Uremia-Induced Gut Barrier Defect in 5/6 Nephrectomized Mice Is Worsened by Candida Administration through a Synergy of Uremic Toxin, Lipopolysaccharide, and (1➔3)-β-D-Glucan, but Is Attenuated by Lacticaseibacillus rhamnosus L34

Kangxianling formula attenuates renal fibrosis by regulating gut microbiota

BACKGROUND

Renal fibrosis (RF) produced adverse effect on kidney function. Recently, intestinal dysbiosis is a key regulator that promotes the formation of renal fibrosis. This study will focus on exploring the protective mechanism of Kangxianling Formula (KXL) on renal fibrosis from the perspective of intestinal flora.

METHODS

Unilateral Ureteral Obstruction (UUO) was used to construct rats' model with RF, and receive KXL formula intervention for 1 week. The renal function indicators were measured. Hematoxylin-eosin (HE), Masson and Sirus red staining were employed to detect the pathological changes of renal tissue in each group. The expression of α-SMA, Col-III, TGF-β, FN, ZO-1, and Occuludin was detected by immunofluorescence and immunohistochemistry. Rat feces samples were collected and analyzed for species' diversity using high-throughput sequencing 16S rRNA.

RESULTS

Rats in UUO groups displayed poor renal function as well as severe RF. The pro-fibrotic protein expression in renal tissues including α-SMA, Col-III, TGF-β and FN was increased in UUO rats, while ZO-1 and Occuludin -1 expression was downregulated in colon tissues. The above changes were attenuated by KXL treatment. 16S rRNA sequencing results revealed that compared with the sham group, the increased abundance of pathogenic bacteria including Acinetobacter, Enterobacter and Proteobacteria and the decreased abundance of beneficial bacteria including Actinobacteriota, Bifidobacteriales, Prevotellaceae, and Lactobacillus were found in UUO group. After the administration of KXL, the growth of potential pathogenic bacteria was reduced and the abundance of beneficial bacteria was enhanced.

CONCLUSION

KXL displays a therapeutical potential in protecting renal function and inhibiting RF, and its mechanism of action may be associated with regulating intestinal microbiota.

Causal relationship between gut microbiota and kidney diseases: a two-sample Mendelian randomization study

Background

The interplay between gut microbiome genera and inflammatory kidney-related diseases, such as nephrotic syndrome, glomerulonephritis, tubulo-interstitial nephritis, and chronic kidney disease, has been observed. However, the causal relationships between specific bacterial genera and these renal diseases have not been fully elucidated.

Objective

To investigate the potential causal links between different genera of the gut microbiome and the susceptibility to various renal conditions utilizing two-sample Mendelian randomization (MR) analyses.

Materials and methods

Genome-wide association study (GWAS) summary statistics of gut microbiota and inflammatory kidney-related diseases were obtained from published GWASs. Two-sample MR analyses were conducted using methods including inverse-variance weighted (IVW), MR Egger, and others to identify potential causal links between gut microbial genera and renal conditions. Sensitivity analyses, including Cochran's Q test and the MR-PRESSO global test, were performed to validate the robustness of the results and detect horizontal pleiotropy. In addition, a reverse MR analysis was conducted to assess reverse causation possibilities.

Results

By synthesizing insights from both primary and sensitivity analyses, this study unveiled critical associations of 12 bacterial genera with nephrotic syndrome, 7 bacterial genera with membranous nephropathy, 3 bacterial genera with glomerulonephritis, 4 bacterial genera with acute tubulo-interstitial nephritis, 6 bacterial genera with chronic tubulo-interstitial nephritis, and 7 bacterial genera with chronic kidney disease. Various genera were pinpointed as having either positive or negative causal relationships with these renal conditions, as evidenced by specific ranges of IVW-OR values (all P< 0.05). The congruence of the sensitivity analyses bolstered the primary findings, displaying no marked heterogeneity or horizontal pleiotropy. Notably, the reverse MR analysis with nephritis as the exposure did not reveal any causal relationships, thereby strengthening the resilience and validity of the primary associations.

