Tracheal Glands Research Articles

Versatility of the supraclavicular artery island flap for head and neck reconstruction.

To present our experience using the supraclavicular artery island flap (SCAIF) for head and neck reconstruction. We performed a retrospective chart review to identify patients who underwent head and neck reconstruction with SCAIF at our institution. The following data were collected: age, sex, surgical indications, flap harvest time, flap dimensions, length of hospital stay, complications, and clinical outcomes. Thirty-three patients underwent SCAIF reconstruction, of whom four underwent pectoralis major myocutaneous flap reconstruction simultaneously. Twenty flaps were used to repair pharyngeal or esophageal defects following resection for tonsillar, hypopharyngeal, laryngeal, and cervical esophageal cancers. Five flaps were used for tracheal reconstruction following resection for tracheal or thyroid gland cancer. Seven flaps were used for reconstruction of cervical skin defects or fistulas related to a previous treatment. One flap for tracheal stenosis following tracheotomy. The mean age of the patients was 60.69 ± 11.47 years. The mean flap harvest time was 32.00 ± 4.44 min. The mean flap size was 10.16 ± 3.91 × 5.78 ± 0.68 cm. The mean length of hospital stay is 24.84 ± 13.78 days. Three patients had partial necrosis of the distal portion of the flap, which resolved with anti-infection therapy and local wound care. One patient developed a fistula that was resolved with wound care and further surgical intervention. Complete flap loss or major complications were not observed. No donor site complication or compromised shoulder function was observed. The SCAIF can be successfully used to reconstruct head and neck defects with good outcomes and limited morbidity. 4.

A Missense Mutation in the Collagen Triple Helix of EDA Is Associated with X-Linked Recessive Hypohidrotic Ectodermal Dysplasia in Fleckvieh Cattle.

Mutations within the ectodysplasin A (EDA) gene have been associated with congenital hypotrichosis and anodontia (HAD/XHED) in humans, mice, dogs and cattle. We identified a three-generation family of Fleckvieh cattle with male calves exhibiting clinical and histopathological signs consistent with an X-linked recessive HAD (XHED). Whole genome and Sanger sequencing of cDNA showed a perfect association of the missense mutation g.85716041G>A (ss2019497443, rs1114816375) within the EDA gene with all three cases following an X-linked recessive inheritance, but normal EDAR and EDARADD. This mutation causes an exchange of glycine (G) with arginine (R) at amino acid position 227 (p.227G>R) in the second collagen triple helix repeat domain of EDA. The EDA variant was associated with a significant reduction and underdevelopment of hair follicles along with a reduced outgrowth of hairs, a complete loss of seromucous nasolabial and mucous tracheal and bronchial glands and a malformation of and reduction in number of teeth. Thermostability of EDA G227R was reduced, consistent with a relatively mild hair and tooth phenotype. However, incisors and canines were more severely affected in one of the calves, which correlated with the presence of a homozygous missense mutation of RNF111 (g.51306765T>G), a putative candidate gene possibly associated with tooth number in EDA-deficient Fleckvieh calves.

The internal anatomy of the scale mite Pterygosoma pseudotrapelus (Trombidiformes, Pterygosomatidae)

This study is the first description of the internal anatomy of the scale mites using the example of parasitizing Pterygosoma pseudotrapelus (Bochkov et al., 2009) – a parasite of agamid lizards. Data on histology of the integument, digestive tract, excretory organs, prosomal glands, tracheae, and body-cavity tissues of females, supplemented by the ultrastructure of major organs, are discussed in comparison with information from other groups of the Acari. The female reproductive system was examined only at the light microscopic level. The shape of mite body is adapted to the existence under the scales of the reptile, where the parasite spends its entire life. The width of the adult females is nearly twice their length, resulting in the eccentric position of certain internal organs: the large reproductive system is oriented across the body, so that the ovary with developing oocytes occupies the right side of the idiosoma, while oviduct, seminal receptacle, and vagina are displaced to the left. The structure of the tracheal system and the podocephalic complex of P. pseudotrapelus is similar to that of Tetranychoidea, a group also regarded as one of the lower taxa in the cohort Raphignathina. A number of previously unknown primitive traits identified in the study confirm a relatively basal position of the scale mites within Raphignathina. These include a panoistic ovary, the postcolon instead of an excretory organ of more advanced forms, and 2 pairs of podocephalic acinar glands against the general trend of their reduction in this cohort. An unpaired tracheal gland was found independent from the podocephalic system. The coxal glands lack a filtering sacculus and their epithelium forms mutual interdigitations with the surrounding modified ventricular wall.

