Self-Assembling Lecithin-Based Mixed Polymeric Micelles for Nose to Brain Delivery of Clozapine: In-vivo Assessment of Drug Efficacy via Radiobiological Evaluation.

Purpose: The research objective is to design intranasal brain targeted CLZ loaded lecithin based polymeric micelles (CLZ- LbPM) aiming to improve central systemic CLZ bioavailability. Methods: In our study, intranasal CLZ loaded lecithin based polymeric micelles (CLZ- LbPM) were formulated using soya phosphatidyl choline (SPC) and sodium deoxycholate (SDC) with different CLZ:SPC:SDC ratios via thin film hydration technique aiming to enhance drug solubility, bioavailability and nose to brain targeting efficiency. Optimization of the prepared CLZ-LbPM using Design-Expert® software was achieved showing that M6 which composed of (CLZ:SPC: SDC) in respective ratios of 1:3:10 was selected as the optimized formula. The optimized formula was subjected to further evaluation tests as, Differential Scanning Calorimetry (DSC), TEM, in vitro release profile, ex vivo intranasal permeation and in vivo biodistribution. Results: The optimized formula with the highest desirability exhibiting (0.845), small particle size (12.23±4.76 nm), Zeta potential of (-38 mV), percent entrapment efficiency of > 90% and percent drug loading of 6.47%. Ex vivo permeation test showed flux value of 27 µg/cm².h and the enhancement ratio was about 3 when compared to the drug suspension, without any histological alteration. The radioiodinated clozapine ([131I] iodo-CLZ) and radioiodinated optimized formula ([131I] iodo-CLZ-LbPM) were formulated in an excellent radioiodination yield more than 95%. In vivo biodistribution studies of [131I] iodo-CLZ-LbPM showed higher brain uptake (7.8%± 0.1%ID/g) for intranasal administration with rapid onset of action (at 0.25 h) than the intravenous formula. Its pharmacokinetic behavior showed relative bioavailability, direct transport percentage from nose to brain and drug targeting efficiency of 170.59%, 83.42% and 117% respectively. Conclusion: The intranasal self-assembling lecithin based mixed polymeric micelles could be an encouraging way for CLZ brain targeting.

Human placental extract regulates polarization of macrophages via IRGM/NLRP3 in allergic rhinitis.

Allergic rhinitis (AR) is globally prevalent and its pathogenesis remains unclear. Alternative activation of macrophages is suggested in AR and thought to be involved in natural immunoregulatory processes in AR. Aberrant activation of Nod-like receptor protein 3 (NLRP3) inflammasome is linked with AR. Human placenta extract (HPE) is widely used in clinics due to its multiple therapeutic potential carried by diverse bioactive molecules in it. We aim to investigate the effect of HPE on AR and the possible underlying mechanism. Ovalbumin (OVA)-induced AR rat model was set up and treated by HPE or cetirizine. General manifestation of AR was evaluated along with the histological and biochemical analysis performed on rat nasal mucosa. A proteomic analysis was performed on AR rat mucosa. Mouse alveolar macrophages (MH-S cells) were cultured under OVA stimulation to investigate the regulation of macrophages polarization. The morphological changes and the expression of NLRP3 inflammasome and immunity-related GTPase M (IRGM) in nasal mucosa as well as in MH-S cells were evaluated respectively. The results of our study showed the general manifestation of AR along with the histological changes in nasal mucosa of AR rats were improved by HPE. HPE suppresses NLRP3 inflammasome and the decline of IRGM in AR rats and MH-S cells. HPE regulates macrophage polarization through IRGM/NLRP3. We demonstrated that HPE had protection for AR and the protection is achieved partly through suppressing M1 while promoting M2, the process which is mediated by IRGM via inhibiting NLRP3 inflammasome in AR.

SARS-CoV-2 and the nose: Risks and implications for primary care.

