. L. paracasei activated autophagy to mitigate renal damage, which was compromised by the autophagy inhibitor 3-MA, allowing renal damage to intensify. Taken together, L. paracasei activates KDM3A expression and further activates VMP1 expression by removing inhibitory H3K9me1/2 modification on the VMP1 promoter to alleviate CKD by activating autophagy in renal tubular epithelial cells.

Native potential probiotics and postbiotics improve the gut-kidney axis by the modulation of autophagy signaling pathway

The gut-kidney axis is the bidirectional relationship between the gut microbiota and the kidney function. Chronic inflammatory responses can impair kidney function and probiotics and postbiotics agents can have positive effects on gut health and kidney function by modulating inflammation through affecting autophagy signaling pathway. The aim of the current study was to evaluate the properties of our probiotic and postbiotics to improve kidney health by focusing the autophagy signaling pathway. The probiotic and postbiotics of four Lactobacillus and two Bifidobacterium strains were selected. Dextran sulfate sodium induced colitis in mice, and probiotics and postbiotics treatments were accomplished in animal experiment. A qPCR assay was performed to assess the gene expression involved in the autophagy process in the kidney. In contrast to the dextran sulfate sodium group, both the probiotic and postbiotics cocktails exhibited the capacity to inhibit colitis-associated indicators. Of note, the postbiotics cocktails demonstrated a greater efficacy in preventing colitis-related indicators and also it could display a more pronounced effect in upregulating autophagy-related genes. Our native potential probiotics and postbiotics can be able to reduce gut inflammation and cope with kidney inflammation by triggering autophagy signaling pathway through the considerable impact on gut-organ axis. There is an encouraging concept about the anti-inflammatory effects of our probiotics and postbiotics cocktails with least side effects as a supplementary treatment not only in the gut, but also in the other organs particularly kidneys.

Aryl hydrocarbon receptor (AHR) and nuclear factor erythroid-derived 2-like 2 (NRF2): An important crosstalk in the gut-liver axis

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, mainly involved in detoxification. However, in the intestine, metabolites derived from the diet, which are converted by a wide range of bacteria can also activate the AHR. This intestinal AHR activation plays a key role in maintaining the gut barrier by, for example, upregulating antimicrobial peptides and anti-inflammatory cytokines. Since the gut barrier influences the gut-liver axis by regulating the leaking of metabolites, bacteria, and endotoxins into circulation and particularly into the liver, the AHR is a key factor in the gut-liver axis. Vice versa, certain liver pathologies also influence the gut microbiome, thereby altering bacteria-derived activation of the AHR. Additionally, bile acids can impact the gut via the liver and thereby also affect the AHR. The aryl hydrocarbon receptor (AHR) interacts with several molecular factors, one of which is the nuclear factor erythroid-derived 2-like 2 (NRF2), a transcription factor primarily associated with regulating antioxidant stress responses. The interplay between AHR and NRF2 has been investigated in the context of various diseases; this review highlights the significance of this interaction within the framework of the gut-liver axis.

Network pharmacology and multi-omics validation of the Jianpi-Yishen formula in the treatment of chronic kidney disease

Objective

Chronic kidney disease (CKD) is a major global health problem. In clinical practice, the Chinese patent herbal medicine Jianpi-Yishen (JPYS) formula is commonly used to treat CKD. However, the molecular mechanisms by which JPYS targets and modulates the host immune response remain unclear.

Methods

This study utilized network pharmacology, RNA sequencing (RNA-seq), and metabolic analyses using in vivo and in vitro models to investigate the impact of the JPYS formula on inflammation and the immune system. Specifically, the study focused on macrophage polarization and metabolic changes that may slow down the progression of CKD.

Results

A total of 14,946 CKD-related targets were identified from the GeneCards and Online Mendelian Inheritance in Man (OMIM) databases through network pharmacology analyses. 227 potential targets of the JPYS formula were predicted using the TCMSP database. Additionally, network diagram demonstrated that 11 targets were associated with macrophage activity. In vivo studies indicated that the JPYS formula could reduce blood urea nitrogen and serum creatinine in adenine-induced CKD rats. Furthermore, the formula inhibited inflammatory damage and abnormal macrophage infiltration in this CKD model. RNA-seq, proteomic and metabolic analyses identified the regulation of amino acid metabolism by betaine, specifically referring to glycine, serine, and threonine metabolism, as a key target of the JPYS formula in slowing the progression of CKD. In addition, in vitro studies suggested that JPYS may enhance tryptophan metabolism in M1 macrophage polarization and betaine metabolism in M2 macrophage polarization.

Conclusions

The JPYS formula has been shown to have beneficial impact on CKD; a key mechanism is the mitigation of inflammatory damage through the interaction between amino acid metabolism and macrophage polarization. Of specific importance in this context are the roles of tryptophan in M1 polarization and betaine in M2 polarization.

The evolving understanding of systemic mechanisms in organ-specific IgA nephropathy: a focus on gut-kidney crosstalk

The interplay between multiple organs, known as inter-organ crosstalk, represents a complex and essential research domain in understanding the mechanisms and therapies for kidney diseases. The kidneys not only interact pathologically with many other organs but also communicate with other systems through various signaling pathways. It is of paramount importance to comprehend these mechanisms for the development of more efficient therapeutic strategies. Despite extensive research in IgA nephropathy (IgAN), the most common kidney disease, the elaboration mechanism of IgAN remains challenging. Numerous studies suggest that alterations in the intestinal microbiome and its metabolites are pivotal in the progression of IgAN, opening new avenues for understanding its mechanisms. Interestingly, certain presumed probiotics, such as Akkermansia muciniphila, have been implicated in the onset of IgAN, making the exploration of gut microbiota in the context of IgAN pathogenesis even more intriguing. In this review, we summarize the status of gut microbiology studies of IgAN and explore the possible mechanisms and intervention prospects. Future research and treatment directions may increasingly emphasize systemic, multi-organ combined interventions to decelerate the advancement of kidney disease and enhance the overall prognosis of patients.

Gut microbiota regulates oxidative stress and inflammation: a double-edged sword in renal fibrosis

Gut microbiota is a complex and dynamic system that plays critical roles in human health and various disease. Progressive chronic kidney disease (CKD) suggests that patients irreversibly progress to end-stage kidney disease and need renal replacement treatments, including dialysis and transplantation. Ample evidence indicates that local oxidative stress and inflammation play pivotal roles in the pathogenesis and progression of CKD and dysbiosis of gut microbiota. CKD is always accompanied by intestinal inflammation and oxidative stress, which lead to rapid systemic translocation of bacterial-derived uraemic toxins, including indoxyl sulphate, phenyl sulphate and indole-3-acetic acid, and the consequent development and aggravation of renal fibrosis. Although inflammation and oxidative stress have been extensively discussed, there is a paucity of reports on the effects of gut microbiota on renal fibrosis and gut microbiota mediation of oxidative stress and inflammation. This review provides an overview of gut microbiota on inflammation and oxidative stress in renal fibrosis, briefly discusses regulation of the gut flora using microecological preparations and natural products, such as resveratrol, curcumin and emodin as treatments for CKD, and provides a clear pathophysiological rationale for the design of promising therapeutic strategies.