Angela Mammana

Bio: Angela Mammana is an academic researcher from University of Bologna. The author has contributed to research in topics: Dementia with Lewy bodies & Lewy body. The author has an hindex of 6, co-authored 11 publications receiving 167 citations.

Ultrasensitive RT-QuIC assay with high sensitivity and specificity for Lewy body-associated synucleinopathies.

Abstract: The clinical diagnosis of synucleinopathies, including Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), is challenging, especially at an early disease stage, due to the heterogeneous and often non-specific clinical manifestations. The discovery of reliable specific markers for synucleinopathies would consequently be of great aid to the diagnosis and management of these disorders. Real-Time Quaking-Induced Conversion (RT-QuIC) is an ultrasensitive technique that has been previously used to detect self-templating amyloidogenic proteins in the cerebrospinal fluid (CSF) and other biospecimens in prion disease and synucleinopathies. Using a wild-type recombinant α-synuclein as a substrate, we applied RT-QuIC to a large cohort of 439 CSF samples from clinically well-characterized, or post-mortem verified patients with parkinsonism or dementia. Of significance, we also studied patients with isolated REM sleep behavior disorder (iRBD) (n = 18) and pure autonomic failure (PAF) (n = 28), representing clinical syndromes that are often caused by a synucleinopathy, and may precede the appearance of parkinsonism or cognitive decline. The results show that our RT-QuIC assay can accurately detect α-synuclein seeding activity across the spectrum of Lewy Body (LB)-related disorders (LBD), including DLB, PD, iRBD, and PAF, with an overall sensitivity of 95.3%. In contrast, all but two patients with MSA showed no α-synuclein seeding activity in the applied experimental setting. The analysis of the fluorescence response reflecting the amount of α-synuclein seeds revealed no significant differences between the clinical syndromes associated with LB pathology. Finally, the assay demonstrated 98% specificity in a neuropathological cohort of 101 cases lacking LB pathology. In conclusion, α-synuclein RT-QuIC provides an accurate marker of synucleinopathies linked to LB pathology and may have a pivotal role in the early discrimination and management of affected patients. The finding of no α-synuclein seeding activity in MSA seems to support the current view that MSA and LBD are associated with different conformational strains of α-synuclein.

CSF biomarkers of neuroinflammation in distinct forms and subtypes of neurodegenerative dementia.

Abstract: In neurodegenerative dementias (NDs) such as prion disease, Alzheimer’s disease (AD), and frontotemporal lobar degeneration (FTLD), protein misfolding leads to the tissue deposition of protein aggregates which, in turn, trigger neuroinflammation and neurodegeneration. Cerebrospinal fluid (CSF) biomarkers have the potential to reflect different aspects of these phenomena across distinct clinicopathological subtypes and disease stages. We investigated CSF glial markers, namely chitotriosidase 1 (CHIT1), chitinase-3-like protein 1 (YKL-40) and glial fibrillary acidic protein (GFAP) in prion disease subtypes (n = 101), AD (n = 40), clinicopathological subgroups of FTLD (n = 72), and controls (n = 40) using validated, commercially available ELISA assays. We explored glial biomarker levels’ associations with disease variables and neurodegenerative CSF biomarkers and evaluated their diagnostic accuracy. The genotype of the CHIT1 rs3831317 polymorphic site was also analyzed. Each ND group showed increased levels of CHIT1, YKL-40, and GFAP compared to controls with a difference between prion disease and AD or FTLD limited to YKL-40, which showed higher values in the former group. CHIT1 levels were reduced in both heterozygotes and homozygotes for the CHIT1 24-bp duplication (rs3831317) in FTLD and controls, but this effect was less significant in AD and prion disease. After stratification according to molecular subgroups, we demonstrated (i) an upregulation of all glial markers in Creutzfeldt-Jakob disease VV2 compared to other disease subtypes, (ii) a difference in CHIT1 levels between FTLD with TAU and TDP43 pathology, and (iii) a marked increase of YKL-40 in FTLD with amyotrophic lateral sclerosis (ALS) in comparison with FTLD without ALS. In prion disease, glial markers correlated with disease stage and were already elevated in one pre-symptomatic case of Gerstmann-Straussler-Scheinker disease. Regarding the diagnostic value, YKL-40 was the only glial marker that showed a moderate accuracy in the distinction between controls and NDs. NDs share a CSF profile characterized by increased levels of CSF CHIT1, YKL-40, and GFAP, which likely reflects a common neuroinflammatory response to protein misfolding and aggregation. CSF glial markers of neuroinflammation demonstrate limited diagnostic value but have some potential for monitoring the clinical and, possibly, preclinical phases of NDs.

