Untangling the truth: User engagement with misinformation in toothache-related Facebook posts.

OBJECTIVE: Social media is a platform for sharing views on aspects of life, including oral health. This study aimed to characterize Facebook posts related to toothache information. METHODS: Two independent investigators retrieved 500 English-language posts with the highest level of interaction using CrowdTangleTM and analyzed their facticity, motivation, author's profile, content, sentiment, and type of post. Data were analysed descriptively and using Pearson's Chi-square and Mann-Whitney U tests and multiple logistic regression models. RESULTS: Most posts were produced by regular users and were not financially motivated, although commercial posts had significantly higher total interaction among users. While link- or video-containing posts (OR = 1.66) and posts with positive sentiments (OR = 1.53) were associated with users' total interaction, older (OR = 1.81) and link- or video-containing posts (OR = 2.04) were associated with overperforming scores. Misinformation was positively associated with financial motivation (OR = 2.03) and positive sentiments (OR = 3.79). CONCLUSION: This study highlights the importance of addressing the spread of misinformation related to oral health on social media and taking steps to ensure that accurate and reliable information is readily available. Toothache-related misinformation was associated with positive sentiments and financial motivation. Links, videos, and positive sentiments awakened greater user engagements with toothache-related posts.

Why is Pet (cat/dog) allergen immunotherapy (ait) such a controversial topic? current perspectives and future directions.

Summary: Dogs and cats are the most common pets worldwide. In Italy, the prevalence of allergic sensitization to cats and dogs is 16% and 9% respectively. The limited standardization of allergenic extracts, especially for dogs, emphasizes the importance of Component Resolved Diagnosis (CRD) for accurate diagnosis and subsequent prescription of allergen immunotherapy (AIT). However, this low standardization is the main factor contributing to the unsatisfactory clinical efficacy of traditional AIT, AIT with modified allergens, and intralymphatic allergen-specific immunotherapy (ILAIT). Emerging immunological approaches, particularly for controlling the primary cat allergen, show promise but are hindered by high costs (e.g., use of anti-Fel d 1 monoclonal antibodies in humans) or by exclusively targeting Fel d 1 produced by one's own animal (e.g., immunizing cats to induce neutralizing antibodies against Fel d 1 or including an egg product with anti Fel d 1 IgY antibodies in feline diet). Further studies are imperative for standardizing pet allergens, enhancing the efficacy of various AIT modalities, and exploring other immunological approaches, to optimize the relationship between pets and their owners and prevent distressing "forced removals."

Methylation Analysis of Urinary Sample in Non-Muscle-Invasive Bladder Carcinoma: Frequency and Management of Invalid Result.

BACKGROUND: Numerous studies showed that methylation analysis represents a newly developed urinary marker based on DNA methylation changes in a panel of genomic biomarkers and it could represent a valid tool in terms of the diagnosis and prediction of high-grade urothelial carcinoma recurrences. One of the limits of the use of this new molecular method during a follow-up is represented by the number of invalid tests in routine practice. METHOD: A total of 782 patients with a diagnosis of non-muscle-invasive high-grade carcinoma (NMIBC) was studied. The Bladder EpiCheck test (BE) was performed together with cytology in all cases within 1 year after the end of treatment. In 402 patients, the urinary samples were voided urine (UV), while, in 380 cases, the samples were collected after bladder washing (IU). For all the patients with invalid BE results, a second BE test was performed following the instructions for use that indicated the test should be repeated with a new urinary sample in the case of an invalid result. RESULTS: Analyzing the two different groups (UV and IU), we found the invalid BE results seemed to be not related to urinary samples (p = 0.13 Fisher's exact test), suggesting that the collection method was not relevant in order to reduce the number of invalid tests. CONCLUSIONS: In the follow-up for NMIBC, for patients for whom a BE test is planned, a combined approach of cytology and a methylation test is recommended in order to repeat the BE test with an invalid result only in those cases with a cytological diagnosis of atypical urothelial cells (AUC) suspicious for high-grade urothelial carcinoma (SHGUC) and high-grade urothelial carcinoma (HGUC).

Sterol, tocopherol, and bioactive fatty acid differences between conventional, high-quality, and organic cow milk.

