Preservation of the ureteral blood supply in rat renal transplantation

Ureteral anastomosis with a polyimide stent in rat kidney transplantation

Background: Complications associated with ureteral anastomosis in kidney transplantation are highly prevalent, despite the development of various types of stents. The current stent materials and placement methods have several limitations. This study attempts to provide an alternative by investigating ureteral anastomosis with a polyimide stent and a modified placement method in a rat model of kidney transplantation.Methods: Sprague-Dawley rats were randomly divided into Group I: sham operation, Group II: autologous ureteral anastomosis, and Group III: isogenic kidney transplantation with ureteral anastomosis. For the anastomosis, a polyimide stent with a previously placed 11-0 silk was inserted into the ureter. The stent and ureter were fixed with 11-0 silk sutures. The kidney weight and serum creatinine were recorded. The ureteral and renal sections were taken for histological analysis.Results: None of the stents had migrated. Urethral patency was achieved. Further, there were no evident histological changes in the anastomosed ureters. The serum creatinine level in group III was significantly higher than the other two groups, but there was no significant difference in kidney weight among the groups at postoperative week 12. Finally, the histological structure of kidneys in groups II and III only showed minor changes.Conclusions: The current anastomosis method with polyimide stent causes minimal damage to the ureteral walls and minimizes the possibility of stent migration. Therefore, this method of ureteral anastomosis with the polyimide stent should be explored for its potential benefits in more animal kidney transplantation models, thus providing an alternative for the clinical setting.

Complications and Their Prevention in Experimental Renal Transplantation in Rats

OBJECTIVES

Experimental rat models of renal transplant have played a pivotal role in renal transplant research. Both intraoperative and postoperative complications during donor nephrectomy and implantation in the recipient can be associated with significant morbidity and mortality. The aim of this paper is to discuss the incidence, pathophysiology, and prevention of complications that occurred in the process of establishment of a rat model of chronic allograft injury at our institution.

MATERIALS AND METHODS

The complications observed while performing 67 consecutive donor nephrectomies and 61 renal transplants were recorded prospectively, and appropriate measures were taken to prevent these complications in the subsequent transplant procedures.

RESULTS

Donor-related complications included failure of the kidney to clear of blood by the kidney perfusion solution and intraoperative deaths. The recipient-related complications included intraoperative hemorrhage, inadequately perfused kidneys with dusky appearance, congested and paralyzed hind limbs, urine leak, necrosis of the kidneys, renal and bladder calculi formation, and death during and after kidney transplant.

CONCLUSIONS

Complications during donor nephrectomy and renal transplant can lead to significant loss of kidneys and animals. Proper recognition can allow appropriate measures to be taken to prevent these complications, thus achieving high-quality transplants and prolonged graft and animal survival.

Review of Surgical Techniques of Experimental Renal Transplantation in Rats

Microvascular surgical techniques of renal transplant in rats have evolved over the past 5 decades to achieve successful rat renal transplant; these modifications have included surgical techniques to address the anatomic variations in the renal blood vessels and those to reduce ischemic and operation durations. Here, we review the surgical techniques of renal transplant in rats and evaluate the advantages and disadvantages of individual techniques of vascular and ureteric anastomoses. For this review, we performed a systematic literature search using relevant medical subject heading terms and included appropriate publications in the review. Since the first description of a rat model of renal transplant by Bernard Fisher and his colleagues in 1965, which used end-to-side anastomosis between the renal vein and renal artery to the recipient inferior vena cava and aorta, several vascular and ureteric anastomosis techniques have been modified. Vascular anastomosis techniques now include end-to-end anastomosis, use of donor aortic and inferior vena cava conduits, sleeve and cuff anastomoses, and application of fibrin glue. Likewise, restoration of the urinary tract can now be achieved by direct anastomosis of the donor ureter to the recipient bladder, end-to-end anastomosis between the donor and recipient ureters, and donor bladder cuff to the recipient bladder. There are advantages and disadvantages attributable to individual techniques. The range of vascular and ureteric anastomosis techniques that has emerged reflects the need for mastering more than one technique to suit the vascular anatomy of individual animals and to reduce operating time for achieving successful outcomes after renal transplant.

