Distinct metabolomic and lipidomic profiles in serum samples of patients with primary sclerosing cholangitis.

Intoduction: Identification of specific metabolome and lipidome profile of patients with primary sclerosing cholangitis (PSC) is crucial for diagnosis, targeted personalized therapy, and more accurate risk stratification. Methods: Nuclear magnetic resonance (NMR) spectroscopy revealed an altered metabolome and lipidome of 33 patients with PSC [24 patients with inflammatory bowel disease (IBD) and 9 patients without IBD] compared with 40 age-, sex-, and body mass index (BMI)-matched healthy controls (HC) as well as 64 patients with IBD and other extraintestinal manifestations (EIM) but without PSC. Results: In particular, higher concentrations of pyruvic acid and several lipoprotein subfractions were measured in PSC in comparison to HC. Of clinical relevance, a specific amino acid and lipid profile was determined in PSC compared with IBD and other EIM. Discussion: These results have the potential to improve diagnosis by differentiating PSC patients from HC and those with IBD and EIM.

Urinary soluble CD163 is a putative non-invasive biomarker for primary sclerosing cholangitis.

Soluble CD163 (sCD163) is a selective marker of macrophages whose circulating levels have been found to be induced in patients with active inflammatory bowel disease (IBD). Urinary proteins are emerging as non-invasive diagnostic biomarkers, and here, sCD163 levels were measured in the urine of 18 controls and 63 patients with IBD by enzyme-linked immunosorbent assay. Urinary sCD163 levels did, however, not differentiate IBD patients from controls. Analysis of sCD163 in the serum of 51 of these patients did not show higher levels in IBD. Primary sclerosing cholangitis (PSC) is often associated with IBD, and sCD163 was higher in the urine of the 21 patients and in the serum of the 13 patients with PSC compared to patients with IBD. Of clinical relevance, urinary sCD163 levels were higher in PSC patients compared to those with other chronic liver diseases (n = 16), while serum sCD163 levels were comparable between the two groups. Serum sCD163 of IBD and PSC patients positively correlated with serum C-reactive protein. Serum creatinine and glomerular filtration rate, surrogate markers for renal function, did not significantly correlate with urinary or serum sCD163 levels in IBD or PSC patients. Moreover, urinary sCD163 was not related to fecal calprotectin levels whereas serum sCD163 of IBD patients showed a positive trend. PSC associated with IBD and PSC without underlying IBD had similar levels of urinary sCD163 while serum sCD163 tended to be higher in the latter group. In PSC patients, urinary sCD163 did not correlate with serum aminotransferase levels, gamma glutamyl transferase, alkaline phosphatase, bilirubin or the Model for End Stage Liver Disease score. Ursodeoxycholic acid was prescribed to our PSC patients and fecal levels of ursodeoxycholic acid and its conjugated forms were increased in PSC compared to IBD patients. Otherwise, fecal bile acid levels of IBD and PSC patients were almost identical, and were not correlated with urinary and serum sCD163 in PSC. In summary, our study identified urinary sCD163 as a potential biomarker for PSC.

Unique Metabolomic and Lipidomic Profile in Serum From Patients With Crohn's Disease and Ulcerative Colitis Compared With Healthy Control Individuals.

BACKGROUND: Accurate biomarkers for disease activity and progression in patients with inflammatory bowel disease (IBD) are a prerequisite for individual disease characterization and personalized therapy. We show that metabolic profiling of serum from IBD patients is a promising approach to establish biomarkers. The aim of this work was to characterize metabolomic and lipidomic serum profiles of IBD patients in order to identify metabolic fingerprints unique to the disease. METHODS: Serum samples were obtained from 55 patients with Crohn's disease (CD), 34 patients with ulcerative colitis (UC), and 40 healthy control (HC) individuals and analyzed using proton nuclear magnetic resonance spectroscopy. Classification of patients and HC individuals was achieved by orthogonal partial least squares discriminant analysis and univariate analysis approaches. Disease activity was assessed using the Gastrointestinal Symptom Rating Scale. RESULTS: Serum metabolome significantly differed between CD patients, UC patients, and HC individuals. The metabolomic differences of UC and CD patients compared with HC individuals were more pronounced than the differences between UC and CD patients. Differences in serum levels of pyruvic acid, histidine, and the branched-chain amino acids leucine and valine were detected. The size of low-density lipoprotein particles shifted from large to small dense particles in patients with CD. Of note, apolipoprotein A1 and A2 serum levels were decreased in CD and UC patients with higher fecal calprotectin levels. The Gastrointestinal Symptom Rating Scale is negatively associated with the concentration of apolipoprotein A2. CONCLUSIONS: Metabolomic assessment of serum samples facilitated the differentiation of IBD patients and HC individuals. These differences were constituted by changes in amino acid and lipoprotein levels. Furthermore, disease activity in IBD patients was associated with decreased levels of the atheroprotective apolipoproteins A1 and A2.

The metabolic and lipidomic serum profile of patients with inflammatory bowel disease was analyzed using proton nuclear magnetic resonance spectroscopy. A significantly altered profile in comparison with healthy control individuals was identified, characterized by more atherogenic properties.

Altered fecal bile acid composition in active ulcerative colitis.

