Objective To investigate the effect of simvastatin on inducing endothel ial progenitor cells (EPCs) homing and promoting bone defect repair, and to explore the mechanism of local implanting simvastatin in promoting bone formation. Methods Simvastatin (50 mg) compounded with polylactic acid (PLA, 200 mg) or only PLA (200 mg) was dissolved in acetone (1 mL) to prepare implanted materials (Simvastatin-PLA material, PLA material). EPCs were harvested from bone marrow of 2 male rabbits and cultured with M199; after identified by immunohistochemistry, the cell suspension of EPCs at the 3rd generation (2 × 106 cells/mL) was prepared and transplanted into 12 female rabbits through auricular veins(2 mL). After 3 days, the models of cranial defect with 15 cm diameter were made in the 12 female rabbits. And the defects were repaired with Simvastatin-PLA materials (experimental group, n=6) and PLA materials (control group, n=6), respectively. The bone repair was observed after 8 weeks of operation by gross appearance, X-ray film, and histology; gelatin-ink perfusion and HE staining were used to show the new vessels formation in the defect. Fluorescence in situ hybridization (FISH) was performed to show the EPCs homing at the defect site. Results All experimental animals of 2 groups survived to the end of the experiment. After 8 weeks in experimental group, new bone formation was observed in the bone defect by gross and histology, and an irregular, hyperdense shadow by X-ray film; no similar changes were observed in control group. FISH showed that the male EPC containing Y chromosome was found in the wall of new vessels in the defect of experimental group, while no male EPC containing Y chromosome was found in control group. The percentage of new bone formation in defect area was 91.63% ± 4.07% in experimental group and 59.45% ± 5.43% in control group, showing significant difference (P lt; 0.05). Conclusion Simvastatin can promote bone defect repair, and its mechanism is probably associated with inducing EPCs homing and enhancing vasculogenesis.
ObjectiveTo investigate the ability of autologous peripheral blood endothelial progenitor cells (EPCs) in promoting neovascularization of tissue engineered bone and osteogenesis of bone marrow mesenchymal stem cells (BMSCs). MethodThe peripheral blood EPCs and BMSCs from No. 1-9 New Zealand rabbits were isolated, cultured, and identified. According to the cell types, the third generation of cells were divided into 3 groups:EPCs (group A), BMSCs (group B), and co-cultured cells of EPCs and BMSCs (group C, EPCs:BMSCs=1:2) . Then cells were seeded on the partially deproteinised bone (PDPB) packaged with fibronectin to construct tissue engineered bone. After 4 days, autologous heterotopic transplantation of tissue engineered bone was performed in the rabbit's muscles bag of groups A, B, and C (the right arm, left arm, right lower limb respectively, 2 pieces each part). At 2, 4, and 8 weeks after transplantation, the growth of tissue engineered bone was observed, and the rate of bone ingrowth was calculated by HE staining; the expressions of CD34, CD105, and zonula occludens protein 1(ZO-1) were compared by immunohistochemical staining at each time point in tissue engineered bone among 3 groups. ResultsThe EPCs and BMSCs were isolated and identified successfully; immunofluorescent staining showed that EPCs were positive for CD34, CD133, and von Willebrand factor (vWF), and BMSCs were positive for CD29 and CD90 and were negative for CD34. The tissue engineered bone constructed in 3 groups was transplanted successfully. At 2, 4, and 8 weeks after autologous heterotopic transplantation, the general observations showed that the soft tissue around the tissue engineered bone increased and thickened gradually in each group with time passing; the boundary between bone and soft tissue was not clear; the pore space of tissue engineered bone gradually was filled, especially in group C, the circuitous vascular network could be seen in the tissue engineered bone. HE staining showed capillaries and collagen fibers increased gradually, tissue engineered bone ingrowth rate was significantly higher in group C than groups A and B at 4 and 8 weeks (P<0.05) , and group B was significantly higher than group A (P<0.05) . Immunohistochemical staining showed that the expressions of CD34, CD105, and ZO-1 in tissue engineered bone of 3 groups all increased with the extension of time, showing significant differences between groups at each time point (P<0.05) . At 2 weeks after transplantation, the expression of CD105 in group C was significantly higher than that in groups A and B (P<0.05) ; at 4 and 8 weeks, CD34, CD105, and ZO-1 expressions showed significant differences between 2 groups (P<0.05) ; the expression was the highest in group C, and was the lowest in group B. ConclusionsAutologous peripheral blood EPCs and BMSCs have synergistic effect, and can promote neovascularization and osteogenesis of tissue engineered bone in vivo.
