Renal comorbidity after solid organ and stem cell transplantation

LXA4 protected mice from renal ischemia/reperfusion injury by promoting IRG1/Nrf2 and IRAK-M-TRAF6 signal pathways

Excessive inflammatory response and increased oxidative stress play an essential role in the pathophysiology of ischemia/reperfusion (I/R)-induced acute kidney injury (IRI-AKI). Emerging evidence suggests that lipoxin A4 (LXA4), as an endogenous negative regulator in inflammation, can ameliorate several I/R injuries. However, the mechanisms and effects of LXA4 on IRI-AKI remain unknown. In this study, A bilateral renal I/R mouse model was used to evaluate the role of LXA4 in wild-type, IRG1 knockout, and IRAK-M knockout mice. Our results showed that LXA4, as well as 5-LOX and ALXR, were quickly induced, and subsequently decreased by renal I/R. LXA4 pretreatment improved renal I/R-induced renal function impairment and renal damage and inhibited inflammatory responses and oxidative stresses in mice kidneys. Notably, LXA4 inhibited I/R-induced the activation of TLR4 signal pathway including decreased phosphorylation of TAK1, p36, and p65, but did not affect TLR4 and p-IRAK-1. The analysis of transcriptomic sequencing data and immunoblotting suggested that innate immune signal molecules interleukin-1 receptor-associated kinase-M (IRAK-M) and immunoresponsive gene 1 (IRG1) might be the key targets of LXA4. Further, the knockout of IRG1 or IRAK-M abolished the beneficial effects of LXA4 on IRI-AKI. In addition, IRG1 deficiency reversed the up-regulation of IRAK-M by LXA4, while IRAK-M knockout had no impact on the IRG1 expression, indicating that IRAK-M is a downstream molecule of IRG1. Mechanistically, we found that LXA4-promoted IRG1-itaconate not only enhanced Nrf2 activation and increased HO-1 and NQO1, but also upregulated IRAK-M, which interacted with TRAF6 by competing with IRAK-1, resulting in deactivation of TLR4 downstream signal in IRI-AKI. These data suggested that LXA4 protected against IRI-AKI via promoting IRG1/Itaconate-Nrf2 and IRAK-M-TRAF6 signaling pathways, providing the rationale for a novel strategy for preventing and treating IRI-AKI.

Acute kidney injury in autologous hematopoietic stem cell transplant for patients with lymphoma - KDIGO classification with creatinine and urinary output criteria: a cohort analysis

Eligibility and indication for autologous hematopoietic stem cell transplantation (HSCT) in patients with lymphoma are increasing. Acute kidney injury (AKI) is a known complication of HSCT with studies including a miscellaneous of hematological diagnoses and using different definitions of AKI. We aimed to evaluate incidence, risk factors and prognostic impact of AKI post-HSCT in patients with lymphoma submitted to autologous HSCT using the KDIGO classification with both serum creatinine and urinary output criteria. We performed a single-center retrospective cohort study including patients with lymphoma admitted for autologous HSCT. We used survival analysis with competing risks to evaluate cumulative incidence of AKI, AKI risk factors and AKI impact on disease-free survival. We used Cox regression for impact of AKI on overall survival. We used backward stepwise regression to create multivariable models. A total of 115 patients were included. Cumulative incidence of AKI: 63.7% 100 d post-HSCT. First diagnosis criteria: creatinine in 54.8%, urinary output in 41.1% and both in 4.1%. AKI highest stage: 1 in 57.5%, 2 in 17.8% and 3 in 24.7%. Variables independently associated with higher incidence of AKI were: use of nephrotoxic drugs (HR: 2.87, 95% CI: 1.07-7.65; p = 0.035), mucositis (HR: 1.95, 95% CI: 1.16-3.29; p = 0.012) and shock (HR: 2.63, 95% CI: 1.19-5.85; p = 0.017). Moderate to severe AKI was independently associated with lower overall survival (HR: 2.04, 95% CI: 1.06-3.94; p = 0.033). No association with relapse nor progression to chronic kidney disease (CKD) was found. AKI affects almost two thirds of patients with lymphomas submitted to autologous HSCT. Nephrotoxic drugs, mucositis and shock are important independent AKI risk factors. More than one third of AKI episodes are moderate to severe and these are associated with lower overall survival.

