Bridges of biomaterials promote nigrostriatal pathway regeneration

[EN] Repair of central nervous system (CNS) lesions is difficulted by the lack of ability of central axons to regrow, and the blocking by the brain astrocytes to axonal entry. We hypothesized that by using bridges made of porous biomaterial and permissive olfactory ensheathing glia (OEG), we could provide a scaffold to permit restoration of white matter tracts. We implanted porous polycaprolactone (PCL) bridges between the substantia nigra and the striatum in rats, both with and without OEG. We compared the number of tyrosine-hydroxylase positive (TH+) fibers crossing the striatal-graft interface, and the astrocytic and microglial reaction around the grafts, between animals grafted with and without OEG. Although TH+ fibers were found inside the grafts made of PCL alone, there was a greater fiber density inside the graft and at the striatal-graft interface when OEG was cografted. Also, there was less astrocytic and microglial reaction in those animals. These results show that these PCL grafts are able to promote axonal growth along the nigrostriatal pathway, and that cografting of OEG markedly enhances axonal entry inside the grafts, growth within them, and re-entry of axons into the CNS. These results may have implications in the treatment of diseases such as Parkinson's and others associated with lesions of central white matter tracts.Contract grant sponsor: Regional Government Health Department (Conselleria de Sanitat, Generalitat Valenciana) and Carlos III Health Institute of the Ministry of Health and Consumer Affairs (Spain) (Regenerative Medicine Programme) Contract grant sponsor: Spanish ministry of Education and Science; contract grant number: MAT 2006-13554-C02-02 Contract grant sponsor: Red de Terapia Celular TERCEL (RETICS), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovacion (ISCIII); contract grant number: RD12/0019/0010 (to J.A.) Contract grant sponsor: Spanish Science & Innovation Ministery; contract grant number: MAT2008-06434 (to M.M.P.) Contract grant sponsor: "Convenio de Colaboracion para la Investigacion Basica y Traslacional en Medicina Regenerativa," Instituto Nacional de Salud Carlos III, the Conselleria de Sanidad of the Generalitat Valenciana, and the Foundation Centro de Investigacion Principe FelipeGómez Pinedo, U.; Sanchez-Rojas, L.; Vidueira, S.; Sancho, FJ.; Martínez-Ramos, C.; Lebourg, M.; Monleón Pradas, M.... (2019). Bridges of biomaterials promote nigrostriatal pathway regeneration. Journal of Biomedical Materials Research Part B Applied Biomaterials. 107(1):190-196. https://doi.org/10.1002/jbm.b.34110S1901961071Pekny, M., Wilhelmsson, U., & Pekna, M. (2014). The dual role of astrocyte activation and reactive gliosis. Neuroscience Letters, 565, 30-38. doi:10.1016/j.neulet.2013.12.071Bliss, T. M., Andres, R. H., & Steinberg, G. K. (2010). Optimizing the success of cell transplantation therapy for stroke. Neurobiology of Disease, 37(2), 275-283. doi:10.1016/j.nbd.2009.10.003Tam, R. Y., Fuehrmann, T., Mitrousis, N., & Shoichet, M. S. (2013). Regenerative Therapies for Central Nervous System Diseases: a Biomaterials Approach. Neuropsychopharmacology, 39(1), 169-188. doi:10.1038/npp.2013.237Skop, N. B., Calderon, F., Cho, C. H., Gandhi, C. D., & Levison, S. W. (2014). Improvements in biomaterial matrices for neural precursor cell transplantation. Molecular and Cellular Therapies, 2(1), 19. doi:10.1186/2052-8426-2-19Yasuhara, T., Kameda, M., Sasaki, T., Tajiri, N., & Date, I. (2017). Cell Therapy for Parkinson’s Disease. Cell Transplantation, 26(9), 1551-1559. doi:10.1177/0963689717735411Orive, G., Anitua, E., Pedraz, J. L., & Emerich, D. F. (2009). Biomaterials for promoting brain protection, repair and regeneration. Nature Reviews Neuroscience, 10(9), 