Reversal of oliguric tacrolimus nephrotoxicity in children

Evaluation of Aminophylline for the Treatment of Acute Kidney Injury in Pediatric Hematology/Oncology Patients

OBJECTIVE

The purpose of this study was to compare acute kidney injury (AKI)-related outcomes of patients who received aminophylline in addition to standard of care with matched historical controls who received standard of care alone.

METHODS

This was a single center, retrospective, historical control cohort study that included patients treated for AKI. Patients who received aminophylline from January 2017 to June 2018 were matched for age, sex, primary diagnosis, and hematopoietic cell transplant history in a 1:2 ratio to historical controls treated for AKI from July 2015 to September 2016. The primary outcome was improvement in AKI stage at 5 and 10 days from treatment initiation.

RESULTS

Twenty-seven patients who received aminophylline were matched to 54 historical controls. Fifty-eight patients (72%) had recently undergone hematopoietic cell transplant. At day 5, improvement in AKI stage was observed in 56% of patients in each group (p = 1.0); at day 10, improvement in AKI stage was observed in 75% of patients in the aminophylline group vs 70% of historical controls (p = 0.76). By day 10, serum creatinine levels had returned to baseline in 21% of patients in the aminophylline group and 34% of patients in the control group (p = 0.37).

CONCLUSIONS

Findings of this study demonstrated no difference in the rate of AKI resolution or in the proportion of patients with resolved AKI when aminophylline was added to standard of care for the treatment of AKI in this pediatric hematology/oncology population.

Nephrotoxins and nephrotoxic acute kidney injury

Although the concept of nephrotoxicity has been recognized for more than 80 years, interest in nephrotoxins has intensified dramatically over the past two decades. Much of this attention has rightfully been focused on pharmaceutical agents and iatrogenic harm; however, it is important for providers to recognize that nephrotoxins can be found in naturally occurring substances as well. Although nephrotoxins exist in a myriad of forms, the means by which they induce injury can be organized into a few categories. For most of these agents, regardless of the mechanism, the final common pathway is acute kidney injury (AKI). Unfortunately, therapeutic options are limited and no treatments currently exist to reverse nephrotoxic AKI once it occurs. As a result, current strategies focus on increased awareness, nephrotoxin avoidance, early injury detection, and mitigation of disease severity. The goal of this review is to summarize our current understanding of nephrotoxic mechanisms and the epidemiology of nephrotoxic AKI. Additionally, avoidance and preventative strategies are discussed, screening approaches are suggested, and chronic monitoring recommendations are made.

Peri-transplant aminophylline in pediatric kidney transplant recipients of donation after brain death: a double-blinded placebo-controlled randomized clinical trial

BACKGROUND

During kidney transplantation, the transplanted kidney undergoes ischemia reperfusion injury, with adenosine being a major mediator. This study aimed to assess whether aminophylline, an adenosine receptor antagonist, improves early graft function and reduces incidence of delayed graft function (DGF) and slow graft function (SGF).

METHODS

Single center, double-blinded, placebo-controlled randomized clinical trial. Pediatric patients admitted for renal transplantation from donation after brain death donors were randomized into a treatment arm receiving aminophylline and a placebo arm receiving normal saline infusions. Primary outcome was estimated glomerular filtration rate (eGFR) at 5 days post-transplant. Secondary outcomes were rates of DGF/SGF and urinary neutrophil gelatinase-associated lipocalin (NGAL) levels.

RESULTS

Twenty-three patients were randomized to aminophylline and 27 to placebo. There was no difference in day 5 eGFR, rate of DGF/SGF, or urine NGAL/Creatinine level between aminophylline vs. placebo arm (eGFR 67.39 ± 38.9 ml/min/1.73m² vs. 80.48 ± 52.1 ml/min/1.73m²p = 0.32; DGF/SGF 5/23 (21.7%) vs. 3/27 (11.1%) p = 0.31; urine NGAL/creatinine 300.5 ng/mg IQR 105.5-1464.5 ng/mg vs. 425.4 ng/mg IQR 140.3-1126.2 ng/mg, p = 0.95; respectively). At 12 months, there was 100% patient survival and 98% graft survival. eGFR at 12 months was similar between the two arms.

CONCLUSIONS

There was no benefit in peri-transplant aminophylline administration. Our results are limited by small sample size, since sample calculations were based on primary outcome of day 5 eGFR and low rate of DGF/SGF, which may have precluded us from demonstrating efficacy. Further clinical studies are necessary to determine any benefit of aminophylline in kidney transplant recipients, particularly from high-risk donors.

Xanthine Derivatives for Kidney Protection in the Critically Ill Pediatric Population: A Systematic Review

Different types of diuretics have been used to minimize fluid overload after resuscitation. This meta-analysis determined the effects of xanthine derivatives on creatinine, creatinine clearance, and urine output. Studies included data from pediatric patients, whoused theophylline or aminophylline, and included pre- and postxanthine data for at least one of the outcomes of interest. A total of 13 studies with 198 patients were included in the pooled analyses. The study recorded data prior, and a mean of 36 hours after xanthine administration. This meta-analysis demonstrates that xanthine derivatives in critically ill children, using a dose of approximately5 mg/kg, lead to a statistically significant increase in creatinine clearance and urine output without significantly altering serum creatinine. Xanthine derivatives may be beneficial for fluid management in critically ill children. Further studies are warranted assessing the association with additional clinical outcomes.

Electronic Health Record-Enabled Big-Data Approaches to Nephrotoxin-Associated Acute Kidney Injury Risk Prediction

Nephrotoxin-associated acute kidney injury (NTx-AKI) has become one of the most common causes of AKI among hospitalized adults and children; across acute and intensive care populations, exposure to nephrotoxins accounts for 15-25% of AKI cases. Although some interventions have shown promise in observational studies, no treatments currently exist for NTx-AKI once it occurs. Thus, nearly all effective strategies are aimed at prevention. The primary obstacle to prevention is risk prediction and the determination of which patients are more likely to develop NTx-AKI when exposed to medications with nephrotoxic potential. Historically, traditional statistical modeling has been applied to previously recognized clinical risk factors to identify predictors of NTx-AKI. However, increased electronic health record adoption and the evolution of "big-data" approaches to predictive analytics may offer a unique opportunity to prevent NTx-AKI events. This article describes prior and current approaches to NTx-AKI prediction and offers three novel use cases for electronic health record-enabled NTx-AKI forecasting and risk profiling.

Aminophylline Effect on Renal Ischemia-Reperfusion Injury in Mice

BACKGROUND

Aminophylline increases the intracellular concentration of cAMP and exerts an anti-inflammatory effect. The aim of this study was to investigate the effect of aminophylline on renal ischemia-reperfusion (I/R) injury in mice.

METHODS

Thirty C57BL/6 mice were divided into 3 groups. In the sham group (group S, n = 10), only right nephrectomy was performed. In the control group (group C, n = 10), after right nephrectomy, the mice were subjected to 30 minutes of left renal ischemia. In the aminophylline group (group A, n = 10), an intraperitoneal injection of aminophylline (5 mg/kg) was performed before renal ischemia. Twenty-four hours after reperfusion, the mice were euthanized, and plasma and kidney samples were obtained to analyze the serum creatinine, renal histology, and expression levels of nuclear factor-kappa B (NF-kB) and pro-inflammatory cytokines.

RESULTS

The serum creatinine concentration in group C was markedly elevated at 24 hours after reperfusion. Aminophylline treatment significantly reduced serum creatinine, compared with group C. Aminophylline also reduced the histological evidence of renal damage. The expression levels of NF-kB, tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-2 (MIP-2), and intercellular adhesion molecule-1 (ICAM-1) mRNA were significantly increased in group C (P < .001). Group A showed lower expression of NF-kB, TNF-α, MCP-1, MIP-2, and ICAM-1 mRNA than group C (P < .01).

CONCLUSIONS

Aminophylline treatment improved the renal function and indexes of renal inflammation, which suggests that it provided reno-protection against renal I/R injury.

A Double-Blinded, Randomized, Placebo-Controlled Clinical Trial of Aminophylline to Prevent Acute Kidney Injury in Children Following Congenital Heart Surgery With Cardiopulmonary Bypass

OBJECTIVES

Acute kidney injury occurs commonly in children following congenital cardiac surgery with cardiopulmonary bypass and has been associated with increased morbidity and mortality. Aminophylline, a methylxanthine nonselective adenosine receptor antagonist, has been effective in the management of acute kidney injury in certain populations. This study sought to determine whether postoperative administration of aminophylline attenuates acute kidney injury in children undergoing congenital cardiac surgery with cardiopulmonary bypass.

DESIGN

Single-center, double-blinded, placebo-controlled, randomized clinical trial.

SETTING

Tertiary center, pediatric cardiovascular ICU.

PATIENTS

A total of 144 children after congenital heart surgery with cardiopulmonary bypass.