Predictive Risk Score for Acute Kidney Injury in Hematopoietic Stem Cell Transplant

Hematopoietic stem cell transplant (HSCT) is an important treatment option for hematologic malignancies. Acute kidney injury (AKI) is a common complication in HSCTs and is related to worse outcomes. We aimed to create a predictive risk score for AKI in HSCT considering variables available at the time of the transplant. We performed a retrospective cohort study. AKI was defined by the KDIGO classification using creatinine and urinary output criteria. We used survival analysis with competing events. Continuous variables were dichotomized according to the Liu index. A multivariable analysis was performed with a backward stepwise regression. Harrel's C-Statistic was used to evaluate the performance of the model. Points were attributed considering the nearest integer of two times each covariate's hazard ratio. The Liu index was used to establish the optimal cut-off. We included 422 patients undergoing autologous (61.1%) or allogeneic (38.9%) HSCTs for multiple myeloma (33.9%), lymphoma (27.3%), and leukemia (38.8%). AKI cumulative incidence was 59.1%. Variables eligible for the final score were: hematopoietic cell transplant comorbidity index ≥2 (HR: 1.47, 95% CI: 1.08-2.006; p = 0.013), chronic kidney disease (HR: 2.10, 95% CI: 1.31-3.36; p = 0.002), lymphoma or leukemia (HR: 1.69, 95% CI: 1.26-2.25; p < 0.001) and platelet-to-lymphocyte ratio > 171.9 (HR: 1.43, 95% CI: 1.10-1.86; p = 0.008). This is the first predictive risk score for AKI in patients undergoing HSCTs and the first study where the platelet-to-lymphocyte ratio is independently associated with AKI.

Kidney disease in non-kidney solid organ transplantation

Kidney disease after non-kidney solid organ transplantation (NKSOT) is a common post-transplant complication associated with deleterious outcomes. Kidney disease, both acute kidney injury and chronic kidney disease (CKD) alike, emanates from multifactorial, summative pre-, peri- and post-transplant events. Several factors leading to kidney disease are shared amongst solid organ transplantation in addition to distinct mechanisms unique to individual transplant types. The aim of this review is to summarize the current literature describing kidney disease in NKSOT. We conducted a narrative review of pertinent studies on the subject, limiting our search to full text studies in the English language. Kidney disease after NKSOT is prevalent, particularly in intestinal and lung transplantation. Management strategies in the peri-operative and post-transplant periods including proteinuria management, calcineurin-inhibitor minimization/ sparing approaches, and nephrology referral can counteract CKD progression and/or aid in subsequent kidney after solid organ transplantation. Kidney disease after NKSOT is an important consideration in organ allocation practices, ethics of transplantation. Kidney disease after SOT is an incipient condition demanding further inquiry. While some truths have been revealed about this chronic disease, as we have aimed to describe in this review, continued multidisciplinary efforts are needed more than ever to combat this threat to patient and allograft survival.

Risk of Renal Dysfunction Following Heart Transplantation in Patients Bridged with a Left Ventricular Assist Device

