Comparative Studies of the Gut Microbiota in the Offspring of Mothers With and Without Gestational Diabetes.

Background: Offspring of mothers with gestational diabetes mellitus (GDM) have increased risk of developing metabolic disorders as they grow up. Microbial colonization of the newborn gut and environmental exposures affecting the configuration of the gut microbiota during infancy have been linked to increased risk of developing disease during childhood and adulthood. In a convenience sample, we examined whether the intestinal tract of children born to mothers with GDM is differentially colonized in early life compared to offspring of mothers with normal gestational glucose regulation. Secondly, we examined whether any such difference persists during infancy, thus potentially conferring increased risk of developing metabolic disease later in life. Methods: Fecal samples were collected from children of mothers with (n = 43) and without GDM (n = 82) during the first week of life and again at an average age of 9 months. The gut microbiota was characterized by 16S rRNA gene amplicon sequencing (V1-V2). Differences in diversity and composition according to maternal GDM status were assessed, addressing potential confounding by mode of delivery, perinatal antibiotics treatment, feeding and infant sex. Results: Children of mothers with GDM were featured by a differential composition of the gut microbiota, both during the first week of life and at 9 months, at higher taxonomic and OTU levels. Sixteen and 15 OTUs were differentially abundant after correction for multiple testing during the first week of life and at 9 months, respectively. Two OTUs remained differentially abundant after adjustment for potential confounders both during the first week of life and at 9 months. Richness (OTU) was decreased in neonates born to mothers with GDM; however, at 9 months no difference in richness was observed. There was no difference in Shannon's diversity or Pielou's evenness at any timepoint. Longitudinally, we detected differential changes in the gut microbiota composition from birth to infancy according to GDM status. Conclusion: Differences in glycaemic regulation in late pregnancy is linked with relatively modest variation in the gut microbiota composition of the offspring during the first week of life and 9 months after birth.

DNA methylation QTL analysis identifies new regulators of human longevity.

Human longevity is a complex trait influenced by both genetic and environmental factors, whose interaction is mediated by epigenetic mechanisms like DNA methylation. Here, we generated genome-wide whole-blood methylome data from 267 individuals, of which 71 were long-lived (90-104 years), by applying reduced representation bisulfite sequencing. We followed a stringent two-stage analysis procedure using discovery and replication samples to detect differentially methylated sites (DMSs) between young and long-lived study participants. Additionally, we performed a DNA methylation quantitative trait loci analysis to identify DMSs that underlie the longevity phenotype. We combined the DMSs results with gene expression data as an indicator of functional relevance. This approach yielded 21 new candidate genes, the majority of which are involved in neurophysiological processes or cancer. Notably, two candidates (PVRL2, ERCC1) are located on chromosome 19q, in close proximity to the well-known longevity- and Alzheimer's disease-associated loci APOE and TOMM40. We propose this region as a longevity hub, operating on both a genetic (APOE, TOMM40) and an epigenetic (PVRL2, ERCC1) level. We hypothesize that the heritable methylation and associated gene expression changes reported here are overall advantageous for the LLI and may prevent/postpone age-related diseases and facilitate survival into very old age.

Comparative analysis of amplicon and metagenomic sequencing methods reveals key features in the evolution of animal metaorganisms.

