Lipid nanoparticles as delivery vehicles for the Parietaria judaica major allergen Par j 2

Nanoparticles in allergen immunotherapy

PURPOSE OF REVIEW

Allergen immunotherapy is the only recognized causal treatment for allergic disease that modulates the immune system toward a tolerogenic or desensitized state. Allergens or their derivative preparations are formulated with adjuvants of different origin and having diverse immunological functions, such as prolonged tissue release and specific immunomodulatory properties. In the last 2 decades, thanks to developments in the field of nanotechnology, more biosafe nanoscale materials have become available for use as pharmaceutical adjuvants in medical research.

RECENT FINDINGS

Nanomaterials possess unique and versatile properties which can be employed to develop drug carriers with safer profiles, better stability in physiological conditions and immunomodulatory properties. Nanoparticles can have an adjuvant effect per se or also when they are packed in structures whose physical-chemical properties can be handled in a way that also influences its release dynamics. In particular, it has been suggested that nanoparticle preparations can be put in complexes or loaded with allergens or allergenic extracts, opening the way to innovative paradigms.

SUMMARY

In this review, we analyze allergen/nanoparticle properties in terms of cytotoxicity, stability and immunogenic reaction in in-vitro and animal systems.

Formulations for Allergen Immunotherapy in Human and Veterinary Patients: New Candidates on the Horizon

Allergen immunotherapy is currently the only causal treatment for allergic diseases in human beings and animals. It aims to re-direct the immune system into a tolerogenic or desensitized state. Requirements include clinical efficacy, safety, and schedules optimizing patient or owner compliance. To achieve these goals, specific allergens can be formulated with adjuvants that prolong tissue deposition and support uptake by antigen presenting cells, and/or provide a beneficial immunomodulatory action. Here, we depict adjuvant formulations being investigated for human and veterinary allergen immunotherapy.

Parietaria Allergy: An Intriguing Challenge for the Allergist

Parietaria pollen is the most important cause of pollen allergies in the Mediterranean area, as Parietaria is widespread in this region. Many issues are associated with Parietaria allergy, including the duration of the pollen season (many doctors in fact believe that it lasts throughout the year), pollen load (which seems to be increasing over time), the impact of age (on IgE production and symptom severity), inflammatory changes (after pollen exposure), and the choice of allergen immunotherapy (AIT). In addition, molecular diagnostics allows for the defining of a correct diagnosis, differentiating between mere sensitization and true allergy. This review considers these topics and will hopefully help the allergist in clinical practice. Parietaria allergy is an intriguing challenge for the allergist in clinical practice, but it may be adequately managed by knowing the peculiarities of respective territories and the clinical characteristics of each patient.

Nanoparticle-allergen complexes for allergen immunotherapy

Allergen-specific immunotherapy was introduced in clinical settings more than 100 years ago. It remains the only curative approach to treating allergic disorders that ameliorates symptoms, reduces medication costs, and blocks the onset of new sensitizations. Despite this clinical evidence and knowledge of some immunological mechanisms, there remain some open questions regarding the safety and efficacy of this treatment. This suggests the need for novel therapeutic approaches that attempt to reduce the dose and frequency of treatment administration, improving patient compliance, and reducing costs. In this context, the use of novel adjuvants has been proposed and, in recent years, biomedical applications using nanoparticles have been exploited in the attempt to find formulations with improved stability, bioavailability, favorable biodistribution profiles, and the capability of targeting specific cell populations. In this article, we review some of the most relevant regulatory aspects and challenges concerning nanoparticle-based formulations with immunomodulatory potential, their related immunosafety issues, and the nature of the nanoparticles most widely employed in the allergy field. Furthermore, we report in vitro and in vivo data published using allergen/nanoparticle systems, discuss their impact on the immune system in terms of immunomodulatory activity and the reduction of side effects, and show that this strategy is a novel and promising tool for the development of allergy vaccines.

Effects in cigarette smoke stimulated bronchial epithelial cells of a corticosteroid entrapped into nanostructured lipid carriers

BACKGROUND

Nanomedicine studies have showed a great potential for drug delivery into the lung. In this manuscript nanostructured lipid carriers (NLC) containing Fluticasone propionate (FP) were prepared and their biocompatibility and effects in a human bronchial epithelial cell line (16-HBE) stimulated with cigarette smoke extracts (CSE) were tested.

RESULTS

Biocompatibility studies showed that the NLC did not induce cell necrosis or apoptosis. Moreover, it was confirmed that CSE increased intracellular ROS production and TLR4 expression in bronchial epithelial cells and that FP-loaded NLC were more effective than free drug in modulating these processes. Finally, the nanoparticles increased GSH levels improving cell protection against oxidative stress.

CONCLUSIONS

The present study shows that NLC may be considered a promising strategy to improve corticosteroid mediated effects in cellular models associated to corticosteroid resistance. The NLC containing FP can be considered good systems for dosage forms useful for increasing the effectiveness of fluticasone decreasing its side effects.