Tezepelumab decreases airway epithelial IL-33 and T2-inflammation in response to viral stimulation in patients with asthma

BACKGROUND

Respiratory virus infections are main triggers of asthma exacerbations. Tezepelumab, an anti-TSLP mAb, reduces exacerbations in patients with asthma, but the effect of blocking TSLP on host epithelial resistance and tolerance to virus infection is not known.

AIM

To examine effects of blocking TSLP in patients with asthma on host resistance (IFNβ, IFNλ, and viral load) and on the airway epithelial inflammatory response to viral challenge.

METHODS

Bronchoalveolar lavage fluid (BALF, n = 39) and bronchial epithelial cells (BECs) were obtained from patients with uncontrolled asthma before and after 12 weeks of tezepelumab treatment (n = 13) or placebo (n = 13). BECs were cultured in vitro and exposed to the viral infection mimic poly(I:C) or infected by rhinovirus (RV). Alarmins, T2- and pro-inflammatory cytokines, IFNβ IFNλ, and viral load were analyzed by RT-qPCR and multiplex ELISA before and after stimulation.

RESULTS

IL-33 expression in unstimulated BECs and IL-33 protein levels in BALF were reduced after 12 weeks of tezepelumab. Further, IL-33 gene and protein levels decreased in BECs challenged with poly(I:C) after tezepelumab whereas TSLP gene expression remained unaffected. Poly(I:C)-induced IL-4, IL-13, and IL-17A release from BECs was also reduced with tezepelumab whereas IFNβ and IFNλ expression and viral load were unchanged.

CONCLUSION

Blocking TSLP with tezepelumab in vivo in asthma reduced the airway epithelial inflammatory response including IL-33 and T2 cytokines to viral challenge without affecting anti-viral host resistance. Our results suggest that blocking TSLP stabilizes the bronchial epithelial immune response to respiratory viruses.

Fabrication of Insoluble Elastin by Enzyme-Free Cross-Linking

Elastin is an essential extracellular matrix protein that enables tissues and organs such as arteries, lungs, and skin, which undergo continuous deformation, to stretch and recoil. Here, an approach to fabricating artificial elastin with close-to-native molecular and mechanical characteristics is described. Recombinantly produced tropoelastin are polymerized through coacervation and allysine-mediated cross-linking induced by pyrroloquinoline quinone (PQQ). A technique that allows the recovery and repeated use of PQQ for protein cross-linking by covalent attachment to magnetic Sepharose beads is developed. The produced material closely resembles natural elastin in its molecular, biochemical, and mechanical properties, enabled by the occurrence of the cross-linking amino acids desmosine, isodesmosine, and merodesmosine. It possesses elevated resistance against tryptic proteolysis, and its Young's modulus ranging between 1 and 2 MPa is similar to that of natural elastin. The approach described herein enables the engineering of mechanically resilient, elastin-like materials for biomedical applications.

Sustained growth factor delivery from bioactive PNIPAM-grafted-chitosan/heparin multilayers as a tool to promote growth and migration of cells

Delivery of growth factors (GFs) is challenging for regulation of cell proliferation and differentiation due to their rapid inactivation under physiological conditions. Here, a bioactive polyelectrolyte multilayer (PEM) is engineered by the combination of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and glycosaminoglycans to be used as reservoir for GF storage. PNIPAM-grafted-chitosan (PChi) with two degrees of substitution (DS) are synthesized, namely LMW* (DS 0.14) and HMW (DS 0.03), by grafting low (2 kDa) and high (10 kDa) molecular weight of PNIPAM on the backbone of chitosan (Chi) to be employed as polycations to form PEM with the polyanion heparin (Hep) at pH 4. Subsequently, PEMs are chemically crosslinked to improve their stability at physiological pH 7.4. Resulting surface and mechanical properties indicate that PEM containing HMW is responsive to temperature at 20 °C and 37 °C, while LMW is not. More importantly, Hep as terminal layer combined with HMW allows not only a better retention of the adhesive protein vitronectin but also a sustained release of FGF-2 at 37 °C. With the synergistic effect of vitronectin and matrix-bound FGF-2, significant promotion on adhesion, proliferation, and migration of 3T3 mouse embryonic fibroblasts is achieved on HMW-containing PEM compared to Chi-containing PEM and exogenously added FGF-2. Thus, PEM containing PNIPAM in combination with bioactive glycosaminoglycans like Hep represents a versatile approach to fabricate a GF delivery system for efficient cell culture, which can be potentially served as cell culture substrate for production of (stem) cells and bioactive wound dressing for tissue regeneration.

Nano-CT characterization of dentinal tubule occlusion in SDF-treated dentin

Dentin hypersensitivity is an oral health concern affecting a large percentage of the world's adult population. Occlusion of the exposed dentinal tubules is among the treatment options available, and silver diammine fluoride (SDF) is an occluding agent used for interrupting or dampening the stimulus of the dental pulp nerves that produce pain. In addition to dentin permeability testing, the evaluation of desensitizing agents occluding dentinal tubules strongly relies on microscopic techniques, such as scanning electron microscopy (SEM). Limitations of SEM are that it provides only surface images that lack detailed information on the depth of penetration and amount of material present within the treated specimen, and it is prone to sample preparation artifacts. Here, we present high-resolution X-ray computed tomography (nano-CT) as a potential method for investigating dentin specimens with occluded tubules. We studied human dentin treated with SDF as an exemplary dentinal occlusion treatment option. We evaluated the silver deposits formed on the dentin surface region near the dentinal tubules and in the tubular regions using cross-section SEM, Energy Dispersive X-ray (EDX) analysis, and nano-CT. The resulting images obtained by SEM and nano-CT had comparable resolutions, and both techniques produced images of the tubules' occlusion. Nano-CT provided three-dimensional images adequate to quantitate tubule size and orientation in space. Moreover, it enabled clear visualization of dentinal tubules in any virtual plane and estimation of the amount and depth of occluding material. Thus, nano-CT has the potential to be a valuable technique for evaluating the occluding effects of virtually any material applied to dentinal tubules, supporting deciding between the best occluding treatment options.