Conclusion

This study explored the causal associations between several gut microbial genera and the risk of several inflammatory kidney-related diseases, uncovering several associations between specific gut microbial genera and nephrotic syndrome, membranous nephropathy, glomerulonephritis, tubulo-interstitial nephritis, and chronic kidney disease. These findings enhance our understanding of the complex interplay between the gut microbiome and kidney diseases, and they will be beneficial for early diagnosis and subsequent treatment.

The arsenic-lowering effect of inulin-type prebiotics in end-stage renal disease: a randomized crossover trial

Background: Circulatory imbalance of trace elements is frequent in end-stage renal disease (ESRD), leading to a deficiency of essential elements and excess of toxic elements. The present study aimed to investigate whether inulin-type fructans (ITFs) could ameliorate the circulatory imbalance by modulating gut microbiota and regulating the absorption and elimination of trace elements. Methods: Peritoneal dialysis patients were enrolled in a randomized crossover trial, undergoing interventions with ITFs (10 g d-1) and maltodextrin (placebo) over a 9-month period (with a 3-month washout). The primary outcomes included essential elements Mn, Fe, Co, Cu, Zn, Se, Sr, and Mo and potential toxic elements V, Cr, Ni, As, Cd, Ba, Tl, Pb, Th, and U in plasma. Secondary outcomes included the gut microbiome, short chain fatty acids (SCFAs), bile acids (BAs), and daily removal of trace elements through urine, dialysate and feces. Results: Among the 44 participants initially randomized, 29 completed the prebiotic, placebo or both interventions. The daily dietary intake of macronutrients and trace elements remained consistent throughout the study. The administration of 10 g d-1 ITFs significantly reduced plasma arsenic (As) by 1.03 μg L-1 (95%CI: -1.74, -0.33) (FDR-adjusted P = 0.045) down from the baseline of 3.54 μg L-1 (IQRs: 2.61-4.40) and increased the As clearance rate by urine and dialysis (P = 0.033). Positive changes in gut microbiota were also observed, including an increase in the Firmicutes/Bacteroidetes ratio (P = 0.050), a trend towards higher fecal SCFAs (P = 0.082), and elevated excretion of primary BAs (P = 0.035). However, there were no significant changes in plasma concentrations of other trace elements or their daily removal by urine, dialysis and feces. Conclusions: The daily administration of 10 g d-1 ITFs proved to be effective in reducing the circulating retention of As but demonstrated to be ineffective for other trace elements in ESRD. These sentences are ok to include but as "The clinical trial registry number is ChiCTR-INR-17013739 (https://www.chictr.org.cn/showproj.aspx?proj=21228)".

Probiotics as potential treatments to reduce myocardial remodelling and heart failure via the gut-heart axis: State-of-the-art review

Probiotics are considered to represent important modulators of gastrointestinal health through increased colonization of beneficial bacteria thus altering the gut microflora. Although these beneficial effects of probiotics are now widely recognized, emerging evidence suggests that alterations in the gut microflora also affect numerous other organ systems including the heart through a process generally referred to as the gut-heart axis. Moreover, cardiac dysfunction such as that seen in heart failure can produce an imbalance in the gut flora, known as dysbiosis, thereby further contributing to cardiac remodelling and dysfunction. The latter occurs by the production of gut-derived pro-inflammatory and pro-remodelling factors which exacerbate cardiac pathology. One of the key contributors to gut-dependent cardiac pathology is trimethylamine N-oxide (TMAO), a choline and carnitine metabolic by-product first synthesized as trimethylamine which is then converted into TMAO by a hepatic flavin-containing monooxygenase. The production of TMAO is particularly evident with regular western diets containing high amounts of both choline and carnitine. Dietary probiotics have been shown to reduce myocardial remodelling and heart failure in animal models although the precise mechanisms for these effects are not completely understood. A large number of probiotics have been shown to possess a reduced capacity to synthesize gut-derived trimethylamine and therefore TMAO thereby suggesting that inhibition of TMAO is a factor mediating the beneficial cardiac effects of probiotics. However, other potential mechanisms may also be important contributing factors. Here, we discuss the potential benefit of probiotics as effective therapeutic tools for attenuating myocardial remodelling and heart failure.