Development of novel layered polyglycolic acid sheet for regeneration of critical-size defect in rat trachea.

Polyglycolic acid (PGA) sheets are difficult to adapt to the central airway because of poor durability against high air pressure. Therefore, we developed a novel layered PGA material to cover the central airway and examined its morphologic traits and functional performance as a potential tracheal replacement. A critical-size defect in rat cervical tracheas was covered with the material. Morphologic changes were bronchoscopically and pathologically evaluated. Functional performance was evaluated by regenerated ciliary area, ciliary beat frequency and ciliary transport function determined by measuring the moving distance of microspheres dropped onto the trachea (µm/s). The evaluation time points were 2 weeks, 1 month, 2 months and 6 months after surgery (n = 5, respectively). Forty rats underwent implantation, and all survived. Histological examination confirmed ciliated epithelization on the luminal surface after 2 weeks. Neovascularization was observed after 1 month, tracheal glands after 2 months and chondrocyte regeneration after 6 months. Although the material was gradually replaced by self-organization, tracheomalacia was not bronchoscopically observed at any time point. The area of regenerated cilia significantly increased between 2 weeks and 1 month (12.0% vs 30.0%; P = 0.0216). The median ciliary beat frequency significantly improved between 2 weeks and 6 months (7.12 vs 10.04 Hz; P = 0.0122). The median ciliary transport function was significantly improved between 2 weeks and 2 months (5.16 vs 13.49 µm/s; P = 0.0216). The novel PGA material showed excellent biocompatibility and tracheal regeneration both morphologically and functionally 6 months after tracheal implantation.

Detection of morphometrical, histological and histochemical characteristics of lung and trachea in adult local squirrel (Sciurus anomalus)

The present study aimed to identify the topography, morphology, histochemistry and histology of lung structures, bronchial divisions and trachea in adult local Squirrel (Sciurus anomalus) as a species inhabited in Iraqi environments. This work was conducted on thirty local Squirrel of both sexes (15) males and (15) females were divided into three equal groups, first for http://wsx5customurl.comanatomical perceptions, second to resin cast technique and the third for histological study. Anatomically, in both sexes, the trachea appeared as a cartilaginous structure consisting of flexible cartilaginous rings, C-like, connected by annular ligaments. It begins at the end of the cricoid cartilage from the level of the second cervical vertebra to the fourth thoracic vertebral plane; eventually, it splits into the right and left main bronchi. Count tracheal rings, the entire weight of the lung, full length, the diameter of the trachea and right and left bronchi. The trachea in females was slightly less than in males but not significantly. The bronchial tree was detected in resin cast, which was constructed of the trachea divided into left and right primary bronchi (Main bronchi), the right one was split into four secondary bronchi to enter the right lobes and two secondary bronchi to the left one. The left lung contains one lobe, whereas four lobes were observed in the right. Histologically, the wall of the trachea consists of four layers. Epithelial cells of ciliated pseudostratified columnar and goblet cells that reacted positively with PAS were covered in the mucosa. Submucosa was devoid of the tracheal glands. The Trachealis muscle is connected from the outer aspect of rings. Similarly to the trachea, the primary bronchi are structured but smaller in diameter; they break up within the lung into primary, secondary and tertiary bronchi, then it terminates in respiratory bronchioles that contain Clara cells and open at the end in the sacs of alveoli. Two types of pneumocystis were observed lining the alveoli. The current study concluded anatomically and histologically that there were no significant differences between males and females of local squirrels. The lobulation of the lung in squirrels is different from other animals. The trachea and lung histologically resembled numerous animals, however, the wall had micro morphometric changes. But, the surface lining cells of the tracheal and bronchi mucosa secrete neutral mucin, with no submucosal glands in the tracheal wall. Keywords: Trachea, Local Squirrel, Bronchial Tree, Histochemical, Lung.