682-692. doi:10.1038/nrn2685Walker, P. A., Aroom, K. R., Jimenez, F., Shah, S. K., Harting, M. T., Gill, B. S., & Cox, C. S. (2009). Advances in Progenitor Cell Therapy Using Scaffolding Constructs for Central Nervous System Injury. Stem Cell Reviews and Reports, 5(3), 283-300. doi:10.1007/s12015-009-9081-1Zhong, Y., & Bellamkonda, R. V. (2008). Biomaterials for the central nervous system. Journal of The Royal Society Interface, 5(26), 957-975. doi:10.1098/rsif.2008.0071Pérez‐GarnezM BarciaJA Gómez‐PinedoU Monleón‐PradasM Vallés‐LluchA.Materials for Central Nervous System Tissue Engineering Cells and Biomaterials in Regenerative Medicine. InTech;2014. Chap 7.Sinha, V. R., Bansal, K., Kaushik, R., Kumria, R., & Trehan, A. (2004). Poly-ϵ-caprolactone microspheres and nanospheres: an overview. International Journal of Pharmaceutics, 278(1), 1-23. doi:10.1016/j.ijpharm.2004.01.044Raisman, G. (2001). Olfactory ensheathing cells — another miracle cure for spinal cord injury? Nature Reviews Neuroscience, 2(5), 369-375. doi:10.1038/35072576Raisman, G., & Li, Y. (2007). Repair of neural pathways by olfactory ensheathing cells. Nature Reviews Neuroscience, 8(4), 312-319. doi:10.1038/nrn2099Fairless, R., & Barnett, S. C. (2005). Olfactory ensheathing cells: their role in central nervous system repair. The International Journal of Biochemistry & Cell Biology, 37(4), 693-699. doi:10.1016/j.biocel.2004.10.010Collins, A., Li, D., Mcmahon, S. B., Raisman, G., & Li, Y. (2017). Transplantation of Cultured Olfactory Bulb Cells Prevents Abnormal Sensory Responses during Recovery from Dorsal Root Avulsion in the Rat. Cell Transplantation, 26(5), 913-924. doi:10.3727/096368917x695353Navarro, X., Valero, A., Gudi�o, G., For�s, J., Rodr�guez, F. J., Verd�, E., … Nieto-Sampedro, M. (1999). Ensheathing glia transplants promote dorsal root regeneration and spinal reflex restitution after multiple lumbar rhizotomy. Annals of Neurology, 45(2), 207-215. doi:10.1002/1531-8249(199902)45:23.0.co;2-kGómez-Pinedo, U., Félez, M. C., Sancho-Bielsa, F. J., Vidueira, S., Cabanes, C., Soriano, M., … Barcia, J. A. (2008). Improved technique for stereotactic placement of nerve grafts between two locations inside the rat brain. Journal of Neuroscience Methods, 174(2), 194-201. doi:10.1016/j.jneumeth.2008.07.008HowardCV ReedMG.Unbiased Stereology: Three‐Dimensional Measurement in Microscopy. Oxford: Bioimaging Group;1998.Collier, T. J., & Springer, J. E. (1991). Co-grafts of embryonic dopamine neurons and adult sciatic nerve into the denervated striatum enhance behavioral and morphological recovery in rats. Experimental Neurology, 114(3), 343-350. doi:10.1016/0014-4886(91)90160-eBourke, J. L., Coleman, H. A., Pham, V., Forsythe, J. S., & Parkington, H. C. (2014). Neuronal Electrophysiological Function and Control of Neurite Outgrowth on Electrospun Polymer Nanofibers Are Cell Type Dependent. Tissue Engineering Part A, 20(5-6), 1089-1095. doi:10.1089/ten.tea.2013.0295Nga, V. D. W., Lim, J., Choy, D. K. S., Nyein, M. A., Lu, J., Chou, N., … Teoh, S.-H. (2015). Effects of Polycaprolactone-Based Scaffolds on the Blood–Brain Barrier and Cerebral Inflammation. Tissue Engineering Part A, 21(3-4), 647-653. doi:10.1089/ten.tea.2013.0779Pérez-Garnés, M., Martínez-Ramos, C., Barcia, J. A., Escobar Ivirico, J. L., Gómez-Pinedo, U., Vallés-Lluch, A., & Monleón Pradas, M. (2012). One-Dimensional Migration of Olfactory Ensheathing Cells on Synthetic Materials: Experimental and Numerical Characterization. Cell Biochemistry and Biophysics, 65(1), 21-36. doi:10.1007/s12013-012-9399-1Diban, N., Ramos-Vivas, J., Remuzgo-Martinez, S., Ortiz, I., & Urtiaga, A. (2015). Poly(ε-caprolactone) Films with Favourable Properties for Neural Cell Growth. Current Topics in Medicinal Chemistry, 14(23), 2743-2749. doi:10.2174/156802661466614121515393

