Bronchioles Research Articles

Diffuse Panbronchiolitis after Lung Transplantation. A New Form of Acute Rejection?

<h3>Introduction</h3> Diffuse panbronchiolitis is a chronic airway disease characterized by diffuse inflammation of respiratory bronchioles and peribronchial tissue. It is common in east Asia We present the case of diffuse panbronchiolitis that developed in 6 months in a female recipient who underwent sequential double lung transplantation from a brain-dead female donor. Both the recipient and the donor was caucasion. <h3>Case Report</h3> A 52-year-old woman who had sequential double lung transplantation 6 months ago due to lymphangioleiomyomatosis was admitted to the clinic with complaints of weakness, shortness of breath and productive cough. A restrictive type and severe loss was detected in pulmonary function test. Thorax computed tomography showed an appearance of a budding branch pattern, mainly in the lower lobes of both lungs. Transbronchial biopsy were performed and peribronchial lung parenchyma, which preserved its normal histological structure, was observed. Right thoracotomy and wedge biopsy from the lower lobe was performed in the patient because her clinical condition was unresponsive to medical treatment. Dense lymphocyte infiltration in the respiratory bronchiole wall and foamy macrophage groups in the adjacent interstitial area were detected in the pathological evaluation. Pulse steroid therapy was applied to the patient and dramatic clinical response was observed. <h3>Summary</h3> Pathologically proven Diffuse Panbronchiolitis in a lung transplant patient has not been published before. We present a unıque case suggesting acute rejection with the course of the disease and its response to the treatment.

Profile of Diabetic Patients Subjected for Spirometry

Introduction: When the air passes through the nasal cavity and pharynx, it gets warmed and takes up water vapour. And it passes down the trachea and through bronchioles, respiratory bronchioles and alveolar ducts to the alveoli. Between the trachea and the alveolar sacs, the airway divides 23 times forming 23 generations. The first 16 generations form the conducting zone of the airways made up of bronchi, bronchioles and terminal bronchioles. The remaining 7 generations from the transitional and respiratory zones where gas exchange occur and are made up of respiratory bronchioles, alveolar ducts and alveoli. Methodology: Information will be collected through a pre tested and structured proforma for each patient Qualifying patients will be undergoing detailed history, clinical examination, routine investigations like FBS, PPBS, HBA1c, fundus evaluation and spirometric evaluation using a easy one flow spirometer Glycemic control is taken as HBA1C below 7.5 and HBA1C more than 7.5 is considered as uncontrolled sugars. Results: Group 1 had 15 patients with uncontrolled sugars i.e HbA1c of more than 7.5 Group 2 had 26 patients with HbA1c of more than 7.5, out of 70 patients of type 2 DM, 41 (58.6%) patients had HBA1C of more than 7.5. Conclusion: Diabetes mellitus leads to increased hepatic glucose output. First, liver glycogen stores are mobilised then hepatic gluconeogenesis is used to produce glucose. Insulin deficiency also impairs non-hepatic tissue utilization of glucose, particularly in adipose tissue and skeletal muscle, insulin stimulates glucose uptake.

Synchrotron Radiation-Based Refraction-Contrast Tomographic Images Using X-ray Dark-Field Imaging Optics in Human Lung Adenocarcinoma and Histologic Correlations.

The aim of this study was to evaluate the clinical implication of synchrotron radiation imaging techniques for human lung adenocarcinoma in comparison with pathologic examination. A refraction-based tomographic imaging technique called the X-ray dark-field imaging (XDFI) method was used to obtain computed tomographic images of human lung adenocarcinoma at the beam line at Photon Factory BL 14B at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. Images of normal lung tissue were also obtained using the same methods and reconstructed as 3D images. Both reconstructed images were compared with pathologic examinations from histologic slides which were made with identical samples. Pulmonary alveolar structure including terminal bronchioles, alveolar sacs, and vasculatures could be identified in synchrotron radiation images of normal lung. Hyperplasia of interstitial tissue and dysplasia of alveolar structures were noticed in images of lung adenocarcinoma. Both synchrotron radiation images were considerably correlated with images from histologic slides. Lepidic patterns of cancer tissue were distinguished from the invasive area in synchrotron radiation images of lung adenocarcinoma. Refraction-contrast tomographic techniques using synchrotron radiation could provide high-resolution images of lung adenocarcinoma which are compatible with those from pathologic examinations.

