L’ingénierie tissulaire vise à régénérer des organes ou des tissus lésés. Ainsi, les gels de fibrine sont largement utilisés pour la reconstruction de différents tissus. Cependant, à concentration physiologique, ils ne peuvent pas être manipulés. Pour améliorer leurs propriétés mécaniques, ils peuvent être combinés dans une architecture de Réseaux Interpénétrés de Polymères (RIP) à un réseau de polymère synthétique (PVA ou POE). Ces RIPs peuvent être rendus biodégradables en copolymérisant d’albumine bovine de sérum modifiée par des groupements méthacrylate (BSAm) avec le partenaire synthétique.Selon leurs compositions, ces matériaux peuvent être complètement dégradés ou fragmentés après quelques jours en présence de thermolysine, une enzyme protéolytique. Ces cinétiques de dégradation de ces RIPs ont été étudiées en suivant le relargage des fragments protéiques hors du matériau, d’une part, et la diminution de leurs propriétés viscoélastiques, d’autre part. Leur biocompatibilité a été vérifiée : des fibroblastes cultivés à leur surface présentent une viabilité supérieure à 90% après 5 semaines de culture et leur prolifération est suivie de la synthèse de macromolécules de la Matrice Extracellulaire.Afin de leur ajouter une action bactéricide et d’augmenter encore leur résistance mécanique, des sels d’ammonium ont également été incorporés à certains de ces RIPs. Enfin, la synthèse de tels RIP a été mise au point à partir de plasma sanguin. Les éventuels phénomènes de rejet lors de leur intégration au sein du corps devraient ainsi être limités. De plus, le plasma sanguin contenant un grand nombre de facteurs de croissance et de molécules bioactives, la réparation tissulaire devrait ainsi être améliorée. / Tissue engineering aims to regenerate deficient tissues and organs. Fibrin gels are widely used for the reconstruction of various tissues. However, at physiological concentration, they can’t be handled. To improve their mechanical properties, they can be combined with a synthetic polymeric network (PVA or PEO) in an Interpenetrating Polymer Network (IPN) architecture. These IPN can be made biodegradable by crosslinking the Bovine Serum Albumin modified by methacrylate groups (BSAm) with the synthetic partner.Depending on the composition, these materials can be fully degraded or fragmented after several days of incubation with thermolysin, a proteolytic enzyme. The degradation kinetics of these hydrogels were studied by following the release of proteic fragments from the material and by the loss of viscoelastic properties. The biocompatibility was also verified: fibroblasts cultivated on the surface show a viability of over 90% after 5 weeks of culture and the proliferation is followed by the synthesis of Extracellular Matrix macromolecules.To add a bactericide property, and to increase their mechanical resistance, ammonium salts were incorporated in those IPN. Lastly, the synthesis of these IPN were adapted, starting from whole blood plasma. Rejection phenomena upon implantation should thus be hindered. Moreover, blood plasma contains a wide variety of growth factors and bioactive molecules, which should improve tissue regeneration.

