Aminopeptidases activate bradykinin and degrade many inflammatory peptides.

No abstract available

Formulations for nasal drug delivery often rely on water sorption to adhere to the mucosa, which also causes a higher water gradient over the tissue and subsequent dehydration. The primary aim of this study was therefore to evaluate mucosal response to dehydration and resolve the hypothesis that mucoadhesion achieved through water sorption could also be a constraint for drug absorption via the nasal route. The effect of altering water activity of the vehicle on Xylometazoline HCl and 51Cr-EDTA uptake was studied separately ex vivo using flow through diffusion cells and excised porcine mucosa. We have shown that a modest increase in the water gradient over mucosa induces a substantial decrease in drug uptake for both Xylometazoline HCl and 51Cr-EDTA. A similar result was obtained when comparing two different vehicles on the market; Nasoferm® (Nordic Drugs, Sweden) and BLOX4® (Bioglan, Sweden). Mucoadhesion based on water sorption can slow down drug uptake in the nasal cavity. However, a clinical study is required to determine whether prolonged duration of the vehicle in situ or preventing dehydration of the mucosa is the most important factor for improving bioavailability.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by TH2-skewed inflammation and increased colonization by Staphylococcus aureus. IFN-λ1 is known for its antiviral activity, but there is little information on its antibacterial role.

Intermittent hypoxia (IH) is characterized by hypoxia-reoxygenation, reported to be a critical risk factor for obstructive sleep apnea (OSA). This experiment aimed to evaluate the direct effects of IH on the human nasal mucosa.

The intranasal administration of proteins using nanoparticles is a promising approach for several applications, especially for mucosal vaccines. Delivery of protein within the epithelial barrier is a key point to elicit an immune response and nano-carrier has to show no toxicity. The aim of this work was to elucidate the interactions of cationic porous nanoparticles loaded with protein delivery for antigen delivery in the nose. We investigated the loading, the cellular delivery and the epithelial transcytosis of proteins associated to these nanoparticles containing an anionic lipid in their core (NPL). NPL were highly endocytosed by airway epithelial cells and significantly improved the protein delivery into the cell. In vitro transcytosis studies showed that NPL did not modify the in vitro epithelial permeability suggesting no toxicity of these carriers. Moreover protein and NPL did not translocate the epithelial barrier. In vivo studies demonstrated that NPL prolonged the nasal residence time of the protein and no NPL were found beyond the epithelial barrier in vivo, precluding a negative side effect. All together these results establish the NPL as a bio-eliminable and optimal vaccine carrier.

Nanoparticles may provide unique therapeutic opportunities when administered via the nasal cavity, yet the primary uptake and transfer pathways for these particles within the nasal mucosa are not well understood. The endocytic pathways involved in the uptake of fluorescently labeled, (Nile Red) solid lipid nanoparticles (SLNs) of different sizes (~30, 60, and 150 nm) were studied using excised bovine olfactory and nasal respiratory tissues. Endocytic activity contributing to nanoparticle uptake was investigated using a variety of pharmacological inhibitors, but none of the inhibitors were able to completely eliminate the uptake of the SLNs. The continued uptake of nanoparticles following exposure to individual inhibitors suggests that a number of endocytic pathways work in combination to transfer nanoparticles into the nasal mucosa. Following exposure to the general metabolic inhibitors, 2,4-DNP and sodium azide, additional, non-energy-dependent pathways for nanoparticle uptake were also observed. While the smallest nanoparticles (30 nm) were the most resistant to the effects of pharmacologic inhibitors, the largest (150 nm) were still able to transfer significant amounts of the particles into the tissues. The rapid nanoparticle uptake observed demonstrates that these lipid particles are promising vehicles to accomplish both local and systemic drug delivery following nasal administration.

