scholarly journals Diet posttranslationally modifies the mouse gut microbial proteome to modulate renal function

Science ◽  
2020 ◽  
Vol 369 (6510) ◽  
pp. 1518-1524 ◽  
Author(s):  
Lior Lobel ◽  
Y. Grace Cao ◽  
Kathrin Fenn ◽  
Jonathan N. Glickman ◽  
Wendy S. Garrett
Keyword(s):  
Chronic Kidney Disease ◽  
Dietary Protein ◽  
Posttranslational Modification ◽  
Bacterial Production ◽  
Microbial Community Composition ◽  
Uremic Toxin ◽  
Sulfur Amino Acid ◽  
Production Of Hydrogen ◽  
Tryptophanase Activity ◽  
Underlying Mechanisms

Associations between chronic kidney disease (CKD) and the gut microbiota have been postulated, yet questions remain about the underlying mechanisms. In humans, dietary protein increases gut bacterial production of hydrogen sulfide (H2S), indole, and indoxyl sulfate. The latter are uremic toxins, and H2S has diverse physiological functions, some of which are mediated by posttranslational modification. In a mouse model of CKD, we found that a high sulfur amino acid–containing diet resulted in posttranslationally modified microbial tryptophanase activity. This reduced uremic toxin–producing activity and ameliorated progression to CKD in the mice. Thus, diet can tune microbiota function to support healthy host physiology through posttranslational modification without altering microbial community composition.

scholarly journals Diet Post-translationally Modifies The Gut Microbial Proteome To Modulate Renal Function

2020 ◽  
Author(s):  
Lior Lobel ◽  
Y. Grace Cao ◽  
Jonathan N. Glickman ◽  
Wendy S. Garrett
Keyword(s):  
Renal Function ◽  
Dietary Intervention ◽  
Microbial Community Composition ◽  
Dietary Modification ◽  
Preclinical Model ◽  
Uremic Toxin ◽  
Post Translational Modification ◽  
Ckd Progression ◽  
Microbial Enzyme ◽  
Tryptophanase Activity

ABSTRACTWe identify a novel mechanism linking diet, gut microbial metabolism, and renal function. We found that a sulfur amino acid-based dietary intervention post-translationally modifies a microbial enzyme, blunting its uremic toxin-producing activity and alleviating chronic kidney disease (CKD) in a preclinical model. We also define a heretofore unknown role for the post-translational modification S-sulfhydration within the gut microbiome. This study provides a framework for understanding how diet can tune microbiota function via protein post-translational modification without altering microbial community composition to support healthy host physiology beyond the gut and specifically how a dietary modification can inhibit tryptophanase activity to ameliorate CKD progression.One Sentence SummaryWe found that diet post-translationally modifies the gut microbiota proteome to modulate kidney function.

Does Vitamin K Intake Influence High Phosphate Induced Vascular Pseudo-ossification: An Underappreciated Therapeutic Prospect in General Population?

2019 ◽  
Vol 20 (4) ◽  
pp. 421-430
Author(s):  
Zar Chi Thent ◽  
Gabriele R.A. Froemming ◽  
Suhaila Abd Muid
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Vascular Calcification ◽  
Vitamin K ◽  
Prolonged Exposure ◽  
Vascular Complication ◽  
Key Factors ◽  
The Matrix ◽  
Underlying Mechanisms ◽  
High Phosphate

