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PubMed1996

The role of glutamine, short-chain fatty acids, and nucleotides in intestinal adaptation to gastrointestinal disease.

Important first steps have been taken towards establishing how some nutrients interact with genes and affect intestinal adaptation. These mechanisms may be typical of how other nutrients influence cell function and turnover and help to maintain intestinal integrity. The dietary effects of nucleotides on intestinal cell mucosa act at the gene transcription level. The dietary effects of nucleotides on immune suppression also may act through similar mechanisms. The effects of the other trophic agents may interact at this level or at other levels. Scientific interest in how the various tropic factors work to maintain and repair the gastrointestinal tract is manifested by a growing body of research that demonstrates potential mechanisms for nutrient-gene interaction and how much interactions affect intestinal development and turnover. It seems clear that intestinal gene transcription and the activity of transcription factors are at least sometimes directly related to nutrition. The techniques of molecular biology now permit the exploration and explanation of how dietary factors, such as glutamine, SCFAs, and nucleotides, affect normal and pathologic intestinal mucosal development, function, adaptation, and repair.

Adaptation, Physiological↗

PubMed2000

Short-chain fatty acid enemas stimulate plasminogen activator inhibitor-1 after abdominal aortic graft surgery: a double-blinded, placebo-controlled study.

Colonic ischaemia may complicate aortic graft surgery with high mortality from associated colonic necrosis. Loss of the mucosal barrier function due to ischaemia may promote translocation of endotoxins with secondary systemic disseminated coagulation leading to multiple organ failure. Short-chain fatty acids (SCFAs) stimulate the microcirculation in the human rectum. The aim of this study was to investigate whether SCFA enemas influence systemic endotoxinaemia and fibrinolytic activity during and after elective aortic graft surgery for arteriosclerosis. Thirty-two patients were randomized to SCFA or placebo enemas twice daily from the day before surgery to 7 days after. Blood samples for endotoxin, plasminogen activator inhibitor-1 (PAI-1) activity, tissue-type plasminogen activator (t-PA) antigen, and cross-linked fibrin degradation products (XL-FDP) were drawn before, during, and 7 days after surgery. Four patients, two in each treatment group, developed postoperative endotoxinaemia. PAI-1 was significantly higher on days 2 and 4 in SCFA-treated patients, whereas t-PA was comparable Petween the groups. During the postoperative course, a progressive and near-identical XL-FDP increase was found in the two groups. In elective aortic graft surgery for arteriosclerosis, SCFA enemas likely stimulate systemic PAI-1 activity by promoting colonic tissue reperfusion following aortic unclamping. Endotoxinaemia and fibrinolytic shutdown are uncommon findings.

Aged↗

PubMed1999

Safety evaluation of phytosterol esters. Part 5. Faecal short-chain fatty acid and microflora content, faecal bacterial enzyme activity and serum female sex hormones in healthy normolipidaemic volunteers consuming a controlled diet either with or without a phytosterol ester-enriched margarine.