BACKGROUND: The interplay between hosts and their associated microbiome is now recognized as a fundamental basis of the ecology, evolution, and development of both players. These interdependencies inspired a new view of multicellular organisms as "metaorganisms." The goal of the Collaborative Research Center "Origin and Function of Metaorganisms" is to understand why and how microbial communities form long-term associations with hosts from diverse taxonomic groups, ranging from sponges to humans in addition to plants. METHODS: In order to optimize the choice of analysis procedures, which may differ according to the host organism and question at hand, we systematically compared the two main technical approaches for profiling microbial communities, 16S rRNA gene amplicon and metagenomic shotgun sequencing across our panel of ten host taxa. This includes two commonly used 16S rRNA gene regions and two amplification procedures, thus totaling five different microbial profiles per host sample. CONCLUSION: While 16S rRNA gene-based analyses are subject to much skepticism, we demonstrate that many aspects of bacterial community characterization are consistent across methods. The resulting insight facilitates the selection of appropriate methods across a wide range of host taxa. Overall, we recommend single- over multi-step amplification procedures, and although exceptions and trade-offs exist, the V3 V4 over the V1 V2 region of the 16S rRNA gene. Finally, by contrasting taxonomic and functional profiles and performing phylogenetic analysis, we provide important and novel insight into broad evolutionary patterns among metaorganisms, whereby the transition of animals from an aquatic to a terrestrial habitat marks a major event in the evolution of host-associated microbial composition.

Consistent alterations in faecal microbiomes of patients with primary sclerosing cholangitis independent of associated colitis.

BACKGROUND: Single-centre studies reported alterations of faecal microbiota in patients with primary sclerosing cholangitis (PSC). As regional factors may affect microbial communities, it is unclear if a microbial signature of PSC exists across different geographical regions. AIM: To identify a robust microbial signature of PSC independent of geography and environmental influences. METHODS: We included 388 individuals (median age, 47 years; range, 15-78) from Germany and Norway in the study, 137 patients with PSC (n = 75 with colitis), 118 with ulcerative colitis (UC) and 133 healthy controls. Faecal microbiomes were analysed by 16S rRNA gene sequencing (V1-V2). Differences in relative abundances of single taxa were subjected to a meta-analysis. RESULTS: In both cohorts, microbiota composition (beta-diversity) differed between PSC patients and controls (P < 0.001). Random forests classification discriminated PSC patients from controls in both geographical cohorts with an average area under the curve of 0.88. Compared to healthy controls, many new cohort-spanning alterations were identified in PSC, such as an increase of Proteobacteria and the bile-tolerant genus Parabacteroides, which were detected independent from geographical region. Associated colitis only had minor effects on microbiota composition, suggesting that PSC itself drives the faecal microbiota changes observed. CONCLUSION: Compared to healthy controls, numerous microbiota alterations are reproducible in PSC patients across geographical regions, clearly pointing towards a microbiota composition that is shaped by the disease itself and not by environmental factors. These reproducibly altered microbial populations might provide future insights into the pathophysiology of PSC.

Impaired Exocrine Pancreatic Function Associates With Changes in Intestinal Microbiota Composition and Diversity.

BACKGROUND & AIMS: Changes in intestinal microbiome composition are associated with inflammatory, metabolic, and malignant disorders. We studied how exocrine pancreatic function affects intestinal microbiota. METHODS: We performed 16S ribosomal RNA gene sequencing analysis of stool samples from 1795 volunteers from the population-based Study of Health in Pomerania who had no history of pancreatic disease. We also measured fecal pancreatic elastase by enzyme-linked immunosorbent assay and performed quantitative imaging of secretin-stimulated pancreatic fluid secretion. Associations of exocrine pancreatic function with microbial diversity or individual genera were calculated by permutational analysis of variance or linear regression, respectively. RESULTS: Differences in pancreatic elastase levels associated with significantly (P < .0001) greater changes in microbiota diversity than with participant age, body mass index, sex, smoking, alcohol consumption, or dietary factors. Significant changes in the abundance of 30 taxa, such as an increase in Prevotella (q < .0001) and a decrease of Bacteroides (q < .0001), indicated a shift from a type-1 to a type-2 enterotype. Changes in pancreatic fluid secretion alone were also associated with changes in microbial diversity (P = .0002), although to a lesser degree. CONCLUSIONS: In an analysis of fecal samples from 1795 volunteers, pancreatic acinar cell, rather than duct cell, function is presently the single most significant host factor to be associated with changes in intestinal microbiota composition.

Rhinovirus infections change DNA methylation and mRNA expression in children with asthma.