Diagnostic Value of the CSF α-Synuclein Real-Time Quaking-Induced Conversion Assay at the Prodromal MCI Stage of Dementia With Lewy Bodies.

Abstract: Objective To investigate whether the CSF α-synuclein (α-syn) real-time quaking-induced conversion (RT-QuIC) assay accurately identifies patients with mild cognitive impairment (MCI) due to probable Lewy body (LB) disease. Methods We applied α-syn RT-QuIC to 289 CSF samples obtained from 2 independent cohorts, including 81 patients with probable MCI-LB (age 70.7 ± 6.6 years, 13.6% female, Mini-Mental State Examination [MMSE] score 26.1 ± 2.4), 120 with probable MCI due to Alzheimer disease (AD) (age 68.6 ± 7.4 years, 45.8% female, MMSE score 25.5 ± 2.8), and 30 with unspecified MCI (age 65.4 ± 9.3 years, 30.0% female, MMSE score 27.0 ± 3.0). Fifty-eight individuals with no cognitive decline or evidence of neurodegenerative disease and 121 individuals lacking brain α-syn deposits at the neuropathologic examination were used as controls. Results RT-QuIC identified patients with MCI-LB against cognitively unimpaired controls with 95% sensitivity, 97% specificity, and 96% accuracy and showed 98% specificity in neuropathologic controls. The accuracy of the test for MCI-LB was consistent between the 2 cohorts (97.3% vs 93.7%). Thirteen percent of patients with MCI-AD also had a positive test; of note, 44% of them developed 1 core or supportive clinical feature of dementia with Lewy bodies (DLB) at follow-up, suggesting an underlying LB copathology. Conclusions These findings indicate that CSF α-syn RT-QuIC is a robust biomarker for prodromal DLB. Further studies are needed to fully explore the added value of the assay to the current research criteria for MCI-LB. Classification of Evidence This study provides Class III evidence that CSF α-syn RT-QuIC accurately identifies patients with MCI-LB.

Diagnostic value of surrogate CSF biomarkers for Creutzfeldt-Jakob disease in the era of RT-QuIC.

Abstract: Prion real-time quaking-induced conversion (RT-QuIC) is emerging as the most potent assay for the in vivo diagnosis of Creutzfeldt–Jakob disease (CJD), but its full application, especially as a screening test, is limited by suboptimal substrate availability, reagent costs, and incomplete assay standardization. Therefore, the search for the most informative cerebrospinal fluid (CSF) surrogate biomarker is still of primary importance. We compared the diagnostic accuracy of CSF protein 14-3-3, measured with both western blot (WB) and enzyme-linked immunosorbent assay (ELISA), total (t)-tau and neurofilament light chain protein (NfL) alone or in combination with RT-QuIC in 212 subjects with rapidly progressive dementia in which we reached a highly probable clinical diagnosis at follow-up or a definite neuropathological diagnosis. T-tau performed best as surrogate CSF biomarker for the diagnosis of CJD (91.3% sensitivity and 78.9% specificity). The 14-3-3 ELISA assay demonstrated a slightly higher diagnostic value compared to the WB analysis (76.9% vs. 72.2%), but both methods performed worse than the t-tau assay. NfL was the most sensitive biomarker for all sCJD subtypes (> 95%), including those with low values of t-tau or 14-3-3, but showed the lowest specificity (43.1%). When ELISA-based biomarkers were adopted as screening tests followed by RT-QuIC, t-tau correctly excluded a higher number of non-CJD cases compared to NfL and 14-3-3 ELISA. Our study showed that among the CSF surrogate biomarkers of potential application for the clinical diagnosis of CJD, t-tau performs best either alone or as screening test followed by RT-QuIC as a second-level confirmatory test.

