Dear Agnes,

Can you give me more information? Do you need to extract circulating (extracellular) miRNAs or miRNAs from the blood cells?

Dear @ Prabin Upadhyaya

We have tried to extract circulating microRNA in hypertriglyceridemic and hypercholesterolemic plasma. This type of samples clogged the column of separation. And an extraction with Trizol gave not really good performance and quality. What can we test again?

If you have some advice, you are welcomed.

Thanks,

Agnes

Extracting circulating miRNAs can be difficult, specially, when you draw blood postprandially because of the higher lipid content in the blood.

And yes, many suggest that acid guanidium thiocyanate-phenol chloroform (or Trizol) method does not work very well when extracting miRNAs from serum or plasma. However, when I extract total RNAs from the cells using Trizol, I get nice amount of miRNAs as well in the total RNA. I do not know why there are reports that efficiency is low and other contaminant are found when extracting circulating miRNAs using Trizol, though the principle of extraction are the same. Explanation regarding this will be highly appreciated.

Circulating miRNAs in the blood are found inside the exosomes, because of which the miRNAs are highly stable and are protected from RNases. There are some commercial kits that extract exosomes, in which this one from qiagen is considered most efficient.

https://www.qiagen.com/us/shop/sample-technologies/tumor-cells-and-exosomes/mircury-exosome-kits/#orderinginformation

Once you are extract exosomes from your lipid rich blood, using the same kit you can extract the pure miRNAs.

I hope this suggestion works, Best wishes