title: Narrow-band ultraviolet B exposure increases serum vitamin D levels in haemodialysis patients.
abstract: BACKGROUND
  Chronic kidney disease (CKD) patients are especially prone to vitamin D insufficiency. Narrow-band ultraviolet B (NB-UVB) treatment increases serum 25-hydroxyvitamin D [25(OH)D] in dermatological patients, and we studied whether it also improves vitamin D balance in CKD patients on haemodialysis.
  
  
  METHODS
  Fifteen dialysis patients (mean age 48.3 years) and 12 healthy subjects (mean age 43.6 years) received nine NB-UVB exposures on the upper body. Serum 25(OH)D and 1,25(OH)(2)D were measured before and after the exposures. From skin biopsy specimen messenger RNA (mRNA) expression levels of CYP24A1 and CYP27B1, two enzymes needed for hydroxylation of vitamin D into its active metabolites, and of antimicrobial peptide cathelicidin, were examined.
  
  
  RESULTS
  Before NB-UVB, mean serum 25(OH)D was 32.5 ± 10.2 nmol/L in the dialysis patients and 60.2 ± 18.0 nmol/L in the healthy subjects (P < 0.001). After eight NB-UVB exposures, serum 25(OH)D increased by 13.8 nmol/L (43%; P < 0.001) and serum 1,25(OH)(2)D by 3.3 pmol/L (27%; P = 0.002) in the dialysis patients. After NB-UVB exposures, CYP27B1 mRNA was increased (P = 0.04), whereas cathelicidin mRNA was decreased (P < 0.0001) compared to non-treated healthy subjects. One and 2 months after NB-UVB exposure, serum 25(OH)D was still 10% higher than initially in the dialysis patients.
  
  
  CONCLUSIONS
  The present study shows that a short course of NB-UVB exposure increases significantly serum 25(OH)D and 1,25(OH)(2)D in dialysis patients. The effect is, however, short lasting suggesting that the patients need cyclic NB-UVB exposure to maintain their improved vitamin D concentration.
authors.affiliation: Department of Dermatology, Tampere University Hospital, Tampere, Finland. meri.ala-houhala@pshp.fi
authors.forename: Meri J
authors.initials: MJ
authors.lastname: Ala-Houhala
authors.forename: Katja
authors.initials: K
authors.lastname: Vähävihu
authors.forename: Taina
authors.initials: T
authors.lastname: Hasan
authors.forename: Hannu
authors.initials: H
authors.lastname: Kautiainen
authors.forename: Erna
authors.initials: E
authors.lastname: Snellman
authors.forename: Piia
authors.initials: P
authors.lastname: Karisola
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Dombrowski
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schauber
authors.forename: Heikki
authors.initials: H
authors.lastname: Saha
authors.forename: Timo
authors.initials: T
authors.lastname: Reunala
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D006435:Renal Dialysis / Q000009:adverse effects*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000528:radiation effects*; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays; D014467:Ultraviolet Therapy; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D065668:Vitamin D3 24-Hydroxylase; D055815:Young Adult; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D012333:RNA, Messenger; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D013250:Steroid Hydroxylases; C585549:CYP24A1 protein, human; D065668:Vitamin D3 24-Hydroxylase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D054804:Cathelicidins