Traumatic injuries resulting in peripheral nerve lesions often require a graft to bridge the gap. Although autologous nerve graft is still the first choice strategy in reconstructions, it has the severe disadvantage of the sacrifice of a functional nerve. Cell transplantation in a bioartificial conduit is an alternative strategy to create a favourable environment for nerve regeneration. Among adult stem cells, adipose-derived stem cells (ASC) are a useful tool in regenerative medicine as they can be induced towards multiple mesodermal and nonmesodermal lineages, being recently differentiated into cells showing Schwann cell-like morphology, glial cell markers and increased neurotrophic potential. The first two chapters of this work describe in vivo applications of Schwann cell-like differentiated ASC (dASC), seeded into biodegradable nerve guides made of fibrin, investigating both brief (2 weeks) and long (4 months) term effects on the regenerating nerves. Comparison was carried out with similarly differentiated bone marrow mesenchymal stem cells (dMSC), Schwann cells (SC)and empty fibrin conduits, as well as with autologous nerve grafts. Regeneration was evaluated in a 1cm gap total axotomy sciatic nerve injury model on rats. Results showed that dASC could improve regeneration distance in a similar manner to other regenerative cells inthe brief term. This effect was maintained and strengthened in the long term, where nerve morphology, spinal motoneurons regeneration, protection from muscle atrophy and electrophysiological performances of regenerated nerves were analysed. dASC positive effects lasted in the long term with functional results comparable to the autologous nerve grafts, which served as controls. The third chapter focuses on the possibility to further improve dASC regenerative performances using fibronectin and laminin, two key extracellular matrix (ECM) molecules involved in nerve regeneration, with the future aim to optimize cell host, directional cues and neurotrophism of tissue engineered conduits. Fibronectin and laminin protected dASC from stress-induced cell death in vitro, significantly increasing cell adhesion and viability. Laminin significantly improved neurotrophic properties of dASC enhancing neurite outgrowth of both primary sensory neurons and NG108-15 neurons co-cultured with dASC, suggesting a further activation of the neurotrophic effect of dASC by ECM molecules. These improved effects were increased when a direct contact was established between the laminin substrate, dASC and neurons, suggesting a primary role of laminin in contact signalling, finally boosting the neurotrophic potential of dASC. Further studies will be needed to clarify the interactions between dASC and the complexniche of peripheral nerve regeneration, including the ECM molecules. However, the neurotrophic potential of dASC expressed in both in vitro and in vivo experiments opens wide perspectives in tissue engineering applications among new methods to enhance peripheral nerve repair.

A terapia celular representa uma abordagem promissora para o tratamento de cardiopatia isquêmica, porém aspectos-chave dessa estratégia permanecem incertos. Neste trabalho avaliamos a eficiência da retenção cardíaca de células da medula óssea marcadas com tecnécio (99m Tc-CMO) transplantadas, de acordo com o tempo após o infarto (1, 2, 3 e 7 dias) e a via de administração dessas células (intravenosa [IV], intraventricular [IC], intracoronariana [ICO] e intramiocárdica [IM]), em ratos submetidos à isquemia-reperfusão cardíaca [I&R]. Após 24 horas, a retenção cardíaca de 99m Tc-CMO foi maior na via IM comparada com a média alcançada pelas demais (6,79% do total injetado vs. 0,53%). O uso de fibrina como veículo para a injeção de células incrementou a retenção em 2.5 vezes (17,12 vs. 6,84%) na via IM. Curiosamente, quando administradas após 7 dias, a retenção de células na via IM alcançou valores próximos dos observados com da matriz de fibrina injetadas 24 h após a I&R (16,55 vs. 17,12%), enquanto que para as demais vias as mudanças foram insignificantes. Nos animais em que as CMO foram administradas por via intramiocárdica 24 horas após a I&R, com ou sem fibrina, observou-se melhora significante do desempenho cardíaco frente ao estresse farmacológico com fenilefrina quando comparados aos controles. Em conjunto, os dados mostram a biodistribuição das células injetadas após a I&R por 4 diferentes vias e 4 intervalos de tempo pós-lesão e indicam que a via IM é a que produz maior retenção cardíaca. O uso do biopolímero de fibrina aumenta a retenção das células e a eficácia deste efeito sobre a função cardíaca e mortalidade dos animais em longo prazo, além de 30 dias pós I&R, merecerá ser investigada no futuro. / Cell therapy represents a promising approach for ischemic cardiac disease, but key aspects of this strategy remain unclear. We examined the effects of timing and route of administration of bone marrow cells (BMCs) after myocardial ischemia/reperfusion injury (I&R). 99mTc-labeled BMCs were injected by 4 different routes: intravenous (IV), left ventricular cavity (LV), left ventricular cavity with temporal aorta occlusion (LV+) and intramyocardial (IM). The injections were performed 1, 2, 3, or 7 days after infarction. Cardiac retention was higher following the IM route compared to the average values obtained by all other routes (6.79% of the total radioactivity injected vs. 0.53%). Use of a fibrin biopolymer as vehicle during IM injection led to a 2.5-fold increase in cardiac cell accumulation (17.12 vs. 6.84%). Interestingly, the retention of cells administered with culture medium at day 7 post-MI by the IM route was similar to that observed when cells were injected 24 h post-IM using fibrin (16.55 vs 17.12%), whereas no significant changes were observed for the other routes. Cell therapy 24 hs post MI by IM injection, with or without fibrin, resulted in comparable improvement in cardiac function under pharmacological stress compared to control animals. Together, we provide evidence for the biodistribution of 99mTc-labeled BMCs injected post MI by 4 different routes and times post-injury, which shows that the IM rout is the most effective for cardiac cell retention. The use of a fibrin biopolymer further increased cardiac cell retention and its potential long term benefits, beyond 30, on reducing mortality and improving cardiac function deserve to be explored in the future.

