Transplantation/ImmunologyInnovative, simplified orthotopic lung transplantation in rats
Introduction
Lung transplantation represents the only curative treatment option for patients with end-stage pulmonary disease. Refinements in the surgical techniques during the past 30 years and novel immunosuppressive regimens have resulted in marked improvements in the overall outcome and patient survival after lung transplantation [1]. Despite these improvements, long-term graft survival has been significantly limited by bronchiolitis obliterans syndrome (BOS) [1], [2]. Ischemia–reperfusion injury is an additional, rather acute, problem resulting in the risk of acute graft failure in clinical lung transplantation [2], [3], [4], [5]. Our understanding of the molecular processes involved in ischemia–reperfusion injury is that inflammatory and mechanical insults to the endothelium of the microvasculature trigger an injury with a deleterious tissue response [6], [7]. The mechanisms underlying BOS development, however, are not clearly understood. When considering the incidence of BOS (i.e., developing in 50% of recipients within 5 years and 75% within 10 years after lung transplantation), it becomes clear that novel therapeutic strategies are urgently desired for BOS treatment [2].
Novel approaches using molecular tools in counteracting ischemia–reperfusion injury and BOS necessitate standardized lung transplant models in animals. Although large animal models are currently available [8], rodent transplant models have the advantage of significantly lower costs and the availability of several plasmids and vectors for application in this species [9], [10]. Asimacopoulos et al. [11] first reported on orthotopic rat lung transplantation in 1971. Mizuta et al. [12] reported the cuff technique for rat lung transplantation, which facilitates anastomoses of the pulmonary artery and vein, in 1989. Furthermore, they described a suture technique for bronchial anastomosis [12]. Reis et al. [13] described a nonsuture external cuff technique that did not require microscopic suturing of the vessels or bronchus. More recently, Goto et al. [14] reported a technique of interposing parts of the donor rat's descending aorta to complete the anastomoses of the corresponding bronchovascular structures. However, the major obstacles associated with these models have been that they were not physiological, such as was the case for the model reported by Goto et al. [14], had high dropout rates and high complication rates, or required extensive microsurgical training and the presence of two surgeons to perform the procedure. Complications, such as arterial bleeding, venous bleeding, anastomotic leakage, bronchial stenosis, bronchial leakage, hematothorax, and pneumothorax, have been the major limiting factors in animal survival and operative outcome.
Thus, we established a simplified and reproducible orthotopic single lung transplant procedure in rats with excellent short- and long-term survival rates that can be performed by a single surgeon. We report on a precision, triple axis, vascular clip stabilizer (Fig. 1A), which markedly facilitated the procedure and allowed reproducible anastomoses. We have provided blood gas analysis results of blood drawn directly from the left pulmonary vein 60 min after reperfusion and the examination results of histologic sections of the left lung allografts 60 min and 24 h after transplantation to prove regular histologic features, physiological integration, and proper post-transplant function.
Section snippets
Development of the triple axis stabilizer
An aluminum plate served as the base for a 15-cm-long steel cylinder (Fig. 1A) that was probed with an L-shaped 2-mm steel wire. The cylinder was tapped on the side to allow for vertical movement in the cylinder and fixation of the wire with a screw (Fig. 1A). A commercial mosquito clamp was mounted on top and fixed with an articulated joint (Fig. 1B). Intraoperatively, an aneurysm clip (Aesculap FE720 Miniclip, Aesculap, Central Valley, PA), clamping the cuffed vessels and the recipient
Results
A total of 90 transplantations were performed. On average, the donor operation lasted 20 ± 2 min, and the left lung dissection of the donor bronchovascular structures lasted 20 ± 2 min. Implantation and revascularization required 90 ± 5 min, on average. Including the time needed to perform all anastomoses (10 ± 1 min for the bronchial anastomoses and 5 ± 1 min for each vascular anastomosis), we achieved ischemia times as short as 40 min.
Our technical success rate was 95%. Perioperative
Discussion
We have reported on a novel model of orthotopic single lung transplantation in rats. It is a straightforward procedure that addresses many of the limitations described with previous methods. In contrast to other investigators using the cuff technique, we are the first group to use a proximal cuff technique by placing an 18-gauge polyethylene intravenous catheter on the recipient pulmonary artery and a 16-gauge cuff on the pulmonary vein, instead of cuffing the donor vasculature [12], [13], [15]
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Cited by (12)
Right lung transplantation with a left-to-right inverted anastomosis in a rat model
2022, JTCVS OpenCitation Excerpt :Based on the existence of the left-to-right inverted technique, the advantage in time will be extended to the current right LTx model. In previous studies, acute hemorrhage caused by cuff slipping and vascular injury was the main cause of intraoperative death in rats, leading to an overall survival of less than 90%.19,20 Three recipients (7.5%) died of intraoperative bleeding in a previous study on right LTx by Li and colleagues6 likely because of the short length of the main right PV that was everted over the cuff.
Effects of cold or warm ischemia and ex-vivo lung perfusion on the release of damage associated molecular patterns and inflammatory cytokines in experimental lung transplantation
2021, Journal of Heart and Lung TransplantationCitation Excerpt :In each group, total storage time with or without EVLP was 7 hours, after which the lungs were separated. A bronchoalveolar lavage (BAL) was performed in the right lung, and the left lung was transplanted according to Habertheuer et al18, with independent graft ventilation.5 Recipient rats were anesthetized, tracheotomized, mechanically ventilated, their left native lung was removed, and the pulmonary artery (PA) and vein (PV) were anastomosed to those from the donor lung.
Technical Aspects and Benefits of Experimental Mouse Lung Transplantation
2016, Archivos de BronconeumologiaLearning curve and key procedures analysis of modified rat models of orthotopic left lung transplantation
2021, Organ TransplantationTechniques for lung transplantation in the rat
2019, Experimental Lung ResearchVein Suturing Results in Worse Lung Graft Outcomes Compared to the Cuff Method
2019, European Surgical Research