INTERVENTIONS

Seventy-two patients were randomized to receive aminophylline and 72 patients received placebo. Study drug was administered every 6 hours for 72 hours.

MEASUREMENTS AND MAIN RESULTS

The primary outcome variable was the development of any acute kidney injury, defined by the serum creatinine criteria of the Kidney Diseases: Improving Global Outcomes. Secondary outcomes included the development of severe acute kidney injury, time between cardiovascular ICU admission and first successful extubation, percent fluid overload, total fluid balance, urine output, bioelectrical impedance, and serum neutrophil gelatinase-associated lipocalin. The unadjusted rate and severity of acute kidney injury were not different between groups; 43 of 72 (60%) of the treatment group and 36 of 72 (50%) of the placebo group developed acute kidney injury (p = 0.32). Stage 2/3 acute kidney injury occurred in 23 of 72 (32%) of the treatment group and 15 of 72 (21%) of the placebo group (p = 0.18). Secondary outcome measures also demonstrated no significant difference between treatment and placebo groups. Aminophylline administration was safe; no deaths occurred in either group, and rates of adverse events were similar (14% in the treatment group vs 18% in the placebo group; p = 0.30).

CONCLUSIONS

In this placebo-controlled randomized clinical trial, we found no effect of aminophylline to prevent acute kidney injury in children recovering from cardiac surgery performed with cardiopulmonary bypass. Future study of preoperative aminophylline administration to prevent acute kidney injury may be warranted.

Initial experience using aminophylline to improve renal dysfunction in the pediatric cardiovascular ICU

OBJECTIVE

To determine if aminophylline administration is associated with improved creatinine clearance and greater urine output in children with acute kidney injury in the cardiovascular ICU.

DESIGN

Single-center retrospective cohort study.

SETTING

Pediatric cardiovascular ICU, university-affiliated children's hospital.

PATIENTS

Children with congenital or acquired heart disease in the cardiovascular ICU who received aminophylline to treat oliguric acute kidney injury and fluid overload.

INTERVENTIONS

Patients received aminophylline after consultation with a pediatric nephrologist. Data were collected retrospectively over 7 days to assess if aminophylline was associated with improvement in creatinine clearance, urine output, and fluid overload.

MEASUREMENTS AND MAIN RESULTS

Thirty-one patients received 52 aminophylline courses. Over the 7-day study period, serum creatinine decreased from a mean of 1.13 ± 0.91 to 0.87 ± 0.83 mg/dL (-0.05 mg/dL/d, p < 0.001). A concomitant increase was seen in estimated glomerular filtration rate from a mean of 50.0 ± 30.0 to 70.6 ± 58.1 mL/min/1.73 m (+3.66 mL/min/1.73 m/d, p < 0.001). Average daily urine output increased by 0.22 mL/kg/hr (p < 0.001), and fluid overload decreased on average by 0.42% per day in the 7-day study period (p = 0.005). Although mean furosemide dose increased slightly (0.12 mg/kg/d, p = 0.01), hydrochlorothiazide dosing did not significantly change over the study period. There were no complications related to aminophylline administration.

CONCLUSIONS

Our study suggests that aminophylline therapy may be associated with significantly improved renal excretory function and may augment urine output in children who experience oliguric acute kidney injury in the cardiovascular ICU. Additionally, we did not identify any aminophylline-related side effects in this high-risk cardiac population. Future prospective studies are necessary to confirm the safety profile and to ensure that the beneficial effects are independent of other clinical interventions.

A prospective assessment of the effect of aminophylline therapy on urine output and inflammation in critically ill children

BACKGROUND

Aminophylline, an established bronchodilator, is also purported to be an effective diuretic and anti-inflammatory agent. However, the data to support these contentions are scant. We conducted a prospective, open-label, single arm, single center study to assess the hypothesis that aminophylline increases urine output and decreases inflammation in critically ill children.

METHODS

Children less than 18 years of age admitted to the pediatric intensive care unit who were prescribed aminophylline over a 24-h period were eligible for study. The use and dosing of aminophylline was independent of the study and was at the discretion of the clinical team. Data analyzed consisted of demographics, diagnoses, medications, and markers of pulmonary function, renal function, and inflammation. Data were collected at baseline and at 24-h after aminophylline initiation with primary outcomes of change in urine output and inflammatory cytokine concentrations.

