Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Oct 1:97:187-199.
doi: 10.1016/j.actbio.2019.08.005. Epub 2019 Aug 3.

Eluted 25-hydroxyvitamin D3 from radially aligned nanofiber scaffolds enhances cathelicidin production while reducing inflammatory response in human immune system-engrafted mice

Shixuan Chen  1 , Liangpeng Ge  2 , Hongjun Wang  1 , Yan Cheng  3 , Santhi Gorantla  3 , Larisa Y Poluektova  3 , Adrian F Gombart  4 , Jingwei Xie  5
Affiliations

Eluted 25-hydroxyvitamin D3 from radially aligned nanofiber scaffolds enhances cathelicidin production while reducing inflammatory response in human immune system-engrafted mice

Shixuan Chen et al. Acta Biomater. .

Abstract

Vitamin D3 modulates immune response, induces endogenous antimicrobial peptide production, and enhances innate immunity to defend against infections. These findings suggest that incorporating vitamin D3 into medical devices or scaffolds could positively modulate host immune response and prevent infections. In the current study, we evaluated host responses and endogenous antimicrobial peptide production using 25-hydroxyvitamin D3 (25(OH)D3)-eluting radially aligned PCL nanofiber scaffolds in human immune system-engrafted mice. We transformed traditional 2D electrospun nanofiber membranes into radially aligned PCL nanofiber scaffolds using the concept of solid of revolution and an innovative gas-foaming technique. Such scaffolds can promote rapid cellular infiltration and neovascularization. The infiltrating immune cells within subcutaneously implanted 25(OH)D3-containing scaffolds mainly consisted of human macrophages in the M1 phase (CCR7+), mice macrophages in the M2 phase (CD206+), and human cytotoxic T cells (CD8+) other than few human T-helper cells (CD4+). The 25(OH)D3-eluting nanofiber scaffolds significantly inhibited the production of pro-inflammatory cytokines (TNF-α, IL-6), while accelerating the production of anti-inflammatory cytokines (IL-4, IL-10) within the scaffolds. Additionally, we observed increased expression of human cathelicidin LL-37 within the 25(OH)D3-eluting scaffolds, while no LL-37 expression was observed in the control. Together, these findings support further work in the design of vitamin D3-eluting medical devices or scaffolds for modulating immune response and promoting antimicrobial peptide production. This could potentially reduce the inflammatory response, prevent infections, and eventually improve success rates of implants. STATEMENT OF SIGNIFICANCE: Transplant failure of medical devices, grafts, scaffolds, and tissue-engineered constructs due to inflammation and infection causes not only economic losses but also sufferings of second operation to the patient. Positive modulation of the host response to implants, scaffolds, and tissue-engineered constructs is likely to reduce the failure rate. Vitamin D3 plays an important role in modulating the immune response. It is able to not only reduce inflammation and induce endogenous antimicrobial peptide production but also prevent multidrug resistance and other side effects of traditional antibiotics. In this study, host responses to 25-hydroxyvitamin D3 (25(OH)D3)-eluting radially aligned PCL nanofiber scaffolds were evaluated in human immune system-engrafted mice. The 25(OH)D3-eluting medical devices or scaffolds were able to modulate positive immune response and promote antimicrobial peptide production. This work presented an innate immunity-enhancing approach for reducing the inflammatory response and preventing infections, likely resulting in improvement of success rates of implants.

Keywords: 25-Hydroxyvitamin D(3); Cathelicidin production; Inflammatory response; Radially aligned nanofiber scaffolds; Sustained release.

