Epidemiological studies show a strong correlation between vitamin D deficiency and asthma severity. Genetic studies have identified vitamin D receptor polymorphisms as a risk factor for asthma in diverse human populations. Calcitriol (1,25-dihydroxyvitamin D3), the physiologically active metabolite of mammalian vitamin D, is able to modulate receptor and cytokine expression as well as cell differentiation and maturation of various leukocytes in an anti-inflammatory manner. Despite the role of eosinophils in allergic asthma pathology, little is known about the effects of calcitriol on eosinophil biology. Calcitriol has a direct modulatory effect on eosinophil survival and effector functions in vitro.
Methods
Human peripheral blood eosinophils from atopic donors were isolated and incubated with calcitriol (VD) and interleukin-5 (IL-5). Dose-response assays tested physiological doses of calcitriol (0.01-100 nM). The potentiating effect of calcitriol (10 nM) on eosinophil survival with IL-5 (1 ng/mL) was investigated on a 14-day time course. Viability/apoptosis/necrosis levels were obtained using an Annexin-V/PI flow cytometry assay. Eosinophil crystalloid granules and EPX release were measured by CD63 and EPX monoclonal antibody staining using flow cytometry. EPX activity was determined using an OPD substrate colorimetric assay.
Anzeige
Results
Eosinophil survival increased after 24 h of calcitriol treatment in a dose-dependent manner (Fig1. n = 5). Calcitriol alone yielded similar eosinophil survival rates (Fig2.4.5 ± 1.5%, n = 11) after 7 days compared to control media (Fig2. 2.1 ± 2.1%, n = 11). In contrast, calcitriol potentiated the survival effect of IL-5 starting from day 7. At 14 days, 66 ± 7% of eosinophils were still intact when treated with calcitriol and IL-5, compared to IL-5 alone (Fig2. 34 ± 8%, p < 0.05, n = 4). Cells treated with IL-5 alone showed increased necrosis from day 7 onward with 32% additional necrotic eosinophils at day 14, compared to the combined treatment. As cell debris increased in correlation with necrosis (Fig3 A&B.), low-SSC/FSC events stained positive for CD63 and EPX confirming whole, intact crystalloid granules along with free EPX in media (Fig4.). Moreover, EPX activity in media was reduced on days 4 and 7 following calcitriol and IL-5 treatment (Fig5.). Overall, reduced spontaneous EPX release strongly correlated with increased eosinophil survival (Fig6. r2 = 0.96, n = 4-11).
×
×
×
×
×
×
Conclusions
These findings support the hypothesis that calcitriol plays an anti-inflammatory role by decreasing cytotoxic granule release into airway mucosal tissues during allergic inflammatory responses, therefore reducing mucosal inflammation and tissue damage.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Wer sich an einem Essensrest verschluckt und um Luft ringt, benötigt vor allem rasche Hilfe. Dass Umstehende nur in jedem zweiten Erstickungsnotfall bereit waren, diese zu leisten, ist das ernüchternde Ergebnis einer Beobachtungsstudie aus Japan. Doch es gibt auch eine gute Nachricht.
In einer Leseranfrage in der Zeitschrift Journal of the American Academy of Dermatology möchte ein anonymer Dermatologe bzw. eine anonyme Dermatologin wissen, ob er oder sie einen Patienten behandeln muss, der eine rassistische Tätowierung trägt.
Extreme Arbeitsverdichtung und kaum Supervision: Dr. Andrea Martini, Sprecherin des Bündnisses Junge Ärztinnen und Ärzte (BJÄ) über den Frust des ärztlichen Nachwuchses und die Vorteile des Rucksack-Modells.
In einer Metaanalyse von 18 Studien war die Rate von Nachblutungen nach einer Abszesstonsillektomie mit weniger als 7% recht niedrig. Nur rund 2% der Behandelten mussten nachoperiert werden. Die Therapie scheint damit recht sicher zu sein.
Update HNO
Bestellen Sie unseren Fach-Newsletter und bleiben Sie gut informiert – ganz bequem per eMail.