A Pilot Study of Rare Renal Amyloidosis Based on FFPE Proteomics

Abstract

Renal amyloidosis typically manifests albuminuria, nephrotic-range proteinuria, and ultimately progresses to end-stage renal failure if diagnosed late. Different types of renal amyloidosis have completely different treatments and outcomes. Therefore, amyloidosis typing is essential for disease prognosis, genetic counseling and treatment. Thirty-six distinct proteins currently known to cause amyloidosis that have been described as amyloidogenic precursors, immunohistochemistry (IHC) or immunofluorescence (IF), can be challenging for amyloidosis typing especially in rare or hereditary amyloidosis in clinical practice. We made a pilot study that optimized the proteomics pre-processing procedures for trace renal amyloidosis formalin-fixed paraffin-embedded (FFPE) tissue samples, combined with statistical and bioinformatics analysis to screen out the amyloidosis-related proteins to accurately type or subtype renal amyloidosis in order to achieve individual treatment. A sensitive, specific and reliable FFPE-based proteomics analysis for trace sample manipulation was developed for amyloidosis typing. Our results not only underlined the great promise of traditional proteomics and bioinformatics analysis using FFPE tissues for amyloidosis typing, but also proved that retrospective diagnosis and analysis of previous cases laid a solid foundation for personalized treatment.

Precise diagnosis and typing of early-stage renal immunoglobulin-derived amyloidosis by label-free quantification of parallel reaction monitoring-based targeted proteomics

“…Contaminations by serum proteins or nonspecific charge interaction between the amyloid deposits and the reagent antibody can lead to false-positive staining [4,5,30]. Proteomics aims to identify all protein information in samples such as cells or tissues [6,19]. FFPE-based proteomics is unbiased to identify all amyloid fiber protein types in a single assay, unlike immunologic-based techniques that a single test would only identify a single amyloid fibril protein type [9,30].…”

“…Amyloidosis can cause systemic or local lesions; kidney was the most commonly affected organ by systemic amyloidosis [4,5]. Renal amyloidosis is a rare and intractable protein misfolding disorder which prompts progressive renal insufficiency [6]. Renal amyloidosis manifests as proteinuria, edema, and hypoalbuminemia, resulting in nephrotic syndrome via fibril deposition in the mesangium and capillary loops of the glomerulus, vessels, as well as interstitium [7,8].…”

“…Clinically, the most common types of amyloid fibrils in patients with renal amyloidosis are derived from fragments of immunoglobulin (Ig) lambda or kappa light-chain (AL), and rarely Ig heavy chains only (AH) or heavy chains and light chains (AHL) [9,10]. Although most types of amyloidosis are progressive, often fatal, and manifest similarly, treatment strategies are drastically different [6,11]. Establishing the precise nature of amyloid precursor protein is of paramount importance in guiding the clinical management of amyloidosis by reducing the production of the respective underlying etiology [5].…”