Failure of cyclosporine to prevent small bowel allograft rejection in pigs

The effect of cyclosporine (CyS) on survival and function of 250 cm intraabdominal heterotopic small bowel allografts was studied in outbred pigs. Experimental animals received oral CyS alone (25 mg/kg/day), or oral CyS, donor bowel radiation, and recipient splenectomy; controls were untreated. Excluding technical failures, no significant differences in graft survival were observed, although one relatively long-term survivor occurred in each treated group. Rejection was not related to cyclosporine levels. These data show that CyS as a single agent as well as when used with supplemental therapy does not uniformly prevent rejection of small bowel allografts in pigs, although an occasional long-term survivor will occur. The failure to achieve consistently successful engraftment may reflect the large quantity of lymphoid tissue in small bowel. Further experimentation is required before human transplantation is again attempted.     

Allogeneic fetal small bowel graft in pigs treated with cyclosporin A

BACKGROUND: The functional integrity of transplanted fetal intestine was proven in rodents. The authors examined the morphology and development of intraperitoneally transplanted fetal intestine under cyclosporin A (CsA) monotherapy in a large mammal. METHODS: Allogeneic fetal intestinal grafts were transplanted intraperitoneally in pigs. The graft was wrapped in omentum. Thirteen recipients received grafts harvested at 60 days of gestation and 5 at 105 days of gestation. All recipients received 25 mg/kg/d CsA. CsA blood levels were measured at the end of the study. The development of the grafts was assessed by inspection and histology studying revascularization, maturation, and immune rejection. RESULTS: All grafts developed neovascularization. The intestinal wall in the 105-day-old group was thick enough to lead to complete mucosal destruction, whereas the 60-day-old group showed viable mucosa. All grafts induced an immune rejection. This immune response was correlated with the CsA blood level. The graft was destroyed within 15 days when CsA trough level was below 70 ng/mL, had a subacute rejection with villi atrophy when CsA trough level ranged from 70 to 150 ng/mL, and had a good appearance in spite of mild blunting of villi when CsA trough level was over 150 ng/mL. CONCLUSION: Allogeneic fetal intestinal transplantation from 60-day-old embryos in pig achieved successful graft.     

Immunological advantage on small bowel graft induced by simultaneously transplanted liver in porcine auxiliary liver/small bowel transplantation

BACKGROUND: We developed a new porcine model for auxiliary liver/small bowel transplantation (LSBT). The possible immunological advantage on small bowel graft induced by simultaneously transplanted liver in the large animal was assessed. METHODS: Thirty outbreed long-white pigs were randomized into two groups. Group A animals received LSBT without immunosuppressive treatment (n = 10). Group B animals had segmental small bowel allotransplantation without immunosuppressive treatment (n = 10). The postoperative survival time, initial acute rejection time, and pathological rejection scores were analyzed. RESULTS: There was no remarkable difference in survival time between groups A and B (10.33 days vs 12.89 days, P > .05), but the initial time of acute rejection in intestinal grafts in group A was obviously delayed when compared to group B (8.22 days vs 4.33 days, P < .05), and the rejection scores in group A were remarkably lower than those of group B (0 vs 0.44 on postoperative day (POD) 3, P < .05; 0.22 vs 1.78 on POD 5, P < .05; 1.11 vs 2.56 on POD 7, P < .05). CONCLUSIONS: An immunological advantage on intestinal graft can be induced by simultaneously transplanted liver in auxiliary LSBT. Compared to isolated segmental small bowel allotransplantation, the intestinal graft in LSBT has a delayed initial time of acute rejection and lower acute rejection scores. The liver graft may reduce the risk of intestinal rejection and thus protect the bowel graft.     

