Aims. Amyloidosis is a heterogeneous group of metabolic diseases characterized by deposition of amyloids in various tissues. The most common forms of amyloidosis are AL- and AA-amyloidosis. Current diagnosis of amyloidosis is made by histopathologic examination and Congo red-histochemistry. Further typing requires immunohistochemistry. While specificity and sensitivity of commercially available antibodies against Amyloid AA is high, antibodies against Amyloid AL show nonspecific reactivity because of conformational changes of light chain antigens in AL amyloidosis. Precise identification of the amyloid subtype is mandatory to ensure diagnosis of underlying disease and has therapeutic impact. The aim of the present study is precise diagnosis of AL-amyloidosis by matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). Methods. Renal FFPE biopsy specimens with AL-amyloidosis (n=12) and AA-amyloidosis (n=10) were subjected to trypsin and matrix deposition using the ImagePrep device (Bruker, Bremen), and were subsequently analyzed by MALDI MS in imaging and profiling mode using a Bruker Autoflex Speed. Statistical analysis was done with ClinProTools 3.0. Each analysis was performed as an independent experiment to ensure statistical independence. Results. Eleven predictive peptide signatures for AA and 10 for AL type amyloidosis were detected. MS images were compared with optical images of the Congo-red stained serial tissue sections. Both AL and AA-type amyloidosis MS images were in good concordance with the histochemistry images demonstrating regions with amyloid deposition. Conclusions. IMS is able to discern AL amyloidosis from AA-amyloidosis. Identification of various peaks is required to provide a reliable diagnostic test which can be applied in histopathological routine. MALDI IMS represents a rapid and sensitive application for the accurate characterization and typing of renal amyloidosis, and it is of diagnostic utility in addition to standard histochemical techniques.
Typing of renal amyloidosis in formalin-fixed paraffin-embedded (FFPE) biopsies specimens by MALDI imaging mass spectrometry MALDI IMS zur Typisierung von renalen Amyloidosen in formalin-fi xiertem Gewebe
Casadonte R;
2013-01-01
Abstract
Aims. Amyloidosis is a heterogeneous group of metabolic diseases characterized by deposition of amyloids in various tissues. The most common forms of amyloidosis are AL- and AA-amyloidosis. Current diagnosis of amyloidosis is made by histopathologic examination and Congo red-histochemistry. Further typing requires immunohistochemistry. While specificity and sensitivity of commercially available antibodies against Amyloid AA is high, antibodies against Amyloid AL show nonspecific reactivity because of conformational changes of light chain antigens in AL amyloidosis. Precise identification of the amyloid subtype is mandatory to ensure diagnosis of underlying disease and has therapeutic impact. The aim of the present study is precise diagnosis of AL-amyloidosis by matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). Methods. Renal FFPE biopsy specimens with AL-amyloidosis (n=12) and AA-amyloidosis (n=10) were subjected to trypsin and matrix deposition using the ImagePrep device (Bruker, Bremen), and were subsequently analyzed by MALDI MS in imaging and profiling mode using a Bruker Autoflex Speed. Statistical analysis was done with ClinProTools 3.0. Each analysis was performed as an independent experiment to ensure statistical independence. Results. Eleven predictive peptide signatures for AA and 10 for AL type amyloidosis were detected. MS images were compared with optical images of the Congo-red stained serial tissue sections. Both AL and AA-type amyloidosis MS images were in good concordance with the histochemistry images demonstrating regions with amyloid deposition. Conclusions. IMS is able to discern AL amyloidosis from AA-amyloidosis. Identification of various peaks is required to provide a reliable diagnostic test which can be applied in histopathological routine. MALDI IMS represents a rapid and sensitive application for the accurate characterization and typing of renal amyloidosis, and it is of diagnostic utility in addition to standard histochemical techniques.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
