👤 Anna Dénes

Cognitive outcomes following brain insult are shaped by a range of factors, including genetic predispositions. Emerging evidence indicates that specific genetic variants may affect the susceptibility to cognitive impairment in individual patients. In this systematic review we summarize the evidence for genetic variants on cognitive outcomes following brain insults. A systematic search was conducted in PubMed, Embase, PsycINFO, bioRxiv, medRxiv, reference lists, and ClinicalTrials.gov to identify studies published before June 14, 2023, reporting associations between genetic variants and cognitive outcomes following brain insults. Only studies conducted in humans and published in English were included. A broad definition of brain insults was applied, with a primary focus on stroke, traumatic brain injury (TBI), and brain tumors. All articles underwent bias assessment using the JBI critical appraisal tools. Of the 121 studies included, 80 (66%) were rated as low risk of bias. The APOE gene was investigated in 56% of TBI studies, 52% of stroke studies, and 43% of studies on other brain injuries. Of the 74 studies on APOE, 50 (68%) focused on the ε4 allele, with 39 studies (87%) reporting associations between the ε4 allele and worse cognitive outcomes. The BDNF rs6265 polymorphism was examined in 18 studies, 15 of which reported significant effects on cognitive outcomes. However, the direction of these effects was inconsistent, with seven studies linking the G allele and seven the A allele to worse cognitive outcomes. For the COMT rs4680 polymorphism, nine out of 12 studies reported worsened cognitive outcomes linked to the G allele, while several reported a protective association for the A allele. Injury- and population-specific patterns were not consistent. This systematic review suggests that APOE-ε4 and potentially the G allele of COMT rs4680 are associated with poor cognitive outcomes following brain insults. The type of brain injury does not appear to influence whether genetic variants predispose to favorable or unfavorable cognitive outcomes. Future research may benefit from focusing on these markers, particularly in larger datasets, to validate these findings. Show less

In this study we tested whether a protein corona is formed around extracellular vesicles (EVs) in blood plasma. We isolated medium-sized nascent EVs of THP1 cells as well as of Optiprep-purified platelets, and incubated them in EV-depleted blood plasma from healthy subjects and from patients with rheumatoid arthritis. EVs were subjected to differential centrifugation, size exclusion chromatography, or density gradient ultracentrifugation followed by mass spectrometry. Plasma protein-coated EVs had a higher density compared to the nascent ones and carried numerous newly associated proteins. Interactions between plasma proteins and EVs were confirmed by confocal microscopy, capillary Western immunoassay, immune electron microscopy and flow cytometry. We identified nine shared EV corona proteins (ApoA1, ApoB, ApoC3, ApoE, complement factors 3 and 4B, fibrinogen α-chain, immunoglobulin heavy constant γ2 and γ4 chains), which appear to be common corona proteins among EVs, viruses and artificial nanoparticles in blood plasma. An unexpected finding of this study was the high overlap of the composition of the protein corona with blood plasma protein aggregates. This is explained by our finding that besides a diffuse, patchy protein corona, large protein aggregates also associate with the surface of EVs. However, while EVs with an external plasma protein cargo induced an increased expression of TNF-α, IL-6, CD83, CD86 and HLA-DR of human monocyte-derived dendritic cells, EV-free protein aggregates had no effect. In conclusion, our data may shed new light on the origin of the commonly reported plasma protein 'contamination' of EV preparations and may add a new perspective to EV research. Show less