In vitro uptake of HDL-SAA by tissue macrophages during the development of AA amyloidosis in mice

Purified spleen macrophages (SM) and liver Kupffer cells (KC) were incubated with HDLSAA for up to 72 h. The uptake of serum amyloid A (SAA) by cells was determined by comparing the amount of SAA, as measured by ELISA, remaining in the supernatant at different time points of incubation. The uptake of SAA by SM significantly increased during the 72 h incubation period. SM obtained from animals undergoing an amyloidosis induction protocol had a similar uptake of SAA when compared to SM obtained from normal animals, thus suggesting that the uptake (and/ or catabolism) of HDLSAA by SM during induction of amyloidosis remains stable. No significant increase in the uptake of HDLSAA, however, was seen in KC over the 72 h incubation period. The addition of serum amyloid P protein (SAP) to the culture abrogated the uptake of SAA by SM but did not modify the uptake seen with KC. Amyloid P protein (AP) may contribute to the pathogenesis of the disease by inhibiting the cellular uptake of the precursor in the affected organs. © 1995 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.