Less Severe Polymicrobial Sepsis in Conditional mgmt-Deleted Mice Using LysM-Cre System, Impacts of DNA Methylation and MGMT Inhibitor in Sepsis

The O6-methylguanine-DNA methyltransferase (MGMT) is a DNA suicide repair enzyme that might be important during sepsis but has never been explored. Then, the proteomic analysis of lipopolysaccharide (LPS)-stimulated wild-type (WT) macrophages increased proteasome proteins and reduced oxidative phosphorylation proteins compared with control, possibly related to cell injury. With LPS stimulation, mgmt null (mgmt^flox/flox; LysM-Cre^cre/-) macrophages demonstrated less profound inflammation; supernatant cytokines (TNF-α, IL-6, and IL-10) and pro-inflammatory genes (iNOS and IL-1β), with higher DNA break (phosphohistone H2AX) and cell-free DNA, but not malondialdehyde (the oxidative stress), compared with the littermate control (mgmt^flox/flox; LysM-Cre^-/-). In parallel, mgmt null mice (MGMT loss only in the myeloid cells) demonstrated less severe sepsis in the cecal ligation and puncture (CLP) model (with antibiotics), as indicated by survival and other parameters compared with sepsis in the littermate control. The mgmt null protective effect was lost in CLP mice without antibiotics, highlighting the importance of microbial control during sepsis immune modulation. However, an MGMT inhibitor in CLP with antibiotics in WT mice attenuated serum cytokines but not mortality, requiring further studies. In conclusion, an absence of mgmt in macrophages resulted in less severe CLP sepsis, implying a possible influence of guanine DNA methylation and repair in macrophages during sepsis.

Less Severe Lipopolysaccharide-Induced Inflammation in Conditional mgmt-Deleted Mice with LysM-Cre System: The Loss of DNA Repair in Macrophages

Despite the known influence of DNA methylation from lipopolysaccharide (LPS) activation, data on the O6-methylguanine-DNA methyltransferase (MGMT, a DNA suicide repair enzyme) in macrophages is still lacking. The transcriptomic profiling of epigenetic enzymes from wild-type macrophages after single and double LPS stimulation, representing acute inflammation and LPS tolerance, respectively, was performed. Small interfering RNA (siRNA) silencing of mgmt in the macrophage cell line (RAW264.7) and mgmt null (mgmt^flox/flox; LysM-Cre^cre/-) macrophages demonstrated lower secretion of TNF-α and IL-6 and lower expression of pro-inflammatory genes (iNOS and IL-1β) compared with the control. Macrophage injury after a single LPS dose and LPS tolerance was demonstrated by reduced cell viability and increased oxidative stress (dihydroethidium) compared with the activated macrophages from littermate control mice (mgmt^flox/flox; LysM-Cre^-/-). Additionally, a single LPS dose and LPS tolerance also caused mitochondrial toxicity, as indicated by reduced maximal respiratory capacity (extracellular flux analysis) in the macrophages of both mgmt null and control mice. However, LPS upregulated mgmt only in LPS-tolerant macrophages but not after the single LPS stimulation. In mice, the mgmt null group demonstrated lower serum TNF-α, IL-6, and IL-10 than control mice after either single or double LPS stimulation. Suppressed cytokine production resulting from an absence of mgmt in macrophages caused less severe LPS-induced inflammation but might worsen LPS tolerance.

