The Characteristics of Intestinal-Barrier Damage in Rats With IgA Nephropathy

Shen-yan-yi-hao oral solution ameliorates IgA nephropathy via intestinal IL-17/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis in the world, it is one of the most common causes of kidney disease and can lead to end-stage kidney disease, however, its pathogenesis is still complicated. The Shen-yan-yi-hao oral solution (SOLI) is an effective prescription for the clinical treatment of IgAN while its specific mechanism remains to be further elucidated.

AIM OF THE STUDY

This study investigates SOLI's effects on IgAN in rats, particularly on the intestinal mucosal barrier, and identifies potential therapeutic targets through network pharmacology and molecular docking, validated experimentally.

MATERIALS AND METHODS

Target genes for SOLI in IgAN were identified and analysed through molecular docking and KEGG pathway enrichment. An IgAN rat model examined SOLI's effect on renal biomarkers and cytokines involved in specific pathways, ileum mucosal lesions, and the intestinal immune system. The IL-17 pathway's role was studied in IEC-6 cells with SOLI in vitro.

RESULT

Rats developed increased proteinuria and kidney damage marked by IgA deposition and inflammation. SOLI treatment significantly ameliorated these symptoms, reduced galactose-deficient Ig A1 (Gd-IgA1), and decreased cytokines like IL-17, TNF-α, IL-6 and IL-1β etc. SOLI also normalized intestinal tight junction protein expression, ameliorated intestinal damage, and regulated intestinal immune response (focused on IL-17/NF-κB signal pathway). SOLI moderated the abnormally activated IL-17 pathway, which damages intestinal epithelial cells, suggesting IgAN treatment potential.

CONCLUSION

SOLI reduces proteinuria and enhances intestinal mucosal function in IgAN rats, kidney protection in the IgAN rat model may initiate from modulating the intestinal IL-17/NF-κB pathway and subsequent Gd-IgA1 accumulation.

Effect of Transarterial Chemotherapy on the Structure and Function of Gut Microbiota in New Zealand White Rabbits

The gut microbiota (GM) are closely related to hepatocellular carcinoma (HCC) occurrence and development. Furthermore, patients with HCC who have received transcatheter arterial chemoembolization (TACE) treatment often experience adverse gastrointestinal reactions, which may be related to changes in the GM caused by the chemotherapeutic drugs used in TACE. Therefore, we conducted animal experiments to investigate these changes. We analyzed changes in the GM of New Zealand white rabbits treated with hepatic arterial chemotherapy by measuring the levels of serological and colonic tissue markers. Simultaneously, we evaluated the correlation between the GM and these markers to explore the mechanism by which chemotherapy affects the GM. Following transarterial chemotherapy with epirubicin, the Firmicutes abundance decreased, whereas that of Proteobacteria increased. The relative abundance of beneficial bacteria, such as Muribaculaceae, Enterococcus, Ruminococcus, and Clostridia, decreased in the experimental group compared with those in the control group. However, the relative abundance of harmful bacteria, such as Bacteroides and Escherichia (Shigella), was higher in the experimental group than in the control group. Following chemotherapy, the GM of rabbits showed a dynamic change over time, first aggravating and then subsiding. The changes were most notable on the fourth day after surgery and recovered slightly on the seventh day. The changes in the host's GM before and after arterial chemotherapy are evident. Hepatic arterial chemotherapy induces dysbiosis of the intestinal microbiota, disrupts intestinal barrier function, damages the integrity of the intestinal mucosa, increases intestinal permeability, facilitates excessive passage of harmful substances through the gut-liver axis communication between the liver and intestine, and triggers activation of inflammatory pathways such as LPS-TLR-4-pSTAT3, ultimately leading to an inflammatory response. This study provides a theoretical basis for combining TACE with targeted GM intervention to treat HCC and reduce adverse gastrointestinal reactions.

Gut microbiota and risk of endocarditis: a bidirectional Mendelian randomization study

Background

The associations between gut microbiota and cardiovascular disease have been reported in previous studies. However, the relationship between gut microbiota and endocarditis remains unclear.

Methods

A bidirectional Mendelian randomization (MR) study was performed to detect the association between gut microbiota and endocarditis. Inverse variance weighted (IVW) method was considered the main result. Simultaneously, heterogeneity and pleiotropy tests were conducted.

