An immimohistochemical study of regulatory peptides in lungs of amphibians

Summary The lungs of five species of European Anura and one species of Urodela (Triturus alpestris) have been studied by immunohistochemical methods to determine the occurrence, localization and distribution of serotonin, neuron-specific enolase, and eight regulatory peptides reported in the mammalian respiratory tract.Single and groups of serotonin-immunoreactive cells, corresponding to neuroendocrine cells of the mammalian lung, were identified in lungs of all amphibian species studied. Immunoreactivity for neuron-specific enolase was localized mainly in pulmonary nerves, nerve cell bodies and neuroendocrine cells. The localization and distribution of regulatory peptides varied among species. Bombesin and gastrin-releasing peptide immunoreactivities (predominant peptides in human lung) were localized mostly in submucosal nerves. Single bombesin-immunoreactive cells were found only in lungs of Urodela, i.e., Triturus alpestris. Occasional single cells, immunoreactive for somatostatin and leu-enkephalin were identified in lungs of Bombina variegata and a few cholecystokinin-immunoreactive cells in Hyla arborea. In all anuran species, numerous substance P-immunoreactive nerves were identified in submucosa, pulmonary septa and around blood vessels. No immunoreactive cells or nerves were demonstrated with antibodies against calcitonin and vasoactive intestinal peptide.The term pulmonary neuroendocrine (NE) cells (used here) does not imply neural origin or classical endocrine function for these cells, but rather indicates their potential involvement in neurohormonal regulation of pulmonary function (Cutz 1982)Supported by grant to E.C. from Medical Research Council of Canada (MT-7641)     

Expression of plgR in the tracheal mucosa of SHIV/SIV-infected rhesus macaques

Polymeric immunoglobulin receptors (plgR) are key participants in the formation and secretion of secretory IgA (S-IgA),which is critical for the prevention of microbial infection and colonization in the respiratory system.Although increased respiratory colonization and infections are common in HIV/AIDS,little is known about the expression of plgR in the airway mucosa of these patients.To address this,the expression levels of plgR in the tracheal mucosa and lungs of SHIV/SIV-infected rhesus macaques were examined by real-time RT-PCR and confocal microscopy.We found that the levels of both PIGR mRNA and plgR immunoreactivity were lower in the tracheal mucosa of SHIV/SIV-infected rhesus macaques than that in non-infected rhesus macaques,and the difference in plgR immunoreactivity was statistically significant.IL-17A,which enhances plgR expression,was also changed in the same direction as that of plgR.In contrast to changes in the tracheal mucosa,plgR and IL-17A levels were higher in the lungs of infected rhesus macaques.These results indicated abnormal plgR expression in SHIV/SIV,and by extension HIV infections,which might partially result from IL-17A alterations and might contribute to the increased microbial colonization and infection related to pulmonary complications in HIV/AIDS.     

Ionotropic GABA receptor expression in the lung during development

Cl(-) transport is essential for lung development. Because gamma-aminobutyric acid (GABA) receptors allow the flow of negatively-charged Cl(-) ions across the cell membrane, we hypothesized that the expression of ionotropic GABA receptors are regulated in the lungs during development. We identified 17 GABA receptor subunits in the lungs by real-time PCR. These subunits were categorized into four groups: Group 1 had high mRNA expression during fetal stages and low in adults; Group 2 had steady expression to adult stages with a slight up-regulation at birth; Group 3 showed an increasing expression from fetal to adult lungs; and Group 4 displayed irregular mRNA fluctuations. The protein levels of selected subunits were also determined by Western blots and some subunits had protein levels that corresponded to mRNA levels. Further studied subunits were primarily localized in epithelial cells in the developing lung with differential mRNA expression between isolated cells and whole lung tissues. Our results add to the knowledge of GABA receptor expression in the lung during development.     

