Gustavo Simoes

Tendon injuries represent a clinical challenge in regenerative medicine because their natural repair process is complex and inefficient. The high incidence of tendon injuries is frequently associated with sports practice, aging, tendinopathies, hypertension, diabetes mellitus, and the use of corticosteroids. The growing interest of scientists in using adipose-derived mesenchymal stem cells (ADMSC) in repair processes seems to be mostly due to their paracrine and immunomodulatory effects in stimulating specific cellular events. ADMSC activity can be influenced by GDF-5, which has been successfully used to drive tenogenic differentiation of ADMSC in vitro. Thus, we hypothesized that the application of ADMSC in isolation or in association with GDF-5 could improve Achilles tendon repair through the regulation of important remodeling genes expression. Lewis rats had tendons distributed in four groups: Transected (T), transected and treated with ADMSC (ASC) or GDF-5 (GDF5), or with both (...

Os biomateriais poli L-ácido lático (PLLA) e o poli caprolactona (PCL) são os polímeros mais estudadas na área dos materiais bioreabsorvíveis. Dentre as suas principais características que contribuem para a interação celular, temos a especificidade química da superfície, elétrica, hidrofobicidade e topografia. Ainda, observa-se o tempo de degradação, porosidade, biocompatibilidade com o tecido biológico, bem como, a confecção com as mais variadas formas e dimensões. Já a prática da cultura celular, tem como objetivo estudar a adesão, migração, diferenciação e a proliferação celular utilizando-se um determinado material ou substância. Contudo, poucos trabalhos utilizando os biomateriais ora supracitados e a aplicação em células neuro2A foram realizados. Sabe-se que este tipo celular é derivado de células embrionárias da crista neural, as quais originam em neurônios simpáticos e apresentam como característica a imortalidade, portanto, são excelentes modelos em ensaios in vitro. Nesse ...

Multiple sclerosis is an autoimmune disease of the CNS (Central Nervous System) with progressive character. The e x p e r i m e n t a l a u t o i m m u n e encephalomyelitis (EAE) model is able to reproduce the pathogenicity of multiple sclerosis-associated immune response. The encephalitogenic T lymphocytes play an important role in multiple sclerosis and have been shown to modulate these cells through therapeutic strategies. Pregabalin is a Gamma-Amino Butyric Acid (GABA) analog drug, with GABA-like activity, that acts as an anticonvulsant which reduces the release of norepinephrine and glutamate, and have the ability to modulate the excitatory synaptic transmission and p r o m o t e a n t i - a p o p t o t i c a n d a n t i -inflammatory effects. OBJECTIVES: M o r p h o l o g i c a l l y a n a l y z e i n v i t r o neuroprotection promoted by pregabalin in neuronal cells cultured with conditioned m e d i u m f r o m e n c e p h a l i t o g e n i c T lymphocytes. METHODS: C57BL/6 ...

The purpose of this study was to investigate the influence of implanting collagen with a supramolecular organization on peripheral nerve regeneration, using the sciatic nerve tubulization technique. For this purpose, adult female Sprague Dawley rats were divided into five groups: (1) TP - sciatic nerve repaired with empty polyethylene tubular prothesis (n = 10), (2) TPCL - nerve repair with empty polycaprolactone (PCL) tubing (n = 8), (3) TPCLF - repair with PCL tubing filled with an implant of collagen with a supramolecular organization (n = 10), (4) AG - animals that received a peripheral nerve autograft (n = 8), and (5) Normal nerves (n = 8). The results were assessed by quantification of the regenerated fibers, nerve morphometry, and transmission electron microscopy, 60 days after surgery. Immunohistochemistry and polarization microscopy were also used to analyze the regenerated nerve structure and cellular elements. The results showed that the AG group presented a larger number...

The optimization of an organic scaffold for specific types of applications and cells is vital to successful tissue engineering. In this study, we investigated the effects of a new fibrin sealant derived from snake venom as a scaffold for mesenchymal stem cells, to demonstrate the ability of cells to affect and detect the biological microenvironment. The characterization of CD34, CD44 and CD90 expression on mesenchymal stem cells was performed by flow cytometry. In vitro growth and cell viability were evaluated by light and electron microscopy. Differentiation into osteogenic, adipogenic and chondrogenic lineages was induced. The fibrin sealant did not affect cell adhesion, proliferation or differentiation and allowed the adherence and growth of mesenchymal stem cells on its surface. Hoechst 33342 and propidium iodide staining demonstrated the viability of mesenchymal stem cells in contact with the fibrin sealant and the ability of the biomaterial to maintain cell survival. The new f...

Cell therapy constitutes a possibility for improving nerve regeneration, increasing the success of nerve repair. We evaluate the use of mononuclear cells in the regeneration of the sciatic nerve after axotomy followed by end-to-end neurorrhaphy. Forty adult male Wistar rats (250-300 g) were divided into four groups: (1) sham, (2) neurorrhaphy: the sciatic nerve was sectioned and repaired using epineural sutures, (3) culture medium: after the suture, received an injection of 10 μL of culture medium into the nerve, and (4) mononuclear cell: after the suture, a concentration of 3 × 10(6) of mononuclear cell was injected in epineurium region. Mononuclear cells were obtained from the bone marrow aspirates and separated by Ficoll-Hypaque method. The histological analyses were performed at the 4th postoperative day. The sciatic functional index, histological, and morphometric analyzes were used to evaluate nerve regeneration at the 6th postoperative week. Six rats were used for immunohistochemical analysis on the 4th postoperative day. In the group 4, on the fourth day, the histological analysis demonstrated a more accelerated degenerative process and an increase of the neurotrophic factors was observed. In the 6th week, all the morphometric results of the group 4 were statistically better compared with groups 2 and 3. There was a statistically significant improvement in the sciatic functional index for group 4 compared with groups 2 and 3. Mononuclear cells stimulated nerve regeneration, most probably by speeding up the Wallerian degeneration process as well as stimulating the synthesis of neurotrophic factors.

Background Astrocytes play a major role in preserving and restoring structural and physiological integrity following injury to the nervous system. After peripheral axotomy, reactive gliosis propagates within adjacent spinal segments, influenced by the local synthesis of nitric oxide (NO). The present work investigated the importance of inducible nitric oxide synthase (iNOS) activity in acute and late glial responses after injury and in major histocompatibility complex class I (MHC I) expression and synaptic plasticity of inputs to lesioned alpha motoneurons. Methods In vivo analyses were carried out using C57BL/6J-iNOS knockout (iNOS-/-) and C57BL/6J mice. Glial response after axotomy, glial MHC I expression, and the effects of axotomy on synaptic contacts were measured using immunohistochemistry and transmission electron microscopy. For this purpose, 2-month-old animals were sacrificed and fixed one or two weeks after unilateral sciatic nerve transection, and spinal cord sections w...