Assessing GFR With Proenkephalin.

Introduction: In clinical practice, kidney (dys)function is monitored through creatinine-based estimations of glomerular filtration rate (eGFR: Modification of Diet in Renal Disease [MDRD], Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]). Creatinine is recognized as a late and insensitive biomarker of glomerular filtration rate (GFR). The novel biomarker proenkephalin (PENK) may overcome these limitations, but no PENK-based equation for eGFR is currently available. Therefore, we developed and validated a PENK-based equation to assess GFR. Methods: In this international multicenter study in 1354 stable and critically ill patients, GFR was measured (mGFR) through iohexol or iothalamate clearance. A generalized linear model with sigmoidal nonlinear transfer function was used for equation development in the block-randomized development set. Covariates were selected in a data-driven fashion. The novel equation was assessed for bias, precision (mean ± SD), and accuracy (eGFR percentage within ±30% of mGFR, P30) in the validation set and compared with MDRD and CKD-EPI. Results: Median mGFR was 61 [44-81] ml/min per 1.73 m2. In order of importance, PENK, creatinine, and age were included, and sex or race did not improve performance. The PENK-based equation mean ± SD bias of the mGFR was 0.5 ± 15 ml/min per 1.73 m2, significantly less compared with MDRD (8 ± 17, P < 0.001) and 2009 CKD-EPI (5 ± 17, P < 0.001), not reaching statistical significance compared with 2021 CKD-EPI (1.3 ± 16, P = 0.06). The P30 accuracy of the PENK-based equation was 83%, significantly higher compared with MDRD (68%, P < 0.001) and 2009 CKD-EPI (76%, P < 0.001), similar to 2021 CKD-EPI (80%, P = 0.13). Conclusion: Overall, the PENK-based equation to assess eGFR performed better than most creatinine-based equations without using sex or race.

Relationships Between Systemic Inflammation, Intestinal Damage and Postoperative Organ Dysfunction in Adults Undergoing Low-Risk Cardiac Surgery.

BACKGROUND: Approximately half of patients who undergo cardiac surgery develop systemic inflammatory response syndrome. Extracorporeal circulation and intestinal injury may play a role in this inflammatory response, although their relative contributions remain elusive. Moreover, it is largely unknown to what extent these factors contribute to cardiac surgery-induced postoperative organ dysfunction. METHOD: In this secondary analysis, we measured circulating levels of the intestinal damage marker intestinal fatty acid binding protein (I-FABP) and of the inflammatory cytokines tumour necrosis factor (TNF)-α, interleukin (IL)-6, IL-8, IL-10, IL-1RA, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, and MIP-1ß in 180 patients undergoing on-pump cardiac surgery. The average Z-score of levels of the different cytokines was used as an integral measure of the cytokine response. Relationships between duration of extracorporeal circulation, extent of intestinal injury, inflammation, and postoperative organ dysfunction were explored. RESULTS: Plasma I-FABP levels increased during surgery, with peak levels observed at the end of cardiopulmonary bypass (CPB). Except for TNF-α, the levels of all cytokines increased during surgery, with peak levels observed either 2 (MCP-1, MIP-1α, and MIP-1ß), 4 (IL-6, IL-8, and IL-1RA) or 6 (IL-10) hours after the end of CPB. While the duration of CPB significantly correlated with cytokine Z-score (r=0.544, p<0.05), no relationship with I-FABP levels was found. Furthermore, no significant correlations between I-FABP and cytokine levels were observed. The duration of CPB correlated with a deterioration in postoperative kidney function (estimated glomerular filtration rate [eGFR]) and troponin levels. Cytokine Z-score was associated with postoperative troponin levels, fluid administration, inotropic score, pulmonary alveolar-arterial gradient on the first postoperative morning, and deterioration of kidney function (eGFR). I-FABP levels did not correlate with any of the cardiovascular, pulmonary, or renal parameters. CONCLUSIONS: In patients undergoing low-risk cardiac surgery, the duration of CPB represents an important determinant of the systemic cytokine response, whereas both the CPB duration and the systemic inflammatory response contribute to subsequent organ dysfunction. Intestinal damage does not appear to play a relevant role in the postoperative inflammatory response and development of postoperative organ dysfunction in these patients.

Safety and Efficacy of Human Chorionic Gonadotropin Hormone-Derivative EA-230 in Cardiac Surgery Patients: A Randomized Double-Blind Placebo-Controlled Study.

