Faecalibacterium prausnitzii Attenuates CKD via Butyrate-Renal GPR43 Axis.

BACKGROUND: Despite available clinical management strategies, chronic kidney disease (CKD) is associated with severe morbidity and mortality worldwide, which beckons new solutions. Host-microbial interactions with a depletion of Faecalibacterium prausnitzii in CKD are reported. However, the mechanisms about if and how F prausnitzii can be used as a probiotic to treat CKD remains unknown. METHODS: We evaluated the microbial compositions in 2 independent CKD populations for any potential probiotic. Next, we investigated if supplementation of such probiotic in a mouse CKD model can restore gut-renal homeostasis as monitored by its effects on suppression on renal inflammation, improvement in gut permeability and renal function. Last, we investigated the molecular mechanisms underlying the probiotic-induced beneficial outcomes. RESULTS: We observed significant depletion of Faecalibacterium in the patients with CKD in both Western (n=283) and Eastern populations (n=75). Supplementation of F prausnitzii to CKD mice reduced renal dysfunction, renal inflammation, and lowered the serum levels of various uremic toxins. These are coupled with improved gut microbial ecology and intestinal integrity. Moreover, we demonstrated that the beneficial effects in kidney induced by F prausnitzii-derived butyrate were through the GPR (G protein-coupled receptor)-43. CONCLUSIONS: Using a mouse CKD model, we uncovered a novel beneficial role of F prausnitzii in the restoration of renal function in CKD, which is, at least in part, attributed to the butyrate-mediated GPR-43 signaling in the kidney. Our study provides the necessary foundation to harness the therapeutic potential of F prausnitzii for ameliorating CKD.

Washed microbiota transplantation improves haemoglobin levels in anaemia of chronic disease.

BACKGROUND: Anaemia of chronic disease (ACD) is the second most common type of anaemia and lacks an effective treatment. Patients with anaemia are reported to have altered gut microbial profiles, which may affect erythropoiesis. Here, we investigated the gut microbial features of patients with ACD and determined whether regulating gut microbiota using washed microbiota transplantation (WMT) was effective in treating ACD. METHODS: We compared the gut microbiota profile of patients with ACD and healthy controls, evaluated the efficacy of WMT on haematological parameters in the patients, and analysed the alterations in gut microbiota after WMT treatment. RESULTS: Patients with ACD had lower gut microbial richness, and differences in microbial composition and function, relative to healthy controls. Additionally, the relative abundances of two butyrate-producing genera Lachnospiraceae NK4A136 group and Butyricicoccus, were positively correlated with the haemoglobin (HGB) level and lower in patients with ACD than controls. WMT significantly increased HGB levels in patients with ACD. After the first, second and third WMT rounds, normal HGB levels were restored in 27.02%, 27.78% and 36.37% (all p < .05) of patients with ACD, respectively. Moreover, WMT significantly increased the abundance of butyrate-producing genera and downregulated gut microbial functions that were upregulated in patients with ACD. CONCLUSIONS: Patients with ACD exhibited differences in gut microbial composition and function relative to healthy controls. WMT is an effective treatment for ACD that reshapes gut microbial composition, restores butyrate-producing bacteria and regulates the functions of gut microbiota.

Tributyltin(IV) Butyrate: A Novel Epigenetic Modifier with ER Stress- and Apoptosis-Inducing Properties in Colon Cancer Cells.

