title: Renal Klotho expression in patients with acute kidney injury is associated with the severity of the injury.
abstract: OBJECTIVE
  The potential physiologic roles of Klotho in acute kidney injury (AKI) have recently been demonstrated in animal models. However, to date, there have been no human studies investigating the expression of renal Klotho in AKI.
  
  
  METHODS
  We retrospectively collected biopsy specimens and clinical data of AKI patients between January 2001 and December 2012. Klotho expression was determined by immunohistochemical staining, and the clinical-pathological correlation was examined.
  
  
  RESULTS
  Among the 34 patients diagnosed with acute tubular necrosis or acute tubulointerstitial nephritis, 21 patients without chronic histological lesions were included. The mean age was 37.3 ± 18.5 years and the mean peak creatinine level was 8.2 ± 5.5 mg/dL. In total, 10 patients (47.6%) received temporary renal replacement therapy (RRT); however, 17 patients (81%) showed functional recovery with creatinine levels of < 1.3 mg/dL after 1 month. The intensity of Klotho expression was scored as a percentage of Klotho-positive area. The renal Klotho score showed a significant negative correlation with the initial or peak creatinine level. When the patients were divided into three groups according to the Klotho score (low, middle, high), the low group had a significantly higher peak creatinine level and a more frequent requirement for RRT. However, the Klotho score was not a significant predictor of renal recovery.
  
  
  CONCLUSIONS
  The results demonstrated that renal Klotho expression in humans decreased significantly according to the severity of AKI, regardless of the etiology, and that low expression was associated with a poor short-term outcome.
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Min Young
authors.initials: MY
authors.lastname: Seo
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Jihyun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Jun Yong
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Kitae
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Sun Chul
authors.initials: SC
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Hyojeong
authors.initials: H
authors.lastname: Chang
authors.affiliation: Department of Pathology, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Nam Hee
authors.initials: NH
authors.lastname: Won
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Myung-Gyu
authors.initials: MG
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Sang-Kyung
authors.initials: SK
authors.lastname: Jo
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Wonyong
authors.initials: W
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Hyoung Kyu
authors.initials: HK
authors.lastname: Kim
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D015536:Down-Regulation; D005260:Female; D005966:Glucuronidase / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000737:chemistry* / Q000473:pathology / Q000503:physiopathology; D007683:Kidney Tubular Necrosis, Acute / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy; D000090265:Klotho Proteins; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D011237:Predictive Value of Tests; D020127:Recovery of Function; D017582:Renal Replacement Therapy; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005966:Glucuronidase; D000090265:Klotho Proteins
keywords: Acute kidney injury; Acute tubular necrosis; Klotho