Rapid detection of wild-type and mutated transthyretins

Abstract

Background: Familial amyloid polyneuropathy is caused by a variant transthyretin, which is a serum protein secreted by the liver. We previously reported that mutated transthyretins were detected in serum samples by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The aim of this study was to evaluate the clinical usefulness of SELDI-TOF MS for diagnosis of transthyretin-related amyloidosis. Methods: We used 106 serum samples obtained from patients who were clinically suspected of having amyloidosis between February 2011 and April 2014. SELDI-TOF MS allowed analysis for transthyretin via a 3-h one-step procedure. Results: Of the 106 patients, 51 are transthyretin amyloidosis. Mutated transthyretins were detected in serum samples from 30 of 51 patients with transthyretin amyloidosis. The results of genetic analysis showed that all of those patients had mutations in the transthyretin gene. For all 18 patients with senile systemic amyloidosis of 51 patients with transthyretin amyloidosis, SELDI-TOF MS detected only wild-type transthyretin peaks, not mutated transthyretin peaks. Conclusion: SELDI-TOF MS is a clinically useful tool for diagnosis of transthyretin-related amyloidosis.

Use of biomarkers to diagnose and manage cardiac amyloidosis

“…Electrophoretic techniques allow to evaluate multiple samples at the same time, reaching a 100% specificity for many TTR mutations. 34,35 Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), [36][37][38] electrospray ionization (ESI), [39][40][41] and surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) 42,43 have been proposed as mass spectrometry methods to identify TTR variants, but their clinical use is limited by the complex equipment and preparation required. Recently, a novel MALDI-TOF approach has been developed, which does not require a sample pre-purification phase and can provide results within 30 min.…”

New simple and quick method to analyze serum variant transthyretins: direct MALDI method for the screening of hereditary transthyretin amyloidosis

“…This method required only 30 min to obtain results. Other mass spectrometric methods, such as IP-MALDI, IP-ESI, and SELDI, needed significant time to detect variant TTRs in serum samples because of cumbersome pre-purification such as immunoprecipitation with anti-TTR antibodies or use of the ProteinChip system (Table 2) [7–14]. Direct MALDI is thus a simple means of detecting TTR variants for clinical screening compared with other methods.…”

“…Mass spectrometry (MS) is a powerful tool that can detect small molecular changes in proteins. Because the molecular masses of variant TTRs with amino acid exchanges differ from that of wild-type (WT) TTR, we developed diagnostic methods to detect variant TTRs in serum samples by means of several different mass spectrometric analyses such as matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) MS with immunoprecipitated (IP) serum TTR (IP-MALDI) [7–9], electrospray ionization (ESI) MS with IP serum TTR (IP-ESI) [10–12], and surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) MS ProteinChip system [13, 14]. Although those methods are valuable for screening ATTRv amyloidosis and double-checking TTR variants in addition to genetic testing of the TTR gene, they require significant time to analyze variant TTRs, and they also sometimes fail to detect TTRs because of technical difficulties related to the cumbersome immunoprecipitation with anti-TTR antibodies.…”

Systemic amyloidoses and proteomics: The state of the art

“…Our group employed a strategy based on the use of anti-FLC antibodies covalently linked to agarose beads in microcentrifuge tubes [51] . In alternative to immunoprecipitation, in the case of TTR, chip-based enrichment in the context of SELDI-TOF MS-based methods have been described [61] , [62] . Recently, a method that couples capillary zone electrophoresis with MS has been reported for screening of TTR variants in serum samples [63] .…”

“…The main focus of former studies was directed towards qualitative characterization, especially for detecting amyloidogenic mutations. The developments of diagnostic methods has been particularly fertile in ATTR amyloidosis, in which MS has proved informative to evidence mass shifts in the digested [60] , [66] , [67] or in the intact protein [61] , [62] , [68] , [69] , [70] . While several past studies used MALDI-TOF and peptide mass fingerprinting for identifying mutations-bearing peptides [66] , [67] , more recent approaches confirm and locate the variant by MS/MS sequencing or top-down analysis, using high-resolution instruments [69] .…”