Incidence, etiology, and significance of acute kidney injury in the early post-kidney transplant period

Acute post-renal kidney graft dysfunction due to cytomegalovirus-positive nephrogenic adenoma-case report and review of the literature

Tissue-invasive cytomegalovirus (CMV) disease represents a well-recognized complication after kidney transplantation. However, direct involvement of the urogenital tract and CMV-ureteritis occur less frequently. Nephrogenic adenomas are benign lesions of the urinary tract preferentially reported in kidney transplant recipients. We herein report a second case of a 33-year-old male kidney transplant recipient with acute post-renal allograft dysfunction due to CMV-positive ureteral nephrogenic adenoma. A causal connection might be suspected but remains to be proven.

Acute Kidney Injury in Kidney Transplant Patients in Intensive Care Unit: From Pathogenesis to Clinical Management

Kidney transplantation is the first-choice treatment for end-stage renal disease (ESRD). Kidney transplant recipients (KTRs) are at higher risk of experiencing a life-threatening event requiring intensive care unit (ICU) admission, mainly in the late post-transplant period (more than 6 months after transplantation). Urosepsis and bloodstream infections account for almost half of ICU admissions in this population; in addition, potential side effects related to immunosuppressive treatment should be accounted for cytotoxic and ischemic changes induced by calcineurin inhibitor (CNI), sirolimus/CNI-induced thrombotic microangiopathy and posterior reversible encephalopathy syndrome. Throughout the ICU stay, Acute Kidney Injury (AKI) incidence is common and ranges from 10% to 80%, and up to 40% will require renal replacement therapy. In-hospital mortality can reach 30% and correlates with acute illness severity and admission diagnosis. Graft survival is subordinated to baseline estimated glomerular filtration rate (eGFR), clinical presentation, disease severity and potential drug nephrotoxicity. The present review aims to define the impact of AKI events on short- and long-term outcomes in KTRs, focusing on the epidemiologic data regarding AKI incidence in this subpopulation; the pathophysiological mechanisms underlying AKI development and potential AKI biomarkers in kidney transplantation, graft and patients' outcomes; the current diagnostic work up and management of AKI; and the modulation of immunosuppression in ICU-admitted KTRs.

Fluid overload and renal function in children after living-donor renal transplantation: a single-center retrospective analysis

BACKGROUND

We aimed to compare renal function after kidney transplantation in children who were treated with higher vs. lower fluid volumes.

METHODS

A retrospective analysis of 81 living-donor renal transplantation pediatric patients was performed between the years 2007 and 2018. We analyzed associations of the decrease in serum creatinine (delta creatinine) with fluid balance, central venous pressure (CVP), pulmonary congestion, mean arterial pressure (MAP), and MAP-CVP percentiles in the first 3 postoperative days. After correcting creatinine for fluid overload, we also assessed associations of these variables with the above parameters. Finally, we evaluated the association between delta creatinine and estimated glomerular filtration rate (eGFR) at 3 months follow-up.

RESULTS

Both delta creatinine and delta-corrected creatinine were found to be associated with pulmonary congestion on the second and third postoperative days (p < 0.02). In addition, trends for positive correlations were found of delta creatinine with fluid balance/kg (p = 0.07), and of delta-corrected creatinine with fluid balance/kg and CVP (p = 0.06-0.07) on the second postoperative day. An association was also demonstrated between the accumulated fluid balance of the first 2 days and eGFR at 3 months after transplantation (p = 0.03).

CONCLUSIONS

An association was demonstrated between indices of fluid overload, >80 ml/kg, and greater improvement in renal function.

IMPACT

There is no consensus regarding the optimal fluid treatment after pediatric renal transplantation. In our cohort, indices of fluid overload were associated with better renal function immediately after the transplantation and 3 months thereafter. Fluid overload after living-donor renal transplantation in children may have short- and long-term benefits on renal function.

Acute kidney injury in renal transplant recipients undergoing cardiac surgery

BACKGROUND

Acute kidney injury (AKI) is a key risk factor for chronic kidney disease in the general population, but has not been investigated in detail among renal transplant recipients (RTRs). We investigated the incidence, severity and risk factors for AKI following cardiac surgery among RTRs compared with non-RTRs with otherwise similar clinical characteristics.

