The presence of cytoplasmic lipid droplets is not sufficient to account for neutral lipid signals in the 1H MR spectra of neutrophils.
Stimulation of human peripheral blood neutrophils with lipopolysaccharide (LPS), arachidonic acid (AA) and oleic acid (OA) resulted in significant increases in cytoplasmic lipid droplets. This phenomenon was also observed in enucleated and degranulated cytoplasts prepared from neutrophils stimulated with LPS. In contrast, only LPS and high concentrations of OA (10 microM) produced an increase in the lipid intensities of the MR spectra of neutrophils as determined by COSY cross peak volume measurements. Lipid intensities in cells stimulated with OA (2.5 microM) and AA (2.5 microM) and phorbol myristate acetate (20 nM) were not elevated. LPS stimulation of resting cytoplasts resulted in increased lipid droplets but not MR lipid intensities. These data suggest that while cytoplasmic lipid droplets may correlate with MR lipid intensity under some circumstances, their presence is not sufficient to account for increased neutral lipid signals.
May
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GL
Center for Infectious Diseases and Microbiology, University of Sydney, Westmead Hospital, NSW Australia.
Sztelma
K
K
Sorrell
T C
TC
D016718:Arachidonic Acid / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D006859:Hydrogen; D002479:Inclusion Bodies / Q000187:drug effects / Q000378:metabolism; D050356:Lipid Metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism*; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D012486:Salmonella typhimurium; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D008070:Lipopolysaccharides; D009829:Oleic Acids; D016718:Arachidonic Acid; D019301:Oleic Acid; D006859:Hydrogen; D013755:Tetradecanoylphorbol Acetate