OBJECTIVES: To determine the safety and efficacy of human chorionic gonadotropin hormone-derivative EA-230 in cardiac surgery patients. Cardiac surgery induces systemic inflammation and may impair renal function, affecting patient outcome. EA-230 exerted immunomodulatory and renoprotective effects in preclinical models and was safe and showed efficacy in phase I and II human studies. DESIGN: Double-blinded, placebo-controlled, randomized study. SETTING: Collaboration of the Cardiothoracic Surgery, Anesthesiology, and the Intensive Care departments of a tertiary hospital in the Netherlands. PATIENTS: One hundred eighty patients undergoing an on-pump coronary artery bypass procedure with or without concomitant valve surgery. INTERVENTIONS: Ninety mg/kg/hr EA-230 or placebo administered during surgery. MEASUREMENTS AND MAIN RESULTS: During the study, no safety concerns emerged. EA-230 did not modulate interleukin-6 plasma concentrations (area under the curve 2,730 pg/mL × hr [1,968-3,760] vs 2,680 pg/mL × hr [2,090-3,570] for EA-230 and placebo group, respectively; p = 0.80). Glomerular filtration rate increased following surgery (mean ± sem increase in the EA-230 vs placebo groups: glomerular filtration rateiohexol measured using iohexol plasma clearance: 19 ± 2 vs 16 ± 2 mL/min/1.73 m2; p = 0.13 and estimated glomerular filtration rate with the Modification of Diet in Renal Disease equation using creatinine: 6 ± 1 vs 2 ± 1 mL/min/1.73 m2; p = 0.01). The "injury" stage of the Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease criteria for acute kidney injury was 7% in the EA-230 group versus 18% in the placebo group (p = 0.07). In addition, EA-230-treated patients had a less positive fluid balance compared with placebo-treated patients (217 ± 108 vs 605 ± 103 mL; p = 0.01), while the use of vasoactive agents was similar in both groups (p = 0.39). Finally, hospital length of stay was shorter in EA-230 treated patients (8 d [7-11] vs 10 d [8-12]; p = 0.001). Efficacy results were more pronounced in patients that had longer duration of surgery and thus longer duration of study drug infusion. CONCLUSIONS: EA-230 was safe in patients undergoing on-pump cardiac surgery. It did not modulate interleukin-6 plasma concentrations but appeared to exert beneficial renal and cardiovascular effects and shortened in-hospital length of stay.

Endotoxemia-Induced Release of Pro-inflammatory Mediators Are Associated With Increased Glomerular Filtration Rate in Humans in vivo.

Introduction: Sepsis is the most prevalent cause of Acute Kidney Injury (AKI). Conversely, in some septic patients the glomerular filtration rate (GFR) is augmented. The role of the inflammatory response and blood pressure to induce this increased GFR is unknown. Herein, we relate inflammatory mediators and blood pressure to the iohexol clearance-derived "true" GFR and kidney injury markers during systemic inflammation in healthy volunteers. Methods: Twelve healthy subjects underwent experimental endotoxemia (i.v. administration of 2 ng/kg Escherichia coli-derived lipopolysaccharide, LPS). As a gold-standard to determine the GFR, iohexol plasma clearance (GFRiohexol) was calculated during a 6-h period on the day before (baseline) as well as 2 and 24 h after LPS administration. Intra-arterial blood pressure was recorded continuously using a radial artery catheter. Circulating inflammatory mediators and urinary excretion of kidney injury markers were serially measured. Results: Experimental endotoxemia profoundly increased plasma concentrations of inflammatory mediators, including [mean ± SD or median [IQR] peak values (pg/mL) of tumor necrosis factor (TNF)-α: 92 ± 40, interleukin (IL)-6: 1,246 ± 605, IL-8: 374 ± 120, IL-10: 222 ± 119, IL-1 receptor antagonist (RA): 8,955 ± 2,429, macrophage chemoattractant protein (MCP)-1: 2,885 [2,706 - 3,765], vascular adhesion molecule (VCAM)-1: 296,105 ± 34,822, intercellular adhesion molecule (ICAM)-1: 25,0170 ± 41,764]. Mean arterial pressure decreased with 13 ± 11 mmHg (p < 0.0001). No significant increase in the urinary excretion of tubular injury markers was observed following LPS administration. GFRiohexol increased from 97 ± 6 at baseline to 118 ± 10 mL/min/1.73m2 (p < 0.0001) post-LPS administration and returned to baseline levels at 24 h post-LPS (99 ± 9 mL/min/1.73m2). Peak plasma concentrations of IL-6 (R 2 = 0.66, p = 0.001) and IL-8 (R 2 = 0.51, p = 0.009), MCP-1 (R 2 = 0.38, p = 0.03) and VCAM-1 levels (R 2 = 0.37, p = 0.04) correlated with the increase in GFRiohexol, whereas a trend was observed for TNF-α (R 2 = 0.33, p = 0.0509) and IL-1RA (R 2 = 0.28, p = 0.08). None of the kidney injury markers or changes in blood pressure were associated with GFRiohexol. In multiple linear regression analysis, both peak IL-6 (p = 0.002) and IL-8 (p = 0.01) concentrations remained significantly correlated with GFRiohexol, without collinearity. Discussion: Concentrations of pro-inflammatory cytokines, but not blood pressure, are correlated with the endotoxemia-induced increase in GFR in healthy volunteers. These findings may indicate that inflammatory mediators orchestrate the augmented GFR observed in a subgroup of sepsis patients.

