189 research outputs found
Evaluation and comparison of the in vitro characteristics and chondrogenic capacity of four adult stem/progenitor cells for cartilage cell-based repair
No full textCell-based therapy is being considered as a promising approach to regenerate damaged cartilage. Though, autologous chondrocyte implantation is the most effective strategy currently in use, but is hampered by some drawbacks seeking comprehensive research to surmount existing limitations or introducing alternative cell sources. In this study, we aimed to evaluate and compare the in vitro characteristics and chondrogenic capacity of some easily available adult cell sources for use in cartilage repair which includes: bone marrow-derived mesenchymal stem cells (MSC), adipose tissue-derived MSC, articular chondrocyte progenitors, and nasal septum-derived progenitors. Human stem/progenitor cells were isolated and expanded. Cell's immunophenotype, biosafety, and cell cycle status were evaluated. Also, cells were seeded onto aligned electrospun poly (l-lactic acid)/poly (ε-caprolactone) nanofibrous scaffolds and their proliferation rate as well as chondrogenic potential were assessed. Cells were almost phenotypically alike as they showed similar cell surface marker expression pattern. The aligned nanofibrous hybrid scaffolds could support the proliferation and chondrogenic differentiation of all cell types. However, nasal cartilage progenitors showed a higher proliferation potential and a higher chondrogenic capacity. Though, mostly similar in the majority of the studied features, nasal septum progenitors demonstrated a higher chondrogenic potential that in combination with their higher proliferation rate and easier access to the source tissue, introduces it as a promising cell source for cartilage tissue engineering and regenerative medicine
A comparison between osteogenic differentiation of human unrestricted somatic stem cells and mesenchymal stem cells from bone marrow and adipose tissue
No full textTo evaluate the potential of three stem cells for cell therapy and tissue engineering applications, the biological behavior and osteogenic capacity of the newly introduced cord-blood-derived, unrestricted somatic stem cells (USSC) were compared with those of mesenchymal stem cells isolated from bone marrow (BM-MSC) and adipose tissue (AT-MSC). There was no significant difference between the rates of proliferation of the three stem cells. During osteogenic differentiation, alkaline phosphatase (ALP) activity peaked on day 7 in USSC compared to BM-MSC which showed the maximum value of ALP activity on day 14. However, BM-MSC had the highest ALP activity and mineralization during osteogenic induction. In addition, AT-MSC showed the lowest capacity for mineralization during differentiation and had the lowest ALP activity on days 7 and 14. Although AT-MSC expressed higher levels of collagen type I, osteonectin and BMP-2 in undifferentiated state, but these genes were expressed higher in BM-MSC during differentiation. BM-MSC also expressed higher levels of ALP, osteocalcin and Runx2 during induction. Taking together, BM-MSC showed the highest capacity for osteogenic differentiation and hold promising potential for bone tissue engineering and cell therapy applications
A collagen–poly(vinyl alcohol) nanofiber scaffold for cartilage repair
No full textArticular cartilage has a limited capacity for self-repair. Untreated injuries of cartilage may lead to osteoarthritis. This problem demands new effective methods to reconstruct articular cartilage. Mesenchymal stem cells (MSCs) have the proclivity to differentiate along multiple lineages giving rise to new bone, cartilage, muscle, or fat. This study was an animal model for autologous effects of transplantation of MSCs with a collagen–poly(vinyl alcohol) (PVA) scaffold into full-thickness osteochondral defects of the stifle joint in the rabbit as an animal model. A group of 10 rabbits had a defect created experimentally in the full thickness of articular cartilage penetrated into the subchondral space in the both stifle joints. The defect in the right stifle was filled with MSCs/collagen–PVA scaffold (group I), and in the left stifle, the defect was left without any treatment as the control group (group II). Specimens were harvested at 12 weeks after implantation, examined histologically for morphologic features, and stained immunohistochemically for type-II collagen. Histology observation showed that the MSCs/collagen–PVA repair group had better chondrocyte morphology, continuous subchondral bone, and much thicker newly formed cartilage compared with the control group at 12 weeks post operation. There was a significant difference in histological grading score between these two groups. The present study suggested that the hybrid collagen–PVA scaffold might serve as a new way to keep the differentiation of MSCs for enhancing cartilage repair
Stability and Stabilization of the Wave Model.
