Allograft nephrectomy: what is the best surgical technique?

Ischemia-Reperfusion Injury in Kidney Transplantation: Mechanisms and Potential Therapeutic Targets

Kidney transplantation offers a longer life expectancy and a better quality of life than dialysis to patients with end-stage kidney disease. Ischemia-reperfusion injury (IRI) is thought to be a cornerstone in delayed or reduced graft function and increases the risk of rejection by triggering the immunogenicity of the organ. IRI is an unavoidable event that happens when the blood supply is temporarily reduced and then restored to an organ. IRI is the result of several biological pathways, such as transcriptional reprogramming, apoptosis and necrosis, innate and adaptive immune responses, and endothelial dysfunction. Tubular cells mostly depend on fatty acid (FA) β-oxidation for energy production since more ATP molecules are yielded per substrate molecule than glucose oxidation. Upon ischemia-reperfusion damage, the innate and adaptive immune system activates to achieve tissue clearance and repair. Several cells, cytokines, enzymes, receptors, and ligands are known to take part in these events. The complement cascade might start even before organ procurement in deceased donors. However, additional experimental and clinical data are required to better understand the pathogenic events that take place during this complex process.

Allograft nephrectomy vs. no nephrectomy for failed renal transplants

The role of allograft nephrectomy (AN) in failed renal transplants is a topic of debate, owing to controversial results reported in the literature and the fact that most of the studies are limited by a retrospective design and small numbers of participants. Allograft nephrectomy is most likely of benefit in the patient with recurrent allograft intolerance syndrome (AIS) following pulse steroids. Immunosuppression weaning in the presence of clinical signs related to a chronic inflammatory state is also reasonable grounds to pursue AN. Studies are mainly inconclusive but suggest that AN has no overall benefit for allograft survival after retransplant. This topic is still of interest in the transplant field and is particularly relevant for patients who are likely to require retransplantation within their lifetime. Further assessment is needed in the form of randomized controlled trials that control for various AN indications and immunosuppression regimens, and have clearly defined survival outcomes.

Graft Failure after Uterus Transplantation in 16 Recipients: A Review

Uterus transplantation (UTx) is now an alternative to surrogacy and adoption for women with uterine factor infertility to have children; however, there are still unresolved clinical and technical issues. One of these is that the graft failure rate after transplantation is somewhat higher than that of other life-saving organ transplants, which is a critical concern. Herein, we summarize the details of 16 graft failures after UTx with living or deceased donors using the published literature in order to learn from these negative outcomes. To date, the main causes of graft failure are vascular factors (arterial and/or venous thrombosis, atherosclerosis, and poor perfusion). Many recipients with thrombosis develop graft failure within one month of surgery. Therefore, it is necessary to devise a safe and stable surgical technique with higher success rates for further development in the UTx field.

Transplant Nephrectomy: Current Concepts

Kidney transplantation is the gold standard treatment option for patients with endstage kidney disease. As the number of waitlisted patients increases, the gap between supply and demand for suitable donor kidneys keeps widening. The adoption of novel strategies that expand the donor pool has attenuated this issue to a certain degree, and this has led to a progressive increase in the number of annual transplants performed. As transplanted kidneys have a finite lifespan, there is a reciprocal rise in the number of patients who return to dialysis once their allograft fails. The clinicians involved in the management of such patients are left with the problem of managing the nonfunctioning allograft. The decision to undertake transplant nephrectomy (TN) in these patients is not straightforward. Allograft nephrectomy is a procedure that is associated with significant morbidity and mortality. It will have implications for the outcomes of the subsequent transplant. In this review, we aimed to compressively discuss the indications, techniques, and outcomes of TN, which is an integral component of the management of a failing allograft.

Novel Insights into the Molecular Mechanisms of Ischemia/Reperfusion Injury in Kidney Transplantation

Ischemia reperfusion injury (IRI) is one of the most important mechanisms involved in delayed or reduced graft function after kidney transplantation. It is a complex pathophysiological process, followed by a pro-inflammatory response that enhances the immunogenicity of the graft and the risk of acute rejection. Many biologic processes are involved in its development, such as transcriptional reprogramming, the activation of apoptosis and cell death, endothelial dysfunction and the activation of the innate and adaptive immune response. Recent evidence has highlighted the importance of complement activation in IRI cascade, which expresses a pleiotropic action on tubular cells, on vascular cells (pericytes and endothelial cells) and on immune system cells. The effects of IRI in the long term lead to interstitial fibrosis and tubular atrophy, which contribute to chronic graft dysfunction and subsequently graft failure. Furthermore, several metabolic alterations occur upon IRI. Metabolomic analyses of IRI detected a “metabolic profile” of this process, in order to identify novel biomarkers that may potentially be useful for both early diagnosis and monitoring the therapeutic response. The aim of this review is to update the most relevant molecular mechanisms underlying IRI, and also to discuss potential therapeutic targets in future clinical practice.