METHODS

We conducted a retrospective cohort study of RTRs (n = 83) and non-RTRs (n = 83) who underwent cardiac surgery at two major academic medical centers. Non-RTRs were matched 1:1 to RTRs by age, preoperative (preop) estimated glomerular filtration rate and type of cardiac surgery. We defined AKI according to Kidney Disease: Improving Global Outcomes criteria.

RESULTS

RTRs had a higher rate of AKI following cardiac surgery compared with non-RTRs [46% versus 28%; adjusted odds ratio 2.77 (95% confidence interval 1.36-5.64)]. Among RTRs, deceased donor (DD) versus living donor (LD) status, as well as higher versus lower preop calcineurin inhibitor (CNI) trough levels, were associated with higher rates of AKI (57% versus 33% among DD-RTRs versus LD-RTRs; P = 0.047; 73% versus 36% among RTRs with higher versus lower CNI trough levels, P = 0.02). The combination of both risk factors (DD status and higher CNI trough level) had an additive effect (88% AKI incidence among patients with both risk factors versus 25% incidence among RTRs with neither risk factor, P = 0.004).

CONCLUSIONS

RTRs have a higher risk of AKI following cardiac surgery compared with non-RTRs with otherwise similar characteristics. Among RTRs, DD-RTRs and those with higher preop CNI trough levels are at the highest risk.

Using electronic AKI alerts to define the epidemiology of acute kidney injury in renal transplants

Background

Little is known regarding the impact of acute kidney injury (AKI) on renal transplant outcome. Our aim was to define the incidence and outcome of AKI in renal transplant patients using data collected from a national AKI electronic alert system

Methods

The study represents a prospective national cohort study collecting data on 1224 renal transplants recipients with a functioning renal transplant, between April 2015 and March 2019.

Results

Four hundred forty patients experienced at least one episode of AKI giving an incidence rate of 35.4%. Sixty-four point seven% of episodes were AKI stage 1, 7.3% AKI stage 2 and 28% AKI stage 3. Only 6.2% of episodes occurred in the context of rejection. Forty-three point five% of AKI episodes were associated with sepsis. AKI was associated with pre-existing renal dysfunction, and a primary renal diagnosis of diabetic nephropathy. AKI was more prevalent in recipients from a donor after cardiac death (26.4% vs. 21.4%, p < 0.05) compared to the non-AKI cohort. Following AKI, 30-day mortality was 19.8% and overall mortality was 34.8%, compared to 8.4% in the non AKI cohort (RR 4.06, 95% CI 3.1–5.3, p < 0.001). Graft survival (GS), and death censored graft survival (DCGS) censored at 4 years, in the AKI cohort were significantly lower than in the non AKI group (p < 0.0001 for GS and DCGS).

Conclusion

The study provides a detailed characterisation of AKI in renal transplant recipients highlighting its significant negative impact on patient and graft survival.

Acute Kidney Injury and Long-Term Risk for Cardiovascular Events in Patients after Kidney Transplantation

BACKGROUND

Acute kidney injury (AKI) was found to be associated with an increased risk of major adverse cardiovascular events (MACE) in the general population. Patients after kidney transplantation are prone to AKI events and are also at an increased risk of cardiovascular (CV) disease. The association between AKI and MACE in kidney transplant patients is yet to be studied.

METHODS

This retrospective single-center cohort study reviewed 416 adult renal allograft recipients transplanted between 2005 and 2010. AKI events were recorded starting 2 weeks after transplantation, or following discharge with a functioning graft. AKI was defined, according to the KDIGO criteria. The primary outcome was the composite of MACE starting 6 months after transplantation and all-cause mortality. For survival analysis, we used univariate and multivariate time varying Cox proportional hazard model.

RESULTS

One hundred and twenty-four patients (29.8%) had at least one episode of AKI. During the median follow-up time of 7.2 years (interquartile range 4.3-9.1), 144 outcome events occurred. By time varying Cox regression analysis, AKI was associated with an increased rate of CV outcomes or death (hazard ratio [HR] 1.96, 95% CI 1.36-2.81, p < 0.001), and the association remained significant by multivariate adjusted model (HR 1.76, 95% CI 1.18-2.63, p = 0.005). As for the different components of MACE, all-cause mortality and CV mortality were the only outcomes that were significantly associated with AKI. No interaction between AKI timing and MACE was found.

