Low Bile Acid Research Articles

Accumulation of altered serum bile acids predicts liver injury after portoenterostomy in biliary atresia.

Little is known on the mechanism of liver injury mediated by bile acids following Kasai portoenterostomy (KPE) in biliary atresia (BA). We sought to quantify individual serum bile acids, 7-alpha-hydroxy-4-cholesten-3-one (C4), and fibroblast growth factor 19 (FGF19) after KPE and to evaluate their prognostic utility and transcriptomic regulation. Serum (n=244) and liver specimens (n=105) prospectively obtained from BA patients (n=54) after KPE were included. Bile acids were analyzed using mass spectrometry, gene expression with quantitative PCR, and histopathology using a neural network model. Following KPE, serum bile acids correlated positively with biochemical liver injury, pediatric end-stage liver disease score, liver stiffness, histological ductular reaction, and liver fibrosis. Bile acids were higher among patients who developed portal hypertension (79.6 vs. 11.9 μmol/l, p<0.0001), esophageal varices (91.6 vs. 16.2 μmol/l, p<0.0001), or required liver transplantation (LT, 115.3 vs. 22.0 μmol/l, p<0.0001) during follow up; bile acids predicted these outcomes in time-dependent regression models. Accumulation of conjugated bile acids, cholic acid, and taurine conjugates predicted LT risk while associating with histological liver injury. Serum C4 (0.04 vs. 0.00 μmol/l, p=0.04) and liver CYP7A1 were higher in native liver survivors than in LT patients (fold-change 16.9 vs. 7.0, p=0.02). Primary bile acids correlated negatively with C4 (R=-0.38, p<0.001) and CYP7A1 (R=-0.49, p=0.01). Unlike in native liver survivors (R=-0.19, p=0.66), serum FGF19 correlated with liver FGF19 (R=0.59, p=0.04) without an inverse association with serum primary bile acids in LT patients (R=0.26, p=0.08). Accumulation and altered composition of serum bile acids predicted progressive liver disease and poorer transplant-free survival following KPE. Poor prognosis was associated with low bile acid synthesis and aberrantly increased liver FGF19. Biliary atresia (BA), a fibro-obliterating biliary disease of infants, remains the most common indication for pediatric liver transplantation caused by rapid progression of liver injury. To identify predictive biomarkers of disease progression and to elucidate the pathophysiology of BA liver injury, we profiled serum bile acids and studied their liver metabolism after Kasai portoenterostomy. Accumulation and altered composition of circulating bile acids predicted progression of liver disease and need for liver transplantation. Patients with poor prognosis showed low bile acid synthesis and abnormal liver expression of fibroblast growth factor 19.

Levels of Bile Acid Metabolism Are Associated With Alterations of Gut Microbes in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is viewed as a metabolism associated disease, and bile acid metabolism is reported to occupy a significant role in the progression of HCC. However, little is known about the association between gut microbes and bile acid metabolism in HCC. Our study was designed to clarify the role of bile acid metabolism and microbiome in the progression of HCC. We investigated the relationship between bile acid metabolism and prognosis and immune cells by mining GSE14520. We studied the microbial profiles and metabolic alterations between the low bile acid group and high bile acid group using 16S rRNA sequencing and metabolomics. HCC patients in the high bile acid metabolism group showed better survival outcome compared with those in the low bile acid metabolism. Immune analysis displayed the close correlation between low bile acid metabolism and infiltration of CD4 + T cells, and the close relationship between high bile acid metabolism and infiltration of CD8 + T cells, macrophage cells in HCC. 16S rRNA sequencing results demonstrated that Blautia, Ruminococcus_gnavus_group, Erysipelotrichaceae_UCG-003 were mostly enriched in the low bile acid group. Metabolomics of the 109 fecal samples showed that the most enriched metabolites in the low total bile acid group were dihydrocytochalasin B, cucurbic acid and 27-Norcholestanehexol. Finally, KEGG enrichment analysis identified secondary bile acid biosynthesis and endocrine resistance as the most significant metabolic pathways. High bile acid metabolism was associated with more infiltration of CD8 + T cells, macrophage cells, and better prognosis in HCC. Levels of bile acid were significantly associated with altered gut microbes and metabolites in HCC. Further research related to gut microbes and bile acid metabolism may provide a novel insight into the pathogenesis and therapeutic strategy of HCC.

Elevated plasma bile acids coincide with cardiac stress and inflammation in young Cyp2c70-/- mice.

