Papers by Ana Maria Blanco Martinez
Developmental & Comparative Immunology, 2021
In the present work we have focused on the Histone Deacetylase (HDAC) control of myeloid cells be... more In the present work we have focused on the Histone Deacetylase (HDAC) control of myeloid cells behavior during Xenopus tail regeneration. Here we show that myeloid differentiation is crucial to modulate the regenerative ability of Xenopus tadpoles in a HDAC activity-dependent fashion. HDAC activity inhibition during the first wave of myeloid differentiation disrupted myeloid cells dynamics in the regenerative bud as well the mRNA expression pattern of myeloid markers, such as LURP, MPOX, Spib and mmp7. We also functionally bridge the spatial and temporal dynamics of lipid droplets, the main platform of lipid mediators synthesis in myeloid cells during the inflammatory response, and the regenerative ability of Xenopus tadpoles. In addition, we showed that 15-LOX activity is necessary during tail regeneration. Taken together our results support a role for the epigenetic control of myeloid behavior during tissue and organ regeneration, which may positively impact translational approaches for regenerative medicine.
Neural plasticity, 2018
The regenerative capacity of CNS tracts has ever been a great hurdle to regenerative medicine. Al... more The regenerative capacity of CNS tracts has ever been a great hurdle to regenerative medicine. Although recent studies have described strategies to stimulate retinal ganglion cells (RGCs) to regenerate axons through the optic nerve, it still remains to be elucidated how these therapies modulate the inhibitory environment of CNS. Thus, the present work investigated the environmental content of the repulsive axon guidance cues, such as Sema3D and its receptors, myelin debris, and astrogliosis, within the regenerating optic nerve of mice submitted to intraocular inflammation + cAMP combined to conditional deletion of PTEN in RGC after optic nerve crush. We show here that treatment was able to promote axonal regeneration through the optic nerve and reach visual targets at twelve weeks after injury. The Regenerating group presented reduced MBP levels, increased microglia/macrophage number, and reduced astrocyte reactivity and CSPG content following optic nerve injury. In addition, Sema3D...
Brain research, Jan 14, 2018
Diabetic retinopathy is the leading cause of acquired blindness in working-age individuals. Recen... more Diabetic retinopathy is the leading cause of acquired blindness in working-age individuals. Recent work has revealed that neurodegeneration occurs earlier than vascular insult and that distal optic nerve damage precedes retinal degeneration and vascular insult. Since we have shown that optic nerve degeneration is reduced after optic nerve crush in Galectin-3 knockout (Gal-3 -/-) mice, we decided to investigate whether Gal-3 -/- could relieve inflammation and preserve both neurons and the structure of the retina and optic nerve following 8 weeks of diabetes. Diabetes was induced in 2-month-old male C57/bl6 WT or Gal-3 -/- mice by a single injection of streptozotocin (160 mg/kg). Histomorphometric retinal analyses showed no gross difference, except for a reduced number of retinal ganglion cells in WT diabetic mice, correlated to increased apoptosis. In the optic nerve, Gal-3 -/- mice showed reduced neuroinflammation, suggested by the smaller number of Iba1+ cells, particularly the amo...
Brain research, Jan 26, 2017
Preventing damage caused by nerve degeneration is a great challenge. There is a growing body of e... more Preventing damage caused by nerve degeneration is a great challenge. There is a growing body of evidence implicating extracellular nucleotides and their P2 receptors in many pathophysiological mechanisms. In this work we aimed to investigate the effects of the administration of Brilliant Blue G (BBG) and Pyridoxalphosphate-6-azophenyl-2', 4'- disulphonic acid (PPADS), P2X7 and P2 non-selective receptor antagonists, respectively, on sciatic nerve regeneration. Four groups of mice that underwent nerve crush lesion were used: two control groups treated with vehicle (saline), a group treated with BBG and a group treated with PPADS during 28 days. Gastrocnemius muscle weight was evaluated. For functional evaluation we used the Sciatic Functional Index (SFI) and the horizontal ladder walking test. Nerves, dorsal root ganglia and spinal cords were processed for light and electron microscopy. Antinoceptive effects of BBG and PPADS were evaluated through von Frey E, and the levels of...
