title: A narrow-band ultraviolet B course improves vitamin D balance and alters cutaneous CYP27A1 and CYP27B1 mRNA expression levels in haemodialysis patients supplemented with oral vitamin D.
abstract: OBJECTIVE
  Chronic kidney disease (CKD) patients on dialysis are prone to vitamin D insufficiency despite oral vitamin D supplementation. Here, we studied whether narrow-band ultraviolet B (NB-UVB) exposures improve vitamin D balance.
  
  
  METHODS
  14 haemodialysis patients and 15 healthy subjects receiving oral cholecalciferol 20 µg daily got nine NB-UVB exposures on the entire body. Serum 25-hydroxyvitamin D (25(OH)D) was measured by radioimmunoassay. Cutaneous mRNA expression levels of CYP27A1 and CYP27B1, two enzymes required for hydroxylation of vitamin D into its active metabolite, were also measured.
  
  
  RESULTS
  The baseline serum 25(OH)D concentration was 57.6 ± 18.2 nmol/l in the CKD patients and 74.3 ± 14.8 nmol/l in the healthy subjects. The NB-UVB course increased serum 25(OH)D by 14.0 nmol/l (95% CI 8.7-19.5) and 17.0 nmol/l (CI 13.7-20.2), respectively. At baseline the CKD patients showed significantly increased CYP27B1 levels compared to the healthy subjects.
  
  
  CONCLUSIONS
  A short NB-UVB course is an efficient way to improve vitamin D balance in CKD patients on dialysis who are receiving oral vitamin D supplementation. The increased cutaneous CYP27B1 levels in the CKD patients suggest that the loss of renal activity of this enzyme is at least partially compensated for by the skin.
authors.affiliation: Department of Dermatology, Tampere University Hospital, Tampere, Finland.
authors.forename: Meri J
authors.initials: MJ
authors.lastname: Ala-Houhala
authors.forename: Katja
authors.initials: K
authors.lastname: Vähävihu
authors.forename: Erna
authors.initials: E
authors.lastname: Snellman
authors.forename: Taina
authors.initials: T
authors.lastname: Hasan
authors.forename: Hannu
authors.initials: H
authors.lastname: Kautiainen
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*; D000284:Administration, Oral; D000293:Adolescent; D000368:Aged; D053493:Cholestanetriol 26-Monooxygenase / Q000235:genetics / Q000378:metabolism*; D003131:Combined Modality Therapy / Q000379:methods; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D006435:Renal Dialysis / Q000009:adverse effects; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000378:metabolism* / Q000628:therapy*; D012867:Skin / Q000378:metabolism* / Q000528:radiation effects; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism; D016896:Treatment Outcome; D014467:Ultraviolet Therapy / Q000379:methods; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood; D014808:Vitamin D Deficiency / Q000209:etiology / Q000378:metabolism / Q000628:therapy*; D055815:Young Adult
chemical_list: D012333:RNA, Messenger; D014807:Vitamin D; D013250:Steroid Hydroxylases; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase