Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal;
Published: February 2018
AI Article Synopsis
Article Abstract
Despite the well-documented effect of castration in thymic regeneration, the singular contribution of the bone marrow (BM) versus the thymus to this process remains unclear. The chief role of IL-7 in pre- and intrathymic stages of T lymphopoiesis led us to investigate the impact of disrupting this cytokine during thymic rebound induced by androgen blockade. We found that castration promoted thymopoiesis in young and aged wild-type mice. In contrast, only young germline IL-7-deficient ( ) mice consistently augmented thymopoiesis after castration. The increase in T cell production was accompanied by the expansion of the sparse medullary thymic epithelial cell and the peripheral T cell compartment in young mice. In contrast to young and wild-type mice, the poor thymic response of aged mice after castration was associated with a defect in the expansion of BM hematopoietic progenitors. These findings suggest that BM-derived T cell precursors contribute to thymic rebound driven by androgen blockade. To assess the role of IL-7 within the thymus, we generated mice with conditional deletion of IL-7 ( conditional knockout [cKO]) in thymic epithelial cells. As expected, cKO mice presented a profound defect in T cell development while maintaining an intact BM hematopoietic compartment across life. Unlike mice, castration promoted the expansion of BM precursors and enhanced thymic activity in cKO mice independently of age. Our findings suggest that the mobilization of BM precursors acts as a prime catalyst of castration-driven thymopoiesis.
The thymus is the central organ involved with T-cell development and the production of naïve T cells. During normal aging, the thymus undergoes marked involution, reducing naïve T-cell output and resulting in a predominance of long-lived memory T cells in the periphery. Outside of aging, systemic stress responses that induce corticosteroids (CS), or other insults such as radiation exposure, induce thymocyte apoptosis, resulting in a transient acute thymic involution with subsequent recovery occurring after cessation of the stimulus.
* After one week of DOX treatment, there was a significant reduction in thymus weight and notable alterations in T cell populations, indicating early immune system effects, along with changes in gene expression linked to immune function and senescence.
* Five weeks post-treatment, some recovery was observed with an increase in thymus weight and shifts in T cell subsets, but also revealed decreases in specific memory T cells, pointing towards long-term changes in immune response following DOX exposure.
Conventional immunosuppressants are not effective for treating asthma related to Eosinophilic Granulomatosis with Polyangiitis (EGPA).
Tezepelumab, a monoclonal antibody targeting thymic stromal lymphopoietin (TSLP), has shown promise in improving asthma symptoms in patients with severe refractory EGPA-related asthma.
Despite improvements in symptoms and asthma control, there are concerns about potential rebound eosinophilia and related complications due to TSLP inhibition, as observed in similar treatments.
Mediastinal tumours are a diverse group of growths originating from structures in or near the mediastinum, which has distinct anatomical compartments: prevascular (anterior), visceral (middle), and paravertebral (posterior).
Common benign tumours in the anterior mediastinum include thymic cysts, various types of thymic hyperplasia, and other benign thymic tumours, while the middle and posterior compartments feature conditions like pericardial cysts and neurogenic tumours.
The review emphasizes the importance of understanding histology, epidemiological data, and clinical aspects for accurately diagnosing and managing benign mediastinal lesions, particularly those involving the thymus.
Background: To investigate the potential of radiomic features and dual-source dual-energy CT (DECT) parameters in differentiating between benign and malignant mediastinal masses and predicting patient outcomes.
Methods: In this retrospective study, we analysed data from 90 patients (38 females, mean age 51 ± 25 years) with confirmed mediastinal masses who underwent contrast-enhanced DECT. Attenuation, radiomic features and DECT-derived imaging parameters were evaluated by two experienced readers.