Features of the macro and microscopic structure of the lungs of a mature rabbit – Oryctolagus cuniculus L. 1758

The macro- and microscopic structure of the lungs of mature rabbits – Oryctolagus cuniculus L., 1758 – European rabbit was studied. This work was performed using comprehensive research methods: anatomical, organometric, histological and histometric. The research was carried out in the conditions of the laboratory of pathomorphology in the Department of Anatomy and Histology. The scientific work was performed on the subject of research work of the Department of Anatomy and Histology of Polissya National University on the theme: “Development, morphology and histochemistry of animal organs in normal and pathological”, according to the state registration number – № 0113V000900. The morphological studies followed the basic rules of Good Laboratory Practice GLP (1981), the provisions of the “General Ethical Principles of Animal Experiments”, adopted by the First National Congress of Bioethics (Kyiv, 2001) and the requirements for the “Rules for carrying out work with experimental animals”, approved by the order of the Ministry of Health № 281 of November 1, 2000 “On measures to further improve the organizational forms of work with the use of experimental animals”. The material for histomorphological studies were pieces of lungs selected from clinically healthy adult rabbits (n = 5). Slices were made from paraffin blocks on a sled microtome MS–2. The thickness of histological sections did not exceed 8–12 μm, which were then stained with hematoxylin and eosin and Van Gizon to study the morphofunctional activity of cells and tissues of the respiratory tract. Histometric studies of histological specimens were performed using a microscope “Micros” with a digital camera at a magnification of × 100–1000. Studies have shown that macroscopically the lungs of mature rabbits have a reflection of the shape of the thoracic cavity, and gradually expands ventrally. The right and left lungs are surrounded by pleural right and left sacs. The pleural cavities of both lungs in the test animals are not interconnected. Organometry showed that the absolute lung mass of rabbits is 18.05 ± 1.32 g, relative to 0.624 ± 0.013 %. The histoarchitectonics of the lungs is formed by the lung lobes. The respiratory department of the lungs is represented by a set of acinuses. The latter are represented by respiratory bronchioles, alveolar passages, alveolar sacs and alveoli that form the alveolar tree. The results of morphometric studies showed that the respiratory (respiratory) part of the lungs of rabbits occupies 39.6 ± 0.62 %, and the connective tissue base, respectively, 58.5 ± 1.27 %. The average volume of alveoli, which are divided into small, medium and large, is 42.3 ± 4.35 thousand μm3. Thus, studies of the macro- and microscopic structure of the lungs of experimental animals are of great general biological importance, as they are an important criterion for objective assessment for the differential diagnosis of diseases of various origins.

Proposal of selective wedge instillation of pulmonary surfactant for COVID-19 pneumonia based on computational fluid dynamics simulation

BackgroundThe most important target cell of SARS-CoV-2 is Type II pneumocyte which produces and secretes pulmonary surfactant (PS) that prevents alveolar collapse. PS instillation therapy is dramatically effective for infant respiratory distress syndrome but has been clinically ineffective for ARDS. Nowadays, ARDS is regarded as non-cardiogenic pulmonary edema with vascular hyper-permeability regardless of direct relation to PS dysfunction. However, there is a possibility that this ineffectiveness of PS instillation for ARDS is caused by insufficient delivery. Then, we performed PS instillation simulation with realistic human airway models by the use of computational fluid dynamics, and investigated how instilled PS would move in the liquid layer covering the airway wall and reach to alveolar regions.MethodsTwo types of 3D human airway models were prepared: one was from the trachea to the lobular bronchi and the other was from a subsegmental bronchus to respiratory bronchioles. The thickness of the liquid layer covering the airway was assigned as 14 % of the inner radius of the airway segment. The liquid layer was assumed to be replaced by an instilled PS. The flow rate of the instilled PS was assigned a constant value, which was determined by the total amount and instillation time in clinical use. The PS concentration of the liquid layer during instillation was computed by solving the advective-diffusion equation.ResultsThe driving pressure from the trachea to respiratory bronchioles was calculated at 317 cmH2O, which is about 20 times of a standard value in conventional PS instillation method where the driving pressure was given by difference between inspiratory and end-expiratory pressures of a ventilator. It means that almost all PS does not reach the alveolar regions but moves to and fro within the airway according to the change in ventilator pressure. The driving pressure from subsegmental bronchus was calculated at 273 cm H2O, that is clinically possible by wedge instillation under bronchoscopic observation.ConclusionsThe simulation study has revealed that selective wedge instillation under bronchoscopic observation should be tried for COVID-19 pneumonia before the onset of ARDS. It will be also useful for preventing secondary lung fibrosis.

