ABSTRACT
Adult lungs present high cellular plasticity against stress and injury, mobilizing stem/progenitor populations from conducting airways to maintain tissue homeostasis and gas exchange in alveolar spaces. With aging, pulmonary functional and structural deterioration occurs, mainly in pathological conditions, which is associated with impaired stem cell activity and increased senescence in mice. However, the impact of these processes underlying lung physiopathology in relation to aging has not been explored in humans. In this work, we analyzed stem cell (SOX2, p63, KRT5), senescence (p16INK4A, p21CIP, Lamin B1) and proliferative (Ki67) markers in lung samples from young and aged individuals, with and without pulmonary pathology. We identified a reduction in SOX2+ cells but not p63+ and KRT5+ basal cells in small airways with aging. In alveoli, we revealed the presence of triple SOX2+, p63+ and KRT5+ cells specifically in aged individuals diagnosed with pulmonary pathologies. Notably, p63+ and KRT5+ basal stem cells displayed colocalization with p16INK4A and p21CIP, as well as with low Lamin B1 staining in alveoli. Further studies revealed that senescence and proliferation markers were mutually exclusive in stem cells with a higher percentage colocalizing with senescence markers. These results provide new evidence of the activity of p63+/KRT5+ stem cells on human lung regeneration and point out that regeneration machinery in human lung is activated under stress due to aging, but fails to repair in pathological cases, as stem cells would likely become senescent.
ABSTRACT
A 68-year-old man presented to the Emergency Department with undifferentiated shock. During the three days prior, he experienced a non-specific viral-like illness. On examination his blood pressure was 70/40 mm Hg with cool, clammy, and mottled extremities and flat neck veins. Laboratory investigations revealed a positive influenza B screen alongside elevated hemoglobin and hematocrit. Following aggressive fluid resuscitation his blood pressure had marginally improved and he was transferred to the intensive care unit (ICU). Vasopressor support with cautious fluid resuscitation continued and at 7- and 10-h following presentation, serum albumin levels were extremely low. Idiopathic systemic capillary leak syndrome triggered by influenza B infection was diagnosed. Following a 9-day ICU stay the patient made a complete recovery and remains stable on intravenous immunoglobulin therapy. This case highlights the importance judicious fluid resuscitation and serum albumin levels when confronted with refractory shock.
ABSTRACT
BACKGROUND: In recent years, three-dimensional (3D)-printing of tissue-engineered cartilaginous scaffolds is intended to close the surgical gap and provide bio-printed tissue designed to fit the specific geometric and functional requirements of each cartilage defect, avoiding donor site morbidity and offering a personalizing therapy. METHODS: To investigate the role of 3D-bioprinting scaffolding for nasal cartilage defects repair a systematic review of the electronic databases for 3D-Bioprinting articles pertaining to nasal cartilage bio-modelling was performed. The primary focus was to investigate cellular source, type of scaffold utilization, biochemical evaluation, histological analysis, in-vitro study, in-vivo study, animal model used, length of research, and placement of experimental construct and translational investigation. RESULTS: From 1011 publications, 16 studies were kept for analysis. About cellular sources described, most studies used primary chondrocyte cultures. The cartilage used for cell isolation was mostly nasal septum. The most common biomaterial used for scaffold creation was polycaprolactone alone or in combination. About mechanical evaluation, we found a high heterogeneity, making it difficult to extract any solid conclusion. Regarding biological and histological characteristics of each scaffold, we found that the expression of collagen type I, collagen Type II and other ECM components were the most common patterns evaluated through immunohistochemistry on in-vitro and in-vivo studies. Only two studies made an orthotopic placement of the scaffolds. However, in none of the studies analyzed, the scaffold was placed in a subperichondrial pocket to rigorously simulate the cartilage environment. In contrast, scaffolds were implanted in a subcutaneous plane in almost all of the studies included. CONCLUSION: The role of 3D-bioprinting scaffolding for nasal cartilage defects repair is growing field. Despite the amount of information collected in the last years and the first surgical applications described recently in humans. Further investigations are needed due to the heterogeneity on mechanical evaluation parameters, the high level of heterotopic scaffold implantation and the need for quantitative histological data.
Subject(s)
Bioprinting , Animals , Chondrocytes , Humans , Nasal Cartilages/surgery , Printing, Three-Dimensional , Tissue ScaffoldsABSTRACT
The presence and functional role of T cell infiltration in human brain parenchyma with normal aging and neurodegeneration is still under intense debate. Recently, CD8+ cells have been shown to infiltrate the subventricular zone in humans and mice with a deleterious effect on neural stem cells. However, to which extent T cell infiltration in humans also occurs in other regions such as cortical areas and, especially, white matter (WM) has not yet been addressed. In this work, we report a low-grade infiltration of T cells (CD3+, CD4+ and CD8+) in the WM of aged individuals that is also observed at similar levels in patients with neurodegenerative disorders (Alzheimer´s disease). In particular, CD3+ and CD8+ cells were increased in perivascular and parenchymal WM and cortical regions (enthorinal cortex). These results reveal that T cell infiltration in brain parenchyma occurs with physiological and pathological aging in several regions, but it seems to be lower than in the subventricular zone neurogenic niche.
