Objective To review the latest research progress of heme oxygenase 1 (HO-1), to thoroughly understand different functions of HO-1 and its influence on osteogenesis and angiogenesis of stem cells, and to analyze HO-1 application in bone tissue engineering. Methods Domestic and international literature on HO-1 in recent years was extensively reviewed and analyzed. Results The activity of HO-1 and its enzymatic products not only have the properties of anti-inflammatory, anti-apoptosis, and cytoprotection, but also can promote angiogenesis combined with other growth factors and protect the vessel which already exist. Moreover, HO-1 has an effect on the proliferation, paracrine signaling, osteoblastic differentiation, and anti-apoptosis of stem cells. Conclusion HO-1 can be used as a multi-function growth factor in bone tissue engineering, but more investigation should emphasis on synergistic effect of each function so as to improve bone repair.
Objective To investigate the mechanism of vascular stromal fraction (SVF) at the early stage after aspirated fat transplantation. Methods Fat was harvested from 5 cases of women undergoing abdominal liposuction operation, and SVF was isolated. Aspirated fat with (group B) or without (group A) SVF was injected subcutaneously into the back of nude mice, and the grafts were harvested at 1, 3, 5, and 7 days. Graft wet weight was measured; and immunohistochemical method (CD31) was performed and the secretion of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) were qnantified by Western blot assay. Results The wet weight of transplanted adipose tissue showed an increasing tendency in groups A and B with time, and no significant difference was found between groups A and B (P gt; 0.05). At 1 and 3 days after transplantation, no CD31 positive cells was seen in 2 groups; the CD31 positive cells of group B were significantly more than those of group A at 5 and 7 days (P lt; 0.05), and the CD31 positive cells at 7 days were significantly more than those at 5 days in 2 groups (P lt; 0.05). Western blot test showed that VEGF expression reached peak at 3 days , then decreased gradually; the expression of VEGF protein in group B was significantly higher than that in group A at 1, 3, and 5 days (P lt; 0.05). The expression of HGF protein in groups A and B remained at a high level within 5 days, but it tended to decrease at 7 days, which was significantly higher in group B than that in group A (P lt; 0.05). Conclusion SVF can enhance angiogenesis by secretion of growth factors at the early stage after aspirated fat transplantation.
Objective To review the research progress of the seed cells, scaffolds, growth factors, and the prospects for clinical application of the intervertebral disc regeneration. Methods The recent literature concerning the regeneration strategies and tissue engineering for treatment of degenerative intervertebral disc disease was extensively reviewed and summarized. Results Seed cells based on mesenchymal stem cells (MSCs) and multiple-designed biomimetic scaffolds are the hot topic in the field of intervertebral disc regeneration. It needs to be further investigated how to effectively combine the interactions of seed cells, scaffolds, and growth factors and to play their regulation function. Conclusion The biological regeneration of intervertebral disc would have a very broad prospects for clinical application in future.
【Abstract】 Objective To find out the best method to prepare platelet-rich plasma (PRP) and to evaluate the effect of PRP gel on skin flap survival and its mechanism. Methods Totally, 72 Wistar rats (aged 12 weeks, weighing 250-300 g) were used for the experiment. The arterial blood (8-10 mL) were collected from the hearts of 24 rats to prepare PRP with three kinds of centrifuge methods: in group A, 200 × g centrifuge for 15 minutes, and 500 × g centrifuge for 10 minutes；in group B, 312 × g centrifuge for 10 minutes, and 1 248 × g centrifuge for 10 minutes；and in group C, 200 × g centrifuge for 15 minutes, and 200 × g centrifuge for 10 minutes. The platelet was counted in the whole blood, PRP, and platelet-poor plasma (PPP) to determine an ideal centrifuge. PRP, PPP, and the serum after first centrifuge were collected. The concentrations of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β1 (TGF-β1) were measured in the PRP, PPP, and serum using the enzyme-linked immunosorbent assay method, and PRP and PPP gels were prepared. The flaps of 11 cm × 3 cm in size were elevated on the back of 48 rats, which were divided into 3 groups: PRP gel (PRP group, n=16) and PPP gel (PPP group, n=16) were injected, no treatment was given in the control group (n=16). The flap survival rate was measured at 7 days. Histological and real-time PCR were used to count the inflammatory cells and blood vessel density, and to detect the expressions of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), PDGF-AA, and PDGF-BB mRNA at 8 hours, 24 hours, 3 days, and 7 days. Results Platelet counting showed platelet in group A was the highest. ELISA evaluation showed that the concentrations of TGF-β1 and PDGF-BB were significantly higher in PRP than in PPP and serum (P lt; 0.05). The flap survival rate was 61.2% ± 9.1% in PRP group, showing significant differences (P lt; 0.05) when compared with that in PPP group (35.8% ± 11.3%) and control group (28.0% ± 5.4%). The inflammatory cells were significantly lower and the blood vessel density was significantly higher in PRP group than in PPP group and control group (P lt; 0.05). When compared with PPP group and control group, the expressions of VEGF and PDGF-BB increased at all time after operation in PRP group; the expression of EGF increased within 24 hours; and the expression of PDGF-AA increased after 3 days. There were significant differences in PDGF-AA mRNA at 3 days and 7 days, PDGF-BB mRNA at 8 hours, VEGF mRNA at 24 hours and 3 days, and EGF mRNA at 24 hours between PRP group and PPP and control groups (P lt; 0.05). Conclusion 200 × g centrifuge for 15 minutes and 500 × g centrifuge for 10 minutes is the best PRP preparation method. PRP can improve the skin flap survival by regulating the genes involved in angiogenesis.