Histology and histopathology, Jan 3, 2016
A trauma to the mature central nervous system (CNS) often leads to persistent deficits, due to th... more A trauma to the mature central nervous system (CNS) often leads to persistent deficits, due to the inability of axons to regenerate after being injured. Increasing evidence suggests that pro-inflammatory and pro-apoptotic genes can present a major obstacle to promoting neuroprotection of retinal ganglion cells and consequently succeed in axonal regeneration. This study evaluated the effect of the absence of galectin-3 (Gal-3) on retinal ganglion cells (RGC) survival and axonal regeneration / degeneration after optic nerve crush injury. Two weeks after crush there was a 2.6 fold increase in the rate of cell survival in Gal-3-/- mice (1283±79.15) compared to WT animals (495.4±53.96). However, no regeneration was observed in the Gal-3-/- mice two weeks after lesion. Furthermore, axonal degeneration presented a particular pattern on those mice; Electron Microscopy (EM) analysis showed incomplete axon degeneration while the WT mice presented an advanced stage of degeneration. This sugges...
Journal of Cell Science & Therapy, 2015
Revista Pesquisa em Fisioterapia, 2013
Introdução: A mobilização neurodinâmicaé indicada em uma série de condições que afetam o nervo pe... more Introdução: A mobilização neurodinâmicaé indicada em uma série de condições que afetam o nervo periférico, mas pouco se conhece sobre seus efeitos regenerativos.Objetivos: Descrever como a mobilização neurodinâmica pode interferir nas propriedades fisiológicas e mecânicas do nervo.Métodos: Esta revisão narrativa incluiu artigos registrados entre 1973 e 2012 no PubMed, escritos na língua Portuguesa e Inglesa e livros envolvendo estes tópicos. Discussão e Conclusão: Após uma lesão nervosa periférica uma série de eventos podem influenciar a regeneração, incluindo transporte axonal e movimento de fluidos, a carga mecânica aplicada no tecido neural e no tipo de lesão. Estes aspectos podem ser influenciados pela mobilização neurodinâmica. A dose, incluindo a magnitude da carga, velocidade e tempo são fatores que devem ser modulados para uma resposta ótima, enquanto a tensão, imobilidade ou hipomobilidade, podem ter efeitos negativos sobre a recuperação.
Experimental neurology, Jan 14, 2015
Spinal cord injury (SCI) is a traumatic event that results in motor, sensitive or autonomic funct... more Spinal cord injury (SCI) is a traumatic event that results in motor, sensitive or autonomic function disturbances, which have direct impact on the life quality of the affected individual. Recent studies have shown that attenuation of the inflammatory response after SCI plays a key role in the reestablishment of motor function. Galectin-3 is a pleiotropic molecule belonging to the carbohydrate-ligand lectin family, which is expressed by different cells in different tissues. Studies have shown that galectin-3 induces the recruitment and activation of neutrophils, monocytes/macrophages, lymphocytes and microglia. Thus, the aim of this study was to evaluate the effects of the lack of galectin-3 on the functional outcome, cellular recruitment and morphological changes in tissue, after SCI. C57BL/6wild-type and galectin-3 knockout mice were used in this study. A vascular clip was used for 1min to generate a compressive SCI. By BMS we detected that the Gal-3(-/-) presented a better functio...
Mediators of Inflammation, 2015
Traumatic injury to the central nervous system (CNS) or the peripheral nervous system (PNS) trigg... more Traumatic injury to the central nervous system (CNS) or the peripheral nervous system (PNS) triggers a cascade of events which culminate in a robust inflammatory reaction. The role played by inflammation in the course of degeneration and regeneration is not completely elucidated. While, in peripheral nerves, the inflammatory response is assumed to be essential for normal progression of Wallerian degeneration and regeneration, CNS trauma inflammation is often associated with poor recovery. In this review, we discuss key mechanisms that trigger the inflammatory reaction after nervous system trauma, emphasizing how inflammations in both CNS and PNS differ from each other, in terms of magnitude, cell types involved, and effector molecules. Knowledge of the precise mechanisms that elicit and maintain inflammation after CNS and PNS tissue trauma and their effect on axon degeneration and regeneration is crucial for the identification of possible pharmacological drugs that can positively af...
