Anxiety and depression risk in patients with allergic rhinitis: a systematic review and meta-analysis.

BACKGROUND: Allergic diseases appear to be associated with mood disorders. However, particularly regarding allergic rhinitis (AR), such association has not been adequately systematically reviewed. Therefore, we conducted a systematic review and meta-analysis to quantify the association between AR and depression and anxiety. METHODOLOGY: We performed an electronic search of PubMed, Web of Science and Scopus for observational studies assessing the association between AR and depression and anxiety. Such association was quantified by means of random-effects meta-analysis, with estimation of pooled odds ratio (OR). Sources of heterogeneity were explored by subgroup analysis. RESULTS: We included a total of 24 primary studies, of which 23 assessed depression and 11 assessed anxiety. Of these, 12 studies presented OR from multivariable regression models and were included in our meta-analysis. AR was associated with higher odds of depression and anxiety. CONCLUSIONS: AR appears to be associated with high risk of depression and anxiety. While our results point to the importance of mental comorbidities among patients with AR, longitudinal studies are needed adopting uniform definitions and presenting results stratified by AR severity.

Challenges and strategies for the delivery of biologics to the cornea.

Biologics, like peptides, proteins and nucleic acids, have proven to be promising drugs for the treatment of numerous diseases. However, besides the off label use of the monoclonal antibody bevacizumab for the treatment of corneal neovascularization, to date no other biologics for corneal diseases have reached the market. Indeed, delivering biologics in the eye remains a challenge, especially at the level of the cornea. While it appears to be a rather accessible tissue for the administration of drugs, the cornea in fact presents several anatomical barriers to delivery. In addition, also intracellular delivery barriers need to be overcome to achieve a promising therapeutic outcome with biologics. This review outlines efforts that have been reported to successfully deliver biologics into the cornea. Biochemical and physical methods for achieving delivery of biologics in the cornea are discussed, with a critical view on their efficacy in overcoming corneal barriers.

Autocrine CCL2, CXCL4, CXCL9 and CXCL10 signal in retinal endothelial cells and are enhanced in diabetic retinopathy.

This study aimed at examining the presence and role of chemokines (angiogenic CCL2/MCP-1 and angiostatic CXCL4/PF-4, CXCL9/Mig, CXCL10/IP-10) in proliferative diabetic retinopathy (PDR). Regulated chemokine production in human retinal microvascular cells (HRMEC) and chemokine levels in vitreous samples from 40 PDR and 29 non-diabetic patients were analyzed. MCP-1, PF-4, Mig, IP-10 and VEGF levels in vitreous fluid from PDR patients were significantly higher than in controls. Except for IP-10, cytokine levels were significantly higher in PDR with active neovascularization and PDR without traction retinal detachment (TRD) than those in inactive PDR, PDR with TRD and control subjects. Exploratory regression analysis identified associations between higher levels of IP-10 and inactive PDR and PDR with TRD. VEGF levels correlated positively with MCP-1 and IP-10. Significant positive correlations were observed between MCP-1 and IP-10 levels. In line with these clinical findings Western blot analysis revealed increased PF-4 expression in diabetic rat retinas. HRMEC produced MCP-1, Mig and IP-10 after stimulation with IFN-γ, IL-1ß or lipopolysaccharide. IFN-γ synergistically enhanced Mig and IP-10 production in response to IL-1ß or lipopolysaccharide. MCP-1 was produced by HRMEC in response to VEGF treatment and activated HRMEC via the ERK and Akt/PKB pathway. On the other hand, phosphorylation of ERK induced by VEGF and MCP-1 was inhibited by PF-4, Mig and IP-10. In accordance with inhibition of angiogenic signal transduction pathways, PF-4 inhibited in vitro migration of HRMEC. Thus, regulatory roles for chemokines in PDR were demonstrated. In particular, IP-10 might be associated with the resolution of active PDR and the development of TRD.

Matrix systems for siRNA delivery.

Over the last decade, considerable effort has been put in the implementation of RNA interference (RNAi) as a treatment for various disorders. As RNAi occurs in the cytoplasm of cells, it is imperative that RNAi mediators such as small interfering RNA (siRNA) cross several extracellular and intracellular barriers to reach this site of action. Among the extensive range of proposed delivery systems for siRNA, matrix systems possess interesting properties to promote the delivery of siRNA to a target tissue. In this review, a number of recently developed matrix and hybrid systems for siRNA delivery are discussed.

PEGylation of biodegradable dextran nanogels for siRNA delivery.

Delivering intact small interfering RNA (siRNA) into the cytoplasm of targeted cells in vivo is considered a major obstacle in the development of clinically applicable RNA interference-based therapies. Although dextran hydroxyethyl methacrylate (dex-HEMA) nanogels have been reported to be suitable carriers for siRNA delivery in vitro, and are ideally sized (approximately 180 nm) for intravenous delivery to tumors, they likely possess insufficient blood circulation times to enable an adequate extravasation and accumulation in the tumor tissue. PEGylation of these nanogels should not only improve their circulation time but also minimize their aggregation upon intravenous injection. For this reason, a new type of nanogels and three different methods of PEGylating dextran nanogels were evaluated. Covalent PEGylation of the siRNA-loaded nanogels using N-hydroxysuccinimidyl polyethylene glycol (NHS-PEG) was shown to be superior to the addition of both polyethylene glycol (PEG) and PEG grafted poly-l-glutamic acid (PGA-PEG). Flow cytometry and confocal microscopy revealed that PEGylated nanogels are still taken up efficiently by HuH-7 human hepatoma cells and A431 human epithelial carcinoma cells and that the process is cell type dependent. Moreover, PEGylated nanogels loaded with siRNA cause significant EGFP knockdown in a human hepatoma cell line (HuH-7_EGFP) and are non-toxic for these cells.