Possible Effects of Uremic Toxins p-Cresol, Indoxyl Sulfate, p-Cresyl Sulfate on the Development and Progression of Colon Cancer in Patients with Chronic Renal Failure

Chronic kidney disease (CKD) induces several systemic effects, including the accumulation and production of uremic toxins responsible for the activation of various harmful processes. Gut dysbiosis has been widely described in CKD patients, even in the early stages of the disease. The abundant discharge of urea and other waste substances into the gut favors the selection of an altered intestinal microbiota in CKD patients. The prevalence of bacteria with fermentative activity leads to the release and accumulation in the gut and in the blood of several substances, such as p-Cresol (p-C), Indoxyl Sulfate (IS) and p-Cresyl Sulfate (p-CS). Since these metabolites are normally eliminated in the urine, they tend to accumulate in the blood of CKD patients proportionally to renal impairment. P-CS, IS and p-C play a fundamental role in the activation of various pro-tumorigenic processes, such as chronic systemic inflammation, the increase in the production of free radicals and immune dysfunction. An up to two-fold increase in the incidence of colon cancer development in CKD has been reported in several studies, although the pathogenic mechanisms explaining this compelling association have not yet been described. Based on our literature review, it appears likely the hypothesis of a role of p-C, IS and p-CS in colon cancer development and progression in CKD patients.

Gastrointestinal manifestations of long-term effects after COVID-19 infection in patients with dialysis or kidney transplantation: An observational cohort study

BACKGROUND

Prolonged symptoms after corona virus disease 2019 (Long-COVID) in dialysis-dependent patients and kidney transplant (KT) recipients are important as a possible risk factor for organ dysfunctions, especially gastrointestinal (GI) problems, during immunosuppressive therapy.

AIM

To identify the characteristics of GI manifestations of Long-COVID in patients with dialysis-dependent or KT status.

METHODS

This observational, prospective study included patients with COVID-19 infection, confirmed by reverse transcription polymerase chain reaction, with the onset of symptoms between 1 January 2022 and 31 July 2022 which was explored at 3 mo after the onset, either through the out-patient follow-up or by telephone interviews.

RESULTS

The 645 eligible participants consisted of 588 cases with hemodialysis (HD), 38 patients with peritoneal dialysis (PD), and 19 KT recipients who were hospitalized with COVID-19 infection during the observation. Of these, 577 (89.5%) cases agreed to the interviews, while 64 (10.9%) patients with HD and 4 (10.5%) cases of PD were excluded. The mean age was 52 ± 11 years with 52% women. The median dialysis duration was 7 ± 3 and 5 ± 1 years for HD and PD groups, respectively, and the median time post-transplantation was 6 ± 2 years. Long-COVID was identified in 293/524 (56%) and 21/34 (62%) in HD and PD, respectively, and 7/19 (37%) KT recipients. Fatigue was the most prevalent (96%) of the non-GI tract symptoms, whereas anorexia (90.9%), loss of taste (64.4%), and abdominal pain (62.5%) were the first three common GI manifestations of Long-COVID. Notably, there were 6 cases of mesenteric panniculitis from 19 patients with GI symptoms in the KT group.

CONCLUSION

Different from patients with non-chronic kidney disease, there was a high prevalence of GI manifestations of Long-COVID in dialysis-dependent patients and KT recipients. An appropriate long-term follow-up in these vulnerable populations after COVID-19 infection is possibly necessary.

Less Severe Sepsis in Cecal Ligation and Puncture Models with and without Lipopolysaccharide in Mice with Conditional Ezh2-Deleted Macrophages (LysM-Cre System)

Despite a previous report on less inflammatory responses in mice with an absence of the enhancer of zeste homologue 2 (Ezh2), a histone lysine methyltransferase of epigenetic regulation, using a lipopolysaccharide (LPS) injection model, proteomic analysis and cecal ligation and puncture (CLP), a sepsis model that more resembles human conditions was devised. As such, analysis of cellular and secreted protein (proteome and secretome) after a single LPS activation and LPS tolerance in macrophages from Ezh2 null (Ezh2^flox/flox; LysM-Cre^cre/-) mice (Ezh2 null) and the littermate control mice (Ezh2^fl/fl; LysM-Cre^-/-) (Ezh2 control) compared with the unstimulated cells from each group indicated fewer activities in Ezh2 null macrophages, especially by the volcano plot analysis. Indeed, supernatant IL-1β and expression of genes in pro-inflammatory M1 macrophage polarization (IL-1β and iNOS), TNF-α, and NF-κB (a transcription factor) were lower in Ezh2 null macrophages compared with the control. In LPS tolerance, downregulated NF-κB compared with the control was also demonstrated in Ezh2 null cells. In CLP sepsis mice, those with CLP alone and CLP at 2 days after twice receiving LPS injection, representing sepsis and sepsis after endotoxemia, respectively, symptoms were less severe in Ezh2 null mice, as indicated by survival analysis and other biomarkers. However, the Ezh2 inhibitor improved survival only in CLP, but not LPS with CLP. In conclusion, an absence of Ezh2 in macrophages resulted in less severe sepsis, and the use of an Ezh2 inhibitor might be beneficial in sepsis.

