Method Article
Porcine models of organ transplantation provide an important platform to study mechanisms of organ preservation. This article describes a heterotopic porcine renal autotransplantation model, which allows investigating new approaches to improve the outcome of transplantation using marginal kidney grafts.
Kidney transplantation is the treatment of choice for patients suffering from end-stage renal disease. It offers better life expectancy and higher quality of life when compared to dialysis. Although the last few decades have seen major improvements in patient outcomes following kidney transplantation, the increasing shortage of available organs represents a severe problem worldwide. To expand the donor pool, marginal kidney grafts recovered from extended criteria donors (ECD) or donated after circulatory death (DCD) are now accepted for transplantation. To further improve the postoperative outcome of these marginal grafts, research must focus on new therapeutic approaches such as alternative preservation techniques, immunomodulation, gene transfer, and stem cell administration.
Experimental studies in animal models are the final step before newly developed techniques can be translated into clinical practice. Porcine kidney transplantation is an excellent model of human transplantation and allows investigation of novel approaches. The major advantage of the porcine model is its anatomical and physiological similarity to the human body, which facilitates the rapid translation of new findings to clinical trials. This article offers a surgical step-by-step protocol for an autotransplantation model and highlights key factors to ensure experimental success. Adequate pre- and postoperative housing, attentive anesthesia, and consistent surgical techniques result in favorable postoperative outcomes. Resection of the contralateral native kidney provides the opportunity to assess post-transplant graft function. The placement of venous and urinary catheters and the use of metabolic cages allow further detailed evaluation. For long-term follow-up studies and investigation of alternative graft preservation techniques, autotransplantation models are superior to allotransplantation models, as they avoid the confounding bias posed by rejection and immunosuppressive medication.
Kidney transplantation is the treatment of choice for patients with end-stage renal disease, due to associated lower rates of morbidity and mortality when compared to dialysis 1-3. Despite major improvements in patient outcomes following kidney transplantation, graft shortage still poses a severe challenge worldwide. The number of patients waiting for a kidney transplant by far exceeds the number of organs available 4-6. To increase the number of kidneys available for transplantation and to reduce patient waiting times, further sources of kidney grafts are needed.
Commonly, standard criteria donor (SCD) and extended criteria donor (ECD) kidney grafts from donation after brain death (DBD) as well as kidneys recovered from live donors (LDKT) are utilized. Since the 1990s, an increasing number of kidney grafts have been recovered in a donation after circulatory death (DCD) scenario, to further expand the donor pool 7,8. However, DCD and ECD kidney grafts demonstrate acceptable but decreased outcomes after transplantation, depending on different factors, such as donor age, warm and cold ischemia times, and the preservation technique used 9-11. Thus, additional research is required to improve the outcome of patients receiving marginal kidney grafts and to further increase the donor pool.
The porcine model of renal transplantation is well established and provides a clinical important scenario to investigate innovative approaches for the improvement of marginal kidney graft outcomes. In contrast to rodent and canine kidneys, which are unilobular, porcine and human kidneys are multilobular and are anatomically similar, particularly in regard to the arterial, venous, and urinary collecting systems 12,13. In addition, porcine and human kidneys demonstrate similarities in the pathophysiology of ischemia reperfusion injury (IRI), biochemistry, and immunological parameters 14. Thus, porcine renal transplantation is well-suited to investigate new organ preservation methods for marginal kidney grafts 15-17, model human IRI 18, study immunological pathways and allograft tolerance 19, provide surgical training 20-22, test new pharmacological therapies 23, implement new medical devices, and study new immunological mechanisms in xenotransplantation 24-26.
The renal porcine and human transplantation settings are not completely analogous. This article focuses on important technical details that will facilitate successful establishment of a renal autotransplantation model. Species-adapted pre- and postoperative housing, administration of anesthesia with close monitoring, and matched surgical techniques are described in the protocol and demonstrated in the video. Resection of the contralateral native kidney provides the opportunity to assess the function of the transplanted kidney. The placement of venous and urinary catheters and the use of metabolic cages allow more in-depth assessment. For studies aimed at investigating alternative graft preservation methods and mechanisms of IRI, autotransplantation models are superior to allotransplantation models, as they avoid the complications and confounding bias associated with rejection and use of immunosuppressive medications.
