PO31 Potential gut-derived fungal signatures in atherosclerotic thrombi: implications for a trojan horse pathway

Background Atherosclerosis poses a significant global health burden, urging the need to discover new therapeutic targets. Emerging evidence suggests associations between gut microbiota and direct vascular bacterial infection in atherosclerosis. However, antibiotics failed to treat atherosclerosis, underscoring the complexity of the microbial community that promotes atherogenesis1. The involvement of fungi in plaque development remains largely understudied, with limited research using low-throughput methods. Purpose In this study, we aimed to investigate the potential of fungi as contributors to coronary artery infection–mediated atherogenesis by applying whole-metagenome analysis of aspirated thrombi from patients with atherosclerosis. Methods This study recruited nine patients with ST-segment–elevation myocardial infarction (STEMI) and one patient with non-STEMI. DNA was extracted from five non-host-depleted samples with prior mechanical lysis in liquid nitrogen and four host-depleted samples with prior collagenase treatment, followed by whole-genome amplification. In addition, one sample was extracted using both methods. Eight libraries passed QC and were sequenced using the Illumina NovaSeq platform. Sequencing reads underwent quality trimming and stringent host read removal. Fungal hits were identified via Bowtie2 mapping to the fungal RefSeq database, validated by BLAST and Kraken2. Species-level identification was performed by reference genome alignment. Results A total of twenty-one fungal genera were identified in six samples, whereas two samples showed no detectable fungi. Alternaria was the most prevalent genus detected in five samples (62.5%) and exhibited the highest relative abundance in two of them. The second most prevalent genus was Aspergillus, detected in four samples (50%). It displayed high relative abundance in two of these samples and co-occurred with Candida. Additionally, Malassezia was detected in three samples (37.5%). Conclusions These genera, except for Candida, were first identified in atherosclerotic thrombi in our study. Furthermore, compositional alterations of these genera, along with Exophiala, have been previously documented in the gut of patients with atherosclerosis, indicating a possible link between gut dysbiosis and direct vessel infection in atherosclerosis. Reinforcing this connection, Candida has been shown to evade monocytes, disseminate to distant organs through the “Trojan horse” mechanism, which is also associated with gut dysbiosis, and induce foam cell formation in vitro. An additional potential pathway involves fungal translocation as a sequela of long COVID syndrome. Our findings suggest a possible fungal gut–vessel axis in infection-driven atherosclerosis, involving fungus-laden monocytes and post-COVID-19 fungal translocation. This pathway could represent a novel therapeutic target, warranting further investigation.