The Journey of SCAPs (Stem Cells from Apical Papilla), from Their Native Tissue to Grafting: Impact of Oxygen Concentration

Tissue engineering strategies aim at characterizing and at optimizing the cellular component that is combined with biomaterials, for improved tissue regeneration. Here, we present the immunoMap of apical papilla, the native tissue from which SCAPs are derived. We characterized stem cell niches that correspond to a minority population of cells expressing Mesenchymal stromal/Stem Cell (CD90, CD105, CD146) and stemness (SSEA4 and CD49f) markers as well as endothelial cell markers (VWF, CD31). Based on the colocalization of TKS5 and cortactin markers, we detected migration-associated organelles, podosomes-like structures, in specific regions and, for the first time, in association with stem cell niches in normal tissue. From six healthy teenager volunteers, each with two teeth, we derived twelve cell banks, isolated and amplified under 21 or 3% O2. We confirmed a proliferative advantage of all banks when cultured under 3% versus 21% O2. Interestingly, telomerase activity was similar to that of the highly proliferative hiPSC cell line, but unrelated to O2 concentration. Finally, SCAPs embedded in a thixotropic hydrogel and implanted subcutaneously in immunodeficient mice were protected from cell death with a slightly greater advantage for cells preconditioned at 3% O2

Estimation of the prevalence of lymphoedema/chronic oedema in acute hospital in-patients

Background: To estimate the prevalence of lymphoedema/chronic oedema and wounds in acute hospital in-patients in 5 different countries. Method: A point-prevalence study was carried out during working day periods in six general hospitals in four countries (Denmark, France, United Kingdom, Australia) and one hospital oncology in-patient unit in one other country (Ireland). The study used validated clinical tools for the assessment and collection of data. Data were collected by expert clinicians through interviews and physical examination of the patients present in the wards. Results: A total of 1905 patients could be included and investigated among the 3041 total bed occupancy in the seven hospitals. Lymphoedema/chronic oedema was present in 723 of them (38%). Main risk factors associated with chronic oedema were age, morbid obesity and heart failure as well as chair bound immobility and neurological deficiency. History of cellulitis was frequent in patients with chronic oedema and wounds (24.8%), chronic oedema alone (14.1%) as compared to the 1.5% prevalence in patients without chronic oedema. Conclusion: Lymphoedema/chronic oedema is very frequent in patients hospitalized in hospital acute wards. It is strongly associated with obesity, venous insufficiency and heart failure. Our results strongly suggest a hidden health care burden and cost linked to chronic oedema independently of chronic wounds

La mobilité vélo et le potentiel cyclable. In : La mobilité urbaine, questions de recherche, Publication eramob/PCI-mob

La mobilité à vélo a changé de profil dans les années 2000 en France, en s’implantant dans les villes. Quels sont les caractéristiques et les nouveaux territoires de cette mobilité ? Le niveau de pratique reste très en-deçà de ce qu’il est dans certaines villes étrangères. Nous verrons l’exemple de Gand. Or, le potentiel des déplacements qui peuvent être réalisés à vélo est très élevé, comme le montre le cas de la région de Lille. La question qui se pose est donc : quelles sont les politiques nécessaires pour développer le vélo et lever les freins à sa pratique

Parallel biotransformation of tetrabromobisphenol A in Xenopus laevis and mammals: Xenopus as a model for endocrine perturbation studies.

The flame retardant tetrabromobisphenol A (TBBPA) is a high production flame retardant that interferes with thyroid hormone (TH) signaling. Despite its rapid metabolism in mammals, TBBPA is found in significant amounts in different tissues. Such findings highlight first a need to better understand the effects of TBBPA and its metabolites and second the need to develop models to address these questions experimentally. We used Xenopus laevis tadpoles to follow radiolabeled (14)C-TBBPA uptake and metabolism. Extensive and rapid uptake of radioactivity was observed, tadpoles metabolizing > 94% of (14)C-TBBPA within 8 h. Four metabolites were identified in water and tadpole extracts: TBBPA-glucuronide, TBBPA-glucuronide-sulfate, TBBPA-sulfate, and TBBPA-disulfate. These metabolites are identical to the TBBPA conjugates characterized in mammals, including humans. Most radioactivity (> 75%) was associated with sulfated conjugates. The antithyroid effects of TBBPA and the metabolites were compared using two in vivo measures: tadpole morphology and an in vivo tadpole TH reporter gene assay. Only TBBPA, and not the sulfated metabolites, disrupted thyroid signaling. Moreover, TBBPA treatment did not affect expression of phase II enzymes involved in TH metabolism, suggesting that the antithyroid effects of TBBPA are not due to indirect effects on TH metabolism. Finally, we show that only the parent TBBPA inhibits T3-induced transactivation in cells expressing human, zebrafish, or X. laevis TH receptor, TRα. We conclude, first, that perturbation of thyroid signaling by TBBPA is likely due to rapid direct action of the parent compound, and second, that Xenopus is an excellent vertebrate model for biotransformation studies, displaying homologous pathways to mammals

The Journey of SCAPs (Stem Cells from Apical Papilla), from Their Native Tissue to Grafting: Impact of Oxygen Concentration

Tissue engineering strategies aim at characterizing and at optimizing the cellular component that is combined with biomaterials, for improved tissue regeneration. Here, we present the immunoMap of apical papilla, the native tissue from which SCAPs are derived. We characterized stem cell niches that correspond to a minority population of cells expressing Mesenchymal stromal/Stem Cell (CD90, CD105, CD146) and stemness (SSEA4 and CD49f) markers as well as endothelial cell markers (VWF, CD31). Based on the colocalization of TKS5 and cortactin markers, we detected migration-associated organelles, podosomes-like structures, in specific regions and, for the first time, in association with stem cell niches in normal tissue. From six healthy teenager volunteers, each with two teeth, we derived twelve cell banks, isolated and amplified under 21 or 3% O2. We confirmed a proliferative advantage of all banks when cultured under 3% versus 21% O2. Interestingly, telomerase activity was similar to that of the highly proliferative hiPSC cell line, but unrelated to O2 concentration. Finally, SCAPs embedded in a thixotropic hydrogel and implanted subcutaneously in immunodeficient mice were protected from cell death with a slightly greater advantage for cells preconditioned at 3% O2