Comparative long-term study between two dermal regeneration templates for the reconstruction of burn scar contractures in humans: Clinical and histological results.

The advent of dermal regeneration templates has fostered major advances in the treatment of acute burns and their sequelae, in the last three decades. Both data on morphological aspects of the newly-formed tissue, and clinical trials comparing different templates, are few. The goal of this study was to prospectively analyze the outcome of randomized patients treated with two of the existing templates, followed by thin skin autograft. They are both 2 mm-thick bovine collagen templates (Matriderm® and Integra®), the latter includes a superficial silicone layer. Surgery was performed on patients with impaired mobility resulting from burn sequelae (n = 12 per template) in a two-step procedure. Negative pressure therapy was applied after surgery; patients were monitored for 12 months. No intra or postoperative complications were observed. Data on scar skin quality (Vancouver scar scale), rate of mobility recovery, and graft contraction were recorded; as well as morphological analyses at light microscopical level. Improvement in mobility and skin quality were demonstrated along with graft contraction, in all patients. The double layer template showed the best performance in retraction rate, skin quality and mobility recovery. The subepidermal newly-formed connective tissue showed no histoarchitectural differences between the templates. The double layer template was not absorbed up to 12 months after placement.

Botulinum toxin type A on cutaneous flap viability in diabetic and tobacco-exposed rats.

PURPOSE: To investigate the effect of Botulinum toxin A (BoNTA) on skin flap viability in healthy, tobacco-exposed and diabetic rats. METHODS: Ninety male Wistar rats (250-300g) were randomly divided into six groups: control+saline (C1), control+BoNTA (C2), tobacco-exposed+saline (T1), tobacco-exposed+BoNTA (T2) diabetes+saline (D1) and diabetes+BoNTA (D2). A dorsal cutaneous flap (3×10cm) was performed. Survival area and total area of the flaps were measured. Lumen diameter, external arterial diameter and lumen/wall thickness ratio were recorded. RESULTS: Survival area increased in control group with BoNTA injection compared with control animals injected with saline (C2 x C1; 0.9±0.1 vs0.67±0.15, p= 0.001). A similar result was found in diabetes group injected with BontA (D2 x D1; 0.97±0.2 vs0.61±0.24, p=0.018). No difference was observed in skin flap viability in tobacco-exposed groups (T2 x T1; 0.74±0.24 vs 0.64±0.21, p=0.871). Lumen diameter (p= 0.004), external arterial diameter (p = 0.0046,) and lumen/wall thickness ratio (p= 0.003) were increased in diabetes+BoNTA-treated animals. This effect was not observed in control or in tobacco-exposed groups. CONCLUSIONS: Botulinum toxin A increased skin flap viability in control and diabetic rats on the seventh post-operative day. Increased lumen diameter, external arterial diameter, and lumen/wall thickness ratio were observed in the diabetes+BoNTA group. BoNTA had no effect in the tobacco-exposed group on the seventh postoperative day.

Botulinum toxin type A on cutaneous flap viability in diabetic and tobacco-exposed rats

PURPOSE:To investigate the effect of Botulinum toxin A (BoNTA) on skin flap viability in healthy, tobacco-exposed and diabetic rats.METHODS: Ninety male Wistar rats (250-300g) were randomly divided into six groups: control+saline (C1), control+BoNTA (C2), tobacco-exposed+saline (T1), tobacco-exposed+BoNTA (T2) diabetes+saline (D1) and diabetes+BoNTA (D2). A dorsal cutaneous flap (3×10cm) was performed. Survival area and total area of the flaps were measured. Lumen diameter, external arterial diameter and lumen/wall thickness ratio were recorded.RESULTS: Survival area increased in control group with BoNTA injection compared with control animals injected with saline (C2 x C1; 0.9±0.1 vs0.67±0.15, p= 0.001). A similar result was found in diabetes group injected with BontA (D2 x D1; 0.97±0.2 vs0.61±0.24, p=0.018). No difference was observed in skin flap viability in tobacco-exposed groups (T2 x T1; 0.74±0.24 vs 0.64±0.21, p=0.871). Lumen diameter (p= 0.004), external arterial diameter (p = 0.0046,) and lumen/wall thickness ratio (p= 0.003) were increased in diabetes+BoNTA-treated animals. This effect was not observed in control or in tobacco-exposed groups.CONCLUSIONS:Botulinum toxin A increased skin flap viability in control and diabetic rats on the seventh post-operative day. Increased lumen diameter, external arterial diameter, and lumen/wall thickness ratio were observed in the diabetes+BoNTA group. BoNTA had no effect in the tobacco-exposed group on the seventh postoperative day.

