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Albumin‐bound lipids induce free cytoplasmic calcium oscillations in human osteoblast‐like cells
Author(s) -
Tsai Jon A.,
Lagumdzija Alena,
Stark André,
Kindmark Henrik
Publication year - 2006
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1316
Subject(s) - cytoplasm , calcium , albumin , osteoblast , human serum albumin , chemistry , biochemistry , serum albumin , microbiology and biotechnology , biophysics , biology , in vitro , organic chemistry
[Ca 2+ ] i oscillations were found in human osteoblast‐like cells (hOB cells) exposed to high‐lipid bovine serum albumin (BSA), but not when exposed to low‐lipid BSA. These [Ca 2+ ] i oscillations were inhibited by heptanol and suramin, which implies that gap junctions and purinergic signalling may be important for these [Ca 2+ ] i oscillations. The high‐lipid BSA preparation that was used contains arachidonic acid. [Ca 2+ ] i oscillations could be induced by low lipid albumin with arachidonic acid added. The albumin‐bound lipids were also important for osteoblast growth since DNA synthesis and the total cell protein content was higher in hOB cells exposed to high‐lipid BSA. The effect of arachidonic acid on hOB cell proliferation was bone‐donor dependent; both stimulatory and inhibitory effects were observed. The physiological importance of albumin‐bound lipids is unclear; given that albumin has only minimal contact with osteoblasts under normal conditions. Only when bone capillaries are disrupted, e.g. during a fracture, would significant amounts of albumin reach osteoblasts. Albumin‐bound lipids could therefore contribute to stimulation of osteoblast proliferation during fracture healing. Copyright © 2006 John Wiley & Sons, Ltd.