Lipopolysaccharides induce a RAGE-mediated sensitization\xa0of sensory neurons and fluid hypersecretion in the upper airways

Thoracic dorsal root ganglia (tDRG) contribute to fluid secretion in the upper airways. Inflammation potentiates DRG responses, but the mechanisms remain under investigation. The receptor for advanced glycation end-products (RAGE) underlies potentiation of DRG responses in pain pathologies; however, its role in other sensory modalities is less understood. We hypothesize that RAGE contributes to electrophysiological and biochemical changes in tDRGs during inflammation. We used tDRGs and tracheas from wild types (WT), RAGE knock-out (RAGE-KO), and with the RAGE antagonist FPS-ZM1, and exposed them to lipopolysaccharides (LPS). We studied: capsaicin (CAP)-evoked currents and action potentials (AP), tracheal submucosal gland secretion, RAGE expression and downstream pathways. In WT neurons, LPS increased CAP-evoked currents and AP generation, and it caused submucosal gland hypersecretion in tracheas from WT mice exposed to LPS. In contrast, LPS had no effect on tDRG excitability or gland secretion in RAGE-KO mice or mice treated with FPS-ZM1. LPS upregulated full-length RAGE (encoded by Tv1-RAGE) and downregulated a soluble (sRAGE) splice variant (encoded by MmusRAGEv4) in tDRG neurons. These data suggest that sensitization of tDRG neurons contributes to hypersecretion in the upper airways during inflammation. And at least two RAGE variants may be involved in these effects of LPS.

Diversity and importance of tracheobronchial glands in mammalian species

This article focuses on tracheal submucosal glands and their role in health and disease. The occurrence, distribution and morphology of tracheobronchial glands differ among vertebrate – and even mammalian – species. Tracheal glands are of major importance in physiology but also in pathological conditions such as tracheobronchitis, acute and chronic lung injury, cystic fibrosis and others. Some species do not possess tracheal glands; tracheobronchial clearance is performed by other secretory units.

Imaging of Malignant Minor Salivary Gland Tumors of the Head and Neck.

Minor salivary gland carcinomas (MSGCs) are nonminor tumors in the head and neck region and account for about half of all salivary gland carcinomas. Imaging evaluation based on the anatomy of minor salivary and mucous glands in the head and neck region as well as invasion patterns in each site helps in identifying optimal treatment modalities and planning suitable treatment strategies. MSGCs can be divided radiologically into localized and invasive subtypes on the basis of the clinical utility of such categorization. Characteristic invasion patterns of the invasive type include deep submucosal extension, bone marrow infiltration, and perineural spread, which are difficult to assess clinically. MSGCs easily invade adjacent structures because of their submucosal location and may spread along the muscles, nerves, periosteum, and dura mater. Moreover, the tumor may spread into the bone marrow without obvious bone destruction. In addition to imaging classification, examining the anatomy and distribution of the minor salivary glands, including the palatal, lingual, buccal, labial, and retromolar glands, as well as other mucous glands, including the glands of the sinonasal cavity and nasopharynx, lacrimal glands, ceruminous glands, laryngeal glands, and tracheal glands, facilitates MSGC diagnosis and tumor extension assessment. The authors review the precise anatomy of the minor salivary and mucous glands in the head and neck region, discuss the MSGC imaging classifications, and describe how to evaluate the extent of MSGCs in each site on the basis of the imaging classification and invasion patterns. ©RSNA, 2020.