High plasma bile acids (BAs), for instance due to intrahepatic cholestasis of pregnancy or neonatal cholestasis, are associated with cardiac abnormalities. Here, we exploited the variability in plasma BA levels in Cyp2c70-/- mice with a human-like BA composition to investigate the acute effects of elevated circulating BAs on the heart. RNA sequencing was performed on hearts of 3-week-old Cyp2c70-/- mice lacking mouse-specific BA species that show features of neonatal cholestasis. Cardiac transcriptomes were compared between wild-type pups, Cyp2c70-/- pups with low or high plasma BAs, and Cyp2c70-/- pups from dams that were perinatally treated with ursodeoxycholic acid (UDCA). We identified 1355 genes that were differentially expressed in hearts of Cyp2c70-/- mice with high versus low plasma BAs with enrichment of inflammatory processes. Strikingly, expression of 1053 (78%) of those genes was normalized in hearts of pups of UDCA-treated dams. Moreover, 645 cardiac genes strongly correlated to plasma BAs, of which 172 genes were associated with cardiovascular disease. Elevated plasma BAs alter gene expression profiles of hearts of mice with a human-like BA profile, revealing cardiac stress and inflammation. Our findings support the notion that high plasma BAs induce cardiac complications in early life. Cyp2c70-/- mice with a human-like bile acid composition show features of neonatal cholestasis but the extrahepatic consequences hereof have so far hardly been addressed Elevated plasma bile acids in Cyp2c70-/- pups coincide with cardiac stress and inflammation Perinatal treatment with UDCA prevents dysregulated cardiac gene expression patterns in Cyp2c70-/- pups.

Characterization of individual bile acids in vivo utilizing a novel low bile acid mouse model.

Bile acids (BAs) are signaling molecules synthesized in the liver initially by CYP7A1 and CYP27A1 in the classical and alternative pathways, respectively. BAs are essential for cholesterol clearance, intestinal absorption of lipids, and endogenous modulators of farnesoid x receptor (FXR). FXR is critical in maintaining BA homeostasis and gut-liver crosstalk. Complex reactions in vivo and the lack of suitable animal models impede our understanding of the functions of individual BAs. In this study, we characterized the in vivo effects of three-day feeding of cholic acid (CA), deoxycholic acid (DCA), or ursodeoxycholic acid (UDCA) at physiological/non-hepatotoxic concentrations in a novel low-BA mouse model (Cyp7a1-/-/Cyp27a1-/-, DKO). Liver injury, BA levels and composition and BA signaling by the FXR-fibroblast growth factor 15 (FGF15) axis were determined. Overall, higher basal inflammation and altered lipid metabolism in DKO mice might be associated with low BAs. CA, DCA, and UDCA feeding activated FXR signals with tissue specificity. Dietary CA and DCA similarly altered tissue BA profiles to be less hydrophobic, while UDCA promoted a more hydrophobic tissue BA pool with the profiles shifted toward non-12α-OH BAs and secondary BAs. However, UDCA did not offer any overt protective effects as expected. These findings allow us to determine the precise effects of individual BAs in vivo on BA-FXR signaling and overall BA homeostasis in liver physiology and pathologies.

Comparison of three different anastomotic methods of sleeve gastrectomy with transit bipartition using an obese rodent model

The long-term effects and safety of single-anastomosis sleeve ileal (SASI) bypass have not been confirmed. The one anastomosis procedure carries the risk of bile reflux, and Braun anastomosis has the capacity to reduce bile reflux. This study was designed to compare the influences of bile reflux and histological changes in the esogastric sections of rats. Obese Sprague–Dawley rats underwent sleeve gastrectomy with transit bipartition (RYTB) (n = 12), SASI (n = 12), SASI bypass with Braun anastomosis (BTB) (n = 12), esojejunostomy (EJ) (n = 12), and SHAM (n = 8) surgery. During the 12-week follow-up period, weight changes, glucose improvement, and changes in serum nutrition were evaluated. Histological expression and bile acid concentration in the rats in all groups were also evaluated. No significant differences in weight loss and glucose improvements were observed in the RYTB, SASI, and BTB groups. The RYTB and BTB groups had significantly lower bile acid concentration and albumin levels than the SASI group. In addition, mucosal height in the RYTB and BTB groups was significantly lower than in the SASI group. Braun anastomosis had a significant effect on anti-reflux. BTB may be a superior primary procedure due to its potential for parallel bariatric and metabolic improvements, effective anti-reflux effects, simplified operations, and avoidance of severe malnutrition. Further clinical studies are needed to confirm these findings.

Peripheral Vascular Disease and Carotid Artery Disease Are Associated with Decreased Bile Acid Excretion.

