Decellularized aorta of fetal pigs as a potential scaffold for small diameter tissue engineered vascular graft.

BACKGROUND: For cardiovascular tissue engineering, acellularized biomaterials from pig have been widely investigated. Our purpose was to study mechanical properties and biocompatibility of decellularized aorta of fetal pigs (DAFP) to determine its potential as scaffold for small diameter tissue engineered vascular graft. METHODS: Descending aorta of fetal pigs was removed cells using trypsin, ribonuclease and desoxyribonuclease. Mechanical properties of DAFP were evaluated by tensile stress-strain and burst pressure analysis. Assessment of cell adhesion and compatibility was conducted by seeding porcine aortic endothelial cells. To evaluate biocompatibility in vivo, DAFP was implanted subcutaneously into adult male Sprague Dawley rats for 2, 4 and 8 weeks. RESULTS: Histochemistry and scanning electron microscopy examination of DAFP revealed well-preserved extracellular matrix proteins and porous three-dimensional structures. Compared with fresh aorta, DAFP had similar ultimate tensile strength, axial compliance and burst pressure. Cell culture studies in vitro showed that porcine aortic endothelial cells adhered and proliferated on the surfaces of DAFP with excellent cell viability. Subdermal implantation demonstrated that the DAFP did not show almost any immunological reaction and exhibited minimal calcification during the whole follow-up period. CONCLUSION: The DAFP has the potential to serve as scaffolds for small diameter tissue engineered vascular graft.

[Experimental study of compatibility between chondrocytes and allogenic cartilage microparticle acellular tissue matris in vitro].

OBJECTIVE: To construct tissue engineered cartilage using cartilage microparticle acellular tissue matrix (CMACTM) as scaffold. METHODS: To determine the content of hydroxyproline, glycosaminoglycan and DNA of CMACTM prepared from sheep's articular cartilage with multistep enzymic method, and to analyze CMACTM with gross observation, histology and scanning electron microscopy. Allogenic chondrocytes were mixed with CMACTM and cultured in vitro from 0 to 35 days. Observations through inverted microscope, scanning and transmission electron microscope, quantifications of hydroxyproline, glycosaminoglycan and DNA in the composite, cells adhesion rate were applied to analyze the results. RESULTS: The diameter of CMACTM was 0.100-0.154 mm, which contain extracellular matrix only. Hydroxyproline, glycosaminoglycan and DNA quantifications in CMACTM were 204.374 +/- 3.120 microg/mg, 18.302 +/- 2.037 microg/mg and 0.042 +/- 0.013 microg/mg respectively. Allogenic chondrocytes enclosed CMACTM tightly, hydroxyproline, glycosaminoglycan and DNA quantifications in the composite of the two formers increased with difference on 7th day compared with that on 0 day, reached to the peaks on 14th day (hydroxyproline, DNA) and on 21st day (glycosaminoglycan), and retained at a high level on the following days. Cells adhesion rate was 92%. CONCLUSION: Allogenic CMACTM possessed satisfactory biocompatibility for chondrocytes and provided a new scaffold for cartilage tissue engineering.

[An experimental study of small-caliber tissue engineering vessels with acellular matrix].

OBJECTIVE: To observe the mechanical properties of the prefabricated connective tissue tube as blood vessel substitute and its changes after implantation at the femoral artery. METHODS: The acellular matrix tube of 8-12 cm in length with a silicone rod inside it was implanted into dog peritoneal cavity. 3 weeks later, a new formed tube around the silicone rod was transferred to the femoral artery as blood vessel substitute. The mechanical properties and histological examination of the blood vessel substitute were assessed and compared to those of the carotid artery and vein. 6 months after transfer, the patency of the blood vessels substitute was observed. The histological change was studied by light microscopy, scanning and transmitting electron microscopy. RESULTS: (1) The mechanical properties of blood vessel substitute was not as strong as artery, but better than the vein. (2) There were elastic and collagen fibers with many fibroblasts around the tube wall, but few mesothelial cells around the inner wall. All of the blood vessel substitutes (n = 6) were found to keep patency and the structure of the blood vessels substitutes became similar to femoral artery 6 months after they had been grafted to the femoral artery. CONCLUSIONS: These results suggest that tissue engineering in vivo is a good approach to construct vessels substitute. The tissue tubes made in dog's peritoneal cavity have good condition when it is used as a blood vessel substitutes.

