Periodontal Bacteria Proteomics in Thrombi from Ischemic Stroke Patients.

OBEJECTIVE: To characterize periodontal bacterial proteins in ischemic stroke thrombi and explore differences according to stroke etiology. METHODS: Thrombotic samples were obtained from nine severe periodontal patients with acute ischemic stroke (large-artery atherosclerosis, cardioembolic and undetermined source; 3 patients per stroke subtype) during mechanical thrombectomy. Samples were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Quantitative proteomic profiling was performed by sequential window acquisition of all theoretical mass spectra (SWATH-MS), focusing on proteins from five periodontal bacteria: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia, and Treponema denticola. Protein expression was compared across thrombus etiologies, and differentially expressed proteins were further analyzed in silico to explore their functions and interactions. RESULTS: A total of 136 bacterial proteins were quantified, predominantly from A. actinomycetemcomitans (112). Sixteen proteins showed differential expression (p < 0.05), mainly from this species. These were primarily associated with transcription, translation, and stress response mechanisms, including oxidative stress resistance. Few proteins from other species were differentially expressed, mostly related to structural and basic metabolic functions, except for a collagenase from T. forsythia in large-artery atherosclerosis stroke thrombi. CONCLUSIONS: SWATH-MS-based proteomic analysis revealed the presence of periodontal bacterial proteins in ischemic stroke thrombi, with a predominance of Aggregatibacter actinomycetemcomitans.