Cyclic GMP-AMP Synthase (cGAS) Deletion Reduces Severity in Bilateral Nephrectomy Mice through Changes in Neutrophil Extracellular Traps and Mitochondrial Respiration

Uremia-induced systemic inflammation is partly caused by the dissemination of microbial molecules such as lipopolysaccharide and bacterial double-stranded DNA from leaked gut damaged by immune cells in response to the microbial molecules. Cyclic GMP-AMP synthase (cGAS) can recognize fragmented DNA and induce cGAMP synthesis for the activation of the stimulator of interferon genes (STING) pathway. To study the effect of cGAS in uremia-induced systemic inflammation, we performed bilateral nephrectomy (BNx) in wild-type and cGAS knock-out mice and found that the gut leakage and blood uremia from both groups were similar. However, serum cytokines (TNF-α and IL-6) and neutrophil extracellular traps (NETs) decreased significantly in cGAS^-/- neutrophils after stimulation with LPS or bacterial cell-free DNA. Transcriptomic analysis of LPS-stimulated cGAS^-/- neutrophils also confirmed the down-regulation of neutrophil effector functions. The extracellular flux analysis showed that cGAS^-/- neutrophils exhibited a higher respiratory rate than wild-type neutrophils despite having similar mitochondrial abundance and function. Our results suggest that cGAS may control effector functions and the mitochondrial respiration of neutrophils in response to LPS or bacterial DNA.

The Regulatory Roles of Ezh2 in Response to Lipopolysaccharide (LPS) in Macrophages and Mice with Conditional Ezh2 Deletion with LysM-Cre System

The responses of macrophages to lipopolysaccharide (LPS) might determine the direction of clinical manifestations of sepsis, which is the immune response against severe infection. Meanwhile, the enhancer of zeste homologue 2 (Ezh2), a histone lysine methyltransferase of epigenetic regulation, might interfere with LPS response. Transcriptomic analysis on LPS-activated wild-type macrophages demonstrated an alteration of several epigenetic enzymes. Although the Ezh2-silencing macrophages (RAW264.7), using small interfering RNA (siRNA), indicated a non-different response to the control cells after a single LPS stimulation, the Ezh2-reducing cells demonstrated a less severe LPS tolerance, after two LPS stimulations, as determined by the higher supernatant TNF-α. With a single LPS stimulation, Ezh2 null (Ezh2flox/flox; LysM-Crecre/−) macrophages demonstrated lower supernatant TNF-α than Ezh2 control (Ezh2fl/fl; LysM-Cre−/−), perhaps due to an upregulation of Socs3, which is a suppressor of cytokine signaling 3, due to the loss of the Ezh2 gene. In LPS tolerance, Ezh2 null macrophages indicated higher supernatant TNF-α and IL-6 than the control, supporting an impact of the loss of the Ezh2 inhibitory gene. In parallel, Ezh2 null mice demonstrated lower serum TNF-α and IL-6 than the control mice after an LPS injection, indicating a less severe LPS-induced hyper-inflammation in Ezh2 null mice. On the other hand, there were similar serum cytokines after LPS tolerance and the non-reduction of serum cytokines after the second dose of LPS, indicating less severe LPS tolerance in Ezh2 null mice compared with control mice. In conclusion, an absence of Ezh2 in macrophages resulted in less severe LPS-induced inflammation, as indicated by low serum cytokines, with less severe LPS tolerance, as demonstrated by higher cytokine production, partly through the upregulated Socs3.