Low bile acid excretion (BAE) is associated with a higher risk of coronary artery disease (CAD) and cerebrovascular disease (stroke). This study investigated BAE in patients with peripheral vascular disease (PVD) and carotid artery disease (CA) and those without these diseases, compared to patients with CAD, stroke, or no evidence of atherosclerosis. Patients with complaints of chest pain-suspected CAD, syncope, stroke/TIA, severe headache, intermittent claudication, or falls were enrolled. All received a 4-day standard diet with 490 mg of cholesterol and internal standard copper thiocyanate. Fecal BAE was measured using gas-liquid chromatography. One hundred and three patients, sixty-eight (66%) men and thirty-five women (34%), mean age range 60.9 ± 8.9 years, were enrolled in this prospective, 22-year follow-up study. Regression analysis showed that advanced age, total BAE, and excretion of the main fractions were the only significant independent factors that predicted prolonged survival (p < 0.001). Twenty-two years' follow-up revealed only 15% of those with BAE <262.4 mg/24 h survived, compared to >60% of participants without atherosclerosis and a mean BAE of 676 mg/24 h. BAE was lower in patients with polyvascular atherosclerosis than in those with involvement of 1-3 vascular beds. Pearson correlations were found between total BAE and various fractions of BA, as well as HDL cholesterol. BAE and short-term survival were decreased among patients with PVD compared to those with CAD or stroke. Low BAE should be considered a valuable and independent risk factor for PVD.

Interactive effects of gestational diabetes mellitus and maximum level of total bile acid in maternal serum on adverse pregnancy outcomes in women with intrahepatic cholestasis of pregnancy

ObjectiveTo study the combined effect of gestational diabetes mellitus (GDM) and maximum level of maternal serum total bile acid (TBA) on the incidence of adverse pregnancy outcomes in women with intrahepatic cholestasis of pregnancy (ICP).MethodsThis was an observational study with 724 women with ICP. Perinatal outcomes were compared by the presence of GDM. Logistic regression was used to assess the independent and multiplicative interactions of GDM and maximum maternal serum TBA on adverse pregnancy outcomes. Additive interactions were calculated using an Excel sheet developed by Andersson to calculate relative excess risks.ResultsThe incidence of GDM in patients with ICP was 21.55%. Maternal age, pre-pregnancy weight, parity, and gravidity were positively correlated with GDM. Hypertensive disorders of pregnancy (HDP) and fetal distress rates were higher in the GDM vs. non-GDM group. There were no significant differences in biochemical outcomes (i.e., Triglyceride (TG), low density lipoprotein (LDL), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bile acid (TBA)) between the two groups. In terms of adverse pregnancy outcomes, GDM was only associated with maximum TBA concentration for cesarean section. No additive or pairwise interactions were detected between GDM and maximum TBA concentration and HDP, PPH, preterm delivery, LGA, SGA, and cesarean section.ConclusionGDM independently contributes to adverse pregnancy outcomes among women with ICP. However, the combined effects of GDM and maximum TBA concentration on adverse pregnancy outcomes do not appear to be multiplicative or additive.

Bacteriocin potency test of lactic acid bacteria (LAB) isolated from rumen of Bali cattle against low pH and bile salt

Background: Lactic acid bacteria (LAB) are a group of probiotic bacteria, which are not at risk and can even have a positive impact on human and animal health. As a source of probiotics, the application of these bacteria must be resistant to environmental conditions such as resistance to low pH and gastrointestinal bile acids. This study aimed to determine the probiotic potential of lactic acid bacteria isolated from the rumen and colon of Bali cattle by testing their resistance to low pH and bile salts. Methods: The study began with the cultivation of isolates from the rumen and colon of Bali cattle including growth on liquid MRS media, catalase test, and Gram staining. The second stage involved testing the isolate's resistance to low pH (pH 2, 3, and 4) and testing NaDC with concentrations of 0.2 mM, 0.4 mM, and 0.6 mM. Results: Tests showed that of the 10 isolates from Bali cattle rumen tested, it was found that all had high tolerance at low pH, namely growing well at pH 2 and NaDC levels up to 0.6 mM. The results obtained corroborate the results of previous studies on the resistance of lactic acid bacteria isolates from the gastrointestinal tract of Bali cattle to low pH and bile salt levels as a condition for application as a probiotic. Conclusion: The resistance of the isolate to low pH and NaDC shows that LAB isolates from the rumen of Bali cattle have the potential to be used as a reliable source of probiotics.