Tratamento da sequela de queimadura com uso de substituto dérmico aloplástico, avaliação clínica e histológica: estudo piloto / Clinical and histological evaluation of dermal regeneration in burn sequel with use of alloplastic dermal substitute: pilot stud

Introdução: O surgimento dos substitutos de regeneração dérmica nas duas últimas décadas permitiu um grande avanço no tratamento tanto das queimaduras agudas como das sequelas. No entanto, ainda há carência de informações sobre a relação entre os resultados clínicos e o que ocorre no tecido com cada tipo de matriz. Objetivo: Avaliar o aspecto histológico e correlacioná-lo aos resultados clínicos obtidos com o uso de dois tipos de substitutos dérmicos existentes no mercado, um deles mais fino e com uma lâmina de silicone (Integra®) e outro mais espesso e sem essa lâmina de silicone (Matriderm®). Método: Dez pacientes com sequelas de queimaduras foram tratados. Cada 5 pacientes receberam um desses dois tipos de matriz, ambos associados à terapia de pressão negativa. Após 19 dias, foi realizado um autoenxerto fino. Foram colhidas biópsias 12, 60 e 180 dias após o enxerto. Resultados: A análise histológica de ambos os substitutos mostrou o crescimento de tecido conjuntivo bem vascularizado sobre o leito cirúrgico destituído do tecido cicatricial original, com desenvolvimento adequado para recebimento do enxerto. Porém, houve diferenças quanto ao tempo de permanência no tecido, à integridade e à retração das matrizes: o substituto dérmico mais espesso apresentou maior retração tecidual, mas, também, maiores taxas de integração, e deixou de ser observado nos cortes histológicos mais precocemente em relação ao substituto fino com lâmina de silicone. Conclusão: O substituto dérmico de duas camadas (com lâmina de silicone) mostrou-se do ponto de vista clínico com menor retração ao longo de 6 meses, assim como com menor contagem de Vancouver. Do ponto de vista histológico, as diferenças foram apenas quanto à presença de matriz.

Introduction: The appearance of the dermal substitute regeneration over the last two decades has allowed large steps to be taken in the treatment of both acute burns and its sequels. However, there is still lack of information regarding the relationship between the clinical outcomes and what happens in the tissue with each kind of substitute. Objective: To evaluate the histological aspect and correlate it with the clinical results obtained using two kinds of dermal substitute available, one thinner and with a layer of silicone (Integra®) and one thicker and without silicone layers (Matriderm®). Methods: Ten patients with burn sequels were treated: 05 with Integra® and the others with Matriderm®, both associated to the therapy of negative pressure. After 19 days, a thin autograft was performed. After 12, 60 and 180 days from the grafting, biopsies were collected. Results: The histological analysis of both dermal substitutes has shown the growth of vascularized connective tissue where the scarred tissue was settled before, with the right development for receiving the graft. However, there were differences regarding the time it stayed on the tissue, the integrity and retraction of the dermal substitutes: the thicker dermal substitute has presented larger retraction of the tissue but, also, higher rates of integration and could no longer be observed in the histological cuts earlier than the thinner substitute with a silicon layer. Conclusion: Two layers dermal substitute (silicone sheet) proved from the clinical point of view with lower shrinkage over 6 months and less Vancouver count. From the histological point of view, the differences were only for the presence of the matrix.

