This study examines the prospects of using the electrospinning process to fabricate tissue engineering scaffolds targeting a variety of regenerative applications, with a primary focus on the production of nerve guides for the treatment of long-defect nerve injuries in the peripheral nervous system. A basic overview of the conventional electrospinning process is provided, and the utility of this fabrication scheme in the production of collagen-based tissue engineering scaffolds is demonstrated. Next, a novel modification of the basic electrospinning process is presented. This process, called two pole air gap electrospinning, was developed to produce nerve guides that exhibit an anisotropic structure that mimics the extracellular matrix of native peripheral nerve tissue. This electrospinning process makes it possible to produce macroscopic nerve guides that are cylindrical in shape and composed of dense arrays of nano- to micron-scale diameter fibers. Unlike, conventional hollow core nerve guides, these electrospun constructs lack a central lumen, hence the designation 3D (for three-dimensional) nerve guide. The fibers are nearly exclusively arrayed in parallel with the long axis of the construct. This architectural feature provides thousands of individual channels, and aligned fibers that provide guidance cues that are designed to drive regenerating axons to grow in a highly directed fashion down the longitudinal axis of the guide. To supplement the structural cues provided by the fibrillar arrays of the electrospun 3D nerve guides, an alginate-based platform designed to deliver therapeutic reagents was developed and characterized. This platform makes it possible to fabricate gradients of therapeutic reagents within the fibrillar arrays of an electrospun nerve guide. Functional and structural analyses of these constructs supplemented with or without a gradient of NGF, in a long-defect nerve injury in the rodent sciatic nerve indicate that the 3D design is superior to the gold standard treatment, the autologous nerve graft. Animals treated with the 3D grafts recovered motor and sensory function faster and exhibited far higher nerve-to-nerve and nerve-to-muscle signal amplitudes in electrophysiological studies than animals treated with autologous grafts or conventional hollow core cylindrical grafts.

Sulfatide is a galactolipid and a major lipid component of the myelin sheath. Its production is catalyzed by the enzyme cerebroside sulfotransferase (CST). To determine the functions of sulfatide, the gene encoding CST was genetically disrupted resulting in mice incapable of sulfatide synthesis. Using these mice, it has been shown in the central nervous system (CNS) that sulfatide is essential for normal myelin synthesis and stability even though the onset of myelination is not impaired. Additionally, proper initial clustering of paranodal proteins and cluster maintenance of nodal proteins is impaired suggesting that paranodal domains are important for long-term node stability. In contrast to the CNS, a requirement for sulfatide in the initiation of myelination, and in initiation of paranodal and nodal clustering or in the long-term maintenance of these clusters in the peripheral nervous system (PNS) has not been analyzed. Therefore, we have employed a combination of electron microscopic, immunocytochemical, and confocal microscopic analyses of the CST KO mice to determine the role of sulfatide in PNS myelination and onset of protein domain formation and maintenance. For these studies we have quantified myelin thickness, paranodal structural integrity, and the number of paranodal and nodal protein clusters in the CST KO and wild type mice at 4 days, 7 days, and 10 months of age. Our findings indicate that myelination onset is not delayed in the absence of sulfatide and that both the node and paranode are grossly normal; however, closer analysis reveals that paranodal junctions are compromised, Schwann cell microvilli are disoriented and the myelin-axon interface along the internodal region is transiently disrupted. In addition, we report that the paranodal myelin protein neurofascin 155 (Nfasc155) shows a transient decrease in initial clustering in the CST null mice at 4 days of age that is restored to WT levels by 7 days of age that is also maintained in the adult mice. Whereas nodal clustering of neuronal voltage-gated sodium channels is initially normal, cluster number is significantly but also transiently reduced by 7 days of age. By 10 months of age, the number of sodium channel clusters is restored to normal levels. In contrast, clustering of neither the paranodal neuronal protein contactin nor the myelin nodal protein gliomedin is altered at any of the ages studied. Together our findings suggest that sulfatide is not essential for PNS myelination or for protein domain formation in contrast to its more vital role in the development and maintenance of the CNS.