Milk contains several components that are important for human nutrition and health. To date, studies on organic and conventional milk have focused on their gross composition and fatty acid content, but little attention has been paid to the differences between other minor components, such as sterols and vitamins that may have functional actions. The aim of this study was to investigate the nutritional differences among 3 types of milk from a dairy plant: conventional, high-quality, and organic (in compliance with European regulations) milk, focusing on minor components such as sterols of animal and plant origin (phytosterols), tocopherols, and bioactive fatty acids. Cholesterol ranged from 271.37 mg/100 g of fat in conventional milk to 278.76 mg/100 g of fat in organic milk. Lanosterol was the main minor animal sterol in cow milk (ranging from 3.41 to 4.37 mg/100 g of fat), followed by desmosterol. The amount of total plant sterols in the analyzed milk ranged from 4.43 mg/100 g of fat in organic to 4.71 mg/100 g of fat in high-quality milk. Brassicasterol was the main sterol of plant origin which varied from 2.6 mg/100 g of fat in conventional and organic milk, to 2.93 mg/100 g of fat in high-quality milk. The second most present phytosterol was ß-sitosterol, which ranged from 0.86 mg/100 g of fat in conventional to 0.97 mg/100 g of fat in high-quality, and organic milk. The results of the study showed no significant differences in gross and sterol composition between the 3 types of milk. However, the only significant difference found was in the fatty acid profile, with a higher n-3 content found in high-quality milk than in conventional and organic milk. These findings suggest that the investigated product categories and labels have minimal effect on the sterol and fatty acid profile of commercial cow milk.

Severe asthma: follow-up after one year from the Italian Registry on Severe Asthma (IRSA)

Summary: Background. Asthma affects millions of people worldwide, with a subgroup suffering from severe asthma (SA). Biologics have revolutionized SA treatment, but challenges remain in managing different patient traits. This study analyzed data from the Italian Registry on Severe Asthma (IRSA) to investigate changes in SA characteristics and effectiveness of treatments after one year of follow-up, and to identify factors associated with response to treatments in a real-world setting. Methods. Data on SA patients with one year of follow-up were extracted from IRSA. Asthma control, exacerbations, lung function, and treatments, were assessed at follow-up and analyzed against baseline characteristics. Results. After one year of follow-up, notable improvements were observed in all the outcomes of SA of the included patients (n = 570). The effectiveness of biologic therapies was particularly evident, as they contributed significantly to these positive outcomes. Additionally, certain factors were found to be associated with improvement, namely T2 phenotype, baseline eosinophil count (BEC), and area of residence. On the other hand, comorbidities (obesity, gastro-esophageal reflux disease) and poor lung function were risk factors. Notably, poor-responders to biologics exhibited lower level of education, BEC, and exacerbations, and higher frequency of atopy and ACT score ≥ 20. Conclusions. The findings demonstrate the effectiveness of biologics in asthma management, when implemented as part of a planned follow-up strategy aimed at optimizing and fine-tuning the therapy. Moreover, the study highlights the importance of considering key traits such as the T2 phenotype, BEC, education, and comorbidities when tailoring SA treatment. Overall, this study contributes to enhancing our understanding of SA management and guiding the development of personalized treatment approaches for patients with SA.

Investigating the Impact of the Glycolipid Content on Aurein 1.2 Pores in Prokaryotic Model Bilayers: A Coarse-Grain Molecular Dynamics Simulation Study.

Aurein 1.2 is an antimicrobial peptide (AMP) with known lytic activity against bacterial membranes. Our previous studies revealed a differential action of aurein by both experimental and computational methods. This differential action was over membranes of two related probiotic strains, where the main difference between membranes was the number of glycolipids in the lipid composition. In this work, we aimed to investigate the interaction of aurein 1.2 with model bacterial membranes of varying glycolipid content. To this end, we performed extensive molecular dynamics simulations using the MARTINI coarse-grain force field and differential mixtures of phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and monogalactosylglycerol (MG). We found a correlation between the presence of MG in PG/PE mixtures and the difficulty of aurein to stabilize pore structures, suggesting an AMP-resistance factor encoded in the lipid composition of the membrane. These findings may shed light on a possible mechanism of bacterial resistance to AMPs that is related to the glycolipid content of bacterial membranes.

Biophysical Analysis to Assess the Interaction of CRAC and CARC Motif Peptides of Alpha Hemolysin of Escherichia coli with Membranes.

