Understanding the gut–kidney axis in nephrolithiasis: an analysis of the gut microbiota composition and functionality of stone formers

Gut ◽  
2018 ◽  
Vol 67 (12) ◽  
pp. 2097-2106 ◽  
Author(s):  
Andrea Ticinesi ◽  
Christian Milani ◽  
Angela Guerra ◽  
Franca Allegri ◽  
Fulvio Lauretani ◽  
...  

ObjectivesThe involvement of the gut microbiota in the pathogenesis of calcium nephrolithiasis has been hypothesised since the discovery of the oxalate-degrading activity of Oxalobacter formigenes, but never comprehensively studied with metagenomics. The aim of this case–control study was to compare the faecal microbiota composition and functionality between recurrent idiopathic calcium stone formers (SFs) and controls.DesignFaecal samples were collected from 52 SFs and 48 controls (mean age 48±11). The microbiota composition was analysed through 16S rRNA microbial profiling approach. Ten samples (five SFs, five controls) were also analysed with deep shotgun metagenomics sequencing, with focus on oxalate-degrading microbial metabolic pathways. Dietary habits, assessed through a food-frequency questionnaire, and 24-hour urinary excretion of prolithogenic and antilithogenic factors, including calcium and oxalate, were compared between SFs and controls, and considered as covariates in the comparison of microbiota profiles.ResultsSFs exhibited lower faecal microbial diversity than controls (Chao1 index 1460±363vs 1658±297, fully adjusted p=0.02 with stepwise backward regression analysis). At multivariate analyses, three taxa (Faecalibacterium, Enterobacter, Dorea) were significantly less represented in faecal samples of SFs. The Oxalobacter abundance was not different between groups. Faecal samples from SFs exhibited a significantly lower bacterial representation of genes involved in oxalate degradation, with inverse correlation with 24-hour oxalate excretion (r=−0.87, p=0.002). The oxalate-degrading genes were represented in several bacterial species, whose cumulative abundance was inversely correlated with oxaluria (r=−0.85, p=0.02).ConclusionsIdiopathic calcium SFs exhibited altered gut microbiota composition and functionality that could contribute to nephrolithiasis physiopathology.

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Angie Jefferson ◽  
Katie Adolphus

AbstractThe influence on health of the human gut microbiota is increasingly recognised, however wheat fibre, consumed frequently in Western diets has traditionally been considered inert with regard to gut microbiota composition and metabolic activity. We undertook a systematic review (PRISMA methodology) of human intervention studies examining the effects of intact cereal fibres on gut microbiota composition among healthy adults.(1) Studies published in the past 20 years were identified on PubMed and Cochrane electronic databases. Inclusion criteria were: healthy adult participants, at least one intact cereal fibre (or its sub-fraction) and measurement of faecal microbiota related outcomes. Out of forty studies meeting inclusion criteria, seventeen manipulated wheat fibre/bran or its key constituent arabinoxylans (AXOS), and ten used a whole diet approach with predominantly wheat fibre. Results from these twenty seven wheat fibre papers are presented here. Eight studies provided wheat bran/fibre (ranging from 5.7g-21g/day wheat fibre or 13g-28g/day wheat bran). Three reported significant effects on gut microbiota abundance and/or diversity (both at phyla and species level) and one showed no effect. Six reported significant increases in fermentation metabolites and one reported no significant change. Ten studies manipulated whole day fibre intake (predominantly wheat but also permitting some oats, rye and rice). Wholegrain intake ranged from 80g-150 g per day and fibre from 13.7g–40 g per day. Six found significant increases in bacterial diversity and/or abundance and five showed significant increases in fermentation metabolites. Two identified that response to high fibre intervention is dependent on baseline gut microbiota richness - those with limited richness exhibiting greater microbiota change over time in response to fibre increase. Two reported no significant effects. Nine studies utilised manipulation of AXOS (2.2g–18.8 g per day) with five demonstrating significant increases in target bacterial species and six significant increases in fermentation metabolites. One reported no significant effect to faecal metabolites. This review supports a role for the wheat fibre found in everyday foods (such as bran breakfast cereal of high fibre breads) promoting both microbiota diversity and abundance. While the healthy microbiome is yet to be defined, consumption of a single daily serving of wheat bran fibre appears sufficient to effect gut microbiota fermentation (with demonstrable effects arising from as low as 6g/day), and promote species diversity, with potential benefit to health.However exploration of stability over longer time frames (> 12 weeks) is now required.


Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 748 ◽  
Author(s):  
Jin-Young Lee ◽  
Mohamed Mannaa ◽  
Yunkyung Kim ◽  
Jehun Kim ◽  
Geun-Tae Kim ◽  
...  

The aim of this study was to investigate differences between the gut microbiota composition in patients with rheumatoid arthritis (RA) and those with osteoarthritis (OA). Stool samples from nine RA patients and nine OA patients were collected, and DNA was extracted. The gut microbiome was assessed using 16S rRNA gene amplicon sequencing. The structures and differences in the gut microbiome between RA and OA were analyzed. The analysis of diversity revealed no differences in the complexity of samples. The RA group had a lower Bacteroidetes: Firmicutes ratio than did the OA group. Lactobacilli and Prevotella, particularly Prevotella copri, were more abundant in the RA than in the OA group, although these differences were not statistically significant. The relative abundance of Bacteroides and Bifidobacterium was lower in the RA group. At the species level, the abundance of certain bacterial species was significantly lower in the RA group, such as Fusicatenibacter saccharivorans, Dialister invisus, Clostridium leptum, Ruthenibacterium lactatiformans, Anaerotruncus colihominis, Bacteroides faecichinchillae, Harryflintia acetispora, Bacteroides acidifaciens, and Christensenella minuta. The microbial properties of the gut differed between RA and OA patients, and the RA dysbiosis revealed results similar to those of other autoimmune diseases, suggesting that a specific gut microbiota pattern is related to autoimmunity.


Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3408
Author(s):  
Samar Y. Ahmad ◽  
James Friel ◽  
Dylan Mackay

Non-nutritive artificial sweeteners (NNSs) may have the ability to change the gut microbiota, which could potentially alter glucose metabolism. This study aimed to determine the effect of sucralose and aspartame consumption on gut microbiota composition using realistic doses of NNSs. Seventeen healthy participants between the ages of 18 and 45 years who had a body mass index (BMI) of 20–25 were selected. They undertook two 14-day treatment periods separated by a four-week washout period. The sweeteners consumed by each participant consisted of a standardized dose of 14% (0.425 g) of the acceptable daily intake (ADI) for aspartame and 20% (0.136 g) of the ADI for sucralose. Faecal samples collected before and after treatments were analysed for microbiome and short-chain fatty acids (SCFAs). There were no differences in the median relative proportions of the most abundant bacterial taxa (family and genus) before and after treatments with both NNSs. The microbiota community structure also did not show any obvious differences. There were no differences in faecal SCFAs following the consumption of the NNSs. These findings suggest that daily repeated consumption of pure aspartame or sucralose in doses reflective of typical high consumption have minimal effect on gut microbiota composition or SCFA production.


2020 ◽  
Author(s):  
Taís Silveira Assmann ◽  
Amanda Cuevas-Sierra ◽  
José Ignacio Riezu-Boj ◽  
Fermin Milagro ◽  
J Alfredo Martínez

Abstract Background: Unbalances in microRNAs (miRNA) and gut microbiota patterns have been proposed as putative factors concerning onset and development of obesity and other metabolic diseases. However, the determinants that mediate the interactions between miRNAs and the gut microbiome impacting on obesity are scarcely understood. Thus, the aim of this article was to investigate possible interactions between circulating miRNAs and gut microbiota composition in obesity. Method: The analyzed sample comprised 78 subjects with obesity [cases, body mass index (BMI): 30 – 40 kg/m2] and 25 eutrophic individuals (controls, BMI £ 25 kg/m2). The expression of 96 miRNAs was investigated in plasma of all individuals using miRCURY LNA miRNA Custom PCR Panels (Exiqon). Bacterial DNA sequencing was performed following the Illumina 16S protocol. The FDR (Benjamini-Hochberg test, q-value) correction was used for multiple comparison analyses.Results: A total of 26 circulating miRNAs and 12 bacterial species were found differentially expressed between cases and controls. Interestingly, an interaction among three miRNAs (miR-130b-3p, miR-185-5p, and miR-21-5p) with Bacteroides eggerthi, and BMI levels was evidenced (r2= 0.148, P= 0.004). Those miRNAs that correlated with obesity-associated gut bacteria abundance are known to regulate target genes that participate in metabolism-related pathways, such as fatty acid degradation, carbohydrate digestion and absorption, insulin signaling, and glycerolipid metabolism. Conclusion: This study characterized an interaction between the abundance of 4 bacterial species and 14 circulating miRNAs in relation to body adiposity. Moreover, the current study also suggests that miRNAs may serve as a communication mechanism between the gut microbiome and human hosts. Clinical trial registration: clinicaltrials.gov (reg. no. NCT02737267).


