Axonal extension from dorsal root ganglia on fibrillar and highly aligned poly(lactic acid)-polypyrrole substrates obtained by two different techniques: Electrospun nanofibres and extruded microfibres

[EN] The biological behaviour of Schwann cells (SCs) and dorsal root ganglia (DRG) on fibrillar, highly aligned and electroconductive substrates obtained by two different techniques is studied. Mats formed by nanometer-sized fibres of poly(lactic acid) (PLA) are obtained by the electrospinning technique, while bundles formed by micrometer-sized extruded PLA fibres are obtained by grouping microfibres together. Both types of substrates are coated with the electrically conductive polymer polypyrrole (PPy) and their morphological, physical and electrical characterization is carried out. SCs on micrometer-sized substrates show a higher motility and cell-cell interaction, while a higher cell-material interaction with a lower cell motility is observed for nanometer-sized substrates. This higher motility and cell-cell interaction of SCs on the micrometer-sized substrates entails a higher axonal growth from DRG, since the migration of SCs from the DRG body is accelerated and, therefore, the SCs tapestry needed for the axonal growth is formed earlier on the substrate. A higher length and area of the axons is observed for these micrometer-sized substrates, as well as a higher level of axonal sprouting when compared with the nanometer-sized ones. These substrates offer the possibility of being electrically stimulated in different tissue engineering applications of the nervous system.The authors acknowledge financing from the Spanish Government's State Research Agency (AEI) through projects DPI2015-72863-EXP and RTI2018-095872-B-C22/ERDF. FGR acknowledges scholarship FPU16/01833 of the Spanish Ministry of Universities. We thank the Electron Microscopy Service at the UPV, where the FESEM images were obtainedGisbert-Roca, F.; Más Estellés, J.; Monleón Pradas, M.; Martínez-Ramos, C. (2020). Axonal extension from dorsal root ganglia on fibrillar and highly aligned poly(lactic acid)-polypyrrole substrates obtained by two different techniques: Electrospun nanofibres and extruded microfibres. International Journal of Biological Macromolecules. 163:1959-1969. https://doi.org/10.1016/j.ijbiomac.2020.09.181S19591969163Houschyar, K. S., Momeni, A., Pyles, M. N., Cha, J. Y., Maan, Z. N., Duscher, D., … Schoonhoven, J. van. (2016). The Role of Current Techniques and Concepts in Peripheral Nerve Repair. Plastic Surgery International, 2016, 1-8. doi:10.1155/2016/4175293Daly, W., Yao, L., Zeugolis, D., Windebank, A., & Pandit, A. (2011). A biomaterials approach to peripheral nerve regeneration: bridging the peripheral nerve gap and enhancing functional recovery. Journal of The Royal Society Interface, 9(67), 202-221. doi:10.1098/rsif.2011.0438De Ruiter, G. C. W., Malessy, M. J. A., Yaszemski, M. J., Windebank, A. J., & Spinner, R. J. (2009). Designing ideal conduits for peripheral nerve repair. Neurosurgical Focus, 26(2), E5. doi:10.3171/foc.2009.26.2.e5Tang-Schomer, M. D. (2018). 3D axon growth by exogenous electrical stimulus and soluble factors. Brain Research, 1678, 288-296. doi:10.1016/j.brainres.2017.10.032Sarker, M. D., Naghieh, S., McInnes, A. D., Schreyer, D. J., & Chen, X. (2018). Regeneration of peripheral nerves by nerve guidance conduits: Influence of design, biopolymers, cells, growth factors, and physical stimuli. Progress in Neurobiology, 171, 125-150. doi:10.1016/j.pneurobio.2018.07.002Kim, I. A., Park, S. A., Kim, Y. J., Kim, S.-H., Shin, H. J., Lee, Y. J., … Shin, J.-W. (2006). Effects of mechanical stimuli and microfiber-based substrate on neurite outgrowth and guidance. Journal of Bioscience and Bioengineering, 101(2), 120-126. doi:10.1263/jbb.101.120English, A. W., Schwartz, G., Meador, W., Sabatier, M. J., & Mulligan, A. (2007). Electrical stimulation promotes peripheral axon regeneration by enhanced neuronal neurotrophin signaling. Developmental Neurobiology, 67(2), 158-172. doi:10.1002/dneu.20339Schmidt, C. E., Shastri, V. R., Vacanti, J. P., & Langer, R. (1997). Stimulation of neurite outgrowth using an electrically conducting polymer. Proceedings of the National Academy of Sciences, 94(17), 8948-8953. doi:10.1073/pnas.94.17.8948Amani, H., Arzaghi, H., Bayandori, M., Dezfuli, A. S., Pazoki‐Toroudi, H., Shafiee, A., & Moradi, L. (2019). Controlling Cell Behavior through the Design of Biomaterial Surfaces: A Focus on Surface Modification Techniques. Advanced Materials Interfaces, 6(13), 1900572. doi:10.1002/admi.201900572Zhu, W., Masood, F., O’Brien, J., & Zhang, L. G. (2015). Highly aligned nanocomposite scaffolds by electrospinning and electrospraying for neural tissue regeneration. Nanomedicine: Nanotechnology, Biology and Medicine, 11(3), 693-704. doi:10.1016/j.nano.2014.12.001Lee, Y.-S., Collins, G., & Livingston Arinzeh, T. (2011). Neurite extension of primary neurons on electrospun piezoelectric scaffolds. Acta Biomaterialia, 7(11), 3877-3886. doi:10.1016/j.actbio.2011.07.013Lee, J. Y., Bashur, C. A., Goldstein, A. S., & Schmidt, C. E. (2009). Polypyrrole-coated electrospun PLGA nanofibers for neural tissue applications. Biomaterials, 30(26), 4325-4335. doi:10.1016/j.biomaterials.2009.04.042Zou, Y., Qin, J., Huang, Z., Yin, G., Pu, X., & He, D. (2016). Fabrication of Aligned Conducting PPy-PLLA Fiber Films and Their Electrically Controlled Guidance and Orientation for Neurites. ACS Applied Materials & Interfaces, 8(20), 12576-12582. doi:10.1021/acsami.6b00957Xu, Y., Huang, Z., Pu, X., Yin, G., & Zhang, J. (2019). Fabrication of Chitosan/Polypyrrole‐coated poly(L‐lactic acid)/Polycaprolactone aligned fibre films for enhancement of neural cell compatibility and neurite growth. Cell Proliferation, 52(3), e12588. doi:10.1111/cpr.12588Wang, H. B., Mullins, M. E., Cregg, J. M., McCarthy, C. W., & Gilbert, R. J. (2010). Varying the diameter of aligned electrospun fibers alters neurite outgrowth and Schwann cell migration. Acta Biomaterialia, 6(8), 2970-2978. doi:10.1016/j.actbio.2010.02.020Christopherson, G. T., Song, H., & Mao, H.-Q. (2009). The influence of fiber diameter of electrospun substrates on neural stem cell differentiation and proliferation. Biomaterials, 30(4), 556-564. doi:10.1016/j.biomaterials.2008.10.004Gnavi, S., Fornasari, B. E., Tonda-Turo, C., Ciardelli, G., Zanetti, M., Geuna, S., & Perroteau, I. (2015). The influence of electrospun fibre size on Schwann cell behaviour and axonal outgrowth. Materials Science and Engineering: C, 48, 620-631. doi:10.1016/j.msec.2014.12.055Bhardwaj, N., & Kundu, S. C. (2010). Electrospinning: A fascinating fiber fabrication technique. Biotechnology Advances, 28(3), 325-347. doi:10.1016/j.biotechadv.2010.01.004Agarwal, S., Wendorff, J. H., & Greiner, A. (2008). Use of electrospinning technique for biomedical applications. Polymer, 49(26), 5603-5621. doi:10.1016/j.polymer.2008.09.014Markus, A., Patel, T. D., & Snider, W. D. (2002). Neurotrophic factors and axonal growth. Current Opinion in Neurobiology, 12(5), 523-531. doi:10.1016/s0959-4388(02)00372-0Lu, P., & Tuszynski, M. H. (2008). Growth factors and combinatorial therapies for CNS regeneration. Experimental Neurology, 209(2), 313-320. doi:10.1016/j.expneurol.2007.08.004Lykissas, M., Batistatou, A., Charalabopoulos, K., & Beris, A. (2007). The Role of Neurotrophins in Axonal Growth, Guidance, and Regeneration. Current Neurovascular Research, 4(2), 143-151. doi:10.2174/156720207780637216Bregman, B. S., McAtee, M., Dai, H. N., & Kuhn, P. L. (1997). Neurotrophic Factors Increase Axonal Growth after Spinal Cord Injury and Transplantation in the Adult Rat. Experimental Neurology, 148(2), 475-494. doi:10.1006/exnr.1997.6705Freeman, M. R. (2006). Sculpting the nervous system: glial control of neuronal development. Current Opinion in Neurobiology, 16(1), 119-125. doi:10.1016/j.conb.2005.12.004Pompili, E., Ciraci, V., Leone, S., De Franchis, V., Familiari, P., Matassa, R., … Fabrizi, C. (2020). Thrombin regulates the ability of Schwann cells to support neuritogenesis and to maintain the integrity of the nodes of Ranvier. European Journal of Histochemistry, 64(2). doi:10.4081/ejh.2020.3109El Seblani, N., Welleford, A. S., Quintero, J. E., van Horne, C. G., & Gerhardt, G. A. (2020). Invited review: Utilizing peripheral nerve regenerative elements to repair damage in the CNS. Journal of Neuroscience Methods, 335, 108623. doi:10.1016/j.jneumeth.2020.108623Jessen, K. R., & Arthur-Farraj, P. (2019). Repair Schwann cell update: Adaptive reprogramming, EMT, and stemness in regenerating nerves. Glia, 67(3), 421-437. doi:10.1002/glia.23532Jessen, K. R., Mirsky, R., & Lloyd, A. C. (2015). Schwann Cells: Development and Role in Nerve Repair. Cold Spring Harbor Perspectives in Biology, 7(7), a020487. doi:10.1101/cshperspect.a020487Gomez-Sanchez, J. A., Pilch, K. S., van der Lans, M., Fazal, S. V., Benito, C., Wagstaff, L. J., … Jessen, K. R. (2017). After Nerve Injury, Lineage Tracing Shows That Myelin and Remak Schwann Cells Elongate Extensively and Branch to Form Repair Schwann Cells, Which Shorten Radically on Remyelination. The Journal of Neuroscience, 37(37), 9086-9099. doi:10.1523/jneurosci.1453-17.2017Wang, L.-X., Li, X.-G., & Yang, Y.-L. (2001). Preparation, properties and applications of polypyrroles. Reactive and Functional Polymers, 47(2), 125-139. doi:10.1016/s1381-5148(00)00079-1Le, T.-H., Kim, Y., & Yoon, H. (2017). Electrical and Electrochemical Properties of Conducting Polymers. Polymers, 9(12), 150. doi:10.3390/polym9040150Mattioli-Belmonte, M., Gabbanelli, F., Marcaccio, M., Giantomassi, F., Tarsi, R., Natali, D., … Biagini, G. (2005). Bio-characterisation of tosylate-doped polypyrrole films for biomedical applications. Materials Science and Engineering: C, 25(1), 43-49. doi:10.1016/j.msec.2004.04.002Sabouraud, G., Sadki, S., & Brodie, N. (2000). The mechanisms of pyrrole electropolymerization. Chemical Society Reviews, 29(5), 283-293. doi:10.1039/a807124aLi, C., Bai, H., & Shi, G. (2009). Conducting polymer nanomaterials: electrosynthesis and applications. Chemical Society Reviews, 38(8), 2397. doi:10.1039/b816681cAznar-Cervantes, S., Roca, M. I., Martinez, J. G., Meseguer-Olmo, L., Cenis, J. L., Moraleda, J. M., & Otero, T. F. (2012). Fabrication of conductive electrospun silk fibroin scaffolds by coating with polypyrrole for biomedical applications. Bioelectrochemistry, 85, 36-43. doi:10.1016/j.bioelechem.2011.11.008Sun, X., Peng, J., Zhou, J., Wang, Y., Cheng, L., & Wu, Z. (2016). Preparation of polypyrrole-embedded electrospun poly(lactic acid) nanofibrous scaffolds for nerve tissue engineering. Neural Regeneration Research, 11(10), 1644. doi:10.4103/1673-5374.193245George, P. M., Lyckman, A. W., LaVan, D. A., Hegde, A., Leung, Y., Avasare, R., … Sur, M. (2005). Fabrication and biocompatibility of polypyrrole implants suitable for neural prosthetics. Biomaterials, 26(17), 3511-3519. doi:10.1016/j.biomaterials.2004.09.037Lunt, J. (1998). Large-scale production, properties and commercial applications of polylactic acid polymers. Polymer Degradation and Stability, 59(1-3), 145-152. doi:10.1016/s0141-3910(97)00148-1Ramot, Y., Haim-Zada, M., Domb, A. J., & Nyska, A. (2016). Biocompatibility and safety of PLA and its copolymers. Advanced Drug Delivery Reviews, 107, 153-162. doi:10.1016/j.addr.2016.03.012Da Silva, D., Kaduri, M., Poley, M., Adir, O., Krinsky, N., Shainsky-Roitman, J., & Schroeder, A. (2018). Biocompatibility, biodegradation and excretion of polylactic acid (PLA) in medical implants and theranostic systems. Chemical Engineering Journal, 340, 9-14. doi:10.1016/j.cej.2018.01.010Wan, Y., & Wen, D. (2005). Preparation and characterization of porous conducting poly(dl-lactide) composite membranes. Journal of Membrane Science, 246(2), 193-201. doi:10.1016/j.memsci.2004.07.032Shi, G., Rouabhia, M., Wang, Z., Dao, L. H., & Zhang, Z. (2004). A novel electrically conductive and biodegradable composite made of polypyrrole nanoparticles and polylactide. Biomaterials, 25(13), 2477-2488. doi:10.1016/j.biomaterials.2003.09.032Wang, Z., Roberge, C., Dao, L. H., Wan, Y., Shi, G., Rouabhia, M., … Zhang, Z. (2004). In vivo evaluation of a novel electrically conductive polypyrrole/poly(D,L-lactide) composite and polypyrrole-coated poly(D,L-lactide-co-glycolide) membranes. Journal of Biomedical Materials Research, 70A(1), 28-38. doi:10.1002/jbm.a.30047Woodruff, M. A., & Hutmacher, D. W. (2010). The return of a forgotten polymer—Polycaprolactone in the 21st century. Progress in Polymer Science, 35(10), 1217-1256. doi:10.1016/j.progpolymsci.2010.04.002Lam, C. X. F., Hutmacher, D. W., Schantz, J.-T., Woodruff, M. A., & Teoh, S. H. (2009). Evaluation of polycaprolactone scaffold degradation for 6 monthsin vitroandin vivo. Journal of Biomedical Materials Research Part A, 90A(3), 906-919. doi:10.1002/jbm.a.32052Schindelin, J., Arganda-Carreras, I., Frise, E., Kaynig, V., Longair, M., Pietzsch, T., … Cardona, A. (2012). Fiji: an open-source platform for biological-image analysis. Nature Methods, 9(7), 676-682. doi:10.1038/nmeth.2019Callens, S. J. P., Uyttendaele, R. J. C., Fratila-Apachitei, L. E., & Zadpoor, A. A. (2020). Substrate curvature as a cue to guide spatiotemporal cell and tissue organization. Biomaterials, 232, 119739. doi:10.1016/j.biomaterials.2019.119739Rolli, C. G., Nakayama, H., Yamaguchi, K., Spatz, J. P., Kemkemer, R., & Nakanishi, J. (2012). Switchable adhesive substrates: Revealing geometry dependence in collective cell behavior. Biomaterials, 33(8), 2409-2418. doi:10.1016/j.biomaterials.2011.12.012Doxzen, K., Vedula, S. R. K., Leong, M. C., Hirata, H., Gov, N. S., Kabla, A. J., … Lim, C. T. (2013). Guidance of collective cell migration by substrate geometry. Integrative Biology, 5(8), 1026. doi:10.1039/c3ib40054aKim, Y., Haftel, V. K., Kumar, S., & Bellamkonda, R. V. (2008). The role of aligned polymer fiber-based constructs in the bridging of long peripheral nerve gaps. Biomaterials, 29(21), 3117-3127. doi:10.1016/j.biomaterials.2008.03.042Schnell, E., Klinkhammer, K., Balzer, S., Brook, G., Klee, D., Dalton, P., & Mey, J. (2007). Guidance of glial cell migration and axonal growth on electrospun nanofibers of poly-ε-caprolactone and a collagen/poly-ε-caprolactone blend. Biomaterials, 28(19), 3012-3025. doi:10.1016/j.biomaterials.2007.03.00