Lipoplex-Functionalized Thin-Film Surface Coating Based on Extracellular Matrix Components as Local Gene Delivery System to Control Osteogenic Stem Cell Differentiation

A gene-activated surface coating is presented as a strategy to design smart biomaterials for bone tissue engineering. The thin-film coating is based on polyelectrolyte multilayers composed of collagen I and chondroitin sulfate, two main biopolymers of the bone extracellular matrix, which are fabricated by layer-by-layer assembly. For further functionalization, DNA/lipid-nanoparticles (lipoplexes) are incorporated into the multilayers. The polyelectrolyte multilayer fabrication and lipoplex deposition are analyzed by surface sensitive analytical methods that demonstrate successful thin-film formation, fibrillar structuring of collagen, and homogenous embedding of lipoplexes. Culture of mesenchymal stem cells on the lipoplex functionalized multilayer results in excellent attachment and growth of them, and also, their ability to take up cargo like fluorescence-labelled DNA from lipoplexes. The functionalization of the multilayer with lipoplexes encapsulating DNA encoding for transient expression of bone morphogenetic protein 2 induces osteogenic differentiation of mesenchymal stem cells, which is shown by mRNA quantification for osteogenic genes and histochemical staining. In summary, the novel gene-functionalized and extracellular matrix mimicking multilayer composed of collagen I, chondroitin sulfate, and lipoplexes, represents a smart surface functionalization that holds great promise for tissue engineering constructs and implant coatings to promote regeneration of bone and other tissues.

Evaluation of the Temple Touch Pro™ noninvasive core-temperature monitoring system in 100 adults under general anesthesia: a prospective comparison with esophageal temperature

Perioperative hypothermia is still common and has relevant complication for the patient. An effective perioperative thermal management requires essentially an accurate method to measure core temperature. So far, only one study has investigated the new Temple Touch Pro™ (Medisim Ltd., Beit-Shemesh, Israel). during anesthesia Therefore, we assessed the agreement between the Temple Touch Pro™ thermometer (TTP) and distal esophageal temperature (T_Eso) in a second study. After approval by the local ethics committee we studied 100 adult patients undergoing surgery with general anesthesia. Before induction of anesthesia the TTP sensor unit was attached to the skin above the temporal artery. After induction of anesthesia an esophageal temperature probe was placed in the distal esophagus. Recordings started 10 min after placement of the esophageal temperature probe to allow adequate warming of the probes. Pairs of temperature values were documented in five-minute intervals until emergence of anesthesia. Accuracy of the two methods was assessed by Bland-Altman comparisons of differences with multiple measurements. Core temperatures obtained with the TTP in adults showed a mean bias of -0.04 °C with 95% limits of agreement within - 0.99 °C to + 0.91 °C compared to an esophageal temperature probe. We consider the TTP as a reasonable tool for perioperative temperature monitoring. It is not accurate enough to be used as a reference method in scientific studies, but may be a useful tool especially for conscious patients undergoing neuraxial anesthesia or regional anesthesia with sedation. Trial registration This study was registered in the German Clinical Trials Register (DRKS-ID: 00024050), day of registration 12/01/2021.

Hemoadsorption in the critically ill-Final results of the International CytoSorb Registry

The aim of the current paper is to summarize the results of the International CytoSorb Registry. Data were collected on patients of the intensive care unit. The primary endpoint was actual in-hospital mortality compared to the mortality predicted by APACHE II score. The main secondary endpoints were SOFA scores, inflammatory biomarkers and overall evaluation of the general condition. 1434 patients were enrolled. Indications for hemoadsorption were sepsis/septic shock (N = 936); cardiac surgery perioperatively (N = 172); cardiac surgery postoperatively (N = 67) and "other" reasons (N = 259). APACHE-II-predicted mortality was 62.0±24.8%, whereas observed hospital mortality was 50.1%. Overall SOFA scores did not change but cardiovascular and pulmonary SOFA scores decreased by 0.4 [-0.5;-0.3] and -0.2 [-0.3;-0.2] points, respectively. Serum procalcitonin and C-reactive protein levels showed significant reduction: -15.4 [-19.6;-11.17] ng/mL; -17,52 [-70;44] mg/L, respectively. In the septic cohort PCT and IL-6 also showed significant reduction: -18.2 [-23.6;-12.8] ng/mL; -2.6 [-3.0;-2.2] pg/mL, respectively. Evaluation of the overall effect: minimal improvement (22%), much improvement (22%) and very much improvement (10%), no change observed (30%) and deterioration (4%). There was no significant difference in the primary outcome of mortality, but there were improvements in cardiovascular and pulmonary SOFA scores and a reduction in PCT, CRP and IL-6 levels. Trial registration: ClinicalTrials.gov Identifier: NCT02312024 (retrospectively registered).

Insights into Inner Ear Function and Disease Through Novel Visualization of the Ductus Reuniens, a Seminal Communication Between Hearing and Balance Mechanisms

The sensory end-organs responsible for hearing and balance in the mammalian inner ear are connected via a small membranous duct known as the ductus reuniens (also known as the reuniting duct (DR)). The DR serves as a vital nexus linking the hearing and balance systems by providing the only endolymphatic connection between the cochlea and vestibular labyrinth. Recent studies have hypothesized new roles of the DR in inner ear function and disease, but a lack of knowledge regarding its 3D morphology and spatial configuration precludes testing of such hypotheses. We reconstructed the 3D morphology of the DR and surrounding anatomy using osmium tetroxide micro-computed tomography and digital visualizations of three human inner ear specimens. This provides a detailed, quantitative description of the DR's morphology, spatial relationships to surrounding structures, and an estimation of its orientation relative to head position. Univariate measurements of the DR, inner ear, and cranial planes were taken using the software packages 3D Slicer and Zbrush. The DR forms a narrow, curved, flattened tube varying in lumen size, shape, and wall thickness, with its middle third being the narrowest. The DR runs in a shallow bony sulcus superior to the osseus spiral lamina and adjacent to a ridge of bone that we term the "crista reuniens" oriented posteromedially within the cranium. The DR's morphology and structural configuration relative to surrounding anatomy has important implications for understanding aspects of inner ear function and disease, particularly after surgical alteration of the labyrinth and potential causative factors for Ménière's disease.

