Causal relationship between gut microbiota and diabetic nephropathy: A bidirectional mendelian randomization study.

In this study, we summarized the key findings and potential implications of association studies investigating the relationship between gut microbiota composition and risks for Diabetic nephropathy (DN). We used Mendelian randomization (MR) analysis to explore the relationship between gut microbiota and DN using two different publicly available DN databases. The results were also summarized using five mainstream MR analysis methods. We controlled for various possible biases in the results. The results showed that specific bacterial genera were associated with increased or decreased risk of DN. These associations can be attributed to a variety of factors, including metabolites produced by certain bacteria. Most of our findings are consistent with the existing research findings, but there are still some differences with the existing results. In addition, we also pointed out that some microbiota that may be associated with DN but remain unnoticed can bring new research directions. Our work made use of MR, a reliable technique for examining causal correlations using genetic data investigating potential processes, carrying out longitudinal studies, looking into intervention options, and using a multi-omics approach may be future research avenues. Further, our findings also point to a few unexplored possible study paths for DN in the future. These initiatives may improve our reconciliation of the internal relationships between the gut microbiota and DN and pave the way for more precise prevention and treatment methods. However, it is also critical to recognize any potential restrictions, such as those caused by sample size, population variety, and analytical techniques.

Association between the gut microbiota and diabetic nephropathy: a two-sample Mendelian randomization study.

Numerous studies have revealed a correlation between the risk of developing diabetic nephropathy (DN) and the gut microbiota (GM) composition. However, it remains uncertain whether the GM composition causes DN. We aimed to explore any potential causal links between the GM composition and the risk of developing DN. A meta-analysis conducted by the MiBioGen consortium of the largest genome-wide association study (GWAS) provided aggregated data on the GM. DN data were obtained from the IEU database. The inverse-variance weighting (IVW) method was employed as the primary analytical approach. The IVW analysis indicated that genus Dialister (OR = 0.51, 95% CI: 0.34-0.77, p = 0.00118) was protective against DN. In addition, class Gammaproteobacteria (OR = 0.47, 95% CI: 0.27-0.83, p = 0.0096), class Lentisphaeria (OR =0.76, 95% CI: 0.68-0.99, p = 0.04), order Victivallales (OR = 0.76, 95% CI: 0.58-0.99, p = 0.04), and phylum Proteobacteria (OR = 0.53, 95% CI: 0.33-0.85, p = 0.00872) were negatively associated with the risk of developing DN. Genus LachnospiraceaeUCG008 (OR =1.45, 95% CI: 1.08-1.95, p = 0.01), order Bacteroidales (OR = 1.59, 95% CI: 1.02-2.49, p = 0.04), and genus Terrisporobacter (OR = 1.98, 95% CI: 1.14-3.45, p = 0.015) were positively associated with the risk of developing DN. In this study, we established a causal relationship between the genus Dialister and the risk of developing DN. Further trials are required to confirm the protective effects of probiotics on DN and to elucidate the precise protective mechanisms involving genus Dialister and DN.

Gut microbiota, key to unlocking the door of diabetic kidney disease.

This review discusses the influence of gut microbiota dysbiosis on diabetic kidney disease through metabolite profile changes and immune and inflammatory mechanisms. We also elaborate on the mechanism of dysbiosis in the onset and development of other kidney diseases.

The change of gut microbiota-derived short-chain fatty acids in diabetic kidney disease.

