Impact of vitamin D supplementation on markers of inflammation in adults with cystic fibrosis hospitalized for a pulmonary exacerbation

Patients with cystic fibrosis (CF) suffer from chronic lung infection and inflammation leading to respiratory failure. Vitamin D deficiency is common in patients with CF, and correction of vitamin D deficiency may improve innate immunity and reduce inflammation in patients with CF. We conducted a double-blinded, placebo-controlled, randomized clinical trial of high-dose vitamin D to assess the impact of vitamin D therapy on antimicrobial peptide concentrations and markers of inflammation. We randomized 30 adults with CF hospitalized with a pulmonary exacerbation to 250,000 IU of cholecalciferol or placebo, and evaluated changes in plasma concentrations of inflammatory markers and the antimicrobial peptide LL-37 at baseline and 12 weeks post intervention. In the vitamin D group, there was a 50.4% reduction in tumor necrosis factor-α (TNF-α) at 12 weeks (P<0.01), and there was a trend for a 64.5% reduction in interleukin-6 (IL-6) (P=0.09). There were no significant changes in IL-1β, IL-8, IL-10, IL-18BP and NGAL (neutrophil gelatinase-associated lipocalin). We conclude that a large bolus dose of vitamin D is associated with reductions in two inflammatory cytokines, IL-6 and TNF-α. This study supports the concept that vitamin D may help regulate inflammation in CF, and that further research is needed to elucidate the potential mechanisms involved and the impact on clinical outcomes.

Lipopolysaccharide (LPS) from Burkholderia cepacia is more active than LPS from Pseudomonas aeruginosa and Stenotrophomonas maltophilia in stimulating tumor necrosis factor alpha from human monocytes

Whole cells and lipopolysaccharides (LPSs) extracted from Burkholderia cepacia, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Escherichia coli were compared in their ability to stimulate tumor necrosis factor alpha (TNF-alpha) from the human monocyte cell line MonoMac-6. B. cepacia LPS, on a weight-for-weight basis, was found to have TNF-alpha-inducing activity similar to that of LPS from E. coli, which was approximately four- and eightfold greater than the activity of LPSs from P. aeruginosa and S. maltophilia, respectively. The LPS-stimulated TNF-alpha production from monocytes was found to be CD14 dependent. These results suggest that B. cepacia LPS might play a role in the pathogenesis of inflammatory lung disease in cystic fibrosis, and in some patients it might be responsible, at least in part, for the sepsis-like cepacia syndrome.

A melanin pigment purified from an epidemic strain of Burkholderia cepacia attenuates monocyte respiratory burst activity by scavenging superoxide anion

The acquisition of Burkholderia cepacia in some cystic fibrosis patients is associated with symptoms of acute pulmonary inflammation that may be life threatening. The ability of lipopolysaccharide (LPS) from B. cepacia to prime a monocyte cell line for enhanced superoxide anion generation was investigated and compared with the priming activities of LPSs from Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Escherichia coli. The human monocyte cell line MonoMac-6 (MM6) was primed overnight with different LPSs (100 ng/ml), and the respiratory burst was triggered by exposure to opsonized zymosan (125 micrograms/ml). Superoxide generation was detected by enhanced chemiluminescence with Lucigenin. B. cepacia LPS was found to prime MM6 cells to produce more superoxide anion than P. aeruginosa or S. maltophilia LPS, and this priming response was CD14 dependent. In addition, the inhibition of respiratory burst responses in monocytes by a bacterial melanin-like pigment purified from an epidemic B. cepacia strain was investigated. The melanin-like pigment was isolated from tyrosine-enriched media on which B. cepacia had been grown and was purified by gel filtration, anion ion-exchange chromatography, and ethanol precipitation. The scavenging potential of the melanin-like pigment for superoxide anion radical (*O2-) generated during the respiratory burst was confirmed with superoxide produced from a cell-free system with xanthine-xanthine oxidase and detected by electron paramagnetic resonance spectroscopy with the spin trap 5-diethoxyphosphoryl-5-methyl-1-pyrroline-n-oxide. The addition of melanin during the LPS priming stage had no effect on the subsequent triggering of the respiratory burst, but melanin inhibited *O2- detection when added at the triggering stage of the respiratory burst. We conclude that melanin-producing B. cepacia may derive protection from the free-radical-scavenging properties of this pigment.