A Rare Presentation of a Rare Case: Acute Respiratory Failure in Swyer-James-Macleod Syndrome

Swyer-James-Macleod syndrome (SJMS) is a rare clinical entity acquired during childhood due to a respiratory infection leading to bronchiolitis obliterans. This inciting event is hypothesized to cause structural and functional changes of the developing alveoli, terminal bronchioles, and the corresponding pulmonary vasculature, resulting in emphysematous changes and a matched ventilation-perfusion defect. We present a 67-year-old male patient with hypercapnic respiratory failure requiring invasive mechanical ventilation, who had typical features of SJMS undiagnosed before this admission. He was extubated successfully, discharged home, and continues to be stable at a 90-day follow-up period. This marks one of the rare accounts where a patient with SJMS was given ventilatory support emergently, and one of the oldest patients reported. SJMS is under-reported due to its indolent clinical course and misdiagnosed as some other pulmonary abnormality. The clinical course progression and prognosis are unclear and variable in many affected patients due to this condition's rarity.

Lung tissue inflammatory response and pneumonocyte apoptosis of Sprague-Dawley rats after a 30-day exposure in methyl mercaptan vapor

ABSTRACT The objective of the research was to reveal the potential toxicity effects of methyl mercaptan on rat lung tissue. A dynamic exposure device and Sprague-Dawley (SD) rats were adopted. The exposure concentration of methyl mercaptan was 0.5 ± 0.1 ppm. The exposure procedure was 6 h/day, continuing for 30 days. The routine blood levels, oxidative stress levels in serum, immune molecule and cytokine in the serum and lung tissue were tested. Morphology injury of lung tissue was detected by Hematoxylin and Eosin (HE) staining. Apoptosis rate of alveolar epithelial cells were determined by TdT-mediated dUTP Nick End Labeling (TUNEL) assay. Reduction of body weight gain was observed in the male group during the exposure time, while there was no significant reduction of body weight gain in the female group. Pathological findings of terminal bronchiole constriction, alveolar congestion, and erythrocyte exudation confirmed the lung to be the main target organ. An apparent pneumonocyte apoptotic effection was also observed. Oxidative stress with lipid peroxidation, which affect blood antioxidant enzyme levels and induce apoptosis of alveolar epithelial cells, are recognized as a potential mechanism leading to terminal bronchiole constriction, alveoli congestion, and exudates of erythrocyte. Implications: The odor pollutants greatly affect the health of operation workers in the waste treatment plant, and odor complaints are becoming a major problem. The aim of this work is to identify the lung tissue inflammatory response of SD rats with chronic exposure to methyl mercaptan vapor at close to the recommended workplace concentration. In this study, we used a dynamic exposure device and chronic exposure model of rats to evaluate the potential toxicity effects of methyl mercaptan. The results showed that methyl mercaptan may cause lung inflammatory response and extensive lung cell apoptosis. Oxidative damage, with lipid peroxidation and alterations in blood antioxidant enzyme levels, was observed following methyl mercaptan exposure. This is recognized as a potential mechanism for terminal bronchiolar constriction, alveolar congestion, and erythrocyte exudation.

Bronchiectasis is one of the indicators of severe coronavirus disease 2019 pneumonia.

Bronchiectasis is one of the indicators of severe coronavirus disease 2019 pneumonia.