Estudo comparativo entre pentoxifilina e triancinolona no tratamento das cicatrizes hipertróficas pós-queimadura quanto à remodelação do colágeno e das fibras do sistema elástico / Comparative study of pentoxifylline and triamcinolone in the treatment of post-burn hypertrophic scars on the collagen remodeling and elastic system fibers

Introdução: O tratamento das sequelas cicatriciais permanece um desafio na prática diária. Corticosteroides injetáveis são amplamente utilizados no combate a queloides e cicatrizes hipertróficas, mas substâncias como a pentoxifilina (PTF) também têm demonstrado eficácia clínica na modulação dessas cicatrizes. Objetivos: No presente estudo, propusemos a comparação dos efeitos da PTF e do corticosteroide triancinolona nas cicatrizes hipertróficas de pacientes vítimas de queimaduras por meio de análise histológica da organização das fibras que contêm colágeno e das fibras do sistema elástico. Métodos: Foram estudadas amostras de pele cicatricial de 10 pacientes, entre 20 e 40 anos, com história de queimaduras em tronco, com até 24 meses de evolução, não tratadas cirurgicamente. Cada paciente teve duas áreas cicatriciais tratadas, uma com Hexacetonido de Triancinolona 20 mg/ml e outra com Pentoxifilina 1 mg/ ml; tendo sido realizadas três aplicações intracicatriciais com intervalos mensais. Uma biópsia de cada área tratada foi colhida após 30 dias de cada aplicação. Resultados: Os resultados clínicos foram evidentes e semelhantes para as duas drogas: diminuição da espessura, do prurido, da hiperemia e da consistência da cicatriz. Não se observaram diferenças arquiteturais no tecido conjuntivo subepidérmico quando comparadas a cicatriz original com as cicatrizes após cada tipo de tratamento (grandes feixes de fibras colágenas em todas as direções, com ausência de fibras do sistema elástico). Estudos subsequentes envolvendo a análise da espessura total da cicatriz e o grau de vascularização/ inflamação presentes se fazem necessários na investigação da justificativa da eficácia clínica dos tratamentos. Conclusão: Concluímos que a PTF teve uma resposta clínica e morfológica similar à triancinolona nos casos tratados.

Introduction: The treatment of scarring sequelae remains challenge in daily practice. Injecting corticosteroids are widely used to combat keloids and hypertrophic scars, but substances such as pentoxifylline (PTF) have also demonstrated clinical efficacy in modulating these scars. Objectives: This study set out to compare the effects of TFP and corticosteroid triamcinolone in hypertrophic scars of burn victims by histological analysis of the organization of the fibers containing collagen and elastic system fibers. Methods: Scar skin samples from 10patients were studied between 20 and 40 years, with a history of burns on the trunk, up to 24 months of evolution, not surgically treated. Each patient had two treated scar areas, one with triamcinolone hexacetonide 20 mg/ml and the other with pentoxifylline 1 mg/ml; having been held three intracicatriciais applications at monthly intervals. A biopsy of each treated area was harvested after 30 days of each application. Results: The clinical results were evident and similar for the two drugs: thinning, itching, hyperemia and scar consistency. There were no differences in architectural subepidermal connective tissue when compared with the original scar scars after each treatment (large bundles of collagen fibers in all directions with no elastic system fibers). Subsequent studies involving the analysis of the total thickness of the scar and the extent of vascularization/inflammation gifts are needed to investigate the reasons of clinical efficacy of treatments. Conclusion: We conclude that TFP had a clinical and morphological response similar to triamcinolone in treated cases.

Age-dependent physiological changes in the histoarchitecture of the articular cartilage of the rabbit mandibular condyle: a morphological and morphometric study.