Acid exposure disrupts mucus secretion and impairs mucociliary transport in neonatal piglet airways.

Tenacious mucus produced by tracheal and bronchial submucosal glands is a defining feature of several airway diseases, including cystic fibrosis (CF). Airway acidification as a driving force of CF airway pathology has been controversial. Here we tested the hypothesis that transient airway acidification produces pathologic mucus and impairs mucociliary transport. We studied pigs challenged with intra-airway acid. Acid had a minimal effect on mucus properties under basal conditions. However, cholinergic stimulation in acid-challenged pigs revealed retention of mucin 5B (MUC5B) in the submucosal glands, decreased concentrations of MUC5B in the lung lavage fluid, and airway obstruction. To more closely mimic a CF-like environment, we also examined mucus secretion and transport following cholinergic stimulation under diminished bicarbonate and chloride transport conditions ex vivo. Under these conditions, airways from acid-challenged pigs displayed extensive mucus films and decreased mucociliary transport. Pretreatment with diminazene aceturate, a small molecule with ability to inhibit acid detection through blockade of the acid-sensing ion channel (ASIC) at the doses provided, did not prevent acid-induced pathologic mucus or transport defects but did mitigate airway obstruction. These findings suggest that transient airway acidification early in life has significant impacts on mucus secretion and transport properties. Furthermore, they highlight diminazene aceturate as an agent that might be beneficial in alleviating airway obstruction.

Morphology of trachea of mature chickens, grown under the conditions of radioactive contamination

The features of macro- and microscopic structure and morphometric parameters of the trachea of chickens of the Black Moscow breed of 180 days of age grown in conditionally pure and II zone of radioactive contamination are presented in the work using radiological, morphological, morphometric and statistical methods of research. It has been found that the presence of chickens in radioactively contaminated territories, feeding them with locally-sourced food, has an adverse effect on the respiratory organs, including the trachea. According to the results of radiological research, the increase of gamma background was established in the territory where the experimental part of the research was conducted. Thus, according to our observations, the specific power of the exposure dose of gamma rays for cesium-137 in the territory where the experimental animals were kept was almost in 3–3.5 times higher than this indicator for the relatively pure radioactive contamination of the territory. The specific activity of the diet for cesium-137 in chickens of 180 days of the experimental group was almost 8.5 times higher than in the control group of animals and was 13.4–16.0 Bq/kg, compared with the control (1.64–1.82 Bq/kg), indicating the cumulative capacity of this isotope. According to our research, the trachea of chickens of the experimental group has a pale pink color and is built of cartilage rings (110–120 units), which have a rounded shape. Its wall is formed by the mucous and fibrous cartilage and adventitia. The mucous membrane has a folded structure and is lined with multilayered ciliated epithelium and contains glands. Four types of cells are well differentiated into the epithelium: basal, ciliated, endocrine, and goblet. The fibrous cartilage sheath is formed by tracheal cartilages, which are interconnected by a dense fibrous connective tissue. The histoarchitectonics of the trachea of chickens reared in the second zone of radioactive contamination is similar to that of chickens in the control group. However, our morphometric studies noted that the animals of the experimental group increased the size of the terminal parts of the tracheal glands, thickened connective tissue capsules of the lymph nodes. The absolute body mass of the chickens of the experimental group, compared with the control group, tends to decrease and is respectively 2.96 ± 0.19 g, while the relative weight of the organ significantly (P ≤ 0.001) decreases to 0.284 ± 0.027%. In addition, for 180-day-old chickens that were constantly under radioactive contamination, the thickness of the mucous, fibrous, cartilage, and adventitious membranes tended to decrease compared to chickens from the conditionally clear area for radioactive contamination.

