SAA is an acute phase protein that elevates under inflammatory circumstance. The serum level of SAA was associated with the progression of inflammation in numerous diseases. However, little attention was paid to the correlation between SAA and ONFH. In this study, SAA was found risen in the femoral head of osteonecrosis patients through proteomics analysis and further confirmed by ELISA. Furthermore, SAA was proven affecting bone metabolism in rBMSCs. It facilitated the proliferation of rBMSCs whereas it suppressed the osteogenic differentiation of rBMSCs and accelerated the adipogenic differentiation of rBMSCs. Thus, we deem that serum amyloid A, which is a vital acute phase protein in inflammation, affected bone metabolis and plays an imperative role in the pathophysiological process of ONFH.

Recent studies have been able to detect α-synuclein (αSyn) seeding in formaldehyde-fixed paraffin-embedded (FFPE) tissues from patients with synucleinopathies using seed amplification assays (SAAs), but with relatively low sensitivity due to limited protein extraction efficiency. With the aim of introducing an alternative option to frozen tissues, we developed a streamlined protein extraction protocol for evaluating disease-specific seeding in FFPE human brain. We evaluated the protein extraction efficiency of different tissue preparations, deparaffinizations, and protein extraction buffers using formaldehyde-fixed and FFPE tissue of a single Lewy body disease (LBD) subject. Alternatively, we incorporated heat-induced antigen-retrieval and dissociation using a commercially available kit. Our novel protein extraction protocol has been optimized to work with 10 sections of 4.5-µm-thickness or 2-mm-diameter micro-punch of FFPE tissue that can be used to seed SAAs. We demonstrated that extracted proteins from FFPE still preserve seeding potential and further show disease-specific seeding in LBD and multiple system atrophy. To the best of our knowledge, our study is the first to recapitulate disease-specific αSyn seeding behavior in FFPE human brain, with structural validation. Our findings open new perspectives in re-evaluating archived human brain tissue, extending the disease-specific seeding assays to larger cohorts to facilitate molecular subtyping of synucleinopathies.

The acute phase protein Serum Amyloid A (SAA) is synthesised by the liver in response to inflammatory stimuli. Previous studies have revealed that SAA may be a better predictive marker for the course of inflammatory bowel disease (IBD) compared to C-reactive protein (CRP). Hence, this retrospective monocentric study evaluated whether SAA correlates with biomarkers like faecal calprotectin (FC), CRP, the Neutrophil to Lymphocyte ratio (NLR) and clinical disease activity of IBD patients. Serum samples from the IBD outpatient clinic of the University Hospital Heidelberg were analysed for their SAA concentrations if a FC concentration measurement was available from 14 days before or after collection of the serum sample. 306 serum samples from 265 patients (166 with Crohn’s disease, 91 with ulcerative colitis, 8 with IBD unclassified) met the inclusion criteria. There was a significant positive correlation between SAA and FC, CRP, the NLR and the Simple Clinical Colitis Activity Index. The cut-off for SAA serum concentration at 4.55 mg/l achieved a sensitivity of 57.5% and a specificity of 69.7% for the detection of active inflammation in IBD. SAA may be used as an additional biomarker in the disease monitoring strategy of IBD patients, especially in patients with low CRP concentrations.