title: Early urinary angiotensinogen excretion in critically ill neonates.
abstract: BACKGROUND
  Urinary angiotensinogen is considered a reliable biomarker for intrarenal renin-angiotensin system activity. The aims of this study were to assess the urinary angiotensinogen level during the first day of life and to evaluate its correlation with renal function in critically ill neonates.
  
  
  METHODS
  Urinary angiotensinogen concentration during the first 24 hours of life was measured in 98 critically ill neonates. Neonatal renal function was assessed by urinary levels of cystatin-C, albumin and α1-microglobulin and urinary electrolyte excretion.
  
  
  RESULTS
  Urinary angiotensinogen level decreased with increasing gestational age and body weight in critically ill neonates (P<0.001). After adjustment for gestational age, urinary angiotensinogen level correlated with urinary fractional excretion of sodium and urinary levels of cystatin-C and α1-microglobulin. Multivariate linear regression identified a significant impact of urinary cystatin-C on urinary angiotensinogen level (P<0.001). Furthermore, urinary angiotensinogen was significantly increased in neonates with a urinary cystatin-C-to-creatinine ratio ⩾2500 ng/mg, which was the optimal cut-off value to predict acute kidney injury in our previous study.
  
  
  CONCLUSIONS
  The urinary angiotensinogen level correlates with the overall maturity of renal function during the early postnatal period in critically ill neonates and an increased urinary angiotensinogen level might reflect renal injury in immature neonates.
authors.affiliation: Department of Neonatology, Children's Hospital affiliated to Soochow University, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Nephrology, Children's Hospital affiliated to Soochow University, China.
authors.forename: Mengxia
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Nephrology, Children's Hospital affiliated to Soochow University, China.
authors.forename: Xiaozhong
authors.initials: X
authors.lastname: Li
authors.affiliation: Institute of Pediatric Research, Children's Hospital affiliated to Soochow University, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Pan
authors.affiliation: Institute of Pediatric Research, Children's Hospital affiliated to Soochow University, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Neonatology, Children's Hospital affiliated to Soochow University, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Feng
authors.affiliation: Department of Nephrology, Children's Hospital affiliated to Soochow University, China Institute of Pediatric Research, Children's Hospital affiliated to Soochow University, China lyh072006@hotmail.com.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Li
mesh_terms: D000419:Albuminuria / Q000097:blood / Q000150:complications; D000510:Alpha-Globulins / Q000652:urine; D000808:Angiotensinogen / Q000097:blood / Q000652:urine*; D001835:Body Weight; D003404:Creatinine / Q000652:urine; D016638:Critical Illness; D055316:Cystatin C / Q000652:urine; D004573:Electrolytes / Q000652:urine; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D015999:Multivariate Analysis; D011188:Potassium / Q000652:urine; D012964:Sodium / Q000652:urine
chemical_list: D000510:Alpha-Globulins; D055316:Cystatin C; D004573:Electrolytes; C016001:alpha-1-microglobulin; D000808:Angiotensinogen; D012964:Sodium; D003404:Creatinine; D011188:Potassium
keywords: Acute kidney injury; critically ill neonates; renal function; renin–angiotensin system; urinary angiotensinogen; urinary cystatin-C; urinary fractional excretion of electrolytes