In Vivo Evaluation of Collagen and Chitosan Scaffold, Associated or Not with Stem Cells, in Bone Repair.

Natural polymers are increasingly being used in tissue engineering due to their ability to mimic the extracellular matrix and to act as a scaffold for cell growth, as well as their possible combination with other osteogenic factors, such as mesenchymal stem cells (MSCs) derived from dental pulp, in an attempt to enhance bone regeneration during the healing of a bone defect. Therefore, the aim of this study was to analyze the repair of mandibular defects filled with a new collagen/chitosan scaffold, seeded or not with MSCs derived from dental pulp. Twenty-eight rats were submitted to surgery for creation of a defect in the right mandibular ramus and divided into the following groups: G1 (control group; mandibular defect with clot); G2 (defect filled with dental pulp mesenchymal stem cells-DPSCs); G3 (defect filled with collagen/chitosan scaffold); and G4 (collagen/chitosan scaffold seeded with DPSCs). The analysis of the scaffold microstructure showed a homogenous material with an adequate percentage of porosity. Macroscopic and radiological examination of the defect area after 6 weeks post-surgery revealed the absence of complete repair, as well as absence of signs of infection, which could indicate rejection of the implants. Histomorphometric analysis of the mandibular defect area showed that bone formation occurred in a centripetal fashion, starting from the borders and progressing towards the center of the defect in all groups. Lower bone formation was observed in G1 when compared to the other groups and G2 exhibited greater osteoregenerative capacity, followed by G4 and G3. In conclusion, the scaffold used showed osteoconductivity, no foreign body reaction, malleability and ease of manipulation, but did not obtain promising results for association with DPSCs.

Characterization of traumatic spinal cord injury model in relation to neuropathic pain in the rat.

Purpose/aim: Neuropathic pain following spinal cord injury (SCI) has a tremendous impact on patient's quality of life, and frequently is the most limiting aspect of the disease. In view of the severity of this condition and the absence of effective treatments, the establishment of a reliable animal model that reproduces neuropathic pain after injury is crucial for a better understanding of the pathophysiology and for the development of new therapeutic strategies. Thus, the objective of the present study was to standardize the traumatic SCI model in relation to neuropathic pain. MATERIALS AND METHODS: Wistar rats were submitted to SCI of mild intensity (pendulum height 12.5 mm) or moderate intensity (pendulum height 25 mm) using the New York University Impactor equipment. Behavioural assessment was performed during 8 weeks. Thereafter, spinal cords were processed for immunohistochemistry. RESULTS: The animals of the moderate injury group in comparison with mild injury had a greater motor function deficit, worse mechanical allodynia, and latter bladder recovery; moreover, histological analysis revealed more extensive lesions with lower neuronal population. CONCLUSIONS: Our study suggests that moderate SCI causes a progressive and long-lasting painful condition (at least 8 weeks), in addition to motor impairment, and thus represents a reliable animal model for the study of chronic neuropathic pain after SCI.

Adult stem cells in neural repair: Current options, limitations and perspectives.

Stem cells represent a promising step for the future of regenerative medicine. As they are able to differentiate into any cell type, tissue or organ, these cells are great candidates for treatments against the worst diseases that defy doctors and researchers around the world. Stem cells can be divided into three main groups: (1) embryonic stem cells; (2) fetal stem cells; and (3) adult stem cells. In terms of their capacity for proliferation, stem cells are also classified as totipotent, pluripotent or multipotent. Adult stem cells, also known as somatic cells, are found in various regions of the adult organism, such as bone marrow, skin, eyes, viscera and brain. They can differentiate into unipotent cells of the residing tissue, generally for the purpose of repair. These cells represent an excellent choice in regenerative medicine, every patient can be a donor of adult stem cells to provide a more customized and efficient therapy against various diseases, in other words, they allow the opportunity of autologous transplantation. But in order to start clinical trials and achieve great results, we need to understand how these cells interact with the host tissue, how they can manipulate or be manipulated by the microenvironment where they will be transplanted and for how long they can maintain their multipotent state to provide a full regeneration.

Intraoperative assistive technologies and extent of resection in glioma surgery: a systematic review of prospective controlled studies.

Several studies published to date about glioma surgery have addressed the validity of using novel technologies for intraoperative guidance and potentially improved outcomes. However, most of these reports are limited by questionable methods and/or by their retrospective nature. In this work, we performed a systematic review of the literature to address the impact of intraoperative assistive technologies on the extent of resection (EOR) in glioma surgery, compared to conventional unaided surgery. We were also interested in two secondary outcome variables: functional status and progression-free survival. We primarily used PubMed to search for relevant articles. Studies were deemed eligible for our analysis if they (1) were prospective controlled studies; (2) used EOR as their primary target outcome, assessed by MRI volumetric analysis; and (3) had a homogeneous study population with clear inclusion criteria. Out of 493 publications identified in our initial search, only six matched all selection criteria for qualitative synthesis. Currently, the evidence points to 5-ALA, DTI functional neuronavigation, neurophysiological monitoring, and intraoperative MRI as the best tools for improving EOR in glioma surgery. Our sample and conclusions were limited by the fact that studies varied in terms of population characteristics and in their use of different volumetric analyses. We were also limited by the low number of prospective controlled trials available in the literature. Additional evidence-based high-quality studies assessing cost-effectiveness should be conducted to better determine the benefits of intraoperative assistive technologies in glioma surgery.

Current perspectives in stem cell therapy for spinal cord repair in humans: a review of work from the past 10 years.

