Nanoparticles for the regulation of intestinal inflammation: opportunities and challenges.

Prevalence of chronic inflammation of the gastrointestinal tract is increasing, emerging as a public health challenge. Conventional drug delivery systems targeting the colon have improved the treatment of inflammatory bowel disease. However, therapy frequently results in inconsistent efficacy and toxicity problems. Novel approaches based on nanoparticles offer several advantages over conventional dosage forms due to their ability to selectively target inflamed tissues. Several formulation efforts have been made in order to obtain increasingly selective nanosized systems, some with promising results in animal models of colitis. Despite all advances, no nanomedicines are yet approved for clinical use in inflammatory bowel disease. This review discusses the most recent efforts made toward the development of nanoparticles for regulating chronic intestinal inflammation.

Publisher Correction: On the issue of transparency and reproducibility in nanomedicine.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Development and validation of a new one step Multiplex-PCR assay for the detection of ten Lactobacillus species.

Lactobacillus sp. are well-known colonizers of human mucosa and frequently used as probiotics. Accurate species identification is crucial both for fundamental studies and biotechnology applications; however, it has been thus far challenging. The aim of this work was to develop a one-step multiplex-PCR assay for detection of ten Lactobacillus species (L. jensenii, L. fermentum, L. acidophilus, L. crispatus, L. reuteri, L. iners, L. casei, L. gasseri, L. plantarum, L. rhamnosus) directly in complex bacterial genomic DNA. A multiplex-PCR assay was optimized based on Box-Behnken experimental design, which showed to be efficient for optimization of all crucial reaction components. Nineteen Lactobacillus strains, including six collection strains and thirteen human isolates were used in order to verify the specificity and sensitivity of the assay. In addition, a set of PCR adjuvants was introduced to remove non-specific amplifications and enhance reaction yield. Among them, Triton™ X-100, Tween® 20, BSA, and dithiothreitol showed beneficial effects when compared with other adjuvants. The application of the developed method to samples that resulted from the mixing of DNA from the ten strains, resulted in amplicons of the expected sizes (from about 100 to 1000 bp). The detection limit was 1.25 ng/µl for all species with the exception of L. gasseri (0.31 ng/µl). In order to confirm the method applicability on human samples, ten vaginal fluids were enrolled in this study showing that the method can be successfully used on these biological materials. The proposed multiplex-PCR assay was shown to be selective, sensitive and efficient for detection of ten Lactobacillus species directly in human vaginal samples. This method provides a cost-effective and accessible methodology applicable to the detection of Lactobacillus species to different environments. At the same time, this approach represents a considerable improvement over other PCR-based approaches for identification of these species.

Electrospun fibrous membranes featuring sustained release of ibuprofen reduce adhesion and improve neurological function following lumbar laminectomy.

Electrospun fibrous membranes provide suitable physical anti-adhesion barriers for reducing tissue anti-adhesion following surgery. However, often during the biodegradation process, these barriers trigger inflammation and cause a foreign body reaction with subsequent decrease in anti-adhesion efficacy. Here, a facile strategy comprising the incorporation of ibuprofen (IBU) into implantable membranes and its sustained release was proposed in order to improve anti-adhesion effects and neurological outcomes, namely to prevent failed back surgery syndrome (FBSS). The combination of free IBU and a newly synthetized polymeric prodrug of IBU, namely poly(hydroxyethyl methacrylate) with ester-linked IBU, was successfully used in order to reduce initial burst drug release and provide sustained drug release from fibrous membranes throughout several weeks. Such release profile was shown useful in preventing both acute and chronic inflammation in rats following laminectomy and membrane implantation. Moreover, histological analysis provided evidence of an excellent anti-adhesion effect, while associated neurological deficits were effectively reduced. Furthermore, the assessment of macrophage density, neovascularization, and related gene expression at the lesion site revealed that a sustained anti-inflammatory effect was achieved with the IBU-loaded proposed fibrous membranes. Results suggested that the COX2 pathway plays an important role in the development epidural fibrosis and arachnoiditis. Overall, this study provided evidence that precisely engineered IBU-loaded electrospun fibrous membranes may be useful in preventing FBSS and able to potentially impact the outcome of patients undergoing spine surgery.

