Towards an improved early diagnosis of neurodegenerative diseases: the emerging role of in vitro conversion assays for protein amyloids

Candelise, Niccolò; Baiardi, Simone; Franceschini, Alessia; Rossi, Marcello; Parchi, Piero

doi:10.1186/s40478-020-00990-x

Cited by 50 publications

(44 citation statements)

References 96 publications

(181 reference statements)

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“…Of course, RT-QuIC assays have revolutionized the diagnostic approach not only in human prion disorders but also in other proteinopathies and in particular in α-synucleinopathies. 32 , 33 Previous studies showed that α-syn RT-QuIC detects α-syn aggregates in CSF of patients with DLB, with high diagnostic accuracy. 12–17 …”

Section: Discussionmentioning

confidence: 99%

Alpha-synuclein seeds in olfactory mucosa and cerebrospinal fluid of patients with dementia with Lewy bodies

Perra

Bongianni

Novi

et al. 2021

Brain Communications

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In patients with suspected dementia with Lewy bodies the detection of the disease-associated α-synuclein in easily accessible tissues amenable to be collected using minimally invasive procedures, remains a major diagnostic challenge. This approach has the potential to take advantage of modern molecular assays for the diagnosis of α–synucleinopathy and, in turn, to optimize the recruitment and selection of patients in clinical trials, using drugs directed at counteracting α-synuclein aggregation. In this study, we explored the diagnostic accuracy of α-synuclein real-time quaking-induced conversion assay by testing olfactory mucosa and CSF in patients with a clinical diagnosis of probable (n = 32) or prodromal (n = 5) dementia with Lewy bodies or mixed degenerative dementia (dementia with Lewy bodies/Alzheimer’s disease) (n = 6). Thirty-eight patients with non-α-synuclein-related neurodegenerative and non-neurodegenerative disorders, including Alzheimer’s disease (n = 10), sporadic Creutzfeldt-Jakob disease (n = 10), progressive supranuclear palsy (n = 8), corticobasal syndrome (n = 1), fronto-temporal dementia (n = 3) and other neurological conditions (n = 6) were also included, as controls. All 81 patients underwent olfactory swabbing while CSF was obtained in 48 participants. At the initial blinded screening of olfactory mucosa samples, 38 out of 81 resulted positive while CSF was positive in 19 samples out of 48 analyzed. After unblinding of the results, 27 positive olfactory mucosa were assigned to patients with probable dementia with Lewy bodies, five with prodromal dementia with Lewy bodies and three to patients with mixed dementia, as opposed to three out 38 controls. Corresponding results of CSF testing disclosed 10 out 10 positive samples in patients with probable dementia with Lewy bodies and six out of six with mixed dementia, in addition to three out of 32 for controls. The accuracy among results of real-time quaking-induced conversion assays and clinical diagnoses was 86.4% in the case of olfactory mucosa and 93.8% for CSF. For the first time, we showed that α-synuclein real-time quaking induced conversion assay detects α-synuclein aggregates in olfactory mucosa of patients with dementia with Lewy bodies and with mixed dementia. Additionally, we provided preliminary evidence that the combined testing of olfactory mucosa and CSF raised the concordance with clinical diagnosis potentially to 100%. Our results suggest that nasal swabbing might be considered as a first line screening procedure in patients with a diagnosis of suspected dementia with Lewy bodies followed by CSF analysis, as a confirmatory test, when the result in the olfactory mucosa is incongruent with the initial clinical diagnosis.