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist

Distinct Airway Involvement in Subtypes of End-Stage Fibrotic Pulmonary Sarcoidosis

Sarcoidosis is a systemic granulomatous disease that in most cases affects the lung. Pulmonary fibrotic sarcoidosis is clinically, radiologically and pathologically a heterogeneous condition. Although there is substantial indirect evidence of small airway involvement, direct evidence is currently lacking. to investigate the role of the (small) airways in fibrotic sarcoidosis. and methods: Airway morphology was investigated in 7 explant lungs with end-stage fibrotic sarcoidosis using a combination of CT (large airways), microCT (small airways) and histology and compared to 7 unused donor lungs as controls with specific attention for different radiologically defined sarcoidosis subtypes. Patients with central bronchial distortion (n=3), diffuse bronchiectasis (n=3) and UIP pattern (n=1) were identified based on CT scan, showing respectively a decrease and narrowing of large airways, a similar airway number and increased airway diameter of more distal airways or an increase in airway number and airway diameter compared to controls. The number of terminal bronchioles/mL and total number of terminal bronchioles were decreased in all forms of fibrotic sarcoidosis. Interestingly, the number of terminal bronchioles was inversely correlated with the degree of fibrosis. Furthermore, we identified granulomatous remodeling as a cause of small airway loss using serial microCT and histology. The large airways are differentially involved in subtypes of sarcoidosis, but the terminal bronchioles are universally lost. This suggests that small airway loss forms an important aspect in the pathophysiology of fibrotic pulmonary sarcoidosis.

Pulmonary Cystic Adenomatoid Malformation, Prenatal Diagnosis and Case Management

The Cystic Adenomatous Malformation (CAM) is a rare fetal lung lesion. Its frequency is about 1 in 4000 births and is characterized by an overgrowth of terminal respiratory bronchioles that forms cysts of various sizes. It can be associated with polyhydramnios and pulmonary hypoplasia. We describe here a case of Adenoid Cystic Pulmonary Malformation type II with prenatal diagnosis at 20 weeks of gestational age, as well as its subsequent management. Morphological ultrasound describes multiple small cysts associated with a slight mediastinal deviation. The prognosis depends mainly on the associated injuries. Prenatal ultrasound allows early diagnosis and follow-up of CCAM to monitor the appearance of possible pathophysiological complications that may worsen its prognosis.

Morphometric characteristics of distal airways of guinea pigs sensitized with ovalbumin

The reaction of the structural components of small bronchi and terminal bronchioles is the urgent issue of morphology and medicine in general, as well as one of the insufficiently studied issue in the study of morphological changes in the airways with allergic inflammation in the chronobiological aspect. The purpose of this work is to study the morphometric parameters of distal airways of guinea pigs sensitized with ovalbumin. We have studied the lung of 48 guinea pigs, using histological, morphometric and statistical methods under conditions of experimental ovalbumin-induced allergic inflammation, simulated by three times subcutaneous sensitization and subsequent 8-day intranasal inhalation of ovalbumin. The thickness of mucosa, muscular layer and adventitial layer was determined to assess morphometric parameters of bronchioles and terminal bronchioles. There are reactive changes in morphometric parameters of bronchioles on the 23rd and 30th days of observation, such as the thinning of mucosa and on the 36th day such as muscular-fibrous hyperplasia, accompanied by the narrowing of the bronchioles lumen. There are the most significant confirmed statistically changes in the terminal bronchioles on the 36th day of the experiment such as the thickening of mucosa and adventitial layer, accompanied by muscular hyperplasia and edema of the connective tissue stroma. Thus, sensitization and allergization with ovalbumin of experimental animals cause morpho-functional changes in the structural elements of the wall of bronchioles and terminal bronchioles, which have a staged, mainly multidirectional character and correspond to the main morphological manifestations of allergic inflammation with maximal changes in the late period of its development (the 36th day of the experiment).

Microscopic anatomical, immunohistochemical, and morphometric characterization of the terminal airways of the lung in cetaceans.

