Navigating through metaproteomics data: a logbook of database searching.

Metaproteomic research involves various computational challenges during the identification of fragmentation spectra acquired from the proteome of a complex microbiome. These issues are manifold and range from the construction of customized sequence databases, the optimal setting of search parameters to limitations in the identification search algorithms themselves. In order to assess the importance of these individual factors, we studied the effect of strategies to combine different search algorithms, explored the influence of chosen database search settings, and investigated the impact of the size of the protein sequence database used for identification. Furthermore, we applied de novo sequencing as a complementary approach to classic database searching. All evaluations were performed on a human intestinal metaproteome dataset. Pyrococcus furiosus proteome data were used to contrast database searching of metaproteomic data to a classic proteomic experiment. Searching against subsets of metaproteome databases and the use of multiple search engines increased the number of identifications. The integration of P. furiosus sequences in a metaproteomic sequence database showcased the limitation of the target-decoy-controlled false discovery rate approach in combination with large sequence databases. The selection of varying search engine parameters and the application of de novo sequencing represented useful methods to increase the reliability of the results. Based on our findings, we provide recommendations for the data analysis that help researchers to establish or improve analysis workflows in metaproteomics.

Colonic metaproteomic signatures of active bacteria and the host in obesity.

Obesity is associated with the intestinal microbiota in humans but the underlying mechanisms are yet to be fully understood. Our previous phylogenetic study showed that the faecal microbiota profiles of nonobese versus obese and morbidly obese individuals differed. Here, we have extended this analysis with a characterization of the faecal metaproteome, in order to detect differences at a functional level. Proteins were extracted from crude faecal samples of 29 subjects, separated by 1D gel electrophoresis and characterized using RP LC-MS/MS. The peptide data were analyzed in database searches with two complementary algorithms, OMSSA and X!Tandem, to increase the number of identifications. Evolutionary genealogy of genes: nonsupervised orthologous groups (EggNOG) database searches resulted in the functional annotation of over 90% of the identified microbial and human proteins. Based on both bacterial and human proteins, a clear clustering of obese and nonobese samples was obtained that exceeded the phylogenetic separation in dimension. Moreover, integration of the metaproteomics and phylogenetic datasets revealed notably that the phylum Bacteroidetes was metabolically more active in the obese than nonobese subjects. Finally, significant correlations between clinical measurements and bacterial gene functions were identified. This study emphasizes the importance of integrating data of the host and microbiota to understand their interactions.

TP53 Y220C Is a Hotspot Mutation in Oropharyngeal Squamous Cell Carcinoma.

OBJECTIVES: Although TP53 mutations in head and neck squamous cell carcinoma (HNSCC) have been extensively studied, their association with the different subsites in the head and neck region has never been described. METHODS: Sanger sequence analysis evaluating exons 4-9 in the TP53 gene was performed on 116 HNSCC patients. The exon location, exact codon and corresponding substitution in relation to the anatomical site (subsite) of the HNSCC were evaluated. RESULTS: We found nonsynonymous TP53 mutations in 70% (81/116) of the patients. In oral cavity carcinomas, most mutations occurred in exon 7 (37%). In oropharyngeal and laryngeal tumors, mutations were mainly found in exons 6 and 7. The most common mutation was located in codon 220, and all of these were an Y220C mutation. Five out of nine (56%) Y220C mutations occurred in oropharyngeal tumors. Additionally, 22% of all mutations observed in oropharyngeal squamous cell carcinoma (OPSCC) consisted of Y220C mutations. CONCLUSION: In this study, the subsite-related distribution of TP53 mutations underlines the biological diversity between tumors arising from different anatomical regions in the head and neck region. Moreover, the Y220C mutation was by far the most prevalent TP53 mutation in HNSCC and a relative hotspot mutation in the oropharynx. © 2015 S. Karger AG, Basel.

Non-alcoholic steatohepatitis: a non-invasive diagnosis by analysis of exhaled breath.

