Associations between Intensity of RRT, Inflammatory Mediators, and Outcomes.

BACKGROUND AND OBJECTIVES: Critically ill patients requiring RRT have higher circulating plasma concentrations of inflammatory and apoptosis markers that are associated with subsequent RRT dependence and death. Whether intensive dosing of RRT is associated with changes in specific mediators is unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A multicenter, prospective, cohort study of 817 critically ill patients receiving RRT ancillary to the Veterans Affairs/National Institutes of Health Acute Renal Failure Trial Network study was conducted between November 2003 and July 2007. Plasma inflammatory (IL-6, IL-8, IL-10, IL-18, and macrophage migration inhibitory factor) and apoptosis (TNF receptor-I [TNFR-I], TNFR-II, and death receptor-5) biomarkers on days 1 and 8 were examined after initiation of intensive RRT. Whether intensive RRT, given day 1 biomarkers, is associated with RRT independence and lower mortality at day 60 was also examined. RESULTS: Overall, no differences were found in day 8 biomarker concentrations between intensive and less-intensive RRT groups. When adjusted for day 1 biomarkers and clinical variables, intensive RRT was not associated with renal recovery (adjusted odds ratio [OR], 0.80; 95% confidence interval, 0.56 to 1.14) or mortality (adjusted OR, 1.15; 95% confidence interval, 0.81 to 1.64). Use of intensive RRT, however, was associated with lower day 8 concentrations when day 1 plasma IL-6, macrophage migration inhibitory factor, and TNFR-I concentrations were high (interaction P value for all markers, <0.01). In contrast, day 8 marker concentrations were higher when day 1 levels were low (P<0.01). Elevated biomarker concentrations on day 8 among 476 participants were associated with lower renal recovery (adjusted OR range, 0.19-0.87) and higher mortality (adjusted OR range, 1.26-3.18). CONCLUSIONS: Among critically ill patients receiving RRT, intensive dosing of RRT has variable association with biomarker concentration and no association with renal recovery and mortality. However, elevated concentrations of inflammatory and apoptosis markers on day 8 of RRT were associated with RRT dependence and death.

Protocolized fluid therapy in brain-dead donors: the multicenter randomized MOnIToR trial.

BACKGROUND: Critical shortages of organs for transplantation jeopardize many lives. Observational data suggest that better fluid management for deceased organ donors could increase organ recovery. We conducted the first large multicenter randomized trial in brain-dead donors to determine whether protocolized fluid therapy increases the number of organs transplanted. METHODS: We randomly assigned donors to either protocolized or usual care in eight organ procurement organizations. A "protocol-guided fluid therapy" algorithm targeting the cardiac index, mean arterial pressure and pulse pressure variation was used. Our primary outcome was the number of organs transplanted per donor, and our primary analysis was intention to treat. Secondary analyses included: (1) modified intention to treat where only subjects able to receive the intervention were included and (2) 12-month survival in transplant recipients. The study was stopped early. RESULTS: We enrolled 556 donors: 279 protocolized care and 277 usual care. Groups had similar characteristics at baseline. The study protocol could be implemented in 76 % of subjects randomized to the intervention. There was no significant difference in mean number of organs transplanted per donor: 3.39 organs per donor (95 % CI 3.14-3.63) with protocolized care compared to 3.29 usual care (95 % CI 3.04-3.54; mean difference, 0.1, 95 % CI -0.25 to 0.45; p = 0.56). In modified intention-to-treat analysis the mean number of organs increased (3.52 organs per donor, 95 % CI 3.23-3.8), but not statistically significantly (mean difference, 0.23, 95 % CI -0.15 to 0.61; p = 0.23). Among the 1,430 recipients of organs from study subjects with data available, 56 deaths (7.8 %) occurred in the protocolized care arm and 56 (7.9 %) in the usual care arm in the first year (hazard ratio: 0.97, p = 0.86). CONCLUSIONS: In brain-dead organ donors, protocol-guided fluid therapy compared to usual care may not increase the number of organs transplanted per donor.

Modulation of chemokine gradients by apheresis redirects leukocyte trafficking to different compartments during sepsis, studies in a rat model.