Incidence of graft rejection after pancreas and kidney transplantation]

The possibility of an immunological follow-up of the pancreas through the renal transplant after simultaneous pancreaticorenal transplantation (S.P.R.T.) is controversial. Fifty patients have received a neopren-injected extraperitoneal segmental pancreatic transplant and a contralateral renal transplant, after immunological preparation with blood transfusions, without tissue matching but with a negative anti-T lymphocyte cross-match. Immunosuppression consisted in a three- or four-drug therapy during the first 10 days, then a long-term two-drug therapy (ciclosporine and azathioprine). Sixteen rejection episodes were noted in 16 patients during the first 3 postoperative months. No concomitant alteration of the pancreatic function occurred (no pancreatic histology). No isolated pancreatic rejection has been noted so far. One patients presented with 2 episodes of simultaneous rejection 15 and 26 months after transplantation. The actuarial survival rate at 2 years of the patients, kidneys and pancreata respectively is 96%, 92% and 80%. The absence of long-term alteration of the pancreatic function probably proves the absence of undetected pancreatic rejection. In our experience, the follow-up of the renal function allows screening and treating rejection episodes before a possible functional alteration of the pancreatic transplant occurs. In our opinion, extraperitoneal segmental pancreatic transplantation, a simple procedure with satisfactory metabolic results in the long term, is a good technique for S.P.R.T.     

小肠移植中的淋巴管重建

小肠移植的外科手术导致移植物淋巴管引流的完全离断，淋巴管的再生能力及其对小肠移植后移植物生存及功能的影响仍不十分清楚。作者回顾了小肠移植后淋巴管系统的再生，淋巴管重建的技术和影响因素以及小肠淋巴管重建对移植肠功能及生存的意义。分析了小肠移植后淋巴管显微外科重建在临床仍未被应用的原因。     

Increased incidence of acute graft rejection on calcineurin inhibitor-free immunosuppression after heart transplantation

Background

Calcineurin inhibitor (CNI)-free immunosuppression is used increasingly after heart transplantation to avoid CNI toxicity, but in the absence of a randomized trial, concerns remain over an increased rejection risk.

Methods

We studied the incidence of graft rejection episodes among all cardiac graft recipients, beginning with the first introduction of CNI-free protocols. We compared events during CNI-free and CNI-containing immunosuppression among 231 transplant recipients of overall mean age 55.2 ± 11.8 years, from a mean 5.2 ± 5.4 years after transplantation through a mean follow-up of 3.1 ± 1.4 years. We considered as acute rejection episodes requiring treatment those of International Society for Heart and Lung Transplantation.

Results

During the total follow-up of 685 patient years (CNI-containing, 563; CNI-free, 122), we performed 1,374 biopsies which diagnosed 78 rejection episodes. More biopsies were performed in CNI-free patients: biopsies/patient-month of CNI-containing, 0.13 versus CNI-free, 0.22 (P < .05). The incidence of rejection episodes per patient-month was significantly higher on CNI-free compared with CNI therapy, among patients switched both early and later after heart transplantation, namely, within 1 year, 0.119 versus 0.035 (P = .02); beyond 1 year, 0.011 versus 0.004 (P = .007); beyond 2 years, 0.007 versus 0.003 (P = .04); and beyond 5 years: 0.00578 versus 0.00173 (P = .04).

Conclusions

Rejection incidence during CNI-free immunosuppression protocols after heart transplantation was significantly increased in both early and later postoperative periods. Given the potentially long delay to rejection occurrence, patients should be monitored closely for several months after a switch to CNI-free immunosuppressive protocols.     

Colon vs small bowel rejection after total bowel transplantation in a pig model

Abstract  With the advent of FK506, small bowel transplantation has become clinically feasible. Both clinically and experimentally, jeju-nal and ileal biopsies are used for early diagnosis of rejection. More recently, the colon, in addition to the small bowel, has been transplanted to decrease the high incidence of diarrhea after small bowel transplantation. A Bishop-Koop ileostomy allows biopsies on a regular basis, but the diagnosis of rejection remains a problem after takedown of the ileostomy. Rejection of the il-eum is more frequent and more severe than rejection of the jejunum or the colon. Colon biopsy after ileostomy takedown would not rule out rejection of the ileum.     