BACKGROUND & AIMS: Histological evaluation of a liver biopsy is the current gold standard to diagnose non-alcoholic steatohepatitis (NASH), but the procedure to obtain biopsies is associated with morbidity and high costs. Hence, only subjects at high risk are biopsied, leading to underestimation of NASH prevalence, and undertreatment. Since analysis of volatile organic compounds in breath has been shown to accurately identify subjects with other chronic inflammatory diseases, we investigated its potential as a non-invasive tool to diagnose NASH. METHODS: Wedge-shaped liver biopsies from 65 subjects (BMI 24.8-64.3 kg/m(2)) were obtained during surgery and histologically evaluated. The profile of volatile organic compounds in pre-operative breath samples was analyzed by gas chromatography-mass spectrometry and related to liver histology scores and plasma parameters of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). RESULTS: Three exhaled compounds were sufficient to distinguish subjects with (n=39) and without NASH (n=26), with an area under the ROC curve of 0.77. The negative and positive predictive values were 82% and 81%. In contrast, elevated ALT levels or increased AST/ALT ratios both showed negative predictive values of 43%, and positive predictive values of 88% and 70%, respectively. The breath test reduced the hypothetical percentage of undiagnosed NASH patients from 67-79% to 10%, and of misdiagnosed subjects from 49-51% to 18%. CONCLUSIONS: Analysis of volatile organic compounds in exhaled air is a promising method to indicate NASH presence and absence. In comparison to plasma transaminase levels, the breath test significantly reduced the percentage of missed NASH patients and the number of unnecessarily biopsied subjects.

Reduced Paneth cell antimicrobial protein levels correlate with activation of the unfolded protein response in the gut of obese individuals.

The intestinal microbiota is increasingly acknowledged to play a crucial role in the development of obesity. A shift in intestinal microbiota composition favouring the presence of Firmicutes over Bacteroidetes has been observed in obese subjects. A similar shift has been reported in mice with deficiency of active Paneth cell α-defensins. We aimed at investigating changes in Paneth cell antimicrobial levels in the gut of obese subjects. Next, we studied activation of the unfolded protein response (UPR) as a possible mechanism involved in altered Paneth cell function. Paneth cell numbers were counted in jejunal sections of 15 severely obese (BMI > 35) and 15 normal weight subjects. Expression of Paneth cell antimicrobials human α-defensin 5 (HD5) and lysozyme were investigated using immunohistochemistry, qPCR, and western blot. Activation of the UPR was assessed with western blot. Severely obese subjects showed decreased protein levels of both HD5 and lysozyme, while Paneth cell numbers were unchanged. Lysozyme protein levels correlated inversely with BMI. Increased expression of HD5 (DEFA5) and lysozyme (LYZ) transcripts in the intestine of obese subjects prompted us to investigate a possible translational block caused by UPR activation. Binding protein (BiP) and activating transcription factor 4 (ATF4) levels were increased, confirming activation of the UPR in the gut of obese subjects. Furthermore, levels of both proteins correlated with BMI. Involvement of the UPR in the lowered antimicrobial protein levels in obese subjects was strongly suggested by a negative correlation between BiP levels and lysozyme levels. Additionally, indications of ER stress were apparent in Paneth cells of obese subjects. Our findings provide the first evidence for altered Paneth cell function in obesity, which may have important implications for the obesity-associated shift in microbiota composition. In addition, we show activation of the UPR in the intestine of obese subjects, which may underlie the observed Paneth cell compromise.

Decreased nucleotide excision repair in steatotic livers associates with myeloperoxidase-immunoreactivity.

Chronic inflammation is characterized by the influx of neutrophils and is associated with an increased production of reactive oxygen species that can damage DNA. Oxidative DNA damage is generally thought to be involved in the increased risk of cancer in inflamed tissues. We previously demonstrated that activated neutrophil mediated oxidative stress results in a reduction in nucleotide excision repair (NER) capacity, which could further enhance mutagenesis. Inflammation and oxidative stress are critical factors in the progression of nonalcoholic fatty liver disease that is linked with enhanced liver cancer risk. In this report, we therefore evaluated the role of neutrophils and the associated oxidative stress in damage recognition and DNA repair in steatotic livers of 35 severely obese subjects with either nonalcoholic steatohepatitis (NASH) (n=17) or steatosis alone (n=18). The neutrophilic influx in liver was assessed by myeloperoxidase (MPO) staining and the amount of oxidative DNA damage by measuring M(1)dG adducts. No differences in M(1)dG adduct levels were observed between patients with or without NASH and also not between individuals with high or low MPO immunoreactivity. However, we found that high expression of MPO in the liver, irrespective of disease status, reduced the damage recognition capacity as determined by staining for histone 2AX phosphorylation (γH2AX). This reduction in γH2AX formation in individuals with high MPO immunoreactivity was paralleled by a significant decrease in NER capacity as assessed by a functional repair assay, and was not related to cell proliferation. Thus, the observed reduction in NER capacity upon hepatic inflammation is associated with and may be a consequence of reduced damage recognition. These findings suggest a novel mechanism of liver cancer development in patients with nonalcoholic fatty liver disease.