Electrical Stimulation Increases Axonal Growth from Dorsal Root Ganglia Co-Cultured with Schwann Cells in Highly Aligned PLA-PPy-Au Microfiber Substrates

[EN] Nerve regeneration is a slow process that needs to be guided for distances greater than 5 mm. For this reason, different strategies are being studied to guide axonal growth and accelerate the axonal growth rate. In this study, we employ an electroconductive fibrillar substrate that is able to topographically guide axonal growth while accelerating the axonal growth rate when subjected to an exogenous electric field. Dorsal root ganglia were seeded in co-culture with Schwann cells on a substrate of polylactic acid microfibers coated with the electroconductive polymer polypyrrole, adding gold microfibers to increase its electrical conductivity. The substrate is capable of guiding axonal growth in a highly aligned manner and, when subjected to an electrical stimulation, an improvement in axonal growth is observed. As a result, an increase in the maximum length of the axons of 19.2% and an increase in the area occupied by the axons of 40% were obtained. In addition, an upregulation of the genes related to axon guidance, axogenesis, Schwann cells, proliferation and neurotrophins was observed for the electrically stimulated group. Therefore, our device is a good candidate for nerve regeneration therapies.This research was funded by the Spanish Government's State Research Agency (AEI) through project RTI2018-095872-B-C22/ERDF and by RISEUP project FetOpen in H2020 Program: RISEUP 964562 H2020 FetOpen program.Gisbert Roca, F.; Serrano Requena, S.; Monleón Pradas, M.; Martínez-Ramos, C. (2022). Electrical Stimulation Increases Axonal Growth from Dorsal Root Ganglia Co-Cultured with Schwann Cells in Highly Aligned PLA-PPy-Au Microfiber Substrates. International Journal of Molecular Sciences. 23:1-22. https://doi.org/10.3390/ijms231263621222