Increasing interest in vascular pseudo-ossification has alarmed the modern atherosclerotic society. High phosphate is one of the key factors in vascular pseudo ossification, also known as vascular calcification. The active process of deposition of the phosphate crystals in vascular tissues results in arterial stiffness. High phosphate condition is mainly observed in chronic kidney disease patients. However, prolonged exposure with high phosphate enriched foods such as canned drinks, dietary foods, etc. can be considered as modifiable risk factors for vascular complication in a population regardless of chronic kidney disease. High intake of vitamin K regulates the vascular calcification by exerting its anti-calcification effect. The changes in serum phosphate and vitamin K levels in a normal individual with high phosphate intake are not well investigated. This review summarised the underlying mechanisms of high phosphate induced vascular pseudo ossification such as vascular transdifferentiation, vascular apoptosis and phosphate uptake by sodium-dependent co-transporters. Pubmed, Science Direct, Scopus, ISI Web of Knowledge and Google Scholar were searched using the terms ‘vitamin K’, ‘vascular calcification, ‘phosphate’, ‘transdifferentiation’ and ‘vascular pseudoossification’. Vitamin K certainly activates the matrix GIA protein and inhibits vascular transition and apoptosis in vascular pseudo-ossification. The present view highlighted the possible therapeutic linkage between vitamin K and the disease. Understanding the role of vitamin K will be considered as potent prophylaxis agent against the vascular disease in near future.

scholarly journals Uremic toxin indoxyl sulfate promotes proinflammatory macrophage activation by regulation of β-catenin and YAP pathways

2021 ◽  
Author(s):  
Ying Li ◽  
Jing Yan ◽  
Minjia Wang ◽  
Jing Lv ◽  
Fei Yan ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Inflammatory Response ◽  
Macrophage Polarization ◽  
Indoxyl Sulfate ◽  
Uremic Toxin ◽  
Lps Challenge ◽  
Hla Dr ◽  
M1 Macrophage

AbstractEvidence has been shown that indoxyl sulfate (IS) could impair kidney and cardiac functions. Moreover, macrophage polarization played important roles in chronic kidney disease and cardiovascular disease. IS acts as a nephron-vascular toxin, whereas its effect on macrophage polarization during inflammation is still not fully elucidated. In this study, we aimed to investigate the effect of IS on macrophage polarization during lipopolysaccharide (LPS) challenge. THP-1 monocytes were incubated with phorbol 12-myristate-13-acetate (PMA) to differentiate into macrophages, and then incubated with LPS and IS for 24 h. ELISA was used to detect the levels of TNFα, IL-6, IL-1β in THP-1-derived macrophages. Western blot assay was used to detect the levels of arginase1 and iNOS in THP-1-derived macrophages. Percentages of HLA-DR-positive cells (M1 macrophages) and CD206-positive cells (M2 macrophages) were detected by flow cytometry. IS markedly increased the production of the pro-inflammatory factors TNFα, IL-6, IL-1β in LPS-stimulated THP-1-derived macrophages. In addition, IS induced M1 macrophage polarization in response to LPS, as evidenced by the increased expression of iNOS and the increased proportion of HLA-DR+ macrophages. Moreover, IS downregulated the level of β-catenin, and upregulated the level of YAP in LPS-stimulated macrophages. Activating β-catenin signaling or inhibiting YAP signaling suppressed the IS-induced inflammatory response in LPS-stimulated macrophages by inhibiting M1 polarization. IS induced M1 macrophage polarization in LPS-stimulated macrophages via inhibiting β-catenin and activating YAP signaling. In addition, this study provided evidences that activation of β-catenin or inhibition of YAP could alleviate IS-induced inflammatory response in LPS-stimulated macrophages. This finding may contribute to the understanding of immune dysfunction observed in chronic kidney disease and cardiovascular disease.

scholarly journals Uremic Toxins and Frailty in Patients with Chronic Kidney Disease: A Molecular Insight

2021 ◽  
Vol 22 (12) ◽  
pp. 6270
Author(s):  
Chia-Ter Chao ◽  
Shih-Hua Lin
Keyword(s):  
Chronic Kidney Disease ◽  
Renal Function ◽  
Kidney Disease ◽  
Uremic Toxins ◽  
Heme Oxygenase 1 ◽  
Signal Pathways ◽  
Uremic Toxin ◽  
Nuclear Factor ◽  
Cognitive Frailty ◽  
Renal Function Decline

