title: [Expression of tight junction protein claudin-2 in renal tissues and its significance in children with acute kidney injury].
abstract: OBJECTIVE
  To examine changes in expression of tight junction protein claudin-2 in the renal tissues of children with acute kidney injury (AKI), and to investigate the relationship of claudin-2 expression with renal pathological lesion and renal functional lesion.
  
  
  METHODS
  Twenty-four children who were diagnosed with AKI and had renal biopsies between December 2009 and December 2011 were included in the study. These patients were divided into mild AKI (n=7) and severe AKI groups (n=17). Children with isolated hematuria whose renal biopsy showed minor glomerular lesion were selected as the control group. Serum creatinine levels were measured by automatic biochemical analyzer. Tubulointerstitial damage was evaluated by renal pathological scores and expression of claudin-2 was examined by immunohistochemistry. The correlations of claudin-2 expression with renal pathological score and serum creatinine level were assessed by Pearson correlation analysis.
  
  
  RESULTS
  The mild and severe AKI groups had significantly higher serum creatinine levels than the control group (190 ± 68 μmol/L and 477 ± 128 μmol/L vs 29 ± 7 μmol/L, P<0.01), and the severe AKI group had a significantly higher serum creatinine level than the mild AKI group (P<0.01). The tubulointerstitial damage score was significantly lower in the mild AKI group than in the severe AKI group (10.4 ± 1.7 vs 14.0 ± 1.5; P<0.05). The mild and severe AKI groups had significantly smaller areas of claudin-2 expression than the control group (5.0 ± 0.5% and 3.7 ± 0.7% vs 8.0 ± 0.7%; P<0.01), and the severe AKI group had a significantly smaller area of claudin-2 expression than the mild AKI group (P<0.01). The area of claudin-2 expression was negatively correlated with serum creatinine level and tubulointerstitial damage score (r=-0.809 and -0.903; P<0.01).
  
  
  CONCLUSIONS
  There are changes in the distribution and expression of claudin-2 in proximal tubular epithelial cells among children with AKI, and claudin-2 expression is closely related to renal pathological lesion and renal functional lesion.
authors.affiliation: Department of Nephrology and Kidney Laboratory of Hunan Pediatric Research Institute, Hunan Children's Hospital, Changsha 410007, China. Lizh0731@aliyun.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Deng
authors.forename: Yan
authors.initials: Y
authors.lastname: Yin
mesh_terms: D058186:Acute Kidney Injury / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D062446:Claudin-2 / Q000032:analysis*; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D007223:Infant; D007668:Kidney / Q000737:chemistry* / Q000473:pathology; D008297:Male
chemical_list: D062446:Claudin-2; D003404:Creatinine