Activation of the acute inflammatory phase response in idiopathic nephrotic syndrome: association with clinicopathological phenotypes and with response to corticosteroids

Glomeruloesclerosis; Inflamación; Síndrome nefróticoGlomerulosclerosis; Inflammation; Nephrotic syndromeGlomeruloesclerosi; Inflamació; Síndrome nefròticaBackground Data on the activation of the acute inflammatory response and its clinicopathological associations in idiopathic nephrotic syndrome (INS) are scarce and discordant. Objective To analyse the associations between the activation of the inflammatory response, the clinicopathological characteristics of disease and the response to treatment with steroids in patients with INS. Methods A total of 101 patients with INS due to minimal change disease (MCD; n = 44), focal segmental glomerulosclerosis (FSGS; n = 33) and membranous nephropathy (MN; n = 24) and 50 healthy controls were included. At diagnosis, we measured the levels of haemopexin (Hx), haptoglobin (Hgl), interleukin-6 (IL-6), soluble urokinase-type plasminogen activator receptor (suPAR), tumour necrosis factor-α (TNF-α), soluble IL-1 receptor, interferon-γ and C-reactive protein. We analysed their clinicopathological associations. In MCD and FSGS patients, we determined the association between the levels of these variables and steroid resistance. Results The levels of Hx, Hgl, TNF-α, suPAR and IL-6 were higher in patients with INS than in healthy controls, and were not associated with proteinuria, estimated glomerular filtration rate or serum albumin. In MCD and FSGS patients, Hx, Hgl, IL-6 and TNF-α levels were similar and significantly higher than in MN patients. In patients with MCD and FSGS, multivariate analyses identified FSGS and the levels of Hx, Hgl or IL-6 as independent predictors of steroid resistance. Conclusions The activation of the inflammatory response in patients with INS is heterogeneous and more prevalent in MCD or FSGS patients than in those with MN. In MCD and FSGS, elevated levels of Hx, Hgl or IL-6 are independently associated with steroid resistance

Solid Polymer Electrolytes Based on Polylactic Acid Nanofiber Mats Coated with Polypyrrole

