Valorization of Spirodela polyrrhiza biomass for the production of biofuels for distributed energy

Considering the main objectives of a circular economy, Lemnaceae plants have great potential for different types of techniques to valorize their biomass for use in biofuel production. For this reason, scientific interest in this group of plants has increased in recent years. The aim of this study was to evaluate the effects of salt stress on the growth and development of S. polyrrhiza and the valorization of biomass for biofuel and energy production in a circular economy. Plants were grown in a variety of culture media, including standard 'Z' medium, tap water, 1% digestate from a biogas plant in Piaszczyna (54° 01' 21″ N, 17° 10' 19″ E), Poland) and supplemented with different concentrations of NaCl (from 25 to 100 mM). Plants were cultured under phytotron conditions at 24 °C. After 10 days of culture, plant growth, fresh and dry biomass, as well as physio-chemical parameters such as chlorophyll content index, gas exchange parameters (net photosynthesis, transpiration, stomatal conductance and intercellular CO2 concentration), chlorophyll fluorescence measurements were analyzed. After 10 days of the experiment, the percentage starch content of Spirodela shoot segments was determined. S. polyrrhiza was shown to have a high starch storage capacity under certain unfavorable growth conditions, such as salt stress and nutrient deficiency. In the W2 (50 mM NaCl) series, compared to the control (Control2), starch levels were 76% higher in shoots and 30% lower in roots. The analysis of the individual growth and development parameters of S. polyrrhiza plants in the experiment carried out indicates new possibilities for the use of this group of plants in biofuel and bioethanol production.

Sixteen-week multicentre randomised controlled trial to study the effect of the consumption of an oat beta-glucan-enriched bread versus a whole-grain wheat bread on glycaemic control among persons with pre-diabetes: a study protocol of the CarbHealth study

INTRODUCTION

In 2012, the estimated global prevalence of pre-diabetes was 280 million, and the prevalence is expected to rise to 400 million by 2030. Oat-based foods are a good source of beta-glucans, which have been shown to lower postprandial blood glucose. Studies to evaluate the effectiveness of the long-term intake of beta-glucan-enriched bread as part of a habitual diet among individuals with pre-diabetes are needed. Therefore, we designed a multicentre intervention study in adults with pre-diabetes to investigate the effects of consumption of an oat-derived beta-glucan-enriched bread as part of a normal diet on glycated haemoglobin (HbA1c) in comparison to consumption of whole-grain wheat bread.

METHODS AND ANALYSIS

The CarbHealth trial is a multicentre double-blind randomised controlled 16-week dietary intervention trial in participants 40-70 years of age with a body mass index of ≥27 kg/m² and HbA1c of 35-50 mmol/mol. The study is conducted at four universities located in Norway, Sweden and Germany and uses intervention breads specifically designed for the trial by Nofima AS. The aim is to recruit 250 participants. The primary outcome is the difference in HbA1c between the intervention and the control groups. The main analysis will include intervention group, study centre and baseline HbA1c as independent variables in an analysis of covariance model.

ETHICS AND DISSEMINATION

The study protocol was approved by respective ethical authorities in participating countries. The results of the study will be communicated through publication in international scientific journals and presentations at (inter)national conferences.

TRIAL REGISTRATION NUMBER

NCT04994327.

Paraplegia prevention in aortic aneurysm repair by thoracoabdominal staging with 'minimally invasive staged segmental artery coil embolisation' (MIS²ACE): trial protocol for a randomised controlled multicentre trial

INTRODUCTION

Spinal cord injury (SCI) including permanent paraplegia constitutes a common complication after repair of thoracoabdominal aortic aneurysms. The staged-repair concept promises to provide protection by inducing arteriogenesis so that the collateral network can provide a robust blood supply to the spinal cord after intervention. Minimally invasive staged segmental artery coil embolisation (MIS²ACE) has been proved recently to be a feasible enhanced approach to staged repair.