Co-association of methotrexate and SPIONs into anti-CD64 antibody-conjugated PLGA nanoparticles for theranostic application.

BACKGROUND: Rheumatoid arthritis (RA) is an autoimmune disease with severe consequences for the quality of life of sufferers. Regrettably, the inflammatory process involved remains unclear, and finding successful therapies as well as new means for its early diagnosis have proved to be daunting tasks. As macrophages are strongly associated with RA inflammation, effective diagnosis and therapy may encompass the ability to target these cells. In this work, a new approach for targeted therapy and imaging of RA was developed based on the use of multifunctional polymeric nanoparticles. METHODS: Poly(lactic-co-glycolic acid) nanoparticles were prepared using a single emulsion-evaporation method and comprisaed the co-association of superparamagnetic iron oxide nanoparticles (SPIONs) and methotrexate. The nanoparticles were further functionalized with an antibody against the macrophage-specific receptor, CD64, which is overexpressed at sites of RA. The devised nanoparticles were characterized for mean particle size, polydispersity index, zeta potential, and morphology, as well as the association of SPIONs, methotrexate, and the anti-CD64 antibody. Lastly, the cytotoxicity of the developed nanoparticles was assessed in RAW 264.7 cells using standard MTT and LDH assays. RESULTS: The nanoparticles had a mean diameter in the range of 130-200 nm and zeta potential values ranging from -32 mV to -16 mV. Association with either methotrexate or SPIONs did not significantly affect the properties of the nanoparticles. Conjugation with the anti-CD64 antibody, in turn, caused a slight increase in size and surface charge. Transmission electron microscopy confirmed the association of SPIONs within the poly(lactic-co-glycolic acid) matrix. Both anti-CD64 and methotrexate association were confirmed by Fourier transform infrared spectroscopy, and quantified yielding values as high as 36% and 79%, respectively. In vitro toxicity studies confirmed the methotrexate-loaded nanosystem to be more effective than the free drug. CONCLUSION: Multifunctional anti-CD64-conjugated poly(lactic-co-glycolic acid) nanoparticles for the combined delivery of methotrexate and SPIONs were successfully prepared and characterized. This nanosystem has the potential to provide a new theranostic approach for the management of RA.

Nanoparticle-based drug delivery to improve the efficacy of antiretroviral therapy in the central nervous system.

Antiretroviral drug therapy plays a cornerstone role in the treatment of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome patients. Despite obvious advances over the past 3 decades, new approaches toward improved management of infected individuals are still required. Drug distribution to the central nervous system (CNS) is required in order to limit and control viral infection, but the presence of natural barrier structures, in particular the blood-brain barrier, strongly limits the perfusion of anti-HIV compounds into this anatomical site. Nanotechnology-based approaches may help providing solutions for antiretroviral drug delivery to the CNS by potentially prolonging systemic drug circulation, increasing the crossing and reducing the efflux of active compounds at the blood-brain barrier, and providing cell/tissue-targeting and intracellular drug delivery. After an initial overview on the basic features of HIV infection of the CNS and barriers to active compound delivery to this anatomical site, this review focuses on recent strategies based on antiretroviral drug-loaded solid nanoparticles and drug nanosuspensions for the potential management of HIV infection of the CNS.

Chitosan-coated solid lipid nanoparticles for insulin delivery.

The delivery of therapeutic proteins like insulin, exploiting routes of administration different from the traditional injectable forms, has been investigated extensively, taking advantage of the nanotechnology tools available nowadays in the massive drug delivery system pipeline. In this chapter, we describe in detail the preparation of solid lipid nanoparticles (SLN), further coated with the mucoadhesive polymer chitosan, intended for intestinal absorption of insulin after oral administration. We give special focus on the characterization of the SLN and of the biomacromolecule by itself after encapsulation, because of the intrinsic labile properties of insulin during the manufacturing process. We also describe methods to determine the in vitro intestinal permeability of insulin that solid lipid and chitosan-coated SLN can afford, as well as in vivo models to evaluate the hypoglycemic effect in diabetic animals.