Objective To review the recent progress of the researches in the field of cartilage tissue engineering, and to discuss the challenges in construction of tissue engineered cartilage. Methods Literature related with cartilage tissue engineering was reviewed and analyzed. Results Some techniques have been appl ied in cl inical. As far as the seeding cells, induced pluripotent stem cells have attracted much more attention. Current strategies of scaffold designing are trying to imitate both component and structure of natural extracellular matrix. Cartilage regeneration through the autologous cell homing technique el iminate the transplantation of exotic cells and has become the hot topic. Conclusion Successful treatment of the damaged cartilage using tissue engineering method will depend on the advances of stem cell technology development, biomimetic scaffolds fabrication and proper appl ication of growth factors.
Objective To review the research progress of the current methods of inducing bone marrow mesenchymal stem cells (BMSCs) to chondrogenic differentiation in vitro so as to provide references for researches in cartilage tissue engineering. Methods Various methods of inducing BMSCs differentiation into the chondrogenic l ineage in vitro inrecent years were extensively reviewed and analyzed. Results Adding exogenous growth factors is still the mainly methodof inducing BMSCs differentiation into the chondrogenic l ineage; among the members, transforming growth factor β (TGF-β) family is recognized as the most important chondrogenic induction factor. Other important inducing factors include various chemical factors, physical factors, transgenic methods, and the microenvironmental induction. But the problems of low inducing efficiency and unstable inducing effects still exist. Conclusion The progress of chondrogenic induction of BMSCs promotes its util ization in cartilage tissue engineering. Further researches are needed for establ ishing more efficient, simpler, and safer inducing methods.
Objective To investigate the effect of machine-enzyme digestion method on the residual quantity of small intestinal submucosa (SIS) cell and the content of growth factors. Methods Fresh jejunum of pig within 4 hours after harvesting was prepared into SIS after machine digestion (removing placenta percreta, mucosa, and muscular layer), degrease,trypsinization, abstergent processing, and freeze drying. Samples were kept after every preparation step serving as groups A, B, C, D, and E, respectively (n=4 per group). And the fresh jejunum served as control group (group F, n=4). The histological alteration in each preparation process was reviewed with HE staining and scanning electron microscope (SEM). Nest-polymerase chain reaction (PCR) was used to determine the content of death associated protein 12 (DAP12), and enzyme-linked immunosorbent assay (ELISA) was appl ied to detect the content of vascular endothel ial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor β (TGF-β), tumor necrosis factor α (TNF-α). Results HE staining and SEM observation showed that there were residual cells in groups A and B, and there were no residual cells in groups C, D, and E. Nest-PCR test revealed the occurrence of DAP12 in each group. The contents of DAP12 in groups A, B, C, D, E, and F were (18.01 ± 9.53), (11.87 ± 2.35), (0.59 ± 0.27), (0.29 ± 0.05), (0.19 ± 0.04), and (183.50 ± 120.13) copy × 106/cm2. The content of DAP12 in group F was significant higher than that of other groups (P lt; 0.05), groups A and B was higher than groups C, D, and E (P lt; 0.05), there were significantdifferences among groups C, D, and E (P lt; 0.05), and there was no significant difference between groups A and B (P gt; 0.05). The ELISA test showed the content of VEGF, bFGF, TGF-β, and TNF-α in group A was significantly higher than that of groups B, C, D, and E (P lt; 0.05), and there was no significant difference among groups B, C, D, and E (P gt; 0.05). Conclusion SIS prepared by simple mechanical method has more residual cells, while the machine-enzyme digestion method can effectively remove the cells and significantly reduce the DAP12 content. This approach can not obviously reduce the growth factor content in SIS.