Human rhinovirus infection (HRVI) plays an important role in asthma exacerbations and is thought to be involved in asthma development during early childhood. We hypothesized that HRVI causes differential DNA methylation and subsequently differential mRNA expression in epithelial cells of children with asthma. Primary nasal epithelial cells from children with (n = 10) and without (n = 10) asthma were cultivated up to passage two and infected with Rhinovirus-16 (RV-16). HRVI-induced genome-wide differences of DNA methylation in asthmatics (vs. controls) and resulting mRNA expression were analyzed by the HumanMethylation450 BeadChip Kit (Illumina) and RNA sequencing. These results were further verified by pyrosequencing and quantitative PCR, respectively. 471 CpGs belonging to 268 genes were identified to have HRVI-induced asthma-specifically modified DNA methylation and mRNA expression. A minimum-change criteria was applied to restrict assessment of genes with changes in DNA methylation and mRNA expression of at least 3% and least 0.1 reads/kb per million mapped reads, respectively. Using this approach we identified 16 CpGs, including HLA-B-associated transcript 3 (BAT3) and Neuraminidase 1 (NEU1), involved in host immune response against HRVI. HRVI in nasal epithelial cells leads to specific modifications of DNA methylation with altered mRNA expression in children with asthma. The HRVI-induced alterations in DNA methylation occurred in genes involved in the host immune response against viral infections and asthma pathogenesis. The findings of our pilot study may partially explain how HRVI contribute to the persistence and progression of asthma, and aid to identify possible new therapeutic targets. The promising findings of this pilot study would benefit from replication in a larger cohort.

Gestational diabetes is associated with change in the gut microbiota composition in third trimester of pregnancy and postpartum.

BACKGROUND: Imbalances of gut microbiota composition are linked to a range of metabolic perturbations. In the present study, we examined the gut microbiota of women with gestational diabetes mellitus (GDM) and normoglycaemic pregnant women in late pregnancy and about 8 months postpartum. METHODS: Gut microbiota profiles of women with GDM (n = 50) and healthy (n = 157) pregnant women in the third trimester and 8 months postpartum were assessed by 16S rRNA gene amplicon sequencing of the V1-V2 region. Insulin and glucose homeostasis were evaluated by a 75 g 2-h oral glucose tolerance test during and after pregnancy. RESULTS: Gut microbiota of women with GDM was aberrant at multiple levels, including phylum and genus levels, compared with normoglycaemic pregnant women. Actinobacteria at phylum level and Collinsella, Rothia and Desulfovibrio at genus level had a higher abundance in the GDM cohort. Difference in abundance of 17 species-level operational taxonomic units (OTUs) during pregnancy was associated with GDM. After adjustment for pre-pregnancy body mass index (BMI), 5 of the 17 OTUs showed differential abundance in the GDM cohort compared with the normoglycaemic pregnant women with enrichment of species annotated to Faecalibacterium and Anaerotruncus and depletion of species annotated to Clostridium (sensu stricto) and to Veillonella. OTUs assigned to Akkermansia were associated with lower insulin sensitivity while Christensenella OTUs were associated with higher fasting plasma glucose concentration. OTU richness and Shannon index decreased from late pregnancy to postpartum regardless of metabolic status. About 8 months after delivery, the microbiota of women with previous GDM was still characterised by an aberrant composition. Thirteen OTUs were differentially abundant in women with previous GDM compared with women with previous normoglycaemic pregnancy. CONCLUSION: GDM diagnosed in the third trimester of pregnancy is associated with a disrupted gut microbiota composition compared with normoglycaemic pregnant women, and 8 months after pregnancy, differences in the gut microbiota signatures are still detectable. The gut microbiota composition of women with GDM, both during and after pregnancy, resembles the aberrant microbiota composition reported in non-pregnant individuals with type 2 diabetes and associated intermediary metabolic traits.