CONCLUSION

AKI in kidney transplant recipient is associated with an increased risk of CV disease.

Association of the combination of time-weighted variability of tacrolimus blood level and exposure to low drug levels with graft survival after kidney transplantation

Background

The variability of tacrolimus blood levels has been shown to be associated with inferior graft survival. However, the effect of variability during the early post-transplantation period has not been evaluated. We sought to evaluate the association between time-weighted variability in the early post-transplantation period and graft survival. We also explored the interaction between drug level variability and exposure to inadequate drug levels.

Methods

This retrospective cohort study included all patients who underwent kidney transplantation in the Rabin Medical Center and were treated with tacrolimus. Time-weighted coefficient of variability (TWCV) was defined as time-weighted standard deviation divided by the mean drug level. Univariate and multivariate Cox proportional hazard model was used with the primary outcome of patients and graft survival.

Results

The study population included 803 patients who underwent kidney transplantation between 1 January 2000 and 29 September 2013. The high tertile of TWCV of tacrolimus blood levels was associated with reduced graft survival by univariate and multivariate analyses [hazard ratio (HR) 1.69, 95% confidence interval (CI) 1.14-2.53, P = 0.01 and HR 1.74, 95% CI 1.14-2.63, P = 0.01, respectively]. The interaction between high TWCV and exposure to inadequately low drug levels was significantly associated with reduced survival (P = 0.004), while the interaction between TWCV and high drug blood levels was not. One hundred and thirty patients (16.2%) had the combination of high TWCV and exposure to low drug values (<5 ng/mL). These patients had reduced graft survival by univariate and multivariate analyses (HR 2.42, 95% CI 1.57-3.74, P < 0.001 and HR 2.6, 95% CI 1.65-4.11, P < 0.001, respectively).

Conclusions

The combination of high TWCV and exposure to low drug levels might identify high-risk patients in the early post-transplantation period.

Supplementing diet with Manitoba lingonberry juice reduces kidney ischemia-reperfusion injury

BACKGROUND

Lingonberry (Vaccinium vitis-idaea L.) contains high levels of anthocyanins which are bioavailable in the kidney and may be protective against ischemia-reperfusion (IR)-induced acute kidney injury. This study investigated the effect of lingonberry juice on the IR-induced stress-activated signalling pathway and inflammatory response in the kidney.

RESULTS

Sprague-Dawley rats subjected to kidney IR had significantly impaired kidney function, with increased activation of the JNK signalling pathway and increased inflammatory response, measured using a multiplex panel containing an extensive array of inflammatory biomarkers. In rats fed 1 mL lingonberry juice daily for 3 weeks prior to IR, kidney function was protected and attenuation of inflammatory response and JNK signalling was reflected in the reduction of the measured biomarkers. In vitro results in cultured HK-2 cells confirmed that lingonberry anthocyanins reduced JNK signalling and inflammatory gene expression after IR.

CONCLUSION

This study shows, for the first time, that daily supplementation with lingonberry juice may protect against loss of kidney function induced by IR injury by modulating JNK signalling and inhibiting the subsequent inflammatory response. © 2017 Her Majesty the Queen in Right of Canada. Journal of the Science of Food and Agriculture © 2017 Society of Chemical Industry.

Necroptosis in acute kidney injury: a shedding light

Acute kidney injury (AKI) is a common and severe clinical condition with a heavy healthy burden around the world. In spite of supportive therapies, the mortality associated with AKI remains high. Our limited understanding of the complex cell death mechanism in the process of AKI impedes the development of desirable therapeutics. Necroptosis is a recently identified novel form of cell death contributing to numerable diseases and tissue damages. Increasing evidence has suggested that necroptosis has an important role in the pathogenesis of various types of AKI. Therefore, we present here the signaling pathways and main regulators of necroptosis that are potential candidate for therapeutic strategies. Moreover, we emphasize on the potential role and corresponding mechanisms of necroptosis in AKI based on recent advances, and also discuss the possible therapeutic regimens based on manipulating necroptosis. Taken together, the progress in this field sheds new light into the prevention and management of AKI in clinical practice.