A novel rat model for tracheal mucosal damage assessment of following long term intubation

ObjectiveTracheal mucosal damage is a well-known complication of endo-tracheal intubation and animal models are essential for studying the underlying cellular injury cascade. The novel rat model described here is based on retrograde intubation via tracheotomy and suture fixation of the tube. It aims to simulate the common clinical scenario of tube-related airway damage due to long term intubation. Study designProspective randomized control pilot study. MethodsMale Sprague-Dawley were randomly assigned into two groups: control (no intubation, n = 10), one week of intubation (n = 13). The animals were then euthanized and the trachea was sent for histological analysis. Epithelial damage, mucosal thickness, mucosal gland hypertrophy and fibrosis were reviewed. ResultsIntubation procedure survival rate was 84.6% (11/13) and 100% in the control (10/10). The damaged ciliary mechanism was a common finding in the intubated group compared to the preserved normal ciliary architecture in almost all control rats. Average tracheal mucosal thickness was 119.0 ± 21.8 μm for the control group and 254.6 ± 22.8 μm for the intubated group, (p < 0.001). The ciliary damage score was 1.00 ± 0.02 in the intubated group, and 0 ± 0.02 in the control group. (p < 0.001). The (objective) average total tracheal mucosal gland area was 19,530 ± 24,606 in the intubated group and 10,031 ± 23,461 in the control group (p < 0,05). Collagen deposition seems higher in the intubated trachea compared to the control. ConclusionsWe describe a novel rat-based animal model for simulating tracheal mucosal damage following long term intubation. This animal model is easy to carry out, reproducible and involves containable animal mortality rates. Level of evidenceI.

FGF10 is an essential regulator of tracheal submucosal gland morphogenesis

Mucus secretion and mucociliary clearance are crucial processes required to maintain pulmonary homeostasis. In the trachea and nasal passages, mucus is secreted by submucosal glands (SMGs) that line the airway, with an additional contribution from goblet cells of the surface airway epithelium. The SMG mucus is rich in mucins and antimicrobial enzymes. Defective tracheal SMGs contribute to hyper-secretory respiratory diseases, such as cystic fibrosis, asthma, and chronic obstructive pulmonary disease, however little is known about the signals that regulate their morphogenesis and patterning. Here, we show that Fgf10 is essential for the normal development of murine tracheal SMGs, with gland development arresting at the early bud stage in the absence of FGF10 signalling. As Fgf10 knockout mice are lethal at birth, inducible knockdown of Fgf10 at late embryonic stages was used to follow postnatal gland formation, confirming the essential role of FGF10 in SMG development. In heterozygous Fgf10 mice the tracheal glands formed but with altered morphology and restricted distribution. The reduction in SMG branching in Fgf10 heterozygous mice was not rescued with time and resulted in a reduction in overall tracheal mucus secretion. Fgf10 is therefore a key signal in SMG development, influencing both the number of glands and extent of branching morphogenesis, and is likely, therefore, to play a role in aspects of SMG-dependent respiratory health.

La chirurgie des tumeurs primitives de la trachée de type glande salivaire

Primary tumours of the trachea are very rare and may develop from the tracheal salivary glands. We describe four patients operated on in our service between 2010 and 2017 of whom two had an adenocystic carcinoma, one a mucoepidermoid carcinoma and one a pleomorphic adenoma of the trachea. All were treated by resection and tracheal anastomosis with clear margins in three cases. The malignant cases received adjuvant treatment consisting of radiotherapy in one case and radiochemotherapy in the second. Immediate postoperative recovery was uncomplicated in all patients. One death followed the developement of post irradiation tracheal stenosis two years after surgery in a patient with an adenocystic carcinoma where the resection margins were invaded by tumour. Resection and anastomosis of the trachea remains the best therapeutic option with a better prognosis when the resection is complete.

TLR7 agonist attenuates acetylcholine-induced, Ca2+ -dependent ionic currents in swine tracheal submucosal gland cells.