PubMed Disclaimer

Conflict of interest statement

Conflicts of interest

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
(A) Schematic illustrating the fabrication of 25(OH)D3-loaded, radially aligned PCL nanofiber scaffolds and their subcutaneous implantation to humanized immune system mice. (B) Photograph of the expanded, radially aligned PCL nanofiber scaffolds. (C, D) SEM images show the surface structure and fiber alignment of the expanded, radially aligned PCL nanofiber scaffolds. (E) In vitro release profiles of 25(OH)D3 from PCL nanofiber mats before expansion. (F) In vitro release profiles of 25(OH)D3 from the expanded, radially aligned PCL nanofiber scaffolds.
Fig. 2.
Fig. 2.
H&E (A) and Masson trichrome (B) staining of harvested expanded, radially aligned PCL nanofiber scaffolds without and with 25(OH)D3 loading and their surrounding tissues after subcutaneous implantation for 1, 2, 4, and 8 weeks. (C) Magnified image of (B) showing the new blood vessel formation (indicated by black arrows) within the expanded, radially aligned PCL nanofiber scaffolds without and with 25(OH)D3 loading and their surrounding tissues after subcutaneous implantation for 1, 2, 4, and 8 weeks. S: scaffold area (within the dotted line), T: tissue area (outside the dotted line). The quantification of newly formed blood vessels (D) and collagen deposition (E) within the 25(OH)D3-loaded PCL nanofiber scaffold area or the PCL nanofiber scaffold area (Control) after subcutaneous implantation for 1, 2, 4, and 8 weeks. *<0.01, **p < 0.01.
Fig. 3.
Fig. 3.
Mouse CD31 (A) and human immune cell (B) distribution in the harvested expanded, radially aligned PCL nanofiber scaffolds without and with 25(OH)D3 loading and their surrounding tissues after subcutaneous implantation for 1, 2, 4, and 8 weeks. S: scaffold area (within the dotted line), T: tissue area (outside the dotted line). Human nuclei were stained with anti-human nuclei antibody in red. The quantification of mouse CD31 (C)- and human nuclei (D)-positive cells within the 25(OH)D3-loaded PCL nanofiber scaffold area (25(OH)D3) or the PCL nanofiber scaffold area (Control) after subcutaneous implantation for 1, 2, 4, and 8 weeks. **p < 0.01.
Fig. 4.
Fig. 4.
Human CD68 (red)/CCR7 (green) (A) and mouse CD68 (red)/CD206 (green) (B) immunohistochemical staining of the harvested expanded, radially aligned PCL nanofiber scaffolds without and with 25(OH)D3 loading and their surrounding tissues after subcutaneous implantation for 1, 2, 4, and 8 weeks. S: scaffold area (within the dotted line), T; tissue area (outside the dotted line). The quantification of human CD68/CCR7 (C)- and mouse CD68/CD206 (D)-positive cells within the 25(OH)D3-loaded PCL nanofiber scaffold area (25(OH)D3) or the PCL nanofiber scaffold area (Control) after subcutaneous implantation for 1, 2, 4, and 8 weeks. *p < 0.05, **p < 0.01.
Fig. 5.
Fig. 5.
Human TNF-α (A) and IL-6 (B) immunohistochemical staining of the harvested expanded, radially aligned PCL nanofiber scaffolds without and with 25(OH)D3 loading and their surrounding tissues after subcutaneous implantation for 1, 2, 4, and 8 weeks. S: scaffold area (within the dotted line), T; tissue area (outside the dotted line). The quantification of human TNF-α (C)- and IL-6 (D)-positive cells within the 25(OH)D3-loaded PCL nanofiber scaffold area (25(OH)D3) or the PCL nanofiber scaffold area (Control) after subcutaneous implantation for 1, 2, 4, and 8 weeks. *p < 0.05, **p < 0.01.
Fig. 6.
Fig. 6.
Human IL-4 (A) and IL-10 (B) immunohistochemical staining of the harvested expanded, radially aligned PCL nanofiber scaffolds without and with 25(OH)D3 loading and their surrounding tissues after subcutaneous implantation for 1, 2, 4, and 8 weeks. S: scaffold area (within the dotted line), T; tissue area (outside the dotted line). The quantification of human IL-4 (C) and mouse IL-10 (D)-positive cells within the 25(OH)D3-loaded PCL nanofiber scaffold area (25(OH)D3) or the PCL nanofiber scaffold area (Control) after subcutaneous implantation for 1, 2, 4, and 8 weeks. *p <0.05, **p < 0.01.
Fig. 7.
Fig. 7.
(A) The human cathelicidin immunohistochemical staining of the harvested expanded, radially aligned PCL nanofiber scaffolds without and with 25(OH)D3 loading and their surrounding tissues after subcutaneous implantation for 1, 2, 4, and 8 weeks. S: scaffold area (within the dotted line), T; tissue area (outside the dotted line). (B) The quantification of human cathelicidin-positive cells within the 25(OH)D3-loaded PCL nanofiber scaffold area (25(OH)D3) or the PCL nanofiber scaffold area (Control) after subcutaneous implantation for 1, 2, 4, and 8 weeks. *p <0.05, **p < 0.01.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Franz S, Rammelt S, Scharnweber D, Simon JC, Immune responses to implants–a review of the implications for the design of immunomodulatory biomaterials, Biomaterials 32(2011)6692–6709. - PubMed
    1. Yanez M, Blanchette J, Jabbarzadeh E, Modulation of Inflammatory Response to Implanted Biomaterials Using Natural Compounds, Curr. Pharm. Des. 23(2017)6347–6357. - PMC - PubMed
    1. Chen S, Ge L, Gombart AF, Shuler FD, Carlson MA, Reilly DA, Xie J, Nanofiber-based sutures induce endogenous antimicrobial peptide, Nanomedicine (Lond.) 12(2017)2597–2609. - PMC - PubMed
    1. Hewison M, Antibacterial effects of vitamin D, Nat. Rev. Endocrinol. 7(2011)337. - PubMed
    1. Zhang Y, Leung DYM, Richers BN, Liu Y, Remigio LK, Riches DW, Goleva E, Vitamin D inhibits monocyte/macrophage proinflammatory cytokine production by targeting MAPK phosphatase-1, J. Immunol. (2012)1102412. - PMC - PubMed

Publication types