C-Reactive Protein and Inflammatory Cytokines during Percutaneous Coronary Intervention

BACKGROUND: C-reactive protein (CRP) is significantly associated with cardiovascular diseases; however, whether CRP plays a causal role in coronary artery disease has yet to be determined. In addition, the relationship between CRP, atherosclerosis, and inflammation remains controversial. METHODS AND RESULTS: Serum interleukin (IL)-6, IL-1β, and CRP levels were determined in 160 patients at time points around percutaneous coronary intervention (PCI) with drug-eluting stent implantation. The levels were found to be at peak at 24 h post-PCI and gradually declined to the level before PCI at day 30 post-PCI. These inflammation markers around PCI have no statistical difference in the different postdilation pressures (≤14, 14-18, and ≥18 atm) and stent number (1 and ≥2 stents) groups. Treatment of cultured human vascular smooth muscle cells (VSMCs) with a combination of IL-6 and IL-1β at concentrations associated with PCI did not result in any significant change in the CRP mRNA levels. The IL-6-augmented CRP expression in human internal mammary arteries (IMAs) stretched with a mechanical strength of 3 g was blocked by the nuclear factor-κB (NF-κB) peptide inhibitor SN50 and not by the inactive SN50 analog SN50M. IL-6 treatment increased NF-κB activity in human IMAs stretched with 3 g, and this effect was further blocked by stretch-activated channel (SAC) inhibitors (streptomycin or GdCl3) and SN50. CONCLUSIONS: The current study provides evidence that increased serum IL-6, IL-1β, and CRP levels around PCI are not different between different postdilation pressure and stent number groups. The combination of IL-6 and IL-1β at concentrations associated with PCI cannot induce CRP expression in human VSMCs, but they can augment mechanical strain-induced CRP synthesis via the SAC-NF-κB pathway in human IMAs.