Clinical features of irreversible rejection after allogeneic uterus transplantation in cynomolgus macaques

Uterus transplantation (UTx) is a potential option for women with uterine factor infertility to have a child. The clinical features indicating irreversible rejection of the uterus are unknown. In our experimental series of allogeneic UTx in cynomolgus macaques, six female macaques were retrospectively examined, which were unresponsive to treatment with immunosuppressants (i.e. irreversible rejection). Clinical features including general condition, hematology, uterine size, indocyanine green (ICG) fluorescence imaging by laparotomy, and histopathological findings of the removed uterus were evaluated. In all cases, general condition was good at the time of diagnosis of irreversible rejection and thereafter. Laboratory evaluation showed temporary increases in white blood cells, lactate dehydrogenase and C-reactive protein, then these levels tended to decrease gradually. In transabdominal ultrasonography, the uterus showed time-dependent shrinkage after transient swelling at the time of diagnosis of irreversible rejection. In laparotomy, a whitish transplanted uterus was observed and enhancement of the transplanted uterus was absent in ICG fluorescence imaging. Histopathological findings in each removed uterus showed hyalinized fibrosis, endometrial deficit, lymphocytic infiltration and vasculitis. These findings suggest that uterine transplantation rejection is not fatal, in contrast to rejection of life-supporting organs. Since the transplanted uterus with irreversible rejection atrophies naturally, hysterectomy may be unnecessary.

Transplant nephrectomy after graft failure: is it so risky? Impact on morbidity, mortality and alloimmunization

PURPOSE

To determine the impact of transplant nephrectomy on morbidity and mortality and HLA immunization.

METHODS

All patients who underwent transplant nephrectomy in our centre between 2000 and 2016 were included in this study. A total of 2822 renal transplantations and 180 transplant nephrectomies were performed during this period.

RESULTS

The indications for transplant nephrectomy were graft intolerance syndrome: 47.2%, sepsis: 22.2%, vascular thrombosis: 15.5%, tumour: 8.3% and other 6.8%. Transplant nephrectomies were performed via an intracapsular approach in 61.7% of cases. The blood transfusion rate was 50%, the morbidity rate was 38% and the mortality rate was 3%. Transplant nephrectomies more than 12 months after renal transplant failure were associated with more complications (p = 0.006). Transfusions in the context of transplant nephrectomy had no significant impact on alloimmunization.

CONCLUSION

The risk of bleeding, and therefore of transfusion, constitutes the major challenge of this surgery in patients eligible for retransplantation. Even if transfusions in this context of transplant nephrectomy had no significant impact on alloimmunization, this high-risk surgery, whenever possible, must be performed electively in a well-prepared patient.

Pushing Boundaries: Robotic Nephrectomy of an Auto-transplanted Kidney for Recurrent Renal Cell Carcinoma

Advances in robotic technology continue to expand the boundaries of minimally invasive approaches in transplant surgery. A single report has previously described the use of the robotic approach in transplant nephrectomy for a failed allograft. Our objective is to describe our technique and experience for the first reported robotic nephrectomy of an auto-transplanted solitary kidney for a recurrence of renal cell carcinoma (RCC). We highlight technical considerations during allograft mobilization and hilum dissection with the additional demands of a previously operated auto-transplant kidney.

Graft nephrectomy in children

Kidney transplantation is recognised as the gold standard treatment of end-stage renal disease in most children, with excellent graft survival rates. When graft failure occurs, renal transplant recipients (RTRs) have the option of removal of the transplant (graft nephrectomy [GN]), or leaving the failed transplant in situ. The aims of this review are to discuss the indications for GN, surgical techniques, outcomes after GN (including risks of allosensitisation and the impact on subsequent transplants), and the possible role of routine GN in the asymptomatic RTR with a failed renal allograft. Literature in both the pediatric and adult renal transplant fields is reviewed. We also discuss how future research in this area could advance our knowledge of which patients to select for GN, and the most appropriate surgical approach.