Activation of a passive, mesoporous silica nanoparticle layer through attachment of bacterially-derived carbon-quantum-dots for protection and functional enhancement of probiotics

Probiotic bacteria employed for food supplementation or probiotic-assisted antibiotic treatment suffer from passage through the acidic gastro-intestinal tract and unintended killing by antibiotics. Carbon-quantum-dots (CQDs) derived from bacteria can inherit different chemical groups and associated functionalities from their source bacteria. In order to yield simultaneous, passive protection and enhanced, active functionality, we attached CQDs pyrolytically carbonized at 220 degrees C from Lactobacillus acidophilus or Escherichia coli to a probiotic strain (Bifidobacterium infantis) using boron hydroxyl-modified, mesoporous silica nanoparticles as an intermediate encapsulating layer. Fourier-transform-infrared-spectroscopy, X-ray-photoelectron-spectroscopy and scanning-electron-microscopy were employed to demonstrate successful encapsulation of B. infantis by silica nano-particles and subsequent attachment of bacterially-derived CQDs. Thus encapsulated B. infantis possessed a negative surface charge and survived exposure to simulated gastric fluid and antibiotics better than unencapsulated B. infantis. During B. infantis assisted antibiotic treatment of intestinal epithelial layers colonized by E. coli, encapsulated B. infantis adhered and survived in higher numbers on epithelial layers than B. infantis without encapsulation or encapsulated with only silica nanoparticles. Moreover, higher E. coli killing due to increased reactive-oxygen-species generation was observed. In conclusion, the active, protective encapsulation described enhanced the probiotic functionality of B. infantis, which might be considered as a first step towards a fully engineered, probiotic nanoparticle

Lipopolysaccharide-induced suppression of airway Th2 responses does not require IL-12 production by dendritic cells

The prevalence of atopic asthma, a Th2-dependent disease, is reaching epidemic proportions partly due to improved hygiene in industrialized countries. There is an inverse correlation between the level of environmental endotoxin exposure and the prevalence of atopic sensitization. As dendritic cells (DC) have been implicated in causing sensitization to inhaled Ag, we studied the effect of endotoxin on Th2 development induced by bone marrow DC in vitro and by intratracheal injection in vivo, with particular emphasis on the role played by the polarizing cytokine IL-12. Bone marrow-derived DC stimulated with Escherichia coli O26:B6 LPS produced IL-12p70 for a limited period of time, after which production became refractory to further stimulation with CD40 ligand, a phenomenon previously called "exhaustion." The level of IL-12 production of DC did not correlate with Th1 development, as exhausted OVA-pulsed DC were still capable of shifting the cytokine pattern of responding OVA-specific Th cells toward Th1 in vitro and in vivo. When mice were first immunized by intratracheal injection of OVA-DC and subsequently challenged with OVA aerosol, prior in vitro stimulation of DC with LPS reduced the development of airway eosinophilia and Th2 cytokine production. Most surprisingly, the capacity of LPS to reduce Th2-dependent eosinophilic airway inflammation was IL-12-independent altogether, as IL-12p40 knockout DC had a similar reduced capacity to prime for Th2 responses. These results suggest that LPS reduces sensitization to inhaled Ag by reducing DC-driven Th2 development, but that IL-12 is not necessary for this effect

Preconception lifestyle intervention in women with obesity and echocardiographic indices of cardiovascular health in their children

