The role of dietary microparticles and calcium in apoptosis and interleukin-1β release of intestinal macrophages

Stephen M. Evans, Paul Ashwood, Alice Warley, Fatmire Berisha, Richard P H Thompson, Jonathan J. Powell

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Background & Aims: The intestinal mucosa is exposed to micron-sized, man-made exogenous particles (e.g., titanium dioxide) and freshly formed endogenous particles (calcium phosphate). A role for such microparticles in inflammation has been proposed, and here we examined their effects on lamina propria mononuclear cells. Methods: Lamina propria mononuclear cells were isolated from patients with and without inflammatory bowel disease and incubated with lipopolysaccharide, titanium dioxide, and calcium ± citrate, as well as a conjugate of lipopolysaccharide, calcium, and titanium dioxide. Interleukin-1β interleukin-1 receptor antagonist were measured by enzyme-linked immunosorbent assay in culture supernatants and macrophage apoptosis by flow cytometry. Mechanistic studies were undertaken in normal peripheral blood mononuclear cells. Results: Baseline levels of interleukin-1β and macrophage apoptosis were greater in inflammatory bowel disease than in normal lamina propria mononuclear cells. Lipopolysaccharide and titanium dioxide had no additional effect, but calcium, and more so the conjugate, induced interleukin-1β release in proportion to the degree of inflammation. Citrate, used to prevent in situ calcium phosphate formation, negated lamina propria mononuclear cell stimulation. Macrophage apoptosis was also increased by calcium and the conjugate. In peripheral blood mononuclear cells, inhibition of caspase 1 reduced interleukin-1β secretion, whereas blockade of phagocytosis inhibited calcium-induced apoptosis and interleukin-1β release. Conclusions: The endogenous luminal microparticle calcium phosphate Promotes apoptosis of intestinal macrophages. Concomitantly, interleukin-1β is released, which is enhanced in the presence of inflamed cells and/or exogenous dietary microparticles. Endogenous or exogenous microparticles could aggravate the ongoing inflammation of inflammatory bowel disease.

Original languageEnglish (US)
Pages (from-to)1543-1553
Number of pages11
JournalGastroenterology
Volume123
Issue number5
StatePublished - Nov 1 2002
Externally publishedYes

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Dietary Calcium
Interleukin-1
Macrophages
Apoptosis
Mucous Membrane
Inflammatory Bowel Diseases
Calcium
Lipopolysaccharides
Inflammation
Blood Cells
Calcium Citrate
Caspase 1
Interleukin-1 Receptors
Intestinal Mucosa
Phagocytosis
Citric Acid
Flow Cytometry
Enzyme-Linked Immunosorbent Assay
titanium dioxide
calcium phosphate

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Evans, S. M., Ashwood, P., Warley, A., Berisha, F., Thompson, R. P. H., & Powell, J. J. (2002). The role of dietary microparticles and calcium in apoptosis and interleukin-1β release of intestinal macrophages. Gastroenterology, 123(5), 1543-1553.

The role of dietary microparticles and calcium in apoptosis and interleukin-1β release of intestinal macrophages. / Evans, Stephen M.; Ashwood, Paul; Warley, Alice; Berisha, Fatmire; Thompson, Richard P H; Powell, Jonathan J.

In: Gastroenterology, Vol. 123, No. 5, 01.11.2002, p. 1543-1553.

Research output: Contribution to journalArticle

Evans, SM, Ashwood, P, Warley, A, Berisha, F, Thompson, RPH & Powell, JJ 2002, 'The role of dietary microparticles and calcium in apoptosis and interleukin-1β release of intestinal macrophages', Gastroenterology, vol. 123, no. 5, pp. 1543-1553.
Evans, Stephen M. ; Ashwood, Paul ; Warley, Alice ; Berisha, Fatmire ; Thompson, Richard P H ; Powell, Jonathan J. / The role of dietary microparticles and calcium in apoptosis and interleukin-1β release of intestinal macrophages. In: Gastroenterology. 2002 ; Vol. 123, No. 5. pp. 1543-1553.
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