title: Renal resistive index correlates with peritubular capillary loss and arteriosclerosis in biopsy tissues from patients with chronic kidney disease.
abstract: BACKGROUND
  The renal resistive index (RI) is a Doppler-derived measure that reportedly correlates with renal histological changes and renal disease severity and outcome. The aim of this study was to investigate the factors related to the RI elevation in chronic kidney disease (CKD).
  
  
  METHODS
  Using Doppler ultrasonography, RIs were determined in 30 patients with CKD, after which they were correlated with interstitial fibrosis, arteriosclerosis, arteriolosclerosis and peritubular capillary (PTC) density. PTC-positive areas were determined based on CD34 immunostaining. Interstitial fibrosis was detected with Masson trichrome staining. All histological markers were assessed using quantitative and semi-quantitative analyses and evaluated statistically using Pearson correlation tests, unpaired t tests and stepwise multiple regression analysis.
  
  
  RESULTS
  RI correlated positively with age (r = 0.603, p = 0.0004), systolic blood pressure (r = 0.775, p < 0.0001), diastolic blood pressure (r = 0.575, p = 0.001), interstitial fibrosis (r = 0.381, p = 0.038) and arteriosclerosis (r = 0.520, p = 0.003), and negatively with creatinine clearance (r = -0.471, p = 0.009) and CD34+ (PTC) areas (r = -0.437, p = 0.016). Patients with hypertension or diabetes mellitus showed higher RIs (p < 0.05) than those without the ailments. Multivariate analysis showed PTC and arteriosclerosis to be independent variables correlating with RI (r (2) = 0.321, p < 0.05).
  
  
  CONCLUSIONS
  To our knowledge, this is the first report of using RI measurements to evaluate peritubular capillary loss. Our findings indicate that increases in RI are associated with both arteriosclerosis and loss of PTCs.
authors.affiliation: Division of Nephrology, Department of General Medicine, University of Fukui, 23-3 Shimoaizuki, Matsuoka, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan. nopoisute55@yahoo.co.jp.|Department of Internal Medicine, Fukui Kosei Hospital, Shimorokujyo-cho 201, Fukui, 918-8537, Japan. nopoisute55@yahoo.co.jp.
authors.forename: Noriyo
authors.identifier: http://orcid.org/0000-0003-3022-0365
authors.initials: N
authors.lastname: Kimura
authors.affiliation: Department of Clinical Laboratoriesm, Fukui, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Division of Nephrology, Department of General Medicine, University of Fukui, 23-3 Shimoaizuki, Matsuoka, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Clinical Laboratoriesm, Fukui, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Hamada
authors.affiliation: Division of Surgical Pathology, University of Fukui Hospital, Fukui, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Maegawa
authors.affiliation: Division of Surgical Pathology, University of Fukui Hospital, Fukui, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.affiliation: Division of Surgical Pathology, University of Fukui Hospital, Fukui, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Imamura
authors.affiliation: Department of Public Health, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Kusaka
authors.affiliation: Sugita Genpaku Memorial Obama Municipal Hospital, Fukui, Japan.
authors.forename: Haruyoshi
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Division of Nephrology, Department of General Medicine, University of Fukui, 23-3 Shimoaizuki, Matsuoka, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Iwano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology; D018952:Antigens, CD34 / Q000652:urine; D001161:Arteriosclerosis / Q000473:pathology*; D001706:Biopsy; D001794:Blood Pressure; D002196:Capillaries / Q000473:pathology*; D005260:Female; D005355:Fibrosis / Q000473:pathology; D006801:Humans; D007677:Kidney Function Tests; D007684:Kidney Tubules / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000000981:diagnostic imaging* / Q000473:pathology*; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance; D055815:Young Adult
chemical_list: D018952:Antigens, CD34
keywords: Arteriosclerosis; Chronic kidney disease; Peritubular capillaries; Renal resistive index