Heart and liver xenotransplantation under low-dose tacrolimus: graft survival after withdrawal of immunosuppression

BACKGROUND: The hamster-to-rat xenotransplantation model is a useful model to investigate the features of extended host response to long-surviving xenografts. Early xenoantibody responses are T-cell independent and resistant to tacrolimus. Treatment with the combination of mofetil mycophenolate plus FK506 avoids acute xenograft rejection completely, but after withdrawal of immunosuppression hamster grafts are rejected by a process called late xenograft rejection (LXR). METHODS: Hamster hearts and livers were transplanted into Lewis rats. Grafted rats were treated with mofetil mycophenolate (25 mg/kg/day) for 8 days and FK506 (0.2 mg/kg/day) for 31 days. Serum IgM and IgG levels were determined by flow cytometry and interferon-gamma levels by ELISA. IgM, IgG, and C3 deposits were measured in tissue by immunofluorescence, and leukocyte infiltration was measured by immunoperoxidase staining. Results. Survival of heart and liver xenografts in the rats was 48+/-4 days and 63+/-8 days, respectively. After cessation of all immunosuppression, hearts were rejected in 18+/-4 days and livers in 33+/-8 days. Production sequences of xenoantibodies in the two organs differed substantially, especially 7 days after transplantation and at the moment of rejection. Quantification of interferon-gamma levels indicated that there were no significant changes after transplantation. Histological and immunohistochemical studies showed signs of humoral mechanism of LXR in rats undergoing heart transplantation and cellular mechanism of LXR in those that received a liver transplant. Conclusions. These observations suggest that rejection in the hamster-to-rat heart xenotransplantation model is mediated by a T cell-independent B-cell response to which a T cell-dependent B-cell response is added in LXR. In the liver xenotransplantation model, our hypothesis is that LXR is mediated by a mixed cell mechanism, involving lymphocytes CD4+ CD45RC+, macrophages, and cytotoxic T lymphocytes. In summary, we have demonstrated and compared the peculiar features of LXR in two different organs.     

肠移植早期黏膜地址素细胞黏附分子在大鼠移植小肠及其肠系膜淋巴结的表达

目的 探讨黏膜地址素细胞黏附分子（MAdCAM-1）在大鼠小肠移植早期移植肠及其肠系膜淋巴结中的表达及意义。方法 选用近交系F344／N和BN大鼠建立全小肠异位移植模型后分3组：第1组，非手术对照组（F344／N）；第2组，同基因移植组（F344／N→F344／N）；第3组，异基因移植组（BN→F344/N）。术后1、3、5、7d取各组移植肠及其肠系膜淋巴结检测MAdCAM-1表达的分布及变化，同期进行移植肠组织病理学检查。结果 同基因移植组各检测时点的肠黏膜组织表现与正常小肠的组织学特征基本相同；异基因移植组肠黏膜组织表现符合轻-中-重度排斥反应的渐进过程，2周后移植肠绒毛变的低平，散在黏膜上皮脱落，移植肠相关肠系膜淋巴结萎缩明显。MAdCAM-1在急性排斥反应期，高表达于移植肠固有层及其肠系膜淋巴结，特别是高表达于肠黏膜固有层中的扁平血管内皮细胞表面。同基因移植组术后MAdCAM-1的表达在1—7d均无明显量的变化；而异基因移植组MAdCAM-1在移植肠中的表达呈上升趋势，而在其肠系膜淋巴结中的表达呈下降趋势。结论 MAdCAM-1与小肠移植急性排斥反应的进展关系密切。     

