type ii pneumocytes
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Author(s):  
Manoj B. Menon ◽  
Tatiana Yakovleva ◽  
Natalia Ronkina ◽  
Abdulhadi Suwandi ◽  
Ivan Odak ◽  
...  

By crossing septin7-floxed mice with Lyz2-Cre mice carrying the Cre recombinase inserted in the Lysozyme-M (Lyz2) gene locus we aimed the specific deletion of septin7 in myeloid cells, such as monocytes, macrophages and granulocytes. Septin7flox/flox:Lyz2-Cre mice show no alterations in the myeloid compartment. Septin7-deleted macrophages (BMDMs) were isolated and analyzed. The lack of Septin7 expression was confirmed and a constitutive double-nucleation was detected in Septin7-deficient BMDMs indicating a defect in macrophage cytokinesis. However, phagocytic function of macrophages as judged by uptake of labelled E. coli particles and LPS-stimulated macrophage activation as judged by induction of TNF mRNA expression and TNF secretion were not compromised. In addition to myeloid cells, Lyz2-Cre is also active in type II pneumocytes (AT2 cells). We monitored lung adenocarcinoma formation in these mice by crossing them with the conditional knock-in Kras-LSL-G12D allele. Interestingly, we found that control mice without septin7 depletion die after 3–5 weeks, while the Septin7-deficient animals survived 11 weeks or even longer. Control mice sacrificed in the age of 4 weeks display a bronchiolo-alveolar hyperplasia with multiple adenomas, whereas the Septin7-deficient animals of the same age are normal or show only a weak multifocal brochiolo-alveolar hyperplasia. Our findings indicate an essential role of Septin7 in macrophage cytokinesis but not in macrophage function. Furthermore, septin7 seems absolutely essential for oncogenic Kras-driven lung tumorigenesis making it a potential target for anti-tumor interventions.


2021 ◽  
pp. 030098582110668
Author(s):  
Olivia M. Patania ◽  
Shiho Chiba ◽  
Peter J. Halfmann ◽  
Masato Hatta ◽  
Tadashi Maemura ◽  
...  

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019, which ranges from fatal disease in some to mild or subclinical in most affected individuals. Many recovered human patients report persistent respiratory signs; however, lung disease in post-acute infection is poorly understood. Our objective was to describe histologic lung lesions and viral loads following experimental SARS-CoV-2 infection in 11 cats. Microscopic evaluation at 3, 6, 10, or 28 days postinoculation (DPI) identified mild to moderate patchy interstitial pneumonia, bronchiolar epithelial damage, and occlusive histiocytic bronchiolitis. Based on immunohistochemistry, alveolar septal thickening was due to CD204-positive macrophages, fewer B and T lymphocytes, type II pneumocytes, and capillary proliferation with a relative dearth of fibrosis. In blood vessel endothelium, there was reactive hypertrophy or vacuolar degeneration and increased MHC II expression at all time points. Unexpectedly, one cat from the 28 DPI group had severe subacute regionally extensive lymphohistiocytic pneumonia with multifocal consolidation, vasculitis, and alveolar fibrin. Reverse transcriptase-quantitative polymerase chain reaction identified SARS-CoV-2 RNA within the lung at 3 and 6 DPI, and viral RNA was below the limit of detection at 10 and 28 DPI, suggesting that pulmonary lesions persist beyond detection of viral RNA. These findings clarify our comparative understanding of disease induced by SARS-CoV-2 and suggest that cats can serve as an informative model to study post-acute pulmonary sequelae.


2021 ◽  
Vol 8 ◽  
Author(s):  
Annaïg Bertho ◽  
Morgane Dos Santos ◽  
Sarah Braga-Cohen ◽  
Valérie Buard ◽  
Vincent Paget ◽  
...  

