Renal transplantation in recipients over 65 years old

Aging aggravated liver ischemia and reperfusion injury by promoting STING-mediated NLRP3 activation in macrophages

Although aggravated liver injury has been reported in aged livers post‐ischemia and reperfusion (IR), the underlying mechanism of innate immune activation of aged macrophages is not well understood. Here, we investigated whether and how Stimulator of interferon genes (STING) signaling regulated macrophage proinflammatory activation and liver IR injury. Mice were subjected to hepatic IR in vivo. Macrophages isolated from IR‐stressed livers and bone marrow‐derived macrophages (BMDMs) from young and aged mice were used for in vitro studies. Enhanced nucleotide‐binding domain and leucine‐rich repeat containing protein 3 (NLRP3) activation was found in both livers and macrophages of aged mice post‐IR. NLRP3 knockdown in macrophages inhibited intrahepatic inflammation and liver injury in both young and aged mice. Interestingly, enhanced activation of the STING/ TANK‐binding kinase 1 (TBK1) signaling pathway was observed in aged macrophages post‐IR and mitochondria DNA (mtDNA) stimulation. STING suppression blocked over‐activation of NLRP3 signaling and excessive secretion of proinflammatory cytokines/chemokines in the mtDNA‐stimulated BMDMs from aged mice. More importantly, STING knockdown in macrophages abrogated the detrimental role of aging in aggravating liver IR injury and intrahepatic inflammation. Finally, peripheral blood from the recipients undergoing liver transplantation was collected and analyzed. The results showed that the elderly recipients had much higher levels of TNF‐α, IL‐6, IL‐1β, and IL‐18 post‐transplantation, indicating increased NLRP3 activation in lR‐stressed livers of elderly recipients. In summary, our study demonstrated that the STING‐NLRP3 axis was critical for the proinflammatory response of aged macrophages and would be a novel therapeutic target to reduce IR injury in elderly patients.

Prognostic Value of Aortoiliac Calcification Score in Kidney Transplantation Recipients

BACKGROUND

Kidney recipients are increasingly older with arterial disease and extended arterial calcifications. In a kidney transplantation population, the prognosis value of aortic and iliac calcifications remains poorly explored. We aimed to assess the impact of pretransplantation aortoiliac vascular calcifications on patients, grafts survival, and cardiovascular events.

METHODS

This retrospective study included kidney transplantation patients from 2006 to 2012 for whom we had available presurgery abdominal computed tomography results (n = 100). We designed a score to quantify aortoiliac calcifications. Primary end points were patient and graft survival. Secondary end points were renal function and cardiovascular morbidity. Predictive performances of calcification score were assessed using area under receiver-operating characteristic curves. Patients were classified in quartiles depending on global calcium score value.

RESULTS

The cumulated rate of death and graft loss was 13% with no significant differences for survival between quartiles. No significant difference was observed in renal function (P = 0.4). Seventeen cardiovascular events were registered with a significant correlation between calcium score elevation and need of cardiovascular surgery during the follow-up (P = 0.01). Global calcium score had a predictive value of 74.5% (95% confidence interval 0.62-0.87) with 71% sensitivity and 73% specificity.

CONCLUSIONS

Aortoiliac calcifications do not decrease patient and graft survival. High calcium score predict cardiovascular events and procedures during the follow-up.

Impact of ultrasound examination shortly after kidney transplantation

Background

Ultrasound is routinely performed at our transplant unit within the first 48 h of kidney transplantation (KTX). The objective of this study was to evaluate the association of ultrasound results and, in particular, elevated resistance indices (RIs) with the occurrence of surgical complications and allograft outcomes.

Methods

The study included all kidney allograft recipients undergoing transplantation at our center between January 2010 and December 2011 (N = 329). Ultrasound examination was performed on 315 recipients (95.7%).

Results

Delayed graft function was more common in subjects with a high RI (≥0.7) than in patients with an RI < 0.7 (47.2 vs. 28.2%; p = 0.032). A lack of arterial signal was detected in eight patients (2.5%), of whom five had a vascular complication that required surgical therapy. In 12 patients (3.8%), RI was 1 without any other signs of vascular impairment. Even though such values can be a sign of venous thrombosis, no case was observed in any of these patients.

Conclusions

The results of our study suggest that ultrasound evaluation of the transplanted kidney shortly after transplantation is a valuable tool not only for detecting vascular complications but also as a predictor of graft outcome regarding delayed graft function.

Renal Transplantation in Recipients Older Than 65 Years: Retrospective Analysis of the Results of a 4-year (2008-2012) Experience

BACKGROUND

We analyze the results of renal transplantation among recipients older than 65 years old over a 4-year period (2008-2012) from a single renal transplantation unit and compare results with younger recipients.

METHODS

We retrospectively analyzed the outcomes of 2018 renal transplantations performed between November 2008 and December 2012. The χ(2) test was used for the comparison of categorical data, and the Student t test was used for the analysis of continuous variables. Patient and graft cumulative actuarial survivals were calculated using the Kaplan-Meier analysis and we tested for differences with the Mantel-Cox log-rank test.

RESULTS

Seventy-five (3.7%) recipients were aged ≥ 65 years with a median age of 68 (range, 65 to 82) years. Actuarial graft survivals at 1, 2, and 3 years were 93.8%, 92.5%, and 90.3%, respectively, for the <65 group and 89.7%, 88.1%, and 83.1%, respectively, for the ≥ 65 group (P < .03). Actuarial patient survivals at 1, 2, and 3 years were 96.3%, 95.5%, and 94.7%, respectively, for the younger and 91.8%, 90.2%, and 88%, respectively, for the older samples (P < .03). When graft survival was censored for patient death with a functioning kidney at 1, 2, and 3 years, the results were similar between groups with 95.5%, 94%, and 92.8%, respectively, for recipients aged <65 years and 94.7%, 89.2%, and 89.2%, respectively, for recipients aged ≥ 65 years (P = .213).

CONCLUSIONS

Our results showed that renal transplantation in selected patients older than 65 years was associated with good outcomes; this indicates that it seems safe and effective to treat end-stage renal disease in the elderly knowing there are acceptable rates of graft and patient survival.

Kidney transplantation and the ageing immune system

The world population is rapidly growing and ageing at a pace that is projected to continue for at least three decades. This shift towards an older populace has invariably increased the number of individuals with diseases related to ageing, such as chronic kidney disease. The increase in chronic kidney disease is associated with a growing number of elderly patients receiving kidney transplants. Understanding how the immune system changes with increasing age will help to define the risks of rejection and infection in the elderly population and will focus attention on the need for individualized immunosuppression for patients in this age group. This Review addresses what is currently known about ageing and the immune system, highlighting age-related changes that affect the outcome of transplantation in elderly individuals. The need for new strategies to improve outcomes in this growing population of elderly renal transplant recipients is also emphasized.