Results

Our study suggests that family Victivallaceae (p = 0.020), genus Eubacterium fissicatena group (p = 0.047), genus Escherichia Shigella (p = 0.024), genus Peptococcus (p = 0.028) and genus Sellimonas (p = 0.005) play protective roles in endocarditis. Two microbial taxa, including genus Blautia (p = 0.006) and genus Ruminococcus2 (p = 0.024) increase the risk of endocarditis. At the same time, endocarditis has a negative effect on genus Eubacterium fissicatena group (p = 0.048). Besides, no heterogeneity or pleiotropy was found in this study.

Conclusion

Our study emphasized the certain role of specific gut microbiota in patients with endocarditis and clarified the negative effect of endocarditis on gut microbiota.

Protective effect and mechanism insight of purified Antarctic kill phospholipids against mice ulcerative colitis combined with bioinformatics

Antarctic krill oil is functional oil and has a complex phospholipids composition that poses difficulties in elucidating its effect mechanism on ulcerative colitis (UC). The mechanism of UC action was studied by bioinformatics, and the therapeutic effect of Antarctic krill phospholipids (APL) on dextran sulfate sodium (DSS)-induced colitis mice was verified. GO functional enrichment analysis uncovered an enrichment of these genes in the regulation of cell-cell adhesion, membrane region, signaling receptor activator activity, and cytokine activity. Meanwhile, the KEGG results revealed the genes were enriched in the TNF signaling pathway, pathogenic Escherichia coli infection, inflammatory bowel disease and tight junction. Animal experiments showed that APL treatment alleviated the UC symptoms and reduced inflammatory damage. Meanwhile, the expressions of the tight junction (TJ) proteins, ZO-1 and occludin, were restored, and the levels of IL-6 and TNF-α were reduced. Moreover, Firmicutes/Bacteroidetes ratio in the intestinal microbiota was regulated, and the contents of short-chain fatty acids metabolites were raised. These findings would provide an insight for the beneficial effects of APL and dietary therapy strategies for UC.

Electro-acupuncture treatment ameliorates intestinal inflammatory injury in cerebral ischemia-reperfusion rats via regulating the balance of Treg / γδ T cells

Electro-acupuncture (EA) has an anti-inflammatory role in ischemic stroke, but whether the protective effect of EA involves the regulation of the intestine barrier and Treg/ γδ T cells is unclear. Cerebral ischemia-reperfusion (I/R) injury was induced by middle cerebral artery occlusion(MCAO) for 2 h followed by reperfusion for 24 h. The rats have treated with EA at the "Baihui" acupoint(GV20). Triphenyl tetrazolium chloride (TTC) staining and Longa neurologic score were performed to evaluate the outcomes after ischemic stroke. Inflammatory factor expression levels in the serum, ischemic hemisphere brain, and small intestine were detected by ELISA or RT-qPCR. Additionally, the morphology change of the small intestine was evaluated by analyzing villus height and smooth muscle thickness. Meanwhile, the expression of tight-junction proteins, including Zonula Occludens-1 (ZO-1), Occludin, and Claudin-1, were detected to evaluate the impact of EA on mucosal permeability in the small intestine. The percentages of regulatory T cells (Tregs) (CD45⁺CD4⁺Foxp3⁺) and γδ T cells (CD45⁺CD4^-γδ T⁺) were measured to assess the effect of EA on intestinal T cells. EA decreased the brain infarction volume and intestine barrier injury in ischemic stroke rats. At the same time, it effectively suppressed the post-stroke inflammation in the brain and small intestine. More importantly, EA treatment increased the percentage of Tregs in the small intestine while reducing the rate of γδ T cells, and ultimately increased the ratio of Treg/ γδ T cells. These results demonstrated that EA ameliorated intestinal inflammation damage by regulating the Treg/ γδ T cell polarity shift and improving the intestine barrier integrity in rats with I/R injury. This may be one of the mechanisms underlying the anti-ischemic injury effects of acupuncture on stroke.

Gut microbiota changes and biological mechanism in hepatocellular carcinoma after transarterial chemoembolization treatment

Background and aims

Intestinal flora is closely associated with the occurrence and development of hepatocellular carcinoma (HCC). However, gut microbial changes and biological mechanisms in HCC after transarterial chemoembolization (TACE) treatment are rarely reported.

Methods

We evaluated changes in intestinal flora after TACE in rabbit HCC models and assessed the impact of these changes on the disease. Twenty-four rabbit VX2 HCC models were established and intestinal flora structures, intestinal barrier function, changes in blood lipopolysaccharide (LPS) levels, Toll-like receptor 4 (TLR4), Cyclooxygenase-2 (COX-2), and p-signal transducer and activator of transcription 3(p-STAT3) protein expression levels were studied after TACE treatment.

Results

Compared with healthy rabbits, the intestinal flora in HCC models exhibited structural changes; intestinal barrier function was decreased, and increased LPS levels entered the circulation. A short-term follow-up after TACE showed the procedure partially reversed the intestinal microflora disorder caused by the tumor: intestinal barrier and liver functions were improved, intestinal LPS levels in the blood were reduced, and liver metabolism toward LPS was enhanced. Correlation analyses of the first 75 significantly changed bacteria with clinical factors showed that harmful bacteria had decreased and beneficial bacteria increased. Blood LPS levels and downstream signaling molecule TLR4, COX-2, and p-STAT3 protein expression levels were reduced, which correlated with tumor drug resistance and invasion capabilities.

Conclusions

We first characterized gut microbiota changes and biological mechanisms in HCC after TACE treatment. Our data provide a theoretical research basis for TACE combined with an intestinal flora intervention and systemic chemotherapy.

The Diagnostic and Predictive Significance of Immune-Related Genes and Immune Characteristics in the Occurrence and Progression of IgA Nephropathy

Objective

To investigate the potential diagnostic and predictive significance of immune-related genes in IgA nephropathy (IgAN) and discover the abnormal glomerular inflammation in IgAN.

Methods

GSE116626 was used as a training set to identify different immune-related genes (DIRGs) and establish machine learning models for the diagnosis of IgAN; then, a nomogram model was generated based on GSE116626, and GSE115857 was used as a test set to evaluate its clinical value. Short Time-Series Expression Miner (STEM) analysis was also performed to explore the changing trend of DIRGs with the progression of IgAN lesions. GSE141344 was used with DIRGs to establish the ceRNA network associated with IgAN progression. Finally, ssGSEA analysis was performed on the GSE141295 dataset to discover the abnormal inflammation in IgAN.

Results

Machine learning (ML) performed excellently in diagnosing IgAN using six DIRGs. A nomogram model was constructed to predict IgAN based on the six DIRGs. Three trends related to IgAN lesions were identified using STEM analysis. A ceRNA network associated with IgAN progression which contained 8 miRNAs, 14 lncRNAs, and 3 mRNAs was established. A higher macrophage ratio and lower CD4+ T cell ratio in IgAN compared to controls were observed, and the correlation between macrophages and monocytes in the glomeruli of IgAN patients was inverse compared to controls.

Conclusion

This study reveals the diagnostic and predictive significance of DIRGs in IgAN and finds that the imbalance between macrophages and CD4+ immune cells may be an important pathomechanism of IgAN. These results provide potential directions for the treatment and prevention of IgAN.

Influence of Dietary Lipid Type on the Bioavailability of DDT and Its Metabolites in Soil: Mechanisms and Health Implications

The impact of dietary lipid type on DDTr (DDT and its metabolites) relative bioavailability (RBA) in soil was investigated using an in vivo mouse model and in vitro assays. Three different lipids were long chain triglycerides (LCT), medium chain triglycerides (MCT), and short chain triglycerides (SCT). DDTr-RBA markedly (p < 0.05) increased from 51.3 ± 10.8% (control) to 94.6 ± 15.9% (10% w/w LCT) and 112 ± 20.8% (20% LCT) in LCT amended treatments. A significant increase in DDTr-RBA (92.2 ± 9.84%, p < 0.05) was also observed when mice were administered diets containing 20% MCT; however, no influence on DDTr-RBA was observed for SCT amended diets. Mechanism exploration showed that LCT and MCT enhanced DDTr solubilization by a factor of 7.31-9.59 compared to controls as a consequence of micelle formation which promoted DDTr mobilization from soil. LCT significantly enhanced DDTr intestinal absorption via increasing synthesis and secretion of apolipoprotein B 48 (32.2 ± 2.08 mg/L), compared to MCT (22.1 ± 1.32 mg/L) and SCT (15.5 ± 2.03 mg/L) treated Caco-2 cells. Mouse gut microflora analysis highlighted that LCT and MCT may increase intestinal permeability by regulating abundance of Lactobacillus, which may influence the absorption of DDTr.

Metabolic Dysfunctions of Intestinal Fatty Acids and Tryptophan Reveal Immuno-Inflammatory Response Activation in IgA Nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most common form of primary glomerulonephritis. Although an important link between intestinal metabolites and immune activity is widely established, the metabolic profile of IgAN is still poorly understood, which severely limits the mechanistic studies and therapy of IgAN.

METHODS

The diversity of intestinal flora and relative abundance of metabolites in IgAN patients and healthy subjects were measured by 16s ribosomal RNA gene sequencing combined with liquid chromatography tandem-mass spectrometry. The levels of serum Gd-IgA1, IL-6, IL-10, IL-22, and TNF-a were tested by ELISA. We employed the tryptophan-targeted UHPLC-MRM-MS approach to assess the content of tryptophan metabolites quantitatively.

RESULTS

Intestinal fatty acid levels, mainly unsaturated fatty acids, were observed to be dramatically decreased in IgAN patients. Disorders in linoleic acid and arachidonic acid metabolism, metabolic imbalances of anti-/pro- inflammatory fatty acid metabolites, and intestinal AhR signaling deficiency might reflect the damage of the intestinal mucosal barrier in IgAN patients. In addition, we found that high levels of Gd-IgA1, IL-22, and TNF-α were associated with the activity of the tryptophan-kynurenine metabolic pathway, as well as lower levels of 3-indolepropionic acid. 3-indolepropionic acid, kynurenine, and indoleacrylic acid had synergistic effects on regulating immuno-inflammatory responses in IgAN patients.

CONCLUSIONS

The metabolic characteristic of fatty acids and tryptophan in the intestinal system is disturbed in IgAN patients, leading to active immune-inflammatory reactions.

Immunological drivers of IgA nephropathy: Exploring the mucosa-kidney link

IgA nephropathy (IgAN) is the most common pattern of primary glomerular disease reported worldwide. Up to 40% of those with IgAN progress to end-stage kidney disease within 20 years of diagnosis, with no currently available disease-specific treatment. This is likely to change rapidly, with evolving insights into the mechanisms driving this disease. IgAN is an immune-complex-mediated disease, and its pathophysiology has been framed by the 'four-hit hypothesis', which necessitates four events to occur for clinically significant disease to develop. However, this hypothesis does not explain the wide variability observed in its presentation or clinical progression. Recently, there has been great interest in exploring the role of the mucosal immune system in IgAN, especially given the well-established link between mucosal infections and disease flares. Knowledge of antigen-mucosal interactions is now being successfully leveraged for therapeutic purposes; the gut-directed drug Nefecon (targeted release formulation-budesonide) is on track to become the first medication to be approved specifically for the treatment of IgAN. In this review, we examine established immunological paradigms in IgAN, explore how antigen-mucosal immune responses drive disease, and discuss how this knowledge is being used to develop new treatments.

Role of gut-kidney axis in renal diseases and IgA nephropathy

PURPOSE OF REVIEW

Growing evidence show the importance of gut/kidney axis in renal diseases. Advances in gut microbiome sequencing, associated metabolites, detection of gut permeability and inflammation provide new therapeutic strategies targeting gut for kidney diseases and particularly for Immunoglobulin A (IgA) nephropathy (IgAN).

RECENT FINDINGS

The diversity and composition of gut flora have been recently deeply explored in kidney diseases. Modulation and depletion of microbiota in animal models allowed the understanding of molecular mechanisms involved in the crosstalk between gut, immune system and kidney. New clinical trials in order to positively modulate microbiota result in improvement of gastrointestinal disorders and inflammation in patients suffering with kidney diseases.

SUMMARY

The investigation of gut alterations in kidney diseases open new therapeutic strategies. In IgAN, targeted treatments for intestinal inflammation and modifications of gut microbiota seem promising.

Preventive Effects of Lactobacillus Mixture against Chronic Kidney Disease Progression through Enhancement of Beneficial Bacteria and Downregulation of Gut-Derived Uremic Toxins

Gut dysbiosis is a major contributor to adverse chronic kidney disease (CKD) progression, and microbiota-based strategies could be considered as a novel therapeutic and preventative target. In this study, a probiotic screening platform based on gut-derived uremic toxin-reducing probiotics was developed and the underlying mechanism was further verified through a 0.2% adenine-induced CKD mouse model. Two strains (Lactobacillus paracasei and Lactobacillus plantarum) were selected due to their high clearance ability and named Lactobacillus mix (Lm). The results showed that Lm significantly improved the kidney function by reducing kidney injury and fibrotic-related proteins. Furthermore, Lm decreased oxidative stress and proinflammatory reactions and elevated immune responses in the kidney. Importantly, Lm reversed gut dysbiosis and restored the abundance of commensal bacteria, especially short-chain fatty acid producers, leading to improved intestinal barrier integrity via modulation of microbial composition and metabolite production. Taken together, these findings provided evidence that Lm could be a preventive approach against CKD.

