Pollution des captages d'eau brute de Bretagne par les matières organiques. Rapport de synthèse : tableau de bord de la pollution, causes possibles, recommandations

A l'échelle de la Bretagne, 64 prises d'eau sur 118 connaissaient en 2002 des dépassements du seuil réglementaire maximal autorisé de concentration en matière organique

Pollution des rivières de Bretagne par les matières organiques. Etat des lieux, trajectoires d'évolution et causes possibles

Nous avons voulu comparer la charge actuelle des BV bretons en MO avec celles d'autres BV dans le monde, situés dans des contextes pédo-climatiques semblables. Cette comparaison montre que la concentration moyenne annuelle calculée à l'exutoire du BV de Kervidy-Naizin entre 1999-2003 est comparable aux concentrations trouvés dans des bassins versants anglais et correspond aux valeurs anticipées à partir de la teneur en carbone organique des sols du bassin. Par contre, les concentrations mesurées actuellement au Léguer sont très supérieures aux valeurs attendues compte tenu du contexte pédo-climatique de ce bassin. Le différentiel est d'un facteur 2.5. En d'autres termes, pour faire rentrer le BV du Léguer dans la "norme" propre à son contexte "naturel" il faut ramener sa concentration moyenne annuelle à celle qu'il affichait en 1979. Ce résultat nous incline à penser (a) que les eaux du Léguer véhiculent en 2003 des quantités de MO anormalement élevées et (b) que les mécanismes ayant conduit à cette anormalité se sont probablement mis en place vers la fin des années 1980. La nature exacte de ceux-ci reste à élucider. Une partie de la réponse devrait être fournie par les analyses moléculaires en cours sur ce BV

Commensal Microbiota Effects on Craniofacial Skeletal Growth and Morphology

ABSTRACT Microbes colonize anatomical sites in health to form commensal microbial communities (e.g., commensal gut microbiota, commensal skin microbiota, commensal oral microbiota). Commensal microbiota has indirect effects on host growth and maturation through interactions with the host immune system. The commensal microbiota was recently introduced as a novel regulator of skeletal growth and morphology at noncraniofacial sites. Further, we and others have shown that commensal gut microbes, such as segmented filamentous bacteria (SFB), contribute to noncraniofacial skeletal growth and maturation. However, commensal microbiota effects on craniofacial skeletal growth and morphology are unclear. To determine the commensal microbiota's role in craniofacial skeletal growth and morphology, we performed craniometric and bone mineral density analyses on skulls from 9‐week‐old female C57BL/6T germ‐free (GF) mice (no microbes), excluded‐flora (EF) specific‐pathogen‐free mice (commensal microbiota), and murine‐pathogen‐free (MPF) specific‐pathogen‐free mice (commensal microbiota with SFB). Investigations comparing EF and GF mice revealed that commensal microbiota impacted the size and shape of the craniofacial skeleton. EF versus GF mice exhibited an elongated gross skull length. Cranial bone length analyses normalized to skull length showed that EF versus GF mice had enhanced frontal bone length and reduced cranial base length. The shortened cranial base in EF mice was attributed to decreased presphenoid, basisphenoid, and basioccipital bone lengths. Investigations comparing MPF mice and EF mice demonstrated that commensal gut microbes played a role in craniofacial skeletal morphology. Cranial bone length analyses normalized to skull length showed that MPF versus EF mice had reduced frontal bone length and increased cranial base length. The elongated cranial base in MPF mice was due to enhanced presphenoid bone length. This work, which introduces the commensal microbiota as a contributor to craniofacial skeletal growth, underscores that noninvasive interventions in the gut microbiome could potentially be employed to modify craniofacial skeletal morphology. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research

The midregion, nuclear localization sequence, and C terminus of PTHrP regulate skeletal development, hematopoiesis, and survival in mice

The functions of parathyroid hormone-related protein (PTHrP) on morphogenesis, cell proliferation, apoptosis, and calcium homeostasis have been attributed to its N terminus. Evidence suggests that many of these effects are not mediated by the N terminus but by the midregion, a nuclear localization sequence (NLS), and C terminus of the protein. A knock-in mouse lacking the midregion, NLS, and C terminus of PTHrP (PthrpΔ/Δ) was developed. PthrpΔ/Δ mice had craniofacial dysplasia, chondrodysplasia, and kyphosis, with most mice dying by d 5 of age. In bone, there were fewer chondrocytes and osteoblasts per area, bone mass was decreased, and the marrow was less cellular, with erythroid hypoplasia. Cellular proliferation was impaired, and apoptosis was increased. Runx2, Ocn, Sox9, Crtl1, β-catenin, Runx1, ephrin B2, cyclin D1, and Gata1 were underexpressed while P16/Ink4a, P21, GSK-3β, Il-6, Ffg3, and Ihh were overexpressed. Mammary gland development was aberrant, and energy metabolism was deregulated. These results establish that the midregion, NLS, and C terminus of PTHrP are crucial for the commitment of osteogenic and hematopoietic precursors to their lineages, and for survival, and many of the effects of PTHrP on development are not mediated by its N terminus. The down-regulation of Runx1, Runx2, and Sox9 indicates that PTHrP is a modulator of transcriptional activation during stem cell commitment. Toribio, R. E., Brown, H. A., Novince, C. M., Marlow, B. Hernon, K., Lanigan, L. G., Hildreth III, B. E., Werbeck, J. L., Shu, S. T., Lorch, G., Carlton, M., Foley, J., Boyaka, P., McCauley, L. K., Rosol, T. J. The midregion, nuclear localization sequence, and C terminus of PTHrP regulate skeletal development, hematopoiesis, and survival in mice

Acid bone lysate activates TGFβ signalling in human oral fibroblasts

Abstract Demineralized bone matrix is a widely used allograft from which not only the inorganic mineral but also embedded growth factors are removed by hydrochloric acid (HCl). The cellular response to the growth factors released during the preparation of demineralized bone matrix, however, has not been studied. Here we investigated the in vitro impact of acid bone lysate (ABL) prepared from porcine cortical bone chips on oral fibroblasts. Proteomic analysis of ABL revealed a large spectrum of bone-derived proteins including TGF-β1. Whole genome microarrays and RT-PCR together with the pharmacologic blocking of TGF-β receptor type I kinase with SB431542 showed that ABL activates the TGF-β target genes interleukin 11, proteoglycan 4, and NADPH oxidase 4. Interleukin 11 expression was confirmed at the protein level by ELISA. Immunofluorescence and Western blot showed the nuclear localization of Smad2/3 and increased phosphorylation of Smad3 with ABL, respectively. This effect was independent of whether ABL was prepared from mandible, calvaria or tibia. These results demonstrate that TGF-β is a major growth factor that is removed upon the preparation of demineralized bone matrix