Objective Tolerogenic DCs (Tol-DCs), a group of cells with imDC phenotype, can stably induce T cells low-reactivity and immune tolerance. We systematically reviewed the adoptive transfusion of Tol-DCs induced by different ways to prolong cardiac allograft survival and its possible mechanism. Method MEDLINE (1966 to March 2011), EMbase (1980 to March 2011), and ISI (inception to March 2011) were searched for identification of relevant studies. We used allogeneic heart graft survival time as endpoint outcome to analyze the effect of adoptive transfusion of Tol-DC on cardiac allograft. By integrating studies’ information, we summarized the mechanisms of Tol-DC in prolonging cardiac grafts. Results Four methods were used to induce Tol-DC in all of the 44 included studies including gene-modified, drug-intervened, cytokine-induced, and other-derived (liver-derived amp; spleen-derived) DCs. The results showed that all types of Tol-DC can effectively prolong graft survival, and the average extension of graft survival time for each group was as follows: 22.02 ± 21.9 days (3.2 folds to control group) in the gene modified group, 25.94 ± 16.9 days (4.3 folds) in the drug-intervened groups, 9.00 ± 8.13 days (1.9 folds) in the cytokine-induced group, and 10.69 ± 9.94 days (2.1 folds) in the other-derived group. The main mechanisms of Tol-DCs to prolong graft survival were as follows: a) induceT-cell hyporeactivity (detected by MLR); b) reduce the effect of cytotoxic lymphocyte (CTL); c) promote Th2 differentiation; d) induce Treg; e) induce chimerism. Conclusion For fully MHC mismatched allogeneic heart transplant recipients of inbred mouse, adoptive transfusion of Tol-DC, which can be gene-modified, drug-intervened, cytokine-induced, spleen-derived or liver-derived, can clearly prolong the survival of cardiac allograft or induce immune tolerance. Gene-modified and drug-induced Tol-DC can prolong graft survival most obviously. Having better reliability and stability than drug-induction, gene-modification is the best way to induce Tol-DCs at present. One-time intravenous infusion of 2 × 106 Tol-DC is a simple and feasible way to induce long-term graft survival. Multiple infusions will prolong it but increase the risk and cost. Adoptive transfusion of Tol-DC in conjunction with immunosuppressive agents may also prolong the graft survival time.
To study the expression of CTLA4Ig gene in diabetic rat and the effect of CTLA4Ig on longterm survival of the pancreatic islet. The rat pancreatic islet cell and muscle cell transfected with the cDNA for CTLA4Ig packaged with lipofectin vector. We examined the expression level of CTLA4Ig gene, T lymphocyte reaction and observed the expression of CTLA4Ig cDNA in diabetic rat and the action of CTLA4Ig in longterm survival of pancreatic islet transplanted and the transplanted rats. Results: The T lymphocyte reaction from peripheral intravenous blood at seventh day after surgery, the difference between two group was significant (Ｐ＜0.05). Only 2 out of 10 recipients of the experiment group (A) at the seventh day after pancreatic islet allograft had any detectable levels of CTLA4Ig, their concentration was 14 ng/ml, and 31 ng/ml. The average time of maintaining blood glycose in normal levels of the group A after pancreatic islets graft, 14.8±12.3 days, was significantly longer than 3.6±5.1 days of the control group (B) (Ｐ＜0.05). The average survival time of the group A, 24.0±10.8 days (the longest time was 45 days), was significantly longer than 11.8±4.8 days (the longest time was 21 days) of the group B (Ｐ＜0.01). Conclusions: The muclse cells and pancreatic islets of the recipient rat was transfected with CTLA4IgcDNA packaged with lipofectin, and CTLA4IgcDNA was expressed in recipient tissue, its expressed product CTLA4Ig make pancreatic islets transplanted and recipient rat survive longer significantly.
In order to reduce the immunogenicity of parathyroid allografts and induce immunotolerance, we depleted Ⅰa＋ donor cells of rat parathyroid allografts by anti-Ⅰa monoclonal antibody plus complement, transplanted the treated glands underneath the capsule of the recipient kindey,and observed the median survival time (MST) of the allografts. Our results showed that the MST of the treated group were 60 days, compared with control group (MST:14 days), Ｐ＜0.01. This results indicate that rat parathyroid allografts survival can be prolonged dramatically by depletion of Ⅰa＋ donor cells.
Abstract: Objective To investigate the influence of cryopreservation on cellular viability of latepregnancy fetal valved allografts in human. Methods The fetal valved allografts with gestational ages ranged from 24 to 40 weeks were sterilely procured within 6 hours after brain death. Each sample was bisected into control group and experiment group. The cellular viability of control group was directly tested and that of experiment group was examined after being storaged in liquid nitrogen for a week through a programmed frozen procedure. The light microscopy, tissue culture and Methylthiazol tetrazolium assay (MTT assay) were used to determine the cellular viability. Results Twelve latepregnancy fetal valved aortic allografts were procured. Light microscopy showed the integrity of the basic structure of the thawed aorta, the normal structure of the collagen and elastic fibers, with part of vascular endothelium lost. There were lots of cells deriving from both groups,but the cellular growing rate of the experiment group was relatively slower. At 490 nm, MTT assay valve of control group was 0.442±0.046, and that of experiment group was 0.424±0.041. The difference between two groups failed to statistically significance(t=1.617, P=0.328). Conclusion There were viable cells in latepregnancy fetal valved allografts after cryopreservation.