Organotin(IV) compounds are a class of non-platinum metallo-conjugates exhibiting antitumor activity. The effects of different organotin types has been related to several mechanisms, including their ability to modify acetylation protein status and to promote apoptosis. Here, we focus on triorganotin(IV) complexes of butyric acid, a well-known HDAC inhibitor with antitumor properties. The conjugated compounds were synthesized and characterised by FTIR spectroscopy, multi-nuclear (1H, 13C and 119Sn) NMR, and mass spectrometry (ESI-MS). In the triorganotin(IV) complexes, an anionic monodentate butyrate ligand was observed, which coordinated the tin atom on a tetra-coordinated, monomeric environment similar to ester. FTIR and NMR findings confirm this structure both in solid state and solution. The antitumor efficacy of the triorganotin(IV) butyrates was tested in colon cancer cells and, among them, tributyltin(IV) butyrate (BT2) was selected as the most efficacious. BT2 induced G2/M cell cycle arrest, ER stress, and apoptotic cell death. These effects were obtained using low concentrations of BT2 up to 1 µM, whereas butyric acid alone was completely inefficacious, and the parent compound TBT was poorly effective at the same treatment conditions. To assess whether butyrate in the coordinated form maintains its epigenetic effects, histone acetylation was evaluated and a dramatic decrease in acetyl-H3 and -H4 histones was found. In contrast, butyrate alone stimulated histone acetylation at a higher concentration (5 mM). BT2 was also capable of preventing histone acetylation induced by SAHA, another potent HDAC inhibitor, thus suggesting that it may activate HDACs. These results support a potential use of BT2, a novel epigenetic modulator, in colon cancer treatment.

Effects of Oral Butyrate on Blood Pressure in Patients With Hypertension: A Randomized, Placebo-Controlled Trial.

BACKGROUND: The microbiota-derived short chain fatty acid butyrate has been shown to lower blood pressure (BP) in rodent studies. Nonetheless, the net effect of butyrate on hypertension in humans remains uncovered. In this study, for the first time, we aimed to determine the effect of oral butyrate on BP in patients with hypertension. METHODS: We performed a double-blind randomized placebo-controlled trial including 23 patients with hypertension. Antihypertensive medication was discontinued for the duration of the study with a washout period of 4 weeks before starting the intervention. Participants received daily oral capsules containing either sodium butyrate or placebo with an equivalent dosage of sodium chloride for 4 weeks. The primary outcome was daytime 24-hour systolic BP. Differences between groups over time were assessed using linear mixed models (group-by-time interaction). RESULTS: Study participants (59.0±3.7 years; 56.5% female) had an average baseline office systolic BP of 143.5±14.6 mm Hg and diastolic BP of 93.0±8.3 mm Hg. Daytime 24-hour systolic and diastolic BP significantly increased over the intervention period in the butyrate compared with the placebo group, with an increase of +9.63 (95% CI, 2.02-17.20) mm Hg in daytime 24-hour systolic BP and +5.08 (95% CI, 1.34-8.78) mm Hg in diastolic BP over 4 weeks. Butyrate levels significantly increased in plasma, but not in feces, upon butyrate intake, underscoring its absorption. CONCLUSIONS: Four-week treatment with oral butyrate increased daytime systolic and diastolic BP in subjects with hypertension. Our findings implicate that butyrate does not have beneficial effects on human hypertension, which warrants caution in future butyrate intervention studies. REGISTRATION: URL: https://clinicaltrialregister.nl/nl/trial/22936; Unique identifier: NL8924.

Protective effects of butyrate on cerebral ischaemic injury in animal models: a systematic review and meta-analysis.

Introduction: Cerebral ischaemic stroke is a common disease that poses a serious threat to human health. Butyrate is an important metabolite of intestinal microorganisms. Recent studies have shown that butyrate has a significant protective effect in animal models of cerebral ischaemic injury. Objective: The aim of this study was to evaluate the protective effect of butyrate on cerebral ischaemic stroke by meta-analysis, aiming to provide a scientific basis for the clinical application of butyrate in patients with cerebral ischaemia. Materials and methods: A systematic search was conducted for all relevant studies published before 23 January 2024, in PubMed, Web of Science, Cochrane Library, and Embase. Methodological quality was assessed using Syrcle's risk of bias tool for animal studies. Data were analysed using Rev Man 5.3 software. Results: A total of nine studies were included, and compared with controls, butyrate significantly increased BDNF levels in the brain (SMD = 2.33, 95%CI = [1.20, 3.47], p < 0.005) and P-Akt expression (SMD = 3.53, 95% CI = [0.97, 6.10], p < 0.05). Butyrate also decreased IL-ß levels in the brain (SMD = -2.02, 95% CI = [-3.22, -0.81], p < 0.005), TNF-α levels (SMD = -0.86, 95% CI = [-1.60, -0.12], p < 0.05), and peripheral vascular IL-1ß levels (SMD = -2.10, 95%CI = [-3.59, -0.61], p < 0.05). In addition, butyrate reduced cerebral infarct volume (MD = -11.29, 95%CI = [-17.03, -5.54], p < 0.05), mNSS score (MD = -2.86, 95%CI = [-4.12, -1.60], p < 0.005), foot fault score (MD = -7.59, 95%CI = [-9.83, -5, 35], p < 0.005), and Morris water maze time (SMD = -2.49, 95%CI = [-4.42, -0.55], p < 0.05). Conclusion: The results of this study indicate that butyrate has a protective effect on cerebral ischaemic stroke in animal models, and the mechanism is related to reducing inflammation and inhibiting apoptosis. It provides an evidence-based basis for the future clinical development of butyrate in the treatment of ischaemic stroke. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, CRD42023482844.