Journal of Cell Science & Therapy, 2014
Overview of Nerve Degeneration and Regeneration Nerve damage produces a well characterized cascad... more Overview of Nerve Degeneration and Regeneration Nerve damage produces a well characterized cascade of cellular and molecular events, described as Wallerian degeneration, throughout the distal stump. This process involves several phases, some concurrent, others consecutive, in which the distal stump degenerates; the myelin associated with degenerating axons are degraded and removed by Schwann cells (SC), and blood-recruited macrophages. SC can dedifferentiate, proliferate and align within the basal lamina tubes, called Bügner bands, which may subsequently be penetrated by regrowing axons. Once the SC-axon attachment is re-established, the remyelination process begins [1]. Growth cones emerge from the proximal stump of severed axons, induced by local factors released in response to the injury [2-4] and elongate if they find a favorable environment. It is known that regeneration of injured axons following trauma depends on a delicate balance between growth-promoting and growth-inhibiting factors. Several neurotrophic factors, cytokines, extracellular matrix molecules and hormones are secreted by neurons, SC, macrophages, the target tissue and cells present in the injury site, promoting neuronal survival, thus creating a permissive microenvironment for axon regeneration [5]. In this sense, SC in the vicinity of the transected axon synthesize a variety of growth factors including glial-derived neurotrophic factor (GDNF), insulin-like growth factor (IGF-1), and nerve growth factor (NGF), which have effects on axon growth [6]. The neurotrophins (NTs) family, which includes the brain-derived neurotrophic factor (BDNF), NGF and NTs 3 and 4/5, also play a crucial role in the regeneration process, serving as molecular cues and activators of the key signaling pathways that will support neuronal survival and growth [7].
World journal of stem cells, Jan 26, 2014
Mesenchymal stem cell (MSC) therapy has attracted the attention of scientists and clinicians arou... more Mesenchymal stem cell (MSC) therapy has attracted the attention of scientists and clinicians around the world. Basic and pre-clinical experimental studies have highlighted the positive effects of MSC treatment after spinal cord and peripheral nerve injury. These effects are believed to be due to their ability to differentiate into other cell lineages, modulate inflammatory and immunomodulatory responses, reduce cell apoptosis, secrete several neurotrophic factors and respond to tissue injury, among others. There are many pre-clinical studies on MSC treatment for spinal cord injury (SCI) and peripheral nerve injuries. However, the same is not true for clinical trials, particularly those concerned with nerve trauma, indicating the necessity of more well-constructed studies showing the benefits that cell therapy can provide for individuals suffering the consequences of nerve lesions. As for clinical trials for SCI treatment the results obtained so far are not as beneficial as those des...
Restorative neurology and neuroscience, 2015
Despite substantial advances in surgical care and rehabilitation, the consequences of spinal cord... more Despite substantial advances in surgical care and rehabilitation, the consequences of spinal cord injury (SCI) continue to present major challenges. Here we investigate whether transplantation of mesenchymal stem cells (MSCs) in mice during the chronic stage of SCI has benefits in terms of morphological and functional outcomes. Mice were subjected to laminectomy at the T9 level, followed by a 1 minute spinal cord compression with a vascular clip. Four weeks later, 8 × 105 MSCs obtained from GFP mice were injected into the injury site. After eight weeks the analyses were performed. The spinal cords of MSC-treated animals exhibited better white-matter preservation, greater numbers of fibers, higher levels of trophic factor expression, and better ultrastructural tissue organization. Furthermore, transplanted MSCs were not immunoreactive for neural markers, indicating that these cells mediate functional recovery through a paracrine effect, rather than by transforming into and replacing ...
BioMed Research International, 2014
We investigated the effect of two frequencies of transcutaneous electrical nerve stimulation (TEN... more We investigated the effect of two frequencies of transcutaneous electrical nerve stimulation (TENS) applied immediately after lesion on peripheral nerve regeneration after a mouse sciatic crush injury. The animals were anesthetized and subjected to crushing of the right sciatic nerve and then separated into three groups: nontreated, Low-TENS (4 Hz), and High-TENS (100 Hz). The animals of Low- and High-TENS groups were stimulated for 2 h immediately after the surgical procedure, while the nontreated group was only positioned for the same period. After five weeks the animals were euthanized, and the nerves dissected bilaterally for histological and histomorphometric analysis. Histological assessment by light and electron microscopy showed that High-TENS and nontreated nerves had a similar profile, with extensive signs of degeneration. Conversely, Low-TENS led to increased regeneration, displaying histological aspects similar to control nerves. High-TENS also led to decreased density o...