Laparoscopic harvesting of small bowel graft for small bowel transplantation

Background: Small bowel transplantation represents a valid therapeutic option for patients with intestinal failure, obviating the need for long-term total parenteral nutrition. Recently, reports have shown the feasibility of performing living related intestinal transplantation using segmental small bowel grafts. The limitations of this technique include inadequate harvested small bowel lengths, as compared with the lengths obtained in cadaveric small bowel harvests, and large incisions for the donor. In this pilot study, we evaluated the feasibility of laparoscopically harvesting long segments of proximal jejunum for small bowel transplantation using a porcine model. The results can be used to evaluate the potential for applying this technique in human cases. Methods: For this study 10 yorkshire pigs were used. Under general anesthesia, each pig underwent laparoscopic segmental resection of 200 cm of proximal jejunum on a vascular pedicle. The harvested graft then was autoreimplanted using an open technique by anastomosing the vascular pedicle to the superior mesenteric vessels. Success was determined 2 hours after anastomosis by visually identifying a pink graft with viable-appearing mucosa, an artery with a strong thrill, and palpable venous flow. The animals were then sacrificed. Results: The mean operation time required to laparoscopically harvest the small bowel graft was 80 min (range, 35–120 min), and the mean length of harvested graft was 220 cm (range, 200–260 cm). The mean length of the graft's vascular pedicle was 4.5 cm (range, 4–5 cm). All 10 grafts were successfully harvested laparoscopically and then reimplanted using an open technique. All the grafts maintained good vascular flow, and showed no evidence of mucosal necrosis at necropsy. Obviously, further studies would be required to examine the long-term results of reimplanting a laparoscopically harvested small bowel graft, but proposals for such studies is beyond the scope of this report. Conclusion: Minimally invasive techniques can be used to harvest proximal small bowel grafts for living related small bowel transplantation.     

小肠移植后亚临床排斥反应的临床病理研究一例

目的 探讨小肠移植后亚临床型细胞性排斥反应(SCR)的临床表现、肠镜下改变和病理特点.方法 小肠移植1例,受者为女性,34岁,供者为男性.应用抗CD52单克隆抗体行诱导治疗,术后单用他克莫司(Tac)、无皮质激素的维持治疗方案.怀疑发生可疑排斥反应(IND)级至I级排斥反应时,提高血Tac浓度,行短程小剂量皮质激素治疗,排斥反应控制不佳时,则行甲泼尼龙冲击治疗;发生中度排斥反应时提高血Tac浓度,给予甲泼尼龙2 g,随后应用皮质激素递减方案.术后头2个月内,每周行2次肠镜和病理学检查,之后频次减为1次/周.结果 至随访结束患者已存活19个月(611 d),期间共发生有临床症状的急性排斥反应6次,亚临床排斥反应3次.3次亚临床排斥反应时,2次肠镜下未见明显改变,1次表现为斑点状的充血、水肿,放大肠镜下绒毛数量轻度减少.3次亚临床排斥反应的病理检查中,1次以黏膜上皮剥脱为主,隐窝上皮损伤较轻,组织学改变符合轻度急性排斥反应;而另2次以隐窝上皮的损伤为主,为可疑急性排斥反应.结论 SCR可能是临床排斥反应的早期阶段,无明显临床症状,肠镜下改变不明显,诊断主要依靠病理学检查,但必须排除移植肠血管病变、肠梗阻、各类炎症等术后并发症.     

小肠移植后亚临床排斥反应的临床病理研究一例

目的 探讨小肠移植后亚临床型细胞性排斥反应(SCR)的临床表现、肠镜下改变和病理特点.方法 小肠移植1例,受者为女性,34岁,供者为男性.应用抗CD52单克隆抗体行诱导治疗,术后单用他克莫司(Tac)、无皮质激素的维持治疗方案.怀疑发生可疑排斥反应(IND)级至I级排斥反应时,提高血Tac浓度,行短程小剂量皮质激素治疗,排斥反应控制不佳时,则行甲泼尼龙冲击治疗;发生中度排斥反应时提高血Tac浓度,给予甲泼尼龙2 g,随后应用皮质激素递减方案.术后头2个月内,每周行2次肠镜和病理学检查,之后频次减为1次/周.结果 至随访结束患者已存活19个月(611 d),期间共发生有临床症状的急性排斥反应6次,亚临床排斥反应3次.3次亚临床排斥反应时,2次肠镜下未见明显改变,1次表现为斑点状的充血、水肿,放大肠镜下绒毛数量轻度减少.3次亚临床排斥反应的病理检查中,1次以黏膜上皮剥脱为主,隐窝上皮损伤较轻,组织学改变符合轻度急性排斥反应;而另2次以隐窝上皮的损伤为主,为可疑急性排斥反应.结论 SCR可能是临床排斥反应的早期阶段,无明显临床症状,肠镜下改变不明显,诊断主要依靠病理学检查,但必须排除移植肠血管病变、肠梗阻、各类炎症等术后并发症.     