INTRODUCTION: Prior work suggests that leukocyte trafficking is determined by local chemokine gradients between the nidus of infection and the plasma. We recently demonstrated that therapeutic apheresis can alter immune mediator concentrations in the plasma, protect against organ injury, and improve survival. Here we aimed to determine whether the removal of chemokines from the plasma by apheresis in experimental peritonitis changes chemokine gradients and subsequently enhances leukocyte localization into the infected compartment, and away from healthy tissues. METHODS: In total, 76 male adult Sprague-Dawley rats weighing 400 g to 600 g were included in this study. Eighteen hours after inducing sepsis by cecal ligation and puncture, we randomized these rats to apheresis or sham treatment for 4 hours. Cytokines, chemokines, and leukocyte counts from blood, peritoneal cavity, and lung were measured. In a separate experiment, we labeled neutrophils from septic donor animals and injected them into either apheresis or sham-treated animals. All numeric data with normal distributions were compared with one-way analysis of variance, and numeric data not normally distributed were compared with the Mann-Whitney U test. RESULTS: Apheresis significantly removed plasma cytokines and chemokines, increased peritoneal fluid-to-blood chemokine (C-X-C motif ligand 1, ligand 2, and C-C motif ligand 2) ratios, and decreased bronchoalveolar lavage fluid-to-blood chemokine ratios, resulting in enhanced leukocyte recruitment into the peritoneal cavity and improved bacterial clearance, but decreased recruitment into the lung. Apheresis also reduced myeloperoxidase activity and histologic injury in the lung, liver, and kidney. These Labeled donor neutrophils exhibited decreased localization in the lung when infused into apheresis-treated animals. CONCLUSIONS: Our results support the concept of chemokine gradient control of leukocyte trafficking and demonstrate the efficacy of apheresis to target this mechanism and reduce leukocyte infiltration into the lung.

Plasma inflammatory and apoptosis markers are associated with dialysis dependence and death among critically ill patients receiving renal replacement therapy.

BACKGROUND: Survivors of critical illness complicated by acute kidney injury requiring renal replacement therapy (RRT) are at an increased risk of dialysis dependence and death but the mechanisms are unknown. METHODS: In a multicenter, prospective, cohort study of 817 critically ill patients receiving RRT, we examined association between Day 1 plasma inflammatory [interleukin (IL)-1ß, IL-6, IL-8, IL-10 and IL-18; macrophage migration inhibitory factor (MIF) and tumor necrosis factor]; apoptosis [tumor necrosis factor receptor (TNFR)-I and TNFR-II and death receptor (DR)-5]; and growth factor (granulocyte macrophage colony stimulating factor) biomarkers and renal recovery and mortality at Day 60. Renal recovery was defined as alive and RRT independent. RESULTS: Of 817 participants, 36.5% were RRT independent and 50.8% died. After adjusting for differences in demographics, comorbid conditions; premorbid creatinine; nephrotoxins; sepsis; oliguria; mechanical ventilation; RRT dosing; and severity of illness, increased concentrations of plasma IL-8 and IL-18 and TNFR-I were independently associated with slower renal recovery [adjusted hazard ratio (AHR) range for all markers, 0.70-0.87]. Higher concentrations of IL-6, IL-8, IL-10 and IL-18; MIF; TNFR-I and DR-5 were associated with mortality (AHR range, 1.16-1.47). In an analysis of multiple markers simultaneously, increased IL-8 [AHR, 0.80, 95% confidence interval (95% CI) 0.70-0.91, P < 0.001] and TNFR-I (AHR, 0.63, 95% CI 0.50-0.79, P < 0.001) were associated with slower recovery, and increased IL-8 (AHR, 1.26, 95% CI 1.14-1.39, P < 0.001); MIF (AHR, 1.18, 95% CI 1.08-1.28, P < 0.001) and TNFR-I (AHR, 1.26, 95% CI 1.02-1.56, P < 0.03) were associated with mortality. CONCLUSIONS: Elevated plasma concentrations of inflammatory and apoptosis biomarkers are associated with RRT dependence and death. Our data suggest that future interventions should investigate broad-spectrum immune-modulation to improve outcomes.

Urinary biomarkers and renal recovery in critically ill patients with renal support.