METHODS AND ANALYSIS

This randomised controlled trial uses a multicentre, multinational, parallel group design, where 500 patients will be randomised in a 1:1 ratio to standard aneurysm repair or to MIS²ACE in 1-3 sessions followed by repair. Before randomisation, physicians document whether open or endovascular repair is planned. The primary endpoint is successful aneurysm repair without substantial SCI 30 days after aneurysm repair. Secondary endpoints include any form of SCI, mortality (up to 1 year), length of stay in the intensive care unit, costs and quality-adjusted life years. A generalised linear mixed model will be used with the logit link function and randomisation arm, mode of repair (open or endovascular repair), the Crawford type and the European System for Cardiac Operative Risk Evaluation (euroSCORE) II as fixed effects and the centre as a random effect. Safety endpoints include kidney failure, respiratory failure and embolic events (also from debris). A qualitative study will explore patient perceptions.

ETHICS AND DISSEMINATION

This trial has been approved by the lead Ethics Committee from the University of Leipzig (435/17-ek) and will be reviewed by each of the Ethics Committees at the trial sites. A dedicated project is coordinating communication and dissemination of the trial.

TRIAL REGISTRATION NUMBER

NCT03434314.

Interleukin-6 predicts inflammation-induced increase of Glucagon-like peptide-1 in humans in response to cardiac surgery with association to parameters of glucose metabolism

Objective

Glucagon-like peptide-1 (GLP-1) is an incretin hormone, which gets secreted in response to nutritional stimuli from the gut mediating glucose-dependent insulin secretion. Interestingly, GLP-1 was recently found to be also increased in response to inflammatory stimuli in an interleukin 6 (IL-6) dependent manner in mice. The relevance of this finding to humans is unknown but has been suggested by the presence of high circulating GLP-1 levels in critically ill patients that correlated with markers of inflammation. This study was performed to elucidate, whether a direct link exists between inflammation and GLP-1 secretion in humans.

Research design and methods

We enrolled 22 non-diabetic patients scheduled for cardiac surgery as a reproducible inflammatory stimulus with repeated blood sampling before and after surgery.

Results

Mean total circulating GLP-1 levels significantly increased in response to surgery from 25.5 ± 15.6 pM to 51.9 ± 42.7 pM which was not found in a control population. This was preceded by an early rise of IL6, which was significantly associated with GLP-1 under inflammatory but not basal conditions. Using repeated measure ANCOVA, IL6 best predicted the observed kinetics of GLP-1, followed by blood glucose concentrations and cortisol plasma levels. Furthermore, GLP-1 plasma concentrations significantly predicted endogenous insulin production as assessed by C-peptide concentrations over time, while an inverse association was found for insulin infusion rate.

Conclusion

We found GLP-1 secretion to be increased in response to inflammatory stimuli in humans, which was associated to parameters of glucose metabolism and best predicted by IL6.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0330-8) contains supplementary material, which is available to authorized users.

Walnut-enriched diet reduces fasting non-HDL-cholesterol and apolipoprotein B in healthy Caucasian subjects: a randomized controlled cross-over clinical trial

BACKGROUND

Walnut consumption is associated with reduced risk of coronary heart disease (CHD).

OBJECTIVE

We assessed the effect of walnuts on lipid and glucose metabolism, adipokines, inflammation and endothelial function in healthy Caucasian men and postmenopausal women ≥50years old.

DESIGN

Forty subjects (mean±SEM: age 60±1years, BMI 24.9±0.6kg/m(2); 30 females) were included in a controlled, cross-over study and randomized to receive first a walnut-enriched (43g/d) and then a Western-type (control) diet or vice-versa, with each lasting 8weeks and separated by a 2-week wash-out. At the beginning and end of each diet phase, measurements of fasting values, a mixed meal test and an assessment of postprandial endothelial function (determination of microcirculation by peripheral artery tonometry) were conducted. Area under the curve (AUC), incremental AUC (iAUC) and treatment×time interaction (shape of the curve) were evaluated for postprandial triglycerides, VLDL-triglycerides, chylomicron-triglycerides, glucose and insulin.