Prolonged gene silencing by combining siRNA nanogels and photochemical internalization.

Small interfering RNAs (siRNAs) show potential for the treatment of a wide variety of pathologies with a known genetic origin through sequence-specific gene silencing. However, siRNAs do not have favorable drug-like properties and need to be packaged into nanoscopic carriers that are designed to guide the siRNA to the cytoplasm of the target cell. In this report biodegradable cationic dextran nanogels are used to deliver siRNA across the intracellular barriers. For the majority of non-viral siRNA carriers studied so far, endosomal confinement is identified as the most prominent hurdle, limiting the full gene silencing potential. Thus, there is a major interest in methods that are able to enhance endosomal escape of siRNA to improve its intracellular bioavailability. Photochemical internalization (PCI) is a method that employs amphiphilic photosensitizers to destabilize endosomal vesicles. We show that applying PCI at a later time-point post-transfection significantly prolonged the knockdown of the target protein only in case the siRNA was carried by nanogels and not when a liposomal carrier was used. Combining siRNA nanogels and PCI creates new possibilities to prolong gene silencing by using intracellular vesicles as depots for siRNA and applying PCI at the time when maintaining the RNAi effect becomes critical.

House dust mite induces direct airway inflammation in vivo: implications for future disease therapy?

House dust mite (HDM) is the major source of allergen in house dust and is strongly associated with the development of asthma. HDM can evoke a direct, nonallergic inflammatory reaction in vitro. We aimed to determine whether this apparent nonallergic, inflammatory response can be observed in a more complex in vivo setting. Vehicle, Alum or HDM (Dermatophagoides pteronyssinus 5 microg, i.p. with Alum) sensitised Brown-Norway rats were challenged intratracheally with vehicle (saline), HDM (Der p 10 microg) or heat-inactivated HDM on day 21. Lung function changes and the associated inflammatory response were evaluated. Tissue and bronchoalveolar lavage from Alum sensitised Der p challenged animals exhibited strong eosinophilia and neutrophilia associated with an early release of pro-inflammatory cytokines (interleukin-13 and 1beta, eotaxin and thymus and activation-regulated chemokine). This response was not attenuated by removal of HDM-associated protease activity. Interestingly, the vehicle sensitised group (no Alum) lacked this inflammatory response. HDM allergen evokes nonallergic airways inflammation with an inflammatory profile similar to that of the asthmatic airway. This response, independent of the protease activity of the HDM extract, appeared to be linked to prior administration of the adjuvant Alum and the subsequent increase in total immunoglobulin E. This finding could have important implications in the development of future asthma therapies.

Protein release from biodegradable dextran nanogels.

The use of drugs with intracellular targets will strongly depend on the availability of delivery systems that are able to deliver them to specific intracellular sites at an optimal rate. Biodegradable dextran nanogels were prepared using liposomes as a nanoscaled reactor.1,2 These nanogels were obtained by UV polymerization of dextran hydroxyethylmethacrylate (dex-HEMA) containing 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) liposomes. We found the encapsulation efficiency of bovine serum albumin (BSA) and lysozyme in the dextran nanogels to be about 50%. Specifically, the release of BSA and lysozyme from the dextran nanogels was clearly governed by the cross-link density of the tiny gels. Depending on the size of the encapsulated protein, the cross-link density of the dextran network, and the presence or absence of a lipid coating, proteins were released from the nanogels over days to weeks. Interestingly, when sufficiently diluted, dextran nanogels did not aggregate in human serum, which is of major importance when one considers intravenous administration of such nanogels. Also, reconstitution of lyophilized dextran nanogels seemed perfectly possible, which is also an important finding since dextran nanogels will have to be stored in dry form. Because dextran nanogels can be taken up by cells, they are promising materials for controlled intracellular release of proteins.

Can we better understand the intracellular behavior of DNA nanoparticles by fluorescence correlation spectroscopy?

The use of non-viral gene carriers to deliver small nucleic acids like antisense oligonucleotides (ODNs) and small interfering RNA (siRNA) remains an attractive but challenging goal in antisense therapy. Indeed, different barriers need to be overcome in the delivery process before a therapeutic effect can be obtained. One promising technique which we have been evaluating to improve our understanding of the intracellular behavior of nucleic acids/carrier complexes is Fluorescence Correlation Spectroscopy (FCS). In particular, we have used FCS for studying the protection of the nucleic acids against enzymatic degradation, and the association and dissociation of the nucleic acids with their carrier, both in buffer and in living cells. In this report, we will review our experience and findings on the use of FCS for that purpose and discuss the strengths and weaknesses of this interesting technique.

Protection of oligonucleotides against enzymatic degradation by pegylated and nonpegylated branched polyethyleneimine.

Among the cationic polymers, polyethyleneimine (PEI) is a promising candidate for delivery of oligodeoxynucleotides (ODNs). In this study, we wondered whether pegylation of PEI influences the complexation with ODNs. We especially aimed to investigate whether ODNs are differently protected against enzymatic degradation in PEI and polyethylene glycol-polyethyleneimine (PEG-PEI) polyplexes. Using fluorescence resonance energy transfer combined with fluorescence correlation spectroscopy, we found that PEI/ODN polyplexes remain to protect the ODNs they carry over a prolonged period of time while in PEG-PEI/ODN polyplexes the degradation of the ODNs slowly proceeds. We attribute this to the fact that PEI seems to compact the ODNs more firmly in the polyplexes' core than PEG-PEI, which apparently also results in a better protection against enzymatic degradation. These observations may also influence the efficiency of PEI-based ODN delivery in vivo, where pegylation is an attractive strategy to enhance the stability of the polyplexes in the blood stream.