Spray-dried fucoidan microparticles for pulmonary delivery of antitubercular drugs

Pulmonary tuberculosis accounts for 80% of cases and the delivery of antitubercular drugs into the lungs allows targeting the infected organ and, possibly, reducing systemic drug toxicity. This work aimed at using fucoidan as matrix of inhalable microparticles that associate two first-line antitubercular drugs, for an application in pulmonary tuberculosis therapy. Fucoidan is composed of fucose and sulphated sugar residues, moieties described as being recognised by surface receptors of alveolar macrophages, which host mycobacteria. Inhalable fucoidan microparticles loaded with antitubercular drugs were successfully produced with high association efficiencies of either isoniazid (95%) or rifabutin (81%). The microparticles evidenced no cytotoxicity on lung epithelial cells (A549). However, rifabutin-loaded microparticles showed a certain degree of toxicity on macrophage-like cells (THP-1) at the highest tested concentration (1?mg/mL). Furthermore, microparticles showed favourable aerodynamic properties for deep lung delivery (MMAD 2.0–3.8?µm) and, thus, show potential for an application as inhalable tuberculosis therapy.     

Engineering strategies to control vascular endothelial growth factor stability and levels in a collagen matrix for angiogenesis: The role of heparin sodium salt and the PLGA-based microsphere approach

New vessel formation is the result of the complex orchestration of various elements, such as cells, signalling molecules and extracellular matrix (ECM). In order to establish the suitable conditions for an effective cell response, the influence of vascular endothelial growth factor (VEGF) complexation with heparin sodium salt (Hp) on its pro-angiogenic activity has been evaluated by an in vitro capillary-like tube formation assay. VEGF with or without Hp was embedded into collagen gels, and the activated matrices were characterized in terms of VEGF activity and release kinetics. Taking into account the crucial role of Hp in VEGF stability and activity, VEGF/Hp complex was then encapsulated into microspheres based on poly(lactide-co-glycolide) (PLGA), and microsphere properties, VEGF/Hp release kinetics and VEGF in vitro activity over time were evaluated. Integrated microsphere/collagen matrices were developed in order to provide a continuous release of active VEGF/Hp inside the matrix but also a VEGF gradient at the boundary, which is an essential condition for endothelial cell attraction and scaffold invasion. The results confirmed a strong influence of Hp on VEGF configuration and, consequently, on its activity, while the encapsulation of VEGF/Hp complex in PLGA-microspheres guaranteed a sustained release of active VEGF for more than 30 days. This paper confirms the importance of VEGF stability and signal presentation to cells for an effective proangiogenic activity and highlights how the combination of two stabilizing approaches, namely VEGF/Hp complexation and entrapment within PLGA-based microspheres, may be a very effective strategy to achieve this goal.     

Prospective technical validation and assessment of intra-tumour heterogeneity of a low density array hypoxia gene profile in head and neck squamous cell carcinoma

Background and purposeTumour hypoxia is associated with a poor prognosis in head and neck squamous cell carcinoma (HNSCC), however there is no accepted method for assessing hypoxia clinically. We aimed to conduct a technical validation of a hypoxia gene expression signature using the TaqMan Low Density Array (TLDA) platform to investigate if this approach reliably identified hypoxic tumours.Materials and methodsTumour samples (n = 201) from 80 HNSCC patients were collected prospectively from two centres. Fifty-three patients received pimonidazole prior to surgery. TaqMan Low Density Array-Hypoxia Scores (TLDA-HS) were obtained by quantitative real-time PCR (qPCR) using a 25-gene signature and customised TLDA cards. Assay performance was assessed as coefficient of variation (CoV).ResultsThe assay was sensitive with linear reaction efficiencies across a 4log₁₀ range of inputted cDNA (0.001–10 ng/μl). Intra- (CoV = 6.9%) and inter- (CoV = 2.0%) assay reproducibility were excellent. Intra-tumour heterogeneity was lower for TLDA-HS (23.2%) than for pimonidazole (67.2%) or single gene measurements of CA9 (62.2%), VEGFA (45.0%) or HIG2 (39.4%). TLDA-HS in HNSCC cell lines increased with decreasing pO₂. TLDA-HS correlated with Affymetrix U133 Plus 2.0 microarray HS (p < 0.01) and positive pimonidazole scores (p = 0.005).ConclusionsGene expression measurements of hypoxia using a 25-gene signature and TLDA cards are sensitive, reproducible and associated with lower intra-tumour heterogeneity than assaying individual genes or pimonidazole binding. The approach is suitable for further assessment of prognostic and predictive capability in clinical trial material.     

Which advises for primary food allergy prevention in normal or high‐risk infant?

In the last decades, international guidelines proposed different strategies of complementary foods introduction during weaning to prevent allergy. Avoidance measures, such as late introduction of allergenic foods, failed to show a significant preventive effect towards allergy. Recently, prospective randomized controlled studies suggested that the early introduction of solid foods ‐ rather than the late introduction ‐ could be a strategy to prevent allergic sensitization and food allergy. However, at today clear evidence of effectiveness and safety of early introduction are not yet available to recommend a radical change in the current clinical practice. A realistic advice for the general population could be to begin the weaning at 4–5 months with the progressive introduction of different foods. The advices for introduction of solid foods during weaning should also take in consideration the global development of child to chose the better timing of introduction of foods.