Methods in renal research: kidney transplantation in the rat

Kidney transplantation in small animals has been crucial in the development of anti-rejection therapies. While there is no substitute for a skilled microsurgeon, there are many aspects of the transplant procedure that can be modified to optimize the reproducibility and utility of the technique. This article provides a detailed description, including video recording, of orthotopic kidney transplantation in the rat. The key variables in the technique are also discussed.

Impact of ureteral length on urological complications and patient survival after kidney transplantation

BACKGROUND

Urologic complications are of the most important complications after kidney transplantation which increases mortality and morbidity significantly.

OBJECTIVES

We designed this study to evaluate the association between ureteral length and postoperative complications.

PATIENTS AND METHODS

We recorded the length of the transplanted ureter during the operation. Ureter-to-bladder anastomosis was performed using modified Lich-Gregoir method on the ureteral stent. Complications like urine leakage and increased creatinine were evaluated. We used both univariate and multivariate analyses and survival analysis according lengths of ureter. It means that the main variable is ureteral length and other variables are studied based on it.

RESULT

A total of 395 patients with the mean age of 37 years (range, 18 to 68 years) were enrolled in the study, twenty six graft lost during the follow-up period. The Mean age of recipients was 37 ± 13 years. Urinary stenosis was seen in 6 patients (1.5%) and urinary leakage in 4 (1%) patients. The complication rate was not significantly different between these groups (P = 0.67). We found that there were no significant difference among complication (P = 0.25), hospitalization (P = 0.31) and survival (P = 0.84) at 5.5 cm length cut off.

CONCLUSIONS

The length of transplanted ureter does not affect the postoperative urologic complications (including urinary fistula and ureter-to-bladder anastomosis stricture), and it seems that decreased rate of complication frequency during the recent years is due to technical improvement, surgeon's skillfulness and development in use of immunosuppressant's postoperatively.

Kidney transplantation procedures in rats: assessments, complications, and management

Kidney transplantation in rats is an experimental model often used for the development of general microsurgical or transplantation techniques, for immunologic studies, and for analyzing transplant-associated long-term arterial blood-pressure changes. The aim of the present study was to analyze different surgical techniques of kidney transplantation in rats, with emphasis on minimizing surgical complications and establishing guidelines for their prevention and management. Complications were categorized into general (e.g., core body temperature drop, ischemic time) and surgically related vascular and urinary tract complications. In conclusion, a significant reduction of the complication rate in renal transplantation in rats can be achieved by placing the animal on a heating pad at an appropriate temperature. To reduce the risk of vascular thrombosis, ice-cold saline with heparin and careful flushing of the donor kidneys are recommended. Vascular complications can be avoided by performing "end-to-end" anastomosis techniques. The use of stents and cannulas in the urinary tract is associated with a high risk of urinary tract obstruction, and therefore is not recommended.

Kidney transplantation in rats: an appraisal of surgical techniques and outcome

Renal transplantation in rats is an essential experimental tool in transplantation research. The surgical procedure per se could affect the outcome of an experiment, independent of the hypothesis addressed, therefore requiring a standardized method which should be comparable across studies. To date, however, there is little information on the optimal surgical technique. We performed a Medline search on original articles published between 1965-2001 in order to evaluate whether specific technical issues affecting the outcome of the procedure could be defined. Articles that reported on a novel microsurgical procedure, or whose main purpose was the outcome of a surgical technique itself, were included in the analysis. From 2,060 retrieved publications, 34 corresponded to the selection criteria (rats and microsurgery and technique and kidney or renal transplantation). Among the essential determining factors for a good outcome, body weight >200 g and warm ischemic time <30 min were identified. Other important factors were the techniques used for vascular (end-to-end and end-to-side procedure or sleeve technique) and ureteral (bladder patch or end-to-end procedure) anastomosis. Gender, animal strain, type of anesthesia, prophylactic administration of antibiotics, and type of flushing solution did not affect the success of renal allografts. In order to avoid a bias related to the surgical procedure in rat renal transplantation, a warm ischemia time <30 min in animals with a body weight >200 g seems to be essential. Also, end-to-end or end-to-side vascular anastomoses are preferable to the sleeve technique. Other factors do not influence the immediate function of the graft.