RESUMEN
In recent years, we have witnessed a significant increase in the amount of studies using Mesenchymal Stem Cells (MSCs) for cancer therapy, mostly as vectors for drug or gene delivery strategies. This is because of their intrinsic capacity of homing into tumor niches. However, the interactions between MSCs themselves and tumor cells is not fully understood, with contradictory results frequently being observed regarding their effects on cancer cell invasion and proliferation. This poses an important question of safety in respect to the application of these cells. The source of the MSC population used, as well as the type of cancer cells under study might strongly influence this interaction. Moreover, differences in isolation protocols, culture media compositions, time of culture and conditioned media collection, or even timing and mode of MSCs administration to in vivo models of cancer may also affect the interaction MSC-tumor cells. In this review, we drive our focus into malignant brain tumors, particularly gliomas, one of the deadliest forms of cancer. Moreover, we look with some detail into different studies using MSCs as a treatment for brain tumors and compare them, highlighting the main deviations and similarities among them.
Asunto(s)
Neoplasias Encefálicas/metabolismo , Técnicas de Transferencia de Gen , Glioma/terapia , Trasplante de Células Madre Mesenquimatosas , Animales , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Glioma/genética , Glioma/metabolismo , Glioma/patología , Humanos , Células Madre Mesenquimatosas , Invasividad NeoplásicaRESUMEN
Mesenchymal stem cells (MSCs) have been proposed for spinal cord injury (SCI) applications due to their capacity to secrete growth factors and vesicles-secretome-that impacts important phenomena in SCI regeneration. To improve MSC survival into SCI sites, hydrogels have been used as transplantation vehicles. Herein, we hypothesized if different hydrogels could interact differently with adipose tissue-derived MSCs (ASCs). The efficacy of three natural hydrogels, gellan gum (functionalized with a fibronectin peptide), collagen, and a hydrogel rich in laminin epitopes (NVR-gel) in promoting neuritogenesis (alone and cocultured with ASCs), was evaluated in the present study. Their impact on ASC survival, metabolic activity, and gene expression was also evaluated. Our results indicated that all hydrogels supported ASC survival and viability, being this more evident for the functionalized GG hydrogels. Moreover, the presence of different ECM-derived biological cues within the hydrogels appears to differently affect the mRNA levels of growth factors involved in neuronal survival, differentiation, and axonal outgrowth. All the hydrogel-based systems supported axonal growth mediated by ASCs, but this effect was more robust in functionalized GG. The data herein presented highlights the importance of biological cues within hydrogel-based biomaterials as possible modulators of ASC secretome and its effects for SCI applications.
RESUMEN
Past trials with soft and calcified tissues have demonstrated that long pulse train (2.5 mus) Er:YAG (2.94 mum) laser may be used to ablate tooth structure of human teeth. Determination of physical and thermal damage to surrounding tissue during removal of enamel and dentin is a primary objective of this study. Extracted human teeth with thermal probes imbedded in the pulp chambers were submitted to cavity preparation using an Erbium YAG laser with water mist. Wavelength selection as well as use of a water mist during the procedure resulted in efficient tissue removal without significant surrounding damage. Ground sections and SEM sections of teeth showed little or no melting or ash formation in adjacent dentin and enamel and no visible change in the pulp chamber. The surfaces produced by laser ablation were rough and irregular with craters and grooves. Average temperature change in the pulp chamber monitored during tooth preparation was 2.2 degrees Centigrade. These findings suggest that constantly available water aids vaporization and microexplosions, increasing the efficiency of tooth structure removal, and aids in cooling of the tooth structures. The long pulse Er:YAG (2.94 mum) laser may be an effective method for tooth reduction applications when used with a water mist.