RESULTS

Thirty-five patients were studied. Urine output increased significantly with aminophylline use [median increase 0.5 mL/kg/h (IQR: -0.3, 1.3), p = 0.05] while blood urea nitrogen and creatinine concentrations remained unchanged. Among patients with elevated C-reactive protein concentrations, levels of both interleukin-6 (IL-6) and IL-10 decreased at 24 h of aminophylline therapy. There were no significant differences in pulmonary compliance or resistance among patients invasively ventilated at both time points. Side effects of aminophylline were detected in 7 of 35 patients.

CONCLUSION

Although no definitive conclusions can be drawn from this study, aminophylline may be a useful diuretic and effective anti-inflammatory medication in critically ill children. Given the incidence of side effects, the small sample size and the uncontrolled study design, further study is needed to inform the appropriate use of aminophylline in these children.

Nonsurgical care of intestinal and multivisceral transplant recipients: a review for the intensivist

Intestinal and multivisceral transplantation has evolved from an experimental procedure to the treatment of choice for patients with irreversible intestinal failure and serious complications related to long-term parenteral nutrition. Increased numbers of transplant recipients and improved survival rates have led to an increased prevalence of this patient population in intensive care units. Management of intestinal and multivisceral transplant recipients is uniquely challenging because of complications arising from the high incidence of transplant rejection and its treatment. Long-term comorbidities, such as diabetes, hypertension, chronic kidney failure, and neurological sequelae, also develop in this patient population as survival improves. This article is intended for intensivists who provide care to critically ill recipients of intestinal and multivisceral transplants. As perioperative care of intestinal/multivisceral transplant recipients has been described elsewhere, this review focuses on common nonsurgical complications with which one should be familiar in order to provide optimal care. The article is both a review of the current literature on multivisceral and isolated intestinal transplantation as well as a reflection of our own experience at the University of Miami.

Additive diuretic response of concurrent aminophylline and furosemide in children: a case series and a brief literature review

Aminophylline exerts a renovascular effect, acting by adenosine receptor blockade or type IV phosphodiesterase inhibition. Clinically, these drugs have been used with furosemide to induce diuresis in adults and neonates. However, reports on use of aminophylline in diuretic-dependent children are limited to a few studies. We report a case series of four critically ill children unresponsive to furosemide continuous infusion who were subsequently given aminophylline as an adjunct diuretic in the treatment of fluid overload. No side effects were evident. Administration of aminophylline at low doses (3 mg/kg) successfully promoted increased urine output over the 6-h study period in all four children.

Methylxanthines and the kidney

This chapter describes the effects of the natural methylxanthines caffeine and theophylline on kidney function. Theophylline in particular was used traditionally to increase urine out put until more potent diuretics became available in the middle of the last century. The mildly diuretic actions of both methylxanthines are mainly the result of inhibition of tubular fluid reabsorption along the renal proximal tubule. Based upon the use of specific adenosine receptor antagonists and the observation of a complete loss of diuresis in mice with targeted deletion of the A1AR gene, transport inhibition by methylxanthines is mediated mainly by antagonism of adenosine A1 receptors (A1AR) in the proximal tubule. Methylxanthines are weak renal vasodilators, and they act as competitive antagonists against adenosine-induced preglomerular vasoconstriction. Caffeine and theophylline stimulate the secretion of renin by inhibition of adenosine receptors and removal of the general inhibitory brake function of endogenous adenosine. Since enhanced intrarenal adenosine levels lead to reduced glomerular filtration rate in several pathological conditions theophylline has been tested for its therapeutic potential in the renal impairment following administration of nephrotoxic substances such as radiocontrast media, cisplatin, calcineurin inhibitors or following ischemia-reperfusion injury. In experimental animals functional improvements have been observed in all of these conditions, but available clinical data in humans are insufficient to affirm a definite therapeutic efficacy of methylxanthines in the prevention of nephrotoxic or postischemic renal injury.