ObjectiveTo review the current progresses in purification strategies, biological characters, and functions of endothelial progenitor cells (EPCs) derived extracellular vesicles (EVs) (EPC-EVs). MethodsRecent relevant publications on the EPC-EVs were extensively reviewed, analyzed, and summarized. ResultsEPC-EVs are usually isolated by differential centrifugation and exhibit a homogenous pattern of spheroid particles with a diameter ranging from 60 to 160 nm under transmission electron microscopy. EPC-EVs are positive for cell-surface markers of EPCs (CD31, CD34, and CD133), and negative for markers of platelets (P-selectin and CD42b) and monocytes (CD14). Recent studies have shown the effectiveness of EPC-EVs in ischemic injuries, anti-Thy1 glomerulonephritis, and cardiomyocyte hypertrophy, and also shown their predictive role in cardio-cerebral-vascular diseases. ConclusionAn alluring prospect exists on the EPC-EVs-related research. Further studies are required to decipher the composition of EPC-EVs and their precise role in pathophysiological processes, and to investigate the molecular mechanisms for their targeting and function.
Objective To examine the effect of endothelial progenitor cell (EPC) on lung ischemia-reperfusion injury (LIRI). Methods Twenty-four recipients were randomized into 3 groups including a sham group, a LIRI group, and an EPC group. Rats in the sham group only received anesthesia. Rats in the LIRI and EPC groups received left lung transplantation and received saline or EPC immediately after reperfusion. The partial pressure of oxygen to fraction of inspiratory oxygen (PaO2/FiO2) ratio, wet-to-dry weight ratio and protein levels in the transplanted lung and inflammation-related factors levels in serum were examined. Histological change of transplanted lung were analyzed. The nuclear factor (NF)-κB in the transplanted lung was detected. Results Compared with the LIRI group, the PaO2/FiO2 ratio dramaticly increased, and the wet-to-dry weight ratio and protein level significantly decreased by EPC after reperfusion. The lung histological injury was attenuated by EPC. The pro-inflammatory factors in serum were down-regulated, whereas IL-10 was up-regulated in the EPC group. The expression of NF-κB was decreased by EPC. Conclusion EPC ameliorated LIRI after lung transplantation. The protection of EPC partly associated with anti-inflammation.
Objective To observe endothelial progenitor cells (EPCs) participating in the formation of neovascularization in lung adenocarcinoma. Methods EPCs were transfected by recombinant adenovirus carrying LacZ gene in optimal transfection concentration, and then EPCs were injected into animal models of lung adenocarcinoma through the tail vein; afterwards, lung tissues were taken out for pathological examination in the 6th, 7th, 8th week respectively. EPCs were observed to take part in the angiogenesis in the lung adenocarcinoma through X-gal chromogenic dye. Results The optimal multiplicity of infection (MOI) of AD5F35LacZ transfected EPCs was 400. When MOI was 400, maximum transfection efficiency was 97.13±2.08. After 2 weeks, LacZ gene-transfected EPCs began to proliferate in vitro culture, then the EPCs were transplanted into animal models of lung cancer to be involved in the neovascularization formation in the 8th week after transplantation. Conclusion EPCs are involved in the formation of tumor neovascularization after transplantation.