Metal Ion Doping of Alginate-Based Surface Coatings Induces Adipogenesis of Stem Cells

Metal ions are important effectors of protein and cell functions. Here, polyelectrolyte multilayers (PEMs) made of chitosan (Chi) and alginate (Alg) were doped with different metal ions (Ca²⁺, Co²⁺, Cu²⁺, and Fe³⁺), which can form bonds with their functional groups. Ca²⁺ and Fe³⁺ ions can be deposited in PEM at higher quantities resulting in more positive ζ potentials and also higher water contact angles in the case of Fe³⁺. An interesting finding was that the exposure of PEM to metal ions decreases the elastic modulus of PEM. Fourier transformed infrared (FTIR) spectroscopy of multilayers provides evidence of interaction of metal ions with the carboxylic groups of Alg but not for hydroxyl and amino groups. The observed changes in wetting and surface potential are partly related to the increased adhesion and proliferation of multipotent C3H10T1/2 fibroblasts in contrast to plain nonadhesive [Chi/Alg] multilayers. Specifically, PEMs doped with Cu²⁺ and Fe³⁺ ions greatly promote cell attachment and adipogenic differentiation, which indicates that changes in not only surface properties but also the bioactivity of metal ions play an important role. In conclusion, metal ion-doped multilayer coatings made of alginate and chitosan can promote the differentiation of multipotent cells on implants without the use of other morphogens like growth factors.

Dentin tubule occlusion by a 38% silver diamine fluoride gel: an in vitro investigation

Objective

Silver diamine fluoride (SDF) is effective in treatment of dentin hypersensitivity and caries lesions. However, the non-viscous solution does not easily allow clinicians to control the application area. A 38% SDF experiment gel was compared in vitro to commercial SDF for its ability to penetrate and occlude dentinal tubules.

Materials and methods

Human root surface dentin specimens were treated with gelled or standard 38% SDF or negative control. Penetration behavior was established by Drop Shape Analysis. Precipitates at the surface and within tubules were analyzed by SEM and EDX after treatment; Results: penetration depths up to 500 µm were observed for both SDF formulations. Both formulations occluded dentinal tubules similarly. Precipitates on the dentin surface and within dentinal tubules were found for both SDF formulations, with a slight tendency for the experimental gel SDF product to be more abundant than the commercially available one. Discussion: behavior of the experimental 38% SDF gel formulation appeared indistinguishable from the commercial 38% SDF product with respect to dentinal tubule penetration and occlusion.

Conclusions

The experimental 38% SDF gel may be a suitable intervention for the prevention of dentin hypersensitivity.

Microimaging of a novel intracochlear drug delivery device in combination with cochlear implants in the human inner ear

The effective delivery of drugs to the inner ear is still an unmet medical need. Local controlled drug delivery to this sensory organ is challenging due to its location in the petrous bone, small volume, tight barriers, and high vulnerability. Local intracochlear delivery of drugs would overcome the limitations of intratympanic (extracochlear) and systemic drug application. The requirements for such a delivery system include small size, appropriate flexibility, and biodegradability. We have developed biodegradable PLGA-based implants for controlled intracochlear drug release that can also be used in combination with cochlear implants (CIs), which are implantable neurosensory prosthesis for hearing rehabilitation. The drug carrier system was tested for implantation in the human inner ear in 11 human temporal bones. In five of the temporal bones, CI arrays from different manufacturers were implanted before insertion of the biodegradable PLGA implants. The drug carrier system and CI arrays were implanted into the scala tympani through the round window. Implanted temporal bones were evaluated by ultra-high-resolution computed tomography (µ-CT) to illustrate the position of implanted electrode carriers and the drug carrier system. The µ-CT measurements revealed the feasibility of implanting the PLGA implants into the scala tympani of the human inner ear and co-administration of the biodegradable PLGA implant with a CI array.

Cerosomes as skin repairing agent: Mode of action studies with a model stratum corneum layer at liquid/air and liquid/solid interfaces

The stratum corneum (SC) is the largest physical barrier of the human body. It protects against physical, chemical and biological damages, and avoids evaporation of water from the deepest skin layers. For its correct functioning, the homeostasis of the SC lipid matrix is fundamental. An alteration of the lipid matrix composition and in particular of its ceramide (CER) fraction can lead to the development of pathologies such as atopic dermatitis and psoriasis. Different studies showed that the direct replenishment of SC lipids on damaged skin had positive effects on the recovery of its barrier properties. In this work, cerosomes, i.e. liposomes composed of SC lipids, have been successfully prepared in order to investigate the mechanism of interaction with a model SC lipid matrix. The cerosomes contain CER[NP], D-CER[AP], stearic acid and cholesterol. In addition, hydrogenated soybean phospholipids have been added to one of the formulations leading to an increased stability at neutral pH. For the mode of action studies, monolayer models at the air-water interface and on solid support have been deployed. The results indicated that a strong interaction occurred between SC monolayers and the cerosomes. Since both systems were negatively charged, the driving force for the interaction must be based on the ability of CERs head groups to establish intermolecular hydrogen bonding networks that energetically prevailed against the electrostatic repulsion. This work proved for the first time the mode of action by which cerosomes exploit their function as skin barrier repairing agents on the SC.

Effect of metal ions on the physical properties of multilayers from hyaluronan and chitosan, and the adhesion, growth and adipogenic differentiation of multipotent mouse fibroblasts

Polyelectrolyte multilayers (PEMs) consisting of the polysaccharides hyaluronic acid (HA) as the polyanion and chitosan (Chi) as the polycation were prepared with layer-by-layer technique (LbL). The [Chi/HA]₅ multilayers were exposed to solutions of metal ions (Ca²⁺, Co²⁺, Cu²⁺ and Fe³⁺). Binding of metal ions to [Chi/HA]₅ multilayers by the formation of complexes with functional groups of polysaccharides modulates their physical properties and the bioactivity of PEMs with regard to the adhesion and function of multipotent murine C3H10T1/2 embryonic fibroblasts. Characterization of multilayer formation and surface properties using different analytical methods demonstrates changes in the wetting, surface potential and mechanical properties of multilayers depending on the concentration and type of metal ion. Most interestingly, it is observed that Fe³⁺ metal ions greatly promote adhesion and spreading of C3H10T1/2 cells on the low adhesive [Chi/HA]₅ PEM system. The application of intermediate concentrations of Cu²⁺, Ca²⁺ and Co²⁺ as well as low concentrations of Fe³⁺ to PEMs also results in increased cell spreading. Moreover, it can be shown that complex formation of PEMs with Cu²⁺ and Fe³⁺ ions leads to increased metabolic activity in cells after 24 h and induces cell differentiation towards adipocytes in the absence of any additional adipogenic media supplements. Overall, complex formation of [Chi/HA]₅ PEM with metal ions like Cu²⁺ and Fe³⁺ represents an interesting and cheap alternative to the use of growth factors for making cell-adhesive coatings and guiding stem cell differentiation on implants and scaffolds to regenerate connective-type of tissues.