Preclinical evaluation of tacrolimus colloidal dispersion for inhalation

Substantial improvements in transplant therapy have been made in the past four decades resulting in the acceptance of organ transplantation as a viable treatment for late-stage disease and organ failure. More recently, lung transplantation has gained acceptance; however, high incidence of chronic rejection and opportunistic infections has limited success rates in comparison with other transplant procedures. To achieve more targeted therapy, pulmonary administration of nebulized tacrolimus (TAC) colloidal dispersion once daily for 28 consecutive days in Sprague Dawley (SD) rats has been investigated for safety and systemic elimination. A liquid dispersion of colloidal TAC and lactose (1:1 ratio by weight) was aerosolized using a vibrating mesh nebulizer and administered via a nose-only dosing chamber. Blood chemistry and histological comparisons to saline-dosed animals showed no clinically significant differences in liver and kidney function or lung tissue damage. Maximum blood and lung concentrations sampled 1h after the final dose showed TAC concentrations of 10.1 ± 1.4 ng/mL and 1758.7 ± 80.0 ng/g, respectively. Twenty-four hours after the final dose, systemic TAC concentrations measured 1.0 ± 0.5 ng/mL, which is well below clinically accepted trough concentrations (5-15 ng/mL) for maintenance therapy, and therefore, would not be expected to induce toxic side effects. The propensity for pulmonary retention seen when compared to single dose lung levels may be due to macrophage uptake and the lipophilic nature of TAC. Additionally, three month stability testing of TAC powder for reconstitution showed no changes in amorphous nature or drug potency when stored at ambient conditions. TAC colloidal dispersion proved to be non-toxic when administered by pulmonary inhalation to SD rats over 28 days while providing therapeutic concentrations locally. This delivery strategy may prove safe and effective for the prevention of lung allograft rejection in lung transplant recipients.

Calcium channel blockers for preventing acute tubular necrosis in kidney transplant recipients

BACKGROUND

The incidence of delayed graft function in cadaveric grafts has increased over the last few years due in part to the large demand for cadaveric kidneys necessitating the use of kidneys from marginal donors. Calcium channel blockers have the potential to reduce the incidence of post-transplant acute tubular necrosis (ATN) if given in the peri-operative period. However, there is controversy surrounding their use in this situation with no consensus as to their efficacy.

OBJECTIVES

To evaluate the benefits and harms of using calcium channel blockers in the peri-transplant period in patients at risk of ATN following cadaveric kidney transplantation.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library) MEDLINE (from 1966) and EMBASE (from 1980). The Trials Search Coordinator was contacted to develop the search strategy. Date of last search: January 2007

SELECTION CRITERIA

Randomised controlled trials comparing calcium channel blockers given in the peri-transplant period with controls were included. Quasi-randomised trials were excluded.

DATA COLLECTION AND ANALYSIS

Data was extracted and quality assessed independently by two reviewers, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and measurements on continuous scales are reported as mean differences (WMD) with 95% confidence intervals (CI).

MAIN RESULTS

Thirteen trials (724 participants) were suitable for inclusion. Treatment with calcium channel blockers in the peri-transplant period was associated with a significant decrease in the incidence of post-transplant ATN (RR 0.62, 95% CI 0.46 to 0.85) and delayed graft function (RR 0.55, 95% CI 0.42 to 0.73). There was no difference between control and treatment groups in graft loss, mortality, requirement for haemodialysis. There was insufficient information to comment on adverse events.

AUTHORS' CONCLUSIONS

These results suggest that calcium channel blockers given in the peri-operative period may reduce the incidence of ATN post-transplantation. The result should be treated with caution due to the heterogeneity of the trials which made comparison of studies and pooling of data difficult.

Adenosine receptor antagonism in acute tacrolimus toxicity

BACKGROUND

Calcineurin inhibitors induce renal vasoconstriction and oliguria during acute toxicity. We previously demonstrated that the non-specific adenosine receptor antagonist theophylline improved glomerular filtration rate (GFR) and renal blood flow in the setting of acute tacrolimus (TAC) toxicity. This study was undertaken to determine which of the known adenosine receptor subtypes is responsible for the observed effect of theophylline.

METHODS

The GFR was measured by clearance of 51Cr-EDTA in anaesthetized, instrumented Sprague-Dawley rats at three time points: at baseline, 60 min after intravenous administration of TAC (0.05 mg/kg) or vehicle (V) and at 100 min after TAC or V. Either DMSO (n = 5) or one of the three available specific adenosine receptor subtype antagonists 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 2 mg/kg, n = 5), a selective A1 receptor antagonist, 8-(3-chlorostyryl) caffeine (CSC, 2 mg/kg, n = 4), a selective A2a receptor antagonist and 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-dihydropyridine-3,5 dicarboxylate (MRS1191, 1 mg/kg, n = 5), a selective A3 receptor antagonist, was administered intra-peritoneally prior to the final GFR measurement. Repeated measures analysis of variance was used to detect differences between groups (P < 0.05).

RESULTS

Measured GFR declined by 30% from baseline 60 min after TAC. In DMSO treated animals, GFR decreased 51% from baseline at 100 min after TAC, but increased 45% from baseline at 100 min after TAC + MRS1191.

CONCLUSIONS

Only administration of the A3 adenosine antagonist increased GFR following TAC, suggesting that this receptor mediates the effect of theophylline on GFR.