Laparoscopic surgery for kidney orthotopic transplant in the pig model

Laparoscopic Orthotopic Kidney Transplantation in Swine: A Novel Vascular Prop Device for Venous Anastomoses

Objective: To investigate the safety and efficacy of a vascular prop device for laparoscopic orthotopic kidney transplantation (LOKT) in swine.

Material and Methods: Twenty swine were randomly divided into two groups. A vascular prop device was used in the observation (VP) group, and the vein beltization technique was used in the control (VB) group. The right kidney, as a donor graft, was laparoscopically transplanted to the location of the left kidney after a left nephrectomy. Data on the operative time, venous anastomotic time, vein stenosis, etc., and the survival of the swine in the two groups were recorded.

Results: The mean transplant operative time, the mean cold ischemia time, and the venous anastomotic times in the VP group were significantly shorter than those in the VB group. Seven swine in the VP group and three swine in the VB group survived for 7 days. Autopsy results showed the occurrence of one artery stenosis and one vein stenosis in the VP group and one artery stenosis and five vein stenoses in the VB group. The median survival time was 6.25 days for the swine in the VP group and 4.40 days for those in the VB group.

Conclusions: The vascular prop device is safe and feasible for LOKT in swine and may accelerate venous anastomosis and ensure the quality of venous anastomotic stoma.

Investigation of a method for long-term preservation of the vascular allograft

BACKGROUND/OBJECTIVE

During multiple organ procurement, blood vessels are routinely retrieved and stored in University of Wisconsin solution and then discarded after two weeks, if not used at organ transplantation owing to lack of a method for long-term preservation. Therefore, the aim of this study is to investigate a method for long-term preservation of vascular allografts in ethanol.

METHODS

Aorta and vena cava allografts were retrieved and stored in 75% ethanol solution for 12 months at 4°C. Four pigs were divided into two groups. A segment of aorta was excised and replaced by insertion of preserved aorta graft (Group A) or vena cava graft (Group V). The pigs were observed for six weeks. A laparotomy was performed and the vascular graft was harvested for histopathology followed by euthanasia at the end of study.

RESULTS

Three pigs recovered uneventfully, while one pig died from venous graft rupture in the third week after surgery. There was no aneurysmal formation or thrombosis in the grafts. Some calcification was seen over aorta allograft. On histopathology, the elastic pattern was almost normal, although the endothelial cells degenerated after preservation. After implantation, the formation of the endothelium cell-like layer was seen in both aorta and vena cava allografts.

CONCLUSION

Vascular allografts were functional after preservation for 12 months. The vena cava grafts had much less wall calcification than the aorta grafts. Further studies are necessary to investigate vascular graft remodelling with a longer observation period after implantation.

Porcine models of acute kidney injury

Pigs represent a potentially attractive model for medical research. Similar body size and physiological patterns of kidney injury that more closely mimic those described in humans make larger animals attractive for experimentation. Using larger animals, including pigs, to investigate the pathogenesis of acute kidney injury (AKI) also serves as an experimental bridge, narrowing the gap between clinical disease and preclinical discoveries. This article compares the advantages and disadvantages of large versus small AKI animal models and provides a comprehensive overview of the development and application of porcine models of AKI induced by clinically relevant insults, including ischemia-reperfusion, sepsis, and nephrotoxin exposure. The primary focus of this review is to evaluate the use of pigs for AKI studies by current investigators, including areas where more information is needed.

Extraperitoneal Laparoscopic Kidney Transplantation: Preliminary Clinical Experiences from China

OBJECTIVE

To report on the pioneering clinical experiences of six cases of extraperitoneal laparoscopic kidney transplantation in China.

METHODS

For the first time in clinical practice, a customised, controllable double-circulation cooling device was used to protect the transplanted kidney. Of the six patients, two underwent an allograft renal transplantation because they had been diagnosed with uraemia and were on maintenance haemodialysis. The other four patients underwent kidney autotransplantation because of a central renal tumour.

RESULTS

The extraperitoneal laparoscopic kidney transplantations were successfully completed between 2017 and 2018. The operative time for the two patients undergoing the allograft transplantation was 3-3.5 h. The time for venous anastomosis was approximately 53-65 min, and the time for arterial anastomosis was approximately 25-30 min. The creatinine level was 90-80 μmol/L after surgery. The operative time of the four patients who underwent autotransplantation was 9.4-17.5 h. The times of venous and arterial anastomosis were 58-90 min and 35-48 min, respectively. The follow-up B-mode ultrasound after surgery showed good blood supply in the spared nephron. A renal graft was removed from one patient 6 months after surgery because of renal atrophy and dysfunction caused by poor blood supply. Five patients (two undergoing allografting and three undergoing autografting) completed the 12-month follow-up, and their renal graft function was good.

CONCLUSIONS

Extraperitoneal laparoscopic kidney transplantation, either allograft or autologous transplantation, is a safe and feasible procedure with a good chance of survival for the transplanted kidney. A customised cooling device is effective and practical during laparoscopic kidney transplantation.