Proenkephalin Compared to Conventional Methods to Assess Kidney Function in Critically Ill Sepsis Patients.

BACKGROUND: The assessment of renal function in clinical practice remains challenging. Using creatinine to assess the glomerular filtration rate (GFR) is notoriously inaccurate, and determination of the true GFR, e.g., using inulin or iohexol, is laborious and not feasible in daily practice. Proenkephalin (PENK) is a novel candidate biomarker for kidney function that is filtrated in the glomerulus, has shown to represent steady-state GFR in patients with different severities of renal insufficiency. In this pilot study in non-steady-state critically ill patients, we compared plasma PENK concentrations with creatinine-based GFR assessments and validated both against the "true GFR" measured using a gold standard method: iohexol plasma clearance. METHODS: Twenty-three critically ill patients with septic shock were included. Kidney function was determined using the Modification of Diet in Renal Disease formula (eGFRMDRD), Endogenous Creatinine Clearance (GFRECC), and iohexol plasma clearance (GFRiohexol) during a 6-h window. Plasma PENK concentrations were measured using the penKid immunoassay. RESULTS: The eGFRMDRD and GFRECC correlated with the GFRiohexol (R = 0.82, P < 0.0001 and R = 0.82, P < 0.0001 respectively); however, bias and variability were considerable: the eGFRMDRD overestimated the true GFR with 31 ±â€Š35% (95% limits of agreement: -37% to 100%) and the GFRECC with 37 ±â€Š49% (95% limits of agreement: -59% to 133%). Plasma PENK concentrations showed a very strong inverse correlation with the GFRiohexol (R = 0.90, P < 0.0001) which tended to be better compared with the correlation of eGFRMDRD (P = 0.06) and GFRECC (P = 0.08) with the GFRiohexol. CONCLUSIONS: In this pilot study in non-steady-state critically ill sepsis patients, GFR appears to be more accurately reflected by plasma PENK concentrations compared to conventional creatinine-based methods. Therefore, PENK holds promise as an accurate and feasible biomarker to determine kidney function during non-steady-state conditions in the critically ill.

The Human Chorionic Gonadotropin Derivate EA-230 Modulates the Immune Response and Exerts Renal Protective Properties: Therapeutic Potential in Humans.

The extent of the systemic inflammatory response following infectious or noninfectious insults is related to impaired patient outcome. Pregnancy is associated with immunotolerance and an increased glomerular filtration rate. EA-230 is a newly developed synthetic linear tetrapeptide derived from the "pregnancy hormone" human chorionic gonadotropin. In this review, we describe the immunomodulatory and renoprotective properties of EA-230 in preclinical animal models, phase 1 studies in humans and phase 2a studies performed during human experimental endotoxemia. In addition, details pertaining to the design of a recently completed phase 2b study in 180 patients who underwent cardiac surgery to investigate the safety and immunomodulatory and renoprotective properties of EA-230 are discussed.

Pharmacokinetics, safety and tolerability of the novel ß-hCG derived immunomodulatory compound, EA-230.