Alpha hemolysin of Escherichia coli (HlyA) is a pore-forming protein, which is a prototype of the "Repeat in Toxins" (RTX) family. It was demonstrated that HlyA-cholesterol interaction facilitates the insertion of the toxin into membranes. Putative cholesterol-binding sites, called cholesterol recognition/amino acid consensus (CRAC), and CARC (analogous to CRAC but with the opposite orientation) were identified in the HlyA sequence. In this context, two peptides were synthesized, one derived from a CARC site from the insertion domain of the toxin (residues 341-353) (PEP 1) and the other one from a CRAC site from the domain between the acylated lysines (residues 639-644) (PEP 2), to study their role in the interaction of HlyA with membranes. The interaction of peptides with membranes of different lipid compositions (pure POPC and POPC/Cho of 4:1 and 2:1 molar ratios) was analyzed by surface plasmon resonance and molecular dynamics simulations. Results demonstrate that both peptides interact preferentially with Cho-containing membranes, although PEP 2 presents a lower KD than PEP 1. Molecular dynamics simulation results indicate that the insertion and interaction of PEP 2 with Cho-containing membranes are more prominent than those caused by PEP 1. The hemolytic activity of HlyA in the presence of peptides indicates that PEP 2 was the only one that inhibits HlyA activity, interfering in the binding between the toxin and cholesterol.

Design, synthesis and biological evaluation of novel thiosemicarbazones as cruzipain inhibitors.

Based on the activity of 23 TSCs on CZ taken from the literature, we have developed a QSAR model for predicting the activity of TSCs. New TSCs were designed and then tested against CZP, resulting in inhibitors with IC50 values in the nanomolar range. The modelling of the corresponding TSC-CZ complexes by molecular docking and QM/QM ONIOM refinement indicates a binding mode compatible with what was expected for active TSCs, according to a geometry-based theoretical model previously developed by our research group. Kinetic experiments on CZP suggest that the new TSCs act by a mechanism that involves the formation of a reversible covalent adduct with slow association and dissociation kinetics. These results demonstrate the strong inhibitory effect of the new TSCs and the benefit of the combined use of QSAR and molecular modelling techniques in the design of new and potent CZ/CZP inhibitors.

Solid phase extraction with rotating cigarette filter for determination of bisphenol A in source and drinking water: computational and analytical studies.

An ultrasound assisted solid phase extraction method using rotating cigarette filter is developed herein to preconcentrate and determine trace amount of bisphenol in source and drinking water. Qualitative and quantitative measurements were performed using high-performance liquid chromatography coupled with ultra violet detector. Sorbent-analyte interactions were thoroughly investigated computationally and experimentally using molecular dynamics simulations; and attenuated total reflectance Fourier transform infrared spectroscopy, and Raman spectroscopy, respectively. Various extraction parameters were investigated and optimized. Under the optimal conditions, the results were linear in a low scale range of 0.01-55 ng/mL with correlation coefficient of 0.9941 and a low limit of detection (0.04 ng/mL, signal/noise = 3:1). A good precision (intra-day relative standard deviation ≤ 6.05%, inter-day relative standard deviation ≤ 7.12%) and recovery (intra-day ≥ 98.41%, inter-day ≥ 98.04%)) are obtained. Finally, the proposed solid phase extraction method offered a low cost, simple, fast, and sensitive analytical method to determine trace amount of bisphenol A in source and drinking water samples with chromatographic detection.

Molecular study of endo and phytocannabinoids on lipid membranes of different composition.

The discovery of the endocannabinoid system (ECS) dates back only 30 years. Although many research groups have been elucidating its components, location, functions and metabolism, the peculiarities of the compounds considered "neurotransmitters" of ECS generate questions that have not yet been answered or controversies in the literature. In this context, we studied the molecular behaviour of the main endocannabinoid compounds and the main phytocannabinoids in eukaryotic outer and inner model membranes. The high lipophilicity of these compounds gives place to the hypothesis that cannabinoids may reach the molecular targets through the lipid bilayer. This consideration is not only for the cannabinoid receptors but also for other (many) targets that these bioactive molecules modulate (Watkins, 2019; Nelson et al., 2020; Jakowiecki and Filipek, 2016). Given the reported multitarget action of these compounds and the differential behaviour towards the different receptors, studying the properties and dynamics of these cannabinoids in POPC and POPE model membranes become relevant. In this regard, we have studied the differential modulation of the endocannabinoids anandamide and 2-arachidonoyl-glycerol and the phytocannabinoids cannabidiol and trans-Δ9-tetrahydrocannabinol to eukaryotic outer and inner model membranes. Results show that behaviours favour the mobility of the bioactive molecules studied by the external eukaryotic model membrane. As well as, the internal eukaryotic model membrane is less fluid, favouring the stabilisation of folded conformations or the positioning of the molecules in the centre of the bilayer. These results provide relevant evidence that contributes to a deep inside understanding of the behaviour of the primary endogenous ligands of ECS, together with the principal phytocannabinoids of C. sativa.

