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Diagnosis and Classification of Amyloidosis



Mass Spectrometry-Based Proteomic Analysis of Amyloidosis

Slide 10

December 2009

To overcome these difficulties, we developed a new methodology to type amyloid deposits in paraffin-embedded tissues. The method uses the precision of laser microdissection and analytical sensitivity and specificity of tandem mass spectrometry (MS). In this method, the amyloid plaques are microdissected by laser from Congo red-stained paraffin sections. Often a single section of a clinical biopsy material (heart, kidney or bone marrow) is enough to obtain results.

For each test, approximately the area of 2 glomeruli would give enough peptide yield to type the amyloid. The microdissected amyloid plaques are digested into peptides using trypsin. The peptide solution is separated by HPLC and sprayed into mass spectrometry using a method called electrospray ionization (ESI). This method ionizes the peptides so that mass spectrometry could detect them.  Tandem mass spectrometry then detects mass/charge ratio of the peptides as well as their fragmentation products. These measurements are then interrogated against public human protein databases using software algorithms. The algorithms identify the best peptide/protein matches for a given peptide and its daughter ions.

Analysis of Amyloidosis

 


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