No description available.

Motivation In the black population of South Africa, cardiovascular disease (CVD) is rapidly increasing due to urbanisation. Stroke is usually accompanied by a prothrombotic haemostatic profile. Changing lifestyle factors that accompany the urbanisation process could have a negative impact on the haemostatic profile of black South Africans. Elevated levels of pro-coagulant factors, von Willebrand factor (vWF), fibrinogen and fibrin D-dimer have been reported in the black population, which could increase the black population’s susceptibility to CVD. However, low levels of plasminogen activator inhibitor-1 (PAI-1) previously reported in the black population could contribute towards a pro-fibrinolytic state, which may counteract the hypercoagulant state. This may have a beneficial effect on the haemostatic profile of the black population. More investigation into the haemostatic profile of black South Africans is therefore needed to determine if an altered haemostatic profile exists in this group, and if so, to what extent these alterations may relate to cardiovascular dysfunction. This study included markers of both the coagulation (vWF, fibrinogen, fibrin D-dimer) and fibrinolytic (PAI-1, fibrin D-dimer and fibrinolytic potential) systems in an attempt to investigate the haemostatic profile of the black population of South Africa, and for comparison purposes that of the white population as well. The relationship of these markers’ with selected markers of cardiovascular function was also examined to determine if they could possibly contribute to an increase in cardiovascular risk, especially in the black population. Aims The aims of this study were to first compare coagulation and fibrinolysis markers in the black and white populations of South Africa. Furthermore, to determine if associations exist between the selected components of the haemostatic system and markers of cardiovascular function, especially in the black population of South Africa, who tends to be at a higher cardiovascular risk due to altered metabolic and haemostatic profiles. Methodology The Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study was a prospective cohort study that consisted of 409 participants at baseline (2008-2009) that were equally distributed according to both ethnicity (200 black; 209 white) and gender (black, 101 men, 99 women; white, 101 men, 108 women). At follow-up (2011/2012) the cohort totalled 359 participants (170 black, 88 men and 82 women; 189 white, 93 men and 96 women). Data from baseline measurements were used for the first two manuscripts (chapters 2 and 3), while followup data was used for the third manuscript (chapter 4). vWF, fibrinogen, PAI-1, fibrin D-dimer, CLT, serum peroxides, glutathione, glutathione peroxidase and reductase activity were determined, and ambulatory blood pressure and the retinal vessel calibres were measured. The groups were stratified by ethnicity as specified by statistical interaction terms. T-tests and chi-square tests were used to compare means and proportions, respectively. Pearson and partial regression analyses were used to determine correlations between the components of the haemostatic system and cardiovascular function markers. This was followed by multiple linear regression analyses to investigate whether independent associations exist between the variables in both ethnic groups. P-values ≤0.050 were deemed significant. Results and conclusion of each manuscript The first manuscript (chapter 2) compares the haemostatic profiles of the black and white population to determine whether ambulatory blood pressure is related to components of the haemostatic system. The black participants displayed a prothrombotic profile with significantly higher vWF, fibrinogen, PAI-1, fibrin D-dimer and a longer CLT than their white counterparts. Furthermore, partial and multiple linear regression analyses showed a positive association of systolic and diastolic blood pressure with fibrin D-dimer in the black population, while a negative association existed between ambulatory blood pressure and CLT in the white population. These associations suggest that fibrin D-dimer may contribute, at least in part, to the high prevalence of hypertension in the black population. The second manuscript (chapter 3) determined associations between markers of the haemostatic and oxidant-antioxidant systems in the black and white populations. In addition to the prothrombotic profile that exists in the black population, this group also had significantly higher serum peroxides (oxidative stress) and lower glutathione peroxidase activity (antioxidant) levels. Multiple linear regression analyses indicated positive associations between fibrinogen and serum peroxides in both populations. In the white population, an additional positive association was found between serum peroxide and CLT. In the black population, vWF and CLT were