Abstract 4233: The anti-genotoxic function of Lactobacillus species in the context of bile-mediated DNA damage and inflammation in experimental models of GERD

Abstract Lactobacillus species are commensal organisms with probiotic characteristics found in the human oral cavity and gastrointestinal tract. It has been shown that gram-positive organisms, including lactobacilli, make up the majority of the microbiome in the healthy human esophagus. The general consensus is that the microbiome shifts from gram-positive to gram-negative bacteria during gastroesophageal reflux disease (GERD). In patients suffering from GERD, the esophageal tissue is injured by the low pH and bile acids present in the refluxate, resulting in Barrett’s esophagus if untreated. Interestingly, it has been reported that there is a proportional increase in gram-positive lactobacilli within the esophagus during the progression from GERD to Barrett’s esophagus, and finally esophageal adenocarcinoma. To investigate how lactobacilli are able to colonize and survive in a bile-rich environment of the esophagus during GERD, we first exposed three Lactobacillus species (L. acidophilus, L. plantarum, and L. fermentum) to cholate/deoxycholate bile salts or ox-bile as a more physiological model for human reflux. All three species exhibited bile resistance, in addition to bile adaptation after pre-exposure to sub-lethal concentrations. When assessed for changes in bacterial cell surface hydrophobicity, an indicator for bacterial adhesion to various surfaces, both bile types led to an increase of hydrophobicity in L. plantarum and L. fermentum, while L. acidophilus remained high. This provides mechanistic insight into how Lactobacillus species' attachment and colonization remain during reflux-related diseases. Next, we assessed the host-microbe interactions between lactobacilli and esophageal cells and the role these probiotic organisms may have in disease prevention. Acidic bile salts can induce inflammation and DNA damage to esophageal tissue through ROS during GERD, yet we found that the presence of lactobacilli co-cultured with bile-treated esophageal epithelial cells aids in the repair of bile-induced DNA damage in addition to NFKB reductions. To further investigate the host-microbe interactions, we supplemented epithelial cells with lactobacilli postbiotic metabolites and assessed cell viability during 48 hours of growth. Our current preliminary data show that postbiotic supplementation increases cell viability, providing insight into why lactobacilli are present within the normal and diseased human esophagus. This study demonstrates how the colonization of the esophagus during GERD with lactobacilli is based on their adaptability and survival due to changes in hydrophobicity thereby sustaining attachment. Furthermore, the anti-genotoxic and anti-inflammatory effects these organisms exhibit make them of significant interest in the prevention of Barrett’s esophagus and esophageal adenocarcinoma in patients with GERD. Citation Format: Joshua Bernard, Divya Joshi, Claudia Andl. The anti-genotoxic function of Lactobacillus species in the context of bile-mediated DNA damage and inflammation in experimental models of GERD. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4233.

Multilayer coatings containing red ginseng dietary fibre improve the survivability and stability of probiotic bacteria

SummaryMaintaining the viability of probiotics is critical for maximising their functionality. In this study, tara gum, basic amino acids, rice protein and red ginseng dietary fibre were sequentially applied to encapsulate various probiotic strains to improve their viability and enhance their adhesion to intestinal cells. Compared with uncoated control strains, multilayer‐coated probiotic strains exhibited higher survival rates under low pH conditions (maximum survival: 81.8% for Lactobacillus casei) and bile acid conditions (&gt;50% survival for Lactobacillus rhamnosus). Multicoating also increased the ability of probiotic strains to adhere to intestinal epithelial cells. For example, encapsulated L. reuteri exhibited 56.9% adhesion, which was approximately four‐fold higher than that of the uncoated strain. Moreover, compared with the uncoated strains, multicoated strains exhibited significantly improved storage stability under various temperatures after freeze‐drying. Therefore, the quadruple‐coating technology used in this study enhances the viability and stability of probiotic strains, which is a key advantage from the industrial perspective.

P912 Increased Primary Bile Acids with Ileocolonic Resection Impact Ileal Inflammation and Gut Microbiota in Inflammatory Bowel Disease