This is the peer reviewed version of the following article: Gisbert, F., García-Bernabé, A., Compañ, V., Martínez-Ramos, C., Monleón, M., Solid Polymer Electrolytes Based on Polylactic Acid Nanofiber Mats Coated with Polypyrrole. Macromol. Mater. Eng. 2021, 306, 2000584, which has been published in final form at https://doi.org/10.1002/mame.202000584. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The production of electroconductive nanofiber membranes made from polylactic acid (PLA) coated with polypyrrole (PPy) is investigated, performing a scanning of different reaction parameters and studying their physicochemical and dielectric properties. Depending on PPy content, a transition between conduction mechanisms is observed, with a temperature-dependent relaxation process for samples without PPy, a temperature-independent conduction process for samples with high contents of PPy and a combination of both processes for samples with low contents of PPy. A homogeneous and continuous coating is achieved from 23 wt% PPy, observing a percolation effect around 27 wt% PPy. Higher wt% PPy allow to obtain higher conductivities, but PPy aggregates appear from 34% wt% PPy. The high conductivity values obtained for electrospun membranes both through-plane and in-plane (above 0.05 and 0.20 S cm¿1, respectively, at room temperature) for the highest wt% of PPy, their porous structure with high specific surface area and their thermal stability below 140 °C make them candidates for many potential applications as solid polymer electrolytes in, for example, batteries, supercapacitors, sensors, photosensors, or polymer electrolyte membrane fuel cells (PEMFCs). In addition, the biocompatibility of PLA-PPy membranes expand their potential applications also in the field of tissue engineering and implantable devices.The authors acknowledge financing from the Spanish Government's State Research Agency (AEI) through projects DPI2015-72863-EXP and RTI2018-095872-B-C22/ERDF. FGR acknowledges the scholarship FPU16/01833 of the Spanish Ministry of Universities. The authors thank the Electron Microscopy Service at the UPV, where the FESEM images were obtained.Gisbert-Roca, F.; Garcia-Bernabe, A.; Compañ Moreno, V.; Martínez-Ramos, C.; Monleón Pradas, M. (2021). Solid Polymer Electrolytes Based on Polylactic Acid Nanofiber Mats Coated with Polypyrrole. Macromolecular Materials and Engineering. 306(2):1-14. https://doi.org/10.1002/mame.202000584S1143062McNeill, R., Siudak, R., Wardlaw, J., & Weiss, D. (1963). Electronic Conduction in Polymers. I. The Chemical Structure of Polypyrrole. Australian Journal of Chemistry, 16(6), 1056. doi:10.1071/ch9631056Bolto, B., & Weiss, D. (1963). Electronic Conduction in Polymers. II. The Electrochemical Reduction of Polypyrrole at Controlled Potential. Australian Journal of Chemistry, 16(6), 1076. doi:10.1071/ch9631076Bolto, B., McNeill, R., & Weiss, D. (1963). Electronic Conduction in Polymers. III. Electronic Properties of Polypyrrole. Australian Journal of Chemistry, 16(6), 1090. doi:10.1071/ch9631090McNeill, R., Weiss, D., & Willis, D. (1965). Electronic conduction in polymers. IV. Polymers from imidazole and pyridine. Australian Journal of Chemistry, 18(4), 477. doi:10.1071/ch9650477Bolto, B., Weiss, D., & Willis, D. (1965). Electronic conduction in polymers. V. Aromatic semiconducting polymers. Australian Journal of Chemistry, 18(4), 487. doi:10.1071/ch9650487Shirakawa, H., Louis, E. J., MacDiarmid, A. G., Chiang, C. K., & Heeger, A. J. (1977). Synthesis of electrically conducting organic polymers: halogen derivatives of polyacetylene, (CH) x. Journal of the Chemical Society, Chemical Communications, (16), 578. doi:10.1039/c39770000578Hammache, H., Makhloufi, L., & Saidani, B. (2003). Corrosion protection of iron by polypyrrole modified by copper using the cementation process. Corrosion Science, 45(9), 2031-2042. doi:10.1016/s0010-938x(03)00043-xMattioli-Belmonte, M., Gabbanelli, F., Marcaccio, M., Giantomassi, F., Tarsi, R., Natali, D., … Biagini, G. (2005). Bio-characterisation of tosylate-doped polypyrrole films for biomedical applications. Materials Science and Engineering: C, 25(1), 43-49. doi:10.1016/j.msec.2004.04.002CAREEM, M. (2004). Dependence of force produced by polypyrrole-based artificial muscles on ionic species involved. Solid State Ionics, 175(1-4), 725-728. doi:10.1016/j.ssi.2004.01.080Ge, D., Tian, X., Qi, R., Huang, S., Mu, J., Hong, S., … Shi, W. (2009). A polypyrrole-based microchip for controlled drug release. Electrochimica Acta, 55(1), 271-275. doi:10.1016/j.electacta.2009.08.049Sharma, R. K., Rastogi, A. C., & Desu, S. B. (2008). Pulse polymerized polypyrrole electrodes for high energy density electrochemical supercapacitor. Electrochemistry Communications, 10(2), 268-272. doi:10.1016/j.elecom.2007.12.004Rubio Retama, J., López Cabarcos, E., Mecerreyes, D., & López-Ruiz, B. (2004). Design of an amperometric biosensor using polypyrrole-microgel composites containing glucose oxidase. Biosensors and Bioelectronics, 20(6), 1111-1117. doi:10.1016/j.bios.2004.05.018Wang, L.-X., Li, X.-G., & Yang, Y.-L. (2001). Preparation, properties and applications of polypyrroles. Reactive and Functional Polymers, 47(2), 125-139. doi:10.1016/s1381-5148(00)00079-1Sabouraud, G., Sadki, S., & Brodie, N. (2000). The mechanisms of pyrrole electropolymerization. Chemical Society Reviews, 29(5), 283-293. doi:10.1039/a807124aLi, C., Bai, H., & Shi, G. (2009). Conducting polymer nanomaterials: electrosynthesis and applications. Chemical Society Reviews, 38(8), 2397. doi:10.1039/b816681cBrahim, S. I., Maharajh, D., Narinesingh, D., & Guiseppi-Elie, A. (2002). DESIGN AND CHARACTERIZATION OF A GALACTOSE BIOSENSOR USING A NOVEL POLYPYRROLE-HYDROGEL COMPOSITE MEMBRANE. Analytical Letters, 35(5), 797-812. doi:10.1081/al-120004070Jun, H.-K., Hoh, Y.-S., Lee, B.-S., Lee, S.-T., Lim, J.-O., Lee, D.-D., & Huh, J.-S. (2003). Electrical properties of polypyrrole gas sensors fabricated under various pretreatment conditions. Sensors and Actuators B: Chemical, 96(3), 576-581. doi:10.1016/j.snb.2003.06.002Kisiel, A., Mazur, M., Kuśnieruk, S., Kijewska, K., Krysiński, P., & Michalska, A. (2010). Polypyrrole microcapsules as a transducer for ion-selective electrodes. Electrochemistry Communications, 12(11), 1568-1571. doi:10.1016/j.elecom.2010.08.035Yamamoto, H., Fukuda, M., Isa, I., & Yoshino, K. (1993). Tantalum electrolytic capacitor employing polypyrrole as solid electrolyte. Electronics and Communications in Japan (Part II: Electronics), 76(6), 88-98. doi:10.1002/ecjb.4420760610Yamamoto, H., Oshima, M., Fukuda, M., Isa, I., & Yoshino, K. (1996). Characteristics of aluminium solid electrolytic capacitors using a conducting polymer. Journal of Power Sources, 60(2), 173-177. doi:10.1016/s0378-7753(96)80007-3Sultana, I., Rahman, M. M., Wang, J., Wang, C., Wallace, G. G., & Liu, H.-K. (2012). All-polymer battery system based on polypyrrole (PPy)/para (toluene sulfonic acid) (pTS) and polypyrrole (PPy)/indigo carmine (IC) free standing films. Electrochimica Acta, 83, 209-215. doi:10.1016/j.electacta.2012.08.043Xia, J., Chen, L., & Yanagida, S. (2011). Application of polypyrrole as a counter electrode for a dye-sensitized solar cell. Journal of Materials Chemistry, 21(12), 4644. doi:10.1039/c0jm04116eAlmuntaser, F. M. A., Majumder, S., Baviskar, P. K., Sali, J. V., & Sankapal, B. R. (2017). Synthesis and characterization of polypyrrole and its application for solar cell. Applied Physics A, 123(8). doi:10.1007/s00339-017-1131-yHao, D., Xu, B., & Cai, Z. (2018). Polypyrrole coated knitted fabric for robust wearable sensor and heater. Journal of Materials Science: Materials in Electronics, 29(11), 9218-9226. doi:10.1007/s10854-018-8950-2Lima, R. M. A. P., Alcaraz-Espinoza, J. J., da Silva, F. A. G., & de Oliveira, H. P. (2018). Multifunctional Wearable Electronic Textiles Using Cotton Fibers with Polypyrrole and Carbon Nanotubes. ACS Applied Materials & Interfaces, 10(16), 13783-13795. doi:10.1021/acsami.8b04695Lee, C. Y., Lee, D. E., Jeong, C. K., Hong, Y. K., Shim, J. H., Joo, J., … Yang, H. G. (2002). Electromagnetic interference shielding by using conductive polypyrrole and metal compound coated on fabrics. Polymers for Advanced Technologies, 13(8), 577-583. doi:10.1002/pat.227Håkansson, E., Amiet, A., Nahavandi, S., & Kaynak, A. (2007). Electromagnetic interference shielding and radiation absorption in thin polypyrrole films. European Polymer Journal, 43(1), 205-213. doi:10.1016/j.eurpolymj.2006.10.001Zhao, H., Li, L., Yang, J., & Zhang, Y. (2008). Nanostructured polypyrrole/carbon composite as Pt catalyst support for fuel cell applications. Journal of Power Sources, 184(2), 375-380. doi:10.1016/j.jpowsour.2008.03.024Huang, S.-Y., Ganesan, P., & Popov, B. N. (2009). Development of conducting polypyrrole as corrosion-resistant catalyst support for polymer electrolyte membrane fuel cell (PEMFC) application. Applied Catalysis B: Environmental, 93(1-2), 75-81. doi:10.1016/j.apcatb.2009.09.014Park, H., Kim, Y., Choi, Y. S., Hong, W. H., & Jung, D. (2008). Surface chemistry and physical properties of Nafion/polypyrrole/Pt composite membrane prepared by chemical in situ polymerization for DMFC. Journal of Power Sources, 178(2), 610-619. doi:10.1016/j.jpowsour.2007.08.050Feng, C., Ma, L., Li, F., Mai, H., Lang, X., & Fan, S. (2010). A polypyrrole/anthraquinone-2,6-disulphonic disodium salt (PPy/AQDS)-modified anode to improve performance of microbial fuel cells. Biosensors and Bioelectronics, 25(6), 1516-1520. doi:10.1016/j.bios.2009.10.009Lee, J. Y., Bashur, C. A., Goldstein, A. S., & Schmidt, C. E. (2009). Polypyrrole-coated electrospun PLGA nanofibers for neural tissue applications. Biomaterials, 30(26), 4325-4335. doi:10.1016/j.biomaterials.2009.04.042Zhou, H., Liu, Z., Liu, X., & Chen, Q. (2016). Umbilical cord-derived mesenchymal stem cell transplantation combined with hyperbaric oxygen treatment for repair of traumatic brain injury. Neural Regeneration Research, 11(1), 107. doi:10.4103/1673-5374.175054Aznar-Cervantes, S., Roca, M. I., Martinez, J. G., Meseguer-Olmo, L., Cenis, J. L., Moraleda, J. M., & Otero, T. F. (2012). Fabrication of conductive electrospun silk fibroin scaffolds by coating with polypyrrole for biomedical applications. Bioelectrochemistry, 85, 36-43. doi:10.1016/j.bioelechem.2011.11.008George, P. M., Lyckman, A. W., LaVan, D. A., Hegde, A., Leung, Y., Avasare, R., … Sur, M. (2005). Fabrication and biocompatibility of polypyrrole implants suitable for neural prosthetics. Biomaterials, 26(17), 3511-3519. doi:10.1016/j.biomaterials.2004.09.037Uyar, T., Toppare, L., & Hacaloglu, J. (2001). PYROLYSIS OF BF4- DOPED POLYPYRROLE BY DIRECT INSERTION PROBE PYROLYSIS MASS SPECTROMETRY. Journal of Macromolecular Science, Part A, 38(11), 1141-1150. doi:10.1081/ma-100107134Zinger, B., Shaier, P., & Zemel, A. (1991). Flexible polypyrrole/ClO4 films formed in aqueous solutions. Synthetic Metals, 40(3), 283-297. doi:10.1016/0379-6779(91)92070-xPeres, R. C. D., Juliano, V. F., De Paoli, M.