气管移植的研究进展

气管移植目前仍处于动物实验阶段，影响气管移植应用主要因素在于移植气管的再血管化、有效的免疫抑制及供者气管的保存、带蒂大网膜包裹移植 管是移植体再血管化的有效方法。先期将气管移植体置于大网膜内，再将带蒂大网膜气管移植能明显提高移植体的再血管化，并降低移植体的感染率，气管的再血管化仍受到气管移植长度的限制，为解决这一问题，近年利用分段气管移植能有效延长气管移植开度，动物实验表明，气楠样存在移植排斥反应     

The effect of basic fibroblast growth factor and omentopexy on revascularization and epithelial regeneration of heterotopic rat tracheal isografts.

Donor airway ischemia is a significant problem after clinical lung transplantation despite the use of omentopexy for accelerated local bronchial revascularization. Several growth factors have been shown to induce angiogenesis in vitro and in vivo. In the present study the quantitative effects on tracheal revascularization and epithelial regeneration of omentopexy and continuous local administration of basic fibroblast growth factor were investigated in a heterotopic rat tracheal isograft model. Tracheas were harvested from donor rats and heterotopically implanted into the omentum of syngeneic recipient rats. Animals were randomly assigned to study groups differing only in treatment of the tracheal segments: omental wrap for 2, 7, or 14 days; omental wrap plus continuous local administration of basic fibroblast growth factor for 7 or 14 days; or omental wrap plus local application of saline for 7 or 14 days. Two, 7, or 14 days after the animals were put to death, the vascularity of the tracheal segments and attached omentum and the tracheal epithelial morphology were assessed in a blinded fashion with use of light microscopy and morphometric image analysis. Vascularity in tracheal segments treated with basic fibroblast growth factor was significantly (p less than 0.05) greater than in control tracheas after 7 and 14 days. Epithelial regeneration was also improved in the basic fibroblast growth factor-treated groups at days 7 and 14 (p less than 0.05). We conclude that continuous local administration of basic fibroblast growth factor enhances early revascularization of tracheal segments induced by omentopexy and accelerates epithelial regeneration in a heterotopic rat tracheal isograft model.     

Short-course immunosuppression using FK506 for rat tracheal allografts

BACKGROUND: A minimizing immunosuppression after a tracheal allotransplantation is desirable. METHODS: We examined the usefulness of a short-course of immunosuppression after tracheal allotransplantation in rat. Each transplant consisting of a 5-ring segment was heterotopically implanted into the omentum. Four animals underwent a syngeneic transplantation and thus served as controls (Group A). Thirty animals underwent an allogeneic transplantation and were randomly classified into 4 groups as follows: No immunosuppression (Group B, n=6), treatment with 0.5 mg/kg of Tacrolims (FK506) (Group C, n=8), 1.0 mg/kg of FK506 (Group D, n=8), and 1.5 mg/kg of FK506 (Group E, n=8). Different doses of FK506 were administered intramuscularly for only three consecutive days after heterotopic tracheal allotransplantation. The serum levels of FK506 were then investigated 3, 7, 14, 21, and 28 days after transplantation in groups C, D, and E. All rats were killed 28 days after transplantation and then the implanted tracheae were harvested, and evaluated histologically. RESULTS: All animals survived for the protocol period. The graft morphology of Group E was significantly better than that of groups B, C, and D regarding both macro- and microscopy, and also showed the same findings as that of Group A, except for low-grade mononuclear cell infiltration. Only in Group E, the FK506 blood level was maintained at over 0.5 ng/ml, which is the lowest detectable limit in this assay, until 21 days after transplantation. CONCLUSIONS: We thus conclude that 1.5 mg/kg of FK506 which was administered for only three consecutive days after surgery may be used to maintain the morphology of tracheal allografts in rats for 28 days after transplantation.     