negatively associated with GPx activity. The results suggest that there are ethnic-specific relationships between the haemostatic and oxidant-antioxidant systems. The third manuscript (chapter 4) investigated the relationships between the retinal vessel calibres and components of the haemostatic system in the black and white population. The investigation focussed specifically on arteriolar diameters in the lower median, since a narrow arteriolar diameter is known to be associated with elevated blood pressure. In both ethnic groups, a narrower arteriolar calibre was accompanied by narrower venular calibres. Independent positive associations were found between the central retinal vein equivalent (CRVE) and fibrinogen in the black population, as well as vWF and CLT in the white population. In addition, independent negative associations were found between the central retinal artery equivalent and CLT in the black population and with vWF in the white population. The results suggest that haemostatic alterations are linked to early vascular changes that may differ between ethnicities. General conclusion Ethnic-specific relationships between the components of the haemostatic system and measures of cardiovascular function are evident. The prothrombotic profile that is observed in the black population, together with the adverse associations of the haemostatic components with blood pressure, a compromised oxidant-antioxidant profile, and retinal vessel calibres may contribute, at least in part, to the high cardiovascular and cerebrovascular risk evident in this population group. / PhD (Physiology), North-West University, Potchefstroom Campus, 2015

Motivation In the black population of South Africa, cardiovascular disease (CVD) is rapidly increasing due to urbanisation. Stroke is usually accompanied by a prothrombotic haemostatic profile. Changing lifestyle factors that accompany the urbanisation process could have a negative impact on the haemostatic profile of black South Africans. Elevated levels of pro-coagulant factors, von Willebrand factor (vWF), fibrinogen and fibrin D-dimer have been reported in the black population, which could increase the black population’s susceptibility to CVD. However, low levels of plasminogen activator inhibitor-1 (PAI-1) previously reported in the black population could contribute towards a pro-fibrinolytic state, which may counteract the hypercoagulant state. This may have a beneficial effect on the haemostatic profile of the black population. More investigation into the haemostatic profile of black South Africans is therefore needed to determine if an altered haemostatic profile exists in this group, and if so, to what extent these alterations may relate to cardiovascular dysfunction. This study included markers of both the coagulation (vWF, fibrinogen, fibrin D-dimer) and fibrinolytic (PAI-1, fibrin D-dimer and fibrinolytic potential) systems in an attempt to investigate the haemostatic profile of the black population of South Africa, and for comparison purposes that of the white population as well. The relationship of these markers’ with selected markers of cardiovascular function was also examined to determine if they could possibly contribute to an increase in cardiovascular risk, especially in the black population. Aims The aims of this study were to first compare coagulation and fibrinolysis markers in the black and white populations of South Africa. Furthermore, to determine if associations exist between the selected components of the haemostatic system and markers of cardiovascular function, especially in the black population of South Africa, who tends to be at a higher cardiovascular risk due to altered metabolic and haemostatic profiles. Methodology The Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study was a prospective cohort study that consisted of 409 participants at baseline (2008-2009) that were equally distributed according to both ethnicity (200 black; 209 white) and gender (black, 101 men, 99 women; white, 101 men, 108 women). At follow-up (2011/2012) the cohort totalled 359 participants (170 black, 88 men and 82 women; 189 white, 93 men and 96 women). Data from baseline measurements were used for the first two manuscripts (chapters 2 and 3), while followup data was used for the third manuscript (chapter 4). vWF, fibrinogen, PAI-1, fibrin D-dimer, CLT, serum peroxides, glutathione, glutathione peroxidase and reductase activity were determined, and ambulatory blood pressure and the retinal vessel calibres were measured. The groups were stratified by ethnicity as specified by statistical interaction terms. T-tests and chi-square tests were used to compare means and proportions, respectively. Pearson and partial regression analyses were used to determine correlations between the components of the haemostatic system and cardiovascular function markers. This was followed by multiple linear regression