Lacticaseibacilli attenuated fecal dysbiosis and metabolome changes in Candida-administered bilateral nephrectomy mice

The impacts of metabolomic changes (reduced short-chain-fatty acids; SCFAs) in uremic condition is not fully understood. Once daily Candida gavage with or without probiotics (different times of administration) for 1 week prior to bilateral nephrectomy (Bil Nep) in 8-week-old C57BL6 mice as the possible models more resemble human conditions were performed. Candida-administered Bil Nep mice demonstrated more severe conditions than Bil Nep alone as indicated by mortality (n = 10/group) and other 48 h parameters (n = 6-8/group), including serum cytokines, leaky gut (FITC-dextran assay, endotoxemia, serum beta-glucan, and loss of Zona-occludens-1), and dysbiosis (increased Enterobacteriaceae with decreased diversity in microbiome analysis) (n = 3/group for fecal microbiome) without the difference in uremia (serum creatinine). With nuclear magnetic resonance metabolome analysis (n = 3-5/group), Bil Nep reduced fecal butyric (and propionic) acid and blood 3-hydroxy butyrate compared with sham and Candida-Bil Nep altered metabolomic patterns compared with Bil Nep alone. Then, Lacticaseibacillus rhamnosus dfa1 (SCFA-producing Lacticaseibacilli) (n = 8/group) attenuated the model severity (mortality, leaky gut, serum cytokines, and increased fecal butyrate) of Bil Nep mice (n = 6/group) (regardless of Candida). In enterocytes (Caco-2 cells), butyrate attenuated injury induced by indoxyl sulfate (a gut-derived uremic toxin) as indicated by transepithelial electrical resistance, supernatant IL-8, NFκB expression, and cell energy status (mitochondria and glycolysis activities by extracellular flux analysis). In conclusion, the reduced butyrate by uremia was not enhanced by Candida administration; however, the presence of Candida in the gut induced a leaky gut that was attenuated by SCFA-producing probiotics. Our data support the use of probiotics in uremia.

Lacticaseibacillus rhamnosus dfa1 Attenuate Cecal Ligation-Induced Systemic Inflammation through the Interference in Gut Dysbiosis, Leaky Gut, and Enterocytic Cell Energy

Despite an uncommon condition, the clinical management of phlegmon appendicitis (retention of the intra-abdominal appendiceal abscess) is still controversial, and probiotics might be partly helpful. Then, the retained ligated cecal appendage (without gut obstruction) with or without oral Lacticaseibacillus rhamnosus dfa1 (started at 4 days prior to the surgery) was used as a representative model. At 5 days post-surgery, the cecal-ligated mice demonstrated weight loss, soft stool, gut barrier defect (leaky gut using FITC-dextran assay), fecal dysbiosis (increased Proteobacteria with reduced bacterial diversity), bacteremia, elevated serum cytokines, and spleen apoptosis without kidney and liver damage. Interestingly, the probiotics attenuated disease severity as indicated by stool consistency index, FITC-dextran assay, serum cytokines, spleen apoptosis, fecal microbiota analysis (reduced Proteobacteria), and mortality. Additionally, impacts of anti-inflammatory substances from culture media of the probiotics were demonstrated by attenuation of starvation injury in the Caco-2 enterocyte cell line as indicated by transepithelial electrical resistance (TEER), inflammatory markers (supernatant IL-8 with gene expression of TLR4 and NF-κB), cell energy status (extracellular flux analysis), and the reactive oxygen species (malondialdehyde). In conclusion, gut dysbiosis and leaky-gut-induced systemic inflammation might be helpful clinical parameters for patients with phlegmon appendicitis. Additionally, the leaky gut might be attenuated by some beneficial molecules from probiotics.

