The key words that were include ELISA, VEGF, NGF, stem cell, sciatic, umbilical cord, and mesenchymal stem cells.
Some of the phrases that were used
Comparison of ELISA examination of VEGF and NGF, Comparison of ELISA examination of VEGF and NGF in conditioned medium in umbilical cord derived mesenchymal stem cell in sciatic injury, VEGF vs NGF.
Filtering of results
The results were filtered using the method that if there was no mention of VEGF or NGF, it would not be useful. It was important to have results which would mention VEGF and NGF. Also of significant importance was the need to have results that mentioned mesenchymal stem cell.
One of the promising cell-based strategies for enhancing peripheral nerve regeneration is cell-based therapy. The cells that are common in cell-based therapies are Schwann and mesenchymal stem cells (MSCs) and are commonly seen to be used in injuries of the neural system and disorders. There are limitations that come with the use of Schwann cells, even though they are commonly used in tissue grafting as a support cell (Funakoshi, Lee, & Hsieh, 2014). These limitations include the fact that autologous Schwann cells are hard to come by and amplify, and also that they lose their phenotypic features at faster rates. On the other hand, MSCs are known to be multipotent, and will work for specific tissues. They become easily isolated in the process of grafting. They also have features like exerting trophic, anti-inflammatory, and immunomodulatory effects. These are desirable characteristics which have made MSC the most preferred MSC for use as a support cell when undertaking cell-based therapy and also when used for treating neurological diseases (Funakoshi, Lee, & Hsieh, 2014). This paper will focus on comparison of ELISA examination of VEGF and NGF.
The bone marrow is the only autologous source of MSCs which are used to treat injuries to the nerve. There has been the use of human bone marrow mesenchymal stem cell transplantation in the treatment of neurological disease in many clinical trials that have been done in the past. These trials gave encouraging results that would be used in the long- or short-term (Guo, Sun, Xu, Zhao, Peng, & Wang, 2015). One challenge, however, is that some patients may not be able to use their own cells because of some factors like age or some disease that is underlying. Human umbilical cord-derived MSCs (hUCMSCs) represent a cell type that is considered to be young and have higher rates of proliferation and have higher propensity for expansion when they are compared to the bone marrow mesenchymal stem cells in vitro. hUCMSCs are considered to be an alternative source of bone marrow mesenchymal stem cells because they have good and reliable intrinsic features, example is that of the ability to renew at a higher rate when compared to stem cells from other locations. Their use is ethically less problematic, abundantly available, and they are known to be hypo-immunogenic as well as non-tumorigenic (Ke, & Zhang, 2013). There are many clinical trials that have been done to see the probability of undertaking treatment with hUCMSCs and it has been proven to have a higher rate of efficacy and safety. It has proved to treat many neurological diseases.
Although the use of MSCs have been described to be the gold standard that can be used in the area of bone formation. There has been the development of the possibility to isolate cells which are multipotent from the list of tissues that are growing, when they have been deemed to be wasteful surgically (Lahiani, Zahavi, Netzer, Ofir, Pinzur, Raveh, & Lazarovici, 2015). These tissues include adipose, deciduous teeth, and tissues that are associated with birth, including the umbilical cord and the placenta. The methods that are used to undertake isolation for these tissues are known to be less invasive when they care compared to MSCs, therefore, support the recovery process for the patients. Also, depending on the application that is used, these cells may be found to be more effective in the therapeutic process than MSCs.
ELISA examination with VEGF
The responsiveness of VEGF is very important the functioning and maintenance of angiogenic cell, and also important in other parts of the body like that of wound healing and normal functioning of the tissues. The regulation of the rate of responsiveness and be done and achieved through several points with the use of cells which are VEGF-responsive through the method of using different receptor expression (Liu, Zhang, He, Hong, Chen, Peng, & Jiang, 2014). When VEGF and VEGFR2 are bond, there is the migration and proliferation. This migration can be associated with neoropilin binding with VEGF. The VEGFR-1, which is produced in both the membrane-bound signaling and that of decoy soluble form, is thought to be the force that goes against this effect through binding VEGF tightly. The binding of VEGFR-1 through the membrane will give weak signals despite the high affinity it has for the VEGF. This results in sequestering excessive amounts of molecule (Liu, Zhang, He, Hong, Chen, Peng, & Jiang, 2014). The change in the relative amount of surface-expression in all the receptors that are in use is known to change the responsiveness of the cells that are targeted to VEGF therapies. This has been observed and noted in models that are used in cancer.