BACKGROUND: Previous studies found the dysbiosis of intestinal microbiota in diabetic kidney disease (DKD), especially the decreased SCFA-producing bacteria. We aimed to investigate the concentration of the stool and serum short-chain fatty acids (SCFAs), gut microbiota-derived metabolites, in individuals with DKD and reveal the correlations between SCFAs and renal function. METHODS: A total of 30 participants with DKD, 30 participants with type 2 diabetes mellitus (DM), and 30 normal controls (NC) in HwaMei Hospital were recruited from 1/1/2018 to 12/31/2019. Participants with DKD were divided into low estimated glomerular filtration rate (eGFR)(eGFR<60ml/min, n=14) and high eGFR (eGFR≥60ml/min, n=16) subgroups. Stool and serum were measured for SCFAs with gas chromatograph-mass spectrometry. RESULTS: The DKD group showed markedly lower levels of fecal acetate, propionate, and butyrate versus NC (p<0.001, p<0.001, p=0.018, respectively) [1027.32(784.21-1357.90)]vs[2064.59(1561.82-2637.44)]µg/g,[929.53(493.65-1344.26)]vs[1684.57(1110.54-2324.69)]µg/g,[851.39(409.57-1611.65)] vs[1440.74(1004.15-2594.73)]µg/g, respectively, and the lowest fecal total SCFAs concentration among the groups. DKD group also had a lower serum caproate concentration than that with diabetes (p=0.020)[0.57(0.47-0.61)]vs[0.65(0.53-0.79)]µmol/L. In the univariate regression analysis, fecal and serum acetate correlated with eGFR (OR=1.013, p=0.072; OR=1.017, p=0.032). The correlation between serum total SCFAs and eGFR showed statistical significance (OR=1.019, p=0.024) unadjusted and a borderline significance (OR=1.024, p=0.063) when adjusted for Hb and LDL. The decrease in serum acetate and total SCFAs were found of borderline significant difference in both subgroups (p=0.055, p=0.050). CONCLUSION: This study provides evidence that in individuals with DKD, serum and fecal SCFAs levels (fecal level in particular) were lowered, and there was a negative correlation between SCFAs and renal function.

The gut microbiome in differential diagnosis of diabetic kidney disease and membranous nephropathy.

BACKGROUND: Diabetic kidney disease (DKD) and membranous nephropathy (MN) are the two major causes of end-stage renal disease (ESRD). Increasing evidence has shown that intestinal dysbiosis is associated with many diseases. The aim of this study was to explore the composition of the gut microbiome in DKD and MN patients. METHODS: 16S rRNA gene sequencing was performed on 271 fecal samples (DKD = 129 and MN = 142), and taxonomic annotation of microbial composition and function was completed. RESULTS: We observed distinct microbial communities between the two groups, with MN samples exhibiting more severe dysbiosis than DKD samples. Relative increases in genera producing short-chain fatty acids (SCFAs) in DKD and a higher proportion of potential pathogens in MN were the main contributors to the microbiome alterations in the two groups. Five-fold cross-validation was performed on a random forest model, and four operational taxonomic unit (OTU)-based microbial markers were selected to distinguish DKD from MN. The results showed 92.42% accuracy in the training set and 94.52% accuracy in the testing set, indicating high potential for these microbiome-based markers in separating MN from DKD. Overexpression of several amino acid metabolic pathways, carbohydrate metabolism and lipid metabolism was found in DKD, while interconversion of pentose/glucoronate and membrane transport in relation to ABC transporters and the phosphotransferase system were increased in MN. CONCLUSION: The composition of the gut microbiome appears to differ considerably between patients with DKD and those with MN. Thus, microbiome-based markers could be used as an alternative tool to distinguish DKD and MN.

Probiotic supplementation in diabetic hemodialysis patients has beneficial metabolic effects.

