Karolina Sulek

Microbiotas from UC patients display altered metabolism and reduced ability of LAB to colonize mucus

We compared fecal microbial communities derived either from Ulcerative Colitis (UC) patients in remission (n = 4) or in relapse (n = 4), or from healthy subjects (n = 4). These communities were used for inoculation of a dynamic in vitro gut model, which contained integrated mucin-covered microcosms. We found that the microbiota of the ‘mucus’ largely differed from that of the ‘lumen’. This was partly due to decreased mucus-associated populations of lactic acid producing bacterial populations (LAB), as LAB originating from UC patients had a significantly decreased capacity to colonize the mucin-covered microcosms as compared to those originating from healthy subjects. We found significant differences between the metabolomes of UC patients in relapse and remission, respectively, while the metabolome of patients in remission resembled that of healthy subjects. These novel findings constitute an important contribution to the understanding of the complex etiology of UC.

Hair Metabolomics: Identification of Fetal Compromise Provides Proof of Concept for Biomarker Discovery

Analysis of the human metabolome has yielded valuable insights into health, disease and toxicity. However, the metabolic profile of complex biological fluids such as blood is highly dynamic and this has limited the discovery of robust biomarkers. Hair grows relatively slowly, and both endogenous compounds and environmental exposures are incorporated from blood into hair during growth, which reflects the average chemical composition over several months. We used hair samples to study the metabolite profiles of women with pregnancies complicated by fetal growth restriction (FGR) and healthy matched controls. We report the use of GC-MS metabolite profiling of hair samples for biomarker discovery. Unsupervised statistical analysis showed complete discrimination of FGR from controls based on hair composition alone. A predictive model combining 5 metabolites produced an area under the receiver-operating curve of 0.998. This is the first study of the metabolome of human hair and demonstrates that this biological material contains robust biomarkers, which may lead to the development of a sensitive diagnostic tool for FGR, and perhaps more importantly, to stable biomarkers for a range of other diseases.

Maternal hair metabolome analysis identifies a potential marker of lipid peroxidation in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is defined as an abnormal glucose tolerance that develops, or is first recognized during pregnancy; the development of GDM markedly increases risks of adverse obstetric and perinatal outcome. The immediate consequences include an increased likelihood of a Caesarean section, hypoglycaemia of the newborn, respiratory distress syndrome, and macrosomia. Longer-term implications of a pregnancy affected by GDM include a substantially increased risk of the mother developing type 2 diabetes postnatally, as well as the offspring having an increased susceptibility to obesity and related metabolic complications in adulthood. Within the Asia–Pacific region there are an estimated 76 million women at risk of having a pregnancy complicated by diabetes, with recent estimates suggesting up to 18 % of pregnancies in China may be complicated by GDM [1]. Metabolomic profiling is a strategy for investigating the low weight molecules that represent the metabolome of a cell, tissue, or organism. The metabolome’s position as a downstream product of gene expression enables the provision of a high-resolution multifactorial phenotypic signature of disease aetiology, manifestation, or pathophysiology, and has led to the search for metabolite biomarkers. Previous studies have explored the GDMspecific metabolomic profile of blood samples, with promising results [2]. However, the dynamic nature of biofluids can be influenced by many transient factors such as recent dietary intake, and hormonal changes. Analysis of blood requires invasive sampling, immediate processing and curation of samples under controlled circumstances if analysis is not immediate. Hair, in contrast, is a highly stable structure retaining endogenous compounds and reflecting environmental exposures for many months; moreover, hair sampling is non-invasive and the storage and processing of hair is much simpler, making it a particularly useful source of biomarkers in low resource settings. We have previously demonstrated the potential of the hair metabolome by identifying a metabolomic signature able to predict the subsequent development of fetal growth restriction [3]. The current pilot study aimed to investigate the maternal hair metabolome in relation to GDM outcome, to determine if maternal hair could be a source of metabolic information underlying the development of GDM.

Sildenafil Therapy Normalizes the Aberrant Metabolomic Profile in the Comt-/- Mouse Model of Preeclampsia/Fetal Growth Restriction

Preeclampsia (PE) and fetal growth restriction (FGR) are serious complications of pregnancy, associated with greatly increased risk of maternal and perinatal morbidity and mortality. These complications are difficult to diagnose and no curative treatments are available. We hypothesized that the metabolomic signature of two models of disease, catechol-O-methyl transferase (COMT−/−) and endothelial nitric oxide synthase (Nos3−/−) knockout mice, would be significantly different from control C57BL/6J mice. Further, we hypothesised that any differences in COMT−/− mice would be resolved following treatment with Sildenafil, a treatment which rescues fetal growth. Targeted, quantitative comparisons of serum metabolic profiles of pregnant Nos3−/−, COMT−/− and C57BL/6J mice were made using a kit from BIOCRATES. Significant differences in 4 metabolites were observed between Nos3−/− and C57BL/6J mice (p < 0.05) and in 18 metabolites between C57BL/6J and COMT−/− mice (p < 0.05). Following treatment with Sildenafil, only 5 of the 18 previously identified differences in metabolites (p < 0.05) remained in COMT−/− mice. Metabolomic profiling of mouse models is possible, producing signatures that are clearly different from control animals. A potential new treatment, Sildenafil, is able to normalize the aberrant metabolomic profile in COMT−/− mice; as this treatment moves into clinical trials, this information may assist in assessing possible mechanisms of action.

Metabolite Profile of Cervicovaginal Fluids from Early Pregnancy Is Not Predictive of Spontaneous Preterm Birth

In our study, we used a mass spectrometry-based metabolomic approach to search for biomarkers that may act as early indicators of spontaneous preterm birth (sPTB). Samples were selected as a nested case-control study from the Screening for Pregnancy Endpoints (SCOPE) biobank in Auckland, New Zealand. Cervicovaginal swabs were collected at 20 weeks from women who were originally assessed as being at low risk of sPTB. Samples were analysed using gas chromatography-mass spectrometry (GC-MS). Despite the low amount of biomass (16–23 mg), 112 compounds were detected. Statistical analysis showed no significant correlations with sPTB. Comparison of reported infection and plasma inflammatory markers from early pregnancy showed two inflammatory markers were correlated with reported infection, but no correlation with any compounds in the metabolite profile was observed. We hypothesise that the lack of biomarkers of sPTB in the cervicovaginal fluid metabolome is simply because it lacks such markers in early pregnancy. We propose alternative biofluids be investigated for markers of sPTB. Our results lead us to call for greater scrutiny of previously published metabolomic data relating to biomarkers of sPTB in cervicovaginal fluids, as the use of small, high risk, or late pregnancy cohorts may identify metabolite biomarkers that are irrelevant for predicting risk in normal populations.

Metabolic footprint of Lactobacillus acidophilus NCFM at different pH

Lactobacillus acidophilus NCFM is a well known microorganism from the genomic and probiotic point of view. In order to analyze the potential interactions of NCFM with the surrounding environment, in vitro tests with the metabolic footprinting approach were performed. It was found that NCFM increased the concentration of lactic acid, succinic acid, adenine and arginine in the medium. The metabolism of NCFM did not change significantly between pH 5 and 7, suggesting that other environmental factors than pH might have bigger impact on its colonization throughout the gastrointestinal tract.

Lactobacillus acidophilus NCFM affects vitamin E acetate metabolism and intestinal bile acid signature in monocolonized mice.

Monocolonization of germ-free (GF) mice enables the study of specific bacterial species in vivo. Lactobacillus acidophilus NCFMTM (NCFM) is a probiotic strain; however, many of the mechanisms behind its health-promoting effect remain unknown. Here, we studied the effects of NCFM on the metabolome of jejunum, cecum, and colon of NCFM monocolonized (MC) and GF mice using liquid chromatography coupled to mass-spectrometry (LC-MS). The study adds to existing evidence that NCFM in vivo affects the bile acid signature of mice, in particular by deconjugation. Furthermore, we confirmed that carbohydrate metabolism is affected by NCFM in the mouse intestine as especially the digestion of oligosaccharides (penta- and tetrasaccharides) was increased in MC mice. Additionally, levels of α-tocopherol acetate (vitamin E acetate) were higher in the intestine of GF mice than in MC mice, suggesting that NCFM affects the vitamin E acetate metabolism. NCFM did not digest vitamin E acetate in vitro, suggesting that direct bacterial metabolism was not the cause of the altered metabolome in vivo. Taken together, our results suggest that NCFM affects intestinal carbohydrate metabolism, bile acid metabolism and vitamin E metabolism, although it remains to be investigated whether this effect is unique to NCFM.

Metabolomic profiling of maternal hair suggests rapid development of intrahepatic cholestasis of pregnancy

IntroductionIntrahepatic cholestasis of pregnancy (ICP) is a common maternal liver disease; development can result in devastating consequences, including sudden fetal death and stillbirth. Currently, recognition of ICP only occurs following onset of clinical symptoms.ObjectiveInvestigate the maternal hair metabolome for predictive biomarkers of ICP.MethodsThe maternal hair metabolome (gestational age of sampling between 17 and 41 weeks) of 38 Chinese women with ICP and 46 pregnant controls was analysed using gas chromatography–mass spectrometry.ResultsOf 105 metabolites detected in hair, none were significantly associated with ICP.ConclusionHair samples represent accumulative environmental exposure over time. Samples collected at the onset of ICP did not reveal any metabolic shifts, suggesting rapid development of the disease.