Novel evidence for chronic exposure to endotoxin in human nonalcoholic steatohepatitis.

BACKGROUND: Endotoxin is hypothesized to play an important role in the activation of inflammatory pathways associated with nonalcoholic steatohepatitis (NASH). However, demonstration of hepatic endotoxin exposure is challenging due to the inaccessibility of the portal circulation. Furthermore, reliable measurement of the relatively low endotoxin levels in plasma of patients with liver disease and subsequent interpretation remain difficult. GOALS: In this study, we used the EndoCab assay that measures endogenous antibodies to the core region of endotoxin to estimate hepatic endotoxin exposure over time. STUDY: IgG levels against endotoxin were measured in peripheral plasma obtained from 21 severely obese patients with NASH and 9 severely obese patients with healthy livers. RESULTS: Plasma IgG levels against endotoxin were significantly elevated in patients with NASH compared with patients with healthy livers (48±63 GMU/mL vs. 10±13 GMU/mL). Moreover, these IgG levels progressively increased with NASH grade (grade 1 29±37; grade 2 58±51; grade 3 84±132 GMU/mL, P<0.05). There was no relation between plasma IgG levels and NASH stage. CONCLUSIONS: Plasma IgG levels against endotoxin were found to be increased in biopsy-proven human NASH and increased with aggravated inflammation in NASH, suggesting a relationship between chronic endotoxin exposure and the severity of human NASH.

Delayed primary closure of the septic open abdomen with a dynamic closure system.

BACKGROUND: The major challenge in the management of patients with an infected open abdomen (OA) is to control septic peritonitis and intra-abdominal fluid secretion, and to facilitate repeated abdominal exploration, while preserving the fascia for delayed primary closure. We here present a novel method for closure of the infected OA, based on continuous dynamic tension, in order to achieve re-approximation of the fascial edges of the abdominal wall. METHODS: Eighteen cases with severe peritonitis of various origin (e.g., gastrointestinal perforations, anastomotic leakage) were primarily stabilized by laparostomy, sealed with either the vacuum-assisted closure abdominal dressing or the Bogotá bag. After hemodynamic stabilization and control of the sepsis, the Abdominal Re-approximation Anchor System (ABRA; Canica Design, Almonte, Ontario, Canada) was applied. This system approximates the wound margins through dynamic traction exerted by transfascial elastomers. Before ABRA application, 5/18 patients had a grade 2B, 2/18 a grade 3, and 11/18 a grade or 4 status according to the open abdomen classification of Björck. RESULTS: In this severely ill population the mean time before ABRA system application was 12 days (range: 2-39 days). Two of 18 patients died of non-ABRA-related causes within three weeks. In 14 of the remaining 16 patients (88%) primary abdominal closure of the midline was accomplished in 15 days (range: 7-30 days). The other two patients needed a component separation technique according to Ramirez to reach closure. However, secondary wound dehiscence occurred in both these patients. Two thirds of patients (12/18) developed pressure sores to the skin and/or dermis, but all healed without further complications. During outpatient clinic follow-up, 4/14 successfully closed patients still developed a midline hernia. CONCLUSIONS: Delayed primary closure of OA in septic patients could be achieved in 88% with this new approximation system. However, the risk of hernia development remained. We consider this system a useful tool in the treatment of septic patients with an open abdomen.

Thyroid Cartilage Cysts, A Rare Entity Causing Dysphonia.

Five cases are presented with a strained voice quality due to a unique underlying cause: thyroid cartilage cysts. Laryngoscopy and radiological images show antero-medial displacement of both vestibular and vocal fold(s). Swelling in the ala of the thyroid cartilage results in a pear-shaped lumen. These cysts were marsupialized with CO2 laser, fluid emerged, and histological biopsies confirmed cartilaginous cysts. Postoperatively, all cases report largely reduced or completely resolved vocal complaints, with a consistent follow-up of 2 years. Together with previous publications, an overview of 17 cases is presented, to enhance awareness that thyroid cartilage cysts can cause a strained voice quality. Laryngoscope, 130:E628-E631, 2020.