The accumulation of uremic toxins (UTs) is a prototypical manifestation of uremic milieu that follows renal function decline (chronic kidney disease, CKD). Frailty as a potential outcome-relevant indicator is also prevalent in CKD. The intertwined relationship between uremic toxins, including small/large solutes (phosphate, asymmetric dimethylarginine) and protein-bound ones like indoxyl sulfate (IS) and p-cresyl sulfate (pCS), and frailty pathogenesis has been documented recently. Uremic toxins were shown in vitro and in vivo to induce noxious effects on many organ systems and likely influenced frailty development through their effects on multiple preceding events and companions of frailty, such as sarcopenia/muscle wasting, cognitive impairment/cognitive frailty, osteoporosis/osteodystrophy, vascular calcification, and cardiopulmonary deconditioning. These organ-specific effects may be mediated through different molecular mechanisms or signal pathways such as peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), mitogen-activated protein kinase (MAPK) signaling, aryl hydrocarbon receptor (AhR)/nuclear factor-κB (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Runt-related transcription factor 2 (RUNX2), bone morphogenic protein 2 (BMP2), osterix, Notch signaling, autophagy effectors, microRNAs, and reactive oxygen species induction. Anecdotal clinical studies also suggest that frailty may further accelerate renal function decline, thereby augmenting the accumulation of UTs in affected individuals. Judging from these threads of evidence, management strategies aiming for uremic toxin reduction may be a promising approach for frailty amelioration in patients with CKD. Uremic toxin lowering strategies may bear the potential of improving patients’ outcomes and restoring their quality of life, through frailty attenuation. Pathogenic molecule-targeted therapeutics potentially disconnect the association between uremic toxins and frailty, additionally serving as an outcome-modifying approach in the future.

scholarly journals Indoxyl-Sulfate-Induced Redox Imbalance in Chronic Kidney Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 936
Author(s):  
Chien-Lin Lu ◽  
Cai-Mei Zheng ◽  
Kuo-Cheng Lu ◽  
Min-Tser Liao ◽  
Kun-Lin Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Muscle Wasting ◽  
Mesangial Cells ◽  
Target Organ Damage ◽  
Organ Damage ◽  
Indoxyl Sulfate ◽  
Uremic Toxin ◽  
Tubulointerstitial Injury

The accumulation of the uremic toxin indoxyl sulfate (IS) induces target organ damage in chronic kidney disease (CKD) patients, and causes complications including cardiovascular diseases, renal osteodystrophy, muscle wasting, and anemia. IS stimulates reactive oxygen species (ROS) production in CKD, which impairs glomerular filtration by a direct cytotoxic effect on the mesangial cells. IS further reduces antioxidant capacity in renal proximal tubular cells and contributes to tubulointerstitial injury. IS-induced ROS formation triggers the switching of vascular smooth muscular cells to the osteoblastic phenotype, which induces cardiovascular risk. Low-turnover bone disease seen in early CKD relies on the inhibitory effects of IS on osteoblast viability and differentiation, and osteoblastic signaling via the parathyroid hormone. Excessive ROS and inflammatory cytokine releases caused by IS directly inhibit myocyte growth in muscle wasting via myokines’ effects. Moreover, IS triggers eryptosis via ROS-mediated oxidative stress, and elevates hepcidin levels in order to prevent iron flux in circulation in renal anemia. Thus, IS-induced oxidative stress underlies the mechanisms in CKD-related complications. This review summarizes the underlying mechanisms of how IS mediates oxidative stress in the pathogenesis of CKD’s complications. Furthermore, we also discuss the potential role of oral AST-120 in attenuating IS-mediated oxidative stress after gastrointestinal adsorption of the IS precursor indole.

scholarly journals Synbiotics Alleviate the Gut Indole Load and Dysbiosis in Chronic Kidney Disease