A study was conducted in 12 healthy males and 12 healthy females (mean age 36 years, mean body mass index 24 kg/m2), to determine the effect of a margarine enriched with phytosterol esters on faecal short-chain fatty acids (SCFAs) and faecal bacterial enzyme activities, viable faecal microflora count, female sex hormones and serum cholesterol concentrations. The study design was a two-period, parallel dosing, randomized, placebo-controlled dietary study. Under controlled dietary conditions, participants consumed 40 g of the control margarine for 21 and 28 consecutive days for males and females, respectively. This was followed immediately by the second part of the study where subjects were equally and randomly allocated to consume daily 40 g of either the control or the test margarine, containing 8.6 g vegetable oil phytosterols (a mixture of beta-sitosterol, campesterol and stigmasterol), also for 21 or 28 days. All females were shown to have a regular menstrual cycle and were on an established method of contraception not involving oral contraceptives. When compared with the control group values, the test group showed a significant reduction in serum total and LDL cholesterol concentrations of 18 and 23% (P < 0.001; P < 0.001) respectively, in faecal lactic acid concentration (P = 0.039) and in serum progesterone levels (P = 0.021). There were no other significant treatment effects. Within each group a number of significant changes occurred compared to baseline. In the test group, faecal lactic acid concentration and the ratio of acetic acid:total SCFA; and the ratio of butyric acid:total SCFA, in the control group were both significantly reduced (P = 0.016). Compared to baseline, azo-reductase activity was significantly reduced in the control group (P = 0.047). Total faecal aerobes (P = 0.028), lactobacilli (P = 0.003) and staphylococci (P = 0.025) content was also significantly reduced in the control group, while in the test group only lactobacilli content was reduced (P = 0.019). Of the significant findings reported in this study, none was considered to be of biological importance except the beneficial reduction in serum total and LDL-cholesterol concentrations. The daily consumption of a margarine enriched with 8.6 g vegetable oil phytosterols did not affect the bacterial profile or the metabolic activities of the gut microflora, nor did it result in biologically relevant effects on serum female sex hormone levels. The margarine enriched with the vegetable oil phytosterols was well tolerated by both male and female volunteers.

Bacteria↗

PubMed1997

Transepithelial SCFA gradients regulate polarized Na/H exchangers and pH microdomains in colonic epithelia.

Short chain fatty acids (SCFAs) stimulate electroneutral sodium absorption by activation of apical Na/H exchange in colonocytes. It is often assumed that activation of Na/H exchange is via an intracellular acidification caused by SCFA uptake. These lecture notes review shortcomings in this model of SCFA-stimulated sodium absorption, revealed by recent reports in the literature. This is supplemented by information generated in our laboratory using both a tissue culture model of colonocytes (HT29-C1 cells) and a native tissue preparation (mouse distal colonic mucosa). In both preparations, evidence suggests that physiologic SCFA gradients may generate pH heterogeneity in aqueous microdomains near the plasma membrane of colonocytes. Finally, direct observation of such extracellular microdomains with confocal microscopy is used to support a new model, in which pH microdomains play an important role in regulating both SCFA fluxes and sodium absorption.

Animals↗

PubMed1997

Transepithelial SCFA fluxes link intracellular and extracellular pH regulation of mouse colonocytes.

We have studied pH regulation in both intracellular and extracellular compartments of mouse colonic crypts, using distal colonic mucosa with intact epithelial architecture. In this work, we question how transepithelial SCFA gradients affect intracellular pH (pHi) and examine interactions between extracellular pH (pHo) and pHi regulation in crypts of distal colonic epithelium from mouse. We studied pH regulation in three adjacent compartments of distal colonic epithelium (crypt lumen, crypt epithelial cell cytosol, and lamina propria) with SNARF-1 (a pH sensitive fluorescent dye), digital imaging microscopy (for pHi), and confocal microscopy (for pHo). Combining results from the three compartments allows us to find how pHi and pHo are regulated and related under the influence of physiological transepithelial SCFA gradients, and develop a better understanding of pH regulation mechanisms in colonic crypts. Results suggest a complex interdependency between SCFA fluxes and pHo values, which can directly affect how strongly SCFAs acidify colonocytes.

Animals↗

PubMed1999

Headspace solid-phase microextraction with 1-pyrenyldiazomethane in-fibre derivatisation for analysis of faecal short-chain fatty acids.

Short chain fatty acids (SFCAs) are nutritionally important products of colonic bacteria. Their analysis in faeces is problematic. We report a headspace solid-phase microextraction procedure in which faecal SCFAs are derivatised on the fibre in-situ with 1-pyrenyldiazomethane. With this method sharp, well-resolved chromatographic peaks were obtained with no interferences. Inclusion of deuterated analogues enabled accurate quantification. Good linearity, recoveries and precision were achieved. Differences observed between the SCFA profiles of normal subjects and patients with cystic fibrosis indicate the potential of this new technique for clinical studies. 2-Methylbutyric acid was found in all faecal samples. Few have reported this before.