What is the central question of this study? Does Toll-like receptor 7 (TLR7) have any direct effects on Ca2+ -dependent physiological function of tracheal submucosal gland cells? What is the main finding and its importance? TLR7 is co-localized with SERCA2 in tracheal submucosal gland cells and causes a rapid attenuation of acetylcholine (ACh)-induced, Ca2+ -dependent ionic currents through the activation of SERCA2-dependent Ca2+ clearance. TLR7 is abundantly expressed in the airways of both swine and healthy human subjects, but is significantly downregulated in chronic obstructive pulmonary disease (COPD) airways. These findings suggest that a dysfunction of TLR7 in COPD removes the brake on ACh-induced serous secretion during viral infections, resulting in prolonged airway hypersecretion, and that it is one of the triggers of COPD exacerbations. Airway surface fluids are mainly secreted from submucosal glands (SMGs) and play important roles in the defence of airways via the activation of mucociliary transport. Toll-like receptor 7 (TLR7) recognizes and eliminates single stranded RNA (ssRNA) viruses through the induction of innate immunity. However, there is no obvious connection between TLR7 and mucus secretion, aside from TLR7 recognizing ssRNA viruses, which are often associated with airway hypersecretion in chronic obstructive pulmonary disease (COPD). Here, we investigated whether TLR7 has any direct effects on the Ca2+ -dependent physiological function of tracheal SMG cells. Patch-clamp analyses revealed that TLR7 ligand inhibited the acetylcholine (ACh)-induced ionic currents in isolated tracheal SMG cells. Intracellular calcium assays and pharmacological analyses revealed that TLR7 attenuated the transient rises in the intracellular calcium concentration evoked by ACh by activating sarco/endoplasmic reticulum Ca2+ -ATPase 2 (SERCA2). Immunofluorescence staining and immunohistochemical staining revealed that TLR7 was co-localized with SERCA2. These findings suggest that the activation of TLR7 during viral infections contributes to the rapid attenuation of ACh-induced ionic currents through an increase in SERCA2-dependent Ca2+ clearance in healthy airway SMG cells. Our study also revealed that TLR7 expression was significantly downregulated in COPD airways. Based on these findings, we speculate that a dysfunction of TLR7 may not only have an adverse effect on the elimination of these viruses but also remove the brake on ACh-induced serous secretion, resulting in prolonged hypersecretion and acting as one of the triggers of COPD exacerbations.

A Comparative Histological Study of Submucosal Gland Hypertrophy in Trachea of Mice Exposed to Cigarette and Shisha Smoke.

To observe the effects of Shisha smoke on submucosal glands of trachea of mice; and compare it with tracheal glands of mice exposed to cigarette smoke. Randomised controlled trial. Department of Anatomy, Islamic International Medical College, Rawalpindi, in collaboration with National Institute of Health (NIH), Islamabad from October 2013 till April 2014. Sample comprised of 40 adult male mice of strain BALB/c. They were randomly divided into three groups. Control group was labelled as Group 'C'. The mice in this group were kept in a whole body smoke exposure chamber and were exposed to fresh air. Shisha group was labelled as Group 'SS', and the mice in this group were exposed to Shisha smoke. Mice in the third group labelled as Group CS were exposed to cigarette smoke. All the mice were dissected after an exposure period of eight weeks. Tracheal tissue was stained and examined microscopically for submucosal gland hypertrophy and compared with the control group, using Reid's Index. An Index of more than 0.4 is termed as hypertrophy. There was significant submucosal gland hypertrophy in groups CS and SS as compared to group C. There was also significant difference in the frequency of mucosal hypertrophy between SS (93.7%) and CS groups (53.3%), which was found statistically significant (p<0.001). Shisha smoking was significantly associated with mucosal hypertrophy when compared with cigarette smoking and controls. Shishasmoke contains higher level of toxicants as compared to cigarette smoke, and it causes more oxidative damage of tissues.

Immunohistochemical study on the distribution of β-defensin 1 and β-defensin 2 throughout the respiratory tract of healthy rats.