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 114
Author(s):  
Chih-Yu Yang ◽  
Ting-Wen Chen ◽  
Wan-Lun Lu ◽  
Shih-Shin Liang ◽  
Hsien-Da Huang ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Gut Microbiota ◽  
Statistical Significance ◽  
Additional Treatment ◽  
Indoxyl Sulfate ◽  
Uremic Toxin ◽  
Healthy Controls ◽  
Gut Dysbiosis ◽  
Novel Concept

Chronic kidney disease (CKD) has long been known to cause significant digestive tract pathology. Of note, indoxyl sulfate is a gut microbe-derived uremic toxin that accumulates in CKD patients. Nevertheless, the relationship between gut microbiota, fecal indole content, and blood indoxyl sulfate level remains unknown. In our study, we established an adenine-induced CKD rat model, which recapitulates human CKD-related gut dysbiosis. Synbiotic treatment in CKD rats showed a significant reduction in both the indole-producing bacterium Clostridium and fecal indole amount. Furthermore, gut microbiota diversity was reduced in CKD rats but was restored after synbiotic treatment. Intriguingly, in our end-stage kidney disease (ESKD) patients, the abundance of indole-producing bacteria, Bacteroides, Prevotella, and Clostridium, is similar to that of healthy controls. Consistently, the fecal indole tends to be higher in the ESKD patients, but the difference did not achieve statistical significance. However, the blood level of indoxyl sulfate was significantly higher than that of healthy controls, implicating that under an equivalent indole production rate, the impaired renal excretion contributes to the accumulation of this notorious uremic toxin. On the other hand, we did identify two short-chain fatty acid-producing bacteria, Faecalibacterium and Roseburia, were reduced in ESKD patients as compared to the healthy controls. This may contribute to gut dysbiosis. We also identified that three genera Fusobacterium, Shewanella, and Erwinia, in the ESKD patients but not in the healthy controls. Building up gut symbiosis to treat CKD is a novel concept, but once proved effective, it will provide an additional treatment strategy for CKD patients.

Abstract 17220: Effects of the Oral Adsorbent of AST-120 in Patients with both Chronic Heart Failure and Chronic Kidney Disease

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Miki Imazu ◽  
Masanori Asakura ◽  
Takuya Hasegawa ◽  
Hiroshi Asanuma ◽  
Shin Ito ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Kidney Disease ◽  
Chronic Heart Failure ◽  
Kidney Disease ◽  
Diastolic Dysfunction ◽  
Uremic Toxins ◽  
Control Group ◽  
Blood Levels ◽  
Uremic Toxin ◽  
Oral Adsorbent

Background: One of uremic toxins, indoxyl sulfate (IS) is related to the progression of chronic kidney disease (CKD) and the worse cardiovascular outcomes. We have previously reported the relationship between IS levels and the severity of chronic heart failure (CHF), but the question arises as to whether the treatment of uremic toxin is beneficial in patients with CHF. This study aimed to elucidate whether the treatment with the oral adsorbent which reduces uremic toxin improved the cardiac function of the patients with CHF. Methods: First of all, we retrospectively enrolled 49 patients with both CHF and stage ≤3 CKD in our institute compared with the healthy subjects without CHF or CKD in the resident cohort study of Arita. Secondly, we retrospectively enrolled 16 CHF outpatients with stage 3-5 CKD. They were treated with and without the oral adsorbent of AST-120 for one year termed as the treatment and control groups, respectively. We underwent both blood test and echocardiography before and after the treatment. Results: First of all, among 49 patients in CHF patients, plasma IS levels increased to 1.38 ± 0.84 μg/ml from the value of 0.08 ± 0.06 μg/ml in Arita-cho as a community-living matched with gender and eGFR of CHF patients. We found both fractional shortening (FS) and E/e’, an index of diastolic function were decreased (25.0 ± 12.7%) and increased (13.7 ± 7.5), respectively in CHF patients compared with the value of FS and E/e’ in Arita-cho (FS: 41.8 ± 8.3%, E/e’: 8.8 ± 2.1). Secondly, in the treatment group, the plasma IS levels and the serum creatinine and brain natriuretic peptide levels decreased (1.40 ± 0.17 to 0.92 ± 0.15 μg/ml; p<0.05, 1.91 ± 0.16 to 1.67 ± 0.12 mg/dl; p<0.05, 352 ± 57 to 244 ± 49 pg/ml; p<0.05, respectively) and both FS and E/e’ were improved following the treatment with AST-120 (28.8 ± 2.8 to 32.9 ± 2.6%; p<0.05, 18.0 ± 2.0 to 11.8 ± 1.0; p<0.05). However, these parameters did not change in the control group. Conclusions: The treatment to decrease the blood levels of uremic toxins improved not only renal dysfunction but cardiac systolic and diastolic dysfunction in patients with chronic heart failure. Oral adsorbents might be a new treatment of heart failure especially with diastolic dysfunction.