Case-Control Studies↗

PubMed2005

An oral supplement enriched with fish oil, soluble fiber, and antioxidants for corticosteroid sparing in ulcerative colitis: a randomized, controlled trial.

BACKGROUND & AIMS: N-3 fatty acids from fish oil, antioxidants, and short-chain fatty acids (SCFAs) produced during the fermentation of soluble fiber may attenuate inflammation associated with ulcerative colitis (UC). We assessed the efficacy of a nutritionally balanced oral supplement enriched with fish oil, fructooligosaccharides, gum arabic, vitamin E, vitamin C, and selenium on disease activity and medication use in adults with mild to moderate UC. METHODS: A total of 121 patients with UC and a disease activity index (DAI) from 3-9 on a 12-point scale were block randomized for extent of disease and smoking status. In addition to their usual diet, patients consumed 18 oz of the oral supplement or a carbohydrate-based placebo formula each day for 6 months. Clinical and histologic responses were assessed at 3 and 6 months or at the final visit. A change in average prednisone use between groups was tested by using a linear mixed-effects model. RESULTS: Eighty-six patients completed the study. Baseline characteristics were not different between groups except for a higher total DAI score in the oral supplement group (7.3 +/- 1.3; n = 36) compared with the placebo group (6.2 +/- 2.0; n = 50) ( P < .05). Both groups showed significant and similar degree of improvement at 6 months in DAI (-2.5 for oral supplement and -2.8 for placebo) and histologic index (-1.9 for oral supplement vs. -2.0 for placebo). Both intent-to-treat and completed patients given oral supplement had a significantly greater rate of decrease in the dose of prednisone required to control clinical symptoms over 6 months as compared with the placebo group ( P < .001). CONCLUSIONS: The improvement in clinical response combined with a decreased requirement for corticosteroids suggest that this enriched oral supplement can be a useful adjuvant therapy in patients with UC.

Administration, Oral↗

PubMed2005

Dietary fibers from mushroom sclerotia: 3. In vitro fermentability using human fecal microflora.

The in vitro fermentability of three novel dietary fibers (DFs) prepared from mushroom sclerotia, namely, Pleurotus tuber-regium, Polyporous rhinocerus, and Wolfiporia cocos, was investigated and compared with that of the cellulose control. All DF samples (0.5 g each) were fermented in vitro with a human fecal homogenate (10 mL) in a batch system (total volume, 50 mL) under strictly anaerobic conditions (using oxygen reducing enzyme and under argon atmosphere) at 37 degrees C for 24 h. All three novel sclerotial DFs exhibited notably higher dry matter disappearance (P. tuber-regium, 8.56%; P. rhinocerus, 13.5%; and W. cocos, 53.4%) and organic matter disappearance (P. tuber-regium, 9.82%; P. rhinocerus, 14.6%; and W. cocos, 57.4%) when compared with those of the cellulose control. Nevertheless, only the W. cocos DF was remarkably degraded to produce considerable amounts of total short chain fatty acids (SCFAs) (5.23 mmol/g DF on organic matter basis, with a relatively higher molar ratio of propionate) that lowered the pH of its nonfermented residue to a slightly acidic level (5.89). Variations on the in vitro fermentability among the three sclerotial DFs might mainly be attributed to their different amounts of interwoven hyphae present (different amounts of enzyme inaccessible cell wall components) as well as the possible different structural arrangement (linkage and degree of branching) of their beta-glucans.

Basidiomycota↗

PubMed1999

Influence of feces from patients with ulcerative colitis on butyrate oxidation in rat colonocytes.