Learning Curve in Tracheal Allotransplantation

The first vascularized tracheal allotransplantation was performed in 2008. Immunosuppression was stopped after forearm implantation and grafting of the recipient mucosa to the internal site of the transplant. Nine months after forearm implantation, the allograft was transplanted to the tracheal defect on the radial blood vessels. Since then, four additional patients have undergone tracheal allotransplantation, three (patients 2–4) for long‐segment stenosis and one (patient 5) for a low‐grade chondrosarcoma. Our goal was to reduce the time between forearm implantation and orthotopic transplantation and to determine a protocol for safe withdrawal of immunosuppressive therapy. Following forearm implantation, all transplants became fully revascularized over 2 months. Withdrawal of immunosuppression began 4 months after graft implantation and was completed within 6 weeks in cases 2–4. Repopulation of the mucosal lining by recipient cells, to compensate for the necrosis of the donor mucosa, was not complete. This resulted in partial loss of the allotransplant in patients 2–4. In patient 5, additional measures promoting recipient cell repopulation were made. The trachea may be used as a composite tissue allotransplant after heterotopic revascularization in the forearm. Measures to maximize recipient cell repopulation may be important in maintaining the viability of the transplant after cessation of immunosuppression.     

CTLA4Ig-gene transfection inhibits obliterative airway disease in rats

BACKGROUND: Obliterative airway disease (OAD) is a major cause of long-term morbidity following lung transplantation. Its pathologic characteristics are small-airway inflammation and occlusion by fibrous tissue. However, the pathogenesis is uncertain and therapy is ineffective. This study presents the effects of CTLA4Ig-gene therapy on OAD in heterotopically transplanted rat tracheal allografts. METHODS: Dark Agouti (DA, RT1a) allografts and Lewis (LEW, RT1l) isografts were transplanted into Lewis recipients. The tracheal graft was transplanted heterotopically into the subcutaneous pocket into the back. Adenoviral vectors (1.0x10(9) pfu) containing the CTLA4Ig-gene (AdCTLA4Ig) or the LacZ-gene (AdLacZ) were injected into the tail vein immediately after grafting. Grafts were harvested and examined after more than 35 days for mononuclear cell infiltration development and lumen occlusion with fibrosis. RESULTS: Fully allogenic DA tracheas, treated with AdCTLA4Ig had significantly lower pathologic scores and infiltrating scores than the control allografts. The pathologic findings of the grafts, treated with AdCTLA4Ig, were very similar to those of the syngeneic grafts. The animals experienced no adverse events during follow-up. No evidence of vector-mediated tissue damage was seen in any graft. CONCLUSIONS: Adenoviral vectors containing the CTLA4Ig-gene markedly inhibited the obliteration of the airway lumen. OAD may be associated with T-cell responses against graft tissue and alloimmune injury.     

Long-term tolerance to kidney allografts in a preclinical canine model

Durable immune tolerance supporting vascularized allotransplantation offers the possibility of extending graft survival and avoiding harmful complications of chronic immunosuppression. Immune tolerance to renal allografts was induced in a preclinical canine model through engraftment of donor hematopoietic cells using a combination of low-dose total body irradiation and a short course of immunosuppression. Subsequently, donor renal allografts were transplanted accompanied by bilateral native nephrectomies. With 5-year follow up, we found normal renal function in all recipients and no histological evidence of acute or chronic rejection. This tolerance does not extend universally to donor skin grafts, however, with two of four animals rejecting delayed donor skin grafts. Hematopoietic chimerism produces durable and robust immune tolerance to kidney allografts, although incomplete tolerance to donor skin grafting.     

Use of older donor livers is associated with more extensive ischemic damage on intraoperative biopsies during liver transplantation.

Initial poor graft function is associated with increased morbidity and graft loss after liver transplantation. Donor age is a risk factor for the development of initial poor function. The severity of ischemic damage on intraoperative postreperfusion (0Post) allograft biopsy specimens is predictive of subsequent initial poor function. This study was performed to assess whether donor age is a risk factor for the development of ischemic damage on 0Post biopsy specimens. The records of 94 liver transplantations were reviewed. 0Post biopsy specimens were obtained after complete allograft revascularization. The severity of ischemic damage was graded as follows: 0, none; 1, minimal; 2, mild; 3, moderate; and 4, severe. Grafts were defined as older when donor age was 50 years or older. Other independent variables examined included donor cause of death, length of hospital stay, acidosis, serum alanine aminotransferase level, graft cold ischemia time, and degree of steatosis. Older grafts were associated with higher grades of ischemic damage than younger grafts (2.3 +/- 1.0 v 1.3 +/- 1.1; P =.003). Univariate and multivariate analysis identified donor age of 50 years or older as the only significant predictive variable of the severity of ischemic damage. In 16 transplantations involving older grafts, there was no statistically significant association between the severity of ischemic damage and incidence of initial poor function and graft loss. The use of older liver grafts is associated with more extensive ischemic damage immediately after graft reperfusion. Whether this early lesion identifies among older graft recipients those at risk for a worst outcome remains to be determined.     

Immunosuppressive effect of combination schedules of brequinar with leflunomide or tacrolimus on rat cardiac allotransplantation

Drug toxicity is one of the major problems in clinical immunosuppression. Combining two immunosuppressants in low or ineffective doses is an attractive strategy if it helps to reduce drug-related toxicity. We examined the immunosuppressive efficacy of brequinar (BQR) in combination with leflunomide (Lef) or tacrolimus (FK) in a heterotopic rat cardiac allotransplantation model. Abdominal heterotopic heart grafts (DA x LEW) were immunosuppressed from the time of transplantation and continued until the ninth posttransplant day (POD) in experiments examining prophylaxis of rejection treatment (PRT). In a separate series of experiments designed to test rescue treatment (RT), immunosuppression was begun on POD 4 and continued for 10 days; transplanted rats were sacrificed the following day intentionally. Cardiac rejection was monitored by palpation and documented by light microscopy. Immunosuppressive drugs (BQR 3 mg/kg and 12 mg/kg; BQR 3 mg/kg + Lef 5 mg/kg; BQR 3 mg/kg + FK 0.5 mg/kg) were given orally by gavage; thrice weekly according to the monotherapy or dual-therapy dosing protocol. Median survival time of the cardiac graft for controls (no treatment) was 5 days. BQR monotherapy 3 mg/kg (low dose) improved graft survival (P = 0.003); graft histology showed moderate acute rejection. BQR monotherapy 12 mg/kg (therapeutic dose) application in the PRT or RT treatment arms of the study design resulted in aortic-graft ruptures and clinical toxicity in each treatment arm due to overimmunosuppression; normal graft morphology was maintained. Successful rescue of rejecting grafts was histologically documented. Combining BQR with Lef or FK in the PRT protocol showed prolonged graft survival in both drug combination groups (median survival time, 14 days; P = 0.009 and 0.014, respectively). Using an identical combination protocol for RT, all grafts achieved a 14-day graft survival; cardiac histology showed reversible moderate acute rejection. BQR given in the presence of Lef or FK not only prevented acute rejection but intercepted it so long as it was administered; grafts were rejected within 4 days of stopping immunosuppression in the PRT study. These combinations using low or subtherapeutic doses may be important for controlling transplant rejection and rescuing ongoing graft rejection. The need for continuing treatment in this strongly allogeneic model is highlighted.     

Reepithelialized orthotopic tracheal allografts expand memory cytotoxic T lymphocytes but show no evidence of chronic rejection