The antibiotic resistome and microbiota landscape of refugees from Syria, Iraq and Afghanistan in Germany.

BACKGROUND: Multidrug-resistant bacteria represent a substantial global burden for human health, potentially fuelled by migration waves: in 2015, 476,649 refugees applied for asylum in Germany mostly as a result of the Syrian crisis. In Arabic countries, multiresistant bacteria cause significant problems for healthcare systems. Currently, no data exist describing antibiotic resistances in healthy refugees. Here, we assess the microbial landscape and presence of antibiotic resistance genes (ARGs) in refugees and German controls. To achieve this, a systematic study was conducted in 500 consecutive refugees, mainly from Syria, Iraq, and Afghanistan and 100 German controls. Stool samples were subjected to PCR-based quantification of 42 most relevant ARGs, 16S ribosomal RNA gene sequencing-based microbiota analysis, and culture-based validation of multidrug-resistant microorganisms. RESULTS: The fecal microbiota of refugees is substantially different from that of resident Germans. Three categories of resistance profiles were found: (i) ARGs independent of geographic origin of individuals comprising BIL/LAT/CMA, ErmB, and mefE; (ii) vanB with a high prevalence in Germany; and (iii) ARGs showing substantially increased prevalences in refugees comprising CTX-M group 1, SHV, vanC1, OXA-1, and QnrB. The majority of refugees carried five or more ARGs while the majority of German controls carried three or less ARGs, although the observed ARGs occurred independent of signatures of potential pathogens. CONCLUSIONS: Our results, for the first time, assess antibiotic resistance genes in refugees and demonstrate a substantially increased prevalence for most resistances compared to German controls. The antibiotic resistome in refugees may thus require particular attention in the healthcare system of host countries.

NGS-based methylation profiling differentiates TCF3-HLF and TCF3-PBX1 positive B-cell acute lymphoblastic leukemia.

AIM: To determine whether methylation differences between mostly fatal TCF3-HLF and curable TCF3-PBX1 pediatric acute lymphoblastic leukemia subtypes can be associated with differential gene expression and remission. MATERIALS & METHODS: Five (extremely rare) TCF3-HLF versus five (very similar) TCF3-PBX1 patients were sampled before and after remission and analyzed using reduced representation bisulfite sequencing and RNA-sequencing. RESULTS: We identified 7000 differentially methylated CpG sites between subtypes, of which 78% had lower methylation levels in TCF3-HLF. Gene expression was negatively correlated with CpG sites in 23 genes. KBTBD11 clearly differed in methylation and expression between subtypes and before and after remission in TCF3-HLF samples. CONCLUSION: KBTBD11 hypomethylation may be a promising potential target for further experimental validation especially for the TCF3-HLF subtype.

Application of the distance-based F test in an mGWAS investigating ß diversity of intestinal microbiota identifies variants in SLC9A8 (NHE8) and 3 other loci.

Factors shaping the human intestinal microbiota range from environmental influences, like smoking and exercise, over dietary patterns and disease to the host's genetic variation. Recently, we could show in a microbiome genome-wide association study (mGWAS) targeting genetic variation influencing the ß diversity of gut microbial communities, that approximately 10% of the overall gut microbiome variation can be explained by host genetics. Here, we report on the application of a new method for genotype-ß-diversity association testing, the distance-based F (DBF) test. With this we identified 4 loci with genome-wide significant associations, harboring the genes CBEP4, SLC9A8, TNFSF4, and SP140, respectively. Our findings highlight the utility of the high-performance DBF test in ß diversity GWAS and emphasize the important role of host genetics and immunity in shaping the human intestinal microbiota.

Functional variants in the sucrase-isomaltase gene associate with increased risk of irritable bowel syndrome.