小肠移植后亚临床排斥反应的临床病理研究一例

目的 探讨小肠移植后亚临床型细胞性排斥反应(SCR)的临床表现、肠镜下改变和病理特点.方法 小肠移植1例,受者为女性,34岁,供者为男性.应用抗CD52单克隆抗体行诱导治疗,术后单用他克莫司(Tac)、无皮质激素的维持治疗方案.怀疑发生可疑排斥反应(IND)级至I级排斥反应时,提高血Tac浓度,行短程小剂量皮质激素治疗,排斥反应控制不佳时,则行甲泼尼龙冲击治疗;发生中度排斥反应时提高血Tac浓度,给予甲泼尼龙2 g,随后应用皮质激素递减方案.术后头2个月内,每周行2次肠镜和病理学检查,之后频次减为1次/周.结果 至随访结束患者已存活19个月(611 d),期间共发生有临床症状的急性排斥反应6次,亚临床排斥反应3次.3次亚临床排斥反应时,2次肠镜下未见明显改变,1次表现为斑点状的充血、水肿,放大肠镜下绒毛数量轻度减少.3次亚临床排斥反应的病理检查中,1次以黏膜上皮剥脱为主,隐窝上皮损伤较轻,组织学改变符合轻度急性排斥反应;而另2次以隐窝上皮的损伤为主,为可疑急性排斥反应.结论 SCR可能是临床排斥反应的早期阶段,无明显临床症状,肠镜下改变不明显,诊断主要依靠病理学检查,但必须排除移植肠血管病变、肠梗阻、各类炎症等术后并发症.

Abstract：

Objective To investigate the clinical presentation, endoscopy and pathological features of subclinical cellular rejection (SCR) of small bowel allotransplantation. Methods Three times of SCR in a patient after isolated small bowel transplantation were studied by endoscopy and microscopy, and the clinical data and literature were reviewed. Results SCR was an unusual type of acute rejection after small bowel transplantation. SCR showed low-grade morphological changes of acute rejection, and may be relived after low-dose steroid or bolus steroid was given. Conclusion The causes of SCR are not clear now. SCR may be the early stage of clinical acute rejections, and may be correlated with unexpected high grade acute rejection, and chronic loss function of graft. The biopsy through ileoscopy is a "golden standard" of diagnosis of SCR in small bowel transplantation.However, the vessel lesions of graft, ileus, and inflammation should be excluded before diagnosis.     

小肠移植后亚临床排斥反应的临床病理研究一例

目的 探讨小肠移植后亚临床型细胞性排斥反应(SCR)的临床表现、肠镜下改变和病理特点.方法 小肠移植1例,受者为女性,34岁,供者为男性.应用抗CD52单克隆抗体行诱导治疗,术后单用他克莫司(Tac)、无皮质激素的维持治疗方案.怀疑发生可疑排斥反应(IND)级至I级排斥反应时,提高血Tac浓度,行短程小剂量皮质激素治疗,排斥反应控制不佳时,则行甲泼尼龙冲击治疗;发生中度排斥反应时提高血Tac浓度,给予甲泼尼龙2 g,随后应用皮质激素递减方案.术后头2个月内,每周行2次肠镜和病理学检查,之后频次减为1次/周.结果 至随访结束患者已存活19个月(611 d),期间共发生有临床症状的急性排斥反应6次,亚临床排斥反应3次.3次亚临床排斥反应时,2次肠镜下未见明显改变,1次表现为斑点状的充血、水肿,放大肠镜下绒毛数量轻度减少.3次亚临床排斥反应的病理检查中,1次以黏膜上皮剥脱为主,隐窝上皮损伤较轻,组织学改变符合轻度急性排斥反应;而另2次以隐窝上皮的损伤为主,为可疑急性排斥反应.结论 SCR可能是临床排斥反应的早期阶段,无明显临床症状,肠镜下改变不明显,诊断主要依靠病理学检查,但必须排除移植肠血管病变、肠梗阻、各类炎症等术后并发症.     