Stem Cells and Cancer Stem Cells, Volume 5, 2012
Toxicon, 2013
In this work we evaluated the ability of suramin, a polysulfonated naphthylurea derivative, to an... more In this work we evaluated the ability of suramin, a polysulfonated naphthylurea derivative, to antagonize the cytotoxic and enzymatic effects of the crude venom of Apis mellifera. Suramin was efficient to decrease the lethality in a dose-dependent way. The hemoconcentration caused by lethal dose injection of bee venom was abolished by suramin (30 μg/g). The edematogenic activity of the venom (0.3 μg/g) was antagonized by suramin (10 μg/g) in all treatment protocols. The changes in the vascular permeability caused by A. mellifera (1 μg/g) venom were inhibited by suramin (30 μg/g) in the pre- and posttreatment as well as when the venom was preincubated with suramin. In addition, suramin also inhibited cultured endothelial cell lesion, as well as in vitro myotoxicity, evaluated in mouse extensor digitorum longus muscle, which was inhibited by suramin (10 and 25 μM), decreasing the rate of CK release, showing that suramin protected the sarcolemma against damage induced by components of bee venom (2.5 μg/mL). Moreover, suramin inhibited the in vivo myotoxicity induced by i.m. injection of A. mellifera venom in mice (0.5 μg/g). The analysis of the area under the plasma CK vs. time curve showed that preincubation, pre- and posttreatment with suramin (30 μg/g) inhibited bee venom myotoxic activity in mice by about 89%, 45% and 40%, respectively. Suramin markedly inhibited the PLA2 activity in a concentration-dependent way (1-30 μM). Being suramin a polyanion molecule, the effects observed may be due to the interaction of its charges with the polycation components present in A. mellifera bee venom.
Journal of the Peripheral Nervous System, 2009
The use of electromagnetic fields has been reported to enhance peripheral nerve regeneration. Thi... more The use of electromagnetic fields has been reported to enhance peripheral nerve regeneration. This study aimed to identify the effects of a prolonged protocol of low-frequency pulsed electromagnetic field (PEMF) on peripheral nerve regeneration. Thirty-four male Swiss mice (Mus musculus) were divided into PEMF (n = 17) and control (n = 17) groups. All animals underwent a unilateral sciatic-crush lesion, and the PEMF group was exposed to a 72-Hz, 2-G electromagnetic field for 30 min, five days a week, for three weeks. Functional analysis was carried out weekly. After three weeks, the animals were euthanized, and histological, morphometric, oxidative stress, and TGF-β1 analyses were performed. Functional analysis showed no differences between the groups. Histological appearance was similar between PEMF and control nerves. Morphometric assessment showed that the PEMF nerves trended toward decreased regeneration. The levels of free radicals were more pronounced in PEMF nerves, but were not associated with an increase in the content of the TGF-β1/Smad signaling pathway. Prolonged PEMF regimen leads to delayed histological peripheral nerve regeneration and increased oxidative stress but no loss of function recovery.
Journal of Neuroscience Research, 2004
The ultrastructural change that characterizes the onset of Wallerian degeneration is the disinteg... more The ultrastructural change that characterizes the onset of Wallerian degeneration is the disintegration of axoplasmic microtubules and neurofilaments, which are converted into an amorphous and granular material, followed by myelin breakdown. The mechanism underlying such processes is an increase in the amount of intracellular calcium, leading to activation of proteases called calpains. The aim of this study was to evaluate by quantitative ultrastructural analysis whether nerve fibers can be preserved by the use of an exogenous inhibitor of these proteases (calpain inhibitor‐2, Mu‐F‐hF‐FMK), after optic nerve crush. For that, the left optic nerves of opossums, Didelphis aurita, were crushed with the aid of a fine forceps, and half of them received a calpain inhibitor mixed with Elvax resin. Ninety‐six hours after the lesion, the animals were reanesthetized and transcardially perfused, and the optic nerves were removed, the right ones being used as normal nerves. Afterward, the optic ...
Journal of Neuroscience Methods, 2009
Spinal cord injury (SCI) causes motor and sensory deficits that impair functional performance, an... more Spinal cord injury (SCI) causes motor and sensory deficits that impair functional performance, and significantly impacts life expectancy and quality. Animal models provide a good opportunity to test therapeutic strategies in vivo. C57BL/6 mice were subjected to laminectomy at T9 and compression with a vascular clip (30 g force, 1 min). Two groups were analyzed: injured group (SCI, n = 33) and laminectomy only (Sham, n = 15). Locomotor behavior (Basso mouse scale-BMS and global mobility) was assessed weekly. Morphological analyses were performed by LM and EM. The Sham group did not show any morphofunctional alteration. All SCI animals showed flaccid paralysis 24 h after injury, with subsequent improvement. The BMS score of the SCI group improved until the intermediate phase (2.037 ± 1.198); the Sham animals maintained the highest BMS score (8.981 ± 0.056), p < 0.001 during the entire time. The locomotor speed was slower in the SCI animals (5.581 ± 0.871) than in the Sham animals (15.80 ± 1.166), p < 0.001. Morphological analysis of the SCI group showed, in the acute phase, edema, hemorrhage, multiple cavities, fiber degeneration, cell death and demyelination. In the chronic phase we observed glial scarring, neuron death, and remyelination of spared axons by oligodendrocytes and Schwann cells. In conclusion, we established a simple, reliable, and inexpensive clip compression model in mice, with functional and morphological reproducibility and good validity. The availability of producing reliable injuries with appropriate outcome measures represents great potential for studies involving cellular mechanisms of primary injury and repair after traumatic SCI.
Journal of Neuroscience Methods, 2007
Among the numerous ways of assessing regeneration after peripheral nerve lesions, the analysis of... more Among the numerous ways of assessing regeneration after peripheral nerve lesions, the analysis of gait is one of the most important, because it shows the recovery of function, which is the ultimate goal of the repair machinery. The sciatic function index was introduced as a method to assess reinnervation after an experimental sciatic nerve lesion, and was adapted to the mouse model. The sciatic static index (SSI), is more simple and practical to perform, and is not so influenced by gait's velocity, but this method has not yet been adapted to the mouse model of sciatic lesion. We used 63 male Swiss mice (Mus musculus) to develop a formula to the sciatic static index in mice (SSIm). The animals were divided on three groups (control, transection and crush). They were evaluated at the preoperative and 7th, 14th, 21st, 28th, 35th and 42nd days postoperative by the ink track method (SFI), and by the acquisition of photographs of the plantar aspects of the injured and uninjured hind paws. The parameters evaluated were the 1-5 toe spread (TS), the 2-4 toe spread (ITS) and the distance between the tip of the third toe and the most posterior aspect of the paw (PL), on both methods. After verifying the temporal pattern of function, correlation and reproducibility of the measurements, we performed a multiple regression analysis using SFI values as dependent variable, and the TS, ITS and PL measured with the photo method as independent variables, and found the formula of the SSI for mice (SSIm). The three groups (control, transection and crush) had a characteristic pattern of dysfunction. The parameters measured in the ink and photo method had variable but significant correlations between them (P < 0.000), but photo method of measurement showed a better reproducibility. The correlation between SFI and SSIm showed a high correlation coefficient (r = 0.892, P < 0.000), and demonstrates that SSIm can be used as an alternative method to assess the functional status relative of sciatic nerve activity in mice.
Experimental Neurology, 2006
We evaluated peripheral nerve regeneration using a tubular nerve guide of resorbable collagen fil... more We evaluated peripheral nerve regeneration using a tubular nerve guide of resorbable collagen filled with either bone marrow-derived cells (BMDCs) in Dulbecco's cell culture medium (DMEM) or with DMEM alone (control). The control group received just the culture medium (vehicle). The left sciatic nerves of ten isogenic mice were transected and the tubular nerve guides were sutured to the end of the proximal and distal nerve stumps. Motor function was tested at 2, 4 and 6 weeks after surgery using the walking track test. The pawprints were analyzed and the print lengths (PL) were measured to evaluate functional recovery. After 6 weeks, mice were anesthetized, perfused transcardially with fixative containing aldehydes, and the sciatic nerves and tubes were dissected and processed for scanning and transmission electron microscopy. Scanning electron microscopy of the collagen tube revealed that the tube wall became progressively thinner after surgery, proving that the tube can be resorbed in vivo. Quantitative analysis of the regenerating nerves showed that the number of myelinated fibers and the myelin area were significantly increased in the experimental group. Also, motor function recovery was faster in animals that received the cell grafts. These results indicate that the collagen tube filled with BMDCs provided an adequate and favorable environment for the growth and myelination of regenerating axons compared to the collagen tube alone.
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Papers by Ana Maria Blanco Martinez