BACKGROUND AND OBJECTIVES: Despite significant advances in the epidemiology of acute kidney injury (AKI), prognostication remains a major clinical challenge. Unfortunately, no reliable method to predict renal recovery exists. The discovery of biomarkers to aid in clinical risk prediction for recovery after AKI would represent a significant advance over current practice. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted the Biological Markers of Recovery for the Kidney study as an ancillary to the Acute Renal Failure Trial Network study. Urine samples were collected on days 1, 7, and 14 from 76 patients who developed AKI and received renal replacement therapy (RRT) in the intensive care unit. We explored whether levels of urinary neutrophil gelatinase-associated lipocalin (uNGAL), urinary hepatocyte growth factor (uHGF), urinary cystatin C (uCystatin C), IL-18, neutrophil gelatinase-associated lipocalin/matrix metalloproteinase-9, and urine creatinine could predict subsequent renal recovery. RESULTS: We defined renal recovery as alive and free of dialysis at 60 days from the start of RRT. Patients who recovered had higher uCystatin C on day 1 (7.27 versus 6.60 ng/mg·creatinine) and lower uHGF on days 7 and 14 (2.97 versus 3.48 ng/mg·creatinine; 2.24 versus 3.40 ng/mg·creatinine). For predicting recovery, decreasing uNGAL and uHGF in the first 14 days was associated with greater odds of renal recovery. The most predictive model combined relative changes in biomarkers with clinical variables and resulted in an area under the receiver-operator characteristic curve of 0.94. CONCLUSIONS: We showed that a panel of urine biomarkers can augment clinical risk prediction for recovery after AKI.

Comparison of inflammatory response during on-pump and off-pump coronary artery bypass surgery.

PURPOSE: On-pump coronary artery bypass graft (CABG) surgery has been traditionally associated with a higher magnitude of inflammatory response than off-pump CABG. However with the development of polymer-coated biocompatible extracorporeal circuits, we wanted to see if cardiopulmonary bypass still played an important role in triggering this inflammatory response. METHODS: In this prospective observational study, 33 patients undergoing CABG surgeries (25 on-pump and 8 off-pump patients) were studied. Serial plasma cytokine (TNF IL-6, IL-10) and procalcitonin concentrations were measured at different time-points during and after the surgery. Demographic and baseline clinical data, intra-operative management details and post-operative complications were also collected from the patients' charts. RESULTS: Plasma levels of all 4 mediators increased during surgery and returned towards normal postoperatively. There were no differences between groups for any mediator at any time-point. CONCLUSIONS: We conclude that with the use of recent polymer-coated biocompatible extracorporeal circuits, the inflammatory response triggered by on-pump CABG becomes very similar in magnitude and pattern to that triggered by off-pump CABG. Thus, the surgical procedure contributes to most of the inflammatory response, with the extra-corporeal circuit having minimal to no effect on this response.

Preload responsiveness is associated with increased interleukin-6 and lower organ yield from brain-dead donors.

OBJECTIVE: Brain death induces dramatic changes in hemodynamics. Ischemic injury and inflammation resulting from inadequate resuscitation might influence organ yield for transplantation. Using functional hemodynamic monitoring in brain-dead organ donors, we test the hypothesis that donor preload (fluid) responsiveness is associated with increased inflammatory response and lower organ yield for transplantation. DESIGN: Prospective, observational, pilot study. SETTING: A large intensive care unit of a university hospital in the United States. PATIENTS: Twenty-one brain-dead organ donors between July 2006 and April 2007. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Following declaration of brain death, we collected data on donor demographics, mechanism of brain death, and number of organs procured and transplanted. Functional hemodynamics were monitored using pulse contour analysis technique. Plasma tumor necrosis factor, interleukin-6, and interleukin-10 concentrations were measured at study enrollment, after 4 hrs, and immediately before organ procurement for transplantation. Preload responsiveness (pulse pressure variation >13%) was observed in 48% of donors (mean +/- sd pulse pressure variation, 19.2% +/- 4.8%). Plasma interleukin-6 and tumor necrosis factor concentrations at study enrollment were greater in preload responsive donors: mean concentrations of interleukin-6 in preload responsive vs. unresponsive donors were 5420 +/- 9102 vs. 378 +/- 631 pg/mL (p = .009), and mean concentrations of tumor necrosis factor were 60.5 +/- 103.6 vs. 15.7 +/- 10.1 pg/mL (p = .048). Preload responsive compared with unresponsive donors had significantly increased interleukin-6 (p = .013) and tumor necrosis factor (p = .044) concentrations over time. Fewer organs were transplanted from preload responsive donors: mean organs transplanted from preload responsive vs. unresponsive donors were 1.8 +/- 0.9 vs. 3.7 +/- 2.5 (p = .034). In multivariable regression, older donor age (p = .028) and increased plasma interleukin-6 concentration (p = .035) were significantly associated with lower number of organs transplanted. CONCLUSIONS: Preload responsiveness is common in brain-dead organ donors and is associated with higher inflammatory response and lower organ yield. A controlled trial of preload optimization is warranted in brain-dead donors.