Engineering osteogenic microenvironments by combination of multilayers from collagen type I and chondroitin sulfate with novel cationic liposomes

Cationic liposomes composed of a novel lipid (N-{6-amino-1-[N-(9Z) -octadec9-enylamino] -1-oxohexan-(2S) -2-yl} -N'- {2- [N, N-bis(2-aminoethyl) amino] ethyl} -2-hexadecylpropandiamide) (OO4) and dioleoylphosphatidylethanolamine (DOPE) possess high amounts of amino groups and are promising systems for lipofection. Moreover, these cationic liposomes can also be used as a polycationic entity in multilayer formation using layer-by-layer technique (LbL), which is a method to fabricate surface coatings by alternating adsorption of polyanions and polycations. Since liposomes are suitable for endocytosis by or fusion with cells, controlled release of their cargo on site is possible. Here, a polyelectrolyte multilayer (PEM) system was designed of chondroitin sulfate (CS) and collagen type I (Col I) by LbL technique with OO4/DOPE liposomes embedded in the terminal layers to create an osteogenic microenvironment. Both, the composition of PEM and cargo of the liposomes were used to promote osteogenic differentiation of C2C12 myoblasts as in vitro model. The internalization of cargo-loaded liposomes from the PEM into C2C12 cells was studied using lipophilic (Rhodamine-DOPE conjugate) and hydrophilic (Texas Red-labeled dextran) model compounds. Besides, the use of Col I and CS should mimic the extracellular matrix of bone for future applications such as bone replacement therapies. Physicochemical studies of PEM were done to characterize the layer growth, thickness, and topography. The adhesion of myoblast cells was also evaluated whereby the benefit of a cover layer of CS and finally Col I above the liposome layer was demonstrated. As proof of concept, OO4/DOPE liposomes were loaded with dexamethasone, a compound that can induce osteogenic differentiation. A successful induction of osteogenic differentiation of C2C12 cells with the novel designed liposome-loaded PEM system was shown. These findings indicate that designed OH4/DOPE loaded PEMs have a high potential to be used as drug delivery or transfection system for implant coating in the field of bone regeneration and other applications.

Short interruptions between pre-warming and intraoperative warming are associated with low intraoperative hypothermia rates

BACKGROUND

Prevention of inadvertent hypothermia is recommended for procedures >30 minutes because hypothermia increases the risk of myocardial ischemia, intraoperative blood loss, transfusion and wound complications. Therefore, short warming interruptions between pre-warming and intraoperative warming might result in lower hypothermia rates. The aim of this retrospective investigation was to determine whether the incidence of inadvertent intraoperative hypothermia was affected by the warming interruption.

METHODS

The lowest intraoperative body core temperature value and the warming interruption time were taken from anaesthesia records. Body core temperature was recorded continuously, and a patient was classified to be hypothermic if the lowest recorded temperature value was <36°C. Hypothermia rates and the correlation between warming interruption times and intraoperative hypothermia rates were calculated.

RESULTS

Five thousand eighty-four patients were analysed. The intraoperative hypothermia rate was 15.3%. Nineteen patients (0.4%) had a recorded temperature of <35.0°C. An increase in forced-air warming interruption time was significantly associated with an increase in intraoperative hypothermia rates (P < .0001). Patients with interruptions in forced-air warming >20 minutes showed significantly higher hypothermia rates than those with interruptions of ≤20 minutes (P < .0001).

CONCLUSION

Intraoperative hypothermia rates increased significantly with longer forced-air warming interruptions between pre-warming and intraoperative warming. Short warming interruptions can preserve the effect of pre-warming and are associated with low intraoperative hypothermia rates.

Two genes in a pathogenicity gene cluster encoding secreted proteins are required for appressorial penetration and infection of the maize anthracnose fungus Colletotrichum graminicola

To avoid pathogen-associated molecular pattern recognition, the hemibiotrophic maize pathogen Colletotrichum graminicola secretes proteins mediating the establishment of biotrophy. Targeted deletion of 26 individual candidate genes and seven gene clusters comprising 32 genes of C. graminicola identified a pathogenicity cluster (CLU5) of five co-linear genes, all of which, with the exception of CLU5b, encode secreted proteins. Targeted deletion of all genes of CLU5 revealed that CLU5a and CLU5d are required for full appressorial penetration competence, with virulence deficiencies independent of the host genotype and organ inoculated. Cytorrhysis experiments and microscopy showed that Δclu5a mutants form pressurized appressoria, but they are hampered in forming penetration pores and fail to differentiate a penetration peg. Whereas Δclu5d mutants elicited WT-like papillae, albeit at increased frequencies, papillae induced by Δclu5a mutants were much smaller than those elicited by the WT. Synteny of CLU5 is not only conserved in Colletotrichum spp. but also in additional species of Sordariomycetes including insect pathogens and saprophytes suggesting importance of CLU5 for fungal biology. Since CLU5a and CLU5d also occur in non-pathogenic fungi and since they are expressed prior to plant invasion and even in vegetative hyphae, the encoded proteins probably do not act primarily as effectors.

Cyclic Redox-Mediated Switching of Surface Properties of Thiolated Polysaccharide Multilayers and Its Effect on Fibroblast Adhesion

Advanced technologies for controlled cell adhesion and detachment in novel biointerface designs profit from stimuli-responsive systems that are able to react to their environment. Here, a multilayer system made of thiolated chitosan and thiolated chondroitin sulfate was constructed, with the potential of switchable inter- and intramolecular thiol/disulfide interactions representing a redox-sensitive nanoplatform. Owing to the formation and cleavage of inherent disulfide bonds by oxidation and reduction, surface properties of the multilayer can be controlled toward protein adsorption/desorption and cell adhesion in a reversible manner. Oxidation of thiols by chloramine-T promotes fibronectin (FN) adsorption and fibroblast cell adhesion, whereas the reduction by tris(2-carboxyethyl)phosphine reverses these effects, leading to low FN adsorption and little cell adhesion and spreading. These effects on the biological systems are related to significant changes of wetting properties, zeta potential, and mechanical properties of these multilayer films. The system presented may be useful for biomedical applications as responsive and obedient surfaces in medical implants and support tissue regeneration.

