My concern lies, when I try to isolate and purify with optiprep the exosomal fraction from the blood of melanoma patients, I can see different pellets in the ultracentrifugation. I would like to know, does LDL (Low density Lipoprotiens) and HDL pellets down with exosomes and how can we separate them, is there a method to separate them?
Hi，it is very hard to separate the exosomes from LDL HDL,because of the same density and size.So,when I need the protein of the Exosomes , I dissociation the exosomes ,and then tracentrifugation in 120000g to pellet the LDL and HDL again .
Hi,
Exosomes are membrane vesicles while lipoprotein particles carry non-polar lipids (non-miscible with water), therefore one difference between lipoprotein particles and the exosomes is the lipid content. But when using density gradient ultracentrifugation, extracellular vesicles would co-sediment with HDL particles because they have similar density. (http://www.metves.eu/downloads/articles/Yuana_2014_JEV_Co-isolation_of_vesicles.pdf)
Browsing the internet I found this: http://www.biocat.com/products/EXOLP5A-1-SBI and they claim to deplete lipoprotein particles from plasma or serum before exosome precipitation. I hope this helps!
Hello,
Nothing do add on the difference between exosomes, LDL and HDL. I have attached two papers where the isolation and characterization of exosomes is described in greater detail. One is dealing with exosomes from grafted B16-F10 cells (H Peinado, Nat Med 18, 2012) and the other generally with exosomes and microsomes in clinical blood samples.
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