title: Calcium supplementation attenuates citrate-related changes in bone metabolism: a placebo-controlled crossover study in healthy volunteers.
abstract: BACKGROUND
  Citrate is the anticoagulation of choice in apheresis procedures. Citrate anticoagulation results in a short-term increase in serological markers of bone turnover, with uncertain clinical significance.
  
  
  OBJECTIVE
  To understand the effect of calcium supplementation on serological bone turnover markers during an acute citrate load as a mimic of citrate anticoagulation during apheresis procedures.
  
  
  METHODS
  A placebo-controlled, crossover study was conducted in 22 healthy volunteers. Volunteers received a standardized citrate load at a fixed dose of 1.5 mg/kg of body weight/min for 80 min for three times and a single placebo infusion as a control. Each intervention was separated by a wash-out interval of 2 to 3 weeks. During two citrate infusions, volunteers received an additional calcium supplementation, consisting of either oral administration of calcium carbonate or an i.v. bypass infusion of calcium gluconate. Serial blood samples were collected for the determination of ionized calcium (iCa), intact parathyroid hormone (iPTH) and markers of bone remodeling, C-telopeptide of type 1 collagen (CTX) and osteocalcin (OC).
  
  
  RESULTS
  The infusion of citrate without calcium supplementation resulted in an increase in the bone formation marker OC and the bone resorption marker CTX, in addition to the changes in iPTH and iCa. The administration of calcium by either oral administration or as an i.v. bypass infusion attenuated the observed changes in CTX, but showed no effects on the elevation of the bone formation marker OC. There was no difference in the attenuation of CTX between the two calcium formulations. However, the i.v. application of calcium gluconate had a superior effect in reducing the change of serum iPTH and iCa as compared to the oral administration of calcium carbonate.
  
  
  CONCLUSIONS
  Calcium supplementation is an effective method in damping the citrate-related transient increase of the serological bone resorption marker CTX. As a mimic for the citrate-based apheresis procedure, our data may enforce the prophylactic application of calcium supplementation to attenuate the short-term elevation of bone resorption related to an acute citrate load.
authors.affiliation: Fujian Blood Center, Fuzhou 350004, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Jianming
authors.initials: J
authors.lastname: Hou
authors.forename: Guolong
authors.initials: G
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Lin
authors.forename: Hongkeng
authors.initials: H
authors.lastname: Lin
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Chu
authors.forename: Jia
authors.initials: J
authors.lastname: Zeng
authors.forename: Cen
authors.initials: C
authors.lastname: Chen
authors.forename: Juan
authors.initials: J
authors.lastname: Lin
authors.forename: Markus
authors.initials: M
authors.lastname: Dettke
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001781:Blood Component Removal / Q000009:adverse effects; D016723:Bone Remodeling / Q000187:drug effects / Q000502:physiology; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000097:blood / Q000652:urine; D002119:Calcium Carbonate / Q000008:administration & dosage / Q000494:pharmacology*; D002125:Calcium Gluconate / Q000008:administration & dosage / Q000494:pharmacology*; D019343:Citric Acid / Q000009:adverse effects / Q000494:pharmacology*; D024042:Collagen Type I / Q000097:blood; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D010455:Peptides / Q000097:blood; D010919:Placebos
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010455:Peptides; D010919:Placebos; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D019343:Citric Acid; D002119:Calcium Carbonate; D002125:Calcium Gluconate; D002118:Calcium