Alessandra Deise Sebben

End-to-end versus end-to-side motor and sensory neurorrhaphy in the repair of the acute muscle denervation.

Background:The aim of this study was to experimentally compare end-to-end and end-to-side neurorrhaphy in perineural window model after motor nerve lesion, evaluating which one was the most effective to preserve nerves. Also, differences in motor and sensorial nerve regeneration were tested to verify differences in nerve regeneration. Methods:A total of 20 adult male Wistar rats were randomly assigned to 5 groups, and, in each one, a different treatment was performed: besides the control group, and end-to-end or end-to-side graft with motor or sensorial nerves was performed. Silastic sheet was used as a mechanical barrier to prevent innervation from adjacent nerves. After 16 weeks, the specimens were histologically assessed and wet weight was evaluated as a direct parameter of atrophy. Results:The end-to-end neurorrhaphy group presented the best results in terms of mass preservation, but it did not differ significantly from the control group. Motor nerves presented similar results in muscular atrophy. The end-to-side neurorrhaphy group with sensory nerve as donor showed the worst results. Conclusions:The use of sensory nerves to preserve skeletal muscle trophism is not justified, since, according to our model, it affects 50% to 80% of the muscle mass in a period of 16 weeks. End-to-side neurorrhaphy was demonstrated to be an option for re-enervation of a nerve-deprived motor muscle in selected cases.

Regeneração de nervos periféricos: terapia celular e fatores neurotróficos

Traumatismos em nervos perifericos resultam na perda de funcao do orgao inervado e raramente apresentam recuperacao sem a intervencao cirurgica. Diversas tecnicas cirurgicas sao passiveis de serem empregadas para o reparo nervoso. Dentre elas, ressalta-se o uso da tecnica de tubulizacao, podendo ser acrescentados fatores com capacidade regenerativa na câmara. A terapia celular e engenharia de tecidos surgem como uma alternativa para estimular e auxiliar a regeneracao de nervos perifericos. Portanto, o objetivo desta revisao e fornecer um levantamento e uma analise de estudos experimentais e clinicos, quanto aos resultados obtidos, que utilizam a terapia celular e engenharia de tecidos como ferramentas para otimizar o processo de regeneracao. Os artigos utilizados sao oriundos de bases de dados cientificas LILACS e Medline, atraves de pesquisas realizadas no PubMed e SciELO. Artigos sobre o uso de celulas-tronco, celulas de Schwann, fatores de crescimento, colageno, laminina e plasma rico em plaquetas no reparo de nervos perifericos foram sintetizados ao longo da revisao. Com base nos diversos estudos pode-se concluir que a utilizacao de celulas-tronco derivadas de diferentes fontes apresentam resultados promissores na regeneracao nervosa, pois estas possuem capacidade de diferenciacao neuronal, demonstrando, assim, resultados funcionais eficazes. O uso de tubos acrescidos de elementos bioativos com liberacao controlada tambem otimiza o reparo nervoso, promovendo uma maior mielinizacao e crescimento axonal dos nervos perifericos. Outro tratamento promissor e o uso de plasma rico em plaquetas, que, alem de liberar fatores de crescimento importantes no reparo nervoso, ainda serve como um carreador para fatores exogenos estimulando a proliferacao de celulas especificas no reparo de nervo periferico.

PERIPHERAL NERVE REGENERATION: CELL THERAPY AND NEUROTROPHIC FACTORS

Peripheral nerve trauma results in functional loss in the innervated organ, and recovery without surgical intervention is rare. Many surgical techniques can be used for nerve repair. Among these, the tubulization technique can be highlighted: this allows regenerative factors to be introduced into the chamber. Cell therapy and tissue engineering have arisen as an alternative for stimulating and aiding peripheral nerve regeneration. Therefore, the aim of this review was to provide a survey and analysis on the results from experimental and clinical studies that used cell therapy and tissue engineering as tools for optimizing the regeneration process. The articles used came from the LILACS, Medline and SciELO scientific databases. Articles on the use of stem cells, Schwann cells, growth factors, collagen, laminin and platelet-rich plasma for peripheral nerve repair were summarized over the course of the review. Based on these studies, it could be concluded that the use of stem cells derived from different sources presents promising results relating to nerve regeneration, because these cells have a capacity for neuronal differentiation, thus demonstrating effective functional results. The use of tubes containing bioactive elements with controlled release also optimizes the nerve repair, thus promoting greater myelination and axonal growth of peripheral nerves. Another promising treatment is the use of platelet-rich plasma, which not only releases growth factors that are important in nerve repair, but also serves as a carrier for exogenous factors, thereby stimulating the proliferation of specific cells for peripheral nerve repair.

COMPARATIVE STUDY ON USE OF PLATELET-RICH PLASMA ALONE AND IN COMBINATION WITH ALPHA-TRICALCIUM PHOSPHATE CEMENT FOR BONE REPAIR IN RATS

Objectives: To evaluate the effect of alpha-tricalcium phosphate (α-TCP) cement combined with platelet-rich plasma (PRP) on osteogenesis, and to compare the results with use of PRP alone. Methods: A bilateral defect was produced in rat femurs and was filled with one of two types of treatments (PRP or α-TCP + PRP). The outcomes were evaluated after four and eight weeks. Radiographic images provided values for the lesion area, and histology (picrosirius staining) indicated the area of new bone formation. Results: The means relating to the lesion area of the α-TCP + PRP group (2.64 ± 2.07 and 1.91 ± 0.93 mm2, after four and eight weeks, respectively) showed numerically better but non-significant results (p > 0.05) than those seen in the PRP group (5.59 mm 2 ± 2.69 and 3.23 ± 1.46 mm 2, after four and eight weeks, respectively). The mean new bone formation rates were 62.7% ± 12.1 and 79.01% ± 6.25 in the PRP group, and 73.3% ± 12.7 and 85.86% ± 10.45 in α-TCP + PRP group, after four and eight weeks, respectively (p > 0.05). Conclusion: The data from this study suggest that treatment with α-TCP cement combined with PRP does not show any significant difference in comparison with PRP alone. However, there is a possible early effect on bone regeneration when the two biomaterials are applied together.