Lung stereotactic body radiation therapy is characterized by a reduction in target volumes and the use of severely hypofractionated schedules. Preclinical modeling became possible thanks to rodent-dedicated irradiation devices allowing accurate beam collimation and focal lung exposure. Given that a great majority of publications use single dose exposures, the question we asked in this study was as follows: in incremented preclinical models, is it worth using fractionated protocols or should we continue focusing solely on volume limitation? The left lungs of C57BL/6JRj mice were exposed to ionizing radiation using arc therapy and 3 × 3 mm beam collimation. Three-fraction schedules delivered over a period of 1 week were used with 20, 28, 40, and 50 Gy doses per fraction. Lung tissue opacification, global histological damage and the numbers of type II pneumocytes and club cells were assessed 6 months post-exposure, together with the gene expression of several lung cells and inflammation markers. Only the administration of 3 × 40 Gy or 3 × 50 Gy generated focal lung fibrosis after 6 months, with tissue opacification visible by cone beam computed tomography, tissue scarring and consolidation, decreased club cell numbers and a reactive increase in the number of type II pneumocytes. A fractionation schedule using an arc-therapy-delivered three fractions/1 week regimen with 3 × 3 mm beam requires 40 Gy per fraction for lung fibrosis to develop within 6 months, a reasonable time lapse given the mouse lifespan. A comparison with previously published laboratory data suggests that, in this focal lung irradiation configuration, administering a Biological Effective Dose ≥ 1000 Gy should be recommended to obtain lung fibrosis within 6 months. The need for such a high dose per fraction challenges the appropriateness of using preclinical highly focused fractionation schedules in mice.


Author(s):  
Andrea M. T. Kallumadyil ◽  
Tess McClenahan ◽  
Samantha De Filippis ◽  
Ananya Vungarala ◽  
Nihal Satyadev ◽  
...  

Abstract B.1.1.7 is a recently discovered variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) associated with increased transmissibility. Recent findings indicate that this variant has a propensity to infect adolescents and children at higher rates than adults. The virus gains entry into various body cells utilizing angiotensin-converting enzyme 2 (ACE-2) and basigin (CD147) as receptors. The virus mainly affects type II pneumocytes of lungs, endothelial cells, enterocytes, and renal tubular cells. It is reported to affect testes, causing testicular pain, and producing histopathological changes, as observed in some autopsies. The B.1.1.7 variant can also affect various cells in the testes. This raises a major concern regarding the long-term effects of the viral infection on spermatogenesis and highlights the pressing need for a robust database of serum samples from infected male children.


2021 ◽  
Author(s):  
Giuliana Scarpati ◽  
Daniela Baldassarre ◽  
Graziella Lacava ◽  
Filomena Oliva ◽  
Gabriele Pascale ◽  
...  

Rationale Krebs von den Lungen 6 (KL-6) is a high molecular weight mucin-like glycoprotein produced by type II pneumocytes and bronchial epithelial cells. Elevated circulating levels of KL-6 may denote disorder of the alveolar epithelial lining. Objective Aim of this study was to verify if KL-6 values may help to risk stratify and triage severe COVID-19 patients. Methods We performed a retrospective prognostic study on 110 COVID-19 ICU patients, evaluating the predictive role of KL-6 for mortality. Measurements and Main Results The study sample was divided in two groups related according to the median KL-6 value [Group A (KL-6 lower than the log-transformed median (6.73)) and Group B (KL-6 higher than the log-transformed median)]. In both linear and logistic multivariate analyses, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (P/F) was significantly and inversely related to KL-6. Death rate was higher in group B than in group A (80.3 versus 45.9%) (p<0.001), Accordingly, the Cox regression analysis showed a significant prognostic role of KL-6 on mortality in the whole sample as well as in the subgroup with SOFA lower than its median value. Conclusions At ICU admission, KL-6 serum level was significantly lower in the survivors group. Our findings shown that, in severe COVID19 patients, elevated KL-6 was strongly associated with mortality in ICU.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Duried Alwazeer ◽  
Franky Fuh-Ching Liu ◽  
Xiao Yu Wu ◽  
Tyler W. LeBaron