Association between CSF alpha-synuclein seeding activity and genetic status in Parkinson's disease and dementia with Lewy bodies.

Abstract: The clinicopathological heterogeneity in Lewy-body diseases (LBD) highlights the need for pathology-driven biomarkers in-vivo. Misfolded alpha-synuclein (α-Syn) is a lead candidate based on its crucial role in disease pathophysiology. Real-time quaking-induced conversion (RT-QuIC) analysis of CSF has recently shown high sensitivity and specificity for the detection of misfolded α-Syn in patients with Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In this study we performed the CSF RT-QuIC assay in 236 PD and 49 DLB patients enriched for different genetic forms with mutations in GBA, parkin, PINK1, DJ1, and LRRK2. A subgroup of 100 PD patients was also analysed longitudinally. We correlated kinetic seeding parameters of RT-QuIC with genetic status and CSF protein levels of molecular pathways linked to α-Syn proteostasis. Overall, 85% of PD and 86% of DLB patients showed positive RT-QuIC α-Syn seeding activity. Seeding profiles were significantly associated with mutation status across the spectrum of genetic LBD. In PD patients, we detected positive α-Syn seeding in 93% of patients carrying severe GBA mutations, in 78% with LRRK2 mutations, in 59% carrying heterozygous mutations in recessive genes, and in none of those with bi-allelic mutations in recessive genes. Among PD patients, those with severe GBA mutations showed the highest seeding activity based on RT-QuIC kinetic parameters and the highest proportion of samples with 4 out of 4 positive replicates. In DLB patients, 100% with GBA mutations showed positive α-Syn seeding compared to 79% of wildtype DLB. Moreover, we found an association between α-Syn seeding activity and reduced CSF levels of proteins linked to α-Syn proteostasis, specifically lysosome-associated membrane glycoprotein 2 and neurosecretory protein VGF. These findings highlight the value of α-Syn seeding activity as an in-vivo marker of Lewy-body pathology and support its use for patient stratification in clinical trials targeting α-Syn. Supplementary Information The online version contains supplementary material available at 10.1186/s40478-021-01276-6.

MDS Clinical Diagnostic Criteria for Parkinson's Disease (S19.001)

Abstract: Objective To present the International Parkinson and Movement Disorder Society (MDS) Clinical Diagnostic Criteria for Parkinson9s disease. Background Although several diagnostic criteria for Parkinson9s disease have been proposed, none have been officially adopted by an official Parkinson society. Moreover, the commonest-used criteria, the UK brain bank, were created more than 25 years ago. In recognition of the lack of standard criteria, the MDS initiated a task force to design new diagnostic criteria for clinical Parkinson9s disease. Methods/Results The MDS-PD Criteria are intended for use in clinical research, but may also be used to guide clinical diagnosis. The benchmark is expert clinical diagnosis; the criteria aim to systematize the diagnostic process, to make it reproducible across centers and applicable by clinicians with less expertise. Although motor abnormalities remain central, there is increasing recognition of non-motor manifestations; these are incorporated into both the current criteria and particularly into separate criteria for prodromal PD. Similar to previous criteria, the MDS-PD Criteria retain motor parkinsonism as the core disease feature, defined as bradykinesia plus rest tremor and/or rigidity. Explicit instructions for defining these cardinal features are included. After documentation of parkinsonism, determination of PD as the cause of parkinsonism relies upon three categories of diagnostic features; absolute exclusion criteria (which rule out PD), red flags (which must be counterbalanced by additional supportive criteria to allow diagnosis of PD), and supportive criteria (positive features that increase confidence of PD diagnosis). Two levels of certainty are delineated: Clinically-established PD (maximizing specificity at the expense of reduced sensitivity), and Probable PD (which balances sensitivity and specificity). Conclusion The MDS criteria retain elements proven valuable in previous criteria and omit aspects that are no longer justified, thereby encapsulating diagnosis according to current knowledge. As understanding of PD expands, criteria will need continuous revision to accommodate these advances. Disclosure: Dr. Postuma has received personal compensation for activities with Roche Diagnostics Corporation and Biotie Therapies. Dr. Berg has received research support from Michael J. Fox Foundation, the Bundesministerium fur Bildung und Forschung (BMBF), the German Parkinson Association and Novartis GmbH.