Rifaximin as a Potential Treatment for IgA Nephropathy in a Humanized Mice Model

IgA Nephropathy (IgAN) is the most common glomerulonephritis worldwide, characterized by the mesangial deposition of abnormally glycosylated IgA1 (Gd-IgA). The production of Gd-IgA occurs in mucose-associated lymphoid tissue (MALT). The microbiota plays a role in MALT modulation. Rifaximin (NORMIX^®), a non-absorbable oral antibiotic, induces positive modulation of the gut microbiota, favoring the growth of bacteria beneficial to the host. Here, we evaluate the effect of rifaximin on a humanized mice model of IgAN (α1^KI-CD89^Tg). Methods: The α1^KI-CD89^Tg mice were treated by the vehicle (olive oil) or rifaximin (NORMIX^®). Serum levels of hIgA, hIgA1-sCD89, and mIgG-hIgA1 immune complexes were determined. Glomerular hIgA1 deposit and CD11b+ cells recruitment were revealed using confocal microscopy. Furthermore, the mRNA of the B-Cell Activating Factor (BAFF), polymeric immunoglobulin receptor (pIgR), and Tumor Necrosing Factor-α (TNF-α) in gut samples were detected by qPCR. Results: Rifaximin treatment decreased the urinary protein-to-creatinine ratio, serum levels of hIgA1-sCD89 and mIgG-hIgA1 complexes, hIgA1 glomerular deposition, and CD11b+ cell infiltration. Moreover, rifaximin treatment decreased significantly BAFF, pIgR, and TNF-α mRNA expression. Conclusions: Rifaximin decreased the IgAN symptoms observed in α1^KI-CD89^Tg mice, suggesting a possible role for it in the treatment of the disease.

Advances in the role and mechanism of zonulin pathway in kidney diseases

The intestinal barrier is the first line of defense against foreign antigens. Tight junctions play an important role in maintaining the function of the intestinal wall. Zonulin is the only physiological protein discovered in recent years that can reversibly regulate tight junctions in human body. It changes the permeability of intestinal epithelial cells by regulating the state of tight junctions. Increased intestinal permeability can lead to abnormal activation of intestinal mucosal immune and bacterial translocation, then inducing systemic inflammation. It has already been reported that zonulin plays an important pathogenic role in a variety of diseases by regulating tight junctions leading to an abnormal increase of intestinal permeability. However, the research on the pathogenic role and mechanism of zonulin pathway in kidney disease is still in its infancy. Therefore, we reviewed the progress on pathophysiological characteristics of zonulin as well as the pathogenesis of zonulin in kidney disease in this paper.

Huangkui Capsule in Combination with Leflunomide Improves Immunoglobulin A Nephropathy by Inhibiting the TGF-β1/Smad3 Signaling Pathway

OBJECTIVES

To investigate the efficacy and potential molecular mechanism of Huangkui capsule in combination with leflunomide (HKL) for the treatment of immunoglobulin A nephropathy (IgAN).

METHODS

IgAN rat models were constructed by treating rats with bovine serum albumin, lipopolysaccharide, and tetrachloromethane. Th22 cells were isolated from the blood samples of patients with IgAN using a CD4+ T cell isolation kit. The expression levels of the components of the TGF-β1/Smad3 signaling pathway, namely, TGF-β1, Smad2, Smad3, Smad4, and Smad7, were detected using quantitative reverse transcription polymerase chain reaction. Cell proliferation was determined using the MTT assay, cell viability was determined using the WST 1 method, and the chemotaxis of Th22 cells was observed using the wound healing assay. Changes in the histology of the kidney tissues were analyzed using hematoxylin and eosin staining.

RESULTS

Compared with IgAN rats, the rats subjected to HKL treatment showed good improvement in kidney injuries, and the combined drug treatment performed much better than the single-drug treatment. In addition, following HKL treatment, the viability, proliferation, and chemotaxis of Th22 cells dramatically decreased (*p<0.05, **p<0.01, and ***p<0.001). In addition, CCL20, CCL22, and CCL27 levels decreased and the expression of the key components of the TGF-β1/Smad3 signaling pathway was downregulated in IgAN rats and Th22 cells (*p<0.05, ***p<0.001).

CONCLUSIONS

By targeting the TGF-β1/Smad3 signaling pathway, HKL treatment can improve kidney injury in IgAN rats as well as the excessive proliferation and metastasis of Th22 cells.