Elevation of Tear MMP-9 Concentration as a Biomarker of Inflammation in Ocular Pathology by Antibody Microarray Immunodetection Assays

Matrix metalloproteinases are a family of enzymes fundamental in inflammatory processes. Between them, MMP-9 is up-regulated during inflammation; thus, its quantification in non-invasive fluids is a promising approach for inflammation identification. To this goal, a biomarker quantification test was developed for ocular inflammation detection using anti-MMP-9 antibody microarrays (AbMAs). After validation with eight healthy control tear samples characterized by ELISA, 20 samples were tested from individuals diagnosed with ocular inflammation due to: cataracts, glaucoma, meibomian gland dysfunction, allergy, or dry eye. Concentration values of tear MMP-9 were obtained for each sample, and 12 patients surpassed the pathological threshold (30 ng/mL). A significant elevation of MMP-9 concentration in the tears of glaucoma patients compared with healthy controls was observed. In order to evaluate the diagnostic ability, an ROC curve analysis was performed using our data, determining the optimal threshold for the test at 33.6 ng/mL of tear MMP-9. In addition, a confusion matrix was applied, estimating sensitivity at 60%, specificity at 88%, and accuracy at 68%. In conclusion, we demonstrated that the AbMAs system allows the quantification of MMP-9 in pathologies that involve inflammation of the ocular surface.     

Isocyanate-rich cellulose nanocrystals and their selective insertion in elastomeric polyurethane

Cellulose nanocrystals (CNC) were successfully obtained and modified with 1,6-hexamethylene diisocyanate (HDI) by means of in situ polymerization varying the CNC/HDI molar ratio to evaluate the number of anchored chains to the CNC. The modification was examined by elemental analysis, nuclear magnetic resonance (¹³C NMR) and attenuated total reflection Fourier transform infrared spectroscopy (IR-ATR). Nanocomposites containing 1.5 wt% CNC, modified and unmodified, were prepared by solvent casting. Thermal and mechanical properties of the resulting films were evaluated from the viewpoint of polyurethane microphase separated structure, soft and hard domains. CNC were effectively dispersed in the polyurethane matrix and depending on surface chemistry, the nanoreinforcement interacts selectively with matrix nanodomains. This interpretation is supported by differences in thermal and mechanical properties of the nanocomposites and also confirmed by AFM images. Isocyanate rich cellulose nanocrystals interacted with matrix hard phase, promoting physical association with hard segments, enhancing stiffness and dimensional stability versus temperature of the nanocomposite.     

Biodegradable composites with improved barrier properties and transparency from the impregnation of PLA to bacterial cellulose membranes

Poly(lactic acid) (PLA) was impregnated in bacterial cellulose (BC) membranes. BC/PLA films were prepared by solvent casting and mechanical, optical and barrier properties, and biodegradation process were investigated. The transparency of processed films was higher than that of neat BC and increased with PLA content. Moreover, the incorporation of PLA to BC enhanced significantly the water vapor barrier properties of the BC membranes. The bionanocomposites contained a high percentage of cellulose due to the impregnation method that leads to the film with a BC content of 94%, which practically maintains the excellent mechanical properties of BC. However, when increasing the PLA content in the bionanocomposites the mechanical properties decreased slightly with respect to BC. Biodegradation under real soil conditions was determined indirectly through the study of the visual degradation and disintegration, demonstrating that the bionanocomposites were degraded faster than the neat PLA. The successful production of BC/PLA bionanocomposites suggested the possible application of them for active food packaging. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43669.     

Thermal and fire behavior of isophorone diisocyanate based polyurethane foams containing conventional flame retardants

This work reports on the fire behavior of isophorone diisocyanate‐based polyurethane foams containing different conventional flame retardants (FRs) such as melamine, ammonium polyphosphate, aluminum hydroxide, expandable graphite, and their combinations. The foams were obtained in a laboratory scale and characterized in terms of their morphology, density, thermal stability, and fire behavior. According to atomic force microscopy, the incorporation of FRs decreased the phase separated domain size. The cellular structure of the foams was examined qualitatively by scanning electron microscopy while the quantitative analysis of the surrounding skin was performed by optical microscopy and Image J. The FR containing foams showed more and smaller cells. The thermogravimetric analysis showed that the FRs had no influence in the initial degradation temperature of the foams. However, the obtained residue values were higher than the theoretical ones, indicating that there was some type of interaction between the FRs and the foams. The fire behavior of polyurethane foams was studied by the cone calorimeter and the data showed that the introduction of expandable graphite and combinations of ammonium polyphosphate/melamine to the reference foam gave rise to a significant reduction in the total heat release. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45944.     