2021 ◽  
Vol 22 (9) ◽  
pp. 4692
Author(s):  
Anna Ferrulli ◽  
Lorenzo Drago ◽  
Sara Gandini ◽  
Stefano Massarini ◽  
Federica Bellerba ◽  
...  

Growing evidence highlights the crucial role of gut microbiota in affecting different aspects of obesity. Considering the ability of deep transcranial magnetic stimulation (dTMS) to modulate the cortical excitability, the reward system, and, indirectly, the autonomic nervous system (ANS), we hypothesized a potential role of dTMS in affecting the brain-gut communication pathways, and the gut microbiota composition in obesity. In a hospital setting, 22 subjects with obesity (5 M, 17 F; 44.9 ± 2.2 years; BMI 37.5 ± 1.0 kg/m2) were randomized into three groups receiving 15 sessions (3 per week for 5 weeks) of high frequency (HF), low frequency (LF) dTMS, or sham stimulation. Fecal samples were collected at baseline and after 5 weeks of treatment. Total bacterial DNA was extracted from fecal samples using the QIAamp DNA Stool Mini Kit (Qiagen, Italy) and analyzed by a metagenomics approach (Ion Torrent Personal Genome Machine). After 5 weeks, a significant weight loss was found in HF (HF: −4.1 ± 0.8%, LF: −1.9 ± 0.8%, sham: −1.3 ± 0.6%, p = 0.042) compared to LF and sham groups, associated with a decrease in norepinephrine compared to baseline (HF: −61.5 ± 15.2%, p < 0.01; LF: −31.8 ± 17.1%, p < 0.05; sham: −35.8 ± 21.0%, p > 0.05). Furthermore, an increase in Faecalibacterium (+154.3% vs. baseline, p < 0.05) and Alistipes (+153.4% vs. baseline, p < 0.05) genera, and a significant decrease in Lactobacillus (−77.1% vs. baseline, p < 0.05) were found in HF. Faecalibacterium variations were not significant compared to baseline in the other two groups (LF: +106.6%, sham: +27.6%; p > 0.05) as well as Alistipes (LF: −54.9%, sham: −15.1%; p > 0.05) and Lactobacillus (LF: −26.0%, sham: +228.3%; p > 0.05) variations. Norepinephrine change significantly correlated with Bacteroides (r2 = 0.734; p < 0.05), Eubacterium (r2 = 0.734; p < 0.05), and Parasutterella (r2 = 0.618; p < 0.05) abundance variations in HF. In conclusion, HF dTMS treatment revealed to be effective in modulating gut microbiota composition in subjects with obesity, reversing obesity-associated microbiota variations, and promoting bacterial species representative of healthy subjects with anti-inflammatory properties.


2020 ◽  
Vol 21 (24) ◽  
pp. 9509
Author(s):  
Taís Silveira Assmann ◽  
Amanda Cuevas-Sierra ◽  
José Ignacio Riezu-Boj ◽  
Fermín I. Milagro ◽  
J. Alfredo Martínez

Background: The determinants that mediate the interactions between microRNAs and the gut microbiome impacting on obesity are scarcely understood. Thus, the aim of this study was to investigate possible interactions between circulating microRNAs and gut microbiota composition in obesity. Method: The sample comprised 78 subjects with obesity (cases, body mass index (BMI): 30–40 kg/m2) and 25 eutrophic individuals (controls, BMI ≤ 25 kg/m2). The expression of 96 microRNAs was investigated in plasma of all individuals using miRCURY LNA miRNA Custom PCR Panels. Bacterial DNA sequencing was performed following the Illumina 16S protocol. The FDR correction was used for multiple comparison analyses. Results: A total of 26 circulating microRNAs and 12 bacterial species were found differentially expressed between cases and controls. Interestingly, an interaction among three miRNAs (miR-130b-3p, miR-185-5p and miR-21-5p) with Bacteroides eggerthi and BMI levels was evidenced (r2 = 0.148, p = 0.004). Moreover, these microRNAs regulate genes that participate in metabolism-related pathways, including fatty acid degradation, insulin signaling and glycerolipid metabolism. Conclusions: This study characterized an interaction between the abundance of 4 bacterial species and 14 circulating microRNAs in relation to obesity. Moreover, the current study also suggests that miRNAs may serve as a communication mechanism between the gut microbiome and human hosts.


Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2402
Author(s):  
Emily A. Losno ◽  
Katharina Sieferle ◽  
Federico J. Armando Perez-Cueto ◽  
Christian Ritz

The human gut microbiota are the microorganisms (generally bacteria and archaea) that live in the digestive tracts of humans. Due to their numerous functions, the gut microbiota can be considered a virtual organ of the body, playing a pivotal role in health maintenance. Dietary habits contribute to gut microbiota composition, and evidence from observational and intervention studies suggest that vegan diets may promote health, potentially through affecting the diverse ecosystem of beneficial bacteria in the gut. A systematic literature search was conducted on PubMed and Scopus to identify studies investigating the microbiota composition in vegans. Vegans are defined as people excluding food products that are derived from animals from their diet. Nine observational studies were identified. The main outcome of the systematic review was an increase in Bacteroidetes on the phylum level and a higher abundance of Prevotella on the genus level. In conclusion, the present systematic literature review highlighted some benefits of a vegan diet but also demonstrated the complexity of evaluating results from gut microbiota research. The available evidence only consisted of cross-sectional studies, therefore suggesting the need for well-designed randomised controlled trials. Furthermore, the quality assessment of the studies included in the review suggested a lack of standardised and validated methods for participant selection as well as for faecal sampling and faecal analysis.


2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S39-S40
Author(s):  
Victoria Godfrey ◽  
Hasan Zaki

Abstract The incidence of inflammatory bowel disease (IBD) is strikingly high in Western countries, implicating the role of Western diet in its etiology and pathogenesis. Western diet is characterized by high fat, low fiber, and high sugar. Despite clinical evidence of an association between high sugar diet and IBD susceptibility, the precise role of dietary simple sugars such as glucose, fructose, and sucrose in colitis pathogenesis is unknown. Using dextran sodium sulfate (DSS) and IL10-deficient mouse models of colitis, we studied the effect of simple sugars in colitis susceptibility. Mice were given high glucose, fructose or sucrose in their drinking water or left untreated before and during colitis induced by DSS. Sugar-fed mice exhibited increased colitis susceptibility evidenced by higher body weight loss, diarrhea, rectal bleeding, and severe histopathological changes in the colon as compared to those of sugar-untreated colitic mice. Pre-colitis dietary habit of sugar consumption was critical since sugar pretreated mice were susceptible to DSS-induced colitis even without high sugar diet intake during DSS administration. Consistent with these findings, there were higher incidence of spontaneous colitis development in Il10-/- mice following consumption of high sugar. To understand the underlying mechanism, we evaluated the effect of high sugar diet on intestinal epithelial cell death, inflammation, epithelial barrier permeability, and gut microbiota composition in healthy mice. We did not observe any major pathological changes and apoptosis in the colon of sugar-fed mice. Inflammatory responses, activation of inflammatory signaling pathways, and the expression of tight junction proteins were comparable between control and sugar-fed mice. Interestingly, gut microbiota composition of sugar-fed mice was altered as measured by 16S rRNA gene sequencing of DNA isolated from feces. Microbial species richness was reduced and relative abundance of several bacterial species was either increased or decreased in sugar-fed mice. We further confirmed that sugar-induced alteration of gut microbiota is responsible for exacerbated colitis by using antibiotics or germ-free mice. Mice receiving antibiotics during high-sugar intake did not show increased DSS-colitis susceptibility. Similarly, high-sugar diet did not induce overt colitis pathogenesis in germ-free mice. These findings demonstrate a critical role of dietary caloric sugars in the predisposition and promotion of colitis and could be implicated in the treatment and management of IBD.


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