BACKGROUND: General practitioners (GPs) have some of the highest rates of mortality from COVID-19 among healthcare workers. SARS-CoV-2 has unique properties that place GPs at particular risk. OBJECTIVE: The aim of this article is to discuss the nose-related features of SARS-CoV-2 that place GPs at risk, and to make recommendations pertinent to the safety and protection of primary healthcare physicians. DISCUSSION: The highest viral load of SARS-CoV-2 is in the nose and nasopharynx. It is often highest early in the illness, before the development of symptoms. Further, SARS-CoV-2 replicates and continues to shed in the nasopharynx long after the virus is no longer detectable in the lower respiratory tract. This places any physician performing examinations on, or procedures involving, the upper respiratory tract at risk for contracting COVID-19. New-onset hyposmia and dysgeusia are indicators for COVID-19 and should be included in screening protocols.

Evaluation of both exonic and intronic variants for effects on RNA splicing allows for accurate assessment of the effectiveness of precision therapies.

Elucidating the functional consequence of molecular defects underlying genetic diseases enables appropriate design of therapeutic options. Treatment of cystic fibrosis (CF) is an exemplar of this paradigm as the development of CFTR modulator therapies has allowed for targeted and effective treatment of individuals harboring specific genetic variants. However, the mechanism of these drugs limits effectiveness to particular classes of variants that allow production of CFTR protein. Thus, assessment of the molecular mechanism of individual variants is imperative for proper assignment of these precision therapies. This is particularly important when considering variants that affect pre-mRNA splicing, thus limiting success of the existing protein-targeted therapies. Variants affecting splicing can occur throughout exons and introns and the complexity of the process of splicing lends itself to a variety of outcomes, both at the RNA and protein levels, further complicating assessment of disease liability and modulator response. To investigate the scope of this challenge, we evaluated splicing and downstream effects of 52 naturally occurring CFTR variants (exonic = 15, intronic = 37). Expression of constructs containing select CFTR intronic sequences and complete CFTR exonic sequences in cell line models allowed for assessment of RNA and protein-level effects on an allele by allele basis. Characterization of primary nasal epithelial cells obtained from individuals harboring splice variants corroborated in vitro data. Notably, we identified exonic variants that result in complete missplicing and thus a lack of modulator response (e.g. c.2908G>A, c.523A>G), as well as intronic variants that respond to modulators due to the presence of residual normally spliced transcript (e.g. c.4242+2T>C, c.3717+40A>G). Overall, our data reveals diverse molecular outcomes amongst both exonic and intronic variants emphasizing the need to delineate RNA, protein, and functional effects of each variant in order to accurately assign precision therapies.

In vivo assessment of cerebrospinal fluid efflux to nasal mucosa in humans.

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.

Incorporating ToxCast™ data into naphthalene human health risk assessment.

Chronic inhalation of naphthalene causes nasal olfactory epithelial tumors in rats and benign lung adenomas in mice. The available human data do not establish an association between naphthalene and increased respiratory cancer risk. Therefore, cancer risk assessment of naphthalene in humans depends predominantly on experimental evidence from rodents. The United States Environmental Protection Agency's (US EPA) Toxicity Forecaster (ToxCast™) database contains data from 710 in vitro assays for naphthalene, the majority of which were conducted in human cells. Of these assays, only 18 were active for naphthalene, and all were in human liver cells. No assays were active in human bronchial epithelial cells. In our analysis, all of the active naphthalene ToxCast assay data were reviewed and used to: 1) determine naphthalene human inhalation concentrations corresponding to relevant activity concentrations for all active naphthalene assays, using a physiologically based pharmacokinetic (PBPK) model; and 2) evaluate the transcriptional responses for active assays in the context of consistency with the larger naphthalene data set and proposed modes of action (MoAs) for naphthalene toxicity and carcinogenicity. The transcriptional responses in liver cells largely reflect cellular activities related to oxidative stress and chronic inflammation. Overall, the results from our analysis of the active ToxCast assays for naphthalene are consistent with conclusions from our earlier weight-of-evidence evaluation for naphthalene carcinogenesis.

Pre-Clinical Assessment of the Nose-to-Brain Delivery of Zonisamide After Intranasal Administration.