The outcome of the axillofemoral bypass: a retrospective analysis of 45 patients.

PURPOSE: This study was designed to retrospectively analyze outcomes of axillofemoral bypass (AxFB) operations performed in patients with severe comorbidities. METHODS: All patients (n = 45) who received an AxFB between 1990 and 2005 for aortoiliac occlusive disease (AIOD, n = 35) or infectious aortic disease (IAD, n = 10) were included. Information on patency of the bypass and mortality was retrieved from patient records. A Kaplan-Meier survival analysis was performed to illustrate survival rates, limb salvage, and primary and secondary patency. RESULTS: Included patients had several comorbidities and a high operative risk. In this group, a 30-day mortality rate of 20% was found: 17% for the AIOD group, and 30% for the IAD group. During 5-year follow-up 20 patients died, of which 15 during the first year after operation. Survival rates were at 64 and 41% at 1 and 5 years and limb salvage rates were 84% for both these years. Primary patency rates at 1 and 5 years were 72 and 58%, respectively, and secondary patency rates were 86% at both time points. CONCLUSIONS: High mortality rates were found in AIOD or IAD patients who received an AxFB. However, for high-risk patients with an already reduced life expectancy, the AxFB remains an alternative with acceptable patency rates.

Impact of Duodenal-Jejunal Exclusion on Satiety Hormones.

OBJECTIVE: Bariatric procedures that exclude the proximal small intestine lead to significant weight loss which is probably mediated by changes in hormones that alter appetite, such as peptide YY (PYY), ghrelin, cholecystokinin (CCK), and leptin. Here, the effect of the non-surgical duodenal-jejunal bypass liner (DJBL) on concentrations of hormones implicated in appetite control was investigated. SUBJECTS: A two-center prospective study was conducted between January and December 2010. Seventeen obese subjects with type 2 diabetes were treated with the DJBL for 24 weeks. Fasting concentrations of leptin and meal responses of plasma PYY, CCK, and ghrelin were determined prior to and after implantation of the DJBL. RESULTS: At baseline, subjects had an average body weight of 116.0 ± 5.8 kg. One week after implantation, subjects had lost 4.3 ± 0.6 kg (p < 0.01), which progressed to 12.7 ± 1.3 kg at week 24 (p < 0.01). Postprandial concentrations of PYY and ghrelin increased (baseline vs. week 1 vs. week 24 PYY: 2.6 ± 0.2 vs. 4.1 ± 0.4 vs. 4.1 ± 0.7 nmol/L/min and ghrelin: 7.8 ± 1.8 vs. 11.0 ± 1.8 vs. 10.6 ± 1.8 ng/mL/min, all p < 0.05). In parallel, the CCK response decreased (baseline vs. week 1 vs. week 24: 434 ± 51 vs. 229 ± 52 vs. 256 ± 51 pmol/L/min, p < 0.01). Fasting leptin concentrations also decreased (baseline vs. week 24: 98 ± 17 vs. 53 ± 10 ng/mL, p < 0.01). CONCLUSIONS: DJBL treatment induces weight loss paralleled by changes in concentrations of hormones involved in appetite control.

Bariatric surgery in morbidly obese adolescents: a systematic review and meta-analysis.

Pubmed, Embase, and Cochrane were systematically reviewed for available evidence on bariatric surgery in adolescents. Thirty-seven included studies evaluated the effect of laparoscopic adjustable gastric banding (LAGB), Roux-en-Y gastric bypass (RYGB), or laparoscopic sleeve gastrectomy (LSG) in patients ≤18 years old. Fifteen of 37 studies were prospective, including one RCT. Mean body mass index (BMI) loss after LAGB was 11.6 kg/m(2) (95% CI 9.8-13.4), versus 16.6 kg/m(2) (95% CI 13.4-19.8) after RYGB and 14.1 kg/m(2) (95% CI 10.8-17.5) after LSG. Two unrelated deaths were reported after 495 RYGB procedures. All three bariatric procedures result in substantial weight loss and improvement of comorbidity with an acceptable complication rate, indicating that surgical intervention is applicable in appropriately selected morbidly obese adolescents.

Complement alternative pathway activation in human nonalcoholic steatohepatitis.

