15 patients suffering thromboangiitis obliterans with the occlusion of three branches below popliteal artery were treated by the operation of vein-arterification compounded femoral and popliteal planes at this hospital from 1990 to 1995. It is proved by clinical observation and correspondence with 15 patients that the symptoms ammeliated quickly and surely at the near future and forward blood supply lasted so as to avoid the complications of limb edema and heart failure. So the authors consider that the composite vein-arterification has a good anatomical and physical basis and suits to sufferers with the occlusion below popliteal vessels caused by different reasons, the principle of vein-arterification is to select the trunk artery of no pathological changes and not the collateral deep vein, but should select small-median superficial vein far away from pathological artery.
The establishing of myocardial tissue engineering techniques not only solve a series of issues that generate in cell and tissue transplantation after myocardial infarction, but also create a platform for selecting better materials and transplantation techniques. However, both experimental animal studies and recent clinical trials indicate that current transplantation techniques still have many defects, mainly including lack of suitable seed cells, low survival rate and low differentiation rate after transplantation. In this context, extracellular matrix （ECM）, as myocardial tissue engineering scaffold materials, has gained increasing attention and become a frontier and focus of medical research in recent years. ECM is no longer merely regarded as a scaffold or a tissue, but plays an important role in providing essential signals to influence major intracellular pathways such as cell proliferation, differentiation and metabolism. The involved models of ECM can be classified into following types：natural biological scaffold materials, synthetic polymer scaffold materials and composite scaffold materials with more balanced physical and biological properties. This review mainly introduces research progress of ECM in myocardial tissue engineering and ECM materials.
Objective To develop a tissue engineering scaffold by using 4arm branched polyethylene glycol-VS (PEG-VS) crosslinked with decellularized valved conduits (DVC), and to research on its mechanical and biological functions. Methods The valved aortic conduits of rabbits were taken and decellularized by trypsin method and then were crosslinked with 4arm branched PEG-VS to construct the composite scaffolds (CS). The functions of decellularized valved conduits and the composite scaffolds were tested by mechanics test system. Thirty New Zealand white rabbits were equally and randomly assigned to one of the three groups: the control group, the DVC group, and the CS group. Valved aortic conduits, decellularized valved conduits and composite scaffoldswere transplanted into the common carotid artery of the abovementioned three groups of rabbits respectively. Twentyeight days after the operation, patency of the transplants was tested by Color Doppler ultrasound; micromorphology and inflammatory infiltration were observed by hematoxylin eosin（HE） staining andscanning electron microscope (SEM)，and endothelialization of composite scaffolds was detected by immunofluorescent staining. Results A series of biomechanical analyses revealed that the composite scaffolds had highly similar mechanical properties as fresh tissue, and had superior elastic modulus (P=3.1×10-9) and tensile strength (P=1.1×10-6) compared with decellularized valved conduits. Color Doppler ultrasound revealed that the graft patency for the CS group was better than the control group (P=0.054) and the DVC group (P=0.019), and the intraaortic thrombosis rate and distortion rate decreased significantly. HE staining and SEM showed that the endothelialization of composite scaffolds in the CS group was significantly higher than the other two groups with the endothelial cells evenly distributed on the scaffolds. The [CM(159mm]immunofluorescent staining indicated that the positive rate of the endothelial cell marker CD34 was higher than the other two groups. Conclusion The composite scaffolds using 4arm branched PEGVS crosslinked with DVC have great mechanical and biological properties.
Objective To evaluate midterm and longterm clinical outcome of bilateral internal mammary artery composited Y grafts for coronary artery bypass grafting (CABG)， analyze risk factors for late death ，and to improve surgical results. Methods Between January 2000 and May 2004, One hundred and sixtyfive patients underwent bilateral internal mammary artery grafts for CABG, The clinical data, postoperative complications and survival results were retrospectively reviewed and analyzed. The preoperative and postoperative cardiac function was compared. All factors that may have affected the survival were analyzed by logistic regression, to identify significant variables associated with late death. Results Total 561 anastomosis sites of internal mammary arteries were completed with each patient received an average of 3.4 grafts. There were no perioperative deaths. There were 16 patients with postoperative complications including recurrent angina, myocardial infarction, low cardiac output syndrome, sternal infection and so on. All patients were treated conservatively without reoperation. One hundred sixty patients（97%）were followed up of 5.6±1.2 years, there were 23 late deaths including 10 patients of cardiac related death in which 3 had recurrent myocardial infarction, 4 heart failure, and 3 arrhythmia; 13 patients of nocardiac related death in which 4 upper gastrointestinal hemorrhage, 3 cancer and 6 uncertain cause. 25 patients had major cardiac related events including recurrent angina 18, myocardial infarction 4, repeated revascularization 3. Left ventricular ejection fraction [CM(159mm]was significantly improved as compared with that before operation（54%±6% vs. 43%±12%, Plt;0.05）. The 1-, 3-, 5-year actuarial survival rates and eventfree rates were 98.2%±0.3%, 96.2%±0.5%, 90.5%±1.9% and 95.5%±1.2%, 91.3%±2.1%, 86.6%±1.5%, respectively. According to statistical analysis, univariate analyses had proved that advancing age＞65 years，diabetes，ejection fraction(EF) less than 30%，the New York Heart Association (NYHA) class Ⅲ/Ⅳ, and low cardiac output syndrome required placement of the intraaortic balloon pump were predictors associated with hospital major adverse cardiac events (Plt;0.05). Those variables entered into the logistic regression model and found to be independent predictors associated with increased late cardiac death included advancing age ＞65 years(OR=11.6), diabetes (OR=21.4), EF less than 30%(OR=37.5) and NYHA class Ⅲ/Ⅳ(OR=40.2). Conclusion Patients receiving bilateral internal mammary artery composited Y grafts have better longterm survival and reduced cardiac related events. Independent risk factors for late death are NYHA function class Ⅲ/Ⅳ, EF less than 30%, diabetes and advancing age ＞65 years.
