Dietary fats induce human monocyte activation in vitro

In early atherosclerosis the frequency of activated monocytes in the peripheral circulation is amplified, and migration of monocytes into the walls of the aorta and large arteries is increased, due partly to de novo expression or activation of monocyte adhesion molecules. Although there is increasing evidence that CMRs (chylomicron remnants) are strongly atherogenic, the outcomes of interactions between blood monocytes and circulating CMRs are not known. Here, we have studied the effects of CRLPs (CMR-like particles) on THP-1 human monocyte oxidative burst. The particles induced a significant increase in reactive oxygen species within 1 h, which persisted for 24 h. We suggest that monocyte–CMR interactions may be important in early atherosclerosis when many activated monocytes are found in susceptible areas of the artery wall.

The induction of macrophages foam cell formation by chylomicron remnants

The accumulation of foam cells in the artery wall causes fatty streaks, the first lesions in atherosclerosis. LDL (low-density lipoprotein) plays a major role in foam cell formation, although prior oxidation of the particles is required. Recent studies, however, have provided considerable evidence to indicate that CMRs (chylomicron remnants), which carry dietary lipids in the blood, induce foam cell formation without oxidation. We have shown that CMRs are taken up by macrophages and induce accumulation of both triacylglycerol and cholesterol, and that the rate of uptake and amount of lipid accumulated is influenced by the type of dietary fat in the particles. Furthermore, oxidation of CMRs, in striking contrast with LDL, inhibits, rather than enhances, their uptake and induction of lipid accumulation. In addition, the lipid accumulated after exposure of macrophages to CMRs is resistant to efflux, and this may be due to its sequestration in lysosomes. These findings demonstrate that CMRs induce pro-atherogenic changes in macrophages, and that their effects may be modulated by dietary factors including oxidized fats, lipophilic antioxidants and the type of fat present.

London Wall

London Wall is a physical manifestation of the invisible city all around us; a poetic snapshot of social networking traffic from within a three-mile radius of the Museum of London. Over a ten-day period, publicly available status updates from popular websites like twitter and facebook will be selected then published as a vast array of A3 posters pasted onto a wall in the museum's foyer, revealing the idle mutterings of ourselves to ourselves as a form of concrete poetry. This commission is in the foyer and is part of relaunch the museums new galleries.