جستجوی مقالات مرتبط با کلیدواژه « Adult Stem Cells » در نشریات گروه « پزشکی »

Primordial germ cells develop into oocytes and sperm cells. These cells are useful resources in reproductive biology and regenerative medicine. The mesenchymal stem cells (MSCs) have been examined for in vitro production of primordial germ cell-like cells. This study aimed to summarize the existing protocols for MSCs differentiation into primordial germ cell-like cells (PGLCs). In the limited identified studies, various models of mesenchymal stem cells, including those derived from adipose tissue, bone marrow, and Wharton's jelly, have been successfully differentiated into primordial germ cell-like cells. Although the protocols of specification induction are basically very similar, they have been adjusted to the mesenchymal cell type and the species of origin. The availability of MSCs has made it possible to customize conditions for their differentiation into primordial germ cell-like cells in several models, including humans. Refining germ cell-related signaling pathways during induced differentiation of MSCs will help define extension to the protocols for primordial germ cell-like cells production.

The choice of an appropriate autogenous source of stem cells has not been adequately addressed especially for intraoral bone regeneration. The current review aims to assess the clinical success of various human stem cells in oral bone regeneration. Articles studying the potential of various stem cells utilized for reconstruction of intraoral bone defects in humans were included in this review. Relevant articles were electronically searched in MEDLINE-PubMed database using keywords with different combinations. Only the articles published in English between 2006 and 2020 were included in this review. It was concluded that intra and extraoral stem cells can be successfully used for bone regeneration of various jaw defects. Depending on the origin, quantity, and quality, each cell type has its own advantages and disadvantages. Also, it brings to the fore the need for more clinical studies to validate and adopt the use of stem cells in regular clinical practice.

 Stem cell-based treatment modalities have been potential strategies for tissue regenerationin many conditions. Several studies have evaluated the biologic properties of DPSCs and their efficacyin the treatment of a variety of diseases. The present study was undertaken to evaluate the adhesionbehavior of DPSCs on different endodontic materials before and after setting.

 The crowns of the selected teeth were removed, and the root canals were prepared andobturated with gutta-percha and AH26 sealer. A retrograde cavity was prepared at root ends. Differentmaterials were placed in the cavities. Then the samples were attached to the wells with the use of achemical glue. Dental pulp stem cells were allowed to proliferate to reach a count of 2 million andtransferred to -12well plates in association with a culture medium. Finally, the samples attached to thewells were exposed to the stem cells immersed in the culture medium before and after setting. Thenadhesion of the stem cells was evaluated using SEM.

 The SEM results showed cellular adhesion in the samples containing CEM cement both beforeand after setting. The samples containing MTA Angelus and ProRoot MTA exhibited cellular adhesionbefore setting, with no cellular adhesion after setting. The samples containing AH26 and MTA Fillapexsealers exhibited cellular adhesion after setting, with no adhesion before setting. The samples containingsimvastatin exhibited no cellular adhesion before setting; this material had dissolved in the culturemedium after setting evaluation.

The results of the present study showed that of all the materials tested, CEM cement hadthe highest capacity for dental pulp stem cell adhesion.

The use of stem cells, growth factors, and scaffolds to repair damaged tissues is a new idea in tissue engineering. The aim of the present study is the investigation of Avocado/soybean (A/S) effects on chondrogenic differentiation of human adipose‑derived stem cells (hADSCs) in micromass culture to access cartilage tissue with high quality.

In this an experimental study After hADSCs characterization, chondrogenic differentiation was induced using transforming growth factor beta 1 (TGF‑β1) (10 ng/ml) and different concentrations (5, 10, and 20 μg/ml) of A/S in micromass culture. The efficiency of A/S on specific gene expression (types I, II, and X collagens, SOX9, and aggrecan) was evaluated using quantitative polymerase chain reaction. In addition, histological study was done using hematoxylin and eosin and toluidine blue staining all data were analyzed using one‑way analysis of variance (ANOVA) and P ≤ 0.05 was considered to be statistically significant.

The results of this study indicated that A/S can promote chondrogenic differentiation in a dose‑dependent manner. In particular, 5 ng/ml A/S showed the highest expression of type II collagen, SOX9, and aggrecan which are effective and important markers in chondrogenic differentiation. In addition, the expression of types I and X collagens which are hypertrophic and fibrous factors in chondrogenesis is lower in present of 5 ng/ml A/S compared with TGF‑β1 group (P ≤ 0.05). Moreover, the sulfated glycosaminoglycans in the extracellular matrix and the presence of chondrocytes within lacuna were more prominent in 5 ng/ml A/S group than other groups.

