Elevated Circulatory Levels of UL16 Binding Protein 1 Positive Microparticles Are Associated With Acute Myocardial Infarction and its Severity

Abstract

Background/aim: Atherosclerosis is a vascular inflammatory disease characterized by the activation and stress of various inflammatory cells, leading to the development of coronary artery disease and subsequently acute myocardial infarction (AMI). Among AMI cases, ST-segment elevation myocardial infarction (STEMI) is typically more severe than non-STEMI (NSTEMI). UL16-binding proteins (ULBPs), which are NKG2D ligands, can be expressed on the surface of stressed and activated cells, prompting these cells to generate microparticles (MPs). Consequently, MPs carrying ULBPs, particularly ULBP1 (ULBP1⁺ MPs), may be released into the bloodstream. This study aimed to investigate the association between ULBP1⁺ MPs and the presence of AMI and its severity.

Materials and methods: We recruited 58 AMI patients and 45 age-matched control subjects. Levels of ULBP1⁺ MPs and ULBP1⁺ MPs originating from T lymphocytes (ULBP1⁺ TMPs) were measured using flow cytometry.

Results: Both ULBP1⁺ MP and ULBP1⁺ TMP levels were significantly elevated in AMI patients compared to controls. Elevated levels of these MPs were independent risk factors for AMI with odds ratios (OR) of 4.3 (95%CI=1.5-12.3) for ULBP1⁺ MPs and 5.8 (95%CI=2.0-17.0) for ULBP1⁺ TMPs. Additionally, ULBP1⁺ TMP levels were significantly higher in STEMI patients compared to NSTEMI patients, with an independent association observed between ULBP1⁺ TMPs and STEMI (OR=3.9; 95%CI=1.2-12.8).

Conclusion: Elevated levels of ULBP1⁺ MPs and ULBP1⁺ TMPs are associated with AMI and its severity. These biomarkers could serve as indicators of vulnerable plaques that lead to AMI.

Keywords: NKG2D; ULBP1+ MPs; ULBP1+ TMPs; acute myocardial infarction; atherosclerosis; inflammation; microparticles.