Serum and Lymphocytic Neurotrophins Profiles in Systemic Lupus Erythematosus: a Case-Control Study

Background

Neurotrophins play a central role in the development and maintenance of the nervous system. However, neurotrophins can also modulate B and T cell proliferation and activation, especially via autocrine loops. We hypothesized that both serum and lymphocytic neurotrophin levels may be deregulated in systemic Lupus erythematosus (SLE) and may reflect clinical symptoms of the disease.

Methods

Neurotrophins in the serum (ELISA tests) and lymphocytes (flow cytometry) were measured in 26 SLE patients and 26 control subjects. Th1 (interferon-γ) and Th2 (IL-10) profiles and serum concentration of BAFF were assessed by ELISA in the SLE and control subjects.

Findings

We have demonstrated that both NGF and BDNF serum levels are higher in SLE patients than healthy controls (p=0.003 and p<0.001), independently of Th1 or Th2 profiles. Enhanced serum NT-3 levels (p=0.003) were only found in severe lupus flares (i.e. SLEDAI ≥ 10) and significantly correlated with complement activation (decreased CH 50, Γ=-0.28, p=0.03). Furthermore, there was a negative correlation between serum NGF levels and the number of circulating T regulatory cells (Γ=0.48, p=0.01). In circulating B cells, production of both NGF and BDNF was greater in SLE patients than in healthy controls. In particular, the number of NGF-secreting B cells correlated with decreased complement levels (p=0.05). One month after SLE flare treatment, BDNF levels decreased; in contrast, NGF and NT-3 levels remained unchanged.

Conclusion

This study demonstrates that serum and B cell levels of both NGF and BDNF are increased in SLE, suggesting that the neurotrophin production pathway is deregulated in this disease. These results must be confirmed in a larger study with naive SLE patients, in order to avoid the potential confounding influence of prior immune-modulating treatments on neurotrophin levels.     

Glycosaminoglycan remodeling during chondrogenic differentiation of human bone marrow−/synovial-derived mesenchymal stem/stromal cells under normoxia and hypoxia

Glycosaminoglycans (GAGs) are major components of cartilage extracellular matrix (ECM), which play an important role in tissue homeostasis not only by providing mechanical load resistance, but also as signaling mediators of key cellular processes such as adhesion, migration, proliferation and differentiation. Specific GAG types as well as their disaccharide sulfation patterns can be predictive of the tissue maturation level but also of disease states such as osteoarthritis. In this work, we used a highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to perform a comparative study in terms of temporal changes in GAG and disaccharide composition between tissues generated from human bone marrow- and synovial-derived mesenchymal stem/stromal cells (hBMSC/hSMSC) after chondrogenic differentiation under normoxic (21% O₂) and hypoxic (5% O₂) micromass cultures. The chondrogenic differentiation of hBMSC/hSMSC cultured under different oxygen tensions was assessed through aggregate size measurement, chondrogenic gene expression analysis and histological/immunofluorescence staining in comparison to human chondrocytes. For all the studied conditions, the compositional analysis demonstrated a notable increase in the average relative percentage of chondroitin sulfate (CS), the main GAG in cartilage composition, throughout MSC chondrogenic differentiation. Additionally, hypoxic culture conditions resulted in significantly different average GAG and CS disaccharide percentage compositions compared to the normoxic ones. However, such effect was considerably more evident for hBMSC-derived chondrogenic aggregates. In summary, the GAG profiles described here may provide new insights for the prediction of cartilage tissue differentiation/disease states and to characterize the quality of MSC-generated chondrocytes obtained under different oxygen tension culture conditions.

     

Neonatal environment exerts a sustained influence on the development of the intestinal microbiota and metabolic phenotype

The postnatal environment, including factors such as weaning and acquisition of the gut microbiota, has been causally linked to the development of later immunological diseases such as allergy and autoimmunity, and has also been associated with a predisposition to metabolic disorders. We show that the very early-life environment influences the development of both the gut microbiota and host metabolic phenotype in a porcine model of human infants. Farm piglets were nursed by their mothers for 1 day, before removal to highly controlled, individual isolators where they received formula milk until weaning at 21 days. The experiment was repeated, to create two batches, which differed only in minor environmental fluctuations during the first day. At day 1 after birth, metabolic profiling of serum by ¹H nuclear magnetic resonance spectroscopy demonstrated significant, systemic, inter-batch variation which persisted until weaning. However, the urinary metabolic profiles demonstrated that significant inter-batch effects on 3-hydroxyisovalerate, trimethylamine-N-oxide and mannitol persisted beyond weaning to at least 35 days. Batch effects were linked to significant differences in the composition of colonic microbiota at 35 days, determined by 16 S pyrosequencing. Different weaning diets modulated both the microbiota and metabolic phenotype independently of the persistent batch effects. We demonstrate that the environment during the first day of life influences development of the microbiota and metabolic phenotype and thus should be taken into account when interrogating experimental outcomes. In addition, we suggest that intervention at this early time could provide ‘metabolic rescue'' for at-risk infants who have undergone aberrant patterns of initial intestinal colonisation.     

Capillary electrophoretic separation of high-molecular-weight poly(ethylene glycol)-modified proteins

This study was designed to demonstrate the utility of capillary electrophoresis (CE) for separating high-molecular-weight poly(ethylene glycol) (PEG)-conjugated proteins. As a CE method, sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE) was applied to analyze interferon alpha (IFN) modified with branched and trimer-structured PEG molecules. Five mono-PEG-IFN conjugates prepared with two branched PEGs (MW 20 and 40 kDa) and three trimer-structured PEGs (MW 23.5, 43.5, and 47 kDa) were purified by cation-exchange chromatography and their masses were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The SDS-CGE method showed high separation capacity by differentiating PEG-IFN conjugates with small differences in molecular size, such as PEG_40K-, PEG_43.5K-, and PEG_47K-IFNs, and it was useful for checking the purity of each mono-PEG-IFN. This study shows that SDS-CGE can well be utilized in the development and quality control of PEGylated proteins prepared with various types of PEG.     

Comparison of random-effects meta-analysis models for the relative risk in the case of rare events: A simulation study

Pooling the relative risk (RR) across studies investigating rare events, for example, adverse events, via meta-analytical methods still presents a challenge to researchers. The main reason for this is the high probability of observing no events in treatment or control group or both, resulting in an undefined log RR (the basis of standard meta-analysis). Other technical challenges ensue, for example, the violation of normality assumptions, or bias due to exclusion of studies and application of continuity corrections, leading to poor performance of standard approaches. In the present simulation study, we compared three recently proposed alternative models (random-effects [RE] Poisson regression, RE zero-inflated Poisson [ZIP] regression, binomial regression) to the standard methods in conjunction with different continuity corrections and to different versions of beta-binomial regression. Based on our investigation of the models' performance in 162 different simulation settings informed by meta-analyses from the Cochrane database and distinguished by different underlying true effects, degrees of between-study heterogeneity, numbers of primary studies, group size ratios, and baseline risks, we recommend the use of the RE Poisson regression model. The beta-binomial model recommended by Kuss (2015) also performed well. Decent performance was also exhibited by the ZIP models, but they also had considerable convergence issues. We stress that these recommendations are only valid for meta-analyses with larger numbers of primary studies. All models are applied to data from two Cochrane reviews to illustrate differences between and issues of the models. Limitations as well as practical implications and recommendations are discussed; a flowchart summarizing recommendations is provided.     

Governance options for science–policy interfaces on biodiversity and ecosystem services: comparing a network versus a platform approach

Science–policy-interfaces (SPIs) are expected to go beyond the linear model of scientific policy advice through creating spaces for exchange and dialogue between ‘policy’ and ‘knowledge’. Given that most environmental issues require inter- and transdisciplinary approaches, SPIs must take into account a variety of knowledge types, views and interests of scientists, policymakers and other decision makers. Moreover, acceptance and durability of SPIs depend largely on their perceived legitimacy and the credibility of their knowledge-gathering processes, providing additional challenges for their internal organisation. As the interplay between different knowledge types and decision making is far from neutral, a reflexive approach is required in the design of an SPI so that it is capable of learning from past experiences. The aim of this article is to discuss which governance arrangements could best support the development of an effective and legitimate SPI for European biodiversity politics. We analyse different options for facilitating the implementation of a ‘Network of Knowledge’ approach. This approach has been developed to improve the interface between diverse knowledge-holder communities and decision making processes for biodiversity and ecosystem services—a field where multi-scalar and multi-dimensional problems arise. In this article, we develop and discuss two stylized extreme governance models as our starting point: an `informal network model´, which almost entirely depends on the dedication of individuals, versus a more formalized `platform model´, predominantly based on the needs and interests of the organisations involved. We discuss the pros and cons of each of these models in reaching their objectives and in developing sound governing processes for a ‘Network of Knowledge’. From this discussion, we derive a recommended design for the reflexive governance of such a network in the context of the European Union and finish by discussing some more general lessons learnt.     

Continuous immobilized yeast reactor system for complete beer fermentation using spent grains and corncobs as carrier materials

Despite extensive research carried out in the last few decades, continuous beer fermentation has not yet managed to outperform the traditional batch technology. An industrial breakthrough in favour of continuous brewing using immobilized yeast could be expected only on achievement of the following process characteristics: simple design, low investment costs, flexible operation, effective process control and good product quality. The application of cheap carrier materials of by-product origin could significantly lower the investment costs of continuous fermentation systems. This work deals with a complete continuous beer fermentation system consisting of a main fermentation reactor (gas-lift) and a maturation reactor (packed-bed) containing yeast immobilized on spent grains and corncobs, respectively. The suitability of cheap carrier materials for long-term continuous brewing was proved. It was found that by fine tuning of process parameters (residence time, aeration) it was possible to adjust the flavour profile of the final product. Consumers considered the continuously fermented beer to be of a regular quality. Analytical and sensorial profiles of both continuously and batch fermented beers were compared.