Defining lung cancer stem cells exosomal payload of miRNAs in clinical perspective

Since the first publication regarding the existence of stem cells in cancer [cancer stem cells(CSCs)] in 1994, many studies have been published providing in-depth information about their biology and function. This research has paved the way in terms of appreciating the role of CSCs in tumour aggressiveness, progression,recurrence and resistance to cancer therapy. Targeting CSCs for cancer therapy has still not progressed to a sufficient degree, particularly in terms of exploring the mechanism of dynamic interconversion between CSCs and non-CSCs. Besides the CSC scenario, the problem of cancer dissemination has been analyzed indepth with the identification and isolation of microRNAs(miRs), which are now considered to be compelling molecular markers in the diagnosis and prognosis of tumours in general and specifically in patients with non-small cell lung cancer.Paracrine release of miRs via "exosomes"(small membrane vesicles(30-100 nm),the derivation of which lies in the luminal membranes of multi-vesicular bodies)released by fusion with the cell membrane is gaining popularity. Whether exosomes play a significant role in maintaining a dynamic equilibrium state between CSCs and non-CSCs and their mechanism of activity is as yet unknown.Future studies on CSC-related exosomes will provide new perspectives for precision-targeted treatment strategies.     

Unidirectional flow in lizard lungs: a paradigm shift in our understanding of lung evolution in Diapsida

Conventional wisdom has held that unidirectional pulmonary airflow is unique to birds and is an adaption enabling high rates of gas exchange, essential for sustaining flight as well as an endothermic metabolism. Recent visualizations and measurements of flow in the lungs of monitor and iguanid lizards show a bird-like pattern of unidirectional flow in these lineages. These findings call for a paradigm shift in our understanding of lung evolution in diapsids. This pattern of flow is not unique to birds. It is much older than previously believed, and it may be advantageous to the low-energy lifestyles typical of ectothermic animals.     

Lungs and mesopneumonia of scincomorph lizards (Reptilia: Squamata)

Mesopneumonia of 28 and lungs of 44 species of scincomorph lizards are described, representing mesopneumonia in six of the seven scincomorph families and lungs of all seven families of this taxon. Except for gymnophthalmids and scincids, a family typical organization of mesopneumonia occurs. In cordylids, gerrhosaurids, xantusiids and lacertids the complete right ventral mesopneumonium (VMp) inserts cranially on the posterior vena cava and caudally on the dorsal surface of the right liver lobe. The left VMp is attached to the ventrolateral body wall in cordylids and lacertids; in gerrhosaurids the left VMp is short and inserts on the pericardium and the posterior vena cava; in xantusiids the left VMp is reduced and the lungs are fused cranially with the pericardium. In scincids the VMp of both sides vary in length and insert on the ventral mesentery, or may be lacking completely. The visceral topology of the gymnophthalmids Calyptommatus and Notobachia differs from the general scincomorph pattern, with the liver and stomach elongated and situated on the right and left side of the body cavity, respectively. The left and the right VMp extend over the entire length of the lungs and insert on the ventral mesentery. All lungs examined in the study are single-chambered and show no major structural variability of the inner surfaces, except in lacertids, some gerrhosaurids, Cordylus, and two genera of gymnophthalmids (Echinosaura and Neusticurus). In these groups, rows of dorsomedial niches are present.See also Electronic Supplement at: http://www.senckenberg.de/odes/05-06.htm     

The efficacy of ice recrystallization inhibitors in rat lung cryopreservation using a low cost technique for ex vivo subnormothermic lung perfusion

Although lung transplant remains the only option for patients with end-stage lung failure, short preservation times result in an inability to meet patient demand. Successful cryopreservation may ameliorate this problem; however, very little research has been performed on lung cryopreservation due to the inability to prevent ice nucleation or growth. Therefore, this research sought to characterize the efficacy of a small-molecule ice recrystallization inhibitor (IRI) for lung cryopreservation given its well-documented ability to control ice growth.Sprague-Dawley heart-lung blocks were perfused at room temperature using a syringe-pump. Cytotoxicity of the IRI was assessed through the subsequent perfusion with 0.4% (w/v) trypan blue followed by formalin-fixation. Ice control was assessed by freezing at a chamber rate of −5 °C/min to −20 °C and cryofixation using a low-temperature fixative. Post-thaw cell survival was determined by freezing at a chamber rate of −5 °C/min to −20 °C and thawing in a 37 °C water bath before formalin-fixation. In all cases, samples were paraffin-embedded, sliced, and stained with eosin.The IRI studied was found to be non-toxic, as cell membrane integrity following perfusion was not significantly different than controls (p = 0.9292). Alveolar ice grain size was significantly reduced by the addition of this IRI (p = 0.0096), and the addition of the IRI to DMSO significantly improved post-thaw cell membrane integrity when compared to controls treated with DMSO alone (p = 0.0034).The techniques described here provide a low-cost solution for rat ex vivo lung perfusion which demonstrated that the ice control and improved post-thaw cell survival afforded by IRI-use warrants further study.     