所有动物人文关怀,我们按照加拿大议会关于动物保护的政策和指导方针进行了所有的研究。所有的程序都被下批准的大学健康网络机构动物护理委员会,动物使用的协议进行的。
注意:研究方案的示意性概述图1中。
图1.研究协议。 请点击此处查看该图的放大版本。
1.动物
2.移植肾检索
3.肾移植术
4.手术后跟进
在下文中,自体肾移植实验的结果(n = 4时)的证明。在移植肾检索后,猪收回他们的住房面积。同时,肾移植物在冰上储存为7小时35分钟(±18分钟)的平均时间。麻醉和重复剖腹手术的再诱导后,对侧肾脏切除和上述冷保存移植异位移植。从呼吸机断奶后,猪从手术恢复,并随访10天( 参见图1)。每日(1-4术后天;荚果),或每隔一天(6-10荚)血样收集进行血气分析;评估肾功能,血肌酐和尿素氮(BUN)值估计。为了对比,人们allotransplanted肾移植物的结果。对于免疫抑制,这只猪接受环孢素100毫克PO和合作rtisone 250毫克ivbid使用的外科技术是一样的,在自体移植的协议;无热缺血时间的应用。
所有的猪在随访期间均处于良好的临床状况。血清肌酐和尿素氮值显示为一天手术后的最高涨幅(克雷亚2.8±0.7毫克/分升,BUN 25.3±7毫克/分升),并下降至箱体10(克雷亚1.7±0.4毫克/分升,BUN 10.7±4毫克/分升)接近初始基准值。该allotransplanted移植肾表现出较高的肌酐和尿素氮值之后,良好的初始移植物功能,相比自体移植,很可能是由于拒绝时(图2 和图3)。酸碱止血( 图4)和电解质水平(图5)是稳定的,没有干预。组织学检查显示,自体移植的肾间质保存(FIGURË6),以及弥漫性间质炎症,小管炎和肾小球肾炎的肾脏allotransplanted(图7)。
基线图2.血清肌酐值,血清肌酐值(均值和标准差)和10个手术。 请点击此处查看该图的放大版本。
图3.血清尿素氮值,血清尿素氮值(均值和标准差)为基准10天手术后。 请点击此处查看该图的放大版本。
手术后图4.酸碱止血。酸碱止血(均值和标准差)为基线和10天。 请点击此处查看该图的放大版本。
图5.电解质水平。电解质水平(均值和标准差)为基线和手术后10天。 请点击此处查看该图的放大版本。
图6.组织学(H& E),放大100倍的自体移植肾间质正常手术后10天,请点击此处查看该图的放大版本。
图7.组织学(H&E),放大100倍,广泛的间质炎症,小管炎和肾小球肾炎,具有抑制一致,在手术后10天allotransplanted肾。 请点击此处查看该图的放大版本。
猪肾移植模型提供了进一步的人类移植领域的一个独特的机会,由于在手术方面,生理学,生物化学和免疫学14相似之处。
根据实验研究的目的,自体肾移植的模型相比,同种移植模型的几个优点。虽然异体移植后28几组报告好移植肾功能,免疫猪是具有挑战性的,尤其是在肾移植。术前血液样本进行分析,以确保猪白细胞抗原(SLA)的兼容性是可行的,但价格昂贵,不切实际14。术后,提出免疫抑制剂如他克莫司和环孢霉素(钙调磷酸酶抑制剂,CNI)口服给药或静脉28。口服给药是不切实际的,因为猪通常拒绝吞咽口服药物学化。此外,肠梗阻可能避免免疫抑制药物和治疗药物水平维持足够的吸收。 CNI的IV在活跃动物连续输注技术要求高。静脉推注施用导致高的峰值,导致毒性。因此,对于新的保存技术的调查,自体肾移植的模型有几个优点。在上述演示的allotransplantated肾移植,肌酸酐和BUN的延迟和增加的峰值的代表性结果表明抑制,其通过组织学评估证实。
自体移植的猪模型先前已用于研究新的保鲜技术14,18,29。然而,在一个心脏跳动情形自体移植的猪的报道术后血清肌酸酐和BUN值的变化很大,取决于实验系统22,30上。我们在座的心脏跳动的捐赠协议,导致2.8毫克/分升(±0.7)和25.3毫克/分升BUN峰(±7.4)低术后血清肌酐高峰。这些结果与由ハント和同事28和 Snoeijs和同事31呈现的低峰值相媲美。