Microdomain composition and properties differences of biodegradable polyurethanes based on MDI and HDI

The study of the effect of the diisocyanate structure on the microstructure and macroscopic properties of polyurethanes was the main aim of this work. Biodegradable segmented thermoplastic elastomeric polyurethanes based on a poly(hexamethylene carbonate‐co‐caprolactone)diol (PHM‐co‐PCL) as soft segment were synthesized using 1,4‐butanediol (BD) as chain extender and both 4,4′‐diphenylmethane diisocyanate (MDI) and 1,6‐hexamethylene diisocyanate (HDI) as components of the hard segment by the two shoot synthesis procedure. Microphase structure and properties were analyzed using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) as complementary techniques, used to characterize thermal transitions of the polyurethanes and to assign them to determinate functional groups interactions. Gaussian deconvolution technique was used to decompose carbonyl region in four peaks and to study the hydrogen bonding within the different polyurethanes. Both DSC and FTIR showed that MDI‐based biodegradable polyurethanes were less phase segregated than to those based on HDI, and thus that diisocyanate structure has an important role on microdomain composition and polyurethanes properties. Macroscopic properties as hardness and water‐polymer contact angles are related to polyurethanes microphase compositions. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.     

The Role of Circulating Biomarkers in Peripheral Arterial Disease

Peripheral arterial disease (PAD) of the lower extremities is a chronic illness predominantly of atherosclerotic aetiology, associated to traditional cardiovascular (CV) risk factors. It is one of the most prevalent CV conditions worldwide in subjects >65 years, estimated to increase greatly with the aging of the population, becoming a severe socioeconomic problem in the future. The narrowing and thrombotic occlusion of the lower limb arteries impairs the walking function as the disease progresses, increasing the risk of CV events (myocardial infarction and stroke), amputation and death. Despite its poor prognosis, PAD patients are scarcely identified until the disease is advanced, highlighting the need for reliable biomarkers for PAD patient stratification, that might also contribute to define more personalized medical treatments. In this review, we will discuss the usefulness of inflammatory molecules, matrix metalloproteinases (MMPs), and cardiac damage markers, as well as novel components of the liquid biopsy, extracellular vesicles (EVs), and non-coding RNAs for lower limb PAD identification, stratification, and outcome assessment. We will also explore the potential of machine learning methods to build prediction models to refine PAD assessment. In this line, the usefulness of multimarker approaches to evaluate this complex multifactorial disease will be also discussed.     

Local Preirradiation of Infarcted Cardiac Tissue Substantially Enhances Cell Engraftment

The success of cell therapy for the treatment of myocardial infarction depends on finding novel approaches that can substantially implement the engraftment of the transplanted cells. In order to enhance cell engraftment, most studies have focused on the pretreatment of transplantable cells. Here we have considered an alternative approach that involves the preconditioning of infarcted heart tissue to reduce endogenous cell activity and thus provide an advantage to our exogenous cells. This treatment is routinely used in other tissues such as bone marrow and skeletal muscle to improve cell engraftment, but it has never been taken in cardiac tissue. To avoid long-term cardiotoxicity induced by full heart irradiation we developed a rat model of a catheter-based heart irradiation system to locally impact a delimited region of the infarcted cardiac tissue. As proof of concept, we transferred ZsGreen⁺ iPSCs in the infarcted heart, due to their ease of use and detection. We found a very significant increase in cell engraftment in preirradiated rats. In this study, we demonstrate for the first time that preconditioning the infarcted cardiac tissue with local irradiation can substantially enhance cell engraftment.     

Raman analysis of surimi gelation by addition of wheat dietary fibre

Raman analysis has been carried out to study the effects of Vitacel^® wheat dietary fibre (WDF) during gelation of surimi. The main results reveal the following: (a) Vitacel^® comprises natural cellulose I as major component; (b) hydration of WDF leads to νCH frequency upshifting and decreasing intensity. On the basis of these spectral features it is suggested that water transfer from protein to WDF can occur in surimi gels. WDF hydration can be interpreted in the sense that this fibre either takes water that is delivered from the gel protein upon heat-mediated formation of β-sheets and hydrophobic contacts and/or or acts as an active dehydrating agent. An increase of solvent-exposed hydrophobic side chains is observed in the sol phase, upon the addition of WDF, which may cause breaking of intermolecular protein hydrophobic contacts; a subsequent change upon WDF-containing gel formation is the reduction in the νCH intensity, which may be indicative of increasing hydrophobic WDF-protein contacts. Interestingly, these results constitute molecular data, to be considered when designing restructured fish products with these fibre ingredients.