Abstract 109: Gamma-adducin Effects on Microvascular Function- a Common Link of Hypertension Induced Chronic Kidney Disease and Cognitive Impairments

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Fan Fan ◽  
Shaoxun Wang ◽  
Paige N Mims ◽  
Chao Zhang ◽  
Richard J Roman
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Genetic Model ◽  
Cognitive Impairments ◽  
Microvascular Dysfunction ◽  
Small Region ◽  
Glomerular Injury ◽  
Flow Pressure ◽  
Underlying Mechanisms ◽  
Stop Flow

Chronic kidney disease (CKD) and cognitive impairments are common complications of hypertension. Increasing evidence suggests that the cognitive impairments associated with CKD may be related to microvascular dysfunction, however, the underlying mechanisms remain to be elucidated. FHH is a genetic model of hypertension-induced nephropathy. We found that the myogenic response and autoregulation of the renal and cerebral circulation is impaired in FHH rats, and was restored in a FHH.1 BN congenic strain in which a small region of Chr. 1 containing 15 genes, including Add3, from BN rats was transferred into the FHH background. The present study examined whether Add3 contributes to hypertension related CKD, and is associated with the development of cognitive impairments due to microvascular dysfunction. FHH rats exhibited impaired autoregulation of RBF in comparison with FHH.1 BN rats. Pgc estimated from the stop flow pressure increased by 20 mmHg in FHH rats when RPP was increased from 100 to 140 mmHg versus only 4 mmHg in FHH.1 BN . FHH rats developed severe renal injury, and proteinuria rose from 37 ± 2 to 260 ± 32 mg/day as they aged from 12 to 21 weeks, but rose by a significant lesser extent in FHH.1 BN and FHH.Add3 rats. Glomerular injury scores were 3.31 ± 0.01, 2.54 ± 0.01 and 2.50 ± 0.03, and areas of fibrosis in renal cortex were 23.57 ± 1.04%, 8.28 ± 0.33 and 4.71 ± 0.3 in DOCA/salt induced hypertensive FHH, FHH.1 BN and FHH.Add3 rats, respectively. CBF rose by 99 ± 7%, 64 ± 5% and 42 ± 4% in FHH, FHH.1 BN and FHH.Add3 rats, respectively, when MAP was increased from 100 to 190 mmHg, demonstrating impaired autoregulation of CBF in FHH rats was partially rescued with the replacement of wildtype Add3. BBB leakage was greater in FHH rats than in FHH.1 BN and FHH.Add3 rats, and hypertensive FHH rats exhibited marked neurodegeneration and vascular remodeling of the neocortex and hippocampus. The hypertensive FHH rats took 2.5 times longer time to escape from an eight-arm water maze in comparison to FHH.1 BN rats suggesting cognitive deficit. These results indicate that Add3 may play a role in the development of hypertension related CKD and cognitive impairments in FHH rats associated with microvascular dysfunction.

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