为了确保在猪自体移植模型肾移植后成功的结果,我们已经确定了几个关键的技术因素,最大限度地减少某些并发症的发生率。相比威斯康星州(UW)解决方案时,大学使用的组氨酸,色氨酸酮戊二酸溶液(HTK)减少血管痉挛的风险,由于钾的含量较低。进一步降低在再灌注点血管痉挛的危险,维拉帕米可注入肾动脉,和罂粟碱可局部检索期间和再灌注后给药。另外,去甲肾上腺素的连续滴注滴定以保持收缩期血压高于100毫米汞柱,确保均匀的灌注。它是保持至少直到猪被定位容易发生这种血压有用。此外,移植移植物的定位是很重要的,以防止新吻合血管的扭结。因此,它是有帮助的对侧左肾切除缝合移植物的吻合,以避免大量的机械操作之前。整理输尿管吻合术,包小肠周围的移植移植术后固定腹壁关闭后其位置。并发症,如因肠扭结肠梗阻很少观察到,但可能会导致严重的并发症,包括肠梗阻,肠穿孔和死亡。总体而言,精确的手术技术,麻醉周到,密切监测随访期间确保良好的临床疗效和移植物功能。
动脉和静脉吻合,可以PERFO使用不同的技术Rmed指。移植物的原位放置允许肾动脉和静脉端 - 端吻合。在异位移植的情况下,该接枝可定位在对侧肾窝为端 - 端吻合术,到髂血管,或直接在远端主动脉。与吻合异位移植到主动脉和静脉直接在端-端技术是优选的在此模型中,因为它可以降低血栓形成和血管痉挛32的风险。具有非常早静脉分叉解剖变异可能导致需要缝制两个单独静脉吻合。如果动脉或静脉相对较短,接枝可旋转180°以获得所述容器的长度。输尿管一侧到侧吻合可以取得良好的实验结果没有复杂狭窄或泌尿泄漏。
一般情况下,相对于其他动物模型肾移植的猪模型提供了优势。为D上述旁切,猪和人的设置,这使得新的技术相对快速翻译到临床实践之间存在着一定的相似性。相比啮齿动物模型中移植的技术在技术上是容易。此外,通过静脉导管的安置,外周血样品可以容易地收集并进行进一步的调查处理。尿液收集允许肾损伤和功能的进一步评估。收集尿液样品,经皮导管可以插入膀胱。为了避免操作由猪,远端应皮下隧道传送到动物的背部。用于收集尿液的另一个选择是利用代谢笼,这允许延长收集期间来估计在尿中的肌酸酐清除率和另外的生物标记的浓度。超声,CT扫描和MRI图像是可能的。循环后死亡捐赠协议可以通过应用来温暖模仿缺血以取回之前。此外,猪都比较容易处理,如果被阉割,以限制他们的攻击行为。
缺点包括动物采购,住房,手术等医疗设备和人力的高成本。这些因素意味着它是不可行的包括各研究组在大量的动物。此外,相比于啮齿动物模型,引用有限数量的在文献中为猪规范生物数据可用。作为新开发的技术,如新颖的保存方法的评估的一个替代方案中,其它基团所描述的常温离体灌注作为替代肾移植33,34。这种技术是更容易执行,更便宜。然而,标准化的肾移植体的移植提供了更多的类似于临床实践的模式,并允许较长的后续周期。因此,服务于一个更现实的评估移植换货。
总之,异位自体肾移植的猪模型提供了探讨移植肾成果的改进创新新方法临床重要的场景。特别是,该协议提供重要的技术细节,这将有利于成功建立自体肾移植模型,并允许新的调查结果的临床试验的快速翻译。
The authors have nothing to disclose.
We thank the Sorin Group (Milano, Italy), XVIVO Perfusion Inc. (Goteborg, Sweden), and Braun AG (Melsungen, Germany) for their support. We highly appreciate the support of the John David and Signy Eaton Foundation.