This study determined the effects of probiotic supplementation on glycemic control, lipid concentrations, biomarkers of inflammation and oxidative stress in 60 diabetic patients on hemodialysis in a parallel randomized double-blind placebo-controlled clinical trial. Participants were initially matched based on sex, duration of dialysis and diabetes, body mass index and age. Subsequently, they were randomly divided into two groups to take either a capsule containing the probiotics Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium bifidum or placebo for 12 weeks. Based on three-day dietary records throughout the trial, there was no significant change in dietary macro- and micro-nutrients or total dietary fiber to confound results. After the 12 weeks, analysis of patients who received probiotic supplements compared with the placebo showed they had significantly decreased fasting plasma glucose (-22.0 vs. +6.6 mg/dl), serum insulin (-6.4 vs. +2.3 µIU/ml), homeostasis model of assessment-estimated insulin resistance (-2.9 vs. +2.5), homeostasis model of assessment-estimated beta-cell function (-14.1 vs. +6.1) and HbA1c (-0.4 vs. -0.1%,), and improved quantitative insulin sensitivity check index (+0.03 vs. -0.02). Additionally, compared with the placebo, probiotic supplementation resulted in significant reductions in serum high-sensitivity C-reactive protein (-1933 vs. +252 ng/ml), plasma malondialdehyde (-0.3 vs. +1.0 µmol/l), subjective global assessment scores (-0.7 vs. +0.7) and total iron binding capacity (-230 vs. +33 µg/dl), and a significant increase in plasma total antioxidant capacity (+15 vs. -88 mmol/l). Thus, probiotic supplementation for 12 weeks among diabetic hemodialysis patients had beneficial effects on parameters of glucose homeostasis, and some biomarkers of inflammation and oxidative stress.

Infection-related mortality is higher for kidney allograft recipients with pretransplant diabetes mellitus.

AIMS/HYPOTHESIS: The risk of infection-related mortality in kidney allograft recipients with pre-existing diabetes mellitus is unknown. We determined the risk of infection-related mortality after kidney transplantation in a population-based cohort stratified by diagnosis of pre-existing diabetes mellitus. METHODS: We linked data between two national registries (Hospital Episode Statistics and the Office for National Statistics) to select all mortality events after kidney transplantation in England between April 2001 and March 2012. The primary outcome measure was infection-related mortality after transplantation comparing diabetic with non-diabetic recipients. RESULTS: A total of 19,103 kidney allograft recipients were analysed; 2,968 (15.5%) were known to have diabetes before kidney transplantation. After transplantation, 2,085 deaths (10.9%) occurred (median follow-up 4.4 years [interquartile range 2.2-7.3]), with 434 classified as secondary to infection (20.8% of all deaths). Risk of overall (16.0% vs 10.0%, p < 0.001) and infection-related (3.3% vs 2.1%, p < 0.001) mortality after kidney transplantation was higher for diabetic than non-diabetic recipients, respectively. No cytomegalovirus-related deaths occurred in diabetic recipients compared with 5.7% in non-diabetic recipients (p < 0.007), with a trend towards more unspecified sepsis in diabetic recipients (30.6% vs 22.6%, respectively, p = 0.070). Diabetes at the time of transplantation was an independent risk factor predicting infection-related mortality in kidney allograft recipients after transplantation (HR 1.71 [95% CI 1.36, 2.15], p < 0.001). CONCLUSIONS/INTERPRETATION: Infection-related mortality is more common in kidney allograft recipients with pre-existing diabetes mellitus. Further work is required to determine whether attenuated immunosuppression is beneficial for diabetic kidney allograft recipients.

Gut microbiota microbial metabolites in diabetic nephropathy patients: far to go.

Diabetic nephropathy (DN) is one of the main complications of diabetes and a major cause of end-stage renal disease, which has a severe impact on the quality of life of patients. Strict control of blood sugar and blood pressure, including the use of renin-angiotensin-aldosterone system inhibitors, can delay the progression of diabetic nephropathy but cannot prevent it from eventually developing into end-stage renal disease. In recent years, many studies have shown a close relationship between gut microbiota imbalance and the occurrence and development of DN. This review discusses the latest research findings on the correlation between gut microbiota and microbial metabolites in DN, including the manifestations of the gut microbiota and microbial metabolites in DN patients, the application of the gut microbiota and microbial metabolites in the diagnosis of DN, their role in disease progression, and so on, to elucidate the role of the gut microbiota and microbial metabolites in the occurrence and prevention of DN and provide a theoretical basis and methods for clinical diagnosis and treatment.