Porcine cancer models: potential tools to enhance cancer drug trials

INTRODUCTION

The amount of time and money invested into cancer drug research, development, and clinical trials has continually increased over the past few decades. Despite record high cancer drug approval rates, cancer remains a leading cause of death. This suggests the need for more effective tools to help bring novel therapies to clinical practice in a timely manner.

AREAS COVERED

In this review, current issues associated with clinical trials are discussed, specifically focusing on poor accrual rates and time for trial completion. In addition, details regarding preclinical studies required before advancing to clinical trials are discussed, including advantages and limitations of current preclinical animal cancer models and their relevance to human cancer trials. Finally, new translational porcine cancer models (Oncopig Cancer Model (OCM)) are presented as potential co-clinical trial models.

EXPERT OPINION

In order to address issues impacting the poor success rate of oncology clinical trials, we propose the incorporation of the transformative OCM 'co-clinical trial' pathway into the cancer drug approval process. Due to the Oncopig's high homology to humans and similar tumor phenotypes, their utilization can provide improved preclinical prediction of both drug safety and efficacy prior to investing significant time and money in human clinical trials.

Feasibility of Laparoscopic Combined Para-Orthotopic Pancreas and Orthotopic Kidney Transplantation: Initial Research with a Pig Model

BACKGROUND The aim of this study was to investigate the feasibility of laparoscopic combined para-orthotopic pancreas and orthotopic kidney transplantation in a pig model. MATERIAL AND METHODS Twelve white female pigs, (4-5 months old, weight range 40-45 kg) were used as donors and recipients, and 6 laparoscopic-combined pancreas and kidney transplantations were performed. After bilateral nephrectomy, the pancreatic artery and vein were anastomosed to the right renal artery and vein, respectively, and the pancreatic fluid was diverted to the duodenum or jejunum. The renal artery and vein were anastomosed to the left renal artery and vein, respectively. The ureter (or kidney pelvis) was anastomosed to the left native ureter (or kidney pelvis). The data of the operations were recorded, and grafts were inspected at autopsy. RESULTS Four of the 6 recipient pigs underwent the entire procedure. The duodenum-to-duodenum anastomosis was unfinished in 1 case, and both the duodenum-to-duodenum and renal pelvis-to-pelvis anastomoses were left unperformed in another case. The mean recipient operative time was 429±43 minutes. The mean venous and arterial anastomotic times were 69±15 minutes and 37±18 minutes, respectively, for pancreas transplantation and 56±09 minutes and 42±06 minutes, respectively, for kidney transplantation. The time for renal pelvis-to-pelvis anastomosis was 56±13 minutes and for duodenum-to-duodenum anastomosis was 90±13 minutes. The mean blood loss for recipient pigs was 98±35 mL. An immediate viable blood supply was seen in the 4 pancreatic grafts and in the 5 kidney grafts during the operation by the appearance of a bright red color after revascularization. Five pancreatic grafts had autopsy-proven reliable artery anastomoses and 4 reliable vein anastomoses. All 6 kidney grafts had autopsy-proven reliable artery anastomoses; however, 1 had a vein anastomotic stricture. CONCLUSIONS Our study showed that laparoscopic-combined para-orthotopic pancreas and orthotopic kidney transplantation in pigs is surgically possible.

Robotic kidney autotransplantation in a porcine model: a procedure-specific training platform for the simulation of robotic intracorporeal vascular anastomosis

Robotic-assisted kidney transplantation (RKT) with the Da Vinci (Intuitive, USA) platform has been recently developed to improve outcomes by decreasing surgical site complications and morbidity, especially in obese patients. This potential paradigm shift in the surgical technique of kidney transplantation is performed in only a few centers. For wider adoption of this high stake complex operation, we aimed to develop a procedure-specific simulation platform in a porcine model for the training of robotic intracorporeal vascular anastomosis and evaluating vascular anastomoses patency. This paper describes the requirements and steps developed for the above training purpose. Over a series of four animal ethics' approved experiments, the technique of robotic-assisted laparoscopic autotransplantation of the kidney was developed in Amsterdam live pigs (60-70 kg). The surgery was based around the vascular anastomosis technique described by Menon et al. This non-survival porcine training model is targeted at transplant surgeons with robotic surgery experience. Under general anesthesia, each pig was placed in lateral decubitus position with the placement of one robotic camera port, two robotic 8 mm ports and one assistant port. Robotic docking over the pig posteriorly was performed. The training platform involved the following procedural steps. First, ipsilateral iliac vessel dissection was performed. Second, robotic-assisted laparoscopic donor nephrectomy was performed with in situ perfusion of the kidney with cold Hartmann's solution prior to complete division of the hilar vessels, ureter and kidney mobilization. Thirdly, the kidney was either kept in situ for orthotopic autotransplantation or mobilized to the pelvis and orientated for the vascular anastomosis, which was performed end to end or end to side after vessel loop clamping of the iliac vessels, respectively, using 6/0 Gore-Tex sutures. Following autotransplantation and release of vessel loops, perfusion of the graft was assessed using intraoperative indocyanine green imaging and monitoring urine output after unclamping. This training platform demonstrates adequate face and content validity. With practice, arterial anastomotic time could be improved, showing its construct validity. This porcine training model can be useful in providing training for robotic intracorporeal vascular anastomosis and may facilitate confident translation into a transplant human recipient.