House dust mite impairs antiviral response in asthma exacerbation models through its effects on TLR3

BACKGROUND

Impaired antiviral interferon expression may be involved in asthma exacerbations commonly caused by rhinovirus infections. Allergy is a known risk factor for viral-induced asthma exacerbation, but little is known whether allergens may affect interferon responses.

OBJECTIVE

Our hypothesis is that house dust mite (HDM) impairs viral stimulus-induced antiviral signalling.

METHODS

Experimental asthma exacerbations were produced in vitro in human bronchial epithelial cells (HBECs) and in mice using sequential challenges with HDM and a viral infection mimic, Poly(I:C). We examined rhinovirus pattern recognition receptors (PRRs) signalling pathways and potential mechanisms of impaired interferon response.

RESULTS

HBECs and mice exposed to HDM prior to Poly(I:C) exhibited a reduced antiviral response compared to Poly(I:C) alone, including reduced IFN-β, IFN-λ, TLR3, RIG-I, MDA5, IRF-3 and IRF-7. Heat inactivation of HDM partially restored the TLR3-induced interferon response in vitro and in vivo. Our HBEC-data further showed that HDM directly affects TLR3 signalling by targeting the receptor glycosylation level.

CONCLUSIONS

Direct effects of allergens such as HDM on PRRs can present as potential mechanism for defective antiviral airway responses. Accordingly, therapeutic measures targeting inhibitory effects of allergens on antiviral PRRs may find use as a strategy to boost antiviral response and ameliorate exacerbations in asthmatic patients.

[Intrahepatic cholangiocarcinoma : Results after 84 resections]

BACKGROUND

The incidence of intrahepatic cholangiocarcinoma (ICC) is increasing worldwide. Surgical resection is the only curative treatment option.

AIM OF THE STUDY

This study analyzed the prognostic factors after resection of ICC.

MATERIAL AND METHODS

A total of 84 patients were surgically treated under potentially curative intent. Perihilar and distal cholangiocarcinomas were excluded. The 5‑year survival was analyzed with respect to tumor stage (TNM), number of lesions, complete surgical resection (R0), peritoneal carcinosis and postoperative complications.

RESULTS

The 5‑year survival was 27% and 77% of patients underwent R0 resections. In the univariate analysis a T stage >2, an N+ situation or an R+ resection as well as peritoneal and multilocular intrahepatic spread were associated with a poorer prognosis. Postoperative complications also negatively influenced survival. On multivariate analysis the absence of peritoneal spread, node-negative tumor stages, singular hepatic lesions and a low T stage as well as the absence of complications were associated with improved survival.

DISCUSSION

The prognosis of ICC is poor even after successful surgical resection. Well-known tumor characteristics such as TNM are relevant prognostic factors. Surgical resection is accompanied by postoperative complications (most frequently biliary), which negatively influence survival. Adjuvant strategies are urgently needed to improve long-term survival even after complete surgical resection.

Stimuli-Responsive Multilayers Based on Thiolated Polysaccharides That Affect Fibroblast Cell Adhesion

Control of the biomaterial properties through stimuli-responsive polymeric platforms has become an essential technique in recent biomedical applications. A multilayer system of thiolated chitosan (t-Chi) and thiolated chondroitin sulfate (t-CS), consisting of five double layers ([t-Chi/t-CS]₅), was fabricated here by applying a layer-by-layer coating strategy. To represent a novel class of chemically tunable nanostructures, the ability to cross-link pendant thiol groups was tested by a rise from pH 4 during layer formation to pH 9.3 and a more powerful chemical stimulus by using chloramine-T (ChT). Following both treatments, the resulting multilayers showed stimuli-dependent behavior, as demonstrated by their content of free thiols, wettability, surface charge, elastic modulus, roughness, topography, thickness, and binding of fibronectin. Studies with human dermal fibroblasts further demonstrated the favorable potential of the ChT-responsive multilayers as a cell-adhesive surface compared to pH-induced cross-linking. Because the [t-Chi/t-CS]₅ multilayer system is responsive to stimuli such as the pH and redox environment, multilayer systems with disulfide bond formation may help to tailor their interaction with cells, film degradation, and controlled release of bioactive substances like growth factors in a stimuli-responsive manner useful in future wound healing and tissue engineering applications.

Cross-linking multilayers of poly-l-lysine and hyaluronic acid: Effect on mesenchymal stem cell behavior

BACKGROUND

Cells possess a specialized machinery through which they can sense physical as well as chemical alterations in their surrounding microenvironment that affect their cellular behavior.

AIM

In this study, we aim to establish a polyelectrolyte multilayer system of 24 layers of poly-l-lysine and hyaluronic acid to control stem cell response after chemical cross-linking.

METHODS AND RESULTS

The multilayer build-up process is monitored using different methods, which show that the studied polyelectrolyte multilayer system grows exponentially following the islands and islets theory. Successful chemical cross-linking is monitored by an increased zeta potential toward negative magnitude and an extraordinary growth in thickness. Human adipose-derived stem cells are used here and a relationship between cross-linking degree and cell spreading is shown as cells seeded on higher cross-linked polyelectrolyte multilayer show enhanced spreading. Furthermore, cells that fail to establish focal adhesions on native and low cross-linked polyelectrolyte multilayer films do not proliferate to a high extent in comparison to cells seeded on highly cross-linked polyelectrolyte multilayer, which also show an increased metabolic activity. Moreover, this study shows the relation between cross-linking degree and human adipose-derived stem cell lineage commitment. Histological staining reveals that highly cross-linked polyelectrolyte multilayers support osteogenic differentiation, whereas less cross-linked and native polyelectrolyte multilayers support adipogenic differentiation in the absence of any specific inducers.

CONCLUSION

Owing to the precise control of polyelectrolyte multilayer properties such as potential, wettability, and viscoelasticity, the system presented here offers great potential for guided stem cell differentiation in regenerative medicine, especially in combination with materials exhibiting a defined surface topography.