[Biocompatibility of decellularized canine carotid artery allograft cross-linked by carbodiimide].

UNLABELLED: OBJECTIVE Crosslink decellularized canine carotid artery allograft by EDC [1-3-(dimethylamino)propyl-3-ethylcarbodiimide methiodide] and evaluate the biocompatibility of it. METHODS: Use the multi-step detergent-enzyme method to construct decellularized canine carotid artery allograft and cross-link it by EDC with the weight ratio of decellularized artery to EDC 1:1 and 1:2. Evaluate the biocompatibility of it by the cytotoxical MTT test and the rat subdermal bury test. RESULTS: Decellularized canine carotid artery cross-linked by EDC has a lower degradation rate treated by collagenase type II, the result of MTT test show that the EDC cross-linked decellularized artery has no cytotoxity and the rat subdermal bury test show that crosslinking greatly enhance the ability of decellularize artery to resist the enzyme degradation and lower the immune reaction. The more the artery was cross-linked , the more effects it has. CONCLUSIONS: Decellularized canine carotid artery cross-linked by EDC has fairly good biocompatibility and ability to resist the collagenase degradation.

[Vascular anatomy and clinical applications of the distally based superficial sural artery island flap].

OBJECTIVE: To document the vascular anatomy of the distally based superficial sural artery flap and to study the vascular anastomoses between the superficial sural artery and the septocutaneous perforators of the peroneal artery. METHODS: Ten fresh human cadavers were injected with lead oxide, gelatin and water. Twenty lags were then dissected and an overall map of the cutaneous vasculature was constructed. Vascular communications between the superficial sural artery and the lowest septocutaneous perforator of the peroneal artery was evaluated to determine the cutaneous vascular territory of the superficial sural flap. The distally based superficial sural artery island flap was used in 26 cases. RESULTS: There is constant vascular anastomosis between the superficial sural artery and the lowest septocutaneous perforator of the peroneal artery. The 26 flaps survived uneventfully except for two of partial fat necrosis. CONCLUSION: The anatomic information enhances our understanding of flap design.

[The neurovascular anatomy and its clinical implication of the rectus femoris muscle].

OBJECTIVE: The objective of this anatomic study was to investigate the intramuscular neurovascular configuration and to evaluate whether the muscle could be split into two functional units in transplantation. METHODS: Ten fresh cadavers and ten preserved cadavers were used in the study. A mixture of lead oxide, gelatin and water was injected to the femoral artery of the fresh cadaver. The rectus femoris muscle with its neurovascular pedicles was dissected and radiographed. RESULTS: Three vascular patterns of the rectus femoris muscle were found in the 40 cadaver legs. The muscle received its blood supply through a single vascular pedicle (12.5%), or a dominant pedicle with 1-2 ramified (80%), or two dominant vascular pedicles (7.5%). CONCLUSIONS: The study provided a detailed description on the intramuscular neurovascular territories of the rectus femoris muscle. Based on the neurovascular supply of the muscle, it is possible to subdivide the muscle into two functional units for segmental muscle transfer.

[Transferring neurovascular rectus femoris muscle segment for treatment of facial paralysis].

OBJECTIVE: To investigate a new technique for functional treatment of chronic facial paralysis. METHODS: Based on anatomy of intramuscular neurovascular structure in the rectus femoris muscle, 7 consecutive patients with facial paralysis were treated by using a technique of microsurgically free-transferring neurovascular rectus femoris muscle segment to the face in one-stage. Follow-ups were 10 to 24 months. RESULTS: All of the 7 patients showed significantly improvement in the appearance of the oral commissure and oral competence. No complications occurred in the donor site. CONCLUSIONS: The above mentioned technique may have the advantages of preventing the intramuscular nerve and vessel from the surgical injury during splitting the muscle. It could also maintain the transferred muscular segment in a proper tension in the recipient site.