ABSTRACT
Osteoporosis is a metabolic bone disease characterized by decreased bone mass and degenerative changes in the microstructure of bone tissue,leading to increased bone brittleness and fracture risk.Bone fracture after osteoporosis is the most common and serious complication,which often leads to serious consequences in cases of inadequate prevention and late diagnosis.Therefore,more attention should be paid to prevention of osteoporosis and risk assessment of fracture and refracture after osteoporosis.This paper reviews the research progress in risk assessment of fracture and refracture after osteoporosis from the aspects of imaging,clinical manifestations and laboratory examination indexes.In recent years,the imaging methods have developed from dual-energy X-ray absorption,trabecular bone scoring and CT to high resolution peripheral quantitative CT;concern for their clinical manifestations has developed from independent risk factors to fracture risk assessment tools;the laboratory tests have developed from bone turnover markers and serotonin to microRNA.Although these developments have consistently increased the sensitivity of risk assessment for fracture and refracture after osteoporosis,problems still exist and need to be resolved.
ABSTRACT
Osteoporosis is a metabolic bone disease characterized by decreased bone mass and degenerative changes in the microstructure of bone tissue, leading to increased bone brittleness and fracture risk. Bone fracture after osteoporosis is the most common and serious complication, which often leads to serious consequences in cases of inadequate prevention and late diagnosis. Therefore, more attention should be paid to prevention of osteoporosis and risk assessment of fracture and refracture after osteoporosis. This paper reviews the research progress in risk assessment of fracture and refracture after osteoporosis from the aspects of imaging, clinical manifestations and laboratory examination indexes. In recent years, the imaging methods have developed from dual-energy X-ray absorption, trabecular bone scoring and CT to high resolution peripheral quantitative CT; concern for their clinical manifestations has developed from independent risk factors to fracture risk assessment tools; the laboratory tests have developed from bone turnover markers and serotonin to microRNA. Although these developments have consistently increased the sensitivity of risk assessment for fracture and refracture after osteoporosis, problems still exist and need to be resolved.
ABSTRACT
Osteoarthritis is a common cause of functional deterioration in older adults and is an immense burden on the aging population. Altered chondrogenesis is the most important pathophysiological process involved in the development of osteoarthritis. However, the molecular mechanism underlying the regulation of chondrogenesis in patients with osteoarthritis requires further elucidation, particularly with respect to the role of microRNAs. MiR-21 expression in cartilage specimens was examined in 10 patients with knee osteoarthritis and 10 traumatic amputees. The effect of miR-21 on chondrogenesis was also investigated in a chondrocyte cell line. The effect of miR-21 on the expression of growth differentiation factor 5 (GDF-5) was further assessed by luciferase reporter assay and western blot. We found that endogenous miR-21 is upregulated in osteoarthritis patients, and overexpression of miR-21 could attenuate the process of chondrogenesis. Furthermore, we identified GDF-5 as the direct target of miR-21 during the regulation of chondrogenesis. Our data suggest that miR-21 has an important role in the pathogenesis of osteoarthritis and is a potential therapeutic target.
Subject(s)
Humans , Cartilage/metabolism , Case-Control Studies , Cell Line , Chondrocytes/metabolism , Growth Differentiation Factor 5/genetics , MicroRNAs/genetics , Osteoarthritis/metabolism , Up-RegulationABSTRACT
To study the cartilage differentiation of mouse mesenchymal stem cells (MSCs) induced by cartilage-derived morphogenetic proteins-2 in vitro, the MSCs were isolated from mouse bone marrow and cultured in vitro. The cells in passage 3 were induced into chondrogenic differentiation with different concentrations of recombinant human cartilage-derived morphogenetic proteins-2 (0,10, 20, 50 and 100 ng/mL). After 14 days of induction, morphology of cells was observed under phase-contrast microscope. Collagen Ⅱ mRNA and protein were examined with RT-PCR, Western blotting and immunocytochemistry respectively and the sulfate glycosaminoglycan was measured by Alcian blue staining. RT-PCR showed that CDMP-2 could promote expression of collagen Ⅱ mRNA in an dose-dependant manner, especially at the concentration of 50 ng/mL and 100 ng/mL.Immunocytochemistry and Western blotting revealed a similar change. Alcian blue staining exhibited deposition of typical cartilage extracellular matrix. Our results suggest that mouse bone marrow mesencymal stem cells can differentiate into chondrogenic phonotype with the induction of CDMP-2 in vitro, which provides a basis for further research on the role of CDMP-2 in chondrogenesis.