OBJECTIVE: IBS is a common gut disorder of uncertain pathogenesis. Among other factors, genetics and certain foods are proposed to contribute. Congenital sucrase-isomaltase deficiency (CSID) is a rare genetic form of disaccharide malabsorption characterised by diarrhoea, abdominal pain and bloating, which are features common to IBS. We tested sucrase-isomaltase (SI) gene variants for their potential relevance in IBS. DESIGN: We sequenced SI exons in seven familial cases, and screened four CSID mutations (p.Val557Gly, p.Gly1073Asp, p.Arg1124Ter and p.Phe1745Cys) and a common SI coding polymorphism (p.Val15Phe) in a multicentre cohort of 1887 cases and controls. We studied the effect of the 15Val to 15Phe substitution on SI function in vitro. We analysed p.Val15Phe genotype in relation to IBS status, stool frequency and faecal microbiota composition in 250 individuals from the general population. RESULTS: CSID mutations were more common in patients than asymptomatic controls (p=0.074; OR=1.84) and Exome Aggregation Consortium reference sequenced individuals (p=0.020; OR=1.57). 15Phe was detected in 6/7 sequenced familial cases, and increased IBS risk in case-control and population-based cohorts, with best evidence for diarrhoea phenotypes (combined p=0.00012; OR=1.36). In the population-based sample, 15Phe allele dosage correlated with stool frequency (p=0.026) and Parabacteroides faecal microbiota abundance (p=0.0024). The SI protein with 15Phe exhibited 35% reduced enzymatic activity in vitro compared with 15Val (p<0.05). CONCLUSIONS: SI gene variants coding for disaccharidases with defective or reduced enzymatic activity predispose to IBS. This may help the identification of individuals at risk, and contribute to personalising treatment options in a subset of patients.

Functional sequencing read annotation for high precision microbiome analysis.

The vast majority of microorganisms on Earth reside in often-inseparable environment-specific communities-microbiomes. Meta-genomic/-transcriptomic sequencing could reveal the otherwise inaccessible functionality of microbiomes. However, existing analytical approaches focus on attributing sequencing reads to known genes/genomes, often failing to make maximal use of available data. We created faser (functional annotation of sequencing reads), an algorithm that is optimized to map reads to molecular functions encoded by the read-correspondent genes. The mi-faser microbiome analysis pipeline, combining faser with our manually curated reference database of protein functions, accurately annotates microbiome molecular functionality. mi-faser's minutes-per-microbiome processing speed is significantly faster than that of other methods, allowing for large scale comparisons. Microbiome function vectors can be compared between different conditions to highlight environment-specific and/or time-dependent changes in functionality. Here, we identified previously unseen oil degradation-specific functions in BP oil-spill data, as well as functional signatures of individual-specific gut microbiome responses to a dietary intervention in children with Prader-Willi syndrome. Our method also revealed variability in Crohn's Disease patient microbiomes and clearly distinguished them from those of related healthy individuals. Our analysis highlighted the microbiome role in CD pathogenicity, demonstrating enrichment of patient microbiomes in functions that promote inflammation and that help bacteria survive it.

Targeted Microbiome Intervention by Microencapsulated Delayed-Release Niacin Beneficially Affects Insulin Sensitivity in Humans.

OBJECTIVE: Gut microbiota represent a potential novel target for future prediabetes and type 2 diabetes therapies. In that respect, niacin has been shown to beneficially affect the host-microbiome interaction in rodent models. RESEARCH DESIGN AND METHODS: We characterized more than 500 human subjects with different metabolic phenotypes regarding their niacin (nicotinic acid [NA] and nicotinamide [NAM]) status and their gut microbiome. In addition, NA and NAM delayed-release microcapsules were engineered and examined in vitro and in vivo in two human intervention studies (bioavailability study and proof-of-concept/safety study). RESULTS: We found a reduced α-diversity and Bacteroidetes abundance in the microbiome of obese human subjects associated with a low dietary niacin intake. We therefore developed delayed-release microcapsules targeting the ileocolonic region to deliver increasing amounts of NA and NAM to the microbiome while preventing systemic resorption to avoid negative side effects (e.g., facial flushing). In vitro studies on these delayed-release microcapsules revealed stable conditions at pH 1.4, 4.5, and 6.8, followed by release of the compounds at pH 7.4, simulating the ileocolonic region. In humans in vivo, gut-targeted delayed-release NA but not NAM produced a significant increase in the abundance of Bacteroidetes. In the absence of systemic side effects, these favorable microbiome changes induced by microencapsulated delayed-release NA were associated with an improvement of biomarkers for systemic insulin sensitivity and metabolic inflammation. CONCLUSION: Targeted microbiome intervention by delayed-release NA might represent a future therapeutic option for prediabetes and type 2 diabetes.