Increased plasma interleukin-6 in donors is associated with lower recipient hospital-free survival after cadaveric organ transplantation.

OBJECTIVES: Brain death induces a massive inflammatory response. However, the influence of this inflammatory response on organ procurement, transplantation, and recipient outcome is unknown. We describe the inflammatory response characteristics in brain-dead organ donors and examine associations with organ transplantation and recipient survival. We test the hypothesis that increased inflammatory response is associated with fewer organs transplanted and decreased recipient survival. DESIGN: Prospective, observational, cohort study. SETTING: Two large intensive care units of tertiary care university hospitals in the United States. PATIENTS: We recruited 30 consecutive brain-dead organ donors and 78 recipients between April 11, 2004, and November 23, 2004; recipients were followed through May 2005. Following declaration of brain death, we collected data on donor demographics, mechanism of brain death, number of organs procured and transplanted, and recipient characteristics. Plasma cytokines (tumor necrosis factor, interleukin-6, interleukin-10) were measured in donors at baseline following study enrollment, every hour for the first 4 hrs, and immediately before organ procurement for transplantation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We examined the relationships among clinical characteristics, demographics, and cytokine response in donors and their influence on organ procurement and transplantation using multivariable regression and recipient's 6-month hospital-free survival using a Cox proportional hazards regression. One hundred-eighteen organs were procured from 30 donors, and 91 (77%) were transplanted (mean of three organs transplanted per donor). All cytokines were increased following brain death. Older age in donors was significantly associated with lower number of organs transplanted (p < .001). Higher plasma interleukin-6 concentrations in donors before organ procurement was significantly associated with lower 6-month hospital-free survival in recipients (hazard ratio 1.77; 95% confidence interval, 1.17-2.69, p < .007). CONCLUSIONS: Among brain-dead organ donors, older age donors contribute fewer organs for transplantation, and increased donor interleukin-6 level before organ procurement is associated with lower recipient six-month hospital-free survival.

Feasibility study of cytokine removal by hemoadsorption in brain-dead humans.

BACKGROUND: Inflammatory cytokines occur in the circulation and in the tissues after brain death and have been associated with dysfunction of donor organs before and after transplantation. OBJECTIVE: To determine the feasibility of removing cytokines using a hemoadsorption device. DESIGN: Two-center, randomized, open-label, feasibility study in which brain-dead subjects were randomized to two treatment groups. SETTING: Two U.S. academic hospitals. PARTICIPANTS: Eight brain-dead subjects deemed unsuitable for organ donation by respective organ procurement organizations. MAIN OUTCOME MEASURES: After obtaining consent from families, subjects were treated with hemoadsorption for 4 hrs using CytoSorb. Effects on cytokines (tumor necrosis factor, interleukin [IL]-6, and IL-10) were assessed both across the device and in the plasma over time. Feasibility for cytokine removal was assessed using objective criteria. RESULTS: Cytokine removal across the CytoSorb device ranged from 4% to 30% and was not significantly different from 1 hr to 4 hrs. Overall removal was greatest for IL-6, 28% (p = .006), and least for tumor necrosis factor, 8.5% (p = .13). Plasma concentrations of both IL-6 and tumor necrosis factor, but not IL-10, were significantly reduced after the first hour of therapy; mean differences were -13% +/- 7% for IL-6 (p = .039), -23% +/- 9% for tumor necrosis factor (p = .02), and -2% +/- 7% of IL-10 (p = 23). However, plasma concentrations for all three cytokines increased over time and were above baseline by the end of the intervention. No adverse effects of therapy were observed. However, removal of cortisol and triiodothyronine was similar to removal of cytokines. CONCLUSIONS: Hemoadsorption for removal of cytokines in brain-dead subjects is feasible. Evaluation of possible clinical benefit will require controlled trials in actual donors. However, the significant capacity for cytokine removal and absence of adverse events suggest that such trials are warranted.