BACKGROUND: Acute rejection of mouse tracheal allografts is characterized by infiltration of the lamina propria with CD4+/CD8+ T cells that leads to the destruction of the epithelium and luminal obliteration. The donor epithelium is progressively replaced by recipient-derived epithelium. Once allograft reepithelialization has occurred, immunosuppression can be withdrawn without inciting acute rejection. We hypothesize that reepithelialization will also prevent chronic rejection of the trachea after withdrawal of immunosuppression. METHODS: BALB/c tracheal grafts were transplanted orthotopically into allogeneic C57BL/6 recipients. Allografted mice were nonimmunosuppressed for 10 or 100 days or immunosuppressed with cyclosporine A continuously for 50 days and then withdrawn from immunosuppression for an additional 50 days. In addition, grafts from this group were then heterotopically retransplanted into isogenic C57BL/6 or allogeneic BALB/c recipients to assess their immunogenicity. RESULTS: Cyclosporine A-treated mice showed no signs of chronic rejection or priming of cellular immunity as measured by proliferation and cytokine secretion in a mixed leukocyte reaction. However, there was a notable expansion of memory CD8+ T cells specific for donor major histocompatibility complex. When these tracheal allografts were retransplanted heterotopically into C57BL/6 or BALB/c, they demonstrated reduced responses toward BALB/c and primed responses toward C57BL/6, respectively. These results suggest that the grafts express a chimeric phenotype consisting of both BALB/c and C57BL/6 antigens. CONCLUSION: These observations suggest that long-term withdrawal of immunosuppression does not lead to chronic tracheal rejection even in the presence of alloantigen specific cytotoxic T-lymphocyte responses and that the reepithelialized grafts may contain donor elements that impact the generation of immunity.     

Cardiac xenotransplantation in primates

Successful cardiac xenotransplantation would alleviate the severe shortage of donor organs that presently limits the availability of cardiac transplantation. Early attempts at human xenotransplantation achieved minimal success. However, the effectiveness of cyclosporine in nonhuman xenotransplant models has received little experimental investigation. We have therefore studied the effect of cyclosporine-based immunosuppression in primate cardiac xenograft models using cynomolgus monkey donors and baboon recipients. Donor hearts were transplanted heterotopically into the necks of recipients or in the orthotopic position. Recipients were treated with no immunosuppression (controls), cyclosporine and steroids, or cyclosporine, steroids, azathioprine, and antithymocyte globulin. Statistically significant prolongation of graft survival compared to the control group was observed in the heterotopic groups. Mean survival time of the cyclosporine-treated and steroid-treated heterotopic grafts was 61 days compared to 6 days for grafts in the control group (p = 0.01); the addition of azathioprine and antithymocyte globulin yielded a mean survival of 84 days (p less than 0.01). No significant increase in graft survival was noted in the orthotopic groups treated with either immunosuppressive regimen. Although long-term use of human xenografts as an alternative for heart replacement is not supported by these data, further investigation of the orthotopic model is clearly justified.     

Riboflavin-mediated reduction of oxidant injury, rejection, and vasculopathy after cardiac allotransplantation

BACKGROUND: Riboflavin is a well-known nutritional supplement that has been shown to exhibit antioxidant properties and protect tissue from oxidative damage. We hypothesized that riboflavin given during cardiac ischemia-reperfusion (I/R) might reduce subsequent acute rejection, after allotransplantation, and coronary allograft vasculopathy (CAV). METHODS: A murine heterotopic cardiac transplantation model was used to test whether riboflavin improves I/R injury and acute/chronic rejection. RESULTS: Riboflavin significantly reduced oxidant production and inflammatory mediator production induced by I/R injury, as evidenced by decreased levels of malondialdehyde, myeloperoxidase activity, and tumor necrosis factor alpha. Administration of riboflavin also improved graft survival and suppressed T-cell infiltration and donor-reactive alloantibody formation during the early period after allotransplantation. A murine long-term cardiac allograft model using immunosuppression (preoperative anti-murine CD4 and anti-CD8) was employed to investigate the effect of riboflavin against CAV at 60 days. Riboflavin-treated grafts exhibited a significant decrease in the severity of coronary artery luminal occlusion as compared with saline-treated grafts (17.4+/-1.8% vs. 43.5+/-5.6%, P=0.0012). However, there was no significant effect of riboflavin to reduce donor-reactive alloantibodies in this chronic model. CONCLUSIONS: These data indicate that riboflavin improves early I/R injury and reduces the development of CAV, most likely due to alloantigen-independent effects such as reduced early graft oxidant stress. Riboflavin administered in the setting of cardiac allograft transplantation appears to be a powerful means to reduce early graft lipid peroxidation, leukocytic infiltration, and cytokine production as well as to suppress the late development of cardiac allograft vasculopathy.     