Bone-conditioned medium modulates the osteoconductive properties of collagen membranes in a rat calvaria defect model

OBJECTIVES

Collagen membranes are not limited to be occlusive barriers as they actively support bone regeneration. However, the impact of bone-derived growth factors on their osteoconductive competence has not been examined.

METHODS

Twenty adult Sprague Dawley rats were included in the study. Calvaria defects with a diameter of five millimeter were created. The defect was covered with one layer of a collagen membrane previously soaked in conditioned medium of porcine bone chips or in culture medium alone. After 4 weeks, microcomputed tomography was performed. Undecalcified thin-ground sections were subjected to light and scanning electron microscopy. Primary outcome parameter was the bone volume in the defect. Unit of analysis was the bone-conditioned medium (BCM).

RESULTS

In the central defect area of the control and the BCM group, median new bone connected to the host bone was 0.54 and 0.32 mm³, respectively (p = .10). In the ectocranial defect area, the control group showed significantly more bone than the BCM group (0.90 and 0.26 mm³; p = .02). Based on an exploratory interpretation, the control group had smaller bony islands than the BCM group. Scanning electron microscopy and histology indicate the formation of bone but also the collagen membrane to be mineralized in the defect site.

CONCLUSIONS

These results demonstrate that the commercial collagen membrane holds an osteoconductive competence in a rat calvaria defect model. Soaking collagen membranes with BCM shifts bone formation toward the formation of bony islands rather than new bone connected to the host bone.

Allergens produce serine proteases-dependent distinct release of metabolite DAMPs in human bronchial epithelial cells

BACKGROUND

The respiratory epithelium is a major site for disease interaction with inhaled allergens. Additional to IgE-dependent effects, allergens contain proteases that may stimulate human bronchial epithelial cells (HBECs) through protease-activated receptors, causing the release of mediators important in driving Th2-mediated immune responses.

OBJECTIVE

We aimed to investigate whether different allergens induce metabolite DAMPs such as ATP and uric acid (UA) release in HBECs.

METHODS

HBECs (BEAS-2B cell line) were exposed to different allergen extracts; house dust mite (HDM), Alternaria alternata, Artemisia vulgaris and Betula pendula and UA, ATP, IL-8 and IL-33 release were measured. Allergen extracts were heat-inactivated or pre-incubated with serine (AEBSF) or cysteine (E64) protease inhibitors to study the involvement of protease activity in ATP, UA and IL-8 release. HDM-induced release of UA was studied in a mouse model of allergic inflammation.

RESULTS

All allergens caused dose-dependent rapid release of ATP and IL-8, but only HDM induced UA release from HBECs. HDM also caused release of UA in vivo in our mouse model of allergic inflammation. ATP release by all 4 allergen extracts was significantly reduced by heat-inactivation and by serine protease inhibitors. Similarly, the HDM-induced UA release was also abrogated by heat-inactivation of HDM extract and dependent on serine proteases. Furthermore, allergen-induced IL-8 mRNA expression was inhibited by serine protease inhibitors.

CONCLUSIONS AND CLINICAL RELEVANCE

ATP was released by all 4 allergens in HBECs supporting the role of ATP involvement in asthma pathology. However, HDM stands out by its capacity to cause UA release, which is of interest in view of the proposed role of UA in early initiation of allergic asthma. Although serine proteases may be involved in the activity of all the studied allergens, further work is warranted to explain the differences between HDM and the other 3 allergens regarding the effects on UA release.

Reduced Lateral Confinement and Its Effect on Stability in Patterned Strong Polyelectrolyte Brushes

The stability of strong polyelectrolyte brushes (PEBs) was studied in bulk and in patterned structures. Thick PEBs of poly([(2-methacryloyloxy)ethyl]trimethylammonium chloride) with thicknesses >100 nm were synthesized using single electron transfer living radical polymerization. Brush patterning was identified using deep-ultraviolet photolithography by means of either a top-down (TD) or bottom-up (BU) method, with features as small as 200 nm. The brushes were soaked in water under a range of pH or temperature conditions, and the hydrolysis was monitored through dry-state ellipsometry and atomic force microscopy measurements. BU patterns showed reduced degrafting for smaller patterns, which was attributed to increased stress relaxation at such dimensions. In contrast to the already relaxed BU-patterned brush, a TD-patterned brush possesses perpendicular structures that result from the use of orthogonal lithography. It was found that the TD process induces cross-linking on the sidewall, which subsequently fortifies the sidewall materials. This modification of the polymer brushes hindered the stress relaxation of the patterns, and the degrafting trends became irrelevant to the pattern sizes. With proper tuning, the cross-linking on the sidewall was minimized and the degrafting trends were again relaxation-dependent.

INTERRELATIONS BETWEEN MORPHOLOGY AND SOFTENING BEHAVIOR IN SELF-ASSEMBLED POLY (BUTADIENE-BLOCK-(STYRENE-STAT-BUTADIENE)) COPOLYMERS

Two series of poly(butadiene-block-(styrene-stat-butadiene) (PB-SBR) diblock copolymers were synthesized to study interrelations between microphase-separated state and relaxation dynamics. Series I consists of six symmetric PB-SBR samples (ΦSBR ∼ 0.50) with different styrene contents in the random SBR block (21 mol% ≤ xS,SBR ≤ 52 mol%). Series II contains six asymmetric PB-SBR diblock copolymers with almost constant styrene content in the SBR block (xS,SBR = 32 ± 4 mol%) and SBR volume fractions in the range of 0.20 ≤ ΦSBR ≤ 0.69. All PB-SBR diblock copolymers have a total molecular weight of about 200 kg/mol with 1,2-vinyl content of about 8.5 and 15.8 mol% in the soft PB and in the hard SBR block, respectively. A novel synthesis route has been developed so as to maintain low 1,2-vinyl contents in both blocks and a random distribution of the styrene units in the SBR block. The softening behavior of non–cross-linked PB-SBR diblocks was investigated by differential scanning calorimetry, providing first information about miscibility. The morphology of cross-linked PB-SBR diblock copolymers, which have been vulcanized with sulfur at 150 °C using standard procedures, was studied by atomic force microscopy. Dynamic shear measurements aimed at understanding the influence of morphological changes on the segmental dynamics of both phases, αPB and αSBR, were performed on vulcanized samples. Atomic force microscopy results and shear data indicate that symmetric diblock copolymers with styrene content higher than 27 mol% in the SBR block are well microphase separated. Strongly segregated states are also observed for asymmetric diblock copolymers with volume fractions 0.28 ≤ ΦSBR ≤ 0.60 showing cylindrical and lamellar morphologies. The origin of changes in the αPB and αSBR dynamics depending on morphology and segregation strengths is considered. Implications for the use of rubbery PB-SBR block copolymers in composites for tire treads are discussed.