Psychological stress exacerbates mast cell (MC)-dependent inflammation, including nasal allergy, but the underlying mechanisms are not thoroughly understood. Because the key stress-mediating neurohormone, corticotropin-releasing hormone (CRH), induces human skin MC degranulation, we hypothesized that CRH may be a key player in stress-aggravated nasal allergy. In the current study, we probed this hypothesis in human nasal mucosa MCs (hM-MCs) in situ using nasal polyp organ culture and tested whether CRH is required for murine M-MC activation by perceived stress in vivo. CRH stimulation significantly increased the number of hM-MCs, stimulated both their degranulation and proliferation ex vivo, and increased stem cell factor (SCF) expression in human nasal mucosa epithelium. CRH also sensitized hM-MCs to further CRH stimulation and promoted a pro-inflammatory hM-MC phenotype. The CRH-induced increase in hM-MCs was mitigated by co-administration of CRH receptor type 1 (CRH-R1)-specific antagonist antalarmin, CRH-R1 small interfering RNA (siRNA), or SCF-neutralizing antibody. In vivo, restraint stress significantly increased the number and degranulation of murine M-MCs compared with sham-stressed mice. This effect was mitigated by intranasal antalarmin. Our data suggest that CRH is a major activator of hM-MC in nasal mucosa, in part via promoting SCF production, and that CRH-R1 antagonists such as antalarmin are promising candidate therapeutics for nasal mucosa neuroinflammation induced by perceived stress.

Allergic rhinitis (AR) has been reported to be associated with chronic rhinosinusitis (CRS). The objective of this study was to investigate the effect of AR on nasal mucosa remodeling in CRS.

Wound healing of the nasal mucosa after endoscopic sinus surgery (ESS) is frequently complicated by scaring and consequently recurrences are encountered. Methods of optimizing results have been sought. In the present study we evaluated the effects of a powerful antioxidant, astaxanthin, on nasal mucosa healing after surgery, comparing it to the extensively studied properties of dexamethasone.

As one of the main environmental stressors commonly found in closed pig houses, ammonia poses high risks to the well-being of humans and animals. This study is aimed at assessing the toxicity of ammonia exposure (80 ppm for 12 days) on the nasal mucosa in piglets. Firstly, we found that after ammonia exposure, the number of white blood cells significantly increased and the serum levels of cytokine IL-4 were significantly decreased. Then, histological analyses showed significant thickening of nasal mucosa and excessive mucus production in the exposure group. Finally, RNA-seq analyses demonstrated that the ammonia exposure disturbed the transcriptome of nasal mucosa which revealed 176 upregulated genes and 426 downregulated genes. GO and KEGG pathway enrichment analysis of the DEGs showed that the upregulated genes were mainly related to neutrophil chemotaxis and immune response, while 80 out of the 426 downregulated genes including CCDCs, CFAPs, DNAHs, and TEKTs were enriched in the microtubule cytoskeleton and cilium morphogenesis/movement. All these results indicated that ammonia exposure induces nasal mucosal hyperplasia and cilia dysfunction, as well as a systemic inflammatory response in piglets. These findings provide new evidence for understanding the damage mechanism of ammonia on the nasal mucosa.

Endoscopic sinus surgery is an effective surgical procedure for treating chronic sinusitis; however, extensive exposure of the bone in the nasal cavity can result in permanent disability postoperatively. Particularly, closure of the sinus drainage pathway due to bone hyperplasia associated with bone exposure can trigger the recurrence of sinusitis. It is essential to regenerate the nasal mucosa after surgery to avoid bone hyperplasia. Regenerative medicine, including cell therapy, could be one of the leading options for nasal mucosa regeneration. To date, there is a lack of effective models for evaluating treatments for prevention of bone hyperplasia that occurs after sinus surgery. The purpose of this study was to develop a model of nasal mucosal removal to evaluate cellular therapies.

Chronic rhinosinusitis without nasal polyps (CRSsNP) is the main type of Chronic rhinosinusitis (CRS) and is a common otorhinolaryngologic disease worldwide. However, the mechanisms of CRSsNP remain poorly understood. In this study, C57BL/6J wild-type and urokinase-type plasminogen activator (uPA) gene knockout (uPA-/-) mice were used to construct the CRSsNP model. Primary human nasal epithelial cells (HNEC) were isolated from CRSsNP patient and treated with uPA knockdown/overexpression lentivirus. CCK-8 and Annexin-V/PI staining were used to detected cell proliferation and apoptosis. In vivo, we found that uPA depletion alleviated mucosal inflammation in the CRSsNP mice model. Wnt inhibitory factor 1 (WIF1) was upregulated in the uPA-/- CRSsNP mice model. In vitro, inhibition of uPA increased cell proliferation and decreased cell apoptosis. Mechanistically, uPA depletion upregulated WIF1 and BCL2 expression, and reduced the expression level of BAX in CRSsNP HNEC. In contrast, decreased cell proliferation and increased cell apoptosis were observed after uPA overexpression. Consistently, a reduction in WIF1 and BCL2 expression levels and an increase in the BAX expression level were observed upon uPA ectopic expression. Furthermore, WIF1 overexpression rescued the effects caused by uPA overexpression in vitro. In conclusion, uPA affects the CRSsNP nasal mucosal epithelium cell apoptosis by upregulating WIF1. To our knowledge, this is the first study to explore the role of uPA in CRSsNP to date.