The lungs of cetaceans undergo anatomical and physiological adaptations that facilitate extended breath-holding during dives. Here, we present new insights on the ontogeny of the microscopic anatomy of the terminal portion of the airways of the lungs in five cetacean species: the fin whale (Balaenoptera physalus); the sperm whale (Physeter macrocephalus), the Cuvier's beaked whale (Ziphius cavirostris); the bottlenose dolphin (Tursiops truncatus); and the striped dolphin (Stenella coeruleoalba). We (a) studied the histology of the terminal portion of the airways; (b) used immunohistochemistry (IHC) to characterize the muscle fibers with antibodies against smooth muscle (sm-) actin, sm-myosin, and desmin; (c) the innervation of myoelastic sphincters (MESs) with an antibody against neurofilament protein; and (d) defined the diameter of the terminal bronchioles, the diameter and length of the alveoli, the thickness of the septa, the major and minor axis, perimeter and section area of the cartilaginous rings by quantitative morphometric analyses in partially inflated lung tissue. As already reported in the literature, in bottlenose and striped dolphins, a system of MESs was observed in the terminal bronchioles. Immunohistochemistry confirmed the presence of smooth muscle in the terminal bronchioles, alveolar ducts, and alveolar septa in all the examined species. Some neurofilaments were observed close to the MESs in both bottlenose and striped dolphins. In fin, sperm, and Cuvier's beaked whales, we noted a layer of longitudinal smooth muscle going from the terminal bronchioles to the alveolar sacs. The morphometric analysis allowed to quantify the structural differences among cetacean species by ranking them into groups according to the adjusted mean values of the morphometric parameters measured. Our results contribute to the current understanding of the anatomy of the terminal airways of the cetacean lung and the role of the smooth muscle in the alveolar collapse reflex, crucial for prolonged breath-holding diving.

Progenitor identification and SARS-CoV-2 infection in human distal lung organoids.

The distal lung contains terminal bronchioles and alveoli that facilitate gas exchange. Three-dimensional in vitro human distal lung culture systems would strongly facilitate the investigation of pathologies such as interstitial lung disease, cancer and coronavirus disease 2019 (COVID-19) pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here we describe the development of a long-term feeder-free, chemically defined culture system for distal lung progenitors as organoids derived from single adult human alveolar epithelial type II (AT2) or KRT5+ basal cells. AT2 organoids were able to differentiate into AT1 cells, and basal cell organoids developed lumens lined with differentiated club and ciliated cells. Single-cell analysis of KRT5+ cells in basal organoids revealed a distinct population of ITGA6+ITGB4+ mitotic cells, whose offspring further segregated into a TNFRSF12Ahi subfraction that comprised about ten per cent of KRT5+ basal cells. This subpopulation formed clusters within terminal bronchioles and exhibited enriched clonogenic organoid growth activity. We created distal lung organoids with apical-out polarity to present ACE2 on the exposed external surface, facilitating infection of AT2 and basal cultures with SARS-CoV-2 and identifying club cells as a target population. This long-term, feeder-free culture of human distal lung organoids, coupled with single-cell analysis, identifies functional heterogeneity among basal cells and establishes a facile in vitro organoid model of human distal lung infections, including COVID-19-associated pneumonia.

Patho-morphological and immunohistochemical diagnosis of fibrous tissue pulmonary hamartoma in young buffaloes

ABSTRACT Hamartoma is a developmental disorder characterized by the presence of well-differentiated tissue, of multiple types, in excess at its normal location. The present study describes a fibrous tissue pulmonary hamartoma in two buffaloes. Grossly, there were large pale white masses present on the left diaphragmatic lobe in both cases. Microscopic examination of the lungs revealed that the bronchioles were dilated and showed many terminal respiratory bronchioles lined by a single layer of cuboidal epithelium supported by thick bands of collagenous tissue. Alveoli were distorted and separated by wide bands of connective tissues. Interalveolar septa were greatly expanded by collagen fiber proliferation and subsequent fibrosis. Fibrous connective tissues were demonstrated by immunohistochemistry (IHC) and Masson’s Trichrome staining (MTS). Based on gross and histological examination, coupled with IHC and MTS, it was possible to confirm a case of hamartoma, which is rarely reported worldwide and is the first reported case from India.

Long-Term Nonclinical Pulmonary Safety Assessment of Afrezza, a Novel Insulin Inhalation Powder.