Butyric acid and prospects for creation of new medicines based on its derivatives: a literature review.

The widespread use of antimicrobials causes antibiotic resistance in bacteria. The use of butyric acid and its derivatives is an alternative tactic. This review summarizes the literature on the role of butyric acid in the body and provides further prospects for the clinical use of its derivatives and delivery methods to the animal body. Thus far, there is evidence confirming the vital role of butyric acid in the body and the effectiveness of its derivatives when used as animal medicines and growth stimulants. Butyric acid salts stimulate immunomodulatory activity by reducing microbial colonization of the intestine and suppressing inflammation. Extraintestinal effects occur against the background of hemoglobinopathy, hypercholesterolemia, insulin resistance, and cerebral ischemia. Butyric acid derivatives inhibit histone deacetylase. Aberrant histone deacetylase activity is associated with the development of certain types of cancer in humans. Feed additives containing butyric acid salts or tributyrin are used widely in animal husbandry. They improve the functional status of the intestine and accelerate animal growth and development. On the other hand, high concentrations of butyric acid stimulate the apoptosis of epithelial cells and disrupt the intestinal barrier function. This review highlights the biological activity and the mechanism of action of butyric acid, its salts, and esters, revealing their role in the treatment of various animal and human diseases. This paper also discussed the possibility of using butyric acid and its derivatives as surface modifiers of enterosorbents to obtain new drugs with bifunctional action.

Anti-tumour effect of Huangqin Decoction on colorectal cancer mice through microbial butyrate mediated PI3K/Akt pathway suppression.

Introduction. Huangqin Decoction (HQD), a Chinese herbal formula, is widely used for various diseases, including colorectal cancer (CRC).Hypothesis/Gap Statement. We proposed that microbial butyrate mediated PI3K/Akt pathway suppression might involve the anti-cancer effect of HQD.Aim. This study aimed to evaluate the potential mechanism of HQD against CRC.Methodology. An azoxymethane plus dextran sulphate sodium induced CRC mouse model was used, and the intestinal flora and faecal short-chain fatty acid changes were detected, respectively, after HQD administration with 16S rRNA sequencing and gas chromatography coupled with mass spectrometry. Disease activity index, colon length and levels of inflammatory cytokines were measured to evaluate the effect of HQD on intestinal inflammation. Tumour size, number and histopathology were assessed to reflect the impact of HQD on tumour burden. Apoptosis and PI3K/Akt pathway activity were measured by TUNEL staining and Western-blotting. In vitro, the effects of sodium butyrate (NaB) on the viability of CRC cell lines were detected by the Cell-counting Kit-8. The apoptotic cells were determined by TUNEL staining. Cell migration and invasion were assessed by wound healing assay and Transwell assay, respectively. Western-blotting and immunofluorescent staining were used to test the activity of PI3K/Akt pathway.Results. Animal study showed that HQD could improve the gut dysbiosis, increase the abundance of Clostridium and the level of faecal butyric acid. Then, we found that HQD could attenuate colitis, reduce tumour burden, promote cell apoptosis and suppress PI3K/Akt pathway activity in CRC mice. In vitro experiment revealed that NaB treatment could inhibit cell growth, migration and invasion in CRC cell lines. Additionally, NaB enhanced cellular apoptosis, and reduced phosphorylated PI3K and Akt expressions. Interestingly, addition of 740Y-P, an agonist of PI3K, reversed the NaB effects on CRC cells.Conclusion. Overall, in this study, we revealed that HQD could induce apoptosis through microbial butyrate mediated PI3K/Akt inhibition and perform anti-CRC activity.