The distributions of β-defensin 1 and 2 in secretory host defense system throughout respiratory tract of healthy rats were immunohistochemically investigated. In the nasal epithelium, a large number of non-ciliated and non-microvillous cells (NCs) were immunopositive for both β-defensin 1 and 2, whereas a small number of goblet cells (GCs) were immunopositive only for β-defensin 1. Beta-defensin 2-immunopositive GCs were few. In the nasal glands, a small number of acinar cells and a large number of ductal epithelial cells were immunopositive for both β-defensins. In the laryngeal and tracheal epithelia, a very few NCs and GCs were immunopositive for both β-defensins. In laryngeal and tracheal glands, a very few acinar cells and a large number of ductal epithelial cells were immunopositive for both β-defensins. In the extra-pulmonary bronchus, a small number of NCs were immunopositive for both β-defensins. A small number of GCs were immunopositive for β-defensin 1, whereas few GCs were immunopositive for β-defensin 2. From the intra-pulmonary bronchus to alveoli, a very few or no epithelial cells were immunopositive for both β-defensins. In the mucus and periciliary layers, β-defensin 1 was detected from the nose to the extra-pulmonary bronchus, whereas β-defensin 2 was weakly detected only in the nose and the larynx. These findings suggest that the secretory sources of β-defensin 1 and 2 are mainly distributed in the nasal mucosa and gradually decrease toward the caudal airway in healthy rats.

Immunohistochemical study on the secretory host defense system with lysozyme and secretory phospholipase A2 throughout rat respiratory tract.

The host defense system with lysozyme and secretory phospholipase A2 (sPLA2) was immunohistochemically investigated in rat respiratory tract under healthy conditions. In the nasal epithelium, a large number of non-ciliated and non-microvillous cells (NC) and a small number of goblet cells (GC) were immunopositive for lysozyme and sPLA2. A few acinar cells and almost all epithelial cells of intercalated ducts were immunopositive for both bactericidal substances in the nasal glands. In the laryngeal and tracheal epithelia, few NC and GC were immunopositive for both bactericidal substances. In the laryngeal and tracheal glands, a few acinar cells and most ductal epithelial cells were immunopositive for both bactericidal substances. In extra-pulmonary bronchus, small numbers of NC and GC were immunopositive for lysozyme and sPLA2, whereas few NC and no GC were immunopositive in the intra-pulmonary bronchus. No secretory source of either bactericidal substance was located in the bronchioles. In the alveolus, many glandular epithelial cells and alveolar macrophages were immunopositive for lysozyme but immunonegative for sPLA2. Moreover, lysozyme and sPLA2 were detected in the mucus layer and in the periciliary layer from the nose to the extra-pulmonary bronchus. These findings suggest that secretory sources of lysozyme and sPLA2 are distributed in almost all the respiratory tract. Their secretory products are probably transported to the pharynx and contribute to form the first line of defense against inhaled bacteria throughout the respiratory tract.

Siglec-8 and Siglec-9 binding specificities and endogenous airway ligand distributions and properties.

Siglecs are transmembrane sialoglycan binding proteins, most of which are expressed on leukocyte subsets and have inhibitory motifs that translate cell surface ligation into immune suppression. In humans, Siglec-8 on eosinophils, mast cells and basophils and Siglec-9 on neutrophils, monocytes and some T-cells, mediate immune cell death, inhibition of immune mediator release and/or enhancement of anti-inflammatory mediator release. Endogenous sialoglycan ligands in tissues, mostly uncharacterized, engage siglecs on leukocytes to inhibit inflammation. Glycan array analyses demonstrated that Siglec-8, Siglec-9 and their mouse counterparts Siglec-F and Siglec-E (respectively) have distinct glycan binding specificities, with Siglec-8 more structurally restricted. Since siglecs are involved in lung inflammation, we studied Siglec-8 and Siglec-9 ligands in human lungs and airways. Siglec-8 ligands are in tracheal submucosal glands and cartilage but not airway epithelium or connective tissues, whereas Siglec-9 ligands are broadly distributed. Mouse airways do not have Siglec-8 ligands, whereas Siglec-9 ligands are on airways of both species. Extraction of human airways and lung followed by electrophoretic resolution and siglec blotting revealed Siglec-8 ligands in extracts of human trachea and cultured tracheal gland cells, but not parenchyma or cultured airway epithelial cells whereas Siglec-9 ligands were extracted from all airway and lung tissues and cells tested. Siglec-8 and Siglec-9 ligands in airways appear to be high molecular weight O-linked sialoglycoproteins. These data reveal differential glycan specificities of Siglec-8, Siglec-9 and their mouse counterparts Siglec-F and Siglec-E, and the tissue distributions and molecular characteristics of Siglec-8 and Siglec-9 sialoglycan ligands on human airways and lungs.