An impaired oxidation of butyrate has been suggested as a causative factor of ulcerative colitis and, moreover, agents present in colonic luminal contents impair butyrate oxidation in both rat and human colonocytes. To evaluate the overall effect of feces on the production of CO2 and ketone bodies from butyrate oxidation in rat colonocytes, fecal homogenates from 10 healthy subjects and 10 patients with quiescent and 10 patients with active ulcerative colitis were sterile filtrated and added to rat colonocytes incubated with 2, 4, and 10 mmol/liter of stock butyrate, respectively. Addition of fecal filtrate from healthy subjects and patients with quiescent and active ulcerative colitis to colonocytes incubated with 2, 4, and 10 mmol/liter of stock butyrate, respectively, tended to decrease the production of CO2 from butyrate oxidation, whereas ketogenesis was unaffected. The decrease in CO2 production was not explained by the simultaneous addition of fecal short-chain fatty acids (SCFAs). However, a difference in the ability to decrease CO2 production was not found between filtrates from healthy subjects and patients with quiescent and active ulcerative colitis. In conclusion, feces from healthy subjects and patients with quiescent and active ulcerative colitis contain inhibitor(s) of the production of CO2 from butyrate oxidation in colonocytes. However, a specific inhibitory effect of feces from patients with ulcerative colitis on the production of CO2 could not be identified.

Adult↗

PubMed2025

Nutritional modulation of host physiology, behavior, and gut microbiome in the captive rodent Octodon degus.

Diet is a key determinant of health by affecting nutrient metabolism, energy balance, body weight regulation, and mental health. The gut-brain axis is a critical pathway through which dietary factors influence cognitive function and behavior via microbial metabolites. While this relationship has been extensively studied in traditional laboratory models, diet-microbiome-cognition interactions remain largely unexplored in Octodon degus, an emerging model for aging, neurodegeneration, and cognitive research. Here, we compared two widely used rodent diets-LabDiet and Champion-to evaluate their effects on digestive efficiency, behavior, and gut microbiome composition. We also examined the relationships between these variables using piecewise structural equation modeling (pSEM). Our results indicated that LabDiet-fed degus exhibited enhanced nutrient absorption, higher fecal acetic acid levels, and a higher abundance of Actinobacteria (particularly Bifidobacterium), likely driven by its vitamin C supplementation. These animals also showed improved working memory and social motivation, but they displayed increased anxiety-like behavior. In contrast, Champion-fed degus, which consumed a more fiber-diverse, plant-based diet, showed lower anxiety traits and significantly greater gut microbial richness, with higher abundance of Bacteroidota and Tenericutes. Innate behaviors, such as burrowing and nesting, remained unaffected by the diet. SEM analysis revealed that diet explained most of the variance in microbial activity and identified a positive association between acetic acid levels and cognitive performance. This emphasizes a strong relationship among diet, microbiome, and brain function. Overall, our results suggest that dietary composition is a key factor influencing experimental outcomes in degus, with important implications for physiology, cognition, and microbial ecology. Standardizing dietary inputs is essential to ensure reproducibility in behavioral and biomedical studies using this model. Additionally, our results reinforce the microbiome's role as a mediator of diet-driven brain function via SCFAs, underscoring degus as a powerful system for investigating diet-microbiome-neurobehavioral interactions relevant to aging and mental health.

Animals↗

PubMed1999

The effect of sucrose or starch-based diet on short-chain fatty acids and faecal microflora in rats.