Impact of short-chain fatty acid supplementation on gut inflammation and microbiota composition in a murine colitis model.

Short-chain fatty acids (SCFAs) play a pivotal role in maintaining intestinal homeostasis. We aimed to investigate the effects of SCFA supplementation on gut inflammation and microbiota composition in a murine colitis model. Mice were fed with sodium butyrate or a mixture of SCFAs in the drinking water for 2 weeks, followed by 2% dextran sulfate sodium (DSS) for 7 d. After euthanasia, mouse colons were extracted to examine histological findings. Flow cytometry of the mouse colon tissues was performed to assess T cell differentiation. Changes in gut microbiota were assessed by high-throughput sequencing of the mouse feces. There were no significant differences in weight change, colonic length, or histologic inflammation score between the DSS, butyrate, and SCFA mix groups. However, flow cytometry revealed that both the expression of CD4+Foxp3+ regulatory T cells and of IL-17-producing T cells were increased in the butyrate and SCFA mix groups. Microbial compositions of the butyrate and SCFA mix groups were significantly different from those of the control and DSS groups in principal coordinate analysis. Relative abundances of the phyla Verrucomicrobia and Proteobacteria, species Akkermansia muciniphila and Escherichia fergusonii were increased in the butyrate and SCFA mix groups. Genera Roseburia and Lactobacillus showed a negative correlation with the degree of colitis, whereas genera Escherichia and Mucispirillum showed a positive correlation. SCFA supplementation did not result in a significant reduction in colon inflammation, but it promoted both regulatory T cell and IL-17-producing T cell expression, and increased both protective and aggressive gut microbiota.

An altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of postoperative ileus.

BACKGROUND: The aim of this study is to investigate the altered composition of fecal microbiota, organic acids, and the effect of probiotics in the guinea pig model of the postoperative ileus (POI). METHODS: A laparotomy with cecal manipulation was performed to induce POI in guinea pigs. Fecal pellets were collected before the operation (the baseline) and 1, 3, and 5 days after the operation. The extracted fecal DNA was amplified and sequenced using the Illumina MiSeq sequencing system. The same POI procedures were performed after oral pretreatment of the probiotics for 7 days before operation. The effect of the probiotics on the selected taxa and fecal acetate were evaluated, as were the butyrate levels. The colonic transit was assessed by measurement of the fecal pellet output. KEY RESULTS: The communities of the baseline and POI groups indicated significantly distinct composition. The genera Bifidobacterium and Lactobacillus were more abundant in the baseline group compared with the POI groups, and Bacteroides and Blautia were more abundant in the POI groups. Decreased abundances of the species Bifidobacterium bifidum and Bifidobacterium longum after the POI procedure were significantly increased in the probiotics group. The decreased fecal butyrate level after the POI procedure was significantly increased, and colonic transit was significantly improved in the probiotics group. CONCLUSIONS AND INFERENCES: POI induces gut bacterial dysbiosis. Moreover, pretreatment of probiotics before operation restores the beneficial bacterial species, butyrate production, and bowel movement. The modulation of gut microbiota may help the treatment and prevention of POI.

The Suppressive Effect of Butyrate and Bromopyruvate on Inflammatory Cytokine Production and Short Chain Fatty Acid Receptor Expression by Blood Mononuclear Cells in Patients with Behçet's Disease.