analyses to investigate whether independent associations exist between the variables in both ethnic groups. P-values ≤0.050 were deemed significant. Results and conclusion of each manuscript The first manuscript (chapter 2) compares the haemostatic profiles of the black and white population to determine whether ambulatory blood pressure is related to components of the haemostatic system. The black participants displayed a prothrombotic profile with significantly higher vWF, fibrinogen, PAI-1, fibrin D-dimer and a longer CLT than their white counterparts. Furthermore, partial and multiple linear regression analyses showed a positive association of systolic and diastolic blood pressure with fibrin D-dimer in the black population, while a negative association existed between ambulatory blood pressure and CLT in the white population. These associations suggest that fibrin D-dimer may contribute, at least in part, to the high prevalence of hypertension in the black population. The second manuscript (chapter 3) determined associations between markers of the haemostatic and oxidant-antioxidant systems in the black and white populations. In addition to the prothrombotic profile that exists in the black population, this group also had significantly higher serum peroxides (oxidative stress) and lower glutathione peroxidase activity (antioxidant) levels. Multiple linear regression analyses indicated positive associations between fibrinogen and serum peroxides in both populations. In the white population, an additional positive association was found between serum peroxide and CLT. In the black population, vWF and CLT were negatively associated with GPx activity. The results suggest that there are ethnic-specific relationships between the haemostatic and oxidant-antioxidant systems. The third manuscript (chapter 4) investigated the relationships between the retinal vessel calibres and components of the haemostatic system in the black and white population. The investigation focussed specifically on arteriolar diameters in the lower median, since a narrow arteriolar diameter is known to be associated with elevated blood pressure. In both ethnic groups, a narrower arteriolar calibre was accompanied by narrower venular calibres. Independent positive associations were found between the central retinal vein equivalent (CRVE) and fibrinogen in the black population, as well as vWF and CLT in the white population. In addition, independent negative associations were found between the central retinal artery equivalent and CLT in the black population and with vWF in the white population. The results suggest that haemostatic alterations are linked to early vascular changes that may differ between ethnicities. General conclusion Ethnic-specific relationships between the components of the haemostatic system and measures of cardiovascular function are evident. The prothrombotic profile that is observed in the black population, together with the adverse associations of the haemostatic components with blood pressure, a compromised oxidant-antioxidant profile, and retinal vessel calibres may contribute, at least in part, to the high cardiovascular and cerebrovascular risk evident in this population group. / PhD (Physiology), North-West University, Potchefstroom Campus, 2015

A range of microgels with two different functionalities were synthesized, and their utility in novel bioapplications was examined. Cationic microgels with varying properties were developed by tuning synthesis conditions. Their size and primary amine content was analyzed, and one microgel system was selected as a model construct. Its primary amine groups were conjugated to two dyes with properties favorable for utilization as contrast agents in photoacoustic imaging. The concentration of contrast agent in single particles was determined. The implications of a high local dye concentration in the generation of high intensity photoacoustic signals, are discussed. The second bioapplication involved the targeted delivery of fibrinolytics to fibrin clots, in order to bring about dissolution of abnormal thrombi. For this purpose, core/shell microgels with carboxylic acid groups in their shells were synthesized in three size ranges. Following this, their dimension based differential localization in and around porous fibrin clots was examined. Fibrin-specific peptides were then conjugated onto the shells of these particles and the conjugates were shown to demonstrate strong interactions with the fibrin clots. The microgels conjugated to the peptide with the highest binding affinity to fibrin, were observed to bring about disruption of fibrin clots, merely through interference in the dynamic interactions among clot fibers, due to the equilibrium nature of the fibrin polymer. The implications of these novel results and future studies required to facilitate a better understanding of the phenomena involved, are discussed.

