title: Elevated cardiac markers in chronic kidney disease as a consequence of hyperphosphatemia-induced cardiac myocyte injury.
abstract: BACKGROUND
  Elevated cardiac markers (CMs) and hyperphosphatemia are commonly encountered in patients with chronic kidney diseases (CKD), but the causal relationship between them has not been established.
  
  
  METHODS
  We enrolled 151 patients with different kidney functions in a cross-sectional study to explore the relationship of serum phosphorus with CMs, including cardiac troponin T (cTnT), myoglobin (MYO), creatine kinase-MB (CK-MB), and brain natriuretic peptide (BNP). Then, the effect of reducing phosphorus levels on CMs by taking phosphate binder for 3 months was prospectively observed in 64 hemodialysis patients. Finally, human cardiomyocytes were exposed to different concentrations of inorganic phosphorus to examine its underlying mechanism.
  
  
  RESULTS
  1) Serum phosphorus and CMs gradually increased as the glomerular filtration rate declined in CKD patients (p<0.01). 2) Elevation of CMs was much greater and cardiac structure and function were worse in CKD patients who had higher serum phosphorus concentrations (p<0.05). 3) Serum phosphorus level positively correlated with cTnT, MYO, and BNP in CKD patients (p<0.001). 4) In hemodialysis patients, the reduction of cTnT, MYO, and CK-MB was synchronous with the pharmacologically-induced decline of serum phosphorus level. However, levels of serum Fibroblast growth factor 23 (FGF23) had no statistical decrease. 5) Simulated hyperphosphatemia inhibited proliferation of human cardiomyocytes in a time- and concentration-dependent manner.
  
  
  CONCLUSIONS
  Hyperphosphatemia may induce myocardial damage in CKD patients, possibly through triggering apoptosis of human cardiomyocytes, and this could account for the elevated cardiac markers in CKD patients.
authors.affiliation: Department of Nephrology and Rheumatology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China (mainland).
authors.forename: Shu
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Nephrology and Rheumatology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China (mainland).
authors.forename: Ling
authors.initials: L
authors.lastname: Qin
authors.affiliation: Department of Biomedical Engineering, University of Huston, Huston, USA.
authors.forename: Tianfu
authors.initials: T
authors.lastname: Wu
authors.affiliation: Department of Nephrology and Rheumatology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China (mainland).
authors.forename: Bingqing
authors.initials: B
authors.lastname: Deng
authors.affiliation: Department of Nephrology and Rheumatology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China (mainland).
authors.forename: Yuerun
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Nephrology and Rheumatology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China (mainland).
authors.forename: Dayong
authors.initials: D
authors.lastname: Hu
authors.affiliation: Department of Biomedical Engineering, University of Houston, Huston, USA.
authors.forename: Chandra
authors.initials: C
authors.lastname: Mohan
authors.affiliation: Renal Path Diagnostics, Pathologists BioMedical Laboratories and Department of Pathology, Baylor University Medical Center, Dallas, USA.
authors.forename: Xin J
authors.initials: XJ
authors.lastname: Zhou
authors.affiliation: Department of Nephrology and Rheumatology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China (mainland).
authors.forename: Ai
authors.initials: A
authors.lastname: Peng
mesh_terms: D015415:Biomarkers / Q000378:metabolism*; D000089703:Fibroblast Growth Factor-23; D005919:Glomerular Filtration Rate; D006331:Heart Diseases / Q000150:complications / Q000378:metabolism*; D006801:Humans; D054559:Hyperphosphatemia / Q000150:complications / Q000378:metabolism*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000473:pathology*
chemical_list: D015415:Biomarkers; C000717427:FGF23 protein, human; D000089703:Fibroblast Growth Factor-23