RESULTS

Compared with the control diet, the walnut diet significantly reduced non-HDL-cholesterol (walnut vs. control: -10±3 vs. -3±2mg/dL; p=0.025) and apolipoprotein-B (-5.0±1.3 vs. -0.2±1.1mg/dL; p=0.009) after adjusting for age, gender, BMI and diet sequence. Total cholesterol showed a trend toward reduction (p=0.073). Fasting VLDL-cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and glucose, insulin, HOMA-IR, and HbA1c did not change significantly. Similarly, fasting adipokines, C-reactive protein, biomarkers of endothelial dysfunction, postprandial lipid and glucose metabolism and endothelial function were unaffected.

CONCLUSION

Daily consumption of 43g of walnuts for 8weeks significantly reduced non-HDL-cholesterol and apolipoprotein-B, which may explain in part the epidemiological observation that regular walnut consumption decreases CHD risk.

Circulating concentrations of GLP-1 are associated with coronary atherosclerosis in humans

Background

GLP-1 is an incretine hormone which gets secreted from intestinal L-cells in response to nutritional stimuli leading to pancreatic insulin secretion and suppression of glucagon release. GLP-1 further inhibits gastric motility and reduces appetite which in conjunction improves postprandial glucose metabolism. Additional vasoprotective effects have been described for GLP-1 in experimental models. Despite these vasoprotective actions, associations between endogenous levels of GLP-1 and cardiovascular disease have yet not been investigated in humans which was the aim of the present study.

Methods

GLP-1 serum levels were assessed in a cohort of 303 patients receiving coronary CT-angiography due to typical or atypical chest pain.

Results

GLP-1 was found to be positively associated with total coronary plaque burden in a fully adjusted model containing age, sex, BMI, hypertension, diabetes mellitus, smoking, triglycerides, LDL-C (low density lipoprotein cholesterol), hsCRP (high-sensitive C-reactive protein), and eGFR (estimated glomerular filtration rate) (OR: 2.53 (95% CI: 1.12 – 6.08; p = 0.03).

Conclusion

Circulating GLP-1 was found to be positivity associated with coronary atherosclerosis in humans. The clinical relevance of this observation needs further investigations.

Changes in body weight, glucose homeostasis, lipid profiles, and metabolic syndrome after restrictive bariatric surgery

OBJECTIVE

Bariatric surgery is an established therapy for morbid obesity. We evaluated the effects of sleeve-gastrectomy on weight, glucose and lipid metabolism and prevalence of metabolic-syndrome for up to 2 years.

METHODS

In 52 morbidly obese patients weight, BMI, total-cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, Lipoprotein(a), glucose, HbA1c, insulin, and criteria defining the metabolic-syndrome were determined preoperatively and 6 (n=52), 12 (n=41) and 24 (n=5) months after surgery.

RESULTS

BMI decreased from 51±8 kg/m² to 40±7, 39±8, and 38±9 kg/m² at 6, 12, and 24 months postoperatively. Glucose and HbA1c changed from 116±44 to 93±21 and 94±18 mg/dl and 6.0±1.3 to 5.4±0.8 and 5.4±0.8% at 6 and 12 months postoperatively. Triglycerides decreased from 159±87 to 116±41 and 116±62 mg/dl, while HDL--cholesterol increased from 46±12 to 50±12 and 56±13 mg/dl at 6 and 12 months. None of the changes correlated with changes in weight. Prevalence of metabolic syndrome decreased from 81% to 36% and 34% at 6 and 12 months, with individual criteria (central obesity, triglycerides, HDL-cholesterol, hypertension, and fasting glucose) being reduced by 8/12%, 31/28%, 12/37%, 27/30%, and 38/31% at 6/12 months, respectively. The decrease in triglycerides and HbA1c was more pronounced in hypertriglyceridemic patients compared to normo-triglyceridemic patients, while there was no significant difference between diabetic and non-diabetic patients.

CONCLUSIONS

This is the first study evaluating sleeve-gastrectomy in German patients. Our data indicate that sleeve-gastrectomy induces a similar metabolic improvement as malabsorptive surgery. Although metabolic improvement did not correlate with weight reduction, improvement almost exclusively occurred within the first 6 months, when significant weight reduction occurred. It is unclear whether this relates to the operative techniques or to the selection of patients.