BACKGROUND: Disturbed bile acid homeostasis associated with a rise of primary and a decline of secondary bile acids is a consistent finding in inflammatory bowel diseases (IBDs). Whether fecal bile acids may emerge as biomarkers for IBD diagnosis and disease severity is less clear. Our study aimed to identify associations of 18 fecal bile acid species with IBD entity and disease activity. METHODS: Stool samples of 62 IBD patients and 17 controls were collected. Eighteen fecal bile acid species were quantified by LC-MS/MS using stable isotope dilution. Lipid levels normalized to a dry weight of the fecal homogenates and ratios of single bile acid species to total bile acid levels were used for calculations. RESULTS: IBD patients exhibited altered primary and secondary bile acid ratios in stool, with notable distinctions between ulcerative colitis (UC) compared to Crohn's disease (CD) and healthy controls. Fecal calprotectin was negatively correlated with glycolithocholic acid (GLCA) and hyodeoxycholic acid (HDCA) in UC. These bile acids were reduced in stool of UC patients with fecal calprotectin levels > 500 µg/g compared to UC patients with low calprotectin levels. Moreover, negative associations of six secondary bile acids with C-reactive protein (CRP) existed in UC. In CD patients, fecal bile acids did not correlate with CRP or fecal calprotectin. Diarrhoea is common in IBD, and UC patients with diarrhoea had reduced deoxycholic acid (DCA), glycine conjugated DCA (GDCA) and lithocholic acid in stool in contrast to patients with normal stool consistency. Fecal bile acid levels were not associated with diarrhoea in CD patients. UC patients treated with mesalazine had increased levels of fecal GDCA whereas no such changes were observed in CD patients. Bile acid levels of CD and UC patients treated with biologicals or corticosteroids did not change. Relative levels of GHDCA (specificity: 79%, sensitivity: 67%) and glycochenodeoxycholic acid (specificity: 74%, sensitivity: 63%) were the most specific to distinguish UC from CD. CONCLUSION: Disrupted fecal bile acid homeostasis is associated with disease severity and disease symptoms in UC but not in CD, potentially aiding in distinguishing IBD subtypes and classifying the pathophysiology of diarrhoea in UC.

Fecal short chain fatty acids and urinary 3-indoxyl sulfate do not discriminate between patients with Crohn´s disease and ulcerative colitis and are not of diagnostic utility for predicting disease severity.

BACKGROUND: Urinary 3-indoxyl sulfate levels as well as fecal short chain fatty acid (SCFA) concentrations are surrogate markers for gut microbiota diversity. Patients with inflammatory bowel diseases (IBDs) and patients with primary sclerosing cholangitis (PSC), a disease closely associated with IBD, have decreased microbiome diversity. In this paper, the fecal SCFAs propionate, acetate, butyrate and isobutyrate of patients with IBD and patients with PSC-IBD and urinary 3-indoxyl sulfate of IBD patients were determined to study associations with disease etiology and severity. METHODS: SCFA levels in feces of 64 IBD patients and 20 PSC-IBD patients were quantified by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Urinary 3-indoxyl sulfate levels of 45 of these IBD patients were analysed by means of reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry. Feces of 17 healthy controls and urine of 13 of these controls were analyzed in parallel. These cohorts had comparable sex distribution and age. RESULTS: Urinary 3-indoxyl sulfate concentrations (normalized to urinary creatinine levels) was increased (P = 0.030) and fecal isobutyrate levels (normalized to dry weight of the stool sample) of IBD patients were decreased (P = 0.035) in comparison to healthy controls. None of the analyzed metabolites differed between patients with Crohn´s disease (CD) and patients with ulcerative colitis (UC). Fecal acetate and butyrate positively correlated with fecal calprotectin (P = 0.040 and P = 0.005, respectively) and serum C-reactive protein (P = 0.024 and P = 0.025, respectively) in UC but not CD patients. UC patients with fecal calprotectin levels above 150 µg/g, indicating intestinal inflammatory activity, had higher fecal acetate (P = 0.016), butyrate (P = 0.007) and propionate (P = 0.046) in comparison to patients with fecal calprotectin levels < 50 µg/g. Fecal SCFA levels of PSC-IBD and IBD patients were comparable. CONCLUSIONS: Current findings suggest that analysis of urinary 3-indoxyl-sulfate as well as fecal SCFAs has no diagnostic value for IBD and PSC-IBD diagnosis or monitoring of disease severity.

Urinary chemerin as a potential biomarker for inflammatory bowel disease.

Purpose: Systemic levels of the adipokine chemerin are elevated in different inflammatory conditions such as inflammatory bowel disease (IBD). In IBD, chemerin protein expression in colon mucosa is induced and serum chemerin levels are increased. Aim of this study was to identify chemerin protein in human feces and/or urine and to evaluate a possible association with IBD activity. Materials and methods: Feces and urine of 40 patients with IBD and the respective sera of 34 patients were collected. Chemerin levels were analyzed by immunoblot in feces and urine samples. In addition, enzyme-linked immunosorbent assay (ELISA) was used to measure chemerin in all urine, feces and serum samples of the patients and in urine of 17 healthy controls. Results: Chemerin was not detectable in 80% of the human feces samples by ELISA. Chemerin in human urine was detected by immunoblot and ELISA. Compared to serum levels, urinary concentration was about 6,000-fold lower. Urinary chemerin did not differ between patients with ulcerative colitis (n = 15) and Crohn's disease (n = 25). Urinary chemerin was not related to its serum levels, did not correlate with serum C-reactive protein level and negatively correlated with serum creatinine. Of note, urinary chemerin of patients with a fecal calprotectin > 500 µg/g was significantly higher compared to patients with lower calprotectin levels and compared to healthy controls. Serum creatinine did not differ between the patient groups. Conclusion: Urinary chemerin might present a novel non-invasive biomarker for monitoring IBD severity and clinical course.