High incidence of Aggregatibacter actinomycetemcomitans infection in patients with cerebral infarction and diabetic renal failure: a cross-sectional study.

BACKGROUND: Recent epidemiological studies suggest that periodontitis is a major risk factor for renal failure and cerebral infarction. The aim of this study was to evaluate the association among periodontitis, renal failure, and cerebral infarction, focusing on microbiological and immunological features. METHODS: Twenty-one patients treated with hemodialysis (HD) were enrolled in this study. They were 8 with diabetic nephropathy and 13 with non-diabetic nephropathy. Blood examination, periodontal examination, brain magnetic resonance image (MRI), and dental radiography were performed on all patients. Subgingival plaque, saliva, and blood samples were analyzed for the periodontal pathogens, Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P. gingivalis), and Prevotella intermedia (P. intermedia) using quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). RESULTS: We found that the patients with diabetic nephropathy had more A. actinomycetemcomitans compared with non-diabetic nephropathy (P = 0.038) in dental plaque. Furthermore, the patients with diabetic nephropathy showed a significantly higher incidence of cerebral infarction compared with those with non-diabetic nephropathy (P = 0.029). Clinical oral and radiographic scores tended to be higher among patients in the diabetic nephropathy group than in the non-diabetic nephropathy group. CONCLUSIONS: Periodontal pathogens, particularly A. actinomycetemcomitans, may play a role, at least a part, in the development of cerebral infarction in Japanese HD patients with diabetic nephropathy.

Association of Helicobacter pylori infection with diabetes mellitus and diabetic nephropathy: a meta-analysis of 39 studies involving more than 20,000 participants.

BACKGROUND: Helicobacter pylori infects more than half of the world's population. The aim of this study was to quantify the association between H. pylori infection and the risk of diabetes mellitus and diabetic nephropathy, and to detect at which stage the infection might have higher pathogenicity in the disease-free status-diabetes mellitus-diabetic nephropathy process. METHODS: A literature search was performed to identify studies published between 1997 and 2012 for relative risk estimates. Fixed and random effects meta-analytical techniques were conducted for diabetes mellitus and diabetic nephropathy. RESULTS: Thirty-seven case-control studies and 2 cohort studies were included. H. pylori was associated with an increased risk of each type of diabetes mellitus (odds ratio (OR) 2.00, 95% confidence interval (CI) 1.82-2.20, p for heterogeneity = 0.07). The infection was also associated with increased risks of type 1 and type 2 diabetes mellitus, separately (OR 1.99, 95% CI 1.52-2.60, p for heterogeneity = 0.15, and OR 2.15, 95% CI 1.81-2.55, p for heterogeneity = 0.24, respectively). In addition, we found a significant association between H. pylori infection and diabetic nephropathy risk (OR 1.60, 95% CI 1.10-2.33, p for heterogeneity = 0.44). CONCLUSIONS: Our meta-analyses suggest a relationship between H. pylori infection and the risk of diabetes mellitus and diabetic nephropathy. The bacterium may be able to play its pathogenic role in the whole disease process, and this action may be stronger in type 2 diabetic patients than in type 1 diabetic patients.

The Intestinal Microbiota Composition in Early and Late Stages of Diabetic Kidney Disease.

