Objective To investigate the characteristics and cytocomptibility of porcine aorta fixed with genipin in vitro and to provide the proper biomaterials for fabrication of esophageal prosthesis. Methods The porcine aortas were treated by genipin for 7min to 7days, were then examined with naked-eye and light microscope. Subsequently, the fixation index determination and the biomechanics test were also performed. The cytotoxicity of the genipin-fixed materials was evaluated in vitro by MTT assay using a mouse -derived established cell line of L-929 fibroblasts as test cells. Results The experimental results indicated that the antigenicity of porcine aorta tissues could be diminished by genipin through getting rid of cell in the porcine aorta tissues and reducing the level of free amino groups in the porcine aorta tissues. The structural integrity of porcine aorta tissues can be preserved after treating with genipin. It was also found that the genipin-fixed porcine aorta tissues appeared more toughness and visco-elasticity. The RGR of genipin-fixed porcine aorta tissues was high which presumed a low cytotoxicity of this material. Conclusion The Genipin-fixed porcine aorta should be a promising material for fabricating esophageal prosthesis or fabricating scaffold of tissue-engineered esophagus.

BACKGROUND:Our previous studies have shown that strontium-doped calcium polyphosphate containing low-dose strontium appears to have a significant effect on angiogenesis-related behaviors of monocultured umbilical vein endothelial cells and osteoblasts.
OBJECTIVE:To investigate the effect of strontium-doped calcium polyphosphate on angiogenesis-related behaviors of umbilical vein endothelial cells and osteoblasts co-cultured, including celladhesion, spreading, proliferation, as wel as the protein secretion of vascular endothelial growth factor and basic fibroblast growth factor from co-culture system in vitro.
METHODS:Human umbilical vein endothelial cells and osteoblastic cells (MG63) were utilized in this study. cells from passage 3 were used for preparation of the cel-scaffold constructs. After placed in 24-wel plate at a ratio of 2:1, human umbilical vein endothelial cells and MG63 cells were seeded onto strontium-doped calcium
polyphosphate, calcium polyphosphate and hydroxyapatite scaffolds and co-cultured for 7 days. The vascular endothelial growth factor and basic fibroblast growth factor protein levels were determined through a double ligand enzyme-linked immunosorbent assay. The colorimetric 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay was performed to quantify the effect of scaffolds on cellproliferation.
RESULTS AND CONCLUSION:Compared with those on calcium polyphosphate and hydroxyapatite scaffolds, cells on strontium-doped calcium polyphosphate scaffolds attached and spread better with a significantly improved cellproliferation. More importantly, the vascular endothelial growth factor and basic fibroblast growth factor expressions were significantly higher in the strontium-doped calcium polyphosphate group than the other two groups (P<0.05), indicating strontium-doped calcium polyphosphate can up-regulate levels of vascular endothelial growth factor and basic fibroblast growth factor proteins.

This study was intended to investigate the crosslinking characteristics of a new crosslinking agent-oxidized sodium alginate (ADA), which might provide an ideal biological crosslinking reagent for the construction of soft tissue bioprostheses. Glutaraldehyde and genipin, which have been typically used in developing bioprostheses, were used as controls. The porcine aortas were treated by these three crosslinking agents for 15 min to 72 h and the fixation index was determined. Subsequently, the mechanical property and cytocompatibility of fixed tissues were also tested. The results indicated that fixed tissues by ADA were comparable as glutaraldehyde and superior to genipin controls in fixative efficiency. It was also found that tissues fixed by ADA were comparable as genipin and superior to glutaraldehyde controls in cytocompatibility and were similar to natural tissues in mechanical property. The results of in vitro study demonstrated that ADA could be a promising crosslinking reagent for biological tissue fixation.
Alginates ; chemistry ; pharmacology ; Animals ; Aorta ; cytology ; metabolism ; Biocompatible Materials ; metabolism ; Cross-Linking Reagents ; chemistry ; pharmacology ; Extracellular Matrix ; metabolism ; Glucuronic Acid ; chemistry ; pharmacology ; Hexuronic Acids ; chemistry ; pharmacology ; Swine ; Tissue Engineering ; methods ; Tissue Fixation ; Tissue Scaffolds

BACKGROUND: Ions doping is an important method for the modification of bioceramic.OBJECTIVE: To evaluate a novel co-substituted bioceramic scaffolds as bone repair material.METHODS: The microstructure and crystallization of the scaffolds were detected by scanning electron microscope and X-ray diffraction. Compression strength test,degradation test and cell culture experiment were assumed to evaluate the properties of KSCPP in vitro. After a short period of muscle pouches implantation,the performance of KSCPP in vivo was evaluated.RESULTS AND CONCLUSION: The results show that KSCPP scaffold has a higher compressive strength and degradation rate. Moreover,the MTT assay and implantation test reveal that the KSCPP scaffold exhibits lower cytotoxicity and better tissue biocompatibility than CPP and HA. The study proved the great potential of KSCPP in bone repair applications.

Purpose To investigate the effect of 5'-nucleotidase from Trimeresurus albolabris venom on platelet aggregations and its mechanism.Methods Piatelet aggregations induced by ADP,AA and PAF,respectively.were measured by turbidimetric method after platelet incubated with 5'-nucleotidase.Results 5'-nucleotidase significantly inhibited platelet aggregations induced by ADP,AA and PAF in a dose-dependent manner.Washed platelet inhibition experiment and the effect of Adenosine,CP/CPK on platelet aggregations showed that platelet aggregations inhibited by 5'-nucleotidase were associated with ADP hydrolysis and adenosine accumulation.The effect of ASA on platelet aggregations showed that the enzyme inhibited platelet aggregations probably by blocking the formation of TXA2.Conclusion 5'-nucleotidase from Trimeresurus albolabris venom inhibited platelet aggregations through ADP hydrolysis and adenosine accumulation,and maybe it is related to blocking the formation of TXA2.

While introducing the indications of low-density lipoprotein (LDL) apheresis, LDL absorption systems were reviewed generally. As the key components for binding LDL, four kinds of ligands which are synthesized by different principles are: 1. Positively charged peptides designed according to state charge force between ligand and LDL; 2. Peptides designed according to structural characteristics of the binding site between LDL and its receptors; 3. Antibody of Lp (a) obtained by immunizing mammals with designed peptides with the characteristics of Lp (a); 4. Segments of LDL binding proteins (LBPs) synthesized with genetic engineering method based on the specific binding of LBPs to LDL. Requirements of matrices carrying these ligands are also considered. Finally, future developments in treatments of familial hypercholesterolemia by means of blood purification using synthesized peptides are overlooked.
Adsorption ; Drug Carriers ; Drug Design ; Female ; Hemoperfusion ; instrumentation ; methods ; Humans ; Hyperlipoproteinemia Type II ; blood ; therapy ; Ligands ; Lipoproteins, LDL ; blood ; isolation & purification ; Male ; Peptides ; chemical synthesis ; therapeutic use ; Receptors, LDL ; chemistry

BACKGROUND: Strontium-doped calcium polyphosphate (SCPP) is a new type of bone repair materials with good biocompatibility and controlled degradation. The preliminary studies of our group indicate their role in promoting angiogenesis,but its mechanism is unclear.OBJECTIVE: By co-culturing osteoblasts ROS17/2.8 with SCPP in vitro to observe cell proliferation and the secretion of vascular endothelial growth factor (VEGF).DESIGN, TIME AND SETTING: A contrast study was performed at the Laboratory of Tissue Engineering of Sichuan University from October 2008 to June 2009.MATERIALS: A series of calcium polyphosphate (CPP) respectively containing 0%, 1 %, 2%, 5%, 8%, and 10% Sr~(2+) were prepared. ROS17/2.8 osteoblastic cell strain was provided by Laboratory of Transplantation Immunity and Transplantation Engineering, West China Hospital, Sichuan University.METHODS: ①Preparation of cell scaffold complexes: The materials were placed in 24-well plates, then 300 μL cell suspension with a concentration of 2×10~7 cells/Lwas inoculated into each hole. These complexes were cultured for 14 days and the liquid was changed every two days. ②These complexes were measured by MTT assay to observe the proliferation of osteoblasts on the 1~(st), 3~(rd), 5~(th), 7~(th), 10~(th) and 14~(th) days, respectively. ③ The centrifugal supernatant of the complex cultured for seven days was measured by ELISA assay to check the secretion of VEGF.MAIN OUTCOME MEASURES: The proliferation of osteoblastic cells on SCPP and CPP was observed. The amount of VEGF protein secreting from osteoblastic cells was detected.RESULTS: The results of MTT showed that, compared with the CPP group, SCPP groups could promote the proliferation of osteoblasts, and 8% SCPP group was the best; ELISA results showed that, compared with the CPP group, SCPP groups could increase the amount of VEGF protein secretion, of which the promoting role of 8% SCPP was the most obvious (P < 0.05).CONCLUSION: When cultured with osteoblasts, SCPP can promote cell proliferation, and can significantly increase the secretion of VEGF; moreover, 8% SCPP is the best, which reveals a certain mechanism of its promoting angiogenesis.

BACKGROUND: Strontium-doped calcium polyphosphate (SCPP), as a new repairing material, has been demonstrated to have favorable biocompatibility and biodegradability and some effects on promoting self-angiogenesis. However, the mechanism remains still unknown. OBJECTIVE: Endothelial cells were cultured with SCPP scaffolds in vitro, as well as the cell proliferation and angiogenic factor matrix metalloproteinase-2 (MMP-2) secretion were observed. DESIGN,TIME AND SETTING: A contrast study was performed at the Laboratory of Tissue Engineering of Sichuan University from September 2008 to April 2009. MATERIALS: A series of calcium polyphosphate (CPP) respectively containing 1 %, 2%, 5%, 8%, and 10% Sr~(2+) were prepared.METHODS: ① Materials were plated on 24-well culture plate,and endothelial cell suspension (300 μL) were seeded on 24-well culture plate at the concentration of 3×10~7/L and cultured with 200 uL RPMI1640 culture media. Endothelial cell proliferation was observed using MTT method at days 1,3,5, and 7 after culture. ② CPP and 8% SCPP were plated on 24-well culture plate, and endothelial cell suspension (300 uL) was then incubated in 24-well culture plate at the concentration of 1x10~8/L and cultured with 600 uL RPMI1640 culture media. The morphology of endothelial cells was observed by scanning electron microscopy (SEM) at day 5 after culture.③ Endothelial cells were co-cultured with SCPP of various Sr~(2+) contents for 5 days. After confluence, cells were centrifuged to obtain supernatant. Angiogenic factor MMP-2 secretion was evaluated by ELISA assay.MAIN OUTCOME MEASURES: The proliferation and morphology of endothelial cells on SCPP and CPP were observed. The amount of endothelial cells-derived MMP-2 protein secretion was detected. RESULTS: MTT method demonstrated that the proliferation of endothelial cells on the 8% SCPP scaffold showed a higher level compared to CPP, and other SCPP groups. Scanning electron microscope results suggested that endothelial cells on 8% SCPP had a better growth status and biological activity. ELISA results indicated that angiogenic factor MMP-2 expression on the SCPP was promoted compared with that of CPP, and 8% SCPP showed the highest expression (P < 0.05). CONCLUSION: SCPP has good compatibility with endothelial cells,promoting angiogenesis and enhancing the angiogenic factor MMP-2 expression.

Plasma fractionation membrane is very important in double filtration plasmapheresis. We studied a new polyethersulfone hollow f iber membrane plasma fractionator and evaluated the effect of time, transmembran e pressure (TMP) and mean shear rate on the sieving coefficient (SC) during memb rane plasma fractionation. The sieving coefficients of various proteins reached their maximum values at 40 min at the plasma flow rate QI=30ml/min and plasma filtrated flow rate QF=20ml/min. The QF increased with the increase of TMP, and the point of the intersection of the curve of the QF vs. TMP and the SC vs . TMP was regarded as the ideal condition for plasma fractionation. The plasma filtrated rate PFR=QF/QI=0.6～0.7. The TMP changed with the change of the mea n shear rate, and the mean shear rate had little effect on the SC. The data is o f significance to the application of plasma fractionation membrane.

Today, the blood vessel substitutes are in large demand for coronary and peripheral bypass procedures, and the demand cannot be met by conventional sources. This problem will be solved by applying tissue-engineered blood vessel in clinics. The prefabrication of vascular scaffold will be involved in engineering a blood vessel substitute. Biological tissues are important biomaterials fabricating vascular scaffold which can offer better constructs for adhesion and growth of cells onto synthetic materials. Because of immediate degradation of biological tissues obtained from the abattoir, cadaver or patient and the presence of antigenicity in allogenic or xenogenic tissues, the fresh biological tissues can not directly be preserved and applied. The use and preservation of these natural biomaterials have typically required pre-treatment aimed at (1) reducing the antigenicity of the materials, (2) enhancing the resistance of the materials to enzymatic degradation, (3) stabilizing the structure of the tissues and maintaining their mechanical properties. Physical and chemical methods for the pre-treatment of biological tissues are available. The predominant chemical agents that have been investigated for the pre-treatment of biological tissues for vascular scaffold are glutaraldehyde, polyepoxy compound, carbodiimide, genipin and proanthocyanidin. Typical and particularly promising physical pre-treatment of biological tissues for vascular scaffold is dye-mediated photooxidation. The crosslinking mechanisms of all classes of pre-treatments and the effects of pre-treatments on antigenicity, biostability, mechanical properties, cytoxicity and calcification of treated tissues are described in this article. The advantages and disadvantages of all pre-treatments are also reviewed. The trend of pre-treatment of biological tissues is to investigate and exploit the naturally occurring crosslinking reagent with less cytoxicity. Meanwhile, dye-mediated photooxidation crosslink is also a promising pre-treatment which should be widely applied in vascular scaffold.
Biocompatible Materials ; Bioprosthesis ; Blood Vessel Prosthesis ; Cross-Linking Reagents ; Ethyldimethylaminopropyl Carbodiimide ; Glutaral ; Humans ; Iridoid Glycosides ; Iridoids ; Materials Testing ; Pyrans ; Stents ; Tissue Engineering