Split tolerance to a composite tissue allograft in a swine model

BACKGROUND: The antigenicity of skin is a major obstacle to expanding human composite tissue transplantation. For example, multiple rejection episodes of the skin have been noted in clinical hand transplant patients. We have previously demonstrated tolerance to vascularized musculoskeletal allografts in major histocompatibility complex (MHC)-matched miniature swine treated with 12 days of cyclosporine. This regimen did not reproducibly lead to tolerance to subsequent frozen donor skin grafts. However, such skin grafts did not have a primary vascular supply. The aim of this study was to determine if tolerance to limb allografts with a vascularized skin component could be achieved with MHC matching and a 12-day course of immunosuppression. METHODS: Hind limb grafts harvested with a 100 cm(2) cutaneous paddle were transplanted heterotopically into six MHC-matched, minor antigen-mismatched miniature swine. All animals received a 12-day course of cyclosporine. One control animal was not immunosuppressed. Grafts were evaluated with biweekly biopsies and tissue viability determined by histologic analysis. To test for sensitization, frozen donor skin grafts were applied to all animals that survived to postoperative day 100. RESULTS: All treated animals (n=6) were tolerant to their musculoskeletal allografts at the time of necropsy (>100 days) regardless of the status of the epidermis. One animal demonstrated tolerance to the skin for more than 180 days. The other five animals demonstrated prolonged survival of the epidermal portion of the graft. The control animal rejected the graft epidermis at 10 days postoperatively. Frozen donor skin grafts demonstrated accelerated rejection (<10 days) in three of the animals and led to simultaneous rejection of both the epidermis of the allograft and the skin graft in the long-term tolerant animal. The rejection of the skin grafts did not break tolerance to the musculoskeletal portion in any of the animals. CONCLUSIONS: All animals exhibited indefinite survival of the musculoskeletal portion of their allografts but only prolonged survival of the epidermis. The loss of the graft skin appears to be the result of an isolated immune reaction to the skin, and, in particular, the epidermis. This observation is further substantiated by the accelerated rejection of secondarily placed frozen donor skin grafts.     

Simplified techniques in rat heterotopic small bowel transplantation

AIM: Establish a simplified heterotopic small bowel transplantation (SBT) in the rat. METHODS: Ninety pairs of male Wistar rats were used as donors and recipients. The whole small intestine with a vascular pedicle composed of superior mesenteric artery (SMA) and portal vein (PV) was harvested as the graft. Revascularization was accomplished by end-to-side anastomosis between donor SMA and recipient infrarenal aorta and cuffed end-to-end anastomosis between donor PV and left renal vein of recipient. The distal end of graft was exteriorized to form an enterostoma. RESULTS: Average time of an operation was 130 minutes and the mean warm ischemia time of grafts was 30 minutes. The technical success rate of this model was 100% and 7-day survival was 95.6% (86/90). CONCLUSION: This simplified technique was effective and practical to improve the outcome of rat heterotopic SBT.     

Experimental tracheal reconstruction by allotransplantation

Reconstruction using allotransplantation was successfully performed for large defects of the trachea. The defects of ten tracheal rings were surgically created in 28 mongrel dogs and they were repaired with allografts of 5 rings, using over-and-over continuous suture technique with 4-0 Prolene. After the completion of anastomosis, omental pedicle was used to wrap the allograft including both the ends of the graft. Immunosuppressant FR900506 (FK506) was daily administered with a dose of 0.1 mg/kg body weight intramuscularly. When the dogs were sacrificed or succumbed, all the grafts were excised and were examined microscopically and scanning electron microscopically. In some of them, the revascularization from the omental pedicle was examined by infusion of Indian ink from the feeding artery. Eleven dogs survived for more than 30 days and 3 of them did over 120 days. The longest survival is 202 days and the dog is now alive. Twenty out of the 28 allografts were proved to be viable with normal tracheal structure and also free of granulation or stricture. One dog died of perforation of the graft due to rejection. Another dog succumbed from other disease, but the graft was necrotized without the sign of rejection. The viability of the grafts of the remaining 6 dogs were not determined, because the survival time were not long enough, although the grafts were intact macroscopically and microscopically. Three or four weeks after transplantation, the surface of the graft was covered with ciliated epithelium and the tracheal architects were almost normalized. It was proved that revascularization of the tracheal graft from the omental pedicle was established within 7 days following the operation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cardiac xenotransplantation: recent preclinical progress with 3-month median survival