A Jones matrix formalism for simulating three-dimensional polarized light imaging of brain tissue

The neuroimaging technique three-dimensional polarized light imaging (3D-PLI) provides a high-resolution reconstruction of nerve fibres in human post-mortem brains. The orientations of the fibres are derived from birefringence measurements of histological brain sections assuming that the nerve fibres—consisting of an axon and a surrounding myelin sheath—are uniaxial birefringent and that the measured optic axis is oriented in the direction of the nerve fibres (macroscopic model). Although experimental studies support this assumption, the molecular structure of the myelin sheath suggests that the birefringence of a nerve fibre can be described more precisely by multiple optic axes oriented radially around the fibre axis (microscopic model). In this paper, we compare the use of the macroscopic and the microscopic model for simulating 3D-PLI by means of the Jones matrix formalism. The simulations show that the macroscopic model ensures a reliable estimation of the fibre orientations as long as the polarimeter does not resolve structures smaller than the diameter of single fibres. In the case of fibre bundles, polarimeters with even higher resolutions can be used without losing reliability. When taking the myelin density into account, the derived fibre orientations are considerably improved.

A setup for synchrotron-radiation-induced total reflection X-ray fluorescence and X-ray absorption near-edge structure recently commissioned at BESSY II BAMline

An automatic sample changer chamber for total reflection X-ray fluorescence (TXRF) and X-ray absorption near-edge structure (XANES) analysis in TXRF geometry was successfully set up at the BAMline at BESSY II. TXRF and TXRF-XANES are valuable tools for elemental determination and speciation, especially where sample amounts are limited (<1 mg) and concentrations are low (ng ml(-1) to µg ml(-1)). TXRF requires a well defined geometry regarding the reflecting surface of a sample carrier and the synchrotron beam. The newly installed chamber allows for reliable sample positioning, remote sample changing and evacuation of the fluorescence beam path. The chamber was successfully used showing accurate determination of elemental amounts in the certified reference material NIST water 1640. Low limits of detection of less than 100 fg absolute (10 pg ml(-1)) for Ni were found. TXRF-XANES on different Re species was applied. An unknown species of Re was found to be Re in the +7 oxidation state.

Self-assembled structure and relaxation dynamics of diblock copolymers made of polybutadiene and styrene/butadiene rubber

Interrelations between self-assembled structure and cooperative α dynamics are systematically studied based on two series of poly(butadiene-block-(styrene-stat-butadiene)) diblock copolymers.

Influence of the local atom configuration on a hexagonal skyrmion lattice

Spin-resolved scanning tunneling microscopy is used to reveal a commensurate hexagonal nanoskyrmion lattice in the hcp stacked Fe monolayer on Ir(111). The exact nature of the spin configuration is due to magnetic interactions between the Fe atoms and the Ir substrate, either originating from polarization effects, or due to a three-site hopping mechanism of the Dzyaloshinsky-Moriya interaction leading to a canting of the Dzyaloshinsky-Moriya vector with respect to the interface.

In planta production of ELPylated spidroin-based proteins results in non-cytotoxic biopolymers

BACKGROUND

Spider silk is a tear-resistant and elastic biopolymer that has outstanding mechanical properties. Additionally, exiguous immunogenicity is anticipated for spider silks. Therefore, spider silk represents a potential ideal biomaterial for medical applications. All known spider silk proteins, so-called spidroins, reveal a composite nature of silk-specific units, allowing the recombinant production of individual and combined segments.

RESULTS

In this report, a miniaturized spidroin gene, named VSO1 that contains repetitive motifs of MaSp1 has been synthesized and combined to form multimers of distinct lengths, which were heterologously expressed as elastin-like peptide (ELP) fusion proteins in tobacco. The elastic penetration moduli of layered proteins were analyzed for different spidroin-based biopolymers. Moreover, we present the first immunological analysis of synthetic spidroin-based biopolymers. Characterization of the binding behavior of the sera after immunization by competitive ELISA suggested that the humoral immune response is mainly directed against the fusion partner ELP. In addition, cytocompatibility studies with murine embryonic fibroblasts indicated that recombinant spidroin-based biopolymers, in solution or as coated proteins, are well tolerated.

CONCLUSION

The results show that spidroin-based biopolymers can induce humoral immune responses that are dependent on the fusion partner and the overall protein structure. Furthermore, cytocompatibility assays gave no indication of spidroin-derived cytotoxicity, suggesting that recombinant produced biopolymers composed of spider silk-like repetitive elements are suitable for biomedical applications.

Depression storage capacities of different ideal pavements as quantified by a terrestrial laser scanning-based method

Rainfall partition on paved urban surfaces is governed to a great extent by depression storage. This is especially the case for small rainfall events, which are often ignored in urban hydrology. If storage, infiltration and evaporation (important for urban heat island mitigation), rather than storm water run-off, are of interest, high-resolution simulations with exact values for depression storage capacities are required. Terrestrial laser scanners deliver fast, high-resolution surveys of pavement surface morphology. The depression storage capacity can be quantified from 3D points by generating digital elevation models and applying cut-and-fill algorithms in a geographic information system. The method was validated using a test model. It was possible to quantify depressions with a depth of at least 1.4 × 10(-3) m and a surface of at least 15 × 10(-6) m(2) with an uncertainty below 30%. Applying this method, the depression storage capacities for 11 ideal, typical pavement designs were found to vary from 0.07 to 1.4 mm. Realistic urban pavements must also be surveyed, as cracks and puddles from their use history can have a major impact on the depression storage capacities and thus on infiltration, evaporation and, finally, the annual run-off.

