Retinoic acid and hydrocortisone strengthen the barrier function of human RPMI 2650 cells, a model for nasal epithelial permeability

The nasal pathway represents an alternative route for non-invasive systemic administration of drugs. The main advantages of nasal drug delivery are the rapid onset of action, the avoidance of the first-pass metabolism in the liver and the easy applicability. In vitro cell culture systems offer an opportunity to model biological barriers. Our aim was to develop and characterize an in vitro model based on confluent layers of the human RPMI 2650 cell line. Retinoic acid, hydrocortisone and cyclic adenosine monophosphate, which influence cell attachment, growth and differentiation have been investigated on the barrier formation and function of the nasal epithelial cell layers. Real-time cell microelectronic sensing, a novel label-free technique was used for dynamic monitoring of cell growth and barrier properties of RPMI 2650 cells. Treatments enhanced the formation of adherens and tight intercellular junctions visualized by electron microscopy, the presence and localization of junctional proteins ZO-1 and β-catenin demonstrated by fluorescent immunohistochemistry, and the barrier function of nasal epithelial cell layers. The transepithelial resistance of the RPMI 2650 cell model reached 50 to 200 Ω × cm², the permeability coefficient for 4.4 kDa FITC-dextran was 9.3 to 17 × 10⁻⁶ cm/s, in agreement with values measured on nasal mucosa from in vivo and ex vivo experiments. Based on these results human RPMI 2650 cells seem to be a suitable nasal epithelial model to test different pharmaceutical excipients and various novel formulations, such as nanoparticles for toxicity and permeability.

Electronic supplementary material

The online version of this article (doi:10.1007/s10616-012-9493-7) contains supplementary material, which is available to authorized users.     

Inspirational airflow patterns in deviated noses: a numerical study

This study attempts to evaluate the effects of deviation of external nose to nasal airflow patterns. Four typical subjects were chosen for model reconstruction based on computed tomography images of undeviated, S-shaped deviated, C-shaped deviated and slanted deviated noses. To study the hypothetical influence of deviation of external nasal wall on nasal airflow (without internal blockage), the collapsed region along the turbinate was artificially reopened in all the three cases with deviated noses. Computational fluid dynamics simulations were carried out in models of undeviated, original deviated and reopened nasal cavities at both flow rates of 167 and 500 ml/s. The shape of the anterior nasal roof was found to be collapsed on one side of the nasal airways in all the deviated noses. High wall shear stress region was found around the collapsed anterior nasal roof. The nasal resistances in cavities with deviated noses were considerably larger than healthy nasal cavity. Patterns of path-line distribution and wall shear stress distribution were similar between original deviated and reopened models. In conclusion, the deviation of an external nose is associated with the collapse of one anterior nasal roof. The crooked external nose induced a larger nasal resistance compared to the undeviated case, while the internal blockage of the airway along the turbinates further increased it.     

Normal nasal cavity and paranasal sinuses in brown lemurs Eulemur fulvus: computed tomography and cross-sectional anatomy

Background Far less is known about the normal anatomy of the nasal cavity of Eulemur fulvus; no computed tomography (CT) scan has ever been published. Methods Relevant CT scans were taken in the transverse, dorsal and longitudinal planes. These scans were compared with anatomical sections of heads. Results Computed tomography scans revealed almost all nasal structures, but cannot differentiate between the various layers of the nasal mucosa. Results show a double‐scroll arrangement of the ventral nasal concha. The dorsal nasal concha protrudes into the maxillary sinus, but no protrusion into the frontal sinus was observed. The ethmoturbinate I is completely closed back on itself and rostrally voluminous. Conclusions This work shows that at a clinical level, the integrity of the different turbinates can easily be appreciated from a simple CT scan. It will assist clinicians to evaluate pathological conditions that affect the nasal region.     

Mechanisms of neutrophil-induced DNA damage in respiratory tract epithelial cells

Reactive oxygen species (ROS) released by neutrophils have been suggested to play an important role in cancer development. Since the mechanisms underlying this effect in the respiratory tract are still unclear, we evaluated DNA damage induced by neutrophils in respiratory tract epithelial cells in vitro and in vivo. For in vitro studies, rat lung epithelial cells (RLE) were co-incubated with activated neutrophils, neutrophil-conditioned medium, or hydrogen peroxide. For in vivo studies, we considered the human nose as a target organ, comparing neutrophilic inflammation in the nasal lavage fluid with the oxidative DNA lesion 8-hydroxydeoxyguanosine (8-OHdG) in epithelial cells obtained by nasal brush. Our in vitro data show that human neutrophils are able to induce both 8-OHdG and strand breaks in DNA from RLE cells. Our data also suggest that DNA damage induced by neutrophils is inhibited when neutrophil-derived H₂O₂ is consumed by myeloperoxidase. In contrast, in the nose no association between neutrophil numbers and 8-OHdG was found. Therefore, it remains unclear whether neutrophils pose a direct genotoxic risk for the respiratory tract epithelium during inflammation, and more in vivo studies are needed to elucidate the possible association between neutrophils and genotoxicity in the lung.     

