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.
Objective To study the short and medium term effect of myocardial contractile force by implantation of endothelial progenitor cells （EPCs） in the myocardial infarction model. Methods Hundred and twenty SD rats were equally and randomly divided into experimental group and control group （60 rats in each group）. Acute myocardial infarction model was created by ligation of LAD. Autologous EPCs were purified from peripheral blood then implanted into the acute myocardial infarct site via topical injection. IMDM were used in control group. Specimens and muscle strip were harvested at 3, 6 weeks, 6, 8 and 12 months after EPCs implantation for contractile force study and to detect the expression of vascular endothelial growth factor（VEGF）, basic fibroblast growth factor （bFGF） and Ⅷ factor by immunohistology and video image digital analysis system. Results The expression of VEGF, bFGF and the microvessel counts in experimental group were much higher than those of control group（P〈 0.01） at 3, 6 weeks and 6 months after transplantation. The contractile force in experimental group was better than that in control group（P〈0.01） at the same time. But from 8 months after implantation, the contractile force and so on were not up in the experimental group. Conclusion EPCs, after being implanted into infarct myocardium, shows the ability of improvement of the contractile performance in infarcted myocardium by means of angiogenesis and vasculogenesis and the medium term results are persistent.
ObjectiveTo explore optimal conditions of isolation, culture and labeled with superparamagnetic iron oxide (SPIO) in vitro of rat bone marrow endothelial progenitor cells, and lay the foundations for the further EPCs tracer study in vivo. MethodsThe EPCs derived from rat bone marrow were isolated and cultured by using density gradient centrifugation, which were labeled with different concentrations SPIO, Prussian blue staining was used to detect the cells labeling rate, MTT assay was used to detect the cells proliferation activity, and Trypan blue staining was used to detect the cells vitality. ResultsEPCs gradually growed in monolayer arrangement about 7 d after cultured. When the concentration of SPIO was 50μg/mL, the highest labeling rate of Prussian blue staining was 90%, the growth state of labeled EPCs were good, and could normal adherent growth and passage. At this time, the cell viability and proliferation activity were the highest through trypan blue staining and MTT assay. ConclusionsEPCs can be labeled with SPIO easily and efficiently when the concentration was 50μg/mL?without interference on the viability and proliferation activity, which lay the foundations for the further EPCs tracer study in vivo.
ObjectiveTo research the magnetic labeled endothelial progenitor cells(EPCs) transplanted into the rat of venous thrombosis model through the tail vein and track transplanted stem cells in vivo, provide an effective monitoring technology for promoting organization and recanalization of deep venous thrombosis. MethodsBone marrowderived EPCs were extracted, purified, and identified, then labeled with the new SPIO particles. At the same time, the inferior vena cava thrombus models in rats were made, which were randomly divided into four groups:SPIO group (EPCs labeled with SPIO transplantation), Dil group (EPCs labeled with Dil transplantation), control group (simple EPCs transplantation), and blank control group (1 mL medium transplantation). After transplantation, the MRI, HE staining, and immunohistochemical staining were performed and the capillary density was counted under high-power microscope. ResultsThe MRI showed that EPCs labeled with SPIO had migrated to the inferior vena cava thrombus and the mass of high signal shade was seen, with the extension of time, the signal strengthened gradually. On day 14-21, the signal became the strongest, then decreased gradually. The immunohistochemical staining and HE staining showed that there were a mass of the new capillary in the specimens of thrombus of the SPIO group, Dil group, and control group, the difference was not statistically significant among these three groups(P > 0.05), but which was significant difference as compared with blank control group (P < 0.05). ConclusionCompared with EPCs labeled with Dil, it
Objective To determine the transfection efficiency of recombinant adenovirus to endothelial progenitor cells(EPCs) and provide the base of lung cancer therapy by transfecting human herpes simplex virusthymidine kinase（HSV-TK） gene to EPCs. Methods Admove recombinant adenovirus 5F35(AD5F35) which transfected with βgalactosidase(AD5F35LacZ) to the 24 well plate cultivated with EPCs and transfect the EPCs. Stain the EPCs with LacZ kit and calculate the transfection efficiency. Results The blue stain cells were cells transfected successfully with AD5F35LacZ under the optical microscope. The transfection efficiencies of adenovirus to EPCs were different under the premise of the different multiplicity of infection(MOI). In a certain range, the transfection efficiencies rise with the MOI rise. When MOI was 400,the proportion of blue stain cell is the highest, which was 98.38%±1.25%. Conclusion Recombinant adenovirus can transfect EPCs successfully. The transfection efficiencies rise with the MOI rise. When the MOI is 400,the transfection efficiency is the highest.
Objective To establish the three diamension-model and to observe the contribution of endothelial progenitor cell (EPC) in the angiogenesis and its biological features. MethodsEPC was obtained from the rats’ peripheral blood. Its cultivation and amplification in vitro were observed, and the function of the cultural EPC in vitro was detected. The three diamension-model was established and analyzed. ResultsEPC was obtained from the peripheral blood successfully. The proliferation of the EPC which induced with VEGF(experimental group) was better than that without VEGF （control group） at every different phase (P＜0.01). It was found that EPC grew into collagen-material from up and down in the three diamension-model, and its pullulation and infiltration into the collagen were seen on day 1 after cultivation. With the time flying, there were branch-like constructions which were vertical to the undersurface of collagen and interlaced to net each other. It showed that in experimental group the EPC grew fast, its infiltration and pullulation also were fast, the branch-like construction was thick. But in control group, the EPC grew slowly, infiltration and pullulation were slow, the branch-like construction was tiny and the depth of infiltration into collagen was superficial. The number of new vessels in experimental group was larger than that in the control group at every different phase (P＜0.01). ConclusionRat tail collagen can induce EPC involved in immigration, proliferation and pullulation in angiogenesis. The three-diamension model of EPC can be used to angiogenesis research. VEGF can mobilize and induce EPC to promote the angiogenesis.