Abstract Background A majority of Crohn’s disease (CD) patients require surgery. Ileitis recurs after most ileocolectomies and is a critical determinant for outcomes. The impact of ileocolectomy-induced bile acid (BA) perturbations on intestinal microbiota and inflammation are unknown. We characterized relationships between ileocolectomy, stool BA, microbiota, and intestinal inflammation in inflammatory bowel disease (IBD). Methods Validated IBD clinical and endoscopic assessments were prospectively collected. Matched primary and secondary BA concentrations measured in stool using Agilent Quadrupole Time of Flight Liquid chromatography-mass spectrometry were compared based on ileocolectomy and ileitis status. Primary BA thresholds for ileitis were evaluated using area under the receiver operating characteristic curve analyses. In CD, endoscopic remission was defined as SES-CD &amp;lt;3 or Rutgeerts &amp;lt;i2b. Ileal ER was defined as ileal SES-CD ≤ 1 and colonic ER was defined as colonic SES-CD≤2 without any segment &amp;gt;1. In UC, ER was defined as UC-ESS ≤ 1. Metagenomic sequencing profiled microbial composition and function. Relationships between ileocolectomy, BA and microbiota were assessed. Results In 166 patients, elevated primary and secondary BA existed with ileocolectomy. With ileitis, only primary BA (795 nMol/g vs 398 nMol/g, p=0.009) were higher compared to without ileitis. The optimal primary BA threshold (≥228nMol/g) identified ileitis on multivariable analysis (OR=2.3, p=0.04). Similar primary (471 nMol/g vs. 606 nMol/g, p=0.8) and secondary (382 nMol/g vs. 242 nMol/g, p=0.2) BA concentrations existed with and without colonic inflammation. Microbial diversity (Shannon index, p=0.0006), Faecalibacterium prausnitzii and O-acetylhomoserine aminocarboxypropyltransferase (MetY, p=0.0002) were decreased with elevated primary BA. Amongst ileocolectomy patients, only those with elevated primary BA had diversity (p=0.01), F.prausnitzii and MetY (p=0.04) reductions. Those with both ileocolectomy and intermediate (p=0.002) or high (≥228nMol/g, p=9.1e-11) ) primary BA had reduced F.prausnitzii compared to without ileocolectomy (Figure 1). Those with ileocolectomy and low (&amp;lt;29.2nMol/g) primary BA had similar F.prausnitzii as those without ileocolectomy (P=0.13). MetY was reduced with ileitis (p=0.02). Conclusion Elevated primary bile acids were associated with ileitis, and reduced microbial diversity, F.prausnitzii abundance, and enzymatic expression of MetY (acetate and L-methionine producing enzyme expressed by F.prausnitzii) and were the only factor associated with these findings after ileocolectomy.

Farnesoid X receptor antagonizes macrophage-dependent licensing of effector T lymphocytes and progression of sclerosing cholangitis.

Immune-mediated bile duct epithelial injury and toxicity of retained hydrophobic bile acids drive disease progression in fibrosing cholangiopathies such as biliary atresia or primary sclerosing cholangitis. Emerging therapies include pharmacological agonists to farnesoid X receptor (FXR), the master regulator of hepatic synthesis, excretion, and intestinal reuptake of bile acids. Unraveling the mechanisms of action of pharmacological FXR agonists in the treatment of sclerosing cholangitis (SC), we found that intestinally restricted FXR activation effectively reduced bile acid pool size but did not improve the SC phenotype in MDR2-/- mice. In contrast, systemic FXR activation not only lowered bile acid synthesis but also suppressed proinflammatory cytokine production by liver-infiltrating inflammatory cells and blocked progression of hepatobiliary injury. The hepatoprotective activity was linked to suppressed production of IL1β and TNFα by hepatic macrophages and inhibition of TH1/TH17 lymphocyte polarization. Deletion of FXR in myeloid cells caused aberrant TH1 and TH17 lymphocyte responses in diethoxycarbonyl-1,4-dihydrocollidine-induced SC and rendered these mice resistant to the anti-inflammatory and liver protective effects of systemic FXR agonist treatment. Pharmacological FXR activation reduced IL1β and IFNγ production by liver- and blood-derived mononuclear cells from patients with fibrosing cholangiopathies. In conclusion, we demonstrate FXR to control the macrophage-TH1/17 axis, which is critically important for the progression of SC. Hepatic macrophages are cellular targets of systemic FXR agonist therapy for cholestatic liver disease.

Bile acid profiles in choledocholithiasis and their ability to predict common bile duct stone recurrence after endoscopic retrograde cholangiopancreatography treatment.

This study aimed to explore the alteration of bile acid (BA) profiles in patients with choledocholithiasis (CDC) and construct a prediction model for evaluating the risk of common bile duct stone (CBDS) recurrence after endoscopic treatment. A total of 320 patients (218 with CDC and 102 with nonneoplastic polyps) were enrolled. The serum BA profiles were compared between groups. Both diagnostic score of CDC and prognostic risk score of CBDS recurrence based on BAs were established by least absolute shrinkage and selection operator regression. A nomogram model was developed combining the risk score with clinical factors selected by Cox regression analysis. The BA profiles of patients with CDC were different from those of controls, which was mainly exhibited by an increase in conjugated BAs and the ratio of primary to secondary BA and a decrease in the hydrophobic BA ratio. The diagnostic model effectively distinguished patients with CDC from controls with an area under the curve of 0.763. Patients with CDC with a low BA risk score exhibited a high possibility of stone recurrence-free survival. The hazard ratios of history of cholecystectomy, multiple stones (n ≥ 2), bile duct angulation ≥132.7, and low BA risk score were 2.43, 4.18, 0.42, and 0.31, respectively. The serum BA profiles were altered in patients with CDC and could be used to distinguish patients with CDC from controls. The nomogram model developed for predicting the risk of CBDS recurrence in patients with CDC after endoscopic retrograde cholangiopancreatography treatment had high accuracy and clinical usability.