-A., Panero, S., & Scrosati, B. (1993). Electrochromic properties of dodecyclbenzenesulfonate doped poly(pyrrole). Electrochimica Acta, 38(7), 869-876. doi:10.1016/0013-4686(93)87003-vDe Paoli, M.-A., Peres, R. C. D., Panero, S., & Scrosati, B. (1992). Properties of electrochemically synthesized polymer electrodes—X. Study of polypyrrole/dodecylbenzene sulfonate. Electrochimica Acta, 37(7), 1173-1182. doi:10.1016/0013-4686(92)85053-nLim, H. K., Lee, S. O., Song, K. J., Kim, S. G., & Kim, K. H. (2005). Synthesis and properties of soluble polypyrrole doped with dodecylbenzenesulfonate and combined with polymeric additive poly(ethylene glycol). Journal of Applied Polymer Science, 97(3), 1170-1175. doi:10.1002/app.21824Carragher, U., & Breslin, C. B. (2018). Polypyrrole doped with dodecylbenzene sulfonate as a protective coating for copper. Electrochimica Acta, 291, 362-372. doi:10.1016/j.electacta.2018.08.155Arribas, C., & Rueda, D. (1996). Preparation of conductive polypyrrole-polystyrene sulfonate by chemical polymerization. Synthetic Metals, 79(1), 23-26. doi:10.1016/0379-6779(96)80125-1Wu, T.-M., Chang, H.-L., & Lin, Y.-W. (2009). Synthesis and characterization of conductive polypyrrole with improved conductivity and processability. Polymer International, 58(9), 1065-1070. doi:10.1002/pi.2634Jin, C., Yang, F., & Yang, W. (2006). Electropolymerization and ion exchange properties of a polypyrrole film doped bypara-toluene sulfonate. Journal of Applied Polymer Science, 101(4), 2518-2522. doi:10.1002/app.23775Kaynak, A. (2009). Decay of electrical conductivity in p-toluene sulfonate doped polypyrrole films. Fibers and Polymers, 10(5), 590-593. doi:10.1007/s12221-010-0590-ySamuelson, L. A., & Druy, M. A. (1986). Kinetics of the degradation of electrical conductivity in polypyrrole. Macromolecules, 19(3), 824-828. doi:10.1021/ma00157a057Hou, H., Yu, C., Liu, X., Yao, Y., Liao, Q., Dai, Z., & Li, D. (2018). Waste-loofah-derived carbon micro/nanoparticles for lithium ion battery anode. Surface Innovations, 6(3), 159-166. doi:10.1680/jsuin.17.00068Sultana, I., Rahman, M. M., Li, S., Wang, J., Wang, C., Wallace, G. G., & Liu, H.-K. (2012). Electrodeposited polypyrrole (PPy)/para (toluene sulfonic acid) (pTS) free-standing film for lithium secondary battery application. Electrochimica Acta, 60, 201-205. doi:10.1016/j.electacta.2011.11.037Jérôme, C., Martinot, L., Strivay, D., Weber, G., & Jérôme, R. (2001). Controlled exchange of metallic cations by polypyrrole-based resins. Synthetic Metals, 118(1-3), 45-55. doi:10.1016/s0379-6779(00)00275-7Zhao, H., Price, W. E., Too, C. O., Wallace, G. G., & Zhou, D. (1996). Parameters influencing transport across conducting electroactive polymer membranes. Journal of Membrane Science, 119(2), 199-212. doi:10.1016/0376-7388(96)00130-5Ansari Khalkhali, R., Price, W. ., & Wallace, G. . (2003). Quartz crystal microbalance studies of the effect of solution temperature on the ion-exchange properties of polypyrrole conducting electroactive polymers. Reactive and Functional Polymers, 56(3), 141-146. doi:10.1016/s1381-5148(03)00055-5Pyo, M., Reynolds, J. R., Warren, L. F., & Marcy, H. O. (1994). Long-term redox switching stability of polypyrrole. Synthetic Metals, 68(1), 71-77. doi:10.1016/0379-6779(94)90149-xMurray, P., Spinks, G. M., Wallace, G. G., & Burford, R. P. (1997). In-situ mechanical properties of tosylate doped (pts) polypyrrole. Synthetic Metals, 84(1-3), 847-848. doi:10.1016/s0379-6779(96)04177-xChengyou, J., & Fenglin, Y. (2006). Ion transport and conformational relaxation of a polypyrrole film in aqueous solutions. Sensors and Actuators B: Chemical, 114(2), 737-739. doi:10.1016/j.snb.2005.06.026Li, S., Qiu, Y., & Guo, X. (2009). Influence of doping anions on the ion exchange behavior of polypyrrole. Journal of Applied Polymer Science, 114(4), 2307-2314. doi:10.1002/app.30721Raudsepp, T., Marandi, M., Tamm, T., Sammelselg, V., & Tamm, J. (2014). Influence of ion-exchange on the electrochemical properties of polypyrrole films. Electrochimica Acta, 122, 79-86. doi:10.1016/j.electacta.2013.08.083Syritski, V., Öpik, A., & Forsén, O. (2003). Ion transport investigations of polypyrroles doped with different anions by EQCM and CER techniques. Electrochimica Acta, 48(10), 1409-1417. doi:10.1016/s0013-4686(03)00018-5Fang, Y., Liu, J., Yu, D. J., Wicksted, J. P., Kalkan, K., Topal, C. O., … Li, J. (2010). Self-supported supercapacitor membranes: Polypyrrole-coated carbon nanotube networks enabled by pulsed electrodeposition. Journal of Power Sources, 195(2), 674-679. doi:10.1016/j.jpowsour.2009.07.033Qian, T., Yu, C., Zhou, X., Ma, P., Wu, S., Xu, L., & Shen, J. (2014). Ultrasensitive dopamine sensor based on novel molecularly imprinted polypyrrole coated carbon nanotubes. Biosensors and Bioelectronics, 58, 237-241. doi:10.1016/j.bios.2014.02.081Zhang, J., & Zhao, X. S. (2012). Conducting Polymers Directly Coated on Reduced Graphene Oxide Sheets as High-Performance Supercapacitor Electrodes. The Journal of Physical Chemistry C, 116(9), 5420-5426. doi:10.1021/jp211474eLi, W., Zhang, Q., Zheng, G., Seh, Z. W., Yao, H., & Cui, Y. (2013). Understanding the Role of Different Conductive Polymers in Improving the Nanostructured Sulfur Cathode Performance. Nano Letters, 13(11), 5534-5540. doi:10.1021/nl403130hZhu, C., Zhai, J., Wen, D., & Dong, S. (2012). Graphene oxide/polypyrrole nanocomposites: one-step electrochemical doping, coating and synergistic effect for energy storage. Journal of Materials Chemistry, 22(13), 6300. doi:10.1039/c2jm16699bDing, C., Qian, X., Yu, G., & An, X. (2010). Dopant effect and characterization of polypyrrole-cellulose composites prepared by in situ polymerization process. Cellulose, 17(6), 1067-1077. doi:10.1007/s10570-010-9442-6Yuan, L., Yao, B., Hu, B., Huo, K., Chen, W., & Zhou, J. (2013). Polypyrrole-coated paper for flexible solid-state energy storage. Energy & Environmental Science, 6(2), 470. doi:10.1039/c2ee23977aLu, Y., Tao, P., Zhang, N., & Nie, S. (2020). Preparation and thermal stability evaluation of cellulose nanofibrils from bagasse pulp with differing hemicelluloses contents. Carbohydrate Polymers, 245, 116463. doi:10.1016/j.carbpol.2020.116463Zhang, Y., Hao, N., Lin, X., & Nie, S. (2020). Emerging challenges in the thermal management of cellulose nanofibril-based supercapacitors, lithium-ion batteries and solar cells: A review. Carbohydrate Polymers, 234, 115888. doi:10.1016/j.carbpol.2020.115888Wang, Y., Sotzing, G. A., & Weiss, R. A. (2008). Preparation of Conductive Polypyrrole/Polyurethane Composite Foams by In situ Polymerization of Pyrrole. Chemistry of Materials, 20(7), 2574-2582. doi:10.1021/cm800005rLunt, J. (1998). Large-scale production, properties and commercial applications of polylactic acid polymers. Polymer Degradation and Stability, 59(1-3), 145-152. doi:10.1016/s0141-3910(97)00148-1Mróz, P., Białas, S., Mucha, M., & Kaczmarek, H. (2013). Thermogravimetric and DSC testing of poly(lactic acid) nanocomposites. Thermochimica Acta, 573, 186-192. doi:10.1016/j.tca.2013.09.012Araque-Monrós, M. C., Vidaurre, A., Gil-Santos, L., Gironés Bernabé, S., Monleón-Pradas, M., & Más-Estellés, J. (2013). Study of the degradation of a new PLA braided biomaterial in buffer phosphate saline, basic and acid media, intended for the regeneration of tendons and ligaments. Polymer Degradation and Stability, 98(9), 1563-1570. doi:10.1016/j.polymdegradstab.2013.06.031Ramot, Y., Haim-Zada, M., Domb, A. J., & Nyska, A. (2016). Biocompatibility and safety of PLA and its copolymers. Advanced Drug Delivery Reviews, 107, 153-162. doi:10.1016/j.addr.2016.03.012Da Silva, D., Kaduri, M., Poley, M., Adir, O., Krinsky, N., Shainsky-Roitman, J., & Schroeder, A. (2018). Biocompatibility, biodegradation and excretion of polylactic acid (PLA) in medical implants and theranostic systems. Chemical Engineering Journal, 340, 9-14. doi:10.1016/j.cej.2018.01.010Schindelin, J., Arganda-Carreras, I., Frise, E., Kaynig, V., Longair, M., Pietzsch, T., … Cardona, A. (2012). Fiji: an open-source platform for biological-image analysis. Nature Methods, 9(7), 676-682. doi:10.1038/nmeth.2019Garlotta, D. (2001). Journal of Polymers and the Environment, 9(2), 63-84. doi:10.1023/a:1020200822435Mofokeng, J. P., Luyt, A. S., Tábi, T., & Kovács, J. (2011). Comparison of injection moulded, natural fibre-reinforced composites with PP and PLA as matrices. Journal of Thermoplastic Composite Materials, 25(8), 927-948. doi:10.1177/0892705711423291Chieng, B., Ibrahim, N., Yunus, W., & Hussein, M. (2013). Poly(lactic acid)/Poly(ethylene glycol) Polymer Nanocomposites: Effects of Graphene Nanoplatelets. Polymers, 6(1), 93-104. doi:10.3390/polym6010093Chitte, H. K., Shinde, G. N., Bhat, N. V., & Walunj, V. E. (2011). Synthesis of Polypyrrole Using Ferric Chloride (FeCl<sub>3</sub>) as Oxidant Together with Some Dopants for Use in Gas Sensors. Journal of Sensor Technology, 01(02), 47-56. doi:10.4236/jst.2011.12007Uyar, T., Toppare, L., & Hacaloğlu, J. (2002). Characterization of electrochemically synthesized p-toluene sulfonic acid doped polypyrrole by direct insertion probe pyrolysis mass spectrometry. Journal of Analytical and Applied Pyrolysis, 64(1), 1-13. doi:10.1016/s0165-2370(01)00166-8Schütt, H. J., & Gerdes, E. (1992). Space-charge relaxation in ionicly conducting oxide glasses. I. Model and frequency response. Journal of Non-Crystalline Solids, 144, 1-13. doi:10.1016/s0022-3093(05)80377-1Schütt, H. J., & Gerdes, E. (1992). Space-charge relaxation in ionicly conducting glasses. II. Free carrier concentration and mobility. Journal of Non-Crystalline Solids, 144, 14-20. doi:10.1016/s0022-3093(05)80378-3Sørensen, T. S., Compañ, V., & Diaz-Calleja, R. (1996). Complex permittivity of a film of poly[4-(acryloxy)phenyl-(4-chlorophenyl)methanone] containing free ion impurities and the separation of the contributions from interfacial polarization, Maxwell–Wagner–Sillars effects and dielectric relaxations of the polymer chains. J. Chem. Soc., Faraday Trans., 92(11), 1947-1957. doi:10.1039/ft9969201947Serghei, A., Tress, M., Sangoro, J. R., & Kremer, F. (2009). Electrode polarization and charge transport at solid interfaces. Physical Review B, 80(18). doi:10.1103/physrevb.80.184301Fragiadakis, D., Dou, S., Colby, R. H., & Runt, J. (2009). Molecular mobility and Li+ conduction in polyester copolymer ionomers based on poly(ethylene oxide). The Journal of Chemical Physics, 130(6), 064907. doi:10.1063/1.3063659Chronakis, I. S., Grapenson, S., & Jakob, A. (2006). Conductive polypyrrole nanofibers via electrospinning: Electrical and morphological properties. Poly

