Investigations in plaque erosion and ruptured in acute coronary syndromes via novel methods in multimodal and VDJ sequencing
Authors: De Vore L , Gerhart T , Abdelwahed Y , Stapmanns P , Wolfram C , Becker K , Franitz M , Georgomanolis T , Landmesser U , Leistner D , Winkels H 
Published: October 2022

Abstract

Background
Acute coronary syndromes (ACS) remain the most devastating clinical manifestation of cardiovascular disease, the most common cause of global mortality. ACS frequently arises from rupture of the coronary fibrous cap, in which a highly thrombogenic necrotic core is exposed to circulating blood, thereby triggering thrombus formation and impairing myocardial perfusion. While inflammation has been implicated as a key mechanism contributing to atherosclerotic plaque vulnerability and rupture, the underlying mechanisms leading to coronary plaque erosion, another form of ACS, are not well understood. In recent findings, flow cytometric (FACS) analysis of blood from the site of patients with culprit lesion plaque erosion showed significant enrichment of both CD4+ and CD8+ T-lymphocytes (+8.1% and +11.2%, respectively, both P&lt;0.05) as well as effector molecules such as granzyme A (+22.4%), perforin (+58.8%), and granulysin (+75.4%) as compared with patients with plaque rupture culprit lesion. The proximity of eroded lesions to coronary bifurcations seen by optical coherence tomography provides further elucidations linking shear stress alterations to the occurrence of erosional ACS.

Purpose
We aim to further explore the underlying immune cell mechanisms of coronary plaque erosion via a novel single cell multi-omic approach, never before established from samples aspirated from the arterial sheath.

Methods
Patients presenting with Myocardial Infarction underwent emergent coronary angiography & percutaneous coronary intervention. Infarction was characterized as either coronary plaque rupture or erosion by optical coherence tomography, in which then blood samples were obtained by being aspirated directly along the arterial sheath. Peripheral blood mononuclear cells were isolated via density gradient within four hours of sample aspiration and cryopreserved. Samples from 24 patients were promptly thawed, washed and incubated with 137 oligonucleotide barcoded antibodies to detect surface protein expression as well as a cellular hashtag antibody. Bioinformatic integration of single cell epitope and transcriptome information was performed derived from custom pipelines.

Results
Our analysis found 32 unique leukocyte clusters that allowed us to rigorously compare each patients sequenced single cell data -totaling approximately 140,000 singe cells. Additionally, the discovery of T cell oligoclonality amongst certain disease patients alludes to antigen-specific activation. We also observed increased CCL4 expression in CD8+ T-lymphocytes within erosional ACS.

Conclusion
Our high-parametric immune cell analysis shows distinct differences in the adaptive immune system, particularly CD8+ T-lymphocytes and their effector molecules, in the pathogenesis of erosional versus ruptured ACS. Furthermore, our observations found on the oligoclonal expansion of T cell clones aids us to further elucidate underlying mechanisms of culprit lesion formation in ACS.

Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): DGK - German Cardiac SocietyDGF - TRR 259 Aortic Disease German Research Foundation