3 domaines cellulaires définissent l'épiderme de la queue de Ciona intestinalis. Le domaine des lignes médianes, donne naissance à deux structures différenciées larvaires, la nageoire et système nerveux périphérique. Il a été montré que les voies de signalisation BMP et FGF sont respectivement les inducteurs des lignes médianes ventrale et dorsale. Ce travail a consisté en la caractérisation des mécanismes moléculaires, situés à l'interface des signaux inducteurs et des processus de différenciation, définissant l'identité cellulaire des lignes médianes. L'identification des relations épistatiques reliant 7 facteurs de transcription impliqués dans ce processus suggère un fonctionnement en réseau hiérarchisé et place Msxb comme gène clé. Cette hiérarchie est validée par: un atlas d'expression spatio-temporelle, la perte de fonction de Msxb, l'analyse des régions cis-régulatrices de la transcription. Nous avons identifié 2 types d'enhancers, contrôlant respectivement les gènes précoces et tardifs du réseau. L'expression précoce de Msxb dans les précurseurs dorsaux est controlée par un enhancer distinct régulé par la voie FGF relayée par Otx et Nodal. Cette signature transcriptionnelle est retrouvée dans les enhancers de gènes co-exprimés, et chez l'orthologue de Msxb chez une autre ascidie. Enfin, nous montrons que la partie la plus postérieure des lignes médianes constitue un troisième compartiment, déployant un programme génétique distinct. Ce travail nous renseigne sur la structure, les mécanismes moléculaires de formation des lignes médianes, l'existence d'une signature transcriptionnelle évolutivement conservée pour le gène clé de l'acquisition de ce destin cellulaire. / Ciona intestinalis tail epidermis has 8 rows of cells defining 3 domains. One of them, the midline domain, gives rise to differentiated cells which form the larval fin and part of peripheral nervous system. Previous work has shown that BMP and FGF signalling are the inducers of ventral and dorsal midlines respectively. My work consisted in the identification of molecular events which lead epidermal cells to adopt midline fate, from induction to tail differentiation. We identified 7 transcription factors involved in this process. Identification of epistatic relationships suggest that these genes are in a hierarchical network where Msxb is a key gene. This hierarchy is validated by 1) a spatio-temporal expression atlas, 2) loss of function of Msxb, 3) cis-regulatory regions analysis for each network gene. We identified 2 types of enhancers, one capable to decouple ventral / dorsal signals used by early genes, and the other used by later genes, acting as a global response in both midlines. We showed that the early expression of Msxb in dorsal precursors is controled by a distinct enhancer, regulated by FGF9/16/20 via Otx and Nodal. This transcriptional signature is found in enhancers of co-expressed genes and in Msxb orthologue in another ascidian. Finally, we showed the most posterior part of the midlines is controlled by a distinct genetic program than the one used in dorsal and ventral midlines. This work gives insight into midlines structure, the mechanisms involved in their formation and a conserved transcriptional signature for the key gene involved in midline cell fate.

Foi estudada a ação do fator neurotrófico ciliar (CNTF) e da interleucina 6 (IL-6) exógenos na regeneração nervosa periférica. Aplicação de CNTF recombinante humano: o nervo ciático de 12 camundongos adultos C57BL/6J (3 grupos, n=4) foi seccionado e os cotos proximal e distal ancorados com ponto único de sutura no interior de tubo de polietileno (TP) com 6 mm d e comprimento e 0,76 mm de diâmetro interno, com intervalo de 4 mm entre os cotos. Os TP foram implantados vazios ou preenchidos com uma das seguintes soluções: (1) colágeno (col.) purificado (Vitrogen, 2,4 mg/ml) em tampão fosfato (0,2M), na proporção d e 1:1; (2) col.+CNTF (1:1, com 100 ng/ml de CNTF/tubo). Após 6 semanas os tubos contendo ao cabos nervosos regenerado s (CR) foram processados e incluídos em Epon. Fibras nervosas mielínicas foram contadas na porção média dos CR com um sistema controlado por computador (Biographics). Camundongos que receberam CNTF apresentaram número significativamente maior de axônios regenerados (3027±62, média±erro padrão) em relação aos animais implantados com tubos vazios (1384±128) ou preenchidos apenas com colágeno (1639±104). Outros 12 animais adicionais tiveram o nervo ciático seccionado e reparado da mesma maneira. Após 6 semanas, um tubo contendo solução do traçador neuronal HRP foi implantado no coto distal do nervo. Decorrido um período suplementar de 3 dias, neurônios marcados foram contados na medula espinhal e nos gânglios das raízes dorsais L4,5,6- Não houve diferença significante no número de motoneurônios entre os diferentes grupos experimentais (vazio=740±21; col.=749±44; CNTF=790±14) e o s animais não-operados (794±30). Não houve também diferença significante no número de neurônios sensitivos entre os diferentes grupos experimentais (vazio=1920±59; co!.=2262±152; CNTF=2124+96) e todos apresentaram número menor de neurônios sensitivos quando comparados com os animais não operados (4211+96) Aplicação de IL-6 recombinante murina: 12 camundongos C57BL/6J adultos foram divididos em dois grupos (n=6) e implantados com TP preenchidos com: (1) Vitrogen (2,4 mg/ml) e tampão fosfato (0,2 M), na proporção d e 1:1; (2) Vitrogen + IL-6 (1:1, com 100 |ig/ml de IL-6/tubo). Após tempo d e sobrevida de 6 semanas , os tubos com os CR foram processados da mesma forma que no experimento anterior. Fibras nervosas mielínicas foram contadas na porção média d o s CR. Os resultados mostraram que os animais implantados com col.