ABSTRACT
By preventing mesenchymal stem cells (MSCs) from adhering to precoated agarose to create a model of MSC suspension in vitro, we investigated anoikis in MSCs and the role of caspase-3 in the anoikis. The cultured MSCs were randomly divided into 3 groups: the anoikis group,caspase-3 inhibitor group and control group. Before experiment, we coated dishes with 1.5 % agarose;in the anoikis group, MSCs were put into the precoated dishes; and in the inhibitor group, caspase-3 inhibitor and MSCs were also put into the precoated dishes; but there were not intervention in the control group. MSCs were collected at 2 h, 6 h, 12 h and 24 h. The alteration of caspase-3 activity was evaluated by caspase-3 fluorometric assay and western blot analysis. The apoptosis rates were detected by flow cytometry. MSCs were round and suspended sufficiently in the anoikis and inhibitor groups. Caspase-3 fluorometric assay showed that there were significant differences in statistics between the anoikis group and the others (P＜0.05). Western blot analysis discovered that caspase-3 expression.in the anoikis group was more than that in the control and inhibitor groups (P＜0.05). Flow cytometry showed that the apoptosis peak appeared in all the three groups, but it increased dramatically in the anoikis group. The apoptosis rates in the inhibitor and control groups were low and stable.And there were significant differences in statistics between the anoikis group and the others (P＜0.05).MSCs will undergo anoikis in suspended condition if they are separated from the extracellular matrix.Caspase-3 inhibitors can suppress caspase-3 activity and reduce the apoptosis rate significantly. Caspase-3 plays a vital part in induced MSC anoikis in vitro. MSCs suspension culture system might be set up with argorose and caspase-3 inhibitor.
ABSTRACT
To study the cartilage differentiation of mouse mesenchymal stem cells (MSCs) induced by cartilage-derived morphogenetic proteins-2 in vitro, the MSCs were isolated from mouse bone marrow and cultured in vitro. The cells in passage 3 were induced into chondrogenic differentiation with different concentrations of recombinant human cartilage-derived morphogenetic proteins-2 (0, 10, 20, 50 and 100 ng/mL). After 14 days of induction, morphology of cells was observed under phase-contrast microscope. Collagen II mRNA and protein were examined with RT-PCR, Western blotting and immunocytochemistry respectively and the sulfate glycosaminoglycan was measured by Alcian blue staining. RT-PCR showed that CDMP-2 could promote expression of collagen II mRNA in an dose-dependant manner, especially at the concentration of 50 ng/mL and 100 ng/mL. Immunocytochemistry and Western blotting revealed a similar change. Alcian blue staining exhibited deposition of typical cartilage extracellular matrix. Our results suggest that mouse bone marrow mesenchymal stem cells can differentiate into chondrogenic phonotype with the induction of CDMP-2 in vitro, which provides a basis for further research on the role of CDMP-2 in chondrogenesis.
Subject(s)
Bone Marrow Cells/cytology , Bone Morphogenetic Proteins/pharmacology , Cell Differentiation/drug effects , Cells, Cultured , Chondrocytes/cytology , Chondrogenesis/drug effects , Chondrogenesis/physiology , Mesenchymal Stem Cells/cytology , Recombinant Proteins/pharmacologyABSTRACT
By preventing mesenchymal stem cells (MSCs) from adhering to precoated agarose to create a model of MSC suspension in vitro, we investigated anoikis in MSCs and the role of caspase-3 in the anoikis. The cultured MSCs were randomly divided into 3 groups: the anoikis group, caspase-3 inhibitor group and control group. Before experiment, we coated dishes with 1.5 % agarose; in the anoikis group, MSCs were put into the precoated dishes; and in the inhibitor group, caspase-3 inhibitor and MSCs were also put into the precoated dishes; but there were not intervention in the control group. MSCs were collected at 2 h, 6 h, 12 h and 24 h. The alteration of caspase-3 activity was evaluated by caspase-3 fluorometric assay and western blot analysis. The apoptosis rates were detected by flow cytometry. MSCs were round and suspended sufficiently in the anoikis and inhibitor groups. Caspase-3 fluorometric assay showed that there were significant differences in statistics between the anoikis group and the others (P<0.05). Western blot analysis discovered that caspase-3 expression in the anoikis group was more than that in the control and inhibitor groups (P<0.05). Flow cytometry showed that the apoptosis peak appeared in all the three groups, but it increased dramatically in the anoikis group. The apoptosis rates in the inhibitor and control groups were low and stable. And there were significant differences in statistics between the anoikis group and the others (P<0.05). MSCs will undergo anoikis in suspended condition if they are separated from the extracellular matrix. Caspase-3 inhibitors can suppress caspase-3 activity and reduce the apoptosis rate significantly. Caspase-3 plays a vital part in induced MSC anoikis in vitro. MSCs suspension culture system might be set up with argorose and caspase-3 inhibitor.