Kinetic studies on the CuO/gamma-Al2O3 sorbent regeneration by methane--topochemical approach

CuO impregnated gamma-Al2O3 support provides convenient adsorption and regeneration characteristics. These features give the potential to regard this chemisorption process as more effective, feasible and widely accepted than lime and limestone scrubbing in the removal of SO2 from the outlet gases. Thermogravimetric tests on the regeneration of the CuO/gamma-Al2O3 exhausted sorbent (first stage of the regeneration, CuSO4-->Cu0) with methane were conducted. Commercially available 1/8" gamma-Al2O3 spheres, loaded with 5.8 wt % of Cu were investigated. The tests concerning the isothermal regeneration kinetics were performed at temperatures: T = 700, 727 and 750 K, while a 20 cm3 min(-1) flow of pure methane was used. To select the mechanism of the regeneration reaction, as well as to evaluate their kinetic parameters of the rate equations, the TGA data were compared with the series of theoretical topochemical kinetic models as advocated by Gardner, Hancock and Sharp's approach. The kinetic mechanism of the regeneration reaction in the initial stage of the process may be originally interpreted as the combination of both boundary-surface-controlled reaction (contracting sphere) and the first-order kinetics models. Various diffusion limited kinetic equations have proved useful for the description of the final stage of the process. Both proposed models (two kinetic and four diffusion ones) fit fairly well to the experimental data (in their limited validity ranges) obtained in all three temperature values studied.

Characterization of the human platelet/endothelial cell adhesion molecule-1 promoter: identification of a GATA-2 binding element required for optimal transcriptional activity

Platelet/endothelial cell adhesion molecule-1 (PECAM-1) is a 130-kD member of the Ig gene superfamily that is expressed on platelets, endothelial cells, and certain leukocyte subsets. To examine the factors controlling vascular-specific expression of PECAM-1, we cloned the 5'-flanking region of the PECAM-1 gene and analyzed its transcriptional activity. 5'-Rapid amplification of cDNA ends (5'-RACE) analysis showed that transcription initiation occurred at several closely spaced nearby sites originating approximately 204 bp upstream from the translation start site. Analysis of the sequence immediately upstream from the transcription initiation site (TIS) showed no canonical TATA or CAAT elements, however an initiator element commonly found in TATA-less promoters encompassed the TIS. 5'-serially truncated PECAM-1 promoter segments cloned in front of a luciferase reporter drove transcription in both a lineage- and orientation-specific manner. Putative cis-acting control elements present within a 300-bp core promoter included two ets sites, an Sp1 site, tandem E-box domains, two GATA-associated sites (CACCC), an AP-2 binding site, and a GATA element at -24. Mutational analysis showed that optimal transcriptional activity required the GATA sequence at position -24, and gel-shift assays further showed that the GATA-2 transcription factor, but not GATA-1, bound to this region of the PECAM-1 promoter. Understanding the cis- and transacting factors that regulate the tissue-specific expression of PECAM-1 should increase our understanding of the mechanisms by which vascular-specific gene expression is achieved.

Effect of interferon-alpha on the steady-state levels of thymine, thymidine, guanine, and guanosine metabolites in herpes simplex virus-type 1-infected cells

Interferon-alpha (IFN-alpha) combined with acyclic guanine analogs synergistically inhibits replication of herpes simplex virus type 1. IFN-alpha treatment influenced the metabolism of exogenously supplied nucleobases and nucleosides in a manner expected to contribute to synergistic activity. IFN-alpha treatment of infected human cornea stromal cells or Vero cells significantly reduced steady-state levels of acid soluble metabolites of thymine, as well as thymidine, that accumulate early during virus replication but did not affect metabolism of thymine and thymidine in uninfected cells. IFN-alpha treatment significantly reduced the ability of uninfected cells to accumulate acid-soluble metabolites from guanine, but not guanosine. The effects of IFN-alpha on nucleobase/nucleoside metabolism could contribute to synergistic antiviral activity by reducing the accumulation of thymidine/thymine metabolites and decreasing the guanine taken into cells.