Many studies have suggested that gut microbiota dysbiosis may be one of the pathogenesis factors of diabetes mellitus (DM), while it is not clear whether it is involved in the development of diabetic kidney diseases (DKD). The objective of this study was to determine bacterial taxa biomarkers during the progression of DKD by investigating bacterial compositional changes in early and late DKD. 16S rRNA gene sequencing was performed on fecal samples, including the diabetes mellitus (DM), DNa (early DKD), and DNb (late DKD) groups. Taxonomic annotation of microbial composition was performed. Samples were sequenced on the Illumina NovaSeq platform. At the genus level, we found counts of Fusobacterium, Parabacteroides, and Ruminococcus_gnavus were significantly elevated both in the DNa group (P = 0.0001, 0.0007, and 0.0174, respectively) and the DNb group (P < 0.0001, 0.0012, and 0.0003, respectively) compared with those in the DM group. Only the level of Agathobacter was significantly decreased in the DNa group than the DM group and in the DNb group than the DNa group. Counts of Prevotella_9, Roseburia were significantly decreased in the DNa group compared with those in the DM group (P = 0.001 and 0.006, respectively) and in the DNb group compared with those in the DM group (P < 0.0001 and 0.003, respectively). Levels of Agathobacter, Prevotella_9, Lachnospira, and Roseburia were positively correlated with an estimated glomerular filtration rate (eGFR), but negatively correlated with microalbuminuria (MAU), 24 h urinary protein quantity (24hUP), and serum creatinine (Scr). Moreover, the areas under the curve (AUCs) of Agathobacter and Fusobacteria were 83.33% and 80.77%, respectively, for the DM and DNa cohorts, respectively. Notably, the largest AUC for DNa and DNb cohorts was also that of Agathobacter at 83.60%. Gut microbiota dysbiosis was found in the early and late stages of DKD, especially in the early stage. Agathobacter may be the most promising intestinal bacteria biomarker that can help distinguish different stages of DKD. IMPORTANCE It is not clear as to whether gut microbiota dysbiosis is involved in the progression of DKD. This study may be the first to explore gut microbiota compositional changes in diabetes, early-DKD, and late DKD. We identify different gut microbial characteristics during different stages of DKD. Gut microbiota dysbiosis is found in the early and late stages of DKD. Agathobacter may be the most promising intestinal bacteria biomarker that can help distinguish different stages of DKD, although further studies are warranted to illustrate these mechanisms.

Paecilomyces cicadae-fermented Radix astragali ameliorate diabetic nephropathy in mice by modulating the gut microbiota.

The occurrence and development of diabetic nephropathy (DN) are closely related to gut microbiota. Paecilomyces cicadae is a medicinal and edible fungus. Radix astragali is a therapeutic material for unifying Chinese Qi. They can delay the occurrence and development of kidney disease. In recent years, solid-state fermentation of edible fungi and traditional Chinese medicine has become a hot issue.Hypothesis/Gap Statement. We assumed that solid-state fermentation products of R. astragali and Paecilomyces cicadidae (RPF) could ameliorate diabetic nephropathy and modulate gut microbiota composition. We aimed to study the function and mechanism of the RPF for ameliorating DN in mice. We investigated the effect of the potential roles of RPF in DN mice and interaction between DN and gut microbiota using animal experiments and gut microbiota measurements. We found that RPF dramatically reduced urine protein, serum creatinine and blood urea nitrogen in DN mice. Furthermore, RPF ameliorated the physiological condition of DN mice by regulating the abundance of intestinal microbiota such as Ruminococcaceae_UCG-014, Allobaculum, Unclassified_f__Lachnospiraceae Alloprevotella and Bacteroides. RPF can ameliorate diabetic nephropathy and modulate gut microbiota composition.

Alterations of the Gut Microbiota in Patients with Diabetic Nephropathy.