Hydrolytic and enzymatic degradation of a poly(å-caprolactone) network

“NOTICE: this is the author’s version of a work that was accepted for publication in Polymer Degradation and Stability. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Polymer Degradation and Stability, [Volume 97, Issue 8, August 2012, Pages 1241–1248] DOI 10.1016/j.polymdegradstab.2012.05.038Long-term hydrolytic and enzymatic degradation profiles of poly(å-caprolactone) (PCL) networks were obtained. The hydrolytic degradation studies were performed in water and phosphate buffer solution (PBS) for 65 weeks. In this case, the degradation rate of PCL networks was faster than previous results in the literature on linear PCL, reaching a weight loss of around 20% in 60 weeks after immersing the samples either in water or in PBS conditions. The enzymatic degradation rate in Pseudomonas Lipase for 14 weeks was also studied, with the conclusion that the degradation profile of PCL networks is lower than for linear PCL, also reaching a 20% weight loss. The weight lost, degree of swelling, and calorimetric and mechanical properties were obtained as a function of degradation time. Furthermore, the morphological changes in the samples were studied carefully through electron microscopy and crystal size through X-ray diffraction. The changes in some properties over the degradation period such as crystallinity, crystal size and Young¿s modulus were smaller in the case of enzymatic studies, highlighting differences in the degradation mechanism in the two studies, hydrolytic and enzymatic.The authors would like to acknowledge the support of the Spanish Ministry of Science and Education through the DPI2010-20399-004-03 project. JM Meseguer-Duenas and A Vidaurre also would like to acknowledge the support of the CIBER-BBN, an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. The translation of this paper was funded by the Universidad Politecnica de Valencia, SpainCastilla Cortázar, MIC.; Más Estellés, J.; Meseguer Dueñas, JM.; Escobar Ivirico, JL.; Marí Soucase, B.; Vidaurre, A. (2012). Hydrolytic and enzymatic degradation of a poly(å-caprolactone) network. Polymer Degradation and Stability. 97(8):1241-1248. https://doi.org/10.1016/j.polymdegradstab.2012.05.038S1241124897

Towards a standard typology of endogenous landslide seismic sources

The objective of this work is to propose a standard classification of seismic signals generated by gravitational processes and detected at close distances (&lt;1&thinsp;km). We review the studies where seismic instruments have been installed on unstable slopes and discuss the choice of the seismic instruments and the network geometries. Seismic observations acquired at 13 unstable slopes are analyzed in order to construct the proposed typology. The selected slopes are affected by various landslide types (slide, fall, topple and flow) triggered in various material (from unconsolidated soils to consolidated rocks). We investigate high-frequency bands (&gt;1&thinsp;Hz) where most of the seismic energy is recorded at the 1&thinsp;km sensor to source distances. Several signal properties (duration, spectral content and spectrogram shape) are used to describe the sources. We observe that similar gravitational processes generate similar signals at different slopes. Three main classes can be differentiated mainly from the length of the signals, the number of peaks and the duration of the autocorrelation. The classes are the “slopequake” class, which corresponds to sources potentially occurring within the landslide body; the “rockfall” class, which corresponds to signals generated by rock block impacts; and the “granular flow” class, which corresponds to signals generated by wet or dry debris/rock flows. Subclasses are further proposed to differentiate specific signal properties (frequency content, resonance, precursory signal). The signal properties of each class and subclass are described and several signals of the same class recorded at different slopes are presented. Their potential origins are discussed. The typology aims to serve as a standard for further comparisons of the endogenous microseismicity recorded on landslides.</p

Spontaneous Locomotor-activity of Drosophila-melanogaster Flies At Various Gravity Levels (0 G, 1 G, 1.8 G) During Parabolic Flights

The spontaneous locomotor activity of young, middle-aged and old Drosophila melanogaster of both sexes has been videorecorded during three parabolic flights separated by one-day intervals. Fast shifts between 0 g, 1 g and 1.8 g phases are obtained during parabolic flights. Results showed that the activity scores were higher at 0 g during the first flight, but that this effect of microgravity was erased during the two next flights. It may be concluded that flies showed a transient form of reactivity to a new environment, i.e, to repeated rapid variations of gravity levels

Intérêt de différents réactifs d'extraction chimique pour l'évaluation de la biodisponibilité des métaux en traces du sol

L’évaluation de la biodisponibilité des métaux en traces du sol intéresse deux grands domaines d’application : d’une part, le diagnostic de fertilité chimique basé sur l’établissement de seuils de carence, employé depuis plusieurs décennies dans différents pays ; d’autre part, l’estimation du risque de phytotoxicité ou de contamination de la chaîne alimentaire qu’entraîne la pollution du sol par les éléments en traces. Dans ce cas, très peu de pays sont allés jusqu’à l’élaboration de références de diagnostic. Afin de guider le choix d’une méthode d’extraction chimique pour permettre l’ébauche de telles références en France, une synthèse bibliographique a été entreprise. Elle reprend les principaux résultats obtenus depuis les vingt dernières années concernant l’évaluation de la biodisponibilité de Cd, Cu, Zn, Pb, Cr et Ni. De cette étude, il ressort que les solutions salines non tamponnées semblent les mieux adaptées à l’estimation rapide du transfert des éléments du sol aux végétaux et à la mise au point de valeurs guides permettant de statuer quant aux risques de toxicité susceptibles d’être engendrés par des sites pollués.The prediction of soil trace metal bioavailability using extractions has two direct applications: i) evaluation of soil chemical fertility and nutrient deficiency, as has been used widely in different countries for many years; and ii) risk assessment of phytotoxicity and contamination of the food chain induced by polluted soils. In this latter case, few countries have defined guide values. In order to choose one of the extraction methods proposed in the literature, and then define such references for France, a review of research concerning the chemical estimation of Cd, Cu, Zn, Ni, Cr and Pb plant uptake in the last twenty years was undertaken. In conclusion, the use of unbuffered salt solutions seems to be the most suitable way to i) estimate trace element transfert from polluted soil to plant and ii) define guide values for risk assessment

Optical properties of chromophoric dissolved organic matter during a phytoplankton bloom. Implication for DOC estimates from CDOM absorption

Coastal waters of the English Channel and the North Sea are affected by a massive spring phytoplankton bloom event of the prymnesiophyte Phaeocystis globosa every year. The impact of this bloom on DOM dynamics in coastal waters of the western English Channel was investigated through a 45 d long mesocosm experiment and field survey (2012-2014). Our results highlight that, over short time scales, marine production of DOM mostly affects CDOM absorption properties in the UV domain. Specifically, it has been evidenced that the a(cdom) spectral slope between 320 nm and 412 nm (S320-412) can be used as a relevant indicator of the DOM marine origin. The presence of a strong linear relationship between S320-412 and the DOC specific absorption coefficient in phytoplankton bloom conditions reveals that this optical parameter provides complementary information to those obtained from the spectral slope between 275 nm and 295 nm, S275-295 which has been recently described as a relevant tracer of the terrestrial DOM and a good descriptor of the specific absorption coefficient of dissolved organic carbon variability in the confining river-influenced ocean margins. This study has further demonstrated that the joint use of S275-295 and S320-412 significantly improves the estimation DOC-specific absorption coefficient in the presence of varying contribution of marine and terrestrial DOM. While such bands are still not available on ocean color sensors, this methodology represents a valuable tool for estimating DOC concentration from CDOM absorption measurements from in situ data obtained from classical discrete measurements or from autonomous platforms equipped with adapted spectrophotometer

Frequency and triggering of small-scale submarine landslides on decadal timescales: Analysis of 4D bathymetric data from the continental slope offshore Nice (France),

International audienceTime-series bathymetric data acquired from 1967 to 2011 are used to evaluate the morphological evolution of the continental shelf and upper continental slope off the city of Nice (SE France, Ligurian Sea). Mapping in water depths of 0–300 m was undertaken to identify the changing morphology of landslide scars and their erosive chutes. Quantitative Digital Terrain Model (DTM) comparisons reveal areas of erosion and deposition over intervals of 5–8 years. Sediment remobilization events on the upper slope (above depths of 200 m) are frequent and significant; landslide scars with volumes > 25,000 m3 can occur with frequencies of 200 m). Periods of quiescence (1980–1990 and 2006–2011) are seen to alternate with periods when rapid retrogressive failure increase sediment volumes eroded from the upper slope-shelf transition by an order of magnitude (1999–2006). Temporal variations in landslide activity were correlated to several potential triggering factors that individually would not induce failures, including earthquake activity, rapid deposition of fine-grained sediments on a steep slope, and rainfall leading to fresh groundwater circulation below the shelf. This 4D bathymetric study suggests that over the last 50 years the most important factor triggering landslides offshore Nice is overpressure due to freshwater outflows

La méthode de diagnostic partagé : comprendre et analyser un territoire avec les représentations spatiales schématiques pour produire le « Dire de l’État »

4 page de la mallette pédagogique d’analyse territoriale, DREAL Poitou-Charente

La méthode de diagnostic partagé : comprendre et analyser un territoire avec les représentations spatiales schématiques pour produire le « Dire de l’État »

4 page de la mallette pédagogique d’analyse territoriale, DREAL Poitou-Charente