Stem cells are undifferentiated cells with the ability to divide and differentiate into distinct cell types. The source of these cells is from embryos and adults, that each cell has its own specific characteristics. For nearly decades, experimental studies have been conducted to use these types of cells to treat various diseases. Parkinson's disease is one of the most common neurodegenerative diseases, resulting in a deficiency of dopaminergic neurons. Therefore, we study the role of stem cell therapies in the treatment of Parkinson's disease. Initially, 73 relevant articles selected from valid databases such as ISC, SID, Google Scholar and PubMed and the role of each type of stem cell in the treatment of Parkinson's disease was collected. Stem cells can be used in experimental studies regard to the unique characteristics and using different laboratory agents for any particular type of cells. Stem cells can provide an unlimited source of dopaminergic neurons for transplantation and improve motor behavior and symptoms of Parkinson's disease. Study and comparison of different types of stem cells refer to the more effective role of neural and umbilical stem cells in treating Parkinson's disease.

Introduction: As adipose tissue-derived stem cells (ADSCs) can divide rapidly and be prepared non-invasively, they have extensively been used in regenerative medicine. On the other hand, a new method of therapy, known as photobiomodulation (PHT), has been used to treat many diseases, such as inflammatory conditions, wound healing and pain. Besides, exposure to chemical substances such as bisphenol A (BPA), at low levels, can lead to autophagy. This study investigated the effects of BPA and PHT on the expression of autophagy-related genes, including LC3, NRF2, P62, in rat ADSCs as a model. Methods: ADSCs isolation and purification were confirmed by immunocytochemistry (ICC). The cells were then treated with different concentrations of BPA and also subjected to PHT. Reverse transcription polymerase chain reaction (RT-PCR) was used for the evaluation of LC3, NRF2 and P62 gene expressions. Oil red O staining was used for adipogenic vacuole formation. Result: ICC showed that the isolated cells were CD 49-positive but CD 31 and CD 34-negative. The viability test indicated that the number of live cells after 24 hours in the BPA groups at concentrations of 0, 1, 50, 100 and 200 μM was 100%, 93%, 81%, 72%, and 43% respectively. The difference in cell viability between groups 50, 100 and 200 μM was significant as compared with the control groups (P<0.05). Moreover, in the group with 1 μM concentration of BPA, the expressions of LC3, NRF2 and P62 genes were upregulated. However, in the treatment group at the concentration of 200 μM of BPA, the LC3 gene was expressed, but NRF2 and P62 genes were downregulated. Conclusion: BPA and PHT induce autophagy and adiposeness in ADSCs in a dose-dependent manner.

Introduction: Alzheimer disease (AD), known to be a leading cause of dementia that causes heavy social and financial burdens worldwide, characterized by progressive loss of neurons and synaptic connectivity after depositions of amyloid-β (Aβ) protein.AD manifests as an impaired ability to comprehend or use words, poor coordination and gait, and impaired executive functions in the realms of planning, ordering and making judgments. Generally, classification of AD includes familial and sporadic AD. Current therapies for AD patients can only alleviate symptoms, but cannot deter the neural degeneration, thus providing no long-term recovery. Stem cells are undifferentiated cells that have a potential to produce many different cell types in the body. A vast amount of data indicates the potential of stem cell therapy for various neurological diseases. Several studies revealed that neurons and glial cells have successfully been differentiated from various stem cells. Thus, in this article, we review the treatment of Alzheimer\ disease by various types of stem cells.