Aristotle - Ἀριστοτέλης (ARISTOTÉLES, 384/3- 322/1 BCE) The revelation of tuberculosis in his zoological works.

One of the most challenging issues with the sources of ancient medicine is to be able to identify the correspondence between the diseases we know today and those reported in ancient medical texts. Ancient diseases' definitions rarely help us, and the symptoms described often correspond to more than one disease. This is especially true about tuberculosis, a disease that historians of medicine habitually associates with the Greek words phthi(n)o (φθίνω), verb, phthisis/phthoe (φθίσις/φθόη), noun, phthinodes/phthisikos (φθινώδης/φθισικός), adjective, all etymologically linked to an Indo-European root that expresses the idea of consumption in a broad sense. This article aims to analyze a group of Greek words, branchos/branchia (ßράγχος/ßράγχια), krauros/kraurao (κραῦρος/κραυράω), and katarreo (καταρρέω), that appear in nosological contexts very close to the infectious disease that today we call tuberculosis. Moreover, the paper aims to focus on the transmission pathways of TB being via animal-human contact and some ancient strategies to cure it. The symptoms, transmission pathways and therapeutic approach of tuberculosis belong to a homogeneous pathological picture that emerges from a set of texts that date back to the period between the fifth century BC and the second century AD.

Protective effect of the tunneling nanotube-TNFAIP2/M-sec system on podocyte autophagy in diabetic nephropathy.

Podocyte injury leading to albuminuria is a characteristic feature of diabetic nephropathy (DN). Hyperglycemia and advanced glycation end products (AGEs) are major determinants of DN. However, the underlying mechanisms of podocyte injury remain poorly understood. The cytosolic protein TNFAIP2/M-Sec is required for tunneling nanotubes (TNTs) formation, which are membrane channels that transiently connect cells, allowing organelle transfer. Podocytes express TNFAIP2 and form TNTs, but the potential relevance of the TNFAIP2-TNT system in DN is unknown. We studied TNFAIP2 expression in both human and experimental DN and the renal effect of tnfaip2 deletion in streptozotocin-induced DN. Moreover, we explored the role of the TNFAIP2-TNT system in podocytes exposed to diabetes-related insults. TNFAIP2 was overexpressed by podocytes in both human and experimental DN and exposre of podocytes to high glucose and AGEs induced the TNFAIP2-TNT system. In diabetic mice, tnfaip2 deletion exacerbated albuminuria, renal function loss, podocyte injury, and mesangial expansion. Moreover, blockade of the autophagic flux due to lysosomal dysfunction was observed in diabetes-injured podocytes both in vitro and in vivo and exacerbated by tnfaip2 deletion. TNTs allowed autophagosome and lysosome exchange between podocytes, thereby ameliorating AGE-induced lysosomal dysfunction and apoptosis. This protective effect was abolished by tnfaip2 deletion, TNT inhibition, and donor cell lysosome damage. By contrast, Tnfaip2 overexpression enhanced TNT-mediated transfer and prevented AGE-induced autophagy and lysosome dysfunction and apoptosis. In conclusion, TNFAIP2 plays an important protective role in podocytes in the context of DN by allowing TNT-mediated autophagosome and lysosome exchange and may represent a novel druggable target.Abbreviations: AGEs: advanced glycation end products; AKT1: AKT serine/threonine kinase 1; AO: acridine orange; ALs: autolysosomes; APs: autophagosomes; BM: bone marrow; BSA: bovine serum albumin; CTSD: cathepsin D; DIC: differential interference contrast; DN: diabetic nephropathy; FSGS: focal segmental glomerulosclerosis; HG: high glucose; KO: knockout; LAMP1: lysosomal-associated membrane protein 1; LMP: lysosomal membrane permeabilization; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; PI3K: phosphoinositide 3-kinase; STZ: streptozotocin; TNF: tumor necrosis factor; TNFAIP2: tumor necrosis factor, alpha-induced protein 2; TNTs: tunneling nanotubes; WT: wild type.