It can be concluded that A/S similar to TGF‑β1 is able to facilitate the chondrogenic differentiation of hADSCs and do not have adverse effects of TGF‑β1. Thus, TGF‑β1 can be replaced by A/S in the field of tissue engineering.

The hematopoietic system is sensitive to the adverse effects of ionizing radiation. Cellular therapies utilizing mesenchymal stem cells or vascular endothelial cells have been explored as potential countermeasures for radiation hematopoietic injuries. We investigated cells cultured from amnion (Amnion-derived Multipotent Progenitor cells, AMPs) for effects on hematopoietic recovery following total body irradiation in mice.
C57BL/6J mice were sham-irradiated or exposed to 60Co irradiation (7.75 – 7.90 Gy, 0.6 Gy/min). Either AMPs (5 × 106 cells/animal) or vehicle were administered 24 h postirradiation via intraperitoneal injection. R
esults: We observed a 13% and 20% improvement in 30-day survival of mice treated with AMPs compared with treatment with vehicle following irradiation at 7.75 and 7.90 Gy, respectively. AMP treatment was characterized by a trend toward accelerated recovery of white blood cells, neutrophils, reticulocytes, and monocytes, measured through day 40 postirradiation after 7.75 Gy. AMP treatment enhanced hematopoietic cell repopulation of spleen and femoral bone marrow as measured by total nucleated cell and hematopoietic progenitor cell counts in comparison to vehicle-treated animals. FACS analysis showed that AMPs treatment significantly mitigated the reduction in CD11bﱪ1int and CD11bﱪ1high bone marrow cell populations at the nadir, and improved recovery of these cell types.
Together, our data indicate that AMPs reduced hematopoietic toxicity induced by ionizing radiation when infused within 24 h after radiation injury.

Multiple Sclerosis (MS) has been explained as an autoimmune mediated disorder in central nerve system. Since conventional therapies for MS are not able to stop or reverse the destruction of nerve tissue, stem cell-based therapy has been proposed for the treatment of MS. Astaxanthin (AST) is a red fat-soluble xanthophyll with neuroprotection activity. The aim of this study was evaluation of pre-inducer function of AST on differentiation of human Adipose- Derived Stem Cells (hADSCs) into oligodendrocyte precursor cells.
After stem cell isolation, culture and characterization by flow cytometry, hanging drop technique was done for embryoid body formation. In the following, hADSCs were differentiated into oligodendrocyte cells in the presence of AST at various concentrations (1, 5, and 10 ng/ml). Finally, immunocytochemistry and real-time PCR techniques were used for assessment of oligodendrocyte differentiation.
Flow cytometry results indicated that hADSCs were CD44, CD49-positive, but were negative for CD14, CD45 markers. In addition, immunocytochemistry results revealed that, in AST treated groups, the mean percentage of Olig 2 and A2B5 positive cells increased especially in 5 ng/ml AST treated group compared to control group (p Since hADSCs have the potential to differentiate into multi lineage cells and due to important functions of AST in regulating various cellular processes, it seems that AST can be used as a promoter for oligodendrocyte differentiation of hADSCs for being used in cell transplantation in multiple sclerosis.

Stem cell-based therapy is a new method for the treatment of neurodegenerative diseases such as multiple sclerosis (MS). Human adipose-derived stem cells (hADSCs) are a kind of adult stem cells which have a higher frequency in the fat tissue and have the ability to differentiate into other cell types outside their lineage. Due to some serious adverse events of cell-based therapy such as tumorigenic potential, the aim of this study was to evaluate of hADSCs differentiation into oligodendrocytes as a valuable way for future cell transplantation.

hADSC were isolated from lipoaspirate samples of human abdominal fat. After hADSC characterization via flow cytometry, the cells were induced to oligodendrocytes using a special differentiation medium. Finally, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), immunocytochemistry, and real-time polymerase chain reaction (RT-PCR) techniques were used for the evaluation of differentiated cells.

Flow cytometry indicated that hADSCs were CD105- and CD49-positive, but were negative for CD31 and CD45 markers. In addition, immunocytochemistry analysis revealed that a high percent of differentiated cells expressed oligodendrocyte progenitor cells markers [A2B5 and oligodendrocyte transcription factor (Olig2)] which were significantly higher than myelin basic protein (MBP) which is mature oligodendrocytes marker. Moreover, a very low percentage of differentiated cells expressed glial fibrillary acidic protein (GFAP) marker. Finally, real-time reverse transcription PCR analysis confirmed the results of immunocytochemistry.

Since hADSCs have the potential to differentiate into multi-lineage cells and due to their additional characteristics such as immunomodulatory and neuroprotective properties, it seems that these cells may be an ideal cell source for oligodendrocytes differentiation.