Mechanical trauma to the nasal mucosa increases the risk of synechia formation, especially after chronic rhinosinusitis and nasal surgeries.

Staphylococcus aureus (S. aureus) plays an important role in the pathogenesis of severe chronic airway disease, such as nasal polyps. However the mechanisms underlying the initiation of damage and/or invasion of the nasal mucosa by S. aureus are not clearly understood. The aim of this study was to investigate the interaction between S. aureus and herpes simplex virus type 1 (HSV1) in the invasion of the nasal mucosa and nasal polyp tissue.

Extra-vascular molecular clearance routes from the brain and cerebrospinal fluid (CSF) remain insufficiently characterized in humans. Animal studies consistently suggest that the cribriform plate and nasal lymphatic vessels are crucial for molecular clearance from CSF. In this study, we aimed to examine human in vivo transport of a CSF tracer from CSF to nasal mucosa. We hypothesised a CSF tracer would enrich in nasal mucosa provided that nasal lymphatic drainage has a significant role in CSF molecular clearance. Consecutive magnetic resonance imaging during 48 h after intrathecal administration of a tracer (gadobutrol) was performed in 24 patients. Despite a strong enrichment of CSF tracer in CSF spaces nearby the cribriform plate, there was no significant enrichment of CSF tracer in nasal mucosa, as measured in superior, medial and inferior turbinates, or in the nasal septum. Therefore, this in vivo study questions the importance of CSF drainage to the human nasal mucosa and emphasizes the need of further human studies.

The host-microbial commensalism can shape the innate immune responses in respiratory mucosa and nasal microbiome also modulates front-line immune mechanism in the nasal mucosa. Inhaled allergens encounter the host immune system first in the nasal mucosa, and microbial characteristics of nasal mucus directly impact the mechanisms of initial allergic responses in nasal epithelium. However, the roles of the nasal microbiome in allergic nasal mucosa remain uncertain. We sought to determine the distribution of nasal microbiomes in allergic nasal mucosa and elucidate the interplay between nasal microbiome Staphylococcus species and Th2 cytokines in allergic rhinitis (AR) models.

Host-microbial commensalism can shape the innate immune response in the nasal mucosa, and the microbial characteristics of nasal mucus directly impact the mechanisms of the initial allergic responses in the nasal epithelium. We sought to determine alterations of the microbial composition in the nasal mucus of patients with allergic rhinitis (AR) and to elucidate the interplay between dysbiosis of the nasal microbiome and allergic inflammation.

Allergic rhinitis (AR) is one of the most common allergic diseases. The results of recent studies of HLA-DRB1 suggest that HLA-DRB1 plays an important role in allergic disease.

Intranasal administration provides a non-invasive drug delivery route that has been proposed to target macromolecules either to the brain via direct extracellular cranial nerve-associated pathways or to the periphery via absorption into the systemic circulation. Delivering drugs to nasal regions that have lower vascular density and/or permeability may allow more drug to access the extracellular cranial nerve-associated pathways and therefore favor delivery to the brain. However, relative vascular permeabilities of the different nasal mucosal sites have not yet been reported. Here, we determined that the relative capillary permeability to hydrophilic macromolecule tracers is significantly greater in nasal respiratory regions than in olfactory regions. Mean capillary density in the nasal mucosa was also approximately 5-fold higher in nasal respiratory regions than in olfactory regions. Applying capillary pore theory and normalization to our permeability data yielded mean pore diameter estimates ranging from 13-17 nm for the nasal respiratory vasculature compared to <10 nm for the vasculature in olfactory regions. The results suggest lymphatic drainage for CNS immune responses may be favored in olfactory regions due to relatively lower clearance to the bloodstream. Lower blood clearance may also provide a reason to target the olfactory area for drug delivery to the brain.