Lipopolysaccharide Tolerance Enhances Murine Norovirus Reactivation: An Impact of Macrophages Mainly Evaluated by Proteomic Analysis

Because of endotoxemia during sepsis (a severe life-threatening infection), lipopolysaccharide (LPS) tolerance (the reduced responses to the repeated LPS stimulation) might be one of the causes of sepsis-induced immune exhaustion (the increased susceptibility to secondary infection and/or viral reactivation). In LPS tolerance macrophage (twice-stimulated LPS, LPS/LPS) compared with a single LPS stimulation (N/LPS), there was (i) reduced energy of the cell in both glycolysis and mitochondrial activities (extracellular flux analysis), (ii) decreased abundance of the following proteins (proteomic analysis): (a) complex I and II of the mitochondrial electron transport chain, (b) most of the glycolysis enzymes, (c) anti-viral responses with Myxovirus resistance protein 1 (Mx1) and Ubiquitin-like protein ISG15 (Isg15), (d) antigen presentation pathways, and (iii) the down-regulated anti-viral genes, such as Mx1 and Isg15 (polymerase chain reaction). To test the correlation between LPS tolerance and viral reactivation, asymptomatic mice with and without murine norovirus (MNV) infection as determined in feces were tested. In MNV-positive mice, MNV abundance in the cecum, but not in feces, of LPS/LPS mice was higher than that in N/LPS and control groups, while MNV abundance of N/LPS and control were similar. Additionally, the down-regulated Mx1 and Isg15 were also demonstrated in the cecum, liver, and spleen in LPS/LPS-activated mice, regardless of MNV infection, while N/LPS more prominently upregulated these genes in the cecum of MNV-positive mice compared with the MNV-negative group. In conclusion, defects in anti-viral responses after LPS tolerance, perhaps through the reduced energy status of macrophages, might partly be responsible for the viral reactivation. More studies on patients are of interest.

Candida Administration in 5/6 Nephrectomized Mice Enhanced Fibrosis in Internal Organs: An Impact of Lipopolysaccharide and (1→3)-β-D-Glucan from Leaky Gut

Uremic toxins and gut dysbiosis in advanced chronic kidney disease (CKD) can induce gut leakage, causing the translocation of gut microbial molecules into the systemic circulation. Lipopolysaccharide (LPS) and (1→3)-β-D-glucan (BG) are the major gut microbial molecules of Gram-negative bacteria and fungi, respectively, and can induce inflammation in several organs. Here, the fibrosis in the kidney, liver, and heart was investigated in oral C. albicans-administered 5/6 nephrectomized (Candida-5/6 Nx) mice. At 20 weeks post 5/6 Nx, Candida-5/6 Nx mice demonstrated increased 24 h proteinuria, liver enzymes, and serum cytokines (TNF-α, IL-6, and IL-10), but not weight loss, systolic blood pressure, hematocrit, serum creatinine, or gut-derived uremic toxins (TMAO and indoxyl sulfate), compared to in 5/6 Nx alone. The gut leakage in Candida-5/6 Nx was more severe, as indicated by FITC-dextran assay, endotoxemia, and serum BG. The areas of fibrosis from histopathology, along with the upregulated gene expression of Toll-like receptor 4 (TLR-4) and Dectin-1, the receptors for LPS and BG, respectively, were higher in the kidney, liver, and heart. In vitro, LPS combined with BG increased the supernatant IL-6 and TNF-α, upregulated the genes of pro-inflammation and pro-fibrotic processes, Dectin-1, and TLR-4 in renal tubular (HK-2) cells and hepatocytes (HepG2), when compared with LPS or BG alone. This supported the pro-inflammation-induced fibrosis and the possible LPS-BG additive effects on kidney and liver fibrosis. In conclusion, uremia-induced leaky gut causes the translocation of gut LPS and BG into circulation, which activates the pro-inflammatory and pro-fibrotic pathways, causing internal organ fibrosis. Our results support the crosstalk among several organs in CKD through a leaky gut.