Objective To investigate the rat model of cardiac allograft vasculopathy after heart transplantation in rat abdominal cavity. Methods Forty Wistar rats and 40SDrats were divided into control group and experiment group randomly pair-matching. Rat model ofheterotopic heart transplantation was developed. Low doseCyclosporine A were injected into the abdominal cavity in experiment group, while the control group had not received the Cyclosporine A. Transplant hearts were harvested at two weeks and four weeks post-operatively and changes of coronary artery were observed by light microscope. Results There were no alteration of tunica intima of coronary artery in control group at two weeks and four weeks post-transplantation. Tunica intima of coronary artery increased in thickness at two weeks post-transplantation in experiment group and concentric circular change occurred at four weeks post-transplantation. Lumen of coronary artery constricted transparent and cardiac allograft vasculopathy occurred. Conclusion This animal model is reliable of cardiac allograft vasculopathy.
【Abstract】 Objective To investigate the protective effect of early motion on articular cartilage after joint allograft by performing a controlled trial between different post-operation strategies after joint allograft in an animal model. Methods Twenty hemi-knee joints were harvested from 10 6-month-old New Zealand white rabbits (male or female, weighing 2.5-3.0 kg); 10 hemi-knee joints by deep frozen treatment (donors) were transplanted to unilateral knee joints (recipients) of 10 6-month-old Chinchilla rabbits (male or female, weighing 2.5-3.0 kg), which were divided into early motion group (n=5) and sustained fixation group (n=5); and 10 hemi-knee joints were used as blank control (n=5) and frozen control (n=5). The articular cartilage of allogenic joints was detected by X-ray film, gross, and histology at 6 weeks after operation. Results Gross observation: no obvious limitation of joint movements was observed in early motion group, but obvious limitation in sustained fixation group. X-ray films: the bone ends between donor and recipient healed well with good paraposition and alignment on the operation day and 2 weeks after operation; at 6 weeks, angulation deformity was observed in early motion group of 3 rabbits, and paraposition and alignment were satisfactory in sustained fixation group. Histological observation: HE staining showed that the chondrocytes had normal quantity and morphology with few nuclear fragmentation and karyolysis in early motion group, but the quantity of chondrocytes sharply decreased with dissolved nuclei and numerous fibrous tissues in the cartilage matrix in sustained fixation group. The cell survival rate of the early motion group (49.66% ± 2.15%) was significantly higher than that of the sustained fixation group (20.68% ± 1.24%) (P lt; 0.05). Scanning electron microscopy observation: nuclear membrane was intact with chromatin condensation and edema of mitochondria and rough surfaced endoplasmic reticulum in early motion group, and that the membrane of chondrocyte vanished with blurring border between chondrocyte and matrix, rupture of nuclear membrane and the disappearance of chromatin and organelles could be found in sustained fixation group. Conclusion Early motion has protective effect on articular cartilage after joint allograft, but cannot completely prevent degeneration of the allogenic articular cartilage.
Objective To find out the recent progress in research of cl inical appl ication of fascia lata allograft. Methods The domestic and international articles were reviewed to summarize the princi pal properties, processing techniques, and various uses of fascia lata allograft. Results Histologically fascia lata is composed of parallel and compact bundles of collagen fibers with few cells and immunologically it is low-antigenic. After varied tissue processing and storage techniques, fascia lata, as the scaffold only with the extracellular matrix, has been used in cl inical practice and achieved good results, such as ophthalmology, urology, and orthopaedics. Conclusion Because of these unique properites in repairing defects and reconstructing functions, fascia lata allograft, as a natural biomaterial, is promising to be used in more aspects withthe development of the biomedical techniques.
