Vitamin D and Cathelicidin (LL-37) Status in Patients with Type 2 Diabetes and Staphylococcus aureus Nasal Carriage

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The Review of Diabetic Studies,2021,17,1,30-37.
Published:July 2021
Type:Original Article
Author(s) affiliations:

Marina N. Plataki1,2, Rodanthi Vamvoukaki2, George Samonis2, Charalampos Bikis2, Maria Gorgomiti3, John A. Papadakis2, Sofia Maraki3, and Diamantis P. Kofteridis1,2

1Laboratory of Internal Medicine, Host Defense Unit, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece

2Department of Internal Medicine and Infectious Diseases, University Hospital of Heraklion, Heraklion, Crete, Greece

3Department of Clinical Microbiology, University Hospital of Heraklion, Heraklion, Crete, Greece


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.