BACKGROUND: Controlling inflammation is a therapeutic goal of various autoimmune/autoinflammatory diseases including Behçet's disease (BD). The immunomodulatory effect of metabolites or metabolic analogs such as butyrate and 3-bromopyruvate has been observed in animal disease models. OBJECTIVE: We attempted to evaluate the effect of butyrate and 3-bromopyruvate on the inflammatory cytokine production by peripheral blood mononuclear cells (PBMCs) isolated from patients with mucocutaneous involvement of BD. METHODS: PBMCs isolated from 11 patients with BD and 10 healthy controls were stimulated with lipopolysaccharide in the presence of butyrate or 3-bromopyruvate. Butyrate receptor and cytokine messenger ribonucleic acid (mRNA) expression was analyzed by real-time reverse transcription polymerase chain reaction. Cytokine secretion was assessed by enzyme-linked immunosorbent assay. PBMCs survival was analyzed by flow cytometry. RESULTS: Bromopyruvate or butyrate treatment suppressed inflammatory cytokine production in PBMCs from all our subjects. Bromopyruvate also reduced PBMCs survival while butyrate did not. As the effect of butyrate was slightly greater in BD patients than in healthy controls, we analyzed butyrate receptor expression and found that lipopolysaccharide-induced free fatty acid receptor 2 mRNA level in PBMCs was higher in BD patients than in controls. CONCLUSION: We propose bromopyruvate and butyrate as supplementary therapeutic candidates to control inflammation in patients with BD.

Advances in butyrates and intestinal immune tolerance in children with cow′s milk protein allergy / 国际儿科学杂志

Cow′s milk protein allergy is common in infants, which is an abnormal immune reaction caused by the imbalance of intestinal immune tolerance system.Butyrates, the fermentation product of intestinal anaerobic bacteria, can be used as a histone deacetylase inhibitors and a ligand of G protein-coupled receptors to regulate intestinal innate immunity and adaptive immune function, thereby inducing intestinal immune tolerance in children with cow′s milk protein allergy, which has potential clinical therapeutic value for cow′s milk protein allergy.However, this theory is still only based on the exploration of mechanisms at the cellular and animal levels and has not been applied in the clinic.This article reviews the intestinal immune mechanism of cow′s milk protein allergy, the anabolism of butyrates and the important role of butyrates in intestinal immune tolerance of cow′s milk protein allergy, aiming to lay a theoretical foundation for further clinical application of butyrate-induced intestinal immune tolerance of cow′s milk protein allergy.

Role of histone deacetylase 6 in reduction of intestinal ischemia-reperfusion injury by sodium butyrate in mice / 中华麻醉学杂志

Objective:To evaluate the role of histone deacetylase 6 (HDAC6) in reduction of intestinal ischemia-reperfusion (I/R) injury by sodium butyrate in mice.Methods:Twenty-four SPF healthy adult male C57BL/6 mice, aged 8-10 weeks, weighing 22-25 g, were divided into 4 groups ( n=6 each) by the random number table method: sham operation group (S group), intestinal I/R group (I/R group), intestinal I/R + sodium butyrate group (I/R+ SB group), and intestinal I/R + ITSA-1+ sodium butyrate group (I/R+ I+ SB group). The model of intestinal I/R injury was established by clipping superior mesenteric artery for 45 min followed by 120 min of reperfusion in anesthetized animals.In I/R+ I+ SB group, the HDACs activator ITSA-1 0.5 mg/kg was intraperitoneally injected at 6, 3 and 1 days before ischemia.Sodium butyrate 500 mg/kg was given by intragastric administration every day one week before ischemia in I/R+ SB group and I/R+ I+ SB group, and the equal volume of normal saline was given in S group and I/R group.At 120 min of reperfusion, the mice were sacrificed and their small intestine tissues were obtained.The levels of diamine oxidase (DAO) in serum and intestinal tissues were detected by enzyme-linked immunosorbent assay.The pathological changes of small intestinal tissues were observed with a light microscope, and intestinal damage was assessed and scored according to Chiu.The expression of microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ), P62 and HDAC6 was determined by Western blot.The contents of histone H3 (H3) and acetylated histone H3 (Ac-H3) in small intestinal tissues were determined by enzyme-linked immunosorbent assay. Results:Compared with S group, the Chiu′s score, levels of DAO in serum and small intestinal tissues were significantly increased, the expression of LC3 Ⅱ and HDAC6 was up-regulated, P62 expression was down-regulated, H3 content was increased, and AC-H3 content was decreased in I/R group ( P<0.05). Compared with I/R group, the Chiu′s score, levels of DAO in serum and small intestinal tissues were significantly decreased, the expression of LC3 Ⅱ and HDAC6 was down-regulated, P62 expression was up-regulated, H3 content was decreased, and AC-H3 content was increased in I/R+ SB group ( P<0.05). Compared with I/R+ SB group, the Chiu′s score and levels of DAO in serum and small intestinal tissues were significantly increased, the expression of LC3 Ⅱ and HDAC6 was up-regulated, P62 expression was down-regulated, H3 content was increased, and AC-H3 content was decreased in I/R+ I+ SB group ( P<0.05). Conclusions:Sodium butyrate can alleviate intestinal I/R injury by inhibition of HDAC6 activity in mice, and the mechanism may be related to inhibition of autophagy and promotion of H3 acetylation.