Formula Feeding Predisposes Neonatal Piglets to Clostridium difficile Gut Infection.

Spontaneous outbreaks of Clostridium difficile infection (CDI) occur in neonatal piglets, but the predisposing factors are largely not known. To study the conditions for C. difficile colonization and CDI development, 48 neonatal piglets were moved into isolators, fed bovine milk-based formula, and infected with C. difficile 078. Analyses included clinical scoring; measurement of the fecal C. difficile burden, toxin B level, and calprotectin level; and postmortem histopathological analysis of colon specimens. Controls were noninfected suckling piglets. Fecal specimens from suckling piglets, formula-fed piglets, and formula-fed, C. difficile-infected piglets were used for metagenomics analysis. High background levels of C. difficile and toxin were detected in formula-fed piglets prior to infection, while suckling piglets carried about 3-fold less C. difficile, and toxin was not detected. Toxin level in C. difficile-challenged animals correlated positively with C. difficile and calprotectin levels. Postmortem signs of CDI were absent in suckling piglets, whereas mesocolonic edema and gas-filled distal small intestines and ceca, cellular damage, and reduced expression of claudins were associated with animals from the challenge trials. Microbiota in formula-fed piglets was enriched with Escherichia, Shigella, Streptococcus, Enterococcus, and Ruminococcus species. Formula-fed piglets were predisposed to C. difficile colonization earlier as compared to suckling piglets. Infection with a hypervirulent C. difficile ribotype did not aggravate the symptoms of infection. Sow-offspring association and consumption of porcine milk during early life may be crucial for the control of C. difficile expansion in piglets.

Heart failure is associated with depletion of core intestinal microbiota.

AIMS: In spite of current medical treatment approaches, mortality of chronic heart failure (HF) remains high and novel treatment modalities are thus urgently needed. A recent theory proposes a possible impact of the intestinal microbiome on the incidence and clinical course of heart failure. This study sought to systematically investigate, if there are specific changes of the intestinal microbiome in heart failure patients. METHODS AND RESULTS: The intestinal microbiome of 20 patients with heart failure with reduced ejection fraction due to ischemic or dilated cardiomyopathy was investigated by applying high-throughput sequencing of the bacterial 16S rRNA gene. Microbial profiles were compared to those of matched controls in which heart failure was ruled out by clinical assessment and NT-proBNP serum levels (n = 20). According to the Shannon diversity index (which measures the intra-individual alpha-diversity) based on the distribution of operational taxonomic units (OTUs), HF cases showed a nominally significantly lower diversity index compared to controls (Pnom. = 0.01), and testing for genera abundance showed a tendency towards a decreased alpha diversity of HF patients. Beta-diversity measures (inter-individual diversity) revealed a highly significant separation of HF cases and controls, (e.g. Pweighted UniFracv = 0.004). Assessing the individual abundance of core measurable microbiota (CMM), a significant decrease of Coriobacteriaceae, Erysipelotrichaceae and Ruminococcaceae was observed on the family level. In line with that, Blautia, Collinsella, uncl. Erysipelotrichaceae and uncl. Ruminococcaceae showed a significant decrease in HF cases compared to controls on the genus level. CONCLUSIONS: Heart failure patients showed a significantly decreased diversity of the intestinal microbiome as well as a downregulation of key intestinal bacterial groups. Our data point to an altered intestinal microbiome as a potential player in the pathogenesis and progression of heart failure.