Objective To introduce the basic research and cl inical appl ication of the injectable bone repair biomaterials. Methods The recent original articles about the injectable bone repair biomaterials were extensively reviewed. Results The injectable bone repair biomaterials could fill irregularly shaped defects and might allow bone augmentation, both with minimal surgical intervention, and the injectable bone repair material had a good prospect by the medical profession and attach great importance to the academic material, but there were some deficiencies and shortcomings. Conclusion The injectable bone repair biomaterials may be a future approach to repair bone defect．
To compare the platelet enrichment ratio of platelet-rich plasma (PRP) prepared by different centrifuge methods and to compare the concentration of growth factors released from autologous platelet-rich gel (APG) with the whole blood. Methods Thirteen diabetic patients with refractory skin lesions were enrolled in APG treatment. ① Three kinds of centrifuge methods were selected for PRP by 11 diabetic patients: A(n=6): 529 × g for 4 minutes in the first centrifugeand 854 × g for 6 minutes in the second centrifuge; B (n=5): 313 × g for 4 minutes in the first centrifuge and 1 252 × g for 6 minutes in the second centrifuge; C (n=5): 176 × g for 5 minutes in the first centrifuge and 1 252 × g for 5 minutes in the second centrifuge. Platelet counted on the whole blood and PRP was determined. The APG, produced by combining the PRPwith thrombin and calcium gluconate (10 ∶ 1) was used by patients. ② PDGF-BB, TGF-β1, VEGF, EGF, and IGF-1 were measured in the APG and the whole blood using the enzyme-l inked immunosorbent assay method. Results ① The average platelet concentration was higher in group B [(1 363.80 ± 919.74) × 109/ L] than in groups A[(779.67 ± 352.39) × 109/ L)] and C[(765.00 ± 278.78) × 109/ L] and the platelet recovery rate was 75.2% ± 21.0% in group B. ② The concentration of growth factors all increased with the increasing platelet number. On average, for the whole blood as compared with APG, the PDGF-BB concentration increased from (145.94 ± 133.24) pg/mL to (503.81 ± 197.86) pg/mL (P lt; 0.05); TGF-β1 concentration increased from (3.31 ± 2.27) ng/mL to (5.67 ± 4.80) ng/mL (P lt; 0.05); IGF-1concentration increased from (14.54 ± 35.34) ng/mL to (110.56 ± 84.36) ng/mL (P lt; 0.05); and EGF concentration increased from (160.73 ± 71.10) pg/mL to (265.95 ± 138.43) pg/mL (P lt; 0.05). No increase was found for VEGF(P gt; 0.05). ③ There was positive correlation between the platelet concentration and PDGF-BB and TGF-β1 (r = 0.627, r = 0.437, P lt; 0.05). ④ Thirteen diabetic repractory dermal ulcers received APG treatment for 18 times, 9 ulcers (69.2%) and 10 sinuses (88.3%) were cured at the end of 12-week treatment. Conclusion The method ofgroup B is the best centrifuge method. A variety of growth factors are detected and released from the platelets at significant levels in APG. There is positive correlation between the platelet concentration and PDGF-BB and TGF-β1 .
【Abstract】 Objective To explore the interventional effect of platelet lysate (PL) on osteogenic differentiation ofBMSCs by induction in rats in vitro. Methods Twenty-four clean-grade adult Wistar rats, weighing from 250 g to 300 g, maleor female, were included in this study. PL was obtained through three times of centrifugation and repeated freeze-thaw for the blood aspirated from cardiac cavities in 16 Wistar rats. ELISA assay was conducted to detect the concentration of growth factors PDGF, TGF-β1, IGF-1 and VEGF in PL. The BMSCs harvested by flushing femurs of 8 adult Wistar rats were isolated, cultivated and expanded in vitro. The cells at the 4 passage were performed for osteogenic differentiation by induction in three groups of A (5% PL of final concentration in basic induction medium), B (1% PL of final concentration in basic induction medium), and C (no presence of PL in basic induction medium as a control). The morphological changes of the cells were dynamically observed with inverted phase contrast microscope during the whole period. At different time-points, ALP staining (7 days) and ALP/TP (2, 8, 12 days) of the cells were detected to evaluate ALP activity, and the mineral formation in extracellular martrix was examined with Al izarin red staining which provided quantitative analysis of mineral deposits. Results ELISA assay showed that the content of PDGF, TGF-β1, IGF-1 and VEGF in PL reached (300 ± 30), (140 ± 25), (80 ± 35), (70 ± 20) pg/mL, respectively. Morphological observation displayed BMSCs in group A or B gradually turned from spindle-shape to square- or polygon-shape as the morphorlogical type of osteoblast-l ike cells at 7 days. The cells in group A showed slower shape changesbut higher prol iferation than that in group B or C. Moreover, at the 20 days, the cells in group A still displayed dense gro wth and produced obviously decreased amount of mineral deposits in ECM when compared with group B or C. At the 7 days, the cells ofgroup A showed smaller amount of granules positive for ALP staining in cytoplasm when compared with groups B and C, and displayed marked reduction in ALP activity assay at the 2, 8, and 10 days compared with that of groups B and C (P lt; 0.05). At the 20 days, Al izarin red staining showed the number of mineral deposits in groups A, B and C were 7.67 ± 1.10, 12.87 ± 0.81 and 15.59 ± 0.25, respectively, while the area of mineral deposits were (161 778.70 ± 44 550.80), (337 349.70 ± 56 083.24), and (415 921.70 ± 71 725.39) pixels, respectively. The number of mineral deposits and the area of mineral deposits in group A were smaller than those in groups B and C (P lt;0.05). But there was no statistically significant difference between groups B and C (P gt; 0.05). Conclusion PL is a kind of system carrying various growth factors. Exposure of PL inhibits both ALP activity and mineral formation of BMCs in a dose-dependent way under the osteogenic induction environment.