Plasma PCSK9 levels increase following percutaneous coronary interventions

Background

Beside its role in cholesterol homeostasis, Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) has been associated with the processes of vascular inflammation and atherosclerosis. The protein is expressed in endothelial cells, smooth muscle cells and macrophages and it is detected inside the human atherosclerotic plaque.

Purpose

We aimed to investigate the effect of acute inflammation associated with plaque rupture and vascular injury during elective percutaneous coronary intervention (PCI) on plasma levels of PCSK9 in patients with coronary artery disease (CAD).

Methods

We measured PCSK9, C-reactive protein (CRP), Interleukin-6 (IL-6) and high-sensitivity cardiac Troponin T (hs-cTnT) plasma levels immediately before and 18–24 hours after PCI via the radial approach, in 68 consecutive patients with stable CAD referred for elective PCI of a de novo lesion in a native coronary artery. Patients with unstable coronary syndrome <3 months old, baseline inflammatory condition, malignancy, auto-immune disease or intervention via the femoral access, were excluded.

Results

All patients were treated with balloon angioplasty and implantation of a second-generation drug eluting stent (DES). Baseline plasma levels of PCSK9 were higher in women and in patients treated with statins. At 18–24 hours after the procedure, plasma levels of PCSK9, CRP, IL-6 and hs-cTnT increased significantly compared to baseline (table). The change (elevation) in CRP plasma levels was statistically correlated with that of IL-6 (r=0.33; p=0.006) and with that of hs-cTnT (r=0.28; p=0.023). However, there was no correlation between the change (elevation) in plasma PCSK9 levels and those of IL-6 (r=−0.09; p=0.47), CRP (r=0.01; p=0.9), and hs-cTnT (r=0.1; p=0.41).

Conclusions

Plasma levels of PCSK9 increased by 26% following PCI with DES. That elevation was however, not correlated with the degree of myocardial injury (hs-cTnT) or of inflammation (IL-6 and CRP). The mechanism underlying PCK9 elevation post PCI requires further investigation.

Funding Acknowledgement

Type of funding sources: None.

[After the LDL receptor and apolipoprotein B, autosomal dominant hypercholesterolemia reveals its third protagonist: PCSK9]

The genes encoding the low-density lipoproteins receptor and its ligand apolipoprotein B, have been the only two genes classically implicated in autosomal dominant hypercholesterolemia. We have identified in 2003, the third gene implicated in this disease: PCSK9 (Proprotein Convertase Subtilin Kexin 9). Several mutations (p.S127R, p.F216L, p.D374Y...) of this gene have been reported to cause hypercholesterolemia by a gain of function leading to a reduction of LDL receptor levels. Other variations of PCSK9 are conversely associated with hypocholesterolemia particularly the non-sense p.Y142X and p.C679X mutations found in 2% of black Americans and associated with a decrease of LDL levels and coronary heart diseases. PCSK9 substrates and exact role have not been elucidated yet, but it seems that PCSK9 is definitely a major actor in cholesterol homeostasis. PCSK9 inhibitors might constitute new therapeutic targets that would decrease plasma LDL cholesterol levels and be synergistic with statin drugs.