No full textThe stability properties of 2-D systems are an important aspect of the design of acoustic, seismic, image and sonar signal processors. This research utilizes the Wave model format to transport 1-D stability techniques to the 2-D setting. The research studies stability through multistep growth bounds on the Wave state. The use of Lyapunov theory is also considered. The research considers also the problem of stabilizing a 2-D system using state and/or output information feedback to interior and/or boundary controls. Finally the problem of observer design for 2-D systems is considered, with the new stability criteria being used to assure observer/system convergence. New results based on symmetrizability are also discussed. The principal results are illustrated by a number of examples. The results are also interpreted in the context of other contemporary local state models
Comparative immunomodulatory properties of adipose-derived mesenchymal stem cells conditioned media from BALB/c, C57BL/6, and DBA mouse strains
No full textAdipose tissue-derived mesenchymal stem cells (AD-MSCs) have been shown to be capable of differentiating into multiple cell type and exert immunomodulatory effects. Since the selection of ideal stem cell is apparently crucial for the outcome of experimental stem cell therapies, therefore, in this study we compared AD-MSCs conditioned media (CM) from BALB/c, C57BL/6, and DBA mouse strains. No significant difference was found in the morphology, cell surface markers, in vitro differentiation and proliferation potentials of AD-MSCs isolated from C57BL/6, BALB/c, and DBA mice. The immunological assays showed some variation among the strains in the cytokines, nitric oxide (NO), and indoleamine 2,3-dioxygenase (IDO) production and immunomodulatory effects on splenocytes functions. Our results indicated a suppression of splenocytes proliferation in the presence of AD-MSC CM from the three inbred mouse strains. However, BALB/c CM exerted a higher suppression of splenocytes proliferation. AD-MSCs isolated from C57BL/6 and BALB/c mice produced higher levels of TGF-β than those from DBA mice. Furthermore, IL-17 and IDO production was higher in AD-MSCs isolated from BALB/c mice. Our results indicated an increased production of TGF-β, IL-4, IL-10, NO, and IDO by splenocytes in response to CM from BALB/c AD-MSCs. In conclusion, our results showed that the immunomodulatory properties of mouse AD-MSCs is strain-dependent and this variation should be considered during selection of appropriate stem cell source for in vivo experiments and stem cell therapy strategies
Enhanced chondrogenesis of human nasal septum derived progenitors on nanofibrous scaffolds
No full textTopographical cues can be exploited to regulate stem cell attachment, proliferation, differentiation and function\ud
in vitro and in vivo. In this study, we aimed to investigate the influence of different nanofibrous topographies on the chondrogenic differentiation potential of nasal septum derived progenitors (NSP) in vitro. Aligned and randomly oriented Ploy (L-lactide) (PLLA)/Polycaprolactone (PCL) hybrid scaffolds were fabricated via electrospinning. First, scaffolds were fully characterized, and then NSP were seeded on them to study their capacity to support stem cell attachment, proliferation and chondrogenic differentiation. Compared to randomly oriented nanofibers, aligned scaffolds showed a high degree of nanofiber alignment with much better tensile strength properties. Both scaffolds supported NSP adhesion, proliferation and chondrogenic differentiation.\ud
Despite the higher rate of cell proliferation on random scaffolds, a better chondrogenic differentiation was\ud
observed on aligned nanofibers as deduced from higher expression of chondrogenic markers such as collagen type II and aggrecan on aligned scaffolds. These findings demonstrate that electrospun constructs maintain NSP proliferation and differentiation, and that the aligned nanofibrous scaffolds can significantly enhance chondrogenic differentiation of nasal septum derived progenitor
In vitro immunomodulatory properties of osteogenic and adipogenic differentiated mesenchymal stem cells isolated from three inbred mouse strains