Challenges in the diagnosis of Parkinson's disease

Abstract: Parkinson's disease is the second most common neurodegenerative disease and its prevalence has been projected to double over the next 30 years. An accurate diagnosis of Parkinson's disease remains challenging and the characterisation of the earliest stages of the disease is ongoing. Recent developments over the past 5 years include the validation of clinical diagnostic criteria, the introduction and testing of research criteria for prodromal Parkinson's disease, and the identification of genetic subtypes and a growing number of genetic variants associated with risk of Parkinson's disease. Substantial progress has been made in the development of diagnostic biomarkers, and genetic and imaging tests are already part of routine protocols in clinical practice, while novel tissue and fluid markers are under investigation. Parkinson's disease is evolving from a clinical to a biomarker-supported diagnostic entity, for which earlier identification is possible, different subtypes with diverse prognosis are recognised, and novel disease-modifying treatments are in development.

Biomarkers for neurodegenerative diseases.

Abstract: Biomarkers for neurodegenerative diseases are needed to improve the diagnostic workup in the clinic but also to facilitate the development and monitoring of effective disease-modifying therapies. Positron emission tomography methods detecting amyloid-β and tau pathology in Alzheimer's disease have been increasingly used to improve the design of clinical trials and observational studies. In recent years, easily accessible and cost-effective blood-based biomarkers detecting the same Alzheimer's disease pathologies have been developed, which might revolutionize the diagnostic workup of Alzheimer's disease globally. Relevant biomarkers for α-synuclein pathology in Parkinson's disease are also emerging, as well as blood-based markers of general neurodegeneration and glial activation. This review presents an overview of the latest advances in the field of biomarkers for neurodegenerative diseases. Future directions are discussed regarding implementation of novel biomarkers in clinical practice and trials.

Ultrasensitive RT-QuIC assay with high sensitivity and specificity for Lewy body-associated synucleinopathies.

Abstract: The clinical diagnosis of synucleinopathies, including Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), is challenging, especially at an early disease stage, due to the heterogeneous and often non-specific clinical manifestations. The discovery of reliable specific markers for synucleinopathies would consequently be of great aid to the diagnosis and management of these disorders. Real-Time Quaking-Induced Conversion (RT-QuIC) is an ultrasensitive technique that has been previously used to detect self-templating amyloidogenic proteins in the cerebrospinal fluid (CSF) and other biospecimens in prion disease and synucleinopathies. Using a wild-type recombinant α-synuclein as a substrate, we applied RT-QuIC to a large cohort of 439 CSF samples from clinically well-characterized, or post-mortem verified patients with parkinsonism or dementia. Of significance, we also studied patients with isolated REM sleep behavior disorder (iRBD) (n = 18) and pure autonomic failure (PAF) (n = 28), representing clinical syndromes that are often caused by a synucleinopathy, and may precede the appearance of parkinsonism or cognitive decline. The results show that our RT-QuIC assay can accurately detect α-synuclein seeding activity across the spectrum of Lewy Body (LB)-related disorders (LBD), including DLB, PD, iRBD, and PAF, with an overall sensitivity of 95.3%. In contrast, all but two patients with MSA showed no α-synuclein seeding activity in the applied experimental setting. The analysis of the fluorescence response reflecting the amount of α-synuclein seeds revealed no significant differences between the clinical syndromes associated with LB pathology. Finally, the assay demonstrated 98% specificity in a neuropathological cohort of 101 cases lacking LB pathology. In conclusion, α-synuclein RT-QuIC provides an accurate marker of synucleinopathies linked to LB pathology and may have a pivotal role in the early discrimination and management of affected patients. The finding of no α-synuclein seeding activity in MSA seems to support the current view that MSA and LBD are associated with different conformational strains of α-synuclein.