The presence of neurotrophic factors is critical for regeneration of neural lesions. Here, we transplanted combination of neurotrophic factor secreting cells (NTF-SCs) and human adipose derived stem cells (hADSCs) into a lysolecithin model of multiple sclerosis (MS) and determined the myelinization efficiency of these cells.
In this experimental study, 50 adult rats were randomly divided into five groups: control, lysolecithin, vehicle, hADSCs transplantation and NTF-SCs/ hADSCs co-transplantation group. Focal demyelization was induced by lysolecithin injection into the spinal cord. In order to assess motor functions, all rats were scored weekly with a standard experimental autoimmune encephalomyelitis scoring scale before and after cell transplantation. Four weeks after cell transplantation, the extent of demyelination and remyelination were examined with Luxol Fast Blue (LFB) staining. Also, immunofluorescence method was used for evaluation of oligodendrocyte differentiation markers including; myelin basic protein (MBP) and Olig2 in the lesion area.
Histological study show somewhat remyelinzation in cell transplantation groups related to others. In addition, the immunofluorescence results indicated that the MBP and Olig2 positive labeled cells were significantly higher in co-cell transplantation group than hADSCs group (P Our results indicated that the remyelinization process in co-cell transplantation group was better than other groups. Thus, NTF-SCs/ hADSCs transplantation can be proper candidate for cell based therapy in neurodegenerative diseases, such as MS.

Mesenchymal stem cells (MSC) can be isolated from adult tissues such as adipose tissue and other sources. Among these sources, adipose tissue (because of easy access) and placenta (due to its immunomodulatory properties, in addition to other useful properties), have attracted more attention in terms of research. The isolation and comparison of MSC from these two sources provides a proper source for clinical experimentation. The aim of this study was to compare the characteristics of MSC isolated from human adipose tissue and placenta. Adipose and placental MSC were isolated from the subcutaneous adipose tissues of 10 healthy women (25 to 40 years) and from a fresh term placenta (n= 1), respectively. Stem cells were characterized and compared by flow cytometry using CD29, CD31, CD34, CD44, CD45, CD105, CD166 and HLA-DR markers. Osteocytes and adipocytes were differentiated from isolated human mesenchymal stem cells (HMSC). Adipose and placenta-derived MSC exhibited the same morphological features. ADSC differentiated faster than placenta; however, both were differentiated, taking up to 21 days for osteocyte and 14 days for adipocyte differentiation. About 90% of PLC-MSC and ADSC were positive for CD29, CD44, CD105, and CD166; and negative for CD31, CD34, CD45, and HLA-DR. The two sources of stem cells showed similar surface markers, morphology and differentiation potential and because of their multipotency for differentiating to adipocytes and osteocytes, they can be applied as attractive sources of MSC for regenerative medicine.

Limited resources for adult stem cells necessitate their in vitro culture prior to clinical use. Investigating mitochondrial DNA (mtDNA) and telomere shortening has proved to be important indications of stem cell validity. This study was designed to investigate these indicators in multiple passages of three adult stem cell lines which were produced in our stem cell laboratory. In this study, Dental Pulp Stem Cells (DPSCs), Periapical Follicle Stem Cells (PAFSCs) and Human Foreskin Fibroblast (HFF) cell lines were expanded for 20 passages. After 1, 5, 10, 15 and 20 passages, expanded cells were harvested and DNA was extracted for further studies. Common mtDNA mutation was detected by multiplex PCR and telomere shortening was tested by Southern blot analysis. The common deletion was not detected in any of the stem cells or cell lines after several passages. In addition, Southern blot analysis indicated that the mean difference of telomere length between first and last passage was 0.25 kb in DPSC, 0.1 kb in PAFSC and 0.32 kb in HFF which indicates that the mean telomere length in various passages of the samples showed insignificant changes. Absence of mtDNA mutations in adult stem cell lines indicates good mitochondrial function even after 20 passages. In addition, absence of telomere shortening indicates stem cells validity after multiple passages. It is hoped this information could pave the way for using in vitro expansion of adult stem cells for future clinical applications.

Stem cell research has received considerable attention since the discovery that adult stem cells havethe capacity to form many different tissue types. Stem cells are a booming field for the researchand have been extensively studied in the field of medicine, as well as dentistry. Their applicationin oncology has been a boon to many of the patients. Dental stem cells have been novel approachto treat diseases like periodontitis, dental caries and many more. Their potential uses in dentistryhave provided a new generation of treatments for dental diseases and stem cells have become thefocus in dental research. This review highlights about the biology, sources and potential applicationsof stem cells in dentistry with emphasis on a dentist’s role in enabling both medical and dentalapplications using stem cells from teeth.