Histological Characteristics of the Tracheobronchial Tree of the Least Shrew (Cryptotis Parva).

The least shrew (Cryptotis parva) is a small vomit-competent insectivorous species which has recently been introduced as an emesis animal model in the laboratory. In this study, the respiratory system of the least shrew was examined and compared with the well-established larger species routinely used in the laboratory. Five least shrews (4-5g body weight, 45-60days old) were used. Standard histological procedures were followed for light microscopic examination. The lining epithelium of the trachea was found to be pseudostratified ciliated columnar (PSCC). Three types of cells were easily identified, basal and ciliated as well as few goblet cells interspersed among the ciliated cells and they were not clearly recognizable. A few tracheal seromucous glands were located at the free end of the C-shaped cartilaginous rings. The cartilaginous rings are replaced by smooth muscle cells before the bronchi enter into the lung. The lining epithelium of tracheobronchial tree gradually changes into simple cuboidal epithelium that lacks goblet cells. However, the division of the tracheobronchial tree is similar to other mammalian species. On the other hand, the principal bronchus lacks cartilaginous plaques as it becomes intrapulmonary bronchus. The wall of the bronchi is supported by thick layers of spirally arranged smooth muscles. Two types of cells were readily recognizable: basal and ciliated cells, with rarely observed goblet cells. In addition, the PSCC epithelium changes into simple cuboidal much earlier in the bronchial division relative to other species.

Wnt Signaling Regulates Airway Epithelial Stem Cells in Adult Murine Submucosal Glands.

Wnt signaling is required for lineage commitment of glandular stem cells (SCs) during tracheal submucosal gland (SMG) morphogenesis from the surface airway epithelium (SAE). Whether similar Wnt-dependent processes coordinate SC expansion in adult SMGs following airway injury remains unknown. We found that two Wnt-reporters in mice (BAT-gal and TCF/Lef:H2B-GFP) are coexpressed in actively cycling SCs of primordial glandular placodes and in a small subset of adult SMG progenitor cells that enter the cell cycle 24 hours following airway injury. At homeostasis, these Wnt reporters showed nonoverlapping cellular patterns of expression in the SAE and SMGs. Following tracheal injury, proliferation was accompanied by dynamic changes in Wnt-reporter activity and the analysis of 56 Wnt-related signaling genes revealed unique temporal changes in expression within proximal (gland-containing) and distal (gland-free) portions of the trachea. Wnt stimulation in vivo and in vitro promoted epithelial proliferation in both SMGs and the SAE. Interestingly, slowly cycling nucleotide label-retaining cells (LRCs) of SMGs were spatially positioned near clusters of BAT-gal positive serous tubules. Isolation and culture of tet-inducible H2B-GFP LRCs demonstrated that SMG LRCs were more proliferative than SAE LRCs and culture expanded SMG-derived progenitor cells outcompeted SAE-derived progenitors in regeneration of tracheal xenograft epithelium using a clonal analysis competition assay. SMG-derived progenitors were also multipotent for cell types in the SAE and formed gland-like structures in xenografts. These studies demonstrate the importance of Wnt signals in modulating SC phenotypes within tracheal niches and provide new insight into phenotypic differences of SMG and SAE SCs. Stem Cells 2016;34:2758-2771.