Objective To study the effectiveness of anterior cruciate l igament (ACL) reconstruction using autologous periosteum wrapping tendon allograft by comparing with using simple tendon allograft. Methods Between March 2008 and November 2008, 68 patients with ACL injury were treated, who were in accordance with the inclusion criteria. They were divided into 2 groups randomly according to different treatment methods: ACL was reconstructed with autologous periosteum wrapping tendon allograft in 31 patients (test group) and with simple tendon allograft (control group) in 37 patients. There was no significant difference in gender, age, disease duration, the cause of injury, and functional score preoperatively between 2 groups (P gt; 0.05). Anatomic single-bundle ACL reconstruction was performed in 2 groups. Results Little exudation at tibial tunnel incision was found in 1 case respectively in both groups at 2 weeks after operation and was cured by dressing change and antibiotics. The other incisions healed by first intention. The patients were followed up 24-29 months (mean, 26 months) in the test group and 24-32 months (mean, 27 months) in the control group. CT showed bone tunnel enlargement in both groups at 2 years after operation, but the rate of the tunnel enlargement was less inthe test group (5/31, 16.1%) than in the control group (14/37, 37.8%), showing significant difference (χ2=3.948, P=0.047). At 2 years after operation, the results of Lachman test and pivot shift test were negative in 23 cases (74.2%) and 25 cases (80.6%) of the test group, and in 26 cases (70.3%) and 30 cases (81.1%) of the control group, respectively. KT-1000 examination showed the displacement of the test group [(1.74 ± 0.88) mm] was less than that of the control group [(2.36 ± 0.83) mm], showing significant difference (t= —2.979, P=0.004). There was no significant difference in Lysholm score, Hospital for Special Surgery (HSS) score, Tegner score, and International Knee Documentation Committee (IKDC) score between 2 groups at 2 years after operation (P gt; 0.05). Conclusion Compared with simple tendon allograft, ACL reconstruction with autologous periosteum wrapping tendon allograft can improve tendon-bone heal ing, and decrease the rate of bone tunnel enlargement, so it has good short-term outcome.
Objective To observe the changes of force bearing area and pressures of the rabbit tibiofemoral contact area and the biomechanical reconstruction level of joint after meniscal allograft. Methods A total of 28 Japanese rabbits were involved, weighing 3.0-3.5 kg, male or female. Of 28 rabbits, 7 were selected as meniscus donors, the remaining 21 rabbits were randomized into group A (n=7), group B (n=7), and group C (n=7). Group A underwent single knee opening and suturing, group B underwent medial meniscus excision and suturing, and group C underwent medial meniscus allograft after medial meniscus excision and suturing. The rabbits were sacrified at 12 weeks after operation for biomechanical observation through biomechanical machine and color imaging system. The meniscus tissue specimens were harvested from groups A and C to perform histological and immunohistochemical staining. Results After operation, all rabbits in 3 groups survived to the end of experiment. There were significant differences in the force bearing area and pressures at 0-90° flexion between group B and groups A, C (P lt; 0.05) at 12 weeks, showing no significant difference between group A and group C (P gt; 0.05); and there were significant differences in the force bearing area and pressures at 120° flexion among 3 groups (P lt; 0.05). The histological observation showed that the number of cartilage cells and collagen fibers returned to normal in group C, and the immunohistochemical staining showed that transplanted meniscus of group C contained large amounts of collagen fibers consisting of collagen type I and collagen type II. After 12 weeks of operation, the collagen type I contents were 0.612 5 ± 0.059 8 in group A and 0.587 2 ± 0.063 9 in group C, showing no significant difference (t=0.765, P=0.465); the collagen type II contents were 0.772 4 ± 0.081 5 and 0.814 3 ± 0.051 7, respectively, showing no significant difference (t= —0.136, P=0.894). Conclusion The allograft of rabbit meniscus can significantly increase the force bearing area of the tibiofemoral contact area and reduce the average pressure. Therefore, biomechanically speaking, the meniscus allograft can protect the articular cartilage and reconstruct the biomechanical balance.
Objective To observe the long-term effectiveness of tendon allograft to repair tendon defect. Methods Between October 1996 and September 1999, 24 patients with tendon defect were treated with tendon allograft which was cultured with deoxyguanosine and preserved at low-temperature or ultra-deep-low-temperature. There were 19 males and 5 females, aged from 12 to 46 years with an average of 25.9 years. These patients included 7 cases of total extensor tendon defect of 2nd-5th fingers, 7 cases of index finger extensor tendon defect, 3 cases of deep flexor tendon defect of 2nd- 5th fingers, 1 case of ring finger deep flexor tendon defect, 3 cases of long extensor tendon defect of 2nd-5th toes, 2 cases of long extensor hallucis tendon defect, and 1 case of shoulder adduction missing. The sizes of tendon defect ranged from 5 to 15 cm. The mean time from injury to operation was 1.3 months (range, 2 hours to 3 months). Results Incisions healed by first intention. No deep infection, infectious diseases, and obvious immune rejection occurred. All patients were followed up from 10 to 12 years with an average of 10.8 years. When compared with contralateral sides, at 10 years of follow-up, 1 patient lost 6-10° flexion function; after 10.6 years, flexion tendon releasing was performed; allografted tendon had normal color and elasticity with decreased diameter and with mild and moderate adherence; and after releasing, function was improved. According to Hand Surgery Association assessment standard, the results were excellent in 12 cases, good in 6, and poor in 6; the excellent and good rate was 75%. Conclusion Tendon allograft which is cultured with deoxyguanosine and preserved at low-temperature or ultra-deep-low-temperature is safe to use in cl inical, which has good long-term effectiveness in treating tendon defect.