Molecular and ultrastructural analysis of forisome subunits reveals the principles of forisome assembly

BACKGROUND AND AIMS

Forisomes are specialized structural phloem proteins that mediate sieve element occlusion after wounding exclusively in papilionoid legumes, but most studies of forisome structure and function have focused on the Old World clade rather than the early lineages. A comprehensive phylogenetic, molecular, structural and functional analysis of forisomes from species covering a broad spectrum of the papilionoid legumes was therefore carried out, including the first analysis of Dipteryx panamensis forisomes, representing the earliest branch of the Papilionoideae lineage. The aim was to study the molecular, structural and functional conservation among forisomes from different tribes and to establish the roles of individual forisome subunits.

METHODS

Sequence analysis and bioinformatics were combined with structural and functional analysis of native forisomes and artificial forisome-like protein bodies, the latter produced by expressing forisome genes from different legumes in a heterologous background. The structure of these bodies was analysed using a combination of confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the function of individual subunits was examined by combinatorial expression, micromanipulation and light microscopy.

KEY RESULTS

Dipteryx panamensis native forisomes and homomeric protein bodies assembled from the single sieve element occlusion by forisome (SEO-F) subunit identified in this species were structurally and functionally similar to forisomes from the Old World clade. In contrast, homomeric protein bodies assembled from individual SEO-F subunits from Old World species yielded artificial forisomes differing in proportion to their native counterparts, suggesting that multiple SEO-F proteins are required for forisome assembly in these plants. Structural differences between Medicago truncatula native forisomes, homomeric protein bodies and heteromeric bodies containing all possible subunit combinations suggested that combinations of SEO-F proteins may fine-tune the geometric proportions and reactivity of forisomes.

CONCLUSIONS

It is concluded that forisome structure and function have been strongly conserved during evolution and that species-dependent subsets of SEO-F proteins may have evolved to fine-tune the structure of native forisomes.

Melanin is not required for turgor generation but enhances cell-wall rigidity in appressoria of the corn pathogen Colletotrichum graminicola

The ascomycete and causative agent of maize anthracnose and stem rot, Colletotrichum graminicola, differentiates melanized infection cells called appressoria that are indispensable for breaching the plant cell wall. High concentrations of osmolytes accumulate within the appressorium, and the internal turgor pressure of up to 5.4 MPa provides sufficient force to penetrate the leaf epidermis directly. In order to assess the function of melanin in C. graminicola appressoria, we identified and characterized the polyketide synthase 1 (CgPKS1) gene which displayed high similarity to fungal polyketide synthases (PKS) involved in synthesis of 1,3,6,8-tetrahydronaphthalene, the first intermediate in melanin biosynthesis. Cgpks1 albino mutants created by targeted gene disruption were unable to penetrate intact leaves and ruptured frequently but, surprisingly, were able to penetrate ultrathin polytetrafluoroethylene membranes mimicking the plant surface. Nonmelanized Cgpks1 appressoria were sensitive to externally applied cell-wall-degrading enzymes whereas melanized appressoria were not affected. Expression studies using a truncated CgPKS1 fused to green fluorescent protein revealed fluorescence in immature appressoria and in setae, which is in agreement with transcript data obtained by RNA-Seq and quantitative polymerase chain reaction. Unexpectedly, surface scans of mutant and wild-type appressoria revealed considerable differences in cell-wall morphology. Melanization of appressoria is indispensable for successful infection of intact leaves. However, cell collapse experiments and analysis of the appressorial osmolyte content by Mach-Zehnder interferometry convincingly showed that melanin is not required for solute accumulation and turgor generation, thus questioning the role of melanin as a barrier for osmolytes in appressoria of C. graminicola.

Transglutamination allows production and characterization of native-sized ELPylated spider silk proteins from transgenic plants

In the last two decades it was shown that plants have a great potential for production of specific heterologous proteins. But high cost and inefficient downstream processing are a main technical bottleneck for the broader use of plant-based production technology especially for protein-based products, for technical use as fibres or biodegradable plastics and also for medical applications. High-performance fibres from recombinant spider silks are, therefore, a prominent example. Spiders developed rather different silk materials that are based on proteins. These spider silks show excellent properties in terms of elasticity and toughness. Natural spider silk proteins have a very high molecular weight, and it is precisely this property which is thought to give them their strength. Transgenic plants were generated to produce ELPylated recombinant spider silk derivatives. These fusion proteins were purified by Inverse Transition Cycling (ITC) and enzymatically multimerized with transglutaminase in vitro. Layers produced by casting monomers and multimers were characterized using atomic force microscopy (AFM) and AFM-based nanoindentation. The layered multimers formed by mixing lysine- and glutamine-tagged monomers were associated with the highest elastic penetration modulus.

Parity effects in 120° spin spirals

The magnetic ground state of biatomic Fe chains on the reconstructed (5×1)-Ir(001) surface is a cycloidal 120° spin spiral. Spin-resolved scanning tunneling microscopy reveals a striking variation of magnetic field dependences among the chains, which we attribute to parity effects resulting from finite lengths. Numerical simulations show that the chains are divided in three symmetry classes with the exact number of atoms in the chain determining the size and direction of their net magnetic moment. In contrast to antiferromagnetic systems, the three-atom periodicity causes the effective anisotropy to alternate between out of plane, in plane, and quenched.

Uncertain role of MtSEO-F3 in assembly of Medicago truncatula forisomes

Forisomes are specialized multimeric protein complexes found only in the papilionoid legumes. They undergo a reversible conformational change in response to phloem injury to enable the occlusion of sieve tubes, thus preventing the loss of photoassimilates. The individual subunits are designated by the letters SEO-F (sieve element occlusion by forisomes) and are part of the larger SEO protein family, which also includes the typical P-proteins found in most dicots and some monocots. When specific SEO-F subunits from different species are expressed in a heterologous background, they self-assemble into fully-functional artificial forisomes. However, with the exception of basal species such as Dipteryx panamensis, the geometry of these artificial forisomes differs from that of their native counterparts. Studies involving SEO-F proteins from the model legume Medicago truncatula have shown that a combination of 3 of the 4 subunits can fine-tune the geometry of artificial forisomes. However, MtSEO-F3 was excluded from these studies because it was not incorporated into either the native or artificial forisomes in our original experiments. In this addendum, we present further data concerning the interactive properties of the SEO-F proteins and confirm that all 4 MtSEO-F proteins interact in all possible pairwise combinations. These data indicate that the exclusion of MtSEO-F3 from the compact forisome may reflect the steric hindrance of binding sites rather than an inability to interact with other forisome subunits.