BDNF-Gene Transfected Schwann Cell-Assisted Axonal Extension and Sprouting on New PLA-PPy Microfiber Substrates

[EN] The work here reported analyzes the effect of increased efficiency of brainderived neurotrophic factor (BDNF) production by electroporated Schwann cells (SCs) on the axonal extension in a coculture system on a biomaterial platform that can be of interest for the treatment of injuries of the nervous system, both central and peripheral. Rat SCs are electrotransfected with a plasmid coding for the BDNF protein in order to achieve an increased expression and release of this protein into the culture medium of the cells, performing the best balance between the level of transfection and the number of living cells. Gene-transfected SCs show an about 100-fold increase in the release of BDNF into the culture medium, compared to nonelectroporated SCs. Cocultivation of electroporated SCs with rat dorsal root ganglia (DRG) is performed on highly aligned substrates of polylactic acid (PLA) microfibers coated with the electroconductive polymer polypyrrol (PPy). The coculture of DRG with electrotransfected SCs increase both the axonal extension and the axonal sprouting from DRG neurons compared to the coculture of DRG with nonelectroporated SCs. Therefore, the use of PLA¿PPy highly aligned microfiber substrates preseeded with electrotransfected SCs with an increased BDNF secretion is capable of both guiding and accelerating axonal growth.The authors acknowledge financial support from the Spanish Government's State Research Agency (AEI) through projects DPI2015-72863-EXP and RTI2018-095872-B-C22/ERDF. F.G.R. acknowledges the scholarship FPU16/01833 and the short stay mobility aid EST18/00524 of the Spanish Ministry of Universities. F.G.R. also acknowledges the hosting at the Vectorology and Anti-cancer Therapies Centre (UMR 8203 CNRS). The authors thank the Electron Microscopy Service at the UPV, where the FESEM images were obtained.Gisbert-Roca, F.; André, FM.; Más Estellés, J.; Monleón Pradas, M.; Mir, LM.; Martínez-Ramos, C. (2021). BDNF-Gene Transfected Schwann Cell-Assisted Axonal Extension and Sprouting on New PLA-PPy Microfiber Substrates. Macromolecular Bioscience (Online). 21(5):1-13. https://doi.org/10.1002/mabi.202000391S11321

CD44-negative parietal–epithelial cell staining in minimal change disease: association with clinical features, response to corticosteroids and kidney outcome

Idiopathic nephrotic syndrome; Minimal change disease; Parietal–epithelial cellsSíndrome nefrótico idiopático; Enfermedad de cambios mínimos; Células parietales-epitelialesSíndrome nefròtica idiopàtica; Malaltia de canvis mínims; Cèl·lules parietals-epitelialsBackground Activation of parietal–epithelial cells (PECs) with neo-expression of CD44 has been found to play a relevant role in the development of focal and segmental glomerulosclerosis (FSGS). The aim of this study was to analyse whether the expression of CD44 by PECs in biopsies of minimal change disease (MCD) is associated with the response to corticosteroids, with kidney outcomes and/or can be considered an early sign of FSGS. Methods This multicentric, retrospective study included paediatric and adult patients with MCD. Demographic, clinical and biochemical data were recorded, and biopsies were stained with anti-CD44 antibodies. The association between PECs, CD44 expression and the response to corticosteroids, and kidney outcomes were analysed using logistic, Kaplan–Meier and Cox regression analyses. Results A total of 54 patients were included: 35 (65%) <18 years and 19 (35%) adults. Mean follow-up was 68.3 ± 37.9 months. A total of 19/54 patients (35.2%) showed CD44-positive staining. CD44-positive patients were younger (14.5 ± 5 versus 21.5 ± 13, P = 0.006), and showed a higher incidence of steroid-resistance [11/19 (57.8%) versus 7/35 (20%), P = 0.021; odds ratio: 5.5 (95% confidence interval 1.6–18), P = 0.007] and chronic kidney disease [9/19 (47.3%) versus 6/35 (17.1%), P = 0.021; relative risk: 3.01 (95% confidence interval 1.07–8.5), P = 0.037]. Follow-up re-biopsies of native kidneys (n = 18), identified FSGS lesions in 10/12 (83.3%) of first-biopsy CD44-positive patients versus 1/6 (16.7%) of first-biopsy CD44-negative patients (P = 0.026). Conclusions In patients with a light microscopy pattern of MCD, CD44-positive staining of PECs is associated with a higher prevalence of steroid resistance and worse kidney outcomes, and can be considered an early sign of FSGS.C.M. is supported by a Miguel Servet grant, Fondo de investigación sanitaria, Instituto de Salud Carlos III, Ministerio de Ciencia, Innovacio´n y Universidades [CP18/00116]. No additional funding was required for the current study

Conduits based on the combination of hyaluronic acid and silk fibroin: Characterization, in vitro studies and in vivo biocompatibility