Research Progress on Role and Mechanism of Butyrate in Intestinal Diseases / 胃肠病学

Butyrate is the main product of colonic and cecal microbiota in the fermentation of dietary fiber and some amino acids, which can reduce intestinal inflammation, regulate the balance of intestinal flora, and improve intestinal mucosal barrier. In recent years, a large number of studies at home and abroad have shown that butyrate plays a role in intestinal diseases such as inflammatory bowel disease, irritable bowel syndrome, intestinal ischemia-reperfusion injury, colorectal cancer and short bowel syndrome. This article reviewed the research progress on role and mechanism of butyrate in intestinal diseases.

Role of histone deacetylase in sodium butyrate-induced reduction of intestinal ischemia-reperfusion injury in mice: relationship with oxidative stress and cell apoptosis / 中华麻醉学杂志

Objective:To evaluate the role of histone deacetylase (HDAC) in sodium butyrate-induced reduction of intestinal ischemia-reperfusion (I/R) injury in mice and the relationship with oxidative stress and cell apoptosis.Methods:Twenty-four SPF healthy male C57BL mice, aged 6-8 weeks, weighing 22-25 g, were divided into 4 groups ( n=6 each) according to the random number table method: sham operation group (S group), intestinal I/R group (IR group), intestinal I/R+ sodium butyrate group (IN group) and intestinal I/R+ ITSA-1+ sodium butyrate group (INI group). In IR, IN and INI groups, the superior mesenteric artery was clamped for 45 min, followed by reperfusion for 2 h to prepare the model of intestinal I/R injury, while the superior mesenteric artery was only isolated without ligation in S group.One week before preparation of the model, sodium butyrate 500 mg/kg was intragastrically administered once a day in IN group and INI group, the HDAC activator ITSA-1 0.5 mg/kg was intraperitoneally injected three times a week in INI group, and the equal volume of normal saline was given instead in the other groups.The mice were sacrificed at 2 h of reperfusion and small intestinal tissues were obtained for microscopic examination of the pathological changes which were assessed using Chiu′s score and for determination of the content of MDA (by enzyme-linked immunosorbent assay) and expression of cleaved caspase-3 (by Western blot). Results:Compared with S group, Chiu′s score was significantly increased, and the expression of cleaved caspase-3 was up-regulated in IR, IN and INI groups, the content of MDA in small intestinal tissues was significantly increased in IR and INI groups ( P<0.05). Compared with IR group, Chiu′s score was significantly decreased in IN and INI groups, and the content of MDA was significantly decreased, and the expression of cleaved caspase-3 was down-regulated in IN group ( P<0.05). Compared with IN group, Chiu′s score and content of MDA were significantly increased, and the expression of cleaved caspase-3 was up-regulated in INI group ( P<0.05). Conclusions:HDAC is involved in sodium butyrate-induced reduction of intestinal I/R injury in mice, which is related to the inhibition of oxidative stress and cell apoptosis.

