Introduction: Inflammation plays an important role in the induction of CAD and the progression to deadly coronary syndromes. Cytokines are key mediators of inflammation, both in pro- and anti-inflammatory capacities. HDL has a vital role in the maintenance of cardiovascular health, and recent discoveries highlight the diversity of HDL functions to include the transport of lipid signaling molecules, microRNAs, and other effectors of metabolic regulation. Given the importance of HDL in transporting molecules involved in cardiovascular health, we questioned if HDL has a direct role in transporting cytokines and effecting inflammatory responses in CAD.
Hypothesis: HDL plays an important role in the transport of cytokines involved in CAD.
Methods: To explore the role of HDL in arterial inflammation, we profiled the abundance of 35 cytokines in plasma and HDL of men and women with and without CAD. We analyzed whole plasma and native HDL isolated using a selected-affinity immunosorption technique from patients who suffered myocardial infarction at an early age (<60 years, male n=19; female n=20) and control patients (male n=10, female n=10). Samples were assayed by multiplex array technology for quantification of cytokines.
Results: Of 35 cytokines analyzed, 25 appear to be significantly transported in HDL. Three cytokines (IL-12, MCP-1, and IL-RA) are excluded from HDL and are only detectable in plasma. IL-3 and IL-7 are predominately associated with HDL and are elevated in both males and females with MI. There are differences in several HDL-associated cytokines that appear to be sex-dependent.
Conclusions: We have discovered that a number of cytokines are transported in HDL complexes. Significant elevations or decreases in a number of these cytokines are observed in patients with CAD, and vary in abundance between males and females.