Intratracheal exposure to polyhexamethylene guanidine phosphate disrupts coordinate regulation of FXR-SHP-mediated cholesterol and bile acid homeostasis in mouse liver

A public health crisis in the form of a significant incidence of fatal pulmonary disease caused by repeated use of humidifier disinfectants containing polyhexamethylene guanidine phosphate (PHMG) recently arose in Korea. Although the mechanisms of pulmonary fibrosis following respiratory exposure to PHMG are well described, distant-organ effect has not been reported. In this study, we investigated whether intratracheal administration of PHMG affects liver pathophysiology and metabolism. Our PHMG mouse model showed a significant decrease in liver cholesterol level. An mRNA-seq analysis of liver samples revealed an alteration in the gene expression associated with cholesterol biosynthesis and metabolism to bile acids. The expression of genes involved in cholesterol synthesis was decreased in a real-time PCR analysis. To our surprise, we found that the coordinate regulation of cholesterol and bile acid homeostasis was completely disrupted. Despite the decreased cholesterol synthesis and low bile acid levels, the farnesoid X receptor/small heterodimer partner pathway, which controls negative feedback of bile acid synthesis, was activated in PHMG mice. As a consequence, gene expression of Cyp7a1 and Cyp7b1, the rate-limiting enzymes of the classical and alternative pathways of bile acid synthesis, was significantly downregulated. Notably, the changes in gene expression were corroborated by the hepatic concentrations of the bile acids. These results suggest that respiratory exposure to PHMG could cause cholestatic liver injury by disrupting the physiological regulation of hepatic cholesterol and bile acid homeostasis.

Lower bile acids as an independent risk factor for renal outcomes in patients with type 2 diabetes mellitus and biopsy-proven diabetic kidney disease.

AimsAbnormalities of glucolipid metabolism are critical mechanisms involved in the progression of diabetic kidney disease (DKD). Bile acids have an essential role in regulating glucolipid metabolism. This study investigated the clinicopathological characteristics of DKD patients with different bile acid levels and explored the relationship between bile acids and renal outcomes of DKD patients.MethodsWe retrospectively reviewed and evaluated the histopathological features and clinical features of our cohort of 184 patients with type 2 diabetes mellitus and biopsy-proven DKD. Patients were divided into the lower bile acids group (≤2.8 mmol/L) and higher bile acids group (>2.8 mmol/L) based on the cutoff value of bile acids obtained using the time-dependent receiver-operating characteristic curve. Renal outcomes were defined as end-stage renal disease (ESRD). The influence of bile acids on renal outcomes and correlations between bile acids and clinicopathological indicators were evaluated.ResultsBile acids were positively correlated with age (r = 0.152; P = 0.040) and serum albumin (r = 0.148; P = 0.045) and negatively correlated with total cholesterol (r = -0.151; P = 0.041) and glomerular class (r = -0.164; P =0.027). During follow-up, 64 of 184 patients (34.78%) experienced progression to ESRD. Lower levels of proteinuria, serum albumin, and bile acids were independently associated with an increased risk of ESRD (hazard ratio, R=5.319; 95% confidence interval, 1.208–23.425).ConclusionsBile acids are an independent risk factor for adverse renal outcomes of DKD patients. The serum level of bile acids should be maintained at more than 2.8 mmol/L in DKD patients. Bile acid analogs or their downstream signaling pathway agonists may offer a promising strategy for treating DKD.

Dairy-Based Probiotic-Fermented Functional Foods: An Update on Their Health-Promoting Properties

Numerous studies have shown a link between the consumption of fermented dairy foods and improved health outcomes. Since the early 2000s, especially probiotic-based fermented functional foods, have had a revival in popularity, mostly as a consequence of claims made about their health benefits. Among them, fermented dairy foods have been associated with obesity prevention and in other conditions such as chronic diarrhea, hypersensitivity, irritable bowel syndrome, Helicobacter pylori infection, lactose intolerance, and gastroenteritis which all are intimately linked with an unhealthy way of life. A malfunctioning inflammatory response may affect the intestinal epithelial barrier’s ability to function by interfering with the normal metabolic processes. In this regard, several studies have shown that fermented dairy probiotics products improve human health by stimulating the growth of good bacteria in the gut at the same time increasing the production of metabolic byproducts. The fermented functional food matrix around probiotic bacteria plays an important role in the survival of these strains by buffering and protecting them from intestinal conditions such as low pH, bile acids, and other harsh conditions. On average, cultured dairy products included higher concentrations of lactic acid bacteria, with some products having as much as 109/mL or g. The focus of this review is on fermented dairy foods and associated probiotic products and their mechanisms of action, including their impact on microbiota and regulation of the immune system. First, we discussed whey and whey-based fermented products, as well as the organisms associated with them. Followed by the role of probiotics, fermented-product-mediated modulation of dendritic cells, natural killer cells, neutrophils, cytokines, immunoglobulins, and reinforcement of gut barrier functions through tight junction. In turn, providing the ample evidence that supports their benefits for gastrointestinal health and related disorders.