COVID-19 is a widespread global pandemic with nearly 185 million confirmed cases and about four million deaths. It is caused by an infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which primarily affects the alveolar type II pneumocytes. The infection induces pathological responses including increased inflammation, oxidative stress, and apoptosis. This situation results in impaired gas exchange, hypoxia, and other sequelae that lead to multisystem organ failure and death. As summarized in this article, many interventions and therapeutics have been proposed and investigated to combat the viral infection-induced inflammation and oxidative stress that contributes to the etiology and pathogenesis of COVID-19. However, these methods have not significantly improved treatment outcomes. This may partly be attributable to their inability at restoring redox and inflammatory homeostasis, for which molecular hydrogen (H2), an emerging novel medical gas, may complement. Herein, we systematically review the antioxidative, anti-inflammatory, and antiapoptotic mechanisms of H2. Its small molecular size and nonpolarity allow H2 to rapidly diffuse through cell membranes and penetrate cellular organelles. H2 has been demonstrated to suppress NF-κB inflammatory signaling and induce the Nrf2/Keap1 antioxidant pathway, as well as to improve mitochondrial function and enhance cellular bioenergetics. Many preclinical and clinical studies have demonstrated the beneficial effects of H2 in varying diseases, including COVID-19. However, the exact mechanisms, primary modes of action, and its true clinical effects remain to be delineated and verified. Accordingly, additional mechanistic and clinical research into this novel medical gas to combat COVID-19 complications is warranted.


Author(s):  
X. Sophia ◽  
C. Jayakumar ◽  
R.S. Abhilash ◽  
P.K. Magnus ◽  
K.B. Dhanush

Background: Elective cesarean section (CS) is an appropriate therapeutic modality in high risk pregnant dogs and it is scheduled following a drop in serum progesterone to less than 2ng/ml. However, a series of progesterone assays are required to confirm this drop in serum progesterone levels and this voluntary waiting period often results in foetal loss. The present study aimed to assess the innocuity of elective CS in dogs before the prepartum decline of serum progesterone, without administration of any priming agents. Methods: Elective CS was performed on an estimated day 63 of ovulation in seven high risk pregnant dogs with a serum progesterone level between 2-5 ng/ml (Group I) and maternal and neonatal outcomes were assessed in comparison with nine dogs that underwent elective CS at serum progesterone less than 2 ng/ml (Group II). Histopathological examination of lung tissue from dead neonates was performed to ascertain the presence of type II pneumocytes for assessing lung maturity. Result: Even though progesterone levels were above 2 ng/ml in dogs of Group I at the time of elective CS (3.11±0.29 ng/mL), the live birth rate was 96.97 per cent with acceptable neonatal survival. The histopathology of lung tissue from dead neonates from Group I revealed the presence of type II pneumocytes. The study suggested that elective CS in dogs could be done on day 63 after ovulation without compromising foetal lung maturity and a drop in serum progesterone level to less than 2 ng/ml was not mandatory for puppy survivability.


2021 ◽  
pp. 030098582110430
Author(s):  
Hui-Ling Yen ◽  
Sophie Valkenburg ◽  
Sin Fun Sia ◽  
Ka Tim Choy ◽  
J. S. Malik Peiris ◽  
...  

Several animal models have been developed to study the pathophysiology of SARS-CoV-2 infection and to evaluate vaccines and therapeutic agents for this emerging disease. Similar to infection with SARS-CoV-1, infection of Syrian hamsters with SARS-CoV-2 results in moderate respiratory disease involving the airways and lung parenchyma but does not lead to increased mortality. Using a combination of immunohistochemistry and transmission electron microscopy, we showed that the epithelium of the conducting airways of hamsters was the primary target for viral infection within the first 5 days of infection, with little evidence of productive infection of pneumocytes. At 6 days postinfection, antigen was cleared but parenchymal damage persisted, and the major pathological changes resolved by day 14. These findings are similar to those previously reported for hamsters with SARS-CoV-1 infection. In contrast, infection of K18-hACE2 transgenic mice resulted in pneumocyte damage, with viral particles and replication complexes in both type I and type II pneumocytes together with the presence of convoluted or cubic membranes; however, there was no evidence of virus replication in the conducting airways. The Syrian hamster is a useful model for the study of SARS-CoV-2 transmission and vaccination strategies, whereas infection of the K18-hCE2 transgenic mouse results in lethal disease with fatal neuroinvasion but with sparing of conducting airways.


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