Acute renal failure (ARF) and chronic kidney disease (CKD) are associated with short- and long-term morbidity and mortality following heart transplantation (HT). We investigated the incidence and risk factors for developing ARF requiring hemodialysis (HD) and CKD following HT specifically in patients with a left ventricular assist device (LVAD). We examined the International Society for Heart and Lung Transplantation (ISHLT) Thoracic Transplant Registry for heart transplant patients between January 2000 and June 2015. We compared patients bridged with durable continuous-flow LVAD to those without LVAD support. Primary outcomes were ARF requiring HD before discharge following HT and CKD (defined as creatinine >2.5 mg/dl, permanent dialysis, or renal transplant) within 3 years. There were 18,738 patients, with 4,535 (24%) bridged with LVAD support. Left ventricular assist device patients had higher incidence of ARF requiring HD and CKD at 1 year, but no significant difference in CKD at 3 years compared to non-LVAD patients. Among LVAD patients, body mass index (BMI) (odds ratio [OR] = 1.79, p < 0.001), baseline estimated glomerular filtration rate (eGFR) (OR = 0.43, p < 0.001), and ischemic time (OR = 1.28, p = 0.014) were significantly associated with ARF requiring HD. Similarly, BMI (hazard ratio [HR] = 1.49, p < 0.001), baseline eGFR (HR = 0.41, p < 0.001), pre-HT diabetes mellitus (DM) (HR = 1.37, p = 0.011), and post-HT dialysis before discharge (HR = 3.93, p < 0.001) were significantly associated with CKD. Left ventricular assist device patients have a higher incidence of ARF requiring HD and CKD at 1 year after HT compared with non-LVAD patients, but incidence of CKD is similar by 3 years. Baseline renal function, BMI, ischemic time, and DM can help identify LVAD patients at risk of ARF requiring HD or CKD following HT.

Outcome and safety of a surveillance biopsy guided personalized immunosuppression program after liver transplantation

Graft survival beyond year 1 has not changed after orthotopic liver transplantation (OLT) over the last decades. Likewise, OLT causes comorbidities such as infection, renal impairment and cancer. We evaluated our single-center real-world individualized immunosuppression program after OLT, based on 211 baseline surveillance biopsies (svLbx) without any procedural complications. Patients were classified as low, intermediate and high rejection risk based on graft injury in svLbx and anti-HLA donor-specific antibodies. While 32% of patients had minimal histological inflammation, 57% showed histological inflammation and 23% advanced fibrosis (>F2), which was not predicted by lab parameters. IS was modified in 79% of patients after svLbx. After immunosuppression reduction in 69 patients, only 5 patients showed ALT elevations and three of these patients had a biopsy-proven acute rejection, two of them related to lethal comorbidities. The rate of liver enzyme elevation including rejection was not significantly increased compared to a svLbx control cohort prior to the initiation of our structured program. Immunosuppression reduction led to significantly better kidney function compared to this control cohort. In conclusion, a biopsy guided personalized immunosuppression protocol after OLT can identify patients requiring lower immunosuppression or patients with graft injury in which IS should not be further reduced.

Changing the terminology from kidney replacement therapy to kidney support therapy

Kidney replacement therapy (KRT) is a common supportive treatment for renal dysfunction, especially acute kidney injury. However, critically ill or immunosuppressed patients with renal dysfunction often have dysfunction in other organs as well. To improve patient outcomes, clinicians began to initiate kidney replacement therapy in situations where nonrenal conditions may lead to acute kidney injury, such as septic shock, hematopoietic stem cell transplantation, veno-occlusive renal disease, cardiopulmonary bypass, chemotherapy, tumor lysis syndrome, hyperammonemia, and various others. In this review, we discuss the use of various modes of kidney replacement therapy in treating renal and nonrenal complications to illustrate why kidney support therapy is a more appropriate terminology than kidney replacement therapy.

Acute Kidney Injury after Lung Transplantation: A Systematic Review and Meta-Analysis

