title: Bone resorption is increased in pheochromocytoma patients and normalizes following adrenalectomy.
abstract: BACKGROUND
  The sympathetic nervous system (SNS) controls bone turnover in rodents, but it is uncertain whether a similar role for the SNS exists in humans. Pheochromocytomas are catecholamine-producing neuroendocrine tumors. Because catecholamines are the neurotransmitters of the SNS, we hypothesized that pheochromocytoma patients have increased bone turnover.
  
  
  OBJECTIVE
  Our objective was to compare bone turnover in pheochromocytoma patients and controls.
  
  
  METHODS
  This retrospective case-control study was performed at the Endocrine Department of the Academic Medical Center of the University of Amsterdam in The Netherlands from 2007 until 2011.
  
  
  METHODS
  All patients were screened for pheochromocytoma. Cases (n = 21) were identified by 24-h urinary excretion of fractionated metanephrines above the institutional reference value and confirmed by histology after adrenalectomy. All patients screened and diagnosed as not having pheochromocytoma served as controls (n = 126).
  
  
  METHODS
  The difference in bone turnover markers C-terminal cross-linking telopeptides of collagen type I (CTx) and procollagen type 1 N propeptide (P1NP) between cases and controls was the main outcome measure.
  
  
  RESULTS
  CTx concentrations were higher in cases [343 ng/liter; interquartile range (IQR), 295 ng/liter] than in controls (232 ng/liter; IQR, 168 ng/liter; P < 0.001) and decreased after adrenalectomy [before, 365 ng/liter (IQR, 450 ng/liter); after, 290 ng/liter (IQR, 241 ng/liter); P = 0.044]. The effect remained after adjustment for possible confounders. P1NP concentrations did not differ.
  
  
  CONCLUSIONS
  This study shows that pheochromocytoma patients have increased bone resorption, which normalizes after adrenalectomy. This finding supports the concept of regulation of bone remodeling by the SNS in humans.
authors.affiliation: Academic Medical Center, University of Amsterdam, P.O. Box 22660, 1100 DD Amsterdam, The Netherlands.
authors.forename: A G
authors.initials: AG
authors.lastname: Veldhuis-Vlug
authors.forename: M
authors.initials: M
authors.lastname: El Mahdiui
authors.forename: E
authors.initials: E
authors.lastname: Endert
authors.forename: A C
authors.initials: AC
authors.lastname: Heijboer
authors.forename: E
authors.initials: E
authors.lastname: Fliers
authors.forename: P H
authors.initials: PH
authors.lastname: Bisschop
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000503:physiopathology* / Q000601:surgery; D000315:Adrenalectomy; D000328:Adult; D000368:Aged; D001862:Bone Resorption / Q000503:physiopathology* / Q000601:surgery; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000503:physiopathology* / Q000601:surgery; D012189:Retrospective Studies; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D016896:Treatment Outcome