An investigation was carried out to determine whether variations of dietary carbohydrates could modify the colonic flora in rats. Sprague-Dawley rats were fed with two equicaloric diets based on the AIN-76 diet (American Institute of Nutrition 1977) but differing from that diet in content of carbohydrates, i.e. high sucrose (64%) of high corn starch (64%). Feeding was continued for 9 months ad libitum and no variation in weight gain was recorded among the different diets. A prevalence of aerobes, and a significant reduction in the ratio anaerobes/aerobes in the faeces of rats on the high starch diet compared with the high sucrose diet, was observed. The anaerobe genera identified included Actinomyces, Bacteroides, Bifidobacterium, Clostridium, Eubacterium, Lactobacillus and Propionibacterium. Bacteroides was the most prevalent genus in both dietary groups (51.2 and 29.5% in the faeces of rats fed the sucrose and starch diets, respectively). In contrast, clostridia were prevalent in the starch-fed group (23.8%) and less so in the sucrose diet (11.5%), as propionibacteria were prevalent in faeces of rats fed the starch diet (15.5%), and low in the sucrose diet (3.9%). The remaining genera were scarce in faeces from rats on either diet. Total short-chain fatty acids (SCFA) were significantly higher in the faeces of animals fed the starch diet compared with those fed the sucrose diet. The relative concentrations of acetic, propionic and butyric acids were not significantly different between the two dietary groups. In conclusion, high starch diet can markedly modify the composition of faecal flora and alter considerably the faecal concentration of SCFAs, compound which might have a health-promoting effect.

Animal Nutritional Physiological Phenomena↗

PubMed2002

Biochemical intestinal parameters in pigs reared outdoors and indoors, and in germ-free pigs.

Intestinal microbial functions reflect cross-talk between a host and its flora, and external factors may influence these functions. The aim of this investigation was to follow the development of six biochemical microbial-related functions of piglets, raised outdoors (OPs) or indoors (IPs), from birth to slaughter age. The following parameters (microflora-associated characteristic; MAC) were consecutively measured at five different ages: production of short-chain fatty acids (SCFA), conversion of cholesterol to coprostanol and of bilirubin to urobilinogens, inactivation of trypsin, degradation of beta-aspartylglycine and of mucin. Additionally, four parameters (production of SCFA. conversion of cholesterol to coprostanol, inactivation of trypsin, degradation of beta-aspartylglycine) were investigated in faecal samples from germ-free minipigs. The differences in MAC patterns between OPs and IPs were most pronounced at 20 days of age. Differences were found in the total amount of SCFAs, proportions of the acetic, propionic and butyric acids, conversion of bilirubin to urobilinogens, degradation of faecal tryptic activity and degradation of mucin. The values found in the minipigs were within the range of a germ-free animal characteristic (GAC) pattern. Our results show that environmental factors influence the development of some intestinal microbial functions in pigs.

Animal Husbandry↗

PubMed1989

Incidence of the circadian rhythm of the excretion pattern on acetate absorption and metabolism in the rabbit hind-gut.

Acetate absorption in the hind-gut of anaesthetized rabbits was evaluated by measuring variations in the concentration of acetate in caecocolonic loops and in arterial and venous plasma. In vivo metabolism in gut and liver tissues was studied using [1-14C]acetate. Interrelations between acetate absorption and metabolism and both phases of the excretory cycle of the rabbit were examined. The disappearance rate from the caecocolonic loop was quantitatively significant. The gut tissue metabolized acetate, and the intensity of utilization varied with the segment studied; the distal position of the large intestine showed by far the highest uptake of short-chain fatty acids (SCFAs). In addition, acetate absorption, like its metabolism in the hind-gut and liver tissues, differed in intensity according to the phase of the excretory cycle, i.e., both mechanisms were enhanced during hard faeces production. Radioactivity was found in free amino acids, organic acids and sugars. Irrespective of the location in the gut and the excretion pattern, acetate was rapidly converted into glutamate and aspartate; these nutrients were subsequently diverted towards either oxidative metabolism or biosyntheses (non essential free amino acids, proteins).

Acetates↗

PubMed2000

The dietary combination of germinated barley foodstuff plus Clostridium butyricum suppresses the dextran sulfate sodium-induced experimental colitis in rats.