Diabetic nephropathy (DN) is the primary cause of end-stage renal disease. Accumulating studies have implied a critical role for the gut microbiota in diabetes mellitus (DM) and DN. However, the precise roles and regulatory mechanisms of the gut microbiota in the pathogenesis of DN remain largely unclear. In this study, metagenomics sequencing was performed using fecal samples from healthy controls (CON) and type 2 diabetes mellitus (T2DM) patients with or without DN. Fresh fecal samples from 15 T2DM patients without DN, 15 DN patients, and 15 age-, gender-, and body mass index (BMI)-matched healthy controls were collected. The compositions and potential functions of the gut microbiota were estimated. Although no difference of gut microbiota α and ß diversity was observed between the CON, T2DM, and DN groups, the relative abundances of butyrate-producing bacteria (Clostridium, Eubacterium, and Roseburia intestinalis) and potential probiotics (Lachnospira and Intestinibacter) were significantly reduced in T2DM and DN patients. Besides, Bacteroides stercoris was significantly enriched in fecal samples from patients with DN. Moreover, Clostridium sp. 26_22 was negatively associated with serum creatinine (P < 0.05). DN patients could be accurately distinguished from CON by Clostridium sp. CAG_768 (area under the curve [AUC] = 0.941), Bacteroides propionicifaciens (AUC = 0.905), and Clostridium sp. CAG_715 (AUC = 0.908). DN patients could be accurately distinguished from T2DM patients by Pseudomonadales, Fusobacterium varium, and Prevotella sp. MSX73 (AUC = 0.889). Regarding the potential bacterial functions of the gut microbiota, the citrate cycle, base excision repair, histidine metabolism, lipoic acid metabolism, and bile acid biosynthesis were enriched in DN patients, while selenium metabolism and branched-chain amino acid biosynthesis were decreased in DN patients. IMPORTANCE Gut microbiota imbalance is found in fecal samples from DN patients, in which Roseburia intestinalis is significantly decreased, while Bacteroides stercoris is increased. There is a significant correlation between gut microbiota imbalance and clinical indexes related to lipid metabolism, glucose metabolism, and renal function. The gut microbiota may be predictive factors for the development and progression of DN, although further studies are warranted to illustrate their regulatory mechanisms.

QiDiTangShen granules modulated the gut microbiome composition and improved bile acid profiles in a mouse model of diabetic nephropathy.

QiDiTangShen granules (QDTS), a traditional Chinese herbal medicine, have been used in clinical practice for treating diabetic kidney disease for several years. In our previous study, we have demonstrated that QDTS displayed good efficacy on reducing proteinuria in mice with diabetic nephropathy (DN). However, the exact mechanism by which QDTS exerts its reno-protection remains largely unknown. To ascertain whether QDTS could target the gut microbiota-bile acid axis, the db/db mice were adopted as a mouse model of DN. After a 12-week of treatment, we found that QDTS significantly reduced urinary albumin excretion (UAE), and attenuated the pathological injuries of kidney in the db/db mice, while the body weight and blood glucose levels of those mice were not affected. In addition, we found that QDTS significantly altered the gut microbiota composition, and decreased serum levels of total bile acid (TBA) and BA profiles such as ß-muricholic acid (ß-MCA), taurocholic acid (TCA), tauro ß-muricholic acid (Tß-MCA) and deoxycholic acid (DCA). These BAs are associated with the activation of farnesoid X receptor (FXR), which is highly expressed in kidney. However, there was no significant difference between QDTS-treated and -untreated db/db mice regarding the renal expression of FXR, indicating that other mechanisms may be involved. Conclusively, our study revealed that QDTS significantly alleviated renal injuries in mice with DN. The gut microbiota-bile acid axis may be an important target for the reno-protection of QDTS in DN, but the specific mechanism merits further study.

Effects of Probiotics on Diabetic Nephropathy: A Systematic Review.

BACKGROUND: Diabetic Nephropathy is a frequent complication of diabetes mellitus due to functional and structural modifications in multiple kidney compartments. Probiotics have risen lately as a forthcoming therapeutic intervention but they have not been systematically evaluated in diabetic nephropathy so far. The aim of this systematic review was to evaluate randomized controlled trials and experimental studies assessing the effect of probiotic supplements on diabetic nephropathy. METHODS: An extensive literature search was conducted through electronic databases (PubMed, Scopus, Cinahl and Medline) with the Medical Subject Headings and entry terms of "diabetic nephropathy", "diabetic renal disease" and "probiotics". The search yielded 116 results, 9 of which met the inclusion criteria for this systematic review. RESULTS: Most of the microorganisms used in the studies belonged to the Lactobacillus and Bifidobacterium genus. The dosage ranged from 2×107 to 6×1010 CFU/ g. The form of the probiotics varied across the studies (capsules, sachets, soy milk, kefir and honey). The majority of the studies demonstrated the benefits of probiotic supplementation on the reduction of inflammation, oxidative stress and on the amelioration of renal function biomarkers in subjects with diabetic nephropathy. No major gastrointestinal adverse events were observed during the intervention time with probiotics. CONCLUSION: Findings of this systematic review demonstrate the positive impact of probiotics on Diabetic Nephropathy without any major adverse events. Moreover, future larger randomized controlled trials with bigger samples and longer follow-up time are deemed necessary for further valid results on the effectiveness of probiotic supplementation on Diabetic Nephropathy.