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Section: Discussionmentioning

confidence: 99%

Alpha-synuclein seeds in olfactory mucosa and cerebrospinal fluid of patients with dementia with Lewy bodies

Perra

Bongianni

Novi

et al. 2021

Brain Communications

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“…Thelast couple of years have witnessed arenewed interest for the detection of aSyn aggregation as apotential biomark-er for Parkinsonsd isease and other synucleinopathies. [24] PMCAa nd RT-quIC assays were initially developed for the detection of the misfolded prion protein (PrP Sc )and are now used for the diagnostic of transmissible spongiform encepha- (left) and after (right) amplification. 2 mLofC SF were diluted 10 times in 20 mM aSyn K23Q monomer and 10 mMThT.Amplification was carried out at 55 8 8C, without shaking, for 5hours.…”

Section: Forschungsartikel Discussionmentioning

confidence: 99%

Single‐Molecule Counting Coupled to Rapid Amplification Enables Detection of α‐Synuclein Aggregates in Cerebrospinal Fluid of Parkinson's Disease Patients

et al. 2021

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α‐Synuclein aggregation is a hallmark of Parkinson's disease and a promising biomarker for early detection and assessment of disease progression. The prospect of a molecular test for Parkinson's disease is materializing with the recent developments of detection methods based on amplification of synuclein seeds (e.g. RT‐QuIC or PMCA). Here we adapted single‐molecule counting methods for the detection of α‐synuclein aggregates in cerebrospinal fluid (CSF), using a simple 3D printed microscope. Single‐molecule methods enable to probe the early events in the amplification process used in RT‐QuIC and a precise counting of ThT‐positive aggregates. Importantly, the use of single‐molecule counting also allows a refined characterization of the samples and fingerprinting of the protein aggregates present in CSF of patients. The fingerprinting of size and reactivity of individual aggregate shows a unique signature for each PD patients compared to controls and may provide new insights on synucleinopathies in the future.

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“…Detection of abnormal aggregated α-syn in CSF of DLB patients by the RT-QuIC assay was first reported by Fairfoul et al (2016); this was followed by multiple clinical studies. At present, diagnostic methods using skin (Orru et al, 2017) or OM (Orru et al, 2014;Bongianni et al, 2017), which includes CSF, have been reported (Satoh et al, 2017;Ascari et al, 2020;Candelise et al, 2020).…”

Section: α-Synuclein and Real-time Quaking-induced Conversionmentioning

confidence: 99%

Development of α-Synuclein Real-Time Quaking-Induced Conversion as a Diagnostic Method for α-Synucleinopathies

Nakagaki

Nishida

Satoh

2021

Front. Aging Neurosci.

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Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy are characterized by aggregation of abnormal α-synuclein (α-syn) and collectively referred to as α-synucleinopathy. Because these diseases have different prognoses and treatments, it is desirable to diagnose them early and accurately. However, it is difficult to accurately diagnose these diseases by clinical symptoms because symptoms such as muscle rigidity, postural dysreflexia, and dementia sometimes overlap among these diseases. The process of conformational conversion and aggregation of α-syn has been thought similar to that of abnormal prion proteins that cause prion diseases. In recent years, in vitro conversion methods, such as real-time quaking-induced conversion (RT-QuIC), have been developed. This method has succeeded in amplifying and detecting trace amounts of abnormal prion proteins in tissues and central spinal fluid of patients by inducing conversion of recombinant prion proteins via shaking. Additionally, it has been used for antemortem diagnosis of prion diseases. Recently, aggregated α-syn has also been amplified and detected in patients by applying this method and many clinical studies have examined diagnosis using tissues or cerebral spinal fluid from patients. In this review, we discuss the utility and problems of α-syn RT-QuIC for antemortem diagnosis of α-synucleinopathies.

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Towards an improved early diagnosis of neurodegenerative diseases: the emerging role of in vitro conversion assays for protein amyloids

Cited by 50 publications

References 96 publications

Alpha-synuclein seeds in olfactory mucosa and cerebrospinal fluid of patients with dementia with Lewy bodies

Alpha-synuclein seeds in olfactory mucosa and cerebrospinal fluid of patients with dementia with Lewy bodies

Single‐Molecule Counting Coupled to Rapid Amplification Enables Detection of α‐Synuclein Aggregates in Cerebrospinal Fluid of Parkinson's Disease Patients

Development of α-Synuclein Real-Time Quaking-Induced Conversion as a Diagnostic Method for α-Synucleinopathies

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