Em procedimentos de regeneração óssea guiada (ROG) as membranas de colágeno são os materiais mais utilizados como barreira; porém, sua tendência ao colapso faz indispensável a utilização de materiais de suporte. Para este propósito, os xenoenxertos são substitutos ósseos considerados padrão-ouro, embora apresentem um período longo de reabsorção que impede grande formação do osso. Em contrapartida o ?-fosfato tricálcico (?-TCP) permite boa formação do osso, mas é reabsorvido rapidamente e fracassa quando precisa dar suporte à membrana. O alendronato, um bisfosfonato nitrogenado, é uma droga antirreabsortiva para o tratamento da osteoporose e outras doenças ósseas porque inibe a função dos osteoclastos. O plasma rico em fibrina (PRF) é um concentrado de fibrina sem adição de químicos que consegue estimular processos de cicatrização pelos fatores que fazem parte de sua composição. Neste estudo qualitativo de ROG em defeitos de 5 mm no osso parietal de ratos foi avaliado: 1) o efeito na formação óssea da administração local de 1g/ml de alendronato sódico adicionado a xenoenxerto porcino e a ?-TCP; 2) a adição local de alendronato e PRF a ?-TCP na possibilidade de diminuir a rápida reabsorção do material e impedir o colapso da membrana. Foram usados 100 ratos adultos Wistar distribuídos em 5 grupos (n=20): Xenoenxerto controle (XE-C); xenoenxerto adicionado com alendronato (XE-AL); ?-TCP controle (TCP-C); ?-TCP adicionado com alendronato (TCP-AL); e, ?-TCP adicionado com PRF (TCP-F). Em todos os grupos o enxerto foi coberto com membrana. Dois tempos de estudo de quatro e oito semanas foram considerados para cada grupo (n=10). Ao final de cada tempo, os animais foram sacrificados e as amostras foram fixadas, descalcificadas e processadas para seu estudo em microscopia de luz por meio de análise histológica, histoquímica TRAP e imuno-histoquímica para osteopontina (OPN). Os resultados mostraram maior formação do osso tanto para xenoenxerto como para ?-TCP quando foram adicionados com alendronato local, em ambos tempos de estudo. Nos grupos do ?-TCP a adição de alendronato local permitiu diminuir a reabsorção dos grânulos, melhorando o suporte à membrana ao final dos tempos de estudo; no entanto, no grupo do PRF a reabsorção foi maior e teve pouca formação de osso, provocando colapso da membrana. Adicionalmente, regiões de osso primário subjacentes à membrana de colágeno foram observadas em todos os grupos. / Collagen membranes are the most used materials as a barrier in guided bone regeneration (GBR) procedures; however, its tendency to collapse makes indispensable the use of support materials. For this purpose, xenografts, which are bone substitutes, although they have a long period of resorption that prevents large bone formation, are still considered the gold standard support material. In contrast, tricalcium ?-phosphate (?-TCP) allows good bone formation, but is rapidly reabsorbed and fails when it needs to support the membrane. Alendronate, a nitrogenated bisphosphonate, is an anti-resorptive drug for treatment of osteoporosis and other bone diseases because it inhibits the function of osteoclasts. Fibrin-rich plasma (FRP) is a fibrin concentrate with no added chemicals that can stimulate healing processes by the factors that are part of its composition. In this qualitative study of ROG in 5 mm defects in the rat parietal bone, was evaluated: 1) the effect on bone formation of local administration of 1g / ml sodium alendronate added to porcine xenograft and ?-TCP; 2) the local addition of alendronate and PRF to ?-TCP in the possibility of diminishing the rapid reabsorption of the material and preventing the collapse of the membrane. A 100 adult Wistar rats distributed in 5 groups was used (n = 20): Xenograft control (XE-C); xenograft added with alendronate (XE-AL); ?-TCP control (TCP-C); ?-TCP added with alendronate (TCP-AL); and, ?-TCP added with PRF (TCP-F). In all groups the graft was covered with membrane. Two study times of four and eight weeks were considered for each group (n = 10). At the end of each time, the animals were sacrificed and the samples were fixed, decalcified and processed for light microscopy by histological analysis, TRAP histochemistry and immunohistochemistry for osteopontin (OPN). Results showed higher bone formation for both xenograft and ?-TCP when added with local alendronate at both study times. In the ?-TCP groups the addition of local alendronate allowed to decrease grain resorption, improving membrane support at the end of the study times; however, in the PRF group the resorption was greater and had little bone formation, causing membrane collapse. In addition, primary bone formed in the underlying collagen membrane were observed in all groups.