ObjectiveTo review the research progress of the co-culture system for constructing vascularized tissue engineered bone. MethodsThe recent literature concerning the co-culture system for constructing vascularized tissue engineered bone was reviewed, including the selection of osteogenic and endothelial lineages, the design and surface modification of scaffolds, the models and dimensions of the co-culture system, the mechanism, the culture conditions, and their application progress. ResultsThe construction of vascularized tissue engineered bone is the prerequisite for their survival and further clinical application in vivo. Mesenchymal stem cells (owning the excellent osteogenic potential) and endothelial progenitor cells (capable of directional differentiation into endothelial cell) are considered as attractive cell types for the co-culture system to construct vascularized tissue engineered bone. The culture conditions need to be further optimized. Furthermore, how to achieve the clinical goals of minimal invasion and autologous transplantation also need to be further studied. ConclusionThe strategy of the co-culture system for constructing vascularized tissue engineered bone would have a very broad prospects for clinical application in future.
Objective To investigate the effects of titanium modified by ultrasonic acid etching/anodic oxidation (UAT) loaded with endothelial progenitor cells-exosome (EPCs-exo) on proliferation and osteogenic and angiogenic differentiations of adipose-derived stem cells (ADSCs). Methods The adipose tissue and bone marrow of 10 Sprague Dawley rats were harvested. Then the ADSCs and EPCs were isolated and cultured by collagenase digestion method and density gradient centrifugation method, respectively, and identified by flow cytometry. Exo was extracted from the 3rd to 5th generation EPCs using extraction kit, and CD9 and CD81 were detected by Western blot for identification. The three-dimensional printed titanium was modified by ultrasonic acid etching and anodic oxidation to prepare the UAT. The surface characteristics of UAT before and after modification was observed by scanning electron microscopy; UAT was placed in EPCs-exo solutions of different concentrations (100, 200 ng/mL), and the in vitro absorption and release capacity of EPCs-exo was detected by BCA method. Then, UAT was placed in DMEM medium containing different concentrations of EPCs-exo (0, 100, 200 ng/mL), and co-cultured with the 3rd generation ADSCs to construct UAT-ADSCs-exo. Cell morphology by laser confocal microscopy, live/dead cell staining, and cell proliferation were observed to evaluate biocompatibility; alkaline phosphatase (ALP) staining and alizarin red staining, RT-PCR detection of osteogenesis-related genes [osteocalcin (OCN), RUNT-related transcription factor 2 (Runx2), ALP, collagen type 1 (COL-1)] and angiogenesis-related gene [vascular endothelial growth factor (VEGF)], immunofluorescence staining for osteogenesis (OCN)- and angiogenesis (VEGF)-related protein expression were detected to evaluate the effect on the osteogenic and angiogenic differentiation ability of ADSCs. Results Scanning electron microscopy showed that micro-nano multilevel composite structures were formed on the surface of UAT. About 77% EPCs-exo was absorbed by UAT within 48 hours, while EPCs-exo absorbed on the surface of UAT showed continuous and stable release within 8 days. The absorption and release amount of 200 ng/mL group were significantly higher than those of 100 ng/mL group (P<0.05). Biocompatibility test showed that the cells in all concentration groups grew well after culture, and the 200 ng/mL group was better than the other groups, with fully spread cells and abundant pseudopodia, and the cell count and cell activity were significantly higher than those in the other groups (P<0.05). Compared with the other groups, 200 ng/mL group showed enhanced ALP activity and mineralization ability, increased expressions of osteogenic and angiogenic genes (OCN, Runx2, COL-1, ALP, and VEGF), as well as increased expressions of OCN and VEGF proteins, with significant differences (P<0.05). Conclusion EPCs-exo can effectively promote the adhesion, proliferation, and osteogenic and angiogenic differentiation of ADSCs on UAT surface, the effect is the most significant when the concentration is 200 ng/mL.