OBJECTIVES: Transplantation is limited by a lack of human organ donors. Organs derived from animals, most likely the pig, represent a potential solution to this problem. For the heart, 90-day median graft survival of life-supporting pig hearts transplanted to nonhuman primates has been considered a reasonable standard for entry into the clinical arena. Overcoming the immune barrier to successful cardiac xenotransplantation is most appropriately first explored with the non-life-supporting heterotopic model. METHODS: We performed a series of 7 heterotopic heart transplantations from CD46 transgenic pigs to baboons using a combination of therapeutic agents largely targeted at controlling the synthesis of anti-pig antibodies. Rituximab (anti-CD20) and Thymoglobulin (rabbit antithymocyte globulin [ATG]; SangStat Medical Corp, Fremont, Calif) were used as induction therapy. Baseline immunosuppression consisted of splenectomy, tacrolimus, sirolimus, steroids, and TPC (an anti-Gal antibody therapeutic). Rejection events were not treated. RESULTS: By using Kaplan-Meier analysis, median graft survival was 96 days (range, 15-137 days; 95% confidence interval, 38-99 days). Only 2 grafts were lost as a result of rejection, as defined by cessation of graft palpation. There was no evidence of a consumptive coagulopathy, infectious complications were treatable, and no posttransplantation lymphoproliferative disorders occurred. No cellular infiltration was observed. CONCLUSIONS: This study reports the longest median survival to date (96 days) of pig hearts transplanted heterotopically into baboons. Duplication of these results in the orthotopic life-supporting position could bring cardiac xenotransplantation to the threshold of clinical application.     

Carcinogenesis in canine bistomal heterotopic tracheal grafts

Successful canine lung cancer models have required repeated focal bronchial carcinogen exposure under general anesthesia. To simplify serial studies of the respiratory mucosa during carcinogenesis, bistomal autologous heterotopic tracheal pedicle grafts have been made. These grafts can readily be returned to the original orthotopic site, and this has been shown to be a method with which to study reversibility of mucosal changes. Polycyclic aromatic hydrocarbons were applied topically to the mucosa three times a week for 21 to 22 months in 21 grafts. Implants of Silastic polymer from which carcinogen was released in sustained-release fashion were then left in the grafts for 4 to 6 weeks. Serial cytological and histological examinations showed development of atypical squamous metaplasia in the graft mucosa. Mucosal papillomatosis was noted in 4 of 7 grafts surgically excised 17 to 18 months after completion of carcinogen exposure. The heterotopic bistomal tracheal graft provides a useful method for studying respiratory epithelial carcinogenesis without repeated general anesthesia.     

Factors influencing clinical outcomes after revascularization in the asymptomatic cardiac ischemia pilot (ACIP). ACIP Study Group

BACKGROUND AND AIM: The Asymptomatic Cardiac Ischemia Pilot is the first randomized trial where revascularization involved choice of either coronary bypass or angioplasty used in an early or a delayed symptom-driven approach. One-year outcomes were favorable (reduced recurrent ischemia and adverse outcomes) for an early revascularization strategy (within 4 weeks), compared with an early medical strategy when revascularization was delayed until symptom-driven. This ancillary study examined variables influencing outcomes after these 2 revascularization approaches (early vs. delayed until symptom-driven). METHODS: Participants were clinically stable coronary disease patients with stress-induced and daily life ischemia who underwent revascularization. Characteristics associated with clinical outcomes occurring within the year following revascularization were examined using Cox regression analysis. RESULTS: A total of 262 patients received revascularization; 170 in the early approach and 92 in the delayed symptom-driven approach. Thirty-three patients had adverse outcomes (death, nonfatal myocardial infarction, or repeat revascularization) during 1-year follow-up. The most important independent predictor of improved outcome during the follow-up year was attempted revascularization of > or = 66% of vessels with significant stenosis for the early (risk ratio [RR] 0.25, 95% confidence interval [CI] 0.09-0.67) and the delayed (RR 0.21, CI 0.08-0.58) approaches. Factors such as age, stress test results, and coronary angiographic findings did not predict clinical outcome. CONCLUSIONS: Our findings are important in the planning of a large trial with longer follow-up.     

