RESUMO
BACKGROUND: Vitamin D deficiency is a major global health problem. Most previous studies focused attention on the significant role of sunlight exposure in the homeostasis of vitamin D and calcium blood levels. Magnesium is pivotal in the proper functioning of vitamin D, and the physiologic functions of different organs require a balanced vitamin D and magnesium status. The relationship between sunlight exposure and blood levels of vitamin D and magnesium has often been overlooked. The aim of this study was to evaluate vitamin D and magnesium status based on sunlight exposure and ethnicity in Bahraini and expatriate workers. METHODS: A cross-sectional study was conducted between October 2018 and September 2019. One hundred and seventy-four subjects participated in this study were subdivided based on their ethnicity and work environment-dependent exposure to sunlight into four groups: (1) Bahraini exposed (n=94), (2) Bahraini non-exposed (n=25), (3) expatriate exposed (n=31), and (4) expatriate non-exposed (n=24). Blood levels of vitamin D and magnesium were evaluated for all the participants. RESULTS: Independent of ethnicity, vitamin D levels were insignificantly different among the studied groups and were all below the normal reference range. Yet, there was still a sunlight-dependent increase in vitamin D level that could be seen only in Bahraini workers. Magnesium levels were significantly higher in expatriates when compared to Bahraini workers. Sunlight-exposed expatriates had significantly higher magnesium levels than their Bahraini counterparts, while there was no significant difference between both ethnicities in the non-exposed groups. CONCLUSION: Country- and ethnic-specific definitions for vitamin D status and sunlight exposure are recommended. The assessment of magnesium status is pivotal in the overall assessment of vitamin D status.
RESUMO
The Immune System-Released Activating Agent (ISRAA) was discovered as a novel molecule that functions as a mediator between the nervous and immune systems in response to a nervous stimulus following an immune challenge. This research investigated the role of ISRAA) in promoting the ontogeny of the mouse brain astrocytes. Astrocyte cultures were prepared from two-month-old BALB/c mice. Recombinant ISRAA protein was used to stimulate astrocyte cultures. Immunohistochemistry and ELISA were utilized to measure ISRAA and IFN-γ levels, IFN-γR expression and STAT1 nuclear translocation. MTT-assay was used to evaluate cellular survival and proliferation. To assess astrocyte cell lysates and tyrosine-phosphorylated proteins, SDS-PAGE and western blot were used. ISRAA was highly expressed in mouse embryonic astrocytes, depending on cell age. Astrocytes aged seven days (E7) showed increased proliferation and diminished differentiation, while 21-day-old (E21) astrocytes depicted reversed effects. IFN-γ was involved in the ISRAA action as ISRAA induced IFN-γ in both age groups, but only E21 astrocytes expressed IFN-γR. ISRAA stimulation of E21 resulted in tyrosine phosphorylation of numerous cellular proteins and the nuclear translocation of STAT1, a signalling pathway utilized by IFN-γ. The results suggest that ISRAA is involved in mouse brain development through the cytokine network involving IFN-γ.