COVID-19 lockdown, personal protective equipment, hyper-hygiene and allergy.

Summary: At the beginning of SARS-CoV 2 pandemic, in the absence of "targeted" therapies, the national health authorities have introduced some measures aimed at reducing the spread of infection in the community (lockdown, social distancing, personal protective equipment (PPE), personal hygiene and disinfection of living environments). All the containment measures have led to both positive and negative effects in patients with allergic diseases. We believe that further studies should be undertaken to investigate the possible correlations between SARS-CoV-2 infection and allergy, from a broader perspective. In particular, the risk factors for the development of undesirable effects should be investigated, especially in healthcare professionals forced to use PPE and sanitizing agents for a long time. However, since the COVID-19 pandemic probably will not be short-lived, the use of such protective aids will necessarily be widespread even in the general population. Therefore, further studies on the materials used for the production of PPE and sanitizing agents would be necessary to reduce their sensitizing and, in some cases, toxic potential.

Smallpox vaccination and vaccine hesitancy in the Kingdom of the Two Sicilies (1801) and the great modernity of Ferdinand IV of Bourbon: a glimpse of the past in the era of the SARS-COV-2 (COVID-19) pandemic.

OBJECTIVE: The current health emergency caused by COVID-19 disease shows several correspondences with well-known epidemics of the past. The knowledge of their management and overcoming could give us useful tools to face the present COVID-19 pandemic and future epidemics. STUDY DESIGN: On 1 March 1801, the first smallpox vaccinations were carried out in Palermo, and a few weeks later, the vaccine was also administered in Naples and the various provinces of the Kingdom. We aim to study the mass vaccination programme initiated by the Bourbon king Ferdinand IV that was the first large-scale campaign to be conducted in Italy and one of the first in Europe. METHODS: The authors searched and examined historical testimony and different aspects linked to the public health issues on vaccination. It is a topical topic in the current period with the COVID pandemic. RESULTS: Albeit with the due differences determined by the passage of time and by the scientific and cultural advances of modern society, this testimony from the past can provide us with food for thought regarding how to face the present COVID-19 pandemic and to prepare for the future. Indeed, it shows us how the terrible smallpox epidemic was handled and finally overcome, thanks to vaccination.

Revisión sistemática y metaanálisis sobre CK20, CD44, Ki67 y p53 como marcadores inmunohistoquímicos en el carcinoma in situ vesical / A systematic review and meta-analysis of CK20, CD44, Ki67 and p53 as immunohistochemical markers in bladder carcinoma in situ

Introducción: La displasia urotelial y el carcinoma in situ (CIS) están relacionados con la recurrencia y la progresión del carcinoma urotelial. Diferenciar el CIS y la displasia de la atipia reactiva suele ser difícil sobre la base de las características histológicas. La integración de los hallazgos histológicos con la inmunohistoquímica se utiliza en la práctica habitual para realizar el diagnóstico del CIS y, para ello, se utilizan los marcadores inmunohistoquímicos CK20, CD44, Ki67 y p53 como complemento al estudio histológico.En este trabajo, nos propusimos evaluar CK20, CD44, Ki67 y p53 como marcadores inmunohistoquímicos en pacientes con CIS, mediante una revisión sistemática y un metaanálisis.Materiales y métodosSe realizó una revisión sistemática con búsqueda en bases de datos electrónicas de estudios en inglés publicados desde enero de 2010 hasta abril de 2021. Se consideraron elegibles los estudios que evaluaban la expresión de CK20, CD44, Ki67 y p53 en el CIS.ResultadosEn total, 15 referencias fueron aptas para la revisión cuantitativa. La tasa global de expresión de CK20, CD44, Ki67 y p53 en el CIS fue del 43%, 31%, 44% y 38%, respectivamente.ConclusionesNuestro estudio apoya el consenso de la Sociedad Internacional de Patología Urológica de 2014 sobre la evaluación histológica como método de referencia para diagnosticar el CIS urotelial, y sugiere que una correlación muy estrecha entre los datos morfológicos, inmunohistoquímicos y clínicos es esencial para proporcionar el mejor manejo de los pacientes con carcinoma vesical. (AU)