Objective To compare canine decel luarized venous valve stent combining endothel ial progenitor cells (EPC) with native venous valve in terms of venous valve closure mechanism in normal physiological conditions. Methods Thirty-six male hybrid dogs weighing 15-18 kg were used. The left femoral vein with valve from 12 dogs was harvested to prepare decelluarized valved venous stent combined with EPC. The rest 24 dogs were randomly divided into the experimental group and the control group (n=12 per group). In the experimental group, EPC obtained from the bone marrowthrough in vitro ampl ification were cultured, the cells at passage 3 (5 × 106 cells/mL) were seeded on the stent, and the general and HE staining observations were performed before and after the seeding of the cells. In the experimental group, allogenic decelluarized valved venous stent combined with EPC was transplanted to the left femoral vein region, while in the control group, the autogenous vein venous valve was implanted in situ. Color Doppler Ultrasound exam was performed 4 weeks after transplantation to compare the direction and velocity of blood flow in the distal and proximal end of the valve, and the changes of vein diameter in the valve sinus before and after the closure of venous valve when the dogs changed from supine position to reverse trendelenburg position. Results General and HE staining observations before and after cell seeding: the decelluarized valved venous stent maintained its fiber and collagen structure, and the EPC were planted on the decelluarized stent successfully through bioreactor. During the period from the reverse trendelenburg position to the starting point for the closure of the valve, the reverse flow of blood occurred in the experimental group with the velocity of (1.4 ± 0.3) cm/s; while in the control group, there was no reverse flow of blood, but the peak flow rate was decreased from (21.3 ± 2.1) cm/s to (18.2 ± 3.3) cm/s. In the control group, the active period of valve, the starting point for the closure of the valve, and the time between the beginning of closure and the complete closure was (918 ± 46), (712 ± 48), and (154 ± 29) ms, respectively; while in the experimental group, it was (989 ± 53), (785 ± 43), and (223 ± 29) ms, respectively. There was significant difference between two groups (P lt; 0.05).After the complete closure of valve, no reverse flow of blood occurred in two groups. The vein diameter in the valve sinus of the experimental and the control group after the valve closure was increased by 116.8% ± 2.0% and 118.5% ± 2.2%, respectively, when compared with the value before valve closure (P gt; 0.05). Conclusion Canine decelluarized venous valve stent combined with EPC is remarkably different from natural venous valve in terms of the valve closure mechanism in physiological condition. The former rel ies on the reverse flow of blood and the latter is related to the decreased velocity of blood flow and the increased pressure of vein in the venous sinus segment.
ObjectiveTo compare the biological features of early and late endothelial progenitor cells (EPCs) by isolating and culturing early and late EPCs from the human peripheral blood so as to find some unique properties of EPCs and to propose a suitable strategy for EPCs identification. MethodsMononuclear cells were isolated from the human peripheral blood using density gradient centrifugation. Then, the cells were inoculated in human fibronectin-coated culture flasks and cultured in endothelial cell basal medium 2. After 4-7 days and 2-3 weeks culture, early and late EPCs were obtained respectively. The morphology, proliferation potential, surface markers, cytokine secretion, angiogenic ability, and nitric oxide (NO) release were compared between 2 types of EPCs. Meanwhile, the human aortic endothelial cells (HAECs) were used as positive control. ResultsThe morphology of early and late EPCs was different:early EPCs formed a cell cluster with a spindle shape after 4-7 days of culture, and late EPCs showed a cobblestone appearance. Late EPCs were characterized by high proliferation potential and were able to form capillary tubes on Matrigel, but early EPCs did not have this feature. Both types EPCs could ingest acetylated low density lipoprotein and combine with ulex europaeus Ⅰ. Flow cytometry analysis showed that early EPCs did not express CD34 and CD133, but expressed the CD14 and CD45 of the hematopoietic stem cell markers;however, late EPCs expressed CD31 and CD34 of the endothelial cell markers, but did not express CD14, CD45, and CD133. By RT-PCR analysis, the expressions of vascular endothelial growth receptor 2 and vascular endothelial cadherin in early EPCs were significantly lower than those in the late EPCs and HAECs (P<0.05), but no significant difference was found in the expression of von Willebrand factor and endothelial nitric oxide synthase (eNOS) between 2 type EPCs (P>0.05). The concentrations of vascular endothelial growth factor, granulocyte colony-stimulating factor, and interleukin 8 were significantly higher in the supernatant of early EPCs than late EPCs (P<0.05). Western blot assay indicated eNOS expressed in both types EPCs, while the expression of eNOS in late EPCs was significantly higher than early EPCs at 5 weeks (P<0.05). Both cell types could produce similar amount of NO (P>0.05). ConclusionThe expression of eNOS and the production of NO could be used as common biological features to identify EPCs, and the strategy of a combination of multiple methods for EPCs identification is more feasible.
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.
ObjectiveTo review the research progress of neural regulation mechanism of vasculogenesis. MethodsThe relevant literature on neural regulation mechanism of vasculogenesis was extensively reviewed. ResultsNeural regulation of vasculogenesis depends on synergistic effect among various cells of neurovascular unit, and co-participation of multiple cytokines, and it is closely related to a variety of repair mechanism, such as nerve regeneration and synaptic plasticity, but the specific mechanism need to be further investigated. ConclusionThe research of the neural regulation mechanism of vasculogenesis will contribute to further understanding repair mechanism of nerves and vessels injuries.