Partial (two-thirds) nephrectomy in pigs: A comparison of three surgical approaches

Partial (2/3) nephrectomy can be performed via the laparoscopic, retroperitoneal, and transperitoneal approach. Outcomes of the three approaches were compared in this study. 2/3 nephrectomy were performed in 21 healthy Bama miniature pigs (mean bodyweight 20.59±2.78kg). Pigs were divided into three groups: those that underwent 2/3 nephrectomy via laparoscopy (LN group, n=7), the retroperitoneal approach (RN group, n=7), or the transperitoneal approach (TN group, n=7). We monitored pre- and postoperative physiologic parameters, blood cell count, and stress and renal function biomarkers. Differences among groups were analyzed. 2/3 nephrectomy was successfully performed in all pigs without any complications. Mean surgical time in the LN group (60.71±7.34min) and the TN group (58.57±4.72min) was significantly longer than that in the RN group (41.14±5.33min). Warm ischemia in the LN group (38±7.57min) was significantly longer than that in the TN group (28.86±4.53min), which was significantly longer than that in the RN group (17.86±2.34min). The postoperative serum concentration of C-reactive protein in the TN group was significantly higher than that in the LN group (p<0.05). So retroperitoneal approach was best choice in case of bilateral renal lesion resulted in shortest ischemia time, and laparoscopic partial nephrectomy should be the primary choice in majority situations resulted in less body stress, smaller surgical incisions and less blood loss.

Novel surgical techniques, regenerative medicine, tissue engineering and innovative immunosuppression in kidney transplantation

On the 60th anniversary of the first successfully performed renal transplantation, we summarize the historical, current and potential future status of kidney transplantation. We discuss three different aspects with a potential significant influence on kidney transplantation progress: the development of surgical techniques, the influence of regenerative medicine and tissue engineering, and changes in immunosuppression. We evaluate the standard open surgical procedures with modern techniques and compare them to less invasive videoscopic as well as robotic techniques. The role of tissue engineering and regenerative medicine as a potential method for future kidney regeneration or replacement and the interesting search for novel solutions in the field of immunosuppression will be discussed. After 60 years since the first successfully performed kidney transplantation, we can conclude that the greatest achievements are associated with the development of surgical techniques and with planned systemic immunosuppression.

Heterotopic Renal Autotransplantation in a Porcine Model: A Step-by-Step Protocol

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.

Swine model in transplant research: Review of anaesthesia and perioperative management

Pigs are one of most common animal species to be used in biomedical models due to their many anatomical visceral similarities with humans, particularly with regards to transplantation. Despite this use, in many of the researches in which pigs are selected for transplantation, the anaesthesia used is an adaptation of human anaesthesia and presents some limitations such as a reduced analgesia a limited control in perioperative period. In this review we show some of the most important conditions in the preanaesthetic management and of swine as well as we review of anaesthetic protocols for the most common types of swine model of transplantation.

Catheterization of the urethra in female pigs

Female pigs are commonly utilized as an animal model for biomedical research and require urethral catheterization. Sixteen pigs were anaesthetized for research purposes and required the placement of a urethral catheter. Post-mortem examination of the vaginas revealed the urethral opening to be consistently halfway from the mucocutaneous junction of the vulva to the cervix. A shallow diverticulum was also observed on the ventral floor of the urethral opening. To optimize conditions for success the pig should be carefully positioned supine, a vaginal speculum and light source should be used, the pig should be adequately anaesthetized, and the anatomy of the vagina should be reviewed.

Laparoscopic kidney transplant by extra peritoneal approach: the safe transition from laboratory to the clinic

The aim of this study is to develop a novel laparoscopic surgery by extra-peritoneal approach for kidney transplant and pave the way of safe transition from laboratory to the clinic. The study was established to explore the feasibility and safety of human laparoscopic kidney transplant. The experiment was first conducted on the deceased animals, then live animals and human cavader before human kidney transplant was approved. The study patient was a 49-year-old male who received the kidney for laparoscopic kidney transplant by extra-peritoneal approach. The control patient received the contralateral kidney for open kidney transplant. The estimated blood loss was minimal during surgery. Both kidneys experienced delayed graft function but the kidneys started function on Day 6 postoperation. The analgesia consumption was significantly less in the study patient. There is no surgical complication during 6-month follow-up. This study has developed a new technique for laparoscopic kidney transplant by extra-peritoneal approach. It has retained the advantages of open kidney transplant, which allows the graft located in the extra-peritoneal space without violating peritoneum. This study has also paved the way of safe transition for a novel laparoscopic surgery from laboratory to the clinic.