Identification of putative baroreceptors in human aortic arch by histological and omics analyses

Baroreflex regulates blood pressure and heartbeat through specific mechanosensitive baroreceptors. However, the current knowledge is derived only from animal experiments. No data about human aortic baroreceptors have been reported so far. Therefore, in this study, we performed extended histological, proteomics and transcriptomics analyses of the aortic arch to identify potential human baroreceptors. Three healthy human aortic arches from autopsies, six abdominal aortic aneurysms and four control abdominal aortic tissue samples from our vascular biobank were analysed. For histological analyses, antibodies against various neuronal markers were used. Laser capture microdissection and macrodissection were performed to selectively analyse nerves in the adventitia of the human aorta using proteomics and RNA sequencing. Histological analysis revealed a heterogeneous distribution of nerves in the adventitia along the entire aortic arch, predominantly in the ascending aorta up to the left subclavian artery. Proteome analysis identified three putative human baroreceptors PIEZO1, TRPV2, and TRPM4. Transcriptomics confirmed that these ion channels do not originate from cells within the aortic wall but presumably from the cell body of the vagus nerve. Interestingly, these ion channels were also detected in the healthy abdominal aorta and abdominal aneurysm without any significant differences in their abundance. Our study identified, for the first time, putative baroreceptors in the human aortic arch. Further studies are necessary to validate our current results and elucidate the role of these putative baroreceptors in the human aortic arch.