BACKGROUND: Recent studies have suggested that dietary fiber exerts a therapeutic effect on IBD patients. The aim of this study was to evaluate the effects of a dietary combination of germinated barley foodstuff (GBF), derived from the aleurone and scutellum fraction of germinated barley, plus Clostridium butyricum against dextran sulfate sodium (DSS)-induced experimental colitis in rats. METHODS: Sprague-Dawley rats were fed a 3% DSS diet containing GBF only, GBF plus C. butyricum, cellulose only (control) or cellulose plus C. butyricum for 8 days. The mucosal damage (macroscopic and microscopic inflammation) and fecal short-chain fatty acid (SCFA) levels were then determined. RESULTS: The combination of GBF plus C. butyricum most effectively prevented bloody diarrhea and mucosal damage. The GBF-only diet also showed some preventive effects. With respect to fecal SCFAs, the combination of GBF plus C. butyricum most effectively increased the fecal SCFA level. CONCLUSION: The dietary combination of GBF plus C. butyricum most effectively suppressed DSS-induced experimental colitis in rats. These effects may be closely associated with its high activity to increase SCFA levels in the gut lumen. The potential clinical efficacy of GBF in IBD patients is also discussed.

Animals↗

PubMed2005

Effects of metronidazole and oligofructose on faecal concentrations of sulphate-reducing bacteria and their activity in human volunteers.

OBJECTIVE: Sulphate-reducing bacteria (SRB) have been implicated in the aetiology of ulcerative colitis. Sulphide produced from reduction of sulphate by SRB is highly toxic to colonocytes and can impair their metabolic function. The aim of this study was to investigate the modulation of the colonic bacterial flora using metronidazole and the prebiotic oligofructose on the concentration and activity of SRB. MATERIAL AND METHODS: Healthy volunteers were randomly allocated to take metronidazole (5 days), oligofructose (12 days) or both metronidazole (5 days) and oligofructose (12 days). At days 0, 5, 12 and 19, stool samples were cultured, and their pH measured; concentrations of sulphate, hydrogen sulphide, short-chain fatty acids (SCFAs) were measured and the sulphate reduction rates (SRRs) determined. RESULTS: In SRB-positive volunteers (n=16) faecal SRB concentrations fell with metronidazole (95% CI, 2.19, 3.36 p<0.0001) even when combined with oligofructose (95% CI 2.32, 4.01 p<0.0001). Faecal anaerobe concentrations fell with metronidazole and bifidobacterial concentrations rose with oligofructose irrespective of SRB status. Faecal SRRs fell with metronidazole irrespective of the presence of faecal SRB (95% CI 29.0, 56.1 p<0.0001). No changes in faecal sulphate concentrations were seen. Faecal hydrogen sulphide concentrations fell with oligofructose in SRB-positive volunteers (95% CI 0.14, 0.53 p=0.002). Faecal SCFA concentrations fell with metronidazole (-103.7, -19.6, p=0.007) and rose with oligofructose (9.9, 83.1 p=0.016). CONCLUSIONS: The study shows that metronidazole, but not oligofructose, reduced the concentration and activity of faecal SRB. This reduction had no impact on faecal concentrations of sulphate and hydrogen sulphide, suggesting that other methods of hydrogen sulphide production are more important. Oligofructose causes a reduction in faecal hydrogen sulphide, and an increase in SCFA concentrations may thus have a therapeutic role in patients with ulcerative colitis.

Adult↗

PubMed1997

Diet and carcinogen alter luminal butyrate concentration and intracellular pH in isolated rat colonocytes.