Detection of α-synuclein in CSF by RT-QuIC in patients with isolated rapid-eye-movement sleep behaviour disorder: a longitudinal observational study

Abstract: Summary Background Isolated rapid-eye-movement (REM) sleep behaviour disorder (IRBD) can be part of the prodromal stage of the α-synucleinopathies Parkinson's disease and dementia with Lewy bodies. Real-time quaking-induced conversion (RT-QuIC) analysis of CSF has high sensitivity and specificity for the detection of misfolded α-synuclein in patients with Parkinson's disease and dementia with Lewy bodies. We investigated whether RT-QuIC could detect α-synuclein in the CSF of patients with IRBD and be used as a biomarker of prodromal α-synucleinopathy. Methods In this longitudinal observational study, CSF samples were obtained by lumbar puncture from patients with video polysomnography-confirmed IRBD recruited at a specialised sleep disorders centre in Barcelona, Spain, and from controls free of neurological disease. CSF samples were stored until analysed using RT-QuIC. After lumbar puncture, participants were assessed clinically for neurological status every 3–12 months. Rates of neurological disease-free survival were estimated using the Kaplan-Meier method. Disease-free survival rates were assessed from the date of lumbar puncture to the date of diagnosis of any neurodegenerative disease, or to the last follow-up visit for censored observations. Findings 52 patients with IRBD and 40 healthy controls matched for age (p=0·20), sex (p=0·15), and duration of follow-up (p=0·27) underwent lumbar puncture between March 23, 2008, and July 16, 2017. The CSF α-synuclein RT-QuIC assay was positive in 47 (90%) patients with IRBD and in four (10%) controls, resulting in a sensitivity of 90·4% (95% CI 79·4–95·8) and a specificity of 90·0% (95% CI 76·9–96·0). Mean follow-up from lumbar puncture until the end of the study (July 31, 2020) was 7·1 years (SD 2·8) in patients with IRBD and 7·7 years (2·9) in controls. During follow-up, 32 (62%) patients were diagnosed with Parkinson's disease or dementia with Lewy bodies a mean 3·4 years (SD 2·6) after lumbar puncture, of whom 31 (97%) were α-synuclein positive at baseline. Kaplan-Meier analysis showed that patients with IRBD who were α-synuclein negative had lower risk for developing Parkinson's disease or dementia with Lewy bodies at 2, 4, 6, 8, and 10 years of follow-up than patients with IRBD who were α-synuclein positive (log-rank test p=0·028; hazard ratio 0·143, 95% CI 0·019–1·063). During follow-up, none of the controls developed an α-synucleinopathy. Kaplan-Meier analysis showed that participants who were α-synuclein negative (ie, five patients with IRBD plus 36 controls) had lower risk of developing Parkinson's disease or dementia with Lewy bodies at 2, 4, 6, 8 and 10 years after lumbar puncture than participants who were α-synuclein positive (ie, 47 patients with IRBD plus four controls; log-rank test p Interpretation In patients with IRBD, RT-QuIC detects misfolded α-synuclein in the CSF with both sensitivity and specificity of 90%, and α-synuclein positivity was associated with increased risk of subsequent diagnosis of Parkinson's disease or dementia with Lewy bodies. Detection of α-synuclein in the CSF represents a potential prodromal marker of Parkinson's disease and dementia with Lewy bodies. If these findings are replicated in additional cohorts, detection of CSF α-synuclein by RT-QuIC could be used to enrich IRBD cohorts in neuroprotective trials, particularly when assessing interventions that target α-synuclein. Funding Department of Health and Social Care Policy Research Programme, the Scottish Government, and the Weston Brain Institute.