title: Clinicopathologic Impact of Early Medullary Ray Injury in Patients Following Kidney Transplantation.
abstract: BACKGROUND
  Previously, we explored the histopathologic characteristics of medullary ray injury (MRI) inducing interstitial fibrosis and tubular atrophy (IF/TA) to determine its etiologies, which include calcineurin inhibitor (CNI) toxicity and urologic complications. However, we did not examine the effects of these etiologies on long-term kidney allograft prognosis, because biopsy timing differed among cases.
  
  
  OBJECTIVE
  We examined the influence of early MRI on kidney allograft prognosis using protocol biopsies taken within a 3-month time frame.
  
  
  METHODS
  We defined early MRI as tubular degeneration with interstitial edema or mild fibrosis localized to the medullary ray. We divided 53 protocol biopsies into 2 groups, with and without early MRI. Early MRI+ cases with isometric vacuolization were classified as CNI toxicity; those with Tamm-Horsfall protein in the interstitium and a thyroidlike appearance were classified as urinary tract system abnormalities; remaining cases were classified as "others." We compared changes in serum levels of creatinine (sCr) over 3 years and fibrosis extent at 1 year.
  
  
  RESULTS
  The sCr levels were significantly higher in the MRI+ group than the MRI- group at 3 years (P = .024). Examining the 3 MRI+ subgroups, only the MRI+ urinary tract system abnormalities group had significantly high sCr levels compared to the MRI- group (P = .019). The MRI+ group showed significant signs of IF/TA at 1 year.
  
  
  CONCLUSIONS
  Early MRI after kidney transplantation was significantly more likely to develop IF/TA at 1 year and had higher sCr levels at 3 years. In such cases, intervention might preserve graft function over the long term.
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Niikura
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan. Electronic address: akimitsu@kk.iij4u.or.jp.
authors.forename: A
authors.initials: A
authors.lastname: Kobayashi
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kawabe
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Katsuma
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamakawa
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Katsumata
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mafune
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakada
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Yamamoto
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tanno
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Ohkido
authors.affiliation: Department of Urology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okumi
authors.affiliation: Department of Urology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ishida
authors.affiliation: Department of Internal Medicine, Atsugi City Hospital, Kanagawa, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.affiliation: Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yokoo
authors.affiliation: Department of Urology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tanabe
mesh_terms: D000328:Adult; D001706:Biopsy; D003404:Creatinine / Q000097:blood; D005260:Female; D005355:Fibrosis / Q000473:pathology; D006084:Graft Rejection / Q000473:pathology*; D006801:Humans; D007668:Kidney / Q000473:pathology*; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged
chemical_list: D003404:Creatinine