Effect of dietary NSP level and bile acid supplementation on nutrient digestibility and the bile acid metabolism in rainbow trout (Oncorhynchus mykiss)

The effects of dietary bile acid supplementation (BAS) on apparent digestibility coefficients (ADC) and the bile acid metabolism in rainbow trout (Oncorhynchus mykiss) were investigated for diets differing in non-starch polysaccharide (NSP) level. Four experimental diets were formulated according to an 2 by 2 factorial design. A low-NSP and High-NSP diet (0 vs. 160 g kg−1 inclusion of an NSP-rich ingredient mixture) were first formulated. The aim of this was to create differences in the amount of faecal waste produced, and consequently as previously shown in rainbow, the amount of faecal bile acid loss (FBAL). Both NSP-level diets were tested with 0% and 0.3% BAS (0 vs. 3 g kg−1 inclusion of a bile acid mixture). The bile acid mixture contained taurocholic acid (T-CA) and glycocholic acid (G-CA) in a 2:1 ratio. Glycocholic acid does not naturally occur in trout and was used as marker to see if supplemented bile acids are efficiently absorbed and enter enterohepatic circulation (EHC). Fish were fed to apparent satiation for 42 days. Dietary NSP level did not enhance FBAL. BAS was beneficial for fat ADC, but not for the ADC of protein and carbohydrates. BAS improved fat ADC regardless of NSP level, which suggests that bile acids are a limiting factor for fat digestion in rainbow trout. Total bile acid synthesis was a 4-fold lower in fish fed the 0.3% BAS diets compared to the 0% BAS diets. Lower bile acid synthesis with BAS occurred alongside enlarged body and liver + gallbladder bile acid pools and a higher content of bile acids in the chyme. These higher bile acid levels most likely caused a negative feedback inhibition of bile acid synthesis. Negative synthesis rates of G-CA were found when feeding the 0.3% BAS diets, which suggests that this bile acid is catabolised or converted into other bile acid types in rainbow trout. The enlarged pool of T-CA, but especially of the body foreign G-CA, with BAS in both the body and liver + gallbladder shows that dietary bile acids are effectively taking part in EHC. The relative absorption of T-CA and G-CA over the different intestinal compartments was comparable, which shows that EHC does not differentiate between T-CA and G-CA. While relative absorption of bile acids was highest between the distal intestine and the faeces, the absolute decrease in chyme bile acid content was highest between the pyloric region and the mid intestine. The latter shows that significant bile acid absorption occurs more proximal in the intestine of rainbow trout than previously thought.

Abstract 3061: Elevated bile acid metabolism is associated with breast cancer microbiome, less cell proliferation, and better survival

Abstract BACKGROUND: Bile acids are generated and secreted by hepatocytes and are involved in intestinal circulation. Recently it has been reported that specific bile acids are accumulated in the breast cancer tumor microenvironment (TME), leading to a favorable prognosis for patients and reducing the aggressiveness and metastatic potential of the cancer. We hypothesized that breast cancers with increased bile acid metabolism may have a favorable clinical outcome due to the suppression of cancer cell proliferation. MATERIALS AND METHODS: We analyzed total of 6285 patients from three independent breast cancer cohorts with TCGA as an exploring cohort and METABRIC, GSE96058 as validation cohorts. We divided each cohort into "high" and "low" groups by the top and bottom quartiles of the score following the previous reports. RESULTS: High bile acid metabolism breast cancer enriched multiple metabolic pathway gene sets such as fatty acid and xenobiotic metabolism, as well as adipogenesis and protein secretion by gene set enrichment analysis (GSEA). Adipocytes and preadipocytes were significantly infiltrated in the high score group. Considering the possibility that activation of bile acid metabolism is due to accumulation of microbiome-derived bile acids in breast cancer, we identified that four microorganisms (Anaerococcus, Collimonas, Gammaretrovirus and Hymenobacter) significantly correlated with the bile acid metabolism using TCGA 16s RNA seq data. Surprisingly, protein secretion gene set was significantly enriched to tumors that are abundant in three out of four of these bacterial species. This may suggest that bile acid metabolism are elevated in response to bile acids secreted by the microbiome present in breast cancer TME. The bile acid metabolism was highest in ER+HER2- and lowest in triple-negative, the most aggressive form of breast cancer. The score was negatively correlated with Ki67 gene expression and histological grade, consistent with previous reports that breast cancers with high bile acid accumulation were less proliferative. In agreement, breast cancers with low bile acid metabolism was associated with significantly high silent and non-silent mutation rates, Intratumor Heterogeneity, Proliferation score and Homologous Recombination Defects, and enriched G2M checkpoint gene set. Finally, survival analysis showed that high bile acid metabolism group had significantly better disease free, disease specific and overall survival. CONCULUSIONS: Bile acid metabolism was associated with involvement of microbiome in TME, the suppression of cell proliferation, and better prognosis in breast cancer. Citation Format: Rongrong Wu, Quratulain Sabih, Masanori Oshi, Takashi Ishikawa, Li Yan, Kazuaki Takabe. Elevated bile acid metabolism is associated with breast cancer microbiome, less cell proliferation, and better survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3061.