The innate immune system plays a major role in the pathogenesis of nonalcoholic steatohepatitis (NASH). Recently we reported complement activation in human NASH. However, it remained unclear whether the alternative pathway of complement, which amplifies C3 activation and which is frequently associated with pathological complement activation leading to disease, was involved. Here, alternative pathway components were investigated in liver biopsies of obese subjects with healthy livers (n = 10) or with NASH (n = 12) using quantitative PCR, Western blotting, and immunofluorescence staining. Properdin accumulated in areas where neutrophils surrounded steatotic hepatocytes, and colocalized with the C3 activation product C3c. C3 activation status as expressed by the C3c/native C3 ratio was 2.6-fold higher (p<0.01) in subjects with NASH despite reduced native C3 concentrations (0.94±0.12 vs. 0.57±0.09; p<0.01). Hepatic properdin levels positively correlated with levels of C3c (rs = 0.69; p<0.05) and C3c/C3 activation ratio (rs = 0.59; p<0.05). C3c, C3 activation status (C3c/C3 ratio) and properdin levels increased with higher lobular inflammation scores as determined according to the Kleiner classification (C3c: p<0.01, C3c/C3 ratio: p<0.05, properdin: p<0.05). Hepatic mRNA expression of factor B and factor D did not differ between subjects with healthy livers and subjects with NASH (factor B: 1.00±0.19 vs. 0.71±0.07, p = 0.26; factor D: 1.00±0.21 vs. 0.66±0.14, p = 0.29;). Hepatic mRNA and protein levels of Decay Accelerating Factor tended to be increased in subjects with NASH (mRNA: 1.00±0.14 vs. 2.37±0.72; p = 0.22; protein: 0.51±0.11 vs. 1.97±0.67; p = 0.28). In contrast, factor H mRNA was downregulated in patients with NASH (1.00±0.09 vs. 0.71±0.06; p<0.05) and a similar trend was observed with hepatic protein levels (1.12±0.16 vs. 0.78±0.07; p = 0.08). Collectively, these data suggest a role for alternative pathway activation in driving hepatic inflammation in NASH. Therefore, alternative pathway factors may be considered attractive targets for treating NASH by inhibiting complement activation.

Human intestinal microbiota composition is associated with local and systemic inflammation in obesity.

OBJECTIVE: Intestinal microbiota have been suggested to contribute to the development of obesity, but the mechanism remains elusive. The relationship between microbiota composition, intestinal permeability, and inflammation in nonobese and obese subjects was investigated. DESIGN AND METHODS: Fecal microbiota composition of 28 subjects (BMI 18.6-60.3 kg m(-2) ) was analyzed by a phylogenetic profiling microarray. Fecal calprotectin and plasma C-reactive protein levels were determined to evaluate intestinal and systemic inflammation. Furthermore, HbA1c , and plasma levels of transaminases and lipids were analyzed. Gastroduodenal, small intestinal, and colonic permeability were assessed by a multisaccharide test. RESULTS: Based on microbiota composition, the study population segregated into two clusters with predominantly obese (15/19) or exclusively nonobese (9/9) subjects. Whereas intestinal permeability did not differ between clusters, the obese cluster showed reduced bacterial diversity, a decreased Bacteroidetes/Firmicutes ratio, and an increased abundance of potential proinflammatory Proteobacteria. Interestingly, fecal calprotectin was only detectable in subjects within the obese microbiota cluster (n = 8/19, P = 0.02). Plasma C-reactive protein was also increased in these subjects (P = 0.0005), and correlated with the Bacteroidetes/Firmicutes ratio (rs = -0.41, P = 0.03). CONCLUSIONS: Intestinal microbiota alterations in obese subjects are associated with local and systemic inflammation, suggesting that the obesity-related microbiota composition has a proinflammatory effect.

Endoscopic duodenal-jejunal bypass liner rapidly improves type 2 diabetes.