Compromised kidney graft rejection response in Vervet monkeys after withdrawal of immunosuppressants tacrolimus and sirolimus

BACKGROUND: In nonprimates, organ allografts are often not rejected after withdrawal of immunosuppression. In this study, we examined whether such a phenomenon also occurs in primates. METHODS: Vervet monkeys were transplanted with renal allografts and treated for 60 days with tacrolimus, or tacrolimus plus sirolimus. The drugs were totally withdrawn on day 61. The survival of the monkeys was monitored, and their response to donor- or third party-derived alloantigens was examined in vivo and in vitro. RESULTS: The majority (80-100%) of the grafts survived for at least additional 30 days with no signs of acute rejection. The compromised rejection is donor-specific, because recipient monkeys failed to reject a donor-derived skin graft, but a third-party skin graft was rejected. In vitro mixed lymphocyte reaction and interleukin-2 production in the mixed lymphocyte reaction between the recipients and their donors or between the recipients and a third party had no discernable patterns, and thus did not reflect the in vivo status of the immune system. Although the recipients could not reject the graft acutely after drug withdrawal, the kidney grafts and the donor-derived skin grafts had pathological findings of chronic rejection. CONCLUSIONS: The rejection response of the monkeys to an established graft after withdrawal of immunosuppression is compromised. The compromised rejection is specific and is not due to a permanent alteration of the immune system by the initial drug treatment. The allografts are not inert but have low levels of interaction with the recipient immune system.     

The effect of immunosuppression on peritoneal adhesions formation after small bowel transplantation in rats

BACKGROUND: The reported incidence of adhesion related small bowel obstruction after abdominal organ transplantation is considerably lower than other abdominal procedures. The purpose of the study was to investigate the influence of immunosuppression on peritoneal adhesion formation after intestinal transplantation in rats. METHODS: Four groups of rats (n = 6) underwent small bowel intestinal transplantation in syngeneic (Groups A, B) and allogeneic (Groups C, D) combinations. Groups B and D received tacrolimus immunosuppression 1 mg/kg/d. Animals were euthanized on postoperative day 7, and the total adhesion score (TAS), tissue hydroxyproline content (HPC), TGF-beta mRNA expression levels and histology were examined. RESULTS: All of the animals in Group C showed severe histological (Grade III) acute cellular rejection. There were no histological signs of rejection in Group D. A significant reduction in TAS was observed in tacrolimus treated animals in both syngeneic and allogeneic combinations (Groups B and D), compared with controls (Groups A and C) (P < 0.001 and P < 0.01, respectively). TAS results correlated with the differences in TGF-beta levels that showed significant reduction when each immunosuppressed group was compared with its nontreated counterpart, i.e., (Groups B versus A, P < 0.05, and Groups D versus C, P < 0.01). TGF-beta levels were significantly high in the rejection group (C) and correlated with the intense adhesion formation that was demonstrated in that group. Group C was also the only group in which a significant elevation in HPC was demonstrated (P < 0.001). CONCLUSION: Intense adhesion formation occurs during early posttransplant acute rejection. Postsurgical adhesion formation is significantly reduced in immunosuppressed rats after intestinal transplantation.     

Incidence of small bowel obstruction after laparoscopic and open colon resection

Background

Small bowel obstruction (SBO) is responsible for more than 1 billion dollars in health care costs yearly in the United States. We sought to evaluate whether laparoscopic colorectal surgery resulted in a decreased incidence of SBO within the first year of surgical resection compared with open surgery.

Methods

From January 2003 to December 2008, 339 patients underwent open (open colorectal resection [OPEN]) colorectal resection and 448 patients underwent laparoscopic (laparoscopic colorectal resection [LAP]) colorectal resection. Hospital admissions up to 1 year after the initial resection identified patients admitted for the management of SBO, ileus, or nausea and vomiting.

Results

During the 1st year after surgery, 6 patients in the OPEN group developed SBO, and 5 patients in the LAP group developed SBO. The overall frequency of SBO for the OPEN group was 1.8% and 1.1% for the LAP group (P < .5461).

Conclusions

Although advantages such as quicker postoperative recovery and decreased hospital stay have been attributed to laparoscopic surgery, no difference in the incidence of SBO within the 1st year of surgery was found compared with open colorectal surgery.