A 2 x 2 factorial experiment was conducted to examine the effects of two different dietary fibers and carcinogen treatment on colonic luminal short-chain fatty acid (SCFA) concentrations and intracellular pH (pHi) in rats. Twenty-four male Sprague-Dawley rats were divided into four groups, injected with a carcinogen [azoxymethane (AOM)] or normal saline (Sal), and fed one of two diets differing only in the type of dietary fiber [cellulose (Cell) or pectin (Pect)]. After 38 weeks of consuming these diets, the rats were euthanized, luminal contents were collected for analysis of SCFA concentrations, and colonocytes were isolated from the proximal and distal colon for subsequent determination of pHi. Changes in pHi after the addition of exogenous sodium butyrate to the culture medium were also tested. The highest concentrations of SCFAs were produced by the control rats (saline injected) consuming the pectin diet. Luminal butyrate concentrations were reduced in three of four colonic segments of carcinogen-injected groups [proximal and distal cellulose (Prox Cell and Dist Cell) and distal pectin (Dist Pect)] compared with saline controls. The pHi was consistently higher in colonocytes isolated from carcinogen-injected rats (Prox Cell/AOM = 6.95 vs. Prox Cell/Sal = 6.65, Prox Pect/AOM = 6.75 vs. Prox Pect/Sal = 6.65, Dist Cell/AOM = 6.94 vs. Dist Cell/AOM = 6.85, Dist Pect/AOM = 6.92 vs. Dist Pect/Sal = 6.79) than in cells from saline-injected rats. Furthermore, in the majority of rats, pHi was lower in the proximal than in the distal colon. Addition of butyrate to cultured colonocytes consistently lowered pHi, but the effect was more pronounced in the carcinogen-injected animals. These data identify changes that occur intraluminally and intracellularly in colons of rats injected with AOM and suggest that, during tumorigenesis, alterations in butyrate production and basic colonocyte physiology may play an important role in the process.

Animals↗

PubMed2026

The gut microbiota-obesity axis in the pathogenesis and prognosis of breast cancer.

BACKGROUND: Breast cancer (BC) remains a major global health concern, accounting for 11.7% of all cancer cases and ranking as the second leading cause of female cancer-related deaths worldwide. Increasing evidence highlights the interplay between gut microbiota (GM) dysbiosis and obesity-associated metabolic dysfunction in BC progression. This review aims to elucidate the role of GM in obese patients with BC. METHODS: A systematic literature search was conducted in PubMed and Web of Science databases for publications from July 2015 to January 2025. Search terms combined BC, GM, obesity, dysbiosis, immunity, and microbiome. Article selection prioritized studies investigating microbial alterations in BC patients, mechanistic links between obesity and cancer progression, and GM-targeted interventions. Both original studies and authoritative reviews were included, supplemented by manual reference screening. DISCUSSION: Obesity may trigger systemic inflammation, altered adipokine secretion, and disrupted steroid hormone metabolism via gut-derived β-glucuronidase activity, thereby exacerbating BC occurrence and recurrence. GM dysbiosis-driven metabolites such as branched-chain amino acids (BCAAs) and short-chain fatty acids (SCFAs) can activate oncogenic signaling pathways and immunosuppressive myeloid-derived suppressor cells (MDSCs), fostering tumor immune evasion. Conversely, dietary interventions, probiotics, and fecal microbiota transplantation (FMT) can alleviate dysbiosis, strengthen gut barriers, and restore anti-tumor immunity, improving chemotherapy response and reducing recurrence. However, challenges persist in deciphering BC subtype-related microbial signatures and optimizing microbiota-targeted therapies. CONCLUSION: Future longitudinal studies are needed to clarify causal relationships, validate microbial biomarkers, and translate preclinical findings into clinical applications. Addressing the gut-breast axis may offer transformative potential for precision oncology in obesity-driven BC.

Humans↗

PubMed1987

Fecal short-chain fatty acid (SCFA) analysis by capillary gas-liquid chromatography.

A new method is described for short-chain fatty acid (SCFA) analysis in stool samples. After sample purification by acid vacuum transfer and concentration by alkaline freeze-drying, SCFAs were measured by gas-liquid chromatography using a capillary column. Peak resolution and reproducibility were superior to SCFA analysis on a conventional glass column. With this new technique SCFA were quantitated in stool samples of six healthy volunteers on a basal diet with and without a fermentable dietary fiber preparation; fiber had no effect on fecal SCFA concentration. In two patients with a short-bowel syndrome, SCFA could be demonstrated in stool samples, indicating active fermentation.

Acetates↗