Name | Company | Catalog Number | Comments |
Anesthesia Equipment | |||
Anesthesia Machine, Optimax | Moduflex Anesthesia Equipment | SN5180 | |
Infusion Pump 3,000 | SIMS Graseby LTD. | SN300050447 | |
Infusion Pump Line | Smith Medical ASD Inc. | 21-0442-25 | |
Intravenous permanent catheter (9.5 Fr) | Cook Medical Company | G01865 | |
Isoflurane Vapor 19.1 | Draeger Medical Canada Inc. | N/A | |
Mallinckrodt, Tracheal Tube, 6.5 mm | Covidien Canada | 86449 | |
Temperature Therapy Pad | Gaymar Industries Inc | TP26E | |
Ventilator, AV 800 | DRE Medical Equipment | 40800AVV | |
Warm Touch, Patient Warming System | Nellcor/ Covidien Canada | 5015300A | |
Name | Company | Catalog Number | Comments |
Surgical Equipment | |||
Abdominal Retractor | Medite GmbH | 07-0001-00 | |
Aorta/vein punch 4.0 mm, round | Scanlan International Inc. | 1001-602 | |
De Bakey, Atraumatic Peripheral, Clamp | Aesculap Inc. | FB463R | |
De Bakey-Beck, Atraumatic Vena Cava, Clamp | Aesculap Inc. | FB519R | |
De Bakey, Atraumatic Mini-Bulldog, Straight | Aesculap Inc. | FB422R | |
De Bakey, Atraumatic Mini-Bulldog, Curved | Aesculap Inc. | FB423R | |
De Bakey, Atraumatic Coarctation Clamp, Angled | Aesculap Inc. | FB453R | |
Dissection Blade #11 | Feather Safety Razor Co. | 089165B | |
Connector (1/4") with male luer lock | Sorin Group Inc. | AB1452 | |
Liver Admin Set (flush line) | CardioMed Supplies Inc | 17175 | |
Maxon, 1 | Covidien Canada | 606173 | |
Med-Rx Suction Connecting Tube | Benlan Inc. | 70-8120 | |
Organ Bag | CardioMed Supplies Inc | 2990 | |
Potts – De Martel, Scissors | Aesculap Inc. | BC648R | |
Renal artery cannula, 1.6" | Sorin Group Inc. | VC-11000 | |
Sofsilk, 2-0 | Covidien Canada | S405 | |
Sofsilk, 3-0 | Covidien Canada | S404 | |
Satinsky, Suprahepatic Cava Clamp | Aesculap Inc. | FB605R | |
Suction Tip | Tyco Healthcare Group LP | 8888501023 | |
Surgipro II, 6-0 | Covidien Canada | VP733X | |
Valleylab, Cautery Pencil | Covidien Canada | E2515H | |
Valleylab, Force Tx | Valleylab Inc. | 216151480 | |
Valleylab, Patient Return Electrode | Covidien Canada | E7507 | |
Name | Company | Catalog Number | Comments |
Medication | |||
Atropine Sulfate 15 mg/30 ml | Rafter 8 Products | 238481 | |
Buprenorphine 0.3 mg/ml | RB Pharmaceuticals LDT | N/A | |
Ceftiofur 3 mg/ml | Pfizer Canada Inc. | 11103 | |
Cefazolin 1 g | Pharmaceutical Partners of Canada Inc. | 2237138 | |
Fentanyl Citrate 0.25 mg/5 ml | Sandoz Canada Inc. | 2240434 | |
Heparin 10,000 iU/10 ml | Sandoz Canada Inc. | 10750 | |
Histidine-tryptophan-ketoglutarate (HTK) solution | Methapharm | CU001LBG | |
Isoflurane 99.9%, 250 ml | Pharmaceutical Partners of Canada Inc. | 2231929 | |
Ketamine Hydrochloride 5,000 mg/50 ml | Bimeda-MTC Animal Health Inc. | 612316 | |
Lactated Ringer’s + 5% Dextrose 1 L | Baxter Corporation | JB1064 | |
Lactated Ringer’s 1 L | Baxter Corporation | JB2324 | |
Metronidazole 500 mg/100 ml | Baxter Corporation | 870420 | |
Midazolam 50 mg/10 ml | Pharmaceutical Partners of Canada Inc. | 2242905 | |
Norepinephrine 16 mg/250 ml Dextrose 5% | Baxter Corporation | N/A | |
Pantoprazole 40 mg | Sandoz Canada Inc. | 2306727 | |
Papaverine 65 mg/2 ml | Sandoz Canada Inc. | 9881 | |
Propofol 1,000 mg/100 ml | Pharmascience Inc. | 2244379 | |
Saline 0.9%, 1 L | Baxter Corporation | 60208 | |
Solu-Medrol 500 mg | Pfizer Canada Inc. | 2367963 | |
Verapamil | Sandoz Canada Inc. | 2166739 | |
Xylocaine Endotracheal 10 mg/50 ml | AstraZeneca | 2003767 |
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