Sneezing reflex is mediated by a peptidergic pathway from nose to brainstem

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再论南京直立人的高耸鼻梁和气候适应

对南京直立人所具有的高耸鼻梁, 本文作者曾从人鼻的功能、鼻梁高耸程度与气候因素的关系以及因纽特人的鼻对寒冷气候的适应等方面进行过论证,认为是对气候适应的结果。本文从南京直立人的生存年代、若干形态项目的可靠性、人类的适应性以及高耸鼻梁的化石人类谱系对这一问题作进一步的论证。结果表明: 1)尚无可靠的证据能够否定南京直立人是生活在距今58—62万年这一年代测定数据。在南京直立人生存时,欧洲远古人类尚未具有像南京直立人那样的高耸鼻梁; 2)人类高耸鼻梁这一适应性特征的形成会有永久性的影响, 是遗传特征, 其后代即使生活在与其祖先不同的气候环境里, 这个特征也不会马上改变; 3)如果有所谓的Bodo高鼻梁的化石人类谱系存在的话, 则南京直立人的高耸鼻梁与欧洲化石人类的基因或与这个Bodo谱系的基因并无遗传上的关系。一个合理的解释是, 南京直立人的高耸鼻梁不可能意味着西方血统。     

Intranasal immunization of mutant toxic shock syndrome toxin 1 elicits systemic and mucosal immune response against Staphylococcus aureus infection

We investigated whether an intranasal immunization with mutant toxic shock syndrome toxin 1 (TSST-1) could elicit a protective effect against nasal colonization as well as systemic infection of Staphyloccoccus aureus in a mouse model. Anti-TSST-1 antibody production in the mucosal exudates and in sera was efficiently induced. Bacterial numbers were reduced in spleen, liver and also nasal cavities in the early stage of nasal colonization, and the survival rate was significantly improved in the immunized mice. It was suggested that the neutralizing activity of antibodies and the enhanced bactericidal activity of neutrophils were involved in the protection against systemic S. aureus infection, and the secreted antibodies could be involved in reduction of S. aureus bacterial counts in the nasal cavity.     

Mucociliary differentiation according to time in human nasal epithelial cell culture

Knowledge of the state of differentiation, cell phenotype, and expression of genes for mucus production at the time of study is important because these may vary at different times during the culture period. The primary purpose of this study was to determine whether the number of ciliated cells increases as a function of differentiation in NHNE cells. If we observed an increase in the number of ciliated cells, the composition ratio of ciliated and secretory cells according to the culture duration was determined. The levels of mucin and lysozyme secretion and their gene expression at this time were also examined. The presence of ciliated cells was not evident up to 2 days after confluence. However, 3.1 +/- 0.2 %, 7.4 +/- 0.5 %, and 14.5 +/- 0.6 % of the cells were ciliated on the 7th, the 14th, and the 28th day after confluence, respectively. Meanwhile, the percentage of secretory cells were 35.6 +/- 2.8 %, 32.8 +/- 2.5 %, 32.8 +/- 2.5 %, and 49.4 +/- 1.4 % on the 2nd, the 7th, 14th, and 28th day after confluence. The amount of secreted mucin showed an abruptly increasing pattern by the 14th day after confluence but showed no significant changes thereafter. The amount of secreted lysozyme increased as a function of differentiation. MUC5AC and MUC5B mRNA were mainly expressed between the 7th and the 14th day after confluence with relatively weak MUC8 and lysozyme expression. By the 28th day after confluence however, as the MUC5AC mRNA expression became weaker, MUC5B, MUC8, and lysozyme mRNA expression became stronger. In conclusion, we speculate that in in vitro studies with NHNE cells, the time point of treatment should vary according to the purpose of the study. In addition, the MUC5B and MUC8 gene may play an important role in mucin secretion in fully differentiated human nasal epithelial cells.