Afrezza delivers inhaled insulin using the Gen2 inhaler for the treatment of patients with type 1 and type 2 Diabetes. Afrezza was evaluated in long-term nonclinical pulmonary safety studies in 2 toxicology species. Chronic inhalation toxicology studies in rat (26 weeks) and dog (39 weeks) and an inhalation carcinogenicity study in rats were conducted with Technosphere insulin (Afrezza) and with Technosphere alone as a vehicle control. Respiratory tract tissues were evaluated by histopathology and cells expressing proliferating cell nuclear antigen (PCNA) were quantified in lungs of rats. Microscopic findings in rats exposed to Afrezza were attributed to the Technosphere particle component, were confined to nasal epithelia, and consisted of eosinophilic globules and nasal epithelial degeneration. There were no Afrezza-related changes in pulmonary PCNA labeling indices in alveoli, large bronchioles, or terminal bronchioles. Microscopic findings in rats exposed to Technosphere particles included eosinophilic globules, mucus cell hyperplasia, and epithelial degeneration in the nasal cavities. PCNA labeling indices were increased in large bronchioles and terminal bronchioles but not in alveoli. There were no Technosphere particle-related findings in the dog study. Afrezza did not exhibit carcinogenic potential in the 2-year study in rats. These nonclinical inhalation studies support the use of Afrezza in humans over extended periods.

Small airway loss in the physiologically ageing lung: a cross-sectional study in unused donor lungs

Physiological lung ageing is associated with a gradual decline in dynamic lung volumes and a progressive increase in residual volume due to diminished elastic recoil of the lung, loss of alveolar tissue, and lower chest wall compliance. However, the effects of ageing on the small airways (ie, airways <2·0 mm in diameter) remain largely unknown. By using a combination of ex-vivo conventional CT (resolution 1 mm), whole lung micro-CT (resolution 150 μm), and micro-CT of extracted cores (resolution 10 μm), we aimed to provide a multiresolution assessment of the small airways in lung ageing in a large cohort of never smokers. For this cross-sectional study, we included donor lungs collected from 32 deceased never-smoking donors (age range 16-83 years). Ex-vivo CT and whole lung high-resolution CT (micro-CT) were used to determine total airway numbers, stratified by airway diameter. Micro-CT was used to assess the number, length, and diameter of terminal bronchioles (ie, the last generation of conducting airways); mean linear intercept; and surface density in four lung tissue cores from each lung, extracted using a uniform sampling approach. Regression β coefficients are calculated using linear regression and polynomial models. Ex-vivo CT analysis showed an age-dependent decrease in the number of airways of diameter 2·0 mm to less than 2·5 mm (β coefficient per decade -0·119, 95% CI -0·193 to -0·045; R2=0·29) and especially in airways smaller than 2·0 mm in diameter (-0·158, -0·233 to -0·084; R2=0·47), between 30 and 80 years of age, but not of the larger (≥2·5 mm) diameter airways (-0·00781, -0·04409 to 0·02848; R2=0·0007). In micro-CT analysis of small airways, the total number of terminal bronchioles per lung increased until the age of 30 years, after which an almost linear decline in the number of terminal bronchioles was observed (β coefficient per decade -2035, 95% CI -2818 to -1252; R2=0·55), accompanied by a non-significant increase in alveolar airspace size (6·44, -0·57 to 13·45, R2=0·10). Moreover, this decrease in terminal bronchioles was associated with the age-related decline of pulmonary function predicted by healthy reference values. Loss of terminal bronchioles is an important structural component of age-related decline in pulmonary function of healthy, non-smoking individuals. Research Foundation-Flanders, KU Leuven, Parker B Francis Foundation, UGent, Canadian Institutes for Health.

Bronchioalveolar stem cells derived from mouse-induced pluripotent stem cells promote airway epithelium regeneration