Evaluation of Diagnostic Value of Mediastinum for Differentiation of Drug Sensitive,Multi and Extensively Drug Resistant Tuberculosis Using Chest X-Rays

Background and ObjectiveThe rise of Drug Resistant Tuberculosis (DR TB), particularly Multi DR (MDR), and Extensively DR (XDR) has reduced the rate of control of the disease. Computer aided diagnosis using Chest X-rays (CXRs) can help in mass screening and timely diagnosis of DR TB, which is essential to administer proper treatment regimens. In CXRs, lungs and mediastinum are two significant regions which contain the information about the likelihood of DR TB. The objective of this work is to analyze the shape characteristics of lungs and mediastinum to improve the diagnostics accuracy for differentiation of Drug Sensitive (DS), MDR and XDR TB using computer aided diagnostics system.MethodsThe CXR images of DS and DR TB patients are obtained from a public database. The lung fields are segmented from the CXRs using Reaction Diffusion Level Set Evolution. Mediastinum is segmented from the delineated lung masks using Chan Vese model. The shape features from each lung and mediastinum masks are extracted and analysed. The discriminative power of individual and combination of both lung and mediastinum features are evaluated using machine learning techniques for classification of DS vs MDR, MDR vs XDR and DS vs XDR TB images. The performances of classifiers are compared using standard metrics.ResultsThe proposed segmentation methods are able to delineate lungs and mediastinum from the CXR images. The extracted lung and mediastinum features are found to be statistically significant (p < 0.05) for differentiation of DS and DR TB conditions. Using the combination of both lung and mediastinum features, Multi-Layer Perceptron classifier achieves maximum F-measure of 82.4%, 81.0% and 87.0% for differentiation of DS vs MDR, MDR vs XDR and DS vs XDR, respectively.ConclusionAnalysis of mediastinum along with the lungs in chest X-rays could improve the diagnostic performance for differentiation of drug sensitive and resistant TB conditions. The proposed methodology is able to differentiate DS, MDR and XDR TB, and found to be clinically relevant. Hence, this work is useful for computer-based early detection of DS and DR TB conditions.     

Mesenchymal stromal cells as potential immunomodulatory players in severe acute respiratory distress syndrome induced by SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus-2 and the related coronavirus disease-19 (COVID-19) is a worldwide emerging situation, which was initially reported in December 2019 in Wuhan, China. Currently, more than 7258842 new cases, and more than 411879 deaths have been reported globally. This new highly transmitted coronavirus is responsible for the development of severe acute respiratory distress syndrome. Due to this disorder, a great number of patients are hospitalized in the intensive care unit followed by connection to extracorporeal membrane oxygenation for breath supporting and survival. Severe acute respiratory distress syndrome is mostly accompanied by the secretion of proinflammatory cytokines, including interleukin (IL)-2, IL-6, IL-7, granulocyte colony-stimulating factor (GSCF), interferon-inducible protein 10 (IP10), monocyte chemotactic protein-1 (MCP1), macrophage inflammatory protein 1A (MIP1A), and tumor necrosis factor alpha (TNF-α), an event which is known as “cytokine storm”. Further disease pathology involves a generalized modulation of immune responses, leading to fatal multiorgan failure. Currently, no specific treatment or vaccination against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been developed. Mesenchymal stromal cells (MSCs), which are known for their immunosuppressive actions, could be applied as an alternative co-therapy in critically-ill COVID-19 patients. Specifically, MSCs can regulate the immune responses through the conversion of Th1 to Th2, activation of M2 macrophages, and modulation of dendritic cells maturation. These key immunoregulatory properties of MSCs may be exerted either by produced soluble factors or by cell-cell contact interactions. To date, several clinical trials have been registered to assess the safety, efficacy, and therapeutic potential of MSCs in COVID-19. Moreover, MSC treatment may be effective for the reversion of ground-glass opacity of damaged lungs and reduce the tissue fibrosis. Taking into account the multifunctional properties of MSCs, the proposed stem-cell-based therapy may be proven significantly effective in critically-ill COVID-19 patients. The current therapeutic strategy may improve the patient’s overall condition and in parallel may decrease the mortality rate of the current disease.