There are several potential mechanisms that have been described both in vitro models and in vivo models in which has been linked to asthma control with elevated levels of vitamin D in serum. These mechanisms include structural effects in the lungs, immunomodulation, modulation of smooth muscle response to level and effect on bronchial response to inhaled medicines to treat asthma.
* Structural mechanisms Studies were conducted in rats of 50 days old, lung compliance was measured and decreased it in rats whose mothers had a diet of deprivation of vitamin D compared to those rats whose mothers received vitamin supplementation was observed. In human groups, pulmonary function tests at age 6 were carried out, and there was a significant difference between children with mothers with vitamin D deficiency during pregnancy and children whose mothers had normal levels during pregnancy. These findings suggest that there is a strong relationship between lung embryonic development serum level of vitamin D and therefore this plays a key role in the structural development of the airways
* Anti-inflammatory Mechanisms Within these mechanisms, they are significantly inhibiting pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor alpha (TNF-A) by way of inhibition of MAP 38 produced by monocytes. Another such mechanism is the inhibition of transcription factor (necrosis factor kappa-beta). We observed a decrease in the phosphorylation and production of reactive oxygen species with the addition of 1-25 dihydroxyvitamin D levels which leads to less inflammatory damage in the respiratory epithelium.
* Immunomodulation Effects occur in both innate immunity and adaptive, innate immunity in the effect of 1,25 hydroxyvitamin D has an effect on the reduction of inflammatory cytokines and in the decreased expression of Toll-like receptors monocytes. Also active antimicrobial peptides such as defensin 2 and 4 and the human defensin cathecidina 18, studies where low levels of vitamin D are associated and low levels of this peptide
* Effects on helper T lymphocytes Molecular effects, vitamin D levels are associated with decreased circulating IgE as well as decreasing the TH1 response and therefore TH2, however the role of vitamin D on these cells is unclear, and some studies have shown the prevalence of TH2 response in patients with adequate levels of Vitamin D, however the decrease in the inflammatory response and the production of cytokines such as IL 12 has shown that vitamin D it modulates the response that causes pathogenesis Asthma
* Decrease in early infections or severity The previously mentioned effects on adaptive and innate immunity may decrease the risk of early respiratory tract infections, which have been associated in the first years of life with a high incidence of wheezing. In Hawaiian children under age 5 suffering from rickets incidence of respiratory tract diseases and wheezing it was higher than that of the population without vitamin D deficiency
