Local Sustained Delivery of 25-Hydroxyvitamin D3 for Production of Antimicrobial Peptides

Abstract

Purpose-This study seeks to develop fiber membranes for local sustained delivery of 25-hydroxyvitamin D 3 to induce the expression and secretion of LL-37 at or near the surgical site, which provides a novel therapeutic approach to minimize the risk of infections.Methods-25-hydroxyvitamin D 3 loaded poly( L -lactide) (PLA) and poly(ε-caprolactone) (PCL) fibers were produced by electrospinning. The morphology of obtained fibers was characterized using atomic force microscope (AFM) and scanning electron microscope (SEM). 25-hydroxyvitamin D 3 releasing kinetics were quantified by enzyme-linked immunosorbent assay (ELISA) kit. The expression of cathelicidin (hCAP 18) and LL-37 was analyzed by immunofluorescence staining and ELISA kit. The antibacterial activity test was conducted by incubating pseudomonas aeruginosa in a monocytes' lysis solution.Results-AFM images suggest that the surface of PCL fibers is smooth, however, the surface of PLA fibers is relatively rough, in particular, after encapsulation of 25-hydroxyvitamin D 3 . The duration of 25-hydroxyvitamin D 3 release can last more than 4 weeks for all the tested samples. Plasma treatment can promote the release rate of 25-hydroxyvitamin D 3 . Human keratinocytes and monocytes express significantly higher levels of hCAP18/LL-37 after incubation with plasma treated and 25-hydroxyvitamin D 3 loaded PCL fibers than the cells incubated with around 10 times amount of free drug. After incubation with this fiber formulation for 5 days LL-37 in the lysis solutions of U937 cells can effectively kill the bacteria.

Preliminary investigation of the vitamin D pathway in periodontal connective tissue cells

“…Thus, it could be speculated that the more important the role a cell played in immune defense, the more active the vitamin D pathway was present in the cell, and the more hCAP‐18/LL‐37 was generated, indicating the role of the vitamin D pathway in immune defense. Other evidence also supported this hypothesis in two studies . If either the human keratinocyte cell line (Hacat) or the human monocyte cell line (U937) were treated with 25‐(OH)VD for 5 days, the generation of LL‐37 by U937 (20 to 60 ng/mg) was about 10 times higher than that by Hacat (3 to 5 ng/mg) .…”

“…Other evidence also supported this hypothesis in two studies . If either the human keratinocyte cell line (Hacat) or the human monocyte cell line (U937) were treated with 25‐(OH)VD for 5 days, the generation of LL‐37 by U937 (20 to 60 ng/mg) was about 10 times higher than that by Hacat (3 to 5 ng/mg) . In addition, it was reported that the LL‐37 concentration was approximately 400 pg/mL in the supernatant of epidermal keratinocytes, which was approximately 5 to 10 times higher than the concentrations of LL‐37 in cell supernatants of hGFs and hPDLCs in the present study.…”

Nanofiber-based Sutures Induce Endogenous Antimicrobial Peptide

“…Our recent work demonstrated that the incorporation of 25D 3 in electrospun nanofiber membranes could induce endogenous expression of the antimicrobial peptide, LL-37 [22]. To further analyze the induction of antimicrobial peptides, this study developed a method to coencapsulate 25D 3 and pam3CSK4 peptide into nanofiber sutures.…”

“…In a recently published study, we demonstrated for the first time that incorporation of 25D 3 into poly(εcaprolactone) (PCL) and poly(L-lactic acid) (PLA) fibers via electrospinning allowed sustained release over a period of 4 weeks, and the coculture of 25D 3 loaded PCL fibers with keratinocytes and monocytes greatly boosted the endogenous LL-37 production compared with the free drug [22]. Based on the model in Figure 1, co-delivery of a TLR agonist (e.g., pam3CSK4 peptide) and 25D 3 could enhance CYP27B1 expression and promote the conversion from 25D 3 to 1,25D 3 , resulting in production of more LL-37 peptide.…”

Characterization of drug delivery vehicles using atomic force microscopy: current status

“…AFM scanning revealed the surfaces to have increasing roughness with increasing levels of multiwalled-CNTs. Poly(L-lactide) and poly(ε-caprolactone) (PCL) fibres loaded with 25-hydroxyvitamin D3 (an antibiotic precursor) have been electrospun and characterised by AFM and other techniques [100]. PCL fibres were smooth, but were rougher for poly(L-lactide), and more so after than encapsulation of the drug.…”