Background: Lung transplantation has been increasingly performed worldwide and is considered an effective therapy for patients with various causes of end-stage lung diseases. We performed a systematic review to assess the incidence and impact of acute kidney injury (AKI) and severe AKI requiring renal replacement therapy (RRT) in patients after lung transplantation. Methods: A literature search was conducted utilizing Ovid MEDLINE, EMBASE, and Cochrane Database from inception through June 2019. We included studies that evaluated the incidence of AKI, severe AKI requiring RRT, and mortality risk of AKI among patients after lung transplantation. Pooled incidence and odds ratios (ORs) with 95% confidence interval (CI) were obtained using random-effects meta-analysis. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42019134095). Results: A total of 26 cohort studies with a total of 40,592 patients after lung transplantation were enrolled. Overall, the pooled estimated incidence rates of AKI (by standard AKI definitions) and severe AKI requiring RRT following lung transplantation were 52.5% (95% CI: 45.8–59.1%) and 9.3% (95% CI: 7.6–11.4%). Meta-regression analysis demonstrated that the year of study did not significantly affect the incidence of AKI (p = 0.22) and severe AKI requiring RRT (p = 0.68). The pooled ORs of in-hospital mortality in patients after lung transplantation with AKI and severe AKI requiring RRT were 2.75 (95% CI, 1.18–6.41) and 10.89 (95% CI, 5.03–23.58). At five years, the pooled ORs of mortality among patients after lung transplantation with AKI and severe AKI requiring RRT were 1.47 (95% CI, 1.11–1.94) and 4.79 (95% CI, 3.58–6.40), respectively. Conclusion: The overall estimated incidence rates of AKI and severe AKI requiring RRT in patients after lung transplantation are 52.5% and 9.3%, respectively. Despite advances in therapy, the incidence of AKI in patients after lung transplantation does not seem to have decreased. In addition, AKI after lung transplantation is significantly associated with reduced short-term and long-term survival.

Incidence and Impact of Acute Kidney Injury after Liver Transplantation: A Meta-Analysis

Background: The study’s aim was to summarize the incidence and impacts of post-liver transplant (LTx) acute kidney injury (AKI) on outcomes after LTx. Methods: A literature search was performed using the MEDLINE, EMBASE and Cochrane Databases from inception until December 2018 to identify studies assessing the incidence of AKI (using a standard AKI definition) in adult patients undergoing LTx. Effect estimates from the individual studies were derived and consolidated utilizing random-effect, the generic inverse variance approach of DerSimonian and Laird. The protocol for this systematic review is registered with PROSPERO (no. CRD42018100664). Results: Thirty-eight cohort studies, with a total of 13,422 LTx patients, were enrolled. Overall, the pooled estimated incidence rates of post-LTx AKI and severe AKI requiring renal replacement therapy (RRT) were 40.7% (95% CI: 35.4%–46.2%) and 7.7% (95% CI: 5.1%–11.4%), respectively. Meta-regression showed that the year of study did not significantly affect the incidence of post-LTx AKI (p = 0.81). The pooled estimated in-hospital or 30-day mortality, and 1-year mortality rates of patients with post-LTx AKI were 16.5% (95% CI: 10.8%–24.3%) and 31.1% (95% CI: 22.4%–41.5%), respectively. Post-LTx AKI and severe AKI requiring RRT were associated with significantly higher mortality with pooled ORs of 2.96 (95% CI: 2.32–3.77) and 8.15 (95%CI: 4.52–14.69), respectively. Compared to those without post-LTx AKI, recipients with post-LTx AKI had significantly increased risk of liver graft failure and chronic kidney disease with pooled ORs of 3.76 (95% CI: 1.56–9.03) and 2.35 (95% CI: 1.53–3.61), respectively. Conclusion: The overall estimated incidence rates of post-LTx AKI and severe AKI requiring RRT are 40.8% and 7.0%, respectively. There are significant associations of post-LTx AKI with increased mortality and graft failure after transplantation. Furthermore, the incidence of post-LTx AKI has remained stable over the ten years of the study.

Incidence of acute kidney disease after receiving hematopoietic stem cell transplantation: a single-center retrospective study

Background

Previous reports have shown that acute kidney injury (AKI) is common after hematopoietic stem cell transplantation (HSCT), which is a crucial treatment for patients with hematological disorders. AKI could increase mortality and induce adverse effects including the development of chronic kidney disease. The incidence of AKI in association with HSCT reportedly varies significantly because several definitions of AKI have been adopted. Acute kidney disease (AKD) is a new concept that can clinically define both AKI and persistent decreases in glomerular filtration rate (GFR) state. We conducted a retrospective cohort study to determine the incidence of AKD after HSCT.