ObjectiveTo separate peripheral blood mesenchymal stem cells (PBMSC) and peripheral blood endothelial progenitor cells (PBEPC) from peripheral blood, and investigate the biological characteristics of composite cell sheets of PBMSC and PBEPC.MethodsThe peripheral blood of healthy adult New Zealand white rabbits was extracted and PBMSC and PBEPC were separated by density gradient centrifugation. Morphological observation and identification of PBMSC and PBEPC were performed. The 3rd generation of PBMSC and PBEPC were used to construct a composite cell sheet at a ratio of 1∶1, and the 3rd generation of PBMSC was used to construct a single cell sheet as control. The distributions of cells in two kinds of cell sheets were observed by HE staining. In addition, the expression of alkaline phosphatase (ALP), osteocalcin (OCN), and vascular endothelial growth factor (VEGF) in the supernatants of cell sheets were observed by ELISA at 1, 5, and 10 days after osteogenic induction.ResultsThe morphology of PBMSC was spindle-shaped or polygonal, and PBMSC had good abilities of osteogenic and adipogenic differentiation. The morphology of PBEPC was paved stone-like, and the tube-forming test of PBEPC was positive. Two kinds of cell sheets were white translucent. The results of HE staining showed that the composite cell sheet had more cell layers and higher cell density than the single cell sheet. The expressions of ALP, OCN, and VEGF in the supernatant of the two groups of cell sheets increased with the time of induction. The expression of OCN in the group of composite cell sheet was significantly higher than that in the group of single cell sheet on the 5th and 10th day, ALP on the 10th day was significantly higher than that in the group of single cell sheet, VEGF expression on the 1st, 5th, and 10th day was significantly higher than that in the group of single cell sheet, all showing significant differences (P<0.05), and there was no significant difference between the two groups at other time points (P>0.05).ConclusionPBMSC have stable differentiation ability, and they have good application prospects because of their minimally invasive access. Composite cell membranes constructed by co-culture of two kinds of cells and induction of membrane formation provides a new idea and exploration for tissue defect repair.
Objective To observe the effects of Galectin-3 on proliferation of vascular endothelial cells derived from peripheral blood endothelial progenitor cells. Methods The cultured peripheral blood endothelial progenitor cells in vitro were isolated and purified from human peripheral blood, and the cells were differentiated into vascular endothelial cells. Then the cells were cultivated with the galectin-3 of different concentrations, and to observe the proliferation of endothelial cells derived from peripheral blood endothelial progenitor cells. Results The abilities of proliferation of endothelial cells derived from peripheral blood endothelial progenitor cells of 0.1, 1.0, 2.5, 5.0, and 10.0 μg/ml groups were higher than that of 0 μg/ml group, there were not statistic significance of the differences between the 0.1，1.0, 2.5, and 0 μg/ml groups （P＞0.05）. But the abilities of proliferation of 5.0 and 10.0 μg/ml groups were obviously higher than that of 0, 0.1, 1.0, and 2.5 μg/ml groups （P＜0.05）, and the abilities of proliferation of 10.0 μg/ml group was also higher than that of 5.0 μg/ml group （P＜0.05）. Conclusion Galectin-3 can promote the proliferation of endothelial cells derived from peripheral blood endothelial progenitor cell.
Objective To evaluate effect of hypoxia condition (1% or 5% oxygen concentration) on proliferation, adhesion, migration, or viability ability of bone morrow-derived endothelial progenitor cells (EPCs). Methods The bone marrow mononuclear cells of SD rat were acquired with density gradient centrifugation method. They were cultured, induced, and differentiated to the EPCs. Then they were cultured respectively in three different oxygen concentrations (1%, 5%, or 21%). On the 3rd day and the 7th day, the effects of the different oxygen concentrations (1%, 5%, or 21%) on the EPCs’ neovascularization characteristics (including proliferation, adhesion, migration, and viability abilities) were evaluated. Results Whether cultured for the 3rd day or 7th day, the proliferation, adhesion, migration, and viability abilities of the cultured cells in the 1% and 5% oxygen concentrations were significantly better than those of the cultured cells in the 21% oxygen concentration (all P<0.05). Except for the proliferation ability of the cultured cells in the 5% oxygen concentration was significantly better than that of the cultured cells in the 1% oxygen concentration (P<0.05) on the 3rd day, and the adhesion ability on the 3rd day and the proliferation ability on the 7th day had no significantly differences, the other abilities (adhesion, migration, and viability abilities) of the cultured cells in the 1% oxygen concentration were significantly better than those of the cultured cells in the 5% oxygen concentration (allP<0.05). Conclusion Different oxygen concentration has an effect on proliferation, adhesion, migration, or viability ability of bone morrow-derived EPCs, appropriate hypoxia condition (1% or 5% oxygen concentration ) can enhance these abilities.