Ultrasensitive detection of aggregated α-synuclein using quiescent seed amplification assay for the diagnosis of Parkinson's disease.

BACKGROUND: Seed amplification assays (SAA) enable the amplification of pathological misfolded proteins, including α-synuclein (αSyn), in both tissue homogenates and body fluids of Parkinson's disease (PD) patients. SAA involves repeated cycles of shaking or sonication coupled with incubation periods. However, this amplification scheme has limitations in tracking protein propagation due to repeated fragmentation. METHODS: We introduced a modified form of SAA, known as Quiescent SAA (QSAA), and evaluated biopsy and autopsy samples from individuals clinically diagnosed with PD and those without synucleinopathies (control group). Brain biopsy samples were obtained from 14 PD patients and 6 controls without synucleinopathies. Additionally, skin samples were collected from 214 PD patients and 208 control subjects. Data were analyzed from April 2019 to May 2023. RESULTS: QSAA successfully amplified αSyn aggregates in brain tissue sections from mice inoculated with pre-formed fibrils. In the skin samples from 214 PD cases and 208 non-PD cases, QSAA demonstrated high sensitivity (90.2%) and specificity (91.4%) in differentiating between PD and non-PD cases. Notably, more αSyn aggregates were detected by QSAA compared to immunofluorescence with the pS129-αSyn antibody in consecutive slices of both brain and skin samples. CONCLUSION: We introduced the new QSAA method tailored for in situ amplification of αSyn aggregates in brain and skin samples while maintaining tissue integrity, providing a streamlined approach to diagnosing PD with individual variability. The integration of seeding activities with the location of deposition of αSyn seeds advances our understanding of the mechanism underlying αSyn misfolding in PD.

A skin-specific α-Synuclein seeding amplification assay for diagnosing Parkinson's disease.

The seeding amplification assay (SAA) has recently emerged as a valuable tool for detecting α-synuclein (αSyn) aggregates in various clinically accessible biospecimens. Despite its efficiency and specificity, optimal tissue-specific conditions for distinguishing Parkinson's disease (PD) from non-PD outside the brain remain underexplored. This study systematically evaluated 150 reaction conditions to identify the one with the highest discriminatory potential between PD and non-synucleinopathy controls using skin samples, resulting in a modified SAA. The streamlined SAA achieved an overall sensitivity of 92.46% and specificity of 93.33% on biopsy skin samples from 332 PD patients and 285 controls within 24 h. Inter-laboratory reproducibility demonstrated a Cohen's kappa value of 0.87 (95% CI 0.69-1.00), indicating nearly perfect agreement. Additionally, αSyn seeds in the skin were stable at -80 °C but were vulnerable to short-term exposure to non-ultra-low temperatures and grinding. This study thoroughly investigated procedures for sample preprocessing, seed amplification, and storage, introducing a well-structured experimental framework for PD diagnosis using skin samples.

Sublobar resection reduces the risk of postoperative cognitive dysfunction compared with lobectomy.

OBJECTIVES: Sublobar resection, including wedge resection and segmentectomy, is non-inferior to lobectomy in early-stage non-small cell lung cancer treatment. We aimed to compare the risk of postoperative cognitive dysfunction (POCD) between sublobar resection and lobectomy. METHODS: We conducted a prospective cohort study. Patients with sublobar resection or lobectomy were divided into the sublobar group or the lobar group, respectively. Cognition was assessed before and after surgery with Montreal Cognitive Assessment and Minimum Mental State Examination tests. POCD is defined as Z score of Montreal Cognitive Assessment change ≤-1.96. Propensity score matching (PSM) was performed to make demographics well-balanced between the 2 groups. RESULTS: A total of 335 patients were enrolled. Both the postoperative 1-day POCD rate (sublobar 5.5% vs lobar 18.2%, P < 0.001) and the postoperative 1-month POCD rate (sublobar 7.9% vs lobar 21.8%, P < 0.001) were significantly lower in the sublobar group compared with lobar group, with demographics unbalanced between the 2 groups. In the 133 demographics-matched pairs obtained by PSM, both the postoperative 1-day POCD rate (sublobar 5.3% vs lobar 17.3%, P = 0.005) and the postoperative 1-month POCD rate (sublobar 8.3% vs lobar 18.8%, P = 0.018) remained significantly lower in the sublobar group than in the lobar group. The incidences of postoperative 1-day (P = 0.109) and postoperative 1-month (P = 0.026) Minimum Mental State Examination abnormity were also lower in the sublobar group than in the lobar group but only the latter was with statistical significance after PSM. CONCLUSIONS: Sublobar resection has an advantage over lobectomy in preventing POCD. Our findings might be a reference for selecting the most suitable type of resection for non-small-cell lung cancer patients.