Estudo comparativo do uso isolado de plasma rico em plaquetas e combinado com cimento de alfa-fosfato tricálcico no reparo ósseo em ratos

OBJECTIVES: To evaluate the effect of alpha-tricalcium phosphate (α-TCP) cement combined with platelet-rich plasma (PRP) on osteogenesis, and to compare the results with use of PRP alone. METHODS: A bilateral defect was produced in rat femurs and was filled with one of two types of treatments (PRP or α-TCP + PRP). The outcomes were evaluated after four and eight weeks. Radiographic images provided values for the lesion area, and histology (picrosirius staining) indicated the area of ​​new bone formation. RESULTS: The means relating to the lesion area of the α-TCP + PRP group (2.64 ± 2.07 and 1.91 ± 0.93 mm², after four and eight weeks, respectively) showed numerically better but non-significant results (p > 0.05) than those seen in the PRP group (5.59 mm ² ± 2.69 and 3.23 ± 1.46 mm ², after four and eight weeks, respectively). The mean new bone formation rates were 62.7% ± 12.1 and 79.01% ± 6.25 in the PRP group, and 73.3% ± 12.7 and 85.86% ± 10.45 in α-TCP + PRP group, after four and eight weeks, respectively (p > 0.05). CONCLUSION: The data from this study suggest that treatment with α-TCP cement combined with PRP does not show any significant difference in comparison with PRP alone. However, there is a possible early effect on bone regeneration when the two biomaterials are applied together.

Minimal Detectable Amounts of Exogenous DNA after Systemic Cell Engraftment

In cellular therapy models, the establishment of accurate methods to track the homing, cell fate and survival are fundamental to ensure safety and efficacy. The PCR is used to detect donor cells DNA in xenotransplant models. Five different concentrations of EGFP+ DNA from C57/BL6 mouse muscle tissue: 1,000 pg/μL, 500 pg/μL, 100 pg/μL, 10 pg/μL e 1 pg/μL were used to contaminate 10 ng/μL of DNA Wistar rat. Polymerase chain reaction was performed using 2 μL of each sample. EGFP+DNA were detected in samples containing 2,000 pg, 1,000 pg, 200 pg and 20 pg. Samples with 2 pg EGFP+DNA did not show signal. Here we demonstrate an alternative to proving the presence or confirm the absence, of exogenous DNA in organs and tissues. The concentration curve for cell migration detection by real time PCR will allow the use in systemically transplanted cells in animal models subjected to cell therapy.

Viability of vascularized bone graft from the iliac crest using the iliac branch of the iliolumbar artery: experimental study on rats

Objective: Through an experimental model, our aim was to create inferences about the viability of vascularized bone grafts from the iliac crest in rats and investigate their histological features. Methods: Twenty-one rats were used, divided into two groups: the first consisted of animals that were subjected to the technique of vascularized bone graft pedicled onto the iliac branch of the iliolumbar artery; the second (control group) underwent the same procedure as performed on the first group, with the addition of ligation of the vascular pedicle. The viability of the bone grafts was observed for three weeks, by means of direct observation of the graft, histology and immunohistochemistry. Results: All the vascularized grafts evaluated in the first week showed viability according to direct observation, histology and immunohistochemistry. However, in the second and third weeks, direct observation showed that 75% of the grafts were unviable, while histological analysis and immunohistochemistry showed that 50% were unviable. Conclusions: Some grafts that are designed to be vascularized became unviable and began to behave like non-vascularized grafts under direct observation and histology. Despite the possibility of failure, use of vascularized bone grafts should be encouraged, because descriptive histology shows greater cell density in the medullary bone portion, and osteocytes that function better regarding deposition of bone matrix, with preservation of the intraosseous vascular network.

Viabilidade do enxerto ósseo da crista ilíaca vascularizado pelo ramo ilíaco da artéria iliolombar: estudo experimental em ratos

OBJECTIVE: Through an experimental model, our aim was to create inferences about the viability of vascularized bone grafts from the iliac crest in rats and investigate their histological features. METHODS: Twenty-one rats were used, divided into two groups: the first consisted of animals that were subjected to the technique of vascularized bone graft pedicled onto the iliac branch of the iliolumbar artery; the second (control group) underwent the same procedure as performed on the first group, with the addition of ligation of the vascular pedicle. The viability of the bone grafts was observed for three weeks, by means of direct observation of the graft, histology and immunohistochemistry. RESULTS: All the vascularized grafts evaluated in the first week showed viability according to direct observation, histology and immunohistochemistry. However, in the second and third weeks, direct observation showed that 75% of the grafts were unviable, while histological analysis and immunohistochemistry showed that 50% were unviable. CONCLUSIONS: Some grafts that are designed to be vascularized became unviable and began to behave like nonvascularized grafts under direct observation and histology. Despite the possibility of failure, use of vascularized bone grafts should be encouraged, because descriptive histology shows greater cell density in the medullary bone portion, and osteocytes that function better regarding deposition of bone matrix, with preservation of the intraosseous vascular network.