The present research and work have confirmed the production, via gene expression, of VEGF by MSCs and MPCs. This production has been achieved through sandwich ELISA analysis of CM. on the other hand, the production of IL-1b, FGF-2, and that of PDGF by the two types of cells have been seen to be consistent and in order. This process was also not detectable. The secretone from MPC also came out to have a net positive effect on the way the EC cords were organized in vitro (Funakoshi, Lee, & Hsieh, 2014). There was the abrogation of the effect by siRNA silencing that was done to VEGF. VEGF which was excreted by MSC was seen not to alter the net-zero effect of MSC-CM on the EC microvascular network in this entire process. In order to have an assessment of whether MPCs were suitable to be used in vivo, there was the encapsulation of MPCs and then cultured in vivo, within the mechanically tunable, hydrogel scaffold which had been photocrosslinked. Through this process, there was a number of encapsulated MPCs which came out to survive and then they continued to produce VEGF. Although, while there was the toleration of encapsulation by MSCs, the production of MSC-VEGF was seen to have a decline for a given period of time. After a period of two days while staying on the surface of CAM, it was found out that a majority of the cells which had been encapsulated were still viable, and that relatively few of the cells of the CAM had migrated to each of the constructs. MPCs were seen to have more capacities for capillary recruitment, which is consistent with in vitro assays, when they were compared to MSCs. However, this activity was no longer dependent on VEGF (Guo, Sun, Xu, Zhao, Peng, & Wang, 2015). There was the ruling out of CAM inflammation that had cell non-specificity or those that were regulated by hydrogel. This rule out was done because there was lack of response that was associated with CAM to HFFs which had been encapsulated.
In this process, there was the realization that VEGF is potent and highly-expressed antigenic molecule that has been seen to affect the migration of endothelial cells. Other functions include proliferation, formation of tubes, and other functions. When there is the coordination of this process together with other molecules, EC functions which are associated with VEGF changes, will result in angiogenesis, which is the formation of new vessel extensions that are done to vasculature which exist (Guo, Sun, Xu, Zhao, Peng, & Wang, 2015). Apart from MSCs which are associated with VEGF, MSCs which are serum-starved or otherwise-activated, are known to produce many molecules that are able to modify or undertake mask the effect that is produced by VEGF on the process of angiogenesis and that of wound-healing. They include ANGPT-1, HGF, SDF-1, IGF-1, FGF-1, and PDGF, which are known to increase the proliferation of EC, at various stages and levels. They also variously increase other functions like migration, branching, or adhesion (Guo, Sun, Xu, Zhao, Peng, & Wang, 2015). Also, cytokines that have an effect on endothelial cells and the surrounding inflammatory cells, which include CCL-2, IL-1b, and IL-6 have the ability to help in the process of loosening of all the connections that are associated with EC-EC. This process enables the EC tip cells to sprout and enable the formation of nascent blood cells. Although this is the case, the molecules which have been secreted by MSCs, are not purely pro-angiogenic. There has been the observation of anti-angiogenic activity which have shown that there are many routes with which these activities can be mediated. These routes include through soluble, decoy forms of growth factor receptors, for example, the PDGF receptor, soluble VEGF receptors (for example sVEGFR-1 and SVEGFR-2) and also undertaken through some oxosomes/microparticles which are isolated from MSC-CM, and some of these components microRNA which are known to inhibit VEGF (Guo, Sun, Xu, Zhao, Peng, & Wang, 2015). Although they are less-characterized than MSCs, many of the mentioned pro-angiogenic factors, are known to be produced or expressed with the use of MPCs. There are similar gene expressions levels that have been done for IL-1b, IL-6, VEGF, and FGF-2 which were observed between the MPCs and MSCs. A comparative analysis for CM could come out with interesting differences that might be used to explain the differences in EC support activities that are done between MPCs and MSCs.
There has been the development of one model that is in vitro that is used for angiogenesis and it involves the process of sending of the ECs on the Matrigel that has the factor-reduced, or use a similar substrate which is rich in laminin and is able to observe EC network features (Ke, & Zhang, 2013). The assay that is code-forming, has been observed to have a complete description of networks that has been formed within the whole cell. It has also been observed that other in vitro angiogenesis models require manual choosing of areas where imaging could be done (Ke, & Zhang, 2013). This is known to bring experimental bias within the research or could be the source of endothelial cells which have no proper source. The EC cord-networks are known to exhibit a lot of dynamism, and that they are able to maintain high branched multicellular configurations when they are under the influence of pro-angiogenic factors. Given the fact that the ECs which have been used commonly in experiments have been derived from stably-transformed microvascular cell line, and also that there has been cord-formation against physiologically functional formation of the tubes were taken under assessment, it gives the possibility that the effects that are associated with angiogenic process in this case will not be transferred to an in vivo setting (Ke, & Zhang, 2013).
In order to have an in vitro and in vitro settings, there are many in vivo models which are under existence. However, each of the in vivo models will come with their own limitations. One of the highest priorities will be the cost that will come to the animal and the researcher. This is because there could be the possibility to have immunocompromised animals to be bred, and they have to be housed for the entire period that the exper...
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