UNLABELLED: Spinal cord injury (SCI) and amyotrophic laterals sclerosis (ALS) are devastating neurological conditions that affect individuals worldwide, significantly reducing quality of life, both for patients and their relatives. OBJECTIVE: The present review aims to summarize the multiple restorative approaches being developed for spinal cord repair, the use of different stem cell types and the current knowledge regarding stem cell therapy. METHOD: Review of the literature from the past 10 years of human studies using stem cell transplantation as the main therapy, with or without adjuvant therapies. CONCLUSION: The current review offers an overview of the state of the art regarding spinal cord restoration, and serves as a starting point for future studies.

Stem cells in neurology--current perspectives.

UNLABELLED: Central nervous system (CNS) restoration is an important clinical challenge and stem cell transplantation has been considered a promising therapeutic option for many neurological diseases. OBJECTIVE: The present review aims to briefly describe stem cell biology, as well as to outline the clinical application of stem cells in the treatment of diseases of the CNS. METHOD: Literature review of animal and human clinical experimental trials, using the following key words: "stem cell", "neurogenesis", "Parkinson", "Huntington", "amyotrophic lateral sclerosis", "traumatic brain injury", "spinal cord injury", "ischemic stroke", and "demyelinating diseases". CONCLUSION: Major recent advances in stem cell research have brought us several steps closer to their effective clinical application, which aims to develop efficient ways of regenerating the damaged CNS.

Current perspectives in stem cell therapy for spinal cord repair in humans: a review of work from the past 10 years / Atuais perspectivas da terapia com células tronco para regeneração medular em humanos: um revisão de trabalhos dos últimos 10 anos

Spinal cord injury (SCI) and amyotrophic laterals sclerosis (ALS) are devastating neurological conditions that affect individuals worldwide, significantly reducing quality of life, both for patients and their relatives. Objective : The present review aims to summarize the multiple restorative approaches being developed for spinal cord repair, the use of different stem cell types and the current knowledge regarding stem cell therapy. Method : Review of the literature from the past 10 years of human studies using stem cell transplantation as the main therapy, with or without adjuvant therapies. Conclusion : The current review offers an overview of the state of the art regarding spinal cord restoration, and serves as a starting point for future studies. .

Lesão medular (LM) e esclerose lateral amiotrófica (ELA) são condições devastadoras que acometem pessoas em todo o mundo, reduzindo a qualidade de vida tanto de pacientes como de entes queridos. Objetivo : A atual revisão tem como alvo as múltiplas abordagens restauradoras para a regeneração medular, o uso de diferentes tipos celulares e o atual conhecimento a cerca da terapia com células tronco. Método : Revisão de literatura dos últimos 10 anos usando transplantes de células tronco como estratégia principal, com ou sem terapia adjuvante, em humanos. Conclusão : A presente revisão oferece uma visão geral acerca da restauração medular e serve de ponto de partida para estudos futuros. .

Stem cells in neurology - current perspectives / Células-tronco em neurologia - perspectivas atuais

Central nervous system (CNS) restoration is an important clinical challenge and stem cell transplantation has been considered a promising therapeutic option for many neurological diseases. Objective : The present review aims to briefly describe stem cell biology, as well as to outline the clinical application of stem cells in the treatment of diseases of the CNS. Method : Literature review of animal and human clinical experimental trials, using the following key words: “stem cell”, “neurogenesis”, “Parkinson”, “Huntington”, “amyotrophic lateral sclerosis”, “traumatic brain injury”, “spinal cord injury”, “ischemic stroke”, and “demyelinating diseases”. Conclusion : Major recent advances in stem cell research have brought us several steps closer to their effective clinical application, which aims to develop efficient ways of regenerating the damaged CNS. .

Restauração do sistema nervoso central (SNC) é um importante desafio clínico e o transplante de células-tronco tem sido considerado uma opção terapêutica promissora para muitas doenças neurológicas. Objetivo : O presente trabalho tem como objetivo descrever brevemente a biologia das células-tronco, assim como sua aplicação clínica no tratamento de doenças do SNC. Método : Revisão da literatura de experimentação animal e ensaios clínicos com humanos, usando as seguintes palavras chave: “células-tronco”, “neurogênese”, “Parkinson”, “Huntington”, “esclerose lateral amiotrófica”, “lesão cerebral traumática”, “lesão da medula espinal”, “acidente vascular cerebral isquêmico” e “doenças desmielinizantes”. Conclusão : Grandes avanços em pesquisas com células-tronco nos conduziram a novas perspectivas para uma aplicação clínica efetiva, visando desenvolver formas eficazes de regeneração do SNC. .

Adult neurogenesis and glial oncogenesis: when the process fails.

Malignant brain tumors, including glioblastoma multiforme (GBM), are known for their high degree of invasiveness, aggressiveness, and lethality. These tumors are made up of heterogeneous cell populations and only a small part of these cells (known as cancer stem cells) is responsible for the initiation and recurrence of the tumor. The biology of cancer stem cells and their role in brain tumor growth and therapeutic resistance has been extensively investigated. Recent work suggests that glial tumors arise from neural stem cells that undergo a defective process of differentiation. The understanding of this process might permit the development of novel treatment strategies targeting cancer stem cells. In the present review, we address the mechanisms underlying glial tumor formation, paying special attention to cancer stem cells and the role of the microenvironment in preserving them and promoting tumor growth. Recent advancements in cancer stem cell biology, especially regarding tumor initiation and resistance to chemo- or radiotherapy, have led to the development of novel treatment strategies that focus on the niche of the stem cells that make up the tumor. Encouraging results from preclinical studies predict that these findings will be translated into the clinical field in the near future.