利用激光显微切割联合质谱蛋白质组学方法进行系统性淀粉样变性分型

OBJECTIVE: To establish a novel method to determine specific type of amyloidosis through laser microdissection and mass spectrometry (LMD/MS) based proteomic analysis. METHODS: There were 138 formalin-fixed and paraffin-embedded (FFPE) biopsy samples of patients who were diagnosed as systemic amyloidosis used in this study. For each case, a 10 µm section stained with congored and positive amyloid deposits were identified under fluorescent light, followed by micro-dissection and mass spectrometry analysis. The amyloidosis subtype was confirmed based on the most abundant amyloid protein. RESULTS: The tissue types of 138 specimens were as following: subcutaneous abdominal fat accounted for 26%, tongue for 19%, gingiva for 11%, kidney for 9%, intestine for 9%, heart for 6% and others for 20%. Specific types of amyloid were accurately detected in 121 cases, including 106 (87.6%) amyloid light chain (AL) type, 7 (5.8%) amyloid trans-thy-retin (ATTR), 2 (1.7%) amyloidogenic protein A (AA), 2 (1.7%) amyloid heavy chain (AH)/AL+AH, 2 (1.7%) fibrinogen alpha chain (AFib), 1(0.8%) amyloid apolipoprotein A-type Ⅱ (AApoA-Ⅱ) and one (0.8%) amyloid lysozyme (ALys). Diagnosis of amyloidosis was excluded in 5 cases. The types of twelve cases were indeterminate by LMD/MS. On the whole, LMD/MS reached 91.3% accuracy rate in amyloid typing. Commonly involved organs (for example, heart, kidney and liver) turned out to be suitable sources of FFPE samples with typing success rate of almost 100%. In contrast, MS analysis was successful in only 83.3% of subcutaneous abdominal fat samples. CONCLUSION: LMD/MS method provided a more direct technique for accurate typing of amyloidosis in a single procedure.