+IL-6 tinham número significativamente maior de axônios mielínicos (2025+143) que os animais injetados apenas com col. (1542±122). O gânglio L5 foi também removido dos mesmos animais e cortado seriadamente (5|am), para posterior contagem do número de neurônios sensitivos. Não houve diferença significante no número de neurônios sensitivos entre os grupos experimentais (col.=528+42, col.+IL-6=554±37); todos, no entanto, apresentaram número significantemente menor de neurônios sensitivos quando comparados com os animais não operados (1112+63). Esses resultados indicam que a aplicação local de CNTF ou IL-6 estimula a regeneração de nervos seccionados e que este efeito é devido, provavelmente, a um aumento da taxa de brotamento dos axônios em regeneração / We studied the actions of exogenous ciliary neurotrophic factor (CNTF) and interleukin-6 (IL-6) on peripheral nerve regeneration. The sciatic nerve of 12 adult C57BL/6J mice (3 groups; n=4) w a s transected and both proximal and distal nerve stumps were secured by a single 10-0 suture into a 6-mm of a polyethylene tube (PT) (0,76 mm ID) to give a final gap length of 4mm. The PT were implanted empty or filled with one of the following solutions: (1) a purified preparation of collagen (Vitrogen, 2,4 mg/ml) plus phosphate buffer solution (0,2M), in 1:1 ratio; (2) Vitrogen + human recombinant CNTF (1:1, with 100 ng/ml of CNTF/tube). After 6 weeks the tubes containing the regenerated nerve cables (NC) were processed for Epon embedding. Myelinated nerve fibers were counted from the mid-portion of the cab les with a computer-controlled system (Biographics). CNTF injected mice regenerated significantly more myelinated axons (3027±62, mean±SEM) compared to the animals implanted with tubes left empty (1384±128) or filled with collagen alone (1639±104). Next, 12 additional animals had the sciatic nerve transected and repaired a s above. After 6 weeks, HRP was applied to the distal stump of the regenerated nerves and labeled neurons were counted in the spinal cord an d L4.5.6 dorsal root ganglia (DRG). No significant difference in the number of motoneurons was detected between the experimental (empty=740±21; collagen=749±44; CNTF=790±14) and non-operated (794±30) animals. No difference was also found in the n umber of labeled DRG neurons among the experimental groups (empty=1920±59; collagen=2262±152; CNTF=2124±96) and all had fewer labeled sensory neurons compared to the non-operated group (4211+96). For the IL-6 experiments, 12 C57BL/6J mice were divided into 2 groups (n=6) and implanted with PT filled with one of the following solutions: (1) Vitrogem (2,4 mg/ml) plus phosphate buffer solution (0,2 M), in 1:1 ratio; (2) Vitrogen + murine recombinant IL-6 (1:1, with 100 |ig/ml of IL-6/tube). Following a survival time of 6 weeks, the tubes with the regenerating nerve cables were processed for Epon embedding and myelinated nerve fiber counting. The results showed a significant difference in the number of myelinated axons between the collagen+IL-6 group (2025±143) and the collagen alone group (1542±122). The L5 DRG was also removed from the same mice, and serially sectioned (5^m) for sensory neuron counts. No significant difference was found in the number of DRG neurons between the experimental groups (collagen=528±42; collagen+IL-6=554±37). However, all had significantly fewer sensory neurons compared to the non-operated group (1112+63). These results indicate that locally applied CNTF and IL-6 stimulate peripheral nerve regeneration in adult animals, and that the effects are due to a neurite-promoting activity on axotomized neurons

Introdução: A Neuropatia auditiva/Dessincronia auditiva (NA) é um transtorno que foi identificado há apenas 20 anos, os pacientes que possuíam este transtorno eram diagnosticados como deficientes auditivos como conseqüência da falha no diagnóstico. Com o surgimento do registro das Emissões Otoacústicas e sua presença no repertório de testes de avaliação auditiva, foi possível ao clínico fazer o diagnóstico de NA. Assim sendo, é possível que alguns indivíduos que foram diagnosticados como portadores de uma perda auditiva neurossensorial, tivessem, na verdade, NA. Objetivos: O objetivo deste estudo foi caracterizar o tipo e grau da deficiência auditiva em uma população de deficientes auditivos da cidade de São Paulo; verificar a época da suspeita pelos pais da deficiência auditiva bem como do diagnóstico audiológico nestes indivíduos; identificar os participantes cujas avaliações comportamentais são incompatíveis com as avaliações eletrofisiológicas, visando identificar casos de Neuropatia Auditiva e realizar estudo qualitativo de casos dos participantes com incompatibilidade de respostas nas avaliações comportamentais e eletrofisiológicas. Método: Foram avaliados 89 deficientes auditivos de três escolas especiais da cidade de São Paulo e 11 do setor de Audiologia Educacional da Faculdade de Medicina da Universidade de São Paulo através de alguns testes audiológicos: imitanciometria, audiometria tonal limiar (ATL), emissões otoacústicas (EOA) e potencial evocado auditivo do tronco-encefálico (PEATE). Resultados: Dos 100 participantes deste estudo, 99% apresentaram uma deficiência auditiva do tipo neurossensorial e em 50% o grau predominante da deficiência auditiva foi profundo, um deles não conseguiu realizar a ATL. A média de idade da suspeita dos pais foi de 15,52 meses e o diagnóstico clínico foi de 25,07 meses, em todos os grupos a suspeita dos pais foi anterior ao diagnóstico. Apenas um participante apresentou avaliações comportamentais incompatíveis com as eletrofisiólogicas, todavia, no decorrer da pesquisa o quadro foi modificado, sendo que a flutuação da audição foi o fator mais marcante observado. Conclusões: Os resultados sugerem que a NA é um transtorno raro mesmo na população dos deficientes auditivos e alertam para a necessidade de acompanhar longitudinalmente os casos de suspeita do transtorno / Introduction: Auditory Neuropathy/Auditory Dys-synchrony (AN) is a disorder identified only 20 years ago. Due to diagnosis failure, patients with this disorder were diagnosed as hearing impaired. AN diagnosis was made possible upon the appearance of OAE\'s recordings and its presence in hearing evaluation battery. Therefore, it is possible that some individuals who have been diagnosed as suffering from sensorioneural hearing loss had indeed AN. Purpose: The purpose of this study was to characterize the type and degree of auditory impairment in a population of the hearing impaired in the city of São Paulo; to verify when parents had the suspicious of the hearing impairment and when was the audiological diagnosis done in these individuals; to identify the subjects whose behavioral evaluations are not compatible with the electrophysiological evaluations in order to identify Auditory Neuropathy events and carry out a qualitative study of the cases of subjects with incompatibility of responses in the behavioral and electrophysiological evaluations. Method: 89 hearing impaired individuals from three school for the deaf in the city of São Paulo, and 11 from the Educational Audiology Division of the Medicine School of the University of São Paulo were evaluated in some audiological tests: imitanciometry, audiometer evaluation (AE), otoacoustic emissions (OAE) and Auditory Brainstem Response (ABR). Results: Out of the 100 subjects in this study, 99% presented a sensorioneural hearing loss, and in 50% the predominant degree of auditory loss was profound, one of the subjects was not able to perform AE. The average age of parents suspicion was 15.52 months and the clinical diagnosis was 25.07 months, in all the groups the parents suspicion was prior to the formal diagnosis. Only one subject presented behavioral evaluations incompatible with the electrophysiological, however, in the course of the research the chart was changed, whereas the hearing fluctuation was the most remarkable factor observed. Conclusions: The results suggest that AN is a rare disorder even in the hearing impaired community and alert the need of long term follow up in the cases of suspected disorder

Les Neuropathies Périphériques Héréditaires (IPN) constituent l’une des causes les plus fréquentes de maladies neurologiques héréditaires. Parmi elles, la maladie de Charcot-Marie-Tooth (CMT), constitue le groupe plus large. Durant ma thèse, j’ai étudié les bases physiopathologiques de deux formes d’IPN.1)J’ai étudié CMT4H, une forme rare de CMT démyélinisante, à transmission autosomique récessive, due à des mutations dans FGD4, qui code la protéine FRABIN. J’ai ainsi validé trois partenaires de FRABIN impliqués dans la voie du trafic vésiculaire. J’ai mis au point un modèle de myélinisation in vitro, à partir de notre modèle murin de CMT4H qui m’a permis de mettre en évidence une implication de FRABIN dans le processus d’endocytose et une dérégulation de la voie NRG1/PI3K/AKT. Dans une perspective thérapeutique, j’ai pu corriger ces défauts en ciblant la voie NRG1typeIII, par la niacine, un médicament approuvé par la FDA connu pour inhiber la myélinisation.2)Par séquençage de l’exome entier dans une famille d’origine libanaise présentant deux patients atteints d’une forme motrice d’IPN, associée à une atteinte centrale, nous avons identifié deux nouvelles mutations hétérozygotes composites dans le gène VRK1 qui code une protéine kinase nucléaire qui phosphoryle plusieurs facteurs de transcription. Des mutations dans VRK1 ont été décrites dans plusieurs maladies neurologiques, affectant les motoneurones. Des études fonctionnelles dans des lignées cellulaires issues de patients ont montré la pathogénicité de ces mutations et j’ai pu mettre en évidence pour la première fois, l’implication de la machinerie de transcription et d’épissage dans une pathologie associée à VRK1. / Inherited Peripheral Neuropathies (IPNs) are one of the most common causes of inherited neurological diseases. Among them, Charcot-Marie-Tooth disease (CMT) or Hereditary Motor and Sensory Neuropathy (HMSN), forms the largest group. During my thesis, I have studied the pathophysiological bases of two forms of IPNs.1) CMT4H, a rare form of autosomal recessive (AR) demyelinating CMT, due to mutations in FGD4 encoding FRABIN. First, I validated three partners of FRABIN involved in the vesicular trafficking pathway. I have also set up an in vitro myelination model based on the co-culture of DRG (Dorsal Root Ganglion) sensory neurons and Schwann cells (SCs) from our CMT4H mouse model. Studying this model allowed me to detect an upregulation of the NRG1 type III/PI3K/AKT pathway, which positively regulates myelination; and signs of impaired endocytosis, which presumably lead to the observed anomalies. I was able to correct these defects by targeting the NRG1 type III pathway with niacin, a FDA approved drug, known to downregulate NRG1-III signaling. 2) We have identified, by Whole Exome Sequencing two new compound heterozygous mutations in VRK1, in two siblings from a Lebanese family affected with distal Hereditary Motor Neuropathy associated with upper motor neurons signs. VRK1 is a nuclear kinase described to phosphorylate many transcription factors and for which mutations have been described in several motor neurons diseases. Functional studies on patients’ cells allowed me to demonstrate the pathogenicity of mutations and we brought evidence, for the first, about the implication of transcriptional machinery in a pathology associated to VRK1.