Objective To prepare nerve growth factor (NGF)-insulin composite gel and observe the effects of NGF-insulin composite gel on deep second degree scald wound healing in diabetic rats. Methods Carbomer 980, NGF (4 000 U), and insulin (800 U) were used to prepare the insulin gel, NGF gel, and NGF-insulin composite gel. The character of NGF-insulin composite gel was observed, and the in vitro drug release was tested. Seventy-five SPF Wistar male rats, weighing 200-250 g, were divided into 5 groups randomly, 15 rats each group: normal control group (group A), diabetes control group (group B), insulin gel treatment group (group C), NGF gel treatment group (group D), and NGF-insulin composite gel treatment group (group E). The type 1 diabetes rat model was established by intraperitoneal injection of Streptozotocin (55 mg/kg) in groups B, C, D, and E, while the rats in group A were injected with the same dose of citric acid and calcium citrate buffer. After modeling success, deep second degree scald wound on the back was made with constant temperature water bath box. Wounds were treated with carbomer blank gel in groups A and B, with insulin composite gel in group C, with NGF gel in group D, and with NGF-insulin composite gel in group E, once a day. At 3, 7, 11, 15, and 21 days after injury, the scald wound healing was observed and healing rate was calculated; the full-thickness skin specimens were harvested from 3 rats of each group for histological and immuohistochemical staining observation. Results The NGF-insulin composite gel was clear and transparent, and had good moisture retention capacity and adhesion; it was easy to apply and clean up. The drug release in vitro lasted more than 24 hours and maintained for 30 days. No rat died during the experiment. At 3 days after injury, wound area did not reduce in all groups; at 7, 11, 15, and 21 days, group E had the highest wound healing rate, and group B had the lowest; significant differences were found between group E and group B and when compared with the other groups (P lt; 0.05). HE staining showed that group E surpassed other groups in the growth of granulation tissue and collagen fiber. Immunohistochemical results showed that the CD34 and proliferating cell nuclear antigen (PCNA) expressed at 3 days, and the number of positive cells increased gradually with time; the microvessel density and PCNA expression were highest in group E and were lowest in group B, showing significant differences when compared with the other groups and between group E and group B (P lt; 0.05). Conclusion NGF-insulin composite gel can improve deep second degree scald wound healing in diabetic rats.
【Abstract】 Objective To evaluate the long-term effectiveness of composite grafts of acellular dermal matrix (ADM)and autologous spl it-thickness skin in repairing deep burn wounds. Methods Between June 2002 and December 2008, 30 patients (42 wound) were treated. There were 25 males and 5 females, aged 3-52 years with a median age of 31 years. Of them, 24 burned patients had 35 wounds, including 23 deep second degree and 12 third degree wounds with a mean disease duration of 24 days (range, 3-45 days); 6 patients with hyperplastic scar had 7 wounds with a mean disease duration of 16 days (range, 9-21 days). The wound locations were neck (2 wound), hand (4 wounds), forearm and elbow (8 wounds), shoulder (3 wounds), poples (6 wounds), laps (4 wounds), ankle and legs (15 wounds), and the area of wounds ranged from 10 cm × 10 cm to 30 cm × 20 cm. After thorough debridement, tangential excision, and scar excision, ADM and autologous spl it-thickness skin graft were used to repair the wounds by one-step method. Results After operation, composite skin graft survived completely in 39 wounds of 27 patients, with a survival rate of 92.9%; partial necrosis occurred in 3 wounds of 3 patients (7.1%), and healed after dressing change and secondary skin graft. The patients were followed up 30-34 months (mean, 32 months) postoperatively. The appearance of the composite grafts were smooth and soft with good elasticity and low pigmentation. The activity and function of limbs recovered well. No scar hyperplasia was observed at the donor sites. Conclusion It can achieve good outcomes in appearance and function to use ADM and autologous spl it-thickness skin graft for repairing deep burn wounds in functional regions.