BackgroundBronchioalveolar stem cells (BASCs) located at the bronchioalveolar-duct junction (BADJ) are stem cells residing in alveoli and terminal bronchioles that can self-renew and differentiate into alveolar type (AT)-1 cells, AT-2 cells, club cells, and ciliated cells. Following terminal-bronchiole injury, BASCs increase in number and promote repair. However, whether BASCs can be differentiated from mouse-induced pluripotent stem cells (iPSCs) remains unreported, and the therapeutic potential of such cells is unclear. We therefore sought to differentiate BASCs from iPSCs and examine their potential for use in the treatment of epithelial injury in terminal bronchioles.MethodsBASCs were induced using a modified protocol for differentiating mouse iPSCs into AT-2 cells. Differentiated iPSCs were intratracheally transplanted into naphthalene-treated mice. The engraftment of BASCs into the BADJ and their subsequent ability to promote repair of injury to the airway epithelium were evaluated.ResultsFlow cytometric analysis revealed that BASCs represented ~ 7% of the cells obtained. Additionally, ultrastructural analysis of these iPSC-derived BASCs via transmission electron microscopy showed that the cells containing secretory granules harboured microvilli, as well as small and immature lamellar body-like structures. When the differentiated iPSCs were intratracheally transplanted in naphthalene-induced airway epithelium injury, transplanted BASCs were found to be engrafted in the BADJ epithelium and alveolar spaces for 14 days after transplantation and to maintain the BASC phenotype. Notably, repair of the terminal-bronchiole epithelium was markedly promoted after transplantation of the differentiated iPSCs.ConclusionsMouse iPSCs could be differentiated in vitro into cells that display a similar phenotype to BASCs. Given that the differentiated iPSCs promoted epithelial repair in the mouse model of naphthalene-induced airway epithelium injury, this method may serve as a basis for the development of treatments for terminal-bronchiole/alveolar-region disorders.

In Vitro and In Vivo Evaluation of the Toxic Effects of Dodecylguanidine Hydrochloride.

The toxicity profiles of the widely used guanidine-based chemicals have not been fully elucidated. Herein, we evaluated the in vitro and in vivo toxicity of eight guanidine-based chemicals, focusing on inhalation toxicity. Among the eight chemicals, dodecylguanidine hydrochloride (DGH) was found to be the most cytotoxic (IC50: 0.39 μg/mL), as determined by the water soluble tetrazolium salts (WST) assay. An acute inhalation study for DGH was conducted using Sprague-Dawley rats at 8.6 ± 0.41, 21.3 ± 0.83, 68.0 ± 3.46 mg/m3 for low, middle, and high exposure groups, respectively. The levels of lactate dehydrogenase, polymorphonuclear leukocytes, and cytokines (MIP-2, TGF-β1, IL-1β, TNF-α, and IL-6) in the bronchoalveolar lavage fluid increased in a concentration-dependent manner. Histopathological examination revealed acute inflammation with necrosis in the nasal cavity and inflammation around terminal bronchioles and alveolar ducts in the lungs after DGH inhalation. The LC50 of DGH in rats after exposure for 4 h was estimated to be >68 mg/m3. Results from the inhalation studies showed that DGH was more toxic in male rats than in female rats. Overall, DGH was found to be the most cytotoxic chemical among guanidine-based chemicals. Exposure to aerosols of DGH could induce harmful pulmonary effects on human health.

Pathology of Idiopathic Pulmonary Fibrosis Assessed by a Combination of Microcomputed Tomography, Histology, and Immunohistochemistry

Idiopathic pulmonary fibrosis (IPF) is a fibrotic disease with the histology of usual interstitial pneumonia (UIP). Although the pathologist's visual inspection is central in histologic assessments, three-dimensional microcomputed tomography (microCT) assessment may complement the pathologist's scoring. We examined associations between the histopathologic features of UIP and IPF in explanted lungs and quantitative microCT measurements, including alveolar surface density, total lung volume taken up by tissue (%), and terminal bronchiolar number. Sixty frozen samples from 10 air-inflated explanted lungs with severe IPF and 36 samples from 6 donor control lungs were scanned with microCT and processed for histologic analysis. An experienced pathologist scored three major UIP criteria (patchy fibrosis, honeycomb, and fibroblastic foci), five additional pathologic changes, and immunohistochemical staining for CD68-, CD4-, CD8-, and CD79a-positive cells, graded on a 0 to 3+ scale. The alveolar surface density and terminal bronchiolar number decreased and the tissue percentage increased in lungs with IPF compared with controls. In lungs with IPF, lower alveolar surface density and higher tissue percentage were correlated with greater scores of patchy fibrosis, fibroblastic foci, honeycomb, CD79a-positive cells, and lymphoid follicles. A decreased number of terminal bronchioles was correlated with honeycomb score but not with the other scores. The three-dimensional microCT measurements reflect the pathological UIP and IPF criteria and suggest that the reduction in the terminal bronchioles may be associated with honeycomb cyst formation.