BACKGROUND: Open heart surgery with cardiopulmonary bypass is recognized as a common cause of acute kidney injury (AKI). The conventional biomarker creatinine is not sensitive enough to detect AKI until a significant decline in renal filtration has occurred. Urine neutrophil gelatinase-associated lipocalin (NGAL), part of an acute response to the release of tissue iron from cells, is an early biomarker and a predictor of AKI in a variety of clinical settings. We sought to evaluate the relationship between urine catalytic iron (unbound iron) and NGAL over the course of AKI due to cardiac surgery. METHODS: FOURTEEN PATIENTS WHO UNDERWENT OPEN HEART SURGERY HAD THE FOLLOWING MEASURED: serum creatinine (0, 12, 24, 48 and 72 h postoperatively), urine NGAL and urine catalytic iron (0, 8, 24 and 48 h postoperatively). Urine NGAL and urine catalytic iron were quantified by immunoassay and bleomycin-detectable iron assay, respectively. AKI was defined by the Acute Kidney Injury Network (AKIN) criteria. RESULTS: Urine catalytic iron increased significantly (p < 0.05) within 8 h and peaked at 24 h postoperatively in patients who developed AKI (n = 8, baseline 101.96 ± 177.48, peak 226.35 ± 238.23 nmol/l, p = 0.006), but not in non-AKI patients (n = 6, baseline 131.08 ± 116.21, peak 163.99 ± 109.62 nmol/l, p = 0.380). Urine NGAL levels also peaked at 24 h with significant increase observed only in AKI patients: AKI - baseline 34.88 ± 26.47, peak 65.50 ± 27.03 ng/ml, p = 0.043; non-AKI - baseline 59.33 ± 31.72, peak 71.00 ± 31.76 ng/ml, p = 0.100. The correlation between baseline levels of urine catalytic iron and NGAL and peak levels of urine catalytic iron and NGAL was r = 0.86, p < 0.0001. CONCLUSION: Urine catalytic iron appears to rise and fall in concert with NGAL in patients undergoing cardiac surgery and may be indicative of early AKI. Future research into the role that catalytic iron plays in acute organ injury syndromes and its potential diagnostic and therapeutic implications is warranted.
BACKGROUND: Open heart surgery with cardiopulmonary bypass is recognized as a common cause of acute kidney injury (AKI). The conventional biomarker creatinine is not sensitive enough to detect AKI until a significant decline in renal filtration has occurred. Urine neutrophil gelatinase-associated lipocalin (NGAL), part of an acute response to the release of tissue iron from cells, is an early biomarker and a predictor of AKI in a variety of clinical settings. We sought to evaluate the relationship between urine catalytic iron (unbound iron) and NGAL over the course of AKI due to cardiac surgery. METHODS: FOURTEEN PATIENTS WHO UNDERWENT OPEN HEART SURGERY HAD THE FOLLOWING MEASURED: serum creatinine (0, 12, 24, 48 and 72 h postoperatively), urine NGAL and urine catalytic iron (0, 8, 24 and 48 h postoperatively). Urine NGAL and urine catalytic iron were quantified by immunoassay and bleomycin-detectable iron assay, respectively. AKI was defined by the Acute Kidney Injury Network (AKIN) criteria. RESULTS: Urine catalytic iron increased significantly (p < 0.05) within 8 h and peaked at 24 h postoperatively in patients who developed AKI (n = 8, baseline 101.96 ± 177.48, peak 226.35 ± 238.23 nmol/l, p = 0.006), but not in non-AKI patients (n = 6, baseline 131.08 ± 116.21, peak 163.99 ± 109.62 nmol/l, p = 0.380). Urine NGAL levels also peaked at 24 h with significant increase observed only in AKI patients: AKI - baseline 34.88 ± 26.47, peak 65.50 ± 27.03 ng/ml, p = 0.043; non-AKI - baseline 59.33 ± 31.72, peak 71.00 ± 31.76 ng/ml, p = 0.100. The correlation between baseline levels of urine catalytic iron and NGAL and peak levels of urine catalytic iron and NGAL was r = 0.86, p < 0.0001. CONCLUSION: Urine catalytic iron appears to rise and fall in concert with NGAL in patients undergoing cardiac surgery and may be indicative of early AKI. Future research into the role that catalytic iron plays in acute organ injury syndromes and its potential diagnostic and therapeutic implications is warranted.
Authors: Chenell Donadee; Nicolaas J H Raat; Tamir Kanias; Jesús Tejero; Janet S Lee; Eric E Kelley; Xuejun Zhao; Chen Liu; Hannah Reynolds; Ivan Azarov; Sheila Frizzell; E Michael Meyer; Albert D Donnenberg; Lirong Qu; Darrel Triulzi; Daniel B Kim-Shapiro; Mark T Gladwin Journal: Circulation Date: 2011-07-11 Impact factor: 29.690
Authors: Glenn M Chertow; Elisabeth Burdick; Melissa Honour; Joseph V Bonventre; David W Bates Journal: J Am Soc Nephrol Date: 2005-09-21 Impact factor: 10.121
Authors: H Kulaksiz; F Theilig; S Bachmann; S G Gehrke; D Rost; A Janetzko; Y Cetin; W Stremmel Journal: J Endocrinol Date: 2005-02 Impact factor: 4.286
Authors: R Bellomo; S Auriemma; A Fabbri; A D'Onofrio; N Katz; P A McCullough; Z Ricci; A Shaw; C Ronco Journal: Int J Artif Organs Date: 2008-02 Impact factor: 1.595
Authors: David M Charytan; Steven Fishbane; Jolanta Malyszko; Peter A McCullough; David Goldsmith Journal: Am J Kidney Dis Date: 2015-02-26 Impact factor: 8.860
Authors: David E Leaf; Mohan Rajapurkar; Suhas S Lele; Banibrata Mukhopadhyay; James D Rawn; Gyorgy Frendl; Sushrut S Waikar Journal: Kidney Int Date: 2015-01-07 Impact factor: 10.612
Authors: David E Leaf; Mohan Rajapurkar; Suhas S Lele; Banibrata Mukhopadhyay; Emily A S Boerger; Finnian R Mc Causland; Michele F Eisenga; Karandeep Singh; Jodie L Babitt; John A Kellum; Paul M Palevsky; Marta Christov; Sushrut S Waikar Journal: J Am Soc Nephrol Date: 2019-02-08 Impact factor: 10.121
Authors: David E Leaf; Mohan Rajapurkar; Suhas S Lele; Banibrata Mukhopadhyay; Sushrut S Waikar Journal: Clin J Am Soc Nephrol Date: 2014-09-04 Impact factor: 8.237
Authors: Kristen M Tecson; Elisabeth Erhardtsen; Peter M Eriksen; A Osama Gaber; Michael Germain; Ladan Golestaneh; Maria de Los Angeles Lavoria; Linda W Moore; Peter A McCullough Journal: BMJ Open Date: 2017-07-10 Impact factor: 2.692