BACKGROUND: Bariatric procedures excluding the proximal small intestine improve glycemic control in type 2 diabetes within days. To gain insight into the mediators involved, we investigated factors regulating glucose homeostasis in patients with type 2 diabetes treated with the novel endoscopic duodenal-jejunal bypass liner (DJBL). METHODS: Seventeen obese patients (BMI 30-50 kg/m(2)) with type 2 diabetes received the DJBL for 24 weeks. Body weight and type 2 diabetes parameters, including HbA1c and plasma levels of glucose, insulin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon, were analyzed after a standard meal before, during, and 1 week after DJBL treatment. RESULTS: At 24 weeks after implantation, patients had lost 12.7 ± 1.3 kg (p < 0.01), while HbA1c had improved from 8.4 ± 0.2 to 7.0 ± 0.2 % (p < 0.01). Both fasting glucose levels and the postprandial glucose response were decreased at 1 week after implantation and remained decreased at 24 weeks (baseline vs. week 1 vs. week 24: 11.6 ± 0.5 vs. 9.0 ± 0.5 vs. 8.6 ± 0.5 mmol/L and 1,999 ± 85 vs. 1,536 ± 51 vs. 1,538 ± 72 mmol/L/min, both p < 0.01). In parallel, the glucagon response decreased (23,762 ± 4,732 vs. 15,989 ± 3,193 vs. 13,1207 ± 1,946 pg/mL/min, p < 0.05) and the GLP-1 response increased (4,440 ± 249 vs. 6,407 ± 480 vs. 6,008 ± 429 pmol/L/min, p < 0.01). The GIP response was decreased at week 24 (baseline-115,272 ± 10,971 vs. week 24-88,499 ± 10,971 pg/mL/min, p < 0.05). Insulin levels did not change significantly. Glycemic control was still improved 1 week after explantation. CONCLUSIONS: The data indicate DJBL to be a promising treatment for obesity and type 2 diabetes, causing rapid improvement of glycemic control paralleled by changes in gut hormones.

[Practice guideline for the treatment of morbid obesity]. / Richtlijn voor de behandeling van morbide obesitas.

The increasing prevalence of obesity and its related comorbidities represents an increasing burden for the Dutch health care and requires effective therapy. The primary treatment of obesity consists of lifestyle interventions directed at lifestyle change; in morbidly obese subjects only bariatric surgery is cost-effective in the long term, with respect to both weight loss and reduction in comorbidity. There is a new Dutch multidisciplinary practice guideline on the treatment of morbid obesity, in which the following aspects are covered: indications for surgery, pre-operative policy advice, considerations for the type of operation, and the short and long term follow-up after bariatric surgery. Patients between 18 and 65 years old are eligible for bariatric surgery if they have a BMI ≥ 40 kg/m2 or a BMI ≥ 35 kg/m2 in the presence of comorbidity. In adolescents under 18 bariatric surgery should only be performed in a research setting; in patients older than 65 years bariatric surgery can be performed exceptionally, preferably in a centre with large experience.

An update on less invasive and endoscopic techniques mimicking the effect of bariatric surgery.

Obesity (BMI 30-35 kg/m(2)) and its associated disorders such as type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular disease have reached pandemic proportions worldwide. For the morbidly obese population (BMI 35-50 kg/m(2)), bariatric surgery has proven to be the most effective treatment to achieve significant and sustained weight loss, with concomitant positive effects on the metabolic syndrome. However, only a minor percentage of eligible candidates are treated by means of bariatric surgery. In addition, the expanding obesity epidemic consists mostly of relatively less obese patients who are not (yet) eligible for bariatric surgery. Hence, less invasive techniques and devices are rapidly being developed. These novel entities mimic several aspects of bariatric surgery either by gastric restriction (gastric balloons, gastric plication), by influencing gastric function (gastric botulinum injections, gastric pacing, and vagal nerve stimulation), or by partial exclusion of the small intestine (duodenal-jejunal sleeve). In the last decade, several novel less invasive techniques have been introduced and some have been abandoned again. The aim of this paper is to discuss the safety, efficacy, complications, reversibility, and long-term results of these latest developments in the treatment of obesity.

[EndoBarrier for counteracting obesity and metabolic syndrome]. / EndoBarrier tegen obesitas en het metabool syndroom.

The prevalence of obesity is increasing worldwide. Its primary treatment consists of lifestyle changes. In severely obese (BMI > 40 kg/m2 or ≥ 35 kg/m2 with comorbidity) patients though, bariatric surgery has been found to be the only way to achieve permanent weight loss. Operations such as the placement of a gastric band or a gastric bypass can, however, lead to complications and necessitate secondary interventions. In search of less invasive treatments, placement of the EndoBarrier duodenal jejunal bypass liner appears to be a promising, safe and effective method for facilitating weight loss. The EndoBarrier is a plastic flexible tube which is gastroscopically placed in the duodenal bulb, directly behind the pylorus. It extends from the duodenum to the proximal jejunum. Recent studies have demonstrated significant weight reduction in comparison to control-diet patients. Concomitant positive effects on cardiovascular risk factors including diabetes type 2 were observed. A multicentre trial is currently being executed in order to unravel the mechanism behind these effects.