INTRODUÇÃO: A microanastomose vascular é um componente importante na cirurgia de transferência livre de tecidos. Atualmente, a técnica de sutura convencional ainda é considerada o padrão ouro, no entanto, ela apresenta alguns inconvenientes por ser tecnicamente difícil, consumir muito tempo e ter uma longa curva de aprendizado. Na busca de uma técnica mais fácil e rápida, métodos alternativos de anastomose são estudados incluindo a cola de fibrina. Apesar dos bons resultados publicados, a sua aceitação na prática clínica ainda é limitada. Controvérsias a cerca de sua trombogenicidade e resistência mecânica geram dúvidas em relação a sua segurança. A ausência de um modelo experimental mais fidedigno impede que os potenciais benefícios de sua aplicação clínica sejam apreciados. O objetivo deste estudo é esclarecer essas controvérsias e estudar os benefícios da aplicação da cola de fibrina em um ambiente que simule a prática clínica. MÉTODOS: O modelo experimental utilizado foi a transferência livre de um retalho inguinal para a região cervical anterior. A circulação do retalho era restaurada através de microanastomoses vasculares entre as artérias femoral e carótida (término-lateral) e entre as veias femoral e jugular externa (término-terminal). Utilizamos 20 coelhos que foram divididos em dois grupos (n= 10) de acordo com a técnica de sutura empregada: Grupo I (sutura convencional) e Grupo II (sutura com cola). RESULTADOS: A aplicação da cola de fibrina reduziu significativamente o número de pontos necessários para se completar as anastomoses, 4 pontos a menos nas artérias e 4,5 pontos a menos nas veias. No Grupo I, a média do tempo de anastomose arterial foi de 17,21 minutos, contra 12,72 minutos no Grupo II. Nas anastomoses venosas, a média de tempo no Grupo I foi de 22,93 minutos, contra 16,57 minutos no Grupo II. A aplicação da cola de fibrina também diminuiu o tempo de isquemia do retalho e o tempo de cirurgia em 11,5 minutos e 15,67 minutos, respectivamente. A taxa de sobrevida do retalho foi de 90% nos dois grupos. CONCLUSÕES: A aplicação da cola de fibrina em microanastomoses vasculares demonstrou ser confiável e eficiente no presente estudo. / INTRODUCTION: Microvascular anastomosis is an important component of the free flap surgical procedure. Currently, the conventional suture is still considered the gold standard technique. However, it presents some problems for being technically demanding, time consuming and with a long learning curve. In looking for an easier and faster technique, alternative methods of anastomosis were studied including the fibrin glue. Despite the good results reported in the literature, its acceptance in the clinical setting is still small Controversies regarding its thrombogenicity and mechanical resistance create some concerns about its safeness. The absence of a more realistic experimental model has not allow a full aprecciation of its potencial benefits in clinical use. The aim of this study is clarify these controversies and demonstrate the advantages of fibrin glue application in an environment that can reproduce the clinical practice. METHODS: A free inguinal flap transfer to the anterior cervical region was used as experimental model. The circulation of the flap was restored by means of microvascular anastomosis between the femoral and carotid arteries (end-to-side) and between the femoral and jugular veins (end-to end). The procedures were performed in 20 rabbits that were divided into two groups (n= 10) according to the anastomosis technique: Group I (conventional) and Group II (fibrin glue). RESULTS: The application of fibrin glue significantly reduced the amount of sutures required to complete the anastomoses: 4 less sutures in the arteries and 4,5 less sutures in the veins. In Group I, the mean arterial anastomosis time was 17,21 minutes against 12,72 minutes in Group II. In the veins, the mean anastomosis time in Group I was 22,93 minutes against 16,57 minutes in Group II. The application of fibrin glue also reduced the flap ischemic time and the total operative time by 11,5 minutes and 15,67 minutes, respectively. The flaps\' survival rate was 90% in both groups. CONCLUSIONS: The application of fibrin glue in microvascular anastomoses was reliable and effective in this study.