Background: Improving maternal lifestyle before conception may prevent the adverse effects of maternal obesity on their children’s future cardiovascular disease (CVD) risk. In the current study, we examined whether a preconception lifestyle intervention in women with obesity could alter echocardiographic indices of cardiovascular health in their children. Methods: Six years after a randomized controlled trial comparing the effects of a 6-month preconception lifestyle intervention in women with obesity and infertility prior to fertility care to prompt fertility care, 315 of the 341 children conceived within 24 months after randomization were eligible for this study. The intervention was aimed at weight loss (≥5% or until BMI < 29 kg/m2). Children underwent echocardiographic assessment of cardiac structure and function, conducted by a single pediatric cardiologist, blinded to group allocation. Results were adjusted for multiple variables including body surface area, age, and sex in linear regression analyses. Results: Sixty children (32 girls, 53%) were included, mean age 6.5 years (SD 1.09). Twenty-four children (40%) were born to mothers in the intervention group. Children of mothers from the intervention group had a lower end-diastolic interventricular septum thickness (−0.88 Z-score, 95%CI −1.18 to −0.58), a lower left ventricle mass index (−8.56 g/m2, 95%CI −13.09 to −4.03), and higher peak systolic and early diastolic annular velocity of the left ventricle (1.43 cm/s 95%CI 0.65 to 2.20 and 2.39 cm/s 95%CI 0.68 to 4.11, respectively) compared to children of mothers from the control group. Conclusions: Children of women with obesity, who underwent a preconception lifestyle intervention, had improved cardiac structure and function; a thinner interventricular septum, lower left ventricle mass, and improved systolic and diastolic tissue Doppler velocities. Despite its high attrition rates, our study provides the first experimental human evidence suggesting that preconception lifestyle interventions may present a method of reducing CVD risk in the next generation. Clinical trial registration: LIFEstyle study: Netherlands Trial Register: NTR1530 (https://www.trialregister.nl/trial/1461). This follow-up study was approved by the medical ethics committee of the University Medical Centre Groningen (METC code: 2008/284)

Gastrointestinal Endoscopic Terminology Coding (GET-C): A WHO-Approved Extension of the ICD-10

Technological developments have greatly promoted interest in the use of computer systems for recording findings and images at endoscopy and creating databases. The aim of this study was to develop a comprehensive WHO-approved code system for gastrointestinal endoscopic terminology. The International Classification of Diseases, 10th edition (ICD-10), and the ICD-10 clinical modification (ICD-10-CM) were expanded to allow description of every possible gastrointestinal endoscopic term under conditions defined by the WHO. Classifications of specific gastrointestinal disorders and endoscopic locations were added. A new chapter was developed for frequently used terminology that could not be classified in the existing ICD-10, such as descriptions of therapeutic procedures. The new extended code system was named Gastrointestinal Endoscopic Terminology Coding (GET-C). The GET-C is a complete ICD-10-related code system that can be used within every endoscopic database program for all specific endoscopic terms. The GET-C is available for free at http://www.trans-it.org/

CorNet : assigning function to networks of co-evolving residues by automated literature mining

CorNet is a web-based tool for the analysis of co-evolving residue positions in protein superfamily sequence alignments. CorNet projects external information such as mutation data extracted from literature on interactively displayed groups of co-evolving residue positions to shed light on the functions associated with these groups and the residues in them. We used CorNet to analyse six enzyme super-families and found that groups of strongly co-evolving residues tend to consist of residues involved in a same function such as activity, specificity, co-factor binding, or enantioselectivity. This finding allows to assign a function to residues for which no data is available yet in the literature. A mutant library was designed to mutate residues observed in a group of co-evolving residues predicted to be involved in enantioselectivity, but for which no literature data is available yet. The resulting set of mutations indeed showed many instances of increased enantioselectivity

Hepatic Farnesoid X-Receptor Isoforms α2 and α4 Differentially Modulate Bile Salt and Lipoprotein Metabolism in Mice

The nuclear receptor FXR acts as an intracellular bile salt sensor that regulates synthesis and transport of bile salts within their enterohepatic circulation. In addition, FXR is involved in control of a variety of crucial metabolic pathways. Four FXR splice variants are known, i.e. FXRα1-4. Although these isoforms show differences in spatial and temporal expression patterns as well as in transcriptional activity, the physiological relevance hereof has remained elusive. We have evaluated specific roles of hepatic FXRα2 and FXRα4 by stably expressing these isoforms using liver-specific self-complementary adeno-associated viral vectors in total body FXR knock-out mice. The hepatic gene expression profile of the FXR knock-out mice was largely normalized by both isoforms. Yet, differential effects were also apparent; FXRα2 was more effective in reducing elevated HDL levels and transrepressed hepatic expression of Cyp8b1, the regulator of cholate synthesis. The latter coincided with a switch in hydrophobicity of the bile salt pool. Furthermore, FXRα2-transduction caused an increased neutral sterol excretion compared to FXRα4 without affecting intestinal cholesterol absorption. Our data show, for the first time, that hepatic FXRα2 and FXRα4 differentially modulate bile salt and lipoprotein metabolism in mice

Changes in Plasma Copeptin Levels during Hemodialysis:Are the Physiological Stimuli Active in Hemodialysis Patients?