nÃo hà / IntroduÃÃo: A neurotoxicidade cumulativa à uma toxicidade que pode advir da terapia à base de oxaliplatina (OXL), que à a 3 geraÃÃo de agentes platinos com amplo espectro de atividade antitumoral, incluindo cÃncer colorretal, ovariano e pulmonar. A neurotoxicidade associada à OXL gera uma toxicidade dose-limitante, crÃnica, a neuropatia sensitiva perifÃrica (NSP). Objetivo: Investigar o envolvimento da endotelina-1, de receptores TRPV1 e NMDA e da substÃncia P envolvidos na patogÃnese da neuropatia sensitiva perifÃrica induzida pelo agente antineoplÃsico oxaliplatina. Materiais e mÃtodos: O estudo foi aprovado pelo Comità de Ãtica em Pesquisa Animal da UFC (protocolo n 75/12). Camundongos Swiss machos (20g) foram prÃ-tratados com antagonistas de receptores de endotelina-1 (Bosentana 100mg/kg, VO; BQ-123 e BQ-788 30Âl, intraplantar) e antagonistas do receptor TRPV1 (capsazepina, 5mg/kg, IP), antagonista do receptor NK-1 da Substancia P (apreptanto, 1mg/kg, IP) e antagonista de receptores NMDA (MK-801, 0,5mg/kg, IP) 30 minutos antes da administraÃÃo de OXL (1mg/kg, IV) por 4 semanas e meia. Paralelamente foram realizados testes nociceptivos para avaliar o desenvolvimento da neuropatia sensitiva perifÃrica. A hipernocicepÃÃo foi avaliada pelo teste de imersÃo da cauda (TIC) em Ãgua fria (10ÂC) ou aquecida (43ÂC) e pelo teste Von Frey (HPM). Em seguida, foi realizado imunofluorescÃncia do segmento medular e gÃnglio da raiz dorsal e RT-PCR. Resultados: Como resultados observou-se que com o prÃ-tratamento ao uso de OXL que houve atenuaÃÃo da hiperalgesia da NSP induzida por OXL. Ao realizar a administraÃÃo de antagonistas seletivos de endotelina-1 intraplantar na pata direita observou-se reduÃÃo significativa na hiperalgesia na pata direita (tratada) em comparaÃÃo à pata esquerda (controle). Ao analisar a expressÃo gÃnica para cFos, NK-1 e o receptor de endotelina B, observou-se que houve reduÃÃo significativa da expressÃo dos marcadores no grupo prÃ-tratado com Bosentana ao comparar com o grupo OXL, que demonstrou a expressÃo aumentada para esses marcadores. ConclusÃo: Conclui-se no presente estudo que hà evidÃncias do papel da endotelina-1, de receptores (TRPV1 e NMDA) e da substÃncia P na patogÃnese da NSP induzida pelo agente antineoplÃsico OXL. / Introduction: The cumulative neurotoxicity is a toxicity that can result from oxaliplatin-based therapy (OXL), which is the 3rd generation platinum agent with broad spectrum of antitumor activity, including colorectal, ovarian and lung cancer. Neurotoxicity associated with OXL generates a dose-limiting toxicity, chronic, peripheral sensory neuropathy (NSP). Objective: To investigate the involvement of endothelin-1, TRPV1 receptors and NMDA and substance P involved in the pathogenesis of peripheral sensory neuropathy induced by oxaliplatin antineoplastic agent. Methods: Male Swiss mice (20g) were pre-treated with antagonists of endothelin-1 receptors (Bosentan 100mg / kg orally; BQ-123 and BQ-788 30μl, intraplantar) and TRPV1 receptor antagonists (capsazepine, 5mg / kg , IP), antagonist of NK-1 receptor for substance P (apreptanto, 1 mg / kg, IP), and a NMDA receptor antagonist (MK-801, 0.5mg / kg, IP) 30 minutes before administration of OXL (1mg / kg, IV) for 4.5 weeks. Parallel nociceptive tests performed to assess the development of peripheral sensory neuropathy. The hyperalgesia assessed by the tail immersion test (ICT) in cold water (10 C) or warm (43 C) and test Von Frey (HPM). Then it was performed spinal segment, and the dorsal root ganglion immunofluorescence and RT-PCR the Ethics Committee approved the study for Animal Research UFC (Protocol 75/12). Results: The results observed when using the antagonists, as a pretreatment to the use of OXL there was attenuation of the induced hyperalgesia (NSP) OXL. Upon administration of selective antagonists of endothelin in the right paw was significant reduction in paw hyperalgesia in the right (treated) compared to the left paw (control). By analyzing the gene expression of cFos, NK-1 and endothelin B receptor, it was observed that there was significant reduction of expression of the markers in pre-treated bosentan group versus OXL group that showed increased expression for these markers. Conclusion: It was concluded in this study that there is evidence of the role of endothelin-1 receptors (TRPV1 and NMDA) and substance SP in the pathogenesis of NSP induced antineoplastic agent OXL.