Methods

This study included 108 patients aged between 16 and 70 years undergoing HSCT. In this study, AKD included clinical condition of AKI or subacute decreases in GFR. AKI was defined according to the Kidney Disease: Improving Global Outcomes guidelines based on serum creatinine. However, urine output data were not included to define AKI because the database lacked some of these data. Comparisons were made between groups using the Mann–Whitney U test.

Results

Acute kidney disease occurred in 17 patients (15.7%). There were significant differences between the AKD and non-AKD with respect to ABO-incompatible HSCT (p = 0.001) and incidence of acute graft versus host disease (GVHD) after HSCT (p < 0.001). The 100-day overall survival of patients with AKD and without AKD after HSCT was 70.6% and 79.8%, respectively (p = 0.409).

Discussion

ABO-incompatible HSCT and acute GVHD after HSCT were risk factors for the incidence of AKD. However, we could not find a significant association between AKD after HSCT and mortality.

Acute Kidney Injury in Hematopoietic Stem Cell Transplantation: A Review

Hematopoietic stem cell transplantation (HSCT) is a highly effective treatment strategy for lymphoproliferative disorders and bone marrow failure states including aplastic anemia and thalassemia. However, its use has been limited by the increased treatment related complications, including acute kidney injury (AKI) with an incidence ranging from 20% to 73%. AKI after HSCT has been associated with an increased risk of mortality. The incidence of AKI reported in recipients of myeloablative allogeneic transplant is considerably higher in comparison to other subclasses mainly due to use of cyclosporine and development of graft-versus-host disease (GVHD) in allogeneic groups. Acute GVHD is by itself a major independent risk factor for the development of AKI in HSCT recipients. The other major risk factors are sepsis, nephrotoxic medications (amphotericin B, acyclovir, aminoglycosides, and cyclosporine), hepatic sinusoidal obstruction syndrome (SOS), thrombotic microangiopathy (TMA), marrow infusion toxicity, and tumor lysis syndrome. The mainstay of management of AKI in these patients is avoidance of risk factors contributing to AKI, including use of reduced intensity-conditioning regimen, close monitoring of nephrotoxic medications, and use of alternative antifungals for prophylaxis against infection. Also, early identification and effective management of sepsis, tumor lysis syndrome, marrow infusion toxicity, and hepatic SOS help in reducing the incidence of AKI in HSCT recipients.

Acute Kidney Disease After Liver and Heart Transplantation

After transplantation of nonrenal solid organs, an acute decline in kidney function develops in the majority of patients. In addition, a significant number of nonrenal solid organ transplant recipients develop chronic kidney disease, and some develop end-stage renal disease, requiring renal replacement therapy. The incidence varies depending on the transplanted organ. Acute kidney injury after nonrenal solid organ transplantation is associated with prolonged length of stay, cost, increased risk of death, de novo chronic kidney disease, and end-stage renal disease. This overview focuses on the risk factors for posttransplant acute kidney injury after liver and heart transplantation, integrating discussion of proteinuria and chronic kidney disease with emphasis on pathogenesis, histopathology, and management including the use of mechanistic target of rapamycin inhibition and costimulatory blockade.

Renal pathology associated with hematopoietic stem cell transplantation

The kidney is subject to a large variety of injurious factors before, during, and after hematopoietic stem cell transplantation (HCT), leading to a high incidence of acute kidney injury in the peritransplant period. Chronic kidney disease is estimated to impact 15% to 20% of HCT recipients. Although renal biopsies may be deferred in the setting of thrombotic microangiopathy, acute self-limited impairment, or slowly progressive functional decline, in many patients renal biopsy yields important diagnostic insight to guide treatment. Light microscopic, immunofluorescence, and ultrastructural analysis often reveals a number of concurrent abnormalities in glomeruli, tubules, interstitium, and vessels. Meta-analysis of the literature reveals that membranous nephropathy is the most commonly reported glomerular lesion in the setting of HCT, followed by minimal change disease. Autopsy and biopsy studies show that clinical criteria lack sensitivity and specificity for renal acute and chronic thrombotic microangiopathy. Viral infection and other causes of interstitial nephritis and tubular injury are important findings in HCT renal biopsies, which in many instances may not be clinically suspected. Given the complexity and variability of HCT protocols, clinicopathologic correlation is needed.