PURPOSE: Zonisamide clinical indications are expanding beyond the classic treatment of epileptic seizures to Parkinson's disease and other neurodegenerative diseases. However, the systemic safety profile of zonisamide may compromise its use as a first-line drug in any clinical condition. Since zonisamide is marketed as oral formulations, the present study aimed at exploring the potential of the intranasal route to centrally administer zonisamide, evaluating the systemic bioavailability of zonisamide and comparing its brain, lung and kidney pharmacokinetics after intranasal, oral and intravenous administrations. METHODS: In vitro cell studies demonstrated that zonisamide and proposed thermoreversible gels did not affect the viability of RPMI 2650 or Calu-3 cells. Thereafter, male CD-1 mice were randomly administered with zonisamide by oral (80 mg/kg), intranasal or intravenous (16.7 mg/kg) route. At predefined time points, animals were sacrificed and plasma and tissues were collected to quantify zonisamide and describe its pharmacokinetics. RESULTS: Intranasal route revealed a low absolute bioavailability (54.95%) but the highest value of the ratio between the area under the curve (AUC) between brain and plasma, suggesting lower systemic adverse events and non-inferior effects in central nervous system comparatively to intravenous and oral routes. Furthermore, drug targeting efficiency and direct transport percentage into the brain were 149.54% and 33.13%, respectively, corroborating that a significant fraction of zonisamide suffers direct nose-to-brain transport. Lung and kidney exposures obtained after intranasal administration were lower than those observed after intravenous injection. CONCLUSIONS: This pre-clinical investigation demonstrates a direct nose-to-brain delivery of zonisamide, which may be a promising strategy for the treatment of central diseases.

Histamine H4 receptor regulates Th2-cytokine profile through thymic stromal lymphopoietin in allergic rhinitis.

PURPOSE: Epithelial thymic stromal lymphopoietin (TSLP) promotes Th2 inflammatory responses through induction of OX40 ligand (OX40L) on dendritic cells in allergic rhinitis (AR). Emerging evidence supports the important role of histamine H4 receptor (H4R) in allergic inflammation. This study aimed to investigate the effects of H4R in Th2-cytokine profile mediated by TSLP in AR. METHODS: Human nasal epithelial cells (HNECs) from AR patients were stimulated with histamine in the presence or absence of H4R agonist (4-methylhistamine, 4-MH) and antagonist (NJ7777120, JNJ) or H1R agonist (2-pyridylethylamine). TSLP protein was measured by Western blotting and ELISA. To further elucidate the role of H4R in the in vivo situation of experimental AR, rats were sensitized and treated with JNJ or 4-MH. TSLP and OX40 ligand (OX40L) in the nasal mucosa were assayed by Western blotting. Th2 cytokines including interleukin-4, 5 and 13 in nasal lavage fluids were detected by ELISA. RESULTS: Histamine alone did not induce TSLP production by HNECs. The pre-incubation with 4-MH prior to histamine promoted TSLP expression, which was inhibited by the stimulation with JNJ prior to histamine and 4-MH. The pre-incubation with 2-pyridylethylamine before histamine stimulation had no impact on TSLP production. In AR rats, the levels of TSLP and OX40L protein were increased as well as Th2 cytokines, which was further up-regulated by 4-MH treatment, while JNJ treatment attenuated these effects. CONCLUSIONS: H4R activation induced TSLP production by HNECs, which up-regulated OX40L expression in the nasal mucosa of sensitized rats. These factors promoted Th2-cytokine profile in AR.

Ursolic acid loaded intra nasal nano lipid vesicles for brain tumour: Formulation, optimization, in-vivo brain/plasma distribution study and histopathological assessment.

The aim was to formulate an optimized ursolic acid (UA) loaded lipid vesicle using formulation by design approach (FbD) for improving the drug targeting by nasal route for brain tumor. Three factors were evaluated at three different levels using anethole (terpene) (A), ethanol (B) and phospholipid90 G (C) as independent variables and their individual and combined effects were observed for PDI (Y1), vesicle size (Y2) and encapsulation efficiency (Y3) to select an optimal system (UALVopt). The optimized formulation was further converted into gel and evaluated for drug release, nasal permeation study, brain/plasma uptake and histopathology study. The UALVopt formulation containing anethole as terpene (1% as A), ethanol (2.6% as B) and phospholipid90 G (8.8 mg as C) showed low PDI (0.212), vesicle size (115.56 nm) and high entrapment efficiency (76.42%). The in-vitro drug release and ex-vivo permeation study results revealed prolonged drug release and permeation. The brain/blood ratio for UALVGopt remained significantly higher at all the time points with respect to UALVopt indicating higher and prolonged retention of drug at site of action. The histopathological study of the nasal mucosa and brain confirmed non-toxic nature of developed formulation. The formulation UALVGopt could serve as a better alternative for the brain targeting via the intranasal route which in turn could subsequently improve its efficacy.