Introdução: A Neuropatia auditiva/Dessincronia auditiva (NA) é um transtorno que foi identificado há apenas 20 anos, os pacientes que possuíam este transtorno eram diagnosticados como deficientes auditivos como conseqüência da falha no diagnóstico. Com o surgimento do registro das Emissões Otoacústicas e sua presença no repertório de testes de avaliação auditiva, foi possível ao clínico fazer o diagnóstico de NA. Assim sendo, é possível que alguns indivíduos que foram diagnosticados como portadores de uma perda auditiva neurossensorial, tivessem, na verdade, NA. Objetivos: O objetivo deste estudo foi caracterizar o tipo e grau da deficiência auditiva em uma população de deficientes auditivos da cidade de São Paulo; verificar a época da suspeita pelos pais da deficiência auditiva bem como do diagnóstico audiológico nestes indivíduos; identificar os participantes cujas avaliações comportamentais são incompatíveis com as avaliações eletrofisiológicas, visando identificar casos de Neuropatia Auditiva e realizar estudo qualitativo de casos dos participantes com incompatibilidade de respostas nas avaliações comportamentais e eletrofisiológicas. Método: Foram avaliados 89 deficientes auditivos de três escolas especiais da cidade de São Paulo e 11 do setor de Audiologia Educacional da Faculdade de Medicina da Universidade de São Paulo através de alguns testes audiológicos: imitanciometria, audiometria tonal limiar (ATL), emissões otoacústicas (EOA) e potencial evocado auditivo do tronco-encefálico (PEATE). Resultados: Dos 100 participantes deste estudo, 99% apresentaram uma deficiência auditiva do tipo neurossensorial e em 50% o grau predominante da deficiência auditiva foi profundo, um deles não conseguiu realizar a ATL. A média de idade da suspeita dos pais foi de 15,52 meses e o diagnóstico clínico foi de 25,07 meses, em todos os grupos a suspeita dos pais foi anterior ao diagnóstico. Apenas um participante apresentou avaliações comportamentais incompatíveis com as eletrofisiólogicas, todavia, no decorrer da pesquisa o quadro foi modificado, sendo que a flutuação da audição foi o fator mais marcante observado. Conclusões: Os resultados sugerem que a NA é um transtorno raro mesmo na população dos deficientes auditivos e alertam para a necessidade de acompanhar longitudinalmente os casos de suspeita do transtorno / Introduction: Auditory Neuropathy/Auditory Dys-synchrony (AN) is a disorder identified only 20 years ago. Due to diagnosis failure, patients with this disorder were diagnosed as hearing impaired. AN diagnosis was made possible upon the appearance of OAE\'s recordings and its presence in hearing evaluation battery. Therefore, it is possible that some individuals who have been diagnosed as suffering from sensorioneural hearing loss had indeed AN. Purpose: The purpose of this study was to characterize the type and degree of auditory impairment in a population of the hearing impaired in the city of São Paulo; to verify when parents had the suspicious of the hearing impairment and when was the audiological diagnosis done in these individuals; to identify the subjects whose behavioral evaluations are not compatible with the electrophysiological evaluations in order to identify Auditory Neuropathy events and carry out a qualitative study of the cases of subjects with incompatibility of responses in the behavioral and electrophysiological evaluations. Method: 89 hearing impaired individuals from three school for the deaf in the city of São Paulo, and 11 from the Educational Audiology Division of the Medicine School of the University of São Paulo were evaluated in some audiological tests: imitanciometry, audiometer evaluation (AE), otoacoustic emissions (OAE) and Auditory Brainstem Response (ABR). Results: Out of the 100 subjects in this study, 99% presented a sensorioneural hearing loss, and in 50% the predominant degree of auditory loss was profound, one of the subjects was not able to perform AE. The average age of parents suspicion was 15.52 months and the clinical diagnosis was 25.07 months, in all the groups the parents suspicion was prior to the formal diagnosis. Only one subject presented behavioral evaluations incompatible with the electrophysiological, however, in the course of the research the chart was changed, whereas the hearing fluctuation was the most remarkable factor observed. Conclusions: The results suggest that AN is a rare disorder even in the hearing impaired community and alert the need of long term follow up in the cases of suspected disorder