Solid organ transplantation following end-organ failure in recipients of hematopoietic stem cell transplantation in children

Hematopoietic stem cell transplantation (HSCT) is an accepted treatment modality for various malignant and non-malignant disorders of the lympho-hematopoietic system. Patient survival rate has increased significantly with the use of this procedure. However, with the increase in disease-free patient survival rates, complications including various organ toxicities are also common. Kidney, liver, lung, heart, and skin are among those solid organs that are commonly affected and frequently lead to organ dysfunction and eventually end-organ disease. Conservative measures may or may not be successful in managing the organ failure in these patients. Solid organ transplantation has been shown to be promising in those patients who fail conservative management. This review will summarize the causes of solid organ (kidney, liver, and lung) dysfunction and the available data on transplantation of these solid organs in post-HSCT recipients.

Sirolimus Immunoprophylaxis and Renal Histological Changes in Long-Term Cardiac Transplant Recipients

Background: The effects of sirolimus (SIR), as a substitution for calcineurin inhibitor (CNI) immunoprophylaxis, on renal function in very-long-term cardiac transplant recipients have been a matter of controversy. Objective: To assess the impacts of SIR as a substitution for CNI on renal function up to 24 months in long-term cardiac recipients as well as the renal histological changes in patients with suspected CNI-induced nephrotoxicity. Methods: A total of 23 cardiac transplant recipients aged 57.7 ± 11.2 years, 91 months post–cardiac transplantation were recruited; 15 patients were randomized to CNI-free immune suppression with SIR, and 8 patients were allocated to continue their CNI regimens. Serum creatinine and calculated serum creatinine clearance were measured at prespecified time points up to 24 months. Renal structure and function were assessed by renal biopsies, renal ultrasound, and magnetic resonance imaging at baseline. Results: There were no significant changes in creatinine clearance during the course of the study in patients treated with SIR. However, SIR-treated patients exhibited a significant decrease in 24-hours and nighttime systolic and diastolic blood pressures. Typical findings of significant hypertensive renal disease were detected in 9 of the 11 (82%) patients. Features of chronic CNI toxicity were detected in 6 (55%) patients. Conclusions: There is a very high rate of hypertensive renal disease concomitantly with some degree of CNI toxicity in long-term cardiac transplant recipients with renal dysfunction. This very high rate of hypertension-related disease may limit the impact of SIR on improving renal function long term following cardiac transplantation.

Natriuretic peptides in the management of solid organ transplantation associated acute kidney injury: a systematic review and meta-analysis

Randomized controlled trials involving natriuretic peptide administration in solid organ transplantation setting have shown inconsistent effects for renal endpoints. We conducted a systematic review and meta-analysis of these trials to ascertain the role of natriuretic peptides in the management of solid organ transplantation associated acute kidney injury (AKI). MEDLINE, EMBASE, and Google scholar were searched independently by two authors for randomized trials evaluating renal effects of natriuretic peptides in solid organ transplantation settings. Two reviewers independently assessed the studies for eligibility and extracted the relevant data. The pooled estimate showed that natriuretic peptide administration is associated with a reduction in AKI requiring dialysis (odds ratio = 0.50 [0.26–0.97]), a statistically nonsignificant trend toward improvement in posttransplant creatinine clearance (weighted mean difference = 5.5 mL/min, [−1.3 to 12.2 mL/min]), and reduction in renal replacement requirement duration (weighted mean difference −44.0 hours, [−60.5 to −27.5 hours]). There were no mortality events and no adverse events related to natriuretic peptides. In conclusion, administration of natriuretic peptides in solid organ transplantation may be associated with significant improvements in renal outcomes. These observations need to be confirmed in an adequately powered, prospective multicenter study.