No full textMesenchymal stem cells (MSCs) are used for cell-based therapies because of their immunomodulatory properties. The immunomodulatory properties of adipogenic (AD) and osteogenic (OS) differentiated adipose tissue-derived MSCs (AD-MSCs) isolated from BALB/c, C57BL/6, and DBA mice were compared. Splenocytes proliferation was suppressed in the presence of AD-MSCs conditioned media in all mice. After OS differentiation, BALB/c AD-MSCs produced higher levels of TGF-β and IL-17 and lower levels of NO than AD-MSCs isolated from C57BL/6 and DBA mice. In addition, OS differentiated AD-MSCs isolated from DBA mice produced lower levels of IL-10 than AD-MSCs isolated from C57BL/6 and DBA mice. After in vitro AD and OD differentiation, AD-MSCs isolated from each mouse produced higher levels of NO and IDO than undifferentiated cells. Additionally, AD-MSCs isolated from C57BL/6 and DBA mice produced higher levels of NO than AD-MSCs isolated from BALB/c mice. Adipose tissue-derived MSCs thus retain their immunomodulatory properties after in vitro OS and AD differentiation in a strain-dependent manner
Comparison of acellular and cellular bioactivity of poly 3-hydroxybutyrate/hydroxyapatite nanocomposite and poly 3-hydroxybutyrate scaffolds
No full textNanocomposites have recently been identified as a useful scaffolding material in tissue engineering applications. Poly (3-hydroxybutyrate)/hydroxyapatite nanoparticles (P3HB)/(nHA) porous scaffolds were successfully fabricated through a solvent casting and particulate leaching technique. P3HB/nHA and P3HB scaffolds were prepared by the same technique for comparison. The structure of the nanocomposite and P3HB scaffolds was observed by SEM. The Energy Disperssive X-ray Analysis (EDXA, map of Ca) results indicated that HA nanoparticles were homogeneously dispersed in the P3HB matrix. X-ray diffraction (XRD) analysis showed that P3HB and HA coexist in the nanocomposite. Transmission electron microscopy (TEM) images also showed that the particle size of HA was 30 ∼ 40 nm. The porosity of the scaffolds was 84%, and macropores and micropores coexisted and interconnected throughout the scaffolds. Acellular bioactivity experiments showed that more HA crystals formed on the surface of the nanocomposite scaffold than on the P3HB scaffold after 4 weeks immersion in Simulated Body Fluid (SBF). Cell culture experiments demonstrated that the P3HB/nHA nanocomposite scaffold had a better tendency of proliferation and Alkaline Phosphatase (ALP) activity to MG 63 cells than the pure P3HB scaffold. It was found that nHA addition can improve acellular and cellular bioactivity of the P3HB scaffold
miRNAs expressed differently in cancer stem cells and cancer cells of human gastric cancer cell line MKN-45
No full textRecent studies show that cancers may originate from special cells named cancer stem cells (CSCs). As miRNAs have a prominent role in regulating cell activities, a question arise, that is, if there is any difference in miRNA expression level between CSC and other cancer cells of human gastric cancer cell line MKN-45. In this study, CSCs were isolated by fluorescence-activated cell sorter based on the expression level of cell surface marker CD44. CSC characteristics were checked using spheroid formation assay and soft agar assay. Using reverse transcriptase polymerase chain reaction (RT-PCR), the expression level of some stemness genes was studied. Real-time q-PCR was used for analysis of the expression level of miRNAs. CSCs were able to make spheroids and colonies, whereas other cancer cells failed to show aforementioned features. In addition, RT-PCR resulted in a difference in the expression levels of Nanog, Sox2, Lin28 and Oct-4 between these two kinds of cells. Real-time RT-PCR analysis demonstrated an increase in mir-21 and mir-302 expression level in CSCs, relative to cancer cells, whereas let-7a expression level was decreased in CSC in comparison with cancer cells, which may be due to their different differentiation level. On the other hand, mir-372, mir-373 and mir-520c-5p were markedly increased in cancer cells in comparison with CSCs. This study shows that there is a difference in miRNA expression level between CSCs and other cancer cells, which reflects dissimilar molecular pathways in these cells. These miRNAs may be promising objects for targeting CSCs specifically and efficiently
Super Twisting Sliding Mode Control for LTI Descriptor System Based on Disturbance Observer
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