High levels of serum vitamin D-binding protein in patients with psoriasis: A case-control study and effects of ultraviolet B phototherapy

Amra Osmancevic,Maria Siekkeri Vandikas,Martin Gillstedt,Kerstin Landin-Wilhelmsen,Agneta Holmäng

doi:10.1016/j.jsbmb.2021.105895

Amra Osmancevic, Maria Siekkeri Vandikas + Show 3 more

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https://doi.org/10.1016/j.jsbmb.2021.105895

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Abstract

The role of vitamin D in psoriasis remains contradictory despite the fact that vitamin D analogues constitute an established treatment for psoriasis. It has been proposed that the ability of vitamin D to exert anti-inflammatory effects might not depend solely on the concentration of serum 25(OH)D but also on the concentration of vitamin D-binding protein (DBP). High concentrations of DBP might diminish vitamin D’s biologic action. The aims of this study were (i) to analyze the serum levels of DBP, total and calculated free 25(OH)D in patients with psoriasis and compare the results with healthy controls and (ii) to study the effect of ultraviolet B (UVB) phototherapy on DBP levels. Caucasian subjects (n = 68) with active plaque psoriasis were compared with a population-based sample of men and women (n = 105), matched for age and sex. Season of enrollment was taken into consideration. The patients were also studied before and after UVB phototherapy. The severity of the disease was calculated as Psoriasis Area Severity Index (PASI). DBP, free 25(OH)D index and total 25(OH)D were higher in patients with psoriasis compared with controls (P= 0.004, P = 0.045 and P < 0.0001, respectively). DBP did not change after phototherapy, whereas 25(OH)D increased and intact parathyroid hormone (iPTH) decreased (P < 0.001 for both). Psoriasis improved and PASI decreased after phototherapy (P < 0.001). There was no correlation between DBP and 25(OH)D or between DBP and PASI. Measurement of DBP is recommended when evaluating vitamin D status in patients with psoriasis. High DBP levels in psoriasis imply a disturbed vitamin D pathway that warrants further investigation. Direct measurement of free 25(OH)D, instead of total 25(OH)D that circumvents abnormally high levels of DBP, could be considered.

Highlights

IntroductionINTRODUCTION 1.1 VITAMIN DVitamin D is a fat-soluble secosteroid. Already in the 1800s the supplementation of children with cod liver oil was practiced in industrialized countries in order to avoid rickets in children [1]
Vitamin D3 could not be distinguished from 7-DHC but could be distinguished from cholesterol, which is the precursor of 7-DHC. 1,25(OH)2D3 could not be distinguished from its major catabolite, 1,24,25(OH)3D3, (Figure 8)
The highest amount of vitamin D metabolites was noted in perilesional skin after Narrow band UVB (NBUVB) phototherapy

Summary

Introduction

INTRODUCTION 1.1 VITAMIN DVitamin D is a fat-soluble secosteroid. Already in the 1800s the supplementation of children with cod liver oil was practiced in industrialized countries in order to avoid rickets in children [1]. In 1822, the association of lack to sun exposure and rickets was discovered by Sniadecki It was not until the beginning of the 20th century that McCollum discovered that the anti-rachitic effect of cod liver oil was due to a substance that was different from vitamin A, and this substance was given the name vitamin D since the letters A, B and C were already taken [2, 3]. To compare the serum levels of DBP in psoriasis with population-based controls (Paper II) and to study the effect of phototherapy (Paper II) and etanercept (Paper III) on vitamin D status and DBP levels. DBP serum levels were higher in patients with psoriasis compared to population-based controls.

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