Cold-induced conversion of cholesterol to bile acids in mice shapes the gut microbiome and promotes adaptive thermogenesis.

Adaptive thermogenesis is an energy-demanding process that is mediated by cold-activated beige and brown adipocytes, and it entails increased uptake of carbohydrates, as well as lipoprotein-derived triglycerides and cholesterol, into these thermogenic cells. Here we report that cold exposure in mice triggers a metabolic program that orchestrates lipoprotein processing in brown adipose tissue (BAT) and hepatic conversion of cholesterol to bile acids via the alternative synthesis pathway. This process is dependent on hepatic induction of cytochrome P450, family 7, subfamily b, polypeptide 1 (CYP7B1) and results in increased plasma levels, as well as fecal excretion, of bile acids that is accompanied by distinct changes in gut microbiota and increased heat production. Genetic and pharmacological interventions that targeted the synthesis and biliary excretion of bile acids prevented the rise in fecal bile acid excretion, changed the bacterial composition of the gut and modulated thermogenic responses. These results identify bile acids as important metabolic effectors under conditions of sustained BAT activation and highlight the relevance of cholesterol metabolism by the host for diet-induced changes of the gut microbiota and energy metabolism.

Hypothalamic Inflammation in Human Obesity Is Mediated by Environmental and Genetic Factors.

Obesity is associated with hypothalamic inflammation (HI) in animal models. In the current study, we examined the mediobasal hypothalamus (MBH) of 57 obese human subjects and 54 age- and sex- matched nonobese control subjects by MRI and analyzed the T2 hyperintensity as a measure of HI. Obese subjects exhibited T2 hyperintensity in the left but not the right MBH, which was strongly associated with systemic low-grade inflammation. MRS revealed the number of neurons in the left hypothalamic region to be similar in obese versus control subjects, suggesting functional but not structural impairment due to the inflammatory process. To gain mechanistic insights, we performed nutritional analysis and 16S rDNA microbiome sequencing, which showed that high-fat diet induces reduction of Parasutterella sp. in the gut, which is significantly correlated with MBH T2 hyperintensity. In addition to these environmental factors, we found subjects carrying common polymorphisms in the JNK or the MC4R gene to be more susceptible to HI. Finally, in a subgroup analysis, bariatric surgery had no effect on MBH T2 hyperintensity despite inducing significant weight loss and improvement of peripheral insulin sensitivity. In conclusion, obesity in humans is associated with HI and disturbances in the gut-brain axis, which are influenced by both environmental and genetic factors.

Interdisciplinary approach towards a systems medicine toolbox using the example of inflammatory diseases.

Electronic access to multiple data types, from generic information on biological systems at different functional and cellular levels to high-throughput molecular data from human patients, is a prerequisite of successful systems medicine research. However, scientists often encounter technical and conceptual difficulties that forestall the efficient and effective use of these resources. We summarize and discuss some of these obstacles, and suggest ways to avoid or evade them.The methodological gap between data capturing and data analysis is huge in human medical research. Primary data producers often do not fully apprehend the scientific value of their data, whereas data analysts maybe ignorant of the circumstances under which the data were collected. Therefore, the provision of easy-to-use data access tools not only helps to improve data quality on the part of the data producers but also is likely to foster an informed dialogue with the data analysts.We propose a means to integrate phenotypic data, questionnaire data and microbiome data with a user-friendly Systems Medicine toolbox embedded into i2b2/tranSMART. Our approach is exemplified by the integration of a basic outlier detection tool and a more advanced microbiome analysis (alpha diversity) script. Continuous discussion with clinicians, data managers, biostatisticians and systems medicine experts should serve to enrich even further the functionality of toolboxes like ours, being geared to be used by 'informed non-experts' but at the same time attuned to existing, more sophisticated analysis tools.