8.2. Msc niche

Schofield 1978 first introduced a stem cell 'niche' term [52]. The niche consists of the elements surrounding the stem cells in their naïve state including the non-stem cells as well as ECM and soluble molecules found in that locale. The above factors act together to maintain the stem cells in their undifferentiated state. Differentiation of the stem cells needs certain signals which must find their way into the niche for the regeneration or repopulation of a tissue.

the tissue microenvironment in vivo and control the appropriate differentiation of stem cells is a promising approach to therapeutic applications. Molecular information on ECM–MSC interactions, involving integrins, which involved in niche biology in other systems [59], is clearly

Stromal Stem Cells: Nature, Biology and Potential Therapeutic Applications

http://dx.doi.org/10.5772/intechopen.77346

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MSCs are promising cell source for treatment of autoimmune, degenerative and inflammatory diseases due to the homing ability, multilineage potential, secretion of anti-inflammatory molecules and immunoregulatory effects. MSCs role in treating chronic diseases have been

MSCs are capable of differentiating into neurons [60]. An acid sphingomyelinase mouse model was used to conduct the first MSCs transplantation for neurodegenerative disorders. After MSCs injection, an amelioration in the overall survivability of the mouse and a decrease in disease abnormalities were detected [61]. Based on this study, a new study was performed in order to ensure the MSC transplantation efficiency in a neurodegenerative disease that leads to motor neurons degeneration and muscle function distortion, Amyotrophic lateral sclerosis (ALS) [61]. MSCs were isolated from the bone marrow and then reinjected into the spinal cord of the same patients, followed by MRI at 3 and 6 months for MSCs tracking. Results did not reveal any abnormal cells proliferation or structural changes in the spinal cord. However, mild adverse effects occurred which were reversed in few weeks duration e.g. intercostal pain irradiation and leg sensory dysesthesia. In another study, genetically modified AD-MSCs were made to express GDNF to be transplanted in a rat model of ALS, an increased number of neuromuscular connections and an improved pathological phenotype were observed [62].

Parkinson's disease (PD), a neurodegenerative disorder, characterized by significant loss of dopaminergic neurons. After MSCs transplantation in PD mice model, tyrosine hydroxylase level increased [63]. MSCs participate to neuroprotection by secretion of trophic factors like vascular endothelial growth factor (VEGF), EGF, FGF-2, neurotrophin-3 (NT3), HGF and BDNF without differentiating into neurocytes [64]. Genetically modified hMSCs are used to induce the secretions of specific factors or to increase the dopamine (DA) cell differentiation. BM-MSCs transduction with lentivirus carrying LMX1a gene, resulted in cells which were similar to mesodiencephalic neurons with high DA cell differentiation [65]. Experiments were performed on Parkinson diseased rat, the research group from the university hospital of Tubingen in Germany administered BM-MSCs nasally to treat neurodegenerative patients. MSCs were found in different brain regions after 4.5 months of administration. They have

needed.

9. Applications

9.1. Human mesenchymal stem cells and chronic diseases

extensively studied in animal disease model.

9.2. Amyotrophic lateral sclerosis

9.3. Parkinson's disease