3-D nasal cultures: Systems toxicological assessment of a candidate modified-risk tobacco product.

In vitro toxicology approaches have evolved from a focus on molecular changes within a cell to understanding of toxicity-related mechanisms in systems that can mimic the in vivo environment. The recent development of three dimensional (3-D) organotypic nasal epithelial culture models offers a physiologically robust system for studying the effects of exposure through inhalation. Exposure to cigarette smoke (CS) is associated with nasal inflammation; thus, the nasal epithelium is relevant for evaluating the pathophysiological impact of CS exposure. The present study investigated further the application of in vitro human 3-D nasal epithelial culture models for toxicological assessment of inhalation exposure. Aligned with 3Rs strategy, this study aimed to explore the relevance of a human 3-D nasal culture model to assess the toxicological impact of aerosols generated from a candidate modified risk tobacco product (cMRTP), the Tobacco Heating System (THS) 2.2, as compared with smoke generated from reference cigarette 3R4F. A series of experimental repetitions, where multiple concentrations of THS2.2 aerosol and 3R4F smoke were applied, were conducted to obtain reproducible measurements to understand the cellular/molecular changes that occur following exposure. In agreement with "Toxicity Testing in the 21st Century - a Vision and a Strategy", this study implemented a systems toxicology approach and found that for all tested concentrations the impact of 3R4F smoke was substantially greater than that of THS2.2 aerosol in terms of cytotoxicity levels, alterations in tissue morphology, secretion of pro-inflammatory mediators, impaired ciliary function, and increased perturbed transcriptomes and miRNA expression profiles.

Sinonasal symptom assessment by the self-reported DyNaChron questionnaire: Before or after consultation?

OBJECTIVE: Assessment of sinonasal symptoms on a self-reported questionnaire is thoroughly subjective, but indispensable for quantifying symptoms. The present study sought to compare responses on the DyNaChron questionnaire just before and just after consultation for chronic sinonasal dysfunction. MATERIALS AND METHODS: 78 patients (mean age, 43.1±16.9 years) consulting for chronic sinonasal dysfunction took part in a prospective study, responding to the computerized version of the DyNaChron self-reported questionnaire, in a dedicated room, just before and just after medical interview and physical examination. RESULTS: Most patients tended to grade symptoms as less severe after consultation. Significant differences in mean score were found for nasal obstruction (difference of 0.94/10), anterior (0.40) and posterior rhinorrhea (0.26), olfactory disorder (0.65), and facial pain and headache (0.65), but not for chronic cough. CONCLUSION: Self-reported scores for chronic sinonasal dysfunction differ slightly from before to after consultation. They are therefore to be interpreted with caution, taking account of possible factors of bias.

Human barrier models for the in vitro assessment of drug delivery.

In vitro test systems gain increasing importance in preclinical studies to increase the predictivity and reduce animal testing. Of special interest herein are barrier tissues that guard into the human body. These barriers are formed by highly specialized tissues such as the skin, the airways, and the intestine. However, to recapitulate these tissues, researchers are currently restricted by a lack of suitable supporting scaffolds. In this study, we present biological scaffolds based on decellularized porcine gut segments that offer a natural environment for cell growth and differentiation. Employing these scaffolds, human barrier models of the skin, the airways, and the intestine that mimic the natural histological architecture of the respective tissue are generated. These models show tissue specific barrier properties, such as the stratification of the skin, the mucociliary phenotype of the airways, and polarization of the intestinal epithelium. To investigate the transport characteristics of the intestinal test system, we incubated the tissue models with fluorescein (P app <1 × 106 cm/s), propranolol (P app >7 × 106 cm/s), and rhodamin123 (ratio 2.45). The here presented biological scaffolds facilitate the in vitro generation of human barrier models that might represent useful tools for drug delivery studies.

Evaluation of the Tobacco Heating System 2.2. Part 7: Systems toxicological assessment of a mentholated version revealed reduced cellular and molecular exposure effects compared with mentholated and non-mentholated cigarette smoke.

Modified risk tobacco products (MRTPs) are being developed with the aim of reducing smoking-related health risks. The Tobacco Heating System 2.2 (THS2.2) is a candidate MRTP that uses the heat-not-burn principle. Here, systems toxicology approaches were engaged to assess the respiratory effects of mentholated THS2.2 (THS2.2M) in a 90-day rat inhalation study (OECD test guideline 413). The standard endpoints were complemented by transcriptomics and quantitative proteomics analyses of respiratory nasal epithelium and lung tissue and by lipidomics analysis of lung tissue. The adaptive response of the respiratory nasal epithelium to conventional cigarette smoke (CS) included squamous cell metaplasia and an inflammatory response, with high correspondence between the molecular and histopathological results. In contrast to CS exposure, the adaptive tissue and molecular changes to THS2.2M aerosol exposure were much weaker and were limited mostly to the highest THS2.2M concentration in female rats. In the lung, CS exposure induced an inflammatory response, triggered cellular stress responses, and affected sphingolipid metabolism. These responses were not observed or were much lower after THS2.2M aerosol exposure. Overall, this system toxicology analysis complements and reconfirms the results from classical toxicological endpoints and further suggests potentially reduced health risks of THS2.2M.

Usefulness of oxidative stress biomarkers evaluated in the snout scraping, serum and Peripheral Blood Cells of Crocodylus moreletii from Southeast Campeche for assessment of the toxic impact of PAHs, metals and total phenols.

In this study, we assessed the effects of inorganic and organic pollutants [As, Cu, Fe, Mn, Pb, Zn, PAHs (11 compounds) and total phenols] from a panel of biomarkers [O2, H2O2, thiobarbituric acid reactive substances (TBARS), carbonyl proteins (RCO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total cytochrome P450 activities] evaluated in the Snout Scraping (SS), Serum (S) and Peripheral Blood Cells (PBC) of the Morelet's crocodile (Crocodylus moreletii) inhabiting the reference locality (Lake Mocu) and polluted locality (Champoton River) using Principal Component Analysis (PCA). In male crocodiles from the reference site, only H2O2 in PBC was related to levels of fluoranthene on the Keel of Caudal Scales (KCS), but, in females, no association was detected. In contrast, a sex-linked response was detected in specimens from the polluted locality. Levels of benzo[a]pyrene, benzo[a]anthracene, chrysene, pyrene, phenanthrene, acenaphthene, Zn, Cu, and Pb in KCS of the female crocodil were related to the oxidative stress biomarkers on PBC, incluing the total CYP450 activity and levels of O2, H2O2 in serum. However, in male crocodiles, the oxidative stress in SS and in the serum (TBARS, RCO, CAT, GPx), and SOD in PBC was related to As, Pb, Cu, Fe, and benzo[a]pyrene water concentrations and to the burdens of As, Fe, Mn, indeno[1,2,3cd]pyrene in KCS. These results confirm the usefulness of minimal or non-invasive methods of evaluating the oxidative stress response for the environmental monitoring program on the wild Morelet's crocodile that is subject to special protection in Mexican guidelines.

Visualization and Quantitative Assessment of the Brain Distribution of Insulin through Nose-to-Brain Delivery Based on the Cell-Penetrating Peptide Noncovalent Strategy.

Our recent work suggested that intranasal coadministration with the cell-penetrating peptide (CPP) penetratin increased the brain distribution of the peptide drug insulin. The present study aimed to distinctly certify the ability of penetratin to facilitate the nose-to-brain delivery of insulin by quantitatively evaluating the distribution characteristics in brain using radioactive (64)Cu-NODAGA-insulin. Autoradiography and analysis using a gamma counter of brain areas demonstrated that the accumulation of radioactivity was greatest in the olfactory bulb, the anterior part of the brain closest to the administration site, at 15 min after intranasal administration of (64)Cu-NODAGA-insulin with l- or d-penetratin. The brain accumulation of (64)Cu-NODAGA-insulin with penetratin was confirmed by ELISA using unlabeled insulin in which intact insulin was delivered to the brain after intranasal coadministration with l- or d-penetratin. By contrast, quantification of cerebrospinal fluid (CSF) samples showed increased insulin concentration in only the anterior portion of the CSF at 15 min after intranasal coadministration with l-penetratin. This study gives the first concrete proof that penetratin can accelerate the direct transport of insulin from the nasal cavity to the brain parenchyma. Further optimization of intranasal administration with CPP may increase the efficacy of delivery of biopharmaceuticals to the brain while reducing the risk of systemic drug exposure.

PLGA/DPPC/trimethylchitosan spray-dried microparticles for the nasal delivery of ropinirole hydrochloride: in vitro, ex vivo and cytocompatibility assessment.

In the present study we investigated polymer-lipid microparticles loaded with ropinirole hydrochloride (RH) for nasal delivery. RH microparticles were further evaluated by means of scanning electron microscopy (SEM), ζ-potential measurements, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD). In vitro release studies were performed in simulated nasal electrolyte solution (SNES) pH5.5 at 35°C. Ex vivo permeation studies were conducted across sheep nasal mucosa. Cytocompatibility was tested in cultured human airway epithelial cells (Calu-3). SEM studies revealed spheroid microparticles in the range of 2.09µm to 2.41µm. The presence of trimethylchitosan (TMC) induced a slight shift towards less negative ζ-potential values. Surface chemistry (XPS) revealed the presence of dipalmitoylphospatidylcholine (DPPC) and poly(lactic-co-glycolic acid) (PLGA) onto microparticles' surface, further corroborating the FT-IR and XRD findings. In vitro release studies showed that the microparticle composition can partly modulate the release of RH. Ex vivo studies demonstrated a 2.35-folded enhancement of RH permeation when RH was co-formulated with TMC of low molecular weight, compared to the control. All formulations tested were found to be non-toxic to cells. The results suggest that polymer-lipid microparticles may be a promising carrier for the nasal delivery of RH.

Ufasomes nano-vesicles-based lyophilized platforms for intranasal delivery of cinnarizine: preparation, optimization, ex-vivo histopathological safety assessment and mucosal confocal imaging.

To circumvent the low and erratic absorption of orally administrated cinnarizine (CN), intranasal lyophilized gels containing unsaturated fatty acid liposomes (ufasomes) and encapsulating CN were prepared from oleic acid using a simple assembling strategy. The effects of varying drug concentration and cholesterol percentage on ufasomes size, polydispersity index and entrapment efficiency were investigated using 3(1)4(1) full factorial design. The optimized ufasomes that contained 14% cholesterol relative to oleic acid displayed spherical morphology with average size of 788 nm and entrapment efficiency of 80.49%. To overcome the colloidal instability of CN-loaded ufasomes dispersions and their short residence time in the nasal cavity, the ufasomes were incorporated into mucoadhesive hydrogels that were lyophilized into unit dosage forms for accurate dosing. Scanning electron micrographs of the lyophilized gel revealed that the included ufasomes were intact, non-aggregating and maintained their spherical morphology. Rheological characterization of reconstituted ufasomal lyophilized gel ensured ease of application. Furthermore, the gel induced minor histopathological alterations in sheeps' nasal mucosa. Ex-vivo confocal laser imaging confirmed the ability of ufasomes to penetrate deep through nasal mucosa layers. The results highlighted in the current work confirm the feasibility of using CN-loaded ufasomal gels for intranasal drug delivery.

The role of MMP-2, MMP-9, and TIMP-1 in the pathogenesis of nasal polyps: Immunohistochemical assessment at eight different levels in the epithelial, subepithelial, and deep layers of the mucosa.

We conducted a prospective study to investigate the role of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the pathogenesis of nasal polyps. Our study group consisted of 24 patients-21 men and 3 women, aged 23 to 70 years (mean: 45.97 ± 11.60)-with nasal polyposis who underwent functional endoscopic sinus surgery. For comparison purposes, we assembled a control group of 11 patients-6 men and 5 women, aged 18 to 56 years (mean: 29.90 ± 14.22)-without nasal polyps who underwent septoplasty and/or rhinoplasty. We analyzed 36 polyp specimens obtained from the study group (10 from the nasal cavity, 10 from the maxillary sinus, and 16 from the ethmoid sinus) and 11 tissue specimens from the control group (each control provided 1 specimen from the inferior turbinate). We then calculated the mean number of these cells in the epithelium, subepithelial layer of the lamina propria, and the deep paraglandular layer of the mucosa. In general, we found that MMP-2, MMP-9, and TIMP-1 values were higher in the nasal polyp group. These differences became less so as patients' ages and the duration of polyps increased. We conclude that the most important role that MMP-2 plays in polyp growth may be in terms of perivascular localization and an increase in vascular permeability, which causes inflammatory cell migration and edema in the extracellular matrix. An increase in MMP-2 in glandular tissue may lead to hydrolysis of tissue matrix components. The degraded extracellular matrix may result in fibrosis of the polyps. An increase of MMP-9 in the apical part of the epithelium in the polypoid tissue of the nasal cavity, maxillary sinus, and ethmoid sinus may facilitate the epithelial and endothelial cell migration that is observed during polyp development and growth.

