Is there any intra-aneuvrysmal blood marker of aneuvrysm wall inflammation? Crossed analysis between transcriptomic and proteomic data

Background and purpose Intracranial aneurysm formation, growth and rupture are incompletely understood. Inflammation plays a key role in the formation and rupture of intracranial aneurysms. Inflammation is mediated through several factors such as cytokines, chemokines and growth factors. The purpose of this study was to determine if these inflammatory proteins were increased in the lumen of human intracranial aneurysm and correlate these data with gene expression regulation (transcriptomic) at tissue level. Methods The concentration of 27 inflammatory proteins in blood samples drawn from the lumen of human intracranial unruptured aneurysms of 21 patients were compared with blood samples from the femoral arteries of the same patients. We compared these proteomic data from intra-aneurysmal blood with transcriptomic data obtained by RNA sequencing of 7 human unruptured aneurysm walls and 6 human controls cortical arteries. Results The mean serum concentration of Il-1ra, IL-2, IL-5, IL-6 FGF-basic, GM-CSF, MCP-1, TNF-I± and MIP-1I± was significantly higher in samples taken from cerebral aneurysms compared to femoral arteries. In our transcriptomic analysis, we found a significant upregulation of IL-2 gene and IL-5 gene (coding for IL-2 and IL-5) in aneurysm walls compared with controls cortical arteries. Conclusion Higher concentration of inflammatory proteins was found in intra-aneurysmal sampling compared with femoral sampling. Transcriptomic data showed an upregulation of IL-2 gene and IL-5 gene in aneurysm walls compared with controls cortical arteries. Our findings suggest that we may detect intra-aneurysmal blood marker of aneurysm wall inflammation.