AIMS: EA-230 is a newly developed synthetic linear tetrapeptide (AQGV) derived from the chorionic gonadotropin hormone (ß-hCG). We investigated the pharmacokinetics, safety and tolerability of EA-230 in healthy subjects using different administration strategies. METHODS: Double-blind, randomized, placebo-controlled, dose-escalating phase I studies in healthy subjects using intravenous administration were conducted. In the single dosage study, 32 subjects were assigned to four single dosage groups (1, 3, 10 or 30 mg/kg). In the multiple dosage study, 24 subjects were assigned to three dosage groups (10, 20 or 30 mg/kg, thrice daily for 3 days). In the continuous dosage study, 24 subjects were assigned to three dosage groups (15, 30, or 90 mg/kg/hour for 2 hours). Pharmacokinetics, safety and tolerability assessments were performed up to 14 days. RESULTS: The highest dosage of EA-230 (continuous infusion of 90 mg/kg/hour for 2 hours) showed more than proportional increases in exposure (Cmax 136%; AUC0-last 137%), a large volume of distribution (geometric mean and 95% CI: 13 [3-58] L/kg), a high clearance rate (26 [15-43] L/h/kg), and a short half-life (0.35 [0.13-1.0] minutes). EA-230 was well tolerated and no safety concerns were observed. CONCLUSION: These dose-escalating phase I studies with different administration strategies reveal a pharmacokinetic profile of EA-230 with a large volume of distribution and a short half-life. Furthermore, EA-230 was well tolerated and no safety issues emerged. These results have enabled further clinical development in a phase IIa trial assessing the pharmacodynamics of this compound during systemic inflammation described elsewhere in this issue.

A randomized double-blind, placebo-controlled clinical phase IIa trial on safety, immunomodulatory effects and pharmacokinetics of EA-230 during experimental human endotoxaemia.

AIMS: EA-230 is a human chorionic gonadotropin hormone-derived linear tetrapeptide, developed for the treatment of systemic inflammation-related disorders. EA-230 has shown promising immunomodulatory and tissue-protective effects in animals and an excellent safety profile in human phase I studies that we performed. The present phase IIa study follows-up on these results by investigating the safety, efficacy and pharmacokinetics of EA-230 under systemic inflammatory conditions induced by experimental human endotoxaemia. METHODS: In this randomized, double blind, placebo-controlled phase IIa study, systemic inflammation was induced by intravenous administration of Escherichia coli-derived lipopolysaccharide (LPS). At t = 0 hours, 36 healthy male volunteers received 2 ng/kg LPS, followed by a 2-hour continuous infusion of EA-230 (15, 45 and 90 mg/kg/h, n = 8 per group) or placebo (n = 12). RESULTS: EA-230 was well tolerated and showed a favourable safety profile. Treatment with the highest dose of EA-230 resulted in a significant attenuation of the LPS-induced increase in plasma levels of inflammatory mediators interleukin (IL)-6, IL-8, IL-1 receptor antagonist, monocyte chemoattractant protein-1, macrophage inflammatory proteins-1α and -1ß, and vascular cell adhesion protein-1 (% reduction of 48, 28, 33, 28, 14, 16 and 19 respectively, p < .01), and reduced fever (peak decrease from 1.8 ± 0.1°C to 1.3 ± 0.2°C, P < .05) and symptom scores (peak decrease from 7.4 ± 1.0 to 4.0 ± 1.2 points, P < .05). EA-230 exhibited a very short elimination half-life and a large volume of distribution in the highest dosage group (geometric mean and 95% confidence interval: 0.17 [0.12-0.24] hours and 2.2 [1.3-3.8] L/kg, respectively). CONCLUSION: Administration of EA-230 is safe and results in attenuation of the systemic inflammatory response in humans.

The Safety, Tolerability, and Effects on the Systemic Inflammatory Response and Renal Function of the Human Chorionic Gonadotropin Hormone-Derivative EA-230 Following On-Pump Cardiac Surgery (The EASI Study): Protocol for a Randomized, Double-Blind, Placebo-Controlled Phase 2 Study.