Small intestinal alterations in severely obese hyperglycemic subjects.

CONTEXT: Type 2 diabetes mellitus (DM2) is associated with small intestinal hyperplasia and hypertrophy in rodents. Moreover, the small intestine is increasingly acknowledged to play a role in the pathophysiology of DM2. OBJECTIVE: The objective of the study was to investigate the relation between plasma markers of small intestinal function and chronic hyperglycemia in man. DESIGN, SETTING, AND PARTICIPANTS: We conducted a cross-sectional observational study of 40 severely obese subjects with chronic hyperglycemia and 30 severely obese subjects without chronic hyperglycemia who were indicated for bariatric surgery. MAIN OUTCOME MEASURES: We assessed plasma levels of citrulline, representing small intestinal enterocyte mass, intestinal fatty acid binding protein (I-FABP), a marker of enterocyte loss, and glucagon-like peptide-2, an intestinotrophic factor, and related them to glycated hemoglobin (HbA(1c)) levels. RESULTS: Plasma citrulline and I-FABP levels were both significantly elevated in subjects with chronic hyperglycemia (HbA(1c) > 6.0%) compared with subjects with a normal HbA(1c) (≤ 6.0%) (citrulline, 35 ± 2.1 µm vs. 26 ± 1.4 µm, P = 0.001; I-FABP, 140 ± 22 pg/ml vs. 69 ± 14 pg/ml, P = 0.001). Moreover, plasma citrulline and I-FABP levels correlated with HbA(1c) levels (citrulline, r(s) = 0.30, P = 0.02; I-FABP, r(s) = 0.33, P = 0.005). The I-FABP to citrulline ratio was higher in subjects with an elevated HbA(1c) (4.0 vs. 3.1, P = 0.03). Plasma glucagon-like peptide-2 levels were not related to citrulline or I-FABP levels (r(s) = 0.06, P = 0.67; r(s) 0.08, P = 0.54, respectively). CONCLUSION: Chronically elevated glucose levels in obese individuals are associated with increased small intestinal enterocyte mass and increased enterocyte loss. These findings argue for the further exploration of the role of the intestine in the pathophysiology of DM2.

Co-expressed immune and metabolic genes in visceral and subcutaneous adipose tissue from severely obese individuals are associated with plasma HDL and glucose levels: a microarray study.

BACKGROUND: Excessive accumulation of body fat, in particular in the visceral fat depot, is a major risk factor to develop a variety of diseases such as type 2 diabetes. The mechanisms underlying the increased risk of obese individuals to develop co-morbid diseases are largely unclear.We aimed to identify genes expressed in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) that are related to blood parameters involved in obesity co-morbidity, such as plasma lipid and glucose levels, and to compare gene expression between the fat depots. METHODS: Whole-transcriptome SAT and VAT gene expression levels were determined in 75 individuals with a BMI >35 kg/m2. Modules of co-expressed genes likely to be functionally related were identified and correlated with BMI, plasma levels of glucose, insulin, HbA1c, triglycerides, non-esterified fatty acids, ALAT, ASAT, C-reactive protein, and LDL- and HDL cholesterol. RESULTS: Of the approximately 70 modules identified in SAT and VAT, three SAT modules were inversely associated with plasma HDL-cholesterol levels, and a fourth module was inversely associated with both plasma glucose and plasma triglyceride levels (p < 5.33 x 10(-5)). These modules were markedly enriched in immune and metabolic genes. In VAT, one module was associated with both BMI and insulin, and another with plasma glucose (p < 4.64 x 10(-5)). This module was also enriched in inflammatory genes and showed a marked overlap in gene content with the SAT modules related to HDL. Several genes differentially expressed in SAT and VAT were identified. CONCLUSIONS: In obese subjects, groups of co-expressed genes were identified that correlated with lipid and glucose metabolism parameters; they were enriched with immune genes. A number of genes were identified of which the expression in SAT correlated with plasma HDL cholesterol, while their expression in VAT correlated with plasma glucose. This underlines both the singular importance of these genes for lipid and glucose metabolism and the specific roles of these two fat depots in this respect.