ABSTRACT
OBJECTIVE: Type 2 diabetes mellitus (T2D) is characterized by the dysregulation of innate immunity leading to higher rates of Staphylococcus aureus nasal carriage, an important risk factor for severe infections. 25-hydroxy vitamin D (25(OH)D) may contribute, via the production of the antimicrobial peptide cathelicidin (LL-37), to epithelial host defense against S. aureus. This study evaluated whether 25(OH)D and LL-37 levels determine S. aureus nasal carriage. METHODS: Two consecutive nasal swabs were obtained from 118 T2D patients to determine S. aureus nasal carriage status. Serum levels of 25(OH)D and LL-37 were measured using chemiluminescence immunoassay and enzyme-linked immunosorbent assay, respectively. Supplementation of vitamin D by a number of participants was taken into account and evaluated. RESULTS: Forty-two T2D patients (35.6%) were found to be colonized by S. aureus. Vitamin D deficiency was detected in sixty-nine patients (65.7%). Median value for LL-37 in T2D patients was 0.89 ng/ml (range 0.05-8.62 ng/ml). Circulating levels of LL-37 were higher in nasal carriers compared to non-carriers (1.25 ng/ml vs 0.72 ng/ml; p < 0.001). No difference was found in serum 25(OH)D levels between carriers and non-carriers. 25(OH)D and LL-37 serum levels correlated positively in non-carriers, while the relationship was inversed in the carrier group. Vitamin D supplementation was not associated with lower incidence of S. aureus nasal carriage (p = 0.706). CONCLUSIONS: T2D patients presented decreased serum levels of 25(OH)D and LL-37, indicating a potential impairment of innate immunity. Expression of LL-37 may be induced by S. aureus nasal carriage among people with diabetes. Vitamin D supplementation did not influence S. aureus nasal colonization in T2D patients.
Subject(s)
Diabetes Mellitus, Type 2 , Staphylococcus aureus , Antimicrobial Cationic Peptides , Antimicrobial Peptides , Carrier State , Humans , Vitamin D , CathelicidinsABSTRACT
BACKGROUND: Interleukin 6 (IL-6), a proinflammatory cytokine, is elevated in patients with type 2 diabetes (T2D), and is considered an independent predictor of T2D. IL-6 single-nucleotide polymorphisms (SNPs) have been associated with higher levels of IL-6. This study investigated the role of an IL-6 gene polymorphism and its possible association to T2D in the genetically homogeneous Greek population of the island of Crete. MATERIALS AND METHODS: A total of 144 patients with T2D and 180 controls, all Cretans, selected from the Diabetes Clinic and the Department of Internal Medicine at the University Hospital of Heraklion, Crete, Greece, were genotyped for the IL-6 -174G>C (rs1800795) SNP by the restriction fragment length polymorphism method. RESULTS: The G/C genotype and the minor allele C of the IL-6 rs1800795 SNP were more common in individuals with T2D than controls (p = 0.004, odds ratio [OR] = 1.98, 95% confidence interval [CI]: 1.24-3.18 and p = 0.011, OR = 1.59, 95% CI: 1.11-2.26, respectively). CONCLUSION: An association of the rs1800795 SNP of the IL-6 gene with T2D has been detected for the first time in Cretans. The present results, in combination with those presented previously from different ethnic/racial populations, highlight the necessity of comparative studies among different ethnic/racial populations to detect genetic characteristics and associations with T2D.