Sodium butyrate inhibits the NF-kappa B signaling pathway and histone deacetylation, and attenuates experimental colitis in an IL-10 independent manner.

Butyrate is a bacterial metabolite of dietary fiber in the colon that has been used to treat inflammatory disease. However, the effect of oral supplementation with butyrate on colitis has not been fully explored. We evaluated the effects of and mechanisms underlying oral supplementation with butyrate on experimental murine colitis. In an in vitro study, we found that LPS induced the secretion of cytokines (i.e., IL-8 in COLO 205; TNF-α, IL-6, IL-12, and IL-10 in RAW 264.7; and TNF-α, IL-6 and IL-12 in peritoneal macrophages obtained from IL-10-deficient [IL-10-/-] mice). Butyrate (100µM and 500µM) inhibited pro-inflammatory cytokine production (i.e., IL-8 in COLO205 and TNF-α, IL-6 and IL-12 in macrophages) but promoted anti-inflammatory cytokine (i.e., IL-10) production in RAW264.7 cells. Butyrate attenuated both the LPS-induced degradation/phosphorylation of IκBα and DNA binding of NF-κB and enhanced histone H3 acetylation. To confirm that butyrate played a protective role in colitis, an acute colitis model was induced using dextran sulfate sodium (DSS) and a chronic colitis model was induced in IL-10-/- mice. The administration of oral butyrate (100mg/kg) significantly improved histological scores in both colitis models, including the IL-10-/- mice. In immunohistochemical staining, IκBα phosphorylation was attenuated, and histone H3 acetylation was reversed in the treated colons of both colitis models. Our results indicate that oral supplementation with butyrate attenuates experimental murine colitis by blocking NF-κB signaling and reverses histone acetylation. These anti-colitic effects of butyrate were IL-10-independent. Butyrate may therefore be a therapeutic agent for colitis.

Role of the Gut Microbiome in Obstructive Sleep Apnea-Induced Hypertension.

Individuals suffering from obstructive sleep apnea (OSA) are at increased risk for systemic hypertension. The importance of a healthy gut microbiota, and detriment of a dysbiotic microbiota, on host physiology is becoming increasingly evident. We tested the hypothesis that gut dysbiosis contributes to hypertension observed with OSA. OSA was modeled in rats by inflating a tracheal balloon during the sleep cycle (10-s inflations, 60 per hour). On normal chow diet, OSA had no effect on blood pressure; however, in rats fed a high-fat diet, blood pressure increased 24 and 29 mm Hg after 7 and 14 days of OSA, respectively (P<0.05 each). Bacterial community characterization was performed on fecal pellets isolated before and after 14 days of OSA in chow and high-fat fed rats. High-fat diet and OSA led to significant alterations of the gut microbiota, including decreases in bacterial taxa known to produce the short chain fatty acid butyrate (P<0.05). Finally, transplant of dysbiotic cecal contents from hypertensive OSA rats on high-fat diet into OSA recipient rats on normal chow diet (shown to be normotensive) resulted in hypertension similar to that of the donor (increased 14 and 32 mm Hg after 7 and 14 days of OSA, respectively; P<0.05). These studies demonstrate a causal relationship between gut dysbiosis and hypertension, and suggest that manipulation of the microbiota may be a viable treatment for OSA-induced, and possibly other forms of, hypertension.

Role of PPARγ/NF-κB signaling pathway in sodium butyrate-induced reduction of intestinal ischemia-reperfusion injury in mice / 中华麻醉学杂志

Objective:To evaluate the role of peroxidase proliferator-activated receptor γ (PPARγ)/nuclear factor kappa B (NF-κB) signaling pathway in sodium butyrate-induced reduction of intestinal ischemia-reperfusion (I/R) injury in mice.Methods:Thirty-two SPF-grade healthy adult male C57BL/6J mice, aged 7-9 weeks, weighing 20-25 g, were divided into 4 groups ( n=8 each) using a random number table method: sham operation group (Sham group), intestinal I/R group (IIR group), sodium butyrate group (NaB group) and PPARγ inhibitor GW9662 group (GW9662 group). The model of intestinal I/R was established by occlusion of superior mesenteric artery for 45 min followed by 2-h reperfusion in anesthetized animals.GW9662 2 mg/kg was intraperitoneally injected at 1 h before ischemia in GW9662 group, and sodium butyrate 500 mg/kg was intraperitoneally injected at 30 min before ischemia in NaB and GW9662 groups.Blood samples were obtained via cardiac puncture at 2 h of reperfusion, and the animals were then sacrificed.The intestinal tissues were removed for determination of diamine oxidase (DAO), tumor necrosis factorα (TNF-α) and interleukins 6 (IL-6) concentrations in serum (by enzyme-linked immunosorbent assay) and the expression of PPAR and NF-κB p65 (by Western blot). The damage to intestinal mucous membrane was assessed and scored according to Chiu. Results:Compared with group Sham, the Chiu′s score was significantly increased, levels of DAO, TNF-α and IL-6 in serum and intestinal tissues were increased, expression of PPARγ was down-regulated, and expression of NF-κB p65 was up-regulated in group IIR ( P<0.05). Compared with group IIR, the Chiu′s score, levels of DAO, TNF-α and IL-6 in serum and intestinal tissues were decreased, and expression of PPARγ was up-regulated in group NaB, and expression of NF-κB p65 was up-regulated in NaB and GW9662 groups ( P<0.05). Compared with group NaB, the Chiu′s score, levels of DAO, TNF-α and IL-6 in serum and intestinal tissues were increased, and expression of PPARγ was down-regulated, and expression of NF-κB p65 was up-regulated in group GW9662 ( P<0.05). Conclusion:The mechanism by which sodium butyrate reduces intestinal I/R injury may be related to activating PPARγ/NF-κB signaling pathway and inhibiting inflammatory responses in mice.

Gut dysbiosis is linked to hypertension.

Emerging evidence suggests that gut microbiota is critical in the maintenance of physiological homeostasis. This study was designed to test the hypothesis that dysbiosis in gut microbiota is associated with hypertension because genetic, environmental, and dietary factors profoundly influence both gut microbiota and blood pressure. Bacterial DNA from fecal samples of 2 rat models of hypertension and a small cohort of patients was used for bacterial genomic analysis. We observed a significant decrease in microbial richness, diversity, and evenness in the spontaneously hypertensive rat, in addition to an increased Firmicutes/Bacteroidetes ratio. These changes were accompanied by decreases in acetate- and butyrate-producing bacteria. In addition, the microbiota of a small cohort of human hypertensive patients was found to follow a similar dysbiotic pattern, as it was less rich and diverse than that of control subjects. Similar changes in gut microbiota were observed in the chronic angiotensin II infusion rat model, most notably decreased microbial richness and an increased Firmicutes/Bacteroidetes ratio. In this model, we evaluated the efficacy of oral minocycline in restoring gut microbiota. In addition to attenuating high blood pressure, minocycline was able to rebalance the dysbiotic hypertension gut microbiota by reducing the Firmicutes/Bacteroidetes ratio. These observations demonstrate that high blood pressure is associated with gut microbiota dysbiosis, both in animal and human hypertension. They suggest that dietary intervention to correct gut microbiota could be an innovative nutritional therapeutic strategy for hypertension.

Advances in Study on Role of Butyrate in Prevention and Treatment of Non-alcoholic Fatty Liver Disease / 胃肠病学

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, and its incidence is increasing year by year. The mechanism of NAFLD is not fully understood, and it lacks effective prevention and treatment. Recent studies have found that butyrate, as a short-chain fatty acids (SCFAs), plays an important role in gene regulation, immunoregulation, inhibition of tumor, regulation of intestinal mucosal barrier, and reduction of oxidative stress. Several studies have shown that butyrate could alleviate NAFLD. This article reviewed the mechanism of butyrate in the pathogenesis of NAFLD and its application in the treatment of NAFLD, so as to provide a new idea for the prevention and treatment of NAFLD.