Assessment of epithelial innate antimicrobial factors in sinus tissue from patients with and without chronic rhinosinusitis.

BACKGROUND: Airway secretions contain endogenous antimicrobial factors (AMFs) that contribute to the innate host defense of the respiratory tract. Antibacterial peptides as well as host-derived lipids including cholesteryl esters have been detected in maxillary lavage fluid. Sterol O-acyltransferase 1 (SOAT1) is a key enzyme in cholesteryl ester production. The purpose of this study is to determine if such intrinsic microbicidal molecules are acutely expressed within sinus tissue and to compare levels of expression between patients with and without chronic rhinosinusitis (CRS). METHODS: Sinus tissue was obtained from subjects with (24) and without (9) a history of CRS. Six CRS patients had nasal polyposis (CRSwNP). Immunofluorescence staining for human neutrophil peptide (HNP) was done as a marker for inflammation. Real-time polymerase chain reaction (RT-PCR) following RNA extraction was used to quantify the expression of SOAT-1, the epithelial beta-defensins (HBD2 and HBD3), and the cathelicidin LL37 with ribosomal protein, large, P0 (RPLP0) as the housekeeping gene. RESULTS: Immunofluorescence showed significant increase in HNP staining in CRS patients without nasal polyposis (CRSsNP) vs non-CRS specimens (p = 0.010), in agreement with clinical inflammation status. SOAT1 messenger RNA (mRNA) expression was also upregulated in CRSsNP compared to non-CRS (p = 0.041) and CRSwNP (p = 0.005) patients, whereas increases for HBD2 and HBD3 were less prominent. LL37 was either absent or expressed at very low levels in all samples. CONCLUSION: Increased biosynthesis of SOAT1, a key enzyme for antimicrobial cholesteryl ester production, was observed in the sinus tissue of CRSsNP patients but not in CRSwNP patients. This further supports the novel concept of lipid-mediated innate mucosal defense and delineates CRS with and without nasal polyposis as distinct subtypes.

A 26-Week Toxicity Assessment of AIR001 (Sodium Nitrite) by Inhalation Exposure in Rats and by Intravenous Administration in Dogs.

Historically, nitrogen oxides (NOx) in food, drinking water, as well as in the atmosphere have been believed to be associated with adverse health consequences. More recently, NOx have been implicated in normal homeostatic regulation, and exogenous administration has been associated with health benefits. One such potential health benefit is the prospect that inhaled nitrite will lower pulmonary blood pressure (BP) in patients with pulmonary arterial hypertension (PAH), a disease with poor prognosis due to the lack of effective treatment. To characterize potential chronic toxicity associated with inhaled AIR001 (sodium nitrite) for use in the treatment of PAH, 26-week exposures to AIR001 were carried out by inhalation administration in rats and by intravenous infusion in dogs. The studies revealed that methemoglobinemia was the primary adverse effect in both species. Methemoglobin levels less than 40% were well tolerated in both species, while levels greater than 50% methemoglobin caused death in some rats. Additionally, a decrease in systemic BP was also observed with inhaled AIR001 exposure in dogs. These acute secondary and exaggerated pharmacological effects occurred daily throughout the 26-week treatment period. Chronic exposure did not alter the magnitude of either methemoglobinemia or hypotension or result in additional toxicity or compensatory responses. Based on the exposure levels that produced these pharmacodynamic responses in animals, relative to those measured in early clinical studies, it appears that an adequate margin of safety exists to support the continued clinical development of inhaled AIR001.