Introduction: Urothelial dysplasia and carcinoma in situ (CIS) are related to recurrence and progression of urothelial carcinoma. Differentiating CIS and dysplasia from reactive atypia is often difficult based only on histological features. The integration of histological findings with immunohistochemistry is used in routine practice to make a diagnosis of CIS and, for this purpose, the immunohistochemical markers CK20, CD44, Ki67 and p53 are used to supplement histology.In this work, we aimed to assess CK20, CD44, Ki67 and p53 as immunohistochemical markers in patients with CIS through a systematic review and meta-analysis.Materials and methodsA systematic review was performed by searching electronic databases for English-language studies published from January 2010 to April 2021. Studies were considered eligible if they evaluated the CK20, CD44, Ki67 and p53 expression in CIS.ResultsIn total, 15 references were suitable for quantitative review. The overall rate of CK20, CD44, Ki67 and p53 expression in CIS was 43%, 31%, 44%, 38%, respectively.ConclusionsOur study supports the 2014 International Society of Urologic Pathology consensus that histological assessment remains the gold standard to diagnose urothelial CIS and suggests that a very close correlation between morphological, immunohistochemical and clinical data is essential to provide the best management for patients with bladder carcinoma. (AU)

A systematic review and meta-analysis of CK20, CD44, Ki67 and p53 as immunohistochemical markers in bladder carcinoma in situ.

BACKGROUND: Urothelial dysplasia and carcinoma in situ (CIS) are related to recurrence and progression of urothelial carcinoma. Differentiating CIS and dysplasia from reactive atypia is often difficult based only on histological features. The integration of histological findings with immunohistochemistry is used in routine practice to make a diagnosis of CIS and, for this purpose, the immunohistochemical markers CK20, CD44, Ki67 and p53 are used to supplement histology. In this work, we aimed to assess CK20, CD44, Ki67 and p53 as immunohistochemical markers in patients with CIS through a systematic review and meta-analysis. MATERIALS AND METHODS: A systematic review was performed by searching electronic databases for English-language studies published from January 2010 to April 2021. Studies were considered eligible if they evaluated the CK20, CD44, Ki67 and p53 expression in CIS. RESULTS: In total, 15 references were suitable for quantitative review. The overall rate of CK20, CD44, Ki67 and p53 expression in CIS was 43%, 31%, 44%, 38%, respectively. CONCLUSIONS: Our study supports the 2014 International Society of Urologic Pathology consensus that histological assessment remains the gold standard to diagnose urothelial CIS and suggests that a very close correlation between morphological, immunohistochemical and clinical data is essential to provide the best management for patients with bladder carcinoma.

From triggers to asthma: a narrative review on epithelium dysfunction.

Summary: It is currently recognized that the airway epithelium plays a pivotal role in orchestrating inflammatory, immune, and regenerative responses to allergens, viruses and environmental pollutants that contribute to asthma pathogenesis. The impact of pollen on respiratory epithelium is multifaceted and goes beyond the direct barrier damage driven by the best-known Type-2 response. After pollen-driven activation, airway epithelial cells play an active role in triggering several pathways. In particular, the release of epithelial cytokines (or alarmins) activates both innate and adaptive immunity, with downstream effects implicated to the pathogenesis of asthma. Pollutants also have a pleiotropic effect on respiratory epithelium. Diesel exhaust particles can directly damage the respiratory epithelium with consequent barrier dysfunction, increased permeability, and local inflammation, but they can also activate Th2 responses. Innate immune responses also are triggered by pollutants through release of epithelial cytokines and redox-sensitive pathways that generate mechanical and immunologic changes in the respiratory epithelium. In addition to the typical Type-1 immune response, respiratory virus infections stimulate type-2 innate lymphoid cells in the airway epithelium to release epithelial cytokines. Finally, the action of epithelial triggers on airway smooth muscle is the central element in the induction of remodeling and hyperreactivity of the airways in asthma. This article reviews the pathophysiology and functions of the airway epithelium and the role of epithelial damage by different triggers in the development, persistence, and exacerbations of asthma.