Evaluation of renal grafts in patients with lupus nephritis as cause of end-stage renal disease

INTRODUCTION: Kidney transplantation is the best option in end-stage renal disease (ESRD). For many years patients affected with lupus nephritis have had poor graft results. However, this has been changing over recent years with the development of new immunosuppressive drugs and a better comprehension of the natural evolution of the entity. METHODS: We studied 20 patients with lupus nephritis who received 22 kidney grafts: 15 women and five men (n = 11) who were treated with cyclosporine or with tacrolimus (n = 11). Secondary immunosuppression included mycophenolate match (MMF) (n = 13) or azathioprine (n = 9). We analyzed human leukocyte antigen, cold ischemia time, acute tubular necrosis, creatinine, cholesterol, triglycerides, glucose, blood pressure, acute rejection episodes, immunosuppression, infections, disease recurrences, as well as graft and patient survival. RESULTS: After a mean cold ischemia time of 22 +/- 4 hours, nine patients displayed delayed graft function of an average duration 9 +/- 4 days. At 36 +/- 35 months nine grafts were lost: two due to acute rejection; five to chronic allograft nephropathy; and two to venous thrombosis. One patient died of hemorrhagic shock. There were five cytomegalovirus infections. Graft survival was dependent on the type of secondary immunosuppression, incidence of acute rejection episodes and occurrence of delayed graft function. CONCLUSIONS: We found no clinical recurrence of lupus nephritis after transplantation and a low incidence of complications, although there was a trend toward thrombosis. The presence of delayed graft function, episodes of acute rejection, and receiving azathioprine instead of MMF as secondary immunosuppression were associated with poorer graft survival.     

Heterotopic hindlimb allotransplantation in rats: an alternative model for immunological research in composite-tissue allotransplantation

A nonfunctional heterotopic hindlimb allotransplantation model is presented, and a study was performed between this model and standard orthotopic hindlimb transplantation to compare operation and ischemia time, overall morbidity, and mortality rates. In this model, the skin component of the hindlimb was stripped away to the ankle level, and the remaining part along with the vascularized epigastric skin was transplanted heterotopically to the inguinal space of the recipient. No osteotomy and intramedullary fixation were performed. Thirty heterotopic and orthotopic hindlimb transplantations were performed in two groups. Each group involved 15 transplantations from inbred, male Brown Norway (BN; RT1n) weighing 150-200 g to Lewis rats (LEW; RT1(1)) weighing 250-300 g. The animals were followed up for 2 weeks under immunosuppression with cyclosporine A (16 mg/kg/day). Mean operation times for heterotopic and orthotopic hindlimb transplantations were 60 and 105 min, with ischemia times of 35 and 85 min, respectively. No animal deaths or major complications were encountered in heterotopic hindlimb transplantation during the follow-up period. Seroma formation was observed in one animal as the only minor complication. The mortality rate for orthotopic hindlimb transplantation was 26.7%, and there were minor complications in 35%, including infection, ulceration, and loss of rigid fixation. This model circumvents the disadvantages of osteotomy and intramedullary fixation, which may increase the risk of blood loss, embolus, and infection in immunosuppressed animals. It also helps avoid tension or kinking on the anastomosis due to inadequate judgment of the osteotomy level, distortion associated with loss of rigid fixation, and weight mismatch between donor and recipient. From the immunological point of view, insult to bone marrow is avoided, and a relatively constant amount of bone marrow is introduced to be used in chimerism-based tolerance studies. We recommend this model for composite-tissue allotransplantation studies when functional recovery is not of primary importance.