Decreased bile acid metabolism and association with prognosis reflecting microbiome in tumor microenvironment involved in cancer cell proliferation in breast cancer.

e12539 Background: Bile acids are metabolized by the gut microbiome and are involved in fat absorption. Contrary to their carcinogenic role in gastrointestinal cancers, bile acids have been reported to inhibit cancer cell proliferation in breast cancer. We hypothesized that activation of bile acid metabolism is associated with a better prognosis based on previous reports regarding the antitumor effects of bile acids in breast cancer cells. Methods: A total of 6050 patients from three large open primary breast cancer cohorts (GSE96058, METABRIC, and TCGA) were analyzed by bile acid metabolism scores calculated by gene set variation analysis, and the association with the microbiome of the breast cancer tumor microenvironment in TCGA was also investigated. Results: We found that disease free, disease specific and overall survival was significantly improved in the high bile acid metabolism group, which was validated by three large breast cancer cohorts. However, apoptosis, ROS, and unfolded protein response gene sets were not found to be enriched in the high bile acid metabolism group, despite the expectation that oxidative stress-induced apoptosis would lead to improved survival. Several metabolic pathways and pathways associated with bile acid production and regulation were enriched in this group. On the other hand, Ki67 and nuclear grade were higher, and several cell proliferation-related gene sets were upregulated in the low bile acid metabolism group, especially the G2M checkpoint in all cohorts. In association with the higher cell proliferation, the low bile acid metabolism group showed higher mutation load, immune activation, and infiltration of anti-cancer immune cells. We further investigated that the composition of the microbiome in each group and four species that demonstrated significant abundance in the high bile acid metabolism group and three species in the low bile acid metabolism group. Surprisingly, almost all the cell proliferation-related gene sets from Hallmark were enriched in the three microorganisms-rich groups specific for low bile acid metabolism breast cancer. This was not the case for the microorganisms specific to high bile acid metabolism. Conclusions: Clinical relevance of bile acid metabolism in breast cancer is that low bile acid metabolism with abundant Lactobacillus, Ruegeria, and Marichromatium is associated with highly proliferative cancer and worse survival, rather than the growth suppression effect of bile acids.

English

Breast feeding has critical effects on the newborns and either mother&rsquo;s health. Some of such health-improving effects of the mother&rsquo;s milk is associated with the beneficial microbes, lactic acid bacteria (LAB), which are normally present in the mother&rsquo;s milk. Thus, human milk-associated lactobacilli were isolated in this study and some of their probiotic properties was investigated. Afterwards, Lactobacillus strains were screened for low pH and bile acids tolerance. Molecular identification was carried out using 16SrDNA and polymerase chain reaction (PCR). Antibiotic resistance was evaluated with disk diffusion assay and the inhibitory effect of isolates on pathogenic bacteria was examined with well assay and zone inhibition. Isolation experiments resulted in 122 human milk- associated lactobacilli belonging to 12 species. The most dominant species was Lactobacillus casei followed by Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus gasser, respectively. Screening for probiotic properties showed that 19 isolates, belonging to, Lactobacillus, have interesting probiotic characteristics. The most prevalent antibiotic resistance was observed in case of vancomycin (63.15%) and no drug resistance was detected for chloramphenicol, penicillin, rifampin (0%). Three Lactobacillus strains, designated as L4, L14 and L16, were found as potential probiotic strains since they have indicated promising inhibitory effects against the studied pathogenic bacterial strains. Our results shed light on the considerable diversity of lactobacilli in human breast milk. Furthermore, the candidate probiotic strains detected in this research might be used as potential probiotic strains. &nbsp; Key words: Breast milk, Lactobacillus, probiotics, inhibitory effect, polymerase chain reaction.