Plasma levels of copeptin, a surrogate marker for the vasoconstrictor hormone arginine vasopressin (AVP), are increased in hemodialysis patients. Presently, it is unknown what drives copeptin levels in hemodialysis patients. We investigated whether the established physiological stimuli for copeptin release, i.e. plasma osmolality, blood volume and mean arterial pressure (MAP), are operational in hemodialysis patients.One hundred and eight prevalent, stable hemodialysis patients on a thrice-weekly dialysis schedule were studied during hemodialysis with constant ultrafiltration rate and dialysate conductivity in this observational study. Plasma levels of copeptin, sodium, MAP, and blood volume were measured before, during and after hemodialysis. Multivariate analysis was used to determine the association between copeptin (dependent variable) and the physiological stimuli plasma sodium, MAP, excess weight as well as NT-pro-BNP immediately prior to dialysis and between copeptin and changes of plasma sodium, MAP and blood volume with correction for age, sex and diabetes during dialysis treatment.Patients were 63 ± 15.6 years old and 65% were male. Median dialysis vintage was 1.6 years (IQR 0.7-4.0). Twenty-three percent of the patients had diabetes and 82% had hypertension. Median predialysis copeptin levels were 141.5 pmol/L (IQR 91.0-244.8 pmol/L). Neither predialysis plasma sodium levels, nor NT-proBNP levels, nor MAP were associated with predialysis copeptin levels. During hemodialysis, copeptin levels rose significantly (p<0.01) to 163.0 pmol/L (96.0-296.0 pmol/L). Decreases in blood volume and MAP were associated with increases in copeptin levels during dialysis, whereas there was no significant association between the change in plasma sodium levels and the change in copeptin levels.Plasma copeptin levels are elevated predialysis and increase further during hemodialysis. Volume stimuli, i.e. decreases in MAP and blood volume, rather than osmotic stimuli, are associated with change in copeptin levels during hemodialysis

Impaired Very-Low-Density Lipoprotein catabolism links hypoglycemia to hypertriglyceridemia in Glycogen Storage Disease type Ia

International audiencePrevention of hypertriglyceridemia is one of the biomedical targets in Glycogen Storage Disease type Ia (GSD Ia) patients, yet it is unclear how hypoglycemia links to plasma triglyceride (TG) levels. We analyzed whole-body TG metabolism in normoglycemic (fed) and hypoglycemic (fasted) hepatocyte-specific glucose-6-phosphatase deficient (L-G6pc-/- ) mice. De novo fatty acid synthesis contributed substantially to hepatic TG accumulation in normoglycemic L-G6pc-/- mice. In hypoglycemic conditions, enhanced adipose tissue lipolysis was the main driver of liver steatosis, supported by elevated free fatty acid concentrations in GSD Ia mice and GSD Ia patients. Plasma very-low-density lipoprotein (VLDL) levels were increased in GSD Ia patients and in normoglycemic L-G6pc-/- mice, and further elevated in hypoglycemic L-G6pc-/- mice. VLDL-TG secretion rates were doubled in normo- and hypoglycemic L-G6pc-/- mice, while VLDL-TG catabolism was selectively inhibited in hypoglycemic L-G6pc-/- mice. In conclusion, fasting-induced hypoglycemia in L-G6pc-/- mice promotes adipose tissue lipolysis and arrests VLDL catabolism. This mechanism likely contributes to aggravated liver steatosis and dyslipidemia in GSD Ia patients with poor glycemic control and may explain clinical heterogeneity in hypertriglyceridemia between GSD Ia patients