title: B-type (brain) natriuretic peptide and pruritus in hemodialysis patients.
abstract: OBJECTIVE
  While pruritus is a common complication in hemodialysis patients, the pathophysiological mechanisms remain obscure. Recently, B-type (brain) natriuretic peptide (BNP) has been defined as an itch-selective neuropeptide in pruriceptive neurons in mice, and higher serum levels of BNP are frequently observed in hemodialysis patients. The objective of the present study was to evaluate the role of serum BNP in pruritus in patients undergoing hemodialysis.
  
  
  METHODS
  The current cross-sectional study was performed on 43 patients undergoing maintenance hemodialysis. A visual analog scale (VAS) measuring the general severity of pruritus (values from 0 to 10, with higher values indicating more severe pruritus) in daytime and at night was self-reported by patients. Each patient's background and laboratory tests, including serum BNP in the post-hemodialysis period, were collected. The correlation between VAS and clinical parameters was evaluated.
  
  
  RESULTS
  Both daytime and nighttime VAS scores in diabetic patients were significantly less than those in nondiabetic patients. Multiple regression analysis revealed that pruritus in daytime was worsened by serum BNP (β=2.0, t=2.4, P=0.03), calcium (β=4.4, t=5.2, P<0.0001), and β2-microglobulin (β=2.0, t=3.0, P=0.007), while it was eased by age (β=-2.2, t=-3.2, P=0.0004). Nocturnal pruritus was severe in nondiabetic patients (β=1.7, t=3.8, P=0.0005) and weakened by the total iron binding capacity (β=-2.9, t=-3.1, P=0.004).
  
  
  CONCLUSIONS
  It is suggested that a higher level of serum BNP increases the pruritus of hemodialysis patients in daytime and that diabetic patients are less sensitive to itch, especially at nighttime.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Ayano
authors.initials: A
authors.lastname: Sonoda
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Nogi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ogushi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Reo
authors.initials: R
authors.lastname: Kanda
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Nao
authors.initials: N
authors.lastname: Nohara
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Aoki
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Nakata
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Io
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kurusu
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Hamada
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Horikoshi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tomino
keywords: B-type brain natriuretic peptide; cerebrospinal fluid; hemodialysis; itch-selective neuropeptide; pruriceptive neurons; pruritus; visual analog scale