Bacteroides plebeius improves muscle wasting in chronic kidney disease by modulating the gut-renal muscle axis

Chronic kidney disease (CKD) affects approximately 10% of the global population. Muscle atrophy occurs in patients with almost all types of CKD, and the gut microbiome is closely related to protein consumption during chronic renal failure (CRF). This study investigated the effects of Bacteroides plebeius on protein energy consumption in rats with CKD, and our results suggest that Bacteroides plebeius may combat muscle atrophy through the Mystn/ActRIIB/SMAD2 pathway. A total of 5/6 Nx rats were used as a model of muscle wasting in CKD. The rats with muscle wasting were administered Bacteroides plebeius (2 × 10⁸  cfu/0.2 ml) for 8 weeks. The results showed that Bacteroides plebeius administration significantly inhibited muscle wasting in CKD. High-throughput 16 S rRNA pyrosequencing revealed that supplementation with Bacteroides plebeius rescued disturbances in the gut microbiota. Bacteroides plebeius could also enhance the barrier function of the intestinal mucosa. Bacteroides plebeius may modulate the gut microbiome and reduce protein consumption by increasing the abundance of probiotics and reducing damage to the intestinal mucosal barrier. Our findings suggest that Bacteroides plebeius may combat muscle atrophy through the Mystn/ActRIIB/SMAD2 pathway.

Beta-Glucan from S. cerevisiae Protected AOM-Induced Colon Cancer in cGAS-Deficient Mice Partly through Dectin-1-Manipulated Macrophage Cell Energy

Although the impacts of Saccharomyces cerevisiae on cancers are mentioned, data on its use in mice with cyclic GMP-AMP synthase deficiency (cGAS-/-) are even rarer. Here, 12 weeks of oral administration of S. cerevisiae protected cGAS-/- mice from azoxymethane (AOM)-induced colon cancers, partly through dysbiosis attenuation (fecal microbiome analysis). In parallel, a daily intralesional injection of a whole glucan particle (WGP; the beta-glucan extracted from S. cerevisiae) attenuated the growth of subcutaneous tumor using MC38 (murine colon cancer cell line) in cGAS-/- mice. Interestingly, the incubation of fluorescent-stained MC38 with several subtypes of macrophages, including M1 (using Lipopolysaccharide; LPS), M2 (IL-4), and tumor-associated macrophages (TAM; using MC38 supernatant activation), could not further reduce the tumor burdens (fluorescent intensity) compared with M0 (control culture media). However, WGP enhanced tumoricidal activities (fluorescent intensity), the genes of M1 pro-inflammatory macrophage polarization (IL-1β and iNOS), and Dectin-1 expression and increased cell energy status (extracellular flux analysis) in M0, M2, and TAM. In M1, WGP could not increase tumoricidal activities, Dectin-1, and glycolysis activity, despite the upregulated IL-1β. In conclusion, S. cerevisiae inhibited the growth of colon cancers through dysbiosis attenuation and macrophage energy activation, partly through Dectin-1 stimulation. Our data support the use of S. cerevisiae for colon cancer protection.

Helicobacter pylori, Protected from Antibiotics and Stresses Inside Candida albicans Vacuoles, Cause Gastritis in Mice

Due to (i) the simultaneous presence of Helicobacter pylori (ulcer-induced bacteria) and Candida albicans in the stomach and (ii) the possibility of prokaryotic–eukaryotic endosymbiosis (intravacuolar H. pylori in the yeast cells) under stresses, we tested this symbiosis in vitro and in vivo. To that end, intravacuolar H. pylori were induced by the co-incubation of C. albicans with H. pylori under several stresses (acidic pH, non-H. pylori-enrichment media, and aerobic environments); the results were detectable by direct microscopy (wet mount) and real-time polymerase chain reaction (PCR). Indeed, intravacuolar H. pylori were predominant under all stresses, especially the lower pH level (pH 2–3). Interestingly, the H. pylori (an amoxicillin-sensitive strain) inside C. albicans were protected from the antibiotic (amoxicillin), while extracellular H. pylori were neutralizable, as indicated by the culture. In parallel, the oral administration of intravacuolar H. pylori in mice caused H. pylori colonization in the stomach resulting in gastritis, as indicated by gastric histopathology and tissue cytokines, similar to the administration of free H. pylori (extra-Candida bacteria). In conclusion, Candida protected H. pylori from stresses and antibiotics, and the intravacuolar H. pylori were able to be released from the yeast cells, causing gastric inflammation with neutrophil accumulations.