A incompetência glótica ainda representa um desafio para a laringologia. Implantes de biomateriais no espaço de Reinke ou no espaço paraglótico estão entre as opções de tratamento, e suturas e confecção de bolsões subepiteliais são normalmente utilizados para fixação desses implantes. Alternativamente, a cola biológica pode ser usada como adesivo nesses casos. A cola de fibrina (CF) é produto da reação de dois componentes do sistema de coagulação: o fibrinogênio e a trombina, que formam uma rede de fibrina, responsável, entre outros, pela adesão dos tecidos. Entretanto, além do efeito adesivo, a CF e seus componentes podem interferir no processo cicatricial, atuando sobre citocinas como o fator de crescimento transformador-beta (TGF-beta). O objetivo deste estudo é avaliar o efeito da cola de fibrina na deposição de colágeno após enxertia de fáscia em pregas vocais de coelhos. Dezoito coelhos foram submetidos a enxerto de fáscia em ambas as pregas vocais, sendo o lado esquerdo fixado com CF. Os coelhos foram sacrificados após 7, 30 e 90 dias. As laringes foram removidas e as pregas vocais preparadas para estudo histomorfométrico através da coloração picrossirius, a fim de avaliar a deposição de colágeno total em torno do enxerto. Foi observado um aumento estatisticamente significativo na densidade de colágeno em torno dos enxertos de fáscia nas pregas vocais que receberam a CF (p=0,0102) após 90 dias, em comparação com as pregas vocais controles. A aplicação da CF interferiu na deposição de colágeno em torno dos enxertos de fáscia, resultando em um aumento significativo na densidade de colágeno após 90 dias, possivelmente em decorrência da interação de seus componentes com citocinas e células envolvidas no processo de cicatrização / The glottal incompetence is still a challenge in Laryngology. Implants of biomaterials in Reinkes space or paraglottic space are among the treatment options, and sutures and pockets dissections are usually used to set these implants. Alternatively, biological glue can be used as adhesive in these cases. Fibrin glue (FG) is the product reaction of two components of the coagulation system: the fibrinogen and thrombin that form a fibrin net, responsible for the tissues adhesion, among other functions. However, the FG and its components may interfere in wound healing, interacting with cytokines as the transforming growth factor-beta (TGF-beta). The objective is to study the effect of fibrin glue on collagen deposition after fascia grafting on the rabbits vocal folds. Eighteen rabbits were submitted to the fascia graft on both vocal folds, being the left side fixed with FG. The rabbits were sacrificed after 7, 30 and 90 days. The larynx were removed and vocal folds prepared for histomorphometric study through Picrosirius Red stain, in order to evaluate the collagen deposition around the graft. There was a significant increase in collagen density around the grafts on the vocal folds that received FG (p=0.0102) after 90 days, compared with the control. FG application interfered in collagen deposition around fascia grafts, resulting in a significantly increase of collagen density after 90 days, which possibly resulted from the interaction of FG and its components with the cytokines and cells involved in the wound healing