Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Acta Biomater. 2013 Dec;9(12):9281-91. doi: 10.1016/j.actbio.2013.08.002. Epub 2013 Aug 9.

Ca(2+) released from calcium alginate gels can promote inflammatory responses in vitro and in vivo.

Author information

  • 1School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.

Abstract

In general, alginate hydrogels are considered to be biologically inert and are commonly used for biomedical purposes that require minimum inflammation. However, Ca(2+), which is commonly used to crosslink alginate, is a critical second messenger in immune cell signaling, and little has been done to understand its effect on immune cell fate when delivered as a component of alginate gels. We found that dendritic cells (DCs) encapsulated in Ca(2+)-crosslinked alginate (calcium alginate) secreted at least fivefold more of the inflammatory cytokine IL-1β when compared to DCs encapsulated in agarose and collagen gels, as well as DCs plated on tissue-culture polystyrene (TCPS). Plating cells on TCPS with the alginate polymer could not reproduce these results, whereas culturing DCs on TCPS with increasing concentrations of Ca(2+) increased IL-1β, MHC class II and CD86 expression in a dose-dependent manner. In agreement with these findings, calcium alginate gels induced greater maturation of encapsulated DCs compared to barium alginate gels. When injected subcutaneously in mice, calcium alginate gels significantly upregulated IL-1β secretion from surrounding tissue relative to barium alginate gels, and similarly, the inflammatory effects of LPS were enhanced when it was delivered from calcium alginate gels rather than barium alginate gels. These results confirm that the Ca(2+) used to crosslink alginate gels can be immunostimulatory and suggest that it is important to take into account Ca(2+)'s bioactive effects on all exposed cells (both immune and non-immune) when using calcium alginate gels for biomedical purposes. This work may strongly impact the way people use alginate gels in the future as well as provide insights into past work utilizing alginate gels.

Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

KEYWORDS:

Alginate; Ca(2+) signaling; Dendritic cell; IL-1β; Tissue engineering

PMID:
23938198
[PubMed - indexed for MEDLINE]
PMCID:
PMC3867449
[Available on 2014/12/1]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science Icon for PubMed Central
    Loading ...
    Write to the Help Desk