[EN] We address the production of structures intended as conduits made from natural biopolymers, capable of promoting the regeneration of axonal tracts. We combine hyaluronic acid (HA) and silk fibroin (SF) with the aim of improving mechanical and biological properties of HA. The results show that SF can be efficiently incorporated into the production process, obtaining conduits with tubular structure with a matrix of HA-SF blend. HA-SF has better mechanical properties than sole HA, which is a very soft hydrogel, facilitating manipulation. Culture of rat Schwann cells shows that cell adhesion and proliferation are higher than in pure HA, maybe due to the binding motifs contributed by the SF protein. This increased proliferation accelerates the formation of a tight cell layer, which covers the inner channel surface of the HA-SF tubes. Biocompatibility of the scaffolds was studied in immunocompetent mice. Both HA and HA-SF scaffolds were accepted by the host with no residual immune response at 8 weeks. New collagen extracellular matrix and new blood vessels were visible and they were present earlier when SF was present. The results show that incorporation of SF enhances the mechanical properties of the materials and results in promising biocompatible conduits for tubulization strategies.The authors acknowledge financing from the Spanish Ministry of Economy and Competitiveness through grants RTI2018-095872-B-C22/ERDF, DPI2015-72863-EXP, MAT2016-79832-R, MAT2016-76847-R and Community of Madrid through grant Neurocentro-B2017/BMD-3760. FGR acknowledges scholarship FPU16/01833 of the Spanish Ministry of Education, Culture and Sports. We thank the Electron Microscopy Service at the UPV, where the FESEM images were obtainedGisbert-Roca, F.; Lozano Picazo, P.; Pérez-Rigueiro, J.; Guinea Tortuero, GV.; Monleón Pradas, M.; Martínez-Ramos, C. (2020). Conduits based on the combination of hyaluronic acid and silk fibroin: Characterization, in vitro studies and in vivo biocompatibility. International Journal of Biological Macromolecules. 148:378-390. https://doi.org/10.1016/j.ijbiomac.2020.01.149S378390148Fawcett, J. W., & Asher, R. . (1999). The glial scar and central nervous system repair. Brain Research Bulletin, 49(6), 377-391. doi:10.1016/s0361-9230(99)00072-6Koeppen, A. H. (2004). Wallerian degeneration: history and clinical significance. Journal of the Neurological Sciences, 220(1-2), 115-117. doi:10.1016/j.jns.2004.03.008Hall, S. (2005). The response to injury in the peripheral nervous system. The Journal of Bone and Joint Surgery. British volume, 87-B(10), 1309-1319. doi:10.1302/0301-620x.87b10.16700Dubový, P., Klusáková, I., & Hradilová Svíženská, I. (2014). Inflammatory Profiling of Schwann Cells in Contact with Growing Axons Distal to Nerve Injury. BioMed Research International, 2014, 1-7. doi:10.1155/2014/691041Houschyar, K. S., Momeni, A., Pyles, M. N., Cha, J. Y., Maan, Z. N., Duscher, D., … Schoonhoven, J. van. (2016). The Role of Current Techniques and Concepts in Peripheral Nerve Repair. Plastic Surgery International, 2016, 1-8. doi:10.1155/2016/4175293Tian, L., Prabhakaran, M. P., & Ramakrishna, S. (2015). Strategies for regeneration of components of nervous system: scaffolds, cells and biomolecules. Regenerative Biomaterials, 2(1), 31-45. doi:10.1093/rb/rbu017Kehoe, S., Zhang, X. F., & Boyd, D. (2012). FDA approved guidance conduits and wraps for peripheral nerve injury: A review of materials and efficacy. Injury, 43(5), 553-572. doi:10.1016/j.injury.2010.12.030Collins, M. N., & Birkinshaw, C. (2013). Hyaluronic acid based scaffolds for tissue engineering—A review. Carbohydrate Polymers, 92(2), 1262-1279. doi:10.1016/j.carbpol.2012.10.028Cowman, M. K., & Matsuoka, S. (2005). Experimental approaches to hyaluronan structure. Carbohydrate Research, 340(5), 791-809. doi:10.1016/j.carres.2005.01.022Liang, Y., Walczak, P., & Bulte, J. W. M. (2013). The survival of engrafted neural stem cells within hyaluronic acid hydrogels. Biomaterials, 34(22), 5521-5529. doi:10.1016/j.biomaterials.2013.03.095Wang, T.-W., & Spector, M. (2009). Development of hyaluronic acid-based scaffolds for brain tissue engineering. Acta Biomaterialia, 5(7), 2371-2384. doi:10.1016/j.actbio.2009.03.033Ma, J., Tian, W.-M., Hou, S.-P., Xu, Q.-Y., Spector, M., & Cui, F.-Z. (2007). An experimental test of stroke recovery by implanting a hyaluronic acid hydrogel carrying a Nogo receptor antibody in a rat model. Biomedical Materials, 2(4), 233-240. doi:10.1088/1748-6041/2/4/005Tian, W. M., Hou, S. P., Ma, J., Zhang, C. L., Xu, Q. Y., Lee, I. S., … Cui, F. Z. (2005). Hyaluronic Acid–Poly-D-Lysine-Based Three-Dimensional Hydrogel for Traumatic Brain Injury. Tissue Engineering, 11(3-4), 513-525. doi:10.1089/ten.2005.11.513Vilariño-Feltrer, G., Martínez-Ramos, C., Monleón-de-la-Fuente, A., Vallés-Lluch, A., Moratal, D., Barcia Albacar, J. A., & Monleón Pradas, M. (2016). Schwann-cell cylinders grown inside hyaluronic-acid tubular scaffolds with gradient porosity. Acta Biomaterialia, 30, 199-211. doi:10.1016/j.actbio.2015.10.040Ortuño-Lizarán, I., Vilariño-Feltrer, G., Martínez-Ramos, C., Pradas, M. M., & Vallés-Lluch, A. (2016). Influence of synthesis parameters on hyaluronic acid hydrogels intended as nerve conduits. Biofabrication, 8(4), 045011. doi:10.1088/1758-5090/8/4/045011Vepari, C., & Kaplan, D. L. (2007). Silk as a biomaterial. Progress in Polymer Science, 32(8-9), 991-1007. doi:10.1016/j.progpolymsci.2007.05.013Murphy, A. R., & Kaplan, D. L. (2009). Biomedical applications of chemically-modified silk fibroin. Journal of Materials Chemistry, 19(36), 6443. doi:10.1039/b905802hSofia, S., McCarthy, M. B., Gronowicz, G., & Kaplan, D. L. (2000). Functionalized silk-based biomaterials for bone formation. Journal of Biomedical Materials Research, 54(1), 139-148. doi:10.1002/1097-4636(200101)54:13.0.co;2-7Altman, G. H., Diaz, F., Jakuba, C., Calabro, T., Horan, R. L., Chen, J., … Kaplan, D. L. (2003). Silk-based biomaterials. Biomaterials, 24(3), 401-416. doi:10.1016/s0142-9612(02)00353-8Horan, R. L., Antle, K., Collette, A. L., Wang, Y., Huang, J., Moreau, J. E., … Altman, G. H. (2005). In vitro degradation of silk fibroin. Biomaterials, 26(17), 3385-3393. doi:10.1016/j.biomaterials.2004.09.020Chi, N.-H., Yang, M.-C., Chung, T.-W., Chou, N.-K., & Wang, S.-S. (2013). Cardiac repair using chitosan-hyaluronan/silk fibroin patches in a rat heart model with myocardial infarction. Carbohydrate Polymers, 92(1), 591-597. doi:10.1016/j.carbpol.2012.09.012Chi, N.-H., Yang, M.-C., Chung, T.-W., Chen, J.-Y., Chou, N.-K., & Wang, S.-S. (2012). Cardiac repair achieved by bone marrow mesenchymal stem cells/silk fibroin/hyaluronic acid patches in a rat of myocardial infarction model. Biomaterials, 33(22), 5541-5551. doi:10.1016/j.biomaterials.2012.04.030Yang, M.-C., Chi, N.-H., Chou, N.-K., Huang, Y.-Y., Chung, T.-W., Chang, Y.-L., … Wang, S.-S. (2010). The influence of rat mesenchymal stem cell CD44 surface markers on cell growth, fibronectin expression, and cardiomyogenic differentiation on silk fibroin – Hyaluronic acid cardiac patches. Biomaterials, 31(5), 854-862. doi:10.1016/j.biomaterials.2009.09.096Zhou, J., Zhang, B., Liu, X., Shi, L., Zhu, J., Wei, D., … He, D. (2016). Facile method to prepare silk fibroin/hyaluronic acid films for vascular endothelial growth factor release. Carbohydrate Polymers, 143, 301-309. doi:10.1016/j.carbpol.2016.01.023Yan, S., Li, M., Zhang, Q., & Wang, J. (2013). Blend films based on silk fibroin/hyaluronic acid. Fibers and Polymers, 14(2), 188-194. doi:10.1007/s12221-013-0188-2Foss, C., Merzari, E., Migliaresi, C., & Motta, A. (2012). Silk Fibroin/Hyaluronic Acid 3D Matrices for Cartilage Tissue Engineering. Biomacromolecules, 14(1), 38-47. doi:10.1021/bm301174xJaipaew, J., Wangkulangkul, P., Meesane, J., Raungrut, P., & Puttawibul, P. (2016). Mimicked cartilage scaffolds of silk fibroin/hyaluronic acid with stem cells for osteoarthritis surgery: Morphological, mechanical, and physical clues. Materials Science and Engineering: C, 64, 173-182. doi:10.1016/j.msec.2016.03.063Fan, Z., Zhang, F., Liu, T., & Zuo, B. Q. (2014). Effect of hyaluronan molecular weight on structure and biocompatibility of silk fibroin/hyaluronan scaffolds. International Journal of Biological Macromolecules, 65, 516-523. doi:10.1016/j.ijbiomac.2014.01.058Chung, T.-W., & Chang, Y.-L. (2010). Silk fibroin/chitosan–hyaluronic acid versus silk fibroin scaffolds for tissue engineering: promoting cell proliferations in vitro. Journal of Materials Science: Materials in Medicine, 21(4), 1343-1351. doi:10.1007/s10856-009-3876-0Garcia-Fuentes, M., Meinel, A. J., Hilbe, M., Meinel, L., & Merkle, H. P. (2009). Silk fibroin/hyaluronan scaffolds for human mesenchymal stem cell culture in tissue engineering. Biomaterials, 30(28), 5068-5076. doi:10.1016/j.biomaterials.2009.06.008Raia, N. R., Partlow, B. P., McGill, M., Kimmerling, E. P., Ghezzi, C. E., & Kaplan, D. L. (2017). Enzymatically crosslinked silk-hyaluronic acid hydrogels. Biomaterials, 131, 58-67. doi:10.1016/j.biomaterials.2017.03.046Yan, S., Zhang, Q., Wang, J., Liu, Y., Lu, S., Li, M., & Kaplan, D. L. (2013). Silk fibroin/chondroitin sulfate/hyaluronic acid ternary scaffolds for dermal tissue reconstruction. Acta Biomaterialia, 9(6), 6771-6782. doi:10.1016/j.actbio.2013.02.016Garcia-Fuentes, M., Giger, E., Meinel, L., & Merkle, H. P. (2008). The effect of hyaluronic acid on silk fibroin conformation. Biomaterials, 29(6), 633-642. doi:10.1016/j.biomaterials.2007.10.024Hu, X., Lu, Q., Sun, L., Cebe, P., Wang, X., Zhang, X., & Kaplan, D. L. (2010). Biomaterials from Ultrasonication-Induced Silk Fibroin−Hyaluronic Acid Hydrogels. Biomacromolecules, 11(11), 3178-3188. doi:10.1021/bm1010504Ren, Y.-J., Zhou, Z.-Y., Liu, B.-F., Xu, Q.-Y., & Cui, F.-Z. (2009). Preparation and characterization of fibroin/hyaluronic acid composite scaffold. International Journal of Biological Macromolecules, 44(4), 372-378. doi:10.1016/j.ijbiomac.2009.02.004Cazzaniga, A., Ballin, A., & Brandt, F. (2008). Hyaluronic acid gel fillers in the management of facial aging. Clinical Interventions in Aging, Volume 3, 153-159. doi:10.2147/cia.s2135Sun, S.-F., Chou, Y.-J., Hsu, C.-W., & Chen, W.-L. (2009). Hyaluronic acid as a treatment for ankle osteoarthritis. Current Reviews in Musculoskeletal Medicine, 2(2), 78-82. doi:10.1007/s12178-009-9048-5Yucel, T., Lovett, M. L., & Kaplan, D. L. (2014). Silk-based biomaterials for sustained drug delivery. Journal of Controlled Release, 190, 381-397. doi:10.1016/j.jconrel.2014.05.059Bettinger, C. J., Cyr, K. M., Matsumoto, A., Langer, R., Borenstein, J. T., & Kaplan, D. L. (2007). Silk Fibroin Microfluidic Devices. Advanced Materials, 19(19), 2847-2850. doi:10.1002/adma.200602487Schindelin, J., Arganda-Carreras, I., Frise, E., Kaynig, V., Longair, M., Pietzsch, T., … Cardona, A. (2012). Fiji: an open-source platform for biological-image analysis. Nature Methods, 9(7), 676-682. doi:10.1038/nmeth.2019Taddei, P., Pavoni, E., & Tsukada, M. (2016). Stability toward alkaline hydrolysis ofB.morisilk fibroin grafted with methacrylamide. Journal of Raman Spectroscopy, 47(6), 731-739. doi:10.1002/jrs.4892Perea, G. B., Solanas, C., Marí-Buyé, N., Madurga, R., Agulló-Rueda, F., Muinelo, A., … Pérez-Rigueiro, J. (2016). The apparent variability of silkworm ( Bombyx mori ) silk and its relationship with degumming. European Polymer Journal, 78, 129-140. doi:10.1016/j.eurpolymj.2016.03.012Hu, M., Sabelman, E. E., Tsai, C., Tan, J., & Hentz, V. R. (2000). Improvement of Schwann Cell Attachment and Proliferation on Modified Hyaluronic Acid Strands by Polylysine. Tissue Engineering, 6(6), 585-593. doi:10.1089/10763270050199532Monteiro, G. A., Fernandes, A. V., Sundararaghavan, H. G., & Shreiber, D. I. (2011). Positively and Negatively Modulating Cell Adhesion to Type I Collagen Via Peptide Grafting. Tissue Engineering Part A, 17(13-14), 1663-1673. doi:10.1089/ten.tea.2008.0346Ude, A. U., Eshkoor, R. A., Zulkifili, R., Ariffin, A. K., Dzuraidah, A. W., & Azhari, C. H. (2014). Bombyx mori silk fibre and its composite: A review of contemporary developments. Materials & Design, 57, 298-305. doi:10.1016/j.matdes.2013.12.052Atkins, E. D. T., Phelps, C. F., & Sheehan, J. K. (1972). The conformation of the mucopolysaccharides. Hyaluronates. Biochemical Journal, 128(5), 1255-1263. doi:10.1042/bj128125