Dysbiosis of intestinal microbiota mediates tubulointerstitial injury in diabetic nephropathy via the disruption of cholesterol homeostasis.

Background: Our previous study demonstrated that the disruption of cholesterol homeostasis promotes tubulointerstitial injury in diabetic nephropathy (DN). This study aimed to further investigate the effects of gut microbiota dysbiosis on this process and explored its potential mechanism. Methods: Diabetic rats treated with broad-spectrum oral antibiotics or faecal microbiota transplantation (FMT) from the healthy donor group and human kidney 2 (HK-2) cells stimulated with sodium acetate were used to observe the effects of gut microbiota on cholesterol homeostasis. The gut microbiota distribution was measured by 16S rDNA sequencing with faeces. Serum acetate level was examined by gas chromatographic analysis. Protein expression of G protein coupled receptor 43 (GPR43) and molecules involved in cholesterol homeostasis were assessed by immunohistochemical staining, immunofluorescence staining, and Western Blotting. Results: Depletion of gut microbiota significantly attenuated albuminuria and tubulointerstitial injury. Interestingly, serum acetate levels were also markedly decreased in antibiotics-treated diabetic rats and positively correlated with the cholesterol contents in kidneys. An in vitro study demonstrated that acetate significantly increased cholesterol accumulation in HK-2 cells, which was caused by increased expression of proteins mainly modulating cholesterol synthesis and uptake. As expected, FMT effectively decreased serum acetate levels and alleviated tubulointerstitial injury in diabetic rats through overriding the disruption of cholesterol homeostasis. Furthermore, GPR43 siRNA treatment blocked acetate-mediated cholesterol homeostasis dysregulation in HK-2 cells through decreasing the expression of proteins governed cholesterol synthesis and uptake. Conclusion: Our studies for the first time demonstrated that the acetate produced from gut microbiota mediated the dysregulation of cholesterol homeostasis through the activation of GPR43, thereby contributing to the tubulointerstitial injury of DN, suggesting that gut microbiota reprogramming might be a new strategy for DN prevention and therapy.

The potential role of the gut microbiota in modulating renal function in experimental diabetic nephropathy murine models established in same environment.

Recent studies have shown that laboratory murine autoimmunity models under the same environment display different outcomes. We established diabetic nephropathy model mice under the same environment using the classic streptozotocin method. Renal dysfunction was different among the mice. Proteinuria was more significant in the severe proteinuria group (SP) than in the mild proteinuria group (MP). We hypothesized a role for the gut microbiota in the outcome and reproducibility of induced DN models. 16S rDNA gene sequencing technology was used to analyze the differences in the gut microbiota between the two groups. Here, through fecal microbiota transplantation (FMT) and gas chromatography mass spectrometry (GC-MS), we verified the role of the gut microbiota and its short-chain fatty acid (SCFA) generation in DN mouse renal dysfunction. In the SP group, there was a reduced abundance of Firmicutes (P < 0.0001), and the dominant genus Allobaculum [linear discriminant analysis (LDA) >3, P < 0.05] was positively correlated with body weight (Rho = 0.767, P < 0.01) and blood glucose content (Rho = 0.648, P < 0.05), while the dominant genus Anaerosporobacter (LDA > 3, P < 0.05) was positively correlated with 24-hour urinary protein content (Rho = 0.773, P < 0.01). In the MP group, the dominant genus Blautia (LDA > 3, P < 0.05) was negatively correlated with 24-hour urinary protein content (Rho = -0.829, P < 0.05). The results indicated that Allobaculum and Anaerosporobacter may worsen renal function, while Blautia may be a protective factor in DN. These findings suggested that the gut microbiota may contribute to the heterogeneity of the induced response since we observed potential disease-associated microbial taxonomies and correlations with DN.

