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Background: Airway epithelial injury is a crucial component of acute and severe asthma pathogenesis and a promising target for treatment of refractory asthma. However, the underlying mechanism of epithelial injury remains poorly explored. Although high levels of polyamines, mainly spermine, have been found in asthma and comorbidity, their role in airway epithelial injury and the cause of their altered levels in asthma have not been explored., Methods: We measured key polyamine metabolic enzymes in lung samples from normal and asthmatic subjects and in mice with OVA-induced allergic airway inflammation (AAI). Polyamine metabolism was modulated using pharmacologic/genetic modulators. Epithelial stress and apoptosis were measured by TSLP levels and TUNEL assay, respectively., Results: We found loss of the polyamine catabolic enzymes spermidine/spermine-N (1)-acetyltransferase-1 (SAT1) and spermine oxidase (SMOX) predominantly in bronchial epithelial cells (BECs) of human asthmatic lung samples and mice with AAI. In naïve mice, SAT1 or SMOX knockdown led to airway hyper-responsiveness, remodeling, and BEC apoptosis. Conversely, in mice with AAI, overexpression of either SAT1 or SMOX alleviated asthmatic features and reduced TSLP levels and BEC apoptosis. Similarly, while pharmacological induction of SAT1 and SMOX using the polyamine analogue bis(ethyl)norspermine (BENSPM) alleviated asthmatic features with reduced TSLP levels and BEC apoptosis, pharmacological inhibition of these enzymes using BERENIL or MDL72527, respectively, worsened them. Spermine accumulation in lungs correlated with BEC apoptosis, and spermine treatment caused apoptosis of human BEAS-2B cells in vitro., Conclusions: Spermine induces BEC injury. Induction of polyamine catabolism may represent a novel therapeutic approach for asthma via reversing BEC stress., (© 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Objectives/hypothesis: The vocal fold epithelium that includes tight junction (TJ)-based barrier function protects underlying connective tissues from external insults. TJs play an important role to control paracellular permeability of not only solutes but also ions, and preserve the vocal fold homeostasis. However, the distribution of TJs and paracellular diffusion barrier across the entire vocal fold epithelium are still unknown. The aim of this study was to identify the distribution of TJs in the vocal fold epithelium and to characterize the recovery process of TJ-based paracellular diffusion barrier in a rat model of vocal fold injury., Study Design: Animal experiments with controls., Methods: Normal and vocal fold-injured rats were used. Larynges were harvested for immunohistochemical examination of TJ proteins. For functional analysis, a tracer permeability assay was performed using EZ-Link Sulfo-NHS-LC-Biotin., Results: TJ proteins occludin and zonula occludens 1 signals were localized to the junctional regions of the most luminal cell layers of the vocal fold epithelium. The injured region had been recovered with epithelium at 5 days postinjury, but the paracellular diffusion barrier assays revealed that biotinylation reagents diffused into the lamina propria at 5 days postinjury, and were blocked at the epithelium at 14 and 28 days postinjury., Conclusions: It was strongly suggested that TJs in the vocal fold epithelium exist at the junctional regions of the first layer of stratified squamous epithelium. TJ-based paracellular diffusion barrier following vocal fold injury is recovered by 14 days postinjury, and this period corresponds with the time course of structural changes in the regenerating epithelium layer., Level of Evidence: NA. Laryngoscope, 128:E150-E156, 2018., (© 2017 The American Laryngological, Rhinological and Otological Society, Inc.)

Keratinocyte growth factor (KGF) is a paracrine-acting epithelial mitogen produced by cells of mesenchymal origin, that plays an important role in protecting and repairing epithelial tissues. Pre-clinical data initially demonstrated that a recombinant truncated KGF (palifermin) could reduce gastrointestinal injury and mortality resulting from a variety of toxic exposures. Furthermore, the use of palifermin in patients with hematological malignancies reduced the incidence and duration of severe oral mucositis experienced after intensive chemoradiotherapy. Based upon these findings, as well as the observation that KGF receptors are expressed in many, if not all, epithelial tissues, pre-clinical studies have been conducted to determine the efficacy of palifermin in protecting different epithelial tissues from toxic injury in an attempt to model various clinical situations in which it might prove to be of benefit in limiting tissue damage. In this article, we review these studies to provide the pre-clinical background for clinical trials that are described in the accompanying article and the rationale for additional clinical applications of palifermin., (© 2013 The Authors. Journal of Cellular and Molecular Medicine Published by Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.)

Objectives: This study was designed to test the efficacy in plaque removal and the potential for gingival abrasion of 3 electric toothbrushes. The established Braun Oral-B 'Ultra' plaque remover (D9), the Philips/Jordan HP 735, and the newly designed Braun Oral-B 3D Plaque Remover (3D)., Material and Methods: This study was designed as a split-mouth, single blind, randomised clinical study consisting of 3 identical experiments with 3 combinations of toothbrushes (exp 1:3D-HP735, exp 2:D9-HP735, exp 3:D9-3D). 40 subjects were requested not to brush their teeth 48 h prior to each examination. At this visit, both the gums and teeth were disclosed for the assessment of baseline plaque and gingival abrasion. Abrasion sites were scored as small (< or = 5 mm) or large sites (> 5 mm). Plaque was assessed according to the Quigley & Hein index at 6 sites per tooth. The participants brushed 60 s with the 2 brushes, each brush in 2 randomly selected contra-lateral quadrants., Results: The increase in number of small abrasions after brushing (exp. 1) was 1.2 versus 1.7 for 3D and HP735, respectively (ns); In exp. 2 the increase was 0.9 for both D9 and HP735. In exp. 3 the increase was 0.4 sites for both D9 and 3D. Comparison of the 3D and HP735 showed a mean plaque reduction of 67% and 54%, respectively (p<0.05); when the D9 and HP735 were compared, a mean plaque reduction of 70% and 58%, respectively, was found (p<0.05); a mean plaque reduction of 74% was found in the comparison of D9 and 3D., Conclusion: The results show that the potential gingival abrasion after brushing is comparable for all 3 electric toothbrushes. In addition the longer the subjects used the brushes the less abrasion occurred. Finally both 3D and D9 were more effective than the HP735 in removing plaque.

Platelet-derived growth factor (PDGF) is a polypeptide growth factor which has been implicated as a major mitogen involved in wound healing. The PDGF appears to promote periodontal regeneration; however, its distribution in gingival tissues is not known and how it participates in gingival wound healing is unclear. Using highly specific antibodies we have studied the distribution of PDGF A and B chains and alpha- and beta-PDGF receptors in healing human gingival wounds. Wounds were created by making a 0.75 mm deep incision in the papilla and healthy gingiva and biopsies were obtained from the same site after 8 h and 1, 3, 7, 14 and 21 d. Frozen sections were immunostained with affinity purified antibodies. The results showed that both epithelium and fibrin clot manifested positive immunostaining for anti-PDGF-A and B-chain antibodies. Staining was present in unwounded and wounded epithelia, and in the fibrin clot it appeared to be more intense for the PDGF-A chain. Blood vessels in connective tissue were also positive while other areas were largely negative. No significant staining was detectable in healthy tissues for anti-PDGF-alpha or -beta receptor antibodies. However, the wound site began to manifest positive immunostaining fro anti-beta-receptor antibody after 3 d of healing, became maximal at 7 d, and then decreased. Our data indicate, but do not prove, that gingival epithelium may be a source of PDGF A and B chains and that the A chain may have a more prominent role to play during early stages of healing. Expression of PDGF beta-receptor appears later at the wound site, indicating that the PDGF B isomer may regulate later wound healing events.

Tenascin is a large oligomeric glycoprotein of the extracellular matrix that is expressed prominently during embryonic development and wound healing. Previous studies on tenascin expression in wounds have used immunohistochemistry to describe the expression of tenascin in wounds. The present study used in situ hybridization to identify the cells expressing tenascin mRNA in healing wounds. The results demonstrate that the cells of the basal layer of epidermis, migrating over the healing wound, are expressing the mRNA for tenascin. Intense expression was seen during the first three days after wounding, but after seven days, after the epithelium had grown to cover the wound, no tenascin transcripts were seen in epithelial cells. The epithelial cells elsewhere in the skin were devoid of tenascin transcripts at all stages examined. Previously, prominent immunohistological staining for tenascin has been located in wounds below the migrating epithelial cells and it has been thought to be synthesized by stromal cells upon epithelial induction. Our findings in the present study indicate that tenascin is produced by epithelial cells, which apparently are induced to produce tenascin as they migrate after wounding.

A method of assessing the damaging effects of non-surgical instrumentation was developed. To test the technique, the effect of cavitational activity in the water supply of an ultrasonic scaler was investigated in an in vivo situation. Using a replication technique for the scanning electron microscope, it was shown that the water supply of the ultrasonic scaler caused superficial disruption of the surface of the gingiva, distant from the area of damage caused by mechanical contact. The results indicated that further investigations of this phenomenon using the technique were required.