Alginate-Agarose Hydrogels Improve the In Vitro Differentiation of Human Dental Pulp Stem Cells in Chondrocytes. A Histological Study

[EN] Matrix-assisted autologous chondrocyte implantation (MACI) has shown promising results for cartilage repair, combining cultured chondrocytes and hydrogels, including alginate. The ability of chondrocytes for MACI is limited by different factors including donor site morbidity, dedifferentiation, limited lifespan or poor proliferation in vitro. Mesenchymal stem cells could represent an alternative for cartilage regeneration. In this study, we propose a MACI scaffold consisting of a mixed alginate-agarose hydrogel in combination with human dental pulp stem cells (hDPSCs), suitable for cartilage regeneration. Scaffolds were characterized according to their rheological properties, and their histomorphometric and molecular biology results. Agarose significantly improved the biomechanical behavior of the alginate scaffolds. Large scaffolds were manufactured, and a homogeneous distribution of cells was observed within them. Although primary chondrocytes showed a greater capacity for chondrogenic differentiation, hDPSCs cultured in the scaffolds formed large aggregates of cells, acquired a rounded morphology and expressed high amounts of type II collagen and aggrecan. Cells cultured in the scaffolds expressed not only chondral matrix-related genes, but also remodeling proteins and chondrocyte differentiation factors. The degree of differentiation of cells was proportional to the number and size of the cell aggregates that were formed in the hydrogels.This work was funded by the Ministry of Economy and Competitiveness of the Spanish Government (PID2019-106099RB-C42, MM) and by the Generalitat Valenciana, Spain (PROMETEO/2020/069, CC). CIBER-BBN and CIBER-ER are financed by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and the Instituto de Salud Carlos III, with assistance of the European Regional Development Fund.Oliver-Ferrándiz, M.; Milián, L.; Sancho-Tello, M.; Martín De Llano, JJ.; Gisbert-Roca, F.; Martínez-Ramos, C.; Carda, C.... (2021). Alginate-Agarose Hydrogels Improve the In Vitro Differentiation of Human Dental Pulp Stem Cells in Chondrocytes. A Histological Study. Biomedicines. 9(7):1-22. https://doi.org/10.3390/biomedicines9070834S1229

Predictors of Loss of Functional Independence in Parkinson’s Disease: Results from the COPPADIS Cohort at 2-Year Follow-Up and Comparison with a Control Group

Enfermedad de Parkinson; Dependencia; DiscapacidadMalaltia de Parkinson; Dependència; DiscapacitatParkinson’s disease; Dependency; DisabilityBackground and objective: The aim of this study was to compare the progression of independence in activities of daily living (ADL) in Parkinson’s disease (PD) patients versus a control group, as well as to identify predictors of disability progression and functional dependency (FD). Patients and Methods: PD patients and control subjects, who were recruited from 35 centers of Spain from the COPPADIS cohort between January 2016 and November 2017 (V0), were included. Patients and subjects were then evaluated again at the 2-year follow-up (V2). Disability was assessed with the Schwab & England Activities of Daily Living Scale (S&E-ADLS) at V0 and V2. FD was defined as an S&E-ADLS score less than 80%. Results: In the PD group, a significant decrease in the S&E-ADLS score from V0 to V2 (N = 507; from 88.58 ± 10.19 to 84.26 ± 13.38; p < 0.0001; Cohen’s effect size = −0.519) was observed but not in controls (N = 124; from 98.87 ± 6.52 to 99.52 ± 2.15; p = 0.238). When only patients considered functional independent at baseline were included, 55 out of 463 (11.9%) converted to functional dependent at V2. To be a female (OR = 2.908; p = 0.009), have longer disease duration (OR = 1.152; p = 0.002), have a non-tremoric motor phenotype at baseline (OR = 3.574; p = 0.004), have a higher score at baseline in FOGQ (OR = 1.244; p < 0.0001) and BDI-II (OR = 1.080; p = 0.008), have a lower score at baseline in PD-CRS (OR = 0.963; p = 0.008), and have a greater increase in the score from V0 to V2 in UPDRS-IV (OR = 1.168; p = 0.0.29), FOGQ (OR = 1.348; p < 0.0001) and VAFS-Mental (OR = 1.177; p = 0.013) (adjusted R-squared 0.52; Hosmer and Lemeshow test = 0.94) were all found to be independent predictors of FD at V2. Conclusions: In conclusion, autonomy for ADL worsens in PD patients compared to controls. Cognitive impairment, gait problems, fatigue, depressive symptoms, more advanced disease, and a non-tremor phenotype are independent predictors of FD in the short-term.Fundación Curemos el Parkinso

Integrated Care Intervention Supported by a Mobile Health Tool for Patients Using Noninvasive Ventilation at Home: Randomized Controlled Trial

Background: Home-based noninvasive ventilation has proven cost-effective. But, adherence to therapy still constitutes a common clinical problem. We hypothesized that a behavioral intervention supported by a mobile health (mHealth) app could enhance patient self-efficacy. It is widely accepted that mHealth-supported services can enhance productive interactions among the stakeholders involved in home-based respiratory therapies. Objective: This study aimed to measure changes in self-efficacy in patients with chronic respiratory failure due to diverse etiologies during a 3-month follow-up period after the intervention. Ancillary objectives were assessment of usability and acceptability of the mobile app as well as its potential contribution to collaborative work among stakeholders. Methods: A single-blind, single-center, randomized controlled trial was conducted between February 2019 and June 2019 with 67 adult patients with chronic respiratory failure undergoing home-based noninvasive ventilation. In the intervention group, a psychologist delivered a face-to-face motivational intervention. Follow-up was supported by a mobile app that allowed patients to report the number of hours of daily noninvasive ventilation use and problems with the therapy. Advice was automatically delivered by the mobile app in case of a reported problem. The control group received usual care. The primary outcome was the change in the Self Efficacy in Sleep Apnea questionnaire score. Secondary outcomes included app usability, app acceptability, continuity of care, person-centered care, and ventilatory parameters. Results: Self-efficacy was not significantly different in the intervention group after the intervention (before: mean 3.4, SD 0.6; after: mean 3.4, SD 0.5, P=.51). No changes were observed in adherence to therapy nor quality of life. Overall, the mHealth tool had a good usability score (mean 78 points) and high acceptance rate (mean score of 7.5/10 on a Likert scale). It was considered user-friendly (mean score of 8.2/10 on a Likert scale) and easy to use without assistance (mean score of 8.5/10 on a Likert scale). Patients also scored the perception of continuity of care and person-centered care as high. Conclusions: The integrated care intervention supported by the mobile app did not improve patient self-management. However, the high acceptance of the mobile app might indicate potential for enhanced communication among stakeholders. The study identified key elements required for mHealth tools to provide effective support to collaborative work and personalized care