title: Evolution of bone disease after kidney transplantation: A prospective histomorphometric analysis of trabecular and cortical bone.
abstract: OBJECTIVE
  Post-transplant bone disease results from multiple factors, including previous bone and mineral metabolism disturbances and effects from transplant-related medications. Bone biopsy remains the gold-standard diagnostic tool.
  
  
  METHODS
  We aimed to prospectively evaluate trabecular and cortical bone by histomorphometry after kidney transplantation. Seven patients, willing to perform follow-up bone biopsy, were included in the study. Dual-X-ray absorptiometry and trans-iliac bone biopsy were performed within the first 2 months after renal transplantation and repeated after 2-5 years of follow-up.
  
  
  RESULTS
  Follow-up biopsy revealed a significant decrease in osteoblast surface/bone surface (0.91 ± 0.81 to 0.47 ± 0.12%, P = 0.036), osteoblasts number/bone surface (0.45 (0.23, 0.94) to 0.00/mm(2) , P = 0.018) and erosion surface/bone surface (3.75 ± 2.02 to 2.22 ± 1.38%, P = 0.044). A decrease in trabecular number (3.55 (1.81, 2.89) to 1.55/mm (1.24, 2.06), P = 0.018) and increase in trabecular separation (351.65 ± 135.04 to 541.79 ± 151.91 μm, P = 0.024) in follow-up biopsy suggest loss in bone quantity. We found no significant differences in cortical analysis, except a reduction in external cortical osteonal eroded surface (5.76 (2.94, 13.97) to 3.29% (0.00, 6.67), P = 0.043). Correlations between bone histomorphometric and dual-X-ray absorptiometry parameters gave inconsistent results.
  
  
  CONCLUSIONS
  The results show a reduction in bone activity, suggesting increased risk of adynamic bone and loss of bone volume. Cortical bone seems less affected by post-transplant biological changes in the first years after kidney transplantation.
authors.affiliation: Nephrology and Infectiology Research and Development Group, INEB, Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Carvalho
authors.affiliation: Nephrology and Infectiology Research and Development Group, INEB, Porto, Portugal.
authors.forename: Juliana
authors.initials: J
authors.lastname: Magalhães
authors.affiliation: Nephrology and Infectiology Research and Development Group, INEB, Porto, Portugal.
authors.forename: Luciano
authors.initials: L
authors.lastname: Pereira
authors.affiliation: Nephrology Research and Development Unit, Medical School, Porto University, Porto, Portugal.
authors.forename: Liliana
authors.initials: L
authors.lastname: Simões-Silva
authors.affiliation: Nephrology Research and Development Unit, Medical School, Porto University, Porto, Portugal.
authors.forename: Inês
authors.initials: I
authors.lastname: Castro-Ferreira
authors.affiliation: Nephrology and Infectiology Research and Development Group, INEB, Porto, Portugal.
authors.forename: João Miguel
authors.initials: JM
authors.lastname: Frazão
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D001706:Biopsy; D015519:Bone Density; D001847:Bone Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D016723:Bone Remodeling; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome
keywords: bone and bones/pathology; bone biopsy; bone remodelling/drug effects; kidney transplantation; renal osteodystrophy/pathology