Mandibular condyle articular cartilage participates in condylar postnatal growth and is responsible for adaptations to anatomical and/or biomechanical alterations throughout life. In a preliminary study in rabbits, differences were observed in the thickness of the layers of articular cartilage in control animals at 5 and 6 months (generally considered adults for this purpose). This study aimed to describe sagittally sectioned condylar cartilages stained with Picrosirius-hematoxylin in rabbits at 40 days and 5, 6, 8, 13, and 18 months to determine when histological maturity is reached. At 40 days, 5 layers were seen: fibrous, proliferative, transition, maturation, and hypertrophic. Older animals (5-18 months) lacked the transition layer. Fibrous, proliferative, and hypertrophic regions were considered for morphometric analysis. The thickness of the fibrous region did not change during the analyzed period (p = 0.1899). When proliferative and hypertrophic regions and the total thickness of the cartilage were compared, a difference was detected (p < 0.001). The thickness of the proliferative region was greatest at 40 days and decreased at 5 months; however, it increased at 6 months, when it was significantly thicker than at 5, 8, 13, and 18 months. Both the hypertrophic region and the total thickness were thickest at 40 days, intermediate at 5, 6, and 8 months, and thinnest at 13 and 18 months. In summary, our data suggest a physiological period of increased cartilage growth at 6 months. Additionally, rabbits at this age should be avoided in experiments involving condylar cartilage. Finally, 13-month-old rabbits have reached histological maturity of the condylar cartilage.

Effect of ultrasound therapy on the repair of gastrocnemius muscle injury in rats.

The aim of this study was to evaluate the effect of the pulsed ultrasound therapy (PUT) in stimulating myoregeneration and collagen deposition in an experimental model of lacerative gastrocnemius muscle lesion in 30 Wistar rats. Fifteen rats were treated (TG) daily with 1 MHz pulsed ultrasound (50%) at 0.57 W/cm(2) for 5 min, and 15 were control animals (CG). Muscle samples were analyzed on postoperative days 4, 7 and 14 through H&E, Picrosirius-polarization and immunohistochemistry for desmin. The lesions presented similar inflammatory responses in both treated and control groups. The areal fraction of fibrillar collagen was larger in the TG at 4 days post-operatively (17.53+/-6.2% vs 6.79+/-1.3%, p=0.0491), 7 days (31.07+/-7.45% vs 12.57+/-3.6%, p=0.0021) and 14 days (30.39+/-7.3% vs 19.13+/-3.51%, p=0.0118); the areal fraction of myoblasts and myotubes was larger in the TG at 14 days after surgery (41.66+/-2.97% vs 34.83+/-3.08%, p=0.025). Our data suggest that the PUT increases the differentiation of muscular lineage cells, what would favor tissue regeneration. On the other hand, it is also suggested that there is a larger deposition of collagenous fibers, what could mean worse functional performance. However, the percentage of fibers seems to have stabilized at day 7 in TG and kept increasing in CG. Furthermore, the collagen supramolecular organization achieved by the TG is also significant according to the Sirius red staining results.

Estudo ultra-sonográfico e morfológico do tendäo patelar doador na reconstruçäo intra-articular do ligamento cruzado anterior / Ultrasonographic and morphologic study of the patellar tendon donor in the intra-articular reconstruction of the anterior cruciate ligament

Em 63 pacientes submetidos a reconstruçao intra-articular do ligamento cruzado anterior com enxerto autógeno do tendao patelar, os autores analisam as dimensoes do tendao patelar do joelho operado e do contralateral nao operado por meio de exame ultra-sonográfico. Cinqüenta e um pacientes sao do sexo masculino e doze, do feminino. As idades variaram de 23 a 47 anos, com média de 30,5 anos. O período do pós-operatório em que os exames foram realizados variou de um a 50 meses, com média de 18,8 meses. Oito pacientes foram submetidos a estudo histológico do tendao patelar remanescente através de biópsia da área doadora de enxerto. O momento do pós-operatório em que as biópsias foram realizadas variou de 33 a 56 meses, com média de 40,8 meses. Observou-se, pela ultra-sonografia, que a largura do tendao patelar doador se equivale à do joelho contralateral a partir do 19§ mês do pós-operatório. A espessura dotendao patelar doador na fase precoce do pós-operatório é de 235 por cento da espessura do tendao patelar contralateral; decresce progressivamente mas mantém-se maior que o lado nao operado em todos os períodos pós-operatório estudados no trabalho. As observaçoes morfológicas demonstraram que o tecido cicatricialformado, embora se assemelhe muito ao normal, nao alcança o mesmo grau de organizaçao original tanto à microscopia de luz quanto à microscopia eletrônica. Observou-se que a reestruturaçao completa dos fascículos nunca foi alcançada nos tendoes patelares operados e que sua composiçao tissular encontrava-se alterada.