Tangshen formula modulates gut Microbiota and reduces gut-derived toxins in diabetic nephropathy rats.

Growing evidence shows that diabetic kidney disease (DKD) is linked with intestinal dysbiosis from gut-derived toxins. Tangshen Formula (TSF) is a traditional Chinese herbal medicine that has been used to treat DKD. In this study, streptozotocin injection and uninephrectomy-induced diabetic nephropathy (DN) rat model was established to explore the impact of TSF on gut microbiota composition, gut-derived toxins, and the downstream inflammatory pathway of urotoxins in the kidney. TSF treatment for 12 weeks showed significant attenuation of both renal histologic injuries and urinary excretion of albumin compared with DN rats without treatment. TSF treatment also reconstructed gut dysbiosis and reduced levels of indoxyl sulfate and metabolic endotoxemia/lipopolysaccharide. MCP-1 and TNF-α were decreased by TSF both in the serum and kidney. In addition, we revealed that the inhibitory effect of TSF on renal inflammation was associated with the inhibition of aryl hydrocarbon, a receptor of indoxyl sulfate, and TLR4, thereby inhibiting JNK and NF-κB signaling in the kidney. Spearman correlation analysis found that a cluster of gut bacterial phyla and genera were significantly correlated with renal pathology, renal function, and systemic inflammation. In conclusion, orally administered TSF significantly inhibited diabetic renal injury, and modulated gut microbiota, which decreased levels of lipopolysaccharide and indoxyl sulfate, and attenuated renal inflammation. Our results indicate that TSF may be used as an agent in the prevention of gut dysbiosis and elimination of intestinal toxins in DN individuals.

Antifungal susceptibility of oral isolates of Candida species from chronic kidney disease patients on chronic dialysis.

Chronic renal disease patients under chronic dialysis (CRDD) have a multifactorial immunological deterioration with an increased risk of Candida infections. Incidence of Candida infections is increasing. Choice of suitable antifungal agents is limited due to the resistance of some species to several antifungals. Aim of the present study was to identify the distribution and antifungal susceptibility patterns of oral isolated Candida species from infected and colonized patients, as well as to investigate the risk factors for oral infection in patients on dialysis. Cross-sectional study, approved by the institutional bioethics committees was performed in CRDD patients. Demographic, clinic data, and oral mucosa samples were obtained. Infection diagnosis was established clinically and confirmed with exfoliative cytology, each sample was plated on CHROMagar Candida and incubated at 36°C for 2 days. Yeast species were identified by carbohydrate assimilation ID 32C AUX system and the apiweb database. For the antifungal susceptibility test, the M44 A-3 method (CLSI) using fluconazole (FCZ), miconazole (MCZ), nystatin (NYS), and voriconazole (VCZ). Study included 119 participants, the main cause of CRD was nephropathy due to DM2 (58%), and three-fourths of the patients were under hemodialysis. Candida prevalence was 56.3% of 67 colonized or infected patients, 88 isolates were obtained. Principal identified species were C. albicans (51.1%), C. glabrata (25%), and C. tropicalis (14.8%). C. glabrata showed a reduced response to FCZ in 50% of isolates and C. albicans had a reduced response in 16% of the isolates. Antifungal agent with the least efficacious response or with the lowest susceptibility in the isolates of these patients was MCZ, followed by VCZ and FCZ, whereas NYS induced the best antifungal response.