BACKGROUND: The cardiac surgery-induced systemic inflammatory response may induce postoperative hemodynamic instability and impairment of renal function. EA-230, a linear tetrapeptide (A-Q-G-V), is derived from the beta chain of the human chorionic gonadotropin pregnancy hormone. It has shown immunomodulatory and renoprotective effects in several animal models of systemic inflammation. In phase 1 and phase 2a studies, these immunomodulatory effects were confirmed during human experimental endotoxemia, and EA-230 was found to have an excellent safety profile. OBJECTIVE: The objective of this first in-patient study is to test the safety and tolerability as well as the immunomodulatory and renoprotective effects of EA-230 in a proof-of-principle design in patients with systemic inflammation following on-pump cardiac surgery. METHODS: We describe a prospective, randomized, double-blind, placebo-controlled study in which 180 elective patients undergoing on-pump coronary artery bypass grafting, with or without concomitant valve surgery, are enrolled. Patients will be randomized in a 1:1 ratio and will receive either EA-230 (90 mg/kg/hour) or a placebo. These will be infused at the start of the surgical procedure until the end of the use of the cardiopulmonary bypass. The primary focus of this first-in-patient study will be on safety and tolerability of EA-230. The primary efficacy end point is the modulation of the inflammatory response by EA-230 quantified as the change in interleukin-6 plasma concentrations after surgery. The key secondary end point is the effect of EA-230 on renal function. The study will be conducted in 2 parts to enable an interim safety analysis by an independent data monitoring committee at a sample size of 60. An adaptive design is used to reassess statistical power halfway through the study. RESULTS: This study has been approved by the independent competent authority and ethics committee and will be conducted in accordance with the ethical principles of the Declaration of Helsinki, guidelines of Good Clinical Practice, and European Directive 2001/20/CE regarding the conduct of clinical trials. Results of this study will be submitted for publication in a peer-reviewed scientific journal. Enrollment of this study commenced in July 2016, and results are expected at the end of 2018. CONCLUSIONS: This adaptive phase 2 clinical study is designed to test the safety and tolerability of EA-230 in patients undergoing cardiac surgery. In addition, efficacy end points focused on the effect of the systemic inflammatory response and renal function are investigated. TRIAL REGISTRATION: ClinicalTrials.gov NCT03145220; https://clinicaltrials.gov/ct2/show/NCT03145220 (Archived by WebCite at http://www.webcitation.org/74JPh8GNN). INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/11441.

Immunomodulatory and Kidney-Protective Effects of the Human Chorionic Gonadotropin Derivate EA-230.

The systemic inflammatory response following infectious or non-infectious insults is related to morbidity (including acute kidney injury) and mortality. Pregnancy is associated with immunotolerance and an increased glomerular filtration rate. EA-230, a linear tetrapeptide (Alanine-Glutamine-Glycine-Valine), derived from the ß-chain of the human chorionic gonadotropin hormone, has shown immunomodulatory and renoprotective properties in several pre-clinical animal models of systemic inflammation. Furthermore, an excellent safety profile of EA-230 was observed in phase 1 studies in humans, and the immunomodulatory effects of EA-230 were recently demonstrated in a phase IIa study during human experimental endotoxemia. A prospective double-blind placebo-controlled randomized trial in 180 patients undergoing elective CABG-surgery with or without valve surgery is currently conducted to investigate the immunomodulatory and renoprotective properties of EA-230.

Monocyte Subsets Are Differentially Lost from the Circulation during Acute Inflammation Induced by Human Experimental Endotoxemia.

Three human monocyte subsets are recognized with different functions in the immune system: CD14++/CD16- classical monocytes (CM), CD14++/CD16+ intermediate monocytes (IM) and CD14+/CD16++ non-classical monocytes (NCM). Increased IM and NCM percentages have been reported under inflammatory conditions, yet little is known about monocyte subsets at the onset of inflammation. The human endotoxemia model is uniquely capable of studying the first phases of acute inflammation induced by intravenous injection of 2 ng/kg bodyweight lipopolysaccharide (LPS) into healthy volunteers. After that, monocyte subset counts, activation/differentiation status and chemokine levels were studied over 24 h. The numbers of all subsets were decreased by >95% after LPS injection. CM numbers recovered first (3- 6 h), followed by IM (6-8 h) and NCM numbers (8-24 h). Similarly, increased monocyte counts were observed first in CM (8 h), followed by IM and NCM (24 h). Monocytes did not display a clear activated phenotype (minor increase in CD11b and CD38 expression). Plasma levels of CCL2, CCL4 and CX3CL1 closely resembled the cell numbers of CM, IM and NCM, respectively. Our study provides critical insights into the earliest stages of acute inflammation and emphasizes the necessity to stain for different monocyte subsets when studying the role of monocytes in disease, as neither function nor kinetics of the subsets overlap.