Foi estudada a ação do fator neurotrófico ciliar (CNTF) e da interleucina 6 (IL-6) exógenos na regeneração nervosa periférica. Aplicação de CNTF recombinante humano: o nervo ciático de 12 camundongos adultos C57BL/6J (3 grupos, n=4) foi seccionado e os cotos proximal e distal ancorados com ponto único de sutura no interior de tubo de polietileno (TP) com 6 mm d e comprimento e 0,76 mm de diâmetro interno, com intervalo de 4 mm entre os cotos. Os TP foram implantados vazios ou preenchidos com uma das seguintes soluções: (1) colágeno (col.) purificado (Vitrogen, 2,4 mg/ml) em tampão fosfato (0,2M), na proporção d e 1:1; (2) col.+CNTF (1:1, com 100 ng/ml de CNTF/tubo). Após 6 semanas os tubos contendo ao cabos nervosos regenerado s (CR) foram processados e incluídos em Epon. Fibras nervosas mielínicas foram contadas na porção média dos CR com um sistema controlado por computador (Biographics). Camundongos que receberam CNTF apresentaram número significativamente maior de axônios regenerados (3027±62, média±erro padrão) em relação aos animais implantados com tubos vazios (1384±128) ou preenchidos apenas com colágeno (1639±104). Outros 12 animais adicionais tiveram o nervo ciático seccionado e reparado da mesma maneira. Após 6 semanas, um tubo contendo solução do traçador neuronal HRP foi implantado no coto distal do nervo. Decorrido um período suplementar de 3 dias, neurônios marcados foram contados na medula espinhal e nos gânglios das raízes dorsais L4,5,6- Não houve diferença significante no número de motoneurônios entre os diferentes grupos experimentais (vazio=740±21; col.=749±44; CNTF=790±14) e o s animais não-operados (794±30). Não houve também diferença significante no número de neurônios sensitivos entre os diferentes grupos experimentais (vazio=1920±59; co!.=2262±152; CNTF=2124+96) e todos apresentaram número menor de neurônios sensitivos quando comparados com os animais não operados (4211+96) Aplicação de IL-6 recombinante murina: 12 camundongos C57BL/6J adultos foram divididos em dois grupos (n=6) e implantados com TP preenchidos com: (1) Vitrogen (2,4 mg/ml) e tampão fosfato (0,2 M), na proporção d e 1:1; (2) Vitrogen + IL-6 (1:1, com 100 |ig/ml de IL-6/tubo). Após tempo d e sobrevida de 6 semanas , os tubos com os CR foram processados da mesma forma que no experimento anterior. Fibras nervosas mielínicas foram contadas na porção média d o s CR. Os resultados mostraram que os animais implantados com col.+IL-6 tinham número significativamente maior de axônios mielínicos (2025+143) que os animais injetados apenas com col. (1542±122). O gânglio L5 foi também removido dos mesmos animais e cortado seriadamente (5|am), para posterior contagem do número de neurônios sensitivos. Não houve diferença significante no número de neurônios sensitivos entre os grupos experimentais (col.=528+42, col.+IL-6=554±37); todos, no entanto, apresentaram número significantemente menor de neurônios sensitivos quando comparados com os animais não operados (1112+63). Esses resultados indicam que a aplicação local de CNTF ou IL-6 estimula a regeneração de nervos seccionados e que este efeito é devido, provavelmente, a um aumento da taxa de brotamento dos axônios em regeneração / We studied the actions of exogenous ciliary neurotrophic factor (CNTF) and interleukin-6 (IL-6) on peripheral nerve regeneration. The sciatic nerve of 12 adult C57BL/6J mice (3 groups; n=4) w a s transected and both proximal and distal nerve stumps were secured by a single 10-0 suture into a 6-mm of a polyethylene tube (PT) (0,76 mm ID) to give a final gap length of 4mm. The PT were implanted empty or filled with one of the following solutions: (1) a purified preparation of collagen (Vitrogen, 2,4 mg/ml) plus phosphate buffer solution (0,2M), in 1:1 ratio; (2) Vitrogen + human recombinant CNTF (1:1, with 100 ng/ml of CNTF/tube). After 6 weeks the tubes containing the regenerated nerve cables (NC) were processed for Epon embedding. Myelinated nerve fibers were counted from the mid-portion of the cab les with a computer-controlled system (Biographics). CNTF injected mice regenerated significantly more myelinated axons (3027±62, mean±SEM) compared to the animals implanted with tubes left empty (1384±128) or filled with collagen alone (1639±104). Next, 12 additional animals had the sciatic nerve transected and repaired a s above. After 6 weeks, HRP was applied to the distal stump of the regenerated nerves and labeled neurons were counted in the spinal cord an d L4.5.6 dorsal root ganglia (DRG). No significant difference in the number of motoneurons was detected between the experimental (empty=740±21; collagen=749±44; CNTF=790±14) and non-operated (794±30) animals. No difference was also found in the n umber of labeled DRG neurons among the experimental groups (empty=1920±59; collagen=2262±152; CNTF=2124±96) and all had fewer labeled sensory neurons compared to the non-operated group (4211+96). For the IL-6 experiments, 12 C57BL/6J mice were divided into 2 groups (n=6) and implanted with PT filled with one of the following solutions: (1) Vitrogem (2,4 mg/ml) plus phosphate buffer solution (0,2 M), in 1:1 ratio; (2) Vitrogen + murine recombinant IL-6 (1:1, with 100 |ig/ml of IL-6/tube). Following a survival time of 6 weeks, the tubes with the regenerating nerve cables were processed for Epon embedding and myelinated nerve fiber counting. The results showed a significant difference in the number of myelinated axons between the collagen+IL-6 group (2025±143) and the collagen alone group (1542±122). The L5 DRG was also removed from the same mice, and serially sectioned (5^m) for sensory neuron counts. No significant difference was found in the number of DRG neurons between the experimental groups (collagen=528±42; collagen+IL-6=554±37). However, all had significantly fewer sensory neurons compared to the non-operated group (1112+63). These results indicate that locally applied CNTF and IL-6 stimulate peripheral nerve regeneration in adult animals, and that the effects are due to a neurite-promoting activity on axotomized neurons

Les canaux calciques de type T Cav3.2 sont des régulateurs clés des fonctions sensorielles, et de fait sont également des cibles intéressantes pour le développement de nouveaux composés analgésiques pour le traitement et le management de la douleur. Malgré de récentes avancées dans l’identification de petites molécules organiques ciblant la famille des canaux Cav3.x/Type T, il reste encore à identifier un inhibiteur spécifique de Cav3.2. Le venin d’araignées contient une large diversité de neurotoxines incluant des modificateurs de gating des canaux calciques. En utilisant des canaux calciques recombinants, nous avons procédé à un criblage d’une bibliothèque de venins et avons identifié un nouveau peptide de 28 acides aminés (Psp3Tx1). La forme synthétique de ce peptide a été utilisé pour déterminer son profil de selectivité sur un panel de membres proches de la famille des canaux calciques (Cav) et sodiques (Nav) dépendants du voltage. Le peptide est sélectif pour le canal Nav1.7 (une cible largement validée dans le contexte des pathologies de la douleur) avec un effet complémentaire sur Cav3.2 à de fortes doses. In vivo chez la souris, le peptide possède des propriétés analgésiques avec des effets anti-hyperalgésiques et anti-allodyniques dans un contexte de douleur neuropathique. Ce peptide possède également un pouvoir analgésique dans un contexte de douleur spontanée induit par un agoniste des canaux Nav1.7. Les résultats présentés dans cette thèse sont encourageants pour la mise en place d’un projet amenant Psp3Tx1 au niveau clinique. / The T-type calcium channel Cav3.2 emerges as a key regulator of sensory functions, and therefore is an interesting drug target to develop innovative analgesic compounds for improved chronic pain management. Despite recent advances in the identification of small organic molecules targeting the Cav3.x/T-type calcium channel family, to date specific Cav3.2 inhibitors remains to be identified. Spider venoms proved to contain a large diversity of neurotoxins including gating modifiers of calcium channels. Using recombinant Cav3.2 channels, we performed a screening of a Tarantula venom library and identified a new 28 amino acid peptide (Psp3Tx1). The synthetic form of the peptide was used to determine its selectivity profile over a panel of closely related members of the voltage gated calcium (Cav) and sodium (Nav) channels. The peptide proved to be selective for the Nav1.7 channel (largely validated target in the context of pain pathologies) with an additional effect on Cav3.2 at more elevated doses. In vivo in mice, the peptide demonstrated to be an efficient analgesic molecule with anti hyperalgesic and antiallodynic properties in the context of neuropathic pain. This peptide also possess analgesic properties in a context of spontaneous pain induced by a Nav1.7 agonist. The results presented in this thesis are encouraging for the setup of a project taking Psp3Tx1 into clinical tests.