Interference of Dermatophagoides pteronyssinus sensitization in grass pollen allergy.

Summary: Background. Climate conditions in the northwest of Spain are from the rest of the country, and the pollen sensitisation rates and allergens involved are different. The present study aimed to investigate the sensitisation profile of patients with grass pollen allergy and the interference of other sensitisations in respiratory symptoms. Methods. A total of 959 Spanish patients with seasonal respiratory symptoms and a positive skin prick test (SPT) to Phleum pratense pollen were studied. Patients were classified as having rhinitis and/or bronchial asthma. A battery of SPTs, including common weeds and tree pollens, profilin, polcalcin, moulds, Dermatophagoides pteronyssinus, Lepidoglyphus destructor, and cat and dog dander were performed. Serum specific IgE (sIgE) to Phl p 1 and Phl p 5, adding sIgE to Phl p 7, Phl p 12 and house dust mites (HDMs) or other pollens in selected cases were measured. Results.The majority (89.8%) of the patients were polysensitised according to SPT. HDM co-sensitisation was the most prevalent (62.3%). Profilin and polcalcin rendered a positive result in 25.9% and 18.7% of the patients, respectively. A higher proportion of patients recognized sIgE to Phl p 1 (88.7%) with respect to Phl p 5 (59%). Phl p 1-sIgE levels were higher than Phl p 5-sIgE levels, and no differences were found in patients with rhinitis and/or asthma. However, total serum IgE was higher in patients with asthma. Multivariate regression analyses revealed that only sIgE to Dermatophagoides pteronyssinus (after adjusting by sIgE to Phl p 1, Phl p 5 and Lepidoglyphus destructor) was associated with a greater risk of asthma. Conclusions. Phl p 1 is the most relevant allergen in patients with grass pollen allergy in the northwest of Spain. Sensitisation rates against panallergens are low. Even in patients with grass pollen allergy, HDM sensitisation plays a relevant role in asthma.

Osteogenic preconditioning in perfusion bioreactors improves vascularization and bone formation by human bone marrow aspirates.

Cell-derived extracellular matrix (ECM) provides a niche to promote osteogenic differentiation, cell adhesion, survival, and trophic factor secretion. To determine whether osteogenic preconditioning would improve the bone-forming potential of unfractionated bone marrow aspirate (BMA), we perfused cells on ECM-coated scaffolds to generate naïve and preconditioned constructs, respectively. The composition of cells selected from BMA was distinct on each scaffold. Naïve constructs exhibited robust proangiogenic potential in vitro, while preconditioned scaffolds contained more mesenchymal stem/stromal cells (MSCs) and endothelial cells (ECs) and exhibited an osteogenic phenotype. Upon implantation into an orthotopic calvarial defect, BMA-derived ECs were present in vessels in preconditioned implants, resulting in robust perfusion and greater vessel density over the first 14 days compared to naïve implants. After 10 weeks, human ECs and differentiated MSCs were detected in de novo tissues derived from naïve and preconditioned scaffolds. These results demonstrate that bioreactor-based preconditioning augments the bone-forming potential of BMA.

Pore-forming bioinks to enable spatio-temporally defined gene delivery in bioprinted tissues.

The regeneration of complex tissues and organs remains a major clinical challenge. With a view towards bioprinting such tissues, we developed a new class of pore-forming bioink to spatially and temporally control the presentation of therapeutic genes within bioprinted tissues. By blending sacrificial and stable hydrogels, we were able to produce bioinks whose porosity increased with time following printing. When combined with amphipathic peptide-based plasmid DNA delivery, these bioinks supported enhanced non-viral gene transfer to stem cells in vitro. By modulating the porosity of these bioinks, it was possible to direct either rapid and transient (pore-forming bioinks), or slower and more sustained (solid bioinks) transfection of host or transplanted cells in vivo. To demonstrate the utility of these bioinks for the bioprinting of spatially complex tissues, they were next used to zonally position stem cells and plasmids encoding for either osteogenic (BMP2) or chondrogenic (combination of TGF-ß3, BMP2 and SOX9) genes within networks of 3D printed thermoplastic fibers to produce mechanically reinforced, gene activated constructs. In vivo, these bioprinted tissues supported the development of a vascularised, bony tissue overlaid by a layer of stable cartilage. When combined with multiple-tool biofabrication strategies, these gene activated bioinks can enable the bioprinting of a wide range of spatially complex tissues.

Mesenchymal stem cell fate following non-viral gene transfection strongly depends on the choice of delivery vector.

Controlling the phenotype of mesenchymal stem cells (MSCs) through the delivery of regulatory genes is a promising strategy in tissue engineering (TE). Essential to effective gene delivery is the choice of gene carrier. Non-viral delivery vectors have been extensively used in TE, however their intrinsic effects on MSC differentiation remain poorly understood. The objective of this study was to investigate the influence of three different classes of non-viral gene delivery vectors: (1) cationic polymers (polyethylenimine, PEI), (2) inorganic nanoparticles (nanohydroxyapatite, nHA) and (3) amphipathic peptides (RALA peptide) on modulating stem cell fate after reporter and therapeutic gene delivery. Despite facilitating similar reporter gene transfection efficiencies, these nanoparticle-based vectors had dramatically different effects on MSC viability, cytoskeletal morphology and differentiation. After reporter gene delivery (pGFP or pLUC), the nHA and RALA vectors supported an elongated MSC morphology, actin stress fibre formation and the development of mature focal adhesions, while cells appeared rounded and less tense following PEI transfection. These changes in MSC morphology correlated with enhanced osteogenesis following nHA and RALA transfection and adipogenesis following PEI transfection. When therapeutic genes encoding for transforming growth factor beta 3 (TGF-ß3) and/or bone morphogenic protein 2 (BMP2) were delivered to MSCs, nHA promoted osteogenesis in 2D culture and the development of an endochondral phenotype in 3D culture, while RALA was less osteogenic and appeared to promote a more stable hyaline cartilage-like phenotype. In contrast, PEI failed to induce robust osteogenesis or chondrogenesis of MSCs, despite effective therapeutic protein production. Taken together, these results demonstrate that the differentiation of MSCs through the application of non-viral gene delivery strategies depends not only on the gene delivered, but also on the gene carrier itself. STATEMENT OF SIGNIFICANCE: Nanoparticle-based non-viral gene delivery vectors have been extensively used in regenerative medicine, however their intrinsic effects on mesenchymal stem cell (MSC) differentiation remain poorly understood. This paper demonstrates that different classes of commonly used non-viral vectors are not inert and they have a strong effect on cell morphology, stress fiber formation and gene transcription in MSCs, which in turn modulates their capacity to differentiate towards osteogenic, adipogenic and chondrogenic lineages. These results also point to the need for careful and tissue-specific selection of nanoparticle-based delivery vectors to prevent undesired phenotypic changes and off-target effects when delivering therapeutic genes to damaged or diseased tissues.

Herpes-like eruption due to Fluconazole

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