Objective To introduce the research progress in the immune of composite tissue allotransplantation. Methods The related articles were reviewed to summarize the immune characteristics, experimental developments, and cl inical experiences of composite tissue allotransplantation. Results Composite allogeneic tissue is on the body surface, including the composition of the complex with high antigenicity. There are a lot of differences in the immune responsesbetween composite tissue allotransplantation and organ transplantation, such as immunosuppressant protocol, rejectiondiagnosis, and chronic rejection. Conclusion In the next study, it is urgently needed to learn these experiences and toestabl ish the special standard of composite tissue allotransplantation in induction of immune tolerance, local medication, and rejection diagnosis.
Objective To review the current status and problems in the developing scaffolds for the myocardial tissue engineering appl ication. Methods The l iterature concerning the myocardial tissue engineering scaffold in recent years was reviewed extensively and summarized. Results As one of three elements for tissue engineering, a proper scafold is veryimportant for the prol iferation and differentiation of the seeding cells. The naturally derived and synthetic extracellular matrix (ECM) materials aim to closely resemble the in vivo microenvironment by acting as an active component of the developing tissue construct in myocardial tissue engineering. With the advent and continuous refinement of cell removal techniques, a new class of native ECM has emerged with some striking advantages. Conclusion Through using the principle of composite scaffold, computers and other high-technology nano-polymer technology, surface modification of traditional biological materials in myocardial tissue engineering are expected to provide ideal myocardial scaffolds.
Objective To summarize the method and the cl inical outcome of repairing both toe extensor tendon and dorsal foot wounds with anterolateral thigh flap. Methods Between February 2007 and May 2009, 11 patients with toe extensor tendon and dorsal foot defect were treated with anterolateral thigh flap. There were 8 males and 3 females with a medianage of 45 years (range, 10-60 years). The causes of injury were sharp injury in 3 cases, machine crush injury in 3 cases, and traffic accident injury in 5 cases, including 7 cases of fresh wounds with a disease duration of 2-8 hours and 4 cases of old wounds with a disease duration of 3-15 days. The size of wound ranged from 6 cm × 5 cm to 25 cm × 15 cm. All cases compl icated by toe extensor tendon defect, which were located at the 2nd-5th toes in 1 case, 3rd-5th toes in 1 case, 2nd-4th toes in 2 cases, 2nd and 3rd toes in 3 cases, 1st and 2nd toes in 1 case, and 1st toe in 3 cases. In the first stage, the anterolateral thigh flap ranged from 8 cm × 7 cm to 27 cm × 15 cm was used to repair defect and fascia lata was used to bridge two ends of digitorum longus tendon; the donor site was sutured or repaired with the skin graft. The second stage was performed after 2-3 months, tenolysis for tendon was performed, and fascia lata was spl it into tendon-l ike shape; and the toe functional exercises were done. Results All flaps survived completely after the first stage, wounds healed by first intention; the donor skin graft survived and incisions healed by first intention. At 7 days after the second stage, marginal necrosis occurred in 3 flaps (0.5-2.0 cm in width), and healed after 15-20 days of dressing change; the other flaps survived, and incisions healed by first intention. Eight patients were followed up 12-18 months (mean, 15 months). Excepts 4 sl ight bulky flaps, the other flaps had satisfactory appearance and soft texture with two points discrimination of 1-3 cm. During the follow-up, part of the dorsiflexion function recovered in 5 patients (5-40°), andflexion function was normal; 3 dorsiflexion function disappeared without effect on the function of toe flexion, and the patients could walk normally. No toe ptosis occurred. Conclusion Appl ication of the anterolateral thigh flap can repair toe extensor tendon and dorsal foot wounds with short treatment time and less damage at the donor site, so it can avoid toe ptosis after surgery and achieve excellent cl inical results.
Objective To review the appl ication of collagen and biodegradable polymer composite scaffolds in vascular tissue engineering, and describe the multi-layering vascular scaffolds of collagen-based material in recent years. Methods The l iterature concerning collagen composite scaffold production for scaffold of vascular tissue engineering was extensively reviewed and summarized. Results As one of the structural proteins in natural blood vessel, collagen is widely used in vascular tissue engineering because of good biocompatibil ity, biodegradabil ity, and cell recognition signal. The vascular scaffolds with biological activity and good mechanical properties can be made by collagen-polymer composite materials. In addition, the structure and function of the natural blood vessel can be better